WorldWideScience

Sample records for quiescent prominence observed

  1. Quiescent Prominences in the Era of ALMA: Simulated Observations Using the 3D Whole-prominence Fine Structure Model

    Science.gov (United States)

    Gunár, Stanislav; Heinzel, Petr; Mackay, Duncan H.; Anzer, Ulrich

    2016-12-01

    We use the detailed 3D whole-prominence fine structure model to produce the first simulated high-resolution ALMA observations of a modeled quiescent solar prominence. The maps of synthetic brightness temperature and optical thickness shown in the present paper are produced using a visualization method for synthesis of the submillimeter/millimeter radio continua. We have obtained the simulated observations of both the prominence at the limb and the filament on the disk at wavelengths covering a broad range that encompasses the full potential of ALMA. We demonstrate here extent to which the small-scale and large-scale prominence and filament structures will be visible in the ALMA observations spanning both the optically thin and thick regimes. We analyze the relationship between the brightness and kinetic temperature of the prominence plasma. We also illustrate the opportunities ALMA will provide for studying the thermal structure of the prominence plasma from the cores of the cool prominence fine structure to the prominence-corona transition region. In addition, we show that detailed 3D modeling of entire prominences with their numerous fine structures will be important for the correct interpretation of future ALMA observations of prominences.

  2. Turbulent characteristics in the intensity fluctuations of a solar quiescent prominence observed by the \\textit{Hinode} Solar Optical Telescope

    CERN Document Server

    Leonardis, Ersilia; Foullon, Claire

    2011-01-01

    We focus on Hinode Solar Optical Telescope (SOT) calcium II H-line observations of a solar quiescent prominence (QP) that exhibits highly variable dynamics suggestive of turbulence. These images capture a sufficient range of scales spatially ($\\sim$0.1-100 arc seconds) and temporally ($\\sim$16.8 s - 4.5 hrs) to allow the application of statistical methods used to quantify finite range fluid turbulence. We present the first such application of these techniques to the spatial intensity field of a long lived solar prominence. Fully evolved inertial range turbulence in an infinite medium exhibits multifractal \\emph{scale invariance} in the statistics of its fluctuations, seen as power law power spectra and as scaling of the higher order moments (structure functions) of fluctuations which have non-Gaussian statistics; fluctuations $\\delta I(r,L)=I(r+L)-I(r)$ on length scale $L$ along a given direction in observed spatial field $I$ have moments that scale as $\\sim L^{\\zeta(p)}$. For turbulence in a system that is o...

  3. A STATISTICAL STUDY OF TRANSVERSE OSCILLATIONS IN A QUIESCENT PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Hillier, A. [Kwasan and Hida Observatories, Kyoto University, Kyoto 607-8471 (Japan); Morton, R. J. [Mathematics and Information Science, Northumbria University, Pandon Building, Camden Street, Newcastle upon Tyne NE1 8ST (United Kingdom); Erdélyi, R., E-mail: andrew@kwasan.kyoto-u.ac.jp [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2013-12-20

    The launch of the Hinode satellite has allowed for seeing-free observations at high-resolution and high-cadence making it well suited to study the dynamics of quiescent prominences. In recent years it has become clear that quiescent prominences support small-amplitude transverse oscillations, however, sample sizes are usually too small for general conclusions to be drawn. We remedy this by providing a statistical study of transverse oscillations in vertical prominence threads. Over a 4 hr period of observations it was possible to measure the properties of 3436 waves, finding periods from 50 to 6000 s with typical velocity amplitudes ranging between 0.2 and 23 km s{sup –1}. The large number of observed waves allows the determination of the frequency dependence of the wave properties and derivation of the velocity power spectrum for the transverse waves. For frequencies less than 7 mHz, the frequency dependence of the velocity power is consistent with the velocity power spectra generated from observations of the horizontal motions of magnetic elements in the photosphere, suggesting that the prominence transverse waves are driven by photospheric motions. However, at higher frequencies the two distributions significantly diverge, with relatively more power found at higher frequencies in the prominence oscillations. These results highlight that waves over a large frequency range are ubiquitous in prominences, and that a significant amount of the wave energy is found at higher frequency.

  4. Spatial Damping of Linear Compressional Magnetoacoustic Waves in Quiescent Prominences

    Indian Academy of Sciences (India)

    K. A. P. Singh

    2006-06-01

    We study the spatial damping of magnetoacoustic waves in an unbounded quiescent prominence invoking the technique of MHD seismology. We consider Newtonian radiation in the energy equation and derive a fourth order general dispersion relation in terms of wavenumber . Numerical solution of dispersion relation suggests that slow mode is more affected by radiation. The high frequency waves have been found to be highly damped. The uncertainty in the radiative relaxation time, however, does not allow us to conclude if the radiation is a dominant damping mechanism in quiescent prominence.

  5. Fine structure and oscillations of a quiescent prominence

    Science.gov (United States)

    Petrov, N.; Duchlev, P.; Rompolt, B.; Rudawy, P.

    Series of H_alpha spectra and slit-jaw H_alpha filtergrams of a quiescent prominence (QP) taken at Pic du Midi Observatory on 7 November 1977 are studied. The image processing of the H_alpha filtergrams reveals an internal structure of the prominence consisting of several arches. Series of high-resolution H_alpha spectra obtained with the slit located on selected parts of one of the prominence arches chosen for Doppler shift analysis. The prominence arch show cyclic displacement along the line-of-sight (L.O.S.) direction implying Alfven string-mode oscillations.

  6. Structure, internal motion and oscillation of a quiescent prominence.

    Science.gov (United States)

    Dermendjiev, V. N.; Detchev, M.; Petrov, N.; Rompolt, B.

    Series of Hα spectra and slit-jaw Hα filtergrams of a quiescent prominence are studied. The prominence consists of several arches. One of the arches oscillates with a frequency ω = 3·10-4s and shows displacement of ±55.8 km in the line of sight direction. Its internal velocity variations are larger near the periphery of the arch. The sign and magnitude of the velocity depend strongly on the position along the slit. For interpretation of these results a model of secondary plasma flow generated by bending oscillation propagating along the arch is developed.

  7. Solar Prominences: Observations

    Directory of Open Access Journals (Sweden)

    Susanna Parenti

    2014-03-01

    Full Text Available Solar prominences are one of the most common features of the solar atmosphere. They are found in the corona but they are one hundred times cooler and denser than the coronal material, indicating that they are thermally and pressure isolated from the surrounding environment. Because of these properties they appear at the limb as bright features when observed in the optical or the EUV cool lines. On the disk they appear darker than their background, indicating the presence of a plasma absorption process (in this case they are called filaments. Prominence plasma is embedded in a magnetic environment that lies above magnetic inversion lines, denoted a filament channel. This paper aims at providing the reader with the main elements that characterize these peculiar structures, the prominences and their environment, as deduced from observations. The aim is also to point out and discuss open questions on prominence existence, stability and disappearance. The review starts with a general introduction of these features and the instruments used for their observation. Section 2 presents the large scale properties, including filament morphology, thermodynamical parameters, magnetic fields, and the properties of the surrounding coronal cavity, all in stable conditions. Section 3 is dedicated to small-scale observational properties, from both the morphological and dynamical points of view. Section 4 introduces observational aspects during prominence formation, while Section 5 reviews the sources of instability leading to prominence disappearance or eruption. Conclusions and perspectives are given in Section 6.

  8. Observed IRIS Profiles of the h and k Doublet of Mg ii and Comparison with Profiles from Quiescent Prominence NLTE Models

    Science.gov (United States)

    Vial, Jean-Claude; Pelouze, Gabriel; Heinzel, Petr; Kleint, Lucia; Anzer, Ulrich

    2016-01-01

    With the launch of the Interface Region Imaging Spectrograph (IRIS) mission, it is now possible to obtain high-resolution solar prominence spectra and to begin to distinguish the contributions of the many (apparent or not) threads that structure prominences. We aim at comparing unique observations obtained in the Mg ii h and k lines of a polar crown prominence with the radiative outputs from one-dimensional models built with non-local-thermodynamic equilibrium codes (Heinzel et al. Astron. Astrophys. 564, A132, 2014). We characterize the profiles obtained through thorough calibration procedures, with attention paid to the absolute values, full-width at half-maximum, and the ratio of k to h intensities. We also show that at the top of some structures, line-of-sight velocities of about 9 km s^{-1} can be detected. We find a range of static, low-pressure, low-thickness, low-temperature models that could fit k or h observed values, but that cannot satisfy the low observed k/h ratio. We investigate whether these low values might be explained by the inclusion of horizontal flows in small-scale threads. These flows are also necessary in another class of models, where the pressure is kept low but thickness and temperature are increased up to the observed thickness and up to 15 000 K.

  9. Quiescent and Eruptive Prominences at Solar Minimum: A Statistical Study via an Automated Tracking System

    Science.gov (United States)

    Loboda, I. P.; Bogachev, S. A.

    2015-07-01

    We employ an automated detection algorithm to perform a global study of solar prominence characteristics. We process four months of TESIS observations in the He II 304Å line taken close to the solar minimum of 2008-2009 and mainly focus on quiescent and quiescent-eruptive prominences. We detect a total of 389 individual features ranging from 25×25 to 150×500 Mm2 in size and obtain distributions of many of their spatial characteristics, such as latitudinal position, height, size, and shape. To study their dynamics, we classify prominences as either stable or eruptive and calculate their average centroid velocities, which are found to rarely exceed 3 km/s. In addition, we give rough estimates of mass and gravitational energy for every detected prominence and use these values to estimate the total mass and gravitational energy of all simultaneously existing prominences (1012 - 1014 kg and 1029 - 1031 erg). Finally, we investigate the form of the gravitational energy spectrum of prominences and derive it to be a power-law of index -1.1 ± 0.2.

  10. Quiescent and Eruptive Prominences at Solar Minimum: A Statistical Study via an Automated Tracking System

    CERN Document Server

    Loboda, I P

    2015-01-01

    We employ an automated detection algorithm to perform a global study of solar prominence characteristics. We process four months of TESIS observations in the He II 304 A line taken close to the solar minimum of 2008-2009 and focus mainly on quiescent and quiescent-eruptive prominences. We detect a total of 389 individual features ranging from 25x25 to 150x500 Mm in size and obtain distributions of many their spatial characteristics, such as latitudinal position, height, size and shape. To study their dynamics, we classify prominences as either stable or eruptive and calculate their average centroid velocities, which are found to be rarely exceeding 3 km/s. Besides, we give rough estimates of mass and gravitational energy for every detected prominence and use these values to evaluate the total mass and gravitational energy of all simultaneously existing prominences (10e12-10e14 kg and 10e29-10e31 erg, respectively). Finally, we investigate the form of the gravitational energy spectrum of prominences and derive...

  11. Evidence for rotational motions in the feet of a quiescent solar prominence

    CERN Document Server

    Suárez, D Orozco; Bueno, J Trujillo

    2012-01-01

    We present observational evidence of apparent plasma rotational motions in the feet of a solar prominence. Our study is based on spectroscopic observations taken in the He I 1083.0 nm multiplet with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope. We recorded a time sequence of spectra with 34 s cadence placing the slit of the spectrograph almost parallel to the solar limb and crossing two feet of an intermediate size, quiescent hedgerow prominence. The data show opposite Doppler shifts, +/- 6 km/s, at the edges of the prominence feet. We argue that these shifts may be interpreted as prominence plasma rotating counterclockwise around the vertical axis to the solar surface as viewed from above. The evolution of the prominence seen in EUV images taken with the Solar Dynamic Observatory provided us clues to interpret the results as swirling motions. Moreover, time-distance images taken far from the central wavelength show plasma structures moving parallel to the solar limb with ve...

  12. Fine Magnetic Structure and Origin of Counter-Streaming Mass Flows in a Quiescent Solar Prominence

    CERN Document Server

    Shen, Yuandeng; Liu, Ying D; Chen, P F; Su, Jiangtao; Xu, Zhi; Liu, Zhong

    2015-01-01

    We present high-resolution observations of a quiescent solar prominence which was consisted of a vertical and a horizontal foot encircled by an overlying spine, and counter-streaming mass flows were ubiquitous in the prominence. While the horizontal foot and the spine were connecting to the solar surface, the vertical foot was suspended above the solar surface and supported by a semicircular bubble structure. The bubble first collapsed and then reformed at a similar height, finally, it started to oscillate for a long time. We find that the collapsing and oscillation of the bubble boundary were tightly associated with a flare-like feature located at the bottom of the bubble. Based on the observational results, we propose that the prominence should be composed of an overlying horizontal spine encircling a low-lying horizontal and a vertical foot, in which the horizontal foot was consisted of shorter field lines running partially along the spine and with the both ends connecting to the solar surface, while the v...

  13. FINE MAGNETIC STRUCTURE AND ORIGIN OF COUNTER-STREAMING MASS FLOWS IN A QUIESCENT SOLAR PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yuandeng; Liu, Yu; Xu, Zhi; Liu, Zhong [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650216 (China); Liu, Ying D. [State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China); Chen, P. F. [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China); Su, Jiangtao, E-mail: ydshen@ynao.ac.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2015-11-20

    We present high-resolution observations of a quiescent solar prominence that consists of a vertical and a horizontal foot encircled by an overlying spine and has ubiquitous counter-streaming mass flows. While the horizontal foot and the spine were connected to the solar surface, the vertical foot was suspended above the solar surface and was supported by a semicircular bubble structure. The bubble first collapsed, then reformed at a similar height, and finally started to oscillate for a long time. We find that the collapse and oscillation of the bubble boundary were tightly associated with a flare-like feature located at the bottom of the bubble. Based on the observational results, we propose that the prominence should be composed of an overlying horizontal spine encircling a low-lying horizontal and vertical foot, in which the horizontal foot consists of shorter field lines running partially along the spine and has ends connected to the solar surface, while the vertical foot consists of piling-up dips due to the sagging of the spine fields and is supported by a bipolar magnetic system formed by parasitic polarities (i.e., the bubble). The upflows in the vertical foot were possibly caused by the magnetic reconnection at the separator between the bubble and the overlying dips, which intruded into the persistent downflow field and formed the picture of counter-streaming mass flows. In addition, the counter-streaming flows in the horizontal foot were possibly caused by the imbalanced pressure at the both ends.

  14. Fine structure and Alfven string-mode oscillations of a quiescent prominence

    Science.gov (United States)

    Petrov, Nicola; Duchlev, Peter; Rompolt, Bogdan; Rudawy, Pawel

    Series of Hα spectra and slit-jaw Hα filtergrams of a quiescent prominence taken at Pic du Midi Observatory on November 7, 1977, are studied. The image processing of the Hα filtergrams reveals an internal structure of the prominence consisting of several arches. Series of high-resolution Hα spectra obtained with the slit position located on a selected part of one of the prominence arches have been chosen for Doppler shift analysis. We got a good correspondence between the prominence structural elements identified in the Hα filtergrams and the corresponding spectral cuts. The prominence arch shows cyclic displacement along the line-of-sight direction implying Alfvén string-mode oscillations.

  15. Measurements of H-beta, He D3, and Ca/+/ 8542-A line emission in quiescent prominences

    Science.gov (United States)

    Landman, D. A.; Edberg, S. J.; Laney, C. D.

    1977-01-01

    Measurements of H-beta, He D3, and Ca(+) 8542-A line emission in 18 quiescent prominences are presented which were performed with a 25-cm coronagraph/coude spectrograph system and an optical multichannel analyzer utilizing a Si-vidicon detector assembly mounted at the single-pass spectrograph port. The data obtained show that the line profiles deviate in the wings from those calculated on the basis of an isothermal atmosphere and a Gaussian absorption coefficient. Both a non-Gaussian microturbulence component and a temperature gradient from prominence-core to coronal values can successfully account for this phenomenon. The line widths from a given line of sight of prominence material are reduced on the basis of a common core emitting region with a temperature of 7500 to 11,600 K and a microturbulent velocity of 4.5 to 7.1 km/s for the isothermal model (these values are 5% to 10% less for the two-temperature model). It is noted that long-period low-amplitude oscillations in the D3 line width and intensity were observed when a specific line of sight in a quiescent prominence was followed. These oscillations are found to remain coherent for as many as 3 or 4 cycles and to be associated with prominence structural activation.

  16. Testing MHD models of prominences and flares with observations of solar plasma electric fields

    Science.gov (United States)

    Foukal, Peter V.; Behr, Bradford B.

    1995-02-01

    We present measurements of electric fields in quiescent prominences and in a small flare surge, obtained with CRI electrograph at the NSO/SP 40 cm coronagraph, in 1993 and 1994. Our results on the 9 brightest quiescent prominences enable us to place r.m.s. upper limits of Et less than 2 - 5 V/cm on the component of E transverse to the line of sight. We show that these upper limits may be difficult to reconcile with non-ideal MHD models of quiescent prominences formed in extended neutral sheets, whethere or not the tearing mode instability is present. They do, however, seem consistent with ideal MHD models of prominence support. We point out also that these upper limits are within a factor 4 of the minimum value of anistropic electric field that exists due to motional Stark effect in any thermal plasma permeated by a directed magnetic field. Our data on the flare surge suggest and electric field of intensity E approximately 35 V/cm, oriented approximately parallel to the inferred magnetic field. This detection of Eparallel needs to be verified in other flares. But we note that a detectable Eparallel would not be expected in the current interruption flare mechanism, if only a single double layer is present. We show further that the observed relatively narrow, approximately-Gaussian, and only slightly Doppler-shifted Paschen lines, seem inconsistent with the multiple double layers invoked in other models based on the current interruption mechanism. Our detection of Eparallel does seem consistent with reconnection (including tearing-mode) models of flares, provided the field-aligned electrical conductivity is anomalous over substantial volumes of the plasma circuit joining the reconnecting domain to the photosphere.

  17. Giant quiescent solar filament observed with high-resolution spectroscopy

    Science.gov (United States)

    Kuckein, C.; Verma, M.; Denker, C.

    2016-05-01

    Aims: An extremely large filament was studied in various layers of the solar atmosphere. The inferred physical parameters and the morphological aspects are compared with smaller quiescent filaments. Methods: A giant quiet-Sun filament was observed with the high-resolution Echelle spectrograph at the Vacuum Tower Telescope at Observatorio del Teide, Tenerife, Spain, on 2011 November 15. A mosaic of spectra (ten maps of 100″ × 182″) was recorded simultaneously in the chromospheric absorption lines Hα and Na i D2. Physical parameters of the filament plasma were derived using cloud model (CM) inversions and line core fits. The spectra were complemented with full-disk filtergrams (He i λ10830 Å, Hα, and Ca ii K) of the Chromospheric Telescope (ChroTel) and full-disk magnetograms of the Helioseismic and Magnetic Imager (HMI). Results: The filament had extremely large linear dimensions (~817 arcsec), which corresponds to about 658 Mm along a great circle on the solar surface. A total amount of 175119 Hα contrast profiles were inverted using the CM approach. The inferred mean line-of-sight (LOS) velocity, Doppler width, and source function were similar to previous works of smaller quiescent filaments. However, the derived optical thickness was higher. LOS velocity trends inferred from the Hα line core fits were in accord but weaker than those obtained with CM inversions. Signatures of counter-streaming flows were detected in the filament. The largest brightening conglomerates in the line core of Na i D2 coincided well with small-scale magnetic fields as seen by HMI. Mixed magnetic polarities were detected close to the ends of barbs. The computation of photospheric horizontal flows based on HMI magnetograms revealed flow kernels with a size of 5-8 Mm and velocities of 0.30-0.45 km s-1 at the ends of the filament. Conclusions: The physical properties of extremely large filaments are similar to their smaller counterparts, except for the optical thickness, which in

  18. Hinode and IRIS Observations of a Prominence-Cavity System

    Science.gov (United States)

    Jibben, Patricia R.; Reeves, Kathy; Su, Yingna

    2016-05-01

    Long-lived solar prominences often have a coronal cavity enclosing the prominence. Within the cavity, hot X-ray emission can persist above the prominence and in the central regions of the cavity. We present the results of an Interface Region Imaging Spectrograph (IRIS) and Hinode coordinated Observation Program (IHOP 264) study of a prominence-cavity system. The X-ray Telescope (XRT) observes an inflow of bright X-ray emission that strikes and envelops the prominence-cavity system causing an eruption of chromospheric plasma near the base of the prominence. During and after the eruption, an increase in X-ray emission forms within the cavity and above the prominence. IRIS and the EUV Imaging Spectrometer (EIS) observe strong blue shifts in both chromosphere and coronal lines during the eruption. The Solar Optical Telescope (SOT) Ca II H-line data show bright emission along the eruption path with complex turbulent plasma motions. The IRIS Si IV 1394 Angstrom spectra along the on-disk portion of the prominence show a region of decreased emission near the base of the prominence, suggesting a magnetic field bald-patch topology along the Polarity Inversion Line (PIL). Combined, these observations imply a cylindrical flux rope best represents the prominence-cavity system. A model of the magnetic structure of the prominence-cavity system comprised of a weakly twisted flux rope can explain the observed loops in the X-ray and EUV data. Observations from the Coronal Multichannel Polarimeter (CoMP) are compared to predicted models and are inconclusive. We find that more sensitive measurements of the magnetic field strength along the line-of-sight are needed to verify this configuration.Patricia Jibben and Kathy Reeves are supported by under contract 80111112705 from Lockheed-Martin to SAO, contract NNM07AB07C from NASA to SAO, grant number NNX12AI30G from NASA to SAO, and contract Z15-12504 from HAO to SAO under a grant from AFOSR. Yingna Su is supported by the Youth Fund of

  19. Synchronous observation of rising soluble bubble through quiescent solution

    Institute of Scientific and Technical Information of China (English)

    Yifu ZHANG; Shuai TIAN; Weizhong LI; Yongchen SONG

    2009-01-01

    An experimental method using computer image processing technology (CIPT) was proposed to observe and investigate the velocity, deformation, heat and mass transfer, etc. of a rising soluble gas (CO2) bubble through a quiescent hot water. A model was set up to describe the behavior of the bubble in a visual experi-mental system in which a high-speed camera rose instantaneously with the movement of the bubble. A series of trajectory videos about the bubble were recorded by a computer linked to the camera. The trajectory, volume changes and rate of mass transfer of the bubble were obtained by the CIPT. It is found that the single bubble follows a rolling trajectory at the initial stage when there is mass transfer. With the volume decreasing, the disturbed behavior of the bubble becomes tempered. When the rising velocity of the bubble reaches the maximum, the velocity is nearly at a constant. The experimental and analysis results show that this method is useful for the research on the mass transfer and the movement of rising bubbles in liquid.

  20. Observations of a Coronal Cavity and Prominence with Hinode, IRIS, and AIA

    Science.gov (United States)

    Jibben, Patricia R.; Reeves, Katharine

    2015-04-01

    Coronal cavities are low emission regions above quiescent prominences. The interaction of the prominence material and coronal cavity is still poorly understood. We present observations of a coronal cavity and prominence system observed on 9 October 2014. The observations are part of a joint observation program (HOP264) including Hinode and the Interface Region Imaging Spectrograph (IRIS). A small cavity is seen just above the prominence in the Hinode X-ray Telescope (XRT) images. Using data from the Solar Dynamic Observatory (SDO) Atmospheric Imaging Assembly (AIA), Hinode Solar Optical Telescope (SOT) and IRIS, multi-thermal plasma can be seen traveling along the cavity loops. During this time, a brightening is seen near the center of the cavity in the XRT images suggesting hot material has been trapped inside the cavity. In addition to presenting the cavity dynamics, we characterize the cavity velocity structures using the Hinode EUV Imaging Spectrometer (EIS) and discuss the magnetic structure of the cavity using data from the Coronal Multichannel Polarimeter (CoMP). This work is supported by under contract SP02H1701R from Lockheed-Martin to SAO, contract NNM07AB07C from NASA to SAO and grant number NNX12AI30G from NASA to SAO.

  1. The magnetic field configuration of a solar prominence inferred from spectropolarimetric observations in the He I 10830 A triplet

    CERN Document Server

    Suárez, David Orozco; Bueno, Javier Trujillo

    2014-01-01

    Context: The determination of the magnetic field vector in quiescent solar prominences is possible by interpreting the Hanle and Zeeman effects in spectral lines. However, observational measurements are scarce and lack high spatial resolution. Aims: To determine the magnetic field vector configuration along a quiescent solar prominence by interpreting spectropolarimetric measurements in the He I 1083.0 nm triplet obtained with the Tenerife Infrared Polarimeter installed at the German Vacuum Tower Telescope of the Observatorio del Teide. Methods. The He I 1083.0 nm triplet Stokes profiles are analyzed with an inversion code that takes into account the physics responsible of the polarization signals in this triplet. The results are put into a solar context with the help of extreme ultraviolet observations taken with the Solar Dynamic Observatory and the Solar Terrestrial Relations Observatory satellites. Results: For the most probable magnetic field vector configuration, the analysis depicts a mean field streng...

  2. Prominence and tornado dynamics observed with IRIS and THEMIS

    Science.gov (United States)

    Schmieder, Brigitte; Levens, Peter; Labrosse, Nicolas; Mein, Pierre; Lopez Ariste, Arturo; Zapior, Maciek

    2017-08-01

    Several prominences were observed during campaigns in September 2013 and July 2014 with the IRIS spectrometer and the vector magnetograph THEMIS (Tenerife). SDO/AIA and IRIS provided images and spectra of prominences and tornadoes corresponding to different physical conditions of the transition region between the cool plasma and the corona. The vector magnetic field was derived from THEMIS observations by using the He D3 depolarisation due to the magnetic field. The inversion code (PCA) takes into account the Hanle and Zeeman effects and allows us to compute the strength and the inclination of the magnetic field which is shown to be mostly horizontal in prominences as well as in tornadoes. Movies from SDO/AIA in 304 A and Hinode/SOT in Ca II show the highly dynamic nature of the fine structures. From spectra in Mg II and Si IV lines provided by IRIS and H-alpha observed by the Multi-channel Subtractive Double Pass (MSDP) spectrograph in the Meudon Solar Tower we derived the Doppler shifts of the fine structures and reconstructed the 3D structure of tornadoes. We conclude that the apparent rotation of AIA tornadoes is due to large-scale quasi-periodic oscillations of the plasma along more or less horizontal magnetic structures.

  3. Coordinated Observations of Prominences with SUMER/CDS and Ground Observatories

    Science.gov (United States)

    Wiik, J. E.; Schmieder, B.; Kucera, T.; Poland, A.

    An international campaign for the observation of prominences and filaments was successfully accomplished between June 3 and 9 1996. Several ground observatories took part in the campaign which included the space observatories SOHO and Yohkoh. The main objective of this campaign was to study the dynamics of prominences and the prominence-corona interface, the formation of filaments and the fine structures at different temperatures. We will reported on two Joint Observing Programmes of SUMER and CDS aboard SOHO (JOP 12 and JOP 17), which have been achieved. Finally we will present as an exemple a prominence observed on May 1, 1996 during the tests of the programme JOP 12. This prominence was associated with a CME (observed with LASCO). Very active parts with Dopplershifs up to +/- 36kms(-1) were measured in the SUMER spectra of the prominence, indicating the presence of twisted ropes during the eruption. Mean electron densities have spatial and temporal dispersion of one order of magnitude (10(9) - 10(10) cm(-3) ).

  4. Morphology Of A Hot Prominence Cavity Observed with Hinode/XRT and SDO/AIA

    Science.gov (United States)

    Weber, Mark A.; Reeves, K. K.; Gibson, S. E.; Kucera, T. A.

    2012-01-01

    Prominence cavities appear as circularly shaped voids in coronal emission over polarity inversion lines where a prominence channel is straddling the solar limb. The presence of chromospheric material suspended at coronal altitudes is a common but not necessary feature within these cavities. These voids are observed to change shape as a prominence feature rotates around the limb. We use a morphological model projected in cross-sections to fit the cavity emission in Hinode/XRT passbands, and then apply temperature diagnostics to XRT and SDO/AIA data to investigate the thermal structure. We find significant evidence that the prominence cavity is hotter than the corona immediately outside the cavity boundary. This investigation follows upon "Thermal Properties of A Solar Coronal Cavity Observed with the X-ray Telescope on Hinode" by Reeves et al., 2012, ApJ, in press.

  5. Observations and models of slow solar wind with Mg9+ ions in quiescent steamers

    CERN Document Server

    Ofman, Leon; Giordano, Silvio

    2012-01-01

    Quiescent streamers are characterized by a peculiar UV signature as pointed out by the results from the observations of the Ultraviolet and Coronograph Spectrometer (UVCS) on board SOHO: the intensity of heavy ion emission lines (such as OVI) show dimmer core relative to the edges. Previous models show that the structure of the heavy ion streamer emission relates to the acceleration regions of the slow solar wind at streamer legs and to gravitational settling processes in the streamer core. Observations of Mg9+ ion EUV emission in coronal streamers at solar minimum were first reported by the UVCS instrument. The Mg X 625A emission is an order of magnitude smaller than the OVI 1032A emission, requiring longer exposures to obtain statistically significant results. Here, MgX coronal observations are analyzed and compared, for the first time, with the solar minimum streamer structure in hydrogen and OVI emissions. We employ the 2.5D three-fluid model, developed previously to study the properties of O5+ ions in st...

  6. A giant quiescent solar filament observed with high-resolution spectroscopy

    CERN Document Server

    Kuckein, C; Denker, C

    2016-01-01

    A giant, quiet-Sun filament was observed with the high-resolution Echelle spectrograph at the Vacuum Tower Telescope at Observatorio del Teide on 2011 November 15. A mosaic of spectra (10 maps of 100" X 182") was recorded simultaneously in the chromospheric absorption lines H-alpha and Na I D2. Physical parameters of the filament plasma were derived using Cloud Model (CM) inversions and line core fits. The spectra were complemented with full-disk filtergrams (He I 10830 A, H-alpha, and Ca II K) of the Chromspheric Telescope (ChroTel) and full-disk magnetograms of HMI. The filament had extremely large linear dimensions (817"), which corresponds to about 658 Mm along a great circle on the solar surface. A total amount of 175119 H-alpha contrast profiles were inverted using the CM approach. The inferred mean line-of-sight (LOS) velocity, Doppler width, and source function were similar to previous works of smaller quiescent filaments. However, the derived optical thickness was larger. LOS velocity trends inferred...

  7. Subarcsecond Bright Points and Quasi-periodic Upflows Below a Quiescent Filament Observed by the IRIS

    CERN Document Server

    Li, Ting

    2016-01-01

    Using UV spectra and SJIs from the IRIS, and coronal images and magnetograms from the Solar Dynamics Observatory (SDO), we present the new features in a quiescent filament channel: subarcsecond bright points (BPs) and quasi-periodic upflows. The BPs in the TR have a spatial scale of about 350$-$580 km and lifetime of more than several tens of minutes. They are located at stronger magnetic structures in the filament channel, with magnetic flux of about 10$^{17}$$-$10$^{18}$ Mx. Quasi-periodic brightenings and upflows are observed in the BPs and the period is about 4$-$5 min. The BP and the associated jet-like upflow comprise a "tadpole-shaped" structure. The upflows move along bright filament threads and their directions are almost parallel to the spine of the filament. The upflows initiated from the BPs with opposite polarity magnetic fields have opposite directions. The velocity of the upflows in plane of sky is about 5$-$50 km s$^{-1}$. The emission line of Si IV 1402.77 {\\AA} at the locations of upflows ex...

  8. OBSERVATIONS OF LINEAR POLARIZATION IN A SOLAR CORONAL LOOP PROMINENCE SYSTEM OBSERVED NEAR 6173 Å

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Hilaire, Pascal; Martínez Oliveros, Juan-Carlos; Hudson, Hugh S.; Krucker, Säm; Bain, Hazel [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Schou, Jesper [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Couvidat, Sébastien, E-mail: shilaire@ssl.berkeley.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2014-05-10

    White-light observations by the Solar Dynamics Observatory's Helioseismic and Magnetic Imager of a loop-prominence system occurring in the aftermath of an X-class flare on 2013 May 13 near the eastern solar limb show a linearly polarized component, reaching up to ∼20% at an altitude of ∼33 Mm, about the maximum amount expected if the emission were due solely to Thomson scattering of photospheric light by the coronal material. The mass associated with the polarized component was 8.2 × 10{sup 14} g. At 15 Mm altitude, the brightest part of the loop was 3(±0.5)% linearly polarized, only about 20% of that expected from pure Thomson scattering, indicating the presence of an additional unpolarized component at wavelengths near Fe I (617.33 nm). We estimate the free electron density of the white-light loop system to possibly be as high as 1.8 × 10{sup 12} cm{sup –3}.

  9. FORMATION AND PLASMA CIRCULATION OF SOLAR PROMINENCES

    OpenAIRE

    Xia, Chun; Keppens, Rony

    2016-01-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous down flows in quiescent prominences are difficult to interpret as plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of pr...

  10. X-ray Observations of Coronal Rings Above Polar Crown Prominences

    Science.gov (United States)

    Jibben, Patricia R.

    2007-05-01

    Coronal rings have been observed over both north and south polar crown prominences with the X-ray Telescope aboard the Hinode Observatory. These rings appear as dark bands surrounded by the brighter diffuse corona and can only be seen suspended above the solar limb. The properties of these coronal rings will be presented as well as a review of current polar crown prominence models. The US XRT team is supported by a contract from NASA to SAO. Hinode is an international project supported by JAXA, NASA, PPARC and ESA. We are grateful to the Hinode team for all their efforts in the design, development and operation of the mission.

  11. Solar prominences

    CERN Document Server

    Engvold, Oddbjørn

    2015-01-01

    This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of promine...

  12. Multi-wavelength observations of PKS 2142–75 during active and quiescent gamma-ray states

    Energy Technology Data Exchange (ETDEWEB)

    Dutka, Michael S. [The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 (United States); Ojha, Roopesh [ORAU/NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States); Pottschmidt, Katja [Center for Research and Exploration in Space Science and Technology (CRESST), University of Maryland Baltimore Campus (UMBC) and NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States); Finke, Justin D. [Naval Research Laboratory, Space Science Division, Code 7653, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Stevens, Jamie [CSIRO Astronomy and Space Science, Locked Bag 194, Narrabri, NSW 2390 (Australia); Edwards, Philip G. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Blanchard, Jay [Departamento de Astronoma, Universidad de Concepción, Casilla 160 C, 4089100 Concepción (Chile); Lovell, James E. J. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, Tas 7001 (Australia); Nesci, Roberto [INAF/IAPS, via Fosso del Cavaliere 100, I-00133 Roma (Italy); Kadler, Matthias; Müller, Cornelia [Lehrstuhl für Astronomie, Universität Würzburg, Emil-Fischer-Straße 31, D-97074 Würzburg (Germany); Wilms, Joern; Krauss, Felicia [Remeis Observatory and ECAP, Sternwartstr. 7, D-96049 Bamberg (Germany); Tosti, Gino [University of Perugia, Piazza Università 1, I-06123 Perugia (Italy); Pursimo, Tapio [Nordic Optical Telescope, Apartado 474, E-38700 Santa Cruz de La Palma Santa Cruz de Tenerife (Spain); Gehrels, Neil, E-mail: ditko86@gmail.com [NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States)

    2013-12-20

    PKS 2142–75 (a.k.a. 2FGL J2147.4–7534) is a flat-spectrum radio quasar that was observed quasi-simultaneously by a suite of instruments across the electromagnetic spectrum during two flaring states in 2010 April and 2011 August as well as a quiescent state from 2011 December through 2012 January. The results of these campaigns and model spectral energy distributions (SEDs) from the active and quiescent states are presented. The SED model parameters of PKS 2142–75 indicate that the two flares of the source are created by unique physical conditions. SED studies of flat-spectrum radio quasars are beginning to indicate that there might be two types of flares, those that can be described purely by changes in the electron distribution and those that require changes in other parameters, such as the magnetic field strength or the size of the emitting region.

  13. Formation and plasma circulation of solar prominences

    CERN Document Server

    Xia, Chun

    2016-01-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous down flows in quiescent prominences are difficult to interpret as plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in-situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward dragging along mass-loaded field lines. The prominence plasma circulation is characterized by the dynamic balance between the drainage of prominence plasma back to the chromos...

  14. Direct Observations of Magnetic Reconnection Outflow and CME Triggering in a Small Erupting Solar Prominence

    CERN Document Server

    Reeves, Katharine K; Tian, Hui

    2015-01-01

    We examine a small prominence eruption that occurred on 2014 May 1 at 01:35 UT and was observed by the Interface Region Imaging Spectrometer (IRIS) and the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). Pre- and post-eruption images were taken by the X-Ray Telescope (XRT) on Hinode. Pre-eruption, a dome-like structure exists above the prominence, as demarcated by coronal rain. As the eruption progresses, we find evidence for reconnection between the prominence magnetic field and the overlying field. Fast flows are seen in AIA and IRIS, indicating reconnection outflows. Plane-of-sky flows of ~300 km s$^{-1}$ are observed in the AIA 171 A channel along a potentially reconnected field line. IRIS detects intermittent fast line-of-sight flows of ~200 km s$^{-1}$ coincident with the AIA flows. Differential emission measure calculations show heating at the origin of the fast flows. Post-eruption XRT images show hot loops probably due to reconfiguration of magnetic fields during the erupt...

  15. Observations of the surge-type Black Rapids Glacier, Alaska, during a quiescent period, 1970-92

    Science.gov (United States)

    Heinrichs, Thomas A.; Mayo, L.R.; Trabant, D.C.; March, R.S.

    1995-01-01

    This report presents 23 years (1970 to 1992) of observations of Black Rapids Glacier, Alaska. Black Rapids Glacier is a surge-type glacier which most recently surged in 1936-37, and is currently in its quiescent phase. This glacier is of special interest because it is a potential hazard to the trans-Alaska oil pipeline. Ten sites on the glacier were monitored from 1972 to 1987, and three sites were monitored from 1988 to 1992. The measurement program presented here includes observations of surface mass balance, ice velocity, and surface altitude made twice each year. Additional one-time data include observations of ice thickness, previously unreported observations of the 1936-37 surge, establishment of the geodetic control monuments, and a new map of Black Rapids Glacier.

  16. Helical motions of fine-structure prominence threads observed by Hinode and IRIS

    CERN Document Server

    Okamoto, Takenori J; Tsuneta, Saku

    2016-01-01

    Fine-structure dynamics in solar prominences holds critical clues to understanding their physical nature of significant space-weather implications. We report evidence of rotational motions of horizontal helical threads in two active-region prominences observed by the \\emph{Hinode} and/or \\emph{IRIS} satellites at high resolution. In the first event, we found transverse motions of brightening threads at speeds up to 55~km~s$^{-1}$ seen in the plane of the sky. Such motions appeared as sinusoidal space--time trajectories with a typical period of $\\sim$390~s, which is consistent with plane-of-sky projections of rotational motions. Phase delays at different locations suggest propagation of twists along the threads at phase speeds of 90--270~km~s$^{-1}$. At least 15 episodes of such motions occurred in two days, none associated with any eruption. For these episodes, the plane-of-sky speed is linearly correlated with the vertical travel distance, suggestive of a constant angular speed. In the second event, we found...

  17. An analytical model of prominence mass motion

    CERN Document Server

    Routh, Swati; Bhat, Atul

    2016-01-01

    Solar Prominences are intriguing, but poorly understood magnetic structures of the solar corona. Convective motions in the photosphere and sub-photosphere may be responsible for generating the magnetic fields that support long-lived quiescent solar prominence. The dynamics of solar prominence has been the subject of a large number of studies. We develop a theoretical model using analytical approximations to analyze the nature of the dynamics of these quiescent solar prominences based on the K-S model.

  18. Formation and Plasma Circulation of Solar Prominences

    Science.gov (United States)

    Xia, C.; Keppens, R.

    2016-05-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous downflows in quiescent prominences are difficult to interpret because plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward, dragging along mass-loaded field lines. The circulation of prominence plasma is characterized by the dynamic balance between the drainage of prominence plasma back to the chromosphere and the formation of prominence plasma via continuous condensation. Plasma evaporates from the chromosphere, condenses into the prominence in the corona, and drains back to the chromosphere, establishing a stable chromosphere-corona plasma cycle. Synthetic images of the modeled prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly closely resemble actual observations, with many dynamical threads underlying an elliptical coronal cavity.

  19. Internal Dynamics of a Twin-layer Solar Prominence

    Science.gov (United States)

    Xia, C.; Keppens, R.

    2016-07-01

    Modern observations revealed rich dynamics within solar prominences. The globally stable quiescent prominences, characterized by the presence of thin vertical threads and falling knobs, are frequently invaded by small rising dark plumes. These dynamic phenomena are related to magnetic Rayleigh-Taylor instability, since prominence matter, 100 times denser than surrounding coronal plasma, is lifted against gravity by weak magnetic field. To get a deeper understanding of the physics behind these phenomena, we use three-dimensional magnetohydrodynamic simulations to investigate the nonlinear magnetoconvective motions in a twin-layer prominence in a macroscopic model from chromospheric layers up to 30 Mm height. The properties of simulated falling “fingers” and uprising bubbles are consistent with those in observed vertical threads and rising plumes in quiescent prominences. Both sheets of the twin-layer prominence show a strongly coherent evolution due to their magnetic connectivity, and demonstrate collective kink deformation. Our model suggests that the vertical threads of the prominence as seen in an edge-on view, and the apparent horizontal threads of the filament when seen top-down are different appearances of the same structures. Synthetic images of the modeled twin-layer prominence reflect the strong degree of mixing established over the entire prominence structure, in agreement with the observations.

  20. Helioseismic and Magnetic Imager observations of linear polarization from a loop prominence system

    CERN Document Server

    Saint-Hilaire, Pascal; Oliveros, Juan-Carlos Martínez; Hudson, Hugh S; Krucker, Säm; Bain, Hazel; Couvidat, Sébastien

    2014-01-01

    White-light observations by the Solar Dynamics Observatory's Helioseismic and Magnetic Imager of a loop-prominence system occurring in the aftermath of an X-class flare on 2013 May 13 near the eastern solar limb show a linearly polarized component, reaching up to $\\sim$20% at an altitude of $\\sim$33 Mm, about the maximal amount expected if the emission were due solely to Thomson scattering of photospheric light by the coronal material. The mass associated with the polarized component was 8.2$\\times$10$^{14}$ g. At 15 Mm altitude, the brightest part of the loop was 3(+/-0.5)% linearly polarized, only about 20% of that expected from pure Thomson scattering, indicating the presence of an additional unpolarized component at wavelengths near Fe I (617.33 nm), probably thermal emission. We estimated the free electron density of the white-light loop system to possibly be as high as 1.8$\\times$10$^{12}$ cm$^{-3}$.

  1. Prominence and Filament Eruptions Observed by the Solar Dynamics Observatory: Statistical Properties, Kinematics, and Online Catalog

    CERN Document Server

    McCauley, Patrick I; Schanche, Nicole; Evans, Kaitlin E; Su, Chuan; McKillop, Sean; Reeves, Katharine K

    2015-01-01

    We present a statistical study of prominence and filament eruptions observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). Several properties are recorded for 904 events that were culled from the Heliophysics Event Knowledgebase (HEK) and incorporated into an online catalog for general use. These characteristics include the filament and eruption type, eruption symmetry and direction, apparent twisting and writhing motions, and the presence of vertical threads and coronal cavities. Associated flares and white-light coronal mass ejections (CME) are also recorded. Total rates are given for each property along with how they differ among filament types. We also examine the kinematics of 106 limb events to characterize the distinct slow- and fast-rise phases often exhibited by filament eruptions. The average fast-rise onset height, slow-rise duration, slow-rise velocity, maximum field-of-view (FOV) velocity, and maximum FOV acceleration are 83 Mm, 4.4 hours, 2.1 km/s, 106 km...

  2. Exploring the prominence-corona connection and its expansion into the outer corona using total solar eclipse observations

    Energy Technology Data Exchange (ETDEWEB)

    Habbal, Shadia Rifai [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Morgan, Huw [Institute of Mathematics, Physics and Computer Science, Aberystwyth University, Ceredigion, Cymru SY23 3BZ (United Kingdom); Druckmüller, Miloslav, E-mail: shadia@ifa.hawaii.edu [Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno (Czech Republic)

    2014-10-01

    Prominences constitute the most complex magnetic structures in the solar corona. The ubiquitous presence of their seemingly confined dense and cool plasma in an otherwise million-degree environment remains a puzzle. Using a decade of white light total solar eclipse observations, we show how these images reveal an intricate relationship between prominences and coronal structures both in their immediate vicinity, known as coronal cavities, and in the extended corona out to several solar radii. Observations of suspended prominences and twisted helical structures spanning several solar radii are central to these findings. The different manifestations of the prominence-corona interface that emerge from this study underscore the fundamental role played by prominences in defining and controlling the complex expansion and dynamic behavior of the solar magnetic field in the neighborhood of magnetic polarity reversal regions. This study suggests that the unraveling of prominences and the outward expansion of the helical twisted field lines linked to them could be the solar origin of twisted magnetic flux ropes detected in interplanetary space, and of the mechanism by which the Sun sheds its magnetic helicity. This work also underscores the likely role of the prominence-corona interface as a source of the slow solar wind.

  3. SDO and STEREO Observations of Prominence Dynamics During a Series of Eight Homologous Flares

    Science.gov (United States)

    Panesar, Navdeep K.; Innes, Davina E.; Sterling, Alphonse C.; Moore, Ronald L.

    2014-01-01

    Homologous flares are eruptive events that occur repetitively in the same active region, with similar structure and morphology. A series of at least eight homologous flares occurred in active region NOAA 11237 over 16 - 17 June 2011. A filament is rooted in the active region with an overlying coronal cavity. The active region appears on the southeast solar limb as seen from SDO/AIA, and on the disk as viewed from STEREO-B/EUVI; the dual perspective allows us to study in detail behavior of prominence/filament material entrained in the magnetic field of the repeatedly-erupting system. Each of the eruptions was mainly confined, with active-region prominence material being ejected from the core of the erupting region onto outer-lobe loops of the active region. The eruption series repeatedly disrupted material of a quiet-Sun extension of the prominence, and that material became suspended at progressively higher heights above the surface. Two final eruptions from the core region destabilized the field holding that material, instigating a coronal mass ejection (CME).

  4. Investigating prominence turbulence with Hinode SOT Dopplergrams

    CERN Document Server

    Hillier, Andrew; Ichimoto, Kiyoshi

    2016-01-01

    Quiescent prominences host a diverse range of flows, including Rayleigh-Taylor instability driven upflows and impulsive downflows, and so it is no surprise that turbulent motions also exist. As prominences are believed to have a mean horizontal guide field, investigating any turbulence they host could shed light on the nature of MHD turbulence in a wide range of astrophysical systems. In this paper we have investigated the nature of the turbulent prominence motions using structure function analysis on the velocity increments estimated from H$\\alpha$ Dopplergrams constructed with observational data from Hinode SOT. The pdf of the velocity increments shows that as we look at increasingly small spatial separations the distribution displays greater departure from a reference Gaussian distribution, hinting at intermittency in the velocity field. Analysis of the even order structure functions for both the horizontal and vertical separations showed the existence of two distinct regions displaying different exponents...

  5. Observational detection of drift velocity between ionized and neutral species in solar prominences

    CERN Document Server

    Khomenko, Elena; Diaz, Antonio J

    2016-01-01

    We report a detection of differences in ion and neutral velocities in prominences using high resolution spectral data obtained in September 2012 at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife). A time series of scans of a small portion of a solar prominence was obtained simultaneously with a high cadence using the lines of two elements with different ionization states, namely the CaII 8542 A and the HeI 10830 A. Displacements, widths and amplitudes of both lines were carefully compared to extract dynamical information about the plasma. Many dynamical features are detected, such as counterstreaming flows, jets and propagating waves. In all the cases we find very strong correlation between the parameters extracted from the lines of both elements, confirming that both trace the same plasma. Nevertheless, we also find short-lived transients where this correlation is lost. These transients are associated with the ion-neutral drift velocities of the order of several hundred m/s. The patches ...

  6. Observational Detection of Drift Velocity between Ionized and Neutral Species in Solar Prominences

    Science.gov (United States)

    Khomenko, Elena; Collados, Manuel; Díaz, Antonio J.

    2016-06-01

    We report the detection of differences in the ion and neutral velocities in prominences using high-resolution spectral data obtained in 2012 September at the German Vacuum Tower Telescope (Observatorio del Teide, Tenerife). A time series of scans of a small portion of a solar prominence was obtained simultaneously with high cadence using the lines of two elements with different ionization states, namely, Ca ii 8542 Å and He i 10830 Å. The displacements, widths, and amplitudes of both lines were carefully compared to extract dynamical information about the plasma. Many dynamical features are detected, such as counterstreaming flows, jets, and propagating waves. In all of the cases, we find a very strong correlation between the parameters extracted from the lines of both elements, confirming that both lines trace the same plasma. Nevertheless, we also find short-lived transients where this correlation is lost. These transients are associated with ion-neutral drift velocities of the order of several hundred m s-1. The patches of non-zero drift velocity show coherence in time-distance diagrams.

  7. Solar prominences

    Science.gov (United States)

    Schmieder, Brigitte; Aulanier, Guillaume; Török, Tibor

    2009-03-01

    Solar filaments (or prominences) are magnetic structures in the corona. They can be represented by twisted flux ropes in a bipolar magnetic environment. In such models, the dipped field lines of the flux rope carry the filament material and parasitic polarities in the filament channel are responsible for the existence of the lateral feet of prominences. Very simple laws do exist for the chirality of filaments, the so-called “filament chirality rules”: commonly dextral/sinistral filaments corresponding to left- (resp. right) hand magnetic twists are in the North/South hemisphere. Combining these rules with 3D weakly twisted flux tube models, the sign of the magnetic helicity in several filaments were identified. These rules were also applied to the 180° disambiguation of the direction of the photospheric transverse magnetic field around filaments using THEMIS vector magnetograph data (López Ariste et al. 2006). Consequently, an unprecedented evidence of horizontal magnetic support in filament feet has been observed, as predicted by former magnetostatic and recent MHD models. The second part of this review concerns the role of emerging flux in the vicinity of filament channels. It has been suggested that magnetic reconnection between the emerging flux and the pre-existing coronal field can trigger filament eruptions and CMEs. For a particular event, observed with Hinode/XRT, we observe signatures of such a reconnection, but no eruption of the filament. We present a 3D numerical simulation of emerging flux in the vicinity of a flux rope which was performed to reproduce this event and we briefly discuss, based on the simulation results, why the filament did not erupt.

  8. Measuring vector magnetic fields in solar prominences

    CERN Document Server

    Suárez, D Orozco; Bueno, J Trujillo

    2012-01-01

    We present spectropolarimetric observations in the He I 1083.0 nm multiplet of a quiescent, hedgerow solar prominence. The data were taken with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope at the Observatorio del Teide (Tenerife; Canary Islands; Spain). The observed He I circular and linear polarization signals are dominated by the Zeeman effect and by atomic level polarization and the Hanle effect, respectively. These observables are sensitive to the strength and orientation of the magnetic field vector at each spatial point of the field of view. We determine the magnetic field vector of the prominence by applying the HAZEL inversion code to the observed Stokes profiles. We briefly discuss the retrieved magnetic field vector configuration.

  9. First SDO/AIA Observation of Solar Prominence Formation Following an Eruption: Magnetic Dips and Sustained Condensation and Drainage

    CERN Document Server

    Liu, Wei; Low, B C

    2012-01-01

    Imaging solar coronal condensation forming prominences was difficult in the past, a situation recently changed by Hinode and SDO. We present the first example observed with SDO/AIA, in which material gradually cools through multiple EUV channels in a transequatorial loop system that confines an earlier eruption. Nine hours later, this leads to eventual condensation at the dip of these loops, forming a moderate-size prominence of ~$10^{14}$ gram, to be compared to the characteristic $10^{15}$ gram mass of a CME. The prominence mass is not static but maintained by condensation at a high estimated rate of $10^{10}$ gram/sec against a comparable, sustained drainage through numerous vertical downflow threads, such that 96% of the total condensation (~$10^{15}$ gram) is drained in approximately one day. The mass condensation and drainage rates temporally correlate with the total prominence mass. The downflow velocity has a narrow Gaussian distribution with a mean of 30 km/s, while the downward acceleration distribu...

  10. A solar tornado observed by AIA/SDO: Rotational flow and evolution of magnetic helicity in a prominence and cavity

    CERN Document Server

    Li, Xing; Leonard, Drew; Jeska, Lauren

    2012-01-01

    During 2011/09/24, as observed by the Atmospheric Imaging Assembly (AIA) instrument of the Solar Dynamic Observatory (SDO) and ground-based \\Ha\\ telescopes, a prominence and associated cavity appeared above the southwest limb. On 2011/09/25 8:00UT material flows upwards from the prominence core along a narrow loop-like structure, accompanied by a rise ($\\geq$50,000km) of the prominence core and the loop. As the loop fades by 10:00, small blobs and streaks of varying brightness rotate around the top part of the prominence and cavity, mimicking a cyclone. The most intense and coherent rotation lasts for over three hours, with emission in both hot ($\\sim$1MK) and cold (hydrogen and helium) lines. We suggest that the cyclonic appearance and overall evolution of the structure can be interpreted in terms of the expansion of helical structures into the cavity, and the movement of plasma along helical structures which appears as a rotation when viewed along the helix axis. The coordinated movement of material between...

  11. Estimation of Plasma Properties and Magnetic Field in a Prominence-like Structure as Observed by SDO/AIA

    CERN Document Server

    Dwivedi, Bhola N; Mohan, Anita

    2013-01-01

    We analyze a prominence-like cool plasma structure as observed by Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). We perform the Differential Emission Measure (DEM) analysis using various filters of AIA, and also deduce the temperature and density structure in and around the observed flux-tube. In addition to deducing plasma parameters, we also find an evidence of multiple harmonics of fast magnetoacoustic kink waves in the observed prominence-like magnetic structure. Making use of estimated plasma parameters and observed wave parameters, under the baseline of MHD seismology, we deduce magnetic field in the flux-tube. The wave period ratio P1/P2 = 2.18 is also observed in the flux-tube, which carries the signature of magnetic field divergence where we estimate the tube expansion factor as 1.27. We discuss constraints in the estimation of plasma and magnetic field properties in such a structure in the current observational perspective, which may shed new light on the localized ...

  12. Open questions on prominences from coordinated observations by IRIS, Hinode, SDO/AIA, THEMIS, and the Meudon/MSDP

    CERN Document Server

    Schmieder, Brigitte; Ariste, Arturo Lopez; Mein, Nicole; Mein, Pierre; Dalmasse, Kevin; Golub, Leon

    2014-01-01

    Context. A large prominence was observed on September 24, 2013, for three hours (12:12 UT -15:12 UT) with the newly launched (June 2013) Interface Region Imaging Spectrograph (IRIS), THEMIS (Tenerife), the Hinode Solar Optical Telescope (SOT), the Solar Dynamic Observatory Atmospheric Imaging Assembly (SDO/AIA), and the Multichannel Subtractive Double Pass spectrograph (MSDP) in the Meudon Solar Tower. Aims. The aim of this work is to study the dynamics of the prominence fine structures in multiple wavelengths to understand their formation. Methods. The spectrographs IRIS and MSDP provided line profiles with a high cadence in Mg II and in Halpha lines. Results. The magnetic field is found to be globally horizontal with a relatively weak field strength (8-15 Gauss). The Ca II movie reveals turbulent-like motion that is not organized in specific parts of the prominence. On the other hand, the Mg II line profiles show multiple peaks well separated in wavelength. Each peak corresponds to a Gaussian profile, and n...

  13. A first look into the magnetic field configuration of prominence threads using spectropolarimetric data

    CERN Document Server

    Suarez, D Orozco; Bueno, J Trujillo

    2013-01-01

    We show preliminary results of an ongoing investigation aimed at determining the configuration of the magnetic field vector in the threads of a quiescent hedgerow solar prominence using high-spatial resolution spectropolarimetric observations taken in the He I 1083.0 nm multiplet. The data consist of a two-dimensional map of a quiescent hedgerow prominence showing vertical threads. The observations were obtained with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope at the Observatorio del Teide (Spain). The He I 1083.0 nm Stokes signals are interpreted with an inversion code, which takes into account the key physical processes that generate and/or modify circular and linear polarization signals in the He I 1083.0 nm triplet: the Zeeman effect, anisotropic radiation pumping, and the Hanle effect. We present initial results of the inversions, i.e, the strength and orientation of the magnetic field vector along the prominence and in prominence threads.

  14. DETERMINATION OF PROMINENCE PLASMA {beta} FROM THE DYNAMICS OF RISING PLUMES

    Energy Technology Data Exchange (ETDEWEB)

    Hillier, Andrew [Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan); Hillier, Richard [Department of Aeronautics, Imperial College, London (United Kingdom); Tripathi, Durgesh, E-mail: andrew@kwasan.kyoto-u.ac.jp [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India)

    2012-12-20

    Observations by the Hinode satellite show in great detail the dynamics of rising plumes, dark in chromospheric lines, in quiescent prominences that propagate from large ({approx}10 Mm) bubbles that form at the base of the prominences. These plumes present a very interesting opportunity to study magnetohydrodynamic (MHD) phenomena in quiescent prominences, but obstacles still remain. One of the biggest issues is that of the magnetic field strength, which is not easily measurable in prominences. In this paper we present a method that may be used to determine a prominence's plasma {beta} when rising plumes are observed. Using the classic fluid dynamic solution for flow around a circular cylinder with an MHD correction, the compression of the prominence material can be estimated. This has been successfully confirmed through simulations; application to a prominence gave an estimate of the plasma {beta} as {beta} = 0.47 {+-} 0.079 to 1.13 {+-} 0.080 for the range {gamma} = 1.4-1.7. Using this method it may be possible to estimate the plasma {beta} of observed prominences, therefore helping our understanding of a prominence's dynamics in terms of MHD phenomena.

  15. Multiband Observations of the Quasar PKS 2326–502 during Active and Quiescent Gamma-Ray States in 2010–2012

    Science.gov (United States)

    Dutka, Michael S.; Carpenter, Bryce D.; Ojha, Roopesh; Finke, Justin D.; D’Ammando, Filippo; Kadler, Matthias; Edwards, Philip G.; Stevens, Jamie; Torresi, Eleonora; Grandi, Paola; Nesci, Roberto; Krauß, Felicia; Müller, Cornelia; Wilms, Joern; Gehrels, Neil

    2017-02-01

    Quasi-simultaneous observations of the Flat Spectrum Radio Quasar PKS 2326‑502 were carried out in the γ-ray, X-ray, UV, optical, near-infrared, and radio bands. Using these observations, we are able to characterize the spectral energy distribution (SED) of the source during two flaring and one quiescent γ-ray states. These data were used to constrain one-zone leptonic models of the SEDs of each flare and investigate the physical conditions giving rise to them. While modeling one flare required only changes in the electron spectrum compared to the quiescent state, modeling the other flare required changes in both the electron spectrum and the size of the emitting region. These results are consistent with an emerging pattern of two broad classes of flaring states seen in blazars. Type 1 flares are explained by changes solely in the electron distribution, whereas type 2 flares require a change in an additional parameter. This suggests that different flares, even in the same source, may result from different physical conditions or different regions in the jet.

  16. FIRST SIMULTANEOUS OBSERVATION OF AN H{alpha} MORETON WAVE, EUV WAVE, AND FILAMENT/PROMINENCE OSCILLATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Asai, Ayumi; Isobe, Hiroaki [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Ishii, Takako T.; Kitai, Reizaburo; Ichimoto, Kiyoshi; UeNo, Satoru; Nagata, Shin' ichi; Morita, Satoshi; Nishida, Keisuke; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shiota, Daikou [Advanced Science Institute, RIKEN, Wako, Saitama 351-0198 (Japan); Oi, Akihito [College of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Akioka, Maki, E-mail: asai@kwasan.kyoto-u.ac.jp [Hiraiso Solar Observatory, National Institute of Information and Communications Technology, Hitachinaka, Ibaraki 311-1202 (Japan)

    2012-02-15

    We report on the first simultaneous observation of an H{alpha} Moreton wave, the corresponding EUV fast coronal waves, and a slow and bright EUV wave (typical EIT wave). We observed a Moreton wave, associated with an X6.9 flare that occurred on 2011 August 9 at the active region NOAA 11263, in the H{alpha} images taken by the Solar Magnetic Activity Research Telescope at Hida Observatory of Kyoto University. In the EUV images obtained by the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory we found not only the corresponding EUV fast 'bright' coronal wave, but also the EUV fast 'faint' wave that is not associated with the H{alpha} Moreton wave. We also found a slow EUV wave, which corresponds to a typical EIT wave. Furthermore, we observed, for the first time, the oscillations of a prominence and a filament, simultaneously, both in the H{alpha} and EUV images. To trigger the oscillations by the flare-associated coronal disturbance, we expect a coronal wave as fast as the fast-mode MHD wave with the velocity of about 570-800 km s{sup -1}. These velocities are consistent with those of the observed Moreton wave and the EUV fast coronal wave.

  17. Model comparison for the density structure along solar prominence threads

    CERN Document Server

    Arregui, I

    2015-01-01

    Quiescent solar prominence fine structures are typically modelled as density enhancements, called threads, which occupy a fraction of a longer magnetic flux tube. The profile of the mass density along the magnetic field is however unknown and several arbitrary alternatives are employed in prominence wave studies. We present a comparison of theoretical models for the field-aligned density along prominence fine structures. We consider Lorentzian, Gaussian, and parabolic profiles. We compare their theoretical predictions for the period ratio between the fundamental transverse kink mode and the first overtone to obtain estimates for the ratio of densities between the central part of the tube and its foot-points and to assess which one would better explain observed period ratio data. Bayesian parameter inference and model comparison techniques are developed and applied. Parameter inference requires the computation of the posterior distribution for the density gradient parameter conditional on the observable period...

  18. Pre-flare Coronal Jet and Evolutionary Phases of a Solar Eruptive Prominence Associated with the M1.8 Flare: SDO and RHESSI Observations

    Science.gov (United States)

    Joshi, Bhuwan; Kushwaha, Upendra; Veronig, Astrid M.; Cho, K.-S.

    2016-12-01

    We investigate the triggering, activation, and ejection of a solar eruptive prominence that occurred in a multi-polar flux system of active region NOAA 11548 on 2012 August 18 by analyzing data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, the Reuven Ramaty High Energy Solar Spectroscopic Imager, and the Extreme Ultraviolet Imager/Sun Earth Connection Coronal and Heliospheric Investigation on board the Solar Terrestrial Relation Observatory. Prior to the prominence activation, we observed striking coronal activities in the form of a blowout jet, which is associated with the rapid eruption of a cool flux rope. Furthermore, the jet-associated flux rope eruption underwent splitting and rotation during its outward expansion. These coronal activities are followed by the prominence activation during which it slowly rises with a speed of ˜12 km s-1 while the region below the prominence emits gradually varying EUV and thermal X-ray emissions. From these observations, we propose that the prominence eruption is a complex, multi-step phenomenon in which a combination of internal (tether-cutting reconnection) and external (i.e., pre-eruption coronal activities) processes are involved. The prominence underwent catastrophic loss of equilibrium with the onset of the impulsive phase of an M1.8 flare, suggesting large-scale energy release by coronal magnetic reconnection. We obtained signatures of particle acceleration in the form of power-law spectra with hard electron spectral index (δ ˜ 3) and strong HXR footpoint sources. During the impulsive phase, a hot EUV plasmoid was observed below the apex of the erupting prominence that ejected in the direction of the prominence with a speed of ˜177 km s-1. The temporal, spatial, and kinematic correlations between the erupting prominence and the plasmoid imply that the magnetic reconnection supported the fast ejection of prominence in the lower corona.

  19. Formation and evolution of a multi-threaded prominence

    CERN Document Server

    Luna, M; DeVore, C R

    2012-01-01

    We investigate the process of formation and subsequent evolution of prominence plasma in a filament channel and its overlying arcade. We construct a three-dimensional time-dependent model of an intermediate quiescent prominence. We combine the magnetic field structure with one-dimensional independent simulations of many flux tubes, of a three-dimensional sheared double arcade, in which the thermal nonequilibrium process governs the plasma evolution. We have found that the condensations in the corona can be divided into two populations: threads and blobs. Threads are massive condensations that linger in the field line dips. Blobs are ubiquitous small condensations that are produced throughout the filament and overlying arcade magnetic structure, and rapidly fall to the chromosphere. The threads are the principal contributors to the total mass. The total prominence mass is in agreement with observations, assuming a reasonable filling factor. The motion of the threads is basically horizontal, while blobs move in...

  20. Non-thermal line-broadening in solar prominence

    CERN Document Server

    Stellmacher, Goetz

    2016-01-01

    We show that the line broadening in quiescent solar prominences is mainly due to non-thermal velocities. We have simultaneously observed a wide range of optically thin lines in quiescent prominences, selected for bright and narrow Mg\\,b emission without line satellites from macro-shifts. We find a ratio of reduced widths of H-gamma and H-delta of 1.05 +-0.03 which can hardly be attributed to saturation, since both are optically thin for the prominences observed: tau(gamma)<0.3 ; tau(delta)<0.15. We confirm the ratio of reduced widths of He4772(triplet) and He5015(singlet of 1.1 +-0.05 at higher significance and detect a width ratio of Mgb2 and Mg4571 (both from the triplet system) of 1.3 +-0.1. The discrepant widths of lines from different atoms, and even from the same atom, cannot be represented by a unique pair [T_kin ; V_nth]. Values of T_kin deduced from observed line radiance using models, indicate low temperatures down to T_kin~5000K. Non-thermal velocities, related to different physical states of...

  1. Parker Lecture - Prominences: the key to understanding solar activity

    Science.gov (United States)

    Karpen, Judith T.

    2011-05-01

    Prominences are spectacular manifestations of both quiescent and eruptive solar activity. The largest examples can be seen with the naked eye during eclipses, making prominences among the first solar features to be described and catalogued. Steady improvements in temporal and spatial resolution from both ground- and space-based instruments have led us to recognize how complex and dynamic these majestic structures really are. Their distinguishing characteristics - cool knots and threads suspended in the hot corona, alignment along inversion lines in the photospheric magnetic field within highly sheared filament channels, and a tendency to disappear through eruption - offer vital clues as to their origin and dynamic evolution. Interpreting these clues has proven to be contentious, however, leading to fundamentally different models that address the basic questions: What is the magnetic structure supporting prominences, and how does so much cool, dense plasma appear in the corona? Despite centuries of increasingly detailed observations, the magnetic and plasma structures in prominences are poorly known. Routine measurements of the vector magnetic field in and around prominences have become possible only recently, while long-term monitoring of the underlying filament-channel formation process remains scarce. The process responsible for prominence mass is equally difficult to establish, although we have long known that the chromosphere is the only plausible source. As I will discuss, however, the motions and locations of prominence material can be used to trace the coronal field, thus defining the magnetic origins of solar eruptions. A combination of observations, theory, and numerical modeling must be used to determine whether any of the competing theories accurately represents the physics of prominences. I will discuss the criteria for a successful prominence model, compare the leading models, and present in detail one promising, comprehensive scenario for prominence

  2. SOLAR PROMINENCES: “DOUBLE, DOUBLE… BOIL AND BUBBLE”

    Energy Technology Data Exchange (ETDEWEB)

    Keppens, R.; Xia, C. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200 B, B-3001 Leuven (Belgium); Porth, O., E-mail: Rony.Keppens@wis.kuleuven.be [Department of Applied Mathematics, The University of Leeds, Leeds, LS2 9JT (United Kingdom)

    2015-06-10

    Observations revealed rich dynamics within prominences, the cool (10{sup 4} K), macroscopic (sizes of order 100 Mm) “clouds” in the million degree solar corona. Even quiescent prominences are continuously perturbed by hot, rising bubbles. Since prominence matter is hundredfold denser than coronal plasma, this bubbling is related to Rayleigh–Taylor instabilities. Here we report on true macroscopic simulations well into this bubbling phase, adopting an MHD description from chromospheric layers up to 30 Mm height. Our virtual prominences rapidly establish fully nonlinear (magneto)convective motions where hot bubbles interplay with falling pillars, with dynamical details including upwelling pillars forming within bubbles. Our simulations show impacting Rayleigh–Taylor fingers reflecting on transition region plasma, ensuring that cool, dense chromospheric material gets mixed with prominence matter up to very large heights. This offers an explanation for the return mass cycle mystery for prominence material. Synthetic views at extreme ultraviolet wavelengths show remarkable agreement with observations, with clear indications of shear-flow induced fragmentations.

  3. Observations of the gamma-ray emission from the Quiescent Sun with Fermi Large Area Telescope during the first 7 years in orbit

    Directory of Open Access Journals (Sweden)

    Rainó S.

    2017-01-01

    Full Text Available The high energy gamma-ray emission from the quiescent Sun is due to the interactions of cosmic ray (CR protons and electrons with matter and photons in the solar environment. Such interactions lead to two component gamma-ray emission: a disk-like emission due to the nuclear interactions of CR protons and nuclei in the solar atmosphere and a space extended emission due to the inverse Compton (IC scattering of CR electrons off solar photons in the whole heliosphere. The observation of these two solar emission components may give useful information about the evolution of the solar cycle by probing two different CR components (proton and electrons in regions not directly accessible by direct observations. We present the results of the observations of the Sun with Fermi-LAT in the first 7 years on orbit, with the exception of the flaring periods. Significantly large photon statistics and improved processing performance with respect to previous analysis allow us to explore both components of the emission in greater details and perform better comparisons of data with current models of the IC component. This allows us to probe CR electrons in the inner heliosphere which is not possible by other methods. Moreover, the longer period of observations allows us to study the variations of the emission between the maximum and the minimum of the solar cycle.

  4. Pre-flare coronal jet and evolutionary phases of a solar eruptive prominence associated with M1.8 flare: SDO and RHESSI observations

    CERN Document Server

    Joshi, Bhuwan; Veronig, Astrid; Cho, Kyung-Suk

    2016-01-01

    We investigate triggering, activation, and ejection of a solar eruptive prominence that occurred in a multi-polar flux system of active region NOAA 11548 on 2012 August 18 by analyzing data from AIA on board SDO, RHESSI, and EUVI/SECCHI on board STEREO. Prior to the prominence activation, we observed striking coronal activities in the form of a blowout jet which is associated with rapid eruption of a cool flux rope. Further, the jet-associated flux rope eruption underwent splitting and rotation during its outward expansion. These coronal activities are followed by the prominence activation during which it slowly rises with a speed of ~12 km/s while the region below the prominence emits gradually varying EUV and thermal X-ray emissions. From these observations, we propose that the prominence eruption is a complex, multi-step phenomenon in which a combination of internal (tether-cutting reconnection) and external (i.e., pre-eruption coronal activities) processes are involved. The prominence underwent catastroph...

  5. NuSTAR observations of the Dwarf Nova GK Persei in 2015: comparison between outburst and quiescent phases

    CERN Document Server

    Wada, Yuuki; Nakazawa, Kazuhiro; Makishima, Kazuo; Hayashi, Takayuki; Ishida, Manabu

    2016-01-01

    We report on NuSTAR observations of the Intermediate Polar GK Persei which also behaves as a Dwarf Nova. It exhibited a Dwarf Nova outburst in 2015 March-April. The object was observed in 3-79 keV X-rays with NuSTAR, once at the outburst peak, and again in 2015 September during quiescence. The 5-50 keV flux during the outburst was 26 times higher than that during the quiescence. With a multi-temperature emission model and a reflection model, we derived the post-shock temperature as 19.2 +/- 0.7 keV in the outburst, and 38.5 +4.1/-3.6 keV in the quiescence. This temperature difference is considered to reflect changes in the radius at which the accreting matter, forming an accretion disk, is captured by the magnetosphere of the white dwarf (WD). Assuming that this radius scales as the power of -2/7 of the mass accretion rate, and utilizing the two temperature measurements, as well as the standard mass-radius relation of WDs, we determined the WD mass in GK Persei as 0.90 +/- 0.06 solar masses. The magnetic fiel...

  6. Suzaku Observations of Luminous Quasars: Revealing the Nature of High-Energy Blazar Emission in Quiescent States

    CERN Document Server

    Abdo, A A; Sikora, M; Schady, P; Roming, P; Chester, M M; Maraschi, L

    2010-01-01

    We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243, PKS1127-145, PKS1510-089 and 3C 454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma-rays and the Swift UVOT in the UV and optical bands, respectively. We constructed their broad-band spectra covering the frequency range from 10^14 Hz up to 10^25 Hz, and those reveal the nature of high-energy emission of luminous blazars in their low-activity states. The analyzed X-ray spectra are well fitted by a power-law model with photoelectric absorption. In the case of PKS0208-512, PKS1127-145, and 3C 454.3, the X-ray continuum showed indication of hard-ening at low-energies. Moreover, when compared with the previous X-ray observations, we see a significantly increasing contribution of low-energy photons to the total X-ray fluxes when the sources are getting fainter. The same behavior can be noted in the Suzaku data al...

  7. ON THE SUPPORT OF SOLAR PROMINENCE MATERIAL BY THE DIPS OF A CORONAL FLUX TUBE

    Energy Technology Data Exchange (ETDEWEB)

    Hillier, Andrew [Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan); Van Ballegooijen, Adriaan [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2013-04-01

    The dense prominence material is believed to be supported against gravity through the magnetic tension of dipped coronal magnetic field. For quiescent prominences, which exhibit many gravity-driven flows, hydrodynamic forces are likely to play an important role in the determination of both the large- and small-scale magnetic field distributions. In this study, we present the first steps toward creating a three-dimensional magneto-hydrostatic prominence model where the prominence is formed in the dips of a coronal flux tube. Here 2.5D equilibria are created by adding mass to an initially force-free magnetic field, then performing a secondary magnetohydrodynamic relaxation. Two inverse polarity magnetic field configurations are studied in detail, a simple o-point configuration with a ratio of the horizontal field (B{sub x} ) to the axial field (B{sub y} ) of 1:2 and a more complex model that also has an x-point with a ratio of 1:11. The models show that support against gravity is either by total pressure or tension, with only tension support resembling observed quiescent prominences. The o-point of the coronal flux tube was pulled down by the prominence material, leading to compression of the magnetic field at the base of the prominence. Therefore, tension support comes from the small curvature of the compressed magnetic field at the bottom and the larger curvature of the stretched magnetic field at the top of the prominence. It was found that this method does not guarantee convergence to a prominence-like equilibrium in the case where an x-point exists below the prominence flux tube. The results imply that a plasma {beta} of {approx}0.1 is necessary to support prominences through magnetic tension.

