WorldWideScience

Sample records for repeater sgr 1627-41

  1. RXTE All-Sky Monitor Localization of SGR 1627-41

    OpenAIRE

    Smith, Donald A.; Bradt, Hale V.; Levine, Alan M.

    1999-01-01

    The fourth unambiguously identified Soft Gamma Repeater (SGR), SGR1627-41, was discovered with the BATSE instrument on 1998 June 15 (Kouveliotou et al. 1998). Interplanetary Network (IPN) measurements and BATSE data constrained the location of this new SGR to a 6 deg segment of a narrow (19") annulus (Hurley et al. 1999; Woods et al. 1998). We present two bursts from this source observed by the All-Sky Monitor (ASM) on RXTE. We use the ASM data to further constrain the source location to a 5'...

  2. RXTE All-Sky Monitor Localization of SGR 1627-41

    Science.gov (United States)

    Smith, D. A.; Bradt, H. V.; Levine, A. M.

    1999-09-01

    The fourth unambiguously identified Soft Gamma Repeater (SGR), SGR 1627--41, was discovered with the BATSE instrument on 1998 June 15 (Kouveliotou et al. 1998). Interplanetary Network (IPN) measurements and BATSE data constrained the location of this new SGR to a 6(deg) segment of a narrow (19('') ) annulus (Hurley et al. 1999; Woods et al. 1998). We report on two bursts from this source observed by the All-Sky Monitor (ASM) on RXTE. We use the ASM data to further constrain the source location to a 5(') long segment of the BATSE/IPN error box. The ASM/IPN error box lies within 0.3(') of the supernova remnant (SNR) G337.0--0.1. The probability that a SNR would fall so close to the error box purely by chance is ~ 5%.

  3. Rossi X-Ray Timing Explorer All-Sky Monitor Localization of SGR 1627-41

    Science.gov (United States)

    Smith, Donald A.; Bradt, Hale V.; Levine, Alan M.

    1999-07-01

    The fourth unambiguously identified soft gamma repeater (SGR), SGR 1627-41, was discovered with the BATSE instrument on 1998 June 15. Interplanetary Network (IPN) measurements and BATSE data constrained the location of this new SGR to a 6° segment of a narrow (19") annulus. We present two bursts from this source observed by the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer. We use the ASM data to further constrain the source location to a 5' long segment of the BATSE/IPN error box. The ASM/IPN error box lies within 0.3 arcmin of the supernova remnant G337.0-0.1. The probability that a supernova remnant would fall so close to the error box purely by chance is ~5%.

  4. SROSS C-2 Detections of Gamma Ray Bursts and the SGR 1627-41 ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    512 ms. The pre-trigger data are obtained using a circulating memory. A maximum of ... background. This is done by removing the BURST portion in the GRB time history, since quite often the real burst is of very short duration. The GRB duration (T90) is calculated using an .... the statistical noise in the data. 4.7 Unconfirmed ...

  5. DISCOVERY OF A NEW SOFT GAMMA REPEATER: SGR J0418 + 5729

    International Nuclear Information System (INIS)

    Van der Horst, A. J.; Connaughton, V.; Briggs, M. S.; Kouveliotou, C.; Goegues, E.; Kaneko, Y.; Wachter, S.; Granot, J.; Ramirez-Ruiz, E.; Woods, P. M.; Aptekar, R. L.; Frederiks, D. D.; Golenetskii, S.; Barthelmy, S. D.; Cummings, J. R.; Gehrels, N.; Finger, M. H.; Gelino, C. R.; Gelino, D. M.; Hurley, K.

    2010-01-01

    On 2009 June 5, the Gamma-ray Burst Monitor (GBM) onboard the Fermi Gamma-ray Space Telescope triggered on two short and relatively dim bursts with spectral properties similar to soft gamma repeater (SGR) bursts. Independent localizations of the bursts by triangulation with the Konus-RF and with the Swift satellite confirmed their origin from the same, previously unknown, source. The subsequent discovery of X-ray pulsations with the Rossi X-ray Timing Explorer confirmed the magnetar nature of the new source, SGR J0418 + 5729. We describe here the Fermi/GBM observations, the discovery and the localization of this new SGR, and our infrared and Chandra X-ray observations. We also present a detailed temporal and spectral study of the two GBM bursts. SGR J0418 + 5729 is the second source discovered in the same region of the sky in the last year, the other one being SGR J0501 + 4516. Both sources lie in the direction of the galactic anti-center and presumably at the nearby distance of ∼2 kpc (assuming they reside in the Perseus arm of our Galaxy). The near-threshold GBM detection of bursts from SGR J0418 + 5729 suggests that there may be more such 'dim' SGRs throughout our Galaxy, possibly exceeding the population of 'bright' SGRs. Finally, using sample statistics, we conclude that the number of observable active magnetars in our Galaxy at any given time is ∼<10, in agreement with our earlier estimates.

  6. Hard burst emission from the soft gamma repeater SGR 1900+14

    NARCIS (Netherlands)

    Woods, P.M.; Kouveliotou, C.; van Paradijs, J.; Briggs, M.S.; Hurley, K.; Göğüş, E.; Preece, R.D.; Giblin, T.W.; Thompson, C.; Duncan, R.C.

    1999-01-01

    We present evidence for burst emission from SGR 1900+14 with a power-law high-energy spectrum extending beyond 500 keV. Unlike previous detections of high-energy photons during bursts from soft gamma repeaters (SGRs), these emissions are not associated with extraordinarily bright flares. Not only is

  7. Quiet but still bright: XMM-Newton observations of the soft gamma-ray repeater SGR 0526-66

    NARCIS (Netherlands)

    Tiengo, A.; Esposito, P.; Mereghetti, S.; Israel, G.L.; Stella, L.; Turolla, R.; Zane, S.; Rea, N.; Götz, D.; Feroci, M.

    2009-01-01

    SGR 0526-66 was the first soft gamma-ray repeater (SGR) from which a giant flare was detected in March 1979, suggesting the existence of magnetars, i.e. neutron stars powered by the decay of their extremely strong magnetic field. Since then, very little information has been obtained on this object,

  8. SGR-like behaviour of the repeating FRB 121102

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F.Y.; Yu, H., E-mail: fayinwang@nju.edu.cn, E-mail: yuhai@smail.nju.edu.cn [School of Astronomy and Space Science, Nanjing University, 163 Xianlin Avenue, Nanjing, 210093 China (China)

    2017-03-01

    Fast radio bursts (FRBs) are millisecond-duration radio signals occurring at cosmological distances. However the physical model of FRBs is mystery, many models have been proposed. Here we study the frequency distributions of peak flux, fluence, duration and waiting time for the repeating FRB 121102. The cumulative distributions of peak flux, fluence and duration show power-law forms. The waiting time distribution also shows power-law distribution, and is consistent with a non-stationary Poisson process. These distributions are similar as those of soft gamma repeaters (SGRs). We also use the statistical results to test the proposed models for FRBs. These distributions are consistent with the predictions from avalanche models of slowly driven nonlinear dissipative systems.

  9. Quiet but still bright: XMM-Newton observations of the soft gamma-ray repeater SGR 0526-66

    International Nuclear Information System (INIS)

    Tiengo, A.; Esposito, P.; Mereghetti, S.; Esposito, P.; Israel, G.L.; Stella, L.; Turolla, R.; Turolla, R.; Zane, S.; Rea, N.; Gotz, D.; Feroci, M.

    2009-01-01

    SGR 0526-66 was the first soft gamma-ray repeater from which a giant flare was detected in 1979 March, suggesting the existence of magnetars, i.e. neutron stars powered by the decay of their extremely strong magnetic field. Since then, very little information has been obtained on this object, mainly because it has been burst inactive since 1983 and the study of its persistent X-ray emission has been hampered by its large distance and its location in a X-ray bright supernova remnant in the Large Magellanic Cloud. Here, we report on a comprehensive analysis of all the available XMM-Newton observations of SGR 0526-66. In particular, thanks to a deep observation taken in 2007, we measured its pulsation period (P = 8.0544 ± 0.0002 s) 6 years after its latest detection by Chandra. This allowed us to detect for the first time a significant reduction of its spin-down rate. From a comparison with two shorter XMM-Newton observations performed in 2000 and 2001, we found no significant changes in the spectrum, which is well modelled by an absorbed power law with nH = 4.6E+21 cm -2 and photon index = 3.27. The high luminosity about 4E+35 erg/s, in the 1-10 keV energy band) still observed about 25 years after the latest detection of bursting activity places SGR 0526-66 in the group of bright and persistent magnetar candidates. (authors)

  10. Two years of INTEGRAL monitoring of the soft gamma-ray repeater SGR 1806-20: from quiescence to frenzy

    DEFF Research Database (Denmark)

    Gotz, D.; Mereghetti, S.; Molkov, S.

    2006-01-01

    SGR 1806-20 has been observed for more than 2 years with the INTEGRAL satellite. In this period the source went from a quiescent state into a very active one culminating in a giant flare on December 27, 2004. Here we report on the properties of all the short bursts detected with INTEGRAL before t...

  11. An X-ray Pulsar with a Superstrong Magnetic Field in the Soft Gamma-Ray Repeater SGR1806-20

    Science.gov (United States)

    Kouveliotou, C.; Dieters, S.; Strohmayer, T.; vanParadijs, J.; Fishman, G. J.; Meegan, C. A.; Hurley, K.; Kommers, J.; Smith, I.; Frail, D.; hide

    1998-01-01

    Soft gamma-ray repeaters (SGRs) emit multiple, brief (approximately O.1 s) intense outbursts of low-energy gamma-rays. They are extremely rare; three are known in our galaxy and one in the Large Magellanic Cloud. Two SGRs are associated with young supernova remnants (SNRs), and therefore most probably with neutron stars, but it remains a puzzle why SGRs are so different from 'normal' radio pulsars. Here we report the discovery of pulsations in the persistent X-ray flux of SGR1806-20, with a period of 7.47 s and a spindown rate of 2.6 x 10(exp -3) s/yr. We argue that the spindown is due to magnetic dipole emission and find that the pulsar age and (dipolar) magnetic field strength are approximately 1500 years and 8 x 10(exp 14) gauss, respectively. Our observations demonstrate the existence of 'magnetars', neutron stars with magnetic fields about 100 times stronger than those of radio pulsars, and support earlier suggestions that SGR bursts are caused by neutron-star 'crust-quakes' produced by magnetic stresses. The 'magnetar' birth rate is about one per millenium, a substantial fraction of that of radio pulsars. Thus our results may explain why some SNRs have no radio pulsars.

  12. V2282 Sgr Revisited

    Directory of Open Access Journals (Sweden)

    Roberto Nesci

    2014-12-01

    Full Text Available The nature of V2282 Sgr is examined on the basis of several multiband observations: a 20 years long I-band light curve of V2282 Sgr obtained from archive photographic plates of the Asiago and Catania Observatories; a CCD R-band light curve obtained at Cornero Observatory; JHK photometry from 2MASS and UKDISS; Spitzer IRAC and MIPS images; optical spectra from Loiano Observatory; X-ray flux from CHANDRA. The star has a K-type spectrum with strong emission lines and is irregularly variable at all wavebands. The overall evidences suggest that V2282 Sgr is a Pre Main Sequence star with an accretion disk.

  13. Background Information: Magnetars, Soft Gamma-Ray Repeaters and the Most Powerful Magnetic Fields in the Universe

    Science.gov (United States)

    1998-08-01

    nebula shining in the light of particles accelerated to nearly the speed of light by the same event that gave rise to the bright gamma-ray bursts. Figure Caption: Two views toward SGR 1900+14. These radio images, taken with the Very Large Array, were made on 1998 June 25 (left) and September 3 (right). The position of the quiescent X-ray source RX J190717+0919.3, thought to indicate the approximate location of SGR 1900+14, is indicated by the circle. The radio source turned on shortly after the bright gamma-ray burst of August 27th and then rapidly faded from view a week later. SGR 1627-41: The Newest SGR SGR 1627-41 is the newest member of the SGR family. See the NASA press release announcing this exciting discovery. While its position is not well-determined yet, there is only one known supernova remnant in the region: G337.0-0.1. It is a compact supernova remnant 35,000 light years from the Sun which lies in the CTB 33 complex (see below), a young region with plenty of active star formation going on.

  14. Stellar orbits around Sgr A*

    International Nuclear Information System (INIS)

    Trippe, S; Gillessen, S; Ott, T; Eisenhauer, F; Paumard, T; Martins, F; Genzel, R; Schoedel, R; Eckart, A; Alexander, T

    2006-01-01

    In this article we present and discuss the latest results from the observations of stars (''S-stars'') orbiting Sgr A* . With improving data quality the number of observed S-stars has increased substantially in the last years. The combination of radial velocity and proper motion information allows an ever more precise determination of orbital parameters and of the mass of and the distance to the supermassive black hole in the centre of the Milky Way. Additionally, the orbital solutions allow us to verify an agreement between the NIR source Sgr A* and the dynamical centre of the stellar orbits to within 2 mas

  15. Large Torque Variations in Two Soft Gamma Repeaters

    NARCIS (Netherlands)

    Woods, P.M.; Kouveliotou, C.; Göğüş, E.; Finger, M.H.; Swank, J.; Markwardt, C.B.; Hurley, K.; van der Klis, M.

    2002-01-01

    We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-Ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor

  16. The SSS classical nova V5116 Sgr

    Science.gov (United States)

    Sala, G.; Ness, J.; Greiner, J.; Hernanz, M.

    2017-10-01

    XMM-Newton observed the nova V5116 Sgr during its supersoft phase (SSS). V5116 Sgr showed a decrease of the flux by a factor around 8 during 2/3 of the orbital period. The broad band EPIC spectra remain unchanged during the different flux phases, suggesting an occultation of the central source in a high inclination system. While the global SED does not change significantly, the RGS spectrum is changing between the high and the low flux phases. The non-occultation phase shows a typical white dwarf atmosphere spectrum, dominated by absorption lines. During the low flux periods an extra component of emission lines is superimposed to the soft X-ray continuum. This supports the picture of V5116 Sgr as the clearest example of a system switching between the SSa class of SSS novae, with spectra dominated by absorption lines, and the SSe class, showing an emission lines component. In addition, the simultaneous OM images allow us to find a phase solution for the X-ray light-curve. A thick rim of the accretion disk as the one developed for the SSSs CAL 87, RX J0019.8, and RX J0513.9 could provide a plausible model both for the optical and the X-ray light curve of V5116 Sgr.

  17. The Submillimeter Polarization of Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Marrone, Daniel P [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Moran, James M [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Rao, Ramprasad [Inst. of Ast. and Astrophys., Academia Sinica, PO Box 23-141, Taipei 10617, Taiwan (China)

    2006-12-15

    We report on the submillimeter properties of Sgr A* derived from observations with the Submillimeter Array and its polarimeter. We ftid that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured simultaneously, indicating a transition to optically thin emission around 300-400 GHz. We also present very sensitive and well calibrated measurements of the polarization of Sgr A* at 230 and 345 GHz. With these data we are able to show for the frst time that the polarization of Sgr A* varies on hour timescales, as has been observed for the total intensity. On one night we fhd variability that may arise from a polarized 'blob' orbiting the black hole. Finally, we use the ensemble of observations to determine the rotation measure. This represents the frst statistically significant rotation measure determination and the only one made without resorting to comparing position angles measured at separate epochs. We frid a rotation measure of (-5.6 {+-} 0.7) x 10{sup 5} rad m{sup 2}, with no evidence for variability on inter-day timescales at the level of the measurement error. The stability constrains interday flictuations in the accretion rate to 8%. The mean intrinsic polarization position angle is 167{sup 0}{+-}7{sup 0} and we detect variations of 31{sup +18}{sub -9} degrees. This separation of intrinsic polarization changes and possible rotation measure flictuations is now possible because of the frequency coverage and sensitivity of our data. The observable rotation measure restricts the accretion rate to the range 2 x 10{sup -7} M o-dot yr{sup -1} to 2 x 10{sup -9} M o-dot yr{sup -1}, if the magnetic field is near equipartition and ordered.

  18. The Submillimeter Polarization of Sgr A*

    International Nuclear Information System (INIS)

    Marrone, Daniel P; Moran, James M; Zhao, Jun-Hui; Rao, Ramprasad

    2006-01-01

    We report on the submillimeter properties of Sgr A* derived from observations with the Submillimeter Array and its polarimeter. We ftid that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured simultaneously, indicating a transition to optically thin emission around 300-400 GHz. We also present very sensitive and well calibrated measurements of the polarization of Sgr A* at 230 and 345 GHz. With these data we are able to show for the frst time that the polarization of Sgr A* varies on hour timescales, as has been observed for the total intensity. On one night we fhd variability that may arise from a polarized 'blob' orbiting the black hole. Finally, we use the ensemble of observations to determine the rotation measure. This represents the frst statistically significant rotation measure determination and the only one made without resorting to comparing position angles measured at separate epochs. We frid a rotation measure of (-5.6 ± 0.7) x 10 5 rad m 2 , with no evidence for variability on inter-day timescales at the level of the measurement error. The stability constrains interday flictuations in the accretion rate to 8%. The mean intrinsic polarization position angle is 167 0 ±7 0 and we detect variations of 31 +18 -9 degrees. This separation of intrinsic polarization changes and possible rotation measure flictuations is now possible because of the frequency coverage and sensitivity of our data. The observable rotation measure restricts the accretion rate to the range 2 x 10 -7 M o-dot yr -1 to 2 x 10 -9 M o-dot yr -1 , if the magnetic field is near equipartition and ordered

  19. The Submillimeter Polarization of Sgr A*

    Science.gov (United States)

    Marrone, Daniel P.; Moran, James M.; Zhao, Jun-Hui; Rao, Ramprasad

    2006-12-01

    We report on the submillimeter properties of Sgr A* derived from observations with the Submillimeter Array and its polarimeter. We ftid that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured simultaneously, indicating a transition to optically thin emission around 300 400 GHz. We also present very sensitive and well calibrated measurements of the polarization of Sgr A* at 230 and 345 GHz. With these data we are able to show for the frst time that the polarization of Sgr A* varies on hour timescales, as has been observed for the total intensity. On one night we fhd variability that may arise from a polarized "blob" orbiting the black hole. Finally, we use the ensemble of observations to determine the rotation measure. This represents the frst statistically significant rotation measure determination and the only one made without resorting to comparing position angles measured at separate epochs. We frid a rotation measure of (-5.6 ± 0.7) × 105 rad m2, with no evidence for variability on inter-day timescales at the level of the measurement error. The stability constrains interday flictuations in the accretion rate to 8%. The mean intrinsic polarization position angle is 167°±7° and we detect variations of 31+18-9 degrees. This separation of intrinsic polarization changes and possible rotation measure flictuations is now possible because of the frequency coverage and sensitivity of our data. The observable rotation measure restricts the accretion rate to the range 2 × 10-7 Mdot o yr-1 to 2 × 10-9 Mdot o yr-1, if the magnetic ffeld is near equipartition and ordered.

  20. Bipartisan proposal calls for SGR repeal

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-11-01

    Full Text Available No abstract available. Article truncated at 150 words. The Washington Post (11/1, Carey reports a bipartisan group of legislators has agreed on a framework replacing the “problematic” Medicare payment formula in an attempt to end the annual Sustainable Growth Rate (SGR or “doc fix” debate. The current system is set to reduce Medicare physician payments by approximately 25% on Jan. 1 without Congressional intervention. Senate Finance Committee Chairman Max Baucus (D-MT and House Ways and Means Committee Chairman Dave Camp (R-MI introduced a draft proposal that would “encourage care management services for individuals with complex chronic care needs through the development of new payment codes for such services, as well as leverage physician-developed standard of care guidelines to avoid the unnecessary provision of services”. The Committees value your feedback on this proposal. Please submit written comments to the Finance SGR comments mailbox at sgrcomments@finance.senate.gov and the Ways & Means SGR comments mailbox at sgrwhitepaper@mail.house.gov by Tuesday, November 12, …

  1. Sgr A* Emission Parametrizations from GRMHD Simulations

    Science.gov (United States)

    Anantua, Richard; Ressler, Sean; Quataert, Eliot

    2018-06-01

    Galactic Center emission near the vicinity of the central black hole, Sagittarius (Sgr) A*, is modeled using parametrizations involving the electron temperature, which is found from general relativistic magnetohydrodynamic (GRMHD) simulations to be highest in the disk-outflow corona. Jet-motivated prescriptions generalizing equipartition of particle and magnetic energies, e.g., by scaling relativistic electron energy density to powers of the magnetic field strength, are also introduced. GRMHD jet (or outflow)/accretion disk/black hole (JAB) simulation postprocessing codes IBOTHROS and GRMONTY are employed in the calculation of images and spectra. Various parametric models reproduce spectral and morphological features, such as the sub-mm spectral bump in electron temperature models and asymmetric photon rings in equipartition-based models. The Event Horizon Telescope (EHT) will provide unprecedentedly high-resolution 230+ GHz observations of the "shadow" around Sgr A*'s supermassive black hole, which the synthetic models presented here will reverse-engineer. Both electron temperature and equipartition-based models can be constructed to be compatible with EHT size constraints for the emitting region of Sgr A*. This program sets the groundwork for devising a unified emission parametrization flexible enough to model disk, corona and outflow/jet regions with a small set of parameters including electron heating fraction and plasma beta.

  2. Studying MHD and radiative processes in Sgr A*

    NARCIS (Netherlands)

    Dibi, S.

    2014-01-01

    This thesis details four different studies of accretion and emission processes around the Galactic Center Sgr A*. We are studying Sgr A* in particular because it is the closest supermassive black hole and therefore we have incomparable observational data to test our theories and predictions.

  3. On the enhanced X-ray emission from SGR 1900+14 after the August 27th giant flare

    International Nuclear Information System (INIS)

    Ertan, Ue.; Alpar, M.A.

    2004-01-01

    We show that the giant flares of soft gamma ray repeaters (E∼10 44 erg) can push the inner regions of a fall-back disk out to larger radii by radiation pressure, while matter remains bound to the system for plausible parameters. The subsequent relaxation of this pushed-back matter can account for the observed enhanced X-ray emission after the August 27 th giant flare of SGR 1900+14

  4. Strong gravitational lensing by Sgr A*

    International Nuclear Information System (INIS)

    Bin-Nun, Amitai Y

    2011-01-01

    In recent years, there has been increasing recognition of the potential to use the galactic center as a probe of general relativity in the strong field. There is almost certainly a black hole at Sgr A* in the galactic center, and this would allow us to have the opportunity to probe dynamics near the exterior of the black hole. In the last decade, there has been theoretical research into extreme gravitational lensing in the galactic center. Unlike in most applications of gravitational lensing, where the bending angle is of the order of, at most, an arc minute, very large bending angles are possible for light that closely approaches a black hole. Photons may even loop multiple times around a black hole before reaching the observer. There have been many proposals to use light's close approach to the black hole as a probe of the black hole metric. Of particular interest are the properties of images formed from the light of S stars orbiting in the galactic center. This paper will review some of the attempts made to study extreme lensing as well as extend the analysis of S star lensing. In particular, we are interested in the effect of a Reissner-Nordstrom like 1/r 2 term in the metric and how this would affect the properties of relativistic images.

  5. Search for soft gamma repeaters in the SMM/HXRBS data

    Science.gov (United States)

    Kouveliotou, C.; Norris, J. P.; Wood, K. S.; Cline, T. L.; Dennis, B. R.; Desal, U. D.; Orwig, L. E.

    1992-01-01

    The triggered fast memory of the hard X-ray burst spectrometer (HXRBS) on board the SMM is used to describe the results of a search for short transients resembling soft gamma repeater (SGR) bursts. Memory data for a total of about 4000 burst triggers, out of which only a very few could be considered as valid SGR candidate events, are analyzed. The search methodology is outlined, the HXRBS exposure and sensitivity to SGR bursts are calculated, and the criteria which constrain the number of candidate events are described. An upper limit is given for the SGR source number density. This limit, combined with results from other relevant observations and the assumption of a neutron star origin, are applied to obtain a constraint on SGR-active lifetimes.

  6. Variable accretion of stellar winds onto Sgr A*

    Science.gov (United States)

    Cuadra, Jorge; Nayakshin, Sergei

    2006-12-01

    We report a 3-dimensional numerical study of the accretion of stellar winds onto Sgr A*, the super-massive black hole at the centre of our Galaxy. Compared with previous investigations, we allow the stars to be on realistic orbits, include the recently discovered slow wind sources, and allow for optically thin radiative cooling. We frst show the strong inflience of the stellar dynamics on the accretion onto the central black hole. We then present more realistic simulations of Sgr A* accretion and frid that the slow winds shock and rapidly cool, forming cold gas clumps and flaments that coexist with the hot X-ray emitting gas. The accretion rate in this case is highly variable on time-scales of tens to hundreds of years. Such variability can in principle lead to a strongly non-linear response through accretion fbw physics not resolved here, making Sgr A* an important energy source for the Galactic centre.

  7. Variable accretion of stellar winds onto Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Cuadra, Jorge [Max-Planck-Institut fuer Astrophysik, D-85741 Garching (Germany); Nayakshin, Sergei [Department of Physics and Astronomy, University of Leicester, LEI 7RH (United Kingdom)

    2006-12-15

    We report a 3-dimensional numerical study of the accretion of stellar winds onto Sgr A*, the super-massive black hole at the centre of our Galaxy. Compared with previous investigations, we allow the stars to be on realistic orbits, include the recently discovered slow wind sources, and allow for optically thin radiative cooling. We frst show the strong inflience of the stellar dynamics on the accretion onto the central black hole. We then present more realistic simulations of Sgr A* accretion and frid that the slow winds shock and rapidly cool, forming cold gas clumps and flaments that coexist with the hot X-ray emitting gas. The accretion rate in this case is highly variable on time-scales of tens to hundreds of years. Such variability can in principle lead to a strongly non-linear response through accretion fbw physics not resolved here, making Sgr A* an important energy source for the Galactic centre.

  8. Variable accretion of stellar winds onto Sgr A*

    International Nuclear Information System (INIS)

    Cuadra, Jorge; Nayakshin, Sergei

    2006-01-01

    We report a 3-dimensional numerical study of the accretion of stellar winds onto Sgr A*, the super-massive black hole at the centre of our Galaxy. Compared with previous investigations, we allow the stars to be on realistic orbits, include the recently discovered slow wind sources, and allow for optically thin radiative cooling. We frst show the strong inflience of the stellar dynamics on the accretion onto the central black hole. We then present more realistic simulations of Sgr A* accretion and frid that the slow winds shock and rapidly cool, forming cold gas clumps and flaments that coexist with the hot X-ray emitting gas. The accretion rate in this case is highly variable on time-scales of tens to hundreds of years. Such variability can in principle lead to a strongly non-linear response through accretion fbw physics not resolved here, making Sgr A* an important energy source for the Galactic centre

  9. An Expanding Radio Nebula Produced by a Giant Flare from the Magnetar SGR 1806-20

    Energy Technology Data Exchange (ETDEWEB)

    Gaensler, B.

    2005-03-04

    Soft gamma repeaters (SGRs) are ''magnetars'', a small class of slowly spinning neutron stars with extreme surface magnetic fields, B {approx} 10{sup 15} gauss. On 2004 December 27, a giant flare was detected from the magnetar SGR 1806-20, the third such event ever recorded. This burst of energy was detected by a variety of instruments and even caused an ionospheric disturbance in the Earth's upper atmosphere recorded around the globe. Here we report the detection of a fading radio afterglow produced by this outburst, with a luminosity 500 times larger than the only other detection of a similar source. From day 6 to day 19 after the flare from SGR 1806-20, a resolved, linearly polarized, radio nebula was seen, expanding at approximately a quarter the speed of light. To create this nebula, at least 4 x 10{sup 43} ergs of energy must have been emitted by the giant flare in the form of magnetic fields and relativistic particles. The combination of spatially resolved structure and rapid time evolution allows a study in unprecedented detail of a nearby analog to supernovae and gamma-ray bursts.

  10. An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20.

    Science.gov (United States)

    Gaensler, B M; Kouveliotou, C; Gelfand, J D; Taylor, G B; Eichler, D; Wijers, R A M J; Granot, J; Ramirez-Ruiz, E; Lyubarsky, Y E; Hunstead, R W; Campbell-Wilson, D; van der Horst, A J; McLaughlin, M A; Fender, R P; Garrett, M A; Newton-McGee, K J; Palmer, D M; Gehrels, N; Woods, P M

    2005-04-28

    Soft gamma-ray repeaters (SGRs) are 'magnetars', a small class of slowly spinning neutron stars with extreme surface magnetic fields, B approximately 10(15) gauss (refs 1 , 2 -3). On 27 December 2004, a giant flare was detected from the magnetar SGR 1806-20 (ref. 2), only the third such event recorded. This burst of energy was detected by a variety of instruments and even caused an ionospheric disturbance in the Earth's upper atmosphere that was recorded around the globe. Here we report the detection of a fading radio afterglow produced by this outburst, with a luminosity 500 times larger than the only other detection of a similar source. From day 6 to day 19 after the flare from SGR 1806-20, a resolved, linearly polarized, radio nebula was seen, expanding at approximately a quarter of the speed of light. To create this nebula, at least 4 x 10(43) ergs of energy must have been emitted by the giant flare in the form of magnetic fields and relativistic particles.

  11. STACKED SEARCH FOR GRAVITATIONAL WAVES FROM THE 2006 SGR 1900+14 STORM

    International Nuclear Information System (INIS)

    Abbott, B. P.; Abbott, R.; Adhikari, R.; Anderson, S. B.; Araya, M.; Armandula, H.; Aso, Y.; Ballmer, S.; Ajith, P.; Allen, B.; Aulbert, C.; Allen, G.; Amin, R. S.; Anderson, W. G.; Armor, P.; Arain, M. A.; Aston, S.; Aufmuth, P.; Babak, S.; Baker, P.

    2009-01-01

    We present the results of a LIGO search for short-duration gravitational waves (GWs) associated with the 2006 March 29 SGR 1900+14 storm. A new search method is used, 'stacking' the GW data around the times of individual soft-gamma bursts in the storm to enhance sensitivity for models in which multiple bursts are accompanied by GW emission. We assume that variation in the time difference between burst electromagnetic emission and potential burst GW emission is small relative to the GW signal duration, and we time-align GW excess power time-frequency tilings containing individual burst triggers to their corresponding electromagnetic emissions. We use two GW emission models in our search: a fluence-weighted model and a flat (unweighted) model for the most electromagnetically energetic bursts. We find no evidence of GWs associated with either model. Model-dependent GW strain, isotropic GW emission energy E GW , and γ ≡ E GW /E EM upper limits are estimated using a variety of assumed waveforms. The stacking method allows us to set the most stringent model-dependent limits on transient GW strain published to date. We find E GW upper limit estimates (at a nominal distance of 10 kpc) of between 2 x 10 45 erg and 6 x 10 50 erg depending on the waveform type. These limits are an order of magnitude lower than upper limits published previously for this storm and overlap with the range of electromagnetic energies emitted in soft gamma repeater (SGR) giant flares.

  12. Sgr A* flares: tidal disruption of asteroids and planets?

    NARCIS (Netherlands)

    Zubovas, K.; Nayakshin, S.; Markoff, S.

    2012-01-01

    It is theoretically expected that a supermassive black hole (SMBH) in the centre of a typical nearby galaxy disrupts a solar-type star every ∼105 yr, resulting in a bright flare lasting for months. Sgr A*, the resident SMBH of the Milky Way, produces (by comparison) tiny flares that last only hours

  13. POSSIBLE ORIGIN OF THE G2 CLOUD FROM THE TIDAL DISRUPTION OF A KNOWN GIANT STAR BY SGR A*

    International Nuclear Information System (INIS)

    Guillochon, James; Loeb, Abraham; MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2014-01-01

    The discovery of the gas cloud G2 on a near-radial orbit about Sgr A* has prompted much speculation on its origin. In this Letter, we propose that G2 formed out of the debris stream produced by the removal of mass from the outer envelope of a nearby giant star. We perform hydrodynamical simulations of the returning tidal debris stream with cooling and find that the stream condenses into clumps that fall periodically onto Sgr A*. We propose that one of these clumps is the observed G2 cloud, with the rest of the stream being detectable at lower Brγ emissivity along a trajectory that would trace from G2 to the star that was partially disrupted. By simultaneously fitting the orbits of S2, G2, and ∼2000 candidate stars, and by fixing the orbital plane of each candidate star to G2 (as is expected for a tidal disruption), we find that several stars have orbits that are compatible with the notion that one of them was tidally disrupted to produce G2. If one of these stars were indeed disrupted, it last encountered Sgr A* hundreds of years ago and has likely encountered Sgr A* repeatedly. However, while these stars are compatible with the giant disruption scenario given their measured positions and proper motions, their radial velocities are currently unknown. If one of these stars' radial velocity is measured to be compatible with a disruptive orbit, it would strongly suggest that its disruption produced G2

  14. Multiwavelength Coverage of a Bright Flare from Sgr A

    International Nuclear Information System (INIS)

    Trap, G.; Goldwurm, A.; Terrier, R.

    2009-01-01

    The dynamical center of our galaxy hosts a supermassive black hole, Sgr A*, which has been the target of an extensive multiwavelength campaign for a week in April 2007. We report here the detection of a bright flare from the vicinity of the horizon, observed simultaneously in X-rays (XMM-Newton) and NIR (VLT/NACO) on April 4 th . For the first time, such an event also benefitted from a soft γ-rays (INTEGRAL/ISGRI) and MIR (VLT/VISIR) coverage, which enabled us to derive upper limits at both ends of Sgr A* spectral energy distribution (SED). We discuss the physical implications of the contemporaneous light curves as well as the SED, in terms of synchrotron, synchrotron self-Compton and external Compton emission processes.

  15. Testing General Relativity with the Shadow Size of Sgr A(*).

    Science.gov (United States)

    Johannsen, Tim; Broderick, Avery E; Plewa, Philipp M; Chatzopoulos, Sotiris; Doeleman, Sheperd S; Eisenhauer, Frank; Fish, Vincent L; Genzel, Reinhard; Gerhard, Ortwin; Johnson, Michael D

    2016-01-22

    In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size may also depend strongly on parametric deviations from the Kerr metric. Based on a reconstructed image of Sagittarius A^{*} (Sgr A^{*}) from a simulated one-day observing run of a seven-station Event Horizon Telescope (EHT) array, we employ a Markov chain Monte Carlo algorithm to demonstrate that such an observation can measure the angular radius of the shadow of Sgr A^{*} with an uncertainty of ∼1.5  μas (6%). We show that existing mass and distance measurements can be improved significantly when combined with upcoming EHT measurements of the shadow size and that tight constraints on potential deviations from the Kerr metric can be obtained.

  16. PROSPECTS FOR PROBING THE SPACETIME OF Sgr A* WITH PULSARS

    Energy Technology Data Exchange (ETDEWEB)

    Liu, K.; Wex, N.; Kramer, M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Cordes, J. M. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Lazio, T. J. W. [Jet Propulsion Laboratory, California Institute of Technology, M/S 138-308, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2012-03-01

    The discovery of radio pulsars in compact orbits around Sgr A* would allow an unprecedented and detailed investigation of the spacetime of this supermassive black hole. This paper shows that pulsar timing, including that of a single pulsar, has the potential to provide novel tests of general relativity, in particular its cosmic censorship conjecture and no-hair theorem for rotating black holes. These experiments can be performed by timing observations with 100 {mu}s precision, achievable with the Square Kilometre Array for a normal pulsar at frequency above 15 GHz. Based on the standard pulsar timing technique, we develop a method that allows the determination of the mass, spin, and quadrupole moment of Sgr A*, and provides a consistent covariance analysis of the measurement errors. Furthermore, we test this method in detailed mock data simulations. It seems likely that only for orbital periods below {approx}0.3 yr is there the possibility of having negligible external perturbations. For such orbits, we expect a {approx}10{sup -3} test of the frame dragging and a {approx}10{sup -2} test of the no-hair theorem within five years, if Sgr A* is spinning rapidly. Our method is also capable of identifying perturbations caused by distributed mass around Sgr A*, thus providing high confidence in these gravity tests. Our analysis is not affected by uncertainties in our knowledge of the distance to the Galactic center, R{sub 0}. A combination of pulsar timing with the astrometric results of stellar orbits would greatly improve the measurement precision of R{sub 0}.

  17. Testing the No-Hair Theorem with Sgr A*

    Directory of Open Access Journals (Sweden)

    Tim Johannsen

    2012-01-01

    Full Text Available The no-hair theorem characterizes the fundamental nature of black holes in general relativity. This theorem can be tested observationally by measuring the mass and spin of a black hole as well as its quadrupole moment, which may deviate from the expected Kerr value. Sgr A*, the supermassive black hole at the center of the Milky Way, is a prime candidate for such tests thanks to its large angular size, high brightness, and rich population of nearby stars. In this paper, I discuss a new theoretical framework for a test of the no-hair theorem that is ideal for imaging observations of Sgr A* with very long baseline interferometry (VLBI. The approach is formulated in terms of a Kerr-like spacetime that depends on a free parameter and is regular everywhere outside of the event horizon. Together with the results from astrometric and timing observations, VLBI imaging of Sgr A* may lead to a secure test of the no-hair theorem.

  18. Shock interactions between Sgr A East and its environments

    International Nuclear Information System (INIS)

    Lee, Sungho; Pak, Soojong; Geballe, T R; Lee, Sang-Gak; Davis, Christopher J; Choi, Minho; Minh, Y C; Herrnstein, Robeson M; Ho, Paul T P

    2006-01-01

    We have surveyed the interaction regions between Sgr A East and the surrounding molecular clouds in the H 2 1-0 S(l) (2.1218 μm) line emission. The resulting data cube shows the distribution of the H 2 emission both in space (with a resolution of about 2 arcsec) and in velocity (with a resolution of about 18 km s -1 ). Our data are compared with NH 3 (3,3) data from radio observations to investigate the gas kinematics. Based on the H 2 1-0 S(l) line's intensity, its ratio to H 2 2 - 1 S(1), and its gas kinematics, we conclude that the emitting H 2 is excited by strong molecular shocks. We estimate shock velocities (≅ 100 km s -1 ) by comparing the H 2 line profles with those of NH 3 , and derive an initial explosion energy of 0.2 - 4 x 10 53 ergs. Such a high energy excludes a single normal supernova for the origin of Sgr A East. We examine other hypotheses, including the tidal disruption of a star by the supermassive black hole (Sgr A*), multiple supernovae, and a hypernova. We suggest that a hypernova, which is believed to originate from a collapsar or microquasar, is the most probable origin

  19. Long-term monitoring of Sgr A* at 7 mm with VERA and KaVA

    Science.gov (United States)

    Akiyama, K.; Kino, M.; Sohn, B.; Lee, S.; Trippe, S.; Honma, M.

    2014-05-01

    We present the results of radio monitoring observations of Sgr A* at 7 mm (i.e. 43 GHz) with the VLBI Exploration of Radio Astrometry (VERA), which is a VLBI array in Japan. VERA provides angular resolution on millisecond scales, resolving structures within 100 Schwarzschild radii of Sgr A* , similar to the Very Large Baseline Array (VLBA). We performed multi-epoch observations of Sgr A* in 2005 - 2008, and started monitoring it again with VERA from 2013 January to trace the current G2 encounter event. Our preliminary results in 2013 show that Sgr A* on mas scales has been in an ordinary state as of August 2013, although some fraction of the G2 cloud already passed the pericenter of Sgr A* in April 2013. We will continue monitoring Sgr A* with VERA and the newly developed KaVA (KVN and VERA Array).

  20. Fermi/GAMMA-RAY BURST MONITOR OBSERVATIONS OF SGR J0501+4516 BURSTS

    International Nuclear Information System (INIS)

    Lin Lin; Zhang Shuangnan; Kouveliotou, Chryssa; Baring, Matthew G.; Van der Horst, Alexander J.; Finger, Mark H.; Guiriec, Sylvain; Preece, Robert; Chaplin, Vandiver; Bhat, Narayan; Woods, Peter M.; Goegues, Ersin; Kaneko, Yuki; Scargle, Jeffrey; Granot, Jonathan; Von Kienlin, Andreas; Watts, Anna L.; Wijers, Ralph A. M. J.; Gehrels, Neil; Harding, Alice

    2011-01-01

    We present our temporal and spectral analyses of 29 bursts from SGR J0501+4516, detected with the gamma-ray burst monitor on board the Fermi Gamma-ray Space Telescope during 13 days of the source's activation in 2008 (August 22- September 3). We find that the T 90 durations of the bursts can be fit with a log-normal distribution with a mean value of ∼123 ms. We also estimate for the first time event durations of soft gamma repeater (SGR) bursts in photon space (i.e., using their deconvolved spectra) and find that these are very similar to the T 90 values estimated in count space (following a log-normal distribution with a mean value of ∼124 ms). We fit the time-integrated spectra for each burst and the time-resolved spectra of the five brightest bursts with several models. We find that a single power law with an exponential cutoff model fits all 29 bursts well, while 18 of the events can also be fit with two blackbody functions. We expand on the physical interpretation of these two models and we compare their parameters and discuss their evolution. We show that the time-integrated and time-resolved spectra reveal that E peak decreases with energy flux (and fluence) to a minimum of ∼30 keV at F = 8.7 x 10 -6 erg cm -2 s -1 , increasing steadily afterward. Two more sources exhibit a similar trend: SGRs J1550-5418 and 1806-20. The isotropic luminosity, L iso , corresponding to these flux values is roughly similar for all sources (0.4-1.5 x 10 40 erg s -1 ).

