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Sample records for post double common-envelope

  1. Testing Common Envelopes on Double White Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Nandez, Jose L. A.; Ivanova, Natalia; Lombardi, James C., Jr.

    2015-06-01

    The formation of a double white dwarf binary likely involves a common envelope (CE) event between a red giant and a white dwarf (WD) during the most recent episode of Roche lobe overflow mass transfer. We study the role of recombination energy with hydrodynamic simulations of such stellar interactions. We find that the recombination energy helps to expel the common envelope entirely, while if recombination energy is not taken into account, a significant fraction of the common envelope remains bound. We apply our numerical methods to constrain the progenitor system for WD 1101+364 - a double WD binary that has well-measured mass ratio of q=0.87±0.03 and an orbital period of 0.145 days. Our best-fit progenitor for the pre-common envelope donor is a 1.5 ⊙ red giant.

  2. Orbital period variations in eclipsing post-common-envelope binaries

    NASA Astrophysics Data System (ADS)

    Parsons, S. G.; Marsh, T. R.; Copperwheat, C. M.; Dhillon, V. S.; Littlefair, S. P.; Hickman, R. D. G.; Maxted, P. F. L.; Gänsicke, B. T.; Unda-Sanzana, E.; Colque, J. P.; Barraza, N.; Sánchez, N.; Monard, L. A. G.

    2010-10-01

    We present high-speed ULTRACAM photometry of the eclipsing post-common-envelope binaries DE CVn, GK Vir, NN Ser, QS Vir, RR Cae, RX J2130.6+4710, SDSS 0110+1326 and SDSS 0303+0054 and use these data to measure precise mid-eclipse times in order to detect any period variations. We detect a large (~250 s) departure from linearity in the eclipse times of QS Vir which Applegate's mechanism fails to reproduce by an order of magnitude. The only mechanism able to drive this period change is a third body in a highly elliptical orbit. However, the planetary/sub-stellar companion previously suggested to exist in this system is ruled out by our data. Our eclipse times show that the period decrease detected in NN Ser is continuing, with magnetic braking or a third body the only mechanisms able to explain this change. The planetary/sub-stellar companion previously suggested to exist in NN Ser is also ruled out by our data. Our precise eclipse times also lead to improved ephemerides for DE CVn and GK Vir. The width of a primary eclipse is directly related to the size of the secondary star and variations in the size of this star could be an indication of Applegate's mechanism or Wilson (starspot) depressions which can cause jitter in the O-C curves. We measure the width of primary eclipses for the systems NN Ser and GK Vir over several years but find no definitive variations in the radii of the secondary stars. However, our data are precise enough (Δ Rsec/Rsec < 10-5) to show the effects of Applegate's mechanism in the future. We find no evidence of Wilson depressions in either system. We also find tentative indications that flaring rates of the secondary stars depend on their mass rather than rotation rates.

  3. Coronal Element Abundances of the Post-Common Envelope Binary V471 Tauri with ASCA

    NASA Technical Reports Server (NTRS)

    Still, Martin; Hussain, Gaitee; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We report on ASCA observations of the coronally active companion star in the post-common envelope binary V471 Tau. While it would be prudent to check the following results with grating spectroscopy, we find that a single-temperature plasma model does not fit the data. Two temperature models with variable abundances indicate that Fe is underabundant compared to the Hyades photospheric mean, whereas, the high first ionization potential element Ne is overabundant. This is indicative of the inverse first ionization effect, believed to result from the fractionation of ionized material by the magnetic field in the upper atmosphere of the star. Evolutionary calculations indicate that there should be no peculiar abundances on the companion star resulting from the common envelope epoch. Indeed, we find no evidence for peculiar abundances, although uncertainties are high.

  4. Hα Emission in Post-Common-Envelope Binaries: White Dwarf Illumination vs. Chromospheric Activity

    NASA Astrophysics Data System (ADS)

    Spiewak, Renée; Pomerantz, B.; Strelnitski, V.; Walker, G. E.; Krajci, T.

    2013-01-01

    We revisit and augment the narrow-band photometry of two post-common-envelope close binary systems, V471 Tau and DE CVn, composed of a white dwarf (WD) and a red dwarf (RD). The photometry was accomplished using the 24-inch telescope of the Maria Mitchell Observatory and the 0.35-m telescope of the Astrokolkhoz Observatory. The filters allowed us to separate the temporal behavior of the Hα emission and the adjacent continuum. The latter shows in both binaries the well-known double wave with maxima around phases 0.25 and 0.75 and with an amplitude of several percent, which has been ascribed to the ellipsoidal shape of the red dwarf. We confirm our previous, preliminary conclusion that the phase curves of Hα emission in these two stars are different: in DE CVn, it is similar to the two-peak curve of the continuum, whereas in V471 Tau it has only one maximum - at phase 0.5. We interpret this difference by the difference in the WD temperature, previously determined as 34,500 and 8,000 K, for V471 Tau and DE CVn respectively. We show that the sub-WD area of the RD in V471 Tau intercepts enough ionizing photons from the hot WD to produce the observed Hα luminosity, whereas the relatively cold WD in DE CVn lacks several orders of magnitude in UV luminosity to create the observed Hα luminosity, which therefore should be ascribed to the chromospheric activity of the RD. This project was supported by NSF/REU grant AST-0851892 and the Nantucket Maria Mitchell Association.

  5. The post-common envelope central stars of the planetary nebulae Henize 2-155 and Henize 2-161

    NASA Astrophysics Data System (ADS)

    Jones, D.; Boffin, H. M. J.; Rodríguez-Gil, P.; Wesson, R.; Corradi, R. L. M.; Miszalski, B.; Mohamed, S.

    2015-08-01

    We present a study of Hen 2-155 and Hen 2-161, two planetary nebulae which bear striking morphological similarities to other planetary nebulae known to host close-binary central stars. Both central stars are revealed to be photometric variables while spectroscopic observations confirm that Hen 2-155 is host to a double-eclipsing, post-common-envelope system with an orbital period of 3h33m making it one of the shortest period binary central stars known. The observations of Hen 2-161 are found to be consistent with a post-common-envelope binary of period ~1 day. A detailed model of the central star of Hen 2-155 is produced, showing the nebular progenitor to be a hot, post-AGB remnant of approximately 0.62 M⊙, consistent with the age of the nebula, and the secondary star to be an M dwarf whose radius is almost twice the expected zero age main sequence radius for its mass. In spite of the small numbers, all main-sequence companions, of planetary nebulae central stars, to have had their masses and radii constrained by both photometric and spectroscopic observations have also been found to display this "inflation". The cause of the "inflation" is uncertain but is probably related to rapid accretion, immediately before the recent common-envelope phase, to which the star has not yet thermally adjusted. The chemical composition of both nebulae is also analysed, showing both to display elevated abundance discrepancy factors. This strengthens the link between elevated abundance discrepancy factors and close binarity in the nebular progenitor. Full Tables 2-5, and 7 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A19

  6. Origin of apparent period variations in eclipsing post-common-envelope binaries

    NASA Astrophysics Data System (ADS)

    Zorotovic, M.; Schreiber, M. R.

    2013-01-01

    Context. Apparent period variations detected in several eclipsing, close-compact binaries are frequently interpreted as being caused by circumbinary giant planets. This interpretation raises the question of the origin of the potential planets that must have either formed in the primordial circumbinary disk, together with the host binary star, and survived its evolution into a close-compact binary or formed in a post-common-envelope circumbinary disk that remained bound to the post-common-envelope binary (PCEB). Aims: Here we combine current knowledge of planet formation and the statistics of giant planets around primordial and evolved binary stars with the theory of close-compact binary star evolution aiming to derive new constraints on possible formation scenarios. Methods: We compiled a comprehensive list of observed eclipsing PCEBs, estimated the fraction of systems showing apparent period variations, reconstructed the evolutionary history of the PCEBs, and performed binary population models of PCEBs to characterize their main sequence binary progenitors. We reviewed the currently available constraints on the fraction of PCEB progenitors that host circumbinary giant planets. Results: We find that the progenitors of PCEBs are very unlikely to be frequent hosts of giant planets (≲10 per cent), while the frequency of PCEBs with observed apparent period variations is very high (~90 per cent). Conclusions: The variations in eclipse timings measured in eclipsing PCEBs are probably not caused by first-generation planets that survived common-envelope evolution. The remaining options for explaining the observed period variations are second-generation planet formation or perhaps variations in the shape of a magnetically active secondary star. We suggest observational tests for both options. Appendix A is available in electronic form at http://www.aanda.org

  7. DOUBLE COMPACT OBJECTS. I. THE SIGNIFICANCE OF THE COMMON ENVELOPE ON MERGER RATES

    SciTech Connect

    Dominik, Michal; Belczynski, Krzysztof; Bulik, Tomasz; Fryer, Christopher; Holz, Daniel E.; Berti, Emanuele; Mandel, Ilya; O'Shaughnessy, Richard

    2012-11-01

    The last decade of observational and theoretical developments in stellar and binary evolution provides an opportunity to incorporate major improvements to the predictions from population synthesis models. We compute the Galactic merger rates for NS-NS, BH-NS, and BH-BH mergers with the StarTrack code. The most important revisions include updated wind mass-loss rates (allowing for stellar-mass black holes up to 80 M {sub Sun }), a realistic treatment of the common envelope phase (a process that can affect merger rates by 2-3 orders of magnitude), and a qualitatively new neutron star/black hole mass distribution (consistent with the observed {sup m}ass gap{sup )}. Our findings include the following. (1) The binding energy of the envelope plays a pivotal role in determining whether a binary merges within a Hubble time. (2) Our description of natal kicks from supernovae plays an important role, especially for the formation of BH-BH systems. (3) The masses of BH-BH systems can be substantially increased in the case of low metallicities or weak winds. (4) Certain combinations of parameters underpredict the Galactic NS-NS merger rate and can be ruled out. (5) Models incorporating delayed supernovae do not agree with the observed NS/BH 'mass gap', in accordance with our previous work. This is the first in a series of three papers. The second paper will study the merger rates of double compact objects as a function of redshift, star formation rate, and metallicity. In the third paper, we will present the detection rates for gravitational-wave observatories, using up-to-date signal waveforms and sensitivity curves.

  8. The crowded magnetosphere of the post-common-envelope binary QS Virginis

    NASA Astrophysics Data System (ADS)

    Parsons, S. G.; Hill, C. A.; Marsh, T. R.; Gänsicke, B. T.; Watson, C. A.; Steeghs, D.; Dhillon, V. S.; Littlefair, S. P.; Copperwheat, C. M.; Schreiber, M. R.; Zorotovic, M.

    2016-05-01

    We present high-speed photometry and high-resolution spectroscopy of the eclipsing post-common-envelope binary QS Virginis (QS Vir). Our Ultraviolet and Visual Echelle Spectrograph (UVES) spectra span multiple orbits over more than a year and reveal the presence of several large prominences passing in front of both the M star and its white dwarf companion, allowing us to triangulate their positions. Despite showing small variations on a time-scale of days, they persist for more than a year and may last decades. One large prominence extends almost three stellar radii from the M star. Roche tomography reveals that the M star is heavily spotted and that these spots are long-lived and in relatively fixed locations, preferentially found on the hemisphere facing the white dwarf. We also determine precise binary and physical parameters for the system. We find that the 14 220 ± 350 K white dwarf is relatively massive, 0.782 ± 0.013 M⊙, and has a radius of 0.010 68 ± 0.000 07 R⊙, consistent with evolutionary models. The tidally distorted M star has a mass of 0.382 ± 0.006 M⊙ and a radius of 0.381 ± 0.003 R⊙, also consistent with evolutionary models. We find that the magnesium absorption line from the white dwarf is broader than expected. This could be due to rotation (implying a spin period of only ˜700 s), or due to a weak (˜100 kG) magnetic field, we favour the latter interpretation. Since the M star's radius is still within its Roche lobe and there is no evidence that it is overinflated, we conclude that QS Vir is most likely a pre-cataclysmic binary just about to become semidetached.

  9. CHARACTERIZING THE COOL KOIs. V. KOI-256: A MUTUALLY ECLIPSING POST-COMMON ENVELOPE BINARY

    SciTech Connect

    Muirhead, Philip S.; Shporer, Avi; Becker, Juliette; Swift, Jonathan J.; Hinkley, Sasha; Pineda, J. Sebastian; Bottom, Michael; Baranec, Christoph; Riddle, Reed; Tendulkar, Shriharsh P.; Bui, Khanh; Vanderburg, Andrew; Lloyd, James P.; Fuller, Jim; Zhao, Ming; Howard, Andrew W.; Von Braun, Kaspar; Boyajian, Tabetha S.; Law, Nicholas; Ramaprakash, A. N.; and others

    2013-04-20

    We report that Kepler Object of Interest 256 (KOI-256) is a mutually eclipsing post-common envelope binary (ePCEB), consisting of a cool white dwarf (M{sub *} = 0.592 {+-} 0.089 M{sub Sun }, R{sub *} = 0.01345 {+-} 0.00091 R{sub Sun }, T{sub eff} = 7100 {+-} 700 K) and an active M3 dwarf (M{sub *} = 0.51 {+-} 0.16 M{sub Sun }, R{sub *} = 0.540 {+-} 0.014 R{sub Sun }, T{sub eff} = 3450 {+-} 50 K) with an orbital period of 1.37865 {+-} 0.00001 days. KOI-256 is listed as hosting a transiting planet-candidate by Borucki et al. and Batalha et al.; here we report that the planet-candidate transit signal is in fact the occultation of a white dwarf as it passes behind the M dwarf. We combine publicly-available long- and short-cadence Kepler light curves with ground-based measurements to robustly determine the system parameters. The occultation events are readily apparent in the Kepler light curve, as is spin-orbit synchronization of the M dwarf, and we detect the transit of the white dwarf in front of the M dwarf halfway between the occultation events. The size of the white dwarf with respect to the Einstein ring during transit (R{sub Ein} = 0.00473 {+-} 0.00055 R{sub Sun }) causes the transit depth to be shallower than expected from pure geometry due to gravitational lensing. KOI-256 is an old, long-period ePCEB and serves as a benchmark object for studying the evolution of binary star systems as well as white dwarfs themselves, thanks largely to the availability of near-continuous, ultra-precise Kepler photometry.

  10. TWO POSSIBLE CIRCUMBINARY PLANETS IN THE ECLIPSING POST-COMMON ENVELOPE SYSTEM NSVS 14256825

    SciTech Connect

    Almeida, L. A.; Jablonski, F.; Rodrigues, C. V.

    2013-03-20

    We present an analysis of eclipse timings of the post-common envelope binary NSVS 14256825, which is composed of an sdOB star and a dM star in a close orbit (P{sub orb} = 0.110374 days). High-speed photometry of this system was performed between 2010 July and 2012 August. Ten new mid-eclipse times were analyzed together with all available eclipse times in the literature. We revisited the (O - C) diagram using a linear ephemeris and verified a clear orbital period variation. On the assumption that these orbital period variations are caused by light travel time effects, the (O - C) diagram can be explained by the presence of two circumbinary bodies, even though this explanation requires a longer baseline of observations to be fully tested. The orbital periods of the best solution would be P{sub c} {approx} 3.5 years and P{sub d} {approx} 6.9 years. The corresponding projected semi-major axes would be a{sub c} sin i{sub c} {approx} 1.9 AU and a{sub d} sin i{sub d} {approx} 2.9 AU. The masses of the external bodies would be M{sub c} {approx} 2.9 M{sub Jupiter} and M{sub d} {approx} 8.1 M{sub Jupiter}, if we assume their orbits are coplanar with the close binary. Therefore NSVS 14256825 might be composed of a close binary with two circumbinary planets, though the orbital period variations is still open to other interpretations.

  11. Structure and Evolution of a Common Envelope in Simulations of Mass Transfer in Double White Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Motl, Patrick M.

    2009-01-01

    We present evolutions of mass transfer in double white dwarf binaries with several different initial mass ratios. The systems have all been evolved in two limiting cases. In the polytropic evolutions, we in essence assume that the irreversible gain in entropy at the accretion shock is radiated away. In the second regime, the fluid is treated as an ideal gas and retains all of the thermal energy gained at the accretion shock. The later case is obviously more favorable to forming a common envelope about both the donor and accretor. In reality, at least some of the energy can escape and thus the ideal gas case will probably over-emphasize the tendency to form a common envelope. The simulations evolve an ideal fluid with an Eulerian hydrodynamics code. We simultaneously solve Poisson's equation for the gravitational potential. In this poster, we report on the thermal structure of the accreted material and also on the potentially interesting loss of mass and angular momentum from the binary system.

  12. Post common envelope binaries from SDSS. XI. The white dwarf mass distributions of CVs and pre-CVs

    NASA Astrophysics Data System (ADS)

    Zorotovic, M.; Schreiber, M. R.; Gänsicke, B. T.

    2011-12-01

    Context. We have known for a long time that many of the measured white dwarf (WD) masses in cataclysmic variables (CVs) significantly exceed the mean mass of single WDs. This was thought to be related to observational biases, but recent high-precision measurements of WD masses in a great number of CVs are challenging this interpretation. A crucial question in this context is whether the high WD masses seen among CVs are already imprinted in the mass distribution of their progenitors, i.e. among detached post-common-envelope binaries (PCEBs) that consist of a WD and a main-sequence star. Aims: We review the measured WD masses of CVs, determine the WD-mass distribution of an extensive sample of PCEBs that are representative for the progenitors of the current CV population (pre-CVs) and compare both distributions. Methods: We calculate the CV formation time of the PCEBs in our sample by determining the post common-envelope (CE) and the main-sequence evolution of the binary systems and define a pre-CV to be a PCEB that evolves into a semi-detached configuration with stable mass transfer within less than the age of the Galaxy. Possible observational biases affecting the WD-mass distribution for the pre-CV and the CV samples are discussed. Results: The mean WD mass among CVs is ⟨ Mwd ⟩ = 0.83 ± 0.23 M⊙, much larger than that found for pre-CVs, ⟨ Mwd ⟩ = 0.67 ± 0.21 M⊙. Selection effects cannot explain the high WD masses observed in CVs. We also note that compared to the predictions of binary-population models, the observed fraction of He-core WDs is small both among CVs (≤10%) and pre-CVs (≤17 ± 8%). Conclusions: We suggest two possible explanations for the high WD masses among CVs, both of which imply substantial revisions to the standard model of CV evolution: either most CVs have formed above the orbital-period gap (which requires a high WD mass to initiate stable mass transfer or a previous phase of thermal-timescale mass transfer), or the mass of

  13. Monte Carlo Simulations of the Post-Common-Envelope White-Dwarf Main-Sequence Binary Population

    SciTech Connect

    Camacho, Judit; Torres, Santiago; Garcia-Berro, Enrique; Schreiber, Matthias R.

    2010-12-22

    We present a detailed Monte Carlo simulator of the population of binary systems within the solar neighborhood. We have used the most up-to-date stellar evolutionary models, a complete treatment of the Roche lobe overflow episode, as well as a full implementation of the orbital evolution of the binary system. Preliminary results are presented for the population of white-dwarf main-sequence binaries, resulting from a common envelope episode. We also study the role played by the binding energy parameter, {lambda}, and by the common envelope efficiency, {alpha}{sub CE}. Finally, results are compared with the population of identified white-dwarf main-sequence binaries.

  14. The structure of common-envelope remnants

    NASA Astrophysics Data System (ADS)

    Hall, Philip D.

    2015-05-01

    evolved stars. These formulae can be used to better compute the outcome of common-envelope evolution with rapid evolution codes. We find that the new formulae are necessary for accurate predictions of the properties of post-common envelope systems. Finally, we use detailed remnant models of massive stars to investigate whether hydrogen may be retained after a common-envelope phase to the point of core-collapse and so be observable in supernovae. We find that this is possible and thus common-envelope evolution may contribute to the formation of Type IIb supernovae.

  15. Monte Carlo Population Synthesis of Post-common-envelope White Dwarf Binaries and Type Ia supernova Rate

    NASA Astrophysics Data System (ADS)

    Ablimit, Iminhaji; Maeda, Keiichi; Li, Xiang-Dong

    2016-07-01

    Binary population synthesis (BPS) studies provide a comprehensive way to understand the evolution of binaries and their end products. Close white dwarf (WD) binaries have crucial characteristics for examining the influence of unresolved physical parameters on binary evolution. In this paper, we perform Monte Carlo BPS simulations, investigating the population of WD/main-sequence (WD/MS) binaries and double WD binaries using a publicly available binary star evolution code under 37 different assumptions for key physical processes and binary initial conditions. We considered different combinations of the binding energy parameter (λ g: considering gravitational energy only; λ b: considering both gravitational energy and internal energy; and λ e: considering gravitational energy, internal energy, and entropy of the envelope, with values derived from the MESA code), CE efficiency, critical mass ratio, initial primary mass function, and metallicity. We find that a larger number of post-CE WD/MS binaries in tight orbits are formed when the binding energy parameters are set by λ e than in those cases where other prescriptions are adopted. We also determine the effects of the other input parameters on the orbital periods and mass distributions of post-CE WD/MS binaries. As they contain at least one CO WD, double WD systems that evolved from WD/MS binaries may explode as type Ia supernovae (SNe Ia) via merging. In this work, we also investigate the frequency of two WD mergers and compare it to the SNe Ia rate. The calculated Galactic SNe Ia rate with λ = λ e is comparable to the observed SNe Ia rate, ∼8.2 × 10‑5 yr‑1 – ∼4 × 10‑3 yr‑1 depending on the other BPS parameters, if a DD system does not require a mass ratio higher than ∼0.8 to become an SNe Ia. On the other hand, a violent merger scenario, which requires the combined mass of two CO WDs ≥ 1.6M ⊙ and a mass ratio >0.8, results in a much lower SNe Ia rate than is observed.

  16. Monte Carlo Population Synthesis of Post-common-envelope White Dwarf Binaries and Type Ia supernova Rate

    NASA Astrophysics Data System (ADS)

    Ablimit, Iminhaji; Maeda, Keiichi; Li, Xiang-Dong

    2016-07-01

    Binary population synthesis (BPS) studies provide a comprehensive way to understand the evolution of binaries and their end products. Close white dwarf (WD) binaries have crucial characteristics for examining the influence of unresolved physical parameters on binary evolution. In this paper, we perform Monte Carlo BPS simulations, investigating the population of WD/main-sequence (WD/MS) binaries and double WD binaries using a publicly available binary star evolution code under 37 different assumptions for key physical processes and binary initial conditions. We considered different combinations of the binding energy parameter (λ g: considering gravitational energy only; λ b: considering both gravitational energy and internal energy; and λ e: considering gravitational energy, internal energy, and entropy of the envelope, with values derived from the MESA code), CE efficiency, critical mass ratio, initial primary mass function, and metallicity. We find that a larger number of post-CE WD/MS binaries in tight orbits are formed when the binding energy parameters are set by λ e than in those cases where other prescriptions are adopted. We also determine the effects of the other input parameters on the orbital periods and mass distributions of post-CE WD/MS binaries. As they contain at least one CO WD, double WD systems that evolved from WD/MS binaries may explode as type Ia supernovae (SNe Ia) via merging. In this work, we also investigate the frequency of two WD mergers and compare it to the SNe Ia rate. The calculated Galactic SNe Ia rate with λ = λ e is comparable to the observed SNe Ia rate, ˜8.2 × 10‑5 yr‑1 – ˜4 × 10‑3 yr‑1 depending on the other BPS parameters, if a DD system does not require a mass ratio higher than ˜0.8 to become an SNe Ia. On the other hand, a violent merger scenario, which requires the combined mass of two CO WDs ≥ 1.6M ⊙ and a mass ratio >0.8, results in a much lower SNe Ia rate than is observed.

  17. COMMON ENVELOPE: ENTHALPY CONSIDERATION

    SciTech Connect

    Ivanova, N.; Chaichenets, S.

    2011-04-20

    In this Letter, we discuss a modification to the criterion for the common envelope (CE) event to result in envelope dispersion. We emphasize that the current energy criterion for the CE phase is not sufficient for an instability of the CE, nor for an ejection. However, in some cases, stellar envelopes undergo stationary mass outflows, which are likely to occur during the slow spiral-in stage of the CE event. We propose the condition for such outflows, in a manner similar to the currently standard {alpha}{sub CE}{lambda}-prescription but with an addition of P/{rho} term in the energy balance equation, accounting therefore for the enthalpy of the envelope rather than merely the gas internal energy. This produces a significant correction, which might help to dispense with an unphysically high value of energy efficiency parameter during the CE phase, currently required in the binary population synthesis studies to make the production of low-mass X-ray binaries with a black hole companion to match the observations.

  18. A carbon dwarf wearing a Necklace: first proof of accretion in a post-common-envelope binary central star of a planetary nebula with jets

    NASA Astrophysics Data System (ADS)

    Miszalski, Brent; Boffin, Henri M. J.; Corradi, Romano L. M.

    2013-01-01

    The formation of collimated outflows or jets in planetary nebulae (PNe) is not well understood. There is no evidence for active accretion discs in PNe, making it difficult to decide which of the several proposed jet formation scenarios may be correct. A handful of wide binary central stars of PNe are known to have accreted carbon and slow neutron capture (s-process) enhanced material, the immediate progenitors of barium stars; however, no close binary analogues are known to have passed through a common-envelope (CE) phase. Here we present spectroscopy of the Necklace taken near light-curve minimum that for the first time reveals a carbon-rich (C/O > 1) companion, a carbon dwarf, in a post-CE central star. As unevolved stars do not produce carbon, the chemical enhancement of the secondary can only be explained by accretion from the primary. Accretion most likely happened prior to the CE phase via wind accretion as not enough material can be accreted during the short CE phase. The pair of jets in the Necklace, which are observed to be older than the PN, are therefore likely to have been launched from an accretion disc around the companion during this early accretion phase. This discovery adds significant weight to the emerging scenario that jets in post-CE PNe are primarily launched by an accretion disc around a main-sequence companion before the CE phase.

  19. THE WIRED SURVEY. III. AN INFRARED EXCESS AROUND THE ECLIPSING POST-COMMON ENVELOPE BINARY SDSS J030308.35+005443.7

    SciTech Connect

    Debes, John H.; Hoard, D. W.; Farihi, Jay; Wachter, Stefanie; Leisawitz, David T.; Cohen, Martin

    2012-11-01

    We present the discovery with WISE of a significant infrared excess associated with the eclipsing post-common envelope binary SDSS J030308.35+005443.7, the first excess discovered around a non-interacting white dwarf+main-sequence M dwarf binary. The spectral energy distribution of the white dwarf+M dwarf companion shows significant excess longward of 3 {mu}m. A T {sub eff} of 8940 K for the white dwarf is consistent with a cooling age >2 Gyr, implying that the excess may be due to a recently formed circumbinary dust disk of material that extends from the tidal truncation radius of the binary at 1.96 R {sub Sun} out to <0.8 AU, with a total mass of {approx}10{sup 20} g. We also construct WISE and follow-up ground-based near-infrared light curves of the system and find variability in the K band that appears to be in phase with ellipsoidal variations observed in the visible. The presence of dust might be due to (1) material being generated by the destruction of small rocky bodies that are being perturbed by an unseen planetary system or (2) dust condensing from the companion's wind. The high inclination of this system and the presence of dust make it an attractive target for M dwarf transit surveys and long-term photometric monitoring.

  20. The quest for companions to post-common envelope binaries. IV. The 2:1 mean-motion resonance of the planets orbiting NN Serpentis

    NASA Astrophysics Data System (ADS)

    Beuermann, K.; Dreizler, S.; Hessman, F. V.

    2013-07-01

    We present 69 new mid-eclipse times of the young post-common envelope binary (PCEB) NN Ser, which was previously suggested to possess two circumbinary planets. We have interpreted the observed eclipse-time variations in terms of the light-travel time effect caused by two planets, exhaustively covering the multi-dimensional parameter space by fits in the two binary and ten orbital parameters. We supplemented the fits by stability calculations for all models with an acceptable χ2. An island of secularly stable 2:1 resonant solutions exists, which coincides with the global χ2 minimum. Our best-fit stable solution yields current orbital periods Po = 15.47 yr and Pi = 7.65 yr and eccentricities eo = 0.14 and ei = 0.22 for the outer and inner planets, respectively. The companions qualify as giant planets, with masses of 7.0 MJup and 1.7 MJup for the case of orbits coplanar with that of the binary. The two-planet model that starts from the present system parameters has a lifetime greater than 108 yr, which significantly exceeds the age of NN Ser of 106 yr as a PCEB. The resonance is characterized by libration of the resonant variable Θ1 and circulation of , the difference between the arguments of periapse of the two planets. No stable nonresonant solutions were found, and the possibility of a 5:2 resonance suggested previously by us is now excluded at the 99.3% confidence level. Table 1 is available in electronic form at http://www.aanda.org

  1. Search with UVES and X-Shooter for signatures of the low-mass secondary in the post common-envelope binary AA Doradus

    NASA Astrophysics Data System (ADS)

    Hoyer, D.; Rauch, T.; Werner, K.; Hauschildt, P. H.; Kruk, J. W.

    2015-06-01

    Context. AA Dor is a close, totally eclipsing, post common-envelope binary with an sdOB-type primary star and an extremely low-mass secondary star, located close to the mass limit of stable central hydrogen burning. Within error limits, it may either be a brown dwarf or a late M-type dwarf. Aims: We aim to extract the secondary's contribution to the phase-dependent composite spectra. The spectrum and identified lines of the secondary decide on its nature. Methods: In January 2014, we measured the phase-dependent spectrum of AA Dor with X-Shooter over one complete orbital period. Since the secondary's rotation is presumable synchronized with the orbital period, its surface strictly divides into a day and night side. Therefore, we may obtain the spectrum of its cool side during its transit and of its hot, irradiated side close to its occultation. We developed the Virtual Observatory (VO) tool TLISA to search for weak lines of a faint companion in a binary system. We successfully applied it to the observations of AA Dor. Results: We identified 53 spectral lines of the secondary in the ultraviolet-blue, visual, and near-infrared X-Shooter spectra that are strongest close to its occultation. We identified 57 (20 additional) lines in available Ultraviolet and Visual Echelle Spectrograph (UVES) spectra from 2001. The lines are mostly from C ii-iii and O ii, typical for a low-mass star that is irradiated and heated by the primary. We verified the orbital period of P = 22 597.033201 ± 0.00007 s and determined the orbital velocity K_sec = 232.9+16.6-6.5 km s-1 of the secondary. The mass of the secondary is M_sec = 0.081+0.018-0.010 M_⊙ and, hence, it is not possible to reliably determine a brown dwarf or an M-type dwarf nature. Conclusions: Although we identified many emission lines of the secondary's irradiated surface, the resolution and signal-to-noise ratio of our UVES and X-Shooter spectra are not good enough to extract a good spectrum of the secondary

  2. Common Envelope and the Binding Energy Consideration

    NASA Astrophysics Data System (ADS)

    Irawati, P.; Mahasena, P.

    2014-08-01

    We report the results of our study on the common-envelope phase of the cataclysmic variables. We are investigating the role of additional energies, such as recombination energy and internal energy, in expelling the envelope of the primary star. In this work, we use the TWIN stellar evolution code which can evolve both stars in binary simultaneously. We analysed the energies involved by considering the binding energy of the core at the onset of the common envelope phase. The core of the primary is calculated using the hydrogen-exhausted layer with 10% hydrogen fraction. Our preliminary result shows that the internal energy plays a significant role while the recombination energy has only a small contribution to the energy budget of the cataclysmic variable evolution.

  3. Asymmetric Accretion Flows within a Common Envelope

    NASA Astrophysics Data System (ADS)

    MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2015-04-01

    This paper examines flows in the immediate vicinity of stars and compact objects dynamically inspiralling within a common envelope (CE). Flow in the vicinity of the embedded object is gravitationally focused, leading to drag and potentially to gas accretion. This process has been studied numerically and analytically in the context of Hoyle-Lyttleton accretion (HLA). Yet, within a CE, accretion structures may span a large fraction of the envelope radius, and in so doing sweep across a substantial radial gradient of density. We quantify these gradients using detailed stellar evolution models for a range of CE encounters. We provide estimates of typical scales in CE encounters that involve main sequence stars, white dwarfs, neutron stars, and black holes with giant-branch companions of a wide range of masses. We apply these typical scales to hydrodynamic simulations of three-dimensional HLA with an upstream density gradient. This density gradient breaks the symmetry that defines HLA flow, and imposes an angular momentum barrier to accretion. Material that is focused into the vicinity of the embedded object thus may not be able to accrete. As a result, accretion rates drop dramatically, by one to two orders of magnitude, while drag rates are only mildly affected. We provide fitting formulae to the numerically derived rates of drag and accretion as a function of the density gradient. The reduced ratio of accretion to drag suggests that objects that can efficiently gain mass during CE evolution, such as black holes and neutron stars, may grow less than implied by the HLA formalism.

  4. Common envelope events with low-mass giants: understanding the energy budget

    NASA Astrophysics Data System (ADS)

    Nandez, J. L. A.; Ivanova, N.

    2016-08-01

    Common envelope events are important interactions between two binary stars that lead to the formation of close binary systems. We present here a systematic three-dimensional study in which we model common envelope events with low-mass giant donors. The results allow us to revise the energy formalism that is usually used to determine common envelope event outcomes. We show that the energy budget for this type of system should include the recombination energy, and that it also must take into account that a significant fraction of the released orbital energy is taken away by the ejecta. We provide three ways in which our results can be used by binary population synthesis studies: a relation that links the observed post-common envelope binary with the initial binary parameters, a fitting formula for the $\\alpha_{\\rm ce}\\lambda$ parameter of the standard energy formalism, and a revised energy formalism that takes into account both the recombination energy and the energy that is taken away by the ejecta.

  5. Common envelope events with low-mass giants: understanding the energy budget

    NASA Astrophysics Data System (ADS)

    Nandez, J. L. A.; Ivanova, N.