  8. From MHD regime to quiescent non-inductive discharges in Tore Supra: experimental observations and MHD modelling

    Science.gov (United States)

    Maget, P.; Huysmans, G. T. A.; Lütjens, H.; Ottaviani, M.; Moreau, Ph; Ségui, J.-L.

    2009-06-01

    Attempts to run non-inductive plasma discharges on Tore Supra sometimes fail due to the triggering of magneto-hydro-dynamic (MHD) instabilities that saturate at a large amplitude, producing degraded confinement and loss of wave driven fast electrons (the so-called MHD regime (Maget et al 2005 Nucl. Fusion 45 69-80)). In this paper we investigate the transition to this soft (in the sense of non-disruptive) MHD limit from experimental observations, and compare it with non-linear code predictions. Such a comparison suggests that different non-linear regimes, with periodic relaxations or saturation, are correctly understood. However, successful non-inductive discharges without detectable magnetic island at q = 2 cannot be reproduced if realistic transport coefficients are used in the computation. Additional physics seems mandatory for explaining these discharges, such as diamagnetic effects, that could also justify cases of abrupt transition to the MHD regime.

  9. Hot prominence detected in the core of a coronal mass ejection: Analysis of SOHO/UVCS Lα and SOHO/LASCO visible-light observations

    Science.gov (United States)

    Heinzel, P.; Susino, R.; Jejčič, S.; Bemporad, A.; Anzer, U.

    2016-05-01

    Context. The paper deals with the physics of erupting prominences in the core of coronal mass ejections (CME). Aims: We determine the physical parameters of an erupting prominence embedded in the core of a CME using SOHO/UVCS hydrogen Lα and Lβ lines and SOHO/LASCO visible light observations. In particular we analyze the CME event observed on August 2, 2000. We develop the non-LTE (NLTE; i.e. considering departures from the local thermodynamic equilibrium - LTE) spectral diagnostics based on Lα and visible light observations. Methods: Our method is based on 1D NLTE modeling of eruptive prominences and takes into account the effect of large flow velocities, which reach up to 300 km s-1 for the studied event (the so-called Doppler dimming). The NLTE radiative-transfer method can be used for both optically thin and thick prominence structures. We combine spectroscopic UVCS observations of an erupting prominence in the core of a CME with visible light images from LASCO-C2 in order to derive the geometrical parameters like projected thickness and velocity, together with the effective temperature and column density of electrons. These are then used to constrain our NLTE radiative transfer modeling which provides the kinetic temperature, microturbulent velocity, gas pressure, ionization degree, the line opacities, and the prominence effective thickness (geometrical filling factor). Results: Analysis was made for 69 observational points (spatial pixels) inside the whole erupting prominence. Roughly one-half of them show a non-negligible Lα optical thickness for flow velocity 300 km s-1 and about one-third for flow velocity 150 km s-1. All pixels with Lατ0 ≤ 0.3 have been considered for further analysis, which is presented in the form of statistical distributions (histograms) of various physical quantities such as the kinetic temperature, gas pressure, and electron density for two representative flow velocities (150 and 300 km s-1) and non-zero microturbulence. For

  10. Spectroscopy of Solar Prominences Simultaneously from Space and Ground

    CERN Document Server

    Stellmacher, G; Dammasch, I E

    2013-01-01

    We present a comprehensive set of spectral data from two quiescent solar prominences observed in parallel from space and ground: with the VTT, simultaneous two-dimensional imaging of H-beta 4862 and Ca II 8542 yields a constant ratio, indicating small spatial pressure variations over the prominences. With the Gregory, simultaneous spectra of Ca II 8542 and He I 10830 were taken, their widths yielding 80006 *10^4 K; higher levels k > 8 appear more and more overpopulated. The larger widths of the Lyman lines require high non-thermal broadening close to that of 'hot' EUV lines. In contrast, the He II emission is more related to the 'cool' lines.

  11. Dynamics of a solar prominence tornado observed by SDO/AIA on 2012 November 7-8

    CERN Document Server

    Mghebrishvili, I; Kukhianidze, V; Ramishvili, G; Shergelashvili, B; Veronig, A; Poedts, S

    2015-01-01

    We study the detailed dynamics of a solar prominence tornado using time series of 171, 304, 193 and 211 {\\AA} spectral lines obtained by Solar Dynamics Observatory/ Atmospheric Imaging Assembly during 2012 November 7-8. The tornado first appeared at 08:00 UT, November 07, near the surface, gradually rose upwards with the mean speed of $\\sim$ 1.5 km s$^{-1}$ and persisted over 30 hr. Time-distance plots show two patterns of quasi-periodic transverse displacements of the tornado axis with periods of 40 and 50 minute at different phases of the tornado evolution. The first pattern occurred during the rising phase and can be explained by the upward motion of the twisted tornado. The second pattern occurred during the later stage of evolution when the tornado already stopped rising and could be caused either by MHD kink waves in the tornado or by the rotation of two tornado threads around a common axis. The later hypothesis is supported by the fact that the tornado sometimes showed a double structure during the qua...

  12. The role of Alfv\\'en wave heating in solar prominences

    CERN Document Server

    Soler, Roberto; Oliver, Ramon; Ballester, Jose Luis

    2016-01-01

    Observations have shown that magnetohydrodynamic waves over a large frequency range are ubiquitous in solar prominences. The waves are probably driven by photospheric motions and may transport energy up to prominences suspended in the corona. Dissipation of wave energy can lead to heating of the cool prominence plasma, so contributing to the local energy balance within the prominence. Here we discuss the role of Alfv\\'en wave dissipation as a heating mechanism for the prominence plasma. We consider a slab-like quiescent prominence model with a transverse magnetic field embedded in the solar corona. The prominence medium is modelled as a partially ionized plasma composed of a charged ion-electron single fluid and two separate neutral fluids corresponding to neutral hydrogen and neutral helium. Friction between the three fluids acts as a dissipative mechanism for the waves. The heating caused by externally-driven Alfv\\'en waves incident on the prominence slab is analytically explored. We find that the dense pro...

  13. First High-resolution Spectroscopic Observations of an Erupting Prominence Within a Coronal Mass Ejection by the Interface Region Imaging Spectrograph (IRIS)

    CERN Document Server

    Liu, Wei; Vial, Jean-Claude; Title, Alan M; Carlsson, Mats; Uitenbroek, Han; Okamoto, Takenori J; Berger, Thomas E; Antolin, Patrick

    2015-01-01

    Spectroscopic observations of prominence eruptions associated with coronal mass ejections (CMEs), although relatively rare, can provide valuable plasma and 3D geometry diagnostics. We report the first observations by the Interface Region Imaging Spectrograph (IRIS) mission of a spectacular fast CME/prominence eruption associated with an equivalent X1.6 flare on 2014 May 9. The maximum plane-of-sky and Doppler velocities of the eruption are 1200 and 460 km/s, respectively. There are two eruption components separated by ~200 km/s in Doppler velocity: a primary, bright component and a secondary, faint component, suggesting a hollow, rather than solid, cone-shaped distribution of material. The eruption involves a left-handed helical structure undergoing counter-clockwise (viewed top-down) unwinding motion. There is a temporal evolution from upward eruption to downward fallback with less-than-free-fall speeds and decreasing nonthermal line widths. We find a wide range of Mg II k/h line intensity ratios (less than ...

  14. Tornado-like Evolution of a Kink-unstable Solar Prominence

    Science.gov (United States)

    Wang, Wensi; Liu, Rui; Wang, Yuming

    2017-01-01

    We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The eastern section of the prominence first rose slowly, transforming into an arch-shaped structure as high as ˜150 Mm above the limb; the arch then writhed moderately in a left-handed sense, while the original dark prominence material emitted in the Fe ix 171 Å passband, and a braided structure appeared at the eastern edge of the warped arch. The unraveling of the braided structure was associated with a transient brightening in the EUV and apparently contributed to the formation of a curtain-like structure (CLS). The CLS consisted of myriad thread-like loops rotating counterclockwise about the vertical if viewed from above. Heated prominence material was observed to slide along these loops and land outside the filament channel. The tornado eventually disintegrated and the remaining material flew along a left-handed helical path constituting approximately a full turn, as corroborated through stereoscopic reconstruction, into the cavity of the stable, western section of the prominence. We suggest that the tornado-like evolution of the prominence was governed by the helical kink instability, and that the CLS formed through magnetic reconnections between the prominence field and the overlying coronal field.

  15. The Fate of Cool Material in the Hot Corona: Solar Prominences and Coronal Rain

    Science.gov (United States)

    Liu, Wei; Antolin, Patrick; Sun, Xudong; Vial, Jean-Claude; Berger, Thomas

    2017-08-01

    As an important chain of the chromosphere-corona mass cycle, some of the million-degree hot coronal mass undergoes a radiative cooling instability and condenses into material at chromospheric or transition-region temperatures in two distinct forms - prominences and coronal rain (some of which eventually falls back to the chromosphere). A quiescent prominence usually consists of numerous long-lasting, filamentary downflow threads, while coronal rain consists of transient mass blobs falling at comparably higher speeds along well-defined paths. It remains puzzling why such material of similar temperatures exhibit contrasting morphologies and behaviors. We report recent SDO/AIA and IRIS observations that suggest different magnetic environments being responsible for such distinctions. Specifically, in a hybrid prominence-coronal rain complex structure, we found that the prominence material is formed and resides near magnetic null points that favor the radiative cooling process and provide possibly a high plasma-beta environment suitable for the existence of meandering prominence threads. As the cool material descends, it turns into coronal rain tied onto low-lying coronal loops in a likely low-beta environment. Such structures resemble to certain extent the so-called coronal spiders or cloud prominences, but the observations reported here provide critical new insights. We will discuss the broad physical implications of these observations for fundamental questions, such as coronal heating and beyond (e.g., in astrophysical and/or laboratory plasma environments).

  16. FORMATION AND EVOLUTION OF A MULTI-THREADED SOLAR PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Luna, M. [CRESST and Space Weather Laboratory NASA/GSFC, Greenbelt, MD 20771 (United States); Karpen, J. T. [NASA/GSFC, Greenbelt, MD 20771 (United States); DeVore, C. R. [Naval Research Laboratory, Washington, DC 20375 (United States)

    2012-02-10

    We investigate the process of formation and subsequent evolution of prominence plasma in a filament channel and its overlying arcade. We construct a three-dimensional time-dependent model of an intermediate quiescent prominence suitable to be compared with observations. We combine the magnetic field structure of a three-dimensional sheared double arcade with one-dimensional independent simulations of many selected flux tubes, in which the thermal nonequilibrium process governs the plasma evolution. We have found that the condensations in the corona can be divided into two populations: threads and blobs. Threads are massive condensations that linger in the flux tube dips. Blobs are ubiquitous small condensations that are produced throughout the filament and overlying arcade magnetic structure, and rapidly fall to the chromosphere. The threads are the principal contributors to the total mass, whereas the blob contribution is small. The total prominence mass is in agreement with observations, assuming reasonable filling factors of order 0.001 and a fixed number of threads. The motion of the threads is basically horizontal, while blobs move in all directions along the field. We have generated synthetic images of the whole structure in an H{alpha} proxy and in two EUV channels of the Atmospheric Imaging Assembly instrument on board Solar Dynamics Observatory, thus showing the plasma at cool, warm, and hot temperatures. The predicted differential emission measure of our system agrees very well with observations in the temperature range log T = 4.6-5.7. We conclude that the sheared-arcade magnetic structure and plasma behavior driven by thermal nonequilibrium fit the abundant observational evidence well for typical intermediate prominences.

  17. Formation and Evolution of a Multi-threaded Solar Prominence

    Science.gov (United States)

    Luna, M.; Karpen, J. T.; DeVore, C. R.

    2012-02-01

    We investigate the process of formation and subsequent evolution of prominence plasma in a filament channel and its overlying arcade. We construct a three-dimensional time-dependent model of an intermediate quiescent prominence suitable to be compared with observations. We combine the magnetic field structure of a three-dimensional sheared double arcade with one-dimensional independent simulations of many selected flux tubes, in which the thermal nonequilibrium process governs the plasma evolution. We have found that the condensations in the corona can be divided into two populations: threads and blobs. Threads are massive condensations that linger in the flux tube dips. Blobs are ubiquitous small condensations that are produced throughout the filament and overlying arcade magnetic structure, and rapidly fall to the chromosphere. The threads are the principal contributors to the total mass, whereas the blob contribution is small. The total prominence mass is in agreement with observations, assuming reasonable filling factors of order 0.001 and a fixed number of threads. The motion of the threads is basically horizontal, while blobs move in all directions along the field. We have generated synthetic images of the whole structure in an Hα proxy and in two EUV channels of the Atmospheric Imaging Assembly instrument on board Solar Dynamics Observatory, thus showing the plasma at cool, warm, and hot temperatures. The predicted differential emission measure of our system agrees very well with observations in the temperature range log T = 4.6-5.7. We conclude that the sheared-arcade magnetic structure and plasma behavior driven by thermal nonequilibrium fit the abundant observational evidence well for typical intermediate prominences.

  18. Grammar and discourse prominence

    DEFF Research Database (Denmark)

    Christensen, Marie Herget; Kristensen, Line Burholt; Boye, Kasper

    in Danish, the lexicon-grammar contrast is a more important cue to discourse prominence (foreground vs. background status) than focalization (by means of focus particles). BOYE, K. & HARDER, P. 2012. A usage-based theory of grammatical status and grammaticalization. Language, 88, 1-44. RENSINK, R. A., O...

  19. Paying for prominence

    OpenAIRE

    Armstrong, Mark; Zhou, Jidong

    2011-01-01

    We investigate three ways in which firms can become "prominent" and thereby influence the order in which consumers consider options. First, firms can affect an intermediary's sales efforts by means of commission payments. When firms pay commission to a salesman, the salesman promotes the product with the highest commission, and steers ignorant consumers towards the more expensive product. Second, sellers can advertise prices on a price comparison website, so that consumers investigate the sui...

  20. LATE TIME MULTI-WAVELENGTH OBSERVATIONS OF SWIFT J1644+5734: A LUMINOUS OPTICAL/IR BUMP AND QUIESCENT X-RAY EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Levan, A. J.; Brown, G. C.; Lyman, J. D.; Stanway, E. R. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Tanvir, N. R.; Page, K. L.; O’Brien, P. T.; Wiersema, K. [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Metzger, B. D. [Columbia Astrophysics Laboratory, New York, NY 10027 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Fruchter, A. S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Bloom, J. S., E-mail: A.J.Levan@warwick.ac.uk [Astronomy Department, University of California, Berkeley, CA 94720-7450 (United States)

    2016-03-01

    We present late time multi-wavelength observations of Swift J1644+57, suggested to be a relativistic tidal disruption flare (TDF). Our observations extend to >4 years from discovery and show that 1.4 years after outburst the relativistic jet switched off on a timescale less than tens of days, corresponding to a power-law decay faster than t{sup −70}. Beyond this point weak X-rays continue to be detected at an approximately constant luminosity of L{sub X} ∼ 5 × 10{sup 42} erg s{sup −1} and are marginally inconsistent with a continuing decay of t{sup −5/3}, similar to that seen prior to the switch-off. Host photometry enables us to infer a black hole mass of M{sub BH} = 3 × 10{sup 6} M{sub ⊙}, consistent with the late time X-ray luminosity arising from sub-Eddington accretion onto the black hole in the form of either an unusually optically faint active galactic nucleus or a slowly varying phase of the transient. Optical/IR observations show a clear bump in the light curve at timescales of 30–50 days, with a peak magnitude (corrected for host galaxy extinction) of M{sub R} ∼ −22 to −23. The luminosity of the bump is significantly higher than seen in other, non-relativistic TDFs and does not match any re-brightening seen at X-ray or radio wavelengths. Its luminosity, light curve shape, and spectrum are broadly similar to those seen in superluminous supervnovae, although subject to large uncertainties in the correction of the significant host extinction. We discuss these observations in the context of both TDF and massive star origins for Swift J1644+5734 and other candidate relativistic tidal flares.

  1. Deep coronal hole associated with quiescent filament

    Science.gov (United States)

    Kesumaningrum, Rasdewita; Herdiwidjaya, Dhani

    2014-03-01

    We present a study of the morphology of quiescent filament observed by H-alpha Solar Telescope at Bosscha Observatory in association with coronal hole observed by Atmospheric Imaging Assembly (AIA) instrument in 193 Å from Solar Dynamics Observatory. H-alpha images were processed by imaging softwares, namely Iris 5.59 and ImageJ, to enhance the signal to noise ratio and to identify the filament features associated with coronal hole. For images observed on October 12, 2011, November 14, 2011 and January 2, 2012, we identified distinct features of coronal holes above the quiescent filaments. This associated coronal holes have filament-like morphology with a thick long thread as it's `spine', defined as Deep Coronal Hole. Because of strong magnetic field of sunspot, these filaments and coronal holes emerged far from active region and lasted for several days. It is interesting as for segmented filament, deep coronal holes above the filaments lasted for a quite long period of time and merged. This association between filament and deep coronal hole can be explained by filament magnetic loop.

  2. Model comparison for the density structure along solar prominence threads

    Science.gov (United States)

    Arregui, I.; Soler, R.

    2015-06-01

    Context. Quiescent solar prominence fine structures are typically modelled as density enhancements, called threads, which occupy a fraction of a longer magnetic flux tube. This is justified from the spatial distribution of the imaged plasma emission or absorption of prominences at small spatial scales. The profile of the mass density along the magnetic field is unknown, however, and several arbitrary alternatives are employed in prominence wave studies. The identification and measurement of period ratios from multiple harmonics in standing transverse thread oscillations offer a remote diagnostics method to probe the density variation of these structures. Aims: We present a comparison of theoretical models for the field-aligned density along prominence fine structures. They aim to imitate density distributions in which the plasma is more or less concentrated around the centre of the magnetic flux tube. We consider Lorentzian, Gaussian, and parabolic profiles. We compare theoretical predictions based on these profiles for the period ratio between the fundamental transverse kink mode and the first overtone to obtain estimates for the density ratios between the central part of the tube and its foot-points and to assess which one would better explain observed period ratio data. Methods: Bayesian parameter inference and model comparison techniques were developed and applied. To infer the parameters, we computed the posterior distribution for the density gradient parameter that depends on the observable period ratio. The model comparison involved computing the marginal likelihood as a function of the period ratio to obtain the plausibility of each density model as a function of the observable. We also computed the Bayes factors to quantify the relative evidence for each model, given a period ratio observation. Results: A Lorentzian density profile, with plasma density concentrated around the centre of the tube, seems to offer the most plausible inversion result. A

  3. Strongly absorbed quiescent X-ray emission from the X-ray transient XTE J0421+56 (CI Cam) observed with XMM-Newton

    CERN Document Server

    Boirin, L; Oosterbroek, T; Lumb, D H; Orlandini, M; Schartel, N

    2002-01-01

    We have observed the X-ray transient XTE J0421+56 in quiescence with XMM-Newton. The observed spectrum is highly unusual being dominated by an emission feature at ~6.5 keV. The spectrum can be fit using a partially covered power-law and Gaussian line model, in which the emission is almost completely covered (covering fraction of 0.98_{-0.06}^{+0.02}) by neutral material and is strongly absorbed with an N_H of (5_{-2}^{+3}) x 10^{23} atom cm^{-2}. This absorption is local and not interstellar. The Gaussian has a centroid energy of 6.4 +/- 0.1 keV, a width < 0.28 keV and an equivalent width of 940 ^{+650}_{-460} eV. It can be interpreted as fluorescent emission line from iron. Using this model and assuming XTE J0421+56 is at a distance of 5 kpc, its 0.5-10 keV luminosity is 3.5 x 10^{33} erg s^{-1}. The Optical Monitor onboard XMM-Newton indicates a V magnitude of 11.86 +/- 0.03. The spectra of X-ray transients in quiescence are normally modeled using advection dominated accretion flows, power-laws, or by th...

  4. TIME EVOLUTION OF PLASMA PARAMETERS DURING THE RISE OF A SOLAR PROMINENCE INSTABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Orozco Suárez, D.; Asensio Ramos, A.; Trujillo Bueno, J. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Díaz, A. J., E-mail: dorozco@iac.es [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

    2014-04-10

    We present high-spatial resolution spectropolarimetric observations of a quiescent hedgerow prominence taken in the He I 1083.0 nm triplet. The observation consisted of a time series in sit-and-stare mode of ∼36 minutes duration. The spectrograph's slit crossed the prominence body and we recorded the time evolution of individual vertical threads. Eventually, we observed the development of a dark Rayleigh-Taylor plume that propagated upward with a velocity, projected onto the plane of the sky, of 17 km s{sup –1}. Interestingly, the plume apex collided with the prominence threads pushing them aside. We inferred Doppler shifts, Doppler widths, and magnetic field strength variations by interpreting the He I Stokes profiles with the HAZEL code. The Doppler shifts show that clusters of threads move coherently while individual threads have oscillatory patterns. Regarding the plume we found strong redshifts (∼9-12 km s{sup –1}) and large Doppler widths (∼10 km s{sup –1}) at the plume apex when it passed through the prominence body and before it disintegrated. We associate the redshifts with perspective effects while the Doppler widths are more likely due to an increase in the local temperature. No local variations of the magnetic field strength associated with the passage of the plume were found; this leads us to conclude that the plumes are no more magnetized than the surroundings. Finally, we found that some of the threads' oscillations are locally damped, what allowed us to apply prominence seismology techniques to infer additional prominence physical parameters.

  5. Harvey Prize Lecture: The calm before the storm: the link between quiescent cavities and CMEs

    Science.gov (United States)

    Gibson, S. E.

    2005-05-01

    Coronal mass ejections (CMEs) are thought to be driven by magnetic energy, stored in twisted or sheared magnetic fields. Magnetic clouds, which are interplanetary manifestations of CMEs, are commonly modeled as flux ropes of twisted magnetic field. It has also become quite standard to model the erupting CME as a flux rope. However, the question of whether the flux rope is formed during the eruption, or whether the flux rope existed prior to the eruption, remains controversial. CMEs often possess a three-part morphology in white light observations of a bright front, followed by a relatively dark cavity, and lastly a bright core associated with an erupting prominence. The three-part structure of CMEs has been shown in a variety of models to be a consequence of a magnetic flux rope topology. The same physical reasons for the presence of the cavity system in eruption hold true in quiescence, and so it is significant that the three-part structure, in the form of helmet-streamer/cavity/prominence-core often exists quiescently in the corona. I will present an analysis of a few case studies of white light quiescent cavities as observed by the HAO Mauna Loa Solar Observatory Mk4 coronagraph. In particular I will consider the 3D structure and evolution of these cavities, and how these are related to CMEs. Finally, I will discuss the implications that these observations may have for the state of the corona just prior to a CME, and more generally for the nature of coronal MHD equilibria.

  6. INTEGRAL and BeppoSAX observations of the transient atoll source 4U 1608-522: from quiescent to hard spectral state

    CERN Document Server

    Tarana, Antonella; Ubertini, Pietro

    2008-01-01

    In this paper we report on the spectral evolution of 4U 1608-522 performed as part of the long Galactic Bulge monitoring with INTEGRAL. The data set include the April 2005 outburst. BeppoSAX archival data (two observations, in 1998 and 2000) have been also analysed and compared with the INTEGRAL ones. Three different spectral states have been identified from the hard Color-Intensity diagram derived from INTEGRAL: the canonical Hard and Soft as well as an Intermediate state. The hard state spectrum is well described by a weak black body component plus a Comptonised plasma component with high electron temperature (kTe~60 keV) extending up to 200 keV without any additional cut-off. The soft spectra are characterized by a cold Comptonised plasma (kTe= 2-3 keV, and 7 keV for the intermediate state) and a strong disk black body component. A reflection component, indicating reflection of the X-ray radiation from the accretion disc, is also present in the soft state revealed by BeppoSAX in 1998. The 2000 BeppoSAX obs...

  7. Tornado-Like Evolution of A Kink-Unstable Solar Prominence

    CERN Document Server

    Wang, Wensi; Wang, Yuming

    2016-01-01

    We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The eastern section of the prominence first rose slowly transforming into an arch-shaped structure as high as ~150 Mm above the limb; the arch then writhed moderately in a left-handed sense, while the originally dark prominence material became in emission in the Fe IX 171~{\\AA} passband, and a braided structure appeared at the eastern edge of the warped arch. The unraveling of the braided structure was associated with a transient brightening in EUV and apparently contributed to the formation of a curtain-like structure (CLS). The CLS consisted of myriads of thread-like loops rotating counterclockwise about the vertical if viewed from above. Heated prominence material was observed to slide along these loops and land outside the filament channel. The tornado was eventually disintegrated and the remaining material flew along a left-handed helical path of approximately a full turn, as corroborated through stereoscopic reconstruc...

  8. Compact Quiescent Galaxies at Intermediate Redshifts

    CERN Document Server

    Hsu, Li-Yen; Shih, Hsin-Yi

    2014-01-01

    From several searches of the area common to the Sloan Digital Sky Survey and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we have identified objects that have properties similar to those of the luminous quiescent compact galaxies found at z > 2. Here we present our results of 22 galaxies between z ~ 0.4 and z ~ 0.9 based on observations with the Keck I, Keck II and Subaru telescopes on Mauna Kea. By exploring sizes, morphologies, and stellar populations of these galaxies, we found that most of the galaxies we identified actually formed most of their stars at z 2 in the literature. Several of these young objects appear to be disk-like or possibly prolate. This lines up with several previous studies, which found that massive quiescent galaxies at high redshifts often have disk-like morphologies. If these galaxies were to be confirmed to be disks, their formation would be more likely caused by gas accretion than by major mergers. On the other hand, if these galaxies were to be confirmed to be...

  9. ERRATUM: Propagating Waves Transverse to the Magnetic Field in a Solar Prominence

    Science.gov (United States)

    Schmieder, B.; Kucera, T. A.; Knizhnik, K.; Luna, M.; Lopez-Ariste, A.; Toot, D.

    2014-01-01

    We report an unusual set of observations of waves in a large prominence pillar that consist of pulses propagating perpendicular to the prominence magnetic field. We observe a huge quiescent prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly in EUV on 2012 October 10 and only a part of it, the pillar, which is a foot or barb of the prominence, with the Hinode Solar Optical Telescope (SOT; in Ca II and Halpha lines), Sac Peak (in Ha, Hß, and Na-D lines), and THEMIS ("Télescope Héliographique pour l' Etude du Magnétisme et des Instabilités Solaires") with the MTR (MulTi-Raies) spectropolarimeter (in He D3 line). The THEMIS/MTR data indicates that the magnetic field in the pillar is essentially horizontal and the observations in the optical domain show a large number of horizontally aligned features on a much smaller scale than the pillar as a whole. The data are consistent with a model of cool prominence plasma trapped in the dips of horizontal field lines. The SOT and Sac Peak data over the four hour observing period show vertical oscillations appearing as wave pulses. These pulses, which include a Doppler signature, move vertically, perpendicular to the field direction, along thin quasi-vertical columns in the much broader pillar. The pulses have a velocity of propagation of about 10 km/s, a period of about 300 s, and a wavelength around 2000 km. We interpret these waves in terms of fast magnetosonic waves and discuss possible wave drivers.

  10. Prominence Mass Supply and the Cavity

    Science.gov (United States)

    Schmit, Donald J.; Gibson, S.; Luna, M.; Karpen, J.; Innes, D.

    2013-01-01

    A prevalent but untested paradigm is often used to describe the prominence-cavity system; the cavity is under-dense because it it evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolutin of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model and diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prminence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 A badpass near he prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  11. Solar Features - Prominences and Filaments

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Prominences and filaments are two manifestations of the same phenomenon. Both prominences and filaments are features formed above the chromosphere by cool dense...

  12. IMAGING PROMINENCE ERUPTIONS OUT TO 1 AU

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Brian E.; Howard, Russell A.; Linton, Mark G., E-mail: brian.wood@nrl.navy.mil [Naval Research Laboratory, Space Science Division, Washington, DC 20375 (United States)

    2016-01-10

    Views of two bright prominence eruptions trackable all the way to 1 AU are here presented, using the heliospheric imagers on the Solar TErrestrial RElations Observatory (STEREO) spacecraft. The two events first erupted from the Sun on 2011 June 7 and 2012 August 31, respectively. Only these two examples of clear prominence eruptions observable this far from the Sun could be found in the STEREO image database, emphasizing the rarity of prominence eruptions this persistently bright. For the 2011 June event, a time-dependent 3D reconstruction of the prominence structure is made using point-by-point triangulation. This is not possible for the August event due to a poor viewing geometry. Unlike the coronal mass ejection (CME) that accompanies it, the 2011 June prominence exhibits little deceleration from the Sun to 1 AU, as a consequence moving upwards within the CME. This demonstrates that prominences are not necessarily tied to the CME's magnetic structure far from the Sun. A mathematical framework is developed for describing the degree of self-similarity for the prominence's expansion away from the Sun. This analysis suggests only modest deviations from self-similar expansion, but close to the Sun the prominence expands radially somewhat more rapidly than self-similarity would predict.

  13. NONLINEAR MHD WAVES IN A PROMINENCE FOOT

    Energy Technology Data Exchange (ETDEWEB)

    Ofman, L. [Catholic University of America, Washington, DC 20064 (United States); Knizhnik, K.; Kucera, T. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Schmieder, B. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris-Diderot, Sorbonne Paris Cit, 5 place Jules Janssen, F-92195 Meudon (France)

    2015-11-10

    We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ∼ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5–11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5–14 G. For the typical prominence density the corresponding fast magnetosonic speed is ∼20 km s{sup −1}, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

  14. Topological Analyses of Symmetric Eruptive Prominences

    Science.gov (United States)

    Panasenco, O.; Martin, S. F.

    Erupting prominences (filaments) that we have analyzed from Hα Doppler data at Helio Research and from SOHO/EIT 304 Å, show strong coherency between their chirality, the direction of the vertical and lateral motions of the top of the prominences, and the directions of twisting of their legs. These coherent properties in erupting prominences occur in two patterns of opposite helicity; they constitute a form of dynamic chirality called the ``roll effect." Viewed from the positive network side as they erupt, many symmetrically-erupting dextral prominences develop rolling motion toward the observer along with right-hand helicity in the left leg and left-hand helicity in the right leg. Many symmetricaly-erupting sinistral prominences, also viewed from the positive network field side, have the opposite pattern: rolling motion at the top away from the observer, left-hand helical twist in the left leg, and right-hand twist in the right leg. We have analysed the motions seen in the famous movie of the ``Grand Daddy" erupting prominence and found that it has all the motions that define the roll effect. From our analyses of this and other symmetric erupting prominences, we show that the roll effect is an alternative to the popular hypothetical configuration of an eruptive prominence as a twisted flux rope or flux tube. Instead we find that a simple flat ribbon can be bent such that it reproduces nearly all of the observed forms. The flat ribbon is the most logical beginning topology because observed prominence spines already have this topology prior to eruption and an initial long magnetic ribbon with parallel, non-twisted threads, as a basic form, can be bent into many more and different geometrical forms than a flux rope.

  15. Ion-Neutral Coupling in Solar Prominences

    Science.gov (United States)

    Gilbert, Holly

    2011-01-01

    Interactions between ions and neutrals in a partially ionized plasma are important throughout heliophysics, including near the solar surface in prominences. Understanding how ion-neutral coupling affects formation, support, structure, and dynamics of prominences will advance our physical understanding of magnetized systems involving a transition from a weakly ionized dense gas to a fully ionized tenuous plasma. We address the fundamental physics of prominence support, which is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force, and the implications for observations. Because the prominence plasma is only partially ionized, it is necessary to consider the support of the both the ionized and neutral components. Support of the neutrals is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material.

  16. Using large galaxy surveys to distinguish z~0.5 quiescent galaxy models

    CERN Document Server

    Cohn, J D

    2013-01-01

    One of the most striking properties of galaxies is the bimodality in their star-formation rates. A major puzzle is why any given galaxy is star-forming or quiescent, and a wide range of physical mechanisms have been proposed as solutions. We consider how observations, such as might be available in upcoming large galaxy surveys, might distinguish different galaxy quenching scenarios. To do this, we combine an N-body simulation and multiple prescriptions from the literature to create several quiescent galaxy mock catalogues. Each prescription uses a different set of galaxy properties (such as history, environment, centrality) to assign individual simulation galaxies as quiescent. We find how and how much the resulting quiescent galaxy distributions differ from each other, both intrinsically and observationally. In addition to tracing observational consequences of different quenching mechanisms, our results indicate which sorts of quenching models might be most readily disentangled by upcoming observations and w...

  17. Properties of the prominence magnetic field and plasma distributions as obtained from 3D whole-prominence fine structure modeling

    Science.gov (United States)

    Gunár, S.; Mackay, D. H.

    2016-07-01

    Aims: We analyze distributions of the magnetic field strength and prominence plasma (temperature, pressure, plasma β, and mass) using the 3D whole-prominence fine structure model. Methods: The model combines a 3D magnetic field configuration of an entire prominence, obtained from non-linear force-free field simulations, with a detailed semi-empirically derived description of the prominence plasma. The plasma is located in magnetic dips in hydrostatic equilibrium and is distributed along multiple fine structures within the 3D magnetic model. Results: We show that in the modeled prominence, the variations of the magnetic field strength and its orientation are insignificant on scales comparable to the smallest dimensions of the observed prominence fine structures. We also show the ability of the 3D whole-prominence fine structure model to reveal the distribution of the prominence plasma with respect to its temperature within the prominence volume. This provides new insights into the composition of the prominence-corona transition region. We further demonstrate that the values of the plasma β are small throughout the majority of the modeled prominences when realistic photospheric magnetic flux distributions and prominence plasma parameters are assumed. While this is generally true, we also find that in the region with the deepest magnetic dips, the plasma β may increase towards unity. Finally, we show that the mass of the modeled prominence plasma is in good agreement with the mass of observed non-eruptive prominences.

  18. Imaging Prominence Eruptions Out to 1 AU

    CERN Document Server

    Wood, Brian E; Linton, Mark G

    2015-01-01

    Views of two bright prominence eruptions trackable all the way to 1AU are here presented, using the heliospheric imagers on the Solar TErrestrial RElations Observatory (STEREO) spacecraft. The two events first erupted from the Sun on 2011 June 7 and 2012 August 31, respectively. Only these two examples of clear prominence eruptions observable this far from the Sun could be found in the STEREO image database, emphasizing the rarity of prominence eruptions this persistently bright. For the 2011 June event, a time-dependent 3-D reconstruction of the prominence structure is made using point-by-point triangulation. This is not possible for the August event due to a poor viewing geometry. Unlike the coronal mass ejection (CME) that accompanies it, the 2011 June prominence exhibits little deceleration from the Sun to 1 AU, as a consequence moving upwards within the CME. This demonstrates that prominences are not necessarily tied to the CME's magnetic structure far from the Sun. A mathematical framework is developed ...

  19. Nonlinear MHD waves in a Prominence Foot

    CERN Document Server

    Ofman, Leon; Kucera, Therese; Schmieder, Brigitte

    2015-01-01

    We study nonlinear waves in a prominence foot using 2.5D MHD model motivated by recent high-resolution observations with Hinode/SOT in Ca~II emission of a prominence on October 10, 2012 showing highly dynamic small-scale motions in the prominence material. Observations of H$\\alpha$ intensities and of Doppler shifts show similar propagating fluctuations. However the optically thick nature of the emission lines inhibits unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity ($\\delta I/I\\sim \\delta n/n$). The waves are evident as significant density fluctuations that vary with height, and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with typical period in the range of 5-11 minutes, and wavelengths $\\sim <$2000 km. Recent Doppler shift observations show the transverse displacement of the propagating wav...

  20. Fine-Structured Plasma Flows in Prominences

    Science.gov (United States)

    Panasenco, O.; Velli, M.; Landi, S.

    2008-12-01

    Plasmas in prominences (filaments against the disk) exhibit a very wide spectrum of different kind of motions. Here we analyze the plasma motions inside prominences observed by Hinode/SOT during 2006-2007 with focus on two spectacular examples from 25 April 2007 in Halpha line and 30 November 2006 in CaH line and then carry out some simulations of the possible dynamics. Most filaments are composed of fine threads of similar dimensions rooted in the chromosphere/photosphere. Recent observations of counter-streaming motions together with oscillations along the threads provide strong evidence that the threads are field aligned. To more correctly interpret the nature of observed downward flows of dense and cool plasma as well as the upward dark flows of less dense plasma, we take into account the geometry of the prominence structures and the viewing angle. The dark upflows exhibit turbulent patterns such as vortex formation and shedding that are consistent with the motions predicted by instabilities of the interchange type. Sometimes an appearance of dark motions is generated by dark voids opened in the prominence sheet after initiation of nearby downflow streams, implying mass drainage in the downflows. Based on 304 A observations, there is more filament mass in prominences than is visible in either the Halpha or CaH lines. The source of the downward moving plasma may be located either higher above the visible upper edge of the prominence or on the far end of the prominence spine. The bright downward motions of the more cool and dense plasma may be partly due to the counter-streaming motion along the magnetic fields lines and also to the presence of Rayleigh-Taylor type or ballooning/interchange instabilities in the upper regions of the prominence. Transverse motions of filament threads caused by magnetic instabilities constantly provide the conditions for reconnection in the low part of the corona and the chromosphere. We suggest that the combination of flows along

  1. The "quiescent" black hole in M87

    CERN Document Server

    Reynolds, C S; Fabian, A C; Hwang, U; Canizares, C R

    1996-01-01

    It is believed that most giant elliptical galaxies possess nuclear black holes with masses in excess of $10^8\\Msun$. Bondi accretion from the interstellar medium might then be expected to produce quasar-like luminosities from the nuclei of even quiescent elliptical galaxies. It is a puzzle that such luminosities are not observed. Motivated by this problem, Fabian & Rees have recently suggested that the final stages of accretion in these objects occurs in an advection-dominated mode with a correspondingly small radiative efficiency. Despite possessing a long-known active nucleus and dynamical evidence for a black hole, the low radiative and kinetic luminosities of the core of M87 provide the best illustration of this problem. We examine an advection-dominated model for the nucleus of M87 and show that accretion at the Bondi rate is compatible with the best known estimates for the core flux from radio through to X-ray wavelengths. The success of this model prompts us to propose that FR-I radio galaxies and ...

  2. The formation of massive, quiescent galaxies at cosmic noon

    CERN Document Server

    Feldmann, Robert; Quataert, Eliot; Faucher-Giguere, Claude-Andre; Keres, Dusan

    2016-01-01

    The cosmic noon (z~1.5-3) marked a period of vigorous star formation for most galaxies. However, about a third of the more massive galaxies at those times were quiescent in the sense that their observed stellar populations are inconsistent with rapid star formation. The reduced star formation activity is often attributed to gaseous outflows driven by feedback from supermassive black holes, but the impact of black hole feedback on galaxies in the young Universe is not yet definitively established. We analyze the origin of quiescent galaxies with the help of ultra-high resolution, cosmological simulations that include feedback from stars but do not model the uncertain consequences of black hole feedback. We show that dark matter halos with specific accretion rates below ~0.25-0.4 per Gyr preferentially host galaxies with reduced star formation rates and red broad-band colors. The fraction of such halos in large dark matter only simulations matches the observed fraction of massive quiescent galaxies (~10^10-10^1...

  3. PROMINENCE VISIBILITY IN HINODE/XRT IMAGES

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, P. [Astronomical Institute of Slovak Academy of Sciences, 05960 Tatranská Lomnica (Slovakia); Jejčič, S. [University of Ljubljana, Faculty of Mathematics and Physics, 1000 Ljubljana (Slovenia); Heinzel, P. [Astronomical Institute, Czech Academy of Sciences, 25165 Ondřejov (Czech Republic); Anzer, U. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, D-85740 Garching (Germany); Jibben, P. R., E-mail: pschwartz@astro.sk [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-07-01

    In this paper we study the soft X-ray (SXR) signatures of one particular prominence. The X-ray observations used here were made by the Hinode/X-Ray Telescope instrument using two different filters. Both of them have a pronounced peak of the response function around 10 Å. One of them has a secondary smaller peak around 170 Å, which leads to a contamination of SXR images. The observed darkening in both of these filters has a very large vertical extension. The position and shape of the darkening correspond nicely with the prominence structure seen in SDO/AIA images. First, we have investigated the possibility that the darkening is caused by X-ray absorption. However, detailed calculations of the optical thickness in this spectral range show clearly that this effect is completely negligible. Therefore, the alternative is the presence of an extended region with a large emissivity deficit, which can be caused by the presence of cool prominence plasmas within an otherwise hot corona. To reproduce the observed darkening, one needs a very large extension along the line of sight of the region amounting to around 10{sup 5} km. We interpret this region as the prominence spine, which is also consistent with SDO/AIA observations in EUV.

  4. The soft quiescent spectrum of the transiently accreting 11-Hz X-ray pulsar in the globular cluster Terzan 5

    NARCIS (Netherlands)

    N. Degenaar; R. Wijnands

    2011-01-01

    We report on the quiescent X-ray properties of the recently discovered transiently accreting 11-Hz X-ray pulsar in the globular cluster Terzan 5. Using two archival Chandra observations, we demonstrate that the quiescent spectrum of this neutron star low-mass X-ray binary is soft and can be fit to a

  5. Time Variation of SiO Masers in VX Sagittarii over an Optically Quiescent Phase

    Science.gov (United States)

    Kamohara, Ryuichi; Deguchi, Shuji; Miyoshi, Makoto; Shen, Zhi-Qiang

    2005-04-01

    The time variation of SiO masers in a semi-regular variable, VX Sgr, was investigated in the period between 1994 and 2004 when the optical light curve exhibited an ˜6-yr quiescent phase intercepting a regularly pulsating era. The quiescent period occurred with a delay of several years after a decrease in the SiO maser flux. VLBA observations of SiO masers made during this period showed no drastic spatial variation except for emission features being shifted from south-west to north-east. The SiO maser flux decrease, and a succeeding optical quiescent phase, may indicate that the stellar mass-loss rate diminished over a few years around 1994. A SiO maser flare occurring in 1999 may be a reminiscence of a final gas blow, which resulted in the optically quiescent period.

  6. PROMINENCE ACTIVATION BY CORONAL FAST MODE SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Takuya [Department of Astronomy, Kyoto University, Sakyo, Kyoto, 606-8502 (Japan); Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shibata, Kazunari, E-mail: takahashi@kwasan.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2015-03-01

    An X5.4 class flare occurred in active region NOAA11429 on 2012 March 7. The flare was associated with a very fast coronal mass ejection (CME) with a velocity of over 2500 km s{sup −1}. In the images taken with the Solar Terrestrial Relations Observatory-B/COR1, a dome-like disturbance was seen to detach from an expanding CME bubble and propagated further. A Type-II radio burst was also observed at the same time. On the other hand, in extreme ultraviolet images obtained by the Solar Dynamic Observatory/Atmospheric Imaging Assembly (AIA), the expanding dome-like structure and its footprint propagating to the north were observed. The footprint propagated with an average speed of about 670 km s{sup −1} and hit a prominence located at the north pole and activated it. During the activation, the prominence was strongly brightened. On the basis of some observational evidence, we concluded that the footprint in AIA images and the ones in COR1 images are the same, that is, the MHD fast mode shock front. With the help of a linear theory, the fast mode Mach number of the coronal shock is estimated to be between 1.11 and 1.29 using the initial velocity of the activated prominence. Also, the plasma compression ratio of the shock is enhanced to be between 1.18 and 2.11 in the prominence material, which we consider to be the reason for the strong brightening of the activated prominence. The applicability of linear theory to the shock problem is tested with a nonlinear MHD simulation.

  7. Perceived prominence and scale types

    DEFF Research Database (Denmark)

    Tøndering, John; Jensen, Christian

    2005-01-01

    Three different scales which have been used to measure perceived prominence are evaluated in a perceptual experiment. Average scores of raters using a multi-level (31-point) scale, a simple binary (2-point) scale and an intermediate 4-point scale are almost identical. The potentially finer gradat...

  8. Stirring faces: mixing in a quiescent fluid

    CERN Document Server

    Brunton, Steven L

    2012-01-01

    This fluid dynamics video depicts the mixing that occurs as a two-dimensional flat plate plunges sinusoidally in a quiescent fluid. Finite-time Lyapunov exponents reveal sets that are attracting or repelling. As the flow field develops, strange faces emerge.

  9. Full Stokes Spectropolarimetry of Hα in Prominences

    Science.gov (United States)

    López Ariste, A.; Casini, R.; Paletou, F.; Tomczyk, S.; Lites, B. W.; Semel, M.; Landi Degl'Innocenti, E.; Trujillo Bueno, J.; Balasubramaniam, K. S.

    2005-03-01

    We report on spectropolarimetric observations of Hα in prominences made with the Télescope Héliographique pour l'Etude du Magnétisme et des Instabilités Solaires and the High Altitude Observatory/Advanced Stokes Polarimeter. Stokes Q and U show the expected profile shape from resonance scattering polarization and the Hanle effect. In contrast, most of the time, Stokes V does not show the antisymmetric profile shape typical of the Zeeman effect but a profile that indicates the presence of strong atomic orientation in the hydrogen levels, to an extent that cannot be explained by invoking the alignment-to-orientation transfer mechanism induced by the prominence magnetic field. We found that the largest signal amplitudes of Stokes V (comparable to that of Stokes Q and U) could be produced by a process of selective absorption of circularly polarized radiation from the photosphere, which requires that the prominence be in the vicinity of an active region. Although recent observations of active region filaments indicate such a selective absorption mechanism as a plausible explanation of the anomalous signals observed, the particular set of conditions that must be met suggest that a different explanation may be required to explain the almost ubiquitous symmetric V signal observed in Hα prominences. Therefore, we speculate that an alternative mechanism inducing strong atomic orientation at the observed level could be due to the presence of electric fields inducing an electric Hanle effect on Hα. Although we are still working toward a careful modeling of this effect, including both electric and magnetic fields, we present some preliminary considerations that seem to support this possibility.

  10. NUMERICAL SIMULATIONS OF THE MAGNETIC RAYLEIGH-TAYLOR INSTABILITY IN THE KIPPENHAHN-SCHLUeTER PROMINENCE MODEL. I. FORMATION OF UPFLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Hillier, Andrew; Isobe, Hiroaki; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan); Berger, Thomas, E-mail: andrew@kwasan.kyoto-u.ac.jp [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA (United States)

    2012-02-20

    The launch of the Hinode satellite led to the discovery of rising plumes, dark in chromospheric lines, that propagate from large ({approx}10 Mm) bubbles that form at the base of quiescent prominences. The plumes move through a height of approximately 10 Mm while developing highly turbulent profiles. The magnetic Rayleigh-Taylor instability was hypothesized to be the mechanism that drives these flows. In this study, using three-dimensional (3D) MHD simulations, we investigate the nonlinear stability of the Kippenhahn-Schlueter prominence model for the interchange mode of the magnetic Rayleigh-Taylor instability. The model simulates the rise of a buoyant tube inside the quiescent prominence model, where the interchange of magnetic field lines becomes possible at the boundary between the buoyant tube and the prominence. Hillier et al. presented the initial results of this study, where upflows of constant velocity (maximum found 6 km s{sup -1}) and a maximum plume width Almost-Equal-To 1.5 Mm which propagate through a height of approximately 6 Mm were found. Nonlinear interaction between plumes was found to be important for determining the plume dynamics. In this paper, using the results of ideal MHD simulations, we determine how the initial parameters for the model and buoyant tube affect the evolution of instability. We find that the 3D mode of the magnetic Rayleigh-Taylor instability grows, creating upflows aligned with the magnetic field of constant velocity (maximum found 7.3 km s{sup -1}). The width of the upflows is dependent on the initial conditions, with a range of 0.5-4 Mm which propagate through heights of 3-6 Mm. These results are in general agreement with the observations of the rising plumes.

  11. L183, a Quiescent Core?

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Some observed results of NH3 (1, 1) and (2, 2) line emission in the starless dark cloud L183 are reported. Our observation suggests that the dense core of L183 has a size of ~ 0.16pc ×0.1pc with a mass of ~ 12M⊙. A velocity gradient of 4km s-1pc-1 from the north to the south was detected. The velocity shift corresponds to a central mass of ~ 5M⊙. If it is caused by rotation, the mass would be much less than the value above. This suggests that there may be more mass in the envelope of L183 than in the central region. The analysis of our data and the evidence in the literature about L183 indicate that it may be undergoing a process of collapsing to form a low-mass binary dense core.

  12. Magnetic field in atypical prominence structures: Bubble, tornado and eruption

    CERN Document Server

    Levens, P J; Ariste, A López; Labrosse, N; Dalmasse, K; Gelly, B

    2016-01-01

    Spectropolarimetric observations of prominences have been obtained with the THEMIS telescope during four years of coordinated campaigns. Our aim is now to understand the conditions of the cool plasma and magnetism in `atypical' prominences, namely when the measured inclination of the magnetic field departs, to some extent, from the predominantly horizontal field found in `typical' prominences. What is the role of the magnetic field in these prominence types? Are plasma dynamics more important in these cases than the magnetic support? We focus our study on three types of `atypical' prominences (tornadoes, bubbles and jet-like prominence eruptions) that have all been observed by THEMIS in the He I D_3 line, from which the Stokes parameters can be derived. The magnetic field strength, inclination and azimuth in each pixel are obtained by using the Principal Component Analysis inversion method on a model of single scattering in the presence of the Hanle effect. The magnetic field in tornadoes is found to be more ...

  13. Inference of magnetic fields in inhomogeneous prominences

    Science.gov (United States)

    Milić, I.; Faurobert, M.; Atanacković, O.

    2017-01-01

    Context. Most of the quantitative information about the magnetic field vector in solar prominences comes from the analysis of the Hanle effect acting on lines formed by scattering. As these lines can be of non-negligible optical thickness, it is of interest to study the line formation process further. Aims: We investigate the multidimensional effects on the interpretation of spectropolarimetric observations, particularly on the inference of the magnetic field vector. We do this by analyzing the differences between multidimensional models, which involve fully self-consistent radiative transfer computations in the presence of spatial inhomogeneities and velocity fields, and those which rely on simple one-dimensional geometry. Methods: We study the formation of a prototype line in ad hoc inhomogeneous, isothermal 2D prominence models. We solve the NLTE polarized line formation problem in the presence of a large-scale oriented magnetic field. The resulting polarized line profiles are then interpreted (i.e. inverted) assuming a simple 1D slab model. Results: We find that differences between input and the inferred magnetic field vector are non-negligible. Namely, we almost universally find that the inferred field is weaker and more horizontal than the input field. Conclusions: Spatial inhomogeneities and radiative transfer have a strong effect on scattering line polarization in the optically thick lines. In real-life situations, ignoring these effects could lead to a serious misinterpretation of spectropolarimetric observations of chromospheric objects such as prominences.

  14. Inference of magnetic fields in inhomogeneous prominences

    CERN Document Server

    Milic, Ivan; Atanackovic, Olga

    2016-01-01

    Most of the quantitative information about the magnetic field vector in solar prominences comes from the analysis of the Hanle effect acting on lines formed by scattering. As these lines can be of non-negligible optical thickness, it is of interest to study the line formation process further. We investigate the multidimensional effects on the interpretation of spectropolarimetric observations, particularly on the inference of the magnetic field vector. We do this by analyzing the differences between multidimensional models, which involve fully self-consistent radiative transfer computations in the presence of spatial inhomogeneities and velocity fields, and those which rely on simple one-dimensional geometry. We study the formation of a prototype line in ad hoc inhomogeneous, isothermal 2D prominence models. We solve the NLTE polarized line formation problem in the presence of a large-scale oriented magnetic field. The resulting polarized line profiles are then interpreted (i.e. inverted) assuming a simple 1D...

  15. Neurotropic melanoma with prominent melanization.

    Science.gov (United States)

    Barnhill, R L; Bolognia, J L

    1995-10-01

    Neurotropic melanoma has generally been described in the context of desmoplastic melanoma. The vast majority of melanomas displaying neurotropism contain relatively little or no melanin. Herein, we report an unusual case of neurotropic melanoma with prominent melanin content. The patient developed a tumor notable for pagetoid (superficial spreading) melanoma with partial regression and a deep component characterized by perineurial aggregates of melanophages and intraneural infiltration by melanoma cells. This case serves to alert dermatopathologists to the fact that the spectrum of neurotropic melanoma includes tumors with perineurial aggregates of pigment-containing cells.

  16. Colors, Star formation Rates, and Environments of Star forming and Quiescent Galaxies at the Cosmic Noon

    CERN Document Server

    Feldmann, Robert; Hopkins, Philip F; Faucher-Giguère, Claude-André; Kereš, Dušan

    2016-01-01

    We analyze the SFRs, stellar masses, galaxy colors, and dust extinctions of galaxies in massive (10^12.5-10^13.5 M_sun) halos at z~2 in high-resolution, cosmological zoom-in simulations as part of the Feedback in Realistic Environments (FIRE) project. The simulations do not model feedback from AGN but reproduce well the observed relations between stellar and halo mass and between stellar mass and SFR. About half of the simulated massive galaxies at z~2 have broad-band colors classifying them as `quiescent', and the fraction of quiescent centrals is steeply decreasing towards higher redshift, in agreement with observations. However, our simulations do not reproduce the reddest of the quiescent galaxies observed at z~2. While simulated quiescent galaxies are less dusty than star forming galaxies, their broad band colors are often affected by moderate levels of interstellar dust. The star formation histories of the progenitors of z~2 star forming and quiescent galaxies are typically bursty, especially at early t...

  17. Neutral Atom Diffusion in a Partially Ionized Prominence Plasma

    Science.gov (United States)

    Gilbert, Holly

    2010-01-01

    The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized. it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material,

  18. Neutral Atom Diffusion in a Partially Ionized Prominence Plasma

    Science.gov (United States)

    Gilbert, Holly

    2010-01-01

    The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized. it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material,

  19. Evolution and Dynamics of a Solar Active Prominence

    CERN Document Server

    Magara, Tetsuya

    2015-01-01

    The life of a solar active prominence, one of the most remarkable objects on the Sun, is full of dynamics; after first appearing on the Sun the prominence continuously evolves with various internal motions and eventually produces a global eruption toward the interplane- tary space. Here we report that the whole life of an active prominence is successfully re- produced by performing as long-term a magnetohydrodynamic simulation of a magnetized prominence plasma as was ever done. The simulation reveals underlying dynamic processes that give rise to observed properties of an active prominence: invisible subsurface flows self- consistently produce the cancellation of magnetic flux observed at the photosphere, while observed and somewhat counterintuitive strong upflows are driven against gravity by en- hanced gas pressure gradient force along a magnetic field line locally standing vertical. The most highlighted dynamic event, transition into an eruptive phase, occurs as a natural con- sequence of the self-consiste...

  20. Investigating Variability of Quiescent Neutron Stars in the Globular Clusters NGC 6440 and Terzan 5

    CERN Document Server

    Walsh, A R; Bernardini, F

    2014-01-01

    The quiescent spectrum of neutron star low-mass X-ray binaries typically consists of two components - a thermal component associated with emission from the neutron star surface, and a non-thermal power-law component whose origin is not well understood. Spectral fitting of neutron star atmosphere models to the thermal component is one of the leading methods for measuring the neutron star radius. However, it has been known for years that the X-ray spectra of quiescent neutron stars vary between observations. While most quiescent variability is explained through a variable power-law component, the brightest and best-studied object, Cen X-4, requires a change in the thermal component and such thermal variability could be a problem for measuring neutron star radii. In this paper, we significantly increase the number of sources whose quiescent spectra have been studied for variability. We examine 9 potential quiescent neutron stars with luminosities <1E34 erg/s over the course of multiple Chandra observations of...

  1. Prominence Mass Supply and the Cavity

    CERN Document Server

    Schmit, Donald; Luna, Manuel; Karpen, Judy; Innes, Davina

    2013-01-01

    A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet emission (EUV) surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the SDO/AIA 171\\AA\\ bandpass near the prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset ...

  2. NUMERICAL SIMULATIONS OF THE MAGNETIC RAYLEIGH-TAYLOR INSTABILITY IN THE KIPPENHAHN-SCHLUeTER PROMINENCE MODEL. II. RECONNECTION-TRIGGERED DOWNFLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Hillier, Andrew; Isobe, Hiroaki; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan); Berger, Thomas [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA (United States)

    2012-09-10

    The launch of the Hinode satellite has allowed high-resolution observations of supersonic bright downflows in quiescent prominences, known as prominence knots. We present observations in the Ca II H spectral line using the Solar Optical Telescope on board the Hinode satellite of a descending plasma knot of size {approx}900 km. The knot initially undergoes ballistic motion before undergoing impulsive accelerations at the same time as experiencing increases in intensity. We also present a subset of our three-dimensional magnetohydrodynamic simulations, performed to investigate the nonlinear stability of the Kippenhahn-Shlueter prominence model to the magnetic Rayleigh-Taylor instability in which interchange reconnection occurs. The interchange reconnection in the model breaks the force balance along the field lines which initiates the downflows. The downflows propagate with a downward fluid velocity of {approx}15 km s{sup -1} and a characteristic size of {approx}700 km. We conclude that the observed plasma blob and the simulated downflow are driven by the breaking of the force balance along the magnetic field as a result of a change in magnetic topology caused by reconnection of the magnetic field.

  3. Quiescent and Active Tear Protein Profiles to Predict Vernal Keratoconjunctivitis Reactivation

    Directory of Open Access Journals (Sweden)

    Alessandra Micera

    2016-01-01

    Full Text Available Objective. Vernal keratoconjunctivitis (VKC is a chronic recurrent bilateral inflammation of the conjunctiva associated with atopy. Several inflammatory and tissue remodeling factors contribute to VKC disease. The aim is to provide a chip-based protein analysis in tears from patients suffering from quiescent or active VKC. Methods. This study cohort included 16 consecutive patients with VKC and 10 controls. Participants were subjected to clinical assessment of ocular surface and tear sampling. Total protein quantification, total protein sketch, and protein array (sixty protein candidates were evaluated. Results. An overall increased Fluorescent Intensity expression was observed in VKC arrays. Particularly, IL1β, IL15, IL21, Eotaxin2, TACE, MIP1α, MIP3α, NCAM1, ICAM2, βNGF, NT4, BDNF, βFGF, SCF, MMP1, and MMP2 were increased in quiescent VKC. Of those candidates, only IL1β, IL15, IL21, βNGF, SCF, MMP2, Eotaxin2, TACE, MIP1α, MIP3α, NCAM1, and ICAM2 were increased in both active and quiescent VKC. Finally, NT4, βFGF, and MMP1 were highly increased in active VKC. Conclusion. A distinct “protein tear-print” characterizes VKC activity, confirming some previously reported factors and highlighting some new candidates common to quiescent and active states. Those candidates expressed in quiescent VKC might be considered as predictive indicators of VKC reactivation and/or exacerbation out-of-season.

  4. Quiescent and Active Tear Protein Profiles to Predict Vernal Keratoconjunctivitis Reactivation

    Science.gov (United States)

    Micera, Alessandra; Di Zazzo, Antonio; Esposito, Graziana; Sgrulletta, Roberto; Calder, Virginia L.; Bonini, Stefano

    2016-01-01

    Objective. Vernal keratoconjunctivitis (VKC) is a chronic recurrent bilateral inflammation of the conjunctiva associated with atopy. Several inflammatory and tissue remodeling factors contribute to VKC disease. The aim is to provide a chip-based protein analysis in tears from patients suffering from quiescent or active VKC. Methods. This study cohort included 16 consecutive patients with VKC and 10 controls. Participants were subjected to clinical assessment of ocular surface and tear sampling. Total protein quantification, total protein sketch, and protein array (sixty protein candidates) were evaluated. Results. An overall increased Fluorescent Intensity expression was observed in VKC arrays. Particularly, IL1β, IL15, IL21, Eotaxin2, TACE, MIP1α, MIP3α, NCAM1, ICAM2, βNGF, NT4, BDNF, βFGF, SCF, MMP1, and MMP2 were increased in quiescent VKC. Of those candidates, only IL1β, IL15, IL21, βNGF, SCF, MMP2, Eotaxin2, TACE, MIP1α, MIP3α, NCAM1, and ICAM2 were increased in both active and quiescent VKC. Finally, NT4, βFGF, and MMP1 were highly increased in active VKC. Conclusion. A distinct “protein tear-print” characterizes VKC activity, confirming some previously reported factors and highlighting some new candidates common to quiescent and active states. Those candidates expressed in quiescent VKC might be considered as predictive indicators of VKC reactivation and/or exacerbation out-of-season. PMID:26989694

  5. Ices in the Quiescent IC 5146 Dense Cloud

    CERN Document Server

    Chiar, J E; Allamandola, L J; Boogert, A C A; Ennico, K; Greene, T P; Geballe, T R; Keane, J V; Lada, C J; Mason, R E; Roellig, T L; Sandford, S A; Tielens, A G G M; Werner, M W; Whittet, D C B; Decin, L; Eriksson, K

    2011-01-01

    This paper presents spectra in the 2 to 20 micron range of quiescent cloud material located in the IC 5146 cloud complex. The spectra were obtained with NASA's Infrared Telescope Facility (IRTF) SpeX instrument and the Spitzer Space Telescope's Infrared Spectrometer. We use these spectra to investigate dust and ice absorption features in pristine regions of the cloud that are unaltered by embedded stars. We find that the H2O-ice threshold extinction is 4.03+/-0.05 mag. Once foreground extinction is taken into account, however, the threshold drops to 3.2 mag, equivalent to that found for the Taurus dark cloud, generally assumed to be the touchstone quiescent cloud against which all other dense cloud and embedded young stellar object observations are compared. Substructure in the trough of the silicate band for two sources is attributed to CH3OH and NH3 in the ices, present at the ~2% and ~5% levels, respectively, relative to H2O-ice. The correlation of the silicate feature with the E(J-K) color excess is found...

  6. The Fraction of Quiescent Massive Galaxies in the Early Universe

    CERN Document Server

    Fontana, A; Grazian, A; Pentericci, L; Fiore, F; Castellano, M; Giallongo, E; Menci, N; Salimbeni, S; Cristiani, S; Nonino, M; Vanzella, E

    2009-01-01

    Aims: The aim of this work is to collect a complete, mass--selected sample of galaxies with very low specific star formation rate, for a comparison with the prediction of recent theoretical models. Method: We use the 24/K flux ratio, complemented by the SED fitting to the full 0.35-8.0 mum spectral distribution, to select quiescent galaxies from z~0.4 to z~4 in the GOODS--MUSIC sample. Our observational selection can be translated into thresholds on the specific star formation rate SFR/M_*, that can be used to compare with the theoretical predictions. Results: We find that, in the framework of the well known global decline of the quiescent fraction with redshift, a non-negligible fraction ~15-20% of massive galaxies with very low specific star formation rate exists up to z~4, including a tail of "Red&Dead" galaxies with SFR/M_*<10^{-11}/yr. Recent theoretical models vary to a large extent in the prediction of the fraction of galaxies with very low specific star formation rates, and are unable to provid...

  7. Differentiating quiescent cancer cell populations in heterogeneous samples with fluorescence lifetime imaging

    Science.gov (United States)

    Heaster, Tiffany M.; Walsh, Alex J.; Skala, Melissa C.

    2016-03-01

    Measurement of relative fluorescence intensities of NAD(P)H and FAD with fluorescence lifetime imaging (FLIM) allows metabolic characterization of cancerous populations and correlation to treatment response. However, quiescent populations of cancer cells introduce heterogeneity to the tumor and exhibit resistance to standard therapies, requiring a better understanding of this influence on treatment outcome. Significant differences were observed between proliferating and quiescent cell populations upon comparison of respective redox ratios (pFAD lifetimes (p<0.05) across monolayers and in mixed samples. These results demonstrate that metabolic activity may function as a marker for separation and characterization of proliferating and quiescent cancer cells within mixed samples, contributing to comprehensive investigation of heterogeneity-dependent drug resistance.

  8. Contrasting quiescent G0 phase with mitotic cell cycling in the mouse immune system.

    Directory of Open Access Journals (Sweden)

    Michio Tomura

    Full Text Available A transgenic mouse line expressing Fucci (fluorescent ubiquitination-based cell-cycle indicator probes allows us to monitor the cell cycle in the hematopoietic system. Two populations with high and low intensities of Fucci signals for Cdt1(30/120 accumulation were identified by FACS analysis, and these correspond to quiescent G0 and cycling G1 cells, respectively. We observed the transition of immune cells between quiescent and proliferative phases in lymphoid organs during differentiation and immune responses.

  9. Evidence for widespread active galactic nucleus activity among massive quiescent galaxies at z ~ 2

    DEFF Research Database (Denmark)

    Olsen, K.P.; Rasmussen, J.; Toft, S.;

    2013-01-01

    We quantify the presence of active galactic nuclei (AGNs) in a mass-complete (M > 5 × 10 M ) sample of 123 star-forming and quiescent galaxies at 1.5 = z = 2.5, using X-ray data from the 4 Ms Chandra Deep Field-South (CDF-S) survey. 41% ± 7% of the galaxies are detected directly in X-rays, 22% ± ......%-65%). Our discovery of the ubiquity of AGNs in massive, quiescent z ~ 2 galaxies provides observational support for the importance of AGNs in impeding star formation during galaxy evolution. © 2013. The American Astronomical Society. All rights reserved.....

  10. Targeting Quiescent Cancer Cells to Eliminate Tumor Recurrence After Therapy

    Science.gov (United States)

    2015-10-01

    AD_________________ (Leave blank) Award Number: W81XWH-14-1-0350 TITLE: Targeting Quiescent Cancer Cells to Eliminate Tumor Recurrence After...30 Sep 2014 - 29 Sep 2015 4. TITLE AND SUBTILE Targeting Quiescent Cancer Cells to Eliminate Tumor Recurrence After Therapy 5a. CONTRACT NUMBER...Innovative reporter gene systems are designed to mark quiescent or proliferating lung cancer cells (Aim 1) and then used to track and trace the dynamics of

  11. On the magnetism and dynamics of prominence legs hosting tornadoes

    CERN Document Server

    Gonzalez, M J Martinez; Arregui, I; Collados, M; Beck, C; Rodriguez, J de la Cruz

    2016-01-01

    Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires understanding their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here, we analyze four consecutive spectropolarimetric scans of a prominence hosting tornadoes on its legs which help us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation probably related to the motion of the fibrils. Concerning the dynamics, we argue that 1) if rotation exists, it is intermittent, lasting no ...

  12. 3D WHOLE-PROMINENCE FINE STRUCTURE MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Gunár, Stanislav; Mackay, Duncan H. [School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews, KY16 9SS (United Kingdom)

    2015-04-20

    We present the first 3D whole-prominence fine structure model. The model combines a 3D magnetic field configuration of an entire prominence obtained from nonlinear force-free field simulations, with a detailed description of the prominence plasma. The plasma is located in magnetic dips in hydrostatic equilibrium and is distributed along multiple fine structures within the 3D magnetic model. Through the use of a novel radiative transfer visualization technique for the Hα line such plasma-loaded magnetic field model produces synthetic images of the modeled prominence comparable with high-resolution observations. This allows us for the first time to use a single technique to consistently study, in both emission on the limb and absorption against the solar disk, the fine structures of prominences/filaments produced by a magnetic field model.

  13. Explosive Instability of Prominence Flux Ropes

    Energy Technology Data Exchange (ETDEWEB)

    Hurricane, O; Fong, R H L; Cowley, S C

    2002-09-04

    The rapid, Alfvenic, time scale of erupting solar-prominences has been an enigma ever since they where first identified. Investigators have proposed a variety of different mechanisms in an effort to account for the abrupt reconfiguration observed. No one mechanism clearly stands out as the single cause of these explosive events. Recent analysis has demonstrated that field lines in the solar atmosphere are metastable to ballooning type instabilities. It has been found previously that in ideal MHD plasmas marginally unstable ballooning modes inevitably become ''explosive'' evolving towards a finite time singularity via a nonlinear 3D instability called ''Nonlinear Magnetohydrodynamic Detonation.'' Thus, this mechanism is a good candidate to explain explosive events observed in the solar atmosphere of our star or in others.

  14. Hinode, SDO AIA, and CoMP Observations of a Coronal Cavity with a Hot Core

    Science.gov (United States)

    Reeves, K.; Jibben, P.

    2014-12-01

    Coronal cavities are low emission regions often situated around quiescent prominences. Prominences may exist for days or months prior to eruption and the magnetic structure of the cavity during the quiescent period is important to understanding the pre-eruption phase. We describe observations of a coronal cavity with a hot core situated above a polar crown prominence. The cavity, visible on the southwest limb, was observed for a period of three hours as a Hinode Coordinated Observation (HOP 114). Using Hinode's X-ray Telescope (XRT) and EUV Imaging Spectrometer (EIS) we present the thermal emission properties and coronal velocity structures of the cavity. We find the core has hotter temperatures than the surrounding plasma and there is evidence of turbulent velocities within the cavity. We also investigate the interaction of the cavity with the prominence material using Solar Dynamic Observatory (SDO) Atmospheric Imaging Assembly (AIA) data and H-alpha data from Hinode's Solar Optical Telescope (SOT). We find evidence of hot plasma at the spine of the prominence reaching into the cavity. These observations suggest a cylindrical flux tube best represents the cavity structure. The magnetic structure of the cavity is further discussed using data from the Coronal Multichannel Polarimeter (CoMP). This work is supported by under contract SP02H1701R from Lockheed-Martin to SAO, contract NNM07AB07C from NASA to SAO and grant number NNX12AI30G from NASA to SAO.

  15. Modeling Chemical Reactors I: Quiescent Reactors

    CERN Document Server

    Michoski, C E; Schmitz, P G

    2010-01-01

    We introduce a fully generalized quiescent chemical reactor system in arbitrary space $\\vdim =1,2$ or 3, with $n\\in\\mathbb{N}$ chemical constituents $\\alpha_{i}$, where the character of the numerical solution is strongly determined by the relative scaling between the local reactivity of species $\\alpha_{i}$ and the local functional diffusivity $\\mathscr{D}_{ij}(\\alpha)$ of the reaction mixture. We develop an operator time-splitting predictor multi-corrector RK--LDG scheme, and utilize $hp$-adaptivity relying only on the entropy $\\mathscr{S}_{\\mathfrak{R}}$ of the reactive system $\\mathfrak{R}$. This condition preserves these bounded nonlinear entropy functionals as a necessarily enforced stability condition on the coupled system. We apply this scheme to a number of application problems in chemical kinetics; including a difficult classical problem arising in nonequilibrium thermodynamics known as the Belousov-Zhabotinskii reaction where we utilize a concentration-dependent diffusivity tensor $\\mathscr{D}_{ij}(...

  16. Detection of Prominent Stellar Disks in the Progenitors of Present-day Massive Elliptical Galaxies

    Science.gov (United States)

    Davari, Roozbeh H.; Ho, Luis C.; Mobasher, Bahram; Canalizo, Gabriela

    2017-02-01

    Massive galaxies at high redshifts (z > 2) show different characteristics from their local counterparts: they are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single Sérsic profiles and performing bulge+disk decompositions. We analyze ∼250 massive galaxies selected from all CANDELS fields (COSMOS, UDS, EGS, GOODS-South, and GOODS-North). We confirm that both star-forming and quiescent galaxies increase their sizes significantly from z ≈ 2.5 to the present day. The global Sérsic index of quiescent galaxies increases over time (from n ≈ 2.5 to n > 4), while that of star-forming galaxies remains roughly constant (n ≈ 2.5). By decomposing galaxy profiles into bulge+disk components, we find that massive galaxies at high redshift have prominent stellar disks, which are also evident from visual inspection of the images. By z ≈ 0.5, the majority of the disks disappear and massive quiescent galaxies begin to resemble the local elliptical galaxies. Star-forming galaxies have lower bulge-to-total ratios (B/T) than their quiescent counterparts in each redshift bin. The bulges of star-forming and quiescent galaxies follow different evolutionary histories, while their disks evolve similarly. Based on our morphological analysis and previous cosmological simulations, we argue that major mergers, along with minor mergers, have played a crucial role in the significant increase in size of high-z galaxies and the destruction of their massive and large-scale disks.

  17. The hard quiescent spectrum of the neutron-star X-ray transient EXO 1745-248 in the globular cluster Terzan 5

    CERN Document Server

    Wijnands, R; Pooley, D; Edmonds, P D; Lewin, W H G; Grindlay, J E; Jonker, P G; Miller, J M; Wijnands, Rudy; Heinke, Craig O.; Pooley, David; Edmonds, Peter D.; Lewin, Walter H. G.; Grindlay, Jonathan E.; Jonker, Peter G.; Miller, Jon M.

    2003-01-01

    We present a Chandra observation of the globular cluster Terzan 5 during times when the neutron-star X-ray transient EXO 1745-248 located in this cluster was in its quiescent state. We detected the quiescent system with a (0.5-10 keV) luminosity of ~2 x 10^{33} ergs/s. This is similar to several other neutron-star transients observed in their quiescent states. However, the quiescent X-ray spectrum of EXO 1745--48 was dominated by a hard power-law component instead of the soft component that usually dominates the quiescent emission of other neutron-star X-ray transients. This soft component could not conclusively be detected in EXO 1745-248 and we conclude that it contributed at most 10% of the quiescent flux in the energy range 0.5-10 keV. EXO 1745-248 is only the second neutron-star transient whose quiescent spectrum is dominated by the hard component (SAX J1808.4-3658 is the other one). We discuss possible explanations for this unusual behavior of EXO 1745-248, its relationship to other quiescent neutron-st...