  1. Hard x-ray Morphological and Spectral Studies of the Galactic Center Molecular Cloud SGR B2: Constraining Past SGR A* Flaring Activity

    DEFF Research Database (Denmark)

    Zhang, Shuo; Hailey, Charles J.; Mori, Kaya

    2015-01-01

    In 2013, NuSTAR observed the Sgr B2 region and for the first time resolved its hard X-ray emission on subarcminute scales. Two prominent features are detected above 10 keV:. a newly emerging cloud, G0.66-0.13, and the central 90 '' radius region containing two compact cores, Sgr B2(M) and Sgr B2(N......), surrounded by diffuse emission. It is inconclusive whether the remaining level of Sgr. B2 emission is still decreasing or has reached a constant background level. A decreasing X-ray emission can be best explained by the X-ray reflection nebula scenario, where the cloud reprocesses a past giant outburst from...... Sgr A*. In the X-ray reflection nebula (XRN) scenario, the 3-79 keV Sgr. B2 spectrum allows us to self-consistently test the XRN model using both the Fe K alpha line and the continuum emission. The peak luminosity of the past Sgr A* outburst is constrained to L3-79keV∼5 x 1038 ergs s-1. A newly...

  2. LONG-TERM RADIATIVE BEHAVIOR OF SGR 1900+14

    International Nuclear Information System (INIS)

    Goegues, Ersin; Guever, Tolga; Oezel, Feryal; Eichler, David; Kouveliotou, Chryssa

    2011-01-01

    The prolific magnetar SGR 1900+14 showed two outbursts in the last decade and has been closely monitored in the X-rays to track the changes in its radiative properties. We use archival Chandra and XMM-Newton observations of SGR 1900+14 to construct a history of its spectrum and persistent X-ray flux spanning a period of about seven years. We show that the decline of its X-ray flux in these two outburst episodes follows the same trend. The flux begins to decline promptly and rapidly subsequent to the flares, then decreases gradually for about 600 days, at which point it resumes a more rapid decline. Utilizing the high-quality spectral data in each epoch, we also study the spectral coevolution of the source with its flux. We find that neither the magnetic field strength nor the magnetospheric properties change over the period spanned by the observations, while the surface temperature as well as the inferred emitting area both decline with time following both outbursts. We also show that the source reached the same minimum flux level in its decline from these two subsequent outbursts, suggesting that this flux level may be its steady quiescent flux.

  3. The Growth, Polarization, and Motion of the Radio Afterglow from the Giant Flare from SGR 1806-20

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G

    2005-04-20

    The extraordinary giant flare (GF) of 2004 December 27 from the soft gamma repeater (SGR) 1806-20 was followed by a bright radio afterglow. We present an analysis of VLA observations of this radio afterglow from SGR1806-20, consisting of previously reported 8.5 GHz data covering days 7 to 20 after the GF, plus new observations at 8.5 and 22 GHz from day 24 to 81. For a symmetric outflow, we find a deceleration in the expansion, from {approx}4.5 mas/day to <2.5 mas/day. The time of deceleration is roughly coincident with the rebrightening in the radio light curve, as expected to result when the ejecta from the GF sweeps up enough of the external medium, and transitions from a coasting phase to the Sedov-Taylor regime. The radio afterglow is elongated and maintains a 2:1 axis ratio with an average position angle of -40{sup o} (north through east), oriented perpendicular to the average intrinsic linear polarization angle. We also report on the discovery of motion in the flux centroid of the afterglow, at an average velocity of 0.26 {+-} 0.03 c (assuming a distance of 15 kpc) at a position angle of -45{sup o}. This motion, in combination with the growth and polarization measurements, suggests an initially asymmetric outflow, mainly from one side of the magnetar.

  4. CN in the Sgr A* environment - first results

    International Nuclear Information System (INIS)

    Stankovic, M; Seaquist, E R; Muehle, S

    2006-01-01

    The radical CN, through the CN/HCN ratio, has proven to be an exceptionally good tool to study the photodissociation regions (PDRs) dominated by FUV radiation. Our region of interest, the circumnuclear disk (CND) surrounding Sgr A*, is exposed to the strong UV radiation field originating from the central stellar cluster. It contains potentially star forming cores recently elucidated by interferometric HCN observations with OVRO by Christopher et al. (2005). We present the results of preliminary observations of CN (N = 2-l) transitions with the IRAM 30-m telescope and report, for the first time, detection of CN emission in the GC region indicative of PDR, activity. This work motivates the further investigation of the role of PDRs in the clumpy medium of the Galactic center (GC) environment in global photodissociation and in promoting or inhibiting star formation in the CND

  5. Dust Radiative Transfer Modeling of the Infrared Ring around the Magnetar SGR 1900+14

    Energy Technology Data Exchange (ETDEWEB)

    Natale, G. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Rea, N.; Torres, D. F.; Girart, J. M. [Institute of Space Sciences (IEEC–CSIC), Campus UAB, Carrer de Can Magrans S/N, E-08193 Barcelona (Spain); Lazzati, D. [Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, OR 97331 (United States); Perna, R., E-mail: gnatale@uclan.ac.uk [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

    2017-03-01

    A peculiar infrared ring-like structure was discovered by Spitzer around the strongly magnetized neutron star SGR 1900+14. This infrared (IR) structure was suggested to be due to a dust-free cavity, produced by the Soft Gamma-ray Repeaters (SGRs) Giant Flare occurring in 1998, and kept illuminated by surrounding stars. Using a 3D dust radiative transfer code, we aimed to reproduce the emission morphology and the integrated emission flux of this structure assuming different spatial distributions and densities for the dust, and different positions for the illuminating stars. We found that a dust-free ellipsoidal cavity can reproduce the shape, flux, and spectrum of the ring-like IR emission, provided that the illuminating stars are inside the cavity and that the interstellar medium has high gas density ( n {sub H} ∼ 1000 cm{sup −3}). We further constrain the emitting region to have a sharp inner boundary and to be significantly extended in the radial direction, possibly even just a cavity in a smooth molecular cloud. We discuss possible scenarios for the formation of the dustless cavity and the particular geometry that allows it to be IR-bright.

  6. Pre- and post-flight radiation performance evaluation of the space GPS receiver (SGR)

    International Nuclear Information System (INIS)

    Oldfield, M.K.; Underwood, C.I.; Unwin, M.J.; Asenek, V.; Harboe-Sorensen, R.

    1999-01-01

    SSTL (Survey Satellite Technology Ltd), in collaboration with ESA/ESTEC, recently developed a state-of-the-art low cost GPS (Global Positioning System) receiver payload for use on small satellites. The space GPS Receiver (SGR), will be flown on the TiungSAT-1 micro-satellite, UoSAT-12 mini-satellite and ESA's PROBA satellite. The SGR payload is currently flying on the TMSAT micro-satellite in low Earth orbit (LEO) and has carried out autonomous on-board positioning whilst also providing an experimental test-bed for evaluating spacecraft attitude determination algorithms. In order to reduce development time and costs, the SGR consists solely of industry standard COTS (commercial off-the-shelf) devices. This paper describes the ground-based radiation testing of several payload-critical COTS devices used in the SGR payload and describes its on-orbit performance. (authors)

  7. Depression variability at 5200 in the β Lyr and ν Sgr spectra

    International Nuclear Information System (INIS)

    Burnashev, V.I.; Skul'skij, M.Yu.

    1986-01-01

    Using the absolute spectrophotometrical data on binary stars β Lyr and ν Sgr the variability of depression at lambda 5200 dependent on the phase of orbital cycle has been studied. The variations of the equivalent width of the depression in the spectrum of β Lyr correlate with the magnetic field variations. The magnetic field strength of ν Sgr is predicted to be > or approximately 4 kGs

  8. Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A{sup *}

    Energy Technology Data Exchange (ETDEWEB)

    Yusef-Zadeh, F.; Royster, M. J.; Roberts, D. A. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Wardle, M. [Department of Physics and Astronomy and Research Center for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney NSW 2109 (Australia); Cotton, W.; Kunneriath, D. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Schödel, R. [Instituto de Astfisica de Andalucia (CSIC), Glorieta de la Astronomia S/N, E-18008 Granada (Spain)

    2017-03-01

    We present radio and millimeter continuum observations of the Galactic center taken with the Very Large Array (VLA) and ALMA at 44 and 226 GHz, respectively. We detect radio and millimeter emission from IRS 3, lying ∼4.″5 NW of Sgr A*, with a spectrum that is consistent with the photospheric emission from an AGB star at the Galactic center. Millimeter images reveal that the envelope of IRS 3, the brightest and most extended 3.8 μ m Galactic center stellar source, consists of two semicircular dust shells facing the direction of Sgr A*. The outer circumstellar shell, at a distance of 1.6 × 10{sup 4} au, appears to break up into “fingers” of dust directed toward Sgr A*. These features coincide with molecular CS (5–4) emission and a near-IR extinction cloud distributed between IRS 3 and Sgr A*. The NE–SW asymmetric shapes of the IRS 3 shells seen at 3.8 μ m and radio are interpreted as structures that are tidally distorted by Sgr A*. Using the kinematics of CS emission and the proper motion of IRS 3, the tidally distorted outflowing material from the envelope after 5000 yr constrains the distance of IRS 3 to ∼0.7 pc in front of or ∼0.5 pc behind Sgr A*. This suggests that the mass loss by stars near Sgr A* can supply a reservoir of molecular material near Sgr A*. We also present dark features in radio continuum images coincident with the envelope of IRS 3. These dusty stars provide examples in which high-resolution radio continuum images can identify dust-enshrouded stellar sources embedded in an ionized medium.

  9. The Parallax of the Red Hypergiant VX Sgr with Accurate Tropospheric Delay Calibration

    Science.gov (United States)

    Xu, Shuangjing; Zhang, Bo; Reid, Mark J.; Menten, Karl M.; Zheng, Xingwu; Wang, Guangli

    2018-05-01

    We report astrometric results of VLBI phase-referencing observations of 22 GHz H2O masers emission toward the red hypergiant VX Sgr, one of most massive and luminous red hypergiant stars in our Galaxy, using the Very Long Baseline Array. A background source, J1820‑2528, projected 4.°4 from the target VX Sgr, was used as the phase reference. For the low decl. of these sources, such a large separation normally would seriously degrade the relative astrometry. We use a two-step method of tropospheric delay calibration, which combines the VLBI geodetic-block (or Global Positioning System) calibration with an image-optimization calibration, to obtain a trigonometric parallax of 0.64 ± 0.04 mas, corresponding to a distance of {1.56}-0.10+0.11 kpc. The measured proper motion of VX Sgr is 0.36 ± 0.76 and ‑2.92 ± 0.78 mas yr‑1 in the eastward and northward directions. The parallax and proper motion confirms that VX Sgr belong to the Sgr OB1 association. Rescaling bolometric luminosities in the literature to our parallax distance, we find that the luminosity of VX Sgr is (1.95 ± 0.62) × 105 L ⊙, where the uncertainty is dominated by differing photometry measurements.

  10. The Small Protein SgrT Controls Transport Activity of the Glucose-Specific Phosphotransferase System.

    Science.gov (United States)

    Lloyd, Chelsea R; Park, Seongjin; Fei, Jingyi; Vanderpool, Carin K

    2017-06-01

    The bacterial small RNA (sRNA) SgrS has been a fruitful model for discovery of novel RNA-based regulatory mechanisms and new facets of bacterial physiology and metabolism. SgrS is one of only a few characterized dual-function sRNAs. SgrS can control gene expression posttranscriptionally via sRNA-mRNA base-pairing interactions. Its second function is coding for the small protein SgrT. Previous work demonstrated that both functions contribute to relief of growth inhibition caused by glucose-phosphate stress, a condition characterized by disrupted glycolytic flux and accumulation of sugar phosphates. The base-pairing activity of SgrS has been the subject of numerous studies, but the activity of SgrT is less well characterized. Here, we provide evidence that SgrT acts to specifically inhibit the transport activity of the major glucose permease PtsG. Superresolution microscopy demonstrated that SgrT localizes to the cell membrane in a PtsG-dependent manner. Mutational analysis determined that residues in the N-terminal domain of PtsG are important for conferring sensitivity to SgrT-mediated inhibition of transport activity. Growth assays support a model in which SgrT-mediated inhibition of PtsG transport activity reduces accumulation of nonmetabolizable sugar phosphates and promotes utilization of alternative carbon sources by modulating carbon catabolite repression. The results of this study expand our understanding of a basic and well-studied biological problem, namely, how cells coordinate carbohydrate transport and metabolism. Further, this work highlights the complex activities that can be carried out by sRNAs and small proteins in bacteria. IMPORTANCE Sequencing, annotation and investigation of hundreds of bacterial genomes have identified vast numbers of small RNAs and small proteins, the majority of which have no known function. In this study, we explore the function of a small protein that acts in tandem with a well-characterized small RNA during metabolic

  11. Massive binaries in the vicinity of Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Pfuhl, O.; Gillessen, S.; Genzel, R.; Eisenhauer, F.; Fritz, T. K.; Ott, T. [Max-Planck-Institut für Extraterrestrische Physik, D-85748 Garching (Germany); Alexander, T. [Faculty of Physics, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100 (Israel); Martins, F., E-mail: pfuhl@mpe.mpg.de [LUPM, Université Montpelier 2, CNRS, Place Eugéne Bataillon, F-34095, Montpellier (France)

    2014-02-20

    A long-term spectroscopic and photometric survey of the most luminous and massive stars in the vicinity of the supermassive black hole Sgr A* revealed two new binaries: a long-period Ofpe/WN9 binary, IRS 16NE, with a modest eccentricity of 0.3 and a period of 224 days, and an eclipsing Wolf-Rayet binary with a period of 2.3 days. Together with the already identified binary IRS 16SW, there are now three confirmed OB/WR binaries in the inner 0.2 pc of the Galactic center. Using radial velocity change upper limits, we were able to constrain the spectroscopic binary fraction in the Galactic center to F{sub SB}=0.30{sub −0.21}{sup +0.34} at a confidence level of 95%, a massive binary fraction close to that observed in dense clusters. The fraction of eclipsing binaries with photometric amplitudes Δm > 0.4 is F{sub EB}{sup GC}=3%±2%, which is consistent with local OB star clusters (F {sub EB} = 1%). Overall, the Galactic center binary fraction seems to be similar to the binary fraction in comparable young clusters.

  12. Lunar occultation observation of μ Sgr: A progress report

    Energy Technology Data Exchange (ETDEWEB)

    Jatmiko, A. T. P. [Bosscha Observatory, Institut Teknologi Bandung (Indonesia); Puannandra, G. P.; Hapsari, R. D.; Putri, R. A.; Arifin, Z. M.; Haans, G. K.; Hadiputrawan, I. P. W. [Bosscha Observatory, Institut Teknologi Bandung, Indonesia and Astronomy Study Program, Institut Teknologi Bandung (Indonesia)

    2014-03-24

    Lunar Occultation (LO) is an event where limb of the Moon passing over a particular heavenly bodies such as stars, asteroids, or planets. In other words, during the event, stars, asteroids and planets are occulted by the Moon. When occulted objects contact the lunar limb, there will be a diffraction fringe(s) which can be measured photometrically, until the signal vanishes into noise. This event will give us a valuable information about binarities (of stars) and/or angular diameters estimation (of stars, planets, asteroids) in milliarcsecond resolution, by fitting with theoretical LO pattern. CCDs are common for LO observation because of its fast read out, and recently are developed for sub-meter class telescope. In this paper, our LO observation attempt of μ Sgr and its progress report are presented. The observation was conducted on July 30{sup th}, 2012 at Bosscha Observatory, Indonesia, using 45cm f/12 GOTO telescope combined with ST-9 XE CCD camera and Bessel B filter. We used drift-scan method to obtain light curve of the star as it was disappearing behind Moon's dark limb. Our goal is to detect binarity (or multiplicity) of this particular object.

  13. Search for quasi-periodic signals in magnetar giant flares. Bayesian inspection of SGR 1806-20 and SGR 1900+14

    Science.gov (United States)

    Pumpe, Daniel; Gabler, Michael; Steininger, Theo; Enßlin, Torsten A.

    2018-02-01

    Quasi-periodic oscillations (QPOs) discovered in the decaying tails of giant flares of magnetars are believed to be torsional oscillations of neutron stars. These QPOs have a high potential to constrain properties of high-density matter. In search for quasi-periodic signals, we study the light curves of the giant flares of SGR 1806-20 and SGR 1900+14, with a non-parametric Bayesian signal inference method called D3PO. The D3PO algorithm models the raw photon counts as a continuous flux and takes the Poissonian shot noise as well as all instrument effects into account. It reconstructs the logarithmic flux and its power spectrum from the data. Using this fully noise-aware method, we do not confirm previously reported frequency lines at ν ≳ 17 Hz because they fall into the noise-dominated regime. However, we find two new potential candidates for oscillations at 9.2 Hz (SGR 1806-20) and 7.7 Hz (SGR 1900+14). If these are real and the fundamental magneto-elastic oscillations of the magnetars, current theoretical models would favour relatively weak magnetic fields B̅ 6× 1013-3 × 1014 G (SGR 1806-20) and a relatively low shear velocity inside the crust compared to previous findings. Data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A61

  14. RADIATIVE MODELS OF SGR A* FROM GRMHD SIMULATIONS

    International Nuclear Information System (INIS)

    Moscibrodzka, Monika; Gammie, Charles F.; Dolence, Joshua C.; Shiokawa, Hotaka; Leung, Po Kin

    2009-01-01

    Using flow models based on axisymmetric general relativistic magnetohydrodynamics simulations, we construct radiative models for Sgr A*. Spectral energy distributions (SEDs) that include the effects of thermal synchrotron emission and absorption, and Compton scattering, are calculated using a Monte Carlo technique. Images are calculated using a ray-tracing scheme. All models are scaled so that the 230 GHz flux density is 3.4 Jy. The key model parameters are the dimensionless black hole spin a * , the inclination i, and the ion-to-electron temperature ratio T i /T e . We find that (1) models with T i /T e = 1 are inconsistent with the observed submillimeter spectral slope; (2) the X-ray flux is a strongly increasing function of a * ; (3) the X-ray flux is a strongly increasing function of i; (4) 230 GHz image size is a complicated function of i, a * , and T i /T e , but the T i /T e = 10 models are generally large and at most marginally consistent with the 230 GHz very long baseline interferometry (VLBI) data; (5) for models with T i /T e = 10 and i = 85 deg. the event horizon is cloaked behind a synchrotron photosphere at 230 GHz and will not be seen by VLBI, but these models overproduce near-infrared and X-ray flux; (6) in all models whose SEDs are consistent with observations, the event horizon is uncloaked at 230 GHz; (7) the models that are most consistent with the observations have a * ∼ 0.9. We finish with a discussion of the limitations of our model and prospects for future improvements.

  15. Line Evolution of the Nova V5587 Sgr from Early to Nebula Phase

    Directory of Open Access Journals (Sweden)

    T. Kajikawa

    2015-02-01

    Full Text Available The spectral evolution of the nova V5587 Sgr has been monitored at Koyama Astronomical Observatory and Higashi-Hiroshima Observatory, Japan, from the early to nebula phase. The nova rebrightened several times. The spectra during the early phase showed emission lines of H α, H β, O I, He I, He II, N II, Fe II. Nova V5587 Sgr is classified into the Fe II type. The helium abundance of the nova is estimated as N(He/N(H = 0.134 ± 0.09. The light curve, the spectral evolution, and the helium abundance in V5587 Sgr are similar to those of the nova PW Vul.

  16. Action at the Horizon: Chandra/EHT Observations of Sgr A*

    Science.gov (United States)

    Neilsen, Joseph

    2017-09-01

    In April 2017, the Event Horizon Telescope will observe Sgr A* with imaging quality sufficient to resolve the shadow of the black hole, while providing a close-up view of accretion at the horizon. As Sgr A* is a well-known source of X-ray flares, coordinated Chandra/EHT observations offer an incredible opportunity: a chance to observe structures (e.g., hotspots) near the event horizon while tracking their high-energy variability. In anticipation of a follow-up campaign in 2018, we are requesting 4x33 ks Chandra observations of Sgr A* to be coordinated with EHT. This campaign will double our chances of simultaneous flares. We will search for flares and hotspots, provide priors for EHT image reconstruction, and track any activity associated with the closest approach of the massive star S0-2.

  17. Relative astrometry of compact flaring structures in Sgr A* with polarimetric very long baseline interferometry

    International Nuclear Information System (INIS)

    Johnson, Michael D.; Doeleman, Sheperd S.; Fish, Vincent L.; Broderick, Avery E.; Wardle, John F. C.; Marrone, Daniel P.

    2014-01-01

    We demonstrate that polarimetric interferometry can be used to extract precise spatial information about compact polarized flares of Sgr A*. We show that, for a faint dynamical component, a single interferometric baseline suffices to determine both its polarization and projected displacement from the quiescent intensity centroid. A second baseline enables two-dimensional reconstruction of the displacement, and additional baselines can self-calibrate using the flare, enhancing synthesis imaging of the quiescent emission. We apply this technique to simulated 1.3 mm wavelength observations of a 'hot spot' embedded in a radiatively inefficient accretion disk around Sgr A*. Our results indicate that, even with current sensitivities, polarimetric interferometry with the Event Horizon Telescope can achieve ∼5 μas relative astrometry of compact flaring structures near Sgr A* on timescales of minutes.

  18. Study of diffuse H II regions potentially forming part of the gas streams around Sgr A*

    Science.gov (United States)

    Armijos-Abendaño, J.; López, E.; Martín-Pintado, J.; Báez-Rubio, A.; Aravena, M.; Requena-Torres, M. A.; Martín, S.; Llerena, M.; Aldás, F.; Logan, C.; Rodríguez-Franco, A.

    2018-05-01

    We present a study of diffuse extended ionized gas towards three clouds located in the Galactic Centre (GC). One line of sight (LOS) is towards the 20 km s-1 cloud (LOS-0.11) in the Sgr A region, another LOS is towards the 50 km s-1 cloud (LOS-0.02), also in Sgr A, while the third is towards the Sgr B2 cloud (LOS+0.693). The emission from the ionized gas is detected from Hnα and Hmβ radio recombination lines (RRLs). Henα and Hemβ RRL emission is detected with the same n and m as those from the hydrogen RRLs only towards LOS+0.693. RRLs probe gas with positive and negative velocities towards the two Sgr A sources. The Hmβ to Hnα ratios reveal that the ionized gas is emitted under local thermodynamic equilibrium conditions in these regions. We find a He to H mass fraction of 0.29±0.01 consistent with the typical GC value, supporting the idea that massive stars have increased the He abundance compared to its primordial value. Physical properties are derived for the studied sources. We propose that the negative velocity component of both Sgr A sources is part of gas streams considered previously to model the GC cloud kinematics. Associated massive stars with what are presumably the closest H II regions to LOS-0.11 (positive velocity gas), LOS-0.02, and LOS+0.693 could be the main sources of ultraviolet photons ionizing the gas. The negative velocity components of both Sgr A sources might be ionized by the same massive stars, but only if they are in the same gas stream.

  19. Source-intrinsic near-infrared properties of Sgr A*: Total intensity measurements

    OpenAIRE

    Witzel, G.; Eckart, A.; Bremer, M.; Zamaninasab, M.; Shahzamanian, B.; Valencia-S., M.; Schödel, R.; Karas, V.; Lenzen, R.; Marchili, N.; Sabha, N.; Garcia-Marin, M.; Buchholz, R. M.; Kunneriath, D.; Straubmeier, C.

    2012-01-01

    We present a comprehensive data description for Ks-band measurements of Sgr A*. We characterize the statistical properties of the variability of Sgr A* in the near-infrared, which we find to be consistent with a single-state process forming a power-law distribution of the flux density. We discover a linear rms-flux relation for the flux-density range up to 12 mJy on a timescale of 24 minutes. This and the power-law flux density distribution implies a phenomenological, formally non-linear stat...

  20. Deployment Repeatability

    Science.gov (United States)

    2016-04-01

    evaluating the deployment repeatability builds upon the testing or analysis of deployment kinematics (Chapter 6) and adds repetition. Introduction...material yield or failure during a test. For the purposes of this chapter, zero shift will refer to permanent changes in the structure, while reversible ...the content of other chapters in this book: Gravity Compensation (Chapter 4) and Deployment Kinematics and Dynamics (Chapter 6). Repeating the

  1. An exceptionally bright flare from SGR 1806-20 and the origins of short-duration gamma-ray bursts.

    Science.gov (United States)

    Hurley, K; Boggs, S E; Smith, D M; Duncan, R C; Lin, R; Zoglauer, A; Krucker, S; Hurford, G; Hudson, H; Wigger, C; Hajdas, W; Thompson, C; Mitrofanov, I; Sanin, A; Boynton, W; Fellows, C; von Kienlin, A; Lichti, G; Rau, A; Cline, T

    2005-04-28

    Soft-gamma-ray repeaters (SGRs) are galactic X-ray stars that emit numerous short-duration (about 0.1 s) bursts of hard X-rays during sporadic active periods. They are thought to be magnetars: strongly magnetized neutron stars with emissions powered by the dissipation of magnetic energy. Here we report the detection of a long (380 s) giant flare from SGR 1806-20, which was much more luminous than any previous transient event observed in our Galaxy. (In the first 0.2 s, the flare released as much energy as the Sun radiates in a quarter of a million years.) Its power can be explained by a catastrophic instability involving global crust failure and magnetic reconnection on a magnetar, with possible large-scale untwisting of magnetic field lines outside the star. From a great distance this event would appear to be a short-duration, hard-spectrum cosmic gamma-ray burst. At least a significant fraction of the mysterious short-duration gamma-ray bursts may therefore come from extragalactic magnetars.

  2. Repeating Marx

    DEFF Research Database (Denmark)

    Fuchs, Christian; Monticelli, Lara

    2018-01-01

    This introduction sets out the context of the special issue “Karl Marx @ 200: Debating Capitalism & Perspectives for the Future of Radical Theory”, which was published on the occasion of Marx’s bicentenary on 5 May 2018. First, we give a brief overview of contemporary capitalism’s development...... and its crises. Second, we argue that it is important to repeat Marx today. Third, we reflect on lessons learned from 200 years of struggles for alternatives to capitalism. Fourth, we give an overview of the contributions in this special issue. Taken together, the contributions in this special issue show...... that Marx’s theory and politics remain key inspirations for understanding exploitation and domination in 21st-century society and for struggles that aim to overcome these phenomena and establishing a just and fair society. We need to repeat Marx today....

  3. Deployment Repeatability

    Science.gov (United States)

    2016-08-31

    large cohort of trials to spot unusual cases. However, deployment repeatability is inherently a nonlinear phenomenon, which makes modeling difficult...and GEMS tip position were both tracked during ground testing by a laser target tracking system. Earlier SAILMAST testing in 2005 [8] used...recalls the strategy used by SRTM, where a constellation of lights was installed at the tip of the boom and a modified star tracker was used to track tip

  4. A new study of the interacting binary star V356 Sgr

    Science.gov (United States)

    Polidan, R. S.

    1988-01-01

    Results on V356 Sgr from IUE and Voyager ultraviolet (500 to 3200 A) observations obtained in 1986 and 1987, primarily during 2 total eclipses are presented. The eclipse of Aug. 15, 1986 was fully covered with IUE low dispersion images and 9 hr of Voyager UVS data. The eclipse of Mar. 25, 1987 was covered with IUE low dispersion images and 1 high dispersion SWP image. During both eclipses the total strength of the emission lines is found to be invariant. An uneclipsed UV continuum is detected at wavelengths shorter than 1500 A. The high dispersion SWP spectrum reveals that the emission lines are extremely broad, almost symmetrical emissions with weak, slightly blue shifted absorption components. No evidence of carbon, C I, C II, C III, or C IV, is seen in the emission or absorption spectrum of V356 Sgr in eclipse. Models for this binary system are presented.

  5. GBT Measurements of the Physical Properties of the Sgr B2 Region

    Science.gov (United States)

    Langston, Glen; Schmidt, D. R.; Christiansen, K.

    2012-01-01

    We present NRAO GBT observations of ammonia 1-1 and 2-2 emission in the Sgr B2 region, in order to estimate the physical temperature of this region. The observations were made with the 7-beam K-band Focal Plane Array (KFPA) collecting spectra over a 11' by 9' region. We compare these observations with molecular line spectra obtained with the GBT in the frequency range 12.4 to 15.0 GHz. In this frequency range, Hydrogen α, β, and γ recombination lines, Helium α recombination lines and emission from the SO molecule are detected. Molecular absorption lines from OH, H2CO and CH3CO are detected at velocity 62×3 km/sec. Measurements of the line widths and intensities are presented for the central region of Sgr B2.

  6. Six Years of Monitoring of the Sgr B2 Molecular Cloud with INTEGRAL

    Science.gov (United States)

    Terrier, R.; Bélanger, G.; Ponti, G.; Trap, G.; Goldwurm, A.; Decourchelle, A.

    2009-05-01

    Several molecular clouds around the Galactic Centre (GC) emit strong neutral iron fluorescence line at 6.4 keV, as well as hard X-ray emission up to 100 keV. The origin of this emission has long been a matter of controversy: irradiation by low energy cosmic ray electrons or X-rays emitted by a nearby flaring source in the central region. A recent evidence for time variability in the iron line intensity that has been detected in the Sgr B2 cloud favors the reflexion scenario. We present here the data obtained after 6 years of INTEGRAL monitoring of the GC. In particular, we show a lightcurve of Sgr B2 that reveals a decrease in the hard X-ray flux over the last years and discuss its implications. We finally discuss perspectives with Simbol-X.

  7. Depression of molecular emission in the line of sight of Sgr A West

    International Nuclear Information System (INIS)

    Fukui, Y.; Ogawa, H.; Deguchi, S.; Suzuki, H.

    1982-01-01

    The galatic center region has been mapped in the 4-mm emission lines of HCCCN (J = 8-7) and H 2 CO (JK-K+ = 1 01 -0 00 ) with a 1.5 arc min beam. The molecular lines are found to show depression in intensity in the line of sight of Sgr A West. Comparison with other molecular data indicates that NH 3 also shows a significant depression while HCN and HCO + show little sign of similar depression. Based on some density estimates we suggest that the depression means abnormally reduced abundance in HCCCN, NH 3 , and H 2 CO in the line of sight of Sgr A West. The difference in the degree of depression could be interpreted in terms of a time-dependent ion-molecule reaction scheme because HCO + and HCN are formed much more rapidly than the other molecules in the scheme

  8. Fermi bubbles inflated by winds launched from the hot accretion flow in Sgr A*

    International Nuclear Information System (INIS)

    Mou, Guobin; Yuan, Feng; Bu, Defu; Sun, Mouyuan; Su, Meng

    2014-01-01

    A pair of giant gamma-ray Bubbles has been revealed by Fermi-LAT. In this paper we investigate their formation mechanism. Observations have indicated that the activity of the supermassive black hole located at the Galactic center, Sgr A*, was much stronger than at the present time. Specifically, one possibility is that while Sgr A* was also in the hot accretion regime, the accretion rate should be 10 3 -10 4 times higher during the past ∼10 7 yr. On the other hand, recent magnetohydrodynamic numerical simulations of hot accretion flows have unambiguously shown the existence and obtained the properties of strong winds. Based on this knowledge, by performing three-dimensional hydrodynamical simulations, we show in this paper that the Fermi Bubbles could be inflated by winds launched from the 'past' hot accretion flow in Sgr A*. In our model, the active phase of Sgr A* is required to last for about 10 million years and it was quenched no more than 0.2 million years ago. The central molecular zone (CMZ) is included and it collimates the wind orientation toward the Galactic poles. Viscosity suppresses the Rayleigh-Taylor and Kelvin-Helmholtz instabilities and results in the smoothness of the Bubbles edge. The main observational features of the Bubbles can be well explained. Specifically, the ROSAT X-ray features are interpreted by the shocked interstellar medium and the interaction region between the wind and CMZ gas. The thermal pressure and temperature obtained in our model are consistent with recent Suzaku observations.

  9. Groundwater Seepage Estimation into Amirkabir Tunnel Using Analytical Methods and DEM and SGR Method

    OpenAIRE

    Hadi Farhadian; Homayoon Katibeh

    2015-01-01

    In this paper, groundwater seepage into Amirkabir tunnel has been estimated using analytical and numerical methods for 14 different sections of the tunnel. Site Groundwater Rating (SGR) method also has been performed for qualitative and quantitative classification of the tunnel sections. The obtained results of above mentioned methods were compared together. The study shows reasonable accordance with results of the all methods unless for two sections of tunnel. In these t...

  10. RADIO NONDETECTION OF THE SGR 1806−20 GIANT FLARE AND IMPLICATIONS FOR FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Tendulkar, Shriharsh P.; Kaspi, Victoria M.; Patel, Chitrang

    2016-01-01

    We analyze archival data from the Parkes radio telescope, which was observing a location 35.°6 away from SGR 1806−20 during its giant γ -ray flare of 2004 December 27. We show that no fast radio burst (FRB)-like burst counterpart was detected, and set a radio limit of 110 MJy at 1.4 GHz, including the estimated 70 dB suppression of the signal due to its location in the far sidelobe of Parkes and the predicted scattering from the interstellar medium. The upper limit for the ratio of magnetar giant flare radio to γ -ray fluence is η SGR ≲ 10 7 Jy ms erg −1 cm 2 . Based on the nondetection of a short and prompt γ -ray counterpart of 15 FRBs in γ -ray transient monitors, we set a lower limit on the fluence ratios of FRBs to be η FRB ≳ 10 7–9 Jy ms erg −1 cm 2 . The fluence ratio limit for SGR 1806−20 is inconsistent with all but one of the 15 FRBs. We discuss possible variations in the magnetar-FRB emission mechanism and observational caveats that may reconcile the theory with observations.

  11. Time Domain Filtering of Resolved Images of Sgr A{sup ∗}

    Energy Technology Data Exchange (ETDEWEB)

    Shiokawa, Hotaka; Doeleman, Sheperd S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Gammie, Charles F. [Department of Physics, University of Illinois, 1110 West Green Street, Urbana, IL 61801 (United States)

    2017-09-01

    The goal of the Event Horizon Telescope (EHT) is to provide spatially resolved images of Sgr A*, the source associated with the Galactic Center black hole. Because Sgr A* varies on timescales that are short compared to an EHT observing campaign, it is interesting to ask whether variability contains information about the structure and dynamics of the accretion flow. In this paper, we introduce “time-domain filtering,” a technique to filter time fluctuating images with specific temporal frequency ranges and to demonstrate the power and usage of the technique by applying it to mock millimeter wavelength images of Sgr A*. The mock image data is generated from the General Relativistic Magnetohydrodynamic (GRMHD) simulation and the general relativistic ray-tracing method. We show that the variability on each line of sight is tightly correlated with a typical radius of emission. This is because disk emissivity fluctuates on a timescale of the order of the local orbital period. Time-domain filtered images therefore reflect the model dependent emission radius distribution, which is not accessible in time-averaged images. We show that, in principle, filtered data have the power to distinguish between models with different black-hole spins, different disk viewing angles, and different disk orientations in the sky.

  12. Approaching the event horizon: 1.3mmλ VLBI of SgrA*

    International Nuclear Information System (INIS)

    Doeleman, Sheperd

    2008-01-01

    Advances in VLBI instrumentation now allow wideband recording that significantly increases the sensitivity of short wavelength VLBI observations. Observations of the super-massive black hole candidate at the center of the Milky Way, SgrA*, with short wavelength VLBI reduces the scattering effects of the intervening interstellar medium, allowing observations with angular resolution comparable to the apparent size of the event horizon of the putative black hole. Observations in April 2007 at a wavelength of 1.3mm on a three station VLBI array have now confirmed structure in SgrA* on scales of just a few Schwarzschild radii. When modeled as a circular Gaussian, the fitted diameter of SgrA* is 37 μas (+16,-10; 3σ), which is smaller than the expected apparent size of the event horizon of the Galactic Center black hole. These observations demonstrate that mm/sub-mm VLBI is poised to open a new window onto the study of black hole physics via high angular resolution observations of the Galactic Center.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-01

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

  14. RADIO NONDETECTION OF THE SGR 1806−20 GIANT FLARE AND IMPLICATIONS FOR FAST RADIO BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Tendulkar, Shriharsh P.; Kaspi, Victoria M.; Patel, Chitrang, E-mail: shriharsh@physics.mcgill.ca [Department of Physics and McGill Space Institute, 3600 University St., Montréal, QC H3A 2A8 (Canada)

    2016-08-10

    We analyze archival data from the Parkes radio telescope, which was observing a location 35.°6 away from SGR 1806−20 during its giant γ -ray flare of 2004 December 27. We show that no fast radio burst (FRB)-like burst counterpart was detected, and set a radio limit of 110 MJy at 1.4 GHz, including the estimated 70 dB suppression of the signal due to its location in the far sidelobe of Parkes and the predicted scattering from the interstellar medium. The upper limit for the ratio of magnetar giant flare radio to γ -ray fluence is η {sub SGR} ≲ 10{sup 7} Jy ms erg{sup −1} cm{sup 2}. Based on the nondetection of a short and prompt γ -ray counterpart of 15 FRBs in γ -ray transient monitors, we set a lower limit on the fluence ratios of FRBs to be η {sub FRB} ≳ 10{sup 7–9} Jy ms erg{sup −1} cm{sup 2}. The fluence ratio limit for SGR 1806−20 is inconsistent with all but one of the 15 FRBs. We discuss possible variations in the magnetar-FRB emission mechanism and observational caveats that may reconcile the theory with observations.

  15. Perils at the heart of the Milky Way: Systematic effects for studying low-luminosity accretion onto Sgr A*

    Science.gov (United States)

    Corrales, Lia; Mon, Brayden; Haggard, Daryl; Baganoff, Frederick K.; Garmire, Gordon; Degenaar, Nathalie; Reynolds, Mark

    2017-08-01

    The supermassive black hole at the center of our galaxy, Sgr A*, is surprisingly under-luminous. This problem has motivated a host of theoretical models to explain low-level radiatively inefficient accretion flows onto compact objects. We discuss how the Galactic Center sight line, which is optically thick to the scattering of soft X-rays (tau ~ 5), affects high resolution studies of the accretion flow around Sgr A*. X-ray light from compact objects in the dense GC environment is scattered by foreground dust, producing scattering echoes that are time delayed relative to the X-ray source's light curve. We discuss the scattering halo of SWIFT J174540.7-290015, which underwent the brightest X-ray outburst within 30’' of Sgr A*. Preliminary fits to the scattering halo suggest that a small amount of foreground dust, within 250 pc of the GC, affects the X-ray surface brightness profile within 10’' of any GC point source. The associated time delay is on the order of several hours, which is important for understanding the quiescent accretion flow of Sgr A*. We take advantage of the Chandra Galactic Center XVP dataset to explore the effect of the interstellar medium on the inferred characteristics of Sgr A*.

  16. AN IMPROVED DISTANCE AND MASS ESTIMATE FOR SGR A* FROM A MULTISTAR ORBIT ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Boehle, A.; Ghez, A. M.; Meyer, L.; Yelda, S.; Albers, S.; Martinez, G. D.; Becklin, E. E.; Do, T.; Morris, M. R.; Sitarski, B.; Witzel, G. [UCLA, Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); Schödel, R. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía S/N, E-18008 Granada (Spain); Lu, J. R. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Matthews, K., E-mail: aboehle@astro.ucla.edu [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, MC 301-17, Pasadena, CA 91125 (United States)

    2016-10-10

    We present new, more precise measurements of the mass and distance of our Galaxy’s central supermassive black hole, Sgr A*. These results stem from a new analysis that more than doubles the time baseline for astrometry of faint stars orbiting Sgr A*, combining 2 decades of speckle imaging and adaptive optics data. Specifically, we improve our analysis of the speckle images by using information about a star’s orbit from the deep adaptive optics data (2005–2013) to inform the search for the star in the speckle years (1995–2005). When this new analysis technique is combined with the first complete re-reduction of Keck Galactic Center speckle images using speckle holography, we are able to track the short-period star S0-38 ( K -band magnitude = 17, orbital period = 19 yr) through the speckle years. We use the kinematic measurements from speckle holography and adaptive optics to estimate the orbits of S0-38 and S0-2 and thereby improve our constraints of the mass ( M {sub bh}) and distance ( R {sub o} ) of Sgr A*: M {sub bh} = (4.02 ± 0.16 ± 0.04) × 10{sup 6} M {sub ⊙} and 7.86 ± 0.14 ± 0.04 kpc. The uncertainties in M {sub bh} and R {sub o} as determined by the combined orbital fit of S0-2 and S0-38 are improved by a factor of 2 and 2.5, respectively, compared to an orbital fit of S0-2 alone and a factor of ∼2.5 compared to previous results from stellar orbits. This analysis also limits the extended dark mass within 0.01 pc to less than 0.13 × 10{sup 6} M {sub ⊙} at 99.7% confidence, a factor of 3 lower compared to prior work.