    2016-08-01

    Common envelope events are important interactions between two binary stars that lead to the formation of close binary systems. We present here a systematic three-dimensional study in which we model common envelope events with low-mass giant donors. The results allow us to revise the energy formalism that is usually used to determine common envelope event outcomes. We show that the energy budget for this type of system should include the recombination energy, and that it also must take into account that a significant fraction of the released orbital energy is taken away by the ejecta. We provide three ways in which our results can be used by binary population synthesis studies: a relation that links the observed post-common envelope binary with the initial binary parameters, a fitting formula for the αceλ parameter of the standard energy formalism, and a revised energy formalism that takes into account both the recombination energy and the energy that is taken away by the ejecta.

  6. Common envelope events with low-mass giants: understanding the energy budget

    NASA Astrophysics Data System (ADS)

    Nandez, J. L. A.; Ivanova, N.

    2016-05-01

    Common envelope events are important interactions between two binary stars that lead to the formation of close binary systems. We present here a systematic three-dimensional study in which we model common envelope events with low-mass giant donors. The results allow us to revise the energy formalism that is usually used to determine common envelope event outcomes. We show that the energy budget for this type of system should include the recombination energy, and that it also must take into account that a significant fraction of the released orbital energy is taken away by the ejecta. We provide three ways in which our results can be used by binary population synthesis studies: a relation that links the observed post-common envelope binary with the initial binary parameters, a fitting formula for the αceλ parameter of the standard energy formalism, and a revised energy formalism that takes into account both the recombination energy and the energy that is taken away by the ejecta.

  7. Empirical Constraints on Common Envelope Evolution in Wide Binaries

    NASA Astrophysics Data System (ADS)

    Geller, Aaron M.; Hurley, J. R.; Mathieu, R. D.

    2012-01-01

    If a giant star in a binary overfills its Roche lobe, the giant's convective envelope may respond by expanding faster than its Roche lobe, transferring mass on a dynamical time scale, and creating a common envelope (CE) that engulfs both stars. Orbital energy may then be transferred from the binary to the envelope, which can shrink the orbit and drive away the material, leaving behind a detached system containing the white dwarf core of the giant. Such a CE event is thought to be critical for explaining certain populations of exotic stars (e.g., cataclysmic variables). Yet the application of CE evolution to binary population synthesis and N-body or Monte Carlo star cluster models requires many poorly constrained assumptions, which may lead to unphysical evolutionary paths. In fact, we find that such fictitious systems are created regularly within our N-body models of the old (7 Gyr) open cluster NGC 188. Most notably, the model predicts a population of post-CE long-period ( 1000 days) circular solar-type main sequence - white dwarf binaries, that are not present in our observations of the true binaries in NGC 188, or any other solar-type binary population in the literature (in star clusters or in the field). The absence of such post-CE systems in real binary populations places important limits on parameters used in most models of CE evolution, and may suggest that more binaries undergo stable mass transfer than has previously been assumed. We discuss how various solutions to this problem would impact other observable stellar populations, including cataclysmic variables, symbiotic stars and blue stragglers.

  8. ON THE BINDING ENERGY PARAMETER {lambda} OF COMMON ENVELOPE EVOLUTION

    SciTech Connect

    Xu Xiaojie; Li Xiangdong

    2010-06-10

    The binding energy parameter {lambda} plays an important role in common envelope evolution. Previous works have already pointed out that {lambda} varies throughout the stellar evolution, though it has been adopted as a constant in most of the population synthesis calculations. We have systematically calculated the binding energy parameter {lambda} for both Population I and Population II stars of masses 1-20 M {sub sun}, taking into account the contribution from the internal energy of stellar matter. We present fitting formulae for {lambda} that can be incorporated into future population synthesis investigations. We also briefly discuss the possible applications of the results in binary evolutions.

  9. On the Binding Energy Parameter λ of Common Envelope Evolution

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-Jie; Li, Xiang-Dong

    2010-06-01

    The binding energy parameter λ plays an important role in common envelope evolution. Previous works have already pointed out that λ varies throughout the stellar evolution, though it has been adopted as a constant in most of the population synthesis calculations. We have systematically calculated the binding energy parameter λ for both Population I and Population II stars of masses 1-20 M sun, taking into account the contribution from the internal energy of stellar matter. We present fitting formulae for λ that can be incorporated into future population synthesis investigations. We also briefly discuss the possible applications of the results in binary evolutions.

  10. COMMON ENVELOPE EVOLUTION LEADING TO SUPERNOVAE WITH DENSE INTERACTION

    SciTech Connect

    Chevalier, Roger A.

    2012-06-10

    A variety of supernova events, including Type IIn supernovae and ultraluminous supernovae, appear to have lost up to solar masses of their envelopes in tens to hundreds of years leading up to the explosion. In order to explain the close timing of the mass loss and supernova events, we explore the possibility that the mass loss is driven by common envelope evolution of a compact object (neutron star or black hole) in the envelope of a massive star and the supernova is triggered by the inspiral of the compact object to the central core of the companion star. The expected rate of such events is smaller than the observed rate of Type IIn supernovae but the rates may agree within the uncertainties. The mass loss velocity is related to the escape velocity from the common envelope system and is comparable to the observed velocity of hundreds of kilometers per second in Type IIn events. The mass loss is expected to be denser near the equatorial plane of the binary system and there is good evidence that the circumstellar media in Type IIn supernovae are asymmetric. Some of these supernova types show evidence for energies in excess of the canonical 10{sup 51} erg, which might be the result of explosions from rapid accretion onto a compact object through a disk.

  11. The binding energy parameter for common envelope evolution

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Jia, Kun; Li, Xiang-Dong

    2016-08-01

    The binding energy parameter λ plays a vital role in common envelope evolution. Though it is well known that λ takes different values for stars with different masses and varies during stellar evolution, it has been erroneously adopted as a constant in most population synthesis calculations. We have systematically calculated the values of λ for stars of masses 1 – 60 M ⊙ by use of an updated stellar evolution code, taking into account the contribution from both gravitational energy and internal energy to the binding energy of the envelope. We adopt the criterion for the core-envelope boundary advocated by Ivanova. A new kind of λ with an enthalpy prescription is also investigated. We present fitting formulae for the calculated values of various kinds of λ, which can be used in future population synthesis studies.

  12. DUST FORMATION IN THE EJECTA OF COMMON ENVELOPE SYSTEMS

    SciTech Connect

    Lue Guoliang; Zhu Chunhua; Podsiadlowski, Philipp

    2013-05-10

    The material that is ejected in a common-envelope (CE) phase in a close binary system provides an ideal environment for dust formation. By constructing a simple toy model to describe the evolution of the density and the temperature of CE ejecta and using the AGBDUST code to model dust formation, we show that dust can form efficiently in this environment. The actual dust masses produced in the CE ejecta depend strongly on their temperature and density evolution. We estimate the total dust masses produced by CE evolution by means of a population synthesis code and show that, compared to dust production in asymptotic giant branch stars, the dust produced in CE ejecta may be quite significant and could even dominate under certain circumstances.

  13. Considerations on the role of fall-back discs in the final stages of the common envelope binary interaction

    NASA Astrophysics Data System (ADS)

    Kuruwita, Rajika L.; Staff, Jan; De Marco, Orsola

    2016-09-01

    The common envelope interaction is thought to be the gateway to all evolved compact binaries and mergers. Hydrodynamic simulations of the common envelope interaction between giant stars and their companions are restricted to the dynamical, fast, in-spiral phase. They find that the giant envelope is lifted during this phase, but remains mostly bound to the system. At the same time, the orbital separation is greatly reduced, but in most simulations it levels off at values larger than measured from observations. We conjectured that during the post-in-spiral phase the bound envelope gas will return to the system. Using hydrodynamic simulations, we generate initial conditions for our simulation that result in a fall-back disc with total mass and angular momentum in line with quantities from the simulations of Passy et al. We find that the simulated fall-back event reduces the orbital separation efficiently, but fails to unbind the gas before the separation levels off once again. We also find that more massive fall-back discs reduce the orbital separation more efficiently, but the efficiency of unbinding remains invariably very low. From these results we deduce that unless a further energy source contributes to unbinding the envelope (such as was recently tested by Nandez et al.), all common envelope interactions would result in mergers. On the other hand, additional energy sources are unlikely to help, on their own, to reduce the orbital separation. We conclude by discussing our dynamical fall-back event in the context of a thermally regulated post-common envelope phase.

  14. Constraints on common envelope magnetic fields from observations of jets in planetary nebulae

    NASA Astrophysics Data System (ADS)

    Tocknell, James; De Marco, Orsola; Wardle, Mark

    2014-04-01

    The common envelope (CE) interaction describes the swallowing of a nearby companion by a growing, evolving star. CEs that take place during the asymptotic giant branch phase of the primary may lead to the formation of a planetary nebula (PN) with a post-CE close binary in the middle. We have used published observations of masses and kinematics of jets in four post-CE PN to infer physical characteristics of the CE interaction. In three of the four systems studied, Abell 63, ETHOS 1 and the Necklace PN, the kinematics indicate that the jets were launched a few thousand years before the CE and we favour a scenario where this happened before Roche lobe overflow, although better models of wind accretion and wind Roche lobe overflow are needed. The magnetic fields inferred to launch pre-CE jets are of the order of a few gauss. In the fourth case, NGC 6778, the kinematics indicate that the jets were launched about 3000 yr after the CE interaction. Magnetic fields of the order of a few hundreds to a few thousands gauss are inferred in this case, approximately in line with predictions of post-CE magnetic fields. However, we remark that in the case of this system, we have not been able to find a reasonable scenario for the formation of the two jet pairs observed: the small orbital separation may preclude the formation of even one accretion disc able to supply the necessary accretion rate to cause the observed jets.

  15. ON THE ACCRETION-FED GROWTH OF NEUTRON STARS DURING COMMON ENVELOPE

    SciTech Connect

    MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2015-01-01

    This paper models the orbital inspiral of a neutron star (NS) through the envelope of its giant-branch companion during a common envelope (CE) episode. These CE episodes are necessary to produce close pairs of NSs that can inspiral and merge due to gravitational wave losses in less than a Hubble time. Because cooling by neutrinos can be very efficient, NSs have been predicted to accumulate significant mass during CE events, perhaps enough to lead them to collapse to black holes. We revisit this conclusion with the additional consideration of CE structure, particularly density gradients across the embedded NS's accretion radius. This work is informed by our recent numerical simulations that find that the presence of a density gradient strongly limits accretion by imposing a net angular momentum to the flow around the NS. Our calculations suggest that NSs should survive CE encounters. They accrete only modest amounts of envelope material, ≲ 0.1 M {sub ☉}, which is broadly consistent with mass determinations of double NS binaries. With less mass gain, NSs must spiral deeper to eject their CE, leading to a potential increase in mergers. The survival of NSs in CE events has implications for the formation mechanism of observed double NS binaries, as well as for predicted rates of NS binary gravitational wave inspirals and their electromagnetic counterparts.

  16. Formation of high-field magnetic white dwarfs from common envelopes

    PubMed Central

    Nordhaus, Jason; Wellons, Sarah; Spiegel, David S.; Metzger, Brian D.; Blackman, Eric G.

    2011-01-01

    The origin of highly magnetized white dwarfs has remained a mystery since their initial discovery. Recent observations indicate that the formation of high-field magnetic white dwarfs is intimately related to strong binary interactions during post-main-sequence phases of stellar evolution. If a low-mass companion, such as a planet, brown dwarf, or low-mass star, is engulfed by a post-main-sequence giant, gravitational torques in the envelope of the giant lead to a reduction of the companion’s orbit. Sufficiently low-mass companions in-spiral until they are shredded by the strong gravitational tides near the white dwarf core. Subsequent formation of a super-Eddington accretion disk from the disrupted companion inside a common envelope can dramatically amplify magnetic fields via a dynamo. Here, we show that these disk-generated fields are sufficiently strong to explain the observed range of magnetic field strengths for isolated, high-field magnetic white dwarfs. A higher-mass binary analogue may also contribute to the origin of magnetar fields. PMID:21300910

  17. Formation of high-field magnetic white dwarfs from common envelopes.

    PubMed

    Nordhaus, Jason; Wellons, Sarah; Spiegel, David S; Metzger, Brian D; Blackman, Eric G

    2011-02-22

    The origin of highly magnetized white dwarfs has remained a mystery since their initial discovery. Recent observations indicate that the formation of high-field magnetic white dwarfs is intimately related to strong binary interactions during post-main-sequence phases of stellar evolution. If a low-mass companion, such as a planet, brown dwarf, or low-mass star, is engulfed by a post-main-sequence giant, gravitational torques in the envelope of the giant lead to a reduction of the companion's orbit. Sufficiently low-mass companions in-spiral until they are shredded by the strong gravitational tides near the white dwarf core. Subsequent formation of a super-Eddington accretion disk from the disrupted companion inside a common envelope can dramatically amplify magnetic fields via a dynamo. Here, we show that these disk-generated fields are sufficiently strong to explain the observed range of magnetic field strengths for isolated, high-field magnetic white dwarfs. A higher-mass binary analogue may also contribute to the origin of magnetar fields. PMID:21300910

  18. Constraints on Common Envelope Magnetic Fields from Observations of Jets in Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    De Marco, Orsola; Tocknell, J.; Wardle, M.

    2014-01-01

    The common envelope (CE) interaction describes the swallowing of a nearby companion by a growing, evolving star. CEs that take place during the asymptotic giant branch phase of the primary and may lead to the formation of a planetary nebula (PN) with a post-CE close binary in the middle. We have used published observations of masses and kinematics of jets in four post-CE PN to infer physical characteristics of the CE interaction. In three of the four systems studied, Abell 63, ETHOS 1 and the Necklace PN, the kinematics indicate that the jets were launched a few thousand years before the CE and we favour a scenario where this happened before Roche lobe overflow, although better models of wind accretion and wind Roche lobe overflow are needed. The magnetic fields inferred to launch pre-CE jets are of the order of a few Gauss. In the fourth case, NGC 6778, the kinematics indicate that the jets were launched about 3000 years after the CE interaction. Magnetic fields of the order of a few hundreds to a few thousands Gauss are inferred in this case, approximately in line with predictions of post-CE magnetic fields. However, we remark that in the case of this system, we cannot find a reasonable scenario for the formation of the two jet pairs observed: the small orbital separation would preclude the formation of even one accretion disk able to supply the necessary accretion rate to cause the observed jets. Additional and improved observations of post-CE PN will provide a powerful tool to constrain the CE interaction.

  19. Use HMXB offsets to constrain the natal kicks and common envelope efficinecy

    NASA Astrophysics Data System (ADS)

    Zuo, Zhaoyu

    2015-08-01

    Using an up-to-date evolutionary population synthesis code, we have calculated the spatial offsets of high mass X-ray binaries and their correlation to the luminosities. Parameters affecting the orbit and system velocity of a binary are examined systematically. From the calculated results we find that the common envelope efficiency is possibly around ~0.8-1.0 and make several constraints on the natal kicks.

  20. Accretion and activity on the post-common-envelope binary RR Caeli

    NASA Astrophysics Data System (ADS)

    Ribeiro, T.; Baptista, R.; Kafka, S.; Dufour, P.; Gianninas, A.; Fontaine, G.

    2013-08-01

    Context. Current scenarios for the evolution of interacting close binaries - such as cataclysmic variables (CVs) - rely mainly on our understanding of low-mass star angular momentum loss (AML) mechanisms. The coupling of stellar wind with its magnetic field, i.e., magnetic braking, is the most promising mechanism believed to drive AML in these stars. There are basically two properties thought to drive magnetic braking: the stellar magnetic field and the stellar wind. Understanding the mechanisms that drive AML therefore requires a comprehensive understanding of these two properties as well. Aims. RR Cae is a well-known nearby (d = 20 pc) eclipsing DA+M binary with an orbital period of P = 7.29 h. The system harbors a metal-rich cool DA white dwarf (WD) and a highly active M-dwarf locked in synchronous rotation. The metallicity of the WD suggests that wind accretion is taking place, which provides a good opportunity to obtain the mass-loss rate of the M-dwarf component. We aim to reach a better understanding of the AML mechanisms in close binaries by characterizing the relevant properties of the M-dwarf component of this system. Methods. We analyzed multi-epoch time-resolved high-resolution spectra of RR Cae in search for traces of magnetic activity and accretion. We selected a number of well-known chromospheric activity indicators and studied their phase-dependence and long-term behavior. Indirect-imaging tomographic techniques were also applied to provide the surface brightness distribution of the magnetically active M-dwarf. The blue part of the spectrum was modeled using a state-of-the-art atmosphere model to constrain the WD properties and its metal enrichment. The latter was used to improve the determination of the mass-accretion rate from the M-dwarf wind. Results. Doppler imaging of the M-dwarf component of RR Cae reveals a polar feature similar to those observed in fast-rotating solar-type stars. Analysis of tomographic reconstruction of the Hα emission line reveals two components, one traces the motion of the M dwarf and is generated by chromospheric activity, while the other clearly follows the motion of the WD. The presence of metals in the WD spectrum suggests that this component arises from accretion of the M-dwarf wind. A model fit to the WD spectrum provides Teff = (7260 ± 250) K and log g = (7.8 ± 0.1) dex with a metallicity of (log [X/X⊙]) = (-2.8Â ± 0.1) dex. This maps into a mass-accretion rate of M⊙acc = (7 ± 2) × 10-16M⊙ yr-1 onto the surface of the WD. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under program ID 076.D-0142.

  1. The quest for companions to post-common envelope binaries. III. A reexamination of HW Virginis

    NASA Astrophysics Data System (ADS)

    Beuermann, K.; Dreizler, S.; Hessman, F. V.; Deller, J.

    2012-07-01

    We report new mid-eclipse times of the short-period sdB/dM binary HW Virginis, which differ substantially from the times predicted by a previous model. The proposed orbits of the two planets in that model are found to be unstable. We present a new secularly stable solution, which involves two companions orbiting HW Vir with periods of 12.7 yr and 55 ± 15 yr. For orbits coplanar with the binary, the inner companion is a giant planet with mass M3 sin i3 ≃ 14 MJup and the outer one a brown dwarf or low-mass star with a mass of M4 sin i4 = 30-120 MJup. Using the mercury6 code, we find that such a system would be stable over more than 107 yr, in spite of the sizeable interaction. Our model fits the observed eclipse-time variations by the light-travel time effect alone, without invoking any additional process, and provides support for the planetary hypothesis of the eclipse-time variations in close binaries. The signature of non-Keplerian orbits may be visible in the data.

  2. Photometry of the post-common-envelope binary PG 0308+096

    NASA Astrophysics Data System (ADS)

    Somers, M. W.; Lockley, J. J.; Naylor, T.; Wood, Janet H.

    1996-06-01

    We present R- and H-band photometry of PG 0308+096. We demonstrate that the orbital modulation is consistent with that of a dwarf M star heated by a DA white dwarf within the constraints given by the kinematic parameters. By fitting the photometry with an irradiation model we determine that the radius of the white dwarf is 0.019<=R_wd<=0.026 R_ (90 per cent confidence). In order to derive these limits, we have developed a fitting procedure that takes account of the external constraints derived from the spectroscopic analysis by Saffer et al. We determine that the period of the system is 0.286654+/-0.00000078d, which is one of the cycle count aliases considered by Saffer et al. We show that the Hα emission from the surface of the red star can be modelled as either optically thick or thin, but in the latter case the red dwarf must have intrinsic emission.

  3. Masses and Envelope Binding Energies of Primary Stars at the Onset of a Common Envelope

    NASA Astrophysics Data System (ADS)

    van der Sluys, Marc; Politano, Michael; Taam, Ronald E.

    2010-12-01

    We present basic properties of primary stars that initiate a common envelope (CE) in a binary, while on the giant branch. We use the population-synthesis code described in Politano et al. [1] and follow the evolution of a population of binary stars up to the point where the primary fills its Roche lobe and initiates a CE. We then collect the properties of each system, in particular the donor mass and the binding energy of the donor's envelope, which are important for the treatment of a CE. We find that for most CEs, the donor mass is sufficiently low to define the core-envelope boundary reasonably well. We compute the envelope-structure parameter λenv from the binding energy and compare its distribution to typical assumptions that are made in population-synthesis codes. We conclude that λenv varies appreciably and that the assumption of a constant value for this parameter results in typical errors of 20-50%. In addition, such an assumption may well result in the implicit assumption of unintended and/or unphysical values for the CE parameter αCE. Finally, we discuss accurate existing analytic fits for the envelope binding energy, which make these oversimplified assumptions for λenv, and the use of λenv in general, unnecessary.

  4. Hydrodynamic Moving-mesh Simulations of the Common Envelope Phase in Binary Stellar Systems

    NASA Astrophysics Data System (ADS)

    Ohlmann, Sebastian T.; Röpke, Friedrich K.; Pakmor, Rüdiger; Springel, Volker

    2016-01-01

    The common envelope (CE) phase is an important stage in binary stellar evolution. It is needed to explain many close binary stellar systems, such as cataclysmic variables, SN Ia progenitors, or X-ray binaries. To form the resulting close binary, the initial orbit has to shrink, thereby transferring energy to the primary giant's envelope that is hence ejected. The details of this interaction, however, are still not understood. Here, we present new hydrodynamic simulations of the dynamical spiral-in forming a CE system. We apply the moving-mesh code arepo to follow the interaction of a 1{M}⊙ compact star with a 2{M}⊙ red giant possessing a 0.4{M}⊙ core. The nearly Lagrangian scheme combines advantages of smoothed particle hydrodynamics and traditional grid-based hydrodynamic codes and allows us to capture also small flow features at high spatial resolution. Our simulations reproduce the initial transfer of energy and angular momentum from the binary core to the envelope by spiral shocks seen in previous studies, but after about 20 orbits a new phenomenon is observed. Large-scale flow instabilities are triggered by shear flows between adjacent shock layers. These indicate the onset of turbulent convection in the CE, thus altering the transport of energy on longer timescales. At the end of our simulation, only 8% of the envelope mass is ejected. The failure to unbind the envelope completely may be caused by processes on thermal timescales or unresolved microphysics.

  5. Comparisons Between SPH and Grid-Based Simulations of the Common Envelope Phase

    NASA Astrophysics Data System (ADS)

    Passy, Jean-Claude; Fryer, C. L.; Diehl, S.; De Marco, O.; Mac Low, M.; Herwig, F.; Oishi, J. S.

    2011-01-01

    The common envelope (CE) interaction between a giant star and a lower-mass companion provides a formation channel leading eventually to Type Ia supernovae, sdB stars and bipolar PNe. More broadly, it is an essential ingredient for any population synthesis study including binaries, e.g. cataclysmic variables. Occurring on a short time scale - typically between one and ten years, the CE interaction itself has so far never been observed with certainty but the existence of companions in close orbits around evolved stars, whose precursor's radius was larger than today's orbital separation, vouches for such interaction taking place frequently. Via a detailed study of the energetics and the use of stellar evolution models, we derived in our previous paper the efficiency α of the CE interaction from a carefully selected and statistically analyzed sample of systems thought to be outcomes of a CE interaction. We deduced the initial configuration of those systems using stellar models, and derived a possible inverse dependence of α with the companion to primary mass ratio. Here, we compare these predictions to numerical simulations with two different codes. Enzo is a 3D adaptive mesh refinement grid-based code. For our stellar problem we have modified the way gravity and boundary conditions are treated in this code. The SNSPH code is a 3D hydrodynamics SPH code using tree gravity. The results from both codes for different companion masses and different types of primary stars are consistent with each other. Those results include a resolution study of a 0.88 M⊙ red giant interacting with a 0.9, 0.6 and 0.3 M⊙ white dwarf, respectively. Those systems reach a final separation of 25, 18 and 10 R⊙, respectively. In this contribution, we present and discuss those results and compare them to our predictions. This research was funded by NSF grant 0607111.

  6. AN AMR STUDY OF THE COMMON-ENVELOPE PHASE OF BINARY EVOLUTION

    SciTech Connect

    Ricker, Paul M.; Taam, Ronald E. E-mail: r-taam@northwestern.edu

    2012-02-10

    The hydrodynamic evolution of the common-envelope (CE) phase of a low-mass binary composed of a 1.05 M{sub Sun} red giant and a 0.6 M{sub Sun} companion has been followed for five orbits of the system using a high-resolution method in three spatial dimensions. During the rapid inspiral phase, the interaction of the companion with the red giant's extended atmosphere causes about 25% of the CE to be ejected from the system, with mass continuing to be lost at the end of the simulation at a rate {approx}2 M{sub Sun} yr{sup -1}. In the process the resulting loss of angular momentum and energy reduces the orbital separation by a factor of seven. After this inspiral phase the eccentricity of the orbit rapidly decreases with time. The gravitational drag dominates hydrodynamic drag at all times in the evolution, and the commonly used Bondi-Hoyle-Lyttleton prescription for estimating the accretion rate onto the companion significantly overestimates the true rate. On scales comparable to the orbital separation, the gas flow in the orbital plane in the vicinity of the two cores is subsonic with the gas nearly corotating with the red giant core and circulating about the red giant companion. On larger scales, 90% of the outflow is contained within 30 Degree-Sign of the orbital plane, and the spiral shocks in this material leave an imprint on the density and velocity structure. Of the energy released by the inspiral of the cores, only about 25% goes toward ejection of the envelope.

  7. Merging in the common envelope and the origin of early R-type stars

    NASA Astrophysics Data System (ADS)

    Piersanti, L.; Cabezón, R. M.; Zamora, O.; Domínguez, I.; García-Senz, D.; Abia, C.; Straniero, O.

    2010-11-01

    Context. Binary systems experiencing one or two common envelope episodes during the red giant branch or the Hertzsprung gap phases can produce a single star, evolving along the Hayashi track, as a final outcome. Even if these objects are expected to be very common in nature, a proper description of their evolution and physical properties is still missing. Moreover, this scenario (red giant merging scenario) has been invoked as the progenitor systems of early-R stars, by assuming that the physical conditions developed as a consequence of the cores merging could produce the mixing into the convective envelope of fresh carbon that was synthesized during the He-flash. Aims: We analyze in detail the red giant merging scenario to verify if the resulting star develops the physical conditions suitable for a dredge-up of C-enriched material from the core to the envelope. Methods: We performed 3D simulations of the merging stars, to check whether He is burnt efficiently during the formation of a self-sustained disk. We therefore did 1D computations of the accretion phase occurring after the merging and of the following evolution up to the settling of quiescent He-burning in the center. We adopted different assumptions on the amount of angular momentum transferred from the disk to the core and on the angular momentum transport. Results: Efficient He-burning does not occur during the merging, because a very high temperature (T > 108 K) at the disk/He-core interface develops only for a few minutes. Our computations show that the accretion process is the leading parameter in determining the final properties of the merged object. In particular, the thermal energy delivered by the accreted matter determines the heating of the whole newborn core, thus preventing the developing of highly degenerate physical conditions. This occurrence determines the onset of the He-burning with an He-flash milder and closer to the center, as compared to standard RGB stars. Rotation and different

  8. Common envelope mechanisms: constraints from the X-ray luminosity function of high-mass X-ray binaries

    SciTech Connect

    Zuo, Zhao-Yu; Li, Xiang-Dong E-mail: lixd@nju.edu.cn

    2014-12-10

    We use the measured X-ray luminosity function (XLF) of high-mass X-ray binaries (HMXBs) in nearby star-forming galaxies to constrain the common envelope (CE) mechanisms, which play a key role in governing the binary evolution. We find that the XLF can be reproduced quite closely under both CE mechanisms usually adopted, i.e., the α{sub CE} formalism and the γ algorithm, with a reasonable range of parameters considered. Provided that the parameter combination is the same, the γ algorithm is likely to produce more HMXBs than the α{sub CE} formalism, by a factor of up to ∼10. In the framework of the α{sub CE} formalism, a high value of α{sub CE} is required to fit the observed XLF, though it does not significantly affect the global number of the HMXB populations. We present the detailed components of the HMXB populations under the γ algorithm and compare them with those in Zuo et al. and observations. We suggest the distinct observational properties, as well as period distributions of HMXBs, may provide further clues to discriminate between these two types of CE mechanisms.

  9. SIMULATING THE COMMON ENVELOPE PHASE OF A RED GIANT USING SMOOTHED-PARTICLE HYDRODYNAMICS AND UNIFORM-GRID CODES

    SciTech Connect

    Passy, Jean-Claude; Mac Low, Mordecai-Mark; De Marco, Orsola; Fryer, Chris L.; Diehl, Steven; Rockefeller, Gabriel; Herwig, Falk; Oishi, Jeffrey S.; Bryan, Greg L.

    2012-01-01

    We use three-dimensional hydrodynamical simulations to study the rapid infall phase of the common envelope (CE) interaction of a red giant branch star of mass equal to 0.88 M{sub Sun} and a companion star of mass ranging from 0.9 down to 0.1 M{sub Sun }. We first compare the results obtained using two different numerical techniques with different resolutions, and find very good agreement overall. We then compare the outcomes of those simulations with observed systems thought to have gone through a CE. The simulations fail to reproduce those systems in the sense that most of the envelope of the donor remains bound at the end of the simulations and the final orbital separations between the donor's remnant and the companion, ranging from 26.8 down to 5.9 R{sub Sun }, are larger than the ones observed. We suggest that this discrepancy vouches for recombination playing an essential role in the ejection of the envelope and/or significant shrinkage of the orbit happening in the subsequent phase.

  10. Binaries discovered by the SPY survey. VI. Discovery of a low mass companion to the hot subluminous planetary nebula central star EGB 5 - a recently ejected common envelope?

    NASA Astrophysics Data System (ADS)

    Geier, S.; Napiwotzki, R.; Heber, U.; Nelemans, G.

    2011-04-01

    Hot subdwarf B stars (sdBs) in close binary systems are assumed to be formed via common envelope ejection. According to theoretical models, the amount of energy and angular momentum deposited in the common envelope scales with the mass of the companion. That low mass companions near or below the core hydrogen-burning limit are able to trigger the ejection of this envelope is well known. The currently known systems have very short periods ≃0.1-0.3 d. Here we report the discovery of a low mass companion (M2 > 0.14 M⊙) orbiting the sdB star and central star of a planetary nebula EGB 5 with an orbital period of 16.5 d at a minimum separation of 23 R⊙. Its long period is only just consistent with the energy balance prescription of the common envelope. The marked difference between the short and long period systems will provide strong constraints on the common envelope phase, in particular if the masses of the sdB stars can be measured accurately. Due to selection effects, the fraction of sdBs with low mass companions and similar or longer periods may be quite high. Low mass stellar and substellar companions may therefore play a significant role for the still unclear formation of hot subdwarf stars. Furthermore, the nebula around EGB 5 may be the remnant of the ejected common envelope making this binary a unique system to study this short und poorly understood phase of binary evolution. Based on observations at the Paranal Observatory of the European Southern Observatory for programmes No. 167.H-0407(A) and 71.D-0383(A). Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC). Some of the data used in this work were obtained at the William Herschel Telescope (WHT) operated by the Isaac Newton Group of Telescopes (ING).

  11. Post-collision-interaction distortion of low-energy photoelectron spectra associated with double Auger decay

    SciTech Connect

    Gerchikov, L.; Sheinerman, S.

    2011-08-15

    Atomic inner-shell photoionization followed by double Auger decay is investigated. The focus of our study is the effect of post-collision interaction (PCI) on the photoelectron energy distribution. A semi-classical approach is employed to describe the PCI distortion of the photoelectron line shapes associated with both direct and cascade double Auger decays. This approach is shown to be valid at low photoelectron energies, whereas for large incident photon energies it reduces to the eikonal approximation. The theory is applied to the case of Ar 2p photoionization spectra and good agreement with available experimental data is achieved.

  12. On the inclusion of post-MP2 contributions to double-hybrid density functionals.

    PubMed

    Chan, Bun; Goerigk, Lars; Radom, Leo

    2016-01-15

    In this study, we explore the effect of supplementing the DuT spin-component-scaled double-hybrid density functional method with post-second-order Møller-Plesset-type theory (MP2) correlation terms. We find that the inclusion of additional MP3 correlation energies has almost no effect on the performance. Further addition of correlation effects from MP4 generally leads to a small improvement in the performance. However, we find that the inclusion of the higher-order perturbative correlation effects does not rectify some major shortcomings of DuT for more challenging systems, and the use of MP4, in fact, leads to a significant deterioration in the performance in some cases. We also find that the use of correlation energies from CCSD(T) instead of those from MP3 and MP4 does not lead to a substantial improvement over the MP4-based method, both in general and in some difficult cases that we have examined. An additional observation is that, for large systems that are dominated by noncovalent interactions, DuT and the two MPn-based post-MP2 double-hybrid density functional theory (DFT) procedures all benefit from the inclusion of dispersion corrections. Overall, our investigation suggests that the current generation of MP2-based double-hybrid DFT methods may already be providing close to the optimal performance that can be achieved with the double-hybrid methodology paired with spin-component-scaling. Development of even better double hybrids is an active research field, and we hope that our study provides valuable insights. We recommend the continuing use of existing MP2-based double-hybrid methods as a bridging level between hybrid density functional procedures and high-level wave-function-based procedures. PMID:26135403

  13. Double-concave deformity of the polyethylene tibial post in posterior stabilized total knee arthroplasty.

    PubMed

    Niki, Yasuo; Matsumoto, Hideo; Yoshimine, Fumihiro; Toyama, Yoshiaki; Suda, Yasunori; Banks, Scott A

    2010-04-01

    This report describes a unique case of bilateral total knee arthroplasty necessitating revision of the polyethylene insert, which showed prominent marks on the tibial post resulting from repeated seiza-style sitting. The patient presented 7 years postoperatively with knee pain and flexion disturbance due to continuous joint effusion persisting for more than 4 months. Proliferating synovia throughout the joint revealed reactive synovitis to polyethylene particles. The retrieved polyethylene inserts displayed double-concave deformity of the tibial post with burnishing and creep in tibiofemoral articulation. The damage pattern of retrieved polyethylene inserts reflected the data from tibiofemoral contact location obtained using a shape-matching technique in the early postoperative phase. This case provides an example of damage to the polyethylene tibial post caused by a floor-sitting lifestyle and the potential clinical sequelae. PMID:19261434

  14. Recombination energy in double white dwarf formation

    NASA Astrophysics Data System (ADS)

    Nandez, J. L. A.; Ivanova, N.; Lombardi, J. C.