  18. The Quiescent Neutron Star and Hierarchical Triple, 4U2129+47

    Science.gov (United States)

    Nowak, Michael; Chakrabarty, Deepto; Wilms, Joern; Kühnel, Matthias

    2016-04-01

    4U 2129+47 is a quiescent, eclipsing neutron star that 35 years ago showed typical "Accretion Disk Corona" (ADC) behavior akin to the prototype of the class, X1822-371. Now faded, 4U 2129+47 provides tests of neutron star quiescent emission. It has shown low temperature thermal emission (the neutron star surface), a power law tail (of unknown origin, although possibly due to a pulsar wind interacting with an incoming accretion stream; Campana et al. 1998), and sinusoidally modulated absorption (the disk) as well as periodic X-ray eclipses. Subsequent XMM-Newton and Chandra observations, taken 2007 through Fall 2015, indicate that the hard tail and sinusoidal modulation disappeared, as if the accretion stream and disk have vanished. With the intiial loss of the hard tail, the soft X-ray flux also dropped, but since has remained steady, showing no signs of further neutron star cooling in the subsequent 8 years. We compare this behavior to recent NuSTAR observations of the quiescent neutron star Cen X-4, where the hard tail seems to persist over a wider range of quiescent flux, and correlate with the soft X-ray. It also has been speculated that 4U 2129+47 is part of a hierarchical triple system, with the third body in a much longer orbit. We use the Chandra and XMM-Newton eclipse ephemeris residuals to describe this third body orbit.

  19. Detection limits of about 350 prominent lines of 65 elements observed in 50 and 27 MHz inductively coupled plasmas (ICP): effects of source characteristics, noise and spectral bandwidth-"Standard" values for the 50 MHz ICP

    Science.gov (United States)

    Boumans, P. W. J. M.; Vrakking, J. J. A. M.

    This paper links up with a previous publication by the same authors [ Spectrochim. Acta41B, 1235 (1986)] dealing with the measurement of the effective line profiles of about 350 prominent lines at high spectral resolution and the determination of the physical widths of these lines. In the present work the line widths are used for a breakdown of the detection limits obtained with these lines using different ICPs and different spectrometers. This breakdown takes into account the separate effects of source characteristics, noise, and spectral bandwidth. The availability of the numerical values of the physical widths of a large number of lines permitted a more rigorous approach than in a previous work [ Spectrochim. Acta40B, 1437 (1985)]. The present approach was applied to detection limits obtained in this work with a 50 MHz ICP at high spectral resolution and to results reported by W INGEet al. [ Appl. Spectrosc.33, 206 (1979)] and WOHLERS [ ICP Information Newslett.10, 601 (1985)]for 27 MHz ICPs. The 50 MHz ICP was shown to have an advantage in source signal-to-background ratio (SBR) with respect to either of the two 27 MHz ICPs. This SBR advantage was a factor of 3-15 with respect to the "Winge ICP" and a factor of 2-6 with respect to the "Wohlers ICP". The approach was also used to convert detection limits measured in the 50 MHz ICP at high resolution into values for 15 pm spectral bandwidth and a relative standard deviation of the background signal equal to 1%. These values are recommended as standards of performance for the conventional argon ICP. The paper comprises a tabulation of the complete results for the 350 prominent lines and includes four sets of detection limits for these lines.

  20. Loudness predicts prominence: Fundamental frequency lends little

    Science.gov (United States)

    Kochanski, G.; Grabe, E.; Coleman, J.; Rosner, B.

    2005-08-01

    We explored a database covering seven dialects of British and Irish English and three different styles of speech to find acoustic correlates of prominence. We built classifiers, trained the classifiers on human prominence/nonprominence judgments, and then evaluated how well they behaved. The classifiers operate on 452 ms windows centered on syllables, using different acoustic measures. By comparing the performance of classifiers based on different measures, we can learn how prominence is expressed in speech. Contrary to textbooks and common assumption, fundamental frequency (f0) played a minor role in distinguishing prominent syllables from the rest of the utterance. Instead, speakers primarily marked prominence with patterns of loudness and duration. Two other acoustic measures that we examined also played a minor role, comparable to f0. All dialects and speaking styles studied here share a common definition of prominence. The result is robust to differences in labeling practice and the dialect of the labeler.

  1. On the Evolution of the Central Density of Quiescent Galaxies

    Science.gov (United States)

    Tacchella, Sandro; Carollo, C. Marcella; Faber, S. M.; Cibinel, Anna; Dekel, Avishai; Koo, David C.; Renzini, Alvio; Woo, Joanna

    2017-07-01

    We investigate the origin of the evolution of the population-averaged central stellar mass density (Σ1) of quiescent galaxies (QGs) by probing the relation between stellar age and Σ1 at z ˜ 0. We use the Zurich ENvironmental Study (ZENS), which is a survey of galaxy groups with a large fraction of satellite galaxies. QGs shape a narrow locus in the Σ1-M ⋆ plane, which we refer to as Σ1 ridgeline. Colors of (B - I) and (I - J) are used to divide QGs into three age categories: young (4 Gyr). At fixed stellar mass, old QGs on the Σ1 ridgeline have higher Σ1 than young QGs. This shows that galaxies landing on the Σ1 ridgeline at later epochs arrive with lower Σ1, which drives the zeropoint of the ridgeline down with time. We compare the present-day zeropoint of the oldest population at z = 0 with the zeropoint of the quiescent population 4 Gyr back in time, at z = 0.37. These zeropoints are identical, showing that the intrinsic evolution of individual galaxies after they arrive on the Σ1 ridgeline must be negligible, or must evolve parallel to the ridgeline during this interval. The observed evolution of the global zeropoint of 0.07 dex over the last 4 Gyr is thus largely due to the continuous addition of newly quenched galaxies with lower Σ1 at later times (“progenitor bias”). While these results refer to the satellite-rich ZENS sample as a whole, our work suggests a similar age-Σ1 trend for central galaxies.

  2. Obscuration of Flare Emission by an Eruptive Prominence

    CERN Document Server

    Gopalswamy, Nat

    2013-01-01

    We report on the eclipsing of microwave flare emission by an eruptive prominence from a neighboring region as observed by the Nobeyama Radioheliograph at 17 GHz. The obscuration of the flare emission appears as a dimming feature in the microwave flare light curve. We use the dimming feature to derive the temperature of the prominence and the distribution of heating along the length of the filament. We find that the prominence is heated to a temperature above the quiet Sun temperature at 17 GHz. The duration of the dimming is the time taken by the eruptive prominence in passing over the flaring region. We also find evidence for the obscuration in EUV images obtained by the Solar and Heliospheric Observatory (SOHO) mission.

  3. Suppressing star formation in quiescent galaxies with supermassive black hole winds.

    Science.gov (United States)

    Cheung, Edmond; Bundy, Kevin; Cappellari, Michele; Peirani, Sébastien; Rujopakarn, Wiphu; Westfall, Kyle; Yan, Renbin; Bershady, Matthew; Greene, Jenny E; Heckman, Timothy M; Drory, Niv; Law, David R; Masters, Karen L; Thomas, Daniel; Wake, David A; Weijmans, Anne-Marie; Rubin, Kate; Belfiore, Francesco; Vulcani, Benedetta; Chen, Yan-mei; Zhang, Kai; Gelfand, Joseph D; Bizyaev, Dmitry; Roman-Lopes, A; Schneider, Donald P

    2016-05-26

    Quiescent galaxies with little or no ongoing star formation dominate the population of galaxies with masses above 2 × 10(10) times that of the Sun; the number of quiescent galaxies has increased by a factor of about 25 over the past ten billion years (refs 1-4). Once star formation has been shut down, perhaps during the quasar phase of rapid accretion onto a supermassive black hole, an unknown mechanism must remove or heat the gas that is subsequently accreted from either stellar mass loss or mergers and that would otherwise cool to form stars. Energy output from a black hole accreting at a low rate has been proposed, but observational evidence for this in the form of expanding hot gas shells is indirect and limited to radio galaxies at the centres of clusters, which are too rare to explain the vast majority of the quiescent population. Here we report bisymmetric emission features co-aligned with strong ionized-gas velocity gradients from which we infer the presence of centrally driven winds in typical quiescent galaxies that host low-luminosity active nuclei. These galaxies are surprisingly common, accounting for as much as ten per cent of the quiescent population with masses around 2 × 10(10) times that of the Sun. In a prototypical example, we calculate that the energy input from the galaxy's low-level active supermassive black hole is capable of driving the observed wind, which contains sufficient mechanical energy to heat ambient, cooler gas (also detected) and thereby suppress star formation.

  4. Ultrastructure of quiescent oocytes of Cebus albifrons.

    Science.gov (United States)

    Barton, B R; Hertig, A T

    1975-11-01

    Quiescent oocytes of the monkey Cebus albifrons were examined with the electron microscope. In many respects the ultrastructure of these cells was similar to that of other mammalian species. Elongate and oval mitochondria, lamellar Golgi complexes, small profiles of smooth endoplasmic reticulum, and vacuolar organelles were randomly distributed around a round nucleus which usually contained a nucleolus and clumps of heterochromatin. Among the unusual morphological characteristics of these oocytes are 'membranous aggregates', membrane-bound organelles containing a complex of convoluted membranes, some very dense rod-like structures and a droplet of moderate density which resembles lipid. A similar droplet is frequently found in mitochondria. Rough endoplasmic reticulum is abundant in many of these oocytes, forming parallel arrays and concentric rings around the nucleus. Folded membrane complexes, apparent elaborations of smooth endoplasmic reticulum, are frequently found in the cytoplasm in continuity with cisternae of smooth and rough endoplasmic reticulum and associated with vesicles which often contain flocculent material. The morphology of Cebus oocytes suggests a greater rate of steroid and protein synthesis, transport, and storage than is usually indicated by the ultrastructure of other mammalian oocytes.

  5. EVIDENCE FOR WIDESPREAD ACTIVE GALACTIC NUCLEUS ACTIVITY AMONG MASSIVE QUIESCENT GALAXIES AT z {approx} 2

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Karen P.; Rasmussen, Jesper; Toft, Sune; Zirm, Andrew W., E-mail: karen@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2013-02-10

    We quantify the presence of active galactic nuclei (AGNs) in a mass-complete (M {sub *} > 5 Multiplication-Sign 10{sup 10} M {sub Sun }) sample of 123 star-forming and quiescent galaxies at 1.5 {<=} z {<=} 2.5, using X-ray data from the 4 Ms Chandra Deep Field-South (CDF-S) survey. 41% {+-} 7% of the galaxies are detected directly in X-rays, 22% {+-} 5% with rest-frame 0.5-8 keV luminosities consistent with hosting luminous AGNs (L {sub 0.5-8keV} > 3 Multiplication-Sign 10{sup 42} erg s{sup -1}). The latter fraction is similar for star-forming and quiescent galaxies, and does not depend on galaxy stellar mass, suggesting that perhaps luminous AGNs are triggered by external effects such as mergers. We detect significant mean X-ray signals in stacked images for both the individually non-detected star-forming and quiescent galaxies, with spectra consistent with star formation only and/or a low-luminosity AGN in both cases. Comparing star formation rates inferred from the 2-10 keV luminosities to those from rest-frame IR+UV emission, we find evidence for an X-ray excess indicative of low-luminosity AGNs. Among the quiescent galaxies, the excess suggests that as many as 70%-100% of these contain low- or high-luminosity AGNs, while the corresponding fraction is lower among star-forming galaxies (43%-65%). Our discovery of the ubiquity of AGNs in massive, quiescent z {approx} 2 galaxies provides observational support for the importance of AGNs in impeding star formation during galaxy evolution.

  6. Synthetic polarimetric spectra from stellar prominences

    Science.gov (United States)

    Felipe, T.; Martínez González, M. J.; Asensio Ramos, A.

    2017-02-01

    Stellar prominences detected in rapidly rotating stars serve as probes of the magnetism in the corona of cool stars. We have synthesized the temporal evolution of the Stokes profiles generated in the He I 10 830 and 5876 Å triplets during the rotation of a prominence around a star. The synthesis was performed with the HAZEL code using a cloud model in which the prominence is characterized by a slab located at a fixed latitude and height. It accounts for the scattering polarization and Zeeman and Hanle effects. Several cases with different prominence magnetic field strengths and orientations have been analysed. The results show an emission feature that drifts across the profile while the prominence is out of the stellar disc. When the prominence eclipses the star, the intensity profile shows an absorption. The scattering induced by the prominence generates linear polarization signals in Stokes Q and U profiles, which are modified by the Hanle effect when a magnetic field is present. Due to the Zeeman effect, Stokes V profiles show a signal with very low amplitude when the magnetic field along the line of sight is different from zero. The estimated linear polarization signals could potentially be detected with the future spectropolarimeter Mid-resolution InfRAreD Astronomical Spectrograph, to be attached to Gran Telescopio Canarias telescope.

  7. Synthetic polarimetric spectra from stellar prominences

    CERN Document Server

    Felipe, T; Ramos, A Asensio

    2016-01-01

    Stellar prominences detected in rapidly rotating stars serve as probes of the magnetism in the corona of cool stars. We have synthesized the temporal evolution of the Stokes profiles generated in the He I 10830 and 5876 A triplets during the rotation of a prominence around a star. The synthesis was performed with the HAZEL code using a cloud model in which the prominence is characterized by a slab located at a fixed latitude and height. It accounts for the scattering polarization and Zeeman and Hanle effects. Several cases with different prominence magnetic field strengths and orientations have been analyzed. The results show an emission feature that drifts across the profile while the prominence is out of the stellar disk. When the prominence eclipses the star, the intensity profile shows an absorption. The scattering induced by the prominence generates linear polarization signals in Stokes Q and U profiles, which are modified by the Hanle effect when a magnetic field is present. Due to the Zeeman effect, St...

  8. Solar Prominence Modelling and Plasma Diagnostics at ALMA Wavelengths

    Science.gov (United States)

    Rodger, Andrew; Labrosse, Nicolas

    2017-09-01

    Our aim is to test potential solar prominence plasma diagnostics as obtained with the new solar capability of the Atacama Large Millimeter/submillimeter Array (ALMA). We investigate the thermal and plasma diagnostic potential of ALMA for solar prominences through the computation of brightness temperatures at ALMA wavelengths. The brightness temperature, for a chosen line of sight, is calculated using the densities of electrons, hydrogen, and helium obtained from a radiative transfer code under non-local thermodynamic equilibrium (non-LTE) conditions, as well as the input internal parameters of the prominence model in consideration. Two distinct sets of prominence models were used: isothermal-isobaric fine-structure threads, and large-scale structures with radially increasing temperature distributions representing the prominence-to-corona transition region. We compute brightness temperatures over the range of wavelengths in which ALMA is capable of observing (0.32 - 9.6 mm), however, we particularly focus on the bands available to solar observers in ALMA cycles 4 and 5, namely 2.6 - 3.6 mm (Band 3) and 1.1 - 1.4 mm (Band 6). We show how the computed brightness temperatures and optical thicknesses in our models vary with the plasma parameters (temperature and pressure) and the wavelength of observation. We then study how ALMA observables such as the ratio of brightness temperatures at two frequencies can be used to estimate the optical thickness and the emission measure for isothermal and non-isothermal prominences. From this study we conclude that for both sets of models, ALMA presents a strong thermal diagnostic capability, provided that the interpretation of observations is supported by the use of non-LTE simulation results.

  9. Targeting Quiescent Cancer Cells to Eliminate Tumor Recurrence After Therapy

    Science.gov (United States)

    2016-12-01

    AD_________________ Award Number: W81XWH-14-1-0350 TITLE: Targeting Quiescent Cancer Cells to Eliminate Tumor Recurrence After Therapy PRINCIPAL...30 Sep 2014 - 29 Sep 2016 4. TITLE AND SUBTILE Targeting Quiescent Cancer Cells to Eliminate Tumor Recurrence After Therapy 5a. CONTRACT NUMBER... cancer . To eradicate chemoresistant tumor cells, it is important to identify the subset of tumor cells that can survive from chemotherapy and

  10. Interpretation of the prominence differential emissions measure for 3 geometries

    Science.gov (United States)

    Schmahl, E. J.; Orrall, F. Q.

    1986-01-01

    Researchers have used prominence extreme ultraviolet line intensities observed from Skylab to derive the differential emission measure Q(T) in the prominence-corona (PC) interface from 3 x 10,000 to 3 times 1 million K, including the effects of Lyman Continuum absorption. Using lines both shortward and longward of the Lyman limit, researchers have estimated the importance of absorption as function of temperature. The magnitude of the absorption, as well as its rate of increase as a function of temperature, place limits on the thread scales and the character of the interfilar medium. Researchers have calculated models based on three assumed geometries: (1) threads with hot sheaths and cool cores; (2) isothermal threads; and (3) threads with longitudinal temperature gradients along the magnetic field. Comparison of the absorption computed from these models with the observed absorption in prominences shows that none of the geometries is totally satisfactory.

  11. Topic prominence in Chinese EFL learners’ interlanguage

    Directory of Open Access Journals (Sweden)

    Shaopeng Li

    2014-01-01

    Full Text Available The present study aims to investigate the general characteristics of topicprominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from a discourse perspective. Topic structures mainly appear in Chinese discourse in the form of topic chains (Wang, 2002; 2004. The research target are the topic chain, which is the main topic-prominent structure in Chinese discourse, and zero anaphora, which is the most common topic anaphora in the topic chain. Two important findings emerged from the present study. First, the characteristics of Chinese topic chains are transferrable to the interlanguage of Chinese EFL learners, thus resulting in overgeneralization of the zero anaphora. Second, the interlanguage discourse of Chinese EFL learners reflects a change of the second language acquisition process from topic-prominence to subject-prominence, thus lending support to the discourse transfer hypothesis.

  12. The Hβ Chromospheric Magnetic Field in a Quiescent Filament

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    We observed the line-of-sight magnetic field in the chromosphereandphotosphere of a large quiescent filament on the solar disk on September 6, 2001using the Solar Magnetic Field Telescope in Huairou Solar Observing Station. Thechromospheric and photospheric magnetograms together with Hβ filtergrams of thefilament were examined. The filament was located on the neutral line of the largescale longitudinal magnetic field in the photosphere and the chromosphere. Thelateral feet of the filament .were found to be related to magnetic structures with op-posite polarities. Two small lateral feet are linked to weak parasitic polarity. Thereis a negative magnetic structure in the photosphere under a break of the filament.At the location corresponding to the filament in the chromospheric magnetograms,the magnetic strength is found to be about 40-70 Gauss (measuring error about 39Gauss). The magnetic signal indicates the amplitude and orientation of the internalmagnetic field in the filament. We discuss several possible causes which may pro-duce such a measured signal. A twisted magnetic configuration inside the filamentis suggested .

  13. Direct cell-cell contact with the vascular niche maintains quiescent neural stem cells

    Science.gov (United States)

    Ottone, Cristina; Krusche, Benjamin; Whitby, Ariadne; Clements, Melanie; Quadrato, Giorgia; Pitulescu, Mara E.; Adams, Ralf H.; Parrinello, Simona

    2014-01-01

    The vasculature is a prominent component of the subventricular zone neural stem cell niche. Although quiescent neural stem cells physically contact blood vessels at specialised endfeet, the significance of this interaction is not understood. In contrast, it is well established that vasculature-secreted soluble factors promote lineage progression of committed progenitors. Here we specifically investigated the role of cell-cell contact-dependent signalling in the vascular niche. Unexpectedly, we find that direct cell-cell interactions with endothelial cells enforces quiescence and promotes stem cell identity. Mechanistically, endothelial ephrinB2 and Jagged1 mediate these effects by suppressing cell-cycle entry downstream of mitogens and inducing stemness genes to jointly inhibit differentiation. In vivo, endothelial-specific ablation of either of the genes which encode these proteins, Efnb2 and Jag1 respectively, aberrantly activates quiescent stem cells, resulting in depletion. Thus, we identify the vasculature as a critical niche compartment for stem cell maintenance, furthering our understanding of how anchorage to the niche maintains stem cells within a pro-differentiative microenvironment. PMID:25283993

  14. What Turns Galaxies Off? the Different Morphologies of Star-Forming and Quiescent Galaxies Since z Approximates 2 from CANDELS

    Science.gov (United States)

    Bell, Eric F.; VanDerWel, Arjen; Papovich, Casey; Kocevski, Dale; Lotz, Jennifer; McIntosh, Daniel H.; Kartaltepe, Jeyhan; Faber, S. M.; Ferguson, Harry; Koekemoer, Anton; Grogin, Norman; Wuyts, Stijn; Cheung, Edmong; Conselice, Christopher J.; Dunlop, James S.; Giavalisco, Mauro; Herrington, Jessica; Koo, David; McGrath, Elizabeth J.; DeMello, Duilia; Rix, Hans-Walter; Robaina, Aday R.; Williams, Christina C.

    2011-01-01

    We use HST/WFC3 imaging from the CANDELS multicyc1e treasury survey, in conjunction with the Sloan Digital Sky Survey, to explore the evolution of galactic structure for galaxies with stellar masses > 3 x 10(exp 10) Solar Mass from Z= 2.2 to the present epoch, a time span of 10 Gyr. We explore the relationship between rest-frame optical color, stellar mass, star formation activity and the structural parameters of galaxies as determined from parametric fits to the surface brightness profiles of galaxies. We confirm the dramatic evolution from z= 2.2 to the present day in the number density of non-star-forming galaxies above 3 x 10(exp 10) Solar Mass reported by other authors. We find that the vast majority of these quiescent systems have concentrated light profiles, as parameterized by the Sersic index, and the population of concentrated galaxies grows similarly rapidly. We examine the joint distribution of star formation activity, Sersic index, stellar mass, mass divided by radius (a proxy for velocity dispersion), and stellar surface density. Quiescence correlates poorly with stellar mass at all z galaxy structure: while the vast majority of quiescent galaxies have prominent bulges, many of them have significant disks, and a number of bulge-dominated galaxies have significant star formation. Noting the rarity of quiescent galaxies without prominent bulges, we argue that a prominent bulge (and, perhaps by association, a supermassive black hole) is a necessary but not sufficient condition for quenching star formation on galactic scales over the last 10 Gyr; such a result is qualitatively consistent with the expectations of the AGN feedback paradigm.

  15. Quiescent thermal emission from neutron stars in LMXBs

    CERN Document Server

    Turlione, Anabela; Pons, José A

    2013-01-01

    The quiescent thermal emission from neutron stars in low mass X-ray binaries after active periods of intense activity in x-rays (outbursts) has been monitored. The theoretical modeling of the thermal relaxation of the neutron star crust may be used to establish constraints on the crust and envelope composition and transport properties, depending on the astrophysical scenarios assumed. We perform numerical simulations of the neutron star crust thermal evolution and compare them with inferred surface temperatures for five sources: MXB 1659-29, KS 1731-260, EXO 0748-676, XTE J1701-462 and IGR J17480-2446. We also present stationary envelope models to be used as a boundary condition for the crustal cooling models. We obtain a relation between the mass accretion rate and the temperature reached at the crust-envelope interface at the end of the active phase that accounts for early observations and reduces the number of free parameters of the problem. With this relation we are also able to set constraints to the env...

  16. Bubble entrapment during sphere impact onto quiescent liquid surfaces

    KAUST Repository

    Marston, Jeremy

    2011-06-20

    We report observations of air bubble entrapment when a solid sphere impacts a quiescent liquid surface. Using high-speed imaging, we show that a small amount of air is entrapped at the bottom tip of the impacting sphere. This phenomenon is examined across a broad range of impact Reynolds numbers, 0.2 a Re = (DU0/Il) a 1.2\\' 105. Initially, a thin air pocket is formed due to the lubrication pressure in the air layer between the sphere and the liquid surface. As the liquid surface deforms, the liquid contacts the sphere at a finite radius, producing a thin sheet of air which usually contracts to a nearly hemispherical bubble at the bottom tip of the sphere depending on the impact parameters and liquid properties. When a bubble is formed, the final bubble size increases slightly with the sphere diameter, decreases with impact speed but appears independent of liquid viscosity. In contrast, for the largest viscosities tested herein, the entrapped air remains in the form of a sheet, which subsequently deforms upon close approach to the base of the tank. The initial contact diameter is found to conform to scalings based on the gas Reynolds number whilst the initial thickness of the air pocket or adimplea scales with a Stokes\\' number incorporating the influence of the air viscosity, sphere diameter and impact speed and liquid density. © 2011 Cambridge University Press.

  17. Response of Quiescent Cerebral Cortical Astrocytes to Nanofibrillar Scaffold Properties

    Science.gov (United States)

    Ayres, Virginia; Mujdat Tiryaki, Volkan; Xie, Kan; Ahmed, Ijaz; Shreiber, David I.

    2013-03-01

    We present results of an investigation to examine the hypothesis that the extracellular environment can trigger specific signaling cascades with morphological consequences. Differences in the morphological responses of quiescent cerebral cortical astrocytes cultured on the nanofibrillar matrices versus poly-L-lysine functionalized glass and Aclar, and unfunctionalized Aclar surfaces were demonstrated using atomic force microscopy (AFM) and phalloidin staining of F-actin. The differences and similarities of the morphological responses were consistent with differences and similarities of the surface polarity and surface roughness of the four surfaces investigated in this work, characterized using contact angle and AFM measurements. The three-dimensional capability of AFM was also used to identify differences in cell spreading. An initial quantitative immunolabeling study further identified significant differences in the activation of the Rho GTPases: Cdc42, Rac1, and RhoA, which are upstream regulators of the observed morphological responses: filopodia, lamellipodia, and stress fiber formation. The results support the hypothesis that the extracellular environment can trigger preferential activation of members of the Rho GTPase family with demonstrable morphological consequences for cerebral cortical astrocytes. The support of NSF PHY-095776 is acknowledged.

  18. Spectral Energy Distribution of Markarian 501: Quiescent State Versus Extreme Outburst

    Science.gov (United States)

    Acciari, V. A.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Böttcher, M.; Boltuch, D.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Cannon, A.; Cesarini, A.; Ciupik, L.; Cui, W.; Dickherber, R.; Duke, C.; Errando, M.; Falcone, A.; Finley, J. P.; Finnegan, G.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Godambe, S.; Grube, J.; Guenette, R.; Gyuk, G.; Hanna, D.; Holder, J.; Huang, D.; Hui, C. M.; Humensky, T. B.; Imran, A.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Kieda, D.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Madhavan, A. S.; Maier, G.; McArthur, S.; McCann, A.; Moriarty, P.; Ong, R. A.; Otte, A. N.; Pandel, D.; Perkins, J. S.; Pichel, A.; Pohl, M.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Steele, D.; Swordy, S. P.; Theiling, M.; Thibadeau, S.; Varlotta, A.; Vassiliev, V. V.; Vincent, S.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Williams, D. A.; Wood, M.; Zitzer, B.; VERITAS Collaboration; Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Bordas, P.; Borla Tridon, D.; Bosch-Ramon, V.; Bose, D.; Braun, I.; Bretz, T.; Camara, M.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea del Pozo, E.; De Lotto, B.; De Maria, M.; De Sabata, F.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Errando, M.; Ferenc, D.; Fonseca, M. V.; Font, L.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giavitto, G.; Godinović, N.; Hadasch, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Kranich, D.; Krause, J.; La Barbera, A.; Leonardo, E.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Lorenz, E.; Majumdar, P.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moralejo, A.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; Paoletti, R.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pauss, F.; Pegna, R. G.; Perez-Torres, M. A.; Persic, M.; Peruzzo, L.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puchades, N.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rissi, M.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Sánchez-Conde, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sierpowska-Bartosik, A.; Sillanpää, A.; Sitarek, J.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Struebig, J. C.; Suric, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Vankov, H.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; MAGIC Collaboration; Paneque, D.; Hayashida, M.

    2011-03-01

    The very high energy (VHE; E > 100 GeV) blazar Markarian 501 (Mrk 501) has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Mrk 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Mrk 501 was coordinated in 2009 March, focusing around a multi-day observation with the Suzaku X-ray satellite and including γ-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Mrk 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of 1997 April 16, with the goal of examining variability of the spectral energy distribution (SED) between the two states. The derived broadband SED shows the characteristic double-peaked profile. We find that the X-ray peak shifts by over two orders of magnitude in photon energy between the two flux states while the VHE peak varies little. The limited shift in the VHE peak can be explained by the transition to the Klein-Nishina (KN) regime. Synchrotron self-Compton models are matched to the data and the implied KN effects are explored.

  19. Spectral Energy Distribution of Markarian 501: Quiescent State vs. Extreme Outburst

    CERN Document Server

    Acciari, V A; Aune, T; Beilicke, M; Benbow, W; Böttcher, M; Boltuch, D; Bradbury, S M; Buckley, J H; Bugaev, V; Cannon, A; Cesarini, A; Ciupik, L; Cui, W; Dickherber, R; Duke, C; Errando, M; Falcone, A; Finley, J P; Finnegan, G; Fortson, L; Furniss, A; Galante, N; Gall, D; Godambe, S; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Holder, J; Huang, D; Hui, C M; Humensky, T B; Imran, A; Kaaret, P; Karlsson, N; Kertzman, M; Kieda, D; Konopelko, A; Krawczynski, H; Krennrich, F; Madhavan, A S; Maier, G; McArthur, S; McCann, A; Moriarty, P; Ong, R A; Otte, A N; Pandel, D; Perkins, J S; Pichel, A; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Roache, E; Rose, H J; Schroedter, M; Sembroski, G H; Steele, D; Swordy, S P; Theiling, M; Thibadeau, S; Varlotta, A; Vassiliev, V V; Vincent, S; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; Weisgarber, T; Williams, D A; Wood, M; Zitzer, B; Aleksić, J; Antonelli, L A; Antoranz, P; Backes, M; Barrio, J A; Bastieri, D; González, J Becerra; Bednarek, W; Berdyugin, A; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Boller, A; Bonnoli, G; Bordas, P; Tridon, D Borla; Bosch-Ramon, V; Bose, D; Braun, I; Bretz, T; Camara, M; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Dazzi, F; De Angelis, A; del Pozo, E De Cea; De Lotto, B; De Maria, M; De Sabata, F; Mendez, C Delgado; Ortega, A Diago; Doert, M; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Elsaesser, D; Errando, M; Ferenc, D; Fonseca, M V; Font, L; López, R J García; Garczarczyk, M; Gaug, M; Giavitto, G; Godinović, N; Hadasch, D; Herrero, A; Hildebrand, D; Höhne-Mönch, D; Hose, J; Hrupec, D; Jogler, T; Klepser, S; Krähenbühl, T; Kranich, D; Krause, J; La Barbera, A; Leonardo, E; Lindfors, E; Lombardi, S; Longo, F; López, M; Lorenz, E; Majumdar, P; Makariev, M; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Miranda, J M; Mirzoyan, R; Miyamoto, H; Moldón, J; Moralejo, A; Nieto, D; Nilsson, K; Orito, R; Oya, I; Paoletti, R; Paredes, J M; Partini, S; Pasanen, M; Pauss, F; Pegna, R G; Perez-Torres, M A; Persic, M; Peruzzo, L; Pochon, J; Prada, F; Moroni, P G Prada; Prandini, E; Puchades, N; Puljak, I; Reichardt, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rissi, M; Rügamer, S; Saggion, A; Saito, K; Saito, T Y; Salvati, M; Sánchez-Conde, M; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shayduk, M; Shore, S N; Sierpowska-Bartosik, A; Sillanpää, A; Sitarek, J; Sobczynska, D; Spanier, F; Spiro, S; Stamerra, A; Steinke, B; Storz, J; Strah, N; Struebig, J C; Suric, T; Takalo, L; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Torres, D F; Vankov, H; Wagner, R M; Weitzel, Q; Zabalza, V; Zandanel, F; Zanin, R; Paneque, D; Hayashida, M

    2010-01-01

    The very high energy (VHE; E > 100 GeV) blazar Markarian 501 has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Markarian 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Markarian 501 was coordinated in March 2009, focusing around a multi-day observation with the Suzaku X-ray satellite and including {\\gamma}-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Markarian 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of April 16, 1997, with the goal of examining variability of the spectral energy distribution between the two states. The derived broadband spectral energy distribution shows the characteristic doub...

  20. DEM Measurements of Moving UV Features in Prominences

    Science.gov (United States)

    Oegerle, William (Technical Monitor); Kucera, T. A.; Landi, E.

    2003-01-01

    Multi-thermal features with speeds of 5-70 km/s perpendicular to the line of sight are common in the prominences which showed traceable motions. These speeds are noticeably higher than the typical speeds of 5-20 km/s observed in H-alpha data from "quiet" prominences and are more typical of "activated" prominences in which H-alpha blob speeds of up to 40 km/s have been reported. In order to make a more quantitative determination of the thermal properties of the moving features seen in the UV, we use the SOHO Cororial Diagnostic Spectrometer to take a time series of exposures from a single pointing position, providing a measurement of spectral line properties as a function of time and position along the slit. The resulting observations in lines of O III, O IV, O V, Ne IV, Ne V, Ne VI, and Ne VII allow us to calculate the differential emission measure of moving features and provide a test of models of flows in prominences.

  1. Thermal Properties of Moving UV Features in Prominences

    Science.gov (United States)

    Kucera, Therese A.

    2003-01-01

    Multi-thermal features with speeds of 5-70 kilometers per second perpendicular to the line of sight are common in the prominences which showed traceable motions. These speeds are noticeably higher than the typical speeds of 5-20 kilometers per second observed in H-alpha data from "quiet" prominences and are more typical of "activated" prominences in which H-alpha blob speeds of up to 40 kilometers per second have been reported. In order to make a more quantitative determination of the thermal properties of the moving features seen in the UV, we use the SOHO instruments SUMER and CDS to take a time series of exposures from a single pointing position, providing a measurement of spectral line properties as a function of time and position along the slit. The resulting observations in lines spectral lines in a range of "transition region" temperatures allow us to analyze the thermal properties of the moving prominence sources as a function of time.

  2. The first X-ray imaging spectroscopy of quiescent solar active regions with NuSTAR

    DEFF Research Database (Denmark)

    Hannah, Iain G.; Grefenstette, Brian W.; Smith, David M.

    2016-01-01

    We present the first observations of quiescent active regions (ARs) using the Nuclear Spectroscopic Telescope Array (NuSTAR), a focusing hard X-ray telescope capable of studying faint solar emission from high-temperature and non-thermal sources. We analyze the first directly imaged and spectrally...

  3. Discovery of Compact Quiescent Galaxies at Intermediate Redshifts in DEEP2

    Science.gov (United States)

    Blancato, Kirsten; Chilingarian, Igor; Damjanov, Ivana; Moran, Sean; Katkov, Ivan

    2015-01-01

    Compact quiescent galaxies in the redshift range 0.6 histories of these objects from the high redshift z ≥ 2 Universe to the local z ~ 0 Universe. We identify the first intermediate redshift compact quiescent galaxies by searching a sample of 1,089 objects in the DEEP2 Redshift Survey that have multi-band photometry, spectral fitting, and readily available structural parameters. We find 27 compact quiescent candidates between z = 0.6 and z = 1.1 where each candidate galaxy has archival Hubble Space Telescope (HST) imaging and is visually confirmed to be early-type. The candidates have half-light radii ranging from 0.83 2 which suggests these objects may be the relics of the observed high redshift compact galaxies and formation at z ≤ 2 which suggests there is an additional population of more recently formed massive compact galaxies. This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  4. Suppressing star formation in quiescent galaxies with supermassive black hole winds

    CERN Document Server

    Cheung, Edmond; Cappellari, Michele; Peirani, Sébastien; Rujopakarn, Wiphu; Westfall, Kyle; Yan, Renbin; Bershady, Matthew; Greene, Jenny E; Heckman, Timothy M; Drory, Niv; Law, David R; Masters, Karen L; Thomas, Daniel; Wake, David A; Weijmans, Anne-Marie; Rubin, Kate; Belfiore, Francesco; Vulcani, Benedetta; Chen, Yan-mei; Zhang, Kai; Gelfand, Joseph D; Bizyaev, Dmitry; Roman-Lopes, A; Schneider, Donald P

    2016-01-01

    Quiescent galaxies with little or no ongoing star formation dominate the galaxy population above $M_{*}\\sim 2 \\times 10^{10}~M_{\\odot}$, where their numbers have increased by a factor of $\\sim25$ since $z\\sim2$. Once star formation is initially shut down, perhaps during the quasar phase of rapid accretion onto a supermassive black hole, an unknown mechanism must remove or heat subsequently accreted gas from stellar mass loss or mergers that would otherwise cool to form stars. Energy output from a black hole accreting at a low rate has been proposed, but observational evidence for this in the form of expanding hot gas shells is indirect and limited to radio galaxies at the centers of clusters, which are too rare to explain the vast majority of the quiescent population. Here we report bisymmetric emission features co-aligned with strong ionized gas velocity gradients from which we infer the presence of centrally-driven winds in typical quiescent galaxies that host low-luminosity active nuclei. These galaxies ar...

  5. Topic Prominence in Chinese EFL Learners' Interlanguage

    Science.gov (United States)

    Li, Shaopeng; Yang, Lianrui

    2014-01-01

    The present study aims to investigate the general characteristics of topicprominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from a discourse perspective. Topic structures mainly appear in Chinese discourse in the form of topic chains (Wang, 2002; 2004). The…

  6. Bubble formation in a quiescent pool of gold nanoparticle suspension.

    Science.gov (United States)

    Vafaei, Saeid; Wen, Dongsheng

    2010-08-11

    This paper begins with an extensive review of the formation of gas bubbles, with a particular focus on the dynamics of triple lines, in a pure liquid and progresses into an experimental study of bubble formation on a micrometer-sized nozzle immersed in a quiescent pool of aqueous gold nanofluid. Unlike previous studies of triple line dynamics in a nanofluid under evaporation or boiling conditions, which are mainly caused by the solid surface modification due to particle sedimentation, this work focuses on the roles of nanoparticles suspended in the liquid phase. The experiments are conducted under a wide range of flow rates and nanoparticle concentrations, and many interesting phenomena are revealed. It is observed that nanofluids prevent the spreading of the triple line during bubble formation, i.e. the triple line is pinned somewhere around the middle of the tube wall during the rapid bubble formation stage whereas it spreads to the outer edge of the tube for pure water. A unique 'stick-slip' movement of the triple line is also observed for bubbles forming in nanofluids. At a given bubble volume, the radius of the contact line is found to be smaller for higher particle concentrations, but a reverse trend is found for the dynamic bubble contact angle. With the increase of particle concentration, the bubble frequency is raised and the bubble departure volume is decreased. The bubble shape is found to be in a good agreement with the prediction from Young-Laplace equation for given flow rates. The influence of nanoparticles on other detailed characteristics related to bubble growth inside, including the variation of bubble volume expansion rate, the radius of the curvature at the apex, the bubble height and bubble volume, is revealed. It is suggested that the variation of surface tensions and the resultant force balance at the triple line might be responsible for the modified dynamics of the triple line.

  7. Characterisation of plasma synthetic jet actuators in quiescent flow

    Science.gov (United States)

    Zong, Haohua; Kotsonis, Marios

    2016-08-01

    An experimental characterisation study of a large-volume three-electrode plasma synthetic jet actuator (PSJA) is presented. A sequential discharge power supply system is used to activate the PSJA. Phase-locked planar particle image velocimetry (PIV) and time-resolved Schlieren imaging are used to characterise the evolution of the induced flow field in quiescent flow conditions. The effect of orifice diameter is investigated. Results indicate three distinct features of the actuator-induced flow field. These are the initial shock waves, the high speed jet and vortex rings. Two types of shock waves with varied intensities, namely a strong shock wave and a weak shock wave, are issued from the orifice shortly after the ignition of the discharge. Subsequently, the emission of a high speed jet is observed, reaching velocities up to 130 m s-1. Pronounced oscillation of the exit velocity is caused by the periodical behaviour of capacitive discharge, which also led to the formation of vortex ring trains. Orifice diameter has no influence on the jet acceleration stage and the peak exit velocity. However, a large orifice diameter results in a rapid decline of the exit velocity and thus a short jet duration time. Vortex ring propagation velocities are measured at peak values ranging from 55 m s-1-70 m s-1. In the case of 3 mm orifice diameter, trajectory of the vortex ring severely deviates from the actuator axis of symmetry. The development of this asymmetry in the flow field is attributed to asymmetry in the electrode configuration.

  8. Modeling selective elimination of quiescent cancer cells from bone marrow.

    Science.gov (United States)

    Cavnar, Stephen P; Rickelmann, Andrew D; Meguiar, Kaille F; Xiao, Annie; Dosch, Joseph; Leung, Brendan M; Cai Lesher-Perez, Sasha; Chitta, Shashank; Luker, Kathryn E; Takayama, Shuichi; Luker, Gary D

    2015-08-01

    Patients with many types of malignancy commonly harbor quiescent disseminated tumor cells in bone marrow. These cells frequently resist chemotherapy and may persist for years before proliferating as recurrent metastases. To test for compounds that eliminate quiescent cancer cells, we established a new 384-well 3D spheroid model in which small numbers of cancer cells reversibly arrest in G1/G0 phase of the cell cycle when cultured with bone marrow stromal cells. Using dual-color bioluminescence imaging to selectively quantify viability of cancer and stromal cells in the same spheroid, we identified single compounds and combination treatments that preferentially eliminated quiescent breast cancer cells but not stromal cells. A treatment combination effective against malignant cells in spheroids also eliminated breast cancer cells from bone marrow in a mouse xenograft model. This research establishes a novel screening platform for therapies that selectively target quiescent tumor cells, facilitating identification of new drugs to prevent recurrent cancer. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Cyclical Variability of Prominences, CMEs and Flares

    Indian Academy of Sciences (India)

    J. L. Ballester

    2000-09-01

    Solar flares, prominences and CMEs are well known manifestations of solar activity. For many years, qualitative studies were made about the cyclical behaviour of such phenomena. Nowadays, more quantitative studies have been undertaken with the aim to understand the solar cycle dependence of such phenomena as well as peculiar behaviour, such as asymmetries and periodicities, occurring within the solar cycle. Here, we plan to review the more recent research concerning all these topics.

  10. 3D WHOLE-PROMINENCE FINE STRUCTURE MODELING. II. PROMINENCE EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Gunár, Stanislav; Mackay, Duncan H. [School of Mathematics and Statistics, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom)

    2015-10-20

    We use the new three-dimensional (3D) whole-prominence fine structure model to study the evolution of prominences and their fine structures in response to changes in the underlying photospheric magnetic flux distribution. The applied model combines a detailed 3D prominence magnetic field configuration with a realistic description of the prominence plasma distributed along multiple fine structures. In addition, we utilize an approximate Hα visualization technique to study the evolution of the visible cool prominence plasma both in emission (prominence) and absorption (filament). We show that the initial magnetic field configuration of the modeled prominence is significantly disturbed by the changing position of a single polarity of a magnetic bipole as the bipole is advected toward the main body of the filament. This leads to the creation of a barb, which becomes the dominant feature visible in the synthetic Hα images of both the prominence and filament views. The evolution of the bipole also creates conditions that lead to the disappearance and reappearance of large portions of the main body. We also show that an arch-like region containing a dark void (a bubble) can be naturally produced in the synthetic prominence Hα images. While not visible in terms of the magnetic field lines, it is due to a lack of Hα emission from low-pressure, low-density plasma located in shallow magnetic dips lying along the lines of sight intersecting the dark void. In addition, a quasi-vertical small-scale feature consisting of short and deep dips, piled one above the other, is produced.

  11. Prominence measurement of total solar eclipse: March 9th 2016, Ternate, Indonesia

    Science.gov (United States)

    Naufal, Luthfi; Abdan Malikul Mulki, Fargiza; Fatima, Siti; Widyanita; Zahirah, Saffanah; Dimas Satrya, Christoforus; Herdiwijaya, Dhani

    2016-11-01

    Prominence is a hot gas that consists of electrically charged particles, which is propelled outward Solar surface. It can happen when the activity of sunspot rising up. Ground- based observation of prominence is rather difficult due to the brightness of the Sun, which it needs appropriate method. During total solar eclipse (TSE), prominence is easier to observe. In Ternate, Maluku islands (0°4632.0"N 127°2305.7"E), we observed solar prominence in visual and infrared spectra performed by using regular-DSLR camera for visual wavelength and modified-DSLR (IR-cut filter removal) for infrared wavelength, respectively. Next, we calculated the length of prominence from TSE images, and found that the real minimum length of prominence in red is 1.05 times longer than green and blue ones. And, the real maximum length of prominence is 1.08 times longer than blue and 1.04 times longer than green. The intensity of red is brighter 1.37 times to green and 1.23 times to blue. The causes of the results due to the different temperatures of the prominences and the radiation from H-alpha emission. We succeeded to observe directly the prominence with simple cameras and measured its length and brightness.

  12. Massive Quiescent Disk Galaxies in the CANDELS survey

    Science.gov (United States)

    Kesseli, Aurora; McGrath, E. J.; CANDELS Collaboration

    2014-01-01

    Using data from the GOODS-S field of the CANDELS survey, we find evidence for an increasing fraction of disk-dominated galaxies at high-redshift ( 2) among the quiescent, or non-star-forming galaxy population, in agreement with a growing body of evidence from recent results in the literature. We selected all galaxies with mass M>1010 Msun within the redshift range 0.5 ≤ z ≤ 2.5, and imposed a two-color selection criteria using rest-frame U, V, and J-band flux to separate quiescent from star-forming galaxies. From this sample, we performed a qualitative visual classification and a quantitative classification using the galaxy-fitting program Galfit. Of the original 140 quiescent galaxies, 23 have a disk component that contributes 50% or more of the total integrated galaxy light, and most of these are at high-redshift. At a redshift of z ~ 2 a significant fraction of all quiescent galaxies showed strong disk components with 30% being disk-dominated. We also find that massive disk galaxies seem to live in less densely populated environments while massive ellipticals live in environments with more neighbors, which leads us to believe that there are two mechanisms for the creation of massive quiescent galaxies. For the disks, the lower density environment and the disk nature of these galaxies lead us to favor cold streams over the major merger model of galaxy formation. The ellipticals, which live in higher density environments, could be assembled through major mergers of already aged stellar populations (e.g., dry mergers). This research is supported by the Clare Boothe Luce Foundation.

  13. Detection of Prominent Stellar Disks in the Progenitors of Present-day Massive Elliptical Galaxies

    CERN Document Server

    Davari, Roozbeh H; Mobasher, Bahram; Canalizo, Gabriela

    2016-01-01

    Massive galaxies at higher redshifts ($\\emph{z}$ $>$ 2) show different characteristics from their local counterparts: They are compact and most likely have a disk. In this study, we trace the evolution of local massive galaxies by performing a detailed morphological analysis, namely, fitting single S\\'{e}rsic profiles and performing bulge+disk decompositions. We analyze $\\sim$ 250 massive galaxies selected from all CANDELS fields (COSMOS, UDS, EGS, GOODS-South and GOODS-North). We confirm that both star-forming and quiescent galaxies increase their sizes significantly from $\\emph{z}$ $\\approx$ 2.5 to the present day. The global S\\'{e}rsic index of quiescent galaxies increases over time (from $n$ $\\approx$ 2.5 to $n$ $>$ 4), while that of star-forming galaxies remains roughly constant ($n$ $\\approx$ 2.5). By decomposing galaxy profiles into bulge+disk components, we find that massive galaxies at high redshift have prominent stellar disks, which are also evident from visual inspection of the images. By $z$ $\\ap...

  14. STRUCTURE OF PROMINENCE LEGS: PLASMA AND MAGNETIC FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Levens, P. J.; Labrosse, N. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Schmieder, B. [Observatoire de Paris, Meudon, F-92195 (France); Ariste, A. López, E-mail: p.levens.1@research.gla.ac.uk [Institut de Recherche en Astrophysique et Planétologie, Toulouse (France)

    2016-02-10

    We investigate the properties of a “solar tornado” observed on 2014 July 15, and aim to link the behavior of the plasma to the internal magnetic field structure of the associated prominence. We made multi-wavelength observations with high spatial resolution and high cadence using SDO/AIA, the Interface Region Imaging Spectrograph (IRIS) spectrograph, and the Hinode/Solar Optical Telescope (SOT) instrument. Along with spectropolarimetry provided by the Télescope Héliographique pour l’Etude du Magnétisme et des Instabilités Solaires telescope we have coverage of both optically thick emission lines and magnetic field information. AIA reveals that the two legs of the prominence are strongly absorbing structures which look like they are rotating, or oscillating in the plane of the sky. The two prominence legs, which are both very bright in Ca ii (SOT), are not visible in the IRIS Mg ii slit-jaw images. This is explained by the large optical thickness of the structures in Mg ii, which leads to reversed profiles, and hence to lower integrated intensities at these locations than in the surroundings. Using lines formed at temperatures lower than 1 MK, we measure relatively low Doppler shifts on the order of ±10 km s{sup −1} in the tornado-like structure. Between the two legs we see loops in Mg ii, with material flowing from one leg to the other, as well as counterstreaming. It is difficult to interpret our data as showing two rotating, vertical structures that are unrelated to the loops. This kind of “tornado” scenario does not fit with our observations. The magnetic field in the two legs of the prominence is found to be preferentially horizontal.

  15. Twisting, Rolling Motions, and Helicity in Prominence Eruptions

    Science.gov (United States)

    McKillop, Sean; Miralles, Mari Paz; Murphy, Nicholas A.; McCauley, Patrick; Su, Yingna

    2015-04-01

    Panasenco et al. [1] report observations of several CMEs that display a rolling motion about the axis of the erupting prominence. Murphy et al. [2] present simulations of line-tied asymmetric magnetic reconnection that make a falsifiable prediction regarding the handedness of rolling motions of flux ropes during solar eruptions. Mass motions in prominence eruptions tend to be complicated and characterizing these motions is a challenge. We use the AIA filament eruption catalog [3] as a source for finding events. If rolling motions are detected then we will investigate the handedness prediction. We use magnetograms from HMI to determine the strength and asymmetric properties of the photospheric magnetic field in the regions of interest and will use AIA observations to determine the handedness of the rolling motions. We then compare the photospheric magnetic information with the handedness to determine if there is a relationship between the two. We also determine the chirality of the prominences to see if there is any interesting relationship to the twist, rolling motion and/or handedness of the roll.[1] O. Panasenco, S. Martin, A. D. Joshi, & N. Srivastava, J. Atmos. Sol.-Terr. Phys., 73, 1129 (2011)[2] N. A. Murphy, M. P. Miralles, C. L. Pope, J. C. Raymond, H. D. Winter, K. K. Reeves, D. B. Seaton, A. A. van Ballegooijen, & J. Lin, ApJ, 751, 56 (2012)[3] http://aia.cfa.harvard.edu/filament/

  16. A massive, quiescent galaxy at a redshift of 3.717

    Science.gov (United States)

    Glazebrook, Karl; Schreiber, Corentin; Labbé, Ivo; Nanayakkara, Themiya; Kacprzak, Glenn G.; Oesch, Pascal A.; Papovich, Casey; Spitler, Lee R.; Straatman, Caroline M. S.; Tran, Kim-Vy H.; Yuan, Tiantian

    2017-04-01

    Finding massive galaxies that stopped forming stars in the early Universe presents an observational challenge because their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep near-infrared surveys. These surveys have revealed the presence of massive, quiescent early-type galaxies appearing as early as redshift z ≈ 2, an epoch three billion years after the Big Bang. Their age and formation processes have now been explained by an improved generation of galaxy-formation models, in which they form rapidly at z ≈ 3-4, consistent with the typical masses and ages derived from their observations. Deeper surveys have reported evidence for populations of massive, quiescent galaxies at even higher redshifts and earlier times, using coarsely sampled photometry. However, these early, massive, quiescent galaxies are not predicted by the latest generation of theoretical models. Here we report the spectroscopic confirmation of one such galaxy at redshift z = 3.717, with a stellar mass of 1.7 × 1011 solar masses. We derive its age to be nearly half the age of the Universe at this redshift and the absorption line spectrum shows no current star formation. These observations demonstrate that the galaxy must have formed the majority of its stars quickly, within the first billion years of cosmic history in a short, extreme starburst. This ancestral starburst appears similar to those being found by submillimetre-wavelength surveys. The early formation of such massive systems implies that our picture of early galaxy assembly requires substantial revision.

  17. Measurement of Prominent eta Decay Branching Fractions

    CERN Document Server

    López, A; Méndez, H; Ramírez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Menaa, N; Mountain, R; Nisar, S; Randrianarivony, K; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Galik, R S; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A G; Ernst, J; Ecklund, K M; Severini, H; Love, W; Savinov, V

    2007-01-01

    The decay psi(2S) --> eta J/psi is used to measure, for the first time, all prominent eta-meson branching fractions with the same experiment in the same dataset, thereby providing a consistent treatment of systematics across branching fractions. We present results for eta decays to gamma gamma, pi+pi-pi0, 3 pi0, pi+ pi- gamma, and e+ e- gamma, accounting for 99.9% of all eta decays. The precisions for several of the branching fractions and their ratios are improved. Two channels, pi+ pi- gamma and e+ e- gamma, show results that differ at the level of three standard deviations from those previously determined.

  18. Constraining the neutron star equation of state using quiescent low-mass X-ray binaries

    CERN Document Server

    Jonker, P G

    2007-01-01

    Chandra or XMM-Newton observations of quiescent low-mass X-ray binaries can provide important constraints on the equation of state of neutron stars. The mass and radius of the neutron star can potentially be determined from fitting a neutron star atmosphere model to the observed X-ray spectrum. For a radius measurement it is of critical importance that the distance to the source is well constrained since the fractional uncertainty in the radius is at least as large as the fractional uncertainty in the distance. Uncertainties in modelling the neutron star atmosphere remain. At this stage it is not yet clear if the soft thermal component in the spectra of many quiescent X-ray binaries is variable on timescales too short to be accommodated by the cooling neutron star scenario. This can be tested with a long XMM-Newton observation of the neutron star X-ray transient CenX-4 in quiescence. With such an observation one can use the Reflection Grating Spectrometer spectrum to constrain the interstellar extinction to t...

  19. The quiescent phase of galactic disc growth

    Science.gov (United States)

    Aumer, Michael; Binney, James; Schönrich, Ralph

    2016-07-01

    We perform a series of controlled N-body simulations of growing disc galaxies within non-growing, live dark matter haloes of varying mass and concentration. Our initial conditions include either a low-mass disc or a compact bulge. New stellar particles are continuously added on near-circular orbits to the existing disc, so spiral structure is continuously excited. To study the effect of combined spiral and giant molecular cloud (GMC) heating on the discs, we introduce massive, short-lived particles that sample a GMC mass function. An isothermal gas component is introduced for a subset of the models. We perform a resolution study and vary parameters governing the GMC population, the histories of star formation and radial scale growth. Models with GMCs and standard values for the disc mass and halo density provide the right level of self-gravity to explain the age-velocity dispersion relation of the solar neighbourhood (Snhd). GMC heating generates remarkably exponential vertical profiles with scaleheights that are radially constant and agree with observations of galactic thin discs. GMCs are also capable of significantly delaying bar formation. The amount of spiral-induced radial migration agrees with what is required for the metallicity distribution of the Snhd. However, in our standard models, the outward-migrating populations are not hot enough vertically to create thick discs. Thick discs can form in models with high baryon fractions, but the corresponding bars are too long, the young stellar populations too hot and the discs flare considerably.

  20. The Impact of Surface Temperature Inhomogeneities on Quiescent Neutron Star Radius Measurements

    Science.gov (United States)

    Elshamouty, K. G.; Heinke, C. O.; Morsink, S. M.; Bogdanov, S.; Stevens, A. L.

    2016-08-01

    Fitting the thermal X-ray spectra of neutron stars (NSs) in quiescent X-ray binaries can constrain the masses and radii of NSs. The effect of undetected hot spots on the spectrum, and thus on the inferred NS mass and radius, has not yet been explored for appropriate atmospheres and spectra. A hot spot would harden the observed spectrum, so that spectral modeling tends to infer radii that are too small. However, a hot spot may also produce detectable pulsations. We simulated the effects of a hot spot on the pulsed fraction and spectrum of the quiescent NSs X5 and X7 in the globular cluster 47 Tucanae, using appropriate spectra and beaming for hydrogen atmosphere models, incorporating special and general relativistic effects, and sampling a range of system angles. We searched for pulsations in archival Chandra HRC-S observations of X5 and X7, placing 90% confidence upper limits on their pulsed fractions below 16%. We use these pulsation limits to constrain the temperature differential of any hot spots, and to then constrain the effects of possible hot spots on the X-ray spectrum and the inferred radius from spectral fitting. We find that hot spots below our pulsation limit could bias the spectroscopically inferred radius downward by up to 28%. For Cen X-4 (which has deeper published pulsation searches), an undetected hot spot could bias its inferred radius downward by up to 10%. Improving constraints on pulsations from quiescent LMXBs may be essential for progress in constraining their radii.

  1. Sub-millimeter galaxies as progenitors of compact quiescent galaxies

    CERN Document Server

    Toft, S; Magnelli, B; Karim, A; Zirm, A; Michalowski, M; Capak, P; Sheth, K; Schawinski, K; Krogager, J -K; Wuyts, S; Sanders, D; Man, A W S; Lutz, D; Staguhn, J; Berta, S; Mccracken, H; Krpan, J; Riechers, D

    2014-01-01

    Three billion years after the big bang (at redshift z=2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3quiescent galaxies at z=2 and a statistically well-understood sample of SMGs, we show that z=3-6 SMGs are consistent with being the progenitors of z=2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses and internal velocities. As...

  2. The evolution of star formation histories of quiescent galaxies

    CERN Document Server

    Pacifici, Camilla; Weiner, Benjamin J; Holden, Bradford; Gardner, Jonathan P; Faber, Sandra M; Ferguson, Henry C; Koo, David C; Primack, Joel R; Bell, Eric F; Dekel, Avishai; Gawiser, Eric; Giavalisco, Mauro; Rafelski, Marc; Simons, Raymond C; Barro, Guillermo; Croton, Darren J; Dave, Romeel; Fontana, Adriano; Grogin, Norman A; Koekemoer, Anton M; Lee, Seong-Kook; Salmon, Brett; Somerville, Rachel; Behroozi, Peter

    2016-01-01

    Although there has been much progress in understanding how galaxies evolve, we still do not understand how and when they stop forming stars and become quiescent. We address this by applying our galaxy spectral energy distribution models, which incorporate physically motivated star formation histories (SFHs) from cosmological simulations, to a sample of quiescent galaxies at $0.2quiescent galaxies with multi-band photometry spanning rest-frame ultraviolet through near-infrared wavelengths are selected from the CANDELS dataset. We compute median SFHs of these galaxies in bins of stellar mass and redshift. At all redshifts and stellar masses, the median SFHs rise, reach a peak, and then decline to reach quiescence. At high redshift, we find that the rise and decline are fast, as expected because the Universe is young. At low redshift, the duration of these phases depends strongly on stellar mass. Low-mass galaxies ($\\log(M_{\\ast}/M_{\\odot})\\sim9.5$) grow on average slowly, take a lo...

  3. 3D Reconstruction of a Rotating Erupting Prominence

    Science.gov (United States)

    Thompson, W. T.; Kliem, B.; Toeroek, T.

    2011-01-01

    A bright prominence associated with a coronal mass ejection (CME) was seen erupting from the Sun on 9 April 2008. This prominence was tracked by both the Solar Terrestrial Relations Observatory (STEREO) EUVI and COR1 telescopes, and was seen to rotate about the line of sight a it erupted; therefore, the event has been nicknamed the "Cartwheel CME." The threads of the prominence in the core of the CME quite clearly indicate the structure of a weakly to moderately twisted flux rope throughout the field of view, up to heliocentric heights of 4 solar radii. Although the STEREO separation was 48 deg, it was possible to match some sharp features in the later part of the eruption as seen in the 304 A line in EUVI and in the H-alpha-sensitive bandpass of COR I by both STEREO Ahead and Behind. These features could then be traced out in three-dimensional space, and reprojected into a view in which the eruption is directed toward the observer. The reconstructed view shows that the alignment of the prominence to the vertical axis rotates as it rises up to a leading-edge height of approximately equal to 2.5 solar radii, and then remains approximately constant. The alignment at 2.5 solar radii differs by about 115 deg from the original filament orientation inferred from H-alpha and EUV data, and the height profile of the rotation, obtained here for the first time, shows that two thirds of the total rotation are reached within approximately equal to 0.5 solar radii above the photosphere. These features are well reproduced by numerical simulations of an unstable moderately twisted flux rope embedded in external flux with a relatively strong shear field component.

  4. Pre-eruption Oscillations in Thin and Long Features in a Quiescent Filament

    Science.gov (United States)

    Joshi, Anand D.; Hanaoka, Yoichiro; Suematsu, Yoshinori; Morita, Satoshi; Yurchyshyn, Vasyl; Cho, Kyung-Suk

    2016-12-01

    We investigate the eruption of a quiescent filament located close to an active region. Large-scale activation was observed in only half of the filament in the form of pre-eruption oscillations. Consequently only this half erupted nearly 30 hr after the oscillations commenced. Time-slice diagrams of 171 Å images from the Atmospheric Imaging Assembly were used to study the oscillations. These were observed in several thin and long features connecting the filament spine to the chromosphere below. This study traces the origin of such features and proposes their possible interpretation. Small-scale magnetic flux cancellation accompanied by a brightening was observed at the footpoint of the features shortly before their appearance, in images recorded by the Helioseismic and Magnetic Imager. A slow rise of the filament was detected in addition to the oscillations, indicating a gradual loss of equilibrium. Our analysis indicates that a change in magnetic field connectivity between two neighbouring active regions and the quiescent filament resulted in a weakening of the overlying arcade of the filament, leading to its eruption. It is also suggested that the oscillating features are filament barbs, and the oscillations are a manifestation during the pre-eruption phase of the filaments.

  5. Formation and Evolution of a Multi-Threaded Prominence

    Science.gov (United States)

    Luna, M.; Karpen, J. T.; DeVore, C. R.

    2012-01-01

    We investigate the process of formation and subsequent evolution of prominence plasma in a filament channel and its overlying arcade. We construct a three-dimensional time-dependent model of a filament-channel prominence suitable to be compared with observations. We combine this magnetic field structure with one-dimensional independent simulations of many flux tubes. The magnetic structure is a three-dimensional sheared double arcade, and the thermal non-equilibrium process governs the plasma evolution. We have found that the condensations in the corona can be divided into two populations: threads and blobs. Threads are massive condensations that linger in the field line dips. Blobs are ubiquitous small condensations that are produced throughout the filament and overlying arcade magnetic structure, and rapidly fall to the chromosphere. The total prominence mass is in agreement with observations. The threads are the principal contributors to the total mass, whereas the blob contribution is small. The motion of the threads is basically horizontal, while blobs move in all directions along the field. The peak velocities for both populations are comparable, but there is a weak tendency for the velocity to increase with the inclination, and the blobs with motion near vertical have the largest values of the velocity. We have generated synthetic images of the whole structure in an H proxy and in two EUV channels of the AIA instrument aboard SDO. These images show the plasma at cool, warm and hot temperatures. The theoretical differential emission measure of our system agrees very well with observations in the temperature range log T = 4.6-5.7. We conclude that the sheared-arcade magnetic structure and plasma dynamics fit well the abundant observational evidence.

  6. Are tornado-like magnetic structures able to support solar prominence plasma?

    CERN Document Server

    Luna, Manuel; Priest, Eric

    2015-01-01

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloida...

  7. Suppressing star formation in quiescent galaxies with supermassive black hole winds

    Science.gov (United States)

    Cheung, Edmond; Bundy, Kevin; SDSS-IV/MaNGA

    2016-01-01

    In the last 10 billion years (i.e., since redshift z ~2) the number of quiescent galaxies with little to no ongoing star formation has grown by a factor ~25. This is challenging to understand since galaxy formation models predict that these galaxies will continue to accrete fresh gas over their lifetimes, relatively little of which is required to reignite measurable star formation. It is thought that feedback from fresh gas accreting onto a central active galactic nucleus (AGN) might help such galaxies maintain their quiescence, but observational evidence for such ``maintenance mode feedback'' remains sparse. Using novel imaging spectroscopy from the SDSS-IV MaNGA Survey (Sloan Digital Sky Survey IV: Mapping Nearby Galaxies at Apache Point Observatory), we present evidence for a new maintenance mode phenomenon we term ``red geysers,'' a potentially episodic but relatively low-power AGN driven wind present in typical quiescent field galaxies of moderate mass and spheroidal morphology. We examine an archetypal red geyser that appears to be accreting gas from a low-mass companion but has no corresponding star formation. Instead, we find evidence for a galaxy-scale ionized wind with outflow velocities reaching more than 300 km/s and high velocity dispersions. We also detect a narrow biconical pattern of strong emission line equivalent widths consistent with fast shocks. Given additional confirmation of a radio AGN present in the galaxy, we propose that red geysers such as this may be a common mode in which gas accretion activates an ionized wind feedback mechanism that prevents star formation and helps moderate luminosity quiescent galaxies maintain their quiescence.

  8. Distinct cell stress responses induced by ATP restriction in quiescent human fibroblasts

    Directory of Open Access Journals (Sweden)

    Nirupama Yalamanchili

    2016-10-01

    Full Text Available Quiescence is the prevailing state of many cell types under homeostatic conditions. Yet, surprisingly little is known about how quiescent cells respond to energetic and metabolic challenges. To better understand compensatory responses of quiescent cells to metabolic stress, we established, in human primary dermal fibroblasts, an experimental ‘energy restriction’ model. Quiescence was achieved by short-term culture in serum-deprived media and ATP supply restricted using a combination of glucose transport inhibitors and mitochondrial uncouplers. In aggregate, these measures led to markedly reduced intracellular ATP levels while not compromising cell viability over the observation period of 48 h. Analysis of the transcription factor landscape induced by this treatment revealed alterations in several signal transduction nodes beyond the expected biosynthetic adaptations. These included increased abundance of NF-κB regulated transcription factors and altered transcription factor subsets regulated by Akt and p53. The observed changes in gene regulation and corresponding alterations in key signaling nodes are likely to contribute to cell survival at intracellular ATP concentrations substantially below those achieved by growth factor deprivation alone. This experimental model provides a benchmark for the investigation of cell survival pathways and related molecular targets that are associated with restricted energy supply associated with biological aging and metabolic diseases.

  9. The impact of surface temperature inhomogeneities on quiescent neutron star radius measurements

    CERN Document Server

    Elshamouty, K; Morsink, S; Bogdanov, S; Stevens, A

    2016-01-01

    Fitting the thermal X-ray spectra of neutron stars (NSs) in quiescent X-ray binaries can constrain the masses and radii of NSs. The effect of undetected hot spots on the spectrum, and thus on the inferred NS mass and radius, has not yet been explored for appropriate atmospheres and spectra. A hot spot would harden the observed spectrum, so that spectral modeling tends to infer radii that are too small. However, a hot spot may also produce detectable pulsations. We simulated the effects of a hot spot on the pulsed fraction and spectrum of the quiescent NSs X5 and X7 in the globular cluster 47 Tucanae, using appropriate spectra and beaming for hydrogen atmosphere models, incorporating special and general relativistic effects, and sampling a range of system angles. We searched for pulsations in archival Chandra HRC-S observations of X5 and X7, placing 90\\% confidence upper limits on their pulsed fractions below 16\\%. We use these pulsation limits to constrain the temperature differential of any hot spots, and to...

  10. Rolling Motions During Solar Prominence Eruptions in Asymmetric Magnetic Environments

    Science.gov (United States)

    McKillop, Sean; Miralles, Mari Paz; Murphy, Nicholas Arnold; McCauley, Patrick

    2014-06-01

    Panasenco et al. [1] report observations of several CMEs that display a rolling motion about the axis of the erupting prominence. Murphy et al. [2] present simulations of line-tied asymmetric magnetic reconnection that make a falsifiable prediction regarding the handedness of rolling motions of flux ropes during solar eruptions. We will present initial results of our work to investigate this prediction. To determine the strength and any asymmetric properties of the magnetic field in the regions of interest in the photosphere, we use magnetograms from HMI. We use AIA observations to determine if there is any rolling motion and, if so, what handedness the rolling motions have. We then compare the photospheric magnetic information with the handedness information to determine if there is any relationship between the two. Finally, we will discuss prospects for diagnosing rolling motions of erupting prominence using off-limb IRIS observations.[1] O. Panasenco, S. Martin, A. D. Joshi, & N. Srivastava, J. Atmos. Sol.-Terr. Phys., 73, 1129 (2011)[2] N. A. Murphy, M. P. Miralles, C. L. Pope, J. C. Raymond, H. D. Winter, K. K. Reeves, D. B. Seaton, A. A. van Ballegooijen, & J. Lin, ApJ, 751, 56 (2012)

  11. The Quiescent Neutron Star and Hierarchical Triple: 4U 2129+47

    Science.gov (United States)

    Nowak, Michael; Wilms, Joern; Kühnel, Matthias; Chakrabarty, Deepto

    2017-08-01

    After a period of active accretion, neutron stars can enter a phase where their X-ray emission is dominated by thermal emission from their surface. The rate of cooling of this emission can yield insight into neutron star structure. Furthermore, emission models may help determine the neutron star radius. A number of questions arise when modeling such X-ray spectra as observed by Chandra or XMM-Newton. Is there ongoing, low level active accretion that is contributing to the observed soft X-ray emission? In a number of cases, a hard X-ray tail is also observed. What is the origin of this hard tail? The quiescent neutron star system 4U 2129+47 presents a unique opportunity to study these questions. This system is viewed nearly edge on, as evidenced by a periodic, total eclipse that lasts 1585 seconds out of the 5.24 hour orbit. As we are viewing this system edge on, both observed neutral column variations and an observed hard X-ray tail in year 2000 Chandra observations indicated ongoing active accretion. Subsequent XMM and Chandra observations over the next 15 years showed that both the neutral column variability and the hard X-ray tail vanished. Thus, these later observations may represent a true quiescent, cooling neutron star state. We assess the evidence for cooling in the 4U 2129+47 system. Furthermore, we use the timing of the X-ray eclipses to discuss evidence for a third body in the system, and derive likely orbital periods. Finally, we discuss how future X-ray missions, e.g., Athena and Lynx, could place more stringent limits on neutron star cooling and the presence of a hard tail (i.e., active accretion) in this system.

  12. A low-level accretion flare during the quiescent state of the neutron-star X-ray transient SAX J1750.8-2900

    NARCIS (Netherlands)

    Wijnands, R.; Degenaar, N.

    2013-01-01

    We report on a series of Swift/X-ray telescope observations, performed between 2012 February and 22 March, during the quiescent state of the neutron-star X-ray binary SAX J1750.8−2900. In these observations, the source was either just detected or undetected, depending on the exposure length (which r

  13. Gastrointestinal stromal tumor presenting with prominent calcification

    Institute of Scientific and Technical Information of China (English)

    Naoki Izawa; Takeshi Sawada; Ryuichi Abiko; Daisuke Kumon; Mami Hirakawa; Mika Kobayashi; Nobuyuki Obinata

    2012-01-01

    We present a rare case of a gastrointestinal stromal tumor (GIST) in the stomach with prominent calcification at presentation.A 61-year-old woman visited our hospital because of epigastric discomfort.A spherical calcified lesion with a diameter of about 30 mm was incidentally shown in the left upper quadrant on an abdominal X-ray.Computed tomography demonstrated that the tumor was growing from the upper gastric body,with calcification in the peripheral ring area.A laparoscopic partial gastrectomy was performed,and the resected specimen revealed a well-circumscribed tumor with exophytic growth from the gastric muscularis propria.Microscopic examination revealed spindleshaped tumor cells with calcification and hemorrhage.Additionally,positive immunoreactivity of the tumor to KIT and CD34 and a low mitotic index resulted in the diagnosis of very low risk GIST.There are a few case reports of heavily calcified GIST,although solitary or punctate calcification of primary GIST has been reported in several case series.Dystrophic calcification of necrotic or degenerative tissue is the supposed cause of primary calcified GISTs.In contrast,appearance of calcification after administration of imatinib mesylate,which may be one indicator of disease response,is possibly caused by a different mechanism.

  14. Submillimeter galaxies as progenitors of compact quiescent galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Toft, S.; Zirm, A.; Krogager, J.-K.; Man, A. W. S. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark); Smolčić, V.; Krpan, J. [Physics Department, University of Zagreb, Bijenička cesta 32, 10002 Zagreb (Croatia); Magnelli, B.; Karim, A. [Argelander Institute for Astronomy, Auf dem Hügel 71, Bonn, D-53121 (Germany); Michalowski, M. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Capak, P. [Spitzer Science Center, 314-6 Caltech, 1201 East California Boulevard, Pasadena, CA 91125 (United States); Sheth, K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Schawinski, K. [ETH Zurich, Institute for Astronomy, Department of Physics, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Wuyts, S.; Lutz, D.; Staguhn, J.; Berta, S. [MPE, Postfach 1312, D-85741 Garching (Germany); Sanders, D. [Institute for Astronomy, 2680 Woodlawn Drive, University of Hawaii, Honolulu, HI 96822 (United States); Mccracken, H. [Institut dAstrophysique de Paris, UMR7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Riechers, D., E-mail: sune@dark-cosmology.dk [Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)

    2014-02-20

    Three billion years after the big bang (at redshift z = 2), half of the most massive galaxies were already old, quiescent systems with little to no residual star formation and extremely compact with stellar mass densities at least an order of magnitude larger than in low-redshift ellipticals, their descendants. Little is known about how they formed, but their evolved, dense stellar populations suggest formation within intense, compact starbursts 1-2 Gyr earlier (at 3 < z < 6). Simulations show that gas-rich major mergers can give rise to such starbursts, which produce dense remnants. Submillimeter-selected galaxies (SMGs) are prime examples of intense, gas-rich starbursts. With a new, representative spectroscopic sample of compact, quiescent galaxies at z = 2 and a statistically well-understood sample of SMGs, we show that z = 3-6 SMGs are consistent with being the progenitors of z = 2 quiescent galaxies, matching their formation redshifts and their distributions of sizes, stellar masses, and internal velocities. Assuming an evolutionary connection, their space densities also match if the mean duty cycle of SMG starbursts is 42{sub −29}{sup +40} Myr (consistent with independent estimates), which indicates that the bulk of stars in these massive galaxies were formed in a major, early surge of star formation. These results suggest a coherent picture of the formation history of the most massive galaxies in the universe, from their initial burst of violent star formation through their appearance as high stellar-density galaxy cores and to their ultimate fate as giant ellipticals.