  17. Testing a class of non-Kerr metrics with hot spots orbiting SgrA*

    International Nuclear Information System (INIS)

    Liu, Dan; Li, Zilong; Bambi, Cosimo

    2015-01-01

    SgrA*, the supermassive black hole candidate at the Galactic Center, exhibits flares in the X-ray, NIR, and sub-mm bands that may be interpreted within a hot spot model. Light curves and images of hot spots orbiting a black hole are affected by a number of special and general relativistic effects, and they can be potentially used to check whether the object is a Kerr black hole of general relativity. However, in a previous study we have shown that the relativistic features are usually subdominant with respect to the background noise and the model-dependent properties of the hot spot, and eventually it is at most possible to estimate the frequency of the innermost stable circular orbit. In this case, tests of the Kerr metric are only possible in combination with other measurements. In the present work, we consider a class of non-Kerr spacetimes in which the hot spot orbit may be outside the equatorial plane. These metrics are difficult to constrain from the study of accretion disks and indeed current X-ray observations of stellar-mass and supermassive black hole candidates cannot put interesting bounds. Here we show that near future observations of SgrA* may do it. If the hot spot is sufficiently close to the massive object, the image affected by Doppler blueshift is brighter than the other one and this provides a specific observational signature in the hot spot's centroid track. We conclude that accurate astrometric observations of SgrA* with an instrument like GRAVITY should be able to test this class of metrics, except in the more unlikely case of a small viewing angle

  18. Imaging the Molecular Disk Orbiting the Twin Suns of V4046 Sgr

    Science.gov (United States)

    Rodriguez, David R.; Kastner, J. H.; Wilner, D. J.; Zuckerman, B.

    2009-05-01

    V4046 Sgr is a 12 Myr-old spectroscopic binary with a period of 2.4 days. At a distance of 73 pc (Torres et al. 2008), it is the second closest classical T Tauri star to the Earth after TW Hydra. Previously, rotational transitions of CO, HCO+, CN, and HCN were detected with the 30m IRAM telescope (Kastner et al. 2008). The double peaked CO profiles can be fit by a model invoking a Keplerian disk with outer radius of 250 AU that is viewed at an inclination of 35 degrees. The CO line profile was asymmetric, with the redshifted emission peak in both C-12 and C-13 brighter than the blueshifted peak. We have used the SMA to spatially resolve the J=2-1 CO emission line and the 230 GHz continuum. The CO channel maps show a disk consistent with Keplerian rotation. At the velocity of the redshifted emission peak, these observations reveal enhanced CO emission a few arcseconds to the southwest of the binary. A question arises as to whether this enhanced CO emission is associated with a third star in the system. According to the analysis of Tokovinin et al. (2006), the probability that a binary with a 2.4 day period has an associated tertiary star is essentially 100%. We searched archival Chandra and HST (ACS and NICMOS) images in the vicinity of V4046 Sgr to look for a star at the position of the enhanced CO emission. While there is a star in the HST ACS images approximately coincident with the enhanced CO emission, our preliminary analysis suggests that this star is not physically associated with V4046 Sgr. We will present a detailed discussion of the SMA results. This work has been partially supported by a NASA ADA grant to RIT and UCLA.

  19. SMM hard X-ray observations of the soft gamma-ray repeater 1806-20

    Science.gov (United States)

    Kouveliotou, C.; Norris, J. P.; Cline, T. L.; Dennis, B. R.; Desai, U. D.; Orwig, L. E.

    1987-01-01

    Six bursts from the soft gamma-ray repeater (SGR) 1806-20 have been recorded with the SMM Hard X-ray Burst Spectrometer during a highly active phase in 1983. Rise and decay times of less than 5 ns have been detected. Time profiles of these events indicate low-level emission prior to and after the main peaks. The results suggest that SGRs are distinguished from classical gamma-ray bursts by repetition, softer nonvarying spectra, short durations, simple temporal profiles, and a tendency for source locations to correlate with Population I objects. SGR characteristics differ from those of type I X-ray bursts, but they appear to have similarities with the type II bursts from the Rapid Burster.

  20. SMM hard X-ray observations of the soft gamma-ray repeater 1806-20

    International Nuclear Information System (INIS)

    Kouveliotou, C.; Norris, J.P.; Cline, T.L.; Dennis, B.R.; Desai, U.D.; Orwig, L.E.

    1987-01-01

    Six bursts from the soft gamma-ray repeater (SGR) 1806-20 have been recorded with the SMM Hard X-ray Burst Spectrometer during a highly active phase in 1983. Rise and decay times of less than 5 ns have been detected. Time profiles of these events indicate low-level emission prior to and after the main peaks. The results suggest that SGRs are distinguished from classical gamma-ray bursts by repetition, softer nonvarying spectra, short durations, simple temporal profiles, and a tendency for source locations to correlate with Population I objects. SGR characteristics differ from those of type I X-ray bursts, but they appear to have similarities with the type II bursts from the Rapid Burster. 19 references

  1. Testing General Relativity with High-Resolution Imaging of Sgr A*

    International Nuclear Information System (INIS)

    Broderick, Avery E; Loeb, Abraham

    2006-01-01

    Submilliarcsecond astrometry and imaging of the black hole Sgr A* at the Galactic Center may become possible in the near future at infrared and submillimetre wavelengths. This resolution is sufficient to observe the silhouette the supermassive black hole in the Galactic center casts upon background emission. However, more exciting is the prospect of observing 'hot spots' in the accretion fbw. Here we discuss how such measurements may be used to test not only the consistency of General Relativity, but also the validity of the Kerr metric in particular

  2. Testing General Relativity with High-Resolution Imaging of Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Avery E; Loeb, Abraham [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, 02145 (United States)

    2006-12-15

    Submilliarcsecond astrometry and imaging of the black hole Sgr A* at the Galactic Center may become possible in the near future at infrared and submillimetre wavelengths. This resolution is sufficient to observe the silhouette the supermassive black hole in the Galactic center casts upon background emission. However, more exciting is the prospect of observing 'hot spots' in the accretion fbw. Here we discuss how such measurements may be used to test not only the consistency of General Relativity, but also the validity of the Kerr metric in particular.

  3. The Outburst Decay of the Low Magnetic Field Magnetar SGR 0418+5729

    Science.gov (United States)

    Rea, N.; Israel, G. L.; Pons, J. A.; Turolla, R.; Viganò, D.; Zane, S.; Esposito, P.; Perna, R.; Papitto, A.; Terreran, G.; Tiengo, A.; Salvetti, D.; Girart, J. M.; Palau, Aina; Possenti, A.; Burgay, M.; Göğüş, E.; Caliandro, G. A.; Kouveliotou, C.; Götz, D.; Mignani, R. P.; Ratti, E.; Stella, L.

    2013-06-01

    We report on the long-term X-ray monitoring of the outburst decay of the low magnetic field magnetar SGR 0418+5729 using all the available X-ray data obtained with RXTE, Swift, Chandra, and XMM-Newton observations from the discovery of the source in 2009 June up to 2012 August. The timing analysis allowed us to obtain the first measurement of the period derivative of SGR 0418+5729: \\dot{P}=4(1)\\times 10^{-15} s s-1, significant at a ~3.5σ confidence level. This leads to a surface dipolar magnetic field of B dip ~= 6 × 1012 G. This measurement confirms SGR 0418+5729 as the lowest magnetic field magnetar. Following the flux and spectral evolution from the beginning of the outburst up to ~1200 days, we observe a gradual cooling of the tiny hot spot responsible for the X-ray emission, from a temperature of ~0.9 to 0.3 keV. Simultaneously, the X-ray flux decreased by about three orders of magnitude: from about 1.4 × 10-11 to 1.2 × 10-14 erg s-1 cm-2. Deep radio, millimeter, optical, and gamma-ray observations did not detect the source counterpart, implying stringent limits on its multi-band emission, as well as constraints on the presence of a fossil disk. By modeling the magneto-thermal secular evolution of SGR 0418+5729, we infer a realistic age of ~550 kyr, and a dipolar magnetic field at birth of ~1014 G. The outburst characteristics suggest the presence of a thin twisted bundle with a small heated spot at its base. The bundle untwisted in the first few months following the outburst, while the hot spot decreases in temperature and size. We estimate the outburst rate of low magnetic field magnetars to be about one per year per galaxy, and we briefly discuss the consequences of such a result in several other astrophysical contexts.

  4. THE OUTBURST DECAY OF THE LOW MAGNETIC FIELD MAGNETAR SGR 0418+5729

    International Nuclear Information System (INIS)

    Rea, N.; Papitto, A.; Terreran, G.; Girart, J. M.; Palau, Aina; Caliandro, G. A.; Israel, G. L.; Pons, J. A.; Viganò, D.; Turolla, R.; Zane, S.; Esposito, P.; Tiengo, A.; Salvetti, D.; Perna, R.; Possenti, A.; Burgay, M.; Göğüş, E.; Kouveliotou, C.; Götz, D.

    2013-01-01

    We report on the long-term X-ray monitoring of the outburst decay of the low magnetic field magnetar SGR 0418+5729 using all the available X-ray data obtained with RXTE, Swift, Chandra, and XMM-Newton observations from the discovery of the source in 2009 June up to 2012 August. The timing analysis allowed us to obtain the first measurement of the period derivative of SGR 0418+5729: P-dot =4(1)×10 -15 s s –1 , significant at a ∼3.5σ confidence level. This leads to a surface dipolar magnetic field of B dip ≅ 6 × 10 12 G. This measurement confirms SGR 0418+5729 as the lowest magnetic field magnetar. Following the flux and spectral evolution from the beginning of the outburst up to ∼1200 days, we observe a gradual cooling of the tiny hot spot responsible for the X-ray emission, from a temperature of ∼0.9 to 0.3 keV. Simultaneously, the X-ray flux decreased by about three orders of magnitude: from about 1.4 × 10 –11 to 1.2 × 10 –14 erg s –1 cm –2 . Deep radio, millimeter, optical, and gamma-ray observations did not detect the source counterpart, implying stringent limits on its multi-band emission, as well as constraints on the presence of a fossil disk. By modeling the magneto-thermal secular evolution of SGR 0418+5729, we infer a realistic age of ∼550 kyr, and a dipolar magnetic field at birth of ∼10 14 G. The outburst characteristics suggest the presence of a thin twisted bundle with a small heated spot at its base. The bundle untwisted in the first few months following the outburst, while the hot spot decreases in temperature and size. We estimate the outburst rate of low magnetic field magnetars to be about one per year per galaxy, and we briefly discuss the consequences of such a result in several other astrophysical contexts.

  5. BURST TAILS FROM SGR J1550–5418 OBSERVED WITH THE ROSSI X-RAY TIMING EXPLORER

    Energy Technology Data Exchange (ETDEWEB)

    Muş, Sinem Şaşmaz; Gögüş, Ersin; Kaneko, Yuki; Chakraborty, Manoneeta; Aydın, Berk, E-mail: sinemsmus@sabanciuniv.edu [Sabancı University, Faculty of Engineering and Natural Sciences, Orhanlı Tuzla 34956 Istanbul (Turkey)

    2015-07-01

    We present the results of our extensive search using the Bayesian block method for long tails following short bursts from a magnetar, SGR J1550–5418, over all RXTE observations of the source. We identified four bursts with extended tails, most of which occurred during its 2009 burst active episode. The durations of tails range between ∼13 s and over 3 ks, which are much longer than the typical duration of bursts. We performed detailed spectral and temporal analyses of the burst tails. We find that the spectra of three tails show a thermal nature with a trend of cooling throughout the tail. We compare the results of our investigations with the properties of four other extended tails detected from SGR 1900+14 and SGR 1806–20 and suggest a scenario for the origin of the tail in the framework of the magnetar model.

  6. The X-ray outburst of the Galactic Centre magnetar SGR J1745-2900 during the first 1.5 year

    NARCIS (Netherlands)

    Coti Zelati, F.; Rea, N.; Papitto, A.; Viganò, D.; Pons, J.A.; Turolla, R.; Esposito, P.; Haggard, D.; Baganoff, F.K.; Ponti, G.; Israel, G.L.; Campana, S.; Torres, D.F.; Tiengo, A.; Mereghetti, S.; Perna, R.; Zane, S.; Mignani, R.P.; Possenti, A.; Stella, L.

    2015-01-01

    In 2013 April a new magnetar, SGR 1745−2900, was discovered as it entered an outburst, at only 2.4 arcsec angular distance from the supermassive black hole at the centre of the Milky Way, Sagittarius A*. SGR 1745−2900 has a surface dipolar magnetic field of ∼2 × 1014 G, and it is the neutron star

  7. Polarization and long-term variability of Sgr A* X-ray echo

    Science.gov (United States)

    Churazov, E.; Khabibullin, I.; Ponti, G.; Sunyaev, R.

    2017-06-01

    We use a model of the molecular gas distribution within ˜100 pc from the centre of the Milky Way (Kruijssen, Dale & Longmore) to simulate time evolution and polarization properties of the reflected X-ray emission, associated with the past outbursts from Sgr A*. While this model is too simple to describe the complexity of the true gas distribution, it illustrates the importance and power of long-term observations of the reflected emission. We show that the variable part of X-ray emission observed by Chandra and XMM-Newton from prominent molecular clouds is well described by a pure reflection model, providing strong support of the reflection scenario. While the identification of Sgr A* as a primary source for this reflected emission is already a very appealing hypothesis, a decisive test of this model can be provided by future X-ray polarimetric observations, which will allow placing constraints on the location of the primary source. In addition, X-ray polarimeters (like, e.g. XIPE) have sufficient sensitivity to constrain the line-of-sight positions of molecular complexes, removing major uncertainty in the model.

  8. DISCOVERY OF SUBSTRUCTURE IN THE SCATTER-BROADENED IMAGE OF SGR A*

    Energy Technology Data Exchange (ETDEWEB)

    Gwinn, C. R. [Physics Department, Broida Hall, University of California, Santa Barbara, CA 93117 (United States); Kovalev, Y. Y.; Soglasnov, V. A. [Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences, Profsoyuznaya Str. 84/32, Moscow 117997 (Russian Federation); Johnson, M. D., E-mail: cgwinn@physics.ucsb.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-10-10

    We have detected substructure within the smooth scattering disk of the celebrated Galactic center radio source Sagittarius A* (Sgr A*). We observed this structure at 1.3 cm wavelength with the Very Long Baseline Array together with the Green Bank Telescope, on baselines of up to 3000 km, long enough to completely resolve the average scattering disk. Such structure is predicted theoretically as a consequence of refraction by large-scale plasma fluctuations in the interstellar medium. Along with the much-studied θ{sub d}∝λ{sup 2} scaling of angular broadening θ{sub d} with observing wavelength λ, our observations indicate that the spectrum of interstellar turbulence is shallow with an inner scale larger than 300 km. The substructure is consistent with an intrinsic size of about 1 mas at 1.3 cm wavelength, as inferred from deconvolution of the average scattering. Further observations of the substructure can set stronger constraints on the properties of scattering material and on the intrinsic size of Sgr A*. These constraints will guide our understanding of the effects of scatter broadening and the emission physics near the black hole in images with the Event Horizon Telescope at millimeter wavelengths.

  9. G2 and Sgr A *: A Cosmic Fizzle at the Galactic Center

    Energy Technology Data Exchange (ETDEWEB)

    Morsony, Brian J. [Dept. of Astronomy, University of Maryland, 1113 Physical Sciences Complex, College Park, MD, 20742-2421 (United States); Gracey, Brandon T.; Workman, Jared C. [Dept. of Physical and Environmental Sciences, Colorado Mesa University, Grand Junction, CO, 81501 (United States); Yoon, DooSoo [Dept. of Astronomy, University of Wisconsin-Madison, 2535 Sterling Hall, 475 N. Charter Street, Madison, WI, 53706-1582 (United States)

    2017-07-01

    We carry out a series of simulations of G2-type clouds interacting with the black hole at the galactic center, to determine why no large changes in the luminosity of Sgr A * were seen, and to determine the nature of G2. We measure the accretion rate from the gas cloud onto Sgr A * for a range of simulation parameters, such as cloud structure, background structure, background density, grid resolution, and accretion radius. For a broad range of parameters, the amount of cloud material accreted is small relative to the amount of background material accreted. The total accretion rate is not significantly effected for at least 30 yr after periapsis. We find that reproducing observations of G2 likely requires two components for the object: an extended, cold gas cloud responsible for the Br- γ emission, and a compact core or dusty stellar object dominating the bolometric luminosity. In simulations, the bolometric and X-ray luminosity have a peak lasting from about one year before to one year after periapsis, a feature not detected in observations. Our simulated Br- γ emission is largely consistent with observations leading up to periapsis, with a slight increase in luminosity and a large increase in the FWHM of the line velocity. All emission from a gaseous component of G2 should fade rapidly after periapsis and be undetectable after one year, due to shock heating and expansion of the cloud. Any remaining emission should be from the compact component of G2.

  10. GRMHD Simulations of Visibility Amplitude Variability for Event Horizon Telescope Images of Sgr A*

    Science.gov (United States)

    Medeiros, Lia; Chan, Chi-kwan; Özel, Feryal; Psaltis, Dimitrios; Kim, Junhan; Marrone, Daniel P.; Sa¸dowski, Aleksander

    2018-04-01

    The Event Horizon Telescope will generate horizon scale images of the black hole in the center of the Milky Way, Sgr A*. Image reconstruction using interferometric visibilities rests on the assumption of a stationary image. We explore the limitations of this assumption using high-cadence disk- and jet-dominated GRMHD simulations of Sgr A*. We also employ analytic models that capture the basic characteristics of the images to understand the origin of the variability in the simulated visibility amplitudes. We find that, in all simulations, the visibility amplitudes for baselines oriented parallel and perpendicular to the spin axis of the black hole follow general trends that do not depend strongly on accretion-flow properties. This suggests that fitting Event Horizon Telescope observations with simple geometric models may lead to a reasonably accurate determination of the orientation of the black hole on the plane of the sky. However, in the disk-dominated models, the locations and depths of the minima in the visibility amplitudes are highly variable and are not related simply to the size of the black hole shadow. This suggests that using time-independent models to infer additional black hole parameters, such as the shadow size or the spin magnitude, will be severely affected by the variability of the accretion flow.

  11. PARTICLE ACCELERATION AND THE ORIGIN OF X-RAY FLARES IN GRMHD SIMULATIONS OF SGR A*

    Energy Technology Data Exchange (ETDEWEB)

    Ball, David; Özel, Feryal; Psaltis, Dimitrios; Chan, Chi-kwan [Steward Observatory and Department of Astronomy, University of Arizona (United States)

    2016-07-20

    Significant X-ray variability and flaring has been observed from Sgr A* but is poorly understood from a theoretical standpoint. We perform general relativistic magnetohydrodynamic simulations that take into account a population of non-thermal electrons with energy distributions and injection rates that are motivated by PIC simulations of magnetic reconnection. We explore the effects of including these non-thermal electrons on the predicted broadband variability of Sgr A* and find that X-ray variability is a generic result of localizing non-thermal electrons to highly magnetized regions, where particles are likely to be accelerated via magnetic reconnection. The proximity of these high-field regions to the event horizon forms a natural connection between IR and X-ray variability and accounts for the rapid timescales associated with the X-ray flares. The qualitative nature of this variability is consistent with observations, producing X-ray flares that are always coincident with IR flares, but not vice versa, i.e., there are a number of IR flares without X-ray counterparts.

  12. HOW SOFT GAMMA REPEATERS MIGHT MAKE FAST RADIO BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Katz, J. I., E-mail: katz@wuphys.wustl.edu [Department of Physics and McDonnell Center for the Space Sciences, Washington University, St. Louis, Mo. 63130 (United States)

    2016-08-01

    There are several phenomenological similarities between soft gamma repeaters (SGRs) and fast radio bursts (FRBs), including duty factors, timescales, and repetition. The sudden release of magnetic energy in a neutron star magnetosphere, as in popular models of SGRs, can meet the energy requirements of FRBs, but requires both the presence of magnetospheric plasma, in order for dissipation to occur in a transparent region, and a mechanism for releasing much of that energy quickly. FRB sources and SGRs are distinguished by long-lived (up to thousands of years) current-carrying coronal arches remaining from the formation of the young neutron star, and their decay ends the phase of SGR/AXP/FRB activity even though “magnetar” fields may persist. Runaway increases in resistance when the current density exceeds a threshold, releases magnetostatic energy in a sudden burst, and produces high brightness GHz emission of FRB by a coherent process. SGRs are produced when released energy thermalizes as an equlibrium pair plasma. The failures of some alternative FRB models and the non-detection of SGR 1806-20 at radio frequencies are discussed in the appendices.

  13. HOW SOFT GAMMA REPEATERS MIGHT MAKE FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Katz, J. I.

    2016-01-01

    There are several phenomenological similarities between soft gamma repeaters (SGRs) and fast radio bursts (FRBs), including duty factors, timescales, and repetition. The sudden release of magnetic energy in a neutron star magnetosphere, as in popular models of SGRs, can meet the energy requirements of FRBs, but requires both the presence of magnetospheric plasma, in order for dissipation to occur in a transparent region, and a mechanism for releasing much of that energy quickly. FRB sources and SGRs are distinguished by long-lived (up to thousands of years) current-carrying coronal arches remaining from the formation of the young neutron star, and their decay ends the phase of SGR/AXP/FRB activity even though “magnetar” fields may persist. Runaway increases in resistance when the current density exceeds a threshold, releases magnetostatic energy in a sudden burst, and produces high brightness GHz emission of FRB by a coherent process. SGRs are produced when released energy thermalizes as an equlibrium pair plasma. The failures of some alternative FRB models and the non-detection of SGR 1806-20 at radio frequencies are discussed in the appendices.

  14. High Resolution Optical Spectroscopy of the Classical Nova V5668 Sgr Showing the Presence of Lithium

    Science.gov (United States)

    Wagner, R. Mark; Woodward, Charles E.; Starrfield, Sumner; Ilyin, Ilya; Strassmeier, Klaus

    2018-01-01

    The classical nova (CN) V5668 Sgr was discovered on 2015 March 15.634 and initial optical spectra implied it was an Fe II-class CN. We obtained high resolution optical spectroscopy on 30 nights between 2015 April 3 and 2016 June 5 with the 2 x 8.4 m Large Binocular Telescope (LBT) and the 1.8 m Vatican Advanced Technology Telescope (VATT) using the Potsdam Echelle Polarimetric Spectroscopic Instrument (PEPSI). The spectra cover all or part of the 3830-9065 Å spectral region at a spectral resolution of up to 270,000 (1 km/s); the highest resolution currently available on any 8-10 m class telescope. The early spectra are dominated by emission lines of the Balmer and Paschen series of hydrogen, Fe II, Ca II, and Na I with P Cyg-type line profiles as well as emission lines of [O I]. Numerous interstellar lines and bands are readily apparent at high spectral resolution. The permitted line profiles show complex and dramatic variations in the multi-component P Cyg-type line profiles with time. We detect a weak blue-shifted absorption line at a velocity consistent with Li I 6708 Å when compared with the line profiles of Hβ, Fe II 5169 Å, and Na I D. This line is present in spectra obtained on 7 of 8 consecutive nights up to day 21 of the outburst; but absent on day 42 when it is evident that the ionization of the ejecta has significantly increased. The equivalent width of the line converted to a column density, and the resulting mass fraction, imply a significant enrichment of 7Li in the ejecta. 7Li is produced by the decay of unstable 7Be created during the thermonuclear runaway. The discovery of the resonance lines of 7Be II in the optical spectra of the recent CNe V339 Del, V2944 Oph, and V5668 Sgr by Tajitsu et al. (2016) and its subsequent decay to 7Li (half life of 53 days) suggests a significant enrichment of 7Li in the Galaxy from CNe is possible. Our observations of the Li I 6708 Å line in the early optical spectra of V5668 Sgr mark the second direct

  15. SGR J1550-5418 BURSTS DETECTED WITH THE FERMI GAMMA-RAY BURST MONITOR DURING ITS MOST PROLIFIC ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Van der Horst, A. J.; Finger, M. H. [Universities Space Research Association, NSSTC, Huntsville, AL 35805 (United States); Kouveliotou, C. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Gorgone, N. M. [Connecticut College, New London, CT 06320 (United States); Kaneko, Y.; Goegues, E.; Lin, L. [Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul 34956 (Turkey); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Guiriec, S.; Bhat, P. N.; Chaplin, V. L.; Goldstein, A. [University of Alabama, Huntsville, CSPAR, Huntsville, AL 35805 (United States); Granot, J. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Watts, A. L. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Bissaldi, E.; Gruber, D. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, 85748 Garching (Germany); Gehrels, N.; Harding, A. K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gibby, M. H.; Giles, M. M., E-mail: A.J.VanDerHorst@uva.nl [Jacobs Technology, Inc., Huntsville, AL (United States); and others

    2012-04-20

    We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in 2009 January, resulting in the largest uniform sample of temporal and spectral properties of SGR J1550-5418 bursts. We have used the combination of broadband and high time-resolution data provided with GBM to perform statistical studies for the source properties. We determine the durations, emission times, duty cycles, and rise times for all bursts, and find that they are typical of SGR bursts. We explore various models in our spectral analysis, and conclude that the spectra of SGR J1550-5418 bursts in the 8-200 keV band are equally well described by optically thin thermal bremsstrahlung (OTTB), a power law (PL) with an exponential cutoff (Comptonized model), and two blackbody (BB) functions (BB+BB). In the spectral fits with the Comptonized model, we find a mean PL index of -0.92, close to the OTTB index of -1. We show that there is an anti-correlation between the Comptonized E{sub peak} and the burst fluence and average flux. For the BB+BB fits, we find that the fluences and emission areas of the two BB functions are correlated. The low-temperature BB has an emission area comparable to the neutron star surface area, independent of the temperature, while the high-temperature BB has a much smaller area and shows an anti-correlation between emission area and temperature. We compare the properties of these bursts with bursts observed from other SGR sources during extreme activations, and discuss the implications of our results in the context of magnetar burst models.

  16. SGR J1550-5418 Bursts Detected with the Fermi Gamma-Ray Burst Monitor during Its Most Prolific Activity

    Science.gov (United States)

    vanderHorst, A. J.; Kouveliotou, C.; Gorgone, N. M.; Kaneko, Y.; Baring, M. G.; Guiriec, S.; Gogus, E,; Granot, J.; Watts, A. L.; Lin, L.; hide

    2012-01-01

    We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in 2009 January, resulting in the largest uniform sample of temporal and spectral properties of SGR J1550-5418 bursts. We have used the combination of broadband and high time-resolution data provided with GBM to perform statistical studies for the source properties.We determine the durations, emission times, duty cycles, and rise times for all bursts, and find that they are typical of SGR bursts. We explore various models in our spectral analysis, and conclude that the spectra of SGR J15505418 bursts in the 8-200 keV band are equally well described by optically thin thermal bremsstrahlung (OTTB), a power law (PL) with an exponential cutoff (Comptonized model), and two blackbody (BB) functions (BB+BB). In the spectral fits with the Comptonized model, we find a mean PL index of -0.92, close to the OTTB index of -1. We show that there is an anti-correlation between the Comptonized E(sub peak) and the burst fluence and average flux. For the BB+BBfits, we find that the fluences and emission areas of the two BB functions are correlated. The low-temperature BB has an emission area comparable to the neutron star surface area, independent of the temperature, while the high temperature BB has a much smaller area and shows an anti-correlation between emission area and temperature.We compare the properties of these bursts with bursts observed from other SGR sources during extreme activations, and discuss the implications of our results in the context of magnetar burst models.

  17. STAYGREEN (CsSGR) is a candidate for the anthracnose (Colletotrichum orbiculare) resistance locus cla in Gy14 cucumber.

    Science.gov (United States)

    Pan, Junsong; Tan, Junyi; Wang, Yuhui; Zheng, Xiangyang; Owens, Ken; Li, Dawei; Li, Yuhong; Weng, Yiqun

    2018-04-21

    Map-based cloning identified a candidate gene for resistance to the anthracnose fungal pathogen Colletotrichum orbiculare in cucumber, which reveals a novel function for the highly conserved STAYGREEN family genes for host disease resistance in plants. Colletotrichum orbiculare is a hemibiotrophic fungal pathogen that causes anthracnose disease in cucumber and other cucurbit crops. No host resistance genes against the anthracnose pathogens have been cloned in crop plants. Here, we reported fine mapping and cloning of a resistance gene to the race 1 anthracnose pathogen in cucumber inbred lines Gy14 and WI 2757. Phenotypic and QTL analysis in multiple populations revealed that a single recessive gene, cla, was underlying anthracnose resistance in both lines, but WI2757 carried an additional minor-effect QTL. Fine mapping using 150 Gy14 × 9930 recombinant inbred lines and 1043 F 2 individuals delimited the cla locus into a 32 kb region in cucumber Chromosome 5 with three predicted genes. Multiple lines of evidence suggested that the cucumber STAYGREEN (CsSGR) gene is a candidate for the anthracnose resistance locus. A single nucleotide mutation in the third exon of CsSGR resulted in the substitution of Glutamine in 9930 to Arginine in Gy14 in CsSGR protein which seems responsible for the differential anthracnose inoculation responses between Gy14 and 9930. Quantitative real-time PCR analysis indicated that CsSGR was significantly upregulated upon anthracnose pathogen inoculation in the susceptible 9930, while its expression was much lower in the resistant Gy14. Investigation of allelic diversities in natural cucumber populations revealed that the resistance allele in almost all improved cultivars or breeding lines of the U.S. origin was derived from PI 197087. This work reveals an unknown function for the highly conserved STAYGREEN (SGR) family genes for host disease resistance in plants.

  18. Polarimetry, photometry and spectroscopy of the intermediate polar V1223 Sgr

    Energy Technology Data Exchange (ETDEWEB)

    Watts, D J; Giles, A B; Greenhill, J G; Hill, K [Tasmania Univ., Sandy Bay (Australia). Dept. of Physics; Bailey, J [Anglo-Australian Observatory, Epping (Australia)

    1985-07-01

    Optical and IR polarization studies of the intermediate polar V1223 Sgr are reported. The optical and IR light curves have assisted in the determination of the photometric period of 0.14 day. The IR flux of the 794-s pulsations is consistent with X-ray heating of a cool atmosphere. The white-dwarf spin period of 746s was not detected. The IR data are consistent with the published fit of a steady state optically thick disc model to the optical and UV continua. No IR excess from the secondary is apparent. High-dispersion spectroscopic observations over half the orbital period show a small radial velocity change accompanied by complex line profile changes. The low mass function implies a low inclination for a main-sequence companion.

  19. DEVIATION OF STELLAR ORBITS FROM TEST PARTICLE TRAJECTORIES AROUND SGr A* DUE TO TIDES AND WINDS

    International Nuclear Information System (INIS)

    Psaltis, Dimitrios; Li, Gongjie; Loeb, Abraham

    2013-01-01

    Monitoring the orbits of stars around Sgr A* offers the possibility of detecting the precession of their orbital planes due to frame dragging, of measuring the spin and quadrupole moment of the black hole, and of testing the no-hair theorem. Here we investigate whether the deviations of stellar orbits from test-particle trajectories due to wind mass loss and tidal dissipation of the orbital energy compromise such measurements. We find that the effects of stellar winds are, in general, negligible. On the other hand, for the most eccentric orbits (e > 0.96) for which an optical interferometer, such as GRAVITY, will detect orbital plane precession due to frame dragging, the tidal dissipation of orbital energy occurs at timescales comparable to the timescale of precession due to the quadrupole moment of the black hole. As a result, this non-conservative effect is a potential source of systematic uncertainty in testing the no-hair theorem with stellar orbits

  20. DEVIATION OF STELLAR ORBITS FROM TEST PARTICLE TRAJECTORIES AROUND SGr A* DUE TO TIDES AND WINDS

    Energy Technology Data Exchange (ETDEWEB)

    Psaltis, Dimitrios [Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Li, Gongjie; Loeb, Abraham, E-mail: dpsaltis@email.arizona.edu, E-mail: gli@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian CfA, 60 Garden Street, Cambridge, MA (United States)

    2013-11-01

    Monitoring the orbits of stars around Sgr A* offers the possibility of detecting the precession of their orbital planes due to frame dragging, of measuring the spin and quadrupole moment of the black hole, and of testing the no-hair theorem. Here we investigate whether the deviations of stellar orbits from test-particle trajectories due to wind mass loss and tidal dissipation of the orbital energy compromise such measurements. We find that the effects of stellar winds are, in general, negligible. On the other hand, for the most eccentric orbits (e > 0.96) for which an optical interferometer, such as GRAVITY, will detect orbital plane precession due to frame dragging, the tidal dissipation of orbital energy occurs at timescales comparable to the timescale of precession due to the quadrupole moment of the black hole. As a result, this non-conservative effect is a potential source of systematic uncertainty in testing the no-hair theorem with stellar orbits.

  1. High-Resolution Spectroscopy of the Hydrogen-Deficient Binary υ Sgr

    Directory of Open Access Journals (Sweden)

    Kipper Tõnu

    2012-09-01

    Full Text Available The high resolution spectra of hydrogen-deficient binary υ Sgr are analyzed. The atmospheric parameters are Teff = 12300±200 K, log g = 2:5±0:5 and ξt = 5 - 15 kms−1 depending on the element. For Fe II ξt = 9:3 ± 0:3 kms−1. Iron is slightly underabundant (-0.2 dex. Nitrogen is overabundant with [N/Fe]ͬ ≈ 1.0, carbon and oxygen are underabundant with [C/Fe] ≈ -1.6 and [O/Fe] ≈ -1.1. The s-process elements Y, Zr and Ba are overabundant about 0.5 dex. Quite large number of emission lines, both permitted and forbidden, originating from low excitation levels of neutral and ionized metals, are identified. Radial velocities of these emission lines indicate that an accretion disk in the system is present.

  2. Intriguing Misalignment Between Radio and Optical Structures in Classical Nova V5668 Sgr

    Science.gov (United States)

    Linford, Justin; Lawrence, Stephen; Chomiuk, Laura; Sokoloski, Jennifer; Nelson, Thomas; Mukai, Koji; Rupen, Michael; Mioduszewski, Amy; van der Horst, Alexander; Kawash, Adam

    2018-01-01

    The mass-loss and particle acceleration mechanism that drive gamma-ray production in classical novae remain largely unknown, but clues can be found in high spatial resolution images. The nova V5668 Sgr erupted in March of 2015 and was detected by the Fermi Gamma-ray Space Telescope approximately 2 days after its eruption. We obtained high-resolution radio images of the ejecta with the Karl G. Jansky Very Large Array (VLA) in December 2016 and January 2017. The VLA images reveal a bipolar morphology, very similar to that seen in V959 Mon. We obtained images of the ejecta with the Hubble Space Telescope (HST) in July 2017 using two narrow-band filters: F657N H-alpha+[N II] and F502N [O III]. The HST images also show a bipolar structure, but the HST structure is not aligned with the VLA structure. We present preliminary results of this multi-wavelength project.

  3. The Giant Flare From SGR 1806-20 And Its Radio Afterglow

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G.B.; /New Mexico U. /NRAO, Socorro; Granot, J.; /KIPAC, Menlo Park

    2006-09-26

    The multi-wavelength observations of the 2004 December 27 Giant Flare (GF) from SGR 1806-20 and its long-lived radio afterglow are briefly reviewed. The GF appears to have been produced by a dramatic reconfiguration of the magnetic field near the surface of the neutron star, possibly accompanied by fractures in the crust. The explosive release of over 10{sup 46} erg (isotropic equivalent) powered a one-sided mildly relativistic outflow. The outflow produced a new expanding radio nebula, that is still visible over a year after the GF. Also considered are the constraints on the total energy in the GF, the energy and mass in the outflow, and on the external density, as well as possible implications for short {gamma}-ray bursts and potential signatures in high energy neutrinos, photons, or cosmic rays. Some possible future observations of this and other GFs are briefly discussed.

  4. Rings of Molecular Line Emission in the Disk Orbiting the Young, Close Binary V4046 Sgr

    Science.gov (United States)

    Dickson-Vandervelde, Dorothy; Kastner, Joel H.; Qi, C.; Forveille, Thierry; Hily-Blant, Pierre; Oberg, Karin; Wilner, David; Andrews, Sean; Gorti, Uma; Rapson, Valerie; Sacco, Germano; Principe, David

    2018-01-01

    We present analysis of a suite of subarcsecond ALMA Band 6 (1.1 - 1.4 mm) molecular line images of the circumbinary, protoplanetary disk orbiting V4046 Sgr. The ~20 Myr-old V4046 Sgr system, which lies a mere ~73 pc from Earth, consists of a close (separation ~10 Rsun) pair of roughly solar-mass stars that are orbited by a gas-rich crcumbinary disk extending to ~350 AU in radius. The ALMA images reveal that the molecules CO and HCN and their isotopologues display centrally peaked surface brightness morphologies, whereas the cyanide group molecules (HC3N, CH3CN), deuterated molecules (DCN, DCO+), hydrocarbons (as traced by C2H), and potential CO ice line tracers (N2H+, and H2CO) appear as a sequence of sharp and diffuse rings of increasing radii. The characteristic sizes of these molecular emission rings, which range from ~25 to >100 AU in radius, are evident in radial emission-line surface brightness profiles extracted from the deprojected disk images. We find that emission from 13CO emission transitions from optically thin to thick within ~50 AU, whereas C18O emission remains optically thin within this radius. We summarize the insight into the physical and chemical processes within this evolved protoplanetary disk that can be obtained from comparisons of the various emission-line morphologies with each other and with that of the continuum (large-grain) emission on size scales of tens of AU.This research is supported by NASA Exoplanets program grant NNX16AB43G to RIT

  5. A note on the puzzling spindown behavior of the Galactic center magnetar SGR J1745–2900

    International Nuclear Information System (INIS)

    Tong, Hao

    2015-01-01

    SGR J1745–2900 is a magnetar near the Galactic center. X-ray observations of this source found a decreasing X-ray luminosity accompanied by an enhanced spindown rate. This negative correlation between X-ray luminosity and spindown rate is hard to understand. The wind braking model of magnetars is employed to explain this puzzling spindown behavior. During the release of magnetic energy of magnetars, a system of particles may be generated. Some of these particles remain trapped in the magnetosphere and may contribute to the X-ray luminosity. The rest of the particles can flow out and take away the rotational energy of the central neutron star. A smaller polar cap angle will cause the decrease of X-ray luminosity and enhanced spindown rate of SGR J1745–2900. This magnetar is shortly expected to have a maximum spindown rate. (paper)

  6. A General Relativistic Null Hypothesis Test with Event Horizon Telescope Observations of the Black Hole Shadow in Sgr A*

    Science.gov (United States)

    Psaltis, Dimitrios; Özel, Feryal; Chan, Chi-Kwan; Marrone, Daniel P.

    2015-12-01

    The half opening angle of a Kerr black hole shadow is always equal to (5 ± 0.2)GM/Dc2, where M is the mass of the black hole and D is its distance from the Earth. Therefore, measuring the size of a shadow and verifying whether it is within this 4% range constitutes a null hypothesis test of general relativity. We show that the black hole in the center of the Milky Way, Sgr A*, is the optimal target for performing this test with upcoming observations using the Event Horizon Telescope (EHT). We use the results of optical/IR monitoring of stellar orbits to show that the mass-to-distance ratio for Sgr A* is already known to an accuracy of ∼4%. We investigate our prior knowledge of the properties of the scattering screen between Sgr A* and the Earth, the effects of which will need to be corrected for in order for the black hole shadow to appear sharp against the background emission. Finally, we explore an edge detection scheme for interferometric data and a pattern matching algorithm based on the Hough/Radon transform and demonstrate that the shadow of the black hole at 1.3 mm can be localized, in principle, to within ∼9%. All these results suggest that our prior knowledge of the properties of the black hole, of scattering broadening, and of the accretion flow can only limit this general relativistic null hypothesis test with EHT observations of Sgr A* to ≲10%.

  7. Optical Spectroscopy of the Classical Novae V339 Del (2013) and V5668 Sgr (2015 No. 2)

    Science.gov (United States)

    Wagner, R. Mark; Woodward, Charles E.; Starrfield, Sumner; Ilyin, Ilya; Strassmeier, Klaus G.; Page, Kim; Osborne, Julian P.; Beardmore, Andrew P.