    2015-06-01

    In this Letter, we investigate the role of recombination energy during a common envelope event. We confirm that taking this energy into account helps to avoid the formation of the circumbinary envelope commonly found in previous studies. For the first time, we can model a complete common envelope event, with a clean compact double white dwarf binary system formed at the end. The resulting binary orbit is almost perfectly circular. In addition to considering recombination energy, we also show that between 1/4 and 1/2 of the released orbital energy is taken away by the ejected material. We apply this new method to the case of the double white dwarf system WD 1101+364, and we find that the progenitor system at the start of the common envelope event consisted of an ˜1.5 M⊙ red giant star in an ˜30 d orbit with a white dwarf companion.

  15. A large, long-lived structure near the trojan L5 point in the post common-envelope binary SDSS J1021+1744

    NASA Astrophysics Data System (ADS)

    Irawati, P.; Richichi, A.; Bours, M. C. P.; Marsh, T. R.; Sanguansak, N.; Chanthorn, K.; Hermes, J. J.; Hardy, L. K.; Parsons, S. G.; Dhillon, V. S.; Littlefair, S. P.

    2016-03-01

    SDSS J1021+1744 is a detached, eclipsing white dwarf/M dwarf binary discovered in the Sloan Digital Sky Survey (SDSS). Outside the primary eclipse, the light curves of such systems are usually smooth and characterized by low-level variations caused by tidal distortion and heating of the M star component. Early data on SDSS J1021+1744 obtained in 2012 June were unusual in showing a dip in flux of uncertain origin shortly after the white dwarf's eclipse. Here we present high-time resolution, multiwavelength observations of 35 more eclipses over 1.3 yr, showing that the dip has a lifetime extending over many orbits. Moreover the `dip' is in fact a series of dips that vary in depth, number and position, although they are always placed in the phase interval 1.06-1.26 after the white dwarf's eclipse, near the L5 point in this system. Since SDSS J1021+1744 is a detached binary, it follows that the dips are caused by the transit of the white dwarf by material around the Lagrangian L5 point. A possible interpretation is that they are the signatures of prominences, a phenomenon already known from H α observations of rapidly rotating single stars as well as binaries. What makes SDSS J1021+1744 peculiar is that the material is dense enough to block continuum light. The dips appear to have finally faded out around 2015 May after the first detection by Parsons et al. in 2012, suggesting a lifetime of years.

  16. Post heat treatment effects on double layer metal structures for VLSI applications

    NASA Technical Reports Server (NTRS)

    Wade, T. E.; Trotter, J. D.

    1978-01-01

    The realization of high yield double layer metal systems using wet chemistry processes and the ability to extend yields beyond that attainable with wet chemistry by means of post sintering processes at temperatures below 500 C for potential applications in very large scale integration structures were studied. Yields in excess of 98% and average total contact resistance of less than 150 ohms and 200 ohms were realized for a series of 560 vias of 0.5 X 0.5 mils and 0.2 X 0.2 mils in size, respectively.

  17. Randomised double-blind comparative study of dexmedetomidine and tramadol for post-spinal anaesthesia shivering

    PubMed Central

    Mittal, Geeta; Gupta, Kanchan; Katyal, Sunil; Kaushal, Sandeep

    2014-01-01

    Background and Aims: Dexmedetomidine (α2 adrenergic agonist) has been used for prevention of post anaesthesia shivering. Its use for the treatment of post-spinal anaesthesia shivering has not been evaluated. The aim of this study was to evaluate and compare the efficacy, haemodynamic and adverse effects of dexmedetomidine with those of tramadol, when used for control of post-spinal anaesthesia shivering. Methods: A prospective, randomised, and double-blind study was conducted in 50 American Society of Anaesthesiologists Grade I and II patients of either gender, aged between 18 and 65 years, scheduled for various surgical procedures under spinal anaesthesia. The patients were randomised in two groups of 25 patients each to receive either dexmedetomidine 0.5 μg/kg or tramadol 0.5 mg/kg as a slow intravenous bolus. Grade of shivering, onset of shivering, time for cessation of shivering, recurrence, response rate, and adverse effects were observed at scheduled intervals. Unpaired t-test was used for analysing the data. Results: Time taken for cessation of shivering was significantly less with dexmedetomidine when compared to tramadol. Nausea and vomiting was observed only in tramadol group (28% and; 20% respectively). There was not much difference in the sedation profile of both the drugs. Conclusion: We conclude that although both drugs are effective, the time taken for cessation of shivering is less with dexmedetomidine when compared to tramadol. Moreover, dexmedetomidine has negligible adverse effects, whereas tramadol is associated with significant nausea and vomiting. PMID:25024466

  18. Syrup formulations for post-tonsillectomy analgesia: a double-blind study comparing ibuprofen, aspirin and placebo.

    PubMed

    Parker, D A; Gibbin, K P; Noyelle, R M

    1986-09-01

    Post-tonsillectomy analgesia from ibuprofen, aspirin and placebo is compared in a double-blind study. The results are reported showing ibuprofen to have greater therapeutic benefit than placebo whereas aspirin did not. Methods of providing pain relief after tonsillectomy and the relative clinical merits of ibuprofen and aspirin are discussed. PMID:3531373

  19. Post-treatment of anaerobic reactor effluent using coagulation/oxidation followed by double filtration.

    PubMed

    Cavallini, Grasiele Soares; de Sousa Vidal, Carlos Magno; de Souza, Jeanette Beber; de Campos, Sandro Xavier

    2016-04-01

    This study evaluates the efficacy of a sanitary sewage treatment system, proposing post-treatment of the effluent generated by the upflow anaerobic sludge blanket UASB reactor, through a Fenton coagulation/oxidation ((ferric chloride (FC) or ferrous sulfate (FS) and peracetic acid (PAA)), followed by a double filtration system, composed of a gravel ascending drainage filter and a sand descending filter. Following the assessment of treatability, the system efficiency was evaluated using physicochemical and microbiological parameters. In all treatments performed in the pilot unit, total suspended solids (TSS) were completely removed, leading to a decrease in turbidity greater than 90% and close to 100% removal of total phosphorous. In the FC and PAA combination, the effluent was oxygenated prior to filtration, enabling a more significant removal of biochemical oxygen demand (BOD), which characterizes aerobic degradation even in a quick sand filter. The treatments carried out in the presence of the PAA oxidizing agent showed a more significant bleaching of the effluent. Concerning the microbiological parameters, the simultaneous use of PAA and FC contributed to the partial inactivation of the assessed microorganisms. A 65% recovery of the effluent was obtained with the proposed treatment system, considering the volume employed in filter backwashing. PMID:26611629

  20. Applying the Post-Modern Double ABC-X Model to Family Food Insecurity

    ERIC Educational Resources Information Center

    Hutson, Samantha; Anderson, Melinda; Swafford, Melinda

    2015-01-01

    This paper develops the argument that using the Double ABC-X model in family and consumer sciences (FCS) curricula is a way to educate nutrition and dietetics students regarding a family's perceptions of food insecurity. The Double ABC-X model incorporates ecological theory as a basis to explain family stress and the resulting adjustment and…

  1. "Hits" (Not "Discussion Posts") Predict Student Success in Online Courses: A Double Cross-Validation Study

    ERIC Educational Resources Information Center

    Ramos, Cheryl; Yudko, Errol

    2008-01-01

    The efficacy of individual components of an online course on positive course outcome was examined via stepwise multiple regression analysis. Outcome was measured as the student's total score on all exams given during the course. The predictors were page hits, discussion posts, and discussion reads. The vast majority of the variance of outcome was…

  2. Introduction of double amidoxime group by double post surface modification on poly(vinylbenzyl chloride) beads for higher amounts of organic dyes, As (V) and Cr (VI) removal.

    PubMed

    Ajmal, Muhammad; Demirci, Sahin; Uzun, Yusuf; Siddiq, Mohammad; Aktas, Nahit; Sahiner, Nurettin

    2016-05-15

    In this study, the synthesis of micron-sized poly(vinylbenzyl chloride) (p(VBC)) beads and subsequent conversion of the reactive chloromethyl groups to double amidoxime group containing moieties by post modification is reported. The prepared beads were characterized by SEM and FT-IR spectroscopy. The amidoximated p(VBC) beads were used as adsorbent for the removal of organic dyes, such as eosin y (EY) and methyl orange (MO), and heavy metals containing complex ions such as dichromate (Cr2O7(2-)) and arsenate (HAsO4(2)(-)) from aqueous media. The effect of the adsorbent dose on the percent removal, the effect of initial concentration of adsorbates on the adsorption rate and their amounts were also investigated. The Langmuir, Freundlich and Temkin adsorption isotherms were applied to the adsorption processes. The results indicated that the adsorption of both dichromate and arsenate ions obeyed the Langmuir adsorption model. Interestingly, it was found that the prepared beads were capable of removing significant amounts of arsenate and dichromate ions from tap and river (Sarıcay, Canakkale-Turkey) water. PMID:26930538

  3. High speed EUV using post processing and self-aligned double patterning as a speed enhancement technique

    NASA Astrophysics Data System (ADS)

    Wandell, Jerome; deVilliers, Anton; Huli, Lior; Biesemans, Serge; Nafus, Kathleen; Carcasi, Mike; Smith, Jeff; Hetzer, Dave; Higgins, Craig; Rastogi, Vinayak; Verduijn, Erik

    2014-04-01

    EUV is an ongoing industry challenge to adopt due to its current throughput limitations. The approach to improve throughput has primarily been through a significant focus on source power which has been a continuing challenge for the industry. The subject of this paper is to review and investigate the application of SADP (Self aligned double patterning) as a speed enhancing technique for EUV processing. A process with the potential of running a 16 nm self-aligned final etched pattern in less than 10mJ exposure range is proposed. Many of the current challenges with shot noise and resolution change significantly when SADP is used in conjunction with EUV. In particular, the resolution challenge for a 16nm HP final pattern type image changes to 32nm as an initial pattern requirement for the patterned CD. With this larger CD starting point, the burden of shot noise changes significantly and the ability for higher speed resist formulations to be used is enabled. Further resist candidates that may have not met the resolution requirements for EUV can also be evaluated. This implies a completely different operational set-point for EUV resist chemistry where the relaxation of both LER and CD together combined, give the resist formulation space a new target when EUV is used as a SADP tool. Post processing mitigation of LWR is needed to attain the performance of the final 16nm half pitch target pattern to align with the industry needs. If the original process flow at an 85W projected source power would run in the 50WPH range, then the flow proposed here would run in the <120WPH range. Although it is a double patterning technology, the proposed process still only requires a single pass through the EUV tool, This speed benefit can be used to offset the added costs associated with the double patterning process. This flow can then be shown to be an enabling approach for many EUV applications.

  4. Double White Dwarfs as Probes of Single and Binary Star Evolution

    NASA Astrophysics Data System (ADS)

    Andrews, Jeffrey John

    2016-01-01

    As the endpoints of stars less massive than roughly eight solar masses, the population of Galactic white dwarfs (WD) contain information about complex stellar evolution processes. Associated pairs of WDs add an extra degree of leverage; both WDs must have formed and evolved together. The work presented in this dissertation uses various populations of double WDs (DWD) to constrain evolution of both single and binary stars. One example is the set of low-mass WDs with unseen WD companions, which are formed through a dynamically-unstable mass loss process called the common envelope. To work toward a quantitative understanding of the common envelope, we develop and apply a Bayesian statistical technique to identify the masses of the unseen WD companions. We provide results which can be compared to evolutionary models and hence a deeper understanding of how binary stars evolve through a common envelope. The statistical technique we develop can be applied to any population of single-line spectroscopic binaries. Binaries widely separated enough that they avoid any significant interaction independently evolve into separate WDs that can be identified in photometric and astrometric surveys. We discuss techniques for finding these objects, known as wide DWDs. We present a catalog of 142 candidate wide DWDs, combining both previously detected systems and systems we identify in our searches in the Sloan Digital Sky Survey. Having been born at the same time, the masses and cooling ages of the WDs in wide DWDs, obtained with our spectroscopic follow-up campaign can be used to constrain the initial-final mass relation, which relates a main sequence star to the mass of the WD into which it will evolve. We develop a novel Bayesian technique to interpret our data and present our resulting constraints on this relation which are particularly strong for initial masses between two and four solar masses. During this process, we identified one wide DWD, HS 2220+2146, that was peculiar since

  5. Post unilateral lesion response biases modulate memory: crossed double dissociation of hemispheric specialisations.

    PubMed

    Braun, Claude M J; Delisle, Josée; Guimond, Anik; Daigneault, Rafaël

    2009-03-01

    We propose that what appears to be hemispheric specialisation in the memory domain, as indexed by effects of unilateral brain lesions, is to a great extent explainable as response bias: left hemisphere lesions result in an omissive response bias or error pattern whereas right hemisphere lesions result in a commissive response bias or error pattern. To test this prediction a group of 40 non-confabulatory cases with a verbal and non-verbal retention deficit (hypomnesia), subsequent to a unilateral lesion, was assembled from the literature. A group of non-amnesic cases with confabulation, paramnesia, false memories or memory-laden hallucination (dysfunctional hypermnesia), due to a unilateral lesion, was also assembled from the literature (N=72). Most of the hypomnesic patients had left hemisphere lesions (73%, p<.005, two tailed) while most of the hypermnesic patients had right hemisphere lesions (78%, p<.0005, two tailed). This crossed double dissociation held good despite statistical control of the lesion's locus within the hemisphere, its size or its aetiology, presence of aphasic symptoms, psychiatric comorbidity, the patient's age, gender, or hand preference, and several other potentially confounding variables. PMID:18991140

  6. Controlled DNA double-strand break induction in mice reveals post-damage transcriptome stability.

    PubMed

    Kim, Jeongkyu; Sturgill, David; Tran, Andy D; Sinclair, David A; Oberdoerffer, Philipp

    2016-04-20

    DNA double-strand breaks (DSBs) and their repair can cause extensive epigenetic changes. As a result, DSBs have been proposed to promote transcriptional and, ultimately, physiological dysfunction via both cell-intrinsic and cell-non-autonomous pathways. Studying the consequences of DSBs in higher organisms has, however, been hindered by a scarcity of tools for controlled DSB induction. Here, we describe a mouse model that allows for both tissue-specific and temporally controlled DSB formation at ∼140 defined genomic loci. Using this model, we show that DSBs promote a DNA damage signaling-dependent decrease in gene expression in primary cells specifically at break-bearing genes, which is reversed upon DSB repair. Importantly, we demonstrate that restoration of gene expression can occur independently of cell cycle progression, underlining its relevance for normal tissue maintenance. Consistent with this, we observe no evidence for persistent transcriptional repression in response to a multi-day course of continuous DSB formation and repair in mouse lymphocytesin vivo Together, our findings reveal an unexpected capacity of primary cells to maintain transcriptome integrity in response to DSBs, pointing to a limited role for DNA damage as a mediator of cell-autonomous epigenetic dysfunction. PMID:26687720

  7. Controlled DNA double-strand break induction in mice reveals post-damage transcriptome stability

    PubMed Central

    Kim, Jeongkyu; Sturgill, David; Tran, Andy D.; Sinclair, David A.; Oberdoerffer, Philipp

    2016-01-01

    DNA double-strand breaks (DSBs) and their repair can cause extensive epigenetic changes. As a result, DSBs have been proposed to promote transcriptional and, ultimately, physiological dysfunction via both cell-intrinsic and cell-non-autonomous pathways. Studying the consequences of DSBs in higher organisms has, however, been hindered by a scarcity of tools for controlled DSB induction. Here, we describe a mouse model that allows for both tissue-specific and temporally controlled DSB formation at ∼140 defined genomic loci. Using this model, we show that DSBs promote a DNA damage signaling-dependent decrease in gene expression in primary cells specifically at break-bearing genes, which is reversed upon DSB repair. Importantly, we demonstrate that restoration of gene expression can occur independently of cell cycle progression, underlining its relevance for normal tissue maintenance. Consistent with this, we observe no evidence for persistent transcriptional repression in response to a multi-day course of continuous DSB formation and repair in mouse lymphocytes in vivo. Together, our findings reveal an unexpected capacity of primary cells to maintain transcriptome integrity in response to DSBs, pointing to a limited role for DNA damage as a mediator of cell-autonomous epigenetic dysfunction. PMID:26687720

  8. Fully 3D Particle-in-Cell Simulation of Double Post-Hole Convolute on PTS Facility

    NASA Astrophysics Data System (ADS)

    Zhao, Hailong; Dong, Ye; Zhou, Haijing; Zou, Wenkang; Institute of Fluid Physics Collaboration; Institute of Applied Physics; Computational Mathematics Collaboration

    2015-11-01

    In order to get better understand of energy transforming and converging process during High Energy Density Physics (HEDP) experiments, fully 3D particle-in-cell (PIC) simulation code NEPTUNE3D was used to provide numerical approach towards parameters which could hardly be acquired through diagnostics. Cubic region (34cm × 34cm × 18cm) including the double post-hole convolute (DPHC) on the primary test stand (PTS) facility was chosen to perform a series of fully 3D PIC simulations, calculating ability of codes were tested and preliminary simulation results about DPHC on PTS facility were discussed. Taking advantages of 3D simulation codes and large-scale parallel computation, massive data (~ 250GB) could be acquired in less than 5 hours and clear process of current transforming and electron emission in DPHC were demonstrated with the help of visualization tools. Cold-chamber tests were performed during which only cathode electron emission was considered without temperature rise or ion emission, current loss efficiency was estimated to be 0.46% ~ 0.48% by comparisons between output magnetic field profiles with or without electron emission. Project supported by the National Natural Science Foundation of China (Grant No. 11205145, 11305015, 11475155).

  9. A novel mechanism for creating double pulsars

    NASA Technical Reports Server (NTRS)

    Sigurdsson, Steinn; Hernquist, Lars

    1992-01-01

    Simulations of encounters between pairs of hard binaries, each containing a neutron star and a main-sequence star, reveal a new formation mechanism for double pulsars in dense cores of globular clusters. In many cases, the two normal stars are disrupted to form a common envelope around the pair of neutron stars, both of which will be spun up to become millisecond pulsars. We predict that a new class of pulsars, double millisecond pulsars, will be discovered in the cores of dense globular clusters. The genesis proceeds through a short-lived double-core common envelope phase, with the envelope ejected in a fast wind. It is possible that the progenitor may also undergo a double X-ray binary phase. Any circular, short-period double pulsar found in the galaxy would necessarily come from disrupted disk clusters, unlike Hulse-Taylor class pulsars or low-mass X-ray binaries which may be ejected from clusters or formed in the galaxy.

  10. The Effect of Prophylactic Antibiotics on Post Laparoscopic Cholecystectomy Infectious Complications: A Double-Blinded Clinical Trial

    PubMed Central

    Darzi, Ali Asghar; Nikmanesh, Alieh; Bagherian, Farhad

    2016-01-01

    Background Laparoscopic cholecystectomy (LC) is one of the most common surgeries in laparoscopic surgery. Although, it is believed that LC has low-risk for post-operative infectious complications, the use of a prophylactic antibiotic is still controversial in elective LC. Objective To determine the impact of prophylactic antibiotics on postoperative infection complications in elective laparoscopic cholecystectomy. Methods In this double-blind, placebo-controlled, randomized, clinical trial, patients who were candidates for elective LC, from March 2012 to 2015, in four hospitals in Babol, Iran, were studied. Patients were allocated randomly to two groups, i.e., group C: Cefazolin (n = 182) and group P: placebo (n = 247). Group C received 1 g of Cefazolin 30 minutes before anesthesia and and then, six and 12 hours after anesthesia. Group P patients received 10 ml of isotonic sodium chloride solution. Age, gender, type of gallbladder diseases (stone, polyp, or hydrops), the length of post-operative hospitalization, frequency of gallbladder rupture, the duration of surgery, and the kinds of complications associated with infections were collected for each patient in the two groups. The data were analyzed by IBM-SPSS version 20, using the t-test and the chi-squared test, and a p-value < 0.05 was considered as significant. Results There were no significant differences between the two groups in terms of gender (C versus P: 18 (9.9%) male versus 22 (9%); p = 0.74), age (C versus P: 43.75 + 13.30 years versus 40.91 + 13.05; p = 0.20), and duration of surgery (C versus P: 34.97 ± 8.25 min versus 34.11 ± 8.39; p = 0.71). There were no significant differences between the two groups in the incidences of post-operative infection (C versus P: 3 (1.7%) versus 5 (2%); p = 0.99) and rupture of the gallbladder (C versus P: 14 (7.8%) versus 17 (6.8%); p = 0.85). No other post-operative systemic infectious complications (e.g., sepsis, pneumonia, or urinary tract infection) were found

  11. A double detached shell around a post-red supergiant: IRAS 17163-3907, the Fried Egg nebula

    NASA Astrophysics Data System (ADS)

    Lagadec, E.; Zijlstra, A. A.; Oudmaijer, R. D.; Verhoelst, T.; Cox, N. L. J.; Szczerba, R.; Mékarnia, D.; van Winckel, H.

    2011-10-01

    Context. We performed a mid-infrared imaging survey of evolved stars to study the dust distribution in circumstellar envelopes around these objects and to understand the mass-loss mechanism responsible for the formation of these envelopes better. During this survey, we resolved the circumstellar environment of IRAS 17163-3907 for the first time (hereafter IRAS 17163), which is one of the brightest objects in the mid-infrared sky, but is surprisingly not well studied. Aims: Our aim is to determine the evolutionary status of IRAS 17163 and study its circumstellar environment to understand its mass-loss history. Methods: We obtained diffraction-limited images of IRAS 17163 in the mid-infrared using VISIR on the VLT. Optical spectra of the object allowed us to determine its spectral type and estimate its distance through diffuse interstellar bands. Results: We show that IRAS 17163 is a post-red supergiant, possibly belonging to the rare class of yellow hypergiants, and is very similar to the well-studied object IRC +10420. Our mid-infrared images of IRAS 17163 are the first direct images of this bright mid-infrared source. These images clearly show a double dusty detached shell around the central star, caused by successive ejections of material on a timescale of the order of 400 years and a total circumstellar mass exceeding than 4 M⊙. This indicates that non-quiescent mass-loss occurs during this phase of stellar evolution. Based on observations made with the Very Large Telescope at Paranal Observatory under program 081.D-0130(A).Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofsica de Canarias.

  12. Double-core evolution. 5: Three-dimensional effects in the merger of a red giant with a dwarf companion

    NASA Technical Reports Server (NTRS)

    Terman, James L.; Taam, Ronald E.; Hernquist, Lars

    1994-01-01

    The evolution of the common envelope phase of a binary system consisting of a 4.67 solar mass red giant and a 0.94 solar mass dwarf is studied using smoothed particle hydrodynamics. We demonstrate that the three-dimensional effects associated with the gravitational tidal torques lead to a rapid decay of the orbit on timescales approximately less than 1 yr. The relative orbit of the two cores in the common envelope is initally eccentric and tends to circularize as the orbital separation of the two cores decreases. The angular momentum lost from the orbital motion is distributed throughout the common envelope, and the double core does not evolve to a state of co-rotation for the evolutionary time followed. The energy dissipated from the relative orbit and deposited in the common envelope results in the ejection of approximately 13% of the mass of the envelope. The mass is ejected in all directions, but there is a preference for mass ejection in the orbital plane of the binary system. For example, approximately 80% of the ejected mass lies within 30 deg of the binary orbital plane. Because gravitational forces are long range, most of the energy and angular momentum is imparted to a small fraction of the common envelope resulting in an efficiency of the mass ejection process of approximately 15%. The core of the red giant executes significant displacement with respect to the center of mass of the system and contributes nearly equally to the total energy dissipation rate during the latter phases of the evolution. The degree of departure from synchronism of the initial binary system can be an important property of the system which can affect the outcome of the common envelope phase.

  13. REPRODUCING THE OBSERVED ABUNDANCES IN RCB AND HdC STARS WITH POST-DOUBLE-DEGENERATE MERGER MODELS-CONSTRAINTS ON MERGER AND POST-MERGER SIMULATIONS AND PHYSICS PROCESSES

    SciTech Connect

    Menon, Athira; Herwig, Falk; Denissenkov, Pavel A.; Clayton, Geoffrey C.; Staff, Jan; Pignatari, Marco; Paxton, Bill

    2013-07-20

    The R Coronae Borealis (RCB) stars are hydrogen-deficient, variable stars that are most likely the result of He-CO WD mergers. They display extremely low oxygen isotopic ratios, {sup 16}O/{sup 18}O {approx_equal} 1-10, {sup 12}C/{sup 13}C {>=} 100, and enhancements up to 2.6 dex in F and in s-process elements from Zn to La, compared to solar. These abundances provide stringent constraints on the physical processes during and after the double-degenerate merger. As shown previously, O-isotopic ratios observed in RCB stars cannot result from the dynamic double-degenerate merger phase, and we now investigate the role of the long-term one-dimensional spherical post-merger evolution and nucleosynthesis based on realistic hydrodynamic merger progenitor models. We adopt a model for extra envelope mixing to represent processes driven by rotation originating in the dynamical merger. Comprehensive nucleosynthesis post-processing simulations for these stellar evolution models reproduce, for the first time, the full range of the observed abundances for almost all the elements measured in RCB stars: {sup 16}O/{sup 18}O ratios between 9 and 15, C-isotopic ratios above 100, and {approx}1.4-2.35 dex F enhancements, along with enrichments in s-process elements. The nucleosynthesis processes in our models constrain the length and temperature in the dynamic merger shell-of-fire feature as well as the envelope mixing in the post-merger phase. s-process elements originate either in the shell-of-fire merger feature or during the post-merger evolution, but the contribution from the asymptotic giant branch progenitors is negligible. The post-merger envelope mixing must eventually cease {approx}10{sup 6} yr after the dynamic merger phase before the star enters the RCB phase.

  14. Double-blind controlled trial to compare anti-inflammatory effects of tolmetin 2%, prednisolone 0.5%, and placebo in post-cataract extraction eyes.

    PubMed Central

    Smerdon, D L; Hung, S O; Akingbehin, T

    1986-01-01

    This paper compares the efficacy of tolmetin, prednisolone, and placebo (vehicle only) in controlling post-cataract extraction inflammation in a double-blind trial involving 120 patients. Seventeen patients were excluded from analysis. The results of the 103 patients analysed showed that 94% of the prednisolone treated group was judged to have been successfully treated as compared with 53% of the tolmetin treated group and 46% of the vehicle treated group. The differences between the prednisolone treated group and the other two groups were statistically significant (p less than 0.001). No statistical significance was found between the tolmetin and vehicle groups. PMID:3535872

  15. Granisetron versus ondansetron for post-operative nausea and vomiting prophylaxis in elective craniotomies for brain tumors: A randomized controlled double-blind study

    PubMed Central

    Gupta, Priyanka; Sabharwal, Nikki; Kale, Suniti; Gupta, Mayank; Gogia, Anoop R.

    2014-01-01

    Context: Post-operative nausea and vomiting (PONV) pose unique challenges in neurosurgical patients that warrant its study separate from other surgical groups. Setting and Design: This prospective, randomized, double-blind study was carried out to compare and to evaluate the efficacy and safety of three antiemetic combinations for PONV prophylaxis following craniotomy. Materials and Methods: A total of 75 anesthesiologist status I/II patients undergoing elective craniotomy for brain tumors were randomized into three groups, G, O and D, to receive single doses of dexamethasone 8 mg at induction with either granisetron 1 mg, ondansetron 4 mg or normal saline 2 ml at the time of dural closure respectively. Episodes of nausea, retching, vomiting and number of rescue antiemetic (RAE) were noted for 48 h post-operatively. Statistical Analysis: Analysis of variance with post-hoc significance and Chi-square test with fisher exact correction were used for statistical analysis. P <0.05 was considered to be significant and P < 0.001 as highly significant. Results: We found that the incidence and number of vomiting episodes and RAE required were significantly low in Group G and O compared with Group D; P < 0.05. However, incidence of nausea and retching were comparable among all groups. The anti-nausea and anti-retching efficacy of all the three groups was comparable. Conclusions: Single dose administration of granisetron 1 mg or ondansetron 4 mg at the time of dural closure with dexamethasone 8 mg provide an effective and superior prophylaxis against vomiting compared with dexamethasone alone without interfering with post-operative recovery and neurocognitive monitoring and hence important in post-operative neurosurgical care. PMID:25886108

  16. An ALMA View of the Complex Circumstellar Environment of the Post-AGB Object HD 101584

    NASA Astrophysics Data System (ADS)

    Olofsson, H.; Vlemmings, W.; Maercker, M.; Humphreys, E.; Lindqvist, M.; Nyman, L.; Ramstedt, S.

    2015-12-01

    We use 12CO, 13CO, and C18O J = 2-1 lines and 1.3 mm continuum ALMA observations to study the circumstellar evolution of the binary HD 101584, a post-AGB star and a low-mass companion, which is most likely a post-common-envelope-evolution system. It is inferred that the circumstellar medium has a bipolar hour-glass structure, seen almost pole-on, formed by an energetic, ≍ 150 km s-1, jet. Significant amount of material resides in an unresolved central region. It is proposed that the circumstellar morphology is related to an event which took place ≍ 500 yr ago, possibly a capture event where the companion spiraled in towards the AGB star. However, the kinetic energy of the accelerated gas exceeds the released orbital energy. Hence, the observed phenomenon does not match current common-envelope scenarios, and another process must augment, or even dominate, the ejection process.

  17. Post-irradiation chemical processing of DNA damage generates double-strand breaks in cells already engaged in repair

    PubMed Central

    Singh, Satyendra K.; Wang, Minli; Staudt, Christian; Iliakis, George

    2011-01-01

    In cells exposed to ionizing radiation (IR), double-strand breaks (DSBs) form within clustered-damage sites from lesions disrupting the DNA sugar–phosphate backbone. It is commonly assumed that these DSBs form promptly and are immediately detected and processed by the cellular DNA damage response (DDR) apparatus. This assumption is questioned by the observation that after irradiation of naked DNA, a fraction of DSBs forms minutes to hours after exposure as a result of temperature dependent, chemical processing of labile sugar lesions. Excess DSBs also form when IR-exposed cells are processed at 50°C, but have been hitherto considered method-related artifact. Thus, it remains unknown whether DSBs actually develop in cells after IR exposure from chemically labile damage. Here, we show that irradiation of ‘naked’ or chromatin-organized mammalian DNA produces lesions, which evolve to DSBs and add to those promptly induced, after 8–24 h in vitro incubation at 37°C or 50°C. The conversion is more efficient in chromatin-associated DNA, completed within 1 h in cells and delayed in a reducing environment. We conclude that IR generates sugar lesions within clustered-damage sites contributing to DSB formation only after chemical processing, which occurs efficiently at 37°C. This subset of delayed DSBs may challenge DDR, may affect the perceived repair kinetics and requires further characterization. PMID:21745815

  18. Japanese POEMS syndrome with Thalidomide (J-POST) Trial: study protocol for a phase II/III multicentre, randomised, double-blind, placebo-controlled trial

    PubMed Central

    Katayama, Kanako; Misawa, Sonoko; Sato, Yasunori; Sobue, Gen; Yabe, Ichiro; Watanabe, Osamu; Nishizawa, Masatoyo; Kusunoki, Susumu; Kikuchi, Seiji; Nakashima, Ichiro; Ikeda, Shu-ichi; Kohara, Nobuo; Kanda, Takashi; Kira, Jun-ichi; Hanaoka, Hideki; Kuwabara, Satoshi

    2015-01-01

    Introduction Polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome is a fatal systemic disorder associated with plasma cell dyscrasia and the overproduction of the vascular endothelial growth factor (VEGF). Recently, the prognosis of POEMS was substantially improved by introduction of therapeutic intervention for myeloma. However, no randomised clinical trial has been performed because of the rarity and severity of the disease. Methods and analysis The Japanese POEMS syndrome with Thalidomide (J-POST) Trial is a phase II/III multicentre, double-blinded, randomised, controlled trial that aims to evaluate the efficacy and safety of a 24-week treatment with thalidomide in POEMS syndrome, with an additional 48-week open-label safety study. Adults with POEMS syndrome who have no indication for transplantation are assessed for eligibility at 12 tertiary neurology centres in Japan. Patients who satisfy the eligibility criteria are randomised (1:1) to receive thalidomide (100–300 mg daily) plus dexamethasone (12 mg/m2 on days 1–4 of a 28-day cycle) or placebo plus dexamethasone. Both treatments were administered for 24 weeks (six cycles; randomised comparative study period). Patients who complete the randomised study period or show subacute deterioration during the randomised period participate in the subsequent 48-week open-label safety study (long-term safety period). The primary end point of the study is the reduction rate of serum VEGF levels at 24 weeks. Ethics and dissemination The protocol was approved by the Institutional Review Board of each hospital. The trial was notified and registered at the Pharmaceutical and Medical Devices Agency, Japan (No. 22-1716). The J-POST Trial is currently ongoing and is due to finish in August 2015. The findings of this trial will be disseminated through peer-reviewed publications and conference presentations and will also be disseminated to participants. Trial registration number

  19. Comparison of Efficacy of Clonidine versus Ondansetron for Prevention of Nausea and Vomiting Post Thyroidectomy: A Double Blind Randomized Controlled Trial

    PubMed Central

    Shilpa, Setty Nagendra Gupta; Hilda, Selvaraj Shanthini

    2015-01-01

    Background and Aim Postoperative nausea vomiting (PONV) is the most common symptom in patients post thyroidectomy. Literature search shows conflicting results regarding use of clonidine in PONV prophylaxis. We undertook this randomized controlled double blind trial to compare the efficacy of clonidine with dexamethasone versus ondansetron with dexamethasone for PONV prophylaxis in these patients. Materials and Methods In this prospective study, 60 consecutive patients posted for thyroidectomy from August 2013 to July 2014, were randomly assigned to two groups, ondansetron (N= 30) (Group A) and clonidine (N= 30) (Group B). Patients received either oral ondansetron 8mg or oral clonidine 150μg as premedication. At the end of surgery, both groups received dexamethasone 8mg intravenously. They were monitored for occurrence of PONV and sore throat for next 24 h. Ramsay sedation scores and total time of analgesia was noted. The primary end point was incidence of PONV in post operative for 24 h. Pearson’s chi square test and Students t tests were performed using SPSS for windows version 20 (SPSS Inc., Chicago, IL). Results Baseline characteristics of patients were comparable. A higher proportion of patients in clonidine group developed PONV than ondansetron (36.7% vs 30%; p=0.03). Clonidine group patients experienced early nausea and vomiting (1-2hrs of postoperative period), compared to ondansetron group patients (6-12 h). Ramsay sedation scores at arrival were higher in clonidine group compared to ondansetron group (2.1 ± 0.3 versus 2.0; p=0.003). Total time of analgesia was higher with use of clonidine than ondansetron (919.5 ± 622 mins versus 642 ± 631 mins; p=0.09). Moderate sore throat was seen in 2 out of 30 patients in both groups. No major adverse events were observed in either group. Conclusion Ondansetron with dexamethasone group was more effective in controlling PONV after thyroidectomy compared to clonidine with dexamethasone group. However, ramsay

  20. Fluoroscopic Caudal Epidural Injections in Managing Post Lumbar Surgery Syndrome: Two-Year Results of a Randomized, Double-Blind, Active-Control Trial

    PubMed Central

    Manchikanti, Laxmaiah; Singh, Vijay; Cash, Kimberly A.; Pampati, Vidyasagar; Datta, Sukdeb

    2012-01-01

    Study Design: A randomized, active control, double-blind trial. Objective: To evaluate the effectiveness of fluoroscopically directed caudal epidural injections with or without steroids in managing chronic low back and lower extremity pain secondary to post lumbar surgery syndrome. Summary of Background Data: There is a paucity of evidence concerning caudal epidural injections for managing chronic persistent low back pain with or without lower extremity pain caused by post lumbar surgery syndrome. Methods: This active control randomized study included 140 patients with 70 patients in each group. Group I received 0.5% lidocaine, 10 mL; Group II received 9 mL of 0.5% lidocaine mixed with 1 mL of 6 mg of nonparticulate betamethasone. The multiple outcome measures included the numeric rating scale, the Oswestry Disability Index 2.0, employment status, and opioid intake with assessments at 3, 6, 12, 18, and 24 months posttreatment. Primary outcome was defined as at least 50% improvement in pain and Oswestry Disability Index scores. Patients with a positive response to the first 2 procedures with at least 3 weeks of relief were considered to be successful. All others were considered as failures. Results: Overall in Group I, 53% and 47% of the patients and in Group II, 59% and 58% of the patients, showed significant improvement with reduction in pain scores and disability index at 12 months and 24 months. In contrast, in the successful groups, significant pain relief and improvement in function were observed in 70% and 62% of Group I at one and 2 years; in 75% and 69% of Group II at one and 2 years. The results in the successful group showed that at the end of the first year patients experienced approximately 38 weeks of relief and at the end of 2 years Group I had 62 weeks and Group II had 68 weeks of relief. Overall total relief for 2 years was 48 weeks in Group I and 54 weeks in Group II. The average procedures in the successful groups were at 4 in one year and 6 at

  1. New Insights into the Post-Translational Regulation of DNA Damage Response and Double-Strand Break Repair in Caenorhabditis elegans

    PubMed Central

    Kim, Hyun-Min; Colaiácovo, Monica P.