  15. Stellar dynamo models with prominent surface toroidal fields

    CERN Document Server

    Bonanno, Alfio

    2016-01-01

    Recent spectro-polarimetric observations of solar-type stars have shown the presence of photospheric magnetic fields with a predominant toroidal component. If the external field is assumed to be current-free it is impossible to explain these observations within the framework of standard mean-field dynamo theory. In this work it will be shown that if the coronal field of these stars is assumed to be harmonic, the underlying stellar dynamo mechanism can support photospheric magnetic fields with a prominent toroidal component even in the presence of axisymmetric magnetic topologies. In particular it is argued that the observed increase in the toroidal energy in low mass fast rotating stars can be naturally explained with an underlying $\\alpha\\Omega$ mechanism.

  16. Stellar Dynamo Models with Prominent Surface Toroidal Fields

    Science.gov (United States)

    Bonanno, Alfio

    2016-12-01

    Recent spectro-polarimetric observations of solar-type stars have shown the presence of photospheric magnetic fields with a predominant toroidal component. If the external field is assumed to be current-free it is impossible to explain these observations within the framework of standard mean-field dynamo theory. In this work, it will be shown that if the coronal field of these stars is assumed to be harmonic, the underlying stellar dynamo mechanism can support photospheric magnetic fields with a prominent toroidal component even in the presence of axisymmetric magnetic topologies. In particular, it is argued that the observed increase in the toroidal energy in low-mass fast-rotating stars can be naturally explained with an underlying αΩ mechanism.

  17. Physics of Solar Prominences: I-Spectral Diagnostics and Non-LTE Modelling

    Science.gov (United States)

    Labrosse, N.; Heinzel, P.; Vial, J.-C,; Kucera, T.; Parenti, S.; Gunar, S.; Schmieder, B.; Kilper, G.

    2010-01-01

    This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE (i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the prominence plasma in both its cool core and the hotter prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the prominence plasma and to the determination of prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex

  18. SPECTRO-POLARIMETRIC IMAGING REVEALS HELICAL MAGNETIC FIELDS IN SOLAR PROMINENCE FEET

    Energy Technology Data Exchange (ETDEWEB)

    González, M. J. Martínez; Sainz, R. Manso; Ramos, A. Asensio; Beck, C.; Díaz, A. J. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Rodríguez, J. de la Cruz [Institute for Solar Physics, Department of Astronomy, Stockholm University, Albanova University Center, SE-10691 Stockholm (Sweden)

    2015-03-20

    Solar prominences are clouds of cool plasma levitating above the solar surface and insulated from the million-degree corona by magnetic fields. They form in regions of complex magnetic topology, characterized by non-potential fields, which can evolve abruptly, disintegrating the prominence and ejecting magnetized material into the heliosphere. However, their physics is not yet fully understood because mapping such complex magnetic configurations and their evolution is extremely challenging, and must often be guessed by proxy from photometric observations. Using state-of-the-art spectro-polarimetric data, we reconstruct the structure of the magnetic field in a prominence. We find that prominence feet harbor helical magnetic fields connecting the prominence to the solar surface below.

  19. Settling of an asymmetric dumbbell in a quiescent fluid

    CERN Document Server

    Candelier, F

    2015-01-01

    We compute the hydrodynamic torque on a dumbbell (two spheres linked by a massless rigid rod) settling in a quiescent fluid at small but finite Reynolds number. The spheres have the same mass densities but different sizes. When the sizes are quite different the dumbbell settles vertically, the largest sphere first. But when the size difference is sufficiently small then its steady-state angle is determined by a competition between the size difference and the Reynolds number. When the sizes of the spheres are exactly equal we recover a result derived by Khayat & Cox (1989) for slender bodies: the dumbbell settles horizontally owing to fluid inertia effects.

  20. Colours, star formation rates and environments of star-forming and quiescent galaxies at the cosmic noon

    Science.gov (United States)

    Feldmann, Robert; Quataert, Eliot; Hopkins, Philip F.; Faucher-Giguère, Claude-André; Kereš, Dušan

    2017-09-01

    We analyse the star formation rates (SFRs), colours and dust extinctions of galaxies in massive (1012.5 - 1013.5 M⊙) haloes at z ∼ 2 in high-resolution, cosmological zoom-in simulations as part of the Feedback In Realistic Environments (FIRE) project. The simulations do not model feedback from active galactic nuclei (AGNs) but reproduce well the observed relations between stellar and halo mass and between stellar mass and SFR. About half (a third) of the simulated massive galaxies (massive central galaxies) at z ∼ 2 have broad-band colours classifying them as 'quiescent', and the fraction of quiescent centrals is steeply decreasing towards higher redshift, in agreement with observations. The progenitors of z ∼ 2 quiescent central galaxies are, on average, more massive, have lower specific SFRs and reside in more massive haloes than the progenitors of similarly massive star-forming centrals. The simulations further predict a morphological mix of galaxies that includes disc-dominated, irregular and early-type galaxies. However, our simulations do not reproduce the reddest of the quiescent galaxies observed at z ∼ 2. We also do not find evidence for a colour bimodality, but are limited by our modest sample size. In our simulations, the star formation activity of central galaxies of moderate mass (Mstar ∼ 1010 - 1011 M⊙) is affected by a combination of two distinct physical processes. Outflows powered by stellar feedback result in a short-lived (experience a moderate reduction of their SFRs ('cosmological starvation'). The relative importance of these processes and AGN feedback is uncertain and will be explored in future work.

  1. Three-Dimensional Morphology of a Coronal Prominence Cavity

    Science.gov (United States)

    Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hill, S.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Rachmeler, L.; Reeves, K. K.; Schmieder, B.; Schmit, D. J.; Seaton, D. B.; Sterling, A. C.; Tripathi, D.; Williams, D. R.; Zhang, M.

    2010-01-01

    We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft-X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally-extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step towards quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager (EUVI) observations from the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explains the observed variation in cavity visibility for the east vs. west limbs

  2. Timing the Evolution of Quiescent and Star-forming Local Galaxies

    Science.gov (United States)

    Pacifici, Camilla; Oh, Sree; Oh, Kyuseok; Lee, Jaehyun; Yi, Sukyoung K.

    2016-06-01

    Constraining the star formation histories (SFHs) of individual galaxies is crucial for understanding the mechanisms that regulate their evolution. Here, we combine multi-wavelength (ultraviolet, optical, and infrared) measurements of a very large sample of galaxies (˜230,000) at z motivated models of galaxy spectral energy distributions to extract constraints on galaxy physical parameters (such as stellar mass and star formation rate) as well as individual SFHs. In particular, we set constraints on the timescales in which galaxies form a certain percentage of their total stellar mass (namely, 10%, 50%, and 90%). The large statistics allows us to average such measurements over different populations of galaxies (quiescent and star-forming) and in narrow ranges of stellar mass. As in the downsizing scenario, we confirm that low-mass galaxies have more extended SFHs than high-mass galaxies. We also find that at the same observed stellar mass, galaxies that are now quiescent evolve more rapidly than galaxies that are currently still forming stars. This suggests that stellar mass is not the only driver of galaxy evolution, but plays along with other factors such as merger events and other environmental effects.

  3. Timing the evolution of quiescent and star-forming local galaxies

    CERN Document Server

    Pacifici, Camilla; Oh, Kyuseok; Lee, Jaehyun; Yi, Sukyoung K

    2016-01-01

    Constraining the star formation histories (SFHs) of individual galaxies is crucial to understanding the mechanisms that regulate their evolution. Here, we combine multi-wavelength (ultraviolet, optical, and infrared) measurements of a very large sample of galaxies (~230,000) at z<0.16, with physically motivated models of galaxy spectral energy distributions to extract constraints on galaxy physical parameters (such as stellar mass and star formation rate) as well as individual SFHs. In particular, we set constraints on the timescales in which galaxies form a certain percentage of their total stellar mass (namely, 10, 50 and 90%). The large statistics allows us to average such measurements over different populations of galaxies (quiescent and star-forming) and in narrow ranges of stellar mass. As in the downsizing scenario, we confirm that low-mass galaxies have more extended SFHs than high-mass galaxies. We also find that at the same observed stellar mass, galaxies that are now quiescent evolve more rapidl...

  4. EXPLORING THE z = 3-4 MASSIVE GALAXY POPULATION WITH ZFOURGE: THE PREVALENCE OF DUSTY AND QUIESCENT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Spitler, Lee R.; Rees, Glen [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Straatman, Caroline M. S.; Labbé, Ivo [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Glazebrook, Karl; Kacprzak, Glenn G.; Nanayakkara, Themiya [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Tran, Kim-Vy H.; Papovich, Casey; Kawinwanichakij, Lalitwadee; Mehrtens, Nicola; Tilvi, Vithal; Tomczak, Adam R. [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); Quadri, Ryan F.; Persson, S. Eric; Kelson, Daniel D.; McCarthy, Patrick J.; Monson, Andrew J. [Carnegie Observatories, Pasadena, CA 91101 (United States); Van Dokkum, Pieter [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Allen, Rebecca, E-mail: lee.spitler@mq.edu.au [Australian Astronomical Observatory, P.O. Box 296 Epping, NSW 1710 (Australia)

    2014-06-01

    Our understanding of the redshift z > 3 galaxy population relies largely on samples selected using the popular ''dropout'' technique, typically consisting of UV-bright galaxies with blue colors and prominent Lyman breaks. As it is currently unknown if these galaxies are representative of the massive galaxy population, we here use the FOURSTAR Galaxy Evolution (ZFOURGE) survey to create a stellar mass-limited sample at z = 3-4. Uniquely, ZFOURGE uses deep near-infrared medium-bandwidth filters to derive accurate photometric redshifts and stellar population properties. The mass-complete sample consists of 57 galaxies with log M >10.6, reaching below M {sup *} at z = 3-4. On average, the massive z = 3-4 galaxies are extremely faint in the observed optical with median R{sub tot}{sup AB}=27.48±0.41 (rest-frame M {sub 1700} = –18.05 ± 0.37). They lie far below the UV luminosity-stellar mass relation for Lyman break galaxies and are about ∼100 × fainter at the same mass. The massive galaxies are red (R – K {sub s} {sub AB} = 3.9 ± 0.2; rest-frame UV-slope β = –0.2 ± 0.3) likely from dust or old stellar ages. We classify the galaxy spectral energy distributions by their rest-frame U–V and V–J colors and find a diverse population: 46{sub −6−17}{sup +6+10}% of the massive galaxies are quiescent, 40{sub −6−5}{sup +6+7}% are dusty star-forming galaxies, and only 14{sub −3−4}{sup +3+10}% resemble luminous blue star-forming Lyman break galaxies. This study clearly demonstrates an inherent diversity among massive galaxies at higher redshift than previously known. Furthermore, we uncover a reservoir of dusty star-forming galaxies with 4 × lower specific star-formation rates compared to submillimeter-selected starbursts at z > 3. With 5 × higher numbers, the dusty galaxies may represent a more typical mode of star formation compared to submillimeter-bright starbursts.

  5. Incidencia de infecciones quiescentes de Botrytis cinerea en flores y

    Directory of Open Access Journals (Sweden)

    MolinaG. Gilma Sandra

    2004-12-01

    Full Text Available

    Se aisló Botrytis cinerea de flores y frutos asintomáticos de mora de castilla ( Rubus glaucus Benth. en  seis estados fenológicos desde botón cerrado hasta fruto maduro. Estas infecciones quiescentes ocurrieron raramente en botones florales cerrados, pero cuando éstos abren las estructuras florales aparecen colonizadas. La alta frecuencia de infecciones quiescentes en frutos en desarrollo y frutos maduros es atribuible a infecciones tempranas en estructuras florales. Inoculaciones hechas con conidias de B. cinerea marcadas con calcofluor produjeron infecciones en todos los estados fenológicos; la germinación de conidias en los seis estados fenológicos se inició a las 10 horas después de

  6. Measuring attentional bias in children with prominent ears: A prospective eye-tracking study.

    Science.gov (United States)

    Haworth, Rebecca; Sobey, Stephanie; Chorney, Jill M; Bezuhly, Michael; Hong, Paul

    2015-12-01

    When observing new faces, most people focus their attention on the central triangle of the face containing the eyes, nose and mouth. When viewing faces with prominent ears, observers may divert their attention from the central triangle. The objective of this study was to determine whether there was an objective attentional bias to prominent ears in comparison to non-prominent ears. A total of 24 naïve participants (13 female; mean age 22.88 years) viewed 15 photographs of children with bilateral prominent ears, unilateral prominent ears and non-prominent ears. Both pre- and post-otoplasty photographs of two patients were included. The eye movements of participants were recorded using the EyeLink 1000, a table-mounted eye-tracking device. Overall, the participants spent more time looking at the ear regions for faces with prominent ears in comparison to faces without prominent ears (p = 0.007, Z = -2.688). The attentional bias to the ear region of the patient who underwent bilateral otoplasty was significantly reduced in the post-operative photograph (p = 0.011, Z = -2.534). The patient who underwent unilateral otoplasty had no significant change in fixation times towards the ear region (p = 0.594, Z = -0.533). This study presents objective data to support the notion that observers show attentional bias to the ear region when viewing faces of children with prominent ears. The scope of this finding requires further research in both extent and impact. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. The X-Ray Polarization Signature of Quiescent Magnetars: Effect of Magnetospheric Scattering and Vacuum Polarization

    CERN Document Server

    Fernández, Rodrigo

    2011-01-01

    In the magnetar model, the quiescent non-thermal soft X-ray emission from Anomalous X-ray Pulsars and Soft-Gamma Repeaters is thought to arise from resonant comptonization of thermal photons by charges moving in a twisted magnetosphere. Robust inference of physical quantities from observations is difficult, because the process depends strongly on geometry and current understanding of the magnetosphere is not very deep. The polarization of soft X-ray photons is an independent source of information, and its magnetospheric imprint remains only partially explored. In this paper we calculate how resonant cyclotron scattering would modify the observed polarization signal relative to the surface emission, using a multidimensional Monte Carlo radiative transfer code that accounts for the gradual coupling of polarization eigenmodes as photons leave the magnetosphere. We employ a globally-twisted, self-similar, force-free magnetosphere with a power-law momentum distribution, assume a blackbody spectrum for the seed pho...

  8. Formation of Galactic Prominence in the Galactic Central Region

    Science.gov (United States)

    Peng, Chih-Han; Matsumoto, Ryoji

    2017-02-01

    We carried out 2.5-dimensional resistive MHD simulations to study the formation mechanism of molecular loops observed by Fukui et al. in the Galactic central region. Since it is hard to form molecular loops by lifting up dense molecular gas, we study the formation mechanism of molecular gas in rising magnetic arcades. This model is based on the in situ formation model of solar prominences, in which prominences are formed by cooling instability in helical magnetic flux ropes formed by imposing converging and shearing motion at footpoints of the magnetic arch anchored to the solar surface. We extended this model to Galactic center scale (a few hundreds of parsecs). Numerical results indicate that magnetic reconnection taking place in the current sheet that formed inside the rising magnetic arcade creates dense blobs confined by the rising helical magnetic flux ropes. Thermal instability taking place in the flux ropes forms dense molecular filaments floating at high Galactic latitude. The mass of the filament increases with time and can exceed {10}5 {M}ȯ .

  9. Simulating the in situ condensation process of solar prominences

    CERN Document Server

    Xia, Chun; Antolin, Patrick; Porth, Oliver

    2014-01-01

    Prominences in the solar corona are hundredfold cooler and denser than their surroundings, with a total mass of 1.e13 up to 1.e15 g. Here we report on the first comprehensive simulations of three-dimensional, thermally and gravitationally stratified magnetic flux ropes, where in situ condensation to a prominence happens due to radiative losses. After a gradual thermodynamic adjustment, we witness a phase where runaway cooling happens while counter-streaming shearing flows drain off mass along helical field lines. After this drainage, a prominence-like condensation resides in concave upward field regions, and this prominence retains its overall characteristics for more than two hours. While condensing, the prominence establishes a prominence-corona transition region, where magnetic field-aligned thermal conduction is operative during the runaway cooling. The prominence structure represents a force-balanced state in a helical flux rope. The simulated condensation demonstrates a right-bearing barb, as a remnant ...

  10. A Change in the Quiescent X-Ray Spectrum of the Neutron Star Low-mass X-Ray Binary MXB 1659-29

    NARCIS (Netherlands)

    E.M. Cackett; E.F. Brown; A. Cumming; N. Degenaar; J. Fridriksson; J. Homan; J.M. Miller; R. Wijnands

    2013-01-01

    The quasi-persistent neutron star low-mass X-ray binary MXB 1659-29 went into quiescence in 2001, and we have followed its quiescent X-ray evolution since. Observations over the first 4 yr showed a rapid drop in flux and temperature of the neutron star atmosphere, interpreted as cooling of the neutr

  11. Stellar Velocity Dispersion for a Strongly-Lensed, Intermediate-Mass Quiescent Galaxy at z=2.8

    CERN Document Server

    Hill, Allison R; Franx, Marijn; van de Sande, Jesse

    2016-01-01

    Measuring stellar velocity dispersions of quiescent galaxies beyond $z\\sim2$ is observationally challenging. Such measurements require near-infrared spectra with a continuum detection of at least moderate signal-to-noise, often necessitating long integrations. In this paper, we present deep X-Shooter spectroscopy of one of only two known gravitationally-lensed massive quiescent galaxies at $z>2$. This galaxy is quadruply imaged, with the brightest images magnified by a factor of $\\sim5$. The total exposure time of our data is 9.8 hours on-source; however the magnification, and the slit placement encompassing 2 images, provides a total equivalent exposure time of 215 hours. From this deep spectrum we measure a redshift ($z_{\\mathrm{spec}}=2.756\\pm0.001$), making this one of the highest redshift quiescent galaxies that is spectroscopically confirmed. We simultaneously fit both the spectroscopic and photometric data to determine stellar population parameters and conclude this galaxy is relatively young, intermed...

  12. SIMULATING THE IN SITU CONDENSATION PROCESS OF SOLAR PROMINENCES

    Energy Technology Data Exchange (ETDEWEB)

    Xia, C.; Keppens, R. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium); Antolin, P. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Porth, O. [Department of Applied Mathematics, The University of Leeds, Leeds LS2 9JT (United Kingdom)

    2014-09-10

    Prominences in the solar corona are a hundredfold cooler and denser than their surroundings, with a total mass of 10{sup 13} up to 10{sup 15} g. Here, we report on the first comprehensive simulations of three-dimensional, thermally and gravitationally stratified magnetic flux ropes where in situ condensation to a prominence occurs due to radiative losses. After a gradual thermodynamic adjustment, we witness a phase where runaway cooling occurs while counter-streaming shearing flows drain off mass along helical field lines. After this drainage, a prominence-like condensation resides in concave upward field regions, and this prominence retains its overall characteristics for more than two hours. While condensing, the prominence establishes a prominence-corona transition region where magnetic field-aligned thermal conduction is operative during the runaway cooling. The prominence structure represents a force-balanced state in a helical flux rope. The simulated condensation demonstrates a right-bearing barb, as a remnant of the drainage. Synthetic images at extreme ultraviolet wavelengths follow the onset of the condensation, and confirm the appearance of horns and a three-part structure for the stable prominence state, as often seen in erupting prominences. This naturally explains recent Solar Dynamics Observatory views with the Atmospheric Imaging Assembly on prominences in coronal cavities demonstrating horns.

  13. The executive prominent/memory prominent spectrum in Alzheimer's disease is highly heritable.

    Science.gov (United States)

    Mez, Jesse; Mukherjee, Shubhabrata; Thornton, Timothy; Fardo, David W; Trittschuh, Emily; Sutti, Sheila; Sherva, Richard; Kauwe, John S; Naj, Adam C; Beecham, Gary W; Gross, Alden; Saykin, Andrew J; Green, Robert C; Crane, Paul K

    2016-05-01

    Late-onset Alzheimer's disease (LOAD) can present heterogeneously, with several subtypes recognized, including dysexecutive AD. One way to identify people with dysexecutive AD is to consider the difference between memory and executive functioning, which we refer to as the executive prominent/memory prominent spectrum. We aimed to determine if this spectrum was heritable. We used neuropsychological and genetic data from people with mild LOAD (Clinical Dementia Rating 0.5 or 1.0) from the National Alzheimer's Coordinating Center and the Alzheimer's Disease Neuroimaging Initiative. We cocalibrated the neuropsychological data to obtain executive functioning and memory scores and used their difference as a continuous phenotype to calculate its heritability overall and by chromosome. Narrow-sense heritability of the difference between memory and executive functioning scores was 0.68 (standard error 0.12). Single nucleotide polymorphisms on chromosomes 1, 2, 4, 11, 12, and 18 explained the largest fraction of phenotypic variance, with signals from each chromosome accounting for 5%-7%. The chromosomal pattern of heritability differed substantially from that of LOAD itself.

  14. Stability of nanofluids in quiescent and shear flow fields

    Directory of Open Access Journals (Sweden)

    Chen Haisheng

    2011-01-01

    Full Text Available Abstract An experimental study was conducted to investigate the structural stability of ethylene glycol-based titanium dioxide nanoparticle suspensions (nanofluids prepared by two-step method. The effects of particle concentration, fluid temperature, shear rate and shear duration were examined. Particle size and thermal conductivity measurements in quiescent state indicated the existence of aggregates and that they were stable in temperatures up to 60°C. Shear stability tests suggested that the structure of nanoparticle aggregates was stable in a shear interval of 500-3000 s-1 measured over a temperature range of 20-60°C. These findings show directions to resolve controversies surrounding the underlying mechanisms of thermal conduction and convective heat transfer of nanofluids.

  15. Volatilization of hydrogen sulfide from a quiescent surface.

    Science.gov (United States)

    de Cassia Feroni, Rita; Santos, Jane Meri; Reis, Neyval Costa

    2012-01-01

    Air-water mass transfer of hydrogen sulfide from a shallow tank with a quiescent surface under the influence of weak wind stress on the water surface was studied numerically using a two-dimensional model. The flow field in the tank was investigated using a computational code based on a finite volume, which is used to numerically solve momentum, mass and continuity conservation equations. The results show that water phase flow field is strongly dependent on the wind-induced surface velocity and the aspect ratio of the tank. Based on the numerical study, the liquid-side mass transfer coefficient is correlated with Reynolds number (R(e)), tank aspect ratio (AR) and Schmidt number (S(c)). Overall mass transfer coefficient (K(L)) values extend further downstream as the R(e) number increases.

  16. Amiloride, protein synthesis, and activation of quiescent cells.

    Science.gov (United States)

    Lubin, M; Cahn, F; Coutermarsh, B A

    1982-11-01

    Amiloride is known to inhibit both influx of sodium ions and activation of quiescent cells by growth factors. The coincidence of these effects has been cited to support the proposal that influx of sodium ions acts as a mitogenic signal. Although it was noted that amiloride inhibited protein synthesis, this was attributed to an action on transport of amino acids, particularly those coupled to sodium fluxes. We find, however, that amiloride directly inhibits polypeptide synthesis in a reticulocyte lysate. In Swiss 3T3 cells, concentrations of amiloride and of cycloheximide that are nearly matched in their degree of inhibition of protein synthesis, produce about the same degree of inhibition of transit of cells from G0 to S. Inhibition of protein synthesis is sufficient to explain the effect of amiloride on mitogenesis; the drug, therefore, is not suitable for testing the hypothesis that sodium influx is a mitogenic signal.

  17. Thermal stability analysis of the fine structure of solar prominences

    Science.gov (United States)

    Demoulin, Pascal; Malherbe, Jean-Marie; Schmieder, Brigitte; Raadu, Mickael A.

    1986-01-01

    The linear thermal stability of a 2D periodic structure (alternatively hot and cold) in a uniform magnetic field is analyzed. The energy equation includes wave heating (assumed proportional to density), radiative cooling and both conduction parallel and orthogonal to magnetic lines. The equilibrium is perturbed at constant gas pressure. With parallel conduction only, it is found to be unstable when the length scale 1// is greater than 45 Mn. In that case, orthogonal conduction becomes important and stabilizes the structure when the length scale is smaller than 5 km. On the other hand, when the length scale is greater than 5 km, the thermal equilibrium is unstable, and the corresponding time scale is about 10,000 s: this result may be compared to observations showing that the lifetime of the fine structure of solar prominences is about one hour; consequently, our computations suggest that the size of the unresolved threads could be of the order of 10 km only.

  18. Source of a Prominent Poleward Surge During Solar Cycle 24

    CERN Document Server

    Yeates, A R; van Driel-Gesztelyi, L

    2015-01-01

    As an observational case study, we consider the origin of a prominent poleward surge of leading polarity, visible in the magnetic butterfly diagram during Solar Cycle 24. A new technique is developed for assimilating individual regions of strong magnetic flux into a surface flux transport model. By isolating the contribution of each of these regions, the model shows the surge to originate primarily in a single high-latitude activity group consisting of a bipolar active region present in Carrington Rotations 2104-05 (November 2010-January 2011) and a multipolar active region in Rotations 2107-08 (February-April 2011). This group had a strong axial dipole moment opposed to Joy's law. On the other hand, the modelling suggests that the transient influence of this group on the butterfly diagram will not be matched by a large long-term contribution to the polar field, because of its location at high latitude. This is in accordance with previous flux transport models.

  19. Giant coronal loops dominate the quiescent X-ray emission in rapidly rotating M stars

    CERN Document Server

    Cohen, O; Garraffo, C; Saar, S H; Wolk, S J; Kashyap, V L; Drake, J J; Pillitteri, I

    2016-01-01

    Observations indicate that magnetic fields in rapidly rotating stars are very strong, on both small and large scales. What is the nature of the resulting corona? Here we seek to shed some light on this question. We use the results of an anelastic dynamo simulation of a rapidly rotating fully-convective M-star to drive a physics-based model for the stellar corona. We find that due to the several kilo Gauss large-scale magnetic fields at high latitudes, the corona and its X-ray emission are dominated by star-size large hot loops, while the smaller, underlying colder loops are not visible much in the X-ray. Based on this result we propose that, in rapidly rotating stars, emission from such coronal structures dominates the quiescent, cooler but saturated X-ray emission.

  20. Quiescent Superhumps Detected in the Dwarf Nova V344 Lyrae by Kepler

    CERN Document Server

    Still, Martin; Wood, Matt A; Cannizzo, John K; Smale, Alan P

    2010-01-01

    The timing capabilities and sensitivity of Kepler, NASA's observatory to find Earth-sized planets within the habitable zone of stars, are well matched to the timescales and amplitudes of accretion disk variability in cataclysmic variables. This instrumental combination provides an unprecedented opportunity to test and refine stellar accretion paradigms with high-precision, uniform data, containing none of the diurnal or season gaps that limit ground-based observations. We present a 3-month, 1 minute cadence Kepler light curve of V344 Lyr, a faint, little-studied dwarf nova within the Kepler field. The light curve samples V344 Lyr during five full normal outbursts and one superoutburst. Surprisingly, the superhumps found during superoutburst continue to be detected during the following quiescent state and normal outburst. The fractional excess of superhump period over the presumed orbital period suggests a relatively high binary mass ratio in a system where the radius of the accretion disk must vary by less th...

  1. Discriminating among stellar population synthesis models of the TP-AGB phase in early quiescent galaxies

    Science.gov (United States)

    MacDougall, Mason; Newman, Andrew; Belli, Sirio; Ellis, Richard S.

    2017-01-01

    Galactic evolution at high redshifts is largely understood through stellar population synthesis (SPS) modeling of spectra and photometry integrated over all starlight of a galaxy. However, complex and poorly understood stellar phases like the unstable thermally-pulsating asymptotic giant branch (TP-AGB) phase make SPS modeling a difficult task. Recent models fail to agree on the TP-AGB contribution to the infrared luminosity, leading to significant discrepancy among the properties derived from modern SPS models when applied to early galaxies. Here we provide a thorough assessment of each of the most widely used SPS models by comparing their results and assessing their accuracy in modeling our unique dataset. We combine high-resolution spectroscopic observations from Keck/MOSFIRE with photometric data for 21 early quiescent galaxies with redshifts of z ~ 2. These galaxies are around the age of peak TP-AGB activity, between ~0.3 and 2 Gyr, and therefore provide an ideal test of the models. We find that models with a “light” TP-AGB contribution provide much better descriptions of our galaxies at ages of ~1 Gyr or less. This is true at high statistical significance and holds for models with or without dust reddening. However, contrary to previous studies, the model-dependent photometrically estimated ages are similar among the models, but they show only moderate agreement with the more model-independent spectroscopic ages derived from stellar absorption lines. The largest discrepancies are found for the Charlot & Bruzual (2007) models which show an artificial clustering of ages around 1 Gyr. The TP-AGB “light” models require more reddening, which can be independently tested by examining dust emission in the mid-infrared. The modeled fluxes are also mostly consistent with mid-infrared observations, with the exception of one model. Resolving these differences among the models will substantially strengthen our estimates of the properties of early quiescent

  2. Isolation of quiescent and nonquiescent cells from yeast stationary-phase cultures

    NARCIS (Netherlands)

    Allen, Chris; Büttner, Sabrina; Aragon, Anthony D.; Thomas, Jason A.; Meirelles, Osorio; Jaetao, Jason E.; Benn, Don; Ruby, Stephanie W.; Veenhuis, Marten; Madeo, Frank; Werner-Washburne, Margaret

    2006-01-01

    Quiescence is the most common and, arguably, most poorly understood cell cycle state. This is in part because pure populations of quiescent cells are typically difficult to isolate. We report the isolation and characterization of quiescent and nonquiescent cells from stationary-phase (SP) yeast

  3. Quiescent X-ray emission from Cen X-4: a variable thermal component

    NARCIS (Netherlands)

    E.M. Cackett; E.F. Brown; J.M. Miller; R. Wijnands

    2010-01-01

    The nearby neutron star low-mass X-ray binary, Cen X-4, has been in a quiescent state since its last outburst in 1979. Typically, quiescent emission from these objects consists of thermal emission (presumably from the neutron star surface) with an additional hard power-law tail of unknown nature. Va

  4. Silent Waters Run Deep. Quiescent stem cells in homeostasis and cancer

    NARCIS (Netherlands)

    S.G. Roth (Sabrina)

    2012-01-01

    markdownabstract__Abstract__ The Introduction summarizes the current literature on quiescence in adult stem cell niches and the various methods for the isolation of quiescent stem cells, outlines the complexity of the intestinal stem cell niche, and formulates the hypothesis that quiescent

  5. Magnetic Flux Cancellation and Formation of Prominence

    Science.gov (United States)

    Miley, George; Kim, Mun Song; Chon Nam, Sok; Kim, Kyong Chol

    2015-08-01

    Magnetic flux cancellation appears to be closely related to various kinds of solar activities such as flares, microflares/surges/jets, X-ray bright points, erupting mini-filaments, transition region explosive events, filament formation, filament activation and eruption, and coronal mass ejections. It is commonly believed that magnetic reconnections in the low atmosphere are responsible for canceling magnetic features, and magnetic fragments are observed to originate as bipoles. According to the Sweet-Parker type reconnection model, the inflow speed closely corresponds to the converging speed of each pole in a canceling magnetic feature and the rate of flux cancellation must be explained by the observed converging speed. As distinct from the corona, the efficiency of photospheric magnetic reconnection may be due to the small Cowling conductivity, instead of the Spitzer, of weakly ionized and magnetized plasma in the low atmosphere of the sun. Using the VAL-C atmospheric model and Cowling conductivity, we have computed the parameters describing Sweet-Parker type reconnecting current sheets in the plasma of the solar photosphere and chromosphere, and particularly for the phenomena of magnetic flux cancellation and dark filament formation which occurred on July 2, 1994 we have estimated the rate of flux cancellation, the inflow speed(the converging speed) and the upward mass flux to compare with the observation. The results show that when taking account of the Cowling conductivity in the low atmosphere, large flux cancellation rates(>1019Mxhr-1) in solar active regions are better explained than by the Spitzer conductivity-considered reconnection model. Particularly for the flux cancellation event on July 2, 1994, the inflow speed(0.26kms-1)is almost similar to the converging speed(0.22kms-1)and the upward mass flux(3.3X1012gs-1) in the model is sufficient for the large dark filament formation in a time of several hours through magnetic flux cancellation process.

  6. On the Visibility of Prominence Fine Structures at Radio Millimeter Wavelengths

    Science.gov (United States)

    Heinzel, P.; Berlicki, A.; Bárta, M.; Karlický, M.; Rudawy, P.

    2015-07-01

    Prominence temperatures have so far mainly been determined by analyzing spectral line shapes, which is difficult when the spectral lines are optically thick. The radio spectra in the millimeter range offer a unique possibility to measure the kinetic temperature. However, studies in the past used data with insufficient spatial resolution to resolve the prominence fine structures. The aim of this article is to predict the visibility of prominence fine structures in the submillimeter/millimeter (SMM) domain, to estimate their brightness temperatures at various wavelengths, and to demonstrate the feasibility and usefulness of future high-resolution radio observations of solar prominences with ALMA ( Atacama Large Millimeter-submillimeter Array). Our novel approach is the conversion of H coronagraphic images into microwave spectral images. We show that the spatial variations of the prominence brightness both in the H line and in the SMM domain predominantly depend on the line-of-sight emission measure of the cool plasma, which we derive from the integrated intensities of the observed H line. This relation also offers a new possibility to determine the SMM optical thickness from simultaneous H observations with high resolution. We also describe how we determine the prominence kinetic temperature from SMM spectral images. Finally, we apply the ALMA image-processing software Common Astronomy Software Applications (CASA) to our simulated images to assess what ALMA would detect at a resolution level that is similar to the coronagraphic H images used in this study. Our results can thus help in preparations of first ALMA prominence observations in the frame of science and technical verification tests.

  7. Giant tornadoes as rotating legs of solar prominences

    CERN Document Server

    Wedemeyer, Sven; van der Voort, Luc Rouppe; Bosnjak, Antonija; Antolin, Patrick

    2013-01-01

    Observations in the 171 AA channel of the Atmospheric Imaging Assembly of the space-borne Solar Dynamics Observatory show tornadoes-like features in the atmosphere of the Sun. These giant tornadoes appear as dark, elongated and apparently rotating structures in front of a brighter background. This phenomenon is thought to be produced by rotating magnetic field structures that extend throughout the atmosphere. We characterize giant tornadoes through a statistical analysis of properties like spatial distribution, lifetimes, and sizes. A total number of 201 giant tornadoes are detected in a period of 25 days, suggesting that on average about 30 events are present across the whole Sun at a time close to solar maximum. Most tornadoes appear in groups and seem to form the legs of prominences, thus serving as plasma sources/sinks. Additional Halpha observations with the Swedish 1-m Solar Telescope imply that giant tornadoes rotate as a structure although clearly exhibiting a thread-like structure. We observe tornado...

  8. Preferential gene expression in quiescent human lung fibroblasts.

    Science.gov (United States)

    Coppock, D L; Kopman, C; Scandalis, S; Gilleran, S

    1993-06-01

    The exit from the proliferative cell cycle into a reversible quiescence (G0) is an active process that is not yet well understood at the molecular level. Investigation of G0-specific gene expression is an important step in studying the mechanism regulating the entrance to quiescence. Using the human embryo lung fibroblast (WI38) as a model system, we have isolated complementary DNA clones that are expressed at a higher level in quiescent cells than in logarithmically growing cells. We have identified complementary DNAs from eight genes including collagen alpha 1(VI), collagen alpha 1(III), decorin, complement C1r, collagen alpha 1(I), collagen alpha 2(I), and two novel genes, Q6 and Q10. We have named this class of quiescence-inducible genes quiescins. Expression of these genes was induced just as proliferation slowed, as indicated by the level of histone H2B mRNA, [3H]-thymidine incorporation, and cell number. The level of expression of the novel genes, Q6 and Q10, increased at the same time as the other genes. Q6 has two mRNAs of 3 and 4 kb, whereas Q10 mRNA is about 1.0 kb. The expression of the quiescins was not induced by blocking the cell cycle in S phase with aphidicolin or in G1 with lovastatin. However, the genes were highly induced by trypsinization or scraping of the cells during logarithmic growth. This induction was not blocked by inhibitors of RNA synthesis. The expression of decorin and Q6 was very low in SV40-transformed cells (VA13) either in logarithmic growth or at high density, whereas the gene Q10 was expressed more highly in VA13 than in WI38 cells. The finding that expression of some components of the extracellular matrix is induced as cells enter G0 suggests that they may have a role in both the induction and the maintenance of the quiescent state. The quiescins will serve as molecular markers for the investigation of mechanisms that regulate the onset of quiescence.

  9. Measles virus glycoprotein-pseudotyped lentiviral vector-mediated gene transfer into quiescent lymphocytes requires binding to both SLAM and CD46 entry receptors.

    Science.gov (United States)

    Frecha, Cecilia; Lévy, Camille; Costa, Caroline; Nègre, Didier; Amirache, Fouzia; Buckland, Robin; Russell, Steven J; Cosset, François-Loïc; Verhoeyen, Els

    2011-06-01

    Gene transfer into quiescent T and B cells is of importance for gene therapy and immunotherapy approaches to correct hematopoietic disorders. Previously, we generated lentiviral vectors (LVs) pseudotyped with the Edmonston measles virus (MV) hemagglutinin and fusion glycoproteins (Hgps and Fgps) (H/F-LVs), which, for the first time, allowed efficient transduction of quiescent human B and T cells. These target cells express both MV entry receptors used by the vaccinal Edmonston strain, CD46 and signaling lymphocyte activation molecule (SLAM). Interestingly, LVs pseudotyped with an MV Hgp, blind for the CD46 binding site, were completely inefficient for resting-lymphocyte transduction. Similarly, SLAM-blind H mutants that recognize only CD46 as the entry receptor did not allow stable LV transduction of resting T cells. The CD46-tropic LVs accomplished vector-cell binding, fusion, entry, and reverse transcription at levels similar to those achieved by the H/F-LVs, but efficient proviral integration did not occur. Our results indicate that both CD46 and SLAM binding sites need to be present in cis in the Hgp to allow successful stable transduction of quiescent lymphocytes. Moreover, the entry mechanism utilized appears to be crucial: efficient transduction was observed only when CD46 and SLAM were correctly engaged and an entry mechanism that strongly resembles macropinocytosis was triggered. Taken together, our results suggest that although vector entry can occur through the CD46 receptor, SLAM binding and subsequent signaling are also required for efficient LV transduction of quiescent lymphocytes to occur.

  10. Automatically Detecting and Tracking Coronal Mass Ejections. I. Separation of Dynamic and Quiescent Components in Coronagraph Images

    Science.gov (United States)

    Morgan, Huw; Byrne, Jason P.; Habbal, Shadia Rifai

    2012-06-01

    Automated techniques for detecting and tracking coronal mass ejections (CMEs) in coronagraph data are of ever increasing importance for space weather monitoring and forecasting. They serve to remove the biases and tedium of human interpretation, and provide the robust analysis necessary for statistical studies across large numbers of observations. An important requirement in their operation is that they satisfactorily distinguish the CME structure from the background quiescent coronal structure (streamers, coronal holes). Many studies resort to some form of time differencing to achieve this, despite the errors inherent in such an approach—notably spatiotemporal crosstalk. This article describes a new deconvolution technique that separates coronagraph images into quiescent and dynamic components. A set of synthetic observations made from a sophisticated model corona and CME demonstrates the validity and effectiveness of the technique in isolating the CME signal. Applied to observations by the LASCO C2 and C3 coronagraphs, the structure of a faint CME is revealed in detail despite the presence of background streamers that are several times brighter than the CME. The technique is also demonstrated to work on SECCHI/COR2 data, and new possibilities for estimating the three-dimensional structure of CMEs using the multiple viewing angles are discussed. Although quiescent coronal structures and CMEs are intrinsically linked, and although their interaction is an unavoidable source of error in any separation process, we show in a companion paper that the deconvolution approach outlined here is a robust and accurate method for rigorous CME analysis. Such an approach is a prerequisite to the higher-level detection and classification of CME structure and kinematics.

  11. Quiescent and proliferative fibroblasts exhibit differential p300 HAT activation through control of 5-methoxytryptophan production.

    Directory of Open Access Journals (Sweden)

    Huei-Hsuan Cheng

    Full Text Available Quiescent fibroblasts possess unique genetic program and exhibit high metabolic activity distinct from proliferative fibroblasts. In response to inflammatory stimulation, quiescent fibroblasts are more active in expressing cyclooxygenase-2 and other proinflammatory genes than proliferative fibroblasts. The underlying transcriptional mechanism is unclear. Here we show that phorbol 12-myristate 13-acetate (PMA and cytokines increased p300 histone acetyltransferase activity to a higher magnitude (> 2 fold in quiescent fibroblasts than in proliferative fibroblasts. Binding of p300 to cyclooxygenase-2 promoter was reduced in proliferative fibroblasts. By ultrahigh-performance liquid chromatography coupled with a quadrupole time of flight mass spectrometer and enzyme-immunoassay, we found that production of 5-methoxytryptophan was 2-3 folds higher in proliferative fibroblasts than that in quiescent fibroblasts. Addition of 5-methoxytryptophan and its metabolic precursor, 5-hydroxytryptophan, to quiescent fibroblasts suppressed PMA-induced p300 histone acetyltransferase activity and cyclooxygenase-2 expression to the level of proliferative fibroblasts. Silencing of tryptophan hydroxylase-1 or hydroxyindole O-methyltransferase in proliferative fibroblasts with siRNA resulted in elevation of PMA-induced p300 histone acetyltransferase activity to the level of that in quiescent fibroblasts, which was rescued by addition of 5-hydroxytryptophan or 5-methoxytryptophan. Our findings indicate that robust inflammatory gene expression in quiescent fibroblasts vs. proliferative fibroblasts is attributed to uncontrolled p300 histone acetyltransferase activation due to deficiency of 5-methoxytryptophan production. 5-methoxytryptophan thus is a potential valuable lead compound for new anti-inflammatory drug development.

  12. PROMINENCE PLASMA DIAGNOSTICS THROUGH EXTREME-ULTRAVIOLET ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Landi, E. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Reale, F. [Dipartimento di Fisica e Chimica, Universita di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy)

    2013-07-20

    In this paper, we introduce a new diagnostic technique that uses EUV and UV absorption to determine the electron temperature and column emission measure, as well as the He/H relative abundance of the absorbing plasma. If a realistic assumption on the geometry of the latter can be made and a spectral code such as CHIANTI is used, then this technique can also yield the absorbing plasma hydrogen and electron density. This technique capitalizes on the absorption properties of hydrogen and helium at different wavelength ranges and temperature regimes. Several cases where this technique can be successfully applied are described. This technique works best when the absorbing plasma is hotter than 15,000 K. We demonstrate this technique on AIA observations of plasma absorption during a coronal mass ejection eruption. This technique can be easily applied to existing observations of prominences and cold plasmas in the Sun from almost all space missions devoted to the study of the solar atmosphere, which we list.

  13. An autonomous sperm-like propulsor in a quiescent flow

    Science.gov (United States)

    Kim, Boyoung; Park, Sung Goon; Sung, Hyung Jin

    2016-11-01

    Flapping motions of flexible fins are widespread in nature. Birds, fish, and insects use their wings, fins, or bodies to stay afloat and to advance forward in the surrounding fluids. It is important to understand the physics of the flapping motions to utilize them for the biomimetic machines. In the present study, we introduce a sperm-like propulsor that consists of a rigid head containing genetic information and a flapping flexible tail for propulsion. The head gives a sinusoidal torque to the leading edge of the tail, and the flexible tail flaps along the leading edge. In other words, the sperm-like propulsor is moved by an oscillating relative angle between the head and the leading edge of the tail. Unlike self-propelled heaving and pitching fins, the 'autonomous' sperm-like propulsor has no prescribed motion or constraint referenced from outside coordinates. The penalty method and the immersed boundary method are used to solve the autonomous sperm-like propulsor in a quiescent flow. The cruising speed and the propulsive efficiency of the propulsor are explored as a function of the head size (D/ L) , the pitching angle (θ0) , the pitching frequency (f) , and the distance from the wall (G/ L) .

  14. CANDELS: The progenitors of compact quiescent galaxies at z~2

    CERN Document Server

    Barro, Guillermo; Perez-Gonzalez, Pablo G; Koo, David C; Williams, Christina C; Kocevski, Dale D; Trump, Jonathan R; Mozena, Mark; McGrath, Elizabeth; van der Wel, Arjen; Wuyts, Stijn; Bell, Eric F; Croton, Darren J; Dekel, Avishai; Ashby, M L N; Ferguson, Henry C; Fontana, Adriano; Giavalisco, Mauro; Grogin, Norman A; Guo, Yicheng; Hathi, Nimish P; Hopkins, Philip F; Huang, Kuang-Han; Koekemoer, Anton M; Kartaltepe, Jeyhan S; Lee, Kyoung-Soo; Newman, Jeffrey A; Porter, Lauren A; Primack, Joel R; Ryan, Russell E; Rosario, David; Somerville, Rachel S

    2012-01-01

    We combine high-resolution HST/WFC3 images with multi-wavelength photometry to track the evolution of structure and activity of massive (log(M*) > 10) galaxies at redshifts z = 1.4 - 3 in two fields of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). We detect compact, star-forming galaxies (cSFGs) whose number densities, masses, sizes, and star formation rates qualify them as likely progenitors of compact, quiescent, massive galaxies (cQGs) at z = 1.5 - 3. At z > 2 most cSFGs have specific star-formation rates (sSFR = 10^-9 yr^-1) half that of typical, massive SFGs at the same epoch, and host X-ray luminous AGN 30 times (~30%) more frequently. These properties suggest that cSFGs are formed by gas-rich processes (mergers or disk-instabilities) that induce a compact starburst and feed an AGN, which, in turn, quench the star formation on dynamical timescales (few 10^8 yr). The cSFGs are continuously being formed at z = 2 - 3 and fade to cQGs by z = 1.5. After this epoch, cSFGs are r...

  15. UV Extinction Towards a Quiescent Molecular Cloud in the SMC

    CERN Document Server

    Apellániz, J Maíz

    2012-01-01

    Context: The mean UV extinction law for the Small Magellanic Cloud (SMC) is usually taken as a template for low-metallicity galaxies. However, its current derivation is based on only five stars, thus placing doubts on its universality. An increase in the number of targets with measured extinction laws in the SMC is necessary to determine its possible dependence on parameters such as metallicity and star-forming activity. Aims: To measure the UV extinction law for several stars in the quiescent molecular cloud SMC B1-1. Methods: We obtained HST/STIS slitless UV spectroscopy of a 25"x25" field of view and we combined it with ground-based NIR and visible photometry of the stars in the field. The results were processed using the Bayesian photometric package CHORIZOS to derive the visible-NIR extinction values for each star. The unextinguished Spectral Energy Distributions (SEDs) obtained in this way were then used to derive the UV extinction law for the four most extinguished stars. We also recalculated the visib...

  16. Transient activity in the loop prominence system of a flare active region

    Science.gov (United States)

    Bagare, S. P.; Nagabhushana, B. S.; Aleem, P. S. M.

    1989-09-01

    Solar limb observations of the activity in a loop prominence system associated with an active region were obtained on February 2, 1984. The activity was observed for a total duration of over seven hours of which the maximum phase lasted for about an hour. From a series of Ca II K prominence spectroheliograms taken during this phase, the individual loops appear to experience a sequence of activity; the brightening of kernel, brightening of portions of the loop, motion of the enhanced brightenings along the legs of the loop and a diffuse appearance of the loop at the end phase. The details of these phenomena and other associated activity are described.

  17. The Variable Quiescent X-Ray Emission of the Neutron Star Transient XTE J1701-462

    CERN Document Server

    Fridriksson, Joel K; Wijnands, Rudy; Cackett, Edward M; Altamirano, Diego; Brown, Edward F; Degenaar, Nathalie; Mendez, Mariano; Belloni, Tomaso M

    2011-01-01

    We present the results of continued monitoring of the quiescent neutron star low-mass X-ray binary XTE J1701-462 with Chandra and Swift. A new Chandra observation from 2010 October extends our tracking of the neutron star surface temperature from ~800 days to ~1160 days since the end of an exceptionally luminous 19 month outburst. This observation indicates that the neutron star crust may still be slowly cooling toward thermal equilibrium with the core; another observation further into quiescence is needed to verify this. The shape of the cooling curve is consistent with that of a broken power law, although an exponential decay to a constant level cannot be excluded with the present data. To investigate possible low-level activity we conducted a monitoring campaign of XTE J1701-462 with Swift during 2010 April-October. Short-term flares - presumably arising from episodic low-level accretion - were observed up to a luminosity of ~1e35 erg/s, ~20 times higher than the normal quiescent level. We conclude that fl...

  18. Low Gas Fractions Connect Compact Star-Forming Galaxies to their z ~ 2 Quiescent Descendants

    CERN Document Server

    Spilker, Justin S; Marrone, Daniel P; Weiner, Benjamin J; Whitaker, Katherine E; Williams, Christina C

    2016-01-01

    Early quiescent galaxies at z~2 are known to be remarkably compact compared to their nearby counterparts. Possible progenitors of these systems include galaxies that are structurally similar, but are still rapidly forming stars. Here, we present Karl G. Jansky Very Large Array (VLA) observations of the CO(1-0) line towards three such compact, star-forming galaxies at z~2.3, significantly detecting one. The VLA observations indicate baryonic gas fractions >~5 times lower and gas depletion times >~10 times shorter than normal, extended massive star-forming galaxies at these redshifts. At their current star formation rates, all three objects will deplete their gas reservoirs within 100Myr. These objects are among the most gas-poor objects observed at z>2, and are outliers from standard gas scaling relations, a result which remains true regardless of assumptions about the CO-H2 conversion factor. Our observations are consistent with the idea that compact, star-forming galaxies are in a rapid state of transition t...

  19. The first X-ray imaging spectroscopy of quiescent solar active regions with NuSTAR

    CERN Document Server

    Hannah, I G; Smith, D M; Glesener, L; Krucker, S; Hudson, H S; Madsen, K K; Marsh, A; White, S M; Caspi, A; Shih, A Y; Harrison, F A; Stern, D; Boggs, S E; Christensen, F E; Craig, W W; Hailey, C J; Zhang, W W

    2016-01-01

    We present the first observations of quiescent active regions (ARs) using NuSTAR, a focusing hard X-ray telescope capable of studying faint solar emission from high temperature and non-thermal sources. We analyze the first directly imaged and spectrally resolved X-rays above 2~keV from non-flaring ARs, observed near the west limb on 2014 November 1. The NuSTAR X-ray images match bright features seen in extreme ultraviolet and soft X-rays. The NuSTAR imaging spectroscopy is consistent with isothermal emission of temperatures $3.1-4.4$~MK and emission measures $1-8\\times 10^{46}$~cm$^{-3}$. We do not observe emission above 5~MK but our short effective exposure times restrict the spectral dynamic range. With few counts above 6~keV, we can place constraints on the presence of an additional hotter component between 5 and 12~MK of $\\sim 10^{46}$cm$^{-3}$ and $\\sim 10^{43}$ cm$^{-3}$, respectively, at least an order of magnitude stricter than previous limits. With longer duration observations and a weakening solar c...

  20. Winter speed-up of ice flow at quiescent surge-type glaciers in Yukon, Canada

    Science.gov (United States)

    Furuya, M.; Abe, T.

    2013-12-01

    Glacier surge exhibits order-of-magnitude faster velocity and km-scale terminus advance during its short active phase after a long quiescent period. The observations of glacier surge are still limited, and the mechanisms of glacier surge cycle remain elusive. Moreover, with the exception of several well-examined glaciers, the glacier dynamics during their quiescent periods remains even more uncertain due to the paucity of surface velocity measurement data. Here we examined spatial-temporal changes in the ice surface velocity of surge-type glaciers in the St. Elias Mountains near the border of Alaska and Yukon during the period from December 2006 to March 2011. We applied the offset-tracking (feature-tracking) technique to the L-band synthetic aperture radar (SAR) images derived from the Japanese Advanced Land Observation Satellite (ALOS). The Chitina, Anderson, Walsh, and Logan Glaciers, the major subpolar surge-type glaciers of the Chitina River valley system, could be examined with the highest temporal resolution because of the overlap of multiple satellite tracks. We have found significant upstream accelerations from fall to winter at a number of glaciers during their quiescence. Moreover, whereas the upstream propagating summer speed-up was observed, the winter speed-up propagated from upstream to downglacier. Although the winter speed-up seems to be at odds with the well-known summer speed-up, these observations are consistent with the fragmentary but well-known fact of glacier surge that often initiates in winter, suggesting that some of the mechanisms would be valid even during quiescent phases. Ice surface velocity at mountain glaciers and ice sheets typically exhibits the greatest acceleration from spring to early summer, followed by deceleration in mid-summer to fall, and is slowest in winter. These short-term velocity changes are attributed to subglacial slip associated with water pressure changes that occur because of the seasonal variability of

  1. Dynamics of a prominence-horn structure during its evaporation in the solar corona

    CERN Document Server

    Wang, Bing; Fu, Jie; Li, Bo; Li, Xing; Liu, Wei

    2016-01-01

    The physical connection among and formation mechanisms of various components of the prominence-horn cavity system remain elusive. Here we present observations of such a system, focusing on a section of the prominence that rises and separates gradually from the main body. This forms a configuration sufficiently simple to yield clues to the above issues. It is characterized by embedding horns, oscillations, and a gradual disappearance of the separated material. The prominence-horn structure exhibits a large amplitude longitudinal oscillation with a period of ~150 minutes and an amplitude of ~30 Mm along the trajectory defined by the concave horn structure. The horns also experience a simultaneous transverse oscillation with a much smaller amplitude (~3 Mm) and shorter period (~10-15 minutes), likely representative of a global mode of the large-scale magnetic structure. The gradual disappearance of the structure indicates that the horn, an observational manifestation of the field-aligned transition region separa...

  2. Unusual migration of the prominence activities in the southern hemisphere during Cycle 23--24

    CERN Document Server

    Shimojo, Masumi

    2013-01-01

    The solar activity in Cycle 23--24 shows differences from the previous cycles that were observed with modern instruments, e.g. long cycle duration and a small number of sunspots. To appreciate the anomalies further, we investigated the prominence eruptions and disappearances observed with the Nobeyama Radioheliograph during over 20 years. Consequently, we found that the occurrence of the prominence activities in the northern hemisphere is normal because the period of the number variation is 11 years and the migration of the producing region of the prominence activities traces the migration of 11 years ago. On the other hand, the migration in the southern hemisphere significantly differs from that in the northern hemisphere and the previous cycles. The prominence activities occurred over -50 degrees latitude in spite of the late decay phase of Cycle 23, and the number of the prominence activities in the higher latitude region (over -65 degrees) is very small even near the solar maximum of Cycle 24. The results...

  3. ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

    Energy Technology Data Exchange (ETDEWEB)

    Luna, M.; Moreno-Insertis, F. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Priest, E. [Mathematics Institute, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2015-07-20

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

  4. A global downregulation of microRNAs occurs in human quiescent satellite cells during myogenesis

    NARCIS (Netherlands)

    Koning, Merel; Werker, Paul M N; van Luyn, Marja J A; Krenning, Guido; Harmsen, Martin C

    2012-01-01

    During myogenesis, human satellite cells differentiate and form multinucleated myotubes, while a fraction of the human satellite cells enter quiescence. These quiescent satellite cells are able to activate, proliferate and contribute to muscle regeneration. Post-transcriptional regulation of

  5. Cross-linguistic evidence for gender as a prominence feature.

    Science.gov (United States)

    Esaulova, Yulia; von Stockhausen, Lisa

    2015-01-01

    This paper discusses recent findings in the online sentence processing research that suggest to consider gender information a prominence feature. Prominence features are hierarchically ordered information types that interact with formal features of arguments (e.g., grammatical functions, thematic roles) and thus determine the readers' ability to efficiently interpret linguistic ambiguities. While previous research addressed a number of prominence features (e.g., animacy, definiteness, person), there is now first empirical evidence indicating that gender information also influences the assignment of thematic roles across languages. Grammatically masculine role nouns are processed faster as agents than patients compared to feminine ones. Stereotypically male role nouns (e.g., electrician) are integrated with an agent role easier than neutral ones (e.g., musician), which in turn are integrated easier than female ones (e.g., beautician). Conceptualizing gender as a prominence feature will not only expand our knowledge about information types relevant for online comprehension but also uncover subtle gender biases present in language. The present work explores the possibility for a theoretical integration of social psychological and psycholinguistic research focusing on gender with research on prominence. Potential advantages an interdisciplinary approach to the study of gender as a prominence feature, open questions and future directions are discussed.

  6. Cross-linguistic Evidence for Gender as a Prominence Feature

    Directory of Open Access Journals (Sweden)

    Yulia eEsaulova

    2015-09-01

    Full Text Available This paper discusses recent findings in the online sentence processing research that suggest to consider gender information a prominence feature. Prominence features are hierarchically ordered information types that interact with formal features of arguments (e.g., grammatical functions, thematic roles and thus determine the readers’ ability to efficiently interpret linguistic ambiguities. While previous research addressed a number of prominence features (e.g., animacy, definiteness, person, there is now first empirical evidence indicating that gender information also influences the assignment of thematic roles across languages. Grammatically masculine role nouns are processed faster as agents than patients compared to feminine ones. Stereotypically male role nouns (e.g., electrician are integrated with an agent role easier than neutral ones (e.g., musician, which in turn are integrated easier than female ones (e.g., beautician. Conceptualizing gender as a prominence feature will not only expand our knowledge about information types relevant for online comprehension but also uncover subtle gender biases present in language. The present work explores the possibility for a theoretical integration of social psychological and psycholinguistic research focusing on gender with research on prominence. Potential advantages an interdisciplinary approach to the study of gender as a prominence feature, open questions and future directions are discussed.

  7. Functional characterization and multimodal imaging of treatment-naive "quiescent" choroidal neovascularization.

    Science.gov (United States)

    Querques, Giuseppe; Srour, Mayer; Massamba, Nathalie; Georges, Anouk; Ben Moussa, Naima; Rafaeli, Omer; Souied, Eric H

    2013-10-21

    To investigate the multimodal morphological and functional characteristics of treatment-naïve "quiescent" choroidal neovascularization (CNV) secondary to AMD. Eleven patients with treatment-naïve "quiescent" CNV that consecutively presented over a 6-month period, underwent multimodal morphological and functional assessment (including indocyanine green angiography [ICGA], spectral-domain optical coherence tomography [SD-OCT], microperimetry, and preferential hyperacuity perimeter [PHP]). For the purpose of this study, asymptomatic previously untreated CNVs showing absence of intraretinal/subretinal exudation in two consecutive visits (at least 6 months apart) were defined as treatment-naïve "quiescent" CNV. Eleven eyes of 11 patients (9 females; mean age 76.5 ± 8.5 years) were included. On fluorescein angiography (FA), "quiescent" CNVs appeared as late speckled hyperfluorescent lesions lacking well-demarcated borders. Mid-late phase ICGA allowed visualizing the hyperfluorescent "quiescent" CNV network and delineating the plaque. Mean lesion area (mid-late phase ICGA) appeared larger compared with earliest previous examination performed 23.8 ± 16.0 months before (3.24 ± 2.51 mm(2) vs. 3.52 ± 2.46 mm(2), respectively; P = 0.01). SD-OCT revealed, at the site of "quiescent" CNV, an irregularly slightly elevated RPE, without hyporeflective intraretinal/subretinal fluid, showing a major axis in the horizontal plane, which was characterized by collections of moderately reflective material in the sub-RPE space and clear visualization of the hyperreflective Bruch's membrane. Hypergeometric distribution revealed a significant correlation between microperimetry and PHP with respect to locations of "affected areas" (P = 0.001). "Quiescent" CNVs are sub-RPE CNVs secondary to AMD, showing absence of intraretinal/subretinal exudation on repeated OCT. "Quiescent" CNVs enlarge over time and may contribute to local reduced retinal sensitivity and metamorphopsia.

  8. Constraining Metallicity and Age for Massive Quiescent Galaxies in a Redshift Range of 1

    Science.gov (United States)

    Estrada-Carpenter, Vicente; Papovich, Casey J.; Momcheva, Ivelina G.; Brammer, Gabriel; Bridge, Joanna; Dickinson, Mark; Closson Ferguson, Henry; finlator, kristian; Finkelstein, Steven L.; Giavalisco, Mauro; Gosmeyer, Catherine; Livermore, Rachael C.; Long, James; Lotz, Jennifer M.; Kawinwanichakij, Lalitwadee; Pirzkal, Norbert; Quadri, Ryan; Salmon, Brett W.; Tilvi, Vithal; Trump, Jonathan R.; Weiner, Benjamin J.

    2017-01-01

    Using HST/WFC3 grism spectroscopy from the CANDELS Lyman-alpha Emission at Reionization (CLEAR) survey, we constrain the metallicities and ages of massive quiescent galaxies, at z ~ 1.5. CLEAR provides deep spectroscopy (12 HST orbits per pointing) with the WFC3/G102 grism over the wavelength range ~ 7,500 break, Balmer-series lines, and Hg+G features. We stack the G102 spectra of a stellar-mass limited sample of 34 quiescent galaxies, with log(M*/M⊙) > 10 and 1 10.9. The model fits favor higher metallicity for the more massive quiescent galaxies, with Z/Z⊙ ~ 1, with some systematics possibly leading from differences in the stellar population models. Therefore, there is no evidence for significant evolution in metallicity for the most massive quiescent galaxies since z ~ 1.5. The model fits to the lower mass quiescent galaxies favor lower metallicites, Z/Z⊙ ~ 0.4, with an offset of ~ 0.3 dex from the present-day relation (e.g., Galazzi et al. 2005). For quiescent galaxies in this mass range, 10.0 1), or a combination of the two.

  9. Gliosarcoma with prominent smooth muscle component (gliomyosarcoma: A report of 10 cases

    Directory of Open Access Journals (Sweden)

    Manisha Khanna

    2011-01-01

    Full Text Available Background and Aim: Gliosarcoma (GS is an uncommon malignant tumor of the brain, consisting of malignant glial, usually a glioblastoma (GB, as well as sarcomatous component; the latter is usually in the form of fibrosarcoma. We report a series of 10 GSs with prominent smooth muscle component, which is a rare occurrence. Settings and Design: Out of a series of 225 cases of GB admitted in our hospital, 10 were diagnosed as GS with prominent smooth muscle component, gliomyosarcoma (GMS. Materials and Methods: This is an observational study based on the experience with 225 cases of GB, encountered between 1995 and 2008, in our hospital. The tumors showing prominent spindle cell component were stained with reticulin and 20 with strongly positive reticulin stain were diagnosed as GS. They were further studied by immunohistochemical staining for glial fibrillary acidic protein (GFAP, smooth muscle actin (SMA, desmin and factor VIII antigen. Results: Out of 225 cases of GB, 20 were diagnosed as GS. Ten of these showed prominent smooth muscle component and were diagnosed as GMS. They revealed varying degrees of SMA and factor VIII Ag positivity. In the sarcomatous component, SMA and factor VIII positive cells were seen close to the vessel walls as well as away from them. Conclusion: GMS containing prominent smooth muscle component may not be as rare as has been reported in the literature. Both GS and GMS appear to arise from the vessel wall at least in some cases, suggesting their possible vascular origin.

  10. Evidence for quiescent synchrotron emission in the black hole X-ray transient Swift J1357.2–0933

    Directory of Open Access Journals (Sweden)

    Shahbaz T.

    2013-12-01

    Full Text Available We present high time-resolution optical and infrared observations of the edge-on black hole X-ray transient Swift J1357.2-0933. Our data taken in 2012 shows the system to be at its pre-outburst magnitude and so the system is in quiescence. In contrast to other X-ray transients, the quiescent light curves of Swift J1357.2-0933 do not show the secondary star’s ellipsoidal modulation. The optical and infrared light curves is dominated by variability with an optical fractional rms of about 20 per cent, much larger than what is observed in other systems. The quiescent ultraviolet to mid-IR spectral energy distribution in quiescence is dominated by a nonthermal component with a power–law index of −1.4, (the broad-band rms SED has a similar index which arises from optically thin synchrotron emission from a jet; the lack of a peak in the spectral energy distribution rules out advection-dominated models (based on [19].

  11. The quiescent state of the accreting X-ray pulsar SAX J2103.5+4545

    CERN Document Server

    Reig, P; Zezas, A

    2014-01-01

    We present an X-ray timing and spectral analysis of the Be/X-ray binary SAX J2103.5+4545 at a time when the Be star's circumstellar disk had disappeared and thus the main reservoir of material available for accretion had extinguished. In this very low optical state, pulsed X-ray emission was detected at a level of L_X~10^{33} erg/s. This is the lowest luminosity at which pulsations have ever been detected in an accreting pulsar. The derived spin period is 351.13 s, consistent with previous observations. The source continues its overall long-term spin-up, which reduced the spin period by 7.5 s since its discovery in 1997. The X-ray emission is consistent with a purely thermal spectrum, represented by a blackbody with kT=1 keV. We discuss possible scenarios to explain the observed quiescent luminosity and conclude that the most likely mechanism is direct emission resulting from the cooling of the polar caps, heated either during the most recent outburst or via intermittent accretion in quiescence.

  12. Further Constraints on Thermal Quiescent X-ray Emission from SAX J1808.4-3658

    CERN Document Server

    Heinke, C O; Wijnands, R; Deloye, C J; Taam, R E

    2008-01-01

    We observed SAX J1808.4-3658 (1808), the first accreting millisecond pulsar, in deep quiescence with XMM-Newton and (near-simultaneously) Gemini-South. The X-ray spectrum of 1808 is similar to that observed in quiescence in 2001 and 2006, describable by an absorbed power-law with photon index 1.74+-0.11 and unabsorbed X-ray luminosity L_X=7.9+-0.7*10^{31} ergs/s, for N_H=1.3*10^{21} cm^{-2}. Fitting all the quiescent XMM-Newton X-ray spectra with a power-law, we constrain any thermally emitting neutron star with a hydrogen atmosphere to have a temperature less than 30 eV and L_{NS}(0.01-10 keV)<6.2*10^{30} ergs/s. A thermal plasma model also gives an acceptable fit to the continuum. Adding a neutron star component to the plasma model produces less stringent constraints on the neutron star; a temperature of 36^{+4}_{-8} eV and L_{NS}(0.01-10 keV)=1.3^{+0.6}_{-0.8}*10^{31} ergs/s. In the framework of the current theory of neutron star heating and cooling, the constraints on the thermal luminosity of 1808 and...

  13. A SUBSTANTIAL POPULATION OF MASSIVE QUIESCENT GALAXIES AT z ∼ 4 FROM ZFOURGE

    Energy Technology Data Exchange (ETDEWEB)

    Straatman, Caroline M. S.; Labbé, Ivo [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Spitler, Lee R. [Department of Physics and Astronomy, Faculty of Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Allen, Rebecca; Glazebrook, Karl; Kacprzak, Glenn G. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Altieri, Bruno [European Space Astronomy Centre (ESAC)/ESA, Villanueva de la Cañada, 28691, Madrid (Spain); Brammer, Gabriel B. [European Southern Observatory, Alonso de Córdova 3107, Casilla 19001, Vitacura, Santiago (Chile); Dickinson, Mark; Inami, Hanae [National Optical Astronomy Observatory, Tucson, AZ (United States); Van Dokkum, Pieter [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Kawinwanichakij, Lalit; Mehrtens, Nicola; Papovich, Casey [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); Kelson, Daniel D.; McCarthy, Patrick J.; Monson, Andy; Murphy, David; Persson, S. Eric; Quadri, Ryan, E-mail: straatman@strw.leidenuniv.nl [Carnegie Observatories, Pasadena, CA 91101 (United States); and others

    2014-03-01

    We report the likely identification of a substantial population of massive M ∼ 10{sup 11} M {sub ☉} galaxies at z ∼ 4 with suppressed star formation rates (SFRs), selected on rest-frame optical to near-IR colors from the FourStar Galaxy Evolution Survey (ZFOURGE). The observed spectral energy distributions show pronounced breaks, sampled by a set of near-IR medium-bandwidth filters, resulting in tightly constrained photometric redshifts. Fitting stellar population models suggests large Balmer/4000 Å breaks, relatively old stellar populations, large stellar masses, and low SFRs, with a median specific SFR of 2.9 ± 1.8 × 10{sup –11} yr{sup –1}. Ultradeep Herschel/PACS 100 μm, 160 μm and Spitzer/MIPS 24 μm data reveal no dust-obscured SFR activity for 15/19(79%) galaxies. Two far-IR detected galaxies are obscured QSOs. Stacking the far-IR undetected galaxies yields no detection, consistent with the spectral energy distribution fit, indicating independently that the average specific SFR is at least 10 × smaller than that of typical star-forming galaxies at z ∼ 4. Assuming all far-IR undetected galaxies are indeed quiescent, the volume density is 1.8 ± 0.7 × 10{sup –5} Mpc{sup –3} to a limit of log{sub 10} M/M {sub ☉} ≥ 10.6, which is 10 × and 80 × lower than at z = 2 and z = 0.1. They comprise a remarkably high fraction (∼35%) of z ∼ 4 massive galaxies, suggesting that suppression of star formation was efficient even at very high redshift. Given the average stellar age of 0.8 Gyr and stellar mass of 0.8 × 10{sup 11} M {sub ☉}, the galaxies likely started forming stars before z = 5, with SFRs well in excess of 100 M {sub ☉} yr{sup –1}, far exceeding that of similarly abundant UV-bright galaxies at z ≥ 4. This suggests that most of the star formation in the progenitors of quiescent z ∼ 4 galaxies was obscured by dust.

  14. Relationship between heart rate and quiescent interval of the cardiac cycle in children using MRI.

    Science.gov (United States)

    Zhang, Wei; Bogale, Saivivek; Golriz, Farahnaz; Krishnamurthy, Rajesh

    2017-07-25

    Imaging the heart in children comes with the challenge of constant cardiac motion. A prospective electrocardiography-triggered CT scan allows for scanning during a predetermined phase of the cardiac cycle with least motion. This technique requires knowing the optimal quiescent intervals of cardiac cycles in a pediatric population. To evaluate high-temporal-resolution cine MRI of the heart in children to determine the relationship of heart rate to the optimal quiescent interval within the cardiac cycle. We included a total of 225 consecutive patients ages 0-18 years who had high-temporal-resolution cine steady-state free-precession sequence performed as part of a magnetic resonance imaging (MRI) or magnetic resonance angiography study of the heart. We determined the location and duration of the quiescent interval in systole and diastole for heart rates ranging 40-178 beats per minute (bpm). We performed the Wilcoxon signed rank test to compare the duration of quiescent interval in systole and diastole for each heart rate group. The duration of the quiescent interval at heart rates bpm and >90 bpm was significantly longer in diastole and systole, respectively (Pbpm [P=.02]). For heart rates 80-89 bpm, diastolic interval was longer than systolic interval, but the difference was not statistically significant (P=.06). We created a chart depicting optimal quiescent intervals across a range of heart rates that could be applied for prospective electrocardiography-triggered CT imaging of the heart. The optimal quiescent interval at heart rates bpm is in diastole and at heart rates ≥90 bpm is in systole. The period of quiescence at heart rates 80-89 bpm is uniformly short in systole and diastole.

  15. The contribution of young core-collapse supernova remnants to the X-ray emission near quiescent supermassive black holes

    CERN Document Server

    Rimoldi, Alex; Costantini, Elisa; Zwart, Simon Portegies

    2015-01-01

    Appreciable star formation, and, therefore, numerous massive stars, are frequently found near supermassive black holes (SMBHs). As a result, core-collapse supernovae in these regions should also be expected. In this paper, we consider the observational consequences of predicting the fate of supernova remnants (SNRs) in the sphere of influence of quiescent SMBHs. We present these results in the context of `autarkic' nuclei, a model that describes quiescent nuclei as steady-state and self-sufficient environments where the SMBH accretes stellar winds with no appreciable inflow of material from beyond the sphere of influence. These regions have properties such as gas density that scale with the mass of the SMBH. Using predictions of the X-ray lifetimes of SNRs originating in the sphere of influence, we make estimates of the number of core collapse SNRs present at a given time. With the knowledge of lifetimes of SNRs and their association with young stars, we predict a number of core-collapse SNRs that grows from ...

  16. DIRECT SPATIAL ASSOCIATION OF AN X-RAY FLARE WITH THE ERUPTION OF A SOLAR QUIESCENT FILAMENT

    Energy Technology Data Exchange (ETDEWEB)

    Holman, Gordon D.; Foord, Adi, E-mail: gordon.d.holman@nasa.gov [Code 671, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2015-05-10

    Solar flares primarily occur in active regions. Hard X-ray flares have been found to occur only in active regions. They are often associated with the eruption of active region filaments and coronal mass ejections (CMEs). CMEs can also be associated with the eruption of quiescent filaments, not located in active regions. Here we report the first identification of a solar X-ray flare outside an active region observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The X-ray emission was directly associated with the eruption of a long, quiescent filament and fast CME. Images from RHESSI show this flare emission to be located along a section of the western ribbon of the expanding, post-eruption arcade. EUV images from the Solar Dynamics Observatory Atmospheric Imaging Assembly show no connection between this location and nearby active regions. Therefore the flare emission is found not to be located in or associated with an active region. However, a nearby, small, magnetically strong dipolar region provides a likely explanation for the existence and location of the flare X-ray emission. This emerging dipolar region may have also triggered the filament eruption.