    2016-01-01

    We report the results of optical spectroscopy of the gamma-ray classical novae V339 Del (2013) and V5668 Sgr (PNV J18365700-2855420/Nova Sgr 2015 No. 2) supplemented by UV and X-ray observations obtained with Swift. Our spectra were obtained with the Steward Observatory Bok 2.3 m telescope (+B&C), the MDM 2.4 m Hiltner telescope (+OSMOS), the 6.5 m MMT (+BlueChannel), and the 2 x 8.4 m Large Binocular Telescope (+MODS1 and PEPSI) between 2013 August and 2015 September. The PEPSI spectra cover all or part of the 384-907 nm spectral region at a resolution of up to 270,000 (1 km/s). This is the highest resolution available on any 8-10 m class telescope. V339 Del was discovered on 2015 August 14.58 by Itagaki at V about 6.8. This nova reached a peak magnitude of about 4.3 making it one of the brightest novae of this century. Because of its exceptional brightness it has been observed at a variety of wavelengths and by a host of observatories both on the ground and in space. V5668 Sgr was discovered on 2015 March 15.634 by Seach at a magnitude of 6.0. It subsequently reached a maximum brightness of about 4.0 in late March. High resolution PEPSI spectra obtained in early April show dramatic variations in the multi-component P Cygni-type line profiles. V5668 Sgr was observed to form dust in June thereafter fading to about 13th magnitude. Our recent observations show that it has now evolved into the nebular phase. SS acknowledges partial support from NSF and NASA grants to ASU. CEW acknowledges support from NASA.

  8. Radio emission from Sgr A*: pulsar transits through the accretion disc

    Science.gov (United States)

    Christie, I. M.; Petropoulou, M.; Mimica, P.; Giannios, D.

    2017-06-01

    Radiatively inefficient accretion flow models have been shown to accurately account for the spectrum and luminosity observed from Sgr A* in the X-ray regime down to mm wavelengths. However, observations at a few GHz cannot be explained by thermal electrons alone but require the presence of an additional non-thermal particle population. Here, we propose a model for the origin of such a population in the accretion flow via means of a pulsar orbiting the supermassive black hole in our Galaxy. Interactions between the relativistic pulsar wind with the disc lead to the formation of a bow shock in the wind. During the pulsar's transit through the accretion disc, relativistic pairs, accelerated at the shock front, are injected into the disc. The radio-emitting particles are long lived and remain within the disc long after the pulsar's transit. Periodic pulsar transits through the disc result in regular injection episodes of non-thermal particles. We show that for a pulsar with spin-down luminosity Lsd ˜ 3 × 1035 erg s-1 and a wind Lorentz factor of γw ˜ 104 a quasi-steady synchrotron emission is established with luminosities in the 1-10 GHz range comparable to the observed one.

  9. X-Ray Observations of Magnetar SGR 0501+4516 from Outburst to Quiescence

    Science.gov (United States)

    Mong, Y.-L.; Ng, C.-Y.

    2018-01-01

    Magnetars are neutron stars having extreme magnetic field strengths. Study of their emission properties in quiescent state can help understand effects of a strong magnetic field on neutron stars. SGR 0501+4516 is a magnetar that was discovered in 2008 during an outburst, which has recently returned to quiescence. We report its spectral and timing properties measured with new and archival observations from the Chandra X-ray Observatory, XMM-Newton, and Suzaku. We found that the quiescent spectrum is best fit by a power-law plus two blackbody model, with temperatures of kT low ∼ 0.26 keV and kT high ∼ 0.62 keV. We interpret these two blackbody components as emission from a hotspot and the entire surface. The hotspot radius shrunk from 1.4 km to 0.49 km since the outburst, and there was a significant correlation between its area and the X-ray luminosity, which agrees well with the prediction by the twisted magnetosphere model. We applied the two-temperature spectral model to all magnetars in quiescence and found that it could be a common feature among the population. Moreover, the temperature of the cooler blackbody shows a general trend with the magnetar field strength, which supports the simple scenario of heating by magnetic field decay.

  10. CONFRONTING THE JET MODEL OF Sgr A* WITH THE FARADAY ROTATION MEASURE OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ya-Ping; Yuan, Feng [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Daniel Wang, Q., E-mail: fyuan@shao.ac.cn, E-mail: wqd@astro.umass.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2015-01-01

    Sgr A* is probably the supermassive black hole being investigated most extensively due to its proximity to Earth. Several theoretical models for its steady state emission have been proposed in the past two decades. Both the radiative-inefficient accretion flow and the jet model have been shown to well explain the observed spectral energy distribution. The Faraday rotation measure (RM) has been unambiguously measured at the submillimeter wavelength, but it has only been tested against the accretion flow model. Here we first calculate the RM based on the jet model and find that the predicted value is two orders of magnitude lower than the measured value. We then include an additional contribution from the accretion flow in front of the jet and show that the measured RM may be reconciled with the model under some tight constraints. The main constraint is that the inclination angle should be greater than ∼73°. However, this requirement is not consistent with an existing observational estimate of the inclination angle.

  11. The Sleeping Monster: NuSTAR Observations of SGR 1806-20, 11 Years After the Giant Flare

    Science.gov (United States)

    Younes, George; Baring, Matthew G.; Kouveliotou, Chryssa; Harding, Alice; Donovan, Sophia; Göğüş, Ersin; Kaspi, Victoria; Granot, Jonathan

    2017-12-01

    We report the analysis of five Nuclear Spectroscopic Telescope Array (NuSTAR) observations of SGR 1806-20 spread over a year from 2015 April to 2016 April, more than 11 years following its giant flare (GF) of 2004. The source spin frequency during the NuSTAR observations follows a linear trend with a frequency derivative \\dot{ν }=(-1.25+/- 0.03)× {10}-12 Hz s-1, implying a surface dipole equatorial magnetic field B≈ 7.7× {10}14 G. Thus, SGR 1806-20 has finally returned to its historical minimum torque level measured between 1993 and 1998. The source showed strong timing noise for at least 12 years starting in 2000, with \\dot{ν } increasing one order of magnitude between 2005 and 2011, following its 2004 major bursting episode and GF. SGR 1806-20 has not shown strong transient activity since 2009, and we do not find short bursts in the NuSTAR data. The pulse profile is complex with a pulsed fraction of ˜ 8 % with no indication of energy dependence. The NuSTAR spectra are well fit with an absorbed blackbody, {kT}=0.62+/- 0.06 {keV}, plus a power law, {{Γ }}=1.33+/- 0.03. We find no evidence for variability among the five observations, indicating that SGR 1806-20 has reached a persistent and potentially its quiescent X-ray flux level after its 2004 major bursting episode. Extrapolating the NuSTAR model to lower energies, we find that the 0.5-10 keV flux decay follows an exponential form with a characteristic timescale τ =543+/- 75 days. Interestingly, the NuSTAR flux in this energy range is a factor of ˜2 weaker than the long-term average measured between 1993 and 2003, a behavior also exhibited in SGR 1900+14. We discuss our findings in the context of the magnetar model.

  12. The SGR Multipurpose - Generation IV - Transportable Cogeneration Nuclear Reactor with Innovative Shielding

    International Nuclear Information System (INIS)

    Pahladsingh, R.R.

    2002-01-01

    Deregulation and liberalization are changing the global energy-markets. At the same time innovative technologies are introduced in the electricity industry; often as a requirement from the upcoming Digital Society. Energy solutions for the future are more seen as a mix of energy-sources for generation-, transmission- and distribution energy-services. The Internet Energy-web based 'Virtual' enterprises are coming up and will gradually change our society. It the fast changing world we have to realize that there will be less time to look for the adequate solutions to anticipate on global developments and the way they will influence our own societies. Global population may reach 9 billion people by 2030; this will put tremendous pressure on energy-, water- and food supply in the global economy. It is time to think about some major issues as described below and come up with the right answers. These are needed on very short term to secure a humane global economic growth and the sustainable global environment. The DOE (Department of Energy - USA) has started the Generation IV initiative for the new generation of nuclear reactors that must lead to much better safety, economics and public acceptance the new reactors. The SGR (Simplified Gas-cooled Reactor) is being proposed as a Generation IV modular nuclear reactor, using graphite pebbles as fuel, whereby an attempt has been made to meet all the DOE requirements, to be used for future nuclear reactors. The focus in this paper is on the changing and emerging global energy-markets and shows some relevant criteria to the nuclear industry and how we can anticipate with improved and new designs towards the coming Digital Society. (author)

  13. First Spectroscopic Studies and Detection in SgrB2 of 13C-DOUBLY Substitued Ethyl Cyanide

    Science.gov (United States)

    Margulès, L.; Motiyenko, R. A.; Guillemin, J.-C.; Müller, Holger S. P.; Belloche, Arnaud

    2015-06-01

    Ethyl cyanide (CH_3CH_2CN) is one of the most abundant complex organic molecules in the interstellar medium firstly detected in OMC-1 and Sgr B2 in 1977. The vibrationally excited states are enough populated under ISM conditions and could be detected. Apart from the deuterated ones, all mono-substituted isotopologues of ethyl cyanide (13C and 15N have been detected in the ISM. The detection of isotopologues in the ISM is important: it can give information about the formation process of complex organic molecules, and it is essential to clean the ISM spectra from the lines of known molecules in order to detect new ones. The 12C/13C ratio found in SgrB2: 20-30 suggests that the doubly 13C could be present in the spectral line survey recently obtained with ALMA (EMoCA), but no spectroscopic studies exist up to now. We measured and analyzed the spectra of the 13C-doubly-substitued species up to 1 THz with the Lille solid-state based spectrometer. The spectroscopic results and and the detection of the doubly 13C species in SgrB2 will be presented. This work was supported by the CNES and the Action sur Projets de l'INSU, PCMI. This work was also done under ANR-13-BS05-0008-02 IMOLABS. Support by the Deutsche Forschungsgemeinschaft via SFB 956, project B3 is acknowledged D.~R.~Johnson, et al., Astrophys.~J. 1977, 218, L370 A.~Belloche, et al., A&A 2013, 559, A47 A.M.~Daly, et al., Astrophys.~J. 2013, 768, 81 K.~Demyk, et al. A&A 2007 466, 255 Margulès, et al. A&A 2009, 493, 565 Belloche et al. 2014, Science, 345, 1584

  14. Functional and RNA-sequencing analysis revealed expression of a novel stay-green gene from Zoysia japonica (ZjSGR caused chlorophyll degradation and accelerated senescence in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Ke Teng

    2016-12-01

    Full Text Available Senescence is not only an important developmental process, but also a responsive regulation to abiotic and biotic stress for plants. Stay-green protein plays crucial roles in plant senescence and chlorophyll degradation. However, the underlying mechanisms were not well studied, particularly in non-model plants. In this study, a novel stay-green gene, ZjSGR, was isolated from Zoysia japonica. Subcellular localization result demonstrated that ZjSGR was localized in the chloroplasts. Quantitative real-time PCR results together with promoter activity determination using transgenic Arabidopsis confirmed that ZjSGR could be induced by darkness, ABA and MeJA. Its expression levels could also be up-regulated by natural senescence, but suppressed by SA treatments. Overexpression of ZjSGR in Arabidopsis resulted in a rapid yellowing phenotype; complementary experiments proved that ZjSGR was a functional homologue of AtNYE1 from Arabidopsis thaliana. Overexpression of ZjSGR accelerated chlorophyll degradation and impaired photosynthesis in Arabidopsis. Transmission electron microscopy observation revealed that overexpression of ZjSGR decomposed the chloroplasts structure. RNA sequencing analysis showed that ZjSGR could play multiple roles in senescence and chlorophyll degradation by regulating hormone signal transduction and the expression of a large number of senescence and environmental stress related genes. Our study provides a better understanding of the roles of SGRs, and new insight into the senescence and chlorophyll degradation mechanisms in plants.

  15. Spitzer/IRAC observations of the variability of Sgr A* and the object G2 at 4.5 μm

    Energy Technology Data Exchange (ETDEWEB)

    Hora, J. L.; Ashby, M. L. N.; Fazio, G. G.; Smith, H. A.; Willner, S. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Witzel, G.; Becklin, E. E.; Ghez, A.; Meyer, L.; Morris, M. R. [University of California, Los Angeles, CA 90095 (United States); Carey, S.; Ingalls, J. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-10-01

    We present the first detection from the Spitzer Space Telescope of 4.5 μm variability from Sgr A*, the emitting source associated with the Milky Way's central black hole. The >23 hr continuous light curve was obtained with the Infrared Array Camera (IRAC) instrument in 2013 December. The result characterizes the variability of Sgr A* prior to the closest approach of the tidally deformed G2 object, a putative infalling gas cloud that orbits close to Sgr A*. The high stellar density at the location of Sgr A* produces a background of ∼250 mJy at 4.5 μm in each pixel with a large pixel-to-pixel gradient, but the light curve for the highly variable Sgr A* source was successfully measured by modeling and removing the variations due to pointing wobble. The observed flux densities range from the noise level of ∼0.7 mJy rms in a 6.4 s measurement to ≳10 mJy. Emission was seen above the noise level ∼34% of the time. The light-curve characteristics, including the flux density distribution and structure function, are consistent with those previously derived at shorter infrared wavelengths. We see no evidence in the light curve for activity attributable to the G2 interaction at the observing epoch, ∼100 days before the expected G2 periapsis passage. The IRAC light curve is more than a factor of two longer than any previous infrared observation, improving constraints on the timescale of the break in the power spectral distribution of Sgr A* flux densities. The data favor the longer of the two previously published values for the timescale.

  16. A QUANTITATIVE TEST OF THE NO-HAIR THEOREM WITH Sgr A* USING STARS, PULSARS, AND THE EVENT HORIZON TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Psaltis, Dimitrios [Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Wex, Norbert; Kramer, Michael [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121, Bonn (Germany)

    2016-02-20

    The black hole in the center of the Milky Way, Sgr A*, has the largest mass-to-distance ratio among all known black holes in the universe. This property makes Sgr A* the optimal target for testing the gravitational no-hair theorem. In the near future, major developments in instrumentation will provide the tools for high-precision studies of its spacetime via observations of relativistic effects in stellar orbits, in the timing of pulsars, and in horizon-scale images of its accretion flow. We explore here the prospect of measuring the properties of the black hole spacetime using all of these three types of observations. We show that the correlated uncertainties in the measurements of the black hole spin and quadrupole moment using the orbits of stars and pulsars are nearly orthogonal to those obtained from measuring the shape and size of the shadow the black hole casts on the surrounding emission. Combining these three types of observations will therefore allow us to assess and quantify systematic biases and uncertainties in each measurement and lead to a highly accurate, quantitative test of the gravitational no-hair theorem.

  17. Probing the Magnetic Field Structure in Sgr A* on Black Hole Horizon Scales with Polarized Radiative Transfer Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Gold, Roman; McKinney, Jonathan C. [Department of Physics and Joint Space-Science Institute, University of Maryland, College Park, MD 20742 (United States); Johnson, Michael D.; Doeleman, Sheperd S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2017-03-10

    Magnetic fields are believed to drive accretion and relativistic jets in black hole accretion systems, but the magnetic field structure that controls these phenomena remains uncertain. We perform general relativistic (GR) polarized radiative transfer of time-dependent three-dimensional GR magnetohydrodynamical simulations to model thermal synchrotron emission from the Galactic Center source Sagittarius A* (Sgr A*). We compare our results to new polarimetry measurements by the Event Horizon Telescope (EHT) and show how polarization in the visibility (Fourier) domain distinguishes and constrains accretion flow models with different magnetic field structures. These include models with small-scale fields in disks driven by the magnetorotational instability as well as models with large-scale ordered fields in magnetically arrested disks. We also consider different electron temperature and jet mass-loading prescriptions that control the brightness of the disk, funnel-wall jet, and Blandford–Znajek-driven funnel jet. Our comparisons between the simulations and observations favor models with ordered magnetic fields near the black hole event horizon in Sgr A*, though both disk- and jet-dominated emission can satisfactorily explain most of the current EHT data. We also discuss how the black hole shadow can be filled-in by jet emission or mimicked by the absence of funnel jet emission. We show that stronger model constraints should be possible with upcoming circular polarization and higher frequency (349 GHz) measurements.

  18. NSV 11749, AN ELDER SIBLING OF THE BORN-AGAIN STARS V605 Aql AND V4334 Sgr?

    Energy Technology Data Exchange (ETDEWEB)

    Miller Bertolami, M. M.; Althaus, L. G. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata (Argentina); Rohrmann, R. D. [Instituto de Ciencias Astronomicas, de la Tierra y del Espacio, CONICET, Av. de Espana 1512 (Sur) CC 49, 5400 San Juan (Argentina); Granada, A., E-mail: mmiller@fcaglp.unlp.edu.ar [Observatoire Astronomique de l' Universite de Geneve 51, Chemin des Maillettes, CH-1290, Sauverny (Switzerland)

    2011-12-20

    We argue that NSV 11749, an eruption observed in the early twentieth century, was a rare event known as 'very late thermal pulse' (VLTP). To support our argument we compare the light curve of NSV 11749 with those of the two bona fide VLTP objects known to date, V4334 Sgr and V605 Aql, and with those predicted by state-of-the-art stellar evolution models. Next, we explore the INT Photometric H-Alpha Survey (IPHAS) and Two Micron All Sky Survey (2MASS) catalogs for possible counterparts of the eruption. Our analysis shows that the VLTP scenario outperforms all other proposed scenarios as an explanation of NSV 11749. We identify an IPHAS/2MASS source at the eruption location of NSV 11749. The derived colors suggest that the object is not enshrouded in a thick dust shell as V605 Aql and V4334 Sgr. Also, the absence of an apparent planetary nebula at the eruption location suggests differences with known VLTP objects which might be linked to the intensity of the eruption and the mass of the object. Further exploration of this source and scenario seems desirable. If NSV 11749 was a born-again star, it would be the third event of its kind to have been observed and will strongly help us to increase our understanding of the later stages of stellar evolution and violent reactive convective burning.

  19. NSV 11749, AN ELDER SIBLING OF THE BORN-AGAIN STARS V605 Aql AND V4334 Sgr?

    International Nuclear Information System (INIS)

    Miller Bertolami, M. M.; Althaus, L. G.; Rohrmann, R. D.; Granada, A.

    2011-01-01

    We argue that NSV 11749, an eruption observed in the early twentieth century, was a rare event known as 'very late thermal pulse' (VLTP). To support our argument we compare the light curve of NSV 11749 with those of the two bona fide VLTP objects known to date, V4334 Sgr and V605 Aql, and with those predicted by state-of-the-art stellar evolution models. Next, we explore the INT Photometric H-Alpha Survey (IPHAS) and Two Micron All Sky Survey (2MASS) catalogs for possible counterparts of the eruption. Our analysis shows that the VLTP scenario outperforms all other proposed scenarios as an explanation of NSV 11749. We identify an IPHAS/2MASS source at the eruption location of NSV 11749. The derived colors suggest that the object is not enshrouded in a thick dust shell as V605 Aql and V4334 Sgr. Also, the absence of an apparent planetary nebula at the eruption location suggests differences with known VLTP objects which might be linked to the intensity of the eruption and the mass of the object. Further exploration of this source and scenario seems desirable. If NSV 11749 was a born-again star, it would be the third event of its kind to have been observed and will strongly help us to increase our understanding of the later stages of stellar evolution and violent reactive convective burning.

  20. A formal method for identifying distinct states of variability in time-varying sources: SGR A* as an example

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, L.; Witzel, G.; Ghez, A. M. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Longstaff, F. A. [UCLA Anderson School of Management, University of California, Los Angeles, CA 90095-1481 (United States)

    2014-08-10

    Continuously time variable sources are often characterized by their power spectral density and flux distribution. These quantities can undergo dramatic changes over time if the underlying physical processes change. However, some changes can be subtle and not distinguishable using standard statistical approaches. Here, we report a methodology that aims to identify distinct but similar states of time variability. We apply this method to the Galactic supermassive black hole, where 2.2 μm flux is observed from a source associated with Sgr A* and where two distinct states have recently been suggested. Our approach is taken from mathematical finance and works with conditional flux density distributions that depend on the previous flux value. The discrete, unobserved (hidden) state variable is modeled as a stochastic process and the transition probabilities are inferred from the flux density time series. Using the most comprehensive data set to date, in which all Keck and a majority of the publicly available Very Large Telescope data have been merged, we show that Sgr A* is sufficiently described by a single intrinsic state. However, the observed flux densities exhibit two states: noise dominated and source dominated. Our methodology reported here will prove extremely useful to assess the effects of the putative gas cloud G2 that is on its way toward the black hole and might create a new state of variability.

  1. Revisiting the TALE repeat.

    Science.gov (United States)

    Deng, Dong; Yan, Chuangye; Wu, Jianping; Pan, Xiaojing; Yan, Nieng

    2014-04-01

    Transcription activator-like (TAL) effectors specifically bind to double stranded (ds) DNA through a central domain of tandem repeats. Each TAL effector (TALE) repeat comprises 33-35 amino acids and recognizes one specific DNA base through a highly variable residue at a fixed position in the repeat. Structural studies have revealed the molecular basis of DNA recognition by TALE repeats. Examination of the overall structure reveals that the basic building block of TALE protein, namely a helical hairpin, is one-helix shifted from the previously defined TALE motif. Here we wish to suggest a structure-based re-demarcation of the TALE repeat which starts with the residues that bind to the DNA backbone phosphate and concludes with the base-recognition hyper-variable residue. This new numbering system is consistent with the α-solenoid superfamily to which TALE belongs, and reflects the structural integrity of TAL effectors. In addition, it confers integral number of TALE repeats that matches the number of bound DNA bases. We then present fifteen crystal structures of engineered dHax3 variants in complex with target DNA molecules, which elucidate the structural basis for the recognition of bases adenine (A) and guanine (G) by reported or uncharacterized TALE codes. Finally, we analyzed the sequence-structure correlation of the amino acid residues within a TALE repeat. The structural analyses reported here may advance the mechanistic understanding of TALE proteins and facilitate the design of TALEN with improved affinity and specificity.

  2. Reconfigurable multiport EPON repeater

    Science.gov (United States)

    Oishi, Masayuki; Inohara, Ryo; Agata, Akira; Horiuchi, Yukio

    2009-11-01

    An extended reach EPON repeater is one of the solutions to effectively expand FTTH service areas. In this paper, we propose a reconfigurable multi-port EPON repeater for effective accommodation of multiple ODNs with a single OLT line card. The proposed repeater, which has multi-ports in both OLT and ODN sides, consists of TRs, BTRs with the CDR function and a reconfigurable electrical matrix switch, can accommodate multiple ODNs to a single OLT line card by controlling the connection of the matrix switch. Although conventional EPON repeaters require full OLT line cards to accommodate subscribers from the initial installation stage, the proposed repeater can dramatically reduce the number of required line cards especially when the number of subscribers is less than a half of the maximum registerable users per OLT. Numerical calculation results show that the extended reach EPON system with the proposed EPON repeater can save 17.5% of the initial installation cost compared with a conventional repeater, and can be less expensive than conventional systems up to the maximum subscribers especially when the percentage of ODNs in lightly-populated areas is higher.

  3. Quantum repeated games revisited

    International Nuclear Information System (INIS)

    Frąckiewicz, Piotr

    2012-01-01

    We present a scheme for playing quantum repeated 2 × 2 games based on Marinatto and Weber’s approach to quantum games. As a potential application, we study the twice repeated Prisoner’s Dilemma game. We show that results not available in the classical game can be obtained when the game is played in the quantum way. Before we present our idea, we comment on the previous scheme of playing quantum repeated games proposed by Iqbal and Toor. We point out the drawbacks that make their results unacceptable. (paper)

  4. Repeat migration and disappointment.

    Science.gov (United States)

    Grant, E K; Vanderkamp, J

    1986-01-01

    This article investigates the determinants of repeat migration among the 44 regions of Canada, using information from a large micro-database which spans the period 1968 to 1971. The explanation of repeat migration probabilities is a difficult task, and this attempt is only partly successful. May of the explanatory variables are not significant, and the overall explanatory power of the equations is not high. In the area of personal characteristics, the variables related to age, sex, and marital status are generally significant and with expected signs. The distance variable has a strongly positive effect on onward move probabilities. Variables related to prior migration experience have an important impact that differs between return and onward probabilities. In particular, the occurrence of prior moves has a striking effect on the probability of onward migration. The variable representing disappointment, or relative success of the initial move, plays a significant role in explaining repeat migration probabilities. The disappointment variable represents the ratio of actural versus expected wage income in the year after the initial move, and its effect on both repeat migration probabilities is always negative and almost always highly significant. The repeat probabilities diminish after a year's stay in the destination region, but disappointment in the most recent year still has a bearing on the delayed repeat probabilities. While the quantitative impact of the disappointment variable is not large, it is difficult to draw comparisons since similar estimates are not available elsewhere.

  5. High-energy x-ray detection of G359.89–0.08 (SGR A–E): magnetic flux tube emission powered by cosmic rays?

    DEFF Research Database (Denmark)

    Zhang, Shuo; Hailey, Charles J.; Baganoff, Frederick K.

    2014-01-01

    of 8.0 kpc. Based on theoretical predictions and observations, we conclude that Sgr A–E is unlikely to be a pulsar wind nebula (PWN) or supernova remnant-molecular cloud (SNR-MC) interaction, as previously hypothesized. Instead, the emission could be due to a magnetic flux tube which traps Te...

  6. Reversal of infall in SgrB2(M) revealed by Herschel/HIFI observations of HCN lines at THz frequencies

    NARCIS (Netherlands)

    Rolffs, R.; Schilke, P.; Comito, C.; Bergin, E. A.; van der Tak, F. F. S.; Lis, D. C.; Qin, S.-L.; Menten, K. M.; Guesten, R.; Bell, T. A.; Blake, G.A.; Caux, E.; Ceccarelli, C.; Cernicharo, J.; Crockett, N. R.; Daniel, F.; Dubernet, M. -L.; Emprechtinger, M.; Encrenaz, P.; Gerin, M.; Giesen, T. F.; Goicoechea, J. R.; Goldsmith, P. F.; Gupta, H.; Herbst, E.; Joblin, C.; Johnstone, D.; Langer, W. D.; Latter, W. D.; Lord, S. D.; Maret, S.; Martin, P. G.; Melnick, G. J.; Morris, P.; Mueller, H. S. P.; Murphy, J. A.; Ossenkopf, V.; Pearson, J. C.; Perault, M.; Phillips, T. G.; Plume, R.; Schlemmer, S.; Stutzki, J.; Trappe, N.; Vastel, C.; Wang, S.; Yorke, H. W.; Yu, S.; Zmuidzinas, J.; Diez-Gonzalez, M. C.; Bachiller, R.; Martin-Pintado, J.; Baechtold, W.; Olberg, M.; Nordh, L. H.; Gill, J. J.; Chattopadhyay, G.

    2010-01-01

    Aims. To investigate the accretion and feedback processes in massive star formation, we analyze the shapes of emission lines from hot molecular cores, whose asymmetries trace infall and expansion motions. Methods. The high-mass star forming region SgrB2(M) was observed with Herschel/HIFI (HEXOS key

  7. High-energy X-rays from J174545.5-285829, the cannonball: a candidate pulsar wind nebula associated with SGR a east

    DEFF Research Database (Denmark)

    Nynka, Melania; Hailey, Charles J.; Mori, Kaya

    2013-01-01

    V) = 1.3 × 1034 erg s-1 . The spectral and spatial results derived from X-ray and radio data strongly suggest a runaway neutron star born in the Sgr A East supernova event. We do not find any pulsed signal from the Cannonball. The NuSTAR observations allow us to deduce the PWN magnetic field and show...

  8. BURST FLUENCE DISTRIBUTIONS OF SOFT GAMMA REPEATERS 1806–20 AND 1900+14 IN THE ROSSI X-RAY TIMING EXPLORER PCA ERA

    International Nuclear Information System (INIS)

    Prieskorn, Zachary; Kaaret, Philip

    2012-01-01

    We study the fluence distributions of over 3040 bursts from SGR 1806–20 and over 1963 bursts from SGR 1900+14 using the complete set of observations available from the Rossi X-Ray Timing Explorer/Proportional Counter Array through 2011 March. Cumulative event distributions are presented for both sources and are fitted with single and broken power laws as well as an exponential cutoff. The distributions are best fitted by a broken power law with exponential cutoff; however the statistical significance of the cutoff is not high and the upper portion of the broken power law can be explained as the expected number of false bursts due to random noise fluctuations. Event distributions are also examined in high and low burst rate regimes and power-law indices are found to be consistent, independent of the burst rate. The contribution function of the event fluence is calculated. This distribution shows that the energy released in the soft gamma repeater (SGR) bursts is dominated by the most powerful events for both sources. The power-law nature of these distributions combined with the dominant energy dissipation of the system occurring in the large, less frequent bursts is indicative of a self-organized critical system, as suggested by Goğus et al. in 1999.

  9. HERSCHEL* FAR-INFRARED SPECTROSCOPY OF THE GALACTIC CENTER. HOT MOLECULAR GAS: SHOCKS VERSUS RADIATION NEAR Sgr A

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, Javier R.; Etxaluze, M.; Cernicharo, J.; Bell, T. A. [Departamento de Astrofisica, Centro de Astrobiologia, CSIC-INTA, Carretera de Ajalvir, Km 4, Torrejon de Ardoz, E-28850 Madrid (Spain); Gerin, M.; De Luca, M.; Encrenaz, P. [LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole Normale Superieure (France); Neufeld, D. A.; Indriolo, N. [Johns Hopkins University, Baltimore, MD 21218 (United States); Contursi, A. [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Postfach 1312, D-85741 Garching (Germany); Lis, D. C. [California Institute of Technology, Pasadena, CA 91125 (United States); Polehampton, E. T. [RAL Space, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Sonnentrucker, P., E-mail: jr.goicoechea@cab.inta-csic.es [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2013-05-20

    We present a {approx}52-671 {mu}m spectral scan toward Sgr A* taken with the PACS and SPIRE spectrometers on board Herschel. The achieved angular resolution allows us to separate, for the first time at far-IR wavelengths, the emission toward the central cavity (gas in the inner central parsec of the galaxy) from that of the surrounding circumnuclear disk. The spectrum toward Sgr A* is dominated by strong [O III], [O I], [C II], [N III], [N II], and [C I] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by UV photons from the central stellar cluster. In addition, rotationally excited lines of {sup 12}CO (from J = 4-3 to 24-23), {sup 13}CO, H{sub 2}O, OH, H{sub 3}O{sup +}, HCO{sup +}, and HCN, as well as ground-state absorption lines of OH{sup +}, H{sub 2}O{sup +}, H{sub 3}O{sup +}, CH{sup +}, H{sub 2}O, OH, HF, CH, and NH are detected. The excitation of the {sup 12}CO ladder is consistent with a hot isothermal component at T{sub k} {approx_equal} 10{sup 3.1} K and n(H{sub 2}) {approx}< 10{sup 4} cm{sup -3}. It is also consistent with a distribution of temperature components at higher density with most CO at T{sub k} {approx}< 300 K. The detected molecular features suggest that, at present, neither very enhanced X-ray nor cosmic-ray fluxes play a dominant role in the heating of the hot molecular gas. The hot CO component (either the bulk of the CO column or just a small fraction depending on the above scenario) results from a combination of UV- and shock-driven heating. If irradiated dense clumps/clouds do not exist, shocks likely dominate the heating of the hot molecular gas. This is consistent with the high-velocity gas detected toward Sgr A*.

  10. NEAR-INFRARED AND X-RAY QUASI-PERIODIC OSCILLATIONS IN NUMERICAL MODELS OF Sgr A*

    International Nuclear Information System (INIS)

    Dolence, Joshua C.; Gammie, Charles F.; Shiokawa, Hotaka; Noble, Scott C.

    2012-01-01

    We report transient quasi-periodic oscillations (QPOs) on minute timescales in relativistic, radiative models of the galactic center source Sgr A*. The QPOs result from nonaxisymmetric m = 1 structure in the accretion flow excited by MHD turbulence. Near-infrared (NIR) and X-ray power spectra show significant peaks at frequencies comparable to the orbital frequency at the innermost stable circular orbit (ISCO) f o . The excess power is associated with inward propagating magnetic filaments inside the ISCO. The amplitudes of the QPOs are sensitive to the electron distribution function. We argue that transient QPOs appear at a range of frequencies in the neighborhood of f o and that the power spectra, averaged over long times, likely show a broad bump near f o rather than distinct, narrow QPO features.

  11. The Pentapeptide Repeat Proteins

    OpenAIRE

    Vetting, Matthew W.; Hegde, Subray S.; Fajardo, J. Eduardo; Fiser, Andras; Roderick, Steven L.; Takiff, Howard E.; Blanchard, John S.

    2006-01-01

    The Pentapeptide Repeat Protein (PRP) family has over 500 members in the prokaryotic and eukaryotic kingdoms. These proteins are composed of, or contain domains composed of, tandemly repeated amino acid sequences with a consensus sequence of [S,T,A,V][D,N][L,F]-[S,T,R][G]. The biochemical function of the vast majority of PRP family members is unknown. The three-dimensional structure of the first member of the PRP family was determined for the fluoroquinolone resistance protein (MfpA) from Myc...

  12. a Look at Nitrile Chemistry in SGR B2(N) Using the Combined Power of the GBT and the VLA

    Science.gov (United States)

    Steber, Amanda; Zaleski, Daniel P.; Seifert, Nathan A.; Neill, Justin; Muckle, Matt; Pate, Brooks; Corby, Joanna F.; Remijan, Anthony

    2014-06-01

    Nitriles form the most prolific family of molecules known in the ISM, and laboratory work shows that radical-driven chemistry can account for the formation of a diverse set of nitrile and imine molecules. Broadband reaction screening of nitrile chemistry in a pulsed discharge nozzle coupled to a chirped-pulse Fourier transform rotational spectrometer has enabled detections of several new interstellar species including E- and Z-ethanimine and E-cyanomethanimine. The detections were made by direct comparisons of laboratory broadband rotational spectra with the Robert C. Byrd Green Bank Telescope (GBT) PRebiotic Interstellar MOlecule Survery (PRIMOS) survey towards Sgr B2(N), the most chemically complex interstellar region known. In order to probe nitrile chemistry in Sgr B2, we targeted low energy rotational transitions in the 18-21 GHz range of several nitriles with the Karl G. Jansky Very Large Array (VLA) at ˜1 arcsecond resolution. The data indicate that most nitriles and nitrile derivatives are co-spatial with shell shaped continuum features thought to be expanding ionization fronts. The CH2CN radical and imine species in particular are NOT associated with the hot core known as the "Large Molecule Heimat", where most large organic molecules are thought to reside. This result suggests radical driven nitrile chemistry may be promoted by near-UV radiation in moderate density regions of molecular clouds, and the data will be useful for evaluating possible formation mechanisms. R.A. Loomis et al. Ap. J. L., 765, (L9), 2013. D.P. Zaleski et al. Ap. J. L., 765, (L10), 2013.

  13. Repeated Causal Decision Making

    Science.gov (United States)

    Hagmayer, York; Meder, Bjorn

    2013-01-01

    Many of our decisions refer to actions that have a causal impact on the external environment. Such actions may not only allow for the mere learning of expected values or utilities but also for acquiring knowledge about the causal structure of our world. We used a repeated decision-making paradigm to examine what kind of knowledge people acquire in…

  14. simple sequence repeat (SSR)

    African Journals Online (AJOL)

    In the present study, 78 mapped simple sequence repeat (SSR) markers representing 11 linkage groups of adzuki bean were evaluated for transferability to mungbean and related Vigna spp. 41 markers amplified characteristic bands in at least one Vigna species. The transferability percentage across the genotypes ranged ...

  15. Testing the nature of the supermassive black hole candidate in SgrA* with light curves and images of hot spots

    International Nuclear Information System (INIS)

    Li, Zilong; Kong, Lingyao; Bambi, Cosimo

    2014-01-01

    General relativity makes clear predictions about the spacetime geometry around black holes. In the near future, new facilities will have the capability to explore the metric around SgrA*, the supermassive black hole candidate at the center of our Galaxy, and to open a new window to test the Kerr black hole hypothesis. In this paper, we compute light curves and images associated with compact emission regions (hot spots) orbiting around Kerr and non-Kerr black holes. We study how the analysis of the properties of the radiation emitted by a hot spot can be used to test the Kerr nature of SgrA*. We find that the sole observation of the hot spot light curve can at most constrain a combination of the black hole spin and of possible deviations from the Kerr solution. This happens because the same orbital frequency around a Kerr black hole can be found for a non-Kerr object with a different spin parameter. Second order corrections in the light curve due to the background geometry are typically too small to be identified. While the observation of the hot spot centroid track can potentially bound possible deviations from the Kerr solution, that is out of reach for the near future for the Very Large Telescope Interferometer instrument GRAVITY. The Kerr black hole hypothesis could really be tested in the case of the discovery of a radio pulsar in a compact orbit around SgrA*. Radio observations of such a pulsar would provide precise estimates of the mass and the spin of SgrA*, and the combination of these measurements (probing the weak field) with the hot spot light curve information (probing the strong field) may constrain/find possible deviations from the Kerr solution with quite good precision.

  16. FLICKERING OF 1.3 cm SOURCES IN SGR B2: TOWARD A SOLUTION TO THE ULTRACOMPACT H II REGION LIFETIME PROBLEM

    Energy Technology Data Exchange (ETDEWEB)

    De Pree, C. G.; Monsrud, A. [Agnes Scott College, 141 East College Avenue, Decatur, GA 30030 (United States); Peters, T. [Institut für Theoretische Physik, Universität Zürich, CH-8057 Zürich (Switzerland); Mac Low, M.-M. [American Museum of Natural History, New York, NY 10024 (United States); Wilner, D. J.; Keto, E. R. [Harvard-Smithsonian CfA, Cambridge, MA 02138 (United States); Goss, W. M. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Galván-Madrid, R. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); Klessen, R. S. [Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany)

    2014-02-01

    Accretion flows onto massive stars must transfer mass so quickly that they are themselves gravitationally unstable, forming dense clumps and filaments. These density perturbations interact with young massive stars, emitting ionizing radiation, alternately exposing and confining their H II regions. As a result, the H II regions are predicted to flicker in flux density over periods of decades to centuries rather than increase monotonically in size as predicted by simple Spitzer solutions. We have recently observed the Sgr B2 region at 1.3 cm with the Very Large Array in its three hybrid configurations (DnC, CnB, and BnA) at a resolution of ∼0.''25. These observations were made to compare in detail with matched continuum observations from 1989. At 0.''25 resolution, Sgr B2 contains 41 ultracompact (UC) H II regions, 6 of which are hypercompact. The new observations of Sgr B2 allow comparison of relative peak flux densities for the H II regions in Sgr B2 over a 23 year time baseline (1989-2012) in one of the most source-rich massive star forming regions in the Milky Way. The new 1.3 cm continuum images indicate that four of the 41 UC H II regions exhibit significant changes in their peak flux density, with one source (K3) dropping in peak flux density, and the other three sources (F10.303, F1, and F3) increasing in peak flux density. The results are consistent with statistical predictions from simulations of high mass star formation, suggesting that they offer a solution to the lifetime problem for UC H II regions.

  17. Testing the nature of the supermassive black hole candidate in SgrA* with light curves and images of hot spots

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zilong; Kong, Lingyao; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China)

    2014-06-01

    General relativity makes clear predictions about the spacetime geometry around black holes. In the near future, new facilities will have the capability to explore the metric around SgrA*, the supermassive black hole candidate at the center of our Galaxy, and to open a new window to test the Kerr black hole hypothesis. In this paper, we compute light curves and images associated with compact emission regions (hot spots) orbiting around Kerr and non-Kerr black holes. We study how the analysis of the properties of the radiation emitted by a hot spot can be used to test the Kerr nature of SgrA*. We find that the sole observation of the hot spot light curve can at most constrain a combination of the black hole spin and of possible deviations from the Kerr solution. This happens because the same orbital frequency around a Kerr black hole can be found for a non-Kerr object with a different spin parameter. Second order corrections in the light curve due to the background geometry are typically too small to be identified. While the observation of the hot spot centroid track can potentially bound possible deviations from the Kerr solution, that is out of reach for the near future for the Very Large Telescope Interferometer instrument GRAVITY. The Kerr black hole hypothesis could really be tested in the case of the discovery of a radio pulsar in a compact orbit around SgrA*. Radio observations of such a pulsar would provide precise estimates of the mass and the spin of SgrA*, and the combination of these measurements (probing the weak field) with the hot spot light curve information (probing the strong field) may constrain/find possible deviations from the Kerr solution with quite good precision.

  18. High-Energy X-rays from J174545.5-285829, the Cannonball: a Candidate Pulsar Wind Nebula Associated with Sgr a East

    Science.gov (United States)

    Nynka, Melania; Hailey, Charles J.; Mori, Kaya; Baganoff, Frederick K.; Bauer, Franz E.; Boggs, Steven E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.; hide

    2013-01-01

    We report the unambiguous detection of non-thermal X-ray emission up to 30 keV from the Cannonball, a few arcsecond long diffuse X-ray feature near the Galactic Center, using the NuSTAR X-ray observatory. The Cannonball is a high-velocity (v(proj) approximately 500 km s(exp -1)) pulsar candidate with a cometary pulsar wind nebula (PWN) located approximately 2' north-east from Sgr A*, just outside the radio shell of the supernova remnant Sagittarius A (Sgr A) East. Its non-thermal X-ray spectrum, measured up to 30 keV, is well characterized by a Gamma is approximately 1.6 power law, typical of a PWN, and has an X-ray luminosity of L(3-30 keV) = 1.3 × 10(exp 34) erg s(exp -1). The spectral and spatial results derived from X-ray and radio data strongly suggest a runaway neutron star born in the Sgr A East supernova event. We do not find any pulsed signal from the Cannonball. The NuSTAR observations allow us to deduce the PWN magnetic field and show that it is consistent with the lower limit obtained from radio observations.