    2015-01-01

    Although a growing number of studies have reported the importance of SUMOylation in genome maintenance and DNA double-strand break repair (DSBR), relevant target proteins and how this modification regulates their functions are yet to be clarified. Here, we analyzed SUMOylation of ZTF-8, the homolog of mammalian RHINO, to test the functional significance of this protein modification in the DSBR and DNA damage response (DDR) pathways in the Caenorhabditis elegans germline. We found that ZTF-8 is a direct target for SUMOylation in vivo and that its modification is required for DNA damage checkpoint induced apoptosis and DSBR. Non-SUMOylatable mutants of ZTF-8 mimic the phenotypes observed in ztf-8 null mutants, including reduced fertility, impaired DNA damage repair, and defective DNA damage checkpoint activation. However, while mutants for components acting in the SUMOylation pathway fail to properly localize ZTF-8, its localization is not altered in the ZTF-8 non-SUMOylatable mutants. Taken together, these data show that direct SUMOylation of ZTF-8 is required for its function in DSBR as well as DDR but not its localization. ZTF-8’s human ortholog is enriched in the germline, but its meiotic role as well as its post-translational modification has never been explored. Therefore, our discovery may assist in understanding the regulatory mechanism of this protein in DSBR and DDR in the germline. PMID:25819793

  2. A Randomised, Double-Blind, Placebo-Controlled Trial of Actovegin in Patients with Post-Stroke Cognitive Impairment: ARTEMIDA Study Design

    PubMed Central

    Guekht, Alla; Skoog, Ingmar; Korczyn, Amos D.; Zakharov, Vladimir; Eeg, Martin; Vigonius, Ulf

    2013-01-01

    Background No drug treatment to date has shown convincing clinical evidence of restoring cognitive function or preventing further decline after stroke. The ongoing ARTEMIDA study will evaluate the efficacy and safety of Actovegin for the symptomatic treatment of post-stroke cognitive impairment (PSCI) and will explore whether Actovegin has any disease-modifying effect by assessing whether any changes are sustained after treatment. Design ARTEMIDA is a 12-month, multicentre trial in patients (planned a total of 500, now recruited) with cognitive impairment following ischaemic stroke. The study consists of a baseline screening (≤7 days after stroke), after which eligible patients are randomised to Actovegin (2,000 mg/day for up to 20 intravenous infusions followed by 1,200 mg/day orally) or placebo for a 6-month double-blind treatment period. Patients will be followed up for a further 6 months, during which time they will be treated in accordance with standard clinical practice. The primary study endpoint is change from baseline in the Alzheimer's Disease Assessment Scale, cognitive subscale, extended version. Secondary outcomes include: Montreal Cognitive Assessment; dementia diagnosis (ICD-10); National Institutes of Health Stroke Scale; Barthel Index; EQ-5D; Beck Depression Inventory, version II, and safety. Conclusion There is a clear need for effective treatments for PSCI. ARTEMIDA should provide important insights into the use of a novel drug therapy for PSCI. PMID:24516413

  3. Veno-venous extracorporeal membrane oxygenation using a double-lumen bi-caval cannula for severe respiratory failure post total artificial heart implantation.

    PubMed

    Miessau, J; Yang, Q; Unai, S; Entwistle, J W C; Cavarocchi, N C; Hirose, H

    2015-07-01

    We report a unique utilization of a double-lumen, bi-caval Avalon cannula for veno-venous (VV) extracorporeal membrane oxygenation (ECMO) during placement of a total artificial heart (TAH, SynCardia, Tucson, AZ). A 22-year-old female with post-partum cardiomyopathy was rescued on veno-arterial (VA) ECMO because of cardiogenic shock. The inability to wean ECMO necessitated implantation of the TAH as a bridge to transplant. In addition, the patient continued to have respiratory failure and concomitant VV ECMO was planned with the implant. During TAH implantation, the Avalon cannula was placed percutaneously from the right internal jugular vein into the inferior vena cava (IVC) under direct vision while the right atrium was open. During VV ECMO support, adequate flows on both ECMO and TAH were maintained without adverse events. VV ECMO was discontinued, without reopening the chest, once the patient's respiratory failure improved. However, the patient subsequently developed a profound respiratory acidosis and required VV ECMO for CO2 removal. The Avalon cannula was placed in the femoral vein to avoid accessing the internal jugular vein and risking damage to the TAH. The patient's oxygenation eventually improved and the cannula was removed at the bedside. The patient was supported for 22 days on VV ECMO and successfully weaned from the ventilator prior to her orthotropic heart transplantation. PMID:25239275

  4. Effect of NR-Salacia on post-prandial hyperglycemia: A randomized double blind, placebo-controlled, crossover study in healthy volunteers

    PubMed Central

    Koteshwar, Pravina; Raveendra, Kadur Ramamurthy; Allan, Joseph Joshua; Goudar, Krishnagouda Shankargouda; Venkateshwarlu, Kudiganti; Agarwal, Amit

    2013-01-01

    Background: Salacia chinensis (S. chinensis) is widely distributed in India and Sri Lanka. Most of the species of genus Salacia are known to have effects on blood glucose levels; however, the effects of S. chinensis on glucose levels are seldom reported. Objective: To evaluate the oral hypoglycemic activity of NR- Salacia (1000 mg extract of S. chinensis) in healthy adults. Materials and Methods: Randomized, double-blind, placebo-controlled, cross-over study was conducted in healthy volunteers. Single dose of NR-Salacia (1000 mg extract of Salacia chinensis) and placebo were administered before carbohydrate-rich diet. A 6-point plasma glucose profile was performed at different time intervals up to 180 min. Results: NR-Salacia treatment significantly lowered plasma glucose level at 90 min, and the percentage reduction in glucose concentration was found to be 13.32 as compared to placebo group. A 33.85% decrease in the plasma glucose positive incremental area under curve (AUC) (0 to 180 min) was observed in comparison to placebo. No adverse events were recorded throughout the study period, except for some mild cases of abdominal discomforts like cramping and distention, vomiting, and headache in both placebo and NR-Salacia-treated groups. Conclusion: The study findings revealed that NR-Salacia lowered the post-prandial plasma glucose levels after a carbohydrate-rich meal and can be used as an oral hypoglycemic agent. PMID:24124287

  5. Suicidal Thoughts and Reasons for Living in Hospitalized Patients With Severe Depression: Post-Hoc Analyses of a Double-Blind Randomized Trial of Duloxetine

    PubMed Central

    Desaiah, Durisala; Raskin, Joel; Cairns, Victoria; Brecht, Stephan

    2014-01-01

    Objective: To evaluate suicidal thoughts in relationship to depressive symptom severity and reasons for living in patients hospitalized for major depressive disorder (MDD). Method: A post hoc analysis was conducted of a randomized, double-blind, parallel-group trial involving hospitalized patients with MDD (DSM-IV criteria) who received duloxetine 60 mg once daily or duloxetine 60 mg twice daily for 8 weeks. After 4 weeks, the dose for nonresponders receiving 60 mg once daily could be increased to 60 mg twice daily (double-blind). The study was conducted between February 9, 2007, and August 26, 2008 at 43 centers in 4 countries across Europe and South Africa. Suicidal thoughts were assessed with Montgomery-Asberg Depression Rating Scale (MADRS) item 10, depression severity was assessed with the 6-item Hamilton Depression Rating Scale and the Clinical Global Impressions–Severity of Illness scale, and protective factors were assessed with the patient-rated Reasons for Living Inventory (RFL) assessing 6 domains. Descriptive statistics, correlation, and linear regression analysis were performed. Results: At baseline, patients (N = 336) had varying severity of suicidal thoughts: 18% had a score ≥ 4. The proportion of patients with a score ≥ 4 decreased to 7% at week 1 and 1% at week 8 of treatment. The RFL scores at baseline were lower in patients with higher baseline suicidal thoughts and increased significantly during treatment (P < .0001). A regression model revealed that only 16% of variance in baseline total RFL score is explained by the different MADRS items. Eight patients had suicidal behavior or ideation recorded as an adverse event during the study; no consistent pattern was found in the different psychometric scores either at baseline or at the visit preceding the suicidal behavior/ideation. Conclusions: Suicidality rapidly decreased in hospitalized patients with severe depression treated with duloxetine. The RFL scores were low at baseline but

  6. The effect of herbal extract (EstroG-100) on pre-, peri- and post-menopausal women: a randomized double-blind, placebo-controlled study.

    PubMed

    Chang, Albert; Kwak, Bo-Yeon; Yi, Kwontaek; Kim, Jae Soo

    2012-04-01

    This clinical research study was designed to evaluate the efficacy of a new herbal product, EstroG-100, containing a mixture of standardized extracts of Cynanchum wilfordii, Phlomis umbrosa and Angelica gigas, on menopausal symptoms. This randomized double-blind, placebo-controlled trial was performed for 12 weeks with 64 pre-, peri- and postmenopausal White Hispanic, White non-Hispanic and African American women who were randomly allocated to either the EstroG-100 group (n = 31) or the placebo group (n =  33). Primary end-points were the mean change in scores of the Kupperman menopause index (KMI) that evaluates 11 symptoms, and the mean change in scores of vaginal dryness. The mean KMI score was significantly reduced in the EstroG-100 group from 29.5 ± 7.4 at baseline to 11.3 ± 5.8 (p < 0.01) compared with change of the placebo group (29.2 ± 6.6 at baseline vs 23.7 ± 7.7 at week 12). The constituting symptoms of vasomotor, paresthesia, insomnia, nervousness, melancholia, vertigo, fatigue and rheumatic pain were significantly improved in the EstroG-100 group in comparison with the placebo group (p < 0.05). Statistically significant improvement in vaginal dryness in the EstroG-100 group was also observed compared with that of the placebo group (p < 0.05). In conclusion, EstroG-100 significantly improved the menopausal symptoms of pre-, peri- and post-menopausal women without weight gain or any serious side effects. PMID:21887807

  7. Effect of lurasidone dose on cognition in patients with schizophrenia: post-hoc analysis of a long-term, double-blind continuation study.

    PubMed

    Harvey, Philip D; Siu, Cynthia O; Ogasa, Masaaki; Loebel, Antony

    2015-08-01

    We previously reported that treatment with 160mg/d of lurasidone improved cognitive performance in a manner superior to placebo, quetiapine XR 600mg/d, and lurasidone 80mg/d, based on a 6-week randomized trial of patients with an acute exacerbation of schizophrenia. The objective of this post-hoc analysis was to explore the cognitive and functional performance of patients whose final doses of lurasidone were 40/80mg/d, 120mg/d, and 160mg/d compared to quetiapine XR 200-800mg/d (QXR) during a 6-month, double-blind continuation study that followed a short-term trial. Subjects who received final doses of lurasidone 120mg/d (n=77) and 160mg/d (n=49) showed significantly greater improvement in overall cognitive performance compared to QXR (n=85) at week 32 (month 6 of the extension study), while those on last doses of 40/80mg/d (n=25) showed a trend towards significance at week 32. Mean changes in neurocognitive composite z-score from pre-treatment baseline were significant for the 3 lurasidone final dose groups at both weeks 19 and 32, with composite change scores of z=1.53, z=1.43, and z=1.34 for the lurasidone 40/80mg/d, 120mg/d, and 160mg/d, respectively, at week 32. In contrast, the composite change score was not statistically significant in the overall quetiapine group (z=0.46), with none of the individual quetiapine doses showing any significant improvement. Functional capacity scores improved in all treatment groups. Our findings indicate improved cognitive performance in patients treated with each of the flexible doses of lurasidone 40-160mg/d, compared to quetiapine XR 200-800mg/d. All doses of lurasidone were superior to all doses of quetiapine for cognitive performance. PMID:26117157

  8. Wrinkle reduction in post-menopausal women consuming a novel oral supplement: a double-blind placebo-controlled randomized study

    PubMed Central

    Jenkins, G; Wainwright, L J; Holland, R; Barrett, K E; Casey, J

    2014-01-01

    Synopsis Objective The maintenance of youthful skin appearance is strongly desired by a large proportion of the world's population. The aim of the present study was therefore to evaluate the effect on skin wrinkling, of a combination of ingredients reported to influence key factors involved in skin ageing, namely inflammation, collagen synthesis and oxidative/UV stress. A supplemented drink was developed containing soy isoflavones, lycopene, vitamin C and vitamin E and given to post-menopausal women with a capsule containing fish oil. Method We have performed a double-blind randomized controlled human clinical study to assess whether this cocktail of dietary ingredients can significantly improve the appearance of facial wrinkles. Results We have shown that this unique combination of micronutrients can significantly reduce the depth of facial wrinkles and that this improvement is associated with increased deposition of new collagen fibres in the dermis. Conclusion This study demonstrates that consumption of a mixture of soy isoflavones, lycopene, vitamin C, vitamin E and fish oil is able to induce a clinically measureable improvement in the depth of facial wrinkles following long-term use. We have also shown, for the first time with an oral product, that the improvement is associated with increased deposition of new collagen fibres in the dermis. Résumé Objectif Le maintien de l'apparence d'une peau jeune est vivement souhaité par une grande proportion de la population mondiale. L'objectif de la présente étude était donc d'évaluer l'effet sur les rides de la peau, d'une combinaison d'ingrédients rapportés à influer sur les facteurs clés impliqués dans le vieillissement de la peau, à savoir l'inflammation, la synthèse du collagène et le stress oxydatif / UV. Une boisson supplémentée a été élaborée contenant des isoflavones de soja, le lycopène, la vitamine C et la vitamine E et donnée aux femmes ménopausées avec une capsule contenant de l

  9. Effect of low-level laser therapy on the post-surgical inflammatory process after third molar removal: study protocol for a double-blind randomized controlled trial

    PubMed Central

    2013-01-01

    Background Low-level laser therapy (LLLT) has been shown to modulate the inflammatory process without adverse effects , by reducing pain and swelling and promoting the repair of damaged tissues. Because pain, swelling and muscle spasm are complications found in virtually all patients following oral surgery for the removal of impacted teeth, this model has been widely used to evaluate the effects of LLLT on the inflammatory process involving bone and, connective tissue and the muscles involved in mastication. Methods/Design After meeting the eligibility criteria, 60 patients treated at a Specialty Dental Center for the removal of impacted lower third molars will be randomly divided into five groups according to the type of laser therapy used at the end of surgery (intraoral irradiation with 660 nm laser; extraoral irradiation with 660 nm laser; intraoral irradiation with 808 nm laser; extraoral irradiation with 808 nm laser and no irradiation). To ensure that patients are blinded to the type of treatment they are receiving, the hand piece of the laser apparatus will be applied both intraorally and extraorally to all participants, but the device will be turned on only at the appropriate time, as determined by the randomization process. At 2 and 7 days after surgery, the patients will be evaluated by three blinded evaluators who will measure of swelling, mouth opening (muscle spasm evaluation) and pain (using two different pain scales). The 14-item Oral Health Impact Profile (OHIP-14) will be used to assess QOL. All data will be analyzed with respect to the normality of distribution using the Shapiro-Wilk test. Statistically significant differences between the experimental groups will be determined using analysis of variance, followed by a suitable post hoc test, when necessary. The significance level will be set at α = 0.05. Discussion The lack of standardization in studies with regard to the samples, methods and LLLT parameters complicates the

  10. Intravenous dexamethasone versus ketamine gargle versus intravenous dexamethasone combined with ketamine gargle for evaluation of post-operative sore throat and hoarseness: A randomized, placebo-controlled, double blind clinical trial

    PubMed Central

    Safavi, Mohammadreza; Honarmand, Azim; Fariborzifar, Arghavan; Attari, Mohammadali

    2014-01-01

    Background: Sore throat and hoarseness are the most frequent subjective complaints after tracheal intubation for general anesthesia. We conducted a prospective, randomized, double-blind, placebo controlled study to evaluate the efficacy of intravenous (IV) dexamethasone plus ketamine gargle for reducing the incidence and severity of post-operative sore throat (POST) and hoarseness. Materials and Methods: 140 patients (aged 16-65 year) scheduled for elective surgery were enrolled. Patients were randomly allocated into four groups of 35 subjects each: Group K, gargled 40 mg ketamine in 30 ml saline; Group D, were infused 0.2 mg/kg IV dexamethasone; Group KD, gargled 40 mg ketamine in 30 ml saline plus 0.2 mg/kg IV dexamethasone; Group P (placebo) that received saline (gargle and IV). POST was graded at 0, 2, 4, 8, 16 and 24 h after operation on a four-point scale (0-3). Results: The incidence and severity of POST were significantly lower in Group KD, compared with the other groups at all times after tracheal extubation for up to 24 h (P < 0.05). Also the incidence and severity of hoarseness were significantly lower in each Groups of KD and K and D compared with group placebo (P < 0.05). Conclusion: The prophylactic use of 0.2 mg/kg of IV dexamethasone plus ketamine gargle significantly reduced the incidence and severity of POST compared with using each of these drugs alone or using placebo. PMID:25371869

  11. Effect of ondansetron on prevention of post-induction hypotension in elderly patients undergoing general anesthesia: A randomized, double-blind placebo-controlled clinical trial

    PubMed Central

    Golparvar, Mohammad; Saghaei, Mahmoud; Saadati, Mohammad Ali; Farsaei, Shadi

    2015-01-01

    Background: Elderly patients are susceptible to post-induction hypotension. Volume loading and vasopressors for prevention of hypotension in elderly patients may increase perioperative cardiovascular risks. Ondansetron by blocking Bezold–Jarisch reflex (BJR) through inhibition of serotonin receptors has been effective in the prevention of post-spinal hypotension, and bradycardia. Bradycardia frequently accompanies post-induction hypotension in elderly patients, which signifies a possible preventing role for ondansetron. No previous study has evaluated the prophylactic effects of ondansetron for the prevention of post-induction hypotension. Materials and Methods: In this randomized placebo-controlled clinical trial, ondansetron 4 mg was given intravenously to 65 elderly patients, 20 min before induction of general anesthesia, and the rate of post-induction hypotension defined as 25% or more reduction in mean arterial blood pressure, compared with a placebo groups. Results: A total of 114 patients completed the study (58 in ondansetron and 56 in the placebo group). Proportions of post-induction hypotension were 9 (16%) and 25 (45%) in ondansetron and placebo groups, respectively, (P = 0.001). Forty-five patients (40%) developed bradycardia. Rates of bradycardia were not significantly different between two groups. Conclusions: The results of this study show the effectiveness of intravenous ondansetron for prevention of post-induction hypotension in elderly patients. The mechanism of this effect largely is unknown. Role of ondansetron for prevention of post-induction hypotension may not fully understandable by its interaction with BJR, as has been shown in post-spinal hypotension. PMID:26543450

  12. A double-blind, placebo-controlled intervention trial of 3 and 10 mg sublingual melatonin for post-concussion syndrome in youths (PLAYGAME): study protocol for a randomized controlled trial

    PubMed Central

    2014-01-01

    Background By the age of sixteen, one in five children will sustain a mild traumatic brain injury also known as concussion. Our research found that one in seven school children with mild traumatic brain injury suffer post-concussion syndrome symptoms for three months or longer. Post-concussion syndrome is associated with significant disability in the child and his/her family and yet there are no evidence-based medical treatments available. Melatonin has several potential mechanisms of action that could be useful following mild traumatic brain injury, including neuroprotective effects. The aim of this study is to determine if treatment with melatonin improves post-concussion syndrome in youths following mild traumatic brain injury. Our hypothesis is that treatment of post-concussion syndrome following mild traumatic brain injury with 3 or 10 mg of sublingual melatonin for 28 days will result in a decrease in post-concussion syndrome symptoms compared with placebo. Methods/Design Ninety-nine youths with mild traumatic brain injury, aged between 13 and 18 years, who are symptomatic at 30 days post-injury will be recruited. This study will be conducted as a randomized, double blind, placebo-controlled superiority trial of melatonin. Three parallel treatment groups will be examined with a 1:1:1 allocation: sublingual melatonin 3 mg, sublingual melatonin 10 mg, and sublingual placebo. Participants will receive treatment for 28 days. The primary outcome is a change on the Post-Concussion Symptom Inventory (Parent and Youth). The secondary outcomes will include neurobehavioral function, health-related quality of life and sleep. Neurophysiological and structural markers of change, using magnetic resonance imaging techniques and transcranial magnetic stimulation, will also be investigated. Discussion Melatonin is a safe and well-tolerated agent that has many biological properties that may be useful following a traumatic brain injury. This study will determine whether it is a

  13. A Systems Biology Approach Investigating the Effect of Probiotics on the Vaginal Microbiome and Host Responses in a Double Blind, Placebo-Controlled Clinical Trial of Post-Menopausal Women

    PubMed Central

    Bisanz, Jordan E.; Seney, Shannon; McMillan, Amy; Vongsa, Rebecca; Koenig, David; Wong, LungFai; Dvoracek, Barbara; Gloor, Gregory B.; Sumarah, Mark; Ford, Brenda; Herman, Dorli; Burton, Jeremy P.; Reid, Gregor

    2014-01-01

    A lactobacilli dominated microbiota in most pre and post-menopausal women is an indicator of vaginal health. The objective of this double blinded, placebo-controlled crossover study was to evaluate in 14 post-menopausal women with an intermediate Nugent score, the effect of 3 days of vaginal administration of probiotic L. rhamnosus GR-1 and L. reuteri RC-14 (2.5×109 CFU each) on the microbiota and host response. The probiotic treatment did not result in an improved Nugent score when compared to when placebo. Analysis using 16S rRNA sequencing and metabolomics profiling revealed that the relative abundance of Lactobacillus was increased following probiotic administration as compared to placebo, which was weakly associated with an increase in lactate levels. A decrease in Atopobium was also observed. Analysis of host responses by microarray showed the probiotics had an immune-modulatory response including effects on pattern recognition receptors such as TLR2 while also affecting epithelial barrier function. This is the first study to use an interactomic approach for the study of vaginal probiotic administration in post-menopausal women. It shows that in some cases multifaceted approaches are required to detect the subtle molecular changes induced by the host to instillation of probiotic strains. Trial Registration ClinicalTrials.gov NCT02139839 PMID:25127240

  14. Pre- and Post-Head Processing for Single- and Double-Scrambled Sentences of a Head-Final Language as Measured by the Eye Tracking Method

    ERIC Educational Resources Information Center

    Tamaoka, Katsuo; Asano, Michiko; Miyaoka, Yayoi; Yokosawa, Kazuhiko

    2014-01-01

    Using the eye-tracking method, the present study depicted pre- and post-head processing for simple scrambled sentences of head-final languages. Three versions of simple Japanese active sentences with ditransitive verbs were used: namely, (1) SO[subscript 1]O[subscript 2]V canonical, (2) SO[subscript 2]O[subscript 1]V single-scrambled, and (3)…

  15. Preoperative evaluation of stage T3, central-type non-small cell lung cancer with double sleeve lobectomy under complete video-assisted thoracoscopic surgery using spiral computed tomography post-processing techniques

    PubMed Central

    Guan, Yubao; Huang, Jun; Xia, Tingting; You, Xiaoting; He, Jiaxi

    2016-01-01

    Background To investigate the estimated value of spiral computed tomography (CT) post-processing techniques in preoperative stage T3, central-type non-small cell lung cancer (NSCLC) with double sleeve lobectomy under complete video-assisted thoracoscopic surgery (c-VATS). Methods Preoperative clinical date and CT reconstructed data of 10 patients who underwent double sleeve lobectomy with upper lobe stage T3, central-type NSCLC were retrospectively analysed and compared to surgical pathological results and cross-sectional CT data. The diagnostic criterions of tumour invasion of pulmonary artery and bronchus were divided into five grades, which included estimation of upper lobe pulmonary arteries and bronchi (40 branches, respectively). Results The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of cross-sectional CT images of pulmonary artery tumour invasion were 78.57%, 58.33%, 81.48%, 53.85%, and 72.50%, respectively, while the respective values for CT reconstructed images were 93.55%, 87.50%, 96.67%, 70.00%, and 90.00%, showing statistical significance (χ2=4.021, P=0.045). Similarly, the evaluate, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of cross-sectional CT images of bronchial tumour invasion were 82.76%, 45.45%, 80.00%, 50.00%, and 72.50%, respectively, while the respective values for CT reconstructed images were 97.06%, 66.67%, 94.29%, 80.00%, 92.50%; these results were also statistically significant (χ2=5.541, P=0.019). Conclusions The sensitivity, specificity, and diagnostic accuracy of the spiral CT post-processing techniques were better than cross-sectional CT images in estimating the extent of tumour invasion in the pulmonary arteries and bronchi of central-type NSCLC. CT post-processing techniques are essential tools in preoperative examination and operative method selection of central-type lung cancer with double sleeve

  16. Total Iron Absorption by Young Women from Iron-Biofortified Pearl Millet Composite Meals Is Double That from Regular Millet Meals but Less Than That from Post-Harvest Iron-Fortified Millet Meals123

    PubMed Central

    Cercamondi, Colin I.; Egli, Ines M.; Mitchikpe, Evariste; Tossou, Felicien; Zeder, Christophe; Hounhouigan, Joseph D.; Hurrell, Richard F.

    2013-01-01

    Iron biofortification of pearl millet (Pennisetum glaucum) is a promising approach to combat iron deficiency (ID) in the millet-consuming communities of developing countries. To evaluate the potential of iron-biofortified millet to provide additional bioavailable iron compared with regular millet and post-harvest iron-fortified millet, an iron absorption study was conducted in 20 Beninese women with marginal iron status. Composite test meals consisting of millet paste based on regular-iron, iron-biofortified, or post-harvest iron-fortified pearl millet flour accompanied by a leafy vegetable sauce or an okra sauce were fed as multiple meals for 5 d. Iron absorption was measured as erythrocyte incorporation of stable iron isotopes. Fractional iron absorption from test meals based on regular-iron millet (7.5%) did not differ from iron-biofortified millet meals (7.5%; P = 1.0), resulting in a higher quantity of total iron absorbed from the meals based on iron-biofortified millet (1125 vs. 527 μg; P < 0.0001). Fractional iron absorption from post-harvest iron-fortified millet meals (10.4%) was higher than from regular-iron and iron-biofortified millet meals (P < 0.05 and P < 0.01, respectively), resulting in a higher quantity of total iron absorbed from the post-harvest iron-fortified millet meals (1500 μg; P < 0.0001 and P < 0.05, respectively). Results indicate that consumption of iron-biofortified millet would double the amount of iron absorbed and, although fractional absorption of iron from biofortification is less than that from fortification, iron-biofortified millet should be highly effective in combatting ID in millet-consuming populations. PMID:23884388

  17. Design for Double Rainbow

    ERIC Educational Resources Information Center

    Thomas, Lisa Carlucci

    2011-01-01

    Rare is the inspirational, spontaneous, transformative moment shared among 20 million people. In the summer of 2010, people around the world were moved by the sighting of a double rainbow--almost a triple rainbow--"all the way across the sky" in Yosemite National Park. Caught on video and posted to by YouTube by Paul Vasquez in January 2010, the…

  18. Comparison of pre- vs. post-incisional caudal bupivacaine for postoperative analgesia in unilateral pediatric herniorrhaphy: A double-blind randomized clinical trial

    PubMed Central

    Sajedi, Parvin; Yaraghi, Ahmad; Zadeh, Mohammad Taher Dehdari

    2011-01-01

    Introduction: This study was designed to evaluate the pre- vs. post-incisional analgesic efficacy of bupivacaine administered caudally in children undergoing unilateral hernia repair. Methods: Fifty children aged 6 months to 6 years were included in the study. Children were divided blindly between the two groups to receive pre- vs. post-incisional caudal bupivacaine. The preincisional group received 1 ml/kg of 0.125% bupivacaine caudally after induction of anesthesia and the postincisional group received the same dose caudally at the end of surgery. Heart rate, SaO2, end tidal CO2, and noninvasive arterial blood pressure were recorded every 10 min. The duration of surgery, extubation time, and duration of recovery period were also recorded. The pain scores were measured with using an Oucher chart in the recovery room, 2, 4, 6, 12, and 24 h after surgery. Time to first analgesia, numbers of supplementary analgesics required by each child in a 24-h period and total analgesic consumptions were recorded. Any local and systemic complications were recorded. Quantitative data were compared using a two-tailed t-test. Sex distribution and frequency of acetaminophen consumption were measured using χ2 test. P < 0.05 was considered statistically significant. Results: The Oucher pain scale at 4, 6, 12, and 24 h after surgery, the total analgesic consumption and the numbers of demand for supplemental acetaminophen were lower statistically in preincisional group (P < 0.05). Extubation time and duration were higher in preincisional group (P < 0.05). Mean changes of heart rates were statistically lower during the anesthesia period and recovery time in preincisional group (P < 0.05). Conclusion: Preincisional caudal analgesia with a single injection of 0.125% bupivacaine is more effective than the postincisional one for postoperative pain relief and analgesic consumption in unilateral pediatric herniorrhaphy. PMID:21804795

  19. A NUMERICAL METHOD FOR STUDYING SUPER-EDDINGTON MASS TRANSFER IN DOUBLE WHITE DWARF BINARIES

    SciTech Connect

    Marcello, Dominic C.; Tohline, Joel E. E-mail: tohline@phys.lsu.edu

    2012-04-01

    We present a numerical method for the study of double white dwarf (DWD) binary systems at the onset of super-Eddington mass transfer. We incorporate the physics of ideal inviscid hydrodynamical flow, Newtonian self-gravity, and radiation transport on a three-dimensional uniformly rotating cylindrical Eulerian grid. Care has been taken to conserve the key physical quantities such as angular momentum and energy. Our new method conserves total energy to a higher degree of accuracy than other codes that are presently being used to model mass transfer in DWD systems. We present the results of verification tests and simulate the first 20 + orbits of a binary system of mass ratio q 0.7 at the onset of dynamically unstable direct impact mass transfer. The mass transfer rate quickly exceeds the critical Eddington limit by many orders of magnitude, and thus we are unable to model a trans-Eddington phase. It appears that radiation pressure does not significantly affect the accretion flow in the highly super-Eddington regime. An optically thick common envelope forms around the binary within a few orbits. Although this envelope quickly exceeds the spatial domain of the computational grid, the fraction of the common envelope that exceeds zero gravitational binding energy is extremely small, suggesting that radiation-driven mass loss is insignificant in this regime. It remains to be seen whether simulations that capture the trans-Eddington phase of such flows will lead to the same conclusion or show that substantial material gets expelled.