  17. The Scaling of Stellar Mass and Central Stellar Velocity Dispersion for Quiescent galaxies at z < 0.7

    CERN Document Server

    Zahid, Jabran; Fabricant, Daniel; Hwang, Ho Seong

    2016-01-01

    We examine the relation between stellar mass and central stellar velocity dispersion-the M-sigma relation-for massive quiescent galaxies at z85%) and we consistently measure the stellar mass and velocity dispersion for the two samples. The M-sigma relation and its scatter are independent of redshift with sigma ~ M^0.3 for M > 10^10.3 solar masses. The measured slope of the M-sigma relation is the same as the scaling between the total halo mass and the dark matter halo velocity dispersion obtained by N-body simulations. This consistency suggests that massive quiescent galaxies are virialized systems where the central dark matter concentration is either a constant or negligible fraction of the stellar mass. The relation between the total galaxy mass (stellar + dark matter) and the central stellar velocity dispersion is consistent with the observed relation between the total mass of a galaxy cluster and the velocity dispersion of the cluster members. This result suggests that the central stellar velocity dispers...

  18. Identification of the optical and quiescent counterparts to the bright X-ray transient in NGC 6440

    CERN Document Server

    in 't Zand, J J M; Pooley, D; Verbunt, F; Wijnands, R; Lewin, W H G

    2001-01-01

    After 3 years of quiescence, the globular cluster NGC 6440 exhibited a bright transient X-ray source turning on in August 2001, as noted with the RXTE All-Sky Monitor. We carried out a short target of opportunity observation with the Chandra X-ray Observatory and are able to associate the transient with the brightest of 24 X-ray sources detected during quiescence in July 2000 with Chandra. Furthermore, we securely identify the optical counterpart and determine that the 1998 X-ray outburst in NGC 6440 was from the same object. This is the first time that an optical counterpart to a transient in a globular cluster is securely identified. Since the transient is a type I X-ray burster, it is established that the compact accretor is a neutron star. Thus, this transient provides an ideal case to study the quiescent emission in the optical and X-ray of a transiently accreting neutron star while knowing the distance and reddening accurately. One model that fits the quiescent spectrum is an absorbed power law plus neu...

  19. Ages and metallicities for quiescent galaxies in the Shapley Supercluster: Driving parameters of the stellar populations

    CERN Document Server

    Smith, Russell J; Hudson, Michael J

    2009-01-01

    We use high signal-to-noise spectroscopy for a sample of 232 quiescent galaxies in the Shapley Supercluster, to investigate how their stellar populations depend on velocity dispersion, luminosity and stellar mass. The sample spans a large range in velocity dispersion (sigma from 30-300 km/s) and in luminosity (M_R from -18.7 to -23.2). Estimates of age, total metallicity (Z/H) and alpha-element abundance ratio (a/Fe) were derived from absorption-line analysis, using single-burst models. Age, Z/H and a/Fe are all correlated positively with velocity dispersion, but we also find significant residual trends with luminosity: at given sigma, the brighter galaxies are younger, less alpha-enriched, and have higher Z/H. At face value, these results might suggest that the stellar populations depend on stellar mass as well as on velocity dispersion. However, we show that the observed trends can be reproduced by models in which the stellar populations depend systematically only on sigma, and are independent of stellar ma...

  20. Gas hydrate fast nucleation from melting ice and quiescent growth along vertical heat transfer tube

    Institute of Scientific and Technical Information of China (English)

    XIE; Yingming; GUO; Kaihua; LIANG; Deqing; FAN; Shuanshi

    2005-01-01

    During the observation of HCFC141b gas hydrate growth processes outside a vertical heat transfer tube, two exciting phenomena were found: fast nucleation of gas hydrate from melting ice, and the spontaneous permeation of water into the guest phases along the surface of heat transfer tube to form gas hydrate continuously. These two phenomena were explained with Zhou & Sloan's hypothesis and the theory of surface free energy respectively, and a novel method of gas hydrate formation was presented--gas hydrate fast nucleation from melting ice and quiescent growth along heat transfer tube. There is no mechanic stirring in this method, the formed gas hydrates are compact, the ratio of unreacted interstitial water is little, which overcome the drawback of high energy cost and high ratio of unreacted interstitial water among the formed gas hydrates in the system with mechanic stirring. This finding will benefit the gas hydrate application technologies such as natural gas storage technology or cool storage technology with gas hydrate.

  1. The quiescent light curve and orbital period of GRO$\\sim$J0422+32

    CERN Document Server

    Chevalier, C; Chevalier, Claude; Ilovaisky, Sergio A

    1996-01-01

    CCD photometry of the black hole candidate GRO~J0422+32 in quiescence, obtained at Haute-Provence from 1994 November to 1995 February, reveals a double-wave modulation at a period close to the value we found during outbursts and also close to one of the possible periods derived by Filippenko, Matheson and Ho (1995) from spectroscopic observations with the W. M. Keck 10-m telescope. A period of 0.212140 \\pm 0.000003 d (5.09136 \\pm 0.00007 h) fits all our photometric data from 1993 January to 1995 February and yields a minimum in our light curves at the inferior conjunction of the M star, as determined from the radial velocity data of Filippenko et al. (1995). The quiescent R_{c} band light curve exhibits a changing asymmetry of shape and a variable amplitude. On two consecutive nights the source was found constant to within \\pm 0.05 mag, suggesting an upper limit on the ellipsoidal effect in this band.

  2. Human mesenchymal stem cells promote survival of T cells in a quiescent state.

    Science.gov (United States)

    Benvenuto, Federica; Ferrari, Stefania; Gerdoni, Ezio; Gualandi, Francesca; Frassoni, Francesco; Pistoia, Vito; Mancardi, Gianluigi; Uccelli, Antonio

    2007-07-01

    Mesenchymal stem cells (MSC) are part of the bone marrow that provides signals supporting survival and growth of bystander hematopoietic stem cells (HSC). MSC modulate also the immune response, as they inhibit proliferation of lymphocytes. In order to investigate whether MSC can support survival of T cells, we investigated MSC capacity of rescuing T lymphocytes from cell death induced by different mechanisms. We observed that MSC prolong survival of unstimulated T cells and apoptosis-prone thymocytes cultured under starving conditions. MSC rescued T cells from activation induced cell death (AICD) by downregulation of Fas receptor and Fas ligand on T cell surface and inhibition of endogenous proteases involved in cell death. MSC dampened also Fas receptor mediated apoptosis of CD95 expressing Jurkat leukemic T cells. In contrast, rescue from AICD was not associated with a significant change of Bcl-2, an inhibitor of apoptosis induced by cell stress. Accordingly, MSC exhibited a minimal capacity of rescuing Jurkat cells from chemically induced apoptosis, a process disrupting the mitochondrial membrane potential regulated by Bcl-2. These results suggest that MSC interfere with the Fas receptor regulated process of programmed cell death. Overall, MSC can inhibit proliferation of activated T cells while supporting their survival in a quiescent state, providing a model of their activity inside the HSC niche. Disclosure of potential conflicts of interest is found at the end of this article.

  3. Origin of the concept of the quiescent centre of plant roots.

    Science.gov (United States)

    Barlow, Peter W

    2016-09-01

    Concepts in biology feed into general theories of growth, development and evolution of organisms and how they interact with the living and non-living components of their environment. A well-founded concept clarifies unsolved problems and serves as a focus for further research. One such example of a constructive concept in the plant sciences is that of the quiescent centre (QC). In anatomical terms, the QC is an inert group of cells maintained within the apex of plant roots. However, the evidence that established the presence of a QC accumulated only gradually, making use of strands of different types of observations, notably from geometrical-analytical anatomy, radioisotope labelling and autoradiography. In their turn, these strands contributed to other concepts: those of the mitotic cell cycle and of tissue-related cell kinetics. Another important concept to which the QC contributed was that of tissue homeostasis. The general principle of this last-mentioned concept is expressed by the QC in relation to the recovery of root growth following a disturbance to cell proliferation; the resulting activation of the QC provides new cells which not only repair the root meristem but also re-establish a new QC.

  4. NUMERICAL STUDY ON IN SITU PROMINENCE FORMATION BY RADIATIVE CONDENSATION IN THE SOLAR CORONA

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, T.; Yokoyama, T., E-mail: kaneko@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan)

    2015-06-10

    We propose an in situ formation model for inverse-polarity solar prominences and demonstrate it using self-consistent 2.5 dimensional MHD simulations, including thermal conduction along magnetic fields and optically thin radiative cooling. The model enables us to form cool dense plasma clouds inside a flux rope by radiative condensation, which is regarded as an inverse-polarity prominence. Radiative condensation is triggered by changes in the magnetic topology, i.e., formation of the flux rope from the sheared arcade field, and by thermal imbalance due to the dense plasma trapped inside the flux rope. The flux rope is created by imposing converging and shearing motion on the arcade field. Either when the footpoint motion is in the anti-shearing direction or when heating is proportional to local density, the thermal state inside the flux rope becomes cooling-dominant, leading to radiative condensation. By controlling the temperature of condensation, we investigate the relationship between the temperature and density of prominences and derive a scaling formula for this relationship. This formula suggests that the proposed model reproduces the observed density of prominences, which is 10–100 times larger than the coronal density. Moreover, the time evolution of the extreme ultraviolet emission synthesized by combining our simulation results with the response function of the Solar Dynamics Observatory Atmospheric Imaging Assembly filters agrees with the observed temporal and spatial intensity shift among multi-wavelength extreme ultraviolet emission during in situ condensation.

  5. UNDERSTANDING THE MG II AND Hα SPECTRA IN A HIGHLY DYNAMICAL SOLAR PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Heinzel, P. [Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov (Czech Republic); Schmieder, B.; Mein, N. [Observatoire de Paris, LESIA, UMR 8109 (CNRS), F-92195 Meudon (France); Gunár, S., E-mail: pheinzel@asu.cas.cz [School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews KY 16 9SS (United Kingdom)

    2015-02-10

    Mg ii h and k and Hα spectra in a dynamical prominence have been obtained along the slit of the Interface Region Imaging Spectrograph (IRIS) and with the Meudon Multi-channel Subtractive Double Pass spectrograph on 2013 September 24, respectively. Single Mg ii line profiles are not much reversed, while at some positions along the IRIS slit the profiles show several discrete peaks that are Doppler-shifted. The intensity of these peaks is generally decreasing with their increasing Doppler shift. We interpret this unusual behavior as being due to the Doppler dimming effect. We discuss the possibility to interpret the unreversed single profiles by using a two-dimensional (2D) model of the entire prominence body with specific radiative boundary conditions. We have performed new 2D isothermal–isobaric modeling of both Hα and Mg ii lines and show the ability of such models to account for the line profile variations as observed. However, the Mg ii line-center intensities require the model with a temperature increase toward the prominence boundary. We show that even simple one-dimensional (1D) models with a prominence-to-corona transition region (PCTR) fit the observed Mg ii and Hα lines quite well, while the isothermal–isobaric models (1D or 2D) are inconsistent with simultaneous observations in the Mg ii h and k and Hα lines, meaning that the Hα line provides a strong additional constraint on the modeling. IRIS far-UV detection of the C ii lines in this prominence seems to provide a direct constraint on the PCTR part of the model.

  6. Polar migration of prominences and the inversion of the polar magnetic field of the sun in the 11th and 12th solar cycles (1869 - 1885).

    Science.gov (United States)

    Makarov, V. I.

    The trajectories of the polar migration of prominences are calculated on the basis of spectroscopic observations of prominences during 1869 - 1885. The epoch of the polarity inversion of the polar magnetic field is determined. Three "waves" of migration of polar prominences were observed in the southern hemisphere in the 12th solar cycle whose velocities were 3.9, 7.0 and 8.3 m sec-1. In the northern hemisphere only one "wave" of migration was observed whose velocity was 4.0 m sec-1. The 12th solar cycle is similar to the 14th solar cycle from the point of view of polar migration of prominences.

  7. The Most Prominent Roles of an ESP Teacher

    Science.gov (United States)

    Ghafournia, Narjes; Sabet, Shokoofeh Ahmadian

    2014-01-01

    One prominent feature of many ESP (English for Specific Purposes) courses, which make them rather different from EGP (English for General Purposes) courses, is the presence of adult learners, who are primary workers and secondary learners. As ESP is a highly learner-cantered approach, paying close attention to the multidimensional needs of…

  8. The Prominence of Referring Expressions: Message and Lexical Level Effects

    Science.gov (United States)

    Lam, Tuan Q.

    2012-01-01

    In conversation, speakers produce some words with greater intensity, longer duration, and higher fundamental frequency (F0) than other words. By making different words in a sentence more prominent than other words, a speaker can change the meaning implied by a sentence. This thesis explores the relationship between processing in the language…

  9. A-B Distinction in a Sample of Prominent Psychotherapists

    Science.gov (United States)

    Geller, Jesse D.; Berzins, Juris I.

    1976-01-01

    A sample of prominent psychotherapists were asked to fill out the A-B therapist "type" scale and comment on their possible differential effectiveness in treating schizoid/schizophrenic versus neurotic patients. The data suggest that B therapists desire and seek more complex and exciting sensory-cognitive inputs during therapy hours than A…

  10. The Variable Quiescent X-Ray Emission of the Neutron Star Transient XTE J1701-462

    Science.gov (United States)

    Fridriksson, Joel K.; Homan, J.; Wijnands, R.; Cackett, E. M.; Degenaar, N.; Mendez, M.; Altamirano, D.; Brown, E. F.; Belloni, T. M.; Lewin, W. H. G.

    2011-01-01

    We have monitored the cooling of the neutron star in the transient low-mass X-ray binary XTE J1701-462 with Chandra and XMM-Newton since the source entered quiescence in 2007 after an exceptionally luminous 19-month outburst. A recent Chandra observation made almost 1200 days into quiescence indicates that the neutron star crust is likely still slowly cooling toward thermal equilibrium with the core. The current surface temperature is high compared to other quiescent neutron star transients, with an implied bolometric thermal flux of 5×1033 erg/s. The overall cooling curve seems to have followed a broken power-law shape as predicted by theoretical models, although the observed break is considerably earlier than what is expected from theory. After rapid cooling during the first 200 days of quiescence---strongly indicating a highly conductive neutron star crust---the source unexpectedly showed a large temporary increase in both thermal and non-thermal flux. Prompted by this we conducted a Swift monitoring program of the source during April-October 2010, with short observations taking place once every two weeks. During the program we detected short-term flares up to at least 1×1035 erg/s, a factor of 20 higher than the normal quiescent level. We compare this flaring---presumably arising from episodic low-level accretion---with the behavior observed from faint Galactic transients, and discuss whether flaring in XTE J1701-462 can significantly affect the cooling of the source and whether it can to some extent explain the high temperature of the neutron star core implied by our Chandra observations.

  11. Feasibility of reduced gravity experiments involving quiescent, uniform particle cloud combustion

    Science.gov (United States)

    Ross, Howard D.; Facca, Lily T.; Berlad, Abraham L.; Tangirala, Venkat

    1989-01-01

    The study of combustible particle clouds is of fundamental scientific interest as well as a practical concern. The principal scientific interests are the characteristic combustion properties, especially flame structure, propagation rates, stability limits, and the effects of stoichiometry, particle type, transport phenomena, and nonadiabatic processes on these properties. The feasibility tests for the particle cloud combustion experiment (PCCE) were performed in reduced gravity in the following stages: (1) fuel particles were mixed into cloud form inside a flammability tube; (2) when the concentration of particles in the cloud was sufficiently uniform, the particle motion was allowed to decay toward quiescence; (3) an igniter was energized which both opened one end of the tube and ignited the suspended particle cloud; and (4) the flame proceeded down the tube length, with its position and characteristic features being photographed by high-speed cameras. Gravitational settling and buoyancy effects were minimized because of the reduced gravity enviroment in the NASA Lewis drop towers and aircraft. Feasibility was shown as quasi-steady flame propagation which was observed for fuel-rich mixtures. Of greatest scientific interest is the finding that for near-stoichiometric mixtures, a new mode of flame propagation was observed, now called a chattering flame. These flames did not propagate steadily through the tube. Chattering modes of flame propagation are not expected to display extinction limits that are the same as those for acoustically undisturbed, uniform, quiescent clouds. A low concentration of fuel particles, uniformly distributed in a volume, may not be flammable but may be made flammable, as was observed, through induced segregation processes. A theory was developed which showed that chattering flame propagation was controlled by radiation from combustion products which heated the successive discrete laminae sufficiently to cause autoignition.

  12. The Assembly Histories of Quiescent Galaxies since z=0.7 from Absorption Line Spectroscopy

    CERN Document Server

    Choi, Jieun; Moustakas, John; Graves, Genevieve J; Holden, Bradford P; Brodwin, Mark; Brown, Michael J I; van Dokkum, Pieter G

    2014-01-01

    We present results from modeling the optical spectra of a large sample of quiescent galaxies between 0.11 indicate the inhomogeneous nature of the z<0.7 quiescent population. The data also permit the addition of newly-quenched galaxies at masses below ~10^10.5 Msun at z<0.7. Additionally, we analyze very deep Keck DEIMOS spectra of the two brightest quiescent galaxies in a cluster at z=0.83. There is tentative evidence that these galaxies are older than their counterparts in low-density environments. In an Appendix, we demonstrate that our full spectrum modeling technique allows for accurate and reliable modeling of galaxy spectra to low S/N and/or low spectral resolution.

  13. Efficient regeneration by activation of neurogenesis in homeostatically quiescent regions of the adult vertebrate brain.

    Science.gov (United States)

    Berg, Daniel A; Kirkham, Matthew; Beljajeva, Anna; Knapp, Dunja; Habermann, Bianca; Ryge, Jesper; Tanaka, Elly M; Simon, András

    2010-12-01

    In contrast to mammals, salamanders and teleost fishes can efficiently repair the adult brain. It has been hypothesised that constitutively active neurogenic niches are a prerequisite for extensive neuronal regeneration capacity. Here, we show that the highly regenerative salamander, the red spotted newt, displays an unexpectedly similar distribution of active germinal niches with mammals under normal physiological conditions. Proliferation zones in the adult newt brain are restricted to the forebrain, whereas all other regions are essentially quiescent. However, ablation of midbrain dopamine neurons in newts induced ependymoglia cells in the normally quiescent midbrain to proliferate and to undertake full dopamine neuron regeneration. Using oligonucleotide microarrays, we have catalogued a set of differentially expressed genes in these activated ependymoglia cells. This strategy identified hedgehog signalling as a key component of adult dopamine neuron regeneration. These data show that brain regeneration can occur by activation of neurogenesis in quiescent brain regions.

  14. Are quiescent galaxies truly devoid of star formation? The mid-, far-infrared and radio properties of quiescent galaxies at z = 0.1 - 3

    Science.gov (United States)

    Man, Allison W. S.

    Quiescent galaxy candidates are typically identified by their low unobscured star formation rates from deep field photometric surveys. However, their selection technique relies on the assumption of a universal dust attenuation curve. It is important to verify the selection through independent SFR indicators at longer wavelengths. Current mid-, far-infrared and radio surveys are limited to detecting only galaxies with very strong star formation or AGN activity. Here, I present the first comprehensive stacking results across mid-, far-infrared and radio wavelengths using Spitzer, Herschel and VLA data in the COSMOS field (Man et al. 2014). We find that the rest-frame NUV-r and r-J color criteria, combined with low 24 μm emission, provides a robust selection of truly quiescent galaxies out to z = 3. Additionally, we find evidence of radio emission in excess of the expected total star formation in quiescent galaxies at z ~ 0-1.5, indicative of a ubiquitous presence of low-luminosity radio AGN among them.

  15. The ALHAMBRA survey: B-band luminosity function of quiescent and star-forming galaxies at 0.2 ≤ z < 1 by PDF analysis

    Science.gov (United States)

    López-Sanjuan, C.; Tempel, E.; Benítez, N.; Molino, A.; Viironen, K.; Díaz-García, L. A.; Fernández-Soto, A.; Santos, W. A.; Varela, J.; Cenarro, A. J.; Moles, M.; Arnalte-Mur, P.; Ascaso, B.; Montero-Dorta, A. D.; Pović, M.; Martínez, V. J.; Nieves-Seoane, L.; Stefanon, M.; Hurtado-Gil, Ll.; Márquez, I.; Perea, J.; Aguerri, J. A. L.; Alfaro, E.; Aparicio-Villegas, T.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Cristóbal-Hornillos, D.; González Delgado, R. M.; Husillos, C.; Infante, L.; Masegosa, J.; del Olmo, A.; Prada, F.; Quintana, J. M.

    2017-03-01

    Aims: Our goal is to study the evolution of the B-band luminosity function (LF) since z 1 using ALHAMBRA data. Methods: We used the photometric redshift and the I-band selection magnitude probability distribution functions (PDFs) of those ALHAMBRA galaxies with I ≤ 24 mag to compute the posterior LF. We statistically studied quiescent and star-forming galaxies using the template information encoded in the PDFs. The LF covariance matrix in redshift - magnitude - galaxy type space was computed, including the cosmic variance. That was estimated from the intrinsic dispersion of the LF measurements in the 48 ALHAMBRA sub-fields. The uncertainty due to the photometric redshift prior is also included in our analysis. Results: We modelled the LF with a redshift-dependent Schechter function affected by the same selection effects than the data. The measured ALHAMBRA LF at 0.2 ≤ zjB of star-forming galaxies, and a factor 1.25 ± 0.16 increase in the jB of quiescent ones since z = 1, confirming the continuous build-up of the quiescent population with cosmic time. The contribution of the faint quiescent population to jB increases from 3% at z = 1 to 6% at z = 0. The developed methodology will be applied to future multi-filter surveys such as J-PAS. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto (CAHA), jointly operated by the Max-Planck-Institut für Astronomie (MPIA) at Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC)

  16. Observation

    Science.gov (United States)

    Patell, Hilla

    2016-01-01

    In order to achieve the goal of observation, preparation of the adult, the observer, is necessary. This preparation, says Hilla Patell, requires us to "have an appreciation of the significance of the child's spontaneous activities and a more thorough understanding of the child's needs." She discusses the growth of both the desire to…

  17. Observation

    Science.gov (United States)

    Kripalani, Lakshmi A.

    2016-01-01

    The adult who is inexperienced in the art of observation may, even with the best intentions, react to a child's behavior in a way that hinders instead of helping the child's development. Kripalani outlines the need for training and practice in observation in order to "understand the needs of the children and...to understand how to remove…

  18. Premalignant quiescent melanocytic nevi do not express the MHC class I chain-related protein A

    Directory of Open Access Journals (Sweden)

    Mercedes B. Fuertes

    2011-08-01

    Full Text Available The MHC class I chain-related protein A (MICA is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK cells, CD8+ aßTCR and ?dTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-? secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease- induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples as well as in normal skin, benign lesions (seborrheic keratosis, premalignant lesions (actinic keratosis and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.

  19. PHABULOSA controls the quiescent center-independent root meristem activities in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Jose Sebastian

    2015-03-01

    Full Text Available Plant growth depends on stem cell niches in meristems. In the root apical meristem, the quiescent center (QC cells form a niche together with the surrounding stem cells. Stem cells produce daughter cells that are displaced into a transit-amplifying (TA domain of the root meristem. TA cells divide several times to provide cells for growth. SHORTROOT (SHR and SCARECROW (SCR are key regulators of the stem cell niche. Cytokinin controls TA cell activities in a dose-dependent manner. Although the regulatory programs in each compartment of the root meristem have been identified, it is still unclear how they coordinate one another. Here, we investigate how PHABULOSA (PHB, under the posttranscriptional control of SHR and SCR, regulates TA cell activities. The root meristem and growth defects in shr or scr mutants were significantly recovered in the shr phb or scr phb double mutant, respectively. This rescue in root growth occurs in the absence of a QC. Conversely, when the modified PHB, which is highly resistant to microRNA, was expressed throughout the stele of the wild-type root meristem, root growth became very similar to that observed in the shr; however, the identity of the QC was unaffected. Interestingly, a moderate increase in PHB resulted in a root meristem phenotype similar to that observed following the application of high levels of cytokinin. Our protoplast assay and transgenic approach using ARR10 suggest that the depletion of TA cells by high PHB in the stele occurs via the repression of B-ARR activities. This regulatory mechanism seems to help to maintain the cytokinin homeostasis in the meristem. Taken together, our study suggests that PHB can dynamically regulate TA cell activities in a QC-independent manner, and that the SHR-PHB pathway enables a robust root growth system by coordinating the stem cell niche and TA domain.

  20. The X-ray Polarization Signature of Quiescent Magnetars: Effect of Magnetospheric Scattering and Vacuum Polarization

    Science.gov (United States)

    Fernández, Rodrigo; Davis, Shane W.

    2011-04-01

    In the magnetar model, the quiescent non-thermal soft X-ray emission from anomalous X-ray pulsars and soft gamma repeaters is thought to arise from resonant Comptonization of thermal photons by charges moving in a twisted magnetosphere. Robust inference of physical quantities from observations is difficult, because the process depends strongly on geometry, and current understanding of the magnetosphere is not very deep. The polarization of soft X-ray photons is an independent source of information, and its magnetospheric imprint remains only partially explored. In this paper, we calculate how resonant cyclotron scattering would modify the observed polarization signal relative to the surface emission, using a multidimensional Monte Carlo radiative transfer code that accounts for the gradual coupling of polarization eigenmodes as photons leave the magnetosphere. We employ a globally twisted, self-similar, force-free magnetosphere with a power-law momentum distribution, assume a blackbody spectrum for the seed photons, account for general relativistic light deflection close to the star, and assume that vacuum polarization dominates the dielectric properties of the magnetosphere. The latter is a good approximation if the pair multiplicity is not much larger than unity. Phase-averaged polarimetry is able to provide a clear signature of the magnetospheric reprocessing of thermal photons and to constrain mechanisms generating the thermal emission. Phase-resolved polarimetry, in addition, can characterize the spatial extent and magnitude of the magnetospheric twist angle at ~100 stellar radii, and discern between uni- or bidirectional particle energy distributions, almost independently of every other parameter in the system. We discuss prospects for detectability with the Gravity and Extreme Magnetism (GEMS) mission.

  1. Premalignant quiescent melanocytic nevi do not express the MHC class I chain-related protein A.

    Science.gov (United States)

    Fuertes, Mercedes B; Rossi, Lucas E; Peralta, Carlos M; Cabrera, Hugo N; Allevato, Miguel A; Zwirner, Norberto W

    2011-01-01

    The MHC class I chain-related protein A (MICA) is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK) cells, CD8+ abTCR and gdTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-g secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease-induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi) remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples) as well as in normal skin, benign lesions (seborrheic keratosis), premalignant lesions (actinic keratosis) and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.

  2. Advancing the Physics Basis of Quiescent H-mode through Exploration of ITER Relevant Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, W. M. [PPPL; Burrell, K. H. [General Atomics; Fenstermacher, M. E. [LLNL; Garofalo, A. M. [General Atomics; Grierson, B. A. [PPPL; Loarte, A. [ITER; McKee, G. R. [U of Wisc, Madison; Nazikian, R. [PPPL; Snyder, B. P. [General Atomics

    2014-09-01

    Recent experiments on DIII-D have overcome a long-standing limitation in accessing quiescent H-mode (QH-mode), a high confinement state of the plasma that does not exhibit the explosive instabilities associated with edge localized modes (ELMs). In the past, QH-mode was associated with low density operation, but has now been extended to high normalized densities compatible with operation envisioned for ITER. Through the use of strong shaping, QH-mode plasmas have been maintained at high densities, both absolute (ηe ≈ 7 × 1019 m—3) and normalized Greenwald fraction (ηe/ηG > 0:7) . In these plasmas, the pedestal can evolve to very high pressures and current as the density is increased. Calculations of the pedestal height and width from the EPED model are quantitatively consistent with the experimental observed evolution with density. The comparison of the dependence of the maximum density threshold for QH-mode with plasma shape help validate the underlying theoretical peeling-ballooning models describing ELM stability. High density QH-mode operation with strong shaping has allowed stable access to a previously predicted regime of very high pedestal dubbed \\Super H-mode". In general, QH-mode is found to achieve ELM-stable operation while maintaining adequate impurity exhaust, due to the enhanced impurity transport from an edge harmonic oscillation, thought to be a saturated kink- peeling mode driven by rotation shear. In addition, the impurity confinement time is not affected by rotation, even though the energy confinement time and measured E Χ B shear is observed to increase at low toroidal rotation. Together with demonstrations of high beta, high confinement and low q95 for many energy confinement times, these results suggest QH-mode as a potentially attractive operating scenario for ITER's Q=10 mission.

  3. PHABULOSA controls the quiescent center-independent root meristem activities in Arabidopsis thaliana.

    Science.gov (United States)

    Sebastian, Jose; Ryu, Kook Hui; Zhou, Jing; Tarkowská, Danuše; Tarkowski, Petr; Cho, Young-Hee; Yoo, Sang-Dong; Kim, Eun-Sol; Lee, Ji-Young

    2015-03-01

    Plant growth depends on stem cell niches in meristems. In the root apical meristem, the quiescent center (QC) cells form a niche together with the surrounding stem cells. Stem cells produce daughter cells that are displaced into a transit-amplifying (TA) domain of the root meristem. TA cells divide several times to provide cells for growth. SHORTROOT (SHR) and SCARECROW (SCR) are key regulators of the stem cell niche. Cytokinin controls TA cell activities in a dose-dependent manner. Although the regulatory programs in each compartment of the root meristem have been identified, it is still unclear how they coordinate one another. Here, we investigate how PHABULOSA (PHB), under the posttranscriptional control of SHR and SCR, regulates TA cell activities. The root meristem and growth defects in shr or scr mutants were significantly recovered in the shr phb or scr phb double mutant, respectively. This rescue in root growth occurs in the absence of a QC. Conversely, when the modified PHB, which is highly resistant to microRNA, was expressed throughout the stele of the wild-type root meristem, root growth became very similar to that observed in the shr; however, the identity of the QC was unaffected. Interestingly, a moderate increase in PHB resulted in a root meristem phenotype similar to that observed following the application of high levels of cytokinin. Our protoplast assay and transgenic approach using ARR10 suggest that the depletion of TA cells by high PHB in the stele occurs via the repression of B-ARR activities. This regulatory mechanism seems to help to maintain the cytokinin homeostasis in the meristem. Taken together, our study suggests that PHB can dynamically regulate TA cell activities in a QC-independent manner, and that the SHR-PHB pathway enables a robust root growth system by coordinating the stem cell niche and TA domain.

  4. A harmonic linear dynamical system for prominent ECG feature extraction.

    Science.gov (United States)

    Thi, Ngoc Anh Nguyen; Yang, Hyung-Jeong; Kim, SunHee; Do, Luu Ngoc

    2014-01-01

    Unsupervised mining of electrocardiography (ECG) time series is a crucial task in biomedical applications. To have efficiency of the clustering results, the prominent features extracted from preprocessing analysis on multiple ECG time series need to be investigated. In this paper, a Harmonic Linear Dynamical System is applied to discover vital prominent features via mining the evolving hidden dynamics and correlations in ECG time series. The discovery of the comprehensible and interpretable features of the proposed feature extraction methodology effectively represents the accuracy and the reliability of clustering results. Particularly, the empirical evaluation results of the proposed method demonstrate the improved performance of clustering compared to the previous main stream feature extraction approaches for ECG time series clustering tasks. Furthermore, the experimental results on real-world datasets show scalability with linear computation time to the duration of the time series.

  5. A Harmonic Linear Dynamical System for Prominent ECG Feature Extraction

    Directory of Open Access Journals (Sweden)

    Ngoc Anh Nguyen Thi

    2014-01-01

    Full Text Available Unsupervised mining of electrocardiography (ECG time series is a crucial task in biomedical applications. To have efficiency of the clustering results, the prominent features extracted from preprocessing analysis on multiple ECG time series need to be investigated. In this paper, a Harmonic Linear Dynamical System is applied to discover vital prominent features via mining the evolving hidden dynamics and correlations in ECG time series. The discovery of the comprehensible and interpretable features of the proposed feature extraction methodology effectively represents the accuracy and the reliability of clustering results. Particularly, the empirical evaluation results of the proposed method demonstrate the improved performance of clustering compared to the previous main stream feature extraction approaches for ECG time series clustering tasks. Furthermore, the experimental results on real-world datasets show scalability with linear computation time to the duration of the time series.

  6. Stability of thermal modes in cool prominence plasmas

    CERN Document Server

    Soler, Roberto; Parenti, Susanna

    2012-01-01

    Context: Magnetohydrodynamic thermal modes may play an important role in the formation, plasma condensation, and evolution of solar prominences. Unstable thermal modes due to unbalance between radiative losses and heating can lead to rapid plasma cooling and condensation. An accurate description of the radiative loss function is therefore crucial for this process. Aims: We study the stability of thermal modes in unbounded and uniform plasmas with properties akin to those in solar prominences. Effects due to partial ionization are taken into account. Three different parametrizations of the radiative loss function are used. Methods: By means of a normal mode analysis, we investigate linear nonadiabatic perturbations superimposed on the equilibrium state. We find an approximate instability criterion for thermal modes, while the exact linear growth rate is obtained by numerically solving the general dispersion relation. The stability of thermal disturbances is compared for the three different loss functions consi...

  7. Toward detailed prominence seismology - II. Charting the continuous magnetohydrodynamic spectrum

    CERN Document Server

    Blokland, J W S

    2011-01-01

    Starting from accurate MHD flux rope equilibria containing prominence condensations, we initiate a systematic survey of their linear eigenoscillations. To quantify the full spectrum of linear MHD eigenmodes, we require knowledge of all flux-surface localized modes, charting out the continuous parts of the MHD spectrum. We combine analytical and numerical findings for the continuous spectrum for realistic prominence configurations. The equations governing all eigenmodes for translationally symmetric, gravitating equilibria containing an axial shear flow, are analyzed, along with their flux-surface localized limit. The analysis is valid for general 2.5D equilibria, where either density, entropy, or temperature vary from one flux surface to another. We analyze the mode couplings caused by the poloidal variation in the flux rope equilibria, by performing a small gravity parameter expansion. We contrast the analytical results with continuous spectra obtained numerically. For equilibria where the density is a flux ...

  8. Prominent Determinants of Consumer-Based Brand Equity

    OpenAIRE

    Elisa Battistoni; Andrea Fronzetti Colladon; Giulia Mercorelli

    2013-01-01

    In this paper we investigate the most prominent drivers of brand equity, from a consumerbased point of view. We present a new approach for measuring brand equity, which can be applied regardless of the brand sector and is based on the Analytic Hierarchy Process. This approach has the main advantage of allowing for comparisons to be made between non‐directly measurable elements and also has the advantage of enabling the ranking of intangible criteria, such as consumers’ feelings or purchase in...

  9. 77 FR 3779 - Guidance for Industry on Product Name Placement, Size, and Prominence in Advertising and...

    Science.gov (United States)

    2012-01-25

    ... Prominence in Advertising and Promotional Labeling; Availability AGENCY: Food and Drug Administration, HHS... guidance document entitled ``Product Name Placement, Size, and Prominence in Advertising and Promotional..., size, prominence, and frequency in promotional labeling and advertising for prescription human...

  10. VLT/X-SHOOTER NEAR-INFRARED SPECTROSCOPY AND HST IMAGING OF GRAVITATIONALLY LENSED z ∼ 2 COMPACT QUIESCENT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Geier, S.; Man, A. W. S.; Krühler, T.; Toft, S.; Fynbo, J. P. U. [Dark Cosmology Centre, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Richard, J. [Centre de Recherche Astronomique de Lyon, Université Lyon 1, 9 Avenue Charles Andre, F-69230 Saint Genis Laval (France); Marchesini, D., E-mail: sgeier@astro.ku.dk [Department of Physics and Astronomy, Tufts University, Medford, MA 06520 (United States)

    2013-11-10

    Quiescent massive galaxies at z ∼ 2 are thought to be the progenitors of present-day massive ellipticals. Observations revealed them to be extraordinarily compact. Until now, the determination of stellar ages, star formation rates, and dust properties via spectroscopic measurements has been feasible only for the most luminous and massive specimens (∼3 × M*). Here we present a spectroscopic study of two near-infrared-selected galaxies that are close to the characteristic stellar mass M* (∼0.9 × M* and ∼1.3 × M*) and whose observed brightness has been boosted by the gravitational lensing effect. We measure the redshifts of the two galaxies to be z = 1.71 ± 0.02 and z = 2.15 ± 0.01. By fitting stellar population synthesis models to their spectrophotometric spectral energy distributions we determine their ages to be 2.4{sup +0.8}{sub -0.6} Gyr and 1.7 ± 0.3 Gyr, respectively, which implies that the two galaxies have higher mass-to-light ratios than most quiescent z ∼ 2 galaxies in other studies. We find no direct evidence for active star formation or active galactic nucleus activity in either of the two galaxies, based on the non-detection of emission lines. Based on the derived redshifts and stellar ages we estimate the formation redshifts to be z=4.3{sup +3.4}{sub -1.2} and z=4.3{sup +1.0}{sub -0.6}, respectively. We use the increased spatial resolution due to the gravitational lensing to derive constraints on the morphology. Fitting Sérsic profiles to the de-lensed images of the two galaxies confirms their compactness, with one of them being spheroid-like and the other providing the first confirmation of a passive lenticular galaxy at a spectroscopically derived redshift of z ∼ 2.

  11. The quiescent intracluster medium in the core of the Perseus cluster

    Science.gov (United States)

    Hitomi Collaboration; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Anabuki, Naohisa; Angelini, Lorella; Arnaud, Keith; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall; Blandford, Roger; Brenneman, Laura; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward; Chernyakova, Maria; Chiao, Meng; Coppi, Paolo; Costantini, Elisa; de Plaa, Jelle; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko; Hornschemeier, Ann; Hoshino, Akio; Hughes, John; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishibashi, Kazunori; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Itoh, Masayuki; Iyomoto, Naoko; Kaastra, Jelle; Kallman, Timothy; Kamae, Tuneyoshi; Kara, Erin; Kataoka, Jun; Katsuda, Satoru; Katsuta, Junichiro; Kawaharada, Madoka; Kawai, Nobuyuki; Kelley, Richard; Khangulyan, Dmitry; Kilbourne, Caroline; King, Ashley; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Shu; Koyama, Katsuji; Kretschmar, Peter; Krimm, Hans; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lebrun, François; Lee, Shiu-Hang; Leutenegger, Maurice; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Grzegorz; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian; Mehdipour, Missagh; Miller, Eric; Miller, Jon; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Moseley, Harvey; Mukai, Koji; Murakami, Hiroshi; Murakami, Toshio; Mushotzky, Richard; Nagino, Ryo; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakano, Toshio; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Masayoshi; Noda, Hirofumi; Nomachi, Masaharu; O'Dell, Steve; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stephane; Parmar, Arvind; Petre, Robert; Pinto, Ciro; Pohl, Martin; Porter, F. Scott; Pottschmidt, Katja; Ramsey, Brian; Reynolds, Christopher; Russell, Helen; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sameshima, Hiroaki; Sato, Goro; Sato, Kosuke; Sato, Rie; Sawada, Makoto; Schartel, Norbert; Serlemitsos, Peter; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall; Soong, Yang; Stawarz, Lukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'Ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Keisuke; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki; Tashiro, Makoto; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Ueno, Shiro; Uno, Shin'Ichiro; Urry, Meg; Ursino, Eugenio; de Vries, Cor; Watanabe, Shin; Werner, Norbert; Wik, Daniel; Wilkins, Dan; Williams, Brian; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Yoshida, Atsumasa; Yuasa, Takayuki; Zhuravleva, Irina; Zoghbi, Abderahmen

    2016-07-01

    Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the cluster, is lacking. Such knowledge would enable insights into the injection of mechanical energy by the central supermassive black hole and the use of hydrostatic equilibrium for determining cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50-million-kelvin diffuse hot plasma filling its gravitational potential well. The active galactic nucleus of the central galaxy NGC 1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These bubbles probably induce motions in the intracluster medium and heat the inner gas, preventing runaway radiative cooling—a process known as active galactic nucleus feedback. Here we report X-ray observations of the core of the Perseus cluster, which reveal a remarkably quiescent atmosphere in which the gas has a line-of-sight velocity dispersion of 164 ± 10 kilometres per second in the region 30-60 kiloparsecs from the central nucleus. A gradient in the line-of-sight velocity of 150 ± 70 kilometres per second is found across the 60-kiloparsec image of the cluster core. Turbulent pressure support in the gas is four per cent of the thermodynamic pressure, with large-scale shear at most doubling this estimate. We infer that a total cluster mass determined from hydrostatic equilibrium in a central region would require little correction for turbulent pressure.

  12. The quiescent intracluster medium in the core of the Perseus cluster

    Energy Technology Data Exchange (ETDEWEB)

    Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Anabuki, Naohisa; Angelini, Lorella; Arnaud, Keith; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall; Blandford, Roger; Brenneman, Laura; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward; Chernyakova, Maria; Chiao, Meng; Coppi, Paolo; Costantini, Elisa; de Plaa, Jelle; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko; Hornschemeier, Ann; Hoshino, Akio; Hughes, John; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishibashi, Kazunori; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Itoh, Masayuki; Iyomoto, Naoko; Kaastra, Jelle; Kallman, Timothy; Kamae, Tuneyoshi; Kara, Erin; Kataoka, Jun; Katsuda, Satoru; Katsuta, Junichiro; Kawaharada, Madoka; Kawai, Nobuyuki; Kelley, Richard; Khangulyan, Dmitry; Kilbourne, Caroline; King, Ashley; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Shu; Koyama, Katsuji; Kretschmar, Peter; Krimm, Hans; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lebrun, François; Lee, Shiu-Hang; Leutenegger, Maurice; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Grzegorz; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian; Mehdipour, Missagh; Miller, Eric; Miller, Jon; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Moseley, Harvey; Mukai, Koji; Murakami, Hiroshi; Murakami, Toshio; Mushotzky, Richard; Nagino, Ryo; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakano, Toshio; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Masayoshi; Noda, Hirofumi; Nomachi, Masaharu; O’Dell, Steve; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stephane; Parmar, Arvind; Petre, Robert; Pinto, Ciro; Pohl, Martin; Porter, F. Scott; Pottschmidt, Katja; Ramsey, Brian; Reynolds, Christopher; Russell, Helen; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sameshima, Hiroaki; Sato, Goro; Sato, Kosuke; Sato, Rie; Sawada, Makoto; Schartel, Norbert; Serlemitsos, Peter; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall; Soong, Yang; Stawarz, Lukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin’ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Keisuke; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki; Tashiro, Makoto; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Ueno, Shiro; Uno, Shin’ichiro; Urry, Meg; Ursino, Eugenio; de Vries, Cor; Watanabe, Shin; Werner, Norbert; Wik, Daniel; Wilkins, Dan; Williams, Brian; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Yoshida, Atsumasa; Yuasa, Takayuki; Zhuravleva, Irina; Zoghbi, Abderahmen

    2016-07-06

    Clusters of galaxies are the most massive gravitationally bound objects in the Universe and are still forming. They are thus important probes1 of cosmological parameters and many astrophysical processes. However, knowledge of the dynamics of the pervasive hot gas, the mass of which is much larger than the combined mass of all the stars in the cluster, is lacking. Such knowledge would enable insights into the injection of mechanical energy by the central supermassive black hole and the use of hydrostatic equilibrium for determining cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50-million-kelvin diffuse hot plasma filling its gravitational potential well. The active galactic nucleus of the central galaxy NGC 1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These bubbles probably induce motions in the intracluster medium and heat the inner gas, preventing runaway radiative cooling—a process known as active galactic nucleus feedback2, 3, 4, 5, 6. Here we report X-ray observations of the core of the Perseus cluster, which reveal a remarkably quiescent atmosphere in which the gas has a line-of-sight velocity dispersion of 164 ± 10 kilometres per second in the region 30–60 kiloparsecs from the central nucleus. A gradient in the line-of-sight velocity of 150 ± 70 kilometres per second is found across the 60-kiloparsec image of the cluster core. Turbulent pressure support in the gas is four per cent of the thermodynamic pressure, with large-scale shear at most doubling this estimate. We infer that a total cluster mass determined from hydrostatic equilibrium in a central region would require little correction for turbulent pressure.

  13. Unique Organization of the Nuclear Envelope in the Post-natal Quiescent Neural Stem Cells

    Directory of Open Access Journals (Sweden)

    Arantxa Cebrián-Silla

    2017-07-01

    Full Text Available Neural stem cells (B1 astrocytes; NSCs in the adult ventricular-subventricular-zone (V-SVZ originate in the embryo. Surprisingly, recent work has shown that B1 cells remain largely quiescent. They are reactivated postnatally to function as primary progenitors for neurons destined for the olfactory bulb and some corpus callosum oligodendrocytes. The cellular and molecular properties of quiescent B1 cells remain unknown. Here we found that a subpopulation of B1 cells has a unique nuclear envelope invagination specialization similar to envelope-limited chromatin sheets (ELCS, reported in certain lymphocytes and some cancer cells. Using molecular markers, [3H]thymidine birth-dating, and Ara-C, we found that B1 cells with ELCS correspond to quiescent NSCs. ELCS begin forming in embryonic radial glia cells and represent a specific nuclear compartment containing particular epigenetic modifications and telomeres. These results reveal a unique nuclear compartment in quiescent NSCs, which is useful for identifying these primary progenitors and study their gene regulation.

  14. PRIMUS: Effect of Galaxy Environment on the Quiescent Fraction Evolution at z < 0.8

    CERN Document Server

    Hahn, ChangHoon; Moustakas, John; Coil, Alison L; Cool, Richard J; Eisenstein, Daniel J; Skibba, Ramin A; Wong, Kenneth C; Zhu, Guangtun

    2014-01-01

    We investigate the effects of galaxy environment on the evolution of the quiescent fraction ($f_\\mathrm{Q}$) from z =0.8 to 0.0 using spectroscopic redshifts and multi-wavelength imaging data from the PRIsm MUlti-object Survey (PRIMUS) and the Sloan Digitial Sky Survey (SDSS). Our stellar mass limited galaxy sample consists of ~14,000 PRIMUS galaxies within z = 0.2-0.8 and ~64,000 SDSS galaxies within z = 0.05-0.12. We classify the galaxies as quiescent or star-forming based on an evolving specific star formation cut, and as low or high density environments based on fixed cylindrical aperture environment measurements on a volume-limited environment defining population. For quiescent and star-forming galaxies in low or high density environments, we examine the evolution of their stellar mass function (SMF). Then using the SMFs we compute $f_\\mathrm{Q}(M_{*})$ and quantify its evolution within our redshift range. We find that the quiescent fraction is higher at higher masses and in denser environments. The quie...

  15. Ordered mesoporous silica prepared by quiescent interfacial growth method - effects of reaction chemistry

    Science.gov (United States)

    Alsyouri, Hatem M.; Abu-Daabes, Malyuba A.; Alassali, Ayah; Lin, Jerry YS

    2013-11-01

    Acidic interfacial growth can provide a number of industrially important mesoporous silica morphologies including fibers, spheres, and other rich shapes. Studying the reaction chemistry under quiescent (no mixing) conditions is important for understanding and for the production of the desired shapes. The focus of this work is to understand the effect of a number of previously untested conditions: acid type (HCl, HNO3, and H2SO4), acid content, silica precursor type (TBOS and TEOS), and surfactant type (CTAB, Tween 20, and Tween 80) on the shape and structure of products formed under quiescent two-phase interfacial configuration. Results show that the quiescent growth is typically slow due to the absence of mixing. The whole process of product formation and pore structuring becomes limited by the slow interfacial diffusion of silica source. TBOS-CTAB-HCl was the typical combination to produce fibers with high order in the interfacial region. The use of other acids (HNO3 and H2SO4), a less hydrophobic silica source (TEOS), and/or a neutral surfactant (Tweens) facilitate diffusion and homogenous supply of silica source into the bulk phase and give spheres and gyroids with low mesoporous order. The results suggest two distinct regions for silica growth (interfacial region and bulk region) in which the rate of solvent evaporation and local concentration affect the speed and dimension of growth. A combined mechanism for the interfacial bulk growth of mesoporous silica under quiescent conditions is proposed.

  16. Evidence for Widespread AGN Activity among Massive Quiescent Galaxies at z ~ 2

    CERN Document Server

    Olsen, Karen Pardos; Toft, Sune; Zirm, Andrew W

    2012-01-01

    We quantify the presence of Active Galactic nuclei (AGN) in a mass-complete (M_* >5e10 M_sun) sample of 123 star-forming and quiescent galaxies at 1.5 3e42 ergs/s). The latter fraction is similar for star-forming and quiescent galaxies, and does not depend on galaxy stellar mass, suggesting that perhaps luminous AGN are triggered by external effects such as mergers. We detect significant mean X-ray signals in stacked images for both the individually non-detected star-forming and quiescent galaxies, with spectra consistent with star formation only and/or a low luminosity AGN in both cases. Comparing star formation rates inferred from the 2-10 keV luminosities to those from rest-frame IR+UV emission, we find evidence for an X-ray excess indicative of low-luminosity AGN. Among the quiescent galaxies, the excess suggests that as many as 70-100% of these contain low- or high-luminosity AGN, while the corresponding fraction is lower among star-forming galaxies (43-65%). The ubiquitous presence of AGN in massive, q...

  17. Vortex flow formation during dielectric barrier discharge initiation in quiescent air

    NARCIS (Netherlands)

    Golub, V. V.; Saveliev, A. S.

    2010-01-01

    The structure of vortex flows generated by dielectric barrier discharge initiated in quiescent air at atmospheric pressure has been studied by the methods of particle image velocimetry and schlieren photography. The flow parameters have been measured as functions of the time past the electric discha

  18. The Lgr5 intestinal stem cell signature: robust expression of proposed quiescent '+4' cell markers

    NARCIS (Netherlands)

    Munoz, J.; Stange, D.E.; Schepers, A.G.; van de Wetering, M.; Koo, B.K.; Itzkovitz, S.; Volckmann, R.; Kung, K.S.; Koster, J.; Radulescu, S.; Myant, K.; Versteeg, R.; Sansom, O.J.; van Es, J.H.; Barker, N.; van Oudenaarden, A.; Mohammed, S.; Heck, A.J.R.; Clevers, H.

    2012-01-01

    Two types of stem cells are currently defined in small intestinal crypts: cycling crypt base columnar (CBC) cells and quiescent '+4' cells. Here, we combine transcriptomics with proteomics to define a definitive molecular signature for Lgr5(+) CBC cells. Transcriptional profiling of FACS-sorted Lgr5

  19. Detection of abundant CO2 ice in the quiescent dark cloud medium toward Elias 16

    NARCIS (Netherlands)

    Whittet, DCB; Gerakines, PA; Tielens, AGGM; Adamson, AJ; Boogert, ACA; Chiar, JE; de Graauw, T; Ehrenfreund, P; Prusti, T; Schutte, WA; Vandenbussche, B; van Dishoeck, EF

    1998-01-01

    We report the first detection of solid carbon dioxide (CO2) in quiescent regions of a dark cloud in the solar neighborhood, a result that has important implications for models of ice formation and evolution in the interstellar medium. The K-type field star Elias 16 was previously known to display

  20. CANDELS+3D-HST: Compact SFGs at z ∼ 2-3, the progenitors of the first quiescent galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Barro, G.; Faber, S. M.; Koo, D. C.; Guo, Y. [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Pérez-González, P. G. [Universidad Complutense de Madrid, F. CC. Físicas, 28040 Madrid (Spain); Pacifici, C. [Yonsei University Observatory, Yonsei University, Seoul 120-749 (Korea, Republic of); Trump, J. R. [Pennsylvania State University, University Park, PA 16802 (United States); Wuyts, S.; Hsu, L. [Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, Giessenbachstr., D-85741 Garching (Germany); Bell, E. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Dekel, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Porter, L.; Primack, J. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (United States); Ferguson, H. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ashby, M. L. N.; Fazio, G. G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Caputi, K. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Ceverino, D. [Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Croton, D. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122 (Australia); Giavalisco, M. [Astronomy Department, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); and others

    2014-08-10

    We analyze the star-forming and structural properties of 45 massive (log(M/M{sub ☉}) >10) compact star-forming galaxies (SFGs) at 2 < z < 3 to explore whether they are progenitors of compact quiescent galaxies at z ∼ 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are heavily obscured. Nearly half (47%) host an X-ray-bright active galactic nucleus (AGN). In contrast, only about 10% of other massive galaxies at that time host AGNs. Compact SFGs have centrally concentrated light profiles and spheroidal morphologies similar to quiescent galaxies and are thus strikingly different from other SFGs, which typically are disk-like and sometimes clumpy or irregular. Most compact SFGs lie either within the star formation rate (SFR)-mass main sequence (65%) or below it (30%), on the expected evolutionary path toward quiescent galaxies. These results show conclusively that galaxies become more compact before they lose their gas and dust, quenching star formation. Using extensive HST photometry from CANDELS and grism spectroscopy from the 3D-HST survey, we model their stellar populations with either exponentially declining (τ) star formation histories (SFHs) or physically motivated SFHs drawn from semianalytic models (SAMs). SAMs predict longer formation timescales and older ages ∼2 Gyr, which are nearly twice as old as the estimates of the τ models. Both models yield good spectral energy distribution fits, indicating that the systematic uncertainty in the age due to degeneracies in the SFH is of that order of magnitude. However, SAM SFHs better match the observed slope and zero point of the SFR-mass main sequence. Contrary to expectations, some low-mass compact SFGs (log(M/M{sub ☉}) =10-10.6) have younger ages but lower specific SFRs than that of more massive galaxies, suggesting that the low-mass galaxies reach the red sequence faster. If the progenitors of compact SFGs are extended SFGs, state-of-the-art SAMs show that mergers

  1. Fundamental Plane of Black Hole Activity in the Quiescent Regime

    Science.gov (United States)

    Xie, Fu-Guo; Yuan, Feng

    2017-02-01

    A correlation among the radio luminosity ({L}{{R}}), X-ray luminosity ({L}{{X}}), and black hole (BH) mass ({M}{BH}) in active galactic nuclei (AGNs) and BH binaries is known to exist and is called the “fundamental plane” of BH activity. Yuan & Cui predict that the radio/X-ray correlation index, {ξ }{{X}}, changes from {ξ }{{X}}≈ 0.6 to {ξ }{{X}}≈ 1.2{--}1.3 when {L}{{X}}/{L}{Edd} decreases below a critical value of ∼ {10}-6. While many works favor such a change, there are also several works claiming the opposite. In this paper, we gather from the literature the largest quiescent AGN (defined as {L}{{X}}/{L}{Edd}≲ {10}-6) sample to date, consisting of 75 sources. We find that these quiescent AGNs follow a {ξ }{{X}}≈ 1.23 radio/X-ray relationship, in excellent agreement with the Yuan & Cui prediction. The reason for the discrepancy between the present result and some previous works is that their samples contain not only quiescent sources but also “normal” ones (i.e., {L}{{X}}/{L}{Edd}≳ {10}-6). In this case, the quiescent sources will mix up with those normal ones in {L}{{R}} and {L}{{X}}. The value of {ξ }{{X}} will then be between 0.6 and ∼1.3, with the exact value being determined by the sample composition, i.e., the fraction of the quiescent and normal sources. Based on this result, we propose that a more physical way to study the fundamental plane is to replace {L}{{R}} and {L}{{X}} with {L}{{R}}/{L}{Edd} and {L}{{X}}/{L}{Edd}, respectively.

  2. Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II- Numerical aspects

    CERN Document Server

    Antolin, Patrick; De Pontieu, Bart; Uitenbroek, Han; Van Doorsselaere, Tom; Yokoyama, Takaaki

    2015-01-01

    Transverse magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere and may be responsible for generating the Sun's million-degree outer atmosphere. However, direct evidence of the dissipation process and heating from these waves remains elusive. Through advanced numerical simulations combined with appropriate forward modeling of a prominence flux tube, we provide the observational signatures of transverse MHD waves in prominence plasmas. We show that these signatures are characterized by thread-like substructure, strong transverse dynamical coherence, an out-of-phase difference between plane-of-the-sky motions and LOS velocities, and enhanced line broadening and heating around most of the flux tube. A complex combination between resonant absorption and Kelvin-Helmholtz instabilities (KHI) takes place in which the KHI extracts the energy from the resonant layer and dissipates it through vortices and current sheets, which rapidly degenerate into turbulence. An inward enlargement of the boundary i...

  3. Subclavian artery stenosis caused by a prominent first rib

    Directory of Open Access Journals (Sweden)

    Isabelle Claus

    2015-04-01

    Full Text Available Thoracic outlet syndrome is a mechanical space problem in which the brachial plexus and/or subclavian vessels are compressed. Arterial compression is least common and almost always associated with a bony anomaly. We present a case of a 49-year-old woman with a prominent first rib which caused a subclavian artery stenosis. There are many options for subclavian artery repair through open surgery. In high-risk patients, minimal invasive techniques are favorable. To date, few case reports exist on an endovascular artery repair combined with open first rib resection. While long-term follow-up will be necessary, our preliminary results seem promising.

  4. Polarization of the sodium D lines in prominences

    Science.gov (United States)

    Landolfi, M.; Landi Degl'Innocenti, E.

    1985-07-01

    The expected polarization of the sodium D lines from solar prominences is computed as a function of the local magnetic field vector. To this aim, the formulation of the Hanle effect in terms of the statistical tensors developed by Landi Degl'Innocenti (1982) is employed, with minor changes connected to hyperfine structure. The sodium atoms are described in the incomplete Paschen-Back regime so that the validity of the results is not limited to "weak" magnetic fields. The polarization diagrams obtained are discussed and compared with the corresponding diagrams for the helium D3 line.

  5. Effects of vaccinia virus uracil DNA glycosylase catalytic site and deoxyuridine triphosphatase deletion mutations individually and together on replication in active and quiescent cells and pathogenesis in mice

    Directory of Open Access Journals (Sweden)

    Moss Bernard

    2008-12-01

    Full Text Available Abstract Background Low levels of uracil in DNA result from misincorporation of dUMP or cytosine deamination. Vaccinia virus (VACV, the prototype poxvirus, encodes two enzymes that can potentially reduce the amount of uracil in DNA. Deoxyuridine triphosphatase (dUTPase hydrolyzes dUTP, generating dUMP for biosynthesis of thymidine nucleotides while decreasing the availability of dUTP for misincorporation; uracil DNA glycosylase (UNG cleaves uracil N-glycosylic bonds in DNA initiating base excision repair. Studies with actively dividing cells showed that the VACV UNG protein is required for DNA replication but the UNG catalytic site is not, whereas the dUTPase gene can be deleted without impairing virus replication. Recombinant VACV with an UNG catalytic site mutation was attenuated in vivo, while a dUTPase deletion mutant was not. However, the importance of the two enzymes for replication in quiescent cells, their possible synergy and roles in virulence have not been fully assessed. Results VACV mutants lacking the gene encoding dUTPase or with catalytic site mutations in UNG and double UNG/dUTPase mutants were constructed. Replication of UNG and UNG/dUTPase mutants were slightly reduced compared to wild type or the dUTPase mutant in actively dividing cells. Viral DNA replication was reduced about one-third under these conditions. After high multiplicity infection of quiescent fibroblasts, yields of wild type and mutant viruses were decreased by 2-logs with relative differences similar to those observed in active fibroblasts. However, under low multiplicity multi-step growth conditions in quiescent fibroblasts, replication of the dUTPase/UNG mutant was delayed and 5-fold lower than that of either single mutant or parental virus. This difference was exacerbated by 1-day serial passages on quiescent fibroblasts, resulting in 2- to 3-logs lower titer of the double mutant compared to the parental and single mutant viruses. Each mutant was more

  6. Simulation of phase separation in quiescent and sheared liquids

    NARCIS (Netherlands)

    Thakre, Amol Kumar

    2008-01-01

    In this thesis we report on molecular dynamics simulations of phase separation of simple and complex binary liquids in sheared and non-sheared systems. The separation of milk into liquid whey and solid curd is a very common example of phase separation observed in daily life. The phenomenon finds its

  7. Perceptions of Social Responsibility of Prominent Animal Welfare Groups.

    Science.gov (United States)

    Widmar, Nicole J Olynk; Morgan, Carissa J; Croney, Candace C

    2017-08-28

    Nonhuman animal welfare is an increasingly important component of consumer expectations of corporate social responsibility (CSR). The extent to which prominent animal welfare or protection organizations may influence people's perceptions of food industry CSR may be related to an organization's perceived social responsibility. Data from an online survey of 300 U.S. residents were used to explore relationships between demographics/lifestyle choices and perceptions of prominent animal welfare organizations (using best-worst scaling methodology). Overall, the American Society for the Prevention of Cruelty to Animals was perceived to be the most socially responsible organization analyzed, followed by the Humane Society of the United States and the American Humane Association (AHA). Results suggest that the perceived social responsibility of animal protection organizations in this study was not strongly linked to personally (financially) supporting them, with 2 exceptions: the perceptions of People for the Ethical Treatment of Animals and AHA. Improved understanding of the perception of animal welfare or protection organizations can inform decision making by organizations interested in furthering animal welfare causes.

  8. Prominent spiral arms in the gaseous outer galaxy disks

    CERN Document Server

    Bertin, G

    2009-01-01

    Context: Several spiral galaxies, as beautifully exhibited by the case of NGC 6946, display a prominent large-scale spiral structure in their gaseous outer disk. Such structure is often thought to pose a dynamical puzzle, because grand-design spiral structure is traditionally interpreted as the result of density waves carried mostly in the stellar disk. Aims. Here we argue that the outer spiral arms in the cold gas outside the bright optical disk actually have a natural interpretation as the manifestation of the mechanism that excites grand-design spiral structure in the main, star-dominated body of the disk: the excitation is driven by angular momentum transport to the outer regions, through trailing density waves outside the corotation circle that can penetrate beyond the Outer Lindblad Resonance in the gaseous component of the disk. Methods: Because of conservation of the density wave action, these outgoing waves are likely to become more prominent in the outer disk and eventually reach non-linear amplitud...

  9. Quiescent Giant Molecular Cloud Cores in the Galactic Center

    Science.gov (United States)

    Lis, D. C.; Serabyn, E.; Zylka, R.; Li, Y.

    2000-01-01

    We have used the Long Wavelength Spectrometer (LWS) aboard the Infrared Space Observatory (ISO) to map the far-infrared continuum emission (45-175 micrometer) toward several massive Giant Molecular Cloud (GMC) cores located near the Galactic center. The observed far-infrared and submillimeter spectral energy distributions imply low temperatures (approx. 15 - 22 K) for the bulk of the dust in all the sources, consistent with external heating by the diffuse ISRF and suggest that these GMCs do not harbor high- mass star-formation sites, in spite of their large molecular mass. Observations of FIR atomic fine structure lines of C(sub II) and O(sub I) indicate an ISRF enhancement of approx. 10(exp 3) in the region. Through continuum radiative transfer modeling we show that this radiation field strength is in agreement with the observed FIR and submillimeter spectral energy distributions, assuming primarily external heating of the dust with only limited internal luminosity (approx. 2 x 10(exp 5) solar luminosity). Spectroscopic observations of millimeter-wave transitions of H2CO, CS, and C-34S carried out with the Caltech Submillimeter Observatory (CSO) and the Institut de Radio Astronomie Millimetrique (IRAM) 30-meter telescope indicate a gas temperature of approx. 80 K, significantly higher than the dust temperatures, and density of approx. 1 x 10(exp 5)/cc in GCM0.25 + 0.01, the brightest submillimeter source in the region. We suggest that shocks caused by cloud collisions in the turbulent interstellar medium in the Galactic center region are responsible for heating the molecular gas. This conclusion is supported by the presence of wide-spread emission from molecules such as SiO, SO, and CH3OH, which are considered good shock tracers. We also suggest that the GMCs studied here are representative of the "typical", pre-starforming cloud population in the Galactic center.

  10. Making Aggressive Prostate Cancer Quiescent by Abrogating Cholesterol Esterification

    Science.gov (United States)

    2015-10-01

    with 10% loading efficacy. Phosphate buffer (PBS) injection was used as a control. Finding: We did not observe weight loss in any of these doses. The...Public reporting burden for this collection of information is estimated to average 1 hour per response , including the time for reviewing instructions...application is to establish the viability of a new strategy of treating late stage PCa through therapeutic targeting of cholesterol metabolism in vivo

  11. Molecular Hydrogen in the Quiescent Disk of SW UMa

    Science.gov (United States)

    Raymond, John C.

    2004-01-01

    The FUSE observation has been reduced and a paper has been submitted to ApJ. The analysis has been slow because of the very noisy quality of the data, but we have derived line profile information for O VI and limits to the continuum brightness which place an interesting limit on the white dwarf temperature. The primary results are that a narrow O VI emission component seems to arise from the accretion flow onto the white dwarf itself, in agreement with cooling flow models for the X-ray spectra of low accretion rate dwarf novae. The broad component of the O VI lines is weaker than the observed C IV emission, suggesting that the UV line emission from the disk comes from photoionized plasma. A secondary result is that there is no H-2 fluorescent emission. The upper limits indicate that if molecular gas is present in the disk, it is shielded from Ly alpha photons by a layer of atomic hydrogen on the disk surface. We also derive an upper limit to the continuum level is below that observed by IUE. The limits are compatible with the lower end of the WD temperature range derived from IUE measurements, and they appear to agree with unpublished analysis of HST spectra. The grant has provided partial support for a data aide (Matt Povich) and a postdoc (Alex Lobel). It purchased a computer for M. Menou.

  12. Photospheric flows around a quiescent filament and CALAS first results .

    Science.gov (United States)

    Rondi, S.; Roudier, Th.; Molodij, G.; Bommier, V.; Malherbe, J. M.; Schmieder, B.; Meunier, N.; Rieutord, M.; Beigbeder., F.

    The horizontal photospheric flows below and around a filament are one of the components in the formation and evolution of filaments. Few studies have been done so far because this requires multiwalength time sequences with high spatial resolution. We present observations obtained in 2004 during the international JOP 178 campaign in which eleven instruments were involved, from space and ground based observatories. Several supergranulation cells are crossing the Polarity Inversion Line (PIL) allowing the transport of magnetic flux through the PIL, in particular the parasitic polarities. Before the filament eruptive phase, parasitic and normal polarities are swept by a continuous diverging horizontal flow located in the filament gap where the disappearance of the filament starts. In the future, observations at high spatial resolution on a large field-of-view would be very useful to study filaments, as they are very large structures. We also present the first images obtained with the use of our new 14 MPixel camera CALAS (CAmera for the LArge Scales of the Solar Surface) (10 arcmin× 6.7 arcmin) . These are the first large-scale and high-resolution images of the solar surface ever made.

  13. Measurements and predictions for nonevaporating sprays in a quiescent environment

    Science.gov (United States)

    Solomon, A. S. P.; Shuen, J.-S.; Faeth, G. M.; Zhang, Q.-F.

    1983-01-01

    Yule et al. (1982) have conducted a study of vaporizing sprays with the aid of laser techniques. The present investigation has the objective to supplement the measurements performed by Yule et al., by considering the limiting case of a spray in a stagnant environment. Mean and fluctuating velocities of the continuous phase are measured by means of laser Doppler anemometry (LDA) techniques, while Fraunhofer diffraction and slide impaction methods are employed to determine drop sizes. Liquid fluxes in the spray are found by making use of an isokinetic sampling probe. The obtained data are used as a basis for the evaluation of three models of the process, including a locally homogeneous flow (LHF) model, a deterministic separated flow (DSF) model, and a stochastic separated flow (SSF) model. It is found that the LHF and DSF models do not provide very satisfactory predictions for the test sprays, while the SSF model does provide reasonably good predictions of the observed structure.

  14. RUSSIAN SCIENTISTS IN JAPAN: LIFE AND WORK OF PROMINENT JAPANOLOGISTS

    Directory of Open Access Journals (Sweden)

    Ms. Darya V. Kiba

    2016-06-01

    Full Text Available This article is devoted to the life and work of prominent Japanologists Nikolai Alexandrovich Nevsky, Oleg Pletner, and Orestes Viktorovich Pletner. The author traces the contribution of scientists to the establishment of scientific relations between the USSR and Japan, examines the major life milestones of scientists in Japan. After receiving an excellent education in Russia, researchers lived in Japan for a long time. They were the founders of new scientific trends, and created a scientific heritage that has not been studied. The Pletner brothers, N. A. Nevsky can be brought into line with such scientists as N. I. Conrad, E. D. Polivanov, S. G. Eliseev, O. O. Rosenberg who were "Golden Age" orientalists of Japanese Studies in St. Petersburg. N. A. Nevsky and O. V. Pletner returned to the USSR. The author considers their fate in Soviet Russia and concludes that political history of the Soviet state in the 1930s made it impossible to strengthen and expand Japanologists School.

  15. Rayleigh-Taylor instability in partially ionized prominence plasma

    CERN Document Server

    Khomenko, E; de Vicente, A; Collados, M; Luna, M

    2013-01-01

    We study Rayleigh-Taylor instability (RTI) at the coronal-prominence boundary by means of 2.5D numerical simulations in a single-fluid MHD approach including a generalized Ohm's law. The initial configuration includes a homogeneous magnetic field forming an angle with the direction in which the plasma is perturbed. For each field inclination we compare two simulations, one for the pure MHD case, and one including the ambipolar diffusion in the Ohm's law, otherwise identical. We find that the configuration containing neutral atoms is always unstable. The growth rate of the small-scale modes in the non-linear regime is larger than in the purely MHD case.

  16. Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine

    Energy Technology Data Exchange (ETDEWEB)

    Annesley, Thomas M.; Cooks, Robert G.; Herold, David A.; Hoofnagle, Andrew N.

    2016-01-04

    Each year the journal Clinical Chemistry publishes a January special issue on a topic that is relevant to the laboratory medicine community. In January 2016 the topic is mass spectrometry, and the issue is entitled “Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine”. One popular feature in our issues is a Q&A on a topic, clearly in this case mass spectrometry. The journal is assembling a panel of 5-6 experts from various areas of mass spectrometry ranging from instrument manufacturing to practicing clinical chemists. Dick Smith is one of the scientist requested to participate in this special issue Q&A on Mass Spectrometry. The Q&A Transcript is attached

  17. Prominent strategies for environmental sustainability in the stationary energy sector

    Energy Technology Data Exchange (ETDEWEB)

    2009-03-15

    There is an obvious need for companies in the stationary energy sector to intensify their efforts to contribute to sustainable development, both at a strategy level and in order to integrate sustainable practices into their operations. The main purposes of this study are 1. to identify mechanisms that enable energy companies to strengthen the environmental sustainability of their business and contribute to a sustainable development of the stationary energy system. 2. to operationalize sustainable development within the context of energy companies and establish a framework that can be used to arrange the different activities contributing to environmental sustainability at a conceptual level. Case studies of companies with a prominent strategy for environmental sustainability were chosen as a research methodology. Studying energy companies with a strong focus on the environment was considered beneficial for capturing the essence of sustainable practices and to support relevance and richness of the data to be collected. The selection of case companies was based on an emerging framework of activities for environmental sustainability that was established from an initial study of a large number of Nordic and European energy companies. This framework has subsequently been refined and extended with the help of theoretical findings (please refer to section 2 below). The study encompasses three case companies from the Swedish stationary energy sector, all showing substantial activities in each of the areas identified in the framework. Data was collected by means of personal interviews with representatives from different departments of the firms, i.e. from the environmental department, production, development, finance and management. Interviewing employees from a broad range of functions would open up for wide discussions on sustainable firm practices and different perspectives. Document studies served as an additional data source, both for interview preparations and to

  18. AP-1 is a component of the transcriptional network regulated by GSK-3 in quiescent cells.

    Directory of Open Access Journals (Sweden)

    John W Tullai

    Full Text Available BACKGROUND: The protein kinase GSK-3 is constitutively active in quiescent cells in the absence of growth factor signaling. Previously, we identified a set of genes that required GSK-3 to maintain their repression during quiescence. Computational analysis of the upstream sequences of these genes predicted transcription factor binding sites for CREB, NFκB and AP-1. In our previous work, contributions of CREB and NFκB were examined. In the current study, the AP-1 component of the signaling network in quiescent cells was explored. METHODOLOGY/PRINCIPAL FINDINGS: Using chromatin immunoprecipitation analysis, two AP-1 family members, c-Jun and JunD, bound to predicted upstream regulatory sequences in 8 of the 12 GSK-3-regulated genes. c-Jun was phosphorylated on threonine 239 by GSK-3 in quiescent cells, consistent with previous studies demonstrating inhibition of c-Jun by GSK-3. Inhibition of GSK-3 attenuated this phosphorylation, resulting in the stabilization of c-Jun. The association of c-Jun with its target sequences was increased by growth factor stimulation as well as by direct GSK-3 inhibition. The physiological role for c-Jun was also confirmed by siRNA inhibition of gene induction. CONCLUSIONS/SIGNIFICANCE: These results indicate that inhibition of c-Jun by GSK-3 contributes to the repression of growth factor-inducible genes in quiescent cells. Together, AP-1, CREB and NFκB form an integrated transcriptional network that is largely responsible for maintaining repression of target genes downstream of GSK-3 signaling.

  19. The Ultraviolet Spectral Energy Distributions of Quiescent Black Holes and Neutron Stars

    Science.gov (United States)

    Hynes, R. I.; Robinson, E. L.