  19. Repeatability of Cryogenic Multilayer Insulation

    Science.gov (United States)

    Johnson, W. L.; Vanderlaan, M.; Wood, J. J.; Rhys, N. O.; Guo, W.; Van Sciver, S.; Chato, D. J.

    2017-12-01

    Due to the variety of requirements across aerospace platforms, and one off projects, the repeatability of cryogenic multilayer insulation (MLI) has never been fully established. The objective of this test program is to provide a more basic understanding of the thermal performance repeatability of MLI systems that are applicable to large scale tanks. There are several different types of repeatability that can be accounted for: these include repeatability between identical blankets, repeatability of installation of the same blanket, and repeatability of a test apparatus. The focus of the work in this report is on the first two types of repeatability. Statistically, repeatability can mean many different things. In simplest form, it refers to the range of performance that a population exhibits and the average of the population. However, as more and more identical components are made (i.e. the population of concern grows), the simple range morphs into a standard deviation from an average performance. Initial repeatability testing on MLI blankets has been completed at Florida State University. Repeatability of five Glenn Research Center (GRC) provided coupons with 25 layers was shown to be +/- 8.4% whereas repeatability of repeatedly installing a single coupon was shown to be +/- 8.0%. A second group of 10 coupons has been fabricated by Yetispace and tested by Florida State University, the repeatability between coupons has been shown to be +/- 15-25%. Based on detailed statistical analysis, the data has been shown to be statistically significant.

  20. FAST VARIABILITY AND MILLIMETER/IR FLARES IN GRMHD MODELS OF Sgr A* FROM STRONG-FIELD GRAVITATIONAL LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chi-kwan; Psaltis, Dimitrios; Özel, Feryal; Marrone, Daniel [Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Medeiros, Lia [Department of Physics, Broida Hall, University of California, Santa Barbara, Santa Barbara, CA 93106 (United States); Sadowski, Aleksander [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Narayan, Ramesh, E-mail: chanc@email.arizona.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-10-20

    We explore the variability properties of long, high-cadence general relativistic magnetohydrodynamic (GRMHD) simulations across the electromagnetic spectrum using an efficient, GPU-based radiative transfer algorithm. We focus on both standard and normal evolution (SANE) and magnetically arrested disk (MAD) simulations with parameters that successfully reproduce the time-averaged spectral properties of Sgr A* and the size of its image at 1.3 mm. We find that the SANE models produce short-timescale variability with amplitudes and power spectra that closely resemble those inferred observationally. In contrast, MAD models generate only slow variability at lower flux levels. Neither set of models shows any X-ray flares, which most likely indicates that additional physics, such as particle acceleration mechanisms, need to be incorporated into the GRMHD simulations to account for them. The SANE models show strong, short-lived millimeter/infrared (IR) flares, with short (≲1 hr) time lags between the millimeter and IR wavelengths, that arise from the combination of short-lived magnetic flux tubes and strong-field gravitational lensing near the horizon. Such events provide a natural explanation for the observed IR flares with no X-ray counterparts.

  1. THE {sup 7}Be ii RESONANCE LINES IN TWO CLASSICAL NOVAE V5668 SGR AND V2944 OPH

    Energy Technology Data Exchange (ETDEWEB)

    Tajitsu, Akito [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, HI 96720 (United States); Sadakane, Kozo [Astronomical Institute, Osaka Kyoiku University, Asahigaoka, Kashiwara, Osaka 582-8582 (Japan); Naito, Hiroyuki [Nayoro Observatory, 157-1 Nisshin, Nayoro, Hokkaido 096-0066 (Japan); Arai, Akira; Kawakita, Hideyo [Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Aoki, Wako, E-mail: tajitsu@naoj.org [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2016-02-20

    We report spectroscopic observations of the resonance lines of singly ionized {sup 7}Be in the blueshifted absorption line systems found in the post-outburst spectra of two classical novae—V5668 Sgr (Nova Sagittarii 2015 No. 2) and V2944 Oph (Nova Ophiuchi 2015). The unstable isotope {sup 7}Be should have been created during the thermonuclear runaway (TNR) of these novae and decayed to form {sup 7}Li within a short period (a half-life of 53.22 days). These confirmations of {sup 7}Be are the second and the third ones following the first case found in V339 Del by Tajitsu et al. The blueshifted absorption line systems in both novae are clearly divided into two velocity components, both of which contain {sup 7}Be. This means that the absorbing gases in both velocity components consist of products of TNR. We estimated the amounts of {sup 7}Be produced during the outbursts of both novae and concluded that significant {sup 7}Li should have been created. These findings strongly suggest that the explosive production of {sup 7}Li via the reaction {sup 3}He(α,γ){sup 7}Be and its  subsequent decay to {sup 7}Li occurs frequently among classical novae and contributes to the process of Galactic Li enrichment.

  2. Repeat Customer Success in Extension

    Science.gov (United States)

    Bess, Melissa M.; Traub, Sarah M.

    2013-01-01

    Four multi-session research-based programs were offered by two Extension specialist in one rural Missouri county. Eleven participants who came to multiple Extension programs could be called "repeat customers." Based on the total number of participants for all four programs, 25% could be deemed as repeat customers. Repeat customers had…

  3. 78 FR 65594 - Vehicular Repeaters

    Science.gov (United States)

    2013-11-01

    ... coordinators estimate the effect on coordination fees? Does the supposed benefit that mobile repeater stations... allow the licensing and operation of vehicular repeater systems and other mobile repeaters by public... email: [email protected] or phone: 202-418- 0530 or TTY: 202-418-0432. For detailed instructions for...

  4. Glucose uptake regulation in E. coli by the small RNA SgrS: comparative analysis of E. coli K-12 (JM109 and MG1655 and E. coli B (BL21

    Directory of Open Access Journals (Sweden)

    Ng Weng-Ian

    2010-09-01

    Full Text Available Abstract Background The effect of high glucose concentration on the transcription levels of the small RNA SgrS and the messenger RNA ptsG, (encoding the glucose transporter IICBGlc, was studied in both E. coli K-12 (MG1655 and JM109 and E. coli B (BL21. It is known that the transcription level of sgrS increases when E. coli K-12 (MG1655 and JM109 is exposed to the non-metabolized glucose alpha methyl glucoside (αMG or when the bacteria with a defective glycolysis pathway is grown in presence of glucose. The increased level of sRNA SgrS reduces the level of the ptsG mRNA and consequently lowers the level of the glucose transporter IICBGlc. The suggested trigger for this action is the accumulation of the corresponding phospho-sugars. Results In the course of the described work, it was found that E. coli B (BL21 and E. coli K-12 (JM109 and MG1655 responded similarly to αMG: both strains increased SgrS transcription and reduced ptsG transcription. However, the two strains reacted differently to high glucose concentration (40 g/L. E. coli B (BL21 reacted by increasing sgrS transcription and reducing ptsG transcription while E. coli K-12 (JM109 and MG1655 did not respond to the high glucose concentration, and, therefore, transcription of sgrS was not detected and ptsG mRNA level was not affected. Conclusions The results suggest that E. coli B (BL21 tolerates high glucose concentration not only by its more efficient central carbon metabolism, but also by controlling the glucose transport into the cells regulated by the sRNA SgrS, which may suggest a way to control glucose consumption and increase its efficient utilization.

  5. Many faces of compact objects: distance, optical extinction and multi-wavelength behaviour

    International Nuclear Information System (INIS)

    Corbel, Stephane

    1999-01-01

    This thesis is devoted to a multi-wavelength study of accretion-ejection phenomena around compact stars (black holes and neutron stars). The first part of this manuscript describes problems related to the determination of the distance and the optical extinction to compact objects - fundamental parameters for the evaluation of the energy budget of these systems. To this end, the structure and the dynamics of the Galaxy are studied by observations of the atomic and molecular gas along the line of sight to compact stars. This method leads to the first evaluation of the distance to two Soft Gamma Repeaters: SGR 1806-20 and SGR 1627-41. We then draw some conclusions on the nature of these sources of recurrent gamma-ray bursts. The above method is then applied to two X-ray binaries: Cir X-1 and GX 339-4. In the second part of this thesis, we present a multi-wavelength study of the Galactic black hole candidate GX 339-4. We first discuss the characteristics of the radio emission from GX 339-4. In 1998, GX 339-4 underwent a transition to a soft-high X-ray state and observations in three wavelength regimes (radio, soft and hard X-rays) revealed new patterns of behaviour. This allowed us to constrain the region of origin of the radio emission (a compact jet) in GX 339-4 and allowed a better understanding of the physical coupling between accretion and ejection in GX 339-4. An analogy with the black hole candidate Cyg X-1 is then presented. Finally, these results are discussed in the context of micro-quasars and active galactic nuclei in order to gain a deeper insight into the accretion-ejection coupling around compact objects. (author) [fr

  6. Repeated causal decision making.

    Science.gov (United States)

    Hagmayer, York; Meder, Björn

    2013-01-01

    Many of our decisions refer to actions that have a causal impact on the external environment. Such actions may not only allow for the mere learning of expected values or utilities but also for acquiring knowledge about the causal structure of our world. We used a repeated decision-making paradigm to examine what kind of knowledge people acquire in such situations and how they use their knowledge to adapt to changes in the decision context. Our studies show that decision makers' behavior is strongly contingent on their causal beliefs and that people exploit their causal knowledge to assess the consequences of changes in the decision problem. A high consistency between hypotheses about causal structure, causally expected values, and actual choices was observed. The experiments show that (a) existing causal hypotheses guide the interpretation of decision feedback, (b) consequences of decisions are used to revise existing causal beliefs, and (c) decision makers use the experienced feedback to induce a causal model of the choice situation even when they have no initial causal hypotheses, which (d) enables them to adapt their choices to changes of the decision problem. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

  7. THE POWER OF IMAGING: CONSTRAINING THE PLASMA PROPERTIES OF GRMHD SIMULATIONS USING EHT OBSERVATIONS OF Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chi-Kwan; Psaltis, Dimitrios; Özel, Feryal [Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Narayan, Ramesh [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sadowski, Aleksander, E-mail: chanc@email.arizona.edu [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)

    2015-01-20

    Recent advances in general relativistic magnetohydrodynamic simulations have expanded and improved our understanding of the dynamics of black-hole accretion disks. However, current simulations do not capture the thermodynamics of electrons in the low density accreting plasma. This poses a significant challenge in predicting accretion flow images and spectra from first principles. Because of this, simplified emission models have often been used, with widely different configurations (e.g., disk- versus jet-dominated emission), and were able to account for the observed spectral properties of accreting black holes. Exploring the large parameter space introduced by such models, however, requires significant computational power that exceeds conventional computational facilities. In this paper, we use GRay, a fast graphics processing unit (GPU) based ray-tracing algorithm, on the GPU cluster El Gato, to compute images and spectra for a set of six general relativistic magnetohydrodynamic simulations with different magnetic field configurations and black-hole spins. We also employ two different parametric models for the plasma thermodynamics in each of the simulations. We show that, if only the spectral properties of Sgr A* are used, all 12 models tested here can fit the spectra equally well. However, when combined with the measurement of the image size of the emission using the Event Horizon Telescope, current observations rule out all models with strong funnel emission, because the funnels are typically very extended. Our study shows that images of accretion flows with horizon-scale resolution offer a powerful tool in understanding accretion flows around black holes and their thermodynamic properties.

  8. Expansion of protein domain repeats.

    Directory of Open Access Journals (Sweden)

    Asa K Björklund

    2006-08-01

    Full Text Available Many proteins, especially in eukaryotes, contain tandem repeats of several domains from the same family. These repeats have a variety of binding properties and are involved in protein-protein interactions as well as binding to other ligands such as DNA and RNA. The rapid expansion of protein domain repeats is assumed to have evolved through internal tandem duplications. However, the exact mechanisms behind these tandem duplications are not well-understood. Here, we have studied the evolution, function, protein structure, gene structure, and phylogenetic distribution of domain repeats. For this purpose we have assigned Pfam-A domain families to 24 proteomes with more sensitive domain assignments in the repeat regions. These assignments confirmed previous findings that eukaryotes, and in particular vertebrates, contain a much higher fraction of proteins with repeats compared with prokaryotes. The internal sequence similarity in each protein revealed that the domain repeats are often expanded through duplications of several domains at a time, while the duplication of one domain is less common. Many of the repeats appear to have been duplicated in the middle of the repeat region. This is in strong contrast to the evolution of other proteins that mainly works through additions of single domains at either terminus. Further, we found that some domain families show distinct duplication patterns, e.g., nebulin domains have mainly been expanded with a unit of seven domains at a time, while duplications of other domain families involve varying numbers of domains. Finally, no common mechanism for the expansion of all repeats could be detected. We found that the duplication patterns show no dependence on the size of the domains. Further, repeat expansion in some families can possibly be explained by shuffling of exons. However, exon shuffling could not have created all repeats.

  9. Film repeats in radiology department

    International Nuclear Information System (INIS)

    Suwan, A. Z.; Al-Shakharah, A. I

    1997-01-01

    During a one year period, 4910 radiographs of 55780 films were repeated. The objective of our study was to analyse and to classify the causes in order to minimize the repeats, cut the expenses and to provide optimal radiographs for accurate diagnosis. Analysis of the different factors revealed that, 43.6% of film repeats in our service were due to faults in exposure factors, centering comprises 15.9% of the repeats, while too much collimation was responsible for 7.6% of these repeats. All of which can be decreased by awareness and programmed training of technicians. Film blurring caused by patient motion was also responsible for 4.9% for radiographs reexamination, which can be minimized by detailed explanation to the patient and providing the necessary privacy. Fogging of X-Ray films by improper storage or inadequate handling or processing faults were responsible for 14.5% in repeats in our study. Methods and criteria for proper storage and handling of films were discussed. Recommendation for using modern day-light and laser processor has been high lighted. Artefacts are noticeably high in our cases, due to spinal dresses and frequent usage of precious metals for c osmotic purposes in this part of the world. The repeated films comprise 8.8% of all films We conclude that, the main factor responsible for repeats of up to 81.6% of cases was the technologists, thus emphasizing the importance of adequate training of the technologists. (authors). 15 refs., 9 figs., 1 table

  10. Nifty Nines and Repeating Decimals

    Science.gov (United States)

    Brown, Scott A.

    2016-01-01

    The traditional technique for converting repeating decimals to common fractions can be found in nearly every algebra textbook that has been published, as well as in many precalculus texts. However, students generally encounter repeating decimal numerals earlier than high school when they study rational numbers in prealgebra classes. Therefore, how…

  11. Repeated Prescribed Burning in Aspen

    Science.gov (United States)

    Donald A. Perala

    1974-01-01

    Infrequent burning weather, low flammability of the aspen-hardwood association, and prolific sprouting and seeding of shrubs and hardwoods made repeated dormant season burning a poor tool to convert good site aspen to conifers. Repeat fall burns for wildlife habitat maintenance is workable if species composition changes are not important.

  12. Tevatron serial data repeater system

    International Nuclear Information System (INIS)

    Ducar, R.J.

    1981-01-01

    A ten megabit per second serial data repeater system has been developed for the 6.28km Tevatron accelerator. The repeaters are positioned at each of the thirty service buildings and accommodate control and abort system communications as well as distribution of the Tevatron time and energy clocks. The repeaters are transparent to the particular protocol of the transmissions. Serial data are encoded locally as unipolar two volt signals employing the self-clocking Manchester Bi-Phase code. The repeaters modulate the local signals to low-power bursts of 50 MHz rf carrier for the 260m transmission between service buildings. The repeaters also demodulate the transmission and restructure the data for local utilization. The employment of frequency discrimination techniques yields high immunity to the characteristic noise spectrum

  13. All-photonic quantum repeaters

    Science.gov (United States)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  14. Repeatability of visual acuity measurement.

    Science.gov (United States)

    Raasch, T W; Bailey, I L; Bullimore, M A

    1998-05-01

    This study investigates features of visual acuity chart design and acuity testing scoring methods which affect the validity and repeatability of visual acuity measurements. Visual acuity was measured using the Sloan and British Standard letter series, and Landolt rings. Identifiability of the different letters as a function of size was estimated, and expressed in the form of frequency-of-seeing curves. These functions were then used to simulate acuity measurements with a variety of chart designs and scoring criteria. Systematic relationships exist between chart design parameters and acuity score, and acuity score repeatability. In particular, an important feature of a chart, that largely determines the repeatability of visual acuity measurement, is the amount of size change attributed to each letter. The methods used to score visual acuity performance also affect repeatability. It is possible to evaluate acuity score validity and repeatability using the statistical principles discussed here.

  15. Clocks around Sgr A*

    Science.gov (United States)

    Angélil, Raymond; Saha, Prasenjit

    2014-11-01

    The S stars near the Galactic Centre and any pulsars that may be on similar orbits can be modelled in a unified way as clocks orbiting a black hole, and hence are potential probes of relativistic effects, including black hole spin. The high eccentricities of many S stars mean that relativistic effects peak strongly around pericentre; for example, orbit precession is not a smooth effect but almost a kick at pericentre. We argue that concentration around pericentre will be an advantage when analysing redshift or pulse-arrival data to measure relativistic effects, because cumulative precession will be drowned out by Newtonian perturbations from other mass in the Galactic Centre region. Wavelet decomposition may be a way to disentangle relativistic effects from Newton perturbations. Assuming a plausible model for Newtonian perturbations on S2, relativity appears to be strongest in a two-year interval around pericentre, in wavelet modes of time-scale ≈6 months.

  16. Analysis of repeated measures data

    CERN Document Server

    Islam, M Ataharul

    2017-01-01

    This book presents a broad range of statistical techniques to address emerging needs in the field of repeated measures. It also provides a comprehensive overview of extensions of generalized linear models for the bivariate exponential family of distributions, which represent a new development in analysing repeated measures data. The demand for statistical models for correlated outcomes has grown rapidly recently, mainly due to presence of two types of underlying associations: associations between outcomes, and associations between explanatory variables and outcomes. The book systematically addresses key problems arising in the modelling of repeated measures data, bearing in mind those factors that play a major role in estimating the underlying relationships between covariates and outcome variables for correlated outcome data. In addition, it presents new approaches to addressing current challenges in the field of repeated measures and models based on conditional and joint probabilities. Markov models of first...

  17. Repeated DNA sequences in fungi

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, S K

    1974-11-01

    Several fungal species, representatives of all broad groups like basidiomycetes, ascomycetes and phycomycetes, were examined for the nature of repeated DNA sequences by DNA:DNA reassociation studies using hydroxyapatite chromatography. All of the fungal species tested contained 10 to 20 percent repeated DNA sequences. There are approximately 100 to 110 copies of repeated DNA sequences of approximately 4 x 10/sup 7/ daltons piece size of each. Repeated DNA sequence homoduplexes showed on average 5/sup 0/C difference of T/sub e/50 (temperature at which 50 percent duplexes dissociate) values from the corresponding homoduplexes of unfractionated whole DNA. It is suggested that a part of repetitive sequences in fungi constitutes mitochondrial DNA and a part of it constitutes nuclear DNA. (auth)

  18. Fostering repeat donations in Ghana.

    Science.gov (United States)

    Owusu-Ofori, S; Asenso-Mensah, K; Boateng, P; Sarkodie, F; Allain, J-P

    2010-01-01

    Most African countries are challenged in recruiting and retaining voluntary blood donors by cost and other complexities and in establishing and implementing national blood policies. The availability of replacement donors who are a cheaper source of blood has not enhanced repeat voluntary donor initiatives. An overview of activities for recruiting and retaining voluntary blood donors was carried out. Donor records from mobile sessions were reviewed from 2002 to 2008. A total of 71,701 blood donations; 45,515 (63.5%) being voluntary donations with 11,680 (25%) repeat donations were collected during the study period. Donations from schools and colleges contributed a steady 60% of total voluntary whilst radio station blood drives increased contribution from 10 to 27%. Though Muslim population is less than 20%, blood collection was above the 30-donation cost-effectiveness threshold with a repeat donation trend reaching 60%. In contrast Christian worshippers provided donations. Repeat donation trends amongst school donors and radio blood drives were 20% and 70% respectively. Repeat donations rates have been variable amongst different blood donor groups in Kumasi, Ghana. The impact of community leaders in propagating altruism cannot be overemphasized. Programs aiming at motivating replacement donors to be repeat donors should be developed and assessed. Copyright 2009 The International Association for Biologicals. All rights reserved.

  19. Extended VHE γ-ray emission towards SGR1806-20, LBV 1806-20, and stellar cluster Cl* 1806-20

    Science.gov (United States)

    H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Angüner, E. O.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Birsin, E.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Couturier, C.; Cui, Y.; Davids, I. D.; Degrange, B.; Deil, C.; deWilt, P.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Grudzińska, M.; Hadasch, D.; Hahn, J.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kerszberg, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Menzler, U.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Morå, K.; Moulin, E.; Murach, T.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de Reyes, R.; Rieger, F.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tluczykont, M.; Trichard, C.; Tuffs, R.; van der Walt, J.; van Eldik, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.

    2018-04-01

    Using the High Energy Spectroscopic System (H.E.S.S.) telescopes we have discovered a steady and extended very high-energy (VHE) γ-ray source towards the luminous blue variable candidate LBV 1806-20, massive stellar cluster Cl* 1806-20, and magnetar SGR 1806-20. The new VHE source, HESS J1808-204, was detected at a statistical significance of >6σ (post-trial) with a photon flux normalisation (2.9 ± 0.4stat ± 0.5sys) × 10-13 ph cm-2 s-1 TeV-1 at 1 TeV and a power-law photon index of 2.3 ± 0.2stat ± 0.3sys. The luminosity of this source (0.2 to 10 TeV; scaled to distance d = 8.7 kpc) is LVHE 1.6 × 1034(d/8.7 kpc)2 erg s-1. The VHE γ-ray emission is extended and is well fit by a single Gaussian with statistical standard deviation of 0.095° ± 0.015°. This extension is similar to that of the synchrotron radio nebula G10.0-0.3, which is thought to be powered by LBV 1806-20. The VHE γ-ray luminosity could be provided by the stellar wind luminosity of LBV 1806-20 by itself and/or the massive star members of Cl* 1806-20. Alternatively, magnetic dissipation (e.g. via reconnection) from SGR 1806-20 can potentially account for the VHE luminosity. The origin and hadronic and/or leptonic nature of the accelerated particles responsible for HESS J1808-204 is not yet clear. If associated with SGR 1806-20, the potentially young age of the magnetar (650 yr) can be used to infer the transport limits of these particles to match the VHE source size. This discovery provides new interest in the potential for high-energy particle acceleration from magnetars, massive stars, and/or stellar clusters.

  20. Hysteresis of magnetostructural transitions: Repeatable and non-repeatable processes

    Science.gov (United States)

    Provenzano, Virgil; Della Torre, Edward; Bennett, Lawrence H.; ElBidweihy, Hatem

    2014-02-01

    The Gd5Ge2Si2 alloy and the off-stoichiometric Ni50Mn35In15 Heusler alloy belong to a special class of metallic materials that exhibit first-order magnetostructural transitions near room temperature. The magnetic properties of this class of materials have been extensively studied due to their interesting magnetic behavior and their potential for a number of technological applications such as refrigerants for near-room-temperature magnetic refrigeration. The thermally driven first-order transitions in these materials can be field-induced in the reverse order by applying a strong enough field. The field-induced transitions are typically accompanied by the presence of large magnetic hysteresis, the characteristics of which are a complicated function of temperature, field, and magneto-thermal history. In this study we show that the virgin curve, the major loop, and sequentially measured MH loops are the results of both repeatable and non-repeatable processes, in which the starting magnetostructural state, prior to the cycling of field, plays a major role. Using the Gd5Ge2Si2 and Ni50Mn35In15 alloys, as model materials, we show that a starting single phase state results in fully repeatable processes and large magnetic hysteresis, whereas a mixed phase starting state results in non-repeatable processes and smaller hysteresis.

  1. Hysteresis of magnetostructural transitions: Repeatable and non-repeatable processes

    International Nuclear Information System (INIS)

    Provenzano, Virgil; Della Torre, Edward; Bennett, Lawrence H.; ElBidweihy, Hatem

    2014-01-01

    The Gd 5 Ge 2 Si 2 alloy and the off-stoichiometric Ni 50 Mn 35 In 15 Heusler alloy belong to a special class of metallic materials that exhibit first-order magnetostructural transitions near room temperature. The magnetic properties of this class of materials have been extensively studied due to their interesting magnetic behavior and their potential for a number of technological applications such as refrigerants for near-room-temperature magnetic refrigeration. The thermally driven first-order transitions in these materials can be field-induced in the reverse order by applying a strong enough field. The field-induced transitions are typically accompanied by the presence of large magnetic hysteresis, the characteristics of which are a complicated function of temperature, field, and magneto-thermal history. In this study we show that the virgin curve, the major loop, and sequentially measured MH loops are the results of both repeatable and non-repeatable processes, in which the starting magnetostructural state, prior to the cycling of field, plays a major role. Using the Gd 5 Ge 2 Si 2 and Ni 50 Mn 35 In 15 alloys, as model materials, we show that a starting single phase state results in fully repeatable processes and large magnetic hysteresis, whereas a mixed phase starting state results in non-repeatable processes and smaller hysteresis

  2. GREEN BANK TELESCOPE AND SWIFT X-RAY TELESCOPE OBSERVATIONS OF THE GALACTIC CENTER RADIO MAGNETAR SGR J1745–2900

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, Ryan S.; Archibald, Robert F.; Kaspi, Victoria M.; Scholz, Paul, E-mail: rlynch@physics.mcgill.ca [Department of Physics, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8 (Canada)

    2015-06-20

    We present results from eight months of Green Bank Telescope 8.7 GHz observations and nearly 18 months of Swift X-ray telescope observations of the radio magnetar SGR J1745–2900. We tracked the radio and X-ray flux density, polarization properties, profile evolution, rotation, and single-pulse behavior. We identified two main periods of activity. The first is characterized by approximately 5.5 months of relatively stable evolution in radio flux density, rotation, and profile shape, while in the second these properties varied substantially. Specifically, a third profile component emerged and the radio flux also became more variable. The single pulse properties also changed, most notably with a larger fraction of pulses with pulse widths ∼5–20 ms in the erratic state. Bright single pulses are well described by a log-normal energy distribution at low energies, but with an excess at high energies. The 2–10 keV flux decayed steadily since the initial X-ray outburst, while the radio flux remained stable to within ∼20% during the stable state. A joint pulsar timing analysis of the radio and X-ray data shows a level of timing noise unprecedented in a radio magnetar, though during the time covered by the radio data alone the timing noise was at a level similar to that observed in other radio magnetars. While SGR J1745–2900 is similar to other radio magnetars in many regards, it differs by having experienced a period of relative stability in the radio that now appears to have ended, while the X-ray properties evolved independently.

  3. X-Ray and Radio Observations of the Magnetar SGR J1935+2154 during Its 2014, 2015, and 2016 Outbursts

    Energy Technology Data Exchange (ETDEWEB)

    Younes, George; Kouveliotou, Chryssa; Van der Horst, Alexander J. [Department of Physics, The George Washington University, Washington, DC 20052 (United States); Jaodand, Amruta; Hessels, Jason W. T. [ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo (Netherlands); Baring, Matthew G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Harding, Alice K.; Gehrels, Neil [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gill, Ramandeep; Granot, Jonathan [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raánana 43537 (Israel); Huppenkothen, Daniela [Center for Data Science, New York University, 726 Broadway, 7th Floor, New York, NY 10003 (United States); Göğüş, Ersin [Sabancı University, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Lin, Lin, E-mail: gyounes@gwu.edu [Department of Astronomy, Beijing Normal University, Beijing 100875 (China)

    2017-10-01

    We analyzed broadband X-ray and radio data of the magnetar SGR J1935+2154 taken in the aftermath of its 2014, 2015, and 2016 outbursts. The source soft X-ray spectrum <10 keV is well described with a blackbody+power-law (BB+PL) or 2BB model during all three outbursts. Nuclear Spectroscopic Telescope Array observations revealed a hard X-ray tail, with a PL photon index Γ = 0.9, extending up to 50 keV, with flux comparable to the one detected <10 keV. Imaging analysis of Chandra data did not reveal small-scale extended emission around the source. Following the outbursts, the total 0.5–10 keV flux from SGR J1935+2154 increased in concordance to its bursting activity, with the flux at activation onset increasing by a factor of ∼7 following its strongest 2016 June outburst. A Swift /X-Ray Telescope observation taken 1.5 days prior to the onset of this outburst showed a flux level consistent with quiescence. We show that the flux increase is due to the PL or hot BB component, which increased by a factor of 25 compared to quiescence, while the cold BB component kT = 0.47 keV remained more or less constant. The 2014 and 2015 outbursts decayed quasi-exponentially with timescales of ∼40 days, while the stronger 2016 May and June outbursts showed a quick short-term decay with timescales of about four days. Our Arecibo radio observations set the deepest limits on the radio emission from a magnetar, with a maximum flux density limit of 14 μ Jy for the 4.6 GHz observations and 7 μ Jy for the 1.4 GHz observations. We discuss these results in the framework of the current magnetar theoretical models.

  4. Coordination in continuously repeated games

    NARCIS (Netherlands)

    Weeren, A.J.T.M.; Schumacher, J.M.; Engwerda, J.C.

    1995-01-01

    In this paper we propose a model to describe the effectiveness of coordination in a continuously repeated two-player game. We study how the choice of a decision rule by a coordinator affects the strategic behavior of the players, resulting in more or less cooperation. Our model requires the analysis

  5. Repeated checking causes memory distrust

    NARCIS (Netherlands)

    van den Hout, M.; Kindt, M.

    2003-01-01

    This paper attempts to explain why in obsessive-compulsive disorder (OCD) checkers distrust in memory persists despite extensive checking. It is argued that: (1) repeated checking increases familiarity with the issues checked; (2) increased familiarity promotes conceptual processing which inhibits

  6. Online learning in repeated auctions

    OpenAIRE

    Weed, Jonathan; Perchet, Vianney; Rigollet, Philippe

    2015-01-01

    Motivated by online advertising auctions, we consider repeated Vickrey auctions where goods of unknown value are sold sequentially and bidders only learn (potentially noisy) information about a good's value once it is purchased. We adopt an online learning approach with bandit feedback to model this problem and derive bidding strategies for two models: stochastic and adversarial. In the stochastic model, the observed values of the goods are random variables centered around the true value of t...

  7. A repeating fast radio burst.

    Science.gov (United States)

    Spitler, L G; Scholz, P; Hessels, J W T; Bogdanov, S; Brazier, A; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J; Ferdman, R D; Freire, P C C; Kaspi, V M; Lazarus, P; Lynch, R; Madsen, E C; McLaughlin, M A; Patel, C; Ransom, S M; Seymour, A; Stairs, I H; Stappers, B W; van Leeuwen, J; Zhu, W W

    2016-03-10

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  8. Improving repeatability by improving quality

    Energy Technology Data Exchange (ETDEWEB)

    Ronen, Shuki; Ackers, Mark; Schlumberger, Geco-Prakla; Brink, Mundy

    1998-12-31

    Time lapse (4-D) seismic is a promising tool for reservoir characterization and monitoring. The method is apparently simple: to acquire data repeatedly over the same reservoir, process and interpret the data sets, then changes between the data sets indicate changes in the reservoir. A problem with time lapse seismic data is that reservoirs are a relatively small part of the earth and important reservoir changes may cause very small differences to the time lapse data. The challenge is to acquire and process economical time lapse data such that reservoir changes can be detected above the noise of varying acquisition and environment. 7 refs., 9 figs.

  9. Telomerase Repeated Amplification Protocol (TRAP).

    Science.gov (United States)

    Mender, Ilgen; Shay, Jerry W

    2015-11-20

    Telomeres are found at the end of eukaryotic linear chromosomes, and proteins that bind to telomeres protect DNA from being recognized as double-strand breaks thus preventing end-to-end fusions (Griffith et al. , 1999). However, due to the end replication problem and other factors such as oxidative damage, the limited life span of cultured cells (Hayflick limit) results in progressive shortening of these protective structures (Hayflick and Moorhead, 1961; Olovnikov, 1973). The ribonucleoprotein enzyme complex telomerase-consisting of a protein catalytic component hTERT and a functional RNA component hTR or hTERC - counteracts telomere shortening by adding telomeric repeats to the end of chromosomes in ~90% of primary human tumors and in some transiently proliferating stem-like cells (Shay and Wright, 1996; Shay and Wright, 2001). This results in continuous proliferation of cells which is a hallmark of cancer. Therefore, telomere biology has a central role in aging, cancer progression/metastasis as well as targeted cancer therapies. There are commonly used methods in telomere biology such as Telomere Restriction Fragment (TRF) (Mender and Shay, 2015b), Telomere Repeat Amplification Protocol (TRAP) and Telomere dysfunction Induced Foci (TIF) analysis (Mender and Shay, 2015a). In this detailed protocol we describe Telomere Repeat Amplification Protocol (TRAP). The TRAP assay is a popular method to determine telomerase activity in mammalian cells and tissue samples (Kim et al. , 1994). The TRAP assay includes three steps: extension, amplification, and detection of telomerase products. In the extension step, telomeric repeats are added to the telomerase substrate (which is actually a non telomeric oligonucleotide, TS) by telomerase. In the amplification step, the extension products are amplified by the polymerase chain reaction (PCR) using specific primers (TS upstream primer and ACX downstream primer) and in the detection step, the presence or absence of telomerase is

  10. Coordinated hybrid automatic repeat request

    KAUST Repository

    Makki, Behrooz

    2014-11-01

    We develop a coordinated hybrid automatic repeat request (HARQ) approach. With the proposed scheme, if a user message is correctly decoded in the first HARQ rounds, its spectrum is allocated to other users, to improve the network outage probability and the users\\' fairness. The results, which are obtained for single- and multiple-antenna setups, demonstrate the efficiency of the proposed approach in different conditions. For instance, with a maximum of M retransmissions and single transmit/receive antennas, the diversity gain of a user increases from M to (J+1)(M-1)+1 where J is the number of users helping that user.

  11. The {sup 12}C/{sup 13}C Ratio in Sgr B2(N): Constraints for Galactic Chemical Evolution and Isotopic Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Halfen, D. T.; Ziurys, L. M. [Department of Chemistry and Biochemistry, University of Arizona, 1305 E. 4th Street, Tucson, AZ 85719 (United States); Woolf, N. J., E-mail: halfend@email.arizona.edu [Department of Astronomy, Arizona Radio Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2017-08-20

    A study has been conducted of {sup 12}C/{sup 13}C ratios in five complex molecules in the Galactic center. H{sub 2}CS, CH{sub 3}CCH, NH{sub 2}CHO, CH{sub 2}CHCN, and CH{sub 3}CH{sub 2}CN and their {sup 13}C-substituted species have been observed in numerous transitions at 1, 2, and 3 mm, acquired in a spectral-line survey of Sgr B2(N), conducted with the telescopes of the Arizona Radio Observatory (ARO). Between 22 and 54 individual, unblended lines for the {sup 12}C species and 2–54 for {sup 13}C-substituted analogs were modeled in a global radiative transfer analysis. All five molecules were found to consistently exhibit two velocity components near V {sub LSR} ∼ 64 and 73 km s{sup −1}, with column densities ranging from N {sub tot} ∼ 3 × 10{sup 14} − 4 × 10{sup 17} cm{sup −2} and ∼2 × 10{sup 13} − 1 × 10{sup 17} cm{sup −2} for the {sup 12}C and {sup 13}C species, respectively. Based on 14 different isotopic combinations, ratios were obtained in the range {sup 12}C/{sup 13}C = 15 ± 5 to 33 ± 13, with an average value of 24 ± 7, based on comparison of column densities. These measurements better anchor the {sup 12}C/{sup 13}C ratio at the Galactic center, and suggest a slightly revised isotope gradient of {sup 12}C/{sup 13}C = 5.21(0.52) D {sub GC} + 22.6(3.3). As indicated by the column densities, no preferential {sup 13}C enrichment was found on the differing carbon sites of CH{sub 3}CCH, CH{sub 2}CHCN, and CH{sub 3}CH{sub 2}CN. Because of the elevated temperatures in Sgr B2(N), {sup 13}C isotopic substitution is effectively “scrambled,” diminishing chemical fractionation effects. The resulting ratios thus reflect stellar nucleosynthesis and Galactic chemical evolution, as is likely the case for most warm clouds.

  12. Nonparametric additive regression for repeatedly measured data

    KAUST Repository

    Carroll, R. J.; Maity, A.; Mammen, E.; Yu, K.

    2009-01-01

    We develop an easily computed smooth backfitting algorithm for additive model fitting in repeated measures problems. Our methodology easily copes with various settings, such as when some covariates are the same over repeated response measurements

  13. A pacemaker with P = 2.48 h modulated the generator of flares in the X-ray light curve of Sgr A* in the year 2012

    Science.gov (United States)

    Leibowitz, Elia

    2017-01-01

    In an intensive observational campaign in the nine month duration of Chandra X-ray Visionary Project that was conducted in the year 2012, 39 large X-ray flares of Sgr A* were recorded. An analysis of the times of the observed flares reveals that the 39 flares are separated in time by intervals that are grouped around integer numbers times 0.10333 days. This time interval is thus the period of a uniform grid of equally spaced points on the time axis. The grouping of the flares around tic marks of this grid is derived from the data with at least a 3.2 σ level of statistical significance. No signal of any period can be found among 22 flares recorded by Chandra in the years 2013-2014. If the 0.10333 day period is that of a nearly circular Keplerian orbit around the blackhole at the center of the Galaxy, its radius is at 7.6 Schwarzschild radii. Large flares were more likely to be triggered when the agent responsible for their outbursts was near the peri-center phase of its slightly eccentric orbit.

  14. Obtención de la curva de luz en la ocultación de 35 Sgr por Júpiter el 6 de marzo de 1996

    Science.gov (United States)

    Paolantonio, S.; Duffard, R.; Carranza, G.

    La ocultación de la estrella de quinta magnitud 35 Sgr por Júpiter, se produjo el 6 de Marzo de 1996 a las 13 hs. TU. El objetivo era medir el cambio del flujo de la estrella en el ingreso y egreso por el limbo del planeta. Con estos datos se pueden determinar parámetros físicos del planeta (radio, eccentricidad) y de su atmósfera (escala de altura, temperatura, densidad, presión) Para lograr ésto se programó la cámara CCD TH 7896 1024 x 1025 instalada en el telescopio de 1.54 m de Bosque Alegre con el objetivo de lograr 2 imágenes por segundo. De esta forma se obtuvieron 2100 imágenes de la inmersión y otras tantas de la emersión. Hubo que tener grandes precauciones para evitar la saturación del CCD ya que la observación se realizó de día. En este momento las imágenes se encuentran en el Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, para su reducción.

  15. Purification, crystallization and preliminary X-ray analysis of SGR6054, a Streptomyces homologue of the mycobacterial integration host factor mIHF

    International Nuclear Information System (INIS)

    Nomoto, Ryohei; Tezuka, Takeaki; Miyazono, Ken-ichi; Tanokura, Masaru; Horinouchi, Sueharu; Ohnishi, Yasuo

    2012-01-01

    A Streptomyces homologue of the mycobacterial integration host factor mIHF was heterologously produced, purified and crystallized in the presence of a 16-mer duplex DNA by the sitting-drop vapour-diffusion method. The best crystal diffracted X-rays to 2.22 Å resolution and belonged to space group C2. The mycobacterial integration host factor (mIHF) is a small nonspecific DNA-binding protein that is essential for the growth of Mycobacterium smegmatis. mIHF homologues are widely distributed among Actinobacteria, and a Streptomyces homologue of mIHF is involved in control of sporulation and antibiotic production in S. coelicolor A3(2). Despite their important biological functions, a structure of mIHF or its homologues has not been elucidated to date. Here, the S. griseus mIHF homologue (SGR6054) was expressed and purified from Escherichia coli and crystallized in the presence of a 16-mer duplex DNA by the sitting-drop vapour-diffusion method. The plate-shaped crystal belonged to space group C2, with unit-cell parameters a = 88.53, b = 69.35, c = 77.71 Å, β = 96.63°, and diffracted X-rays to 2.22 Å resolution

  16. Purification, crystallization and preliminary X-ray analysis of SGR6054, a Streptomyces homologue of the mycobacterial integration host factor mIHF

    Energy Technology Data Exchange (ETDEWEB)

    Nomoto, Ryohei; Tezuka, Takeaki; Miyazono, Ken-ichi; Tanokura, Masaru; Horinouchi, Sueharu; Ohnishi, Yasuo [Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan)

    2012-08-31

    A Streptomyces homologue of the mycobacterial integration host factor mIHF was heterologously produced, purified and crystallized in the presence of a 16-mer duplex DNA by the sitting-drop vapour-diffusion method. The best crystal diffracted X-rays to 2.22 Å resolution and belonged to space group C2. The mycobacterial integration host factor (mIHF) is a small nonspecific DNA-binding protein that is essential for the growth of Mycobacterium smegmatis. mIHF homologues are widely distributed among Actinobacteria, and a Streptomyces homologue of mIHF is involved in control of sporulation and antibiotic production in S. coelicolor A3(2). Despite their important biological functions, a structure of mIHF or its homologues has not been elucidated to date. Here, the S. griseus mIHF homologue (SGR6054) was expressed and purified from Escherichia coli and crystallized in the presence of a 16-mer duplex DNA by the sitting-drop vapour-diffusion method. The plate-shaped crystal belonged to space group C2, with unit-cell parameters a = 88.53, b = 69.35, c = 77.71 Å, β = 96.63°, and diffracted X-rays to 2.22 Å resolution.