  20. A comparison between subpleural patient-controlled analgesia by bupivacaine and intermittent analgesia in post-operative thoracotomy: A double-blind randomized clinical trial*

    PubMed Central

    Goharian, Vahid; Tabatabaee, Sayyed Abbas; MozafarHashemi, Sayyed; Mohajery, Gholamreza; Ramezani, Mohammad Arash; Shabani, Fatemeh; MotevalliEmami, Zahra

    2011-01-01

    BACKGROUND: The efficacy of subpleural analgesia to reduce postoperative pain intensity in patients after lateral thoracotomy is controversial. In this study, we demonstrated the efficacy of two types of subpleural analgesia. METHODS: This prospective, controlled, randomized, double-blind trial was performed in Department of Thoracic Surgery of Alzahra Hospital associated with Isfahan University of Medical Sciences from June 2009 until August 2010. After posterolateral thoracotomy and admission to the ICU, patients were randomly assigned into two groups of subpleural patient-controlled analgesia (SPCA) (0.02 cc/kg/h of 0.5% bupivacaine) and subpleural intermittent analgesia (SIA) (0.1cc/kg/6h of 0.5% bupivacaine). The data regarding age, sex, visual analog scale (VAS) (at 8, 16 and 24 hours after initiation of analgesia), morphine consumption, systemic adverse effects, length of ICU and hospital stay, complications, public health service (PHS) criteria, and cost was recorded. Data was analyzed by Mann-Whitney U-test, repeated measured test, chi-square test and the Fisher's exact test. A p < 0.05 was considered significant. RESULTS: The study population consisted of 90 patients. There were no significant differences in sex, age, weight, intraoperative analgesics, duration of one-lung ventilation, and adverse effects between the SPCA and SIA groups. Although pain scores were significantly reduced at 16 hours after the first subpleural instillation of bupivacaine 0.5% with patient-controlled analgesia, comparison between mean pain scores in the two groups at 8 and 24 hours after the first subpleural instillation of bupivacaine 0.5% revealed no significant difference. In addition, no significant difference was found in VAS scores at the three evaluated times (p < 0.05). CONCLUSIONS: Optimal use of SPCA bupivacaine for postoperative pain treatment is more effective in pain reduction than SIA bupivacaine. The consumption rate of opioid and bupivacaine was also decreased

  1. Today a Duo, but Once a Trio? The Double White Dwarf HS 2220+2146 May Be a Post-blue Straggler Binary

    NASA Astrophysics Data System (ADS)

    Andrews, Jeff J.; Agüeros, Marcel; Brown, Warren R.; Gosnell, Natalie M.; Gianninas, A.; Kilic, Mukremin; Koester, Detlev

    2016-09-01

    For sufficiently wide orbital separations a, the two members of a stellar binary evolve independently. This implies that in a wide double white dwarf (DWD), the more massive WD should always be produced first, when its more massive progenitor ends its main sequence (MS) life, and should therefore be older and cooler than its companion. The bound, wide DWD HS 2220+2146 (a≈ 500 au) does not conform to this picture: the more massive WD is the younger and hotter of the pair. We show that this discrepancy is unlikely to be due to past mass-transfer phases or to the presence of an unresolved companion. Instead, we propose that HS 2220+2146 formed through a new wide DWD evolutionary channel involving the merger of the inner binary in a hierarchical triple system. The resulting blue straggler and its wide companion then evolved independently, forming the WD pair seen today. Although we cannot rule out other scenarios, the most likely formation channel has the inner binary merging while both stars are still on the MS. This provides us with the tantalizing possibility that Kozai–Lidov oscillations may have played a role in the inner binary’s merger. Gaia may uncover hundreds more wide DWDs, leading to the identification of other systems like HS 2220+2146. There are already indications that other WD systems may have been formed through different, but related, hierarchical triple evolutionary scenarios. Characterizing these populations may allow for thorough testing of the efficiency with which Kozai–Lidov oscillations induce stellar mergers.

  2. The long and the short of it: modelling double neutron star and collapsar Galactic dynamics

    NASA Astrophysics Data System (ADS)

    Kiel, Paul D.; Hurley, Jarrod R.; Bailes, Matthew

    2010-07-01

    Understanding the nature of galactic populations of double compact binaries (where both stars are a neutron star or black hole) has been a topic of interest for many years, particularly the coalescence rate of these binaries. The only observed systems thus far are double neutron star systems containing one or more radio pulsars. However, theorists have postulated that short-duration gamma-ray bursts may be evidence of coalescing double neutron star or neutron star-black hole binaries, while long-duration gamma-ray bursts are possibly formed by tidally enhanced rapidly rotating massive stars that collapse to form black holes (collapsars). The work presented here examines populations of double compact binary systems and tidally enhanced collapsars. We make use of BINPOP and BINKIN, two components of a recently developed population synthesis package. Results focus on correlations of both binary and spatial evolutionary population characteristics. Pulsar and long-duration gamma-ray burst observations are used in concert with our models to draw the conclusions that (i) double neutron star binaries can merge rapidly on time-scales of a few million years (much less than that found for the observed double neutron star population), (ii) common-envelope evolution within these models is a very important phase in double neutron star formation and (iii) observations of long gamma-ray burst projected distances are more centrally concentrated than our simulated coalescing double neutron star and collapsar Galactic populations. Better agreement is found with dwarf galaxy models although the outcome is strongly linked to the assumed birth radial distribution. The birth rate of the double neutron star population in our models ranges from 4 to 160 Myr-1 and the merger rate ranges from 3 to 150 Myr-1. The upper and lower limits of the rates result from including electron-capture supernova kicks to neutron stars and decreasing the common-envelope efficiency, respectively. Our double

  3. Double-helix stellarator

    SciTech Connect

    Moroz, P.E.

    1997-09-01

    A new stellarator configuration, the Double-Helix Stellarator (DHS), is introduced. This novel configuration features a double-helix center post as the only helical element of the stellarator coil system. The DHS configuration has many unique characteristics. One of them is the extreme low plasma aspect ratio, A {approx} 1--1.2. Other advantages include a high enclosed volume, appreciable rotational transform, and a possibility of extreme-high-{beta} MHD equilibria. Moreover, the DHS features improved transport characteristics caused by the absence of the magnetic field ripple on the outboard of the torus. Compactness, simplicity and modularity of the coil system add to the DHS advantages for fusion applications.

  4. Patient Background Factors Affecting the Therapeutic Outcomes in Response to Eszopiclone in Adult Patients with Chronic Insomnia: A Post Hoc Analysis of a Double-Blind Phase III Study in Japan

    PubMed Central

    Inoue, Yuichi; Kamijo, Atsushi; Nagai, Reiko

    2015-01-01

    Study Objective: To identify whether baseline demographic factors or subjective sleep variables are associated with the outcomes following treatment with eszopiclone using data from a recent randomized controlled trial of 78 Japanese subjects with insomnia who were treated with 2 mg eszopiclone per day. Methods: We performed a post hoc analysis of factors including sleep latency (SL), wake time after sleep onset (WASO) (both assessed via sleep diaries), and several demographic variables. Subjects with a SL or WASO > 30 min at baseline and with evaluable SL/WASO data at Week 4 were included in SL and WASO remitter analyses, respectively; those with a SL or WASO ≤ 30 min at Week 4 were defined as SL or WASO remitters, respectively. Threshold baseline SL and WASO values for identification of remitters were determined. Results: No relationships between subjectively assessed therapeutic outcomes and demographic factors were identified. Patients with shorter SL and lower WASO values at baseline showed better outcomes following treatment with eszopiclone in terms of SL and WASO changes, respectively. Baseline SL of 75 min and baseline WASO of 80 min were selected as arbitrary cutoff values for determination of SL and WASO remitters/non-remitters, respectively. Conclusions: These findings may help clinicians to predict their patients' outcomes in response to standard doses of eszopiclone in clinical practice. Citation: Inoue Y, Kamijo A, Nagai R. Patient background factors affecting the therapeutic outcomes in response to eszopiclone in adult patients with chronic insomnia: a post hoc analysis of a double-blind phase III study in Japan. J Clin Sleep Med 2015;11(10):1171–1178. PMID:26094929

  5. Efficacy and acceptability of atypical antipsychotics for the treatment of post-traumatic stress disorder: a meta-analysis of randomized, double-blind, placebo-controlled clinical trials.

    PubMed

    Liu, Xiao-hui; Xie, Xin-hui; Wang, Ke-yong; Cui, Hong

    2014-11-30

    As some evidences demonstrated that atypical antipsychotics (AA) may be efficacious in treating post-traumatic stress disorder (PTSD), we preformed a meta-analysis of randomized, double-blind, placebo-controlled clinical trials (RCTs) of AAs for the treatment of PTSD. Two hundred and fifty one papers were searched and screened. Eight RCTs met the inclusion criteria. AAs may be superior to placebo in the treatment of PTSD, as indicated by the changes in Clinician Administered PTSD Scale (CAPS) total scores (weighted mean differences (WMD)=-5.89, 95% confidence interval (CI) [-9.21, -2.56], P=0.0005) and also in CAPS subscale intrusion (WMD=-2.58, 95% CI[-3.83, -1.33], P<0.0001 ) and subscale hyperarousal (WMD=-2.94, 95% CI[-5.45, -0.43], P=0.02). The acceptability measured by dropout rates between AAs and placebo showed no statistical difference (OR=1.24, 95%CI [0.78, 1.97], P=0.36). PTSD symptom cluster, especially in intrusion and hyperarousal. However, we should be careful to generalize the conclusion because of the small number of included trails. We expect more RCTs will be done in the future so as to clarify the specific value of AAs for PTSD. PMID:25015709

  6. An ALMA view of the post-AGB object HD 101584

    NASA Astrophysics Data System (ADS)

    Olofsson, H.; Vlemmings, W.; Maercker, M.; Humphreys, E.; Lindqvist, M.; Nyman, L.; Ramstedt, S.

    2016-07-01

    ALMA cycles 1 and 3 observations of CO isotopologues and 1.3mm continuum are used in a study of the circumstellar environment of the binary HD 101584, a post-AGB star and a low-mass companion that is most likely a post-common-envelope-evolution system. These data are supplemented with new information from OH maser emission. It is inferred that the large- scale circumstellar medium has a bipolar hour-glass structure, seen almost pole-on, formed by an energetic, ≥⃒ 150 km s-1, jet. Significant amount of material still resides in the central region. It is proposed that the circumstellar morphology is related to an event which took place ≤⃒ 500 yr ago, possibly a capture event where the companion spiralled in towards the AGB star. Several observed features remain to be explained, and may hint to a more complicated scenario.

  7. Repetitive H-Wave® device stimulation and program induces significant increases in the range of motion of post operative rotator cuff reconstruction in a double-blinded randomized placebo controlled human study

    PubMed Central

    Blum, Kenneth; Chen, Amanda LC; Chen, Thomas JH; Waite, Roger L; Downs, B William; Braverman, Eric R; Kerner, Mallory M; Savarimuthu, Stella M; DiNubile, Nicholas

    2009-01-01

    significant increase in range of motion in positive management of rotator cuff reconstruction, supporting other previous research on HWDS and improvement in function. Interpretation of this preliminary investigation while suggestive of significant increases in Range of Motion of Post -Operative Rotator Cuff Reconstruction, warrants further confirmation in a larger double-blinded sham controlled randomized study. PMID:19874593

  8. Angular Momentum Transport in Double White Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Motl, Patrick M.; Tohline, Joel E.; Frank, Juhan

    2006-11-01

    We present simulations of dynamical mass transfer in a double white dwarf binary with an initial mass ratio of 0.4. The binary components are approximated as polytropes of index n = 3/2 and the synchronously rotating, semi-detached equilibrium binary is evolved hydrodynamically with the gravitational potential being computed through the solution of Poisson's equation. Upon initiating deep contact, the mass transfer rate grows by more than an order of magnitude over approximately ten orbits, as would be expected for dynamically unstable mass transfer. However, the mass transfer rate then reaches a peak value, the binary expands and the mass transfer event subsides over approximately 30 orbits. Despite the loss of orbital angular momentum into the spin of the accreting star, we find that the accretor's spin saturates and the binary responds as one would expect for a system with an accretion disk filling a substantial fraction of the accretor's Roche lobe. It appears that double white dwarf binaries may be more resilient against merger than previously anticipated though our simulations do not include radiation forces which may ultimately fill a common envelope which dooms the binary.

  9. What is the ideal dose and power output of low-level laser therapy (810 nm) on muscle performance and post-exercise recovery? Study protocol for a double-blind, randomized, placebo-controlled trial

    PubMed Central

    2014-01-01

    Background Recent studies involving phototherapy applied prior to exercise have demonstrated positive results regarding the attenuation of muscle fatigue and the expression of biochemical markers associated with recovery. However, a number of factors remain unknown, such as the ideal dose and application parameters, mechanisms of action and long-term effects on muscle recovery. The aims of the proposed project are to evaluate the long-term effects of low-level laser therapy on post-exercise musculoskeletal recovery and identify the best dose andapplication power/irradiation time. Design and methods A double-blind, randomized, placebo-controlled clinical trial with be conducted. After fulfilling the eligibility criteria, 28 high-performance athletes will be allocated to four groups of seven volunteers each. In phase 1, the laser power will be 200 mW and different doses will be tested: Group A (2 J), Group B (6 J), Group C (10 J) and Group D (0 J). In phase 2, the best dose obtained in phase 1 will be used with the same distribution of the volunteers, but with different powers: Group A (100 mW), Group B (200 mW), Group C (400 mW) and Group D (0 mW). The isokinetic test will be performed based on maximum voluntary contraction prior to the application of the laser and after the eccentric contraction protocol, which will also be performed using the isokinetic dynamometer. The following variables related to physical performance will be analyzed: peak torque/maximum voluntary contraction, delayed onset muscle soreness (algometer), biochemical markers of muscle damage, inflammation and oxidative stress. Discussion Our intention, is to determine optimal laser therapy application parameters capable of slowing down the physiological muscle fatigue process, reducing injuries or micro-injuries in skeletal muscle stemming from physical exertion and accelerating post-exercise muscle recovery. We believe that, unlike drug therapy, LLLT has a biphasic dose–response pattern. Trial

  10. The efficacy of extended-release levomilnacipran in moderate to severe major depressive disorder: secondary and post-hoc analyses from a randomized, double-blind, placebo-controlled study.

    PubMed

    Montgomery, Stuart A; Mansuy, Lucilla; Ruth, Adam C; Li, Dayong; Gommoll, Carl

    2014-01-01

    Levomilnacipran (1S, 2R-milnacipran) is a potent and selective serotonin and norepinephrine reuptake inhibitor that is Food and Drug Administration approved for once-daily treatment of major depressive disorder in adults. Secondary and post-hoc analyses were carried out on data from a positive 10-week, randomized, double-blind, placebo-controlled, parallel-group, multicenter, proof-of-concept trial (EudraCT Number: 2006-002404-34) on 75 or 100 mg/day levomilnacipran extended release (ER). Included outpatients (18-70 years) met the criteria for a major depressive episode. There was a statistically significant difference in favor of levomilnacipran ER versus placebo in change from baseline to week 10 on every Montgomery Åsberg Depression Rating Scale (MADRS) single item (mixed-effects model for repeated measures; P<0.05) and most Hamilton Depression Rating Scale (HAMD17) single items. Significantly more levomilnacipran ER versus placebo patients (P < 0.05) achieved 'complete' (MADRS ≤ 5; 24 vs. 10%) and 'sustained' (MADRS ≤ 10 in Weeks 4-10; 16 vs. 10%) remission, Sheehan Disability Scale (SDS) response (total score ≤ 12 and each item score ≤ 4; 52 vs. 35%) and remission (total score ≤ 6 and each item score ≤ 2; 26 vs. 17%), and combined symptomatic (MADRS) and functional (SDS) remission (19 vs. 8%). Treatment effects of similar magnitude were observed in the severe depression subgroup (MADRS ≥ 30). These results demonstrate the benefit of levomilnacipran ER over placebo for patients with symptomatic and functional impairment associated with major depressive disorder. PMID:24172160

  11. THE POST-MERGER MAGNETIZED EVOLUTION OF WHITE DWARF BINARIES: THE DOUBLE-DEGENERATE CHANNEL OF SUB-CHANDRASEKHAR TYPE Ia SUPERNOVAE AND THE FORMATION OF MAGNETIZED WHITE DWARFS

    SciTech Connect

    Ji Suoqing; Fisher, Robert T.; Garcia-Berro, Enrique; Loren-Aguilar, Pablo; Cremer, Pascal; Behrends, Jan

    2013-08-20

    Type Ia supernovae (SNe Ia) play a crucial role as standardizable cosmological candles, though the nature of their progenitors is a subject of active investigation. Recent observational and theoretical work has pointed to merging white dwarf binaries, referred to as the double-degenerate channel, as the possible progenitor systems for some SNe Ia. Additionally, recent theoretical work suggests that mergers which fail to detonate may produce magnetized, rapidly rotating white dwarfs. In this paper, we present the first multidimensional simulations of the post-merger evolution of white dwarf binaries to include the effect of the magnetic field. In these systems, the two white dwarfs complete a final merger on a dynamical timescale, and are tidally disrupted, producing a rapidly rotating white dwarf merger surrounded by a hot corona and a thick, differentially rotating disk. The disk is strongly susceptible to the magnetorotational instability (MRI), and we demonstrate that this leads to the rapid growth of an initially dynamically weak magnetic field in the disk, the spin-down of the white dwarf merger, and to the subsequent central ignition of the white dwarf merger. Additionally, these magnetized models exhibit new features not present in prior hydrodynamic studies of white dwarf mergers, including the development of MRI turbulence in the hot disk, magnetized outflows carrying a significant fraction of the disk mass, and the magnetization of the white dwarf merger to field strengths {approx}2 Multiplication-Sign 10{sup 8} G. We discuss the impact of our findings on the origins, circumstellar media, and observed properties of SNe Ia and magnetized white dwarfs.

  12. Randomized, double-blind, active-controlled study evaluating the safety and immunogenicity of three vaccination schedules and two dose levels of AV7909 vaccine for anthrax post-exposure prophylaxis in healthy adults.

    PubMed

    Hopkins, Robert J; Kalsi, Gurdyal; Montalvo-Lugo, Victor M; Sharma, Mona; Wu, Yukun; Muse, Derek D; Sheldon, Eric A; Hampel, Frank C; Lemiale, Laurence

    2016-04-19

    AV7909 vaccine being developed for post-exposure prophylaxis of anthrax disease may require fewer vaccinations and reduced amount of antigen to achieve an accelerated immune response over BioThrax(®) (Anthrax Vaccine Adsorbed). A phase 2, randomized, double-blind, BioThrax vacccine-controlled study was conducted to evaluate the safety and immunogenicity of three intramuscular vaccination schedules and two dose levels of AV7909 in 168 healthy adults. Subjects were randomized at a 4:3:2:4:2 ratio to 5 groups: (1) AV7909 on Days 0/14; (2) AV7909 on Days 0/28; (3) AV7909 on Days 0/14/28; (4) half dose AV7909 on Days 0/14/28; and (5) BioThrax vaccine on Days 0/14/28. Vaccinations in all groups were well tolerated. The incidences of adverse events (AEs) were 79% for AV7909 subjects and 65% for BioThrax subjects; 92% of AV7909 subjects and 87% of BioThrax subjects having AEs reported Grade 1-2 AEs. No serious AEs were assessed as potentially vaccine-related, and no AEs of potential autoimmune etiology were reported. There was no discernible pattern indicative of a safety concern across groups in the incidence or severity of reactogenicity events. Groups 2-4 achieved success for the primary endpoint, demonstrated by a lower 95% confidence limit of the percentage of subjects with protective toxin neutralizing antibody NF50 values (≥0.56) to be ≥40% at Day 63. Group 1 marginally missed the criterion (lower bound 95% confidence limit of 39.5%). Immune responses were above this threshold for Groups 1, 3 and 4 at Day 28 and all groups at Day 42. Further study of an AV7909 two-dose schedule given 2 weeks apart is warranted in light of the favorable tolerability profile and immunogenicity response relative to three doses of BioThrax vaccine, as well as preliminary data from nonclinical studies indicating similar immune responses correlate with higher survival for AV7909 than BioThrax vaccine. PMID:26979136

  13. The gravitational-wave signal generated by a galactic population of double neutron-star binaries

    NASA Astrophysics Data System (ADS)

    Yu, Shenghua; Jeffery, C. Simon

    2015-04-01

    We investigate the gravitational wave (GW) signal generated by a population of double neutron-star (DNS) binaries with eccentric orbits caused by kicks during supernova collapse and binary evolution. The DNS population of a standard Milky Way-type galaxy has been studied as a function of star formation history, initial mass function (IMF) and metallicity and of the binary-star common-envelope ejection process. The model provides birthrates, merger rates and total number of DNS as a function of time. The GW signal produced by this population has been computed and expressed in terms of a hypothetical space GW detector (eLISA) by calculating the number of discrete GW signals at different confidence levels, where `signal' refers to detectable GW strain in a given frequency-resolution element. In terms of the parameter space explored, the number of DNS-originating GW signals is greatest in regions of recent star formation, and is significantly increased if metallicity is reduced from 0.02 to 0.001, consistent with Belczynski et al. Increasing the IMF power-law index (from -2.5 to -1.5) increases the number of GW signals by a large factor. This number is also much higher for models where the common-envelope ejection is treated using the α-mechanism (energy conservation) than when using the γ-mechanism (angular-momentum conservation). We have estimated the total number of detectable DNS GW signals from the Galaxy by combining contributions from thin disc, thick disc, bulge and halo. The most probable numbers for an eLISA-type experiment are 0-1600 signals per year at S/N ≥ 1, 0-900 signals per year at S/N ≥ 3, and 0-570 at S/N ≥ 5, coming from about 0-65, 0-60 and 0-50 resolved DNS, respectively.

  14. Most Double Degenerate Low-mass White Dwarf Binaries Merge

    NASA Astrophysics Data System (ADS)

    Brown, Warren R.; Kilic, Mukremin; Kenyon, Scott J.; Gianninas, A.

    2016-06-01

    We estimate the merger rate of double degenerate binaries containing extremely low mass (ELM; \\lt 0.3 M ⊙) white dwarfs (WDs) in the Galaxy. Such WDs are detectable for timescales of 0.1–1 Gyr in the ELM Survey; the binaries they reside in have gravitational wave merger times of 0.001–100 Gyr. To explain the observed distribution requires that most ELM WD binary progenitors detach from the common envelope phase with <1 hr orbital periods. We calculate the local space density of ELM WD binaries and estimate a merger rate of 3 × 10‑3 yr‑1 over the entire disk of the Milky Way; the merger rate in the halo is 10 times smaller. The ELM WD binary merger rate exceeds by a factor of 40 the formation rate of stable mass transfer AM CVn binaries, marginally exceeds the rate of underluminous supernovae, and is identical to the formation rate of R CrB stars. On this basis, we conclude that ELM WD binaries can be the progenitors of all observed AM CVn and possibly underluminous supernovae; however, the majority of He+CO WD binaries go through unstable mass transfer and merge, e.g., into single massive ∼1 M ⊙ WDs.

  15. DOUBLE COMPACT OBJECTS AS LOW-FREQUENCY GRAVITATIONAL WAVE SOURCES

    SciTech Connect

    Belczynski, Krzysztof; Bulik, Tomasz; Benacquista, Matthew

    2010-12-10

    We study the Galactic field population of double compact objects (DCOs; NS-NS, BH-NS, BH-BH binaries) to investigate the number (if any) of these systems that can potentially be detected with the Laser Interferometer Space Antenna (LISA) at low gravitational wave frequencies. We calculate the Galactic numbers and physical properties of these binaries and show their relative contributions from the disk, bulge, and halo. Although the Galaxy hosts {approx}10{sup 5} DCO binaries emitting low-frequency gravitational waves, only a handful of these objects in the disk will be detectable with LISA, but none from the halo or bulge. This is because the bulk of these binaries are NS-NS systems with high eccentricities and long orbital periods (weeks/months) causing inefficient signal accumulation (a small number of signal bursts at periastron passage in one year of LISA observations) and rendering them undetectable in the majority of these cases. We adopt two evolutionary models that differ in their treatment of the common envelope (CE) phase that is a major (and still mostly unknown) process in the formation of close DCOs. Depending on the evolutionary model adopted, our calculations indicate the likely detection of about four NS-NS binaries and two BH-BH systems (model A; likely survival of progenitors through CE) or only a couple of NS-NS binaries (model B; suppression of the DCO formation due to CE mergers).

  16. Merging binary stars and the magnetic white dwarfs

    NASA Astrophysics Data System (ADS)

    Briggs, Gordon P.; Ferrario, Lilia; Tout, Christopher A.; Wickramasinghe, Dayal T.; Hurley, Jarrod R.

    2015-02-01

    A magnetic dynamo driven by differential rotation generated when stars merge can explain strong fields in certain classes of magnetic stars, including the high field magnetic white dwarfs (HFMWDs). In their case the site of the differential rotation has been variously proposed to be within a common envelope, the massive hot outer regions of a merged degenerate core or an accretion disc formed by a tidally disrupted companion that is subsequently incorporated into a degenerate core. We synthesize a population of binary systems to investigate the stellar merging hypothesis for observed single HFMWDs. Our calculations provide mass distribution and the fractions of white dwarfs that merge during a common envelope phase or as double degenerate systems in a post-common-envelope phase. We vary the common envelope efficiency parameter α and compare with observations. We find that this hypothesis can explain both the observed incidence of magnetism and the mass distribution of HFMWDs for a wide range of α. In this model, the majority of the HFMWDs are of the carbon-oxygen type and merge within a common envelope. Less than about a quarter of a per cent of HFMWDs originate from double degenerate stars that merge after common envelope evolution and these populate the high-mass tail of the HFMWD mass distribution.

  17. Double Layers in Astrophysics

    NASA Technical Reports Server (NTRS)

    Williams, Alton C. (Editor); Moorehead, Tauna W. (Editor)

    1987-01-01

    Topics addressed include: laboratory double layers; ion-acoustic double layers; pumping potential wells; ion phase-space vortices; weak double layers; electric fields and double layers in plasmas; auroral double layers; double layer formation in a plasma; beamed emission from gamma-ray burst source; double layers and extragalactic jets; and electric potential between plasma sheet clouds.

  18. Post clamp

    NASA Technical Reports Server (NTRS)

    Ramsey, John K. (Inventor); Meyn, Erwin H. (Inventor)

    1990-01-01

    A pair of spaced collars are mounted at right angles on a clamp body by retaining rings which enable the collars to rotate with respect to the clamp body. Mounting posts extend through aligned holes in the collars and clamp body. Each collar can be clamped onto the inserted post while the clamp body remains free to rotate about the post and collar. The clamp body is selectively clamped onto each post.

  19. Double screening

    NASA Astrophysics Data System (ADS)

    Gratia, Pierre; Hu, Wayne; Joyce, Austin; Ribeiro, Raquel H.

    2016-06-01

    Attempts to modify gravity in the infrared typically require a screening mechanism to ensure consistency with local tests of gravity. These screening mechanisms fit into three broad classes; we investigate theories which are capable of exhibiting more than one type of screening. Specifically, we focus on a simple model which exhibits both Vainshtein and kinetic screening. We point out that due to the two characteristic length scales in the problem, the type of screening that dominates depends on the mass of the sourcing object, allowing for different phenomenology at different scales. We consider embedding this double screening phenomenology in a broader cosmological scenario and show that the simplest examples that exhibit double screening are radiatively stable.

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

    PubMed

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

    2015-03-01

    The planetary nebula stage is the ultimate fate of stars with masses one to eight times that of the Sun (M(⊙)). The origin of their complex morphologies is poorly understood, although several mechanisms involving binary interaction have been proposed. In close binary systems, the orbital separation is short enough for the primary star to overfill its Roche lobe as the star expands during the asymptotic giant branch phase. The excess gas eventually forms a common envelope surrounding both stars. Drag forces then result in the envelope being ejected into a bipolar planetary nebula whose equator is coincident with the orbital plane of the system. Systems in which both stars have ejected their envelopes and are evolving towards the white dwarf stage are said to be double degenerate. Here we report that Henize 2-428 has a double-degenerate core with a combined mass of ∼1.76M(⊙), which is above the Chandrasekhar limit (the maximum mass of a stable white dwarf) of 1.4M(⊙). This, together with its short orbital period (4.2 hours), suggests that the system should merge in 700 million years, triggering a type Ia supernova event. This supports the hypothesis of the double-degenerate, super-Chandrasekhar evolutionary pathway for the formation of type Ia supernovae. PMID:25686608

  1. Double White Dwarf Merger Rates

    NASA Astrophysics Data System (ADS)

    Toonen, Silvia; Nelemans, Gijs; Portegies Zwart, Simon

    2013-01-01

    Type Ia supernovae (SNe Ia) are very successfully used as standard candles on cosmological distance scales, but so far the nature of the progenitor(s) is unclear. A possible scenario for SNe Ia are merging carbon/oxygen white dwarfs with a combined mass exceeding the Chandrasekhar mass. We determine the theoretical rates and delay time distribution of these mergers for two different common envelope prescriptions and metallicities. The shape of the delay time distributions is rather insensitive to the assumptions. The normalization is a factor ~3-13 too low compared to observations.

  2. Double field theory inspired cosmology

    SciTech Connect

    Wu, Houwen; Yang, Haitang E-mail: hyanga@scu.edu.cn

    2014-07-01

    Double field theory proposes a generalized spacetime action possessing manifest T-duality on the level of component fields. We calculate the cosmological solutions of double field theory with vanishing Kalb-Ramond field. It turns out that double field theory provides a more consistent way to construct cosmological solutions than the standard string cosmology. We construct solutions for vanishing and non-vanishing symmetry preserving dilaton potentials. The solutions assemble the pre- and post-big bang evolutions in one single line element. Our results show a smooth evolution from an anisotropic early stage to an isotropic phase without any special initial conditions in contrast to previous models. In addition, we demonstrate that the contraction of the dual space automatically leads to both an inflation phase and a decelerated expansion of the ordinary space during different evolution stages.

  3. The yellow hypergiant HR 5171 A: Resolving a massive interacting binary in the common envelope phase

    NASA Astrophysics Data System (ADS)

    Chesneau, O.; Meilland, A.; Chapellier, E.; Millour, F.; van Genderen, A. M.; Nazé, Y.; Smith, N.; Spang, A.; Smoker, J. V.; Dessart, L.; Kanaan, S.; Bendjoya, Ph.; Feast, M. W.; Groh, J. H.; Lobel, A.; Nardetto, N.; Otero, S.; Oudmaijer, R. D.; Tekola, A. G.; Whitelock, P. A.; Arcos, C.; Curé, M.; Vanzi, L.

    2014-03-01

    Context. Only a few stars are caught in the very brief and often crucial stages when they quickly traverse the Hertzsprung-Russell diagram, and none has yet been spatially resolved in the mass transfer phase. Aims: We initiated long-term optical interferometry monitoring of the diameters of massive and unstable yellow hypergiants (YHG) with the goal of detecting both the long-term evolution of their radius and shorter term formation of a possible pseudo-photosphere related to proposed large mass-loss events. Methods: We observed HR 5171 A with AMBER/VLTI. We also examined archival photometric data in the visual and near-IR spanning more than 60 years, as well as sparse spectroscopic data. Results: HR 5171 A exhibits a complex appearance. Our AMBER data reveal a surprisingly large star for a YHG R∗ = 1315 ± 260R⊙ (or ~6.1 AU) at the distance of 3.6 ± 0.5 kpc. The source is surrounded by an extended nebulosity, and these data also show a large level of asymmetry in the brightness distribution of the system, which we attribute to a newly discovered companion star located in front of the primary star. The companion's signature is also detected in the visual photometry, which indicates an orbital period of Porb = 1304 ± 6 d. Modeling the light curve with the NIGHTFALL program provides clear evidence that the system is a contact or possibly over-contact eclipsing binary. A total current system mass of 39+40-22 M⊙ and a high mass ratio q ≥ 10 is inferred for the system. Conclusions: The low-mass companion of HR 5171 A is very close to the primary star that is embedded within its dense wind. Tight constraints on the inclination and vsini of the primary are lacking, which prevents us from determining its influence precisely on the mass-loss phenomenon, but the system is probably experiencing a wind Roche-Lobe overflow. Depending on the amount of angular momentum that can be transferred to the stellar envelope, HR 5171 A may become a fast-rotating B[e]/luminous blue variable/Wolf-Rayet star. In any case, HR 5171 A highlights the possible importance of binaries for interpreting the unstable YHGs and for massive star evolution in general. Based on observations made with ESO telescopes at the La Silla/ Paranal Observatory under program ID 088.D-0129 and from Gemini/South Observatory under program GS-2011A-C-4.Appendices are available in electronic form at http://www.aanda.org

  4. DISCOVERY OF A BRIGHT, EXTREMELY LOW MASS WHITE DWARF IN A CLOSE DOUBLE DEGENERATE SYSTEM

    SciTech Connect

    Vennes, S.; Kawka, A.; Nemeth, P.; Thorstensen, J. R.; Skinner, J. N.; Pigulski, A.; Steslicki, M.; Kolaczkowski, Z.; Srodka, P.