    2012-04-01

    We present Hubble Space Telescope/Advanced Camera for Surveys ultraviolet photometry of three quiescent black hole X-ray transients, X-ray Nova Muscae 1991 (GU Mus), GRO J0422+32 (V518 Per), and X-ray Nova Vel 1993 (MM Vel), and one neutron star system, Aql X-1. These are the first quiescent UV detections of these objects. All are detected at a much higher level than expected from their companion stars alone and are significant detections of the accretion flow. Three of the four UV excesses can be characterized by a blackbody of temperature 5000-13, 000 K, hotter than expected for the quiescent outer disk. A good fit could not be found for MM Vel. The source of the blackbody-like emission is most likely a heated region of the inner disk. Contrary to initial indications from spectroscopy, there does not appear to be a systematic difference in the UV luminosity or spectral shape between black holes and neutron star systems. However, combining our new data with earlier spectroscopy and published X-ray luminosities, there is a significant difference in the X-ray to UV flux ratios, with the neutron stars exhibiting L X/L UV about 10 times higher than the black hole systems. This is consistent with earlier comparisons based on estimating non-stellar optical light, but since both bandpasses we use are expected to be dominated by accretion light, we present a cleaner comparison. This suggests that the difference in X-ray luminosities cannot simply reflect differences in quiescent accretion rates and so the UV/X-ray ratio is a more robust discriminator between the black hole and neutron star populations than the comparison of X-ray luminosities alone.

  20. Evaluation of bacteriology of middle ear in early quiescent stage of chronic otitis media

    Directory of Open Access Journals (Sweden)

    Ramesh Bhandari

    2013-09-01

    Full Text Available Objectives The objectives of this study were to determine whether any organism does exist in middle ear cavity during the early quiescent stage of chronic otitis media and to isolate their types. Materials and methods Forty-seven patients of age 13 years and above with diagnosis of chronic otitis media mucosal type in early quiescent stage were included. Swab was collected from middle ear cavity for culture and sensitivity in operation theatre prior to middle ear surgery and brought to microbiology laboratory within half an hour to inoculate in Blood agar, Chocolate agar and Mac Conkey agar. The isolates were identified with the use of standard bacteriological technique. Results Aerobic bacteria were isolated from 15 cases (31.9%. Staphylococcus aureus isolated in 12(80%, Pseudomonas aeruginosa in 2(13.3% and E. coli in 1(6.7%. Conclusion Aerobic bacteria were isolated from middle ear cavity in quiescent stage of chronic otitis media in 15(32% cases. Staphylococcus aureus was the most common organism. Journal of College of Medical Sciences-Nepal, 2012, Vol-8, No-4, 22-26 DOI: http://dx.doi.org/10.3126/jcmsn.v8i4.8696

  1. Rapid Cooling of the Neutron Star in the Quiescent Super-Eddington Transient XTE J1701-462

    CERN Document Server

    Fridriksson, Joel K; Wijnands, Rudy; Mendez, Mariano; Altamirano, Diego; Cackett, Edward M; Brown, Edward F; Belloni, Tomaso M; Degenaar, Nathalie; Lewin, Walter H G

    2010-01-01

    We present Rossi X-Ray Timing Explorer and Swift observations made during the final three weeks of the 2006-2007 outburst of the super-Eddington neutron star transient XTE J1701-462, as well as Chandra and XMM-Newton observations covering the first ~800 days of the subsequent quiescent phase. The source transitioned quickly from active accretion to quiescence, with the luminosity dropping by over three orders of magnitude in ~13 days. The spectra obtained during quiescence exhibit both a thermal component, presumed to originate in emission from the neutron star surface, and a non-thermal component of uncertain origin, which has shown large and irregular variability. We interpret the observed decay of the inferred effective surface temperature of the neutron star in quiescence as the cooling of the neutron star crust after having been heated and brought out of thermal equilibrium with the core during the outburst. The interpretation of the data is complicated by an apparent temporary increase in temperature ~2...

  2. The assembly histories of quiescent galaxies since z = 0.7 from absorption line spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jieun; Conroy, Charlie [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Moustakas, John [Department of Physics and Astronomy, Siena College, Loudonville, NY 12110 (United States); Graves, Genevieve J. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Holden, Bradford P. [UCO/Lick Observatories, University of California, Santa Cruz, CA 95064 (United States); Brodwin, Mark [Department of Physics and Astronomy, University of Missouri, Kansas City, MO 64110 (United States); Brown, Michael J. I. [School of Physics, Monash University, Clayton, Vic 3800 (Australia); Van Dokkum, Pieter G. [Department of Astrophysical Sciences, Yale University, New Haven, CT 06520 (United States)

    2014-09-10

    We present results from modeling the optical spectra of a large sample of quiescent galaxies between 0.1 < z < 0.7 from the Sloan Digital Sky Survey (SDSS) and the AGN and Galaxy Evolution Survey (AGES). We examine how the stellar ages and abundance patterns of galaxies evolve over time as a function of stellar mass from 10{sup 9.6}-10{sup 11.8} M {sub ☉}. Galaxy spectra are stacked in bins of mass and redshift and modeled over a wavelength range from 4000 Å to 5500 Å. Full spectrum stellar population synthesis modeling provides estimates of the age and the abundances of the elements Fe, Mg, C, N, and Ca. We find negligible evolution in elemental abundances at fixed stellar mass over roughly 7 Gyr of cosmic time. In addition, the increase in stellar ages with time for massive galaxies is consistent with passive evolution since z = 0.7. Taken together, these results favor a scenario in which the inner ∼0.3-3 R {sub e} of massive quiescent galaxies have been passively evolving over the last half of cosmic time. Interestingly, the derived stellar ages are considerably younger than the age of the universe at all epochs, consistent with an equivalent single-burst star formation epoch of z ≲ 1.5. These young stellar population ages coupled with the existence of massive quiescent galaxies at z > 1 indicate the inhomogeneous nature of the z ≲ 0.7 quiescent population. The data also permit the addition of newly quenched galaxies at masses below ∼10{sup 10.5} M {sub ☉} at z < 0.7. Additionally, we analyze very deep Keck DEIMOS spectra of the two brightest quiescent galaxies in a cluster at z = 0.83. There is tentative evidence that these galaxies are older than their counterparts in low-density environments. In the Appendix, we demonstrate that our full spectrum modeling technique allows for accurate and reliable modeling of galaxy spectra to low S/N (∼20 Å{sup –1}) and/or low spectral resolution (R ∼ 500).

  3. RXTE Observations of Cygnus X-3

    CERN Document Server

    McCollough, M L; Zhang, S N; Harmon, B A; Paciesas, W S; Dieters, S W; Hjellming, R M; Rupen, M P; Mioduszewski, A J; Waltman, E B; Ghigo, F D; Pooley, G G; Fender, R P; Cui, W; Trushkin, S A

    1998-01-01

    In the period between May 1997 and August 1997 a series of pointed RXTE observations were made of Cyg X-3. During this period Cyg X-3 made a transition from a quiescent radio state to a flare state (including a major flare) and then returned to a quiescent radio state. Analyses of the observations are made in the context of concurrent observations in the hard X-ray (CGRO/BATSE), soft X-ray (RXTE/ASM) and the radio (Green Bank Interferometer, Ryle Telescope, and RATAN-600). Preliminary analyses of the observations are presented.

  4. An investigation into the prominence of spiral galaxy bulges

    CERN Document Server

    Graham, A W

    2001-01-01

    From a diameter-limited sample of 86 `face-on' spiral galaxies, the bulge-to-disk size and luminosity ratios, and other quantitative measurements for the prominence of the bulge are derived. The bulge and disk parameters have been estimated using a seeing convolved Sersic r^(1/n) bulge and a seeing convolved exponential disk. In general, early-type spiral galaxy bulges have Sersic values of n>1, and late-type spiral galaxy bulges have values of n 3-sigma) for the early-type spirals than the late-type spirals. This apparent contradiction with the r_e/h values can be explained with an iceberg-like scenario, in which the bulges in late-type spiral galaxies are relatively submerged in their disk. This can be achieved by varying the relative bulge/disk stellar density while maintaining the same effective bulge-to-disk size ratio. The absolute bulge magnitude - log(n) diagram is used as a diagnostic tool for comparative studies with dwarf elliptical and ordinary elliptical galaxies. At least in the B-band, these ob...

  5. Radiologic comparison of erosive polyarthritis with prominent interphalangeal involvement

    Energy Technology Data Exchange (ETDEWEB)

    Gold, R.H.; Bassett, L.W.; Theros, E.G.

    1982-05-01

    Psoriatic arthritis, Reiter's disease, and multicentric reticulohistiocytosis may manifest prominent interphalangeal joint and cutaneous involvement. All three disorders may also affect the sacroiliac joints and spine. Despite these similarities, there are basic radiologic differences enabling distinction between the three disorders. Erosive osteoarthritis must also be considered in the differential diagnosis of interphalangeal erosive arthritis. Psoriatic erosions are characteristically ill defined, often bilaterally asymmetrical, usually unaccompanied by significant osteoporosis, and frequently associated with florid proliferation of subperiosteal new bone. An unilateral polyarticular pattern, which often occurs in a single ray, is the most prevalent of several patterns of involvement. Reiter's disease exhibits many clinical and radiologic similarities to psoriatic arthritis, but in the former there tends to be selective involvement of the joints of the lower limbs and particularly the feet, with relative sparing of the hands and wrists, while in the latter the joints of the upper and lower limbs tend to be involved to an equal extent. Multicentric reticulohistiocytosis (MR). Lesions predominate in skin and synovium and result in sharply circumscribed, rapidly progressive, strikingly bilaterally symmetrical erosions spreading from joint margins to articular surfaces. Most or all of the diarthrodial joints may be affected, but interphalangeal joint predominance and early and severe atlanto-axial involvement are characteristic. Erosive osteoarthritis is characterized by interphalangeal subchondral erosions, accompanying periosteal new bone that is more subtle than that of psoriatic arthritis, and interphalangeal bony ankylosis that occurs with the same frequency as that of psoriatic arthritis.

  6. Prominent Determinants of Consumer-Based Brand Equity

    Directory of Open Access Journals (Sweden)

    Elisa Battistoni

    2013-08-01

    Full Text Available In this paper we investigate the most prominent drivers of brand equity, from a consumerbased point of view. We present a new approach for measuring brand equity, which can be applied regardless of the brand sector and is based on the Analytic Hierarchy Process. This approach has the main advantage of allowing for comparisons to be made between non‐directly measurable elements and also has the advantage of enabling the ranking of intangible criteria, such as consumers’ feelings or purchase intentions. We focus on the fashion industry, since we believe in the higher value of our approach when applied to brands which offer products with less tangible characteristics. Thanks to a case study – which involved about 250 interviewees – we succeed in finding and prioritizing the elements which can have an impact on the brand value. We also provide a global ranking for three apparel brands: Gap, H&M and Zara. The results from our model are consistent with other popular ratings and can be extremely useful for brand managers.

  7. Damping of prominence longitudinal oscillations due to mass accretion

    CERN Document Server

    Ruderman, Michael

    2016-01-01

    We study the damping of longitudinal oscillations of a prominence thread caused by the mass accretion. In this model we considered a thin curved magnetic tube filled with the plasma. The parts of the tube at the two sides of the thread are filled with hot rarefied plasma. We assume that there are flows of rarefied plasma toward the thread caused by the plasma evaporation at the magnetic tube footpoints. Our main assumption is that the hot plasma is instantaneously accommodated by the thread when it arrives at the thread, and its temperature and density become equal to those of the thread. Then we derive the system of ordinary differential equations describing the thread dynamics. We consider linear and nonlinear oscillation. The nonlinearity reduces the damping time, however this reduction is small. The damping time is inversely proportional to the accretion rate. We also obtain that the oscillation periods decrease with time. However even for the largest initial oscillation amplitude considered in our articl...

  8. Howard Russell Butler's Oil Paintings of Solar Eclipses and Prominences

    Science.gov (United States)

    Pasachoff, Jay M.; Olson, Roberta J. M.

    2014-06-01

    Howard Russell Butler (1856-1934) was invited to join the US Naval Observatory expedition to the total solar eclipse of 1918 because of his ability to paint astronomical phenomena based on quickly-made notes about spatial and color details. His giant triptych of the total eclipses of 1918, 1923, and 1925 was proposed for a never-built astronomical center at the American Museum of Natural History and wound up at their Hayden Planetarium when it was constructed in the mid-1930s. Half-size versions are installed at the Fels Planetarium at the Franklin Institute in Philadelphia and at the Firestone Library of Princeton University, whose newly conserved canvases were recently hung; the Buffalo Museum of Science has another half-size version in storage. We discuss not only the eclipse triptychs but also the series of large oil paintings he made of solar prominences (in storage at the American Museum of Natural History) and of his 1932-eclipse and other relevant works.JMP was supported for this work in part by Division III Discretionary Funds and the Brandi Fund of Williams College. His current eclipse research is supported by grants AGS-1047726 from the Solar Research Program of the Atmospheric and Geospace Sciences Division of NSF and 9327-13 from the Committee for Research and Exploration of the National Geographic Society.

  9. Ink4a/Arf(-/-) and HRAS(G12V) transform mouse mammary cells into triple-negative breast cancer containing tumorigenic CD49f(-) quiescent cells.

    Science.gov (United States)

    Kai, K; Iwamoto, T; Kobayashi, T; Arima, Y; Takamoto, Y; Ohnishi, N; Bartholomeusz, C; Horii, R; Akiyama, F; Hortobagyi, G N; Pusztai, L; Saya, H; Ueno, N T

    2014-01-23

    Intratumoral heterogeneity within individual breast tumors is a well-known phenomenon that may contribute to drug resistance. This heterogeneity is dependent on several factors, such as types of oncogenic drivers and tumor precursor cells. The purpose of our study was to engineer a mouse mammary tumor model with intratumoral heterogeneity by using defined genetic perturbations. To achieve this, we used mice with knockout (-/-) of Ink4a/Arf, a tumor suppressor locus; these mice are known to be susceptible to non-mammary tumors such as fibrosarcoma. To induce mammary tumors, we retrovirally introduced an oncogene, HRAS(G12V), into Ink4a/Arf(-/-) mammary cells in vitro, and those cells were inoculated into syngeneic mice mammary fat pads. We observed 100% tumorigenesis. The tumors formed were negative for estrogen receptor, progesterone receptor and HER2. Further, they had pathological features similar to those of human triple-negative breast cancer (TNBC) (for example, pushing borders, central necrosis). The tumors were found to be heterogeneous and included two subpopulations: CD49f(-) quiescent cells and CD49f(+)cells. Contrary to our expectation, CD49f(-) quiescent cells had high tumor-initiating potential and CD49f(+)cells had relatively low tumor-initiating potential. Gene expression analysis revealed that CD49f(-) quiescent cells overexpressed epithelial-to-mesenchymal transition-driving genes, reminiscent of tumor-initiating cells and claudin-low breast cancer. Our animal model with intratumoral heterogeneity, derived from defined genetic perturbations, allows us to test novel molecular targeted drugs in a setting that mimics the intratumoral heterogeneity of human TNBC.

  10. Quiescent Plasmas

    DEFF Research Database (Denmark)

    Jensen, Vagn Orla

    1972-01-01

    The Conference was sponsored by the European Physical Society and by the Danish Atomic Energy Commission. The latter also gave financial support. The meeting was organized by members of the Q-machine group at Risø in collaboration with an international advisory committee consisting of Dr. N. D'An...

  11. Derivation of the Spiral Motion of an Eruptive Prominence and Its Explanation

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ma Gu; Shu-Hua Zhong; Hong-Fei Liang; La-Sheng Zhan

    2006-01-01

    A 2D velocity field of the eruptive prominence (EP) of 1991 March 5 is obtained from its spectral data observed at the Yunnan Observatory and the velocity distributions along the entrance slit are derived for different observing frames. Under the assumption that matter in the EP undergoes axial, radial and possible rotational motions, we construct a theoretical velocity distribution of the EP along the entrance slit, to derive, by fitting, the angular velocity of rotation ω and the other three parameters (axial velocity v0, radial velocity vr and the angle between the EP plane and the line of sight φ). We found: an averaged angular velocity ω of 3.0 × 10-3 arc s-1 and the variation of ω with the height above the solar limb. As the EP rises, the matter within it in fact moves along a spiral path around its axis. The spiral motion density gradient between the eruptive prominence and the surrounding corona. A theoretical angular velocity w is estimated based on the DPD and basically coincides with w obtained from the optimal velocity fitting.

  12. Prominent Polarized Flares of the Blazars AO 0235+164 and PKS 1510-089

    CERN Document Server

    Sasada, Mahito; Fukazawa, Yasushi; Kawabata, Koji S; Ikejiri, Yuki; Itoh, Ryosuke; Yamanaka, Masayuki; Sakimoto, Kiyoshi; Ohsugi, Takashi; Yoshida, Michitoshi; Sato, Shuji; Kino, Masaru

    2011-01-01

    We report on multi-band photometric and polarimetric observations of the blazars AO 0235+164 and PKS 1510-089. These two blazars were active in 2008 and 2009, respectively. In these active states, prominent short flares were observed in both objects, having amplitudes of >1 mag within 10 d. The $V-J$ color became bluer when the objects were brighter in these flares. On the other hand, the color of PKS 1510-089 exhibited a trend that it became redder when it was brighter, except for its prominent flare. This redder-when-brighter trend can be explained by the strong contribution of thermal emission from an accretion disk. The polarization degree increased at the flares, and reached >25 % at the maxima. We compare these flares in AO 0235+164 and PKS 1510-089 with other short flares which were detected by our monitoring of 41 blazars. Those two flares had one of the largest variation amplitudes in both flux and polarization degree. Furthermore, we found a significant positive correlation between the amplitudes of...

  13. CANDELS: Elevated Black Hole Growth in the Progenitors of Compact Quiescent Galaxies at z ∼ 2

    Science.gov (United States)

    Kocevski, Dale D.; Barro, Guillermo; Faber, S. M.; Dekel, Avishai; Somerville, Rachel S.; Young, Joshua A.; Williams, Christina C.; McIntosh, Daniel H.; Georgakakis, Antonis; Hasinger, Guenther; Nandra, Kirpal; Civano, Francesca; Alexander, David M.; Almaini, Omar; Conselice, Christopher J.; Donley, Jennifer L.; Ferguson, Harry C.; Giavalisco, Mauro; Grogin, Norman A.; Hathi, Nimish; Hawkins, Matthew; Koekemoer, Anton M.; Koo, David C.; McGrath, Elizabeth J.; Mobasher, Bahram; Pérez González, Pablo G.; Pforr, Janine; Primack, Joel R.; Santini, Paola; Stefanon, Mauro; Trump, Jonathan R.; van der Wel, Arjen; Wuyts, Stijn; Yan, Haojing

    2017-09-01

    We examine the fraction of massive ({M}* > {10}10 {M}ȯ ) compact star-forming galaxies (cSFGs) that host an active galactic nucleus (AGN) at z∼ 2. These cSFGs are likely the direct progenitors of the compact quiescent galaxies observed at this epoch, which are the first population of passive galaxies to appear in large numbers in the early Universe. We identify cSFGs that host an AGN using a combination of Hubble WFC3 imaging and Chandra X-ray observations in four fields: the Chandra Deep Fields, the Extended Groth Strip, and the UKIDSS Ultra Deep Survey field. We find that {39.2}-3.6+3.9 % (65/166) of cSFGs at 1.4number density of cSFGs with redshift. Our results suggest that the first abundant population of massive quenched galaxies emerged directly following a phase of elevated supermassive black hole growth and further hints at a possible connection between AGN and the rapid quenching of star formation in these galaxies.

  14. Athena's Constraints on the Dense Matter Equation of State from Quiescent Low Mass X-ray Binaries

    Science.gov (United States)

    Guillot, Sebastien

    2016-07-01

    The study of neutron star quiescent low-mass X-ray binaries (qLMXBs) will address one of the science goals of the Athena X-ray observatory. The study of the soft X-ray thermal emission from the neutron star surface in qLMXBs is a crucial tool to place constrains on the dense matter equation of state and understand the interior structure of neutron stars. I will briefly review this method, its strengths and current weaknesses and limitations, as well as the current constraints on the equation of state from qLMXBs. The superior sensitivity of Athena will permit the acquisition of unprecedentedly high signal-to-noise spectra from these sources. It has been demonstrated that a single qLMXB, even with a high signal-to-noise spectrum, will not place useful constraints on the dense matter equation of state. However, a combination of qLMXB spectra has shown great promises of obtaining tight constraints on the equation of state. I will discuss the expected prospects for observations of qLMXBs and in particular, I will show that very tight constraints on the equation of state can be obtained from the observations of qLMXBs with the Athena X-ray observatory (even with a 10 % uncertainty on the flux calibration).

  15. ONE PLANE FOR ALL: MASSIVE STAR-FORMING AND QUIESCENT GALAXIES LIE ON THE SAME MASS FUNDAMENTAL PLANE AT z ∼ 0 AND z ∼ 0.7

    Energy Technology Data Exchange (ETDEWEB)

    Bezanson, Rachel [Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Franx, Marijn [Sterrewacht Leiden, Leiden University, NL-2300 RA Leiden (Netherlands); Van Dokkum, Pieter G. [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)

    2015-02-01

    Scaling relations between galaxy structures and dynamics have been studied extensively for early- and late-type galaxies, both in the local universe and at high redshifts. The abundant differences between the properties of disky and elliptical, or star-forming and quiescent, galaxies seem to be characteristic of the local universe; such clear distinctions begin to disintegrate as observations of massive galaxies probe higher redshifts. In this paper we investigate the existence of the mass fundamental plane of all massive galaxies (σ ≳ 100 km s{sup –1}). This work includes local galaxies (0.05 < z < 0.07) from the Sloan Digital Sky Survey, in addition to 31 star-forming and 72 quiescent massive galaxies at intermediate redshift (z ∼ 0.7) with absorption-line kinematics from deep Keck-DEIMOS spectra and structural parameters from Hubble Space Telescope imaging. In two-parameter scaling relations, star-forming and quiescent galaxies differ structurally and dynamically. However, we show that massive star-forming and quiescent galaxies lie on nearly the same mass fundamental plane, or the relationship between stellar mass surface density, stellar velocity dispersion, and effective radius. The scatter in this relation (measured about log σ) is low: 0.072 dex (0.055 dex intrinsic) at z ∼ 0 and 0.10 dex (0.08 dex intrinsic) at z ∼ 0.7. This 3D surface is not unique: virial relations, with or without a dependence on luminosity profile shapes, can connect galaxy structures and stellar dynamics with similar scatter. This result builds on the recent finding that mass fundamental plane has been stable for early-type galaxies since z ∼ 2. As we now find that this also holds for star-forming galaxies to z ∼ 0.7, this implies that these scaling relations of galaxies will be minimally susceptible to progenitor biases owing to the evolving stellar populations, structures, and dynamics of galaxies through cosmic time.

  16. Islet1 and its co-factor Ldb1 are expressed in quiescent cells of mouse intestinal epithelium.

    Directory of Open Access Journals (Sweden)

    Evgeny Makarev

    Full Text Available Islet1 belongs to Lim homeobox (Lhx gene family which encodes transcription factors that have been conserved in evolution. They form complexes with other transcriptional regulators, among them obligatory co-factors encoded by Ldb genes. Isl1 (Islet1, Lhx and Ldb1 genes play a crucial role in organ patterning, cell fate determination and cell differentiation in both embryonic and adult tissues. In this study we analyzed expression pattern of Isl1 and its co-factor Ldb1 in small intestine. We also studied the biological role of Ldb1 in gut endoderm. Quantitative PCR analysis revealed a relatively high level of expression of Lhx1, Isl1, Isl2, Lmx1a, Ldb1 and Ldb2 mRNAs in the gut tissue as compared to the level of less abundant detectable Lmx1b mRNA. Immunohistochemical studies demonstrated a unique pattern of Ldb1 and Islet1 proteins in the crypt compartment. Ldb1 is produced at a low level in majority of crypt cells; but, its abundant expression was demonstrated for some single cells. Islet1 is also expressed in single cells of the crypt. Double staining experiments with Ldb1 and Isl1 antibodies showed that both genes are co-expressed in certain cells of the crypt. Further analysis revealed the Ldb1-expressing cells in the gut are both of endodermal and mesodermal origin. Proliferation studies using antibodies to phospho-histone H3 and Ki-67 antigens, as well as long-term BrdU labeling, showed that cells prominently expressing Ldb1/Islet1 are quiescent but do not belong to any known terminally differentiated cell lineages. They may represent a group of stem-like cells in the crypt. Further experiments by cell lineage tracing should be performed to better characterize this cell population. Functional studies of mice with Ldb1 gene ablated in gut endoderm revealed no specific role of Ldb1 in that tissue.

  17. Isolation and Characterization of Ischemia-Derived Astrocytes (IDAs) with Ability to Transactivate Quiescent Astrocytes

    Science.gov (United States)

    Villarreal, Alejandro; Rosciszewski, Gerardo; Murta, Veronica; Cadena, Vanesa; Usach, Vanina; Dodes-Traian, Martin M.; Setton-Avruj, Patricia; Barbeito, Luis H.; Ramos, Alberto J.

    2016-01-01

    Reactive gliosis involving activation and proliferation of astrocytes and microglia, is a widespread but largely complex and graded glial response to brain injury. Astroglial population has a previously underestimated high heterogeneity with cells differing in their morphology, gene expression profile, and response to injury. Here, we identified a subset of reactive astrocytes isolated from brain focal ischemic lesions that show several atypical characteristics. Ischemia-derived astrocytes (IDAs) were isolated from early ischemic penumbra and core. IDA did not originate from myeloid precursors, but rather from pre-existing local progenitors. Isolated IDA markedly differ from primary astrocytes, as they proliferate in vitro with high cell division rate, show increased migratory ability, have reduced replicative senescence and grow in the presence of macrophages within the limits imposed by the glial scar. Remarkably, IDA produce a conditioned medium that strongly induced activation on quiescent primary astrocytes and potentiated the neuronal death triggered by oxygen-glucose deprivation. When re-implanted into normal rat brains, eGFP-IDA migrated around the injection site and induced focal reactive gliosis. Inhibition of gamma secretases or culture on quiescent primary astrocytes monolayers facilitated IDA differentiation to astrocytes. We propose that IDA represent an undifferentiated, pro-inflammatory, highly replicative and migratory astroglial subtype emerging from the ischemic microenvironment that may contribute to the expansion of reactive gliosis. Main Points: Ischemia-derived astrocytes (IDA) were isolated from brain ischemic tissue IDA show reduced replicative senescence, increased cell division and spontaneous migration IDA potentiate death of oxygen-glucose deprived cortical neurons IDA propagate reactive gliosis on quiescent astrocytes in vitro and in vivo Inhibition of gamma secretases facilitates IDA differentiation to astrocytes PMID:27313509

  18. Distinct transcriptional networks in quiescent myoblasts: a role for Wnt signaling in reversible vs. irreversible arrest.

    Science.gov (United States)

    Subramaniam, Sindhu; Sreenivas, Prethish; Cheedipudi, Sirisha; Reddy, Vatrapu Rami; Shashidhara, Lingadahalli Subrahmanya; Chilukoti, Ravi Kumar; Mylavarapu, Madhavi; Dhawan, Jyotsna

    2014-01-01

    Most cells in adult mammals are non-dividing: differentiated cells exit the cell cycle permanently, but stem cells exist in a state of reversible arrest called quiescence. In damaged skeletal muscle, quiescent satellite stem cells re-enter the cell cycle, proliferate and subsequently execute divergent programs to regenerate both post-mitotic myofibers and quiescent stem cells. The molecular basis for these alternative programs of arrest is poorly understood. In this study, we used an established myogenic culture model (C2C12 myoblasts) to generate cells in alternative states of arrest and investigate their global transcriptional profiles. Using cDNA microarrays, we compared G0 myoblasts with post-mitotic myotubes. Our findings define the transcriptional program of quiescent myoblasts in culture and establish that distinct gene expression profiles, especially of tumour suppressor genes and inhibitors of differentiation characterize reversible arrest, distinguishing this state from irreversibly arrested myotubes. We also reveal the existence of a tissue-specific quiescence program by comparing G0 C2C12 myoblasts to isogenic G0 fibroblasts (10T1/2). Intriguingly, in myoblasts but not fibroblasts, quiescence is associated with a signature of Wnt pathway genes. We provide evidence that different levels of signaling via the canonical Wnt pathway characterize distinct cellular states (proliferation vs. quiescence vs. differentiation). Moderate induction of Wnt signaling in quiescence is associated with critical properties such as clonogenic self-renewal. Exogenous Wnt treatment subverts the quiescence program and negatively affects clonogenicity. Finally, we identify two new quiescence-induced regulators of canonical Wnt signaling, Rgs2 and Dkk3, whose induction in G0 is required for clonogenic self-renewal. These results support the concept that active signal-mediated regulation of quiescence contributes to stem cell properties, and have implications for pathological

  19. Transport of gaseous pollutants around a human body in quiescent indoor environment

    DEFF Research Database (Denmark)

    Licina, Dusan; Melikov, Arsen Krikor; Mioduszewski, Pawel

    2014-01-01

    (CBL) to transport the pollution in quiescent indoor environment. A human body is resembled by a thermal manikin with a body shape and surface temperature distribution of a real person. The objective of the study is to examine the impact of the pollutant location around the human body on the pollution...... concentration levels in the breathing zone. The results show that the location of the pollution source has a considerable influence of the breathing zone concentrations. This is contributed to the human CBL, as it pulls the pollution emitted close to the human body and transports it to the breathing zone...... the human body should be recognized in ventilation design practice....

  20. Suppressing star formation in quiescent galaxies with supermassive black hole winds

    OpenAIRE

    Cheung, Edmond; Bundy, Kevin; Cappellari, Michele; Peirani, Sébastien; Rujopakarn, Wiphu; Westfall, Kyle; Yan, Renbin; Bershady, Matthew; Greene, Jenny E.; Heckman, Timothy M.; Drory, Niv; Law, David R.; Masters, Karen L.; Thomas, Daniel; Wake, David A.

    2016-01-01

    This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Nature Publishing Group. Quiescent galaxies with little or no ongoing star formation dominate the galaxy population above M∗ ∼ 2×10^10 M , where their numbers have increased by a factor of ∼ 25 since z ∼ 2. Once star formation is initially shut down, perhaps during the quasar phase of rapid accretion onto a supermassive black hole, an unknown mechanism must remove or heat subseq...

  1. STABILITY AND MIXING CHARACTER FOR BUOYANT JETS IN QUIESCENT SHALLOW WATER

    Institute of Scientific and Technical Information of China (English)

    ZENG Yu-hong

    2005-01-01

    The near field stability and mixing characteristics of buoyant jets produced by thermal diffuse in quiescent shallow water are investigated numerically to predict under what combinations of discharge and ambient characteristics the near field will be stable or unstable.Analyses for different discharging types show that the discharge stability is purely dependent on the near-field behavior of the jets, or the dynamic interaction of the buoyant jet region, the surface impingement region and the internal hydraulic jump region, and is independent of the far-field geometry of the receiving water.The stability criterion is a function of the relative submerged depth, and source densimetric Froude number.

  2. Quasi-Quiescent Radio Emission from the First Radio-Emitting T Dwarf

    CERN Document Server

    Williams, Peter K G; Zauderer, B Ashley

    2013-01-01

    Radio detections of ultracool dwarfs provide insight into their magnetic fields and the dynamos that maintain them, especially at the very bottom of the main sequence, where other activity indicators dramatically weaken. Until recently, the coolest brown dwarf detected in the radio was only of spectral type L3.5, but this has changed with the Arecibo detection of rapid polarized flares from the T6.5 dwarf 2MASS J10475385+2124234. Here, we report the detection of quasi-quiescent radio emission from this source at 5.8 GHz using the Karl G. Jansky Very Large Array. The luminosity is {\

  3. Neutron Star Mass-Radius Constraints of the Quiescent Low-mass X-ray Binaries X7 and X5 in the Globular Cluster 47 Tuc

    CERN Document Server

    Bogdanov, Slavko; Özel, Feryal; Güver, Tolga

    2016-01-01

    We present Chandra ACIS-S sub-array observations of the quiescent neutron star low-mass X-ray binaries X7 and X5 in the globular cluster 47 Tuc. The large reduction in photon pile-up compared to previous deep exposures enables a substantial improvement in the spectroscopic determination of the neutron star radius and mass of these neutron stars. Modeling the thermal emission from the neutron star surface with a non-magnetized hydrogen atmosphere and accounting for numerous sources of uncertainties, we obtain for the neutron star in X7 a radius of $R=11.1^{+0.8}_{-0.7}$ km for an assumed stellar mass of $M=1.4$ M$_{\\odot}$ (68% C.L.). We argue, based on astrophysical grounds, that the presence of a He atmosphere is unlikely for this source. Due to eclipses and variable absorption, the quiescent low-mass X-ray binary X5 provides less stringent constraints, leading to a radius of $R=9.6^{+0.9}_{-1.1}$ km, assuming a hydrogen atmosphere and a mass of $M=1.4$ M$_{\\odot}$. When combined with all other existing spec...

  4. Crystallization, recrystallization, and melting lines in syndiotactic polypropylene crystallized from quiescent melt and semicrystalline state due to stress-induced localized melting and recrystallization.

    Science.gov (United States)

    Lu, Ying; Wang, Yaotao; Fu, Lianlian; Jiang, Zhiyong; Men, Yongfeng

    2014-11-13

    Crystalline lamellar thickness in syndiotactic polypropylene (sPP) during crystallization from either isothermal molten or stretching induced localized melt states and during subsequent heating was investigated by means of temperature dependent small-angle X-ray scattering techniques. Well-defined crystallization lines where the reciprocal lamellar thickness is linearly dependent on crystallization temperature were observed. Unlike in the case of polybutene-1 where stretching crystallization line was shifted to direction of much smaller lamellar thickness (Macromolecules 2013, 46, 7874), the stretching induced crystallization line for sPP deviates from its corresponding isothermal crystallization line only slightly. Such phenomenon could be attributed to the fact that both crystallization processes from quiescent melt and stress induced localized melt are mediated in a mesomorphic phase in sPP. Subsequent heating of sPP after crystallization revealed the same melting behavior in both systems for the two kinds of crystallites obtained from either quiescent melt or stretching induced localized melt. Both of them underwent melting and recrystallization when the lamellar thickness was smaller than a critical value and melting directly without changing in thickness when the lamellar thickness was larger than the critical value. The melting behavior in sPP systems can be understood by considering the chain relaxation ability within crystalline phase and also can be used as evidence that the crystallization from molten state and stress-induced crystallization passed through the intermediate phase before forming crystallites.

  5. What Are the Progenitors of Compact, Massive, Quiescent Galaxies at z=2.3? The Population of Massive Galaxies at z>3 from NMBS and CANDELS

    CERN Document Server

    Stefanon, Mauro; Rudnick, Gregory H; Brammer, Gabriel B; Whitaker, Katherine E

    2013-01-01

    [Abridged] Using public data from the NMBS and CANDELS surveys, we study the population of massive galaxies at z>3 to identify the potential progenitors of z~2 compact, massive, quiescent (CMQ) galaxies, furthering our understanding of the evolution of massive galaxies. Our work is enabled by high-resolution CANDELS images and accurate photometric redshifts, stellar masses and star formation rates (SFRs) from 37-band NMBS photometry. The total number of z>3 massive galaxies is consistent with the number of massive quiescent (MQ) galaxies at z~2, implying that the SFRs for all of these galaxies must be much lower by z~2. We discover 4 CMQ galaxies at z>3, pushing back the time for which such galaxies have been observed. However, the volume density for these galaxies is significantly less than that of galaxies at z10^(10.6)Msun, likely to become members of the CMQ galaxy population at z~2. We evolve the stellar masses and SFRs of each individual z>3 galaxy adopting 5 different star formation histories (SFHs) an...

  6. Damped large amplitude oscillations in a solar prominence and a bundle of coronal loops

    CERN Document Server

    Zhang, Quanhao; Liu, Rui; Shen, Chenglong; Zhang, Min; Gou, Tingyu; Liu, Jiajia; Liu, Kai; Zhou, Zhenjun; Wang, Shui

    2016-01-01

    We investigate the evolutions of two prominences (P1,P2) and two bundles of coronal loops (L1,L2), observed with SDO/AIA near the east solar limb on 2012 September 22. It is found that there were large-amplitude oscillations in P1 and L1, but no detectable motions in P2 and L2. These transverse oscillations were triggered by a large-scale coronal wave, originating from a large flare in a remote active region behind the solar limb. By carefully comparing the locations and heights of these oscillating and non-oscillating structures, we conclude that the propagating height of the wave is between 50 Mm and 130 Mm. The wave energy deposited in the oscillating prominence and coronal loops is at least of the order of $10^{28}$ erg. Furthermore, local magnetic field strength and Alfv\\'{e}n speeds are derived from the oscillating periods and damping time scales, which are extracted from the time series of the oscillations. It is demonstrated that oscillations can be used in not only coronal seismology, but also reveal...

  7. X-ray and UV correlation in the quiescent emission of Cen X-4, evidence of accretion and reprocessing

    CERN Document Server

    Bernardini, F; Brown, E F; D'Angelo, C; Degenaar, N; Miller, J M; Reynolds, M; Wijnands, R

    2013-01-01

    We conducted the first long-term (60 days), multiwavelength (optical, ultraviolet, and X-ray) simultaneous monitoring of Cen X-4 with daily Swift observations, with the goal of understanding variability in the low mass X-ray binary Cen X-4 during quiescence. We found Cen X-4 to be highly variable in all energy bands on timescales from days to months, with the strongest quiescent variability a factor of 22 drop in the X-ray count rate in only 4 days. The X-ray, UV and optical (V band) emission are correlated on timescales down to less than 110 s. The shape of the correlation is a power law with index gamma about 0.2-0.6. The X-ray spectrum is well fitted by a hydrogen NS atmosphere (kT=59-80 eV) and a power law (with spectral index Gamma=1.4-2.0), with the spectral shape remaining constant as the flux varies. Both components vary in tandem, with each responsible for about 50% of the total X-ray flux, implying that they are physically linked. We conclude that the X-rays are likely generated by matter accreting ...

  8. Gene Expression Differences between Enriched Normal and Chronic Myelogenous Leukemia Quiescent Stem/Progenitor Cells and Correlations with Biological Abnormalities

    Directory of Open Access Journals (Sweden)

    M. Affer

    2011-01-01

    Full Text Available In comparing gene expression of normal and CML CD34+ quiescent (G0 cell, 292 genes were downregulated and 192 genes upregulated in the CML/G0 Cells. The differentially expressed genes were grouped according to their reported functions, and correlations were sought with biological differences previously observed between the same groups. The most relevant findings include the following. (i CML G0 cells are in a more advanced stage of development and more poised to proliferate than normal G0 cells. (ii When CML G0 cells are stimulated to proliferate, they differentiate and mature more rapidly than normal counterpart. (iii Whereas normal G0 cells form only granulocyte/monocyte colonies when stimulated by cytokines, CML G0 cells form a combination of the above and erythroid clusters and colonies. (iv Prominin-1 is the gene most downregulated in CML G0 cells, and this appears to be associated with the spontaneous formation of erythroid colonies by CML progenitors without EPO.

  9. Discovery of a candidate quiescent low-mass X-ray binary in the globular cluster NGC 6553

    CERN Document Server

    Guillot, Sebastien; Brown, Edward F; Pavlov, George G; Zavlin, Vyacheslav E

    2011-01-01

    This paper reports the search for quiescent low-mass X-ray binaries (qLMXBs) in the globular cluster (GC) NGC 6553 using an XMM-Newton observation designed specifically for that purpose. The analysis leading to the spectral identification of one candidate qLMXB in the core of the cluster, based on the consistency of the spectrum with a neutron star H-atmosphere model at the distance of NGC 6553, is described in this paper. Specifically, the best-fit radius found using the three XMM European Photon Imaging Camera (EPIC) spectra is R_NS=6.3(+2.3)(-0.8) km (for M_NS=1.4 Msun) and the best-fit temperature is kTeff=136(+21)(-34) eV. Both physical parameters are in accordance with typical values of previously identified qLMXBs in GC and in the field, i.e. R_NS~5-20 km and kTeff~50-150 eV. A power-law (PL) component with a photon index Gamma=2.1(+0.5)(-0.8) is also required for the spectral fit and contributes to ~33% of the total flux of the X-ray source. A detailed analysis supports the hypothesis that the PL comp...

  10. MORPHOLOGY AND DYNAMICS OF SOLAR PROMINENCES FROM 3D MHD SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M., E-mail: jaume.terradas@uib.es [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain)

    2015-01-20

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

  11. Morphology and dynamics of solar prominences from 3D MHD simulations

    CERN Document Server

    Terradas, J; Luna, M; Oliver, R; Ballester, J L

    2014-01-01

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic (MHD) equations in three dimensions we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma$-\\beta$ is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor (MRT) instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic fie...

  12. The SPLASH survey: Quiescent galaxies are more strongly clustered but are not necessarily located in high-density environments

    CERN Document Server

    Lin, Lihwai; Laigle, C; Ilbert, O; Hsieh, Bau-Ching; Jian, Hung-Yu; Lemaux, B C; Silverman, J D; Coupon, Jean; McCracken, H J; Hasinger, G; Fevre, O Le; Scoville, N

    2015-01-01

    We use the stellar mass-selected catalog from the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) in the COSMOS field to study the environments of galaxies via galaxy density and clustering analyses up to $z \\sim 2.5$. The clustering strength of quiescent galaxies exceeds that of star-forming galaxies, implying that quiescent galaxies are preferentially located in more massive halos. When using local density measurement, we find a clear positive quiescent fraction -- density relation at $z 1.5$, the quiescent fraction depends little on the local density, even though clustering shows that quiescent galaxies are in more massive halos. We argue that at high redshift the typical halo size falls below $10^{13}$ solar mass, where intrinsically the local density measurements are so varied that they do not trace the halo mass. Our results thus suggest that in the high-redshift Universe, halo mass may be the key in quenching the star formation in galaxies, rather than the conventionally measured galaxy dens...

  13. Isolation and characterization of ischemia-derived astrocytes (IDA with ability to transactivate quiescent astrocytes

    Directory of Open Access Journals (Sweden)

    Alejandro eVillarreal

    2016-06-01

    Full Text Available Reactive gliosis involving activation and proliferation of astrocytes and microglia, is a widespread but largely complex and graded glial response to brain injury. Astroglial population has a previously underestimated high heterogeneity with cells differing in their morphology, gene expression profile and response to injury. Here, we identified a subset of reactive astrocytes isolated from brain focal ischemic lesions that show several atypical characteristics. Ischemia-derived astrocytes (IDA were isolated from early ischemic penumbra and core. IDA did not originate from myeloid precursors, but rather from pre-existing local progenitors. Isolated IDA markedly differ from primary astrocytes, as they proliferate in vitro with high cell division rate, show increased migratory ability, have reduced replicative senescence and grow in the presence of macrophages within the limits imposed by the glial scar. Remarkably, IDA produce a conditioned medium that strongly induced activation on quiescent primary astrocytes and potentiated the neuronal death triggered by oxygen-glucose deprivation (OGD. When re-implanted into normal rat brains, eGFP-IDA migrated around the injection site and induced focal reactive gliosis. Inhibition of gamma secretases or culture on quiescent primary astrocytes monolayers facilitated IDA differentiation to astrocytes. We propose that IDA represent an undifferentiated, pro-inflammatory, highly replicative and migratory astroglial subtype emerging from the ischemic microenvironment that may contribute to the expansion of reactive gliosis.

  14. Accretion and nuclear activity of quiescent supermassive black holes. II: optical study and interpretation

    CERN Document Server

    Soria, R; Fabbiano, G; Baldi, A; Elvis, M; Jerjen, H; Pellegrini, S; Siemiginowska, A; Soria, Roberto; Graham, Alister W.; Fabbiano, Giuseppina; Baldi, Alessandro; Elvis, Martin; Jerjen, Helmut; Pellegrini, Silvia; Siemiginowska, Aneta

    2006-01-01

    Our X-ray study of the nuclear activity in a new sample of six quiescent early-type galaxies, and in a larger sample from the literature, confirmed (Soria et al., Paper I) that the Bondi accretion rate of diffuse hot gas is not a good indicator of the supermassive black hole (SMBH) X-ray luminosity. Here we suggest that a more reliable estimate of the accretion rate must include the gas released by the stellar population inside the sphere of influence of the SMBH, in addition to the Bondi inflow of hot gas across that surface. We use optical surface-brightness profiles to estimate the mass-loss rate from stars in the nuclear region: we show that for our sample of galaxies it is an order of magnitude higher (~ 10^{-4} - 10^{-3} M_sun/yr) than the Bondi inflow rate of hot gas, as estimated from Chandra (Paper I). Only by taking into account both sources of fuel can we constrain the true accretion rate, the accretion efficiency, and the power budget. Radiatively efficient accretion is ruled out, for quiescent SM...

  15. The Fundamental Plane of massive quiescent galaxies out to z~2

    CERN Document Server

    van de Sande, Jesse; Franx, Marijn; Bezanson, Rachel; van Dokkum, Pieter G

    2014-01-01

    The Fundamental Plane (FP) of early-type galaxies, relating the effective radius, velocity dispersion, and surface brightness, has long been recognized as a unique tool for analyzing galaxy structure and evolution. With the discovery of distant quiescent galaxies and the introduction of high sensitivity near-infrared spectrographs, it is now possible to explore the FP out to z~2. In this Letter we study the evolution of the FP out to z~2 using kinematic measurements of massive quiescent galaxies ($M_{*}>10^{11} M_{\\odot}$). We find preliminary evidence for the existence of an FP out to z~2. The scatter of the FP, however, increases from z~0 to z~2, even when taking into account the larger measurement uncertainties at higher redshifts. We find a strong evolution of the zero point from z~2 to z~0: $\\Delta\\log_{10}M/L_g\\propto(-0.49\\pm0.03)~z$. In order to assess whether our spectroscopic sample is representative of the early-type galaxy population at all redshifts, we compare their rest-frame g-z colors with th...

  16. Transformation of quiescent adult oligodendrocyte precursor cells into malignant glioma through a multistep reactivation process.

    Science.gov (United States)

    Galvao, Rui Pedro; Kasina, Anita; McNeill, Robert S; Harbin, Jordan E; Foreman, Oded; Verhaak, Roel G W; Nishiyama, Akiko; Miller, C Ryan; Zong, Hui

    2014-10-07

    How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared with their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma. Additionally, the premalignant events taking place between initial mutation and a fully developed tumor mass are particularly poorly understood in glioma. Here we used a temporally controllable Cre transgene to delete p53 and NF1 specifically in adult OPCs and demonstrated that these cells consistently give rise to malignant gliomas. To investigate the transforming process of quiescent adult OPCs, we then tracked these cells throughout the premalignant phase, which revealed a dynamic multistep transformation, starting with rapid but transient hyperproliferative reactivation, followed by a long period of dormancy, and then final malignant transformation. Using pharmacological approaches, we discovered that mammalian target of rapamycin signaling is critical for both the initial OPC reactivation step and late-stage tumor cell proliferation and thus might be a potential target for both glioma prevention and treatment. In summary, our results firmly establish the transforming potential of adult OPCs and reveal an actionable multiphasic reactivation process that turns slowly dividing OPCs into malignant gliomas.

  17. Loss of the anaphase-promoting complex in quiescent cells causes unscheduled hepatocyte proliferation

    Science.gov (United States)

    Wirth, Karin G.; Ricci, Romeo; Giménez-Abián, Juan F.; Taghybeeglu, Shahryar; Kudo, Nobuaki R.; Jochum, Wolfram; Vasseur-Cognet, Mireille; Nasmyth, Kim

    2004-01-01

    The anaphase-promoting complex or cyclosome (APC/C) is an ubiquitin protein ligase that together with Cdc20 and Cdh1 targets mitotic proteins for degradation by the proteosome. APC–Cdc20 activity during mitosis triggers anaphase by destroying securin and cyclins. APC–Cdh1 promotes degradation of cyclins and other proteins during G1. We show that loss of APC/C during embryogenesis is early lethal before embryonic day E6.5 (E6.5). To investigate the role of APC/C in quiescent cells, we conditionally inactivated the subunit Apc2 in mice. Deletion of Apc2 in quiescent hepatocytes caused re-entry into the cell cycle and arrest in metaphase, resulting in liver failure. Re-entry into the cell cycle either occurred without any proliferative stimulus or could be easily induced. We demonstrate that the APC has an additional function to prevent hepatocytes from unscheduled re-entry into the cell cycle. PMID:14724179

  18. Limits on thermal variations in a dozen quiescent neutron stars over a decade

    CERN Document Server

    Bahramian, Arash; Degenaar, Nathalie; Chomiuk, Laura; Wijnands, Rudy; Strader, Jay; Ho, Wynn C G; Pooley, David

    2015-01-01

    In quiescent low-mass X-ray binaries (qLMXBs) containing neutron stars, the origin of the thermal X-ray component may be either release of heat from the core of the neutron star, or continuing low-level accretion. In general, heat from the core should be stable on timescales $<10^4$ years, while continuing accretion may produce variations on a range of timescales. While some quiescent neutron stars (e.g. Cen X-4, Aql X-1) have shown variations in their thermal components on a range of timescales, several others, particularly those in globular clusters with no detectable nonthermal hard X-rays (fit with a powerlaw), have shown no measurable variations. Here, we constrain the spectral variations of 12 low mass X-ray binaries in 3 globular clusters over $\\sim10$ years. We find no evidence of variations in 10 cases, with limits on temperature variations below 11% for the 7 qLMXBs without powerlaw components, and limits on variations below 20% for 3 other qLMXBs that do show non-thermal emission. However, in 2 ...

  19. The self regulating star formation of gas rich dwarf galaxies in quiescent phase

    CERN Document Server

    Kobayashi, M A R; Kobayashi, Masakazu A.R.; Kamaya, Hideyuki

    2004-01-01

    The expected episodic or intermittent star formation histories (SFHs) of gas rich dwarf irregular galaxies (dIrrs) are the longstanding puzzles to understand their whole evolutional history. Solving this puzzle, we should grasp what physical mechanism causes the quiescent phase of star formation under the very gas rich condition after the first starburst phase. We consider that this quiescent phase is kept by lack of H2, which can be important coolant to generate the next generation of stars in the low-metal environment like dIrrs. Furthermore, in dIrrs, H2 formation through gas-phase reactions may dominate the one on dust-grain surfaces because their interstellar medium (ISM) are very plentiful and the typical dust-to-gas ratio of dIrrs (D_dIrrs = 1.31 x 10^-2 D_MW, where D_MW is its value for the local ISM) is on the same order with a critical value D_cr ~ 10^-2 D_MW. We show that the lack of H2 is mainly led by H- destruction when gas-phase H2 formation dominates since H- is important intermediary of gas-p...

  20. Simultaneous transverse oscillations of a prominence and a filament and longitudinal oscillation of another filament induced by a single shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yuandeng [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Liu, Ying D. [State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China); Chen, P. F. [Key Laboratory of Modern Astronomy and Astrophysics, School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Ichimoto, Kiyoshi, E-mail: ydshen@ynao.ac.cn [Kwasan and Hida Observatories, Kyoto University, Yamashina-ku, Kyoto 607-8471 (Japan)

    2014-11-10

    We present the first stereoscopic and Doppler observations of simultaneous transverse oscillations of a prominence and a filament and longitudinal oscillation of another filament launched by a single shock wave. Using Hα Doppler observations, we derive the three-dimensional oscillation velocities at different heights along the prominence axis. The results indicate that the prominence has a larger oscillation amplitude and damping time at higher altitude, but the periods at different heights are the same (i.e., 13.5 minutes). This suggests that the prominence oscillates like a linear vertical rigid body with one end anchored on the Sun. One of the filaments shows weak transverse oscillation after the passing of the shock, which is possibly due to the low altitude of the filament and the weakening (due to reflection) of the shock wave before the interaction. Large-amplitude longitudinal oscillation is observed in the other filament after the passing of the shock wave. The velocity amplitude and period are about 26.8 km s{sup –1} and 80.3 minutes, respectively. We propose that the orientation of a filament or prominence relative to the normal vector of the incoming shock should be an important factor for launching transverse or longitudinal filament oscillations. In addition, the restoring forces of the transverse prominence are most likely due to the coupling of gravity and magnetic tension of the supporting magnetic field, while that for the longitudinal filament oscillation is probably the resultant force of gravity and magnetic pressure.

  1. Too good to be true: publication bias in two prominent studies from experimental psychology.

    Science.gov (United States)

    Francis, Gregory

    2012-04-01

    Empirical replication has long been considered the final arbiter of phenomena in science, but replication is undermined when there is evidence for publication bias. Evidence for publication bias in a set of experiments can be found when the observed number of rejections of the null hypothesis exceeds the expected number of rejections. Application of this test reveals evidence of publication bias in two prominent investigations from experimental psychology that have purported to reveal evidence of extrasensory perception and to indicate severe limitations of the scientific method. The presence of publication bias suggests that those investigations cannot be taken as proper scientific studies of such phenomena, because critical data are not available to the field. Publication bias could partly be avoided if experimental psychologists started using Bayesian data analysis techniques.

  2. The physics of thermal instability in two dimensions. [model equations of solar prominences

    Science.gov (United States)

    Sparks, L.; Van Hoven, G.

    1985-01-01

    Previous studies of a thermal (radiative) instability in a sheared magnetic field have shown that, under solar coronal conditions, cool condensations can form in a small neighborhood about the shear layer. Such results have served to model the formation of solar filaments (or prominences) observed to occur above photospheric magnetic polarity-inversion lines. A surprising conclusion of these studies is that the width of the condensation does not depend on the thermal conductivity. By examining the mass-flow patterns of two-dimensional condensations in the absence of thermal conduction, it is demonstrated that local plasma dynamics and the constraints imposed by boundary conditions are together sufficient to explain the size of the condensation width. In addition the results of a series of numerical calculations are presented which illustrate the characteristic mode structure of sheared-field condensations.

  3. Discovery of a Candidate Quiescent Low-mass X-Ray Binary in the Globular Cluster NGC 6553

    Science.gov (United States)

    Guillot, Sebastien; Rutledge, Robert E.; Brown, Edward F.; Pavlov, George G.; Zavlin, Vyacheslav E.

    2011-09-01

    This paper reports the search for quiescent low-mass X-ray binaries (qLMXBs) in the globular cluster (GC) NGC 6553 using an XMM-Newton observation designed specifically for that purpose. We spectrally identify one candidate qLMXB in the core of the cluster, based on the consistency of the spectrum with a neutron star H-atmosphere model at the distance of NGC 6553. Specifically, the best-fit radius found using the three XMM European Photon Imaging Camera spectra is {R_NS}=6.3{^{+ 2.3}_{- 0.8}}{\\,km} (for {M_NS}=1.4{\\,M_\\odot }) and the best-fit temperature is {kT_eff}=136{^{+ 21}_{- 34}}{\\,eV}. Both physical parameters are in accordance with typical values of previously identified qLMXBs in GC and in the field, i.e., {R_NS}\\sim 5-20{\\,km} and {kT_eff}\\sim 50-150 {\\,eV}. A power-law (PL) component with a photon index Γ = 2.1+0.5 - 0.8 is also required for the spectral fit and contributes ~33% of the total flux of the X-ray source. A detailed analysis supports the hypothesis that the PL component originates from nearby sources in the core, unresolved with XMM. The analysis of an archived Chandra observation provides marginal additional support to the stated hypothesis. Finally, a catalog of all the sources detected within the XMM field of view is presented here.

  4. Study of a Large Helical Eruptive Prominence Associated with Double CME on 21 April 2001

    Indian Academy of Sciences (India)

    Syed Salman Ali; Wahab Uddin; Ramesh Chandra

    2006-06-01

    Here we present a preliminary analysis of a helical eruptive prominence at the east limb of the Sun on 21 April 2001. Unusually this eruption is associated with a double CME. We have tried to study the morphology of the event, energy budget of the prominence and associated CMEs. Our analysis shows that the prominence and first CME started simultaneously from the limb and prominence carries sufficient energy to feed both the CMEs. Moreover, it is also concluded that CMEs are magnetically driven and internally powered.

  5. The relative cueing power of F0 and duration in German prominence perception

    DEFF Research Database (Denmark)

    Niebuhr, Oliver; Winkler, Jana

    2017-01-01

    Previous studies showed for German and other (West) Germanic language, including English, that perceived syllable prominence is primarily controlled by changes in duration and F0, with the latter cue being more powerful than the former. Our study is an initial approach to develop this prominence...... hierarchy further by putting numbers on the interplay of duration and F0. German listeners indirectly judged through lexical identification the relative prominence levels of two neighboring syllables. Results show that an increase in F0 of between 0.49 and 0.76 st is required to outweigh the prominence...

  6. MASS ESTIMATES OF RAPIDLY MOVING PROMINENCE MATERIAL FROM HIGH-CADENCE EUV IMAGES

    Energy Technology Data Exchange (ETDEWEB)

    Williams, David R.; Baker, Deborah [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Surrey, RH5 6NT (United Kingdom); Van Driel-Gesztelyi, Lidia, E-mail: d.r.williams@ucl.ac.uk [LESIA-Observatoire de Paris, CNRS, UPMC Univ. Paris 06, Univ. Paris-Diderot, 92195 Meudon (France)

    2013-02-20

    We present a new method for determining the column density of erupting filament material using state-of-the-art multi-wavelength imaging data. Much of the prior work on filament/prominence structure can be divided between studies that use a polychromatic approach with targeted campaign observations and those that use synoptic observations, frequently in only one or two wavelengths. The superior time resolution, sensitivity, and near-synchronicity of data from the Solar Dynamics Observatory's Advanced Imaging Assembly allow us to combine these two techniques using photoionization continuum opacity to determine the spatial distribution of hydrogen in filament material. We apply the combined techniques to SDO/AIA observations of a filament that erupted during the spectacular coronal mass ejection on 2011 June 7. The resulting 'polychromatic opacity imaging' method offers a powerful way to track partially ionized gas as it erupts through the solar atmosphere on a regular basis, without the need for coordinated observations, thereby readily offering regular, realistic mass-distribution estimates for models of these erupting structures.

  7. Galaxy stellar mass functions from ZFOURGE/CANDELS: An excess of low-mass galaxies since z = 2 and the rapid buildup of quiescent galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Tomczak, Adam R.; Tran, Kim-Vy H.; Papovich, Casey; Kawinwanichakij, Lalitwadee; Mehrtens, Nicola; Spitler, Lee R.; Tilvi, Vithal [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); Quadri, Ryan F.; Kelson, Daniel D.; McCarthy, Patrick J.; Monson, Andrew J.; Persson, S. Eric [Carnegie Observatories, Pasadena, CA 91101 (United States); Labbé, Ivo; Straatman, Caroline M. S. [Sterrewacht Leiden, Leiden University, NL-2300 RA Leiden (Netherlands); Glazebrook, Karl; Allen, Rebecca; Kacprzak, Glenn G. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Brammer, Gabriel B. [European Southern Observatory, Alonso de Córdova 3107, Casilla 19001, Vitacura, Santiago (Chile); Van Dokkum, Pieter, E-mail: tomczak@physics.tamu.edu [Department of Astronomy, Yale University, New Haven, CT 06520 (United States)

    2014-03-10

    Using observations from the FourStar Galaxy Evolution Survey (ZFOURGE), we obtain the deepest measurements to date of the galaxy stellar mass function (SMF) at 0.2 < z < 3. ZFOURGE provides well-constrained photometric redshifts made possible through deep medium-bandwidth imaging at 1-2 μm. We combine this with Hubble Space Telescope imaging from the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey, allowing for the efficient selection of both blue and red galaxies down to stellar masses of ∼10{sup 9.5} M {sub ☉} at z ∼ 2.5. The total surveyed area is 316 arcmin{sup 2} distributed over three independent fields. We supplement these data with the wider and shallower NEWFIRM Medium-Band Survey to provide stronger constraints at high masses. Several studies at z ≤ 1.5 have revealed a steepening of the slope at the low-mass end of the SMF, leading to an upturn at masses <10{sup 10} M {sub ☉} that is not well described by a standard single-Schechter function. We find evidence that this feature extends to at least z ∼ 2 and that it can be found in both the star-forming and quiescent populations individually. The characteristic mass (M*) and slope at the lowest masses (α) of a double-Schechter function fit to the SMF stay roughly constant at Log(M/M {sub ☉}) ∼ 10.65 and ∼ – 1.5, respectively. The SMF of star-forming galaxies has evolved primarily in normalization, while the change in shape is relatively minor. Our data allow us, for the first time, to observe a rapid buildup at the low-mass end of the quiescent SMF. Since z = 2.5, the total stellar mass density of quiescent galaxies (down to 10{sup 9} M {sub ☉}) has increased by a factor of ∼12, whereas the mass density of star-forming galaxies only increases by a factor of ∼2.2.

  8. Novel Slope Source Term Treatment for Preservation of Quiescent Steady States in Shallow Water Flows

    Directory of Open Access Journals (Sweden)

    Khawar Rehman

    2016-10-01

    Full Text Available This paper proposes a robust method for modeling shallow-water flows and near shore tsunami propagation, applicable for both simple and complex geometries with uneven beds. The novel aspect of the model includes the introduction of a new method for slope source terms treatment to preserve quiescent equilibrium over uneven topographies, applicable to both structured and unstructured mesh systems with equal accuracy. Our model is based on the Godunov-type finite volume numerical approximation. Second-order spatial and temporal accuracy is achieved through high resolution gradient reconstruction and the predictor-corrector method, respectively. The approximate Riemann solver of Harten, Lax, and van Leer with contact wave restoration (HLLC is used to compute fluxes. Comparisons of the model’s results with analytical, experimental, and published numerical solutions show that the proposed method is capable of accurately predicting experimental and real-time tsunami propagation/inundation, and dam-break flows over varying topographies.

  9. Force Measurements of Single and Double Barrier DBD Plasma Actuators in Quiescent Air

    Science.gov (United States)

    Hoskinson, Alan R.; Hershkowitz, Noah; Ashpis, David E.

    2008-01-01

    We have performed measurements of the force induced by both single (one electrode insulated) and double (both electrodes insulated) dielectric barrier discharge plasma actuators in quiescent air. We have shown that, for single barrier actuators, as the electrode diameter decreased below those values previously studied the induced Force increases exponentially rather than linearly. This behavior has been experimentally verified using two different measurement techniques: stagnation probe measurements of the induced flow velocity and direct measurement of the force using an electronic balance. In addition, we have shown the the induced force is independent of the material used for the exposed electrode. The same techniques have shown that the induced force of a double barrier actuator increases with decreasing narrow electrode diameter.

  10. Comparisons of Force Measurement Methods for DBD Plasma Actuators in Quiescent Air

    Science.gov (United States)

    Hoskinson, Alan R.; Hershkowitz, Noah; Ashpis, David E.

    2009-01-01

    We have performed measurements of the force induced by both single (one electrode insulated) and double (both electrodes insulated) dielectric barrier discharge plasma actuators in quiescent air. We have shown that, for single barrier actuators with cylindrical exposed electrodes, as the electrode diameter decrease the force efficiencies increase much faster than a previously reported linear trend. This behavior has been experimentally verified using two different measurement techniques: stagnation probe measurements of the induced flow velocity and direct measurement of the force using an electronic balance. Actuators with rectangular cross-section exposed electrodes do not show the same rapid increase at small thicknesses. We have also shown that the induced force is independent of the material used for the exposed electrode. The same techniques have shown that the induced force of a double barrier actuator increases with decreasing narrow electrode diameter.

  11. Search for Signs of a New Outburst in the Quiescent State of CH CYG

    Science.gov (United States)

    Kotnik-Karuza, D.; Sepic, R. J.

    Our high-resolution optical spectroscopic survey of the symbiotic star CH Cyg, extending over the quiescent period 1987 - 1989 between two outbursts, shows that the spectrum did not completely lose its symbiotic character. Moreover, signs of radiation of the hot source were present, not only as remnants from the previous outburst, but also as an indication of a new one. Some of the evidences which support this idea are following: 1. Variation of excitation and vibration temperatures of neutral metals and TiO moleculs respectively 2. Untypical microturbulent velocity dependance of the excitation potential of the lower state for Fe I 3. Double-peaked Balmer profiles of Ha and Hb with temporary disappearance of the central absorption 4. Presence of forbbiden emission lines [FeII] [ SII] [NeIII] together with OIII with complex profile and variable intensity.

  12. NIMROD modeling of quiescent H-mode: reconstruction considerations and saturation mechanism

    Science.gov (United States)

    King, J. R.; Burrell, K. H.; Garofalo, A. M.; Groebner, R. J.; Kruger, S. E.; Pankin, A. Y.; Snyder, P. B.

    2017-02-01

    The extended-MHD NIMROD code (Sovinec and King 2010 J. Comput. Phys. 229 5803) models broadband-MHD activity from a reconstruction of a quiescent H-mode shot on the DIII-D tokamak (Luxon 2002 Nucl. Fusion 42 614). Computations with the reconstructed toroidal and poloidal ion flows exhibit low-{{n}φ} perturbations ({{n}φ}≃ 1 -5) that grow and saturate into a turbulent-like MHD state. The workflow used to project the reconstructed state onto the NIMROD basis functions re-solves the Grad-Shafranov equation and extrapolates profiles to include scrape-off-layer currents. Evaluation of the transport from the turbulent-like MHD state leads to a relaxation of the density and temperature profiles.

  13. Quiescent Sox2+ Cells Drive Hierarchical Growth and Relapse in Sonic Hedgehog Subgroup Medulloblastoma

    Science.gov (United States)

    Vanner, Robert J.; Remke, Marc; Gallo, Marco; Selvadurai, Hayden J.; Coutinho, Fiona; Lee, Lilian; Kushida, Michelle; Head, Renee; Morrissy, Sorana; Zhu, Xueming; Aviv, Tzvi; Voisin, Veronique; Clarke, Ian D.; Li, Yisu; Mungall, Andrew J.; Moore, Richard A.; Ma, Yussanne; Jones, Steven J.M.; Marra, Marco A.; Malkin, David; Northcott, Paul A.; Kool, Marcel; Pfister, Stefan M.; Bader, Gary; Hochedlinger, Konrad; Korshunov, Andrey; Taylor, Michael D.; Dirks, Peter B.

    2015-01-01

    SUMMARY Functional heterogeneity within tumors presents a significant therapeutic challenge. Here we show that quiescent, therapy-resistant Sox2+ cells propagate sonic hedgehog subgroup medulloblastoma by a mechanism that mirrors a neurogenic program. Rare Sox2+ cells produce rapidly cycling doublecortin+ progenitors that, together with their postmitotic progeny expressing NeuN, comprise tumor bulk. Sox2+ cells are enriched following anti-mitotic chemotherapy and Smoothened inhibition, creating a reservoir for tumor regrowth. Lineage traces from Sox2+ cells increase following treatment, suggesting that this population is responsible for relapse. Targeting Sox2+ cells with the antineoplastic mithramycin abrogated tumor growth. Addressing functional heterogeneity and eliminating Sox2+ cells presents a promising therapeutic paradigm for treatment of sonic hedgehog subgroup medulloblastoma. PMID:24954133

  14. Winter speed-up of quiescent surge-type glaciers in Yukon, Canada

    Science.gov (United States)

    Abe, T.; Furuya, M.

    2015-06-01

    Glacier surges often initiate in winter, but the mechanism remains unclear in contrast to the well-known summer speed-up at normal glaciers. To better understand the mechanism, we used radar images to examine spatial-temporal changes in the ice velocity of surge-type glaciers near the border of Alaska and the Yukon, focusing on their quiescent phase. We found significant accelerations in the upstream region from autumn to winter, regardless of surging episodes. Moreover, the winter speed-up propagated from upstream to downstream. Given the absence of surface meltwater input in winter, we suggest the presence of water storage near the base that does not directly connect to the surface, yet can promote basal sliding through increased water pressure. Our findings have implications for the modelling of glacial hydrology in winter, which may help us better understand glacier dynamics.

  15. Cerebral magnetic resonance imaging in quiescent Crohn’s disease patients with fatigue

    Science.gov (United States)

    van Erp, Sanne; Ercan, Ece; Breedveld, Perla; Brakenhoff, Lianne; Ghariq, Eidrees; Schmid, Sophie; van Osch, Matthias; van Buchem, Mark; Emmer, Bart; van der Grond, Jeroen; Wolterbeek, Ron; Hommes, Daniel; Fidder, Herma; van der Wee, Nic; Huizinga, Tom; van der Heijde, Désirée; Middelkoop, Huub; Ronen, Itamar; van der Meulen-de Jong, Andrea

    2017-01-01

    AIM To evaluate brain involvement in quiescent Crohn’s disease (CD) patients with fatigue using quantitative magnetic resonance imaging (MRI). METHODS Multiple MRI techniques were used to assess cerebral changes in 20 quiescent CD patients with fatigue (defined with at least 6 points out of an 11-point numeric rating scale compared with 17 healthy age and gender matched controls without fatigue. Furthermore, mental status was assessed by cognitive functioning, based on the neuropsychological inventory including the different domains global cognitive functioning, memory and executive functioning and in addition mood and quality of life scores. Cognitive functioning and mood status were correlated with MRI findings in the both study groups. RESULTS Reduced glutamate + glutamine (Glx = Glu + Gln) concentrations (P = 0.02) and ratios to total creatine (P = 0.02) were found in CD patients compared with controls. Significant increased Cerebral Blood Flow (P = 0.05) was found in CD patients (53.08 ± 6.14 mL/100 g/min) compared with controls (47.60 ± 8.62 mL/100 g/min). CD patients encountered significantly more depressive symptoms (P < 0.001). Cognitive functioning scores related to memory (P = 0.007) and executive functioning (P = 0.02) were lower in CD patients and both scores showed correlation with depression and anxiety. No correlation was found subcortical volumes between CD patients and controls in the T1-weighted analysis. In addition, no correlation was found between mental status and MRI findings. CONCLUSION This work shows evidence for perfusion, neurochemical and mental differences in the brain of CD patients with fatigue compared with healthy controls. PMID:28246475

  16. Opposite Effects of Soluble Factors Secreted by Adipose Tissue on Proliferating and Quiescent Osteosarcoma Cells.

    Science.gov (United States)

    Avril, Pierre; Duteille, Franck; Ridel, Perrine; Heymann, Marie-Françoise; De Pinieux, Gonzague; Rédini, Françoise; Blanchard, Frédéric; Heymann, Dominique; Trichet, Valérie; Perrot, Pierre

    2016-03-01

    Autologous adipose tissue transfer may be performed for aesthetic needs following resection of osteosarcoma, the most frequent primary malignant tumor of bone, excluding myeloma. The safety of autologous adipose tissue transfer regarding the potential risk of cancer recurrence must be addressed. Adipose tissue injection was tested in a human osteosarcoma preclinical model induced by MNNG-HOS cells. Culture media without growth factors from fetal bovine serum were conditioned with adipose tissue samples and added to two osteosarcoma cell lines (MNNG-HOS and MG-63) that were cultured in monolayer or maintained in nonadherent spheres, favoring a proliferation or quiescent stage, respectively. Proliferation and cell cycle were analyzed. Adipose tissue injection increased local growth of osteosarcoma in mice but was not associated with aggravation of lung metastasis or osteolysis. Adipose tissue-derived soluble factors increased the in vitro proliferation of osteosarcoma cells up to 180 percent. Interleukin-6 and leptin were measured in higher concentrations in adipose tissue-conditioned medium than in osteosarcoma cell-conditioned medium, but the authors' results indicated that they were not implicated alone. Furthermore, adipose tissue-derived soluble factors did not favor a G0-to-G1 phase transition of MNNG-HOS cells in nonadherent oncospheres. This study indicates that adipose tissue-soluble factors activate osteosarcoma cell cycle from G1 to mitosis phases, but do not promote the transition from quiescent G0 to G1 phases. Autologous adipose tissue transfer may not be involved in the activation of dormant tumor cells or cancer stem cells.

  17. Identification of quiescent, stem-like cells in the distal female reproductive tract.

    Directory of Open Access Journals (Sweden)

    Yongyi Wang

    Full Text Available In fertile women, the endometrium undergoes regular cycles of tissue build-up and regression. It is likely that uterine stem cells are involved in this remarkable turn over. The main goal of our current investigations was to identify slow-cycling (quiescent endometrial stem cells by means of a pulse-chase approach to selectively earmark, prospectively isolate, and characterize label-retaining cells (LRCs. To this aim, transgenic mice expressing histone2B-GFP (H2B-GFP in a Tet-inducible fashion were administered doxycycline (pulse which was thereafter withdrawn from the drinking water (chase. Over time, dividing cells progressively loose GFP signal whereas infrequently dividing cells retain H2B-GFP expression. We evaluated H2B-GFP retaining cells at different chase time points and identified long-term (LT; >12 weeks LRCs. The LT-LRCs are negative for estrogen receptor-α and express low levels of progesterone receptors. LRCs sorted by FACS are able to form spheroids capable of self-renewal and differentiation. Upon serum stimulation spheroid cells are induced to differentiate and form glandular structures which express markers of mature műllerian epithelial cells. Overall, the results indicate that quiescent cells located in the distal oviduct have stem-like properties and can differentiate into distinct cell lineages specific of endometrium, proximal and distal oviduct. Future lineage-tracing studies will elucidate the role played by these cells in homeostasis, tissue injury and cancer of the female reproductive tract in the mouse and eventually in man.

  18. Prominent Intrapulmonary Bronchopulmonary Anastomoses and Abnormal Lung Development in Infants and Children with Down Syndrome.