  17. Topological characteristics of helical repeat proteins

    NARCIS (Netherlands)

    Groves, M R; Barford, D

    The recent elucidation of protein structures based upon repeating amino acid motifs, including the armadillo motif, the HEAT motif and tetratricopeptide repeats, reveals that they belong to the class of helical repeat proteins. These proteins share the common property of being assembled from tandem

  18. Digital storage of repeated signals

    International Nuclear Information System (INIS)

    Prozorov, S.P.

    1984-01-01

    An independent digital storage system designed for repeated signal discrimination from background noises is described. The signal averaging is performed off-line in the real time mode by means of multiple selection of the investigated signal and integration in each point. Digital values are added in a simple summator and the result is recorded the storage device with the volume of 1024X20 bit from where it can be output on an oscillograph, a plotter or transmitted to a compUter for subsequent processing. The described storage is reliable and simple device on one base of which the systems for the nuclear magnetic resonapce signal acquisition in different experiments are developed

  19. Hungarian repeat station survey, 2010

    Directory of Open Access Journals (Sweden)

    Péter Kovács

    2013-03-01

    Full Text Available The last Hungarian repeat station survey was completed between October 2010 and February 2011. Declination, inclination and the total field were observed using one-axial DMI fluxgate magnetometer mounted on Zeiss20A theodolite and GSM 19 Overhauser magnetometer. The magnetic elements of the sites were reduced to the epoch of 2010.5 on the basis of the continuous recordings of Tihany Geophysical Observatory. In stations located far from the reference observatory, the observations were carried out in the morning and afternoon in order to decrease the effect of the distant temporal correction. To further increase the accuracy, on-site dIdD variometer has also been installed near the Aggtelek station, in the Baradla cave, during the survey of the easternmost sites. The paper presents the technical details and the results of our last campaign. The improvement of the accuracy of the temporal reduction by the use of the local variometer is also reported.

  20. Linear Synchronous Motor Repeatability Tests

    International Nuclear Information System (INIS)

    Ward, C.R.

    2002-01-01

    A cart system using linear synchronous motors was being considered for the Plutonium Immobilization Plant (PIP). One of the applications in the PIP was the movement of a stack of furnace trays, filled with the waste form (pucks) from a stacking/unstacking station to several bottom loaded furnaces. A system was ordered to perform this function in the PIP Ceramic Prototype Test Facility (CPTF). This system was installed and started up in SRTC prior to being installed in the CPTF. The PIP was suspended and then canceled after the linear synchronous motor system was started up. This system was used to determine repeatability of a linear synchronous motor cart system for the Modern Pit Facility

  1. Two-dimensional quantum repeaters

    Science.gov (United States)

    Wallnöfer, J.; Zwerger, M.; Muschik, C.; Sangouard, N.; Dür, W.

    2016-11-01

    The endeavor to develop quantum networks gave rise to a rapidly developing field with far-reaching applications such as secure communication and the realization of distributed computing tasks. This ultimately calls for the creation of flexible multiuser structures that allow for quantum communication between arbitrary pairs of parties in the network and facilitate also multiuser applications. To address this challenge, we propose a two-dimensional quantum repeater architecture to establish long-distance entanglement shared between multiple communication partners in the presence of channel noise and imperfect local control operations. The scheme is based on the creation of self-similar multiqubit entanglement structures at growing scale, where variants of entanglement swapping and multiparty entanglement purification are combined to create high-fidelity entangled states. We show how such networks can be implemented using trapped ions in cavities.

  2. Hybrid FRC under repeated loading

    International Nuclear Information System (INIS)

    Komlos, K.; Babal, B.; Nuernbergerova, T.

    1993-01-01

    Fibre reinforced concretes (FRC) containing several volume fractions in different ratios of two types of fibres - polypropylene and steel, were tested under repeated loading. Mechanical properties of specimens - cubes 150/150/150 mm (for compressive strength), prisms 100/100/400 (for flexural strength), short cylinders 150/60 mm (for impact strength) have been experimentally investigated before and after cyclic loading at the age of 28 days curing time. Mix proportions were designed after DIN 1045 with max. aggregate size 8 mm and grading curve B 8. Portland Cement PC 400 in the amount of 450 kg. m -3 was applied and W/C ratio 0.55. Workability of mixes was measured by Vebe method and regulated by plasticizing admixture Ligoplast Na. Maximum hybrid fibre volume fraction (polypropylene + steel) was 1.0%. Dynamic forces generated in Schenck testing machine with frequency 16 Hz had sinusoidal wave form varying between 0.7 and 0.1 of static mechanical characteristics. The number of cycles in all tests was 10 5 . The residual MOR at static four point bending test and working diagram force-deflection was carried out as well. The impact properties after repeated loading in compression were tested by means of falling weight test. Relationships between composition of fibre composites with different combination of polypropylene (0.2, 0.3, 0.5% by volume) and steel (0.5, 0.7, and 0.8% by volume) fibre content were obtained and technological properties of mixes as well. (author)

  3. Quality control during repeated fryings

    Directory of Open Access Journals (Sweden)

    Cuesta, C.

    1998-08-01

    Full Text Available Most of the debate ¡s about how the slow or frequent turnover of fresh fat affects the deterioration, of fat used in frying. Then, the modification of different oils used in repeated fryings of potatoes without or with turnover of fresh oil, under similar frying conditions, was evaluated by two criteria: by measuring the total polar component isolated by column chromatography and by the evaluation of the specific compounds related to thermoxidative and hydrolytic alteration by High Performance Size Exclusion Chromatography (HPSEC. The results indicate that with frequent turnover of fresh oil, the critical level of 25% of polar material is rarely reached, and there are fewer problems with fat deterioration because the frying tended to increase the level of polar material and thermoxidative compounds (polymers and dimers of triglycerides and oxidized triglycerides in the fryer oil during the first fryings, followed by minor changes and a tendency to reach a near-steady state in successive fryings. However, in repeated frying of potatoes using a null turnover the alteration rate was higher being linear the relationship found between polar material or the different thermoxidative compounds and the number of fryings. On the other hand chemical reactions produced during deep-fat frying can be minimized by using proper oils. In addition the increased level of consumers awareness toward fat composition and its impact on human health could had an impact on the selection of fats for snacks and for industry. In this way monoenic fats are the most adequate from a nutritional point of view and for its oxidative stability during frying.

  4. The leucine-rich repeat structure.

    Science.gov (United States)

    Bella, J; Hindle, K L; McEwan, P A; Lovell, S C

    2008-08-01

    The leucine-rich repeat is a widespread structural motif of 20-30 amino acids with a characteristic repetitive sequence pattern rich in leucines. Leucine-rich repeat domains are built from tandems of two or more repeats and form curved solenoid structures that are particularly suitable for protein-protein interactions. Thousands of protein sequences containing leucine-rich repeats have been identified by automatic annotation methods. Three-dimensional structures of leucine-rich repeat domains determined to date reveal a degree of structural variability that translates into the considerable functional versatility of this protein superfamily. As the essential structural principles become well established, the leucine-rich repeat architecture is emerging as an attractive framework for structural prediction and protein engineering. This review presents an update of the current understanding of leucine-rich repeat structure at the primary, secondary, tertiary and quaternary levels and discusses specific examples from recently determined three-dimensional structures.

  5. Quasi-periodic oscillations in short recurring bursts of the soft gamma repeater J1550–5418

    Energy Technology Data Exchange (ETDEWEB)

    Huppenkothen, D.; D' Angelo, C.; Watts, A. L.; Heil, L.; Van der Klis, M.; Van der Horst, A. J. [Astronomical Institute " Anton Pannekoek," University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Kouveliotou, C. [Astrophysics Office, ZP 12, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Göğüş, E.; Kaneko, Y. [SabancıUniversity, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Ra' anana 43537 (Israel); Lin, L. [François Arago Centre, APC, 10 rue Alice Domon et Léonie Duquet, F-75205 Paris (France); Von Kienlin, A. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Younes, G., E-mail: D.Huppenkothen@uva.nl [NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States)

    2014-06-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. The scarcity of giant flares makes a search for QPOs in the shorter, far more numerous bursts from soft gamma repeaters (SGRs) desirable. In Huppenkothen et al., we developed a Bayesian method for searching for QPOs in short magnetar bursts, taking into account the effects of the complicated burst structure, and have shown its feasibility on a small sample of bursts. Here we apply the same method to a much larger sample from a burst storm of 286 bursts from SGR J1550–5418. We report a candidate signal at 260 Hz in a search of the individual bursts, which is fairly broad. We also find two QPOs at ∼93 Hz, and one at 127 Hz, when averaging periodograms from a number of bursts in individual triggers, at frequencies close to QPOs previously observed in magnetar giant flares. Finally, for the first time, we explore the overall burst variability in the sample and report a weak anti-correlation between the power-law index of the broadband model characterizing aperiodic burst variability and the burst duration: shorter bursts have steeper power-law indices than longer bursts. This indicates that longer bursts vary over a broader range of timescales and are not simply longer versions of the short bursts.

  6. Psicoterapia de grupo de apoio multifamiliar (PGA em hospital-dia (HD psiquiátrico Multifamily support group psychotherapy for relatives (SGR in a psychiatric day hospital program (DH

    Directory of Open Access Journals (Sweden)

    José Onildo B. Contel

    1999-12-01

    Full Text Available INTRODUÇÃO: O familiar é a ponte, entre o ambiente da casa do paciente e o ambiente terapêutico do hospital-dia (HD, onde o paciente permanece das 7h30 às 15h30, de segunda a sexta-feira. A complexidade para a integração do exercício dessa tarefa e suas conseqüências para o tratamento em HD, levou-nos a criar a Psicoterapia de Grupo de Apoio multifamiliar (PGA para facilitar o exame das vissicitudes desta via de duas mãos entre a residência e o HD. OBJETIVOS: As características, liderança e fatores terapêuticos de Yalom nessa PGA serão objetos do presente trabalho MÉTODO: A PGA é um grupo aberto com 1 h e 15 minutos de duração, de freqüência semanal e com coordenação, em coterapia, de um psicoterapeuta de grupo e de uma enfermeira psiquiátrica. RESULTADOS E DISCUSSÃO: Os resultados foram obtidos pelo exame de 20 grupos sucessivos, tanto após cada sessão, pelos coterapeutas e observador mudo, durante 20-30 min, como pela análise de conteúdo de 20 sessões transcritas. A presença sempre foi maior que 80% dos familiares esperados, com predomínio de mulheres, especialmente mães de pacientes. A estrutura oferecida pela liderança apressou a obtenção de resultados no curto prazo, entre 4 a 6 sessões. A Coesão Grupal de Yalom apareceu em situações comuns e criou um senso de união entre todos. CONCLUSÃO: A adesão de familiares à PGA facilita e abrevia a terapia em HD. Questiona-se quanto, no futuro, a família orientada assumirá na condução do tratamento dos seus pacientes.INTRODUCTION: The relative is the bridge between the patient's home environment and the therapeutic environment of the day-hospital (DH. The difficulties for the relative to play this task gave birth to the multi-family support group therapy (SGR. To describe the features, leadership and Yalom's therapeutic factors in the SGR is the aim of this paper. METHOD: The SGR is an open group that last for one hour and 15 minutes, meets once weekly

  7. Repeatability & Workability Evaluation of SIGMOD 2009

    KAUST Repository

    Manegold, Stefan

    2010-12-15

    SIGMOD 2008 was the first database conference that offered to test submitters\\' programs against their data to verify the repeatability of the experiments published [1]. Given the positive feedback concerning the SIGMOD 2008 repeatability initiative, SIGMOD 2009 modified and expanded the initiative with a workability assessment.

  8. simple sequence repeats (EST-SSR)

    African Journals Online (AJOL)

    Yomi

    2012-01-19

    Jan 19, 2012 ... 212 primer pairs selected, based on repeat patterns of n≥8 for di-, tri-, tetra- and penta-nucleotide repeat ... Cluster analysis revealed a high genetic similarity among the sugarcane (Saccharum spp.) breeding lines which could reduce the genetic gain in ..... The multiple allele characteristic of SSR com-.

  9. Repeatability & Workability Evaluation of SIGMOD 2009

    KAUST Repository

    Manegold, Stefan; Manolescu, Ioana; Afanasiev, Loredana; Feng, Jieling; Gou, G.; Hadjieleftheriou, Marios; Harizopoulos, Stavros; Kalnis, Panos; Karanasos, Konstantinos; Laurent, Dominique; Lupu, M.; Onose, N.; Ré , C.; Sans, Virginie; Senellart, Pierre; Wu, T.; Shasha, Dennis E.

    2010-01-01

    SIGMOD 2008 was the first database conference that offered to test submitters' programs against their data to verify the repeatability of the experiments published [1]. Given the positive feedback concerning the SIGMOD 2008 repeatability initiative, SIGMOD 2009 modified and expanded the initiative with a workability assessment.

  10. UK 2009-2010 repeat station report

    Directory of Open Access Journals (Sweden)

    Thomas J.G. Shanahan

    2013-03-01

    Full Text Available The British Geological Survey is responsible for conducting the UK geomagnetic repeat station programme. Measurements made at the UK repeat station sites are used in conjunction with the three UK magnetic observatories: Hartland, Eskdalemuir and Lerwick, to produce a regional model of the local field each year. The UK network of repeat stations comprises 41 stations which are occupied at approximately 3-4 year intervals. Practices for conducting repeat station measurements continue to evolve as advances are made in survey instrumentation and as the usage of the data continues to change. Here, a summary of the 2009 and 2010 UK repeat station surveys is presented, highlighting the measurement process and techniques, density of network, reduction process and recent results.

  11. Development of analog watch with minute repeater

    Science.gov (United States)

    Okigami, Tomio; Aoyama, Shigeru; Osa, Takashi; Igarashi, Kiyotaka; Ikegami, Tomomi

    A complementary metal oxide semiconductor with large scale integration was developed for an electronic minute repeater. It is equipped with the synthetic struck sound circuit to generate natural struck sound necessary for the minute repeater. This circuit consists of an envelope curve drawing circuit, frequency mixer, polyphonic mixer, and booster circuit made by using analog circuit technology. This large scale integration is a single chip microcomputer with motor drivers and input ports in addition to the synthetic struck sound circuit, and it is possible to make an electronic system of minute repeater at a very low cost in comparison with the conventional type.

  12. Preventing Repeat Teen Births PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    This 60 second public service announcement is based on the April 2013 CDC Vital Signs report, which discusses repeat teen births and ways teens, parents and guardians, health care providers, and communities can help prevent them.

  13. Digital repeat analysis; setup and operation.

    Science.gov (United States)

    Nol, J; Isouard, G; Mirecki, J

    2006-06-01

    Since the emergence of digital imaging, there have been questions about the necessity of continuing reject analysis programs in imaging departments to evaluate performance and quality. As a marketing strategy, most suppliers of digital technology focus on the supremacy of the technology and its ability to reduce the number of repeats, resulting in less radiation doses given to patients and increased productivity in the department. On the other hand, quality assurance radiographers and radiologists believe that repeats are mainly related to positioning skills, and repeat analysis is the main tool to plan training needs to up-skill radiographers. A comparative study between conventional and digital imaging was undertaken to compare outcomes and evaluate the need for reject analysis. However, digital technology still being at its early development stages, setting a credible reject analysis program became the major task of the study. It took the department, with the help of the suppliers of the computed radiography reader and the picture archiving and communication system, over 2 years of software enhancement to build a reliable digital repeat analysis system. The results were supportive of both philosophies; the number of repeats as a result of exposure factors was reduced dramatically; however, the percentage of repeats as a result of positioning skills was slightly on the increase for the simple reason that some rejects in the conventional system qualifying for both exposure and positioning errors were classified as exposure error. The ability of digitally adjusting dark or light images reclassified some of those images as positioning errors.

  14. Automated genotyping of dinucleotide repeat markers

    Energy Technology Data Exchange (ETDEWEB)

    Perlin, M.W.; Hoffman, E.P. [Carnegie Mellon Univ., Pittsburgh, PA (United States)]|[Univ. of Pittsburgh, PA (United States)

    1994-09-01

    The dinucleotide repeats (i.e., microsatellites) such as CA-repeats are a highly polymorphic, highly abundant class of PCR-amplifiable markers that have greatly streamlined genetic mapping experimentation. It is expected that over 30,000 such markers (including tri- and tetranucleotide repeats) will be characterized for routine use in the next few years. Since only size determination, and not sequencing, is required to determine alleles, in principle, dinucleotide repeat genotyping is easily performed on electrophoretic gels, and can be automated using DNA sequencers. Unfortunately, PCR stuttering with these markers generates not one band for each allele, but a pattern of bands. Since closely spaced alleles must be disambiguated by human scoring, this poses a key obstacle to full automation. We have developed methods that overcome this obstacle. Our model is that the observed data is generated by arithmetic superposition (i.e., convolution) of multiple allele patterns. By quantitatively measuring the size of each component band, and exploiting the unique stutter pattern associated with each marker, closely spaced alleles can be deconvolved; this unambiguously reconstructs the {open_quotes}true{close_quotes} allele bands, with stutter artifact removed. We used this approach in a system for automated diagnosis of (X-linked) Duchenne muscular dystrophy; four multiplexed CA-repeats within the dystrophin gene were assayed on a DNA sequencer. Our method accurately detected small variations in gel migration that shifted the allele size estimate. In 167 nonmutated alleles, 89% (149/167) showed no size variation, 9% (15/167) showed 1 bp variation, and 2% (3/167) showed 2 bp variation. We are currently developing a library of dinucleotide repeat patterns; together with our deconvolution methods, this library will enable fully automated genotyping of dinucleotide repeats from sizing data.

  15. Role of memory errors in quantum repeaters

    International Nuclear Information System (INIS)

    Hartmann, L.; Kraus, B.; Briegel, H.-J.; Duer, W.

    2007-01-01

    We investigate the influence of memory errors in the quantum repeater scheme for long-range quantum communication. We show that the communication distance is limited in standard operation mode due to memory errors resulting from unavoidable waiting times for classical signals. We show how to overcome these limitations by (i) improving local memory and (ii) introducing two operational modes of the quantum repeater. In both operational modes, the repeater is run blindly, i.e., without waiting for classical signals to arrive. In the first scheme, entanglement purification protocols based on one-way classical communication are used allowing to communicate over arbitrary distances. However, the error thresholds for noise in local control operations are very stringent. The second scheme makes use of entanglement purification protocols with two-way classical communication and inherits the favorable error thresholds of the repeater run in standard mode. One can increase the possible communication distance by an order of magnitude with reasonable overhead in physical resources. We outline the architecture of a quantum repeater that can possibly ensure intercontinental quantum communication

  16. Safety of Repeated Yttrium-90 Radioembolization

    International Nuclear Information System (INIS)

    Lam, Marnix G. E. H.; Louie, John D.; Iagaru, Andrei H.; Goris, Michael L.; Sze, Daniel Y.

    2013-01-01

    Purpose: Repeated radioembolization (RE) treatments carry theoretically higher risk of radiation-induced hepatic injury because of the liver’s cumulative memory of previous exposure. We performed a retrospective safety analysis on patients who underwent repeated RE. Methods: From 2004 to 2011, a total of 247 patients were treated by RE. Eight patients (5 men, 3 women, age range 51–71 years) underwent repeated treatment of a targeted territory, all with resin microspheres (SIR-Spheres; Sirtex, Lane Cove, Australia). Adverse events were graded during a standardized follow-up. In addition, the correlation between the occurrence of RE-induced liver disease (REILD) and multiple variables was investigated in univariate and multivariate analyses in all 247 patients who received RE. Results: Two patients died shortly after the second treatment (at 84 and 107 days) with signs and symptoms of REILD. Both patients underwent whole liver treatment twice (cumulative doses 3.08 and 2.66 GBq). The other 6 patients demonstrated only minor toxicities after receiving cumulative doses ranging from 2.41 to 3.88 GBq. All patients experienced objective tumor responses. In the whole population, multifactorial analysis identified three risk factors associated with REILD: repeated RE (p = 0.036), baseline serum total bilirubin (p = 0.048), and baseline serum aspartate aminotransferase (p = 0.043). Repeated RE proved to be the only independent risk factor for REILD in multivariate analysis (odds ratio 9.6; p = 0.002). Additionally, the administered activity per target volume (in GBq/L) was found to be an independent risk factor for REILD, but only in whole liver treatments (p = 0.033). Conclusion: The risk of REILD appears to be elevated for repeated RE. Objective tumor responses were observed, but establishment of safety limits will require improvement in dosimetric measurement and prediction

  17. Repeat Gamma Knife Radiosurgery for Trigeminal Neuralgia

    International Nuclear Information System (INIS)

    Aubuchon, Adam C.; Chan, Michael D.; Lovato, James F.; Balamucki, Christopher J.; Ellis, Thomas L.; Tatter, Stephen B.; McMullen, Kevin P.; Munley, Michael T.; Deguzman, Allan F.; Ekstrand, Kenneth E.; Bourland, J. Daniel; Shaw, Edward G.

    2011-01-01

    Purpose: Repeat gamma knife stereotactic radiosurgery (GKRS) for recurrent or persistent trigeminal neuralgia induces an additional response but at the expense of an increased incidence of facial numbness. The present series summarized the results of a repeat treatment series at Wake Forest University Baptist Medical Center, including a multivariate analysis of the data to identify the prognostic factors for treatment success and toxicity. Methods and Materials: Between January 1999 and December 2007, 37 patients underwent a second GKRS application because of treatment failure after a first GKRS treatment. The mean initial dose in the series was 87.3 Gy (range, 80–90). The mean retreatment dose was 84.4 Gy (range, 60–90). The dosimetric variables recorded included the dorsal root entry zone dose, pons surface dose, and dose to the distal nerve. Results: Of the 37 patients, 81% achieved a >50% pain relief response to repeat GKRS, and 57% experienced some form of trigeminal dysfunction after repeat GKRS. Two patients (5%) experienced clinically significant toxicity: one with bothersome numbness and one with corneal dryness requiring tarsorraphy. A dorsal root entry zone dose at repeat treatment of >26.6 Gy predicted for treatment success (61% vs. 32%, p = .0716). A cumulative dorsal root entry zone dose of >84.3 Gy (72% vs. 44%, p = .091) and a cumulative pons surface dose of >108.5 Gy (78% vs. 44%, p = .018) predicted for post-GKRS numbness. The presence of any post-GKRS numbness predicted for a >50% decrease in pain intensity (100% vs. 60%, p = .0015). Conclusion: Repeat GKRS is a viable treatment option for recurrent trigeminal neuralgia, although the patient assumes a greater risk of nerve dysfunction to achieve maximal pain relief.

  18. Safety of Repeated Yttrium-90 Radioembolization

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Marnix G. E. H.; Louie, John D. [Stanford University School of Medicine, Division of Interventional Radiology (United States); Iagaru, Andrei H.; Goris, Michael L. [Stanford University School of Medicine, Division of Nuclear Medicine (United States); Sze, Daniel Y., E-mail: dansze@stanford.edu [Stanford University School of Medicine, Division of Interventional Radiology (United States)

    2013-10-15

    Purpose: Repeated radioembolization (RE) treatments carry theoretically higher risk of radiation-induced hepatic injury because of the liver's cumulative memory of previous exposure. We performed a retrospective safety analysis on patients who underwent repeated RE. Methods: From 2004 to 2011, a total of 247 patients were treated by RE. Eight patients (5 men, 3 women, age range 51-71 years) underwent repeated treatment of a targeted territory, all with resin microspheres (SIR-Spheres; Sirtex, Lane Cove, Australia). Adverse events were graded during a standardized follow-up. In addition, the correlation between the occurrence of RE-induced liver disease (REILD) and multiple variables was investigated in univariate and multivariate analyses in all 247 patients who received RE. Results: Two patients died shortly after the second treatment (at 84 and 107 days) with signs and symptoms of REILD. Both patients underwent whole liver treatment twice (cumulative doses 3.08 and 2.66 GBq). The other 6 patients demonstrated only minor toxicities after receiving cumulative doses ranging from 2.41 to 3.88 GBq. All patients experienced objective tumor responses. In the whole population, multifactorial analysis identified three risk factors associated with REILD: repeated RE (p = 0.036), baseline serum total bilirubin (p = 0.048), and baseline serum aspartate aminotransferase (p = 0.043). Repeated RE proved to be the only independent risk factor for REILD in multivariate analysis (odds ratio 9.6; p = 0.002). Additionally, the administered activity per target volume (in GBq/L) was found to be an independent risk factor for REILD, but only in whole liver treatments (p = 0.033). Conclusion: The risk of REILD appears to be elevated for repeated RE. Objective tumor responses were observed, but establishment of safety limits will require improvement in dosimetric measurement and prediction.

  19. Repeat Gamma Knife Radiosurgery for Trigeminal Neuralgia

    Energy Technology Data Exchange (ETDEWEB)

    Aubuchon, Adam C., E-mail: acaubuchon@gmail.com [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Chan, Michael D. [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Lovato, James F. [Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Balamucki, Christopher J. [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Ellis, Thomas L.; Tatter, Stephen B. [Department of Neurosurgery, Wake Forest University School of Medicine, Winston-Salem, NC (United States); McMullen, Kevin P.; Munley, Michael T.; Deguzman, Allan F.; Ekstrand, Kenneth E.; Bourland, J. Daniel; Shaw, Edward G. [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States)

    2011-11-15

    Purpose: Repeat gamma knife stereotactic radiosurgery (GKRS) for recurrent or persistent trigeminal neuralgia induces an additional response but at the expense of an increased incidence of facial numbness. The present series summarized the results of a repeat treatment series at Wake Forest University Baptist Medical Center, including a multivariate analysis of the data to identify the prognostic factors for treatment success and toxicity. Methods and Materials: Between January 1999 and December 2007, 37 patients underwent a second GKRS application because of treatment failure after a first GKRS treatment. The mean initial dose in the series was 87.3 Gy (range, 80-90). The mean retreatment dose was 84.4 Gy (range, 60-90). The dosimetric variables recorded included the dorsal root entry zone dose, pons surface dose, and dose to the distal nerve. Results: Of the 37 patients, 81% achieved a >50% pain relief response to repeat GKRS, and 57% experienced some form of trigeminal dysfunction after repeat GKRS. Two patients (5%) experienced clinically significant toxicity: one with bothersome numbness and one with corneal dryness requiring tarsorraphy. A dorsal root entry zone dose at repeat treatment of >26.6 Gy predicted for treatment success (61% vs. 32%, p = .0716). A cumulative dorsal root entry zone dose of >84.3 Gy (72% vs. 44%, p = .091) and a cumulative pons surface dose of >108.5 Gy (78% vs. 44%, p = .018) predicted for post-GKRS numbness. The presence of any post-GKRS numbness predicted for a >50% decrease in pain intensity (100% vs. 60%, p = .0015). Conclusion: Repeat GKRS is a viable treatment option for recurrent trigeminal neuralgia, although the patient assumes a greater risk of nerve dysfunction to achieve maximal pain relief.

  20. Repeating pneumatic pellet injector in JAERI

    International Nuclear Information System (INIS)

    Kasai, Satoshi; Hasegawa, Kouichi; Suzuki, Sadaaki; Miura, Yukitoshi; Oda, Yasushi; Onozuka, Masanori; Tsujimura, Seiichi.

    1992-09-01

    A repeating pneumatic pellet injector has been developed and constructed at Japan Atomic Energy Research Institute. This injector can provide repetitive pellet injection to fuel tokamak plasmas for an extended period of time, aiming at the improvement of plasma performance. The pellets with nearly identical speed and mass can be repeatedly injected with a repetition rate of 2-3.3 Hz and a speed of up to 1.7 km/s by controlling the temperature of the cryogenic system, the piston speed and the pressure of the propellant gas. (author)

  1. Repeating pneumatic pellet injector in JAERI

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Satoshi; Hasegawa, Kouichi; Suzuki, Sadaaki; Miura, Yukitoshi (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment); Oda, Yasushi; Onozuka, Masanori; Tsujimura, Seiichi.

    1992-09-01

    A repeating pneumatic pellet injector has been developed and constructed at Japan Atomic Energy Research Institute. This injector can provide repetitive pellet injection to fuel tokamak plasmas for an extended period of time, aiming at the improvement of plasma performance. The pellets with nearly identical speed and mass can be repeatedly injected with a repetition rate of 2-3.3 Hz and a speed of up to 1.7 km/s by controlling the temperature of the cryogenic system, the piston speed and the pressure of the propellant gas. (author).

  2. Repeating and non-repeating fast radio bursts from binary neutron star mergers

    Science.gov (United States)

    Yamasaki, Shotaro; Totani, Tomonori; Kiuchi, Kenta

    2018-04-01

    Most fast radio bursts (FRB) do not show evidence of repetition, and such non-repeating FRBs may be produced at the time of a merger of binary neutron stars (BNS), provided that the BNS merger rate is close to the high end of the currently possible range. However, the merger environment is polluted by dynamical ejecta, which may prohibit the radio signal from propagating. We examine this by using a general-relativistic simulation of a BNS merger, and show that the ejecta appears about 1 ms after the rotation speed of the merged star becomes the maximum. Therefore there is a time window in which an FRB signal can reach outside, and the short duration of non-repeating FRBs can be explained by screening after ejecta formation. A fraction of BNS mergers may leave a rapidly rotating and stable neutron star, and such objects may be the origin of repeating FRBs like FRB 121102. We show that a merger remnant would appear as a repeating FRB on a time scale of ˜1-10 yr, and expected properties are consistent with the observations of FRB 121102. We construct an FRB rate evolution model that includes these two populations of repeating and non-repeating FRBs from BNS mergers, and show that the detection rate of repeating FRBs relative to non-repeating ones rapidly increases with improving search sensitivity. This may explain why only the repeating FRB 121102 was discovered by the most sensitive FRB search with Arecibo. Several predictions are made, including the appearance of a repeating FRB 1-10 yr after a BNS merger that is localized by gravitational waves and subsequent electromagnetic radiation.

  3. Ecological Panel Inference from Repeated Cross Sections

    NARCIS (Netherlands)

    Pelzer, Ben; Eisinga, Rob; Franses, Philip Hans

    2004-01-01

    This chapter presents a Markov chain model for the estimation of individual-level binary transitions from a time series of independent repeated cross-sectional (RCS) samples. Although RCS samples lack direct information on individual turnover, it is demonstrated here that it is possible with these

  4. Preventing Repeat Teen Births PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2013-04-02

    This 60 second public service announcement is based on the April 2013 CDC Vital Signs report, which discusses repeat teen births and ways teens, parents and guardians, health care providers, and communities can help prevent them.  Created: 4/2/2013 by Centers for Disease Control and Prevention (CDC).   Date Released: 4/2/2013.

  5. Costly renegotiation in repeated Bertand games

    DEFF Research Database (Denmark)

    Andersson, Ola; Wengström, Erik Roland

    2010-01-01

    This paper extends the concept of weak renegotiation-proof equilibrium (WRP) to allow for costly renegotiation and shows that even small renegotiation costs can have dramatic effects on the set of equilibria. More specifically, the paper analyzes the infinitely repeated Bertrand game. It is shown...

  6. On Solving Intransitivities in Repeated Pairwise Choices

    NARCIS (Netherlands)

    A. Maas (Arne); Th.G.G. Bezembinder (Thom); P.P. Wakker (Peter)

    1995-01-01

    textabstractAn operational method is presented for deriving a linear ranking of alternatives from repeated paired comparisons of the alternatives. Intransitivities in the observed preferences are cleared away by the introduction of decision errors of varying importance. An observed preference

  7. Repeated checking induces uncertainty about future threat

    NARCIS (Netherlands)

    Giele, C.L.|info:eu-repo/dai/nl/318754460; Engelhard, I.M.|info:eu-repo/dai/nl/239681533; van den Hout, M.A.|info:eu-repo/dai/nl/070445354; Dek, E.C.P.|info:eu-repo/dai/nl/313959552; Damstra, Marianne; Douma, Ellen

    2015-01-01

    Studies have shown that obsessive-compulsive (OC) -like repeated checking paradoxically increases memory uncertainty. This study tested if checking also induces uncertainty about future threat by impairing the distinction between danger and safety cues. Participants (n = 54) engaged in a simulated

  8. FRB 121102: A Starquake-induced Repeater?

    Science.gov (United States)

    Wang, Weiyang; Luo, Rui; Yue, Han; Chen, Xuelei; Lee, Kejia; Xu, Renxin

    2018-01-01

    Since its initial discovery, the fast radio burst (FRB) FRB 121102 has been found to be repeating with millisecond-duration pulses. Very recently, 14 new bursts were detected by the Green Bank Telescope during its continuous monitoring observations. In this paper, we show that the burst energy distribution has a power-law form which is very similar to the Gutenberg–Richter law of earthquakes. In addition, the distribution of burst waiting time can be described as a Poissonian or Gaussian distribution, which is consistent with earthquakes, while the aftershock sequence exhibits some local correlations. These findings suggest that the repeating FRB pulses may originate from the starquakes of a pulsar. Noting that the soft gamma-ray repeaters (SGRs) also exhibit such distributions, the FRB could be powered by some starquake mechanisms associated with the SGRs, including the crustal activity of a magnetar or solidification-induced stress of a newborn strangeon star. These conjectures could be tested with more repeating samples.

  9. On balanced minimal repeated measurements designs

    Directory of Open Access Journals (Sweden)

    Shakeel Ahmad Mir

    2014-10-01

    Full Text Available Repeated Measurements designs are concerned with scientific experiments in which each experimental unit is assigned more than once to a treatment either different or identical. This class of designs has the property that the unbiased estimators for elementary contrasts among direct and residual effects are obtainable. Afsarinejad (1983 provided a method of constructing balanced Minimal Repeated Measurements designs p < t , when t is an odd or prime power, one or more than one treatment may occur more than once in some sequences and  designs so constructed no longer remain uniform in periods. In this paper an attempt has been made to provide a new method to overcome this drawback. Specifically, two cases have been considered                RM[t,n=t(t-t/(p-1,p], λ2=1 for balanced minimal repeated measurements designs and  RM[t,n=2t(t-t/(p-1,p], λ2=2 for balanced  repeated measurements designs. In addition , a method has been provided for constructing              extra-balanced minimal designs for special case RM[t,n=t2/(p-1,p], λ2=1.

  10. Repeater For A Digital-Communication Bus

    Science.gov (United States)

    Torres-Guzman, Esteban; Olson, Stephen; Heaps, Tim

    1993-01-01

    Digital repeater circuit designed to extend range of communication on MIL-STD-1553 bus beyond original maximum allowable length of 300 ft. Circuit provides two-way communication, one way at time, and conforms to specifications of MIL-STD-1553. Crosstalk and instability eliminated.

  11. Overcoming fixation with repeated memory suppression.

    Science.gov (United States)

    Angello, Genna; Storm, Benjamin C; Smith, Steven M

    2015-01-01

    Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information.

  12. Deception and Retribution in Repeated Ultimatum Bargaining.

    Science.gov (United States)

    Boles; Croson; Murnighan

    2000-11-01

    This paper investigates the dynamics of deception and retribution in repeated ultimatum bargaining. Anonymous dyads exchanged messages and offers in a series of four ultimatum bargaining games that had prospects for relatively large monetary outcomes. Variations in each party's knowledge of the other's resources and alternatives created opportunities for deception. Revelation of prior unknowns exposed deceptions and created opportunities for retribution in subsequent interactions. Results showed that although proposers and responders chose deceptive strategies almost equally, proposers told more outright lies. Both were more deceptive when their private information was never revealed, and proposers were most deceptive when their potential profits were largest. Revelation of proposers' lies had little effect on their subsequent behavior even though responders rejected their offers more than similar offers from truthful proposers or proposers whose prior deceit was never revealed. The discussion and conclusions address the dynamics of deception and retribution in repeated bargaining interactions. Copyright 2000 Academic Press.

  13. Learning With Repeated-Game Strategies

    Directory of Open Access Journals (Sweden)

    Christos A. Ioannou

    2014-07-01

    Full Text Available We use the self-tuning Experience Weighted Attraction model with repeated-game strategies as a computer testbed to examine the relative frequency, speed of convergence and progression of a set of repeated-game strategies in four symmetric 2x2 games: Prisoner's Dilemma, Battle of the Sexes, Stag-Hunt, and Chicken. In the Prisoner's Dilemma game, we fi□nd that the strategy with the most occurrences is the Grim-Trigger. In the Battle of the Sexes game, a cooperative pair that alternates between the two pure-strategy Nash equilibria emerges as the one with the most occurrences. In the Stag-Hunt and Chicken games, the Win-Stay, Lose-Shift and Grim-Trigger strategies are the ones with the most occurrences. Overall, the pairs that converged quickly ended up at the cooperative outcomes, whereas the ones that were extremely slow to reach convergence ended up at non-cooperative outcomes.

  14. Governing conditions of repeatable Barkhausen noise response

    International Nuclear Information System (INIS)

    Stupakov, O.; Pal'a, J.; Takagi, T.; Uchimoto, T.

    2009-01-01

    The paper is devoted to the establishment of experimental conditions, which ensure the repeatability of magnetic Barkhausen noise testing in practice. For this task, the measurements were performed on open flat samples using different experimental configurations, including: different magnetization frequencies, sampling rates, and filter cut-off frequencies; using a sample-wrapped coil and using attached pick-up coils of various dimensions, with different lift-offs of a single yoke magnet and of the attached coil. The sample magnetization was controlled by a vertical array of three Hall sensors; their readings were extrapolated to the sample surface to precisely define its field. After analysis of the results, a scheme for an optimized sensor with a controlled field waveform was suggested to improve the measurement repeatability. The important issues of signal processing and parameter applicability were also discussed in detail.

  15. Nonparametric additive regression for repeatedly measured data

    KAUST Repository

    Carroll, R. J.

    2009-05-20

    We develop an easily computed smooth backfitting algorithm for additive model fitting in repeated measures problems. Our methodology easily copes with various settings, such as when some covariates are the same over repeated response measurements. We allow for a working covariance matrix for the regression errors, showing that our method is most efficient when the correct covariance matrix is used. The component functions achieve the known asymptotic variance lower bound for the scalar argument case. Smooth backfitting also leads directly to design-independent biases in the local linear case. Simulations show our estimator has smaller variance than the usual kernel estimator. This is also illustrated by an example from nutritional epidemiology. © 2009 Biometrika Trust.

  16. Repeated interactions in open quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Bruneau, Laurent, E-mail: laurent.bruneau@u-cergy.fr [Laboratoire AGM, Université de Cergy-Pontoise, Site Saint-Martin, BP 222, 95302 Cergy-Pontoise (France); Joye, Alain, E-mail: Alain.Joye@ujf-grenoble.fr [Institut Fourier, UMR 5582, CNRS-Université Grenoble I, BP 74, 38402 Saint-Martin d’Hères (France); Merkli, Marco, E-mail: merkli@mun.ca [Department of Mathematics and Statistics Memorial University of Newfoundland, St. John' s, NL Canada A1C 5S7 (Canada)

    2014-07-15

    Analyzing the dynamics of open quantum systems has a long history in mathematics and physics. Depending on the system at hand, basic physical phenomena that one would like to explain are, for example, convergence to equilibrium, the dynamics of quantum coherences (decoherence) and quantum correlations (entanglement), or the emergence of heat and particle fluxes in non-equilibrium situations. From the mathematical physics perspective, one of the main challenges is to derive the irreversible dynamics of the open system, starting from a unitary dynamics of the system and its environment. The repeated interactions systems considered in these notes are models of non-equilibrium quantum statistical mechanics. They are relevant in quantum optics, and more generally, serve as a relatively well treatable approximation of a more difficult quantum dynamics. In particular, the repeated interaction models allow to determine the large time (stationary) asymptotics of quantum systems out of equilibrium.