    2011-08-10

    We report the discovery of a bright (V {approx} 13.7), extremely low mass white dwarf in a close double degenerate system. We originally selected GALEX J171708.5+675712 for spectroscopic follow-up among a group of white dwarf candidates in an ultraviolet-optical reduced proper-motion diagram. The new white dwarf has a mass of 0.18 M{sub sun} and is the primary component of a close double degenerate system (P = 0.246137 days, K{sub 1} = 288 km s{sup -1}) comprising a fainter white dwarf secondary with M{sub 2} {approx} 0.9 M{sub sun}. Light curves phased with the orbital ephemeris show evidence of relativistic beaming and weaker ellipsoidal variations. The light curves also reveal secondary eclipses (depth {approx}8 mmag) while the primary eclipses appear partially compensated by the secondary gravitational deflection and are below detection limits. Photospheric abundance measurements show a nearly solar composition of Si, Ca, and Fe (0.1-1 sun), while the normal kinematics suggest a relatively recent formation history. Close binary evolutionary scenarios suggest that extremely low mass white dwarfs form via a common-envelope phase and possible Roche lobe overflow.

  5. Double pituitary adenomas.

    PubMed

    Iacovazzo, D; Bianchi, A; Lugli, F; Milardi, D; Giampietro, A; Lucci-Cordisco, E; Doglietto, F; Lauriola, L; De Marinis, L

    2013-04-01

    Double pituitary adenomas represent up to 2.6 % of pituitary adenomas in large surgical series and up to 3.3 % of patients with Cushing's disease have been found to have double or multiple pituitary adenomas. We report the case of a 60-year-old male patient whose medical history began in 2002 with erectile dysfunction; hyperprolactinemia was found and MRI showed a 6-mm area of delayed enhancement in the lateral portion of the right pituitary lobe. Treatment with cabergoline was started with normalization of prolactin levels; the following MRI, performed in 2005 and 2008, showed shrinkage of the pituitary lesion. In 2005, the patient began to manifest weight gain, hypertension, and facial plethora, but no further evaluations were done. In January 2010, the patient came to our attention and underwent multiple tests that suggested Cushing's disease. A new MRI was negative. Bilateral inferior petrosal sinus sampling showed significant pituitary-to-peripheral ratio and, in May 2010, the patient underwent exploratory pituitary surgery with evidence of a 1-2-mm white-coloured midline area compatible with pituitary adenoma that was surgically removed. Post-operatively, the patient's clinical conditions improved with onset of secondary hypoadrenalism. The histologic examination confirmed a pituitary adenoma (immunostaining was found to be positive for ACTH and negative for prolactin). We report the case of an ACTH-producing microadenoma metachronous to a prolactin secreting microadenoma although not confirmed histologically, shrunk by medical treatment. A review of data in the literature regarding double or multiple pituitary adenomas has also been done. PMID:23325364

  6. Rehabilitation of endodontically treated teeth using the radiopaque fiber post.

    PubMed

    Brown, Philip L; Hicks, Norman L

    2003-04-01

    Metallic posts fall short of satisfying contemporary guidelines for ideal post/core rehabilitation. Along with technological improvements in adhesive resins, cements, and composite restoratives, the evolution of fiber-reinforced posts allows the rehabilitation of endodontically treated teeth with greater esthetics and virtually no predisposition to root fracture. At least one fiber post system now complies with all of the ideal post characteristics described in the endodontic text. This article describes the potential for displacement of metal posts by low-modulus fiber posts, the differences between them, and the development and placement of a radiopaque, translucent, double-tapered fiber post. PMID:12769029

  7. Seeing Double

    NASA Astrophysics Data System (ADS)

    Pesic, Peter

    2003-10-01

    The separateness and connection of individuals is perhaps the central question of human life: What, exactly, is my individuality? To what degree is it unique? To what degree can it be shared, and how? To the many philosophical and literary speculations about these topics over time, modern science has added the curious twist of quantum theory, which requires that the elementary particles of which everything consists have no individuality at all. All aspects of chemistry depend on this lack of individuality, as do many branches of physics. From where, then, does our individuality come? In Seeing Double, Peter Pesic invites readers to explore this intriguing set of questions. He draws on literary and historical examples that open the mind (from Homer to Martin Guerre to Kafka), philosophical analyses that have helped to make our thinking and speech more precise, and scientific work that has enabled us to characterize the phenomena of nature. Though he does not try to be all-inclusive, Pesic presents a broad range of ideas, building toward a specific point of view: that the crux of modern quantum theory is its clash with our ordinary concept of individuality. This represents a departure from the usual understanding of quantum theory. Pesic argues that what is bizarre about quantum theory becomes more intelligible as we reconsider what we mean by individuality and identity in ordinary experience. In turn, quantum identity opens a new perspective on us. Peter Pesic is a Tutor and Musician-in-Residence at St. John's College, Santa Fe, New Mexico. He has a Ph.D. in physics from Stanford University.

  8. Double inflation

    SciTech Connect

    Silk, J.; Turner, M.S.

    1986-04-01

    The Zel'dovich spectrum of adiabatic density perturbations is a generic prediction of inflation. There is increasing evidence that when the spectrum is normalized by observational data on small scales, there is not enough power on large scales to account for the observed large-scale structure in the Universe. Decoupling the spectrum on large and small scales could solve this problem. As a means of decoupling the large and small scales we propose double inflation (i.e., two episodes of inflation). In this scenario the spectrum on large scales is determined by the first episode of inflation and those on small scales by a second episode of inflation. We present three models for such a scenario. By nearly saturating the large angular-scale cosmic microwave anisotropy bound, we can easily account for the observed large-scale structure. We take the perturbations on small scales to be very large, deltarho/rho approx. = 0.1 to 0.01, which results in the production of primordial black holes (PBHs), early formation of structure, reionization of the Universe, and a rich array of astrophysical events. The ..cap omega..-problem is also addressed by our scenario. Allowing the density perturbations produced by the second episode of inflation to be large also lessens the fine-tuning required in the scalar potential and makes reheating much easier. We briefly speculate on the possibility that the second episode of inflation proceeds through the nucleation of bubbles, which today manifest themselves as empty bubbles whose surfaces are covered with galaxies. 37 refs., 1 fig.

  9. The effects of pre- and post-exercise consumption of multi-ingredient performance supplements on cardiovascular health and body fat in trained men after six weeks of resistance training: a stratified, randomized, double-blind study

    PubMed Central

    2013-01-01

    Background The cardiovascular (CV) and metabolic health benefits or risks associated with consumption of multi-ingredient performance supplements (MIPS) in conjunction with periodized resistance training (RT) in resistance-trained men are unknown. This population is a major target audience for performance supplements, and therefore, the purpose of this study was to investigate the combined effect of RT and commercially available pre- and post-exercise performance supplements on CV health and body fat in resistance-trained men. Methods Twenty-four resistance-trained men completed six weeks (three times/week) of periodized RT while either ingesting SHOT 15-min pre-exercise and SYN immediately post-exercise (multi-ingredient performance supplement group: MIPS) or an isocaloric maltodextrin placebo 15-min pre-exercise and immediately post-exercise (Placebo group). Before and after six weeks of RT and supplementation, resting heart rate (HR), blood pressure (BP), total body fat, android fat, gynoid fat, fat-free mass (FFM) and fasting blood measures of glucose, lipids, nitrate/nitrite (NOx), cortisol and high sensitivity C-reactive protein (hs-CRP) were measured. Statistical analysis was conducted using a one-way ANOVA for baseline differences and a 2 × 2 (group × time) repeated measures ANOVA and Tukey post-hoc tests where appropriate. Significance was set at p < 0.05. Results There was no group × time interaction for HR, BP, blood glucose, lipids, NOx, hs-CRP, cortisol concentrations or body fat. However, there was a time effect where significant decreases in body fat (mean ± SD; MIPS: -1.2 ± 1.2%; Placebo: -0.9 ± 1.1%), android fat (MIPS: -1.8 ± 2.1%; Placebo: -1.6 ± 2.0%), and gynoid fat (MIPS: -1.3 ± 1.6%; Placebo: -1.0 ± 1.4%) for both groups were observed. FFM increased in both groups, and a group × time interaction was observed with MIPS increasing significantly more than the Placebo group (4.2% vs. 1

  10. Double core evolution and X-ray binaries

    NASA Technical Reports Server (NTRS)

    Taam, R. E.

    1979-01-01

    The evolution of a 16-solar mass star and a 1-solar mass neutron star is followed through the common-envelope binary phase. It is found that the encounter of the neutron star with a yellow giant leads to coalescence of the two cores, while encounter with a red giant leads to hydrodynamic expansion and probable ejection of the common envelope. Within the context of the two rotation laws (1) uniform rotation (investigated in the present study), and (2) uniform specific angular momentum (considered in an earlier study), the results are independent of the choice for the angular-momentum distribution in the common envelope. Implications of the results for the binary pulsar phase are discussed.

  11. Crystal chemistry of a Ba-dominant analogue of hydrodelhayelite and natural ion-exchange transformations in double- and triple-layer phyllosilicates in post-volcanic systems of the Eifel region, Germany

    NASA Astrophysics Data System (ADS)

    Zubkova, N. V.; Chukanov, N. V.; Pekov, I. V.; Turchkova, A. G.; Lykova, I. S.; Schüller, W.; Ternes, B.; Pushcharovsky, D. Yu.

    2016-03-01

    A Ba-dominant (Ba > K) analogue of hydrodelhayelite (BDAH) from Löhley (Eifel Mts., Rhineland-Palatinate, Germany) and Ba-enriched varieties of related double- and triple-layer phyllosilicates from Eifel are studied. The crystal structure of BDAH was solved by direct methods and refined to R = 0.0698 [1483 unique reflections with I > 2σ(I)]. It is orthorhombic, Pmmn, a = 23.9532(9), b = 7.0522(3), c = 6.6064(3) Å, V = 1115.97(8) Å3, Z = 2. The structure is based upon delhayelite-type double-layer tetrahedral blocks [(Al,Si)4Si12O34(OH,O)4] connected by chains of (Ca,Fe)-centered octahedra. Ba2+ and subordinate K+ occur at partially vacant sites in zeolitic channels within the tetrahedral blocks. The crystal-chemical formula of BDAH is: (Ba0.42K0.34□0.24)(Ca0.88Fe0.12)2(□0.90Mg0.10)2[Si6(Al0.5Si0.5)2O17(OH0.71O0.29)2]ṡ6H2O. The formation of BDAH and Ba-rich varieties of altered delhayelite/fivegite, günterblassite and hillesheimite is considered as a result of leaching of Na, Cl, F and, partially, K and Ca accompanied with hydration and the capture of Ba as a result of natural ion exchange. These minerals are structurally a "bridge" between single-layer phyllosilicates and zeolites having the open three-dimensional tetrahedral Al-Si-O frameworks.

  12. Quark-novae Occurring in Massive Binaries : A Universal Energy Source in Superluminous Supernovae with Double-peaked Light Curves

    NASA Astrophysics Data System (ADS)

    Ouyed, Rachid; Leahy, Denis; Koning, Nico

    2016-02-01

    A quark-nova (QN; the sudden transition from a neutron star into a quark star), which occurs in the second common envelope (CE) phase of a massive binary, gives excellent fits to superluminous, hydrogen-poor, supernovae (SLSNe) with double-peaked light curves, including DES13S2cmm, SN 2006oz, and LSQ14bdq (http://www.quarknova.ca/LCGallery.html). In our model, the H envelope of the less massive companion is ejected during the first CE phase, while the QN occurs deep inside the second, He-rich, CE phase after the CE has expanded in size to a radius of a few tens to a few thousands of solar radii; this yields the first peak in our model. The ensuing merging of the quark star with the CO core leads to black hole formation and accretion, explaining the second long-lasting peak. We study a sample of eight SLSNe Ic with double-humped light curves. Our model provides good fits to all of these, with a universal explosive energy of 2 × 1052 erg (which is the kinetic energy of the QN ejecta) for the first hump. The late-time emissions seen in iPTF13ehe and LSQ14bdq are fit with a shock interaction between the outgoing He-rich (i.e., second) CE and the previously ejected H-rich (i.e., first) CE.

  13. A double-double/double-single computation package

    SciTech Connect

    Bailey, David H.

    2004-12-01

    The DDFUNIDSFUN software permits a new or existing Fortran-90 program to utilize double-double precision (approx. 31 digits) or double-single precision (approx. 14 digits) arithmetic. Double-double precision is required by a rapidly expandirtg body of scientific computations in physics and mathematics, for which the conventional 64-bit IEEE computer arithmetic (about 16 decimal digit accuracy) is not sufficient. Double-single precision permits users of systems that do not have hardware 64-bit IEEE arithmetic (such as some game systems) to perform arithmetic at a precision nearly as high as that of systems that do. Both packages run significantly faster Than using multiple precision or arbitrary precision software for this purpose. The package includes an extensive set of low-level routines to perform high-precision arithmetic, including routines to calculate various algebraic and transcendental functions, such as square roots, sin, ccc, exp, log and others. In addition, the package includes high-level translation facilities, so that Fortran programs can utilize these facilities by making only a few changes to conventional Fortran programs. In most cases, the only changes that are required are to change the type statements of variables that one wishes to be treated as multiple precision, plus a few other minor changes. The DDFUN package is similar in functionality to the double-double part of the GD package, which was previously written at LBNL. However, the DDFUN package is written exclusively in Fortran-90, thus avoidIng difficulties that some users experience when using GD, which includes both Fortran-90 and C++ code.

  14. A double-double/double-single computation package

    Energy Science and Technology Software Center (ESTSC)

    2004-12-01

    The DDFUNIDSFUN software permits a new or existing Fortran-90 program to utilize double-double precision (approx. 31 digits) or double-single precision (approx. 14 digits) arithmetic. Double-double precision is required by a rapidly expandirtg body of scientific computations in physics and mathematics, for which the conventional 64-bit IEEE computer arithmetic (about 16 decimal digit accuracy) is not sufficient. Double-single precision permits users of systems that do not have hardware 64-bit IEEE arithmetic (such as some game systems)more » to perform arithmetic at a precision nearly as high as that of systems that do. Both packages run significantly faster Than using multiple precision or arbitrary precision software for this purpose. The package includes an extensive set of low-level routines to perform high-precision arithmetic, including routines to calculate various algebraic and transcendental functions, such as square roots, sin, ccc, exp, log and others. In addition, the package includes high-level translation facilities, so that Fortran programs can utilize these facilities by making only a few changes to conventional Fortran programs. In most cases, the only changes that are required are to change the type statements of variables that one wishes to be treated as multiple precision, plus a few other minor changes. The DDFUN package is similar in functionality to the double-double part of the GD package, which was previously written at LBNL. However, the DDFUN package is written exclusively in Fortran-90, thus avoidIng difficulties that some users experience when using GD, which includes both Fortran-90 and C++ code.« less

  15. The Cambridge Double Star Atlas

    NASA Astrophysics Data System (ADS)

    MacEvoy, Bruce; Tirion, Wil

    2015-12-01

    Preface; What are double stars?; The binary orbit; Double star dynamics; Stellar mass and the binary life cycle; The double star population; Detecting double stars; Double star catalogs; Telescope optics; Preparing to observe; Helpful accessories; Viewing challenges; Next steps; Appendices: target list; Useful formulas; Double star orbits; Double star catalogs; The Greek alphabet.

  16. Biological post

    PubMed Central

    Kumar, B. Suresh; Kumar, Senthil; Mohan Kumar, N. S.; Karunakaran, J. V.

    2015-01-01

    Anterior tooth fracture as a result of traumatic injuries, is frequently encountered in endodontic practice. Proper reconstruction of extensively damaged teeth can be achieved through the fragment reattachment procedure known as “biological restoration.” This case report refers to the esthetics and functional recovery of extensively damaged maxillary central incisor through the preparation and adhesive cementation of “biological post” in a young patient. Biological post obtained through extracted teeth from another individual–represent a low-cost option and alternative technique for the morphofunctional recovery of extensively damaged anterior teeth. PMID:26538952

  17. Double outlet right ventricle

    MedlinePlus

    ... medlineplus.gov/ency/article/007328.htm Double outlet right ventricle To use the sharing features on this page, please enable JavaScript. Double outlet right ventricle (DORV) is a heart disease that is ...

  18. Study protocol for a pilot, randomised, double-blinded, placebo controlled trial of perineural local anaesthetics and steroids for chronic post-traumatic neuropathic pain in the ankle and foot: the PREPLANS study

    PubMed Central

    Bhatia, Anuj; Bril, Vera; Brull, Richard T; Perruccio, Anthony; Wijeysundera, Duminda; Alvi, Sabbeh; Lau, Johnny; Gandhi, Rajiv; Mahomed, Nizar; Davis, Aileen M

    2016-01-01

    Introduction Peripheral neuropathic pain (PNP) associated with trauma is often refractory to treatment. Administration of local anaesthetics (LA) and steroids around injured nerves has been proposed as an option for patients unresponsive to conventional treatments for refractory PNP following trauma. There is insufficient evidence to support a large, potentially expensive, full-scale randomised controlled trial (RCT) that involves comparison of effects of perineural steroids and LA against LA or saline injections on analgesia, physical and psychological functioning, and quality of life. There is also a lack of data that would allow estimation of analgesic efficacy or sample size for the full-scale RCT. The objective of this pilot RCT is to yield information to support planning of a full-scale RCT in this population. Methods and Analysis 30 participants with post-traumatic PNP in the ankle and foot of moderate-to-severe intensity and duration of more than 3 months will be enrolled in this pilot RCT. Participants will be randomised to receive three ultrasound-guided perineural injections of 0.9% saline, 0.25% bupivacaine (a long-acting LA) or a combination of 0.25% bupivacaine and a steroid (methylprednisolone 16 mg per nerve) at weekly intervals. The primary objectives are to determine the feasibility and sample size of a full-scale RCT in this population. The secondary objectives are to evaluate the effect of study interventions on analgesia, persistence of neuropathic pain, psychological and physical function, quality of life and participants' global impression of change at 1 and 3 months after the interventions. In addition, adverse effects associated with perineural injections and with systemic absorption of steroids will also be recorded. Ethics and Dissemination The protocol was approved by the University Health Network Research Ethics Board (UHN REB number 15-9584-A). The results will be disseminated in peer-reviewed journals and at scientific

  19. Chromosome doubling method

    DOEpatents

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  20. Observing Double Stars

    NASA Astrophysics Data System (ADS)

    Genet, Russell M.; Fulton, B. J.; Bianco, Federica B.; Martinez, John; Baxter, John; Brewer, Mark; Carro, Joseph; Collins, Sarah; Estrada, Chris; Johnson, Jolyon; Salam, Akash; Wallen, Vera; Warren, Naomi; Smith, Thomas C.; Armstrong, James D.; McGaughey, Steve; Pye, John; Mohanan, Kakkala; Church, Rebecca

    2012-05-01

    Double stars have been systematically observed since William Herschel initiated his program in 1779. In 1803 he reported that, to his surprise, many of the systems he had been observing for a quarter century were gravitationally bound binary stars. In 1830 the first binary orbital solution was obtained, leading eventually to the determination of stellar masses. Double star observations have been a prolific field, with observations and discoveries - often made by students and amateurs - routinely published in a number of specialized journals such as the Journal of Double Star Observations. All published double star observations from Herschel's to the present have been incorporated in the Washington Double Star Catalog. In addition to reviewing the history of visual double stars, we discuss four observational technologies and illustrate these with our own observational results from both California and Hawaii on telescopes ranging from small SCTs to the 2-meter Faulkes Telescope North on Haleakala. Two of these technologies are visual observations aimed primarily at published "hands-on" student science education, and CCD observations of both bright and very faint doubles. The other two are recent technologies that have launched a double star renaissance. These are lucky imaging and speckle interferometry, both of which can use electron-multiplying CCD cameras to allow short (30 ms or less) exposures that are read out at high speed with very low noise. Analysis of thousands of high speed exposures allows normal seeing limitations to be overcome so very close doubles can be accurately measured.

  1. Post-Lyme disease syndrome

    PubMed Central

    Dąbek, Józefa; Cieślik, Paweł

    2015-01-01

    About 10% of patients with Lyme disease continue to experience musculoskeletal pain and cognitive dysfunction after recommended antibiotic treatment. This condition is called post-Lyme disease syndrome (PLDS) or post-treatment Lyme disease syndrome. These two terms are used interchangeably. The pathogenesis of PLDS has been controversial. The hypothesis that patients with PLDS may harbor hidden reservoirs of Borrelia burgdorferi after their initial antibiotic treatment is difficult to accept. The prospective, double-blind studies contradict this point of view. Also, recently published research applying xenodiagnosis to PLDS supports the opinion that PLDS most likely has an autoimmune background. Lengthy courses of antibiotics are not justified in patients with PLDS because of the lack of benefit, and they are fraught with hazards. Most patients with PLDS recover from persistent symptoms with time. However, it can take months before they feel completely well.

  2. Topological Quantum Double

    NASA Astrophysics Data System (ADS)

    Bonneau, Philippe

    Following a preceding paper showing how the introduction of a t.v.s. topology on quantum groups led to a remarkable unification and rigidification of the different definitions, we adapt here, in the same way, the definition of quantum double. This topological double is dualizable and reflexive (even for infinite dimensional algebras). In a simple case we show, considering the double as the "zero class" of an extension theory, the uniqueness of the double structure as a quasi-Hopf algebra. A la suite d'un précédent article montrant comment l'introduction d'une topologie d'e.v.t. sur les groupes quantiques permet une unification et une rigidification remarquables des différentes définitions, on adapte ici de la même manière la définition du double quantique. Ce double topologique est alors dualisable et reflexif (même pour des algèbres de dimension infinie). Dans un cas simple on montre, en considérant le double comme la "classe zéro" d'une théorie d'extensions, l'unicité de cette structure comme algèbre quasi-Hopf.

  3. Emerging double helical nanostructures

    NASA Astrophysics Data System (ADS)

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-07-01

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on `bottom-up' and `top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  4. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  5. Double aortic arch

    MedlinePlus

    ... double aortic arch may press on the windpipe (trachea) and esophagus, leading to trouble breathing and swallowing. ... to relieve pressure on the esophagus and windpipe (trachea). The surgeon ties off the smaller branch and ...

  6. PG 0308 + 096 and PG 1026 + 002 - Two new short period binary stars resulting from common-envelope evolution

    NASA Technical Reports Server (NTRS)

    Saffer, Rex A.; Wade, Richard A.; Liebert, James; Green, Richard F.; Sion, Edward M.; Bechtold, J.; Foss, Diana; Kidder, K.

    1993-01-01

    Ultraviolet spectroscopy, optical spectroscopy, and spectrophotometry have been used to study the excess UV stars PG 0308 + 096 and PG 1026 + 002. Both objects are short-period binary systems, each containing a DA white dwarf star and a dM star. Orbital periods of approximately 0.284 day for PG 0308 + 096, and aproximately 0.597 day for PG 1026, have been found by spectroscopic analysis of the H-alpha emission line. Ly-alpha and Balmer line profile fitting were used to estimate the mass of white dwarf stars; mass estimates for the dM stars are based on their spectral types. The orbital inclinations are derived from these masses, the periods, and amplitudes of the H-alpha radial velocity curves. The equivalent width of the H-alpha emission line, in each binary system, varies with the orbital phase in such a manner as to imply that it arises, in large part at least, from the hemisphere of the M star that faces the white dwarf star.

  7. A COMPREHENSIVE STUDY OF CLOSE DOUBLE WHITE DWARFS AS GRAVITATIONAL WAVE SOURCES: EVOLUTIONARY CHANNELS, BIRTH RATES, AND PHYSICAL PROPERTIES

    SciTech Connect

    Liu Jinzhong; Han Zhanwen; Zhang Fenghui; Zhang Yu

    2010-08-20

    Close double white dwarfs (CDWDs) are believed to dominate the Galactic gravitational wave (GW) radiation in the frequency range 10{sup -4} to 0.1 Hz, which will be detected by the Laser Interferometer Space Antenna (LISA) detector. The aim of this detector is to detect GW radiation from astrophysical sources in the universe and to help improve our understanding of the origin of the sources and their physical properties (masses and orbital periods). In this paper, we study the probable candidate sources in the Galaxy for the LISA detector: CDWDs. We use the binary population synthesis approach of CDWDs together with the latest findings of the synthesis models from Han, who proposed three evolutionary channels: (1) stable Roche lobe overflow plus common envelope (RLOF+CE), (2) CE+CE, and (3) exposed core plus CE. As a result, we systematically investigate the detailed physical properties (the distributions of masses, orbital periods, and chirp masses) of the CDWD sources for the LISA detector, examine the importance of the three evolutionary channels for the formation of CDWDs, and carry out Monte Carlo simulations. Our results show that RLOF+CE and CE+CE are the main evolutionary scenarios leading to the formation of CDWDs. For the LISA detectable sources, we also explore and discuss the importance of these three evolutionary channels. Using the calculated birth rate, we compare our results to the LISA sensitivity curve and the foreground noise floor of CDWDs. We find that our estimate for the number of CDWD sources that can be detected by the LISA detector is greater than 10,000. We also find that the detectable CDWDs are produced via the CE+CE channel and we analyze the fraction of the detectable CDWDs that are double helium (He+He), or carbon-oxygen plus helium (CO+He) WD binary systems.

  8. Dynamics of Double Stochastic Operators

    NASA Astrophysics Data System (ADS)

    Saburov, Mansoor

    2016-03-01

    A double stochastic operator is a generalization of a double stochastic matrix. In this paper, we study the dynamics of double stochastic operators. We give a criterion for a regularity of a double stochastic operator in terms of absences of its periodic points. We provide some examples to insure that, in general, a trajectory of a double stochastic operator may converge to any interior point of the simplex.

  9. Tracking The Double Eagle

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Last summer a trio of aeronauts made aviation history. Ben Abruzzo, Maxie Anderson and Larry Newman, all of Albuquerque, New Mexico, piloted their balloon Double Eagle I1 from Presque Isle, Maine to Miserey, France, some 50 miles from Paris. They were the first to negotiate a successful Atlantic crossing in a freeflying balloon after a score of attempts over a span of more than a century. A year earlier, Abruzzo and Anderson had made an unsuccessful try in their predecessor balloon Double Eagle. On that occasion, a NASA-developed satellite beacon helped save their lives. Carried aboard the balloon, the simple, seven-pound beacon continuously transmitted signals to NASA's Nimbus-6 satellite. Nimbus relayed the signals to monitors at Goddard Space Flight Center, enabling Goddard to compute the balloon's position. Position reports were then telephoned regularly to Double Eagle's control center at Bedford, Massachusetts. This monitoring system proved invaluable when the balloon encountered trouble several days after liftoff.

  10. Double Emulsion Templated Celloidosomes

    NASA Astrophysics Data System (ADS)

    Arriaga, Laura R.; Marquez, Samantha M.; Kim, Shin-Hyun; Chang, Connie; Wilking, Jim; Monroy, Francisco; Marquez, Manuel; Weitz, David A.

    2012-02-01

    We present a novel approach for fabricating celloidosomes, which represent a hollow and spherical three-dimensional self-assembly of living cells encapsulating an aqueous core. Glass- capillary microfluidics is used to generate monodisperse water-in-oil-in-water double emulsion templates using lipids as stabilizers. Such templates allow for obtaining single but also double concentric celloidosomes. In addition, after a solvent removal step the double emulsion templates turn into monodisperse lipid vesicles, whose membrane spontaneously phase separates when choosing the adequate lipid composition, providing the adequate scaffold for fabricating Janus-celloidosomes. These structures may find applications in the development of bioreactors in which the synergistic effects of two different types of cells selectively adsorbed on one of the vesicle hemispheres may be exploited.

  11. Double face sealing device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (Inventor)

    1991-01-01

    A double face sealing device for mounting between two surfaces to provide an airtight and fluid-tight seal between a closure member bearing one of the surfaces and a structure or housing bearing the other surface which extends around the opening or hatchway to be closed. The double face sealing device includes a plurality of sections or segments mounted to one of the surfaces, each having a main body portion, a pair of outwardly extending and diverging, cantilever, spring arms, and a pair of inwardly extending and diverging, cantilever, spring arms, an elastomeric cover on the distal, free, ends of the outwardly extending and diverging spring arms, and an elastomeric cover on the distal, free, ends of the inwardly extending and diverging spring arms. The double face sealing device has application or use in all environments requiring a seal, but is particularly useful to seal openings or hatchways between compartments of spacecraft or aircraft.

  12. Design friendly double patterning

    NASA Astrophysics Data System (ADS)

    Yesilada, Emek

    2012-03-01

    Double patterning using 193nm immersion has been adapted as the solution to enable 2x nm technology nodes until the arrival of EUV tools. As a result the past few years have seen a huge effort in creating double patterning friendly design flows. These flows have so far proposed a combination of decomposition rules at cell level and/or at placement level as well as sophisticated decomposition tools with varying density, design iteration and decomposition complexity penalties. What is more, designers have to familiarize themselves with double patterning challenges and decomposition tools. In this paper an alternative approach is presented that allows the development of dense standard cells with minimal impact on design flow due to double patterning. A real case study is done on 20nm node first metal layer where standard cells are designed without considering decomposition restrictions. The resulting layout is carefully studied in order to establish decomposition or color rules that can map the layout into two masks required for double patterning but without the need of complex coloring algorithms. Since the rules are derived from a decomposition unaware design they do not in return impose heavy restrictions on the design at the cell or placement level and show substantial density gains compared to previously proposed methods. Other key advantages are a simplified design flow without complex decomposition tools that can generate a faster time to market solution all at the same time keeping designers isolated from the challenges of the double patterning. The derived design rules highlight process development path required for design driven manufacturing.

  13. Double Bragg Interferometry.

    PubMed

    Ahlers, H; Müntinga, H; Wenzlawski, A; Krutzik, M; Tackmann, G; Abend, S; Gaaloul, N; Giese, E; Roura, A; Kuhl, R; Lämmerzahl, C; Peters, A; Windpassinger, P; Sengstock, K; Schleich, W P; Ertmer, W; Rasel, E M

    2016-04-29

    We employ light-induced double Bragg diffraction of delta-kick collimated Bose-Einstein condensates to create three symmetric Mach-Zehnder interferometers. They rely on (i) first-order, (ii) two successive first-order, and (iii) second-order processes which demonstrate the scalability of the corresponding momentum transfer. With respect to devices based on conventional Bragg scattering, these symmetric interferometers double the scale factor and feature a better suppression of noise and systematic uncertainties intrinsic to the diffraction process. Moreover, we utilize these interferometers as tiltmeters for monitoring their inclination with respect to gravity. PMID:27176520

  14. Double arch mirror study

    NASA Technical Reports Server (NTRS)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  15. Double Bragg Interferometry

    NASA Astrophysics Data System (ADS)

    Ahlers, H.; Müntinga, H.; Wenzlawski, A.; Krutzik, M.; Tackmann, G.; Abend, S.; Gaaloul, N.; Giese, E.; Roura, A.; Kuhl, R.; Lämmerzahl, C.; Peters, A.; Windpassinger, P.; Sengstock, K.; Schleich, W. P.; Ertmer, W.; Rasel, E. M.

    2016-04-01

    We employ light-induced double Bragg diffraction of delta-kick collimated Bose-Einstein condensates to create three symmetric Mach-Zehnder interferometers. They rely on (i) first-order, (ii) two successive first-order, and (iii) second-order processes which demonstrate the scalability of the corresponding momentum transfer. With respect to devices based on conventional Bragg scattering, these symmetric interferometers double the scale factor and feature a better suppression of noise and systematic uncertainties intrinsic to the diffraction process. Moreover, we utilize these interferometers as tiltmeters for monitoring their inclination with respect to gravity.

  16. Post-Adolescent Issues

    MedlinePlus

    Search COPING & HEALING CARING FOR A CHILD: POST-ADOLESCENT ISSUES As your child reaches adulthood, there will ... intake. New issues that you and your post adolescent child may want to discus together with his/ ...

  17. Double layers without current

    SciTech Connect

    Perkins, F.W.; Sun, Y.C.

    1980-11-01

    The steady-state solution of the nonlinear Vlasov-Poisson equations is reduced to a nonlinear eigenvalue problem for the case of double-layer (potential drop) boundary conditions. Solutions with no relative electron-ion drifts are found. The kinetic stability is discussed. Suggestions for creating these states in experiments and computer simulations are offered.

  18. Double resonator cantilever accelerometer

    DOEpatents

    Koehler, Dale R.

    1984-01-01

    A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

  19. Double resonator cantilever accelerometer

    DOEpatents

    Koehler, D.R.

    1982-09-23

    A digital quartz accelerometer includes a pair of spaced double-ended tuning forks fastened at one end to a base and at the other end through a spacer mass. Transverse movement of the resonator members stresses one and compresses the other, providing a differential frequency output which is indicative of acceleration.

  20. Double Trouble (Abstract)

    NASA Astrophysics Data System (ADS)

    Simonsen, M.

    2015-12-01

    (Abstract only) Variable stars with close companions can be difficult to accurately measure and characterize. The companions can create misidentifications, which in turn can affect the perceived magnitudes, amplitudes, periods, and colors of the variable stars. We will show examples of these Double Trouble stars and the impact their close companions have had on our understanding of some of these variable stars.

  1. Weathering the Double Whammy.

    ERIC Educational Resources Information Center

    Wellman, Jane V.

    2002-01-01

    Discusses how governing boards can help their institutions weather the "double-whammy" of doing more with less: identify the institution's short-term and long-term challenges; refocus the institution's mission, planning, and programming; assess and integrate the institution's tuition, aid, and outreach strategies; redouble the institution's…

  2. Sun Packs Double Punch

    NASA Video Gallery

    On August 3, the sun packed a double punch, emitting a M6.0-class flare at 9:43 am EDT. This video is of the second, slightly stronger M9.3-class flare at 11:41 pm EDT. Both flares had significant ...

  3. Double-Glazing Interferometry

    ERIC Educational Resources Information Center

    Toal, Vincent; Mihaylova, Emilia M.