    Science.gov (United States)

    Bush, Douglas; Abman, Steven H; Galambos, Csaba

    2017-01-01

    To determine the frequency of histologic features of impaired lung vascular and alveolar development and to identify the presence of intrapulmonary bronchopulmonary anastomoses (IBA) in infants and children who died with Down syndrome. A retrospective review of autopsy reports and lung histology from 13 children with Down syndrome (ages: 0-8 years) was performed. Histologic features of abnormal lung development were identified and semiquantified, including the presence of IBA. Three-dimensional reconstructions of IBA were also performed. Comparisons were made with 4 age-matched patients without Down syndrome with congenital heart defects who underwent autopsies during this time period. Of the 13 subjects with Down syndrome, 69% died from cardiac events, 77% had a congenital heart defect, and 46% had a clinical diagnosis of pulmonary hypertension. Lung histology from all subjects with Down syndrome demonstrated alveolar simplification, and 92% had signs of persistence of a double capillary network in the distal lung. The lungs from the subjects with Down syndrome frequently had features of pulmonary arterial hypertensive remodeling (85%), and prominent bronchial vessels and IBA were observed in all subjects with Down syndrome. These features were more frequent in subjects with Down syndrome compared with control subjects. Children with Down syndrome who died of cardiopulmonary diseases often have histologic evidence of impaired lung alveolar and vascular development, including the presence of prominent IBA and pulmonary hypertension. We speculate that children with Down syndrome are at risk for reduced lung surface area and recruitment of IBA, which may worsen gas exchange in subjects with Down syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. In and out star formation in z 1.5 quiescent galaxies from rest-frame UV spectroscopy and the far-infrared

    Science.gov (United States)

    Gobat, R.; Daddi, E.; Strazzullo, V.; Garilli, B.; Mignoli, M.; Ma, Z.; Jin, S.; Maraston, C.; Magdis, G.; Béthermin, M.; Cappellari, M.; Carollo, M.; Cimatti, A.; Feruglio, C.; Moresco, M.; Onodera, M.; Pozzetti, L.; Renzini, A.; Sargent, M.; Valentino, F.; Zanella, A.

    2017-03-01

    We present a sample of 34 spectroscopically confirmed BzK-selected 1011M⊙ quiescent galaxies (pBzK) in the COSMOS field. The targets were initially observed with VIMOS on the VLT to facilitate the calibration of the photometric redshifts of massive galaxies at z ≳ 1.5. Here we describe the reduction and analysis of the data, and the spectrophotometric properties of these pBzK galaxies. In particular, using a spatially resolved median 2D spectrum, we find that the fraction of stellar populations with ages http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A95

  20. Intraosseous Ameloblastoma with a Prominent Extraosseous Component: Pitfalls in Diagnosis

    Science.gov (United States)

    Mishima, Kenji; Yamada, Hiroyuki; Kikuchi, Kentaro; Saito, Ichiro; Kusama, Kaoru

    2010-01-01

    For many years, gingival tumors of what appear to be peripherally located intraosseous ameloblastoma (IA) arising from the alveolar bone surface have often been confused with peripheral ameloblastoma (PA) causing resorption of the underlying bone. We analyzed a series of five cases of ameloblastoma that demonstrated a combined PA and IA architecture. The tumor commonly involved the anterior-premolar area, mostly in the maxilla and mainly in middle-aged men. The clinical presentation was an exophytic gingival mass inferior to which was a small bone defect. The predominant extraosseous component showed a papillary gross surface, reflecting the histologic proof of fusion between the submucosal tumor and the surface epithelium. In addition to the PA-like growth pattern, common to all was the presence of neoplastic destruction of the alveolar process, corresponding to an associated radiolucent lesion. This restrained component was acceptable as IA. In two cases, recurrence was observed deep in the alveolar bone with no involvement of the gingiva. These tumors appear to be IA that arose from the marginal alveolar bone and grew preferentially in the gingiva, forming a PA-like appearance. From diagnostic, therapeutic and prognostic points of view, this type of IA should not be confused with PA. PMID:20549402

  1. The Quiescent X-Ray Properties of the Accreting Millisecond X-Ray Pulsar and Eclipsing binary Swift J1749.4-2807

    Science.gov (United States)

    Degenaar, N.; Patruno, A.; Wijnands, R.

    2012-09-01

    Swift J1749.4-2807 is a transient neutron star low-mass X-ray binary that contains an accreting millisecond X-ray pulsar spinning at 518 Hz. It is the first of its kind that displays X-ray eclipses, which holds significant promise to precisely constrain the mass of the neutron star. We report on a ~= 105 ks long XMM-Newton observation performed when Swift J1749.4-2807 was in quiescence. We detect the source at a 0.5-10 keV luminosity of sime1 × 1033(D/6.7 kpc)2 erg s-1. The X-ray light curve displays three eclipses that are consistent in orbital phase and duration with the ephemeris derived during outburst. Unlike most quiescent neutron stars, the X-ray spectrum can be adequately described with a simple power law, while a pure-hydrogen atmosphere model does not fit the data. We place an upper limit on the 0.01-100 keV thermal luminosity of the cooling neutron star of <~ 2 × 1033 erg s-1 and constrain its temperature to be <~ 0.1 keV (for an observer at infinity). Timing analysis does not reveal evidence for X-ray pulsations near the known spin frequency of the neutron star or its first overtone with a fractional rms of <~ 34% and <~ 28%, respectively. We discuss the implications of our findings for dynamical mass measurements, the thermal state of the neutron star, and the origin of the quiescent X-ray emission.

  2. First Detection of Prominence Material Embedded within a 2 × 106 K CME Front Streaming away at 100-1500 km s-1 in the Solar Corona

    Science.gov (United States)

    Ding, Adalbert; Habbal, Shadia Rifai

    2017-06-01

    Coronal mass ejections (CMEs) are the largest and most dynamic explosions detected in the million degree solar corona, with speeds reaching up to 3000 km s-1 at Earth’s orbit. Triggered by the eruption of prominences, in most cases, one of the outstanding questions pertaining to the dynamic CME-prominence system is the fate of the cool {10}4{--}{10}5 {{K}} ejected filaments. We present spectroscopic observations acquired during the 2015 March 20 total solar eclipse, which captured a plethora of redshifted plasmoids from Fe xiv emission at 2× {10}6 {{K}}. Approximately 10% of these plasmoids enshrouded the same neutral and singly ionized plasma below 2× {10}5 {{K}}, observed in prominences anchored at the Sun at that time. This discovery was enabled by the novel design of a dual-channel spectrometer and the exceptionally clear sky conditions on the island of Svalbard during totality. The Doppler redshifts corresponded to speeds ranging from under 100 to over 1500 km s-1. These are the first comprehensive spectroscopic observations to unambiguously detect a 2× {10}6 {{K}} filamentary CME front with inclusions of cool prominence material. The CME front covered a projected area of 2.5× 1.5 {R}{{s}}2 starting from the solar surface. These observations imply that cool prominence inclusions within a CME front maintain their ionic composition during expansion away from the Sun.

  3. Tic Tac TOE: Effects of Predictability and Importance on Acoustic Prominence in Language Production

    Science.gov (United States)

    Watson, Duane G.; Arnold, Jennifer E.; Tanenhaus, Michael K.

    2008-01-01

    Importance and predictability each have been argued to contribute to acoustic prominence. To investigate whether these factors are independent or two aspects of the same phenomenon, naive participants played a verbal variant of Tic Tac Toe. Both importance and predictability contributed independently to the acoustic prominence of a word, but in…

  4. Transport of Substances on Different Stages of Processes Initiated by Free Fallen Drop Impact on Surface of Quiescent Water

    Science.gov (United States)

    Ilyinykh, A. Yu.

    2012-04-01

    Collision of a free fallen drop with a surface of quiescent layer of water initiates a sequence of processes including initial shock, formation of cavern and crown with a chevron edge emitted small water drops, wide central trough surrounding by a train of running surface circular capillary waves, splash, secondary cavern collapsing with a streamer discharge and gradual decal of all disturbances. Fine structure of the drop splashes and transport of substances carrying by the drop inside accepting target fluid are studied by methods of direct registering of flow images by fast video- and photo cameras. Different directions of observations were realized that are side, top and bottom view of flow patterns. Flow patterns produced by clean and coloured water, alcohol (changing the surface tension) and oil drops were investigated. Attention was concentrated on small scale processes dynamics studying which produce fast variations of water surface shapes with sharp local irregularities. Shapes and textures of craters and surrounding rim surfaces as well as coloured filaments of a drop substance inside the fluid body were registered and analyzed. Two groups of flows with relatively large scales defined by the drop diameter and very fine scales were identified. It is supposed that short living and fast changing flow components are result of strong short-acting forces impact. Their manifestations depend on surface tension on the boundaries fluid-fluid and fluid-air. Effects of surface tension gradients on the drop dye propagation pattern are also demonstrated and discussed. Experiments were performed on set-up USU "HPC IPMec RAS" under support of Ministry of Education and Science RF (Goscontract No. 16.518.11.7059).

  5. Three maize root-specific genes are not correctly expressed in regenerated caps in the absence of the quiescent center.

    Science.gov (United States)

    Ponce, G; Luján, R; Campos, M E; Reyes, A; Nieto-Sotelo, J; Feldman, L J; Cassab, G I

    2000-06-01

    The quiescent center is viewed as an architectural template in the root apical meristem of all angiosperm and gymnosperm root tips. In roots of Arabidopsis thaliana (L.) Heynh., the quiescent center inhibits differentiation of contacting initial cells and maintains the surrounding initial cells as stem cells. Here, the role of the quiescent center in the development of the maize (Zeca mays L.) root cap has been further explored. Three maize root-specific genes were identified. Two of these were exclusively expressed in the root cap and one of them encoded a GDP-mannose-4,6-dehydratase. Most likely these two genes are structural, tissue-specific markers of the cap. The third gene, a putative glycine-rich cell wall protein, was expressed in the cap and in the root epidermis and, conceivably is a positional marker of the cap. Microsurgical and molecular data indicate that the quiescent center and cap initials may regulate the positional and structural expression of these genes in the cap and thereby control root cap development.

  6. Effects of dehydroepiandrosterone on fatigue and well-being in women with quiescent systemic lupus erythematosus : a randomised controlled trial

    NARCIS (Netherlands)

    Hartkamp, A.; Geenen, R.; Godaert, G. L. R.; Bijl, M.; Bijlsma, J. W. J.; Derksen, R. H. W. M.

    Objective Dehydroepiandrosterone (DHEA) has been reported to improve fatigue and reduced well-being. Both are major problems in patients with systemic lupus erythematosus (SLE), even with quiescent disease. Low serum DHEA levels are common in SLE. The present work investigates the effects of DHEA

  7. Quiescent water-in-oil Pickering emulsions as a route toward healthier fruit juice infused chocolate confectionary

    NARCIS (Netherlands)

    Skelhon, T.S.; Grossiord, N.; Morgan, A.R.; Bon, S.A.F.

    2012-01-01

    We demonstrate a route toward the preparation of healthier fruit juice infused chocolate candy. Up to 50 wt% of the fat content in chocolate, that is cocoa butter and milk fats, is replaced with fruit juice in the form of emulsion droplets using a quiescent Pickering emulsion fabrication strategy.

  8. Quiescent water-in-oil Pickering emulsions as a route toward healthier fruit juice infused chocolate confectionary

    NARCIS (Netherlands)

    Skelhon, T.S.; Grossiord, N.; Morgan, A.R.; Bon, S.A.F.

    2012-01-01

    We demonstrate a route toward the preparation of healthier fruit juice infused chocolate candy. Up to 50 wt% of the fat content in chocolate, that is cocoa butter and milk fats, is replaced with fruit juice in the form of emulsion droplets using a quiescent Pickering emulsion fabrication strategy. F

  9. Boundary layer flow on a moving surface in otherwise quiescent pseudo-plastic non-Newtonian fluids

    Institute of Scientific and Technical Information of China (English)

    Liancun Zheng; Liu Ting; Xinxin Zhang

    2008-01-01

    A theoretical analysis for the boundary layer flow over a continuous moving surface in an otherwise quiescent pseudo-plastic non-Newtonian fluid medium was presented. The types of potential flows necessary for similar solutions to the boundary layer equations were determined and the solutions were numerically presented for different values of power law exponent.

  10. CANDELS+3D-HST: Compact SFGs at z ~ 2-3, the Progenitors of the First Quiescent Galaxies

    NARCIS (Netherlands)

    Barro, G.; Faber, S. M.; Pérez-González, P. G.; Pacifici, C.; Trump, J. R.; Koo, D. C.; Wuyts, S.; Guo, Y.; Bell, E.; Dekel, A.; Porter, L.; Primack, J.; Ferguson, H.; Ashby, M. L. N.; Caputi, K.; Ceverino, D.; Croton, D.; Fazio, G. G.; Giavalisco, M.; Hsu, L.; Kocevski, D.; Koekemoer, A.; Kurczynski, P.; Kollipara, P.; Lee, J.; McIntosh, D. H.; McGrath, E.; Moody, C.; Somerville, R.; Papovich, C.; Salvato, M.; Santini, P.; Tal, T.; van der Wel, A.; Williams, C. C.; Willner, S. P.; Zolotov, A.

    2014-01-01

    We analyze the star-forming and structural properties of 45 massive (log(M/M ⊙) >10) compact star-forming galaxies (SFGs) at 2 quiescent galaxies at z ~ 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are

  11. CANDELS+3D-HST : Compact SFGs at z~2-3, the progenitors of the first quiescent galaxies

    NARCIS (Netherlands)

    Barro, G.; Faber, S. M.; Perez-Gonzalez, P. G.; Pacifici, C.; Trump, J. R.; Koo, D. C.; Wuyts, S.; Guo, Y.; Bell, E.; Dekel, A.; Porter, L.; Primack, J.; Ferguson, H.; Ashby, M. L. N.; Caputi, K.; Ceverino, D.; Croton, D.; Fazio, G. G.; Giavalisco, M.; Hsu, L.; Kocevski, D.; Koekemoer, A.; Kurczynski, P.; Kollipara, P.; Lee, J.; McIntosh, D. H.; McGrath, E.; Moody, C.; Somerville, R.; Papovich, C.; Salvato, M.; Santini, P.; Tal, T.; van der Wel, A.; Williams, C.C.; Willner, S. P.; Zolotov, A.

    2014-01-01

    We analyze the star-forming and structural properties of 45 massive (log(M/M-circle dot) > 10) compact star-forming galaxies (SFGs) at 2 quiescent galaxies at z similar to 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that mos

  12. Quiescent water-in-oil Pickering emulsions as a route toward healthier fruit juice infused chocolate confectionary

    NARCIS (Netherlands)

    Skelhon, T.S.; Grossiord, N.; Morgan, A.R.; Bon, S.A.F.

    2012-01-01

    We demonstrate a route toward the preparation of healthier fruit juice infused chocolate candy. Up to 50 wt% of the fat content in chocolate, that is cocoa butter and milk fats, is replaced with fruit juice in the form of emulsion droplets using a quiescent Pickering emulsion fabrication strategy. F

  13. Fabrication of micro-prominences on PTFE surface using proton beam writing

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Koka, Masashi [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan); Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan)

    2013-07-01

    Polytetrafluoroethylene (PTFE) is a typical fluoropolymer and it has several desirable technological properties such as electrical insulation, solid lubrication etc. However, the conventional microstructuring methods have not been well applied to PTFE due to its chemical inertness. Some effective micromachining using synchrotron radiation or ion beam irradiation has been reported. In this study, we create micro-prominences by raising the original surface using proton beam writing (PBW) without chemical etching. A conical prominence was formed by spiral drawing from the center with a 3 MeV proton beam. The body was porous, and the bulk PTFE below the prominence changed to fragmented structures. With decreasing writing speed, the prominence became taller but the height peaked. The prominence gradually reduced in size after the speed reached the optimum value. We expect that these porous projections with high aspect ratio will be versatile in medical fields and microelectromechanical systems (MEMS) technology.

  14. Prominent reflector beneath around the segmentation boundary between Tonankai-Nankai earthquake area

    Science.gov (United States)

    Nakanishi, A.; Shimomura, N.; Fujie, G.; Kodaira, S.; Obana, K.; Takahashi, T.; Yamamoto, Y.; Yamashita, M.; Takahashi, N.; Kaneda, Y.; Mochizuki, K.; Kato, A.; Iidaka, T.; Kurashimo, E.; Shinohara, M.; Takeda, T.; Shiomi, K.

    2013-12-01

    In the Nankai Trough subduction seismogenic zone, the Nankai and Tonankai earthquakes had often occurred simultaneously, and caused a great event. In most cases, first break of such large events of Nankai Trough usually begins from southwest off the Kii Peninsula so far. The idea of split Philippine Sea plate between the Kii Peninsula and the Shikoku Island, which explains seismicity, tectonic background, receiver function image and historical plate motion, was previously suggested. Moreover, between the Kii Peninsula and the Shikoku Island, there is a gap of deep low-frequency events observed in the belt-like zone along the strike of the subducting Philippine Sea plate. In 2010 and 2011, we conducted the large-scale high-resolution wide-angle and reflection (MCS) seismic study, and long-term observation from off Shikoku and Kii Peninsula. Marine active source seismic data have been acquired along grid two-dimensional profiles having the total length of ~800km/year. A three-dimensional seismic tomography using active and passive seismic data observed both land and ocean bottom stations have been also performed. From those data, we found a possible prominent reflector imaged in the offshore side in the Kii channel at the depth of ~18km. The velocity just beneath the reflector cannot be determined due to the lack of ray paths. Based of the amplitude information, we interpret the reflector as the forearc Moho based on the velocity gap (from ~6.4km/s to ~7.4km/s). However, the reflector is shallower than the forearc Moho of other area along the Nankai Trough. Similar reflectors are recognized along other seismic profiles around the Kii channel. In this presentation, we will show the result of structure analysis to understand the peculiar structure including the prominent reflector around the Kii channel. Relation between the structure and the existence of the segmentation of the Nankai megathrust earthquake or seismic gap of the deep low-frequency events will be also

  15. What are the Progenitors of Compace, Massive, Quiescent Galaxies at z (equals) 2.3? The Population of Massive Galaxies at z (greater than) 3 From NMBS AND CANDELS

    Science.gov (United States)

    Stefanon, Mauro; Marchesini, Danilo; Rudnick, Gregory H.; Brammer, Gabriel B.; Tease, Katherine Whitaker

    2013-01-01

    Using public data from the NEWFIRM Medium-Band Survey (NMBS) and the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS), we investigate the population of massive galaxies at z > 3. The main aim of this work is to identify the potential progenitors of z 2 compact, massive, quiescent galaxies (CMQGs), furthering our understanding of the onset and evolution of massive galaxies. Our work is enabled by high-resolution images from CANDELS data and accurate photometric redshifts, stellar masses, and star formation rates (SFRs) from 37-band NMBS photometry. The total number of massive galaxies at z > 3 is consistent with the number of massive, quiescent galaxies (MQGs) at z 2, implying that the SFRs for all of these galaxies must be much lower by z 2. We discover four CMQGs at z > 3, pushing back the time for which such galaxies have been observed. However, the volume density for these galaxies is significantly less than that of galaxies at z star-forming galaxies at z 3 that are compact (Re 1010.6M; these galaxies are likely to become members of the massive, quiescent, compact galaxy population at z 2. We evolve the stellar masses and SFRs of each individual z > 3 galaxy adopting five different star formation histories (SFHs) and studying the resulting population of massive galaxies at z = 2.3. We find that declining or truncated SFHs are necessary to match the observed number density of MQGs at z 2, whereas a constant delayed-exponential SFH would result in a number density significantly smaller than observed. All of our assumed SFHs imply number densities of CMQGs at z 2 that are consistent with the observed number density. Better agreement with the observed number density of CMQGs at z 2 is obtained if merging is included in the analysis and better still if star formation quenching is assumed to shortly follow the merging event, as implied by recent models of the formation of MQGs.

  16. A massive, quiescent, population II galaxy at a redshift of 2.1

    Science.gov (United States)

    Kriek, Mariska; Conroy, Charlie; van Dokkum, Pieter G.; Shapley, Alice E.; Choi, Jieun; Reddy, Naveen A.; Siana, Brian; van de Voort, Freeke; Coil, Alison L.; Mobasher, Bahram

    2016-12-01

    Unlike spiral galaxies such as the Milky Way, the majority of the stars in massive elliptical galaxies were formed in a short period early in the history of the Universe. The duration of this formation period can be measured using the ratio of magnesium to iron abundance ([Mg/Fe]) in spectra, which reflects the relative enrichment by core-collapse and type Ia supernovae. For local galaxies, [Mg/Fe] probes the combined formation history of all stars currently in the galaxy, including younger and metal-poor stars that were added during late-time mergers. Therefore, to directly constrain the initial star-formation period, we must study galaxies at earlier epochs. The most distant galaxy for which [Mg/Fe] had previously been measured is at a redshift of z ≈ 1.4, with [Mg/Fe] = . A slightly earlier epoch (z ≈ 1.6) was probed by combining the spectra of 24 massive quiescent galaxies, yielding an average [Mg/Fe] = 0.31 ± 0.12 (ref. 7). However, the relatively low signal-to-noise ratio of the data and the use of index analysis techniques for both of these studies resulted in measurement errors that are too large to allow us to form strong conclusions. Deeper spectra at even earlier epochs in combination with analysis techniques based on full spectral fitting are required to precisely measure the abundance pattern shortly after the major star-forming phase (z > 2). Here we report a measurement of [Mg/Fe] for a massive quiescent galaxy at a redshift of z = 2.1, when the Universe was three billion years old. With [Mg/Fe] = 0.59 ± 0.11, this galaxy is the most Mg-enhanced massive galaxy found so far, having twice the Mg enhancement of similar-mass galaxies today. The abundance pattern of the galaxy is consistent with enrichment exclusively by core-collapse supernovae and with a star-formation timescale of 0.1 to 0.5 billion years—characteristics that are similar to population II stars in the Milky Way. With an average past star

  17. CANDELS: THE PROGENITORS OF COMPACT QUIESCENT GALAXIES AT z {approx} 2

    Energy Technology Data Exchange (ETDEWEB)

    Barro, Guillermo; Faber, S. M.; Koo, David C.; Kocevski, Dale D.; Trump, Jonathan R.; Mozena, Mark; McGrath, Elizabeth; Cheung, Edmond; Fang, Jerome [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Perez-Gonzalez, Pablo G. [Departamento de Astrof isica, Facultad de CC F isicas, Universidad Complutense de Madrid, F. CC. Fisicas, E-28040 Madrid (Spain); Williams, Christina C. [Astronomy Department, University of Massachusetts, 710 N. Pleasant Street, Amherst, MA 01003 (United States); Van der Wel, Arjen [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Wuyts, Stijn [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, Giessenbachstr., D-85741 Garching (Germany); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Croton, Darren J. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Ceverino, Daniel; Dekel, Avishai [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Ferguson, Henry C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Fontana, Adriano [INAF Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monteporzio, Rome (Italy); and others

    2013-03-10

    We combine high-resolution Hubble Space Telescope/WFC3 images with multi-wavelength photometry to track the evolution of structure and activity of massive (M{sub *} > 10{sup 10} M{sub Sun }) galaxies at redshifts z = 1.4-3 in two fields of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. We detect compact, star-forming galaxies (cSFGs) whose number densities, masses, sizes, and star formation rates (SFRs) qualify them as likely progenitors of compact, quiescent, massive galaxies (cQGs) at z = 1.5-3. At z {approx}> 2, cSFGs present SFR = 100-200 M{sub Sun} yr{sup -1}, yet their specific star formation rates (sSFR {approx} 10{sup -9} yr{sup -1}) are typically half that of other massive SFGs at the same epoch, and host X-ray luminous active galactic nuclei (AGNs) 30 times ({approx}30%) more frequently. These properties suggest that cSFGs are formed by gas-rich processes (mergers or disk-instabilities) that induce a compact starburst and feed an AGN, which, in turn, quench the star formation on dynamical timescales (few 10{sup 8} yr). The cSFGs are continuously being formed at z = 2-3 and fade to cQGs down to z {approx} 1.5. After this epoch, cSFGs are rare, thereby truncating the formation of new cQGs. Meanwhile, down to z = 1, existing cQGs continue to enlarge to match local QGs in size, while less-gas-rich mergers and other secular mechanisms shepherd (larger) SFGs as later arrivals to the red sequence. In summary, we propose two evolutionary tracks of QG formation: an early (z {approx}> 2), formation path of rapidly quenched cSFGs fading into cQGs that later enlarge within the quiescent phase, and a late-arrival (z {approx}< 2) path in which larger SFGs form extended QGs without passing through a compact state.

  18. Transverse femoral implant prominence: four cases demonstrating a preventable complication for ACL reconstruction.

    Science.gov (United States)

    Argintar, Evan; Scherer, Benjamin; Jordan, Tom; Klimkiewicz, John

    2010-12-01

    Anterior cruciate ligament (ACL) tear is a commonly occurring injury that often demands surgical reconstruction. Although the utility of this operation is widely accepted, many specific components, including graft fixation technique, remain controversial. Many clinicians favor transverse femoral implant fixation for soft tissue ACL grafts. This technique can be accomplished successfully; however, in a minority of the cases, the femoral implant can be excessively prominent, leading to iatrogenic postoperative iliotibial band syndrome. This article presents 4 patients that developed postoperative iliotibial band syndrome resulting from transverse femoral implant prominence. Despite achievement of knee ligamentous stability, implant prominence compromised final clinical results following ACL reconstruction. Through change in Lysholm value, we reviewed the clinical outcomes of these patients following femoral implant hardware removal for treatment of iliotibial band syndrome. On hardware removal, all patients demonstrated complete symptomatic improvement, mirroring an average Lysholm value increase of 38. We believe transverse femoral implant prominence is avoidable, and subsequent iliotibial band syndrome is a preventable postoperative complication.

  19. Solar prominences embedded in flux ropes: morphological features and dynamics from 3D MHD simulations

    CERN Document Server

    Terradas, J; Luna, M; Oliver, R; Ballester, J L; Wright, A N

    2015-01-01

    The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov Demoulin (1999) under the regime of weak twist, the cold and dense prominence counteracts gravity by modifying the initially force-free magnetic configuration. In some cases a quasi-stationary situation is achieved after the relaxation phase, characterized by the excitation of standing vertical oscillations. These oscillations show a strong attenuation with time produced by the mechanism of continuum damping due to the inhomogeneous transition between the prominence and solar corona. The characteristic period of the vertical oscillations does not depend strongly on the twist of the flux rope. Nonlinearity is the responsible for triggering the Kelvin-Helmholtz instability associated to the vertical oscillations and that eventually produces horizontal structures. Contrary to other configurations in which the longitudinal axis of the prominence is permeated by a pe...

  20. Observaciones del disco solar y de una protuberancia quiescente en radiación ultravioleta

    Science.gov (United States)

    Cirigliano, D.; Vial, J.-C.; Rovira, M.

    Observaciones del disco solar y de una protuberancia quiescente en el rango de longitudes de onda ultravioleta fueron obtenidas con el instrumento CDS (Coronal Diagnostic Spectrograph) y SUMER (Solar Ultraviolet Measurements of emitted radiation) a bordo de la sonda SOHO. El propósito es investigar las velocidades macroscópicas de varias especies metálicas que se observan tanto en el disco solar como en el plasma de las protuberancias. Para calcular las velocidades del disco solar aplicamos una técnica mixta para modelar la distribución de estructuras en UV en el Sol quieto. Las velocidades macroscópicas en las protuberancias se calcularon a partir de los corrimientos Doppler en cada línea espectral y luego se tomaron las del disco solar como referencia. Obtuvimos valores absolutos para las velocidades macroscópicas entre 5 y 40 km/seg. También detectamos comportamientos diferentes en las velocidades de las protuberancias en el centro con respecto a los bordes.

  1. Peripheral monocyte functions and activation in patients with quiescent Crohn's disease.

    Directory of Open Access Journals (Sweden)

    David Schwarzmaier

    Full Text Available Recent developments suggest a causal link between inflammation and impaired bacterial clearance in Crohn's disease (CD due to alterations of intestinal macrophages. Studies suggest that excessive inflammation is the consequence of an underlying immunodeficiency rather than the primary cause of CD pathogenesis. We characterized phenotypic and functional features of peripheral blood monocytes of patients with quiescent CD (n = 18 and healthy controls (n = 19 by analyses of cell surface molecule expression, cell adherence, migration, chemotaxis, phagocytosis, oxidative burst, and cytokine expression and secretion with or without lipopolysaccharide (LPS priming. Peripheral blood monocytes of patients with inactive CD showed normal expression of cell surface molecules (CD14, CD16, CD116, adherence to plastic surfaces, spontaneous migration, chemotaxis towards LTB4, phagocytosis of E. coli, and production of reactive oxygen species. Interestingly, peripheral blood monocytes of CD patients secreted higher levels of IL1β (p<.05. Upon LPS priming we found a decreased release of IL10 (p<.05 and higher levels of CCL2 (p<.001 and CCL5 (p<.05. The expression and release of TNFα, IFNγ, IL4, IL6, IL8, IL13, IL17, CXCL9, and CXCL10 were not altered compared to healthy controls. Based on our phenotypic and functional studies, peripheral blood monocytes from CD patients in clinical remission were not impaired compared to healthy controls. Our results highlight that defective innate immune mechanisms in CD seems to play a role in the (inflamed intestinal mucosa rather than in peripheral blood.

  2. Columnar structure formation of a dilute suspension of settling spherical particles in a quiescent fluid

    CERN Document Server

    Huisman, Sander G; Bourgoin, Mickaël; Chouippe, Agathe; Doychev, Todor; Huck, Peter; Morales, Carla E Bello; Uhlmann, Markus; Volk, Romain

    2016-01-01

    The settling of heavy spherical particles in a column of quiescent fluid is investigated. The performed experiments cover a range of Galileo numbers ($110 \\leq \\text{Ga} \\leq 310$) for a fixed density ratio of $\\Gamma = \\rho_p/\\rho_f = 2.5$. In this regime the particles are known (M. Jenny, J. Du\\v{s}ek and G. Bouchet, Journal of Fluid Mechanics 508, 201 (2004).) to show a variety of motions. It is known that the wake undergoes several transitions for increasing $\\text{Ga}$ resulting in particle motions that are successively: vertical, oblique, oblique oscillating, and finally chaotic. Not only does this change the trajectory of single, isolated, settling particles, but it also changes the dynamics of a swarm of particles as collective effects become important even for dilute suspensions, with volume fraction up to $\\Phi_V = \\mathcal{O}\\left(10^{-3}\\right)$, which are investigated in this work. Multi-camera recordings of settling particles are recorded and tracked over time in 3 dimensions. A variety of analy...

  3. The abundance of compact quiescent galaxies since z ˜ 0.6

    Science.gov (United States)

    Charbonnier, Aldée; Huertas-Company, Marc; Gonçalves, Thiago S.; Menéndez-Delmestre, Karín; Bundy, Kevin; Galliano, Emmanuel; Moraes, Bruno; Makler, Martín; Pereira, Maria E. S.; Erben, Thomas; Hildebrandt, Hendrik; Shan, Huan-Yuan; Caminha, Gabriel B.; Grossi, Marco; Riguccini, Laurie

    2017-08-01

    We set out to quantify the number density of quiescent massive compact galaxies at intermediate redshifts. We determine structural parameters based on i-band imaging using the Canada-France-Hawaii Telescope (CFHT) equatorial Sloan Digital Sky Survey (SDSS) Stripe 82 (CS82) survey (˜170 deg2) taking advantage of an exquisite median seeing of ˜0.6 arcsec. We select compact massive (M⋆ > 5 × 1010 M⊙) galaxies within the redshift range of 0.2 10. We systematically measure a factor of ˜5 more compacts at the same redshift than what was previously reported on smaller fields with Hubble Space Telescope (HST) imaging, which are more affected by cosmic variance. This means that the decrease in number density from z ˜ 1.5 to z ˜ 0.2 might be only of a factor of ˜2-5, significantly smaller than what was previously reported. This supports progenitor bias as the main contributor to the size evolution. This milder decrease is roughly compatible with the predictions from recent numerical simulations. Only the most extreme compact galaxies, with Reff 1010.7 M⊙, appear to drop in number by a factor of ˜20 and hence likely experience a noticeable size evolution.

  4. Characterization of metabolically quiescent Leishmania parasites in murine lesions using heavy water labeling.

    Directory of Open Access Journals (Sweden)

    Joachim Kloehn

    2015-02-01

    Full Text Available Information on the growth rate and metabolism of microbial pathogens that cause long-term chronic infections is limited, reflecting the absence of suitable tools for measuring these parameters in vivo. Here, we have measured the replication and physiological state of Leishmania mexicana parasites in murine inflammatory lesions using 2H2O labeling. Infected BALB/c mice were labeled with 2H2O for up to 4 months, and the turnover of parasite DNA, RNA, protein and membrane lipids estimated from the rate of deuterium enrichment in constituent pentose sugars, amino acids, and fatty acids, respectively. We show that the replication rate of parasite stages in these tissues is very slow (doubling time of ~12 days, but remarkably constant throughout lesion development. Lesion parasites also exhibit markedly lower rates of RNA synthesis, protein turnover and membrane lipid synthesis than parasite stages isolated from ex vivo infected macrophages or cultured in vitro, suggesting that formation of lesions induces parasites to enter a semi-quiescent physiological state. Significantly, the determined parasite growth rate accounts for the overall increase in parasite burden indicating that parasite death and turnover of infected host cells in these lesions is minimal. We propose that the Leishmania response to lesion formation is an important adaptive strategy that minimizes macrophage activation, providing a permissive environment that supports progressive expansion of parasite burden. This labeling approach can be used to measure the dynamics of other host-microbe interactions in situ.

  5. Targeting Mitochondrial Function to Treat Quiescent Tumor Cells in Solid Tumors

    Directory of Open Access Journals (Sweden)

    Xiaonan Zhang

    2015-11-01

    Full Text Available The disorganized nature of tumor vasculature results in the generation of microenvironments characterized by nutrient starvation, hypoxia and accumulation of acidic metabolites. Tumor cell populations in such areas are often slowly proliferating and thus refractory to chemotherapeutical drugs that are dependent on an active cell cycle. There is an urgent need for alternative therapeutic interventions that circumvent growth dependency. The screening of drug libraries using multicellular tumor spheroids (MCTS or glucose-starved tumor cells has led to the identification of several compounds with promising therapeutic potential and that display activity on quiescent tumor cells. Interestingly, a common theme of these drug screens is the recurrent identification of agents that affect mitochondrial function. Such data suggest that, contrary to the classical Warburg view, tumor cells in nutritionally-compromised microenvironments are dependent on mitochondrial function for energy metabolism and survival. These findings suggest that mitochondria may represent an “Achilles heel” for the survival of slowly-proliferating tumor cells and suggest strategies for the development of therapy to target these cell populations.

  6. Massive quiescent cores in Orion. IV. Their supercritical state revealed by high resolution ammonia maps

    CERN Document Server

    Li, D; Zhang, Q; Chen, W

    2012-01-01

    We present combined VLA and GBT images of \\ammonia\\ inversion transitions (1,1) and (2,2) toward OMC2 and OMC3. We focus on the relatively quiescent Orion cores, which are away from the Trapezium cluster and have no sign of massive protostars nor evolved star formation, such as IRAS source, water maser, and methanol maser. The 5\\arcsec\\ angular resolution and $0.6 \\rm{}km s^{-1}$ velocity resolution of these data enable us to study the thermal and dynamic state of these cores at $\\sim{}0.02 \\rm{}pc$ scales, comparable to or smaller than those of the current dust continuum surveys. We measure temperatures for a total of 30 cores, with average masses and radii of $11 \\Ms$ and $0.039 \\rm{}pc$, respectively. Compared to other Gould Belt dense cores, the Orion cores have an unusually high gravitational-to-inetic energy ratio (virial mass ratio $R_{vir} > >1$), resembling results for other clouds forming high--mass stars. This results from Orion cores having velocity dispersions similar to those in, e.g., Perseus a...

  7. Comparison of quiescent inflow single-shot and native space for nonenhanced peripheral MR angiography.

    Science.gov (United States)

    Ward, Emily V; Galizia, Mauricio S; Usman, Asad; Popescu, Andrada R; Dunkle, Eugene; Edelman, Robert R

    2013-12-01

    To evaluate two nonenhanced MRA methods: quiescent-interval single-shot (QISS) and Native SPACE (NATIVE = Non-contrast Angiography of the Arteries and Veins; SPACE = Sampling Perfection with Application Optimized Contrast by using different flip angle Evolution), using contrast-enhanced MR angiography (CEMRA) as a reference standard. Twenty patients (14 male; mean, 69.3 years old) referred for lower extremity MRA were recruited in a HIPAA-compliant prospective study. QISS and Native SPACE of the lower extremities were performed at 1.5 Tesla with a hybrid dual-injection contrast-enhanced MRA as reference. Image quality and stenosis severity were assessed in segments by two blinded radiologists. Methods were compared with logistic regression for correlated data for diagnostic accuracy. Of 496 arterial segments, 24 were considered nondiagnostic on the Native SPACE images. There were no QISS or CEMRA imaging segments considered to be nondiagnostic. Image quality was significantly higher for QISS than for Native SPACE. QISS stenosis sensitivity (84.9%) was not significantly different from Native SPACE (87.3%). QISS had better specificity (95.6%) than Native SPACE (87.0%), P = 0.0041. In comparison with QISS, Native SPACE proved less robust for imaging of the abdominal and pelvic segments. Native SPACE and QISS were sensitive for hemodynamically significant stenosis in this pilot study. QISS NEMRA demonstrated superior specificity and image quality, and was more robust in the abdominal and pelvic regions. Copyright © 2013 Wiley Periodicals, Inc.

  8. Formation and Collapse of Quiescent Cloud Cores Induced by Dynamic Compressions

    CERN Document Server

    Gómez, Gilberto C; Shadmehri, Mohsen; Vázquez-Semadeni, Enrique

    2007-01-01

    We present numerical hydrodynamical simulations of the formation, evolution and gravitational collapse of isothermal molecular cloud cores induced by generic turbulent compressions in spherical geometry. A compressive wave is set up in a constant sub-Jeans density distribution. As the wave travels through the simulation grid, a shock-bounded layer is formed. The inner shock of this layer reaches and bounces off the center, leaving behind a central core with an initial almost uniform density distribution, surrounded by an envelope consisting of the material in the shock-bounded shell, with a power-law density profile with index close to -2 even in non-collapsing cases. The resulting density structure resembles a quiescent core of radius < 0.1 pc, with a Bonnor-Ebert-like (BE-like) profile, although it has significant dynamical differences: it is initially non-self-gravitating and confined by the ram pressure of the infalling material, and consequently, growing continuously in mass and size. With the appropi...

  9. Are radio galaxies and quiescent galaxies different? Results from the analysis of HST brightness profiles

    CERN Document Server

    De Ruiter, H R; Capetti, A; Fanti, R; Morganti, R; Santantonio, L

    2005-01-01

    We present a study of the optical brightness profiles of early type galaxies, using a number of samples of radio galaxies and optically selected elliptical galaxies. For the radio galaxy samples--B2 of Fanaroff-Riley type I and 3C of Fanaroff-Riley type II-- we determined a number of parameters that describe a "Nuker-law" profile, which were compared with those already known for the optically selected objects. We find that radio active galaxies are always of the "core" type (i.e. an inner Nuker law slope gamma 0.5). This difference is not due to any effect with absolute magnitude, since in a region of overlap in magnitude the dichotomy between radio active and radio quiescent galaxies remains. We speculate that core-type objects represent the galaxies that have been, are, or may become, radio active at some stage in their lives; active and non-active core-type galaxies are therefore identical in all respects except their eventual radio-activity: on HST scales we do not find any relationship between boxiness ...

  10. Submicron particle dynamics for different surfaces under quiescent and turbulent conditions

    Science.gov (United States)

    Vohra, Karn; Ghosh, Kunal; Tripathi, S. N.; Thangamani, I.; Goyal, P.; Dutta, Anu; Verma, V.

    2017-03-01

    Experiments were conducted using CsI aerosols in a small scale test chamber to simulate behaviour of aerosols in the containment of a nuclear reactor. The primary focus of the study was on submicron particles (14.3 nm-697.8 nm) due to their hazardous effect on human health. Different wall surfaces, viz., plexiglass, concrete and sandpaper were chosen to study the effect of surface roughness on dry deposition velocity under both quiescent and turbulent conditions. An analytical approach to calculate dry deposition velocity of submicron particles for rough surfaces has been proposed with an improvement in the existing parameterization for shift in the velocity boundary layer. The predicted deposition velocity with the improved parameterization was found to have better agreement with published measured data of Lai and Nazaroff (2005) compared to the existing parameterizations (Wood, 1981; Zhao and Wu, 2006b). There was a significant reduction in root mean square error (RMSE) between predicted, using the improved parameterization and measured deposition velocity (upto 100%) compared to earlier ones. The new analytical deposition approach was coupled with volume conserving semi-implicit coagulation model. This aerosol dynamic model was evaluated against explicit particle size distribution for the first time for rough surfaces. Normalized RMSE between simulated and measured particle size distribution varied in the range of 2%-20% at different instances. The model seems to closely predict submicron particle behaviour in indoor environment.

  11. Translokin (Cep57) interacts with cyclin D1 and prevents its nuclear accumulation in quiescent fibroblasts.

    Science.gov (United States)

    Ruiz-Miró, Maria; Colomina, Neus; Fernández, Rita M H; Garí, Eloi; Gallego, Carme; Aldea, Martí

    2011-05-01

    Nuclear accumulation of cyclin D1 because of altered trafficking or degradation is thought to contribute directly to neoplastic transformation and growth. Mechanisms of cyclin D1 localization in S phase have been studied in detail, but its control during exit from the cell cycle and quiescence is poorly understood. Here we report that translokin (Tlk), a microtubule-associated protein also termed Cep57, interacts with cyclin D1 and controls its nucleocytoplasmic distribution in quiescent cells. Tlk binds to regions of cyclin D1 also involved in binding to cyclin-dependent kinase 4 (Cdk4), and a fraction of cyclin D1 associates to the juxtanuclear Tlk network in the cell. Downregulation of Tlk levels results in undue nuclear accumulation of cyclin D1 and increased Cdk4-dependent phosphorylation of pRB under quiescence conditions. In turn, overexpression of Tlk prevents proper cyclin D1 accumulation in the nucleus of proliferating cells in an interaction-dependent manner, inhibits Cdk4-dependent phosphorylation of pRB and hinders cell cycle progression to S phase. We propose that the Tlk acts as a key negative regulator in the pathway that drives nuclear import of cyclin D1, thus contributing to prevent pRB inactivation and to maintain cellular quiescence.

  12. Compact star forming galaxies as the progenitors of compact quiescent galaxies: Clustering result

    Science.gov (United States)

    Lin, Xiaozhi; Fan, Lulu; Kong, Xu; Fang, Guanwen

    2017-02-01

    We present a measurement of the spatial clustering of massive compact galaxies at 1.2 ≤ z ≤ 3 in CANDELS/3D-HST fields. We obtain the correlation length for compact quiescent galaxies (cQGs) at z ∼ 1.6 of r0 = 7.1-2.6+2.3 h-1 Mpc and compact star forming galaxies (cSFGs) at z ∼ 2.5 of r0 = 7.7-2.9+2.7 h-1 Mpc assuming a power-law slope γ = 1.8 . The characteristic dark matter halo masses MH of cQGs at z ∼ 1.6 and cSFGs at z ∼ 2.5 are ∼ 7.1 ×1012h-1M⊙ and ∼ 4.4 ×1012h-1M⊙ , respectively. Our clustering result suggests that cQGs at z ∼ 1.6 are possibly the progenitors of local luminous ETGs and the descendants of cSFGs and SMGs at z > 2. Thus an evolutionary connection involving SMGs, cSFGs, QSOs, cQGs and local luminous ETGs has been indicated by our clustering result.

  13. Compact star forming galaxies as the progenitors of compact quiescent galaxies: clustering result

    CERN Document Server

    Lin, Xiaozhi; Kong, Xu; Fang, Guanwen

    2016-01-01

    We present a measurement of the spatial clustering of massive compact galaxies at $1.2\\le z \\le 3$ in CANDELS/3D-HST fields. We obtain the correlation length for compact quiescent galaxies (cQGs) at $z\\sim1.6$ of $r_{0}=7.1_{-2.6}^{+2.3}\\ h^{-1}Mpc$ and compact star forming galaxies (cSFGs) at $z\\sim2.5$ of $r_{0}=7.7_{-2.9}^{+2.7}\\ h^{-1}Mpc$ assuming a power-law slope $\\gamma =1.8$. The characteristic dark matter halo masses $M_H$ of cQGs at $z\\sim1.6$ and cSFGs at $z\\sim2.5$ are $\\sim7.1\\times 10^{12}\\ h^{-1} M_\\odot$ and $\\sim4.4\\times10^{12}\\ h^{-1} M_\\odot$, respectively. Our clustering result suggests that cQGs at $z\\sim1.6$ are possibly the progenitors of local luminous ETGs and the descendants of cSFGs and SMGs at $z>2$. Thus an evolutionary connection involving SMGs, cSFGs, QSOs, cQGs and local luminous ETGs has been indicated by our clustering result.

  14. Prominent medical journals often provide insufficient information to assess the validity of studies with negative results

    Directory of Open Access Journals (Sweden)

    Dittus Robert S

    2002-09-01

    Full Text Available Abstract Background Physicians reading the medical literature attempt to determine whether research studies are valid. However, articles with negative results may not provide sufficient information to allow physicians to properly assess validity. Methods We analyzed all original research articles with negative results published in 1997 in the weekly journals BMJ, JAMA, Lancet, and New England Journal of Medicine as well as those published in the 1997 and 1998 issues of the bimonthly Annals of Internal Medicine (N = 234. Our primary objective was to quantify the proportion of studies with negative results that comment on power and present confidence intervals. Secondary outcomes were to quantify the proportion of these studies with a specified effect size and a defined primary outcome. Stratified analyses by study design were also performed. Results Only 30% of the articles with negative results comment on power. The reporting of power (range: 15%-52% and confidence intervals (range: 55–81% varied significantly among journals. Observational studies of etiology/risk factors addressed power less frequently (15%, 95% CI, 8–21% than did clinical trials (56%, 95% CI, 46–67%, p Conclusion Prominent medical journals often provide insufficient information to assess the validity of studies with negative results.

  15. Dynamics of coronal rain and descending plasma blobs in solar prominences. I. Fully ionized case

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, R.; Soler, R.; Terradas, J. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Zaqarashvili, T. V.; Khodachenko, M. L., E-mail: ramon.oliver@uib.es [Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz (Austria)

    2014-03-20

    Observations of active regions and limb prominences often show cold, dense blobs descending with an acceleration smaller than that of free fall. The dynamics of these condensations falling in the solar corona is investigated in this paper using a simple fully ionized plasma model. We find that the presence of a heavy condensation gives rise to a dynamical rearrangement of the coronal pressure that results in the formation of a large pressure gradient that opposes gravity. Eventually this pressure gradient becomes so large that the blob acceleration vanishes or even points upward. Then, the blob descent is characterized by an initial acceleration phase followed by an essentially constant velocity phase. These two stages can be identified in published time-distance diagrams of coronal rain events. Both the duration of the first stage and the velocity attained by the blob increase for larger values of the ratio of blob to coronal density, for larger blob mass, and for smaller coronal temperature. Dense blobs are characterized by a detectable density growth (up to 60% in our calculations) and by a steepening of the density in their lower part, that could lead to the formation of a shock. They also emit sound waves that could be detected as small intensity changes with periods of the order of 100 s and lasting between a few and about 10 periods. Finally, the curvature of falling paths with large radii is only relevant when a very dense blob falls along inclined magnetic field lines.

  16. Serous macular detachment, yellow macular deposits, and prominent middle limiting membrane in multiple myeloma

    Directory of Open Access Journals (Sweden)

    Dogan B

    2015-04-01

    Full Text Available Berna Dogan,1 Muhammet Kazim Erol,1 Devrim Toslak,1 Deniz Turgut Coban,1 Mehmet Bulut,1 Ayse Cengiz,1 Esin Sogutlu Sari2 1Antalya Training and Research Hospital, Eye Clinic, Antalya, Turkey; 2Balikesir University Medicine Faculty, Eye Clinic, Balikesir, Turkey Abstract: Bone marrow-derived multiple myeloma is a type of plasma cell tumor that may be associated with ocular complications. A 52-year-old male patient was admitted to our eye clinic with the complaint of sudden visual loss and a visual acuity of 20/50 in the right eye and 20/800 in the left eye. Fundus examination revealed common flame-shaped hemorrhages, venous dilatation and tortuosity, Roth spots, serous macular detachment, and yellow macular deposits in both eyes. Evaluation with fundus fluorescein angiography, fundus autofluorescence, and spectral-domain optical coherence tomography resulted in suspicion of hyperviscosity retinopathy and referral to the hematology clinic. After hematology consultation confirmed a diagnosis of multiple myeloma, chemotherapy and plasmapheresis were initiated. Four months after presentation, best-corrected visual acuity was 20/20 in both eyes and improvement in hyperviscosity retinopathy, serous macular detachment, and yellow macular deposits was observed. Keywords: serous macular detachment, yellow macular deposit, prominent middle limiting membrane, multiple myeloma

  17. When and how does a prominence-like jet gain kinetic energy?

    CERN Document Server

    Liu, Jiajia; Liu, Rui; Zhang, Quanhao; Liu, Kai; Shen, Chenglong; Wang, S

    2014-01-01

    Jet, a considerable amount of plasma being ejected from chromosphere or lower corona into higher corona, is a common phenomenon. Usually a jet is triggered by a brightening or a flare, which provides the first driving force to push plasma upward. In this process, magnetic reconnection is thought to be the mechanism to convert magnetic energy into thermal, non-thermal and kinetic energies. However, most jets could reach an unusual high altitude and end much later than the end of its associated flare. This fact implies that there is another way to continuously transfer magnetic energy into kinetic energy even after the reconnection. The whole picture described above is well known in the community, but how and how much magnetic energy is released through the way other than the reconnection is still unclear. Here, through studying a prominence-like jet observed by SDO/AIA and STEREO-A/EUVI, we find that the continuous relaxation of the post-reconnection magnetic field structure is an important process for a jet t...

  18. Point-of-Sale Tobacco Advertising Remains Prominent in Mumbai, India

    Science.gov (United States)

    Khariwala, Samir S.; Garg, Apurva; Stepanov, Irina; Gupta, Prakash C.; Ahluwalia, Jasjit S.; Gota, Vikram; Chaturvedi, Pankaj

    2017-01-01

    Objectives In India, a 2003 law (“COPTA”) banned tobacco advertising with the exception of “point of sale” and “on-pack” advertising. Given substantial evidence regarding the impact of point of sale advertising (PoS), we analyzed the prevalence of encountering such advertising in Mumbai, India. Methods A survey was conducted of 199 current and recent former tobacco users recruited at the Tata Memorial Hospital (Mumbai). Enrollees were queried regarding their exposure to tobacco advertising in the last 30 days through multiple media sources. Descriptive epidemiologic techniques were used to characterize the data. Results Overall, 95% of participants were men and 5% were women (mean age=49 years). All were current tobacco users or quit using all forms of tobacco in the last 60 days. Participants’ responses revealed that PoS tobacco advertising had been encountered in the last 30 days for cigarettes (61%), bidis (54%), and smokeless tobacco (59%). Other forms of tobacco advertising were virtually non-existent. Conclusions PoS tobacco advertising remains prominent and highly visible to consumers in Mumbai, India, indicating corporate exploitation of a loophole in the COPTA legislation. Given the observed compliance with the currently imposed bans, revisions of COPTA to include all forms of tobacco promotion and advertising would be impactful. PMID:28217721

  19. DYNAMICS OF CORONAL RAIN AND DESCENDING PLASMA BLOBS IN SOLAR PROMINENCES. II. PARTIALLY IONIZED CASE

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, R.; Soler, R.; Terradas, J. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Zaqarashvili, T. V., E-mail: ramon.oliver@uib.es [Institute of Physics, IGAM, University of Graz, Universitätsplatz 5, 8010, Graz (Austria)

    2016-02-20

    Coronal rain clumps and prominence knots are dense condensations with chromospheric to transition region temperatures that fall down in the much hotter corona. Their typical speeds are in the range 30–150 km s{sup −1} and of the order of 10–30 km s{sup −1}, respectively, i.e., they are considerably smaller than free-fall velocities. These cold blobs contain a mixture of ionized and neutral material that must be dynamically coupled in order to fall together, as observed. We investigate this coupling by means of hydrodynamic simulations in which the coupling arises from the friction between ions and neutrals. The numerical simulations presented here are an extension of those of Oliver et al. to the partially ionized case. We find that, although the relative drift speed between the two species is smaller than 1 m s{sup −1} at the blob center, it is sufficient to produce the forces required to strongly couple charged particles and neutrals. The ionization degree has no discernible effect on the main results of our previous work for a fully ionized plasma: the condensation has an initial acceleration phase followed by a period with roughly constant velocity, and, in addition, the maximum descending speed is clearly correlated with the ratio of initial blob to environment density.

  20. Contrastive Study of English and Chinese Subjects in Perspective of Cog-nitive Prominence

    Institute of Scientific and Technical Information of China (English)

    XIU Li-li

    2016-01-01

    This present paper, in perspective of cognitive prominence, the cognitive motive on the differences between English and Chinese subjects, and then explores the interpretability of the Adaptation Theory in translating the subjects. It is discovered that the blending of the cognitive prominence and the theory of adaptation is very effective in elaborating the subtle differences of English and Chinese subjects in translation, and reasonable in expounding the infeasibility of some plausible versions.

  1. The Relation between Galaxy Structure and Spectral Type: Implications for the Buildup of the Quiescent Galaxy Population at 0.5

    CERN Document Server

    Yano, Michael; van der Wel, Arjen; Whitaker, Katherine

    2016-01-01

    We present the relation between galaxy structure and spectral type, using a K-selected galaxy sample at 0.51.5 and significantly smaller than all other galaxy types at the same redshift. This result suggests that the suppression of star formation may be associated with significant structural evolution at z>1.5. At z<1, galaxy types with intermediate sSFRs (10^{-11.5}-10^{-10.5} yr^-1) do not have post-starburst SED shapes. These galaxies have similar sizes as older quiescent galaxies, implying that they can passively evolve onto the quiescent sequence, without increasing the average size of the quiescent galaxy population.

  2. Targeting of cytosolic phospholipase A2α impedes cell cycle re-entry of quiescent prostate cancer cells.

    Science.gov (United States)

    Yao, Mu; Xie, Chanlu; Kiang, Mei-Yee; Teng, Ying; Harman, David; Tiffen, Jessamy; Wang, Qian; Sved, Paul; Bao, Shisan; Witting, Paul; Holst, Jeff; Dong, Qihan

    2015-10-27

    Cell cycle re-entry of quiescent cancer cells has been proposed to be involved in cancer progression and recurrence. Cytosolic phospholipase A2α (cPLA2α) is an enzyme that hydrolyzes membrane glycerophospholipids to release arachidonic acid and lysophospholipids that are implicated in cancer cell proliferation. The aim of this study was to determine the role of cPLA2α in cell cycle re-entry of quiescent prostate cancer cells. When PC-3 and LNCaP cells were rendered to a quiescent state, the active form of cPLA2α with a phosphorylation at Ser505 was lower compared to their proliferating state. Conversely, the phospho-cPLA2α levels were resurgent during the induction of cell cycle re-entry. Pharmacological inhibition of cPLA2α with Efipladib upon induction of cell cycle re-entry inhibited the re-entry process, as manifested by refrained DNA synthesis, persistent high proportion of cells in G0/G1 and low percentage of cells in S and G2/M phases, together with a stagnant recovery of Ki-67 expression. Simultaneously, Efipladib prohibited the emergence of Skp2 while maintained p27 at a high level in the nuclear compartment during cell cycle re-entry. Inhibition of cPLA2α also prevented an accumulation of cyclin D1/CDK4, cyclin E/CDK2, phospho-pRb, pre-replicative complex proteins CDC6, MCM7, ORC6 and DNA synthesis-related protein PCNA during induction of cell cycle re-entry. Moreover, a pre-treatment of the prostate cancer cells with Efipladib during induction of cell cycle re-entry subsequently compromised their tumorigenic capacity in vivo. Hence, cPLA2α plays an important role in cell cycle re-entry by quiescent prostate cancer cells.

  3. Expression of herpes simplex virus 1 microRNAs in cell culture models of quiescent and latent infection.

    Science.gov (United States)

    Jurak, Igor; Hackenberg, Michael; Kim, Ju Youn; Pesola, Jean M; Everett, Roger D; Preston, Chris M; Wilson, Angus C; Coen, Donald M

    2014-02-01

    To facilitate studies of herpes simplex virus 1 latency, cell culture models of quiescent or latent infection have been developed. Using deep sequencing, we analyzed the expression of viral microRNAs (miRNAs) in two models employing human fibroblasts and one using rat neurons. In all cases, the expression patterns differed from that in productively infected cells, with the rat neuron pattern most closely resembling that found in latently infected human or mouse ganglia in vivo.

  4. Quiescent Luminous Red Galaxies (LRGs) as Cosmic Chronometers: on the Significance of the Mass and Environmental Dependence

    CERN Document Server

    Liu, Gaochao; Xie, Lizhi; Chen, Xuelei; Zhao, Yongheng

    2016-01-01

    Massive luminous red galaxies (LRGs) are believed to be evolving passively and can be used as cosmic chronometers to estimate the Hubble constant. However, different LRGs may locate in different environments. The environmental effects may limit the use of the LRGs as cosmic chronometers. We aim to investigate the environmental and mass dependence of the formation of "quiescent" LRGs selected from the Sloan Digital Sky Survey Date Release 8 and to pave the way for using the LRGs as cosmic chronometers. Using the population synthesis software STARLIGHT, we derive the stellar populations in each LRG through the full spectrum fitting and obtain the mean age distribution and the mean star formation history (SFH) of those LRGs. We find that there is no apparent dependence of the mean age and the SFH of quiescent LRGs on their environment, while the ages of those quiescent LRGs weakly depend on their mass. We compare the SFHs of the SDSS LRGs with those obtained from a semi-analytical galaxy formation model, and fin...

  5. CANDELS+3D-HST: compact SFGs at z~2-3, the progenitors of the first quiescent galaxies

    CERN Document Server

    Barro, G; Perez-Gonzalez, P G; Pacifici, C; Trump, J R; Koo, D C; Wuyts, S; Guo, Y; Bell, E; Dekel, A; Porter, L; Primack, J; Ferguson, H; Ashby, M; Caputi, K; Ceverino, D; Croton, D; Fazio, G; Giavalisco, M; Hsu, L; Kocevski, D; Koekemoer, A; Kurczynski, P; Kollipara, P; Lee, J; McIntosh, D; McGrath, E; Moody, C; Somerville, R; Papovich, C; Salvato, M; Santini, P; Williams, C C; Willner, S; Zolotov, A

    2013-01-01

    We analyze the star-forming and structural properties of 45 massive (log(M/Msun)>10) compact star-forming galaxies (SFGs) at 2quiescent galaxies at z~2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are heavily obscured. Nearly half (47%) host an X-ray bright AGN. In contrast, only about 10% of other massive galaxies at that time host AGNs. Compact SFGs have centrally-concentrated light profiles and spheroidal morphologies similar to quiescent galaxies, and are thus strikingly different from other SFGs. Most compact SFGs lie either within the SFR-M main sequence (65%) or below (30%), on the expected evolutionary path towards quiescent galaxies. These results show conclusively that galaxies become more compact before they lose their gas and dust, quenching star formation. Using extensive HST photometry from CANDELS and grism spectroscopy from the 3D-HST survey, we model their stellar populations with either expon...

  6. X-ray and UV correlation in the quiescent emission of Cen X-4, evidence of accretion and reprocessing

    Directory of Open Access Journals (Sweden)

    Bernardini F.

    2014-01-01

    Full Text Available We conducted the first long-term (60 days, multiwavelength (optical, ultraviolet, and X-ray simultaneous monitoring of Cen X-4 with daily Swift observations, with the goal of understanding variability in the low mass X-ray binary Cen X-4 during quiescence. We found Cen X-4 to be highly variable in all energy bands on timescales from days to months, with the strongest quiescent variability a factor of 22 drop in the X-ray count rate in only 4 days. The X-ray, UV and optical (V band emission are correlated on timescales down to less than 110 s. The shape of the correlation is a power law with index γ about 0.2–0.6. The X-ray spectrum is well fitted by a hydrogen NS atmosphere (kT = 59 − 80 eV and a power law (with spectral index Γ = 1.4 − 2.0, with the spectral shape remaining constant as the flux varies. Both components vary in tandem, with each responsible for about 50% of the total X-ray flux, implying that they are physically linked. We conclude that the X-rays are likely generated by matter accreting down to the NS surface. Moreover, based on the short timescale of the correlation, we also unambiguously demonstrate that the UV emission can not be due to either thermal emission from the stream impact point, or a standard optically thick, geometrically thin disc. The spectral energy distribution shows a small UV emitting region, too hot to arise from the accretion disk, that we identified as a hot spot on the companion star. Therefore, the UV emission is most likely produced by reprocessing from the companion star, indeed the vertical size of the disc is small and can only reprocess a marginal fraction of the X-ray emission. We also found the accretion disc in quiescence to likely be UV faint, with a minimal contribution to the whole UV flux.

  7. INFRARED SPECTROSCOPIC SURVEY OF THE QUIESCENT MEDIUM OF NEARBY CLOUDS. I. ICE FORMATION AND GRAIN GROWTH IN LUPUS

    Energy Technology Data Exchange (ETDEWEB)

    Boogert, A. C. A. [IPAC, NASA Herschel Science Center, Mail Code 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Chiar, J. E. [SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Knez, C.; Mundy, L. G. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Öberg, K. I. [Departments of Chemistry and Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Pendleton, Y. J. [Solar System Exploration Research Virtual Institute, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Tielens, A. G. G. M.; Van Dishoeck, E. F., E-mail: aboogert@ipac.caltech.edu [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2013-11-01

    Infrared photometry and spectroscopy (1-25 μm) of background stars reddened by the Lupus molecular cloud complex are used to determine the properties of grains and the composition of ices before they are incorporated into circumstellar envelopes and disks. H{sub 2}O ices form at extinctions of A{sub K} = 0.25 ± 0.07 mag (A{sub V} = 2.1 ± 0.6). Such a low ice formation threshold is consistent with the absence of nearby hot stars. Overall, the Lupus clouds are in an early chemical phase. The abundance of H{sub 2}O ice (2.3 ± 0.1 × 10{sup –5} relative to N{sub H}) is typical for quiescent regions, but lower by a factor of three to four compared to dense envelopes of young stellar objects. The low solid CH{sub 3}OH abundance (<3%-8% relative to H{sub 2}O) indicates a low gas phase H/CO ratio, which is consistent with the observed incomplete CO freeze out. Furthermore it is found that the grains in Lupus experienced growth by coagulation. The mid-infrared (>5 μm) continuum extinction relative to A{sub K} increases as a function of A{sub K}. Most Lupus lines of sight are well fitted with empirically derived extinction curves corresponding to R{sub V} ∼ 3.5 (A{sub K} = 0.71) and R{sub V} ∼ 5.0 (A{sub K} = 1.47). For lines of sight with A{sub K} > 1.0 mag, the τ{sub 9.7}/A{sub K} ratio is a factor of two lower compared to the diffuse medium. Below 1.0 mag, values scatter between the dense and diffuse medium ratios. The absence of a gradual transition between diffuse and dense medium-type dust indicates that local conditions matter in the process that sets the τ{sub 9.7}/A{sub K} ratio. This process is likely related to grain growth by coagulation, as traced by the A{sub 7.4}/A{sub K} continuum extinction ratio, but not to ice mantle formation. Conversely, grains acquire ice mantles before the process of coagulation starts.

  8. The effects of magnetic-field geometry on longitudinal oscillations of solar prominences: Cross-sectional area variation for thin tubes

    CERN Document Server

    Luna, M; Oliver, R; Terradas, J; Karpen, J

    2016-01-01

    Solar prominences are subject to both field-aligned (longitudinal) and transverse oscillatory motions, as evidenced by an increasing number of observations. Large-amplitude longitudinal motions provide valuable information on the geometry of the filament-channel magnetic structure that supports the cool prominence plasma against gravity. Our pendulum model, in which the restoring force is the gravity projected along the dipped field lines of the magnetic structure, best explains these oscillations. However, several factors can influence the longitudinal oscillations, potentially invalidating the pendulum model. The aim of this work is to study the influence of large-scale variations in the magnetic field strength along the field lines, i.e., variations of the cross-sectional area along the flux tubes supporting prominence threads. We studied the normal modes of several flux tube configurations, using linear perturbation analysis, to assess the influence of different geometrical parameters on the oscillation p...

  9. The carbon inventory in a quiescent, filamentary molecular cloud in G328

    Energy Technology Data Exchange (ETDEWEB)

    Burton, Michael G.; Ashley, Michael C. B.; Braiding, Catherine; Storey, John W. V. [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Kulesa, Craig [Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Hollenbach, David J. [Carl Sagan Center, SETI Institute, 189 Bernado Avenue, Mountain View, CA 94043-5203 (United States); Wolfire, Mark [Astronomy Department, University of Maryland, College Park, MD 20742 (United States); Glück, Christian [KOSMA, I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany); Rowell, Gavin, E-mail: m.burton@unsw.edu.au [School of Chemistry and Physics, University of Adelaide, Adelaide, SA 5005 (Australia)

    2014-02-20

    We present spectral line images of [C I] 809 GHz, CO J = 1-0 115 GHz and H I 1.4 GHz line emission, and calculate the corresponding C, CO and H column densities, for a sinuous, quiescent giant molecular cloud about 5 kpc distant along the l = 328° sightline (hereafter G328) in our Galaxy. The [C I] data comes from the High Elevation Antarctic Terahertz telescope, a new facility on the summit of the Antarctic plateau where the precipitable water vapor falls to the lowest values found on the surface of the Earth. The CO and H I data sets come from the Mopra and Parkes/ATCA telescopes, respectively. We identify a filamentary molecular cloud, ∼75 × 5 pc long with mass ∼4 × 10{sup 4} M {sub ☉} and a narrow velocity emission range of just 4 km s{sup –1}. The morphology and kinematics of this filament are similar in CO, [C I], and H I, though in the latter appears as self-absorption. We calculate line fluxes and column densities for the three emitting species, which are broadly consistent with a photodissociation region model for a GMC exposed to the average interstellar radiation field. The [C/CO] abundance ratio averaged through the filament is found to be approximately unity. The G328 filament is constrained to be cold (T {sub Dust} < 20 K) by the lack of far-IR emission, to show no clear signs of star formation, and to only be mildly turbulent from the narrow line width. We suggest that it may represent a GMC shortly after formation, or perhaps still in the process of formation.

  10. Paleoseismicity of two historically quiescent faults in Australia: Implications for fault behavior in stable continental regions

    Science.gov (United States)

    Crone, A.J.; De Martini, P. M.; Machette, M.M.; Okumura, K.; Prescott, J.R.

    2003-01-01

    Paleoseismic studies of two historically aseismic Quaternary faults in Australia confirm that cratonic faults in stable continental regions (SCR) typically have a long-term behavior characterized by episodes of activity separated by quiescent intervals of at least 10,000 and commonly 100,000 years or more. Studies of the approximately 30-km-long Roopena fault in South Australia and the approximately 30-km-long Hyden fault in Western Australia document multiple Quaternary surface-faulting events that are unevenly spaced in time. The episodic clustering of events on cratonic SCR faults may be related to temporal fluctuations of fault-zone fluid pore pressures in a volume of strained crust. The long-term slip rate on cratonic SCR faults is extremely low, so the geomorphic expression of many cratonic SCR faults is subtle, and scarps may be difficult to detect because they are poorly preserved. Both the Roopena and Hyden faults are in areas of limited or no significant seismicity; these and other faults that we have studied indicate that many potentially hazardous SCR faults cannot be recognized solely on the basis of instrumental data or historical earthquakes. Although cratonic SCR faults may appear to be nonhazardous because they have been historically aseismic, those that are favorably oriented for movement in the current stress field can and have produced unexpected damaging earthquakes. Paleoseismic studies of modern and prehistoric SCR faulting events provide the basis for understanding of the long-term behavior of these faults and ultimately contribute to better seismic-hazard assessments.

  11. Integrative miRNA and Gene Expression Profiling Analysis of Human Quiescent Hepatic Stellate Cells.

    Science.gov (United States)

    Coll, Mar; El Taghdouini, Adil; Perea, Luis; Mannaerts, Inge; Vila-Casadesús, Maria; Blaya, Delia; Rodrigo-Torres, Daniel; Affò, Silvia; Morales-Ibanez, Oriol; Graupera, Isabel; Lozano, Juan José; Najimi, Mustapha; Sokal, Etienne; Lambrecht, Joeri; Ginès, Pere; van Grunsven, Leo A; Sancho-Bru, Pau

    2015-06-22

    Unveiling the regulatory pathways maintaining hepatic stellate cells (HSC) in a quiescent (q) phenotype is essential to develop new therapeutic strategies to treat fibrogenic diseases. To uncover the miRNA-mRNA regulatory interactions in qHSCs, HSCs were FACS-sorted from healthy livers and activated HSCs (aHSCs) were generated in vitro. MiRNA Taqman array analysis showed HSCs expressed a low number of miRNAs (n = 259), from which 47 were down-regulated and 212 up-regulated upon activation. Computational integration of miRNA and gene expression profiles revealed that 66% of qHSC-associated miRNAs correlated with more than 6 altered target mRNAs (17,28 ± 10,7 targets/miRNA) whereas aHSC-associated miRNAs had an average of 1,49 targeted genes. Interestingly, interaction networks generated by miRNA-targeted genes in qHSCs were associated with key HSC activation processes. Next, selected miRNAs were validated in healthy and cirrhotic human livers and miR-192 was chosen for functional analysis. Down-regulation of miR-192 in HSCs was found to be an early event during fibrosis progression in mouse models of liver injury. Moreover, mimic assays for miR-192 in HSCs revealed its role in HSC activation, proliferation and migration. Together, these results uncover the importance of miRNAs in the maintenance of the qHSC phenotype and form the basis for understanding the regulatory networks in HSCs.

  12. HAWAIIAN SKIRT regulates the quiescent center-independent meristem activity in Arabidopsis roots.

    Science.gov (United States)

    Kim, Eun-Sol; Choe, Goh; Sebastian, Jose; Ryu, Kook Hui; Mao, Linyong; Fei, Zhangjun; Lee, Ji-Young

    2016-06-01

    Root apical meristem (RAM) drives post-embryonic root growth by constantly supplying cells through mitosis. It is composed of stem cells and their derivatives, the transit-amplifying (TA) cells. Stem cell organization and its maintenance in the RAM are well characterized, however, their relationships with TA cells remain unclear. SHORTROOT (SHR) is critical for root development. It patterns cell types and promotes the post-embryonic root growth. Defective root growth in the shr has been ascribed to the lack of quiescent center (QC), which maintains the surrounding stem cells. However, our recent investigation indicated that SHR maintains TA cells independently of QC by modulating PHABULOSA (PHB) through miRNA165/6. PHB controls TA cell activity by modulating cytokinin levels and type B Arabidopsis Response Regulator activity, in a dosage-dependent manner. To further understand TA cell regulation, we conducted a shr suppressor screen. With an extensive mutagenesis screen followed by genome sequencing of a pooled F2 population, we discovered two suppressor alleles with mutations in HAWAIIAN SKIRT (HWS). HWS, encoding an F-box protein with kelch domain, is expressed, partly depending on SHR, in the root cap and in the pericycle of the differentiation zone. Interestingly, root growth in the shr hws was more active than the wild-type roots for the first 7 days after germination, without recovering QC. Contrary to shr phb, shr hws did not show a recovery of cytokinin signaling. These indicate that HWS affects QC-independent TA cell activities through a pathway distinctive from PHB. © 2016 Scandinavian Plant Physiology Society.

  13. Evaluation of Peripheral Arterial Disease with Nonenhanced Quiescent-Interval Single-Shot MR Angiography

    Science.gov (United States)

    Hodnett, Philip A.; Koktzoglou, Ioannis; Davarpanah, Amir H.; Scanlon, Timothy G.; Collins, Jeremy D.; Sheehan, John J.; Dunkle, Eugene E.; Gupta, Navyash; Carr, James C.