  17. Toxicological characteristics of petroleum products repeated exposure

    Directory of Open Access Journals (Sweden)

    V.M. Rubin

    2015-03-01

    Full Text Available Abstract. The ability of petroleum products to initiate cumulative effects was assessed in experimental intragastric admission to male albino rats for one month. The analysis of skin-resorptive effects was performed using "test-tube" method on the skin of rats’ tails. It has been established that petroleum products can penetrate the intact skin and, with repeated admission, cause a general toxic effect. There were reductions bodyweights, the negative effect on the function of the kidneys and liver, changes of hematological parameters, as well as activation of the antioksidatnoy system. Repeated intragastric administration does not lead to the death of the animals testifying to the lack of accumulation capacity for petroleum products at the level of functional mortal effects, the cumulation coefficient being > 5.1. Negative impact on urinary function and hepatobiliary system, changes in hematological parameters and activation of the «lipid peroxidation – antioksidant defense» were observed.

  18. Childhood experiences and repeated suicidal behavior

    DEFF Research Database (Denmark)

    Krarup, Gertrud; Nielsen, Bent; Rask, P

    1991-01-01

    The aim of this study was to elucidate the influence of various events in childhood on suicidal behavior in adult age. For this purpose, 99 patients admitted to the Department of Psychiatry of Odense University Hospital after making a suicide attempt were followed for 5 years, to register repeated...... that the psychological climate of the home may be more important than the rupture of early home life. It is noteworthy that the group of repeaters, as against the first-evers, could be characterized by personality disorders and abuse, especially of alcohol: disorders known to be precipitated by a discordant childhood....... It is commonly agreed that the experience in childhood of suicidal behavior among family members or other persons in the close environment is of importance in future suicidal risk. The results of this study indicate that the predictive value of this factor mainly applies to attempts with no fatal outcome...

  19. Repeated radiation injuries by fission products

    International Nuclear Information System (INIS)

    Vasilenko, I.Ya.

    1986-01-01

    Attention is given to repeated radiation injuries during internal irradiation of theoretical and practical interest, particularly in case of the intake into organism of young products of nuclear fission (PNF). The results of experiments with dogs with repeated radioactive iodine injury the isotopes of which (131-135sub(I)) constitute a considerable part of PNF activity are discussed. The blood reaction and protein metabolism state have been studied. Observations for dogs have been continued for about 4 years. The doses for thyroid, gastrointestinal tract and liver subjected to the most intensive irradiation consituted in the first series of experiments after the first intake about 3;0.3;0.05 Gy, after the second - 5;0.5;0.08 Gy and in the second series of experiments - 3;0.3;0.05 Gy and 0.6;0.06;0.01 Gy, respectively. Hematologic factors,thyroid function, changes in exchange and immunologic reactivity have been studied. The dogs have been under observation for 5 years. It is shown in case of repeated intake of Isup(131) PNF into animals organism in quantity which does not cause during the acute period a clinically outlined sickness, substantial differences in the organism reaction as compared with the first intake of radionuclides have not been found. The presence of residual radiation injuries did not cause charging action during the acute period during PNF and repeated intake which in the author's opinion testifies to perfection of compensator mechanisms in case of intake of such quantities of radioactive products. At the remote periods blastomogenic action manifested which is estimated as a result of general biological action of radionuclides administered to the organism. The necessity in subsequent investigations for obtaining the data on organism reactivity, clinic and pathogenesis with the aim of prophylaxis and treatment of such injuries is indicated

  20. Repeated extraction of DNA from FTA cards

    DEFF Research Database (Denmark)

    Stangegaard, Michael; Ferrero, Laura; Børsting, Claus

    2011-01-01

    Extraction of DNA using magnetic bead based techniques on automated DNA extraction instruments provides a fast, reliable and reproducible method for DNA extraction from various matrices. However, the yield of extracted DNA from FTA-cards is typically low. Here, we demonstrate that it is possible...... to repeatedly extract DNA from the processed FTA-disk. The method increases the yield from the nanogram range to the microgram range....

  1. Electrochemical detection of DNA triplet repeat expansion

    Czech Academy of Sciences Publication Activity Database

    Fojta, Miroslav; Havran, Luděk; Vojtíšková, Marie; Paleček, Emil

    2004-01-01

    Roč. 126, č. 21 (2004), s. 6532-6533 ISSN 0002-7863 R&D Projects: GA AV ČR IAA4004402; GA AV ČR IBS5004355; GA AV ČR KJB4004302; GA AV ČR KSK4055109 Institutional research plan: CEZ:AV0Z5004920 Keywords : DNA triplet repeat expansion * PCR amplification * neurodegenerative diseases Subject RIV: BO - Biophysics Impact factor: 6.903, year: 2004

  2. Repeatability and Workability Evaluation of SIGMOD 2011

    DEFF Research Database (Denmark)

    2011-01-01

    SIGMOD has offered, since 2008, to verify the experiments published in the papers accepted at the conference. This year, we have been in charge of reproducing the experiments provided by the authors (repeatability), and exploring changes to experiment parameters (workability). In this paper, we a...... find that most experiments are distributed as Linux packages accompanied by instructions on how to setup and run the experiments. We are still far from the vision of executable papers...

  3. Repeat Stereotactic Radiosurgery for Acoustic Neuromas

    International Nuclear Information System (INIS)

    Kano, Hideyuki; Kondziolka, Douglas; Niranjan, Ajay M.Ch.; Flannery, Thomas J.; Flickinger, John C.; Lunsford, L. Dade

    2010-01-01

    Purpose: To evaluate the outcome of repeat stereotactic radiosurgery (SRS) for acoustic neuromas, we assessed tumor control, clinical outcomes, and the risk of adverse radiation effects in patients whose tumors progressed after initial management. Methods and Materials: During a 21-year experience at our center, 1,352 patients underwent SRS as management for their acoustic neuromas. We retrospectively identified 6 patients who underwent SRS twice for the same tumor. The median patient age was 47 years (range, 35-71 years). All patients had imaging evidence of tumor progression despite initial SRS. One patient also had incomplete surgical resection after initial SRS. All patients were deaf at the time of the second SRS. The median radiosurgery target volume at the time of the initial SRS was 0.5 cc and was 2.1 cc at the time of the second SRS. The median margin dose at the time of the initial SRS was 13 Gy and was 11 Gy at the time of the second SRS. The median interval between initial SRS and repeat SRS was 63 months (range, 25-169 months). Results: At a median follow-up of 29 months after the second SRS (range, 13-71 months), tumor control or regression was achieved in all 6 patients. No patient developed symptomatic adverse radiation effects or new neurological symptoms after the second SRS. Conclusions: With this limited experience, we found that repeat SRS for a persistently enlarging acoustic neuroma can be performed safely and effectively.

  4. A Unified Model for Repeating and Non-repeating Fast Radio Bursts

    International Nuclear Information System (INIS)

    Bagchi, Manjari

    2017-01-01

    The model that fast radio bursts (FRBs) are caused by plunges of asteroids onto neutron stars can explain both repeating and non-repeating bursts. If a neutron star passes through an asteroid belt around another star, there would be a series of bursts caused by a series of asteroid impacts. Moreover, the neutron star would cross the same belt repetitively if it were in a binary with the star hosting the asteroid belt, leading to a repeated series of bursts. I explore the properties of neutron star binaries that could lead to the only known repeating FRB so far (FRB121102). In this model, the next two epochs of bursts are expected around 2017 February 27 and 2017 December 18. On the other hand, if the asteroid belt is located around the neutron star itself, then a chance fall of an asteroid from that belt onto the neutron star would lead to a non-repeating burst. Even a neutron star grazing an asteroid belt can lead to a non-repeating burst caused by just one asteroid plunge during the grazing. This is possible even when the neutron star is in a binary with the asteroid-hosting star, if the belt and the neutron star orbit are non-coplanar.

  5. A Unified Model for Repeating and Non-repeating Fast Radio Bursts

    Energy Technology Data Exchange (ETDEWEB)

    Bagchi, Manjari, E-mail: manjari@imsc.res.in [The Institute of Mathematical Sciences (IMSc-HBNI), 4th Cross Road, CIT Campus, Taramani, Chennai 600113 (India)

    2017-04-01

    The model that fast radio bursts (FRBs) are caused by plunges of asteroids onto neutron stars can explain both repeating and non-repeating bursts. If a neutron star passes through an asteroid belt around another star, there would be a series of bursts caused by a series of asteroid impacts. Moreover, the neutron star would cross the same belt repetitively if it were in a binary with the star hosting the asteroid belt, leading to a repeated series of bursts. I explore the properties of neutron star binaries that could lead to the only known repeating FRB so far (FRB121102). In this model, the next two epochs of bursts are expected around 2017 February 27 and 2017 December 18. On the other hand, if the asteroid belt is located around the neutron star itself, then a chance fall of an asteroid from that belt onto the neutron star would lead to a non-repeating burst. Even a neutron star grazing an asteroid belt can lead to a non-repeating burst caused by just one asteroid plunge during the grazing. This is possible even when the neutron star is in a binary with the asteroid-hosting star, if the belt and the neutron star orbit are non-coplanar.

  6. Identifying uniformly mutated segments within repeats.

    Science.gov (United States)

    Sahinalp, S Cenk; Eichler, Evan; Goldberg, Paul; Berenbrink, Petra; Friedetzky, Tom; Ergun, Funda

    2004-12-01

    Given a long string of characters from a constant size alphabet we present an algorithm to determine whether its characters have been generated by a single i.i.d. random source. More specifically, consider all possible n-coin models for generating a binary string S, where each bit of S is generated via an independent toss of one of the n coins in the model. The choice of which coin to toss is decided by a random walk on the set of coins where the probability of a coin change is much lower than the probability of using the same coin repeatedly. We present a procedure to evaluate the likelihood of a n-coin model for given S, subject a uniform prior distribution over the parameters of the model (that represent mutation rates and probabilities of copying events). In the absence of detailed prior knowledge of these parameters, the algorithm can be used to determine whether the a posteriori probability for n=1 is higher than for any other n>1. Our algorithm runs in time O(l4logl), where l is the length of S, through a dynamic programming approach which exploits the assumed convexity of the a posteriori probability for n. Our test can be used in the analysis of long alignments between pairs of genomic sequences in a number of ways. For example, functional regions in genome sequences exhibit much lower mutation rates than non-functional regions. Because our test provides means for determining variations in the mutation rate, it may be used to distinguish functional regions from non-functional ones. Another application is in determining whether two highly similar, thus evolutionarily related, genome segments are the result of a single copy event or of a complex series of copy events. This is particularly an issue in evolutionary studies of genome regions rich with repeat segments (especially tandemly repeated segments).

  7. Multivariate linear models and repeated measurements revisited

    DEFF Research Database (Denmark)

    Dalgaard, Peter

    2009-01-01

    Methods for generalized analysis of variance based on multivariate normal theory have been known for many years. In a repeated measurements context, it is most often of interest to consider transformed responses, typically within-subject contrasts or averages. Efficiency considerations leads...... to sphericity assumptions, use of F tests and the Greenhouse-Geisser and Huynh-Feldt adjustments to compensate for deviations from sphericity. During a recent implementation of such methods in the R language, the general structure of such transformations was reconsidered, leading to a flexible specification...

  8. Repeat Sequence Proteins as Matrices for Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Drummy, L.; Koerner, H; Phillips, D; McAuliffe, J; Kumar, M; Farmer, B; Vaia, R; Naik, R

    2009-01-01

    Recombinant protein-inorganic nanocomposites comprised of exfoliated Na+ montmorillonite (MMT) in a recombinant protein matrix based on silk-like and elastin-like amino acid motifs (silk elastin-like protein (SELP)) were formed via a solution blending process. Charged residues along the protein backbone are shown to dominate long-range interactions, whereas the SELP repeat sequence leads to local protein/MMT compatibility. Up to a 50% increase in room temperature modulus and a comparable decrease in high temperature coefficient of thermal expansion occur for cast films containing 2-10 wt.% MMT.

  9. Mechanical processes with repeated attenuated impacts

    CERN Document Server

    Nagaev, R F

    1999-01-01

    This book is devoted to considering in the general case - using typical concrete examples - the motion of machines and mechanisms of impact and vibro-impact action accompanied by a peculiar phenomenon called "impact collapse". This phenomenon is that after the initial collision, a sequence of repeated gradually quickening collisions of decreasing-to-zero intensity occurs, with the final establishment of protracted contact between the interacting bodies. The initiation conditions of the impact collapse are determined and calculation techniques for the quantitative characteristics of the corresp

  10. Development of repeating pneumatic pellet injector

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Y.; Onozuka, M.; Shimomura, T. (Mitsubishi Heavy Industries Ltd., Kobe (Japan)) (and others)

    1990-01-01

    A repeating pneumatic pellet injector has been constructed to experiment with the technique of continuous injection for fueling fusion reactors. This device is composed of a cryogenic extruder and a gun assembly in (among others) a high-vacuum vessel, diagnostic vessels, LHe, fuel-gas and propellant-gas supply systems, control and data acquisition systems, etc. The performance tests, using hydrogen, have proved that the device provides the function of extruding frozen hydrogen ribbons at the speed of 6 mm s{sup -1}, chambering pellet at the rate of 5 Hz, and injecting pellet at the speed of 900 m s{sup -1}, as planned. (author).

  11. Development of repeating pneumatic pellet injector

    International Nuclear Information System (INIS)

    Oda, Y.; Onozuka, M.; Shimomura, T.

    1990-01-01

    A repeating pneumatic pellet injector has been constructed to experiment with the technique of continuous injection for fueling fusion reactors. This device is composed of a cryogenic extruder and a gun assembly in (among others) a high-vacuum vessel, diagnostic vessels, LHe, fuel-gas and propellant-gas supply systems, control and data acquisition systems, etc. The performance tests, using hydrogen, have proved that the device provides the function of extruding frozen hydrogen ribbons at the speed of 6 mm s -1 , chambering pellet at the rate of 5 Hz, and injecting pellet at the speed of 900 m s -1 , as planned. (author)

  12. Extending Teach and Repeat to Pivoting Wheelchairs

    Directory of Open Access Journals (Sweden)

    Guillermo Del Castillo

    2003-02-01

    Full Text Available The paper extends the teach-and-repeat paradigm that has been successful for the control of holonomic robots to nonholonomic wheelchairs which may undergo pivoting action over the course of their taught movement. Due to the nonholonomic nature of the vehicle kinematics, estimation is required -- in the example given herein, based upon video detection of wall-mounted cues -- both in the teaching and the tracking events. In order to accommodate motion that approaches pivoting action as well as motion that approaches straight-line action, the estimation equations of the Extended Kalman Filter and the control equations are formulated using two different definitions of a nontemporal independent variable. The paper motivates the need for pivoting action in real-life settings by reporting extensively on the abilities and limitations of estimation-based teach-and-repeat action where pivoting and near-pivoting action is disallowed. Following formulation of the equations in the near-pivot mode, the paper reports upon experiments where taught trajectories which entail a seamless mix of near-straight and near-pivot action are tracked.

  13. Repeated proton beam therapy for hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Hashimoto, Takayuki; Tokuuye, Koichi; Fukumitsu, Nobuyoshi; Igaki, Hiroshi; Hata, Masaharu; Kagei, Kenji; Sugahara, Shinji; Ohara, Kiyoshi; Matsuzaki, Yasushi; Akine, Yasuyuki

    2006-01-01

    Purpose: To retrospectively evaluate the safety and effectiveness of repeated proton beam therapy for newly developed or recurrent hepatocellular carcinoma (HCC). Methods and Materials: From June 1989 through July 2000, 225 patients with HCC underwent their first course of proton beam therapy at University of Tsukuba. Of them, 27 with 68 lesions who had undergone two or more courses were retrospectively reviewed in this study. Median interval between the first and second course was 24.5 months (range 3.3-79.8 months). Median total dose of 72 Gy in 16 fractions and 66 Gy in 16 fractions were given for the first course and the rest of the courses, respectively. Results: The 5-year survival rate and median survival period from the beginning of the first course for the 27 patients were 55.6% and 62.2 months, respectively. Five-year local control rate for the 68 lesions was 87.8%. Of the patients, 1 with Child-Pugh class B and another with class C before the last course suffered from acute hepatic failure. Conclusions: Repeated proton beam therapy for HCC is safe when the patient has a target in the peripheral region of the liver and liver function is Child-Pugh class A

  14. Chromosome-specific DNA Repeat Probes

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, Adolf; Weier, Jingly Fung; Weier, Heinz-Ulrich G.

    2006-03-16

    In research as well as in clinical applications, fluorescence in situ hybridization (FISH) has gained increasing popularity as a highly sensitive technique to study cytogenetic changes. Today, hundreds of commercially available DNA probes serve the basic needs of the biomedical research community. Widespread applications, however, are often limited by the lack of appropriately labeled, specific nucleic acid probes. We describe two approaches for an expeditious preparation of chromosome-specific DNAs and the subsequent probe labeling with reporter molecules of choice. The described techniques allow the preparation of highly specific DNA repeat probes suitable for enumeration of chromosomes in interphase cell nuclei or tissue sections. In addition, there is no need for chromosome enrichment by flow cytometry and sorting or molecular cloning. Our PCR-based method uses either bacterial artificial chromosomes or human genomic DNA as templates with {alpha}-satellite-specific primers. Here we demonstrate the production of fluorochrome-labeled DNA repeat probes specific for human chromosomes 17 and 18 in just a few days without the need for highly specialized equipment and without the limitation to only a few fluorochrome labels.

  15. Aggregating quantum repeaters for the quantum internet

    Science.gov (United States)

    Azuma, Koji; Kato, Go

    2017-09-01

    The quantum internet holds promise for accomplishing quantum teleportation and unconditionally secure communication freely between arbitrary clients all over the globe, as well as the simulation of quantum many-body systems. For such a quantum internet protocol, a general fundamental upper bound on the obtainable entanglement or secret key has been derived [K. Azuma, A. Mizutani, and H.-K. Lo, Nat. Commun. 7, 13523 (2016), 10.1038/ncomms13523]. Here we consider its converse problem. In particular, we present a universal protocol constructible from any given quantum network, which is based on running quantum repeater schemes in parallel over the network. For arbitrary lossy optical channel networks, our protocol has no scaling gap with the upper bound, even based on existing quantum repeater schemes. In an asymptotic limit, our protocol works as an optimal entanglement or secret-key distribution over any quantum network composed of practical channels such as erasure channels, dephasing channels, bosonic quantum amplifier channels, and lossy optical channels.

  16. Performance Comparisons of Improved Regular Repeat Accumulate (RA and Irregular Repeat Accumulate (IRA Turbo Decoding

    Directory of Open Access Journals (Sweden)

    Ahmed Abdulkadhim Hamad

    2017-08-01

    Full Text Available In this paper, different techniques are used to improve the turbo decoding of regular repeat accumulate (RA and irregular repeat accumulate (IRA codes. The adaptive scaling of a-posteriori information produced by Soft-output Viterbi decoder (SOVA is proposed. The encoded pilots are another scheme that applied for short length RA codes. This work also suggests a simple and a fast method to generate a random interleaver having a free 4 cycle Tanner graph. Progressive edge growth algorithm (PEG is also studied and simulated to create the Tanner graphs which have a great girth.

  17. Contraceptive Use among Women Seeking Repeat Abortion in ...

    African Journals Online (AJOL)

    AJRH Managing Editor

    Compared with women seeking their first abortion, significantly more repeat abortion clients had ever used contraceptives ... findings, the level of repeat abortions in Europe, .... and contraceptive history, and post-abortion ..... working women.

  18. Methods for analysing cardiovascular studies with repeated measures

    NARCIS (Netherlands)

    Cleophas, T. J.; Zwinderman, A. H.; van Ouwerkerk, B. M.

    2009-01-01

    Background. Repeated measurements in a single subject are generally more similar than unrepeated measurements in different subjects. Unrepeated analyses of repeated data cause underestimation of the treatment effects. Objective. To review methods adequate for the analysis of cardiovascular studies

  19. Discrepancies in reporting the CAG repeat lengths for Huntington's disease

    DEFF Research Database (Denmark)

    Quarrell, Oliver W; Handley, Olivia; O'Donovan, Kirsty

    2011-01-01

    Huntington's disease results from a CAG repeat expansion within the Huntingtin gene; this is measured routinely in diagnostic laboratories. The European Huntington's Disease Network REGISTRY project centrally measures CAG repeat lengths on fresh samples; these were compared with the original...

  20. The absolute number of repeat operations for complex intra ...

    African Journals Online (AJOL)

    abdominal sepsis, questions about futility of treatment frequently arise. This study focuses specifically on patients who required two or more repeat laparotomies and describes the spectrum of disease necessitating multiple repeat laparotomies ...

  1. Novel expressed sequence tag- simple sequence repeats (EST ...

    African Journals Online (AJOL)

    Using different bioinformatic criteria, the SUCEST database was used to mine for simple sequence repeat (SSR) markers. Among 42,189 clusters, 1,425 expressed sequence tag- simple sequence repeats (EST-SSRs) were identified in silico. Trinucleotide repeats were the most abundant SSRs detected. Of 212 primer pairs ...

  2. Erroneous Memories Arising from Repeated Attempts to Remember

    Science.gov (United States)

    Henkel, Linda A.

    2004-01-01

    The impact of repeated and prolonged attempts at remembering on false memory rates was assessed in three experiments. Participants saw and imagined pictures and then made repeated recall attempts before taking a source memory test. Although the number of items recalled increased with repeated tests, the net gains were associated with more source…

  3. Adaptation and complexity in repeated games

    DEFF Research Database (Denmark)

    Maenner, Eliot Alexander

    2008-01-01

    The paper presents a learning model for two-player infinitely repeated games. In an inference step players construct minimally complex inferences of strategies based on observed play, and in an adaptation step players choose minimally complex best responses to an inference. When players randomly...... select an inference from a probability distribution with full support the set of steady states is a subset of the set of Nash equilibria in which only stage game Nash equilibria are played. When players make ‘cautious' inferences the set of steady states is the subset of self-confirming equilibria...... with Nash outcome paths. When players use different inference rules, the set of steady states can lie between the previous two cases...

  4. Aging and repeated thought suppression success.

    Directory of Open Access Journals (Sweden)

    Ann E Lambert

    Full Text Available Intrusive thoughts and attempts to suppress them are common, but while suppression may be effective in the short-term, it can increase thought recurrence in the long-term. Because intentional suppression involves controlled processing, and many aspects of controlled processing decline with age, age differences in thought suppression outcomes may emerge, especially over repeated thought suppression attempts as cognitive resources are expended. Using multilevel modeling, we examined age differences in reactions to thought suppression attempts across four thought suppression sequences in 40 older and 42 younger adults. As expected, age differences were more prevalent during suppression than during free monitoring periods, with younger adults indicating longer, more frequent thought recurrences and greater suppression difficulty. Further, younger adults' thought suppression outcomes changed over time, while trajectories for older adults' were relatively stable. Results are discussed in terms of older adults' reduced thought recurrence, which was potentially afforded by age-related changes in reactive control and distractibility.

  5. Who Repeats Algebra, and How Does Initial Performance Relate to Improvement When the Course Is Repeated?

    Science.gov (United States)

    Fong, Anthony; Jaquet, Karina; Finkelstein, Neal

    2016-01-01

    The information provided in this report shows how students perform when they repeat algebra I and how the level of improvement varies depending on initial course performance and the academic measure (course grades or CST scores). This information can help inform decisions and policies regarding whether and under what circumstances students should…

  6. Repeat Gamma Knife surgery for vestibular schwannomas

    Science.gov (United States)

    Lonneville, Sarah; Delbrouck, Carine; Renier, Cécile; Devriendt, Daniel; Massager, Nicolas

    2015-01-01

    Background: Gamma Knife (GK) surgery is a recognized treatment option for the management of small to medium-sized vestibular schwannoma (VS) associated with high-tumor control and low morbidity. When a radiosurgical treatment fails to stop tumor growth, repeat GK surgery can be proposed in selected cases. Methods: A series of 27 GK retreatments was performed in 25 patients with VS; 2 patients underwent three procedures. The median time interval between GK treatments was 45 months. The median margin dose used for the first, second, and third GK treatments was 12 Gy, 12 Gy, and 14 Gy, respectively. Six patients (4 patients for the second irradiation and 2 patients for the third irradiation) with partial tumor regrowth were treated only on the growing part of the tumor using a median margin dose of 13 Gy. The median tumor volume was 0.9, 2.3, and 0.7 cc for the first, second, and third treatments, respectively. Stereotactic positron emission tomography (PET) guidance was used for dose planning in 6 cases. Results: Mean follow-up duration was 46 months (range 24–110). At the last follow-up, 85% of schwannomas were controlled. The tumor volume decreased, remained unchanged, or increased after retreatment in 15, 8, and 4 cases, respectively. Four patients had PET during follow-up, and all showed a significant metabolic decrease of the tumor. Hearing was not preserved after retreatment in any patients. New facial or trigeminal palsy did not occur after retreatment. Conclusions: Our results support the long-term efficacy and low morbidity of repeat GK treatment for selected patients with tumor growth after initial treatment. PMID:26500799

  7. In situ detection of tandem DNA repeat length

    Energy Technology Data Exchange (ETDEWEB)

    Yaar, R.; Szafranski, P.; Cantor, C.R.; Smith, C.L. [Boston Univ., MA (United States)

    1996-11-01

    A simple method for scoring short tandem DNA repeats is presented. An oligonucleotide target, containing tandem repeats embedded in a unique sequence, was hybridized to a set of complementary probes, containing tandem repeats of known lengths. Single-stranded loop structures formed on duplexes containing a mismatched (different) number of tandem repeats. No loop structure formed on duplexes containing a matched (identical) number of tandem repeats. The matched and mismatched loop structures were enzymatically distinguished and differentially labeled by treatment with S1 nuclease and the Klenow fragment of DNA polymerase. 7 refs., 4 figs.

  8. Studies on Section XI ultrasonic repeatability

    International Nuclear Information System (INIS)

    Jamison, T.D.; McDearman, W.R.

    1981-05-01

    A block representative of a nuclear component has been welded containing intentional defects. Acoustic emission data taken during the welding correlate well with ultrasonic data. Repetitive ultrasonic examinations have been performed by skilled operators using a procedure based on that desribed in ASME Section XI. These examinations were performed by different examination teams using different ultrasonic equipment in such a manner that the effects on the repeatability of the ultrasonic test method caused by the operator and by the use of different equipment could be estimated. It was tentatively concluded that when considering a large number of inspections: (1) there is no significant difference in indication sizing between operators, and (2) there is a significant difference in amplitude and defect sizing when instruments having different, Code acceptable operating characteristics are used. It was determined that the Section XI sizing parameters follow a bivariate normal distribution. Data derived from ultrasonically and physically sizing indications in nuclear components during farication show that the Section XI technique tends to overestimate the size of the reflectors

  9. Short tandem repeat analysis in Japanese population.

    Science.gov (United States)

    Hashiyada, M

    2000-01-01

    Short tandem repeats (STRs), known as microsatellites, are one of the most informative genetic markers for characterizing biological materials. Because of the relatively small size of STR alleles (generally 100-350 nucleotides), amplification by polymerase chain reaction (PCR) is relatively easy, affording a high sensitivity of detection. In addition, STR loci can be amplified simultaneously in a multiplex PCR. Thus, substantial information can be obtained in a single analysis with the benefits of using less template DNA, reducing labor, and reducing the contamination. We investigated 14 STR loci in a Japanese population living in Sendai by three multiplex PCR kits, GenePrint PowerPlex 1.1 and 2.2. Fluorescent STR System (Promega, Madison, WI, USA) and AmpF/STR Profiler (Perkin-Elmer, Norwalk, CT, USA). Genomic DNA was extracted using sodium dodecyl sulfate (SDS) proteinase K or Chelex 100 treatment followed by the phenol/chloroform extraction. PCR was performed according to the manufacturer's protocols. Electrophoresis was carried out on an ABI 377 sequencer and the alleles were determined by GeneScan 2.0.2 software (Perkin-Elmer). In 14 STRs loci, statistical parameters indicated a relatively high rate, and no significant deviation from Hardy-Weinberg equilibrium was detected. We apply this STR system to paternity testing and forensic casework, e.g., personal identification in rape cases. This system is an effective tool in the forensic sciences to obtain information on individual identification.

  10. A Repeated Signal Difference for Recognising Patterns

    Directory of Open Access Journals (Sweden)

    Kieran Greer

    2016-08-01

    Full Text Available This paper describes a new mechanism that might help with defining pattern sequences, by the fact that it can produce an upper bound on the ensemble value that can persistently oscillate with the actual values produced from each pattern. With every firing event, a node also receives an on/off feedback switch. If the node fires then it sends a feedback result depending on the input signal strength. If the input signal is positive or larger, it can store an ‘on’ switch feedback for the next iteration. If the signal is negative or smaller it can store an ‘off’ switch feedback for the next iteration. If the node does not fire, then it does not affect the current feedback situation and receives the switch command produced by the last active pattern event for the same neuron. The upper bound therefore also represents the largest or most enclosing pattern set and the lower value is for the actual set of firing patterns. If the pattern sequence repeats, it will oscillate between the two values, allowing them to be recognised and measured more easily, over time. Tests show that changing the sequence ordering produces different value sets, which can also be measured.

  11. Repeated intravenous doxapram induces phrenic motor facilitation.

    Science.gov (United States)

    Sandhu, M S; Lee, K Z; Gonzalez-Rothi, E J; Fuller, D D

    2013-12-01

    Doxapram is a respiratory stimulant used to treat hypoventilation. Here we investigated whether doxapram could also trigger respiratory neuroplasticity. Specifically, we hypothesized that intermittent delivery of doxapram at low doses would lead to long-lasting increases (i.e., facilitation) of phrenic motor output in anesthetized, vagotomized, and mechanically-ventilated rats. Doxapram was delivered intravenously in a single bolus (2 or 6mg/kg) or as a series of 3 injections (2mg/kg) at 5min intervals. Control groups received pH-matched saline injections (vehicle) or no treatment (anesthesia time control). Doxapram evoked an immediate increase in phrenic output in all groups, but a persistent increase in burst amplitude only occurred after repeated dosing with 2mg/kg. At 60min following the last injection, phrenic burst amplitude was 168±24% of baseline (%BL) in the group receiving 3 injections (Pphrenic response to doxapram (2mg/kg) was reduced by 68% suggesting that at low doses the drug was acting primarily via the carotid chemoreceptors. We conclude that intermittent application of doxapram can trigger phrenic neuroplasticity, and this approach might be of use in the context of respiratory rehabilitation following neurologic injury. © 2013.

  12. Superfamily of ankyrin repeat proteins in tomato.

    Science.gov (United States)

    Yuan, Xiaowei; Zhang, Shizhong; Qing, Xiaohe; Sun, Meihong; Liu, Shiyang; Su, Hongyan; Shu, Huairui; Li, Xinzheng

    2013-07-10

    The ankyrin repeat (ANK) protein family plays a crucial role in plant growth and development and in response to biotic and abiotic stresses. However, no detailed information concerning this family is available for tomato (Solanum lycopersicum) due to the limited information on whole genome sequences. In this study, we identified a total of 130 ANK genes in tomato genome (SlANK), and these genes were distributed across all 12 chromosomes at various densities. And chromosomal localizations of SlANK genes indicated 25 SlANK genes were involved in tandem duplications. Based on their domain composition, all of the SlANK proteins were grouped into 13 subgroups. A combined phylogenetic tree was constructed with the aligned SlANK protein sequences. This tree revealed that the SlANK proteins comprise five major groups. An analysis of the expression profiles of SlANK genes in tomato in different tissues and in response to stresses showed that the SlANK proteins play roles in plant growth, development and stress responses. To our knowledge, this is the first report of a genome-wide analysis of the tomato ANK gene family. This study provides valuable information regarding the classification and putative functions of SlANK genes in tomato. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  13. Multineuronal Spike Sequences Repeat with Millisecond Precision

    Directory of Open Access Journals (Sweden)

    Koki eMatsumoto

    2013-06-01

    Full Text Available Cortical microcircuits are nonrandomly wired by neurons. As a natural consequence, spikes emitted by microcircuits are also nonrandomly patterned in time and space. One of the prominent spike organizations is a repetition of fixed patterns of spike series across multiple neurons. However, several questions remain unsolved, including how precisely spike sequences repeat, how the sequences are spatially organized, how many neurons participate in sequences, and how different sequences are functionally linked. To address these questions, we monitored spontaneous spikes of hippocampal CA3 neurons ex vivo using a high-speed functional multineuron calcium imaging technique that allowed us to monitor spikes with millisecond resolution and to record the location of spiking and nonspiking neurons. Multineuronal spike sequences were overrepresented in spontaneous activity compared to the statistical chance level. Approximately 75% of neurons participated in at least one sequence during our observation period. The participants were sparsely dispersed and did not show specific spatial organization. The number of sequences relative to the chance level decreased when larger time frames were used to detect sequences. Thus, sequences were precise at the millisecond level. Sequences often shared common spikes with other sequences; parts of sequences were subsequently relayed by following sequences, generating complex chains of multiple sequences.

  14. The effect of repeated testing vs repeated practice on skills learning in undergraduate dental education.

    Science.gov (United States)

    Sennhenn-Kirchner, S; Goerlich, Y; Kirchner, B; Notbohm, M; Schiekirka, S; Simmenroth, A; Raupach, T

    2018-02-01

    Recent studies in undergraduate medical education have demonstrated the advantage of repeated testing over repeated practice with regard to knowledge and skills retention. The aim of this study was to investigate whether this "testing effect" also applies to skills retention in undergraduate dental education. In this prospective, randomised controlled trial, fourth-year dental students at Göttingen University Medical Centre participated in a training session on surgical suturing in winter term 2014/2015. Following this, they were either assigned to two sessions of additional skills training (group A) or two sessions of skills assessment with feedback (group B). These sessions were spaced over a period of 4 weeks. Skills retention was assessed in a summative objective structured clinical examination (OSCE) at the end of term, that is 6 months after the initial teaching session. A total of 32 students completed the study. With regard to suturing, OSCE performance was significantly better in group B than group A (81.9±13.1% vs 63.0±15.4%; P=0.001; Cohen's d=1.33). There was no significant OSCE performance difference in the two groups with regard to other learning objectives that were addressed in the end-of-term examination. Thus, the group difference was specific to suturing skills. This is the first study to demonstrate that in dental education, repeated testing produces more favourable skills retention than repeated practice. Test-enhanced learning might be a viable concept for skills retention in undergraduate dentistry education. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. ATXN2 trinucleotide repeat length correlates with risk of ALS.

    Science.gov (United States)

    Sproviero, William; Shatunov, Aleksey; Stahl, Daniel; Shoai, Maryam; van Rheenen, Wouter; Jones, Ashley R; Al-Sarraj, Safa; Andersen, Peter M; Bonini, Nancy M; Conforti, Francesca L; Van Damme, Philip; Daoud, Hussein; Del Mar Amador, Maria; Fogh, Isabella; Forzan, Monica; Gaastra, Ben; Gellera, Cinzia; Gitler, Aaron D; Hardy, John; Fratta, Pietro; La Bella, Vincenzo; Le Ber, Isabelle; Van Langenhove, Tim; Lattante, Serena; Lee, Yi-Chung; Malaspina, Andrea; Meininger, Vincent; Millecamps, Stéphanie; Orrell, Richard; Rademakers, Rosa; Robberecht, Wim; Rouleau, Guy; Ross, Owen A; Salachas, Francois; Sidle, Katie; Smith, Bradley N; Soong, Bing-Wen; Sorarù, Gianni; Stevanin, Giovanni; Kabashi, Edor; Troakes, Claire; van Broeckhoven, Christine; Veldink, Jan H; van den Berg, Leonard H; Shaw, Christopher E; Powell, John F; Al-Chalabi, Ammar

    2017-03-01

    We investigated a CAG trinucleotide repeat expansion in the ATXN2 gene in amyotrophic lateral sclerosis (ALS). Two new case-control studies, a British dataset of 1474 ALS cases and 567 controls, and a Dutch dataset of 1328 ALS cases and 691 controls were analyzed. In addition, to increase power, we systematically searched PubMed for case-control studies published after 1 August 2010 that investigated the association between ATXN2 intermediate repeats and ALS. We conducted a meta-analysis of the new and existing studies for the relative risks of ATXN2 intermediate repeat alleles of between 24 and 34 CAG trinucleotide repeats and ALS. There was an overall increased risk of ALS for those carrying intermediate sized trinucleotide repeat alleles (odds ratio 3.06 [95% confidence interval 2.37-3.94]; p = 6 × 10 -18 ), with an exponential relationship between repeat length and ALS risk for alleles of 29-32 repeats (R 2  = 0.91, p = 0.0002). No relationship was seen for repeat length and age of onset or survival. In contrast to trinucleotide repeat diseases, intermediate ATXN2 trinucleotide repeat expansion in ALS does not predict age of onset but does predict disease risk. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  16. Repeated pulsed x-ray emission equipment

    International Nuclear Information System (INIS)

    Terauchi, Hikaru; Iida, Satoshi

    1982-01-01

    X-ray diffraction technique has been applied to determine the spatial positions of atoms which compose a material, and it is needless to say that the technique is a fundamental means regardless of the fields of research. However, the application of X-ray diffraction to the research on physical properties has been so far limited to know the spatial positions of atoms or molecules under thermal equilibrium condition. The addition of time element to the conventional technique, that is, the analysis of material structure including the time-varying processes under non-equilibrium conditions, is considered to approach the elucidation of the essence of materials. The authors call this dynamic structural analysis. The authors have planned to analyze X-ray diffraction intensity which has the resolution of about 10 -8 s in the real time which is conjugate with energy. However, present pulsed X-ray sources are not suitable for diffraction experiment because the pulse width is too long or X-ray wavelength is too short. Accordingly, the authors have made for trial a pulsed X-ray source for diffraction experiment. Its specifications are: diode voltage (X-ray tube voltage) from 200 to 300 kV, diode current from 2 to 5 kA, pulse width of about 30ns, maximum repetition frequency 10 pps, and X-ray focus size of 2 mm diameter. One of the features of this source is the repeated generation of pulsed X-ray. This is the first trial in the world, and is indispensable to the dynamic structural analysis described above. The quality of the emitted X-ray is also written. (Wakatsuki, Y.)

  17. Repeated speech errors: evidence for learning.

    Science.gov (United States)

    Humphreys, Karin R; Menzies, Heather; Lake, Johanna K

    2010-11-01

    Three experiments elicited phonological speech errors using the SLIP procedure to investigate whether there is a tendency for speech errors on specific words to reoccur, and whether this effect can be attributed to implicit learning of an incorrect mapping from lemma to phonology for that word. In Experiment 1, when speakers made a phonological speech error in the study phase of the experiment (e.g. saying "beg pet" in place of "peg bet") they were over four times as likely to make an error on that same item several minutes later at test. A pseudo-error condition demonstrated that the effect is not simply due to a propensity for speakers to repeat phonological forms, regardless of whether or not they have been made in error. That is, saying "beg pet" correctly at study did not induce speakers to say "beg pet" in error instead of "peg bet" at test. Instead, the effect appeared to be due to learning of the error pathway. Experiment 2 replicated this finding, but also showed that after 48 h, errors made at study were no longer more likely to reoccur. As well as providing constraints on the longevity of the effect, this provides strong evidence that the error reoccurrences observed are not due to item-specific difficulty that leads individual speakers to make habitual mistakes on certain items. Experiment 3 showed that the diminishment of the effect 48 h later is not due to specific extra practice at the task. We discuss how these results fit in with a larger view of language as a dynamic system that is constantly adapting in response to experience. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Isolation of human simple repeat loci by hybridization selection.

    Science.gov (United States)

    Armour, J A; Neumann, R; Gobert, S; Jeffreys, A J

    1994-04-01

    We have isolated short tandem repeat arrays from the human genome, using a rapid method involving filter hybridization to enrich for tri- or tetranucleotide tandem repeats. About 30% of clones from the enriched library cross-hybridize with probes containing trimeric or tetrameric tandem arrays, facilitating the rapid isolation of large numbers of clones. In an initial analysis of 54 clones, 46 different tandem arrays were identified. Analysis of these tandem repeat loci by PCR showed that 24 were polymorphic in length; substantially higher levels of polymorphism were displayed by the tetrameric repeat loci isolated than by the trimeric repeats. Primary mapping of these loci by linkage analysis showed that they derive from 17 chromosomes, including the X chromosome. We anticipate the use of this strategy for the efficient isolation of tandem repeats from other sources of genomic DNA, including DNA from flow-sorted chromosomes, and from other species.

  19. Assembly of Repeat Content Using Next Generation Sequencing Data

    Energy Technology Data Exchange (ETDEWEB)

    labutti, Kurt; Kuo, Alan; Grigoriev, Igor; Copeland, Alex

    2014-03-17

    Repetitive organisms pose a challenge for short read assembly, and typically only unique regions and repeat regions shorter than the read length, can be accurately assembled. Recently, we have been investigating the use of Pacific Biosciences reads for de novo fungal assembly. We will present an assessment of the quality and degree of repeat reconstruction possible in a fungal genome using long read technology. We will also compare differences in assembly of repeat content using short read and long read technology.