    2009-01-01

    This note describes how white light interference fringes can be seen by observing the Moon through a double-glazed window. White light interferometric fringes are normally observed only in a well-aligned interferometer whose optical path difference is less than the coherence length of the light source, which is approximately one micrometer for…

  4. Rosette (Double Blossom)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rosette, or double blossom, is a serious disease of erect blackberries that is limited to the genus Rubus. Rosette may occur on trailing blackberries and dewberries, but rarely on red and black raspberries. In the United States, rosette occurs from New Jersey to Illinois and southwest to Texas and i...

  5. [Double ricochet marks].

    PubMed

    Sellier, K

    1987-01-01

    When bullets are flying stably and ricochet on a surface, only one mark is produced. In contrast yawing bullets can produce a double mark if the angle of incidence is sufficiently small (less than or equal to 5 degrees). Distances up to 15 cm were seen between the two marks. PMID:3660953

  6. A matterless double slit

    NASA Astrophysics Data System (ADS)

    King, Ben; di Piazza, Antonino; Keitel, Christoph H.

    2010-02-01

    Double slits provide incoming particles with a choice. Those that survive passage through the slits have chosen from two possible paths, which interfere to distribute them in a wave-like manner. Such wave-particle duality continues to be challenged and investigated in a broad range of disciplines with electrons, neutrons, helium atoms, C60 fullerenes, Bose-Einstein condensates and biological molecules. All variants have hitherto involved material constituents. We present a matterless double-slit scenario in which photons generated from virtual electron-positron pair annihilation in head-on collisions of a probe laser field with two ultra-intense laser beams form a double-slit interference pattern. Such electromagnetic fields are predicted to induce material-like behaviour in vacuum, supporting elastic scattering between photons. Our double-slit scenario presents, on the one hand, a realizable method with which to observe photon-photon scattering and, on the other hand, demonstrates the possibility of both controlling light with light and non-locally investigating features of the quantum vacuum structure.

  7. Teaching the Double Layer.

    ERIC Educational Resources Information Center

    Bockris, J. O'M.

    1983-01-01

    Suggests various methods for teaching the double layer in electrochemistry courses. Topics addressed include measuring change in absolute potential difference (PD) at interphase, conventional electrode potential scale, analyzing absolute PD, metal-metal and overlap electron PDs, accumulation of material at interphase, thermodynamics of electrified…

  8. Double-Entry Bookkeeping.

    ERIC Educational Resources Information Center

    Snyder, Herbert

    1999-01-01

    Explains the principles and mechanics of double-entry bookkeeping as a part of the accounting cycle to produce a functioning set of accounting records. Suggests that libraries need to have accurate and timely information about their spending to gain financial control and protect against fraud and abuse. (LRW)

  9. Double Marking Revisited

    ERIC Educational Resources Information Center

    Brooks, Val

    2004-01-01

    In 2002, the Qualifications and Curriculum Authority (QCA) published the report of an independent panel of experts into maintaining standards at Advanced Level (A-Level). One of its recommendations was for: limited experimental double marking of scripts in subjects such as English to determine whether the strategy would significantly reduce errors…

  10. Double Degrees: Double the Trouble or Twice the Return?

    ERIC Educational Resources Information Center

    Russell, A. Wendy; Dolnicar, Sara; Ayoub, Marina

    2008-01-01

    Double degrees (also called joint or combined degrees)--programs of study combining two bachelor degrees--are increasingly popular in Australian universities, particularly among women. A case study using qualitative and quantitative surveys of current and past double degree students is presented. The study indicates that double degrees benefit…

  11. Tests on Double Layer Metalization

    NASA Technical Reports Server (NTRS)

    Woo, D. S.

    1983-01-01

    28 page report describes experiments in fabrication of integrated circuits with double-layer metalization. Double-layer metalization requires much less silicon "real estate" and allows more flexibility in placement of circuit elements than does single-layer metalization.

  12. Measuring the Double Helix

    SciTech Connect

    Mathew-Fenn, R.S.; Das, R.; Harbury, P.A.B.

    2009-05-26

    DNA is thought to behave as a stiff elastic rod with respect to the ubiquitous mechanical deformations inherent to its biology. To test this model at short DNA lengths, we measured the mean and variance of end-to-end length for a series of DNA double helices in solution, using small-angle x-ray scattering interference between gold nanocrystal labels. In the absence of applied tension, DNA is at least one order of magnitude softer than measured by single-molecule stretching experiments. Further, the data rule out the conventional elastic rod model. The variance in end-to-end length follows a quadratic dependence on the number of base pairs rather than the expected linear dependence, indicating that DNA stretching is cooperative over more than two turns of the DNA double helix. Our observations support the idea of long-range allosteric communication through DNA structure.

  13. Double meningocele. Case report.

    PubMed

    Durmaz, R; Arslantaş, A; Ozön, Y H; Tel, E

    2000-01-01

    The coexistence of two distinct meningoceles of the spine is a very unusual event. We report a three-day-old boy with double meningoceles at the thoracic and lumbar levels. The connection between the stalk of the thoracic meningocele and the spinal cord, as seen on magnetic resonance imaging, showed a neurological involvement in this lesion. Our case is only the third without association of congenital anomalies or neurofibromatosis to be reported to date. PMID:11196754

  14. The double massa intermedia

    PubMed Central

    Baydin, Serhat; Gungor, Abuzer; Baran, Oguz; Tanriover, Necmettin; Rhoton, Albert L.

    2016-01-01

    Background: To describe the rare finding of a double massa intermedia (MI). Typically, the MI (interthalamic adhesion) is a single bridge of gray matter connecting the medial surfaces of the thalami. Methods: Twelve formalin- and alcohol-fixed human third ventricles were examined from superior to inferior by fiber dissection technique under ×6 to ×40 magnifications and with the endoscope. Results: In all hemispheres, the anterior and posterior commissure were defined. The MI, which bridges the medial surfaces of the thalami, was defined in all hemispheres. In one hemisphere, there was a second bridge between the thalami, located posteroinferior to the common MI. Endoscopic view confirmed that there was a second MI in this specimen. The MI usually traverses the third ventricle posterior to the foramen of Monro and connects the paired thalami. The MI is an important landmark during endoscopic and microscopic surgeries of the third ventricle. Although a double MI is very rare, surgeons should be aware of the possibility in their surgical planning. Conclusion: The surgeon should be aware of the possibility of a double MI to avoid confusion during third ventricle surgery. PMID:27127695

  15. Double face sealing device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce (Inventor)

    1991-01-01

    A double face sealing device is disclosed for mounting between two surfaces to provide an air-tight and fluid-tight seal between a closure member bearing one of the surfaces and a structure or housing bearing the other surface which extends around the opening or hatchway to be closed. The double face sealing device includes a plurality of sections or segments mounted to one of the surfaces, each having a main body portion, a pair of outwardly extending and diverging, cantilever, spring arms, and a pair of inwardly extending and diverging, cantilever, spring arms, an elastomeric cover on the distal, free ends of the outwardly extending and diverging spring arms, and an elastomeric cover on the distal, free, ends of the outwardly extending and diverging spring arms, and an elastomeric cover on the distal, free ends of the inwardly extending and diverging spring arms. The double face sealing device has application or use in all environments requiring a seal, but is particularly useful to seal openings or hatchways between compartments of spacecraft or aircraft.

  16. Colloidal Double Quantum Dots

    PubMed Central

    2016-01-01

    Conspectus Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole–dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single

  17. Colloidal Double Quantum Dots.

    PubMed

    Teitelboim, Ayelet; Meir, Noga; Kazes, Miri; Oron, Dan

    2016-05-17

    Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole-dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single photon

  18. 6. CONNECTION OF END POST AND TOP CHORD (TWO CHANNELS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. CONNECTION OF END POST AND TOP CHORD (TWO CHANNELS CONNECTED WITH COVER PLATES AND LACING BARS) WITH DIAGONALS (LOOP WELDED DOUBLE RECTILINEAR EYE BARS). - Daphna Creek Pratt Truss Bridge, State Route 1414, Holly Hill Street, Spanning Dahna Creek, Broadway, Rockingham County, VA

  19. English in Political Discourse of Post-Suharto Indonesia.

    ERIC Educational Resources Information Center

    Bernsten, Suzanne

    This paper illustrates increases in the use of English in political speeches in post-Suharto Indonesia by analyzing the phonological, morphological, and syntactic assimilation of loanwords (linguistic borrowing), as well as hybridization and code switching, and phenomena such as doubling and loan translations. The paper also examines the mixed…

  20. The Double Star mission

    NASA Astrophysics Data System (ADS)

    Liu, Z. X.; Escoubet, C. P.; Pu, Z.; Laakso, H.; Shi, J. K.; Shen, C.; Hapgood, M.

    2005-11-01

    The Double Star Programme (DSP) was first proposed by China in March, 1997 at the Fragrant Hill Workshop on Space Science, Beijing, organized by the Chinese Academy of Science. It is the first mission in collaboration between China and ESA. The mission is made of two spacecraft to investigate the magnetospheric global processes and their response to the interplanetary disturbances in conjunction with the Cluster mission. The first spacecraft, TC-1 (Tan Ce means "Explorer"), was launched on 29 December 2003, and the second one, TC-2, on 25 July 2004 on board two Chinese Long March 2C rockets. TC-1 was injected in an equatorial orbit of 570x79000 km altitude with a 28° inclination and TC-2 in a polar orbit of 560x38000 km altitude. The orbits have been designed to complement the Cluster mission by maximizing the time when both Cluster and Double Star are in the same scientific regions. The two missions allow simultaneous observations of the Earth magnetosphere from six points in space. To facilitate the comparison of data, half of the Double Star payload is made of spare or duplicates of the Cluster instruments; the other half is made of Chinese instruments. The science operations are coordinated by the Chinese DSP Scientific Operations Centre (DSOC) in Beijing and the European Payload Operations Service (EPOS) at RAL, UK. The spacecraft and ground segment operations are performed by the DSP Operations and Management Centre (DOMC) and DSOC in China, using three ground station, in Beijing, Shanghai and Villafranca.

  1. Quark-Novae in massive binaries: a model for double-humped, hydrogen-poor, superluminous Supernovae

    NASA Astrophysics Data System (ADS)

    Ouyed, Rachid; Leahy, Denis; Koning, Nico

    2015-12-01

    LSQ14bdq and SN 2006oz are superluminous, hydrogen-poor, SNe with double-humped light curves. We show that a Quark-Nova (QN; explosive transition of the Neutron Star - NS - to a quark star -QS) occurring in a massive binary, experiencing two Common Envelope (CE) phases, can quantitatively explain the light curves of LSQ14bdq and SN 2006oz. The more massive component (A) explodes first as a normal SN, yielding a NS which ejects the hydrogen envelope of the companion when the system enters its first CE phase. During the second CE phase, the NS spirals into and inflates the second He-rich CE. In the process it gains mass and triggers a QN, outside of the CO core, leaving behind a QS. The first hump in our model is the QN shock re-energizing the expanded He-rich CE. The QN occurs when the He-rich envelope is near maximum size (˜1000 R⊙) and imparts enough energy to unbind and eject the envelope. Subsequent merging of the QS with the CO core of component B, driven by gravitational radiation, turns the QS to a black hole. The ensuing black hole accretion provides sufficient power for the second brighter and long lasting hump. Our model suggests a possible connection between SLSNe-I and type Ic-BL SNe which occur when the QN is triggered inside the CO core. We estimate the rate of QNe in massive binaries during the second CE phase to be ˜5 × 10-5 of that of core-collapse SNe.

  2. The Double Chooz Experiment

    NASA Astrophysics Data System (ADS)

    Pfahler, Patrick; Double Chooz Collaboration

    2012-07-01

    Double Chooz is a reactor bar nue-disappearance experiment situated at the commercial nuclear power plant of Chooz in northern France. The experiment aims for the revelation of the last unknown mixing angle Θ13 as a part of the neutrino mixing matrix or the improvement of the upper limit for sin2(2Θ13), which is currently < 0.14 (90% CL). A newly developed gadolinium-loaded liquid scintillator as target allows the detection of electron-anti-neutrinos (bar nue) using the inverse beta decay and its distinct decay pattern (bar nue + p → e+ +n). Double Chooz uses two identical detectors at different distances in order to reduce systematic uncertainties. This will allow, after a data taking phase of 4 years, an improvement on sin2(2Θ13) down to < 0.03 (90% CL). The first (far) detector has successfully been installed and filled, and takes data since April of 2011. A preliminary analysis of first 120 days revealed about 4000 Neutrino-candidates and a stable detector-setup with low backgrounds. The commissioning of the second (near) detector is expected for the beginning of 2013 and will provide maximum sensitivity for the experiment.

  3. Double core evolution. 7: The infall of a neutron star through the envelope of its massive star companion

    NASA Technical Reports Server (NTRS)

    Terman, James L.; Taam, Ronald E.; Hernquist, Lars

    1995-01-01

    Binary systems with properties similar to those of high-mass X-ray binaries are evolved through the common envelope phase. Three-dimensional simulations show that the timescale of the infall phase of the neutron star depends upon the evolutionary state of its massive companion. We find that tidal torques more effectively accelerate common envelope evolution for companions in their late core helium-burning stage and that the infall phase is rapid (approximately several initial orbital periods). For less evolved companions the decay of the orbit is longer; however, once the neutron star is deeply embedded within the companion's envelope the timescale for orbital decay decreases rapidly. As the neutron star encounters the high-density region surrounding the helium core of its massive companion, the rate of energy loss from the orbit increases dramatically leading to either partial or nearly total envelope ejection. The outcome of the common envelope phase depends upon the structure of the evolved companion. In particular, it is found that the entire common envelope can be ejected by the interaction of the neutron star with a red supergiant companion in binaries with orbital periods similar to those of long-period Be X-ray binaries. For orbital periods greater than or approximately equal to 0.8-2 yr (for companions of mass 12-24 solar mass) it is likely that a binary will survive the common envelope phase. For these systems, the structure of the progenitor star is characterized by a steep density gradient above the helium core, and the common envelope phase ends with a spin up of the envelope to within 50%-60% of corotation and with a slow mass outflow. The efficiency of mass ejection is found to be approximately 30%-40%. For less evolved companions, there is insufficient energy in the orbit to unbind the common envelope and only a fraction of it is ejected. Since the timescale for orbital decay is always shorter than the mass-loss timescale from the common envelope

  4. Double layers and electrostatic shocks

    NASA Technical Reports Server (NTRS)

    Hershkowitz, N.

    1981-01-01

    It is shown that it is useful to define double layers and shocks so that the ion phase spaces of double layers are the mirror image (about zero ion velocity) of the ion phase spaces for laminar electrostatic shocks. The distinguishing feature is the direction of the free ion velocity. It is also shown that double layers can exist without the presence of trapped ions. The Bohm condition for double layers, that the ion drift velocity on the high potential side must be greater than the ion sound velocity, is shown to be related to a requirement of a lower limit on the Mach number of laminar electrostatic shocks

  5. Colored Flag by Double Refraction.

    ERIC Educational Resources Information Center

    Reid, Bill

    1994-01-01

    Describes various demonstrations that illustrate double refraction and rotation of the plane of polarization in stressed, transparent plastics, with the consequent production of colored designs. (ZWH)

  6. Apple Valley Double Star Workshop

    NASA Astrophysics Data System (ADS)

    Brewer, Mark

    2015-05-01

    The High Desert Astronomical Society hosts an annual double star workshop, where participants measure the position angles and separations of double stars. Following the New Generation Science Standards (NGSS), adopted by the California State Board of Education, participants are assigned to teams where they learn the process of telescope set-up and operation, the gathering of data, and the reduction of the data. Team results are compared to the latest epoch listed in the Washington Double Star Catalog (WDS) and papers are written for publication in the Journal of Double Star Observations (JDSO). Each team presents a PowerPoint presentation to their peers about actual hands-on astronomical research.

  7. Strain balanced quantum posts

    SciTech Connect

    Alonso-Alvarez, D.; Alen, B.; Ripalda, J. M.; Llorens, J. M.; Taboada, A. G.; Briones, F.; Roldan, M. A.; Hernandez-Saz, J.; Hernandez-Maldonado, D.; Herrera, M.; Molina, S. I.

    2011-04-25

    Quantum posts are assembled by epitaxial growth of closely spaced quantum dot layers, modulating the composition of a semiconductor alloy, typically InGaAs. In contrast with most self-assembled nanostructures, the height of quantum posts can be controlled with nanometer precision, up to a maximum value limited by the accumulated stress due to the lattice mismatch. Here, we present a strain compensation technique based on the controlled incorporation of phosphorous, which substantially increases the maximum attainable quantum post height. The luminescence from the resulting nanostructures presents giant linear polarization anisotropy.

  8. Dual double field theory

    NASA Astrophysics Data System (ADS)

    Bergshoeff, Eric A.; Hohm, Olaf; Penas, Victor A.; Riccioni, Fabio

    2016-06-01

    We present the dual formulation of double field theory at the linearized level. This is a classically equivalent theory describing the duals of the dilaton, the Kalb-Ramond field and the graviton in a T-duality or O( D, D) covariant way. In agreement with previous proposals, the resulting theory encodes fields in mixed Young-tableau representations, combining them into an antisymmetric 4-tensor under O( D, D). In contrast to previous proposals, the theory also requires an antisymmetric 2-tensor and a singlet, which are not all pure gauge. The need for these additional fields is analogous to a similar phenomenon for "exotic" dualizations, and we clarify this by comparing with the dualizations of the component fields. We close with some speculative remarks on the significance of these observations for the full non-linear theory yet to be constructed.

  9. Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Cremonesi, Oliviero

    2016-05-01

    After more than 3/4 of century from its proposal, Neutrinoless Double Beta Decay (NLDBD) is still missing observation and continues to represent the only practical method for investigating the Dirac/Majorana nature of neutrinos. In case neutrinos would be Majorana particles, NLDBD would provide unique informations on their properties (absolute mass scale and Majorana phases). Boosted by the discovery of neutrino oscillations, a number of experiments with improved sensitivity have been proposed in the past decade. Some of them have recently started operation and others are ready to start. They will push the experimental sensitivity on the decay halflife beyond 1026 year, starting to analyze the region of the inverted mass hierarchy. The status and perspectives of the ongoing experimental effort are reviewed. Uncertainties coming from the calculation othe decay nuclear matrix elements (NME) as well as the recently suggested possibility of a relevant quenching of the axial coupling constant are also discussed.

  10. Double layer secure sketch

    NASA Astrophysics Data System (ADS)

    Li, Cai

    2012-09-01

    Secure sketch has been applied successfully in a wide variety of applications like cryptography, biometric authentication systems and so on. All of these secure sketches have properties in common namely error-tolerance and small entropy loss. The former ensures an input set w' can unlock the system if w' is substantially overlapped with a template set w while the latter means it is hard for an adversary to get the information of w even with the knowledge of s, which is produced by w and stored in the system publicly. In their constructions, they all consider w as a set of atomic elements. However, in the real word, it is very likely the elements in the template set are sets as well. In this paper, we propose a double layer secure sketch to address this issue.

  11. Doubled Color Codes

    NASA Astrophysics Data System (ADS)

    Bravyi, Sergey

    Combining protection from noise and computational universality is one of the biggest challenges in the fault-tolerant quantum computing. Topological stabilizer codes such as the 2D surface code can tolerate a high level of noise but implementing logical gates, especially non-Clifford ones, requires a prohibitively large overhead due to the need of state distillation. In this talk I will describe a new family of 2D quantum error correcting codes that enable a transversal implementation of all logical gates required for the universal quantum computing. Transversal logical gates (TLG) are encoded operations that can be realized by applying some single-qubit rotation to each physical qubit. TLG are highly desirable since they introduce no overhead and do not spread errors. It has been known before that a quantum code can have only a finite number of TLGs which rules out computational universality. Our scheme circumvents this no-go result by combining TLGs of two different quantum codes using the gauge-fixing method pioneered by Paetznick and Reichardt. The first code, closely related to the 2D color code, enables a transversal implementation of all single-qubit Clifford gates such as the Hadamard gate and the π / 2 phase shift. The second code that we call a doubled color code provides a transversal T-gate, where T is the π / 4 phase shift. The Clifford+T gate set is known to be computationally universal. The two codes can be laid out on the honeycomb lattice with two qubits per site such that the code conversion requires parity measurements for six-qubit Pauli operators supported on faces of the lattice. I will also describe numerical simulations of logical Clifford+T circuits encoded by the distance-3 doubled color code. Based on a joint work with Andrew Cross.

  12. 19. GROUND STORY, POST OFFICE LOBBY DETAIL OF POST OFFICE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. GROUND STORY, POST OFFICE LOBBY DETAIL OF POST OFFICE BOXES ALONG WEST WALL OF LEXINGTON AVENUE ARM - Grand Central Post Office Annex, Forty-fifth Street & Lexington Avenue, Southwest corner, New York County, NY

  13. 16. FLOOR 1; MASSIVE CENTER POST IS THE MAIN POST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. FLOOR 1; MASSIVE CENTER POST IS THE MAIN POST OF A 1736 POST MILL WHICH THIS MILL REPLACED; MORTISE FOR QUARTER BAR CAN BE SEEN - Hook Windmill, North Main Street at Pantigo Road, East Hampton, Suffolk County, NY

  14. Spatio-kinematic modelling of Abell 65, a double-shelled planetary nebula with a binary central star

    NASA Astrophysics Data System (ADS)

    Huckvale, L.; Prouse, B.; Jones, D.; Lloyd, M.; Pollacco, D.; López, J. A.; O'Brien, T. J.; Sabin, L.; Vaytet, N. M. H.

    2013-09-01

    We present the first detailed spatio-kinematical analysis and modelling of the planetary nebula Abell 65, which is known to host a post-common envelope, binary, central star system. As such, this object is of great interest in studying the link between nebular morphology and central star binarity. [O III]5007 Å and Hα+[N II]6584 Å longslit spectra and imagery of Abell 65 were obtained with the Manchester Échelle Spectrometer on the 2.1-m telescope at the San Pedro Martír Observatory (MES-SPM). Further [O III]5007 Å longslit spectra were obtained with the Ultraviolet and Visual Échelle Spectrograph on the Very Large Telescope (VLT-UVES). These data were used to develop a spatio-kinematical model for the [O III]5007 Å emission from Abell 65. A `best-fitting' model was found by comparing synthetic spectra and images rendered from the model to the data. The model comprises an outer shell and an inner shell, with kinematical ages of 15000 ± 5000 yr kpc-1 and 8000 ± 3000 yr kpc-1, respectively. Both shells have peanut-shaped bipolar structures with symmetry axes at inclinations of (55 ± 10)° (to the line of sight) for the outer shell and (68 ± 10)° for the inner shell. The near alignment between the nebular shells and the binary orbital inclination [of (68 ± 2)°] is strongly indicative that the binary is responsible for shaping the nebula. Abell 65 is one of a growing number of planetary nebulae (seven to date, including Abell 65 itself) for which observations and modelling support the shaping influence of a central binary.

  15. CRITICALITY SAFETY POSTING GUIDELINES

    SciTech Connect

    JENSEN, M.A.

    2001-11-01

    This document provides a set of guidelines in the preparation of criticality safety postings. Guidance is provided in word choice, word arrangement, common human factors considerations. and use of color to highlight limits, cautions, and permissives.

  16. Post and Lintel Architecture

    ERIC Educational Resources Information Center

    Daniel, Robert A.

    1973-01-01

    Author finds that children understand architectural concepts more readily when he refers to familiar non-architectural examples of them such as goal posts, chairs, tables, and playground equipment. (GB)

  17. Post-Polio Syndrome

    MedlinePlus

    ... Funding Information Research Programs Training & Career Awards Enhancing Diversity Find People About NINDS NINDS Post-Polio Syndrome ... News From NINDS | Find People | Training | Research | Enhancing Diversity Careers@NINDS | FOIA | Accessibility Policy | Contact Us | Privacy ...

  18. Cryogenic skirt support post

    NASA Astrophysics Data System (ADS)

    Niemann, R. C.; Buckles, W. E.

    The cold masses of cryostats having vertical axes, like vertical pressure vessels, can be effectively supported by means of a cylindrical skirt that wraps concentrically around the cold mass. The skirt is a cryogenic support post connected at its upper end to the cold mass and at its lower end to the cryostat vacuum vessel. A heat intercept connection to an intermediate temperature refrigeration source can be employed to control heat leak. The support post consists of a composite; e.g. epoxy fibreglass, or cylinder with bolted or thermal interference fit end connections. The support post, being a single element support, simplifies cryostat assembly and alignment. The composite cylinder, with a relatively large diameter, lends itself to structural soundness and stability under both static and dynamic loading conditions. Its relatively long length and intermediate temperature heat intercept allows low heat leak to the cold mass. The details of the design of a cryogenic skirt support post as applied to a superconducting magnetic energy storage cryostat are presented. Included are support post fabrication, cryostat assembly, and predicted structural and thermal performance. Fabrication of and operational experiences with a prototype support post assembly are discussed.

  19. The double-mode Cepheids

    NASA Astrophysics Data System (ADS)

    Balona, L. A.

    1985-06-01

    Recent observational and theoretical results on double-mode Cepheids are reviewed. The likelihood that recently proposed candidate Cepheids are indeed Cepheids is evaluated. Periods, period ratios, and semi-amplitudes of the light and radial velocity variations of double-mode Cepheids are given. The physical and pulsational properties of double-mode Cepheids are discussed, reviewing evidence that these stars are Population I objects of high mass and that they all have the same mean effective temperature. The discovery of strong H-alpha emission occurring at seemingly random phases is addressed. Attempts to resolve the mass discrepancy problem of double-mode Cepheids, which results from observations showing that these Cepheids are indistinguishable from normal Cepheids of similar period, are reviewed along with attempts to find the cause of double-mode pulsation.

  20. Supported double membranes

    PubMed Central

    Murray, David H.; Tamm, Lukas K.; Kiessling, Volker

    2009-01-01

    Planar model membranes, like supported lipid bilayers and surface-tethered vesicles, have been proven to be useful tools for the investigation of complex biological functions in a significantly less complex membrane environment. In this study, we introduce a supported double membrane system that should be useful for studies that target biological processes in the proximity of two lipid bilayers such as the periplasm of bacteria and mitochondria or the small cleft between pre-and postsynaptic neuronal membranes. Large unilamellar vesicles (LUV) were tethered to a preformed supported bilayer by a biotin-streptavidin tether. We show from single particle tracking (SPT) experiments that these vesicle are mobile above the plane of the supported membrane. At higher concentrations, the tethered vesicles fuse to form a second continuous bilayer on top of the supported bilayer. The distance between the two bilayers was determined by fluorescence interference contrast (FLIC) microscopy to be between 16 and 24 nm. The lateral diffusion of labeled lipids in the second bilayer was very similar to that in supported membranes. SPT experiments with reconstituted syntaxin-1A show that the mobility of transmembrane proteins was not improved when compared with solid supported membranes. PMID:19236921

  1. Laser double Doppler flowmeter

    NASA Astrophysics Data System (ADS)

    Poffo, L.; Goujon, J.-M.; Le Page, R.; Lemaitre, J.; Guendouz, M.; Lorrain, N.; Bosc, D.

    2014-05-01

    The Laser Doppler flowmetry (LDF) is a non-invasive method for estimating the tissular blood flow and speed at a microscopic scale (microcirculation). It is used for medical research as well as for the diagnosis of diseases related to circulatory system tissues and organs including the issues of microvascular flow (perfusion). It is based on the Doppler effect, created by the interaction between the laser light and tissues. LDF measures the mean blood flow in a volume formed by the single laser beam, that penetrate into the skin. The size of this measurement volume is crucial and depends on skin absorption, and is not directly reachable. Therefore, current developments of the LDF are focused on the use of always more complex and sophisticated signal processing methods. On the other hand, laser Double Doppler Flowmeter (FL2D) proposes to use two laser beams to generate the measurement volume. This volume would be perfectly stable and localized at the intersection of the two laser beams. With FL2D we will be able to determine the absolute blood flow of a specific artery. One aimed application would be to help clinical physicians in health care units.

  2. Latest Double Chooz results

    NASA Astrophysics Data System (ADS)

    Lasserre, Thierry; Double Chooz Collaboration

    2016-05-01

    I report the latest results from the Double Chooz experiment on the θ13 neutrino mixing angle. Two detectors are located at distances of 400 m and 1050 m from the reactor cores of the Chooz nuclear power station (France) to measure the disappearance of electron antineutrinos. The far detector has been taking data since 2011, accumulating a live time of 467.90 days (66.5 GW-ton-year). In this article we focus on the latest measurement using neutrino-induced neutron capture on hydrogen. A new analysis improved the signal efficiency and reduced the backgrounds and systematic uncertainties, leading to sin2 2θ 13 = 0.095+0.039 -0.038. When combined with the Gadolinium-based analysis this leads to sin2 2θ13 = 0.088+0.33 -0.033. The distortion from the prediction above a visible energy of 4 MeV is confirmed. The near detector started data taking in 2014 and first results shall be reported in 2016.

  3. Double acting bit holder

    DOEpatents

    Morrell, Roger J.; Larson, David A.; Ruzzi, Peter L.

    1994-01-01

    A double acting bit holder that permits bits held in it to be resharpened during cutting action to increase energy efficiency by reducing the amount of small chips produced. The holder consist of: a stationary base portion capable of being fixed to a cutter head of an excavation machine and having an integral extension therefrom with a bore hole therethrough to accommodate a pin shaft; a movable portion coextensive with the base having a pin shaft integrally extending therefrom that is insertable in the bore hole of the base member to permit the moveable portion to rotate about the axis of the pin shaft; a recess in the movable portion of the holder to accommodate a shank of a bit; and a biased spring disposed in adjoining openings in the base and moveable portions of the holder to permit the moveable portion to pivot around the pin shaft during cutting action of a bit fixed in a turret to allow front, mid and back positions of the bit during cutting to lessen creation of small chip amounts and resharpen the bit during excavation use.

  4. Pion double charge exchange reactions leading to double pionic atoms

    SciTech Connect

    Nieves, J.; Oset, E.; Vincente-Vacas, M.J. ); Hirenzaki, S.; Toki, H. )

    1992-10-20

    In this paper, the authors study theoretically pion double charge exchange reactions leading to double pionic atoms. The reaction cross-sections with two pions in the deeper bound pionic orbits in [sup 208]Pb are calculated with realistic pionic atom wave functions and distortion effects. The cross-sections are found to be d[sup 2] [sigma]/dEd[Omega] [approx] 10[sup [minus] 3] [minus] 10[sup [minus] 4] [mu]b/srMeV, which are only a small fraction of the double charge exchange.

  5. Double Radio Sources: Two Approaches

    NASA Astrophysics Data System (ADS)

    Valtonen, M. J.; Heinämäki, P.

    2000-02-01

    The theory of double radio sources is considered from two different points of view: the so called unified models and the slingshot model. First, observations and theory are discussed in 11 areas: (1) the dependence or independence of small-scale and large-scale jets from each other; (2) stability and existence of large-scale jets; (3) radio hot spots inside the lobes of double radio sources; (4) the relation of double-lobed quasars to radio galaxies; (5) polarization and other asymmetries between the two lobes and correlations among them; (6) the speeds of advance of radio lobes; (7) giant radio sources; (8) one-sided double radio sources; (9) multiple-sided double radio sources; (10) the origin of the Fanaroff-Riley classes of radio morphology; and (11) the origin of distance asymmetries of the radio lobes. Then five steps in building up a double radio source theory are discussed: (1) theory of galaxy mergers; (2) theory of black hole mergers; (3) theory of black hole interactions and ejections; (4) theory of radio lobe formation and evolution; and (5) radio jet theory. Finally, recent X-ray observations by ROSAT are discussed from the point of view of double radio source theory.

  6. Post-ERCP pancreatitis.

    PubMed

    Arata, Shinju; Takada, Tadahiro; Hirata, Koichi; Yoshida, Masahiro; Mayumi, Toshihiko; Hirota, Morihisa; Yokoe, Masamichi; Hirota, Masahiko; Kiriyama, Seiki; Sekimoto, Miho; Amano, Hodaka; Wada, Keita; Kimura, Yasutoshi; Gabata, Toshifumi; Takeda, Kazunori; Kataoka, Keisho; Ito, Tetsuhide; Tanaka, Masao

    2010-01-01

    Pancreatitis remains the most common severe complication of endoscopic retrograde cholangiopancreatography (ERCP). Detailed information about the findings of previous studies concerning post-ERCP pancreatitis has not been utilized sufficiently. The purpose of the present article was to present guidelines for the diagnostic criteria of post-ERCP pancreatitis, and its incidence, risk factors, and prophylactic procedures that are supported by evidence. To achieve this purpose, a critical examination was made of the articles on post-ERCP pancreatitis, based on the data obtained by research studies published up to 2009. At present, there are no standardized diagnostic criteria for post-ERCP pancreatitis. It is appropriate that post-ERCP pancreatitis is defined as acute pancreatitis that has developed following ERCP, and its diagnosis and severity assessment should be made according to the diagnostic criteria and severity assessment of the Japanese Ministry of Health, Labour and Welfare. The incidence of acute pancreatitis associated with diagnostic and therapeutic ERCP is 0.4-1.5 and 1.6-5.4%, respectively. Endoscopic papillary balloon dilation is associated with a high risk of acute pancreatitis compared with endoscopic sphincterotomy. It was made clear that important risk factors include dysfunction of the Oddi sphincter, being of the female sex, past history of post-ERCP pancreatitis, and performance of pancreaticography. Temporary prophylactic placement of pancreatic stents in the high-risk group is useful for the prevention of post-ERCP pancreatitis [odds ratio (OR) 3.2, 95% confidence interval (CI) 1.6-6.4, number needed to treat (NNT) 10]. Use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with a reduction in the development of post-ERCP pancreatitis (OR 0.46, 95% CI 0.32-0.65). Single rectal administration of NSAIDs is useful for the prevention of post-ERCP pancreatitis [relative risk (RR) 0.36, 95% CI 0.22-0.60, NNT 15] and decreases the

  7. Advanced double layer capacitors

    NASA Technical Reports Server (NTRS)

    Sarangapani, S.; Lessner, P.; Forchione, J.; Laconti, A. B.