    2011-01-01

    Purpose: To assess the diagnostic performance of quiescent-interval single-shot (QISS) magnetic resonance (MR) angiography, a nonenhanced two-dimensional electrocardiographically gated single-shot balanced steady-state free precession examination for the evaluation of symptomatic chronic lower limb ischemia. Materials and Methods: For this prospective institutional review board–approved, HIPAA-compliant study, the institutional review board waived the requirement for informed patient consent. The QISS nonenhanced MR angiography technique was evaluated in a two-center trial involving 53 patients referred for lower extremity MR angiography for suspected or known chronic peripheral arterial disease (PAD), with contrast material–enhanced MR angiography serving as the noninvasive reference standard. The accuracy of stenosis assessments performed with the nonenhanced MR angiography sequence was evaluated relative to the reference standard. Per-segment, per-region, and per-limb sensitivities and specificities were calculated, and assessments were considered correct only if they were in exact agreement with the reference standard–derived assessments. Generalized estimating equation (GEE) modeling with use of an unstructured binomial logit analysis was used to account for clustering of multiple measurements per case. The sensitivity and specificity of QISS MR angiography for the determination of nonsignificant (MR angiography was found to be nearly equivalent to the diagnostic performances of contrast-enhanced MR angiography and digital subtraction angiography. Non-GEE segment-based analysis revealed that for the two reviewers, nonenhanced MR angiography had sensitivities of 89.7% (436 of 486 segments) and 87.0% (423 of 486 segments) and specificities of 96.5% (994 of 1030 segments) and 94.6% (973 of 1028 segments). Conclusion: QISS nonenhanced MR angiography offers an alternative to currently used imaging tests for symptomatic chronic lower limb ischemia, for which

  14. Potentially lethal damage repair by total and quiescent tumor cells following various DNA-damaging treatments

    Energy Technology Data Exchange (ETDEWEB)

    Masunaga, Shin-ichiro; Ono, Koji; Suzuki, Minoru; Kinashi, Yuko; Takagaki, Masao [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst; Hori, Hitoshi; Kasai, Soko; Nagasawa, Hideko; Uto, Yoshihiro

    1999-08-01

    After continuous labeling of proliferating (P) cells with 5-bromo-2'-deoxyuridine (BrdU) for 5 days, SCC VII tumor-bearing mice received various kinds of DNA-damaging treatments: gamma-ray irradiation, tirapazamine (TPZ, hypoxia-specific cytotoxin) administration, or cisplatin injection. From 0.5 to 72 hr after treatment, tumors were excised, minced, and trypsinized. Single tumor cell suspensions were incubated for 48 hr with a cytokinesis-blocker, cytochalasin-B. Then, the micronucleus (MN) frequency for BrdU-unlabeled cells, quiescent (Q) cells at treatment, was determined using immunofluorescence staining for BrdU. The MN frequency for total (P+Q) cells was obtained from tumors that were not pretreated with BrdU labeling. The sensitivity to each DNA-damaging treatment was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). Treatment with gamma-rays or cisplatin resulted in a larger MN frequency in total cells than in Q cells. In contrast, TPZ treatment produced a smaller MN frequency in total cells than in Q cells. Regardless of the treatment used, Q cells showed greater repair capacities than total cells. However, TPZ caused much smaller repair capacity in both total and Q cells, compared with gamma-rays or cisplatin. Gamma-rays and cisplatin produced similar repair patterns. Differences in sensitivity between total and Q cells and repair patterns of the two cell populations were thought to depend on differences between the two cell populations in the toxicity of the DNA-damaging treatment and distribution pattern of the anticancer agent. (author)

  15. Columnar structure formation of a dilute suspension of settling spherical particles in a quiescent fluid

    Science.gov (United States)

    Huisman, Sander G.; Barois, Thomas; Bourgoin, Mickaël; Chouippe, Agathe; Doychev, Todor; Huck, Peter; Morales, Carla E. Bello; Uhlmann, Markus; Volk, Romain

    2016-11-01

    The settling of heavy spherical particles in a column of quiescent fluid is investigated. The performed experiments cover a range of Galileo numbers (110 ≤Ga≤310 ) for a fixed density ratio of Γ =ρp/ρf=2.5 . In this regime the particles are known to show a variety of motions [Jenny, Dušek, and Bouchet, Instabilities and transition of a sphere falling or ascending freely in a Newtonian fluid, J. Fluid Mech. 508, 201 (2004), 10.1017/S0022112004009164]. It is known that the wake undergoes several transitions for increasing Ga resulting in particle motions that are successively vertical, oblique, oblique oscillating, and finally chaotic. Not only does this change the trajectory of single, isolated, settling particles, but it also changes the dynamics of a swarm of particles as collective effects become important even for dilute suspensions with volume fraction up to ΦV=O (10-3) , which are investigated in this work. Multicamera recordings of settling particles are recorded and tracked over time in three dimensions. A variety of analyses are performed and show a strong clustering behavior. The distribution of the cell areas of the Voronoï tessellation in the horizontal plane is compared to that of a random distribution of particles and shows clear clustering. Moreover, a negative correlation was found between the Voronoï area and the particle velocity; clustered particles fall faster. In addition, the angle between adjacent particles and the vertical is calculated and compared to a homogeneous distribution of particles, clear evidence of vertical alignment of particles is found. The experimental findings are compared to simulations.

  16. Energy transfer between a passing vortex ring and a flexible plate in an ideal quiescent fluid

    Energy Technology Data Exchange (ETDEWEB)

    Hu, JiaCheng; Peterson, Sean D., E-mail: peterson@mme.uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Porfiri, Maurizio [Department of Mechanical and Aerospace Engineering, New York University Polytechnic School of Engineering, Brooklyn, New York 11201 (United States)

    2015-09-21

    Recent advancements in highly deformable smart materials have lead to increasing interest in small-scale energy harvesting research for powering low consumption electronic devices. One such recent experimental study by Goushcha et al. explored energy harvesting from a passing vortex ring by a cantilevered smart material plate oriented parallel to and offset from the path of the ring in an otherwise quiescent fluid. The present study focuses on modeling this experimental study using potential flow to facilitate optimization of the energy extraction from the passing ring to raise the energy harvesting potential of the device. The problem is modeled in two-dimensions with the vortex ring represented as a pair of counter-rotating free vortices. Vortex pair parameters are determined to match the convection speed of the ring in the experiments, as well as the imposed pressure loading on the plate. The plate is approximated as a Kirchhoff-Love plate and represented as a finite length vortex sheet in the fluid domain. The analytical model matches experimental measurements, including the tip displacement, the integrated force along the entire plate length as a function of vortex ring position, and the pressure along the plate. The potential flow solution is employed in a parametric study of the governing dimensionless parameters in an effort to guide the selection of plate properties for optimal energy harvesting performance. Results of the study indicate an optimal set of plate properties for a given vortex ring configuration, in which the time-scale of vortex advection matches that of the plate vibration.

  17. The cell cycle- and insulin-signaling-inhibiting miRNA expression pattern of very small embryonic-like stem cells contributes to their quiescent state.

    Science.gov (United States)

    Maj, Magdalena; Schneider, Gabriela; Ratajczak, Janina; Suszynska, Malwina; Kucia, Magda; Ratajczak, Mariusz Z

    2015-08-01

    Murine Oct4(+), very small embryonic-like stem cells (VSELs), are a quiescent stem cell population that requires a supportive co-culture layer to proliferate and/or to differentiate in vitro. Gene expression studies have revealed that the quiescence of these cells is due to changes in expression of parentally imprinted genes, including genes involved in cell cycle regulation and insulin and insulin-like growth factor signaling (IIS). To investigate the role of microRNAs (miRNAs) in VSEL quiescence, we performed miRNA studies in highly purified VSELs and observed a unique miRNA expression pattern in these cells. Specifically, we observed significant differences in the expression of certain miRNA species (relative to a reference cell population), including (i) miRNA-25_1 and miRNA-19 b, whose downregulation has the effect of upregulating cell cycle checkpoint genes and (ii) miRNA-675-3 p and miRNA-675-5 p, miRNA-292-5 p, miRNA-184, and miRNA-125 b, whose upregulation attenuates IIS. These observations are important for understanding the biology of these cells and for developing efficient ex vivo expansion strategies for VSELs isolated from adult tissues.

  18. The cell cycle- and insulin-signaling-inhibiting miRNA expression pattern of very small embryonic-like stem cells contributes to their quiescent state

    Science.gov (United States)

    Maj, Magdalena; Schneider, Gabriela; Ratajczak, Janina; Suszynska, Malwina; Kucia, Magda

    2015-01-01

    Murine Oct4+, very small embryonic-like stem cells (VSELs), are a quiescent stem cell population that requires a supportive co-culture layer to proliferate and/or to differentiate in vitro. Gene expression studies have revealed that the quiescence of these cells is due to changes in expression of parentally imprinted genes, including genes involved in cell cycle regulation and insulin and insulin-like growth factor signaling (IIS). To investigate the role of microRNAs (miRNAs) in VSEL quiescence, we performed miRNA studies in highly purified VSELs and observed a unique miRNA expression pattern in these cells. Specifically, we observed significant differences in the expression of certain miRNA species (relative to a reference cell population), including (i) miRNA-25_1 and miRNA-19 b, whose downregulation has the effect of upregulating cell cycle checkpoint genes and (ii) miRNA-675-3 p and miRNA-675-5 p, miRNA-292-5 p, miRNA-184, and miRNA-125 b, whose upregulation attenuates IIS. These observations are important for understanding the biology of these cells and for developing efficient ex vivo expansion strategies for VSELs isolated from adult tissues. PMID:25966979

  19. Prominent extraaxial CSF space on cranial ultrasound in infants: correlation with neurodevelopmental outcome

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Kyung; Lee, Mun Hyang; Yoon, Hye Kyung; Jung, Kyung Jae; Park, Won Soon; Chang, Yun Sil; Kim, Chan Gyo [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    1999-08-01

    To determine the clinical significance of prominent extra-axial CSF space (EACSFS) in infants, as seen on cranial ultrasound. Between March 1996 and November 1997, all infants who had undergone head ultrasound at our institution and were found to have prominent EACSFS were evaluated. The width of the interhemispheric fissure was measured at three locations at the level of the frontal horn, body and atrium of the lateral ventricles. The depth of the CSF space over the convexity was also measured. The average of these measurements was calculated and each patient was assigned to one of three groups: mild, moderate, or marked. Ultrasound findings were evaluated for other associated abnormalities. Clinical neurodevelopment was evaluated by a pediatric neurologist, and ultrasound and neurodevelopmental findings were correlated. Prominent EACSFS was found in 153 patients, and neurodevelopmental evaluation up to a corrected age of 9 months was available in 133. One hundred and eight of 117 infants with normal neurodevelopment had no other associated abnormality(n=81), or abnormality associated only with grade I subependymal hemorrhage or cyst(n=27). Twelve of 16 infants with an abnormal neurodevelopmental outcome had major abnormalities including PVL, grade IV hemorrhage, and marked ventriculomegaly. Prominent EACSFS alone does not appear to be clinically significant. An abnormal neurodevelopmental outcome is associated with major abnormalities seen on ultrasound. Follow-up examination for prominent EACSFS is not indicated unless the associated abnormality requires further evaluations.

  20. SOLAR PROMINENCES EMBEDDED IN FLUX ROPES: MORPHOLOGICAL FEATURES AND DYNAMICS FROM 3D MHD SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M. [Instituto de Astrofsíca de Canarias, E-38205 La Laguna, Tenerife (Spain); Wright, A. N., E-mail: jaume.terradas@uib.es [School of Mathematics and Statistics, University of St Andrews, St Andrews, KY16 9SS (United Kingdom)

    2016-04-01

    The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov and Démoulin under the regime of weak twist, the cold and dense prominence counteracts gravity by modifying the initially force-free magnetic configuration. In some cases a quasi-stationary situation is achieved after the relaxation phase, characterized by the excitation of standing vertical oscillations. These oscillations show a strong attenuation with time produced by the mechanism of continuum damping due to the inhomogeneous transition between the prominence and solar corona. The characteristic period of the vertical oscillations does not depend strongly on the twist of the flux rope. Nonlinearity is responsible for triggering the Kelvin–Helmholtz instability associated with the vertical oscillations and that eventually produces horizontal structures. Contrary to other configurations in which the longitudinal axis of the prominence is permeated by a perpendicular magnetic field, like in unsheared arcades, the orientation of the prominence along the flux rope axis prevents the development of Rayleigh–Taylor instabilities and therefore the appearance of vertical structuring along this axis.

  1. A Discourse Perspective of Topic-prominence in Chinese EFL Learners’ Interlanguage

    Directory of Open Access Journals (Sweden)

    Shaopeng Li

    2014-07-01

    Full Text Available The present study aims to investigate the general characteristics of topic-prominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from the discourse perspective. We have selected as the research target “topic chain” which is the main topic-prominent structure in Chinese discourse and “zero anaphora” which is the most common topic anaphor of topic chain. Topic structures mainly appear in Chinese discourse in the form of “topic chain” (Wang, 2002; 2004. Actually, in the event of a topic chain, research on topic structures should go into the typical range of discourse. Two important findings were yielded by the present study. First, the characteristics of Chinese topic chain are transferrable to the interlanguage of Chinese EFL learners, thus resulting in overgeneralization of zero anaphora; second, interlanguage discourse of Chinese EFL learners reflects the characteristics of a second language acquisition process from topic-prominence to subject-prominence, thus lending support to the discourse transfer hypothesis.

  2. MOIRCS Deep Survey. X. Evolution of Quiescent Galaxies as a Function of Stellar Mass at 0.5

    CERN Document Server

    Kajisawa, Masaru; Yoshikawa, Tomohiro; Yamada, Toru; Onodera, Masato; Akiyama, Masayuki; Tanaka, Ichi

    2011-01-01

    We study the evolution of quiescent galaxies at 0.56 by performing SED fitting of the multi broad-band photometry from the U to Spitzer 5.8um bands with the population synthesis model of Bruzual & Charlot (2003) where exponentially decaying star formation histories are assumed. The number density of quiescent galaxies increases by a factor of ~3 from 1.0~ 1-1.5.

  3. Simultaneous Transverse Oscillations of a Prominence and a Filament and Longitudinal Oscillation of another Filament Induced by a Single Shock Wave

    CERN Document Server

    Shen, Yuandeng; Chen, P F; Ichimoto, Kiyoshi

    2014-01-01

    We present the first stereoscopic and Doppler observations of simultaneous transverse oscillations of a prominence and a filament and longitudinal oscillation of another filament launched by a single shock wave. Using H-alpha Doppler observations, we derive the three-dimensional oscillation velocities at different heights along the prominence axis. The results indicate that the prominence has a larger oscillation amplitude and damping time at higher altitude, but the periods at different heights are the same (i.e., 13.5 minutes). This suggests that the prominence oscillates like a linear vertical rigid body with one end anchored on the Sun. One of the filaments shows weak transverse oscillation after the passing of the shock, which is possibly due to the low altitude of the filament and the weakening (due to reflection) of the shock wave before the interaction. Large amplitude longitudinal oscillation is observed in the other filament after the passing of the shock wave. The velocity amplitude and period are ...

  4. 78 FR 69691 - Draft Guidance for Industry on Product Name Placement, Size, and Prominence in Advertising and...

    Science.gov (United States)

    2013-11-20

    ..., and Prominence in Advertising and Promotional Labeling; Availability AGENCY: Food and Drug... Advertising and Promotional Labeling.'' When finalized, the draft guidance will replace the guidance of the... placement, size, prominence, and frequency in promotional labeling and advertising for prescription...

  5. Analysis and interpretation of a fast limb CME with eruptive prominence, C-flare and EUV dimming

    CERN Document Server

    Koutchmy, Serge; Filippov, Boris; Noens, Jacques-Clair; Romeuf, David; Golub, Leon

    2008-01-01

    Coronal Mass ejections or CMEs are large dynamical solar-corona events. The mass balance and kinematics of a fast limb CME, including its prominence progenitor and the associated flare, will be compared with computed magnetic structures to look for their origin and effect. Multi-wavelength ground-based and space-borne observations are used to study a fast W-limb CME event of December 2, 2003, taking into account both on and off disk observations. Its erupting prominence is measured at high cadence with the Pic du Midi full H-alpha line-flux imaging coronagraph. EUV images from space instruments are processed including difference imaging. SOHO/LASCO images are used to study the mass excess and motions. A fast bright expanding coronal loop is identified in the region recorded slightly later by GOES as a C7.2 flare, followed by a brightening and an acceleration phase of the erupting material with both cool and hot components. The total coronal radiative flux dropped by 5 percent in the EUV channels, revealing a ...

  6. Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

    Indian Academy of Sciences (India)

    Vojtech Rusin; Milan Minarovjech; Milan Rybansky

    2000-09-01

    Long-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18-23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around' cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

  7. On the robustness of the pendulum model for large-amplitude longitudinal oscillations in prominences

    CERN Document Server

    Luna, M; Khomenko, E; Collados, M; de Vicente, A

    2015-01-01

    Large-amplitude longitudinal oscillations (LALOs) in prominences are spectacular manifestations of the solar activity. In such events nearby energetic disturbances induce periodic motions on filaments with displacements comparable to the size of the filaments themselves and with velocities larger than 20 km/s. The pendulum model, in which the gravity projected along a rigid magnetic field is the restoring force, was proposed to explain these events. However, it can be objected that in a realistic situation where the magnetic field reacts to the mass motion of the heavy prominence, the simplified pendulum model could be no longer valid. We have performed non-linear time-dependent numerical simulations of LALOs considering a dipped magnetic field line structure. In this work we demonstrate that for even relatively weak magnetic fields the pendulum model works very well. We therefore validate the pendulum model and show its robustness, with important implications for prominence seismology purposes. With this mod...

  8. Subcision Using a Spinal Needle Cannula and a Thread for Prominent Nasolabial Fold Correction

    Directory of Open Access Journals (Sweden)

    Sang-Yeul Lee

    2013-05-01

    Full Text Available Deepening of the nasolabial crease is an esthetically unpleasing aging phenomenon occurring in the midface. Various treatment modalities have been introduced to improve the appearance of prominent nasolabial folds, all of which have pros and cons. Currently, a minimally invasive technique using synthetic dermal fillers is most commonly used. A simple and easy subcision procedure using a wire scalpel has also been used and reported to be effective for prominent nasolabial fold correction, with minimal complications. As an alternative to the wire scalpel, we used a 20-gauge metal type spinal needle cannula (Hakko Co. and 4-0 Vicryl suture (Ethicon Inc. for subcision of nasolabial folds. This technique is less expensive than the use of a wire scalpel and easily available when needed. Therefore, on the basis of favorable results, our modified subcision technique may be considered effective for prominent nasolabial fold correction.

  9. Establishing the Thematic Structure and Investigating the most Prominent Theta Roles Used in Sindhi Language

    Directory of Open Access Journals (Sweden)

    Zahid Ali Veesar

    2015-07-01

    Full Text Available This study focuses on the thematic structure of the Sindhi verbs to find theta roles in the Sindhi language. The study tries to answer the research questions; “What are the thematic structures of Sindhi verbs?” and “What are the prominent theta roles in the Sindhi language?” It examines the argument/thematic structure of Sindhi verbs and also finds the theta roles assigned by the Sindhi verbs to their arguments along with the most prominent theta roles used in the Sindhi language. The data come from the two interviews taken from two young native Sindhi speakers, which consist of 2 hours conversation having 1,669 sentences in natural spoken version of the Sindhi language. Towards the end, it has been found that the Sindhi language has certain theta roles which are assigned by the verbs to their arguments in sentences. Each verb phrase in our data is thus examined and studied in detail in terms of Argument/Thematic structure in order to find theta roles in Sindhi language. Thus, in this regard, each verb phrase (in a sentence has been examined with the help of Carnie’s theoretical framework (Thematic Relation and Theta Roles: 2006 in order to find the prominent theta roles in the Sindhi language. The data have been examined and analysed on the basis of the Carnie’s theoretical framework. The study finds that the Sindhi language has all (09 theta roles which have been proposed by Carnie (2006. It has been found that six prominent theta roles out of nine are used prominently in Sindhi. The six prominent theta roles in Sindhi language are: agent, theme, beneficiary, recipient, locative and goal.

  10. Spatial and temporal analysis of gene expression during growth and fusion of the mouse facial prominences.

    Science.gov (United States)

    Feng, Weiguo; Leach, Sonia M; Tipney, Hannah; Phang, Tzulip; Geraci, Mark; Spritz, Richard A; Hunter, Lawrence E; Williams, Trevor

    2009-12-16

    Orofacial malformations resulting from genetic and/or environmental causes are frequent human birth defects yet their etiology is often unclear because of insufficient information concerning the molecular, cellular and morphogenetic processes responsible for normal facial development. We have, therefore, derived a comprehensive expression dataset for mouse orofacial development, interrogating three distinct regions - the mandibular, maxillary and frontonasal prominences. To capture the dynamic changes in the transcriptome during face formation, we sampled five time points between E10.5-E12.5, spanning the developmental period from establishment of the prominences to their fusion to form the mature facial platform. Seven independent biological replicates were used for each sample ensuring robustness and quality of the dataset. Here, we provide a general overview of the dataset, characterizing aspects of gene expression changes at both the spatial and temporal level. Considerable coordinate regulation occurs across the three prominences during this period of facial growth and morphogenesis, with a switch from expression of genes involved in cell proliferation to those associated with differentiation. An accompanying shift in the expression of polycomb and trithorax genes presumably maintains appropriate patterns of gene expression in precursor or differentiated cells, respectively. Superimposed on the many coordinated changes are prominence-specific differences in the expression of genes encoding transcription factors, extracellular matrix components, and signaling molecules. Thus, the elaboration of each prominence will be driven by particular combinations of transcription factors coupled with specific cell:cell and cell:matrix interactions. The dataset also reveals several prominence-specific genes not previously associated with orofacial development, a subset of which we externally validate. Several of these latter genes are components of bidirectional

  11. Spatial and temporal analysis of gene expression during growth and fusion of the mouse facial prominences.

    Directory of Open Access Journals (Sweden)

    Weiguo Feng

    Full Text Available Orofacial malformations resulting from genetic and/or environmental causes are frequent human birth defects yet their etiology is often unclear because of insufficient information concerning the molecular, cellular and morphogenetic processes responsible for normal facial development. We have, therefore, derived a comprehensive expression dataset for mouse orofacial development, interrogating three distinct regions - the mandibular, maxillary and frontonasal prominences. To capture the dynamic changes in the transcriptome during face formation, we sampled five time points between E10.5-E12.5, spanning the developmental period from establishment of the prominences to their fusion to form the mature facial platform. Seven independent biological replicates were used for each sample ensuring robustness and quality of the dataset. Here, we provide a general overview of the dataset, characterizing aspects of gene expression changes at both the spatial and temporal level. Considerable coordinate regulation occurs across the three prominences during this period of facial growth and morphogenesis, with a switch from expression of genes involved in cell proliferation to those associated with differentiation. An accompanying shift in the expression of polycomb and trithorax genes presumably maintains appropriate patterns of gene expression in precursor or differentiated cells, respectively. Superimposed on the many coordinated changes are prominence-specific differences in the expression of genes encoding transcription factors, extracellular matrix components, and signaling molecules. Thus, the elaboration of each prominence will be driven by particular combinations of transcription factors coupled with specific cell:cell and cell:matrix interactions. The dataset also reveals several prominence-specific genes not previously associated with orofacial development, a subset of which we externally validate. Several of these latter genes are components of

  12. Solar prominences with Na and Mg emissions and centrally reversed Balmer line

    CERN Document Server

    Stellmacher, G; 10.1051/0004-6361:20041550

    2012-01-01

    We study spectral lines in exceptionally bright solar limb prominences with pronounced sodium and magnesium emission. We find that most prominences with significant NaD2 and Mgb2 emission show centrally reversed profiles of H-alpha and occasionally even of H-beta, which are are well reproduced by semi-infinite models. The maximum H-alpha source function corresponds to an excitation temperature of 3950 K, for pronounced central reversions 4000 K; the related optical thickness exceeds 10.0. The narrow widths of the NaD2 and Mgb2 profiles yield a non-thermal broadening of 5 km/s.

  13. Orientation of the linear polarization plane of H-alpha emission in prominences

    CERN Document Server

    Suyunova, E Z; Osokin, A R

    2015-01-01

    2D distributions of deviations of the polarization plane from the direction tangential to the solar limb (angle \\chi) and the sign of \\chi are presented for H{\\alpha} prominences of March 29, 2006. The obtained values of \\chi are in agreement with non-eclipse coronagraphic measurements and indicate the existence of longitudinal magnetic fields. The 2D distributions of the sign of \\chi show the existence of both {\\guillemotleft}+{\\guillemotright} and {\\guillemotleft}-{\\guillemotright} polarities for each prominence. An interpretation in the frame of the existence of oppositely directed magnetic fields is noted.

  14. A CASE STUDY OF PROSODIC PHRASAL GROUPING AND INTONATIONAL PROMINENCE IN LANGUAGE ACQUISITION

    Directory of Open Access Journals (Sweden)

    Susanto

    2016-06-01

    Full Text Available In language acquisition, children use prosody in their comprehension and production of utterances. In line with that, as a case study in this research, I analyze two particular aspects of prosody in a child’s language acquisition, i.e. prosodic phrasal grouping and intonational prominence. In the first aspect, I investigate whether the child uses prosodic phrases to group words together into interpretable units. In the second aspect, I analyze whether the child uses intonational prominence to focus marking prosody. The result indicates that both aspects are used by the child.

  15. Multiwavelength Study of Quiescent States of Mrk 421 with Unprecedented Hard X-Ray Coverage Provided by NuSTAR in 2013

    CERN Document Server

    Baloković, M.; Madejski, G.; Furniss, A.; Chiang, J.; Ajello, M.; Alexander, D.M.; Barret, D.; Blandford, R.; Boggs, S.E.; Christensen, F.E.; Craig, W.W.; Forster, K.; Giommi, P.; Grefenstette, B.W.; Hailey, C.J.; Harrison, F.A.; Hornstrup, A.; Kitaguchi, T.; Koglin, J.E.; Madsen, K.K.; Mao, P.H.; Miyasaka, H.; Mori, K.; Perri, M.; Pivovaroff, M.J.; Puccetti, S.; Rana, V.; Stern, D.; Tagliaferri, G.; Urry, C.M.; Westergaard, N.J.; Zhang, W.W.; Zoglauer, A.; Archambault, S.; Archer, A.A.; Barnacka, A.; Benbow, W.; Bird, R.; Buckley, J.; Bugaev, V.; Cerruti, M.; Chen, X.; Ciupik, L.; Connolly, M.P.; Cui, W.; Dickinson, H.J.; Dumm, J.; Eisch, J.D.; Falcone, A.; Feng, Q.; Finley, J.P.; Fleischhack, H.; Fortson, L.; Griffin, S.; Griffiths, S.T.; Grube, J.; Gyuk, G.; Huetten, M.; Haakansson, N.; Holder, J.; Humensky, T.B.; Johnson, C.A.; Kaaret, P.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krause, M.; Krennrich, F.; Lang, M.J.; Maier, G.; McArthur, S.; Meagher, K.; Moriarty, P.; Nelson, T.; Nieto, D.; Ong, R.A.; Park, N.; Pohl, M.; Popkow, A.; Pueschel, E.; Reynolds, P.T.; Richards, G.T.; Roache, E.; Santander, M.; Sembroski, G.H.; Shahinyan, K.; Smith, A.W.; Staszak, D.; Telezhinsky, I.; Todd, N.W.; Tucci, J.V.; Tyler, J.; Vincent, S.; Weinstein, A.; Wilhelm, A.; Williams, D.A.; Zitzer, B.; Ahnen, M.L.; Ansoldi, S.; Antonelli, L.A.; Antoranz, P.; Babic, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Chatterjee, A.; Clavero, R.; Colin, P.; Colombo, E.; Contreras, J.L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; de Angelis, A.; De Lotto, B.; Wilhelmi, E. D. de Oña; Delgado Mendez, C.; Di Pierro, F.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Elsaesser, D.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M.V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; López, R. J. García; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giammaria, P.; Eisenacher, D.; Godinović, N.; González Muñoz, A.; Guberman, D.; Hahn, A.; Hanabata, Y.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Idec, W.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Majumdar, P.; Makariev, M.; Mallot, K.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Miranda, J.M.; Mirzoyan, R.; Moralejo, A.; Moretti, E.; Nakajima, D.; Neustroev, V.; Niedzwiecki, A.; Nievas-Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Orito, R.; Overkemping, A.; Paiano, S.; Palacio, S.; Palatiello, M.; Paoletti, R.; Paredes, J.M.; Paredes-Fortuny, X.; Persic, M.; Poutanen, J.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Rhode, W.; Ribó, M.; Rico, J.; Garcia, J. Rodriguez; Saito, T.; Satalecka, K.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S.N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Stamerra, A.; Steinbring, T.; Strzys, M.; Takalo, L.O.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Torres, D.F.; Toyama, T.; Treves, A.; Verguilov, V.; Vovk, I.; Ward, J.E.; Will, M.; Wu, M.H.; Zanin, R.; Perkins, J.; Verrecchia, F.; Leto, C.; Böttcher, M.; Villata, M.; Raiteri, C.M.; Acosta-Pulido, J.A.; Bachev, R.; Berdyugin, A.; Blinov, D.A.; Carnerero, M.I.; Chen, W.P.; Chinchilla, P.; Damljanovic, G.; Eswaraiah, C.; Grishina, T.S.; Ibryamov, S.; Jordan, B.; Jorstad, S.G.; Joshi, M.; Kopatskaya, E.N.; Kurtanidze, O.M.; Kurtanidze, S.O.; Larionova, E.G.; Larionova, L.V.; Larionov, V.M.; Latev, G.; Lin, H.C.; Marscher, A.P.; Mokrushina, A.A.; Morozova, D.A.; Nikolashvili, M.G.; Semkov, E.; Strigachev, A.; Troitskaya, Yu. V.; Troitsky, I.S.; Vince, O.; Barnes, J.; Güver, T.; Moody, J.W.; Sadun, A.C.; Sun, S.; Hovatta, T.; Richards, J.L.; Max-Moerbeck, W.; Readhead, A.C.; Lähteenmäki, A.; Tornikoski, M.; Tammi, J.; Ramakrishnan, V.; Reinthal, R.; Angelakis, E.; Fuhrmann, L.; Myserlis, I.; Karamanavis, V.; Sievers, A.; Ungerechts, H.; Zensus, J.A.

    2016-01-01

    We present coordinated multiwavelength observations of the bright, nearby BL Lac object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from radio to very-high-energy (VHE) gamma-ray bands. NuSTAR yielded previously unattainable sensitivity in the 3-79 keV range, revealing that the spectrum softens when the source is dimmer until the X-ray spectral shape saturates into a steep power law with a photon index of approximately 3, with no evidence for an exponential cutoff or additional hard components up to about 80 keV. For the first time, we observed both the synchrotron and the inverse-Compton peaks of the spectral energy distribution (SED) simultaneously shifted to frequencies below the typical quiescent state by an order of magnitude. The fractional variability as a function of photon energy shows a double-bump structure which relates to the two bumps of the broadband SED. In each bump, the variabilit...

  16. AN INTEGRATED MODEL FOR THE PRODUCTION OF X-RAY TIME LAGS AND QUIESCENT SPECTRA FROM HOMOGENEOUS AND INHOMOGENEOUS BLACK HOLE ACCRETION CORONAE

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, John J.; Becker, Peter A., E-mail: jkroon@gmu.edu, E-mail: pbecker@gmu.edu [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030-4444 (United States)

    2016-04-20

    Many accreting black holes manifest time lags during outbursts, in which the hard Fourier component typically lags behind the soft component. Despite decades of observations of this phenomenon, the underlying physical explanation for the time lags has remained elusive, although there are suggestions that Compton reverberation plays an important role. However, the lack of analytical solutions has hindered the interpretation of the available data. In this paper, we investigate the generation of X-ray time lags in Compton scattering coronae using a new mathematical approach based on analysis of the Fourier-transformed transport equation. By solving this equation, we obtain the Fourier transform of the radiation Green’s function, which allows us to calculate the exact dependence of the time lags on the Fourier frequency, for both homogeneous and inhomogeneous coronal clouds. We use the new formalism to explore a variety of injection scenarios, including both monochromatic and broadband (bremsstrahlung) seed photon injection. We show that our model can successfully reproduce both the observed time lags and the time-averaged (quiescent) X-ray spectra for Cyg X-1 and GX 339-04, using a single set of coronal parameters for each source. The time lags are the result of impulsive bremsstrahlung injection occurring near the outer edge of the corona, while the time-averaged spectra are the result of continual distributed injection of soft photons throughout the cloud.

  17. Multi-Wavelength Photometric and Polarimetric Observations of the Outburst of 3C 454.3 in Dec. 2009

    CERN Document Server

    Sasada, Mahito; Fukazawa, Yasushi; Kawabata, Koji S; Itoh, Ryosuke; Sakon, Itsuki; Fujisawa, Kenta; Kadota, Akiko; Ohsugi, Takashi; Yoshida, Michitoshi; Yasuda, Hajimu; Yamanaka, Masayuki; Sato, Shuji; Kino, Masaru

    2011-01-01

    In December 2009, the bright blazar, 3C 454.3 exhibited a strong outburst in the optical, X-ray and gamma-ray regions. We performed photometric and polarimetric monitoring of this outburst in the optical and near-infrared bands with TRISPEC and HOWPol attached to the Kanata telescope. We also observed this outburst in the infrared band with AKARI, and the radio band with the 32-m radio telescope of Yamaguchi University. The object was in an active state from JD 2455055 to 2455159. It was 1.3 mag brighter than its quiescent state before JD 2455055 in the optical band. After the end of the active state in JD 2455159, a prominent outburst was observed in all wavelengths. The outburst continued for two months. Our optical and nearinfrared polarimetric observations revealed that the position angle of the polarization (PA) apparently rotated clockwise by 240 degrees within 11 d in the active state (JD 2455063-2455074), and after this rotation, PA remained almost constant during our monitoring. In the outburst state...

  18. Ice and Dust in the Quiescent Medium of Isolated Dense Cores

    Science.gov (United States)

    Boogert, A. C. A.; Huard, T. L.; Cook, A. M.; Chiar, J. E.; Knez, C.; Decin, L.; Blake, G. A.; Tielens, A. G. G. M.; van Dishoeck, E. F.

    2011-03-01

    The relation between ices in the envelopes and disks surrounding young stellar objects (YSOs) and those in the quiescent interstellar medium (ISM) is investigated. For a sample of 31 stars behind isolated dense cores, ground-based and Spitzer spectra and photometry in the 1-25 μm wavelength range are combined. The baseline for the broad and overlapping ice features is modeled, using calculated spectra of giants, H2O ice and silicates. The adopted extinction curve is derived empirically. Its high resolution allows for the separation of continuum and feature extinction. The extinction between 13 and 25 μm is ~50% relative to that at 2.2 μm. The strengths of the 6.0 and 6.85 μm absorption bands are in line with those of YSOs. Thus, their carriers, which, besides H2O and CH3OH, may include NH+ 4, HCOOH, H2CO, and NH3, are readily formed in the dense core phase, before stars form. The 3.53 μm C-H stretching mode of solid CH3OH was discovered. The CH3OH/H2O abundance ratios of 5%-12% are larger than upper limits in the Taurus molecular cloud. The initial ice composition, before star formation occurs, therefore depends on the environment. Signs of thermal and energetic processing that were found toward some YSOs are absent in the ices toward background stars. Finally, the peak optical depth of the 9.7 μm band of silicates relative to the continuum extinction at 2.2 μm is significantly shallower than in the diffuse ISM. This extends the results of Chiar et al. to a larger sample and higher extinctions. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  19. Premalignant quiescent melanocytic nevi do not express the MHC class I chain-related protein A Los nevos melanocíticos premalignos quiescentes no expresan la molécula MHC class I chain-related protein A

    Directory of Open Access Journals (Sweden)

    Mercedes B. Fuertes

    2011-08-01

    Full Text Available The MHC class I chain-related protein A (MICA is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK cells, CD8+ aßTCR and ?dTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-? secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease- induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples as well as in normal skin, benign lesions (seborrheic keratosis, premalignant lesions (actinic keratosis and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.MHC class I chain-related protein A (MICA es una molécula casi ausente en células normales pero sobre-expresada por células tumorales, que promueve el reconocimiento por células citotóxicas naturales (natural killer o NK y por

  20. Observations of the H2S toward OMC-1

    Science.gov (United States)

    Minh, Y. C.; Irvine, W. M.; Mcgonagle, D.; Ziurys, L. M.

    1990-01-01

    Observations of the 1(10) - 1(01) transition of interstellar H2S and its isotopes toward OMC-1 are reported. The fractional abundance of H2S in the quiescent regions of OMC-1 seems difficult to explain by currently known ion-molecular reactions. The fractional abundance of H2S relative to H2 is enhanced by a factor of 1000 in the hot core and the plateau relative to the quiescent clouds. The (HDS)/(H2S) abundance ratio in the hot core is estimated at 0.02 or less.

  1. Observations of the H2S toward OMC-1

    Science.gov (United States)

    Minh, Y. C.; Irvine, W. M.; Mcgonagle, D.; Ziurys, L. M.

    1990-01-01

    Observations of the 1(10) - 1(01) transition of interstellar H2S and its isotopes toward OMC-1 are reported. The fractional abundance of H2S in the quiescent regions of OMC-1 seems difficult to explain by currently known ion-molecular reactions. The fractional abundance of H2S relative to H2 is enhanced by a factor of 1000 in the hot core and the plateau relative to the quiescent clouds. The (HDS)/(H2S) abundance ratio in the hot core is estimated at 0.02 or less.

  2. INTEGRAL Observations of SGR1806-20

    Science.gov (United States)

    Hurley, K.; Mazets, E.; Golenetskii, S.; Frederiks, D.; Atteia, J. L.; Boer, M.; Brandt, S.; Lund, N.; Pedersen, H.; Cline, T.; Ibrahim, A.; Costa, E.; Feroci, M.; Ubertini, P.; Del Santo, M.; Frontera, F.; Pizzichini, G.; Castro-Tirado, A.; Gimenez, A.; Winkler, C.; Schoenfelder, V.; von Kienlin, A.; Lichti, G.; Sunyaev, R.; Kretschmar, P.; Produit, N.; Mereghetti, S.; Goetz, D.; Mirabel, F.; Woods, P.; Kouveliotou; Finger, M.; Gogus, E.; Thompson, C.; Duncan, R.; Pavlov, G.; van der Klis, M.; Molkov, S.

    2004-12-01

    INTEGRAL has observed the soft gamma repeater SGR1806-20 for over 2.2 million seconds in the course of two target of opportunity observations and two Galactic center deep exposures in the AO-1 and AO-2 periods. In these observations, the quiescent emission was detected and its spectrum measured to over 100 keV for the first time by IBIS. More than 100 bursts were detected by IBIS in the 15-200 keV energy range, and more than 30 of them were also detected by JEM-X in the 3-35 keV energy range. We discuss the fluence distribution of SGR1806 bursts, and their spectral evolution. We also set an upper limit to the quiescent flux from the SGR-like source discovered by HETE, SGR1808-20. This work was supported by the INTEGRAL U.S. Guest Investigator program under NASA grant NAG5-13738.

  3. Global and National Prominent Universities: Internationalization, Competitiveness and the Role of the State

    Science.gov (United States)

    Horta, Hugo

    2009-01-01

    This article provides a characterization of the internationalization of "global" European universities and discusses the role of the State in promoting greater internationalization and competitiveness levels of prominent national universities. The analysis supports previous arguments stating that global ranking of universities is…

  4. Global and National Prominent Universities: Internationalization, Competitiveness and the Role of the State

    Science.gov (United States)

    Horta, Hugo

    2009-01-01

    This article provides a characterization of the internationalization of "global" European universities and discusses the role of the State in promoting greater internationalization and competitiveness levels of prominent national universities. The analysis supports previous arguments stating that global ranking of universities is…

  5. Global and National Prominent Universities: Internationalization, Competitiveness and the Role of the State

    Science.gov (United States)

    Horta, Hugo

    2009-01-01

    This article provides a characterization of the internationalization of "global" European universities and discusses the role of the State in promoting greater internationalization and competitiveness levels of prominent national universities. The analysis supports previous arguments stating that global ranking of universities is strongly based on…

  6. Prominent ears: Anthropometric study of the external ear of primary school children of Harare, Zimbabwe

    Directory of Open Access Journals (Sweden)

    Wilfred Muteweye

    2015-09-01

    Conclusion: The prevalence of prominent ear among black African children in the studied population is comparable to that of Caucasians. The study provides a set of biometric data of auricular dimensions for normal black African children aged 9–13 years.

  7. Do indium 111-labeled polymorphonuclear leukocytes detect neutrophil-prominent, fibrosing lung disease in rats

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.H. Jr.; Hartman, T.M.; Lichter, J.; Moser, K.M.

    1987-07-01

    The role of polymorphonuclear leukocytes (PMNs) in fibrotic lung disease remains poorly defined, but PMN prominence may predict a poor response to therapy in some patients. The bleomycin injury to rats represents a model of PMN-prominent alveolitis leading to fibrosis. We examined a method of identifying the alveolitis during its PMN-prominent phase with indium 111-labeled homologous PMNs (In-PMNs). When pairs of injured and uninjured rats were compared, greater activity was consistently found persisting in the lung images of the injured rats, both several hours (early) and a day (late) after injection of In-PMNs. Differences could likewise be identified when lung activity was normalized to activity of the injectate, the spleen, and variably the liver, as determined from organ images. These differences in gamma camera images were supported by direct measurement of activity in organs obtained by killing the animals after scanning. When groups of animals were compared, lung/spleen ratios appeared to most consistently differentiate the group of normal animals from those with alveolitis. These methods may provide a noninvasive means of identifying PMN prominence in the lung, which occurs in some fibrotic processes.

  8. Preference Construction under Prominence : Hoe bepalen consumenten hun voorkeur als niet alles even belangrijk is?

    NARCIS (Netherlands)

    I. Evangelidis (Ioannis)

    2015-01-01

    markdownabstract__Abstract__ Prior academic research and common sense assume that differences in attribute importance weights should determine choice. All else equal, consumers are presumed to prefer products that in their view are superior along the products’ most important—or so-called “prominent

  9. From Wilhelm von Humboldt to Hitler-are prominent people more prone to have Parkinson's disease?

    Science.gov (United States)

    Horowski; Horowski; Calne; Calne

    2000-10-01

    We describe Parkinsonism in prominent people, where Wilhelm von Humboldt and Adolf Hitler provide just two spectacular, opposing examples. In both of them, there is little if any evidence that the disease did influence their life ambitions, methods of achieving them or cognitive function in general. Thus, Hitler's Parkinsonism should remain a 'footnote' to history, and historians should acknowledge that in his last years, his trembling, his curbed posture, his slow walking, mask-like face and low voice did not indicate remorse, fear or depression as a consequence of his crimes, but were mere expressions of his disease which, until the end, had no impact on his intellectual skills and methods. The apparently higher incidence of Parkinsonism in prominent people may be just due to their higher visibility, or a consequence of disease-related personality traits (e.g. ambition, perfectionism, rigidity) which may contribute to becoming, e.g., a prominent authoritarian person. Perhaps even some early behaviour pattern (such as repressed emotions or acting in public-which could even increase the risk of some infection) contributes to a greater vulnerability for developing Parkinsonism. Further studying other prominent cases might lead us to better understanding of risk factors and the expression of early Parkinsonism.

  10. Anxiety and Antisocial Behavior: The Moderating Role of Perceptions of Social Prominence among Incarcerated Females

    Science.gov (United States)

    Monahan, Kathryn C.; Goldweber, Aska; Meyer, Kristen; Cauffman, Elizabeth

    2012-01-01

    The present study examines how perceptions of social prominence and attitudes toward antisocial behavior among peers moderate the association between anxiety and antisocial behavior among incarcerated females. Latent profile analysis identified two classes of females distinguished by their perceptions and attitudes. Individuals in both classes…

  11. From prominence to obscurity : a study of the Darumashū : Japan's first Zen school

    NARCIS (Netherlands)

    Breugem, Vincent Michaël Nicolaas

    2012-01-01

    From Prominence to Obscurity focuses on the Darumashū (Bodhidharma school), a little known but important agent in the formative history of Zen in Japan. In the late twelfth and thirteenth centuries, the Darumashū – established by the monk Dainichi Nōnin (fl. 1189) – was considered representative of

  12. HST Observations of IP Pegasi in Quiescence The Pre-Eclipse Spectrum

    CERN Document Server

    Hoard, D W; Eracleous, M; Horne, K; Misselt, K A; Shafter, A W; Szkody, P; Wood, J H; Baptista, Raymundo; Eracleous, Michael; Horne, Keith; Shafter, Allen W.; Szkody, Paula; Wood, Janet H.

    1997-01-01

    We present time-resolved HST UV spectroscopy and ground-based optical photometry of the dwarf nova IP Peg in a quiescent state. The observations were obtained prior to an eclipse, when the bright spot caused by the impact of the accretion stream with the edge of the disk dominates the light output. The optical light curve is strongly correlated with the UV spectrophotometric flux curve. An emission-like feature near 1820 A in the UV spectrum is likely to be a manifestation of the ``Fe II curtain.'' Composite spectra constructed from the peaks and troughs of flickers in the light curve show substantial differences. The spectrum of the flickers is not adequately modelled by a simple blackbody, suggesting that a more sophisticated model is appropriate. We perform a cross-correlation analysis of the variability in spectrophotometric flux curves of the UV continuum and prominent UV emission lines (C II 1335, Si IV 1400, C IV 1550). The continuum and lines are not correlated, suggesting that they are produced separ...

  13. Fibrous dysplasia of the maxilla in an elderly female: Case report on a 14-year quiescent phase

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Do; Lee, Wan; Park, Yong Chan; Choi, Moon Ki [College of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Kim, Myong Hyoun [Dept. of Nuclear Medicine, Wonkwang University, School of Medicine and Institute of Wonkwang Medical Science, Iksan (Korea, Republic of); Yoon, Jung Hoon [Dept. of Oral and Maxillofacial Pathology, College of Dentistry, Wonkwang Bone Regeneration Research Institute, Daejeon Dental Hospital, Wonkwang University, Daejeon (Korea, Republic of)

    2016-12-15

    Fibrous dysplasia (FD) is an uncommon skeletal disorder in which normal bone is replaced by abnormal fibroosseous tissue. Mainly, FD is found in children, and by adulthood it usually becomes quiescent. Our case showed FD of more than 14-year duration in the left maxilla. Our evaluation was that growth ceased in adulthood and had achieved the static stage. Because FD cases in elderly patients are rarely reported, we hereby present a monostotic FD case in a 65-year-old female. We presented sequential radiographic images and scintigraphic images of this case, and combined them with a literature review that emphasized the progression of the disease.

  14. Fibrous dysplasia of the maxilla in an elderly female: Case report on a 14-year quiescent phase

    Science.gov (United States)

    Lee, Wan; Park, Yong-Chan; Kim, Myoung-Hyoun; Choi, Moon-Ki; Yoon, Jung-Hoon

    2016-01-01

    Fibrous dysplasia (FD) is an uncommon skeletal disorder in which normal bone is replaced by abnormal fibro-osseous tissue. Mainly, FD is found in children, and by adulthood it usually becomes quiescent. Our case showed FD of more than 14-year duration in the left maxilla. Our evaluation was that growth ceased in adulthood and had achieved the static stage. Because FD cases in elderly patients are rarely reported, we hereby present a monostotic FD case in a 65-year-old female. We presented sequential radiographic images and scintigraphic images of this case, and combined them with a literature review that emphasized the progression of the disease. PMID:28035304

  15. Dclk1 Defines Quiescent Pancreatic Progenitors that Promote Injury-Induced Regeneration and Tumorigenesis | Office of Cancer Genomics

    Science.gov (United States)

    The existence of adult pancreatic progenitor cells has been debated. While some favor the concept of facultative progenitors involved in homeostasis and repair, neither a location nor markers for such cells have been defined. Using genetic lineage tracing, we show that Doublecortin-like kinase-1 (Dclk1) labels a rare population of long-lived, quiescent pancreatic cells. In vitro, Dclk1+ cells proliferate readily and sustain pancreatic organoid growth. In vivo, Dclk1+ cells are necessary for pancreatic regeneration following injury and chronic inflammation.

  16. Discovery of a Strongly-Lensed Massive Quiescent Galaxy at z=2.636: Spatially-Resolved Spectroscopy and Indications of Rotation

    CERN Document Server

    Newman, Andrew B; Ellis, Richard S

    2015-01-01

    We report the discovery of RG1M0150, a massive, recently quenched galaxy at z=2.636 that is multiply imaged by the cluster MACSJ0150.3-1005. We derive a stellar mass of log M_*=11.49+0.10-0.16 and a half-light radius of R_e,maj =1.8+-0.4 kpc. Taking advantage of the lensing magnification, we are able to spatially resolve a remarkably massive yet compact quiescent galaxy at z>2 in ground-based near-infrared spectroscopic observations using Magellan/FIRE and Keck/MOSFIRE. We find no gradient in the strength of the Balmer absorption lines over 0.6 R_e - 1.6 R_e, which are consistent with an age of 760 Myr. Gas emission in [NII] broadly traces the spatial distribution of the stars and is coupled with weak Halpha emission (log [NII]/Halpha = 0.6+-0.2), indicating that OB stars are not the primary ionizing source. The velocity dispersion within the effective radius is sigma_e = 271+-41 km/s. We detect rotation in the stellar absorption lines for the first time beyond z~1. Using a two-integral Jeans model that accou...

  17. Pathways to quiescence: SHARDS view on the Star Formation Histories of massive quiescent galaxies at 1.0 < z < 1.5

    CERN Document Server

    Sánchez, Helena Domínguez; Esquej, Pilar; Eliche-Moral, M Carmen; Herrero, Almudena Alonso; Caballero, Antonio Hernán; Cenarro, Javier; Charlot, Stèphane; Bruzual, Gustavo

    2015-01-01

    We present Star Formation Histories (SFHs) for a sample of 104 massive (M$>$10$^{10}$ M$\\odot$) quiescent galaxies (MQGs) at $z=$1.0-1.5. The SFHs have been inferred from spectro-photometric data from the SHARDS and HST/WFC3 G102 and G141 surveys of the GOODS-N field and broad-band observations in the UV-to-FIR spectral range. The sample of MQGs is based on rest-frame $UVJ$ colors and specific star formation rates. The Spectral Energy Distributions (SEDs) of each galaxy have been compared to models assuming an exponentially declining SFH. The SED-fitting method includes a Montecarlo algorithm to characterize the degeneracies in this kind of study. Taking advantage of the SHARDS data resolution, we are able to break these degeneracies by measuring absorption indices (Mg$_{UV}$ and D4000). Most of the sample ($\\sim$85$\\%$) presents relatively young mass-weighted ages t$_M$ $1.0$, when our galaxies were 0.5--1.0~Gyr old. According to the derived SFH, all of the MQGs experienced a Luminous Infrared Galaxy (LIRG) ...

  18. Contemporaneous XMM-Newton investigation of a giant X-ray flare and quiescent state from a cool M-class dwarf in the local cavity

    CERN Document Server

    Gupta, Anjali; Williams, Benjamin

    2011-01-01

    We report the serendipitous detection of a giant X-ray flare from the source 2XMM J043527.2-144301 during an XMM-Newton observation of the high latitude molecular cloud MBM20. The source has not been previously studied at any wavelength. The X-ray flux increases by a factor of more than 52 from quiescent state to peak of flare. A 2MASS counterpart has been identified (2MASS J04352724-1443017), and near-infrared colors reveal a spectral type of M8-M8.5 and a distance of (67\\pm 13) pc, placing the source in front of MBM20. Spectral analysis and source luminosity are also consistent with this conclusion. The measured distance makes this object the most distant source (by about a factor of 4) at this spectral type detected in X-rays. The X-ray flare was characterized by peak X-ray luminosity of ~8.2E28 erg s-1 and integrated X-ray energy of ~2.3E32 erg. The flare emission has been characterized with a 2-temperature model with temperatures of ~10 and 46 MK (0.82 and 3.97 keV), and is dominated by the higher temper...

  19. Larger sizes of massive quiescent early-type galaxies in clusters than in the field at 0.8 < z < 1.5

    CERN Document Server

    Delaye, L; Mei, S; Lidman, C; Licitra, R; Newman, A; Raichoor, A; Shankar, F; Barrientos, F; Bernardi, M; Cerulo, P; Couch, W; Demarco, R; Muñoz, R; Sanchez-Janssen, R; Tanaka, M

    2013-01-01

    [abridged] The mass-size relation of early-type galaxies (ETGs) has been largely studied in the last years to probe the mass assembly of the most massive objects in the Universe. In this paper, we focus on the mass-size relation of quiescent massive ETGs (Mstar/Msol > 3*10^10) living in massive clusters (M200 ~ 10^14 Mstar) at 0.8< z <1.5, as compared to those living in the field at the same epoch. Our sample contains ~ 400 ETGs in clusters and the same number in the field. Therefore, our sample is approximately an order of magnitude larger than previous studies in the same redshift range for galaxy clusters. We find that ETGs living in clusters are between ~30-50% larger than galaxies with the same stellar mass residing in the field. We parametrize the size using the mass-normalized size, gamma=Re/Mstar^0.57. The gamma distributions in both environments peak at the same position but the distributions in clusters are more skewed towards larger sizes. Since this size difference is not observed in the loc...

  20. Multiwavelength Study of Quiescent States of Mrk 421 with Unprecedented Hard X-Ray Coverage Provided by NuSTAR in 2013

    Science.gov (United States)

    Baloković, M.; Paneque, D.; Madejski, G.; Furniss, A.; Chiang, J.; Ajello, M.; Alexander, D. M.; Barret, D.; Blandford, R. D.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Forster, K.; Giommi, P.; Grefenstette, B.; Hailey, C.; Harrison, F. A.; Hornstrup, A.; Kitaguchi, T.; Koglin, J. E.; Madsen, K. K.; Mao, P. H.; Miyasaka, H.; Mori, K.; Perri, M.; Pivovaroff, M. J.; Puccetti, S.; Rana, V.; Stern, D.; Tagliaferri, G.; Urry, C. M.; Westergaard, N. J.; Zhang, W. W.; Zoglauer, A.; NuSTAR Team; Archambault, S.; Archer, A.; Barnacka, A.; Benbow, W.; Bird, R.; Buckley, J. H.; Bugaev, V.; Cerruti, M.; Chen, X.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dickinson, H. J.; Dumm, J.; Eisch, J. D.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Fortson, L.; Griffin, S.; Griffiths, S. T.; Grube, J.; Gyuk, G.; Huetten, M.; Håkansson, N.; Holder, J.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krause, M.; Krennrich, F.; Lang, M. J.; Maier, G.; McArthur, S.; Meagher, K.; Moriarty, P.; Nelson, T.; Nieto, D.; Ong, R. A.; Park, N.; Pohl, M.; Popkow, A.; Pueschel, E.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Todd, N. W.; Tucci, J. V.; Tyler, J.; Vincent, S.; Weinstein, A.; Wilhelm, A.; Williams, D. A.; Zitzer, B.; VERITAS Collaboration; Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Chatterjee, A.; Clavero, R.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Delgado Mendez, C.; Di Pierro, F.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Elsaesser, D.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giammaria, P.; Glawion (Eisenacher, D.; Godinović, N.; González Muñoz, A.; Guberman, D.; Hahn, A.; Hanabata, Y.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Idec, W.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Majumdar, P.; Makariev, M.; Mallot, K.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Moretti, E.; Nakajima, D.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Orito, R.; Overkemping, A.; Paiano, S.; Palacio, J.; Palatiello, M.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Persic, M.; Poutanen, J.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; Saito, T.; Satalecka, K.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Stamerra, A.; Steinbring, T.; Strzys, M.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Torres, D. F.; Toyama, T.; Treves, A.; Verguilov, V.; Vovk, I.; Ward, J. E.; Will, M.; Wu, M. H.; Zanin, R.; MAGIC Collaboration; Perkins, J.; Verrecchia, F.; Leto, C.; Böttcher, M.; Villata, M.; Raiteri, C. M.; Acosta-Pulido, J. A.; Bachev, R.; Berdyugin, A.; Blinov, D. A.; Carnerero, M. I.; Chen, W. P.; Chinchilla, P.; Damljanovic, G.; Eswaraiah, C.; Grishina, T. S.; Ibryamov, S.; Jordan, B.; Jorstad, S. G.; Joshi, M.; Kopatskaya, E. N.; Kurtanidze, O. M.; Kurtanidze, S. O.; Larionova, E. G.; Larionova, L. V.; Larionov, V. M.; Latev, G.; Lin, H. C.; Marscher, A. P.; Mokrushina, A. A.; Morozova, D. A.; Nikolashvili, M. G.; Semkov, E.; Smith, P. S.; Strigachev, A.; Troitskaya, Yu. V.; Troitsky, I. S.; Vince, O.; Barnes, J.; Güver, T.; Moody, J. W.; Sadun, A. C.; Sun, S.; Hovatta, T.; Richards, J. L.; Max-Moerbeck, W.; Readhead, A. C. R.; Lähteenmäki, A.; Tornikoski, M.; Tammi, J.; Ramakrishnan, V.; Reinthal, R.; Angelakis, E.; Fuhrmann, L.; Myserlis, I.; Karamanavis, V.; Sievers, A.; Ungerechts, H.; Zensus, J. A.

    2016-03-01

    We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from radio to very high energy (VHE) γ-ray bands. NuSTAR yielded previously unattainable sensitivity in the 3-79 keV range, revealing that the spectrum softens when the source is dimmer until the X-ray spectral shape saturates into a steep {{Γ }}≈ 3 power law, with no evidence for an exponential cutoff or additional hard components up to ˜80 keV. For the first time, we observed both the synchrotron and the inverse-Compton peaks of the spectral energy distribution (SED) simultaneously shifted to frequencies below the typical quiescent state by an order of magnitude. The fractional variability as a function of photon energy shows a double-bump structure that relates to the two bumps of the broadband SED. In each bump, the variability increases with energy, which, in the framework of the synchrotron self-Compton model, implies that the electrons with higher energies are more variable. The measured multi band variability, the significant X-ray-to-VHE correlation down to some of the lowest fluxes ever observed in both bands, the lack of correlation between optical/UV and X-ray flux, the low degree of polarization and its significant (random) variations, the short estimated electron cooling time, and the significantly longer variability timescale observed in the NuSTAR light curves point toward in situ electron acceleration and suggest that there are multiple compact regions contributing to the broadband emission of Mrk 421 during low-activity states.

  1. Mid-Infrared Observations of Normal Star-Forming Galaxies The Infrared Space Observatory Key Project Sample

    CERN Document Server

    Dale, D A; Helou, G; Dale, Daniel A.; Silbermann, Nancy A.; Helou, George

    2000-01-01

    We present mid-infrared maps and preliminary analysis for 61 galaxies observed with the ISOCAM instrument aboard the Infrared Space Observatory. Many of the general features of galaxies observed at optical wavelengths---spiral arms, disks, rings, and bright knots of emission---are also seen in the mid-infrared, except the prominent optical bulges are absent at 6.75 and 15 microns. In addition, the maps are quite similar at 6.75 and 15 microns, except for a few cases where a central starburst leads to lower 6.75/15 ratios in the inner region. We also present infrared flux densities and mid-infrared sizes for these galaxies. The mid-infrared color 6.75/15 shows a distinct trend with the far-infrared color 60/100. The quiescent galaxies in our sample (60/100 < 0.6) show 6.75/15 near unity, whereas this ratio drops significantly for galaxies with higher global heating intensity levels. Azimuthally-averaged surface brightness profiles indicate the extent to which the mid-infrared flux is centrally concentrated,...

  2. Indications of stellar prominence oscillations on fast rotating stars: the cases of HK Aqr and PZ Tel

    Science.gov (United States)

    Leitzinger, M.; Odert, P.; Zaqarashvili, T. V.; Greimel, R.; Hanslmeier, A.; Lammer, H.

    2016-11-01

    We present the analysis of six nights of spectroscopic monitoring of two young and fast rotating late-type stars, namely the dMe star HK Aqr and the dG/dK star PZ Tel. On both stars, we detect absorption features reminiscent of signatures of corotating cool clouds or prominences visible in Hα. Several prominences on HK Aqr show periodic variability in the prominence tracks which follow a sinusoidal motion (indication of prominence oscillations). On PZ Tel, we could not find any periodic variability in the prominence tracks. By fitting sinusoidal functions to the prominence tracks, we derive amplitudes and periods which are similar to those of large-amplitude oscillations seen in solar prominences. In one specific event, we also derive a periodic variation of the prominence track in the Hβ spectral line which shows an anti-phase variation with the one derived for the Hα spectral line. Using these parameters and estimated mass density of a prominence on HK Aqr, we derive a minimum magnetic field strength of ˜2 G. The relatively low strength of the magnetic field is explained by the large height of this stellar prominence (≥ 0.67 stellar radii above the surface).

  3. Gene expression changes in diapause or quiescent potato cyst nematode, Globodera pallida, eggs after hydration or exposure to tomato root diffusate

    Directory of Open Access Journals (Sweden)

    Juan Emilio Palomares-Rius

    2016-02-01

    Full Text Available Plant-parasitic nematodes (PPN need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest including hatching inhibition and dauer stages are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN (Globodera pallida and G. rostochiensis are frequently in an anhydrobiotic state, with unhatched nematode persisting for extended periods of time inside the cyst in the absence of the host. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G. pallida to hydration and following exposure to tomato root diffusate (RD using microarray gene expression analysis encompassing a broad set of genes. For the quiescent eggs, 547 genes showed differential expression following hydration vs. hydratation and RD (H-RD treatment whereas 708 genes showed differential regulation for the diapaused eggs following these treatments. The comparison between hydrated quiescent and diapaused eggs showed marked differences, with 2,380 genes that were differentially regulated compared with 987 genes following H-RD. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long-term survival. Transport activity is highly up-regulated following H-RD and few genes were coincident between both kinds of eggs. With the quiescent eggs, the majority of genes were related to ion transport (mainly sodium, while the diapaused eggs showed a major diversity of transporters (amino acid transport, ion transport, acetylcholine or other molecules.

  4. Trace metal suites in Antarctic pre-industrial ice are consistent with emissions from quiescent degassing of volcanoes worldwide

    Science.gov (United States)

    Matsumoto, A.; Hinkley, T.K.

    2001-01-01

    Trace metals are more abundant in atmospheric load and deposition material than can be due to rock and soil dusts and ocean salt. In pre-industrial ice from coastal west Antarctica, dust and salt account for only a few percent of the lead, cadmium, and indium that is present in most samples, less than half in any sample. For these trace metals, the deposition rate to the pre-industrial ice is approximately matched by the output rate to the atmosphere by quiescent (non-explosive) degassing of volcanoes worldwide, according to a new estimate. The basis of the match is the masses and proportions of the metals, and the proportions of Pb isotopes, in ice and in volcano emissions. The isotopic compositions of Pb in ice are similar to those of a suite of ocean island volcanoes, mostly in the southern hemisphere. The natural baseline values for pre-industrial atmospheric deposition fluxes of trace metal suites at Taylor Dome, and the worldwide quiescent volcano emissions fluxes to which they are linked, constitute a reasonably well-constrained baseline component for deposition fluxes of metals in modern times. ?? 2001 Elsevier Science B.V. All rights reserved.

  5. Emission geometry, radiation pattern, and magnetic topology of the magnetar XTE J1810-197 in its quiescent state

    CERN Document Server

    Bernardini, Federico; Gotthelf, Eric; Israel, Gian Luca; Rea, Nanda; Stella, Luigi

    2011-01-01

    The return to the quiescent state of the Anomalous X-ray pulsar XTE J1810-197 following its 2003 outburst represents a unique opportunity to probe the surface emission properties of a magnetar. The quiescent emission of XTE J1810-197 is composed of two thermal components, one arising from the whole star surface, and the other from a small warm spot on it. By modeling the magnitude and shape of the pulse profile in narrow spectral bands, we have been able to constrain the physical characteristics and geometrical parameters of the system: the two angles that the line of sight and the spin axis make with respect to the warm spot axis (\\psi\\ and \\xi\\ respectively), the angular size of the spot, and the overall surface temperature distribution. Our modeling accounts for the general relativistic effects of gravitational redshift and light bending near the stellar surface, and allows for local anisotropic emission. We found that the surface temperature distribution on the neutron star is consistent with the expectat...

  6. Glucose Regulates Cyclin D2 Expression in Quiescent and Replicating Pancreatic β-Cells Through Glycolysis and Calcium Channels

    Science.gov (United States)

    Salpeter, Seth J.; Klochendler, Agnes; Weinberg-Corem, Noa; Porat, Shay; Granot, Zvi; Shapiro, A. M. James; Magnuson, Mark A.; Eden, Amir; Grimsby, Joseph; Glaser, Benjamin

    2011-01-01

    Understanding the molecular triggers of pancreatic β-cell proliferation may facilitate the development of regenerative therapies for diabetes. Genetic studies have demonstrated an important role for cyclin D2 in β-cell proliferation and mass homeostasis, but its specific function in β-cell division and mechanism of regulation remain unclear. Here, we report that cyclin D2 is present at high levels in the nucleus of quiescent β-cells in vivo. The major regulator of cyclin D2 expression is glucose, acting via glycolysis and calcium channels in the β-cell to control cyclin D2 mRNA levels. Furthermore, cyclin D2 mRNA is down-regulated during S-G2-M phases of each β-cell division, via a mechanism that is also affected by glucose metabolism. Thus, glucose metabolism maintains high levels of nuclear cyclin D2 in quiescent β-cells and modulates the down-regulation of cyclin D2 in replicating β-cells. These data challenge the standard model for regulation of cyclin D2 during the cell division cycle and suggest cyclin D2 as a molecular link between glucose levels and β-cell replication. PMID:21521747

  7. A Nuclear Role for miR-9 and Argonaute Proteins in Balancing Quiescent and Activated Neural Stem Cell States

    Directory of Open Access Journals (Sweden)

    Shauna Katz

    2016-10-01

    Full Text Available Throughout life, adult neural stem cells (NSCs produce new neurons and glia that contribute to crucial brain functions. Quiescence is an essential protective feature of adult NSCs; however, the establishment and maintenance of this state remain poorly understood. We demonstrate that in the adult zebrafish pallium, the brain-enriched miR-9 is expressed exclusively in a subset of quiescent NSCs, highlighting a heterogeneity within these cells, and is necessary to maintain NSC quiescence. Strikingly, miR-9, along with Argonaute proteins (Agos, is localized to the nucleus of quiescent NSCs, and manipulating their nuclear/cytoplasmic ratio impacts quiescence. Mechanistically, miR-9 permits efficient Notch signaling to promote quiescence, and we identify the RISC protein TNRC6 as a mediator of miR-9/Agos nuclear localization in vivo. We propose a conserved non-canonical role for nuclear miR-9/Agos in controlling the balance between NSC quiescence and activation, a key step in maintaining adult germinal pools.

  8. MOSFIRE Spectroscopy of Quiescent Galaxies at 1.5 < z < 2.5. I - Evolution of Structural and Dynamical Properties

    CERN Document Server

    Belli, Sirio; Ellis, Richard S

    2016-01-01

    We present deep near-infrared spectra for a sample of 24 quiescent galaxies in the redshift range 1.5 < z < 2.5 obtained with the MOSFIRE spectrograph at the W. M. Keck Observatory. In conjunction with a similar dataset we obtained in the range 1 < z < 1.5 with the LRIS spectrograph, we analyze the kinematic and structural properties for 80 quiescent galaxies, the largest homogeneously-selected sample to date spanning 3 Gyr of early cosmic history. Analysis of our Keck spectra together with measurements derived from associated HST images reveals increasingly larger stellar velocity dispersions and smaller sizes to redshifts beyond z~2. By classifying our sample according to Sersic indices, we find that among disk-like systems the flatter ones show a higher dynamical to stellar mass ratio compared to their rounder counterparts which we interpret as evidence for a significant contribution of rotational motion. For this subset of disk-like systems, we estimate that V/sigma, the ratio of the circular ...

  9. Quiescent-phase evolution of a surge-type glacier: Black Rapids Glacier, Alaska, U.S.A.

    Science.gov (United States)

    Heinrichs, T.A.; Mayo, L.R.; Echelmeyer, K.A.; Harrison, W.D.

    1996-01-01

    Black Rapids Glacier, a surge-type glacier in the Alaska Range, most recently surged in 1936-37 and is currently in its quiescent phase. Mass balance, ice velocity and thickness change have been measured at three to ten sites from 1972 to 1994. The annual speed has undergone cyclical fluctuations of as much as 45% about the mean speed. Ice thickness and surface slope did not change enough to cause the speed fluctuations through changes in ice deformation, which indicates that they are being driven by changes in basal motion. The behavior of Black Rapids Glacier during this quiescent phase is significantly different from that of Variegated Glacier, another well-studied surge-type glacier in Alaska. The present medial-moraine configuration of Black Rapids Glacier indicates that a surge could occur at any time. However, ice velocity data indicate that the next surge may not be imminent. We believe that there is little chance that the next surge will cross and dam the Delta River.

  10. The spatial damping of magnetohydrodynamic waves in a flowing partially ionised prominence plasma

    CERN Document Server

    Carbonell, M; Oliver, R; Ballester, J L

    2010-01-01

    Solar prominences are partially ionised plasmas displaying flows and oscillations. These oscillations show time and spatial damping and, commonly, have been explained in terms of magnetohydrodynamic (MHD) waves. We study the spatial damping of linear non-adiabatic MHD waves in a flowing partially ionised plasma, having prominence-like physical properties. We consider single fluid equations for a partially ionised hydrogen plasma including in the energy equation optically thin radiation, thermal conduction by electrons and neutrals, and heating. Keeping the frequency real and fixed, we have solved the obtained dispersion relations for the complex wavenumber, k, and have analysed the behaviour of the damping length, wavelength and the ratio of the damping length to the wavelength, versus period, for Alfven, fast, slow and thermal waves.

  11. F0-based rhythm effects on the perception of local syllable prominence

    DEFF Research Database (Denmark)

    Niebuhr, Oliver

    2009-01-01

    A perception experiment shows for German that different global, F(0)-based speech rhythms in the context section of stimuli influence the local prominence position in the target section. This effect may be conceptualized as a perceptual adjustment of the syllables in the target section to the ones...... of the global rhythmic context with regard to both the prominence and the F(0) patterns. Two conclusions were drawn on this basis. First, listeners use speech rhythm to predict the perceptual properties of syllables, which is in line with the guide function that speech rhythm is assumed to have in German...... and other Western Germanic languages. Secondly, speech rhythm is a perceptual phenomenon, generated by a cyclic construction process that involves repetitive patterns in multiple dimensions. Thus, although speech rhythm is initiated by changes in acoustic parameters, it cannot be soaked up by acoustic...

  12. Topographic prominence discriminator for the detection of short-latency spikes of retinal ganglion cells

    Science.gov (United States)

    Choi, Myoung-Hwan; Ahn, Jungryul; Park, Dae Jin; Lee, Sang Min; Kim, Kwangsoo; Cho, Dong-il Dan; Senok, Solomon S.; Koo, Kyo-in; Goo, Yong Sook

    2017-02-01

    Objective. Direct stimulation of retinal ganglion cells in degenerate retinas by implanting epi-retinal prostheses is a recognized strategy for restoration of visual perception in patients with retinitis pigmentosa or age-related macular degeneration. Elucidating the best stimulus-response paradigms in the laboratory using multielectrode arrays (MEA) is complicated by the fact that the short-latency spikes (within 10 ms) elicited by direct retinal ganglion cell (RGC) stimulation are obscured by the stimulus artifact which is generated by the electrical stimulator. Approach. We developed an artifact subtraction algorithm based on topographic prominence discrimination, wherein the duration of prominences within the stimulus artifact is used as a strategy for identifying the artifact for subtraction and clarifying the obfuscated spikes which are then quantified using standard thresholding. Main results. We found that the prominence discrimination based filters perform creditably in simulation conditions by successfully isolating randomly inserted spikes in the presence of simple and even complex residual artifacts. We also show that the algorithm successfully isolated short-latency spikes in an MEA-based recording from degenerate mouse retinas, where the amplitude and frequency characteristics of the stimulus artifact vary according to the distance of the recording electrode from the stimulating electrode. By ROC analysis of false positive and false negative first spike detection rates in a dataset of one hundred and eight RGCs from four retinal patches, we found that the performance of our algorithm is comparable to that of a generally-used artifact subtraction filter algorithm which uses a strategy of local polynomial approximation (SALPA). Significance. We conclude that the application of topographic prominence discrimination is a valid and useful method for subtraction of stimulation artifacts with variable amplitudes and shapes. We propose that our algorithm

  13. The challenges to the consolidation of Brazil’s international prominence: education and culture

    Directory of Open Access Journals (Sweden)

    Elizabete Sanches Rocha

    2012-04-01

    Full Text Available Over the last years, Brazil has gained international visibility especially due to the capacity of its economical development and the progress of its public policies on fighting poverty. Though there reason for celebration exists with respect to the country’s recent achievements, Brazil still has a lot to do if it wants to gain international prominence. In this paper, we address two issues that are fundamental for Brazil to achieve real leadership: education and culture.

  14. Near-fault ground motions with prominent acceleration pulses: pulse characteristics and ductility demand

    Institute of Scientific and Technical Information of China (English)

    Mai Tong; Vladimir Rzhevsky; Dai Junwu; George C Lee; Qi Jincheng; Qi Xiaozhai

    2007-01-01

    Major earthquakes of last 15 years (e.g., Northridge 1994, Kobe 1995 and Chi-Chi 1999) have shown that many near-fault ground motions possess prominent acceleration pulses. Some of the prominent ground acceleration pulses are related to large ground velocity pulses, others are caused by mechanisms that are totally different from those causing the velocity pulses or fling steps. Various efforts to model acceleration pulses have been reported in the literature. In this paper, research results from a recent study of acceleration pulse prominent ground motions and an analysis of structural damage induced by acceleration pulses are summarized. The main results of the study include: (1) temporal characteristics of acceleration pulses; (2) ductility demand spectrum of simple acceleration pulses with respect to equivalent classes of dynamic systems and pulse characteristic parameters; and (3) estimation of fundamental period change under the excitation of strong acceleration pulses. By using the acceleration pulse induced linear acceleration spectrum and the ductility demand spectrum,a simple procedure has been developed to estimate the ductility demand and the fundamental period change of a reinforced concrete (RC) structure under the impact of a strong acceleration pulse.

  15. Physical aggression, spreading of rumors, and social prominence in early adolescence: reciprocal effects supporting gender similarities?

    Science.gov (United States)

    Juvonen, Jaana; Wang, Yueyan; Espinoza, Guadalupe

    2013-12-01

    There is a robust association between aggression and social prominence by early adolescence, yet findings regarding the direction of influence remain inconclusive in light of gender differences across various forms of aggressive behaviors. The current study examined whether physical aggression and spreading of rumors, as two gender-typed aggressive behaviors that differ in overt displays of power, promote and/or maintain socially prominent status for girls and boys during non-transitional grades in middle school. Peer nominations were used to assess physical aggression, spreading of rumors, and "cool" reputation (social prominence) during three time points between the spring of seventh grade and spring of eighth grade. Participants included 1,895 (54 % female) ethnically diverse youth: 47 % Latino, 22 % African-American, 11 % Asian, 10 % White and 10 % Other/Mixed ethnic background. Cross-lagged path analyses were conducted to test the directionality of the effects, and gender moderation was assessed by relying on multi-group analyses. The analyses revealed mainly reciprocal associations for each form of aggression, suggesting that boys, as well as girls, can both gain and maintain their status by spreading rumors about their peers, just as they do by physically fighting and pushing others in urban middle schools. The implications of the findings for interventions are discussed.