    1989-01-01

    There is a need for large amounts of power to be delivered rapidly in a number of airborne and space systems. Conventional, portable power sources, such as batteries, are not suited to delivering high peak power pulses. The charge stored at the electrode-electrolyte double layer is, however, much more assessible on a short time scale. Devices exploiting this concept were fabricated using carbon and metal oxides (Pinnacle Research) as the electrodes and sulfuric acid as the electrolyte. The approach reported, replaces the liquid sulfuric acid electrolyte with a solid ionomer electrolyte. The challenge is to form a solid electrode-solid ionomer electrolyte composite which has a high capacitance per geometric area. The approach to maximize contact between the electrode particles and the ionomer was to impregnate the electrode particles using a liquid ionomer solution and to bond the solvent-free structure to a solid ionomer membrane. Ruthenium dioxide is the electrode material used. Three strategies are being pursued to provide for a high area electrode-ionomer contact: mixing of the RuOx with a small volume of ionomer solution followed by filtration to remove the solvent, and impregnation of the ionomer into an already formed RuOx electrode. RuOx powder and electrodes were examined by non-electrochemical techniques. X-ray diffraction has shown that the material is almost pure RuO2. The electrode structure depends on the processing technique used to introduce the Nafion. Impregnated electrodes have Nafion concentrated near the surface. Electrodes prepared by the evaporation method show large aggregates of crystals surrounded by Nafion.

  8. [Post bariatric body contouring.

    PubMed

    Winge, Rikke; Henriksen, Trine Foged; Printzlau, Andreas; Hülmich, Lisbet

    2014-03-17

    Post bariatric body contouring in Denmark is currently a field under development. The scope of this article is to give an overview of existing plastic surgery techniques being used to treat patients with massive weight loss, as well as the current indications for patient referral. Furthermore, we describe how to optimise the preoperative evaluation of the patient and give a brief description of potential surgical adverse effects and their prevalence. Further research can provide this field with invaluable data regarding the post-operative effects on patient rehabilitation and quality of life. PMID:25096208

  9. Three step double layers in the laboratory

    NASA Astrophysics Data System (ADS)

    Bailey, Andrew, III; Hershkowitz, Noah

    1988-01-01

    A new class of stationary double layer structure, with three or more distinct steps, is demonstrated in the laboratory. A large monotonic potential increase results from a series of smaller double layers. In many respects, these double layer structures resemble those inferred from satellite measurements of auroral double layers. This new class of double layer appears to depend on turbulence for its existence and to be a hybrid structure, intermediate between anomalous resistivity and BGK double layers.

  10. Entanglement purification with double selection

    SciTech Connect

    Fujii, Keisuke; Yamamoto, Katsuji

    2009-10-15

    We investigate an entanglement purification protocol with double-selection process, which works under imperfect local operations. Compared with the usual protocol with single selection, this double-selection method has higher noise thresholds for the local operations and quantum communication channels and achieves higher fidelity of purified states. It also provides a yield comparable to that of the usual protocol with single selection. We discuss on general grounds how some of the errors which are introduced by local operations are left as intrinsically undetectable. The undetectable errors place a general upper bound on the purification fidelity. The double selection is a simple method to remove all the detectable errors in the first order, so that the upper bound on the fidelity is achieved in the low-noise regime. The double selection is further applied to purification of multipartite entanglement such as two-colorable graph states.

  11. Species doubling and effective Lagrangians

    SciTech Connect

    Creutz, M.; Tytgat, M.

    1996-09-01

    Coupling gauge fields to the chiral currents from an effective Lagrangian for pseudoscalar mesons naturally gives rise to a species doubling phenomenon similar to that seen with fermionic fields in lattice gauge theory. 17 refs.

  12. A Double Pendulum "Art Machine"

    ERIC Educational Resources Information Center

    Romer, R. H.

    1970-01-01

    Describes a double pendulum apparatus and its mode of operation to produce a great variety of figures similar to Lissajous figures. The author suggests that several advanced physics topics can be studied with the aid of this instrument. Bibliography. (LC)

  13. Simulation of auroral double layers

    NASA Technical Reports Server (NTRS)

    Hubbard, R. F.; Joyce, G.

    1979-01-01

    Some basic properties of plasma double layers are deduced from a particle-in-cell computer simulation and related to parallel electric-field structures above the auroral regions. The simulation results on the processes leading to double-layer formation are examined, particularly in relation to the transient stage and double-layer structure and stability. It is concluded that: (1) a large potential difference applied to a finite-length plasma will be concentrated in a shocklike localized region instead of occurring over the entire length of the system; (2) the initial stage in double-layer formation is dominated by a large-potential pulse propagating in the direction of the induced electrostatic drift; (3) the entire potential is dropped over a specific scale length once the double layer has formed; and (4) this scale length is expected to be of the order of 1 km for a double layer above a discrete auroral arc with a potential of 10 kV and the electric-field vector parallel to the magnetic-field vector.

  14. Effects of a single administration of prostaglandin F2alpha, or a combination of prostaglandin F2alpha and prostaglandin E2, or placebo on fertility variables in dairy cows 3–5 weeks post partum, a randomized, double-blind clinical trial

    PubMed Central

    Hirsbrunner, Gaby; Burkhardt, Heinz W; Steiner, Adrian

    2006-01-01

    Background Delayed uterine involution has negative effects on the fertility of cows; use of prostaglandin F2alpha alone as a single treatment has not been shown to consistently improve fertility. Combined administration of PGF2alpha and PGE2 increased uterine pressure in healthy cows. We hypothesized, that the combination of both prostaglandins would accelerate uterine involution and have, therefore, a positive effect on fertility variables. In commercial dairy farming, the benefit of a single post partum combined prostaglandin treatment should be demonstrated. Methods 383 cows from commercial dairy farms were included in this study. Uterine size and secretion were evaluated at treatment 21–35 days post partum and 14 days later. Cows were randomly allocated to one of three treatment groups: PGF2alpha and PGE2, PGF2alpha or placebo. For every animal participating in the study, the following reproduction variables were recorded: Interval from calving to first insemination, days open, number of artificial inseminations (AI) to conception; subsequent treatment of uterus, subsequent treatment of ovaries. Plasma progesterone level at time of treatment was used as a covariable. For continuous measurements, analysis of variance was performed. Fisher's exact test for categorical non-ordered data and exact Kruskal-Wallis test for ordered data were used; pairwise group comparisons with Bonferroni adjustment of significance level were performed. Results There was no significant difference among treatment groups in uterine size. Furthermore, there was no significant difference among treatments concerning days open, number of AI, and subsequent treatment of uterus and ovaries. Days from calving to first insemination tended to be shorter for cows with low progesterone level given PGF2alpha and PGE2 in combination than for the placebo-group (P = 0.024). Conclusion The results of this study indicate that the administration of PGF2alpha or a combination of PGF2alpha and PGE2 21 to

  15. The double burden.

    PubMed

    Faurholt-Jepsen, Daniel

    2013-07-01

    parameters. The population was followed up during treatment (2 and 5 months) to assess treatment outcome as well as after one year to assess their survival status. Based on data from 1,250 tuberculosis patients and 350 neighbourhood controls, we found that 38 and 21%, respectively, had impaired glycaemia, and that the prevalence of diabetes was 17 and 9% among tuberculosis patients and controls, respectively. This difference in prevalence between patients and controls was equivalent to an adjusted odds ratio of more than four, indicating a strong association between tuberculosis and diabetes. Furthermore, we found that diabetes was associated with tuberculosis among both participants with or without HIV co-infection. Despite the strong association, diabetes had only moderate clinical implications when the tuberculosis patients initiated the tuberculosis treatment; the patients with diabetes co-morbidity had a minor elevation in the immune response and more frequently reported to have fever. Furthermore, diabetes did not seem to delay time to sputum conversion during treatment. Nevertheless, diabetes co-morbidity led to impaired treatment outcome with slower recovery of weight and haemoglobin and a more than four times higher mortality rate within the initial phase of tuberculosis treatment. In conclusion, in the African region, the double burden of tuberculosis and diabetes is becoming a major health problem. Although the tuberculosis incidence has stabilized during the last decade, the increasing incidence of diabetes will possibly interfere with tuberculosis control and may, consequently, make the tuberculosis incidence increase again. Future research strategies should focus on enhanced diagnostic tools to identify tuberculosis patients with diabetes co-morbidity, and on the role of disease-disease, drug-disease and drug-drug interactions between tuberculosis and diabetes diseases and treatments. PMID:23809978

  16. Early (≤ 1-h) vs. late (>1-h) administration of frovatriptan plus dexketoprofen combination vs. frovatriptan monotherapy in the acute treatment of migraine attacks with or without aura: a post hoc analysis of a double-blind, randomized, parallel group study.

    PubMed

    Allais, Gianni; Bussone, Gennaro; Tullo, Vincenzo; Cortelli, Pietro; Valguarnera, Fabio; Barbanti, Piero; Sette, Giuliano; Frediani, Fabio; D'Arrigo, Giacomo; d'Onofrio, Florindo; Comi, Giancarlo; Curone, Marcella; Colombo, Bruno; Omboni, Stefano; Benedetto, Chiara

    2015-05-01

    The early use of triptan in combination with a nonsteroidal anti-inflammatory drug after headache onset may improve the efficacy of acute migraine treatment. In this retrospective analysis of a randomized, double-blind, parallel group study, we assessed the efficacy of early or late intake of frovatriptan 2.5 mg + dexketoprofen 25 or 37.5 mg (FroDex 25 and FroDex 37.5) vs. frovatriptan 2.5 mg alone (Frova) in the acute treatment of migraine attacks. In this double-blind, randomized parallel group study 314 subjects with acute migraine with or without aura were randomly assigned to Frova, FroDex 25, or FroDex 37.5. Pain free (PF) at 2-h (primary endpoint), PF at 4-h and pain relief (PR) at 2 and 4-h, speed of onset at 60, 90, 120 and 240-min, and sustained pain free (SPF) at 24-h were compared across study groups according to early (≤1-h; n = 220) or late (>1-h; n = 59) intake. PF rates at 2 and 4-h were significantly larger with FroDex 37.5 vs. Frova (early intake, n = 71 FroDex 37.5 and n = 75 Frova: 49 vs. 32 % and 68 vs. 52 %, p < 0.05; late intake, n = 20 Frodex 37.5, and n = 18 Frova: 55 vs. 17 %, p < 0.05 and 85 vs. 28 %, p < 0.01). Also with FroDex 25, in the early intake group (n = 74) PF episodes were significantly higher than Frova. PR at 2 and 4-h was significantly better under FroDex 37.5 than Frova (95 % vs. 50 %, p < 0.001, 100 % vs. 72 %, p < 0.05) in the late intake group (n = 21). SPF episodes at 24-h after early dosing were 25 % (Frova), 45 % (FroDex 25) and 41 % (FroDex 37.5, p < 0.05 combinations vs. monotherapy), whereas they were not significantly different with late intake. All treatments were equally well tolerated. FroDex was similarly effective regardless of intake timing from headache onset. PMID:26017535

  17. The double loop mattress suture

    PubMed Central

    Biddlestone, John; Samuel, Madan; Creagh, Terry; Ahmad, Tariq

    2014-01-01

    An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p ≤ 0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p ≤ 0.001). Wound gapping is equal, and wound eversion appears significantly improved (p ≤ 0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines. PMID:24698436

  18. Double metric, generalized metric, and α' -deformed double field theory

    NASA Astrophysics Data System (ADS)

    Hohm, Olaf; Zwiebach, Barton

    2016-03-01

    We relate the unconstrained "double metric" of the "α' -geometry" formulation of double field theory to the constrained generalized metric encoding the spacetime metric and b -field. This is achieved by integrating out auxiliary field components of the double metric in an iterative procedure that induces an infinite number of higher-derivative corrections. As an application, we prove that, to first order in α' and to all orders in fields, the deformed gauge transformations are Green-Schwarz-deformed diffeomorphisms. We also prove that to first order in α' the spacetime action encodes precisely the Green-Schwarz deformation with Chern-Simons forms based on the torsionless gravitational connection. This seems to be in tension with suggestions in the literature that T-duality requires a torsionful connection, but we explain that these assertions are ambiguous since actions that use different connections are related by field redefinitions.

  19. 1. Post card view of the bridge, c. 1910. Post ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Post card view of the bridge, c. 1910. Post card courtesy Carol Poh Miller. Photocopy by Berni Rich, Score Photographers Cleveland, OH - B & O Railroad Bridge Number 464, Spanning Old Ship Canal & Cuyahoga River, Cleveland, Cuyahoga County, OH

  20. Typical Newel Post, First Floor Newel Post, Typical Baluster, Typical ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Typical Newel Post, First Floor Newel Post, Typical Baluster, Typical Nosing, First Floor Stringer Profile, Second Floor Stringer Profile - National Home for Disabled Volunteer Soldiers - Battle Mountain Sanitarium, Treasurer's Quarters, 500 North Fifth Street, Hot Springs, Fall River County, SD

  1. 10. FLOOR 1; CENTER POST AND POSTS UNDER STONE BEAMS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. FLOOR 1; CENTER POST AND POSTS UNDER STONE BEAMS WHICH SUPPORT BRIDGE BEAMS FOR BRIDGE TREES; WEDGES FOR ADJUSTING HEIGHT OF BRIDGE TREE CAN BE SEEN - Shelter Island Windmill, Manwaring Road, Shelter Island, Suffolk County, NY

  2. 78 FR 2950 - Proposed Posting and Posting of Stockyards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-15

    ... posted the stockyards. On January 26, 2010, we published a notice in the Federal Register (75 FR 4039... posting AZ-117 Robertson Horse Sales, Benson, April 28, 2010. Arizona. CA-193 Westside Auction...

  3. Hemiparesis post cerebral malaria

    PubMed Central

    Taiaa, Oumkaltoum; Amil, Touriya; Darbi, Abdelatif

    2015-01-01

    Cerebral malaria is one of the most serious complications in the Plasmodium falciparum infection. In endemic areas, the cerebral malaria interested mainly children. The occurrence in adults is very rare and most interested adult traveling in tropical zones. This case report describes a motor deficit post cerebral malaria in a young adult traveling in malaria endemic area. This complication has been reported especially in children and seems very rare in adults. PMID:25995798

  4. Post-transplant hyperlipidaemia.

    PubMed Central

    Jindal, R. M.

    1997-01-01

    The correction of post-transplant hyperlipidaemia warrants the judicious and timely use of pharmacological agents with dietary modification and exercise. Reduction in hyperlipidaemia may have some role in decreasing the incidence of chronic rejection of allografts. The awareness that the morbidity and mortality of atherosclerotic disease may be lowered by active intervention will result in a better quality of life for transplant recipients. PMID:9497947

  5. 32 CFR 199.8 - Double coverage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 2 2013-07-01 2013-07-01 false Double coverage. 199.8 Section 199.8 National... CIVILIAN HEALTH AND MEDICAL PROGRAM OF THE UNIFORMED SERVICES (CHAMPUS) § 199.8 Double coverage. (a... insurance plans do not exceed the total charges. (b) Double coverage plan. A double coverage plan is one...

  6. 32 CFR 199.8 - Double coverage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Double coverage. 199.8 Section 199.8 National... CIVILIAN HEALTH AND MEDICAL PROGRAM OF THE UNIFORMED SERVICES (CHAMPUS) § 199.8 Double coverage. (a... insurance plans do not exceed the total charges. (b) Double coverage plan. A double coverage plan is one...

  7. 32 CFR 199.8 - Double coverage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Double coverage. 199.8 Section 199.8 National... CIVILIAN HEALTH AND MEDICAL PROGRAM OF THE UNIFORMED SERVICES (CHAMPUS) § 199.8 Double coverage. Link to an... charges. (b) Double coverage plan. A double coverage plan is one of the following: (1) Insurance plan....

  8. Anti-spacer double patterning

    NASA Astrophysics Data System (ADS)

    Hyatt, Michael; Huang, Karen; DeVilliers, Anton; Slezak, Mark; Liu, Zhi

    2014-03-01

    With extreme UV not ready for HVM for the 20nm and 14nm nodes, double patterning options that extend the use of 193nm immersion lithography beyond the optical resolution limits, such as LELE (Litho-Etch-Litho-Etch) and SADP (Self Aligned Double Patterning), are being used for critical layers for these nodes. LELE requires very stringent overlay capability of the optical exposure tool. The spacer scheme of SADP starts with a conformal film of material around the mandrels and etched along the mandrel sidewalls to form patterns with doubled frequency. SADP, while having the advantage of being a self-aligned process, adds a number of process steps and strict control of the mandrel profile is required. In this paper, we will demonstrate a novel technique - ASDP (Anti-Spacer Double Patterning), which uses only spin-on materials to achieve self-aligned double patterning. After initial resist patterning, an Anti-Spacer Generator (ASG) material is coated on the resist pattern to create the developable spacer region. Another layer of material is then coated and processed to generate the second pattern in between the first resist pattern. We were able to define 37.5nm half pitch pattern features using this technique as well as sub-resolution features for an asymmetric pattern. In this paper we will review the capability of the process in terms of CD control and LWR (line width roughness) and discuss the limitations of the process.

  9. First results from the new double velocity-double energy spectrometer VERDI

    NASA Astrophysics Data System (ADS)

    Frégeau, M. O.; Oberstedt, S.; Gamboni, Th.; Geerts, W.; Hambsch, F.-J.; Vidali, M.

    2016-05-01

    The VERDI spectrometer (VElocity foR Direct mass Identification) is a two arm time-of-flight spectrometer built at the European Commission Joint Research Centre IRMM. It determines fragment masses and kinetic energy distributions produced in nuclear fission by means of the double velocity and double energy (2v-2E) method. The simultaneous measurement of pre- and post neutron fragment characteristics allows studying the share of excitation energy between the two fragments. In particular, the evolution of fission modes and neutron multiplicity may be studied as a function of the available excitation energy. Both topics are of great importance for the development of models used in the evaluation of nuclear data, and also have important implications for the fundamental understanding of the fission process. The development of VERDI focus on maximum geometrical efficiency while striving for highest possible mass resolution. An innovative transmission start detector, using electrons ejected from the target itself, was developed. Stop signal and kinetic energy of both fragments are provided by two arrays of silicon detectors. The present design provides about 200 times higher geometrical efficiency than that of the famous COSI FAN TUTTE spectrometer [Nuclear Instruments and Methods in Physics Research 219 (1984) 569]. We report about a commissioning experiment of the VERDI spectrometer, present first results from a 2v-2E measurement of 252Cf spontaneous fission and discuss the potential of this instrument to contribute to the investigation prompt fission neutron characteristics as a function of fission fragment properties.

  10. Double ionization of atomic cadmium

    SciTech Connect

    Linusson, P.; Fritzsche, S.; Eland, J. H. D.; Hedin, L.; Karlsson, L.; Feifel, R.

    2011-02-15

    We have recorded the double photoionization spectrum of atomic Cd at four different photon energies in the range 40-200 eV. The main channel is single ionization and subsequent decay of excited Cd{sup +} states, some involving Coster-Kronig processes, whereas direct double ionization is found to be weak. The decay of the excited Cd{sup +} states shows a strong selectivity, related to the configuration of the final state. Double ionization leading to the Cd{sup 2+} ground state is investigated in some detail and is found to proceed mainly through ionization and decay of 4d correlation satellites. The most prominent autoionization peaks have been identified with the aid of quantum-mechanical calculations.

  11. New double soft emission theorems

    NASA Astrophysics Data System (ADS)

    Cachazo, Freddy; He, Song; Yuan, Ellis Ye

    2015-09-01

    We study the behavior of the tree-level S-matrix of a variety of theories as two particles become soft. By analogy with the recently found subleading soft theorems for gravitons and gluons, we explore subleading terms in double soft emissions. We first consider double soft scalar emissions and find subleading terms that are controlled by the angular momentum operator acting on hard particles. The order of the subleading theorems depends on the presence or not of color structures. Next we obtain a compact formula for the leading term in a double soft photon emission. The theories studied are a special Galileon, Dirac-Born-Infeld, Einstein-Maxwell-Scalar, nonlinear sigma model and Yang-Mills-Scalar. We use the recently found Cachazo-He-Yuan representation of these theories in order to give a simple proof of the leading order part of all these theorems.

  12. Double patterning compliant logic design

    NASA Astrophysics Data System (ADS)

    Ma, Yuangsheng; Sweis, Jason; Bencher, Chris; Deng, Yunfei; Dai, Huixiong; Yoshida, Hidekazu; Gisuthan, Bimal; Kye, Jongwook; Levinson, Harry J.

    2011-04-01

    Double patterning technology (DPT) is the only solution to enable the scaling for advanced technology nodes before EUV or any other advanced patterning techniques become available. In general, there are two major double patterning techniques: one is Litho-Etch-Litho-Etch (LELE), and the other is sidewall spacer technology, a Self-Aligned Double Patterning technique (SADP). While numerous papers have previously demonstrated these techniques on wafer process capabilities and processing costs, more study needs to be done in the context of standard cell design flow to enable their applications in mass production. In this paper, we will present the impact of DPT on logic designs, and give a thorough discussion on how to make DPT-compliant constructs, placement and routing using examples with Cadence's Encounter Digital Implementation System (EDI System).

  13. Attosecond Double-Slit Experiment

    SciTech Connect

    Lindner, F.; Schaetzel, M.G.; Baltuska, A.; Goulielmakis, E.; Walther, H.; Krausz, F.; Milosevic, D.B.; Bauer, D.; Becker, W.; Paulus, G.G.

    2005-07-22

    A new scheme for a double-slit experiment in the time domain is presented. Phase-stabilized few-cycle laser pulses open one to two windows (slits) of attosecond duration for photoionization. Fringes in the angle-resolved energy spectrum of varying visibility depending on the degree of which-way information are measured. A situation in which one and the same electron encounters a single and a double slit at the same time is observed. The investigation of the fringes makes possible interferometry on the attosecond time scale. From the number of visible fringes, for example, one derives that the slits are extended over about 500 as.

  14. Double-Chooz Neutrino Experiment

    NASA Astrophysics Data System (ADS)

    Palomares, Carmen; Double Chooz Collaboration

    2011-12-01

    The Double Chooz experiment will use the electron anti-neutrinos produced by the Chooz nuclear power station to search for a non-vanishing value of the θ13 neutrino mixing angle. Double Chooz will be the first of a new generation of neutrino experiments using identical detectors at different distances from the neutrino source to reduce the systematic errors due to the uncertainties on the neutrino flux and to the detector acceptance. The far detector will be operative by the beginning of 2011. Installation of the near detector will occur in 2012.

  15. Double stranded nucleic acid biochips

    DOEpatents

    Chernov, Boris; Golova, Julia

    2006-05-23

    This invention describes a new method of constructing double-stranded DNA (dsDNA) microarrays based on the use of pre-synthesized or natural DNA duplexes without a stem-loop structure. The complementary oligonucleotide chains are bonded together by a novel connector that includes a linker for immobilization on a matrix. A non-enzymatic method for synthesizing double-stranded nucleic acids with this novel connector enables the construction of inexpensive and robust dsDNA/dsRNA microarrays. DNA-DNA and DNA-protein interactions are investigated using the microarrays.

  16. INC424 for Patients With Myelofibrosis, Post Polycythemia Myelofibrosis or Post-essential Thrombocythemia Myelofibrosis

    ClinicalTrials.gov

    2016-05-24

    Myelofibrosis (PMF); Post Polycythemia Myelofibrosis (PPV MF); Post-essential Thrombocythemia Myelofibrosis (PET-MF); Myelofibrosis; Post Polycythemia Myelofibrosis; Post-essential Thrombocythemia Myelofibrosis

  17. POST TRAUMATIC HYPERACTIVE DELIRIUM

    PubMed Central

    Sabhesan, S.; Natarajan, M.

    1990-01-01

    SUMMMARY Hyperactive delirium following head injury is a common problem during the early recovery phase. Twenty-nine patients who evinced hyperactive delirium were prospectively followed up during; their stay In the hospital. Compared with controls, alcohol dependence was significantly more among these patients. Occurrence of delirium was related to the generalized cerebral disturbances; due to diffuse damage in acceleration injuries and due to metabolic or post-seizure disturbances in contact injuries. Follow-up of these patients showed that psychiatric problems were more common among them. PMID:21927482

  18. Post traumatic hyperactive delirium.

    PubMed

    Sabhesan, S; Natarajan, M

    1990-10-01

    Hyperactive delirium following head injury is a common problem during the early recovery phase. Twenty-nine patients who evinced hyperactive delirium were prospectively followed up during; their stay In the hospital. Compared with controls, alcohol dependence was significantly more among these patients. Occurrence of delirium was related to the generalized cerebral disturbances; due to diffuse damage in acceleration injuries and due to metabolic or post-seizure disturbances in contact injuries. Follow-up of these patients showed that psychiatric problems were more common among them. PMID:21927482

  19. Double heterojunction bipolar phototransistor model

    NASA Astrophysics Data System (ADS)

    Horak, Michal

    2003-07-01

    An analytical mathematical model of the double heterojunction NpN bipolar phototransistor with abrupt heterojunctions in three terminal configuration is presented. The thermionic-filed emission and diffusion of injected carriers is considered and the Ebers-Moll type relations for the collector and emitter current are obtained. Several steady state characteristics of the phototransistor structure are calculated (optical gain, quantum efficiency, responsivity).

  20. The double well mass filter

    DOE PAGESBeta

    Gueroult, Renaud; Rax, Jean -Marcel; Fisch, Nathaniel J.

    2014-02-03

    Various mass filter concepts based on rotating plasmas have been suggested with the specific purpose of nuclear waste remediation. We report on a new rotating mass filter combining radial separation with axial extraction. Lastly, the radial separation of the masses is the result of a “double-well” in effective radial potential in rotating plasma with a sheared rotation profile.

  1. Biphoton double-slit experiment

    SciTech Connect

    Brida, G.; Cagliero, E.; Falzetta, G.; Genovese, M.; Gramegna, M.; Predazzi, E.

    2003-09-01

    In this paper we present a double-slit experiment where two indistinguishable photons produced by type-I parametric down-conversion are each sent to a well-defined slit. Data about the diffraction and interference patterns for coincidences are presented and discussed. An analysis of these data allows a test of standard quantum mechanics against the de Broglie-Bohm theory.

  2. A Double-Minded Fractal

    ERIC Educational Resources Information Center

    Simoson, Andrew J.

    2009-01-01

    This article presents a fun activity of generating a double-minded fractal image for a linear algebra class once the idea of rotation and scaling matrices are introduced. In particular the fractal flip-flops between two words, depending on the level at which the image is viewed. (Contains 5 figures.)

  3. The double well mass filter

    SciTech Connect

    Gueroult, Renaud; Fisch, Nathaniel J.; Rax, Jean-Marcel

    2014-02-15

    Various mass filter concepts based on rotating plasmas have been suggested with the specific purpose of nuclear waste remediation. We report on a new rotating mass filter combining radial separation with axial extraction. The radial separation of the masses is the result of a “double-well” in effective radial potential in rotating plasma with a sheared rotation profile.

  4. [Post Stroke Dementia].

    PubMed

    Ihara, Masafumi

    2016-07-01

    Post-stroke dementia (PSD) is a clinical entity that encompasses all types of dementia following an index stroke. Current evidence suggests that 25-30% of ischemic stroke survivors develop immediate or delayed vascular cognitive impairment or vascular dementia. The type of stroke can be either ischemic, hemorrhagic or hypoperfusive. There are multiple risk factors for PSD including older age, family history, genetic variants, low educational status, vascular comorbidities, prior transient ischemic attack or recurrent stroke and depressive illness. Pre-stroke dementia refers to the occurrence of cognitive impairment before the index stroke, which may be caused by a vascular burden as well as insidious neurodegenerative changes. Neuroimaging determinants of dementia after stroke include silent brain infarcts, white matter changes, lacunar infarcts and medial temporal lobe atrophy. Published clinical trials have not been promising and there is little information on whether PSD can be prevented using pharmacological agents. Control of vascular disease risk and prevention of recurrent strokes are key to reducing the burden of cognitive decline and post-stroke dementia. Modern imaging and analysis techniques will help to elucidate the mechanism of PSD and establish better treatment. PMID:27395459

  5. Keepers of the double stars

    NASA Astrophysics Data System (ADS)

    Tenn, Joseph S.

    2013-03-01

    Astronomers have long tracked double stars in efforts to find those that are gravitationally-bound binaries and then to determine their orbits. Early catalogues by the Herschels, Struves, and others began with their own discoveries. In 1906 court reporter and amateur astronomer Sherburne Wesley Burnham published a massive double star catalogue containing data from many observers on more than 13,000 systems. Lick Observatory astronomer Robert Grant Aitken produced a much larger catalogue in 1932 and coordinated with Robert Innes of Johannesburg, who catalogued the southern systems. Aitken maintained and expanded Burnham's records of observations on handwritten file cards, and eventually turned them over to the Lick Observatory, where astrometrist Hamilton Jeffers further expanded the collection and put all the observations on punched cards. With the aid of Frances M. "Rete" Greeby he made two catalogues: an Index Catalogue with basic data about each star, and a complete catalogue of observations, with one observation per punched card. He enlisted Willem van den Bos of Johannesburg to add southern stars, and together they published the Index Catalogue of Visual Double Stars, 1961.0. As Jeffers approached retirement he became greatly concerned about the disposition of the catalogues. He wanted to be replaced by another "double star man," but Lick Director Albert E. Whitford had the new 120-inch reflector, the world's second largest telescope, and he wanted to pursue modern astrophysics instead. Jeffers was vociferously opposed to turning over the card files to another institution, and especially against their coming under the control of Kaj Strand of the United States Naval Observatory. In the end the USNO got the files and has maintained the records ever since, first under Charles Worley, and, since 1997, under Brian Mason. Now called the Washington Double Star Catalog (WDS), it is completely online and currently contains more than 1,200,000 measures of more than 125

  6. A laboratory investigation of potential double layers

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1987-01-01

    In a triple plasma device, the injection of electron current from the source chamber to the target chamber causes the formation of a potential double layer. At a low current density, the space charge of the injected current produces a virtual cathode-type potential double layer. This double layer is stable, and various wave instabilities are observed to associate with this double layer. As the current density is increased, the double layer becomes unstable, and a moving double layer results. As the current density is increased further, the enhanced ionization causes the neutralization of the space charge of the electron beam, and the beam plasma discharge is ignited.

  7. A laboratory investigation of potential double layers

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1987-01-01

    In a triple plasma device, the injection of electron current from the source chamber to the target chamber causes the formation of a potential double layer. At a low current density, the space charge of the injected current produces a virtual cathode-type potential double layer. This double layer is stable and various wave instabilities are observed to associate with this double layer. As the current density is increased, the double layer becomes unstable and a moving double layer results. As the current density is increased further, the enhanced ionization causes the neutralization of the space charge of the electron beam and the 'beam plasma discharge' is ignited.

  8. Double Photoionization into Double Core-Hole States in Xe

    SciTech Connect

    Hikosaka, Y.; Kaneyasu, T.; Shigemasa, E.; Lablanquie, P.; Penent, F.; Eland, J. H. D.; Aoto, T.; Ito, K.

    2007-05-04

    Double photoionization (DPI) leading to double core-hole states of Xe{sup 2+} 4d{sup -2} has been studied using a magnetic bottle time-of-flight spectrometer. The assignments of the Xe{sup 2+} 4d{sup -2} states are confirmed by the Auger lines extracted from fourfold coincidences including two photoelectrons and two Auger electrons. It is estimated that the core-core DPI into Xe{sup 2+} 4d{sup -2} at a photon energy of 301.6 eV has a favored cross section of about 0.3 MB. The intense core-core DPI is due to mixing of the 4d{sup -2} continuum with the 4p single photoionization, which is manifested in the relative intensities of the Xe{sup 2+} 4d{sup -2} components.

  9. Double photoionization into double core-hole states in Xe.

    PubMed

    Hikosaka, Y; Lablanquie, P; Penent, F; Kaneyasu, T; Shigemasa, E; Eland, J H D; Aoto, T; Ito, K

    2007-05-01

    Double photoionization (DPI) leading to double core-hole states of Xe2+ 4d(-2) has been studied using a magnetic bottle time-of-flight spectrometer. The assignments of the Xe2+ 4d(-2) states are confirmed by the Auger lines extracted from fourfold coincidences including two photoelectrons and two Auger electrons. It is estimated that the core-core DPI into Xe2+ 4d(-2) at a photon energy of 301.6 eV has a favored cross section of about 0.3 MB. The intense core-core DPI is due to mixing of the 4d(-2) continuum with the 4p single photoionization, which is manifested in the relative intensities of the Xe2+ 4d(-2) components. PMID:17501570

  10. Post retention and post/core shear bond strength of four post systems.

    PubMed

    Stockton, L W; Williams, P T; Clarke, C T

    2000-01-01

    As clinicians we continue to search for a post system which will give us maximum retention while maximizing resistance to root fracture. The introduction of several new post systems, with claims of high retentive and resistance to root fracture values, require that independent studies be performed to evaluate these claims. This study tested the tensile and shear dislodgment forces of four post designs that were luted into roots 10 mm apical of the CEJ. The Para Post Plus (P1) is a parallel-sided, passive design; the Para Post XT (P2) is a combination active/passive design; the Flexi-Post (F1) and the Flexi-Flange (F2) are active post designs. All systems tested were stainless steel. This study compared the test results of the four post designs for tensile and shear dislodgment. All mounted samples were loaded in tension until failure occurred. The tensile load was applied parallel to the long axis of the root, while the shear load was applied at 450 to the long axis of the root. The Flexi-Post (F1) was significantly different from the other three in the tensile test, however, the Para Post XT (P2) was significantly different to the other three in the shear test and had a better probability for survival in the Kaplan-Meier survival function test. Based on the results of this study, our recommendation is for the Para Post XT (P2). PMID:11203854