  20. RTEL1 Inhibits Trinucleotide Repeat Expansions and Fragility

    OpenAIRE

    Aisling Frizzell; Jennifer H.G. Nguyen; Mark I.R. Petalcorin; Katherine D. Turner; Simon J. Boulton; Catherine H. Freudenreich; Robert S. Lahue

    2014-01-01

    SUMMARY Human RTEL1 is an essential, multifunctional helicase that maintains telomeres, regulates homologous recombination, and helps prevent bone marrow failure. Here, we show that RTEL1 also blocks trinucleotide repeat expansions, the causal mutation for 17 neurological diseases. Increased expansion frequencies of (CTG·CAG) repeats occurred in human cells following knockdown of RTEL1, but not the alternative helicase Fbh1, and purified RTEL1 efficiently unwound triplet repeat hairpins in vi...

  1. Misleading Children: Causal Attributions of Inconsistency under Repeated Questioning.

    Science.gov (United States)

    Siegal, Michael; And Others

    1988-01-01

    Four studies investigated whether inconsistency of children aged four to six on developmental tasks may reflect a misinterpretation of the experimenter's intent in communication under repeated questioning. (SKC)

  2. Coexistence of 3G repeaters with LTE base stations.

    Science.gov (United States)

    Yeo, Woon-Young; Lee, Sang-Min; Hwang, Gyung-Ho; Kim, Jae-Hoon

    2013-01-01

    Repeaters have been an attractive solution for mobile operators to upgrade their wireless networks at low cost and to extend network coverage effectively. Since the first LTE commercial deployment in 2009, many mobile operators have launched LTE networks by upgrading their 3G and legacy networks. Because all 3G frequency bands are shared with the frequency bands for LTE deployment and 3G mobile operators have an enormous number of repeaters, reusing 3G repeaters in LTE networks is definitely a practical and cost-efficient solution. However, 3G repeaters usually do not support spatial multiplexing with multiple antennas, and thus it is difficult to reuse them directly in LTE networks. In order to support spatial multiplexing of LTE, the role of 3G repeaters should be replaced with small LTE base stations or MIMO-capable repeaters. In this paper, a repeater network is proposed to reuse 3G repeaters in LTE deployment while still supporting multilayer transmission of LTE. Interestingly, the proposed network has a higher cluster throughput than an LTE network with MIMO-capable repeaters.

  3. R-loops: targets for nuclease cleavage and repeat instability.

    Science.gov (United States)

    Freudenreich, Catherine H

    2018-01-11

    R-loops form when transcribed RNA remains bound to its DNA template to form a stable RNA:DNA hybrid. Stable R-loops form when the RNA is purine-rich, and are further stabilized by DNA secondary structures on the non-template strand. Interestingly, many expandable and disease-causing repeat sequences form stable R-loops, and R-loops can contribute to repeat instability. Repeat expansions are responsible for multiple neurodegenerative diseases, including Huntington's disease, myotonic dystrophy, and several types of ataxias. Recently, it was found that R-loops at an expanded CAG/CTG repeat tract cause DNA breaks as well as repeat instability (Su and Freudenreich, Proc Natl Acad Sci USA 114, E8392-E8401, 2017). Two factors were identified as causing R-loop-dependent breaks at CAG/CTG tracts: deamination of cytosines and the MutLγ (Mlh1-Mlh3) endonuclease, defining two new mechanisms for how R-loops can generate DNA breaks (Su and Freudenreich, Proc Natl Acad Sci USA 114, E8392-E8401, 2017). Following R-loop-dependent nicking, base excision repair resulted in repeat instability. These results have implications for human repeat expansion diseases and provide a paradigm for how RNA:DNA hybrids can cause genome instability at structure-forming DNA sequences. This perspective summarizes mechanisms of R-loop-induced fragility at G-rich repeats and new links between DNA breaks and repeat instability.

  4. The repeatability of an intraoral dental colorimeter.

    Science.gov (United States)

    Tung, Francis F; Goldstein, Gary R; Jang, Sungkoo; Hittelman, Eugene

    2002-12-01

    Characterizing and reproducing color remain one of the most challenging aspects of dentistry. A relatively new intraoral colorimeter measures the color of natural teeth and metal-ceramic restorations and prints out a color recipe for the Vintage Halo Porcelain System. The reliability of the colorimeter is unknown. The purpose of this study was to evaluate the reliability of a contact dental colorimeter and to correlate the shade registered by the colorimeter with the shade selected by experienced clinicians. In part I of the study, 2 examiners (A and B) took 2 colorimeter measurements from the maxillary right central incisors of 11 subjects. The examiners were blinded to their own data and those of other investigators. The readings were repeated 3 weeks later with the same protocol. The Cronbach alpha reliability coefficient was used to analyze the collected data. In part II of the study, 2 experienced clinicians (examiners D and E) selected a shade from the classic Vita Lumin Vacuum shade guide for the maxillary right central incisors of the same 11 subjects. The clinicians were blinded to each other's selections and the colorimeter readings. It should be noted that the manufacturer of the colorimeter uses the terms shade, value, and hue to represent chroma, value, and hue, respectively, as defined in the Glossary of Prosthodontic Terms (J Prosthet Dent 1999;81:39-110). The reliability analysis results for each of the combined trials for shade, value, and hue were all >.94. The interexaminer reliability alpha values were >.9 for shade and value and.64 to.74 for hue. The interexaminer alpha represented the value range of each of 4 measurements. The intraexaminer reliability alpha values for shade, value, and hue were.99,.95, and.96 for examiner A and.99,.93, and.97 for examiner B, respectively. In part II of the study, the colorimeter agreed with itself 82% of the time, whereas clinicians agreed with each other on the selected shade 73% of the time. Selections made

  5. Cardiorespiratory Coordination in Repeated Maximal Exercise

    Directory of Open Access Journals (Sweden)

    Sergi Garcia-Retortillo

    2017-06-01

    Full Text Available Increases in cardiorespiratory coordination (CRC after training with no differences in performance and physiological variables have recently been reported using a principal component analysis approach. However, no research has yet evaluated the short-term effects of exercise on CRC. The aim of this study was to delineate the behavior of CRC under different physiological initial conditions produced by repeated maximal exercises. Fifteen participants performed 2 consecutive graded and maximal cycling tests. Test 1 was performed without any previous exercise, and Test 2 6 min after Test 1. Both tests started at 0 W and the workload was increased by 25 W/min in males and 20 W/min in females, until they were not able to maintain the prescribed cycling frequency of 70 rpm for more than 5 consecutive seconds. A principal component (PC analysis of selected cardiovascular and cardiorespiratory variables (expired fraction of O2, expired fraction of CO2, ventilation, systolic blood pressure, diastolic blood pressure, and heart rate was performed to evaluate the CRC defined by the number of PCs in both tests. In order to quantify the degree of coordination, the information entropy was calculated and the eigenvalues of the first PC (PC1 were compared between tests. Although no significant differences were found between the tests with respect to the performed maximal workload (Wmax, maximal oxygen consumption (VO2 max, or ventilatory threshold (VT, an increase in the number of PCs and/or a decrease of eigenvalues of PC1 (t = 2.95; p = 0.01; d = 1.08 was found in Test 2 compared to Test 1. Moreover, entropy was significantly higher (Z = 2.33; p = 0.02; d = 1.43 in the last test. In conclusion, despite the fact that no significant differences were observed in the conventionally explored maximal performance and physiological variables (Wmax, VO2 max, and VT between tests, a reduction of CRC was observed in Test 2. These results emphasize the interest of CRC

  6. Repeatability study of replicate crash tests: A signal analysis approach.

    Science.gov (United States)

    Seppi, Jeremy; Toczyski, Jacek; Crandall, Jeff R; Kerrigan, Jason

    2017-10-03

    To provide an objective basis on which to evaluate the repeatability of vehicle crash test methods, a recently developed signal analysis method was used to evaluate correlation of sensor time history data between replicate vehicle crash tests. The goal of this study was to evaluate the repeatability of rollover crash tests performed with the Dynamic Rollover Test System (DRoTS) relative to other vehicle crash test methods. Test data from DRoTS tests, deceleration rollover sled (DRS) tests, frontal crash tests, frontal offset crash tests, small overlap crash tests, small overlap impact (SOI) crash tests, and oblique crash tests were obtained from the literature and publicly available databases (the NHTSA vehicle database and the Insurance Institute for Highway Safety TechData) to examine crash test repeatability. Signal analysis of the DRoTS tests showed that force and deformation time histories had good to excellent repeatability, whereas vehicle kinematics showed only fair repeatability due to the vehicle mounting method for one pair of tests and slightly dissimilar mass properties (2.2%) in a second pair of tests. Relative to the DRS, the DRoTS tests showed very similar or higher levels of repeatability in nearly all vehicle kinematic data signals with the exception of global X' (road direction of travel) velocity and displacement due to the functionality of the DRoTS fixture. Based on the average overall scoring metric of the dominant acceleration, DRoTS was found to be as repeatable as all other crash tests analyzed. Vertical force measures showed good repeatability and were on par with frontal crash barrier forces. Dynamic deformation measures showed good to excellent repeatability as opposed to poor repeatability seen in SOI and oblique deformation measures. Using the signal analysis method as outlined in this article, the DRoTS was shown to have the same or better repeatability of crash test methods used in government regulatory and consumer evaluation test

  7. Repeat photography as a tool for detecting and monitoring historical ...

    African Journals Online (AJOL)

    Repeat photography was used to illustrate long-term changes occurring in coastal habitats in the Western Cape, South Africa. Hi storic images were sourced from books and theses, the public and subject specialists, and repeat photographs were then taken from the same perspectives. Visible changes could be categorised ...

  8. Towards accurate de novo assembly for genomes with repeats

    NARCIS (Netherlands)

    Bucur, Doina

    2017-01-01

    De novo genome assemblers designed for short k-mer length or using short raw reads are unlikely to recover complex features of the underlying genome, such as repeats hundreds of bases long. We implement a stochastic machine-learning method which obtains accurate assemblies with repeats and

  9. Analysis of CR1 Repeats in the Zebra Finch Genome

    Directory of Open Access Journals (Sweden)

    George E. Liu

    2013-06-01

    Full Text Available Most bird species have smaller genomes and fewer repeats than mammals. Chicken Repeat 1 (CR1 repeat is one of the most abundant families of repeats, ranging from ~133,000 to ~187,000 copies accounting for ~50 to ~80% of the interspersed repeats in the zebra finch and chicken genomes, respectively. CR1 repeats are believed to have arisen from the retrotransposition of a small number of master elements, which gave rise to multiple CR1 subfamilies in the chicken. In this study, we performed a global assessment of the divergence distributions, phylogenies, and consensus sequences of CR1 repeats in the zebra finch genome. We identified and validated 34 CR1 subfamilies and further analyzed the correlation between these subfamilies. We also discovered 4 novel lineage-specific CR1 subfamilies in the zebra finch when compared to the chicken genome. We built various evolutionary trees of these subfamilies and concluded that CR1 repeats may play an important role in reshaping the structure of bird genomes.

  10. The Effects of Repeated Experience on Children's Suggestibility.

    Science.gov (United States)

    Powell, Martine B.; Roberts, Kim P.; Ceci, Stephen J.; Hembrooke, Helene

    1999-01-01

    Examined effect of suggestive questions on 3- to 5-year-olds' and 6- to 8-year-olds' recall of the final occurrence of repeated event. Found that relative to reports of children experiencing single occurrence, reports about fixed items of repeated events were less contaminated by false suggestions. Children's age and delay of interview were…

  11. Impact of Inclusion or Exclusion of Repeaters on Test Equating

    Science.gov (United States)

    Puhan, Gautam

    2011-01-01

    This study examined the effect of including or excluding repeaters on the equating process and results. New forms of two tests were equated to their respective old forms using either all examinees or only the first timer examinees in the new form sample. Results showed that for both tests used in this study, including or excluding repeaters in the…

  12. Characteristics of persons with repeat syphilis - Idaho, 2011-2015.

    Science.gov (United States)

    Kassem, Ahmed M; Bartschi, Jared; Carter, Kris K

    2018-03-14

    During 2011-2015 in Idaho, 14 (7%) of 193 persons with early syphilis had repeat syphilis. Persons with repeat infections were more likely to have had secondary or early latent syphilis (P = 0.037) and be infected with HIV (P < 0.001) compared with those having one infection.

  13. Trinucleotide repeat microsatellite markers for Black Poplar (Populus nigra L.)

    NARCIS (Netherlands)

    Smulders, M.J.M.; Schoot, van der J.; Arens, P.; Vosman, B.

    2001-01-01

    Using an enrichment procedure, we have cloned microsatellite repeats from black poplar (Populus nigra L.) and developed primers for microsatellite marker analysis. Ten primer pairs, mostly for trinucleotide repeats, produced polymorphic fragments in P. nigra. Some of them also showed amplification

  14. Simple sequence repeat marker development and genetic mapping ...

    Indian Academy of Sciences (India)

    polymorphic SSR (simple sequence repeats) markers from libraries enriched for GA, CAA and AAT repeats, as well as 6 ... ers for quinoa was the development of a genetic linkage map ...... Weber J. L. 1990 Informativeness of human (dC-dA)n.

  15. Ocular surface sensitivity repeatability with Cochet-Bonnet esthesiometer.

    Science.gov (United States)

    Chao, Cecilia; Stapleton, Fiona; Badarudin, Ezailina; Golebiowski, Blanka

    2015-02-01

    To determine the repeatability of ocular surface threshold measurements using the Cochet-Bonnet esthesiometer on the same day and 3 months apart. Two separate studies were conducted to determine the repeatability of ocular surface threshold measurements made on the same day (n = 20 subjects) and 3 months apart (n = 29 subjects). The Cochet-Bonnet esthesiometer was used to measure corneal and inferior conjunctival thresholds using the ascending method of limits. The pressure exerted by the Cochet-Bonnet esthesiometer was determined using an analytical balance, for both the 0.08- and 0.12-mm-diameter filaments. This calibration was then used to convert filament length measurements to pressure. Repeatability was determined using a Bland and Altman analysis. The pressure exerted at each filament length differed between the two filament diameters. The measured pressure also differed from values provided by the manufacturer. Repeatability of threshold measurements at the central cornea was shown to be good, with better repeatability for same-day measurements (coefficient of repeatability [CoR] = ±0.23 g/mm²) than for those 3 months apart (CoR = ±0.52 g/mm²). Threshold measurements at the inferior conjunctiva, in contrast, were poorly repeatable (CoR = ±12.78 g/mm²). Cochet-Bonnet esthesiometry is repeatable when performed on the central cornea on the same day and 3 months apart, but this instrument is not recommended for conjunctival threshold measurements.

  16. Development of Repeated Sprint Ability in Talented Youth Basketball Players

    NARCIS (Netherlands)

    te Wierike, Sanne C. M.; de Jong, Mark C.; Tromp, Eveline J. Y.; Vuijk, Pieter J.; Lemmink, Koen A. P. M.; Malina, Robert M.; Elferink-Gemser, Marije T.; Visscher, Chris

    te Wierike, SCM, de Jong, MC, Tromp, EJY, Vuijk, PJ, Lemmink, KAPM, Malina, RM, Elferink-Gemser, MT, and Visscher, C. Development of repeated sprint ability in talented youth basketball players. J Strength Cond Res 28(4): 928-934, 2014-Factors affecting repeated sprint ability (RSA) were evaluated

  17. Large Polyglutamine Repeats Cause Muscle Degeneration in SCA17 Mice

    Directory of Open Access Journals (Sweden)

    Shanshan Huang

    2015-10-01

    Full Text Available In polyglutamine (polyQ diseases, large polyQ repeats cause juvenile cases with different symptoms than those of adult-onset patients, who carry smaller expanded polyQ repeats. The mechanisms behind the differential pathology mediated by different polyQ repeat lengths remain unknown. By studying knockin mouse models of spinal cerebellar ataxia-17 (SCA17, we found that a large polyQ (105 glutamines in the TATA-box-binding protein (TBP preferentially causes muscle degeneration and reduces the expression of muscle-specific genes. Direct expression of TBP with different polyQ repeats in mouse muscle revealed that muscle degeneration is mediated only by the large polyQ repeats. Different polyQ repeats differentially alter TBP’s interaction with neuronal and muscle-specific transcription factors. As a result, the large polyQ repeat decreases the association of MyoD with TBP and DNA promoters. Our findings suggest that specific alterations in protein interactions by large polyQ repeats may account for the unique pathology in juvenile polyQ diseases.

  18. Large Polyglutamine Repeats Cause Muscle Degeneration in SCA17 Mice

    Science.gov (United States)

    Huang, Shanshan; Yang, Su; Guo, Jifeng; Yan, Sen; Gaertig, Marta A.; Li, Shihua; Li, Xiao-Jiang

    2015-01-01

    SUMMARY In polyglutamine (polyQ) diseases, large polyQ repeats cause juvenile cases with different symptoms than adult-onset patients, who carry smaller expanded polyQ repeats. The mechanisms behind the differential pathology mediated by different polyQ repeat lengths remain unknown. By studying knock-in mouse models of spinal cerebellar ataxia-17 (SCA17), we found that a large polyQ (105 glutamines) in the TATA box-binding protein (TBP) preferentially causes muscle degeneration and reduces the expression of muscle-specific genes. Direct expression of TBP with different polyQ repeats in mouse muscle revealed that muscle degeneration is mediated only by the large polyQ repeats. Different polyQ repeats differentially alter TBP’s interaction with neuronal and muscle-specific transcription factors. As a result, the large polyQ repeat decreases the association of MyoD with TBP and DNA promoters. Our findings suggest that specific alterations in protein interactions by large polyQ repeats may account for the unique pathology in juvenile polyQ diseases. PMID:26387956

  19. Huntingtin gene repeat size variations affect risk of lifetime depression

    DEFF Research Database (Denmark)

    Gardiner, Sarah L.; van Belzen, Martine J.; Boogaard, Merel W.

    2017-01-01

    Huntington disease (HD) is a severe neuropsychiatric disorder caused by a cytosine-adenine-guanine (CAG) repeat expansion in the HTT gene. Although HD is frequently complicated by depression, it is still unknown to what extent common HTT CAG repeat size variations in the normal range could affect...

  20. Repeat profile analysis in an x-ray department

    International Nuclear Information System (INIS)

    Bassey, C.E.; Ojo, O.O.; Akpabio, I.

    1991-01-01

    The repeat profile of an x-ray department in a developing country was analysed monthly between July 1989 and June 1990. Results showed an average repeat rate of 3.7% for the period of study. The main causes of film repetition were: equipment fault, 33.9%; radiographer's fault, 27.4%; film fault, 19.3%; processing fault, 10.8% and patient's fault, 8.6%. The average repeat rate in the first 6 months of study reduced by 50% in the last 6 months. This was due to the effectiveness of implementation of corrective actions. The overall repeat rate was found to correlate well with both the equipment fault and radiographer's fault with correlation coefficients, r, of 0.94 and 0.91, respectively. It is expected that a further reduction in the repeat rate will be obtained after the introduction of quality assurance programmes. (author)

  1. Clinical oversight and the avoidance of repeat induced abortion.

    Science.gov (United States)

    Jacovetty, Erica L; Clare, Camille A; Squire, Mary-Beatrice; Kubal, Keshar P; Liou, Sherry; Inchiosa, Mario A

    2018-06-03

    To evaluate the impact of patient counseling, demographics, and contraceptive methods on repeat induced abortion in women attending family planning clinics. A retrospective chart review of repeat induced abortions was performed. The analysis included patients with an initial induced abortion obtained between January 1, 2001, and March 31, 2014, at New York City Health + Hospitals/Metropolitan. The duration of involvement in the family planning program, the use of contraceptive interventions, and 18 patient factors were analyzed for their correlation with the incidence of repeat induced abortions per year of follow-up. A decreased rate of repeat induced abortions was associated with a longer duration of clinical oversight (r 2 =0.449, Pabortions. By determining the patient characteristics that most influence repeat induced abortion rates, providers can best choose the most efficacious method of contraception available. © 2018 International Federation of Gynecology and Obstetrics.

  2. Selection pressure on human STR loci and its relevance in repeat expansion disease

    KAUST Repository

    Shimada, Makoto K.; Sanbonmatsu, Ryoko; Yamaguchi-Kabata, Yumi; Yamasaki, Chisato; Suzuki, Yoshiyuki; Chakraborty, Ranajit; Gojobori, Takashi; Imanishi, Tadashi

    2016-01-01

    Short Tandem Repeats (STRs) comprise repeats of one to several base pairs. Because of the high mutability due to strand slippage during DNA synthesis, rapid evolutionary change in the number of repeating units directly shapes the range of repeat

  3. Genus-specific protein binding to the large clusters of DNA repeats (short regularly spaced repeats) present in Sulfolobus genomes

    DEFF Research Database (Denmark)

    Peng, Xu; Brügger, Kim; Shen, Biao

    2003-01-01

    terminally modified and corresponds to SSO454, an open reading frame of previously unassigned function. It binds specifically to DNA fragments carrying double and single repeat sequences, binding on one side of the repeat structure, and producing an opening of the opposite side of the DNA structure. It also...... recognizes both main families of repeat sequences in S. solfataricus. The recombinant protein, expressed in Escherichia coli, showed the same binding properties to the SRSR repeat as the native one. The SSO454 protein exhibits a tripartite internal repeat structure which yields a good sequence match...... with a helix-turn-helix DNA-binding motif. Although this putative motif is shared by other archaeal proteins, orthologs of SSO454 were only detected in species within the Sulfolobus genus and in the closely related Acidianus genus. We infer that the genus-specific protein induces an opening of the structure...

  4. The molecular chemistry of diffuse and translucent clouds in the line-of-sight to Sgr B2: Absorption by simple organic and inorganic molecules in the GBT PRIMOS survey

    Science.gov (United States)

    Corby, J. F.; McGuire, B. A.; Herbst, E.; Remijan, A. J.

    2018-02-01

    The 1-50 GHz PRebiotic Interstellar MOlecular Survey (PRIMOS) contains 50 molecular absorption lines observed in clouds located in the line-of-sight to Sgr B2(N). The line-of-sight material is associated with diffuse and translucent clouds located in the Galactic center, bar, and spiral arms in the disk. We measured the column densities and estimate abundances, relative to H2, of 11 molecules and additional isotopologues observed in this material. We used absorption by optically thin transitions of c-C3H2 to estimate the molecular hydrogen columns, and argue that this method is preferable to more commonly used methods. We discuss the kinematic structure and abundance patterns of small molecules including the sulfur-bearing species CS, SO, CCS, H2CS, and HCS+; oxygen-bearing molecules OH, SiO, and H2CO; and simple hydrocarbon molecules c-C3H2, l-C3H, and l-C3H+. Finally, we discuss the implications of the observed chemistry for the structure of the gas and dust in the ISM. Highlighted results include the following. First, whereas gas in the disk has a molecular hydrogen fraction of 0.65, clouds on the outer edge of the Galactic bar and in or near the Galactic center have molecular fractions of 0.85 and >0.9, respectively. Second, we observe trends in isotope ratios with Galactocentric distance; while carbon and silicon show enhancement of the rare isotopes at low Galactocentric distances, sulfur exhibits no trend with Galactocentric distance. We also determine that the ratio of c-C3H2/c-H13CCCH provides a good estimate of the 12C/13C ratio, whereas H2CO/H213CO exhibits fractionation. Third, we report the presence of l-C3H+ in diffuse clouds for the first time. Finally, we suggest that CS has an enhanced abundance within higher density clumps of material in the disk, and therefore may be diagnostic of cloud conditions. If this holds, the diffuse clouds in the Galactic disk contain multiple embedded hyperdensities in a clumpy structure, and the density profile is not

  5. Environmental stress induces trinucleotide repeat mutagenesis in human cells.

    Science.gov (United States)

    Chatterjee, Nimrat; Lin, Yunfu; Santillan, Beatriz A; Yotnda, Patricia; Wilson, John H

    2015-03-24

    The dynamic mutability of microsatellite repeats is implicated in the modification of gene function and disease phenotype. Studies of the enhanced instability of long trinucleotide repeats (TNRs)-the cause of multiple human diseases-have revealed a remarkable complexity of mutagenic mechanisms. Here, we show that cold, heat, hypoxic, and oxidative stresses induce mutagenesis of a long CAG repeat tract in human cells. We show that stress-response factors mediate the stress-induced mutagenesis (SIM) of CAG repeats. We show further that SIM of CAG repeats does not involve mismatch repair, nucleotide excision repair, or transcription, processes that are known to promote TNR mutagenesis in other pathways of instability. Instead, we find that these stresses stimulate DNA rereplication, increasing the proportion of cells with >4 C-value (C) DNA content. Knockdown of the replication origin-licensing factor CDT1 eliminates both stress-induced rereplication and CAG repeat mutagenesis. In addition, direct induction of rereplication in the absence of stress also increases the proportion of cells with >4C DNA content and promotes repeat mutagenesis. Thus, environmental stress triggers a unique pathway for TNR mutagenesis that likely is mediated by DNA rereplication. This pathway may impact normal cells as they encounter stresses in their environment or during development or abnormal cells as they evolve metastatic potential.

  6. Dental Fear in Children with Repeated Tooth Injuries.

    Science.gov (United States)

    Negovetić Vranić, Dubravka; Ivančić Jokić, Nataša; Bakarčić, Danko; Carek, Andreja; Rotim, Željko; Verzak, Željko

    2016-06-01

    Tooth injuries are serious clinical conditions. Some children experience dental trauma only once, while others are more prone to repeated tooth injuries. Repeated dental trauma occurs in 19.4% to 30% of patients. Pain and dental trauma are the most common reasons for fear and anxiety. The main objective of this study was to investigate how dental trauma, as well as repeated dental trauma affects the occurrence and development of dental fear in children. The study was conducted on a random sample of 147 subjects (88 boys and 59 girls) aged 5-8 and 9-12 years. Subjects in both age groups were divided into subroups without dental trauma, with one dental trauma and with repeated dental trauma. The validated Children’s Fear Survey Schedule – Dental Subscale was used on fear assessment. Results showed that only 12.2% of children without trauma, 33.3% with one trauma and 51.7% with repeated trauma were not afraid of injection. Older children had a significantly lower fear of injections, touch of an unknown person, choking, going to the hospital and people in white uniforms. Dentist was not the cause of fear in 65.5% of patients with repeated trauma. With each repeated injury of teeth, the degree of their fear of dental treatment was lower.

  7. Oxidative stress adaptation with acute, chronic, and repeated stress.

    Science.gov (United States)

    Pickering, Andrew M; Vojtovich, Lesya; Tower, John; A Davies, Kelvin J

    2013-02-01

    Oxidative stress adaptation, or hormesis, is an important mechanism by which cells and organisms respond to, and cope with, environmental and physiological shifts in the level of oxidative stress. Most studies of oxidative stress adaption have been limited to adaptation induced by acute stress. In contrast, many if not most environmental and physiological stresses are either repeated or chronic. In this study we find that both cultured mammalian cells and the fruit fly Drosophila melanogaster are capable of adapting to chronic or repeated stress by upregulating protective systems, such as their proteasomal proteolytic capacity to remove oxidized proteins. Repeated stress adaptation resulted in significant extension of adaptive responses. Repeated stresses must occur at sufficiently long intervals, however (12-h or more for MEF cells and 7 days or more for flies), for adaptation to be successful, and the levels of both repeated and chronic stress must be lower than is optimal for adaptation to acute stress. Regrettably, regimens of adaptation to both repeated and chronic stress that were successful for short-term survival in Drosophila nevertheless also caused significant reductions in life span for the flies. Thus, although both repeated and chronic stress can be tolerated, they may result in a shorter life. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. ACCA phosphopeptide recognition by the BRCT repeats of BRCA1.

    Science.gov (United States)

    Ray, Hind; Moreau, Karen; Dizin, Eva; Callebaut, Isabelle; Venezia, Nicole Dalla

    2006-06-16

    The tumour suppressor gene BRCA1 encodes a 220 kDa protein that participates in multiple cellular processes. The BRCA1 protein contains a tandem of two BRCT repeats at its carboxy-terminal region. The majority of disease-associated BRCA1 mutations affect this region and provide to the BRCT repeats a central role in the BRCA1 tumour suppressor function. The BRCT repeats have been shown to mediate phospho-dependant protein-protein interactions. They recognize phosphorylated peptides using a recognition groove that spans both BRCT repeats. We previously identified an interaction between the tandem of BRCA1 BRCT repeats and ACCA, which was disrupted by germ line BRCA1 mutations that affect the BRCT repeats. We recently showed that BRCA1 modulates ACCA activity through its phospho-dependent binding to ACCA. To delineate the region of ACCA that is crucial for the regulation of its activity by BRCA1, we searched for potential phosphorylation sites in the ACCA sequence that might be recognized by the BRCA1 BRCT repeats. Using sequence analysis and structure modelling, we proposed the Ser1263 residue as the most favourable candidate among six residues, for recognition by the BRCA1 BRCT repeats. Using experimental approaches, such as GST pull-down assay with Bosc cells, we clearly showed that phosphorylation of only Ser1263 was essential for the interaction of ACCA with the BRCT repeats. We finally demonstrated by immunoprecipitation of ACCA in cells, that the whole BRCA1 protein interacts with ACCA when phosphorylated on Ser1263.

  9. Identification, variation and transcription of pneumococcal repeat sequences

    Science.gov (United States)

    2011-01-01

    Background Small interspersed repeats are commonly found in many bacterial chromosomes. Two families of repeats (BOX and RUP) have previously been identified in the genome of Streptococcus pneumoniae, a nasopharyngeal commensal and respiratory pathogen of humans. However, little is known about the role they play in pneumococcal genetics. Results Analysis of the genome of S. pneumoniae ATCC 700669 revealed the presence of a third repeat family, which we have named SPRITE. All three repeats are present at a reduced density in the genome of the closely related species S. mitis. However, they are almost entirely absent from all other streptococci, although a set of elements related to the pneumococcal BOX repeat was identified in the zoonotic pathogen S. suis. In conjunction with information regarding their distribution within the pneumococcal chromosome, this suggests that it is unlikely that these repeats are specialised sequences performing a particular role for the host, but rather that they constitute parasitic elements. However, comparing insertion sites between pneumococcal sequences indicates that they appear to transpose at a much lower rate than IS elements. Some large BOX elements in S. pneumoniae were found to encode open reading frames on both strands of the genome, whilst another was found to form a composite RNA structure with two T box riboswitches. In multiple cases, such BOX elements were demonstrated as being expressed using directional RNA-seq and RT-PCR. Conclusions BOX, RUP and SPRITE repeats appear to have proliferated extensively throughout the pneumococcal chromosome during the species' past, but novel insertions are currently occurring at a relatively slow rate. Through their extensive secondary structures, they seem likely to affect the expression of genes with which they are co-transcribed. Software for annotation of these repeats is freely available from ftp://ftp.sanger.ac.uk/pub/pathogens/strep_repeats/. PMID:21333003

  10. Reproducibility and Reliability of Repeated Quantitative Fluorescence Angiography

    DEFF Research Database (Denmark)

    Nerup, Nikolaj; Knudsen, Kristine Bach Korsholm; Ambrus, Rikard

    2017-01-01

    INTRODUCTION: When using fluorescence angiography (FA) in perioperative perfusion assessment, repeated measures with re-injections of fluorescent dye (ICG) may be required. However, repeated injections may cause saturation of dye in the tissue, exceeding the limit of fluorescence intensity...... that the camera can detect. As the emission of fluorescence is dependent of the excitatory light intensity, reduction of this may solve the problem. The aim of the present study was to investigate the reproducibility and reliability of repeated quantitative FA during a reduction of excitatory light....

  11. Pension Reform Act 2004 and its Controversies: Repeating or ...

    African Journals Online (AJOL)

    Pension Reform Act 2004 and its Controversies: Repeating or Learning from Past Mistakes? ... Journal of Research in National Development ... and discusses how the present pension reform will affect active employees when they retire.

  12. A study on the repeatability of ultrasonic testing data

    International Nuclear Information System (INIS)

    Yoshimura, Seiichi; Fukumoto, Hiroshi

    1980-01-01

    Reliability improvement of ultrasonic testing data is strongly desired in ultrasonic testing working of nuclear power plants. This paper deals with the problems of the testing by the manual and the remote control apparatus, and with the factors which influence the repeatability of ultrasonic testing data. Following results are found in it. (1) In the testing by the manual, working time and posture influence the repeatability of testing data. (2) Glycerin in suitable for the couplant in the respect of the repeatability of testing data. In the case of using machine oil, the pressure to the probe necessitates to be over 0.2 kg/cm 2 . (3) In the testing by the remote control apparatus, working time, working environment and defect position does not influence the repeatability of testing data. (author)

  13. Repeat Assessed Values Model for Housing Price Index

    Directory of Open Access Journals (Sweden)

    Carini Manuela

    2017-12-01

    Full Text Available This study proposes an innovative methodology, named Repeat Appraised Price Model (RAV, useful for determining the price index numbers for real estate markets and the corresponding index numbers of hedonic prices of main real estate characteristics in the case of a lack of data. The methodological approach proposed in this paper aims to appraise the time series of price index numbers. It integrates the principles of the method of repeat sales with the peculiarities of the Hedonic Price Method, overcoming the problem of an almost total absence of repeat sales for the same property in a given time range; on the other hand, the technique aims to overcome the limitation of the repeat sales technique concerning the inability to take into account the characteristics of individual properties.

  14. Repeated morphine treatment influences operant and spatial learning differentially

    Institute of Scientific and Technical Information of China (English)

    Mei-Na WANG; Zhi-Fang DONG; Jun CAO; Lin XU

    2006-01-01

    Objective To investigate whether repeated morphine exposure or prolonged withdrawal could influence operant and spatial learning differentially. Methods Animals were chronically treated with morphine or subjected to morphine withdrawal. Then, they were subjected to two kinds of learning: operant conditioning and spatial learning.Results The acquisition of both simple appetitive and cued operant learning was impaired after repeated morphine treatment. Withdrawal for 5 weeks alleviated the impairments. Single morphine exposure disrupted the retrieval of operant memory but had no effect on rats after 5-week withdrawal. Contrarily, neither chronic morphine exposure nor 5-week withdrawal influenced spatial learning task of the Morris water maze. Nevertheless, the retrieval of spatial memory was impaired by repeated morphine exposure but not by 5-week withdrawal. Conclusion These observations suggest that repeated morphine exposure can influence different types of learning at different aspects, implicating that the formation of opiate addiction may usurp memory mechanisms differentially.

  15. P-Scan provides accuracy and repeatability in ultrasonics

    International Nuclear Information System (INIS)

    Keys, R.L.

    1987-01-01

    The P-Scan (Projection image scanning technique) is an automated ultrasonic inspection technique, developed to overcome the problems with accuracy and repeatability experienced with manual ultrasonic systems. The equipment and its applications are described. (author)

  16. simple sequence repeat (SSR) markers in genetic analysis of

    African Journals Online (AJOL)

    Yomi

    2012-08-28

    1998). Cross- species amplification of soybean (Glycine max) simple sequence repeats (SSRs) within the genus and other legume genera: implications for the transferability of SSRs in plants. Mol. Biol. Evol. 15:1275-1287.

  17. Advantages and disadvantages : longitudinal vs. repeated cross-section surveys

    Science.gov (United States)

    1996-06-20

    The benefits of a longitudinal analysis over a repeated cross-sectional study include increased statistical power and the capability to estimate a greater range of conditional probabilities. With the Puget Sound Transportation Panel (PSTP), and any s...

  18. One way quantum repeaters with quantum Reed-Solomon codes

    OpenAIRE

    Muralidharan, Sreraman; Zou, Chang-Ling; Li, Linshu; Jiang, Liang

    2018-01-01

    We show that quantum Reed-Solomon codes constructed from classical Reed-Solomon codes can approach the capacity on the quantum erasure channel of $d$-level systems for large dimension $d$. We study the performance of one-way quantum repeaters with these codes and obtain a significant improvement in key generation rate compared to previously investigated encoding schemes with quantum parity codes and quantum polynomial codes. We also compare the three generation of quantum repeaters using quan...

  19. Learning, Teaching, and Turn Taking in the Repeated Assignment Game

    OpenAIRE

    Timothy N. Cason; Sau-Him Paul Lau; Vai-Lam Mui

    2011-01-01

    History-dependent strategies are often used to support cooperation in repeated game models. Using the indefinitely repeated common-pool resource assignment game and a perfect stranger experimental design, this paper reports novel evidence that players who have successfully used an efficiency-enhancing turn-taking strategy will teach other players in subsequent supergames to adopt this strategy. We find that subjects engage in turn taking frequently in both the Low Conflict and the High Confli...

  20. Relationship between quantum repeating devices and quantum seals

    International Nuclear Information System (INIS)

    He Guangping

    2009-01-01

    It is revealed that quantum repeating devices and quantum seals have a very close relationship, thus the theory in one field can be applied to the other. Consequently, it is shown that the fidelity bounds and optimality of quantum repeating devices for decoding quantum information can be violated when they are used for decoding classical information from quantum states and the security bounds for protocols sealing quantum data exist.

  1. Repeatability and reproducibility of decisions by latent fingerprint examiners.

    Directory of Open Access Journals (Sweden)

    Bradford T Ulery

    Full Text Available The interpretation of forensic fingerprint evidence relies on the expertise of latent print examiners. We tested latent print examiners on the extent to which they reached consistent decisions. This study assessed intra-examiner repeatability by retesting 72 examiners on comparisons of latent and exemplar fingerprints, after an interval of approximately seven months; each examiner was reassigned 25 image pairs for comparison, out of total pool of 744 image pairs. We compare these repeatability results with reproducibility (inter-examiner results derived from our previous study. Examiners repeated 89.1% of their individualization decisions, and 90.1% of their exclusion decisions; most of the changed decisions resulted in inconclusive decisions. Repeatability of comparison decisions (individualization, exclusion, inconclusive was 90.0% for mated pairs, and 85.9% for nonmated pairs. Repeatability and reproducibility were notably lower for comparisons assessed by the examiners as "difficult" than for "easy" or "moderate" comparisons, indicating that examiners' assessments of difficulty may be useful for quality assurance. No false positive errors were repeated (n = 4; 30% of false negative errors were repeated. One percent of latent value decisions were completely reversed (no value even for exclusion vs. of value for individualization. Most of the inter- and intra-examiner variability concerned whether the examiners considered the information available to be sufficient to reach a conclusion; this variability was concentrated on specific image pairs such that repeatability and reproducibility were very high on some comparisons and very low on others. Much of the variability appears to be due to making categorical decisions in borderline cases.

  2. Evaluation of Mammalian Interspersed Repeats to investigate the goat genome

    Directory of Open Access Journals (Sweden)

    P. Mariani

    2010-01-01

    Full Text Available Among the repeated sequences present in most eukaryotic genomes, SINEs (Short Interspersed Nuclear Elements are widely used to investigate evolution in the mammalian order (Buchanan et al., 1999. One family of these repetitive sequences, the MIR (Mammalian Interspersed Repeats; Jurka et al., 1995, is ubiquitous in all mammals.MIR elements are tRNA-derived SINEs and are identifiable by a conserved core region of about 70 nucleotides.

  3. A General Model for Repeated Audit Controls Using Monotone Subsampling

    OpenAIRE

    Raats, V.M.; van der Genugten, B.B.; Moors, J.J.A.

    2002-01-01

    In categorical repeated audit controls, fallible auditors classify sample elements in order to estimate the population fraction of elements in certain categories.To take possible misclassifications into account, subsequent checks are performed with a decreasing number of observations.In this paper a model is presented for a general repeated audit control system, where k subsequent auditors classify elements into r categories.Two different sub-sampling procedures will be discussed, named 'stra...

  4. Quantum key distribution with two-segment quantum repeaters

    Energy Technology Data Exchange (ETDEWEB)

    Kampermann, Hermann; Abruzzo, Silvestre; Bruss, Dagmar [Theoretische Physik III, Heinrich-Heine-Universitaet Duesseldorf (Germany)

    2014-07-01

    Quantum repeaters represent one possible way to achieve long-distance quantum key distribution. One way of improving the repeater rate and decreasing the memory coherence time is the usage of multiplexing. Motivated by the experimental fact that long-range connections are practically demanding, we extend the analysis of the quantum repeater multiplexing protocol to the case of short-range connections. We derive formulas for the repeater rate and we show that short-range connections lead to most of the benefits of a full-range multiplexing protocol. A less demanding QKD-protocol without quantum memories was recently introduced by Lo et al. We generalize this measurement-device-independent quantum key Distribution protocol to the scenario where the repeater Station contains also heralded quantum memories. We assume either single-photon sources or weak coherent pulse sources plus decay states. We show that it is possible to significantly outperform the original proposal, even in presence of decoherence of the quantum memory. We give formulas in terms of device imperfections i.e., the quantum bit error rate and the repeater rate.

  5. Repeated swim stress alters brain benzodiazepine receptors measured in vivo

    International Nuclear Information System (INIS)

    Weizman, R.; Weizman, A.; Kook, K.A.; Vocci, F.; Deutsch, S.I.; Paul, S.M.

    1989-01-01

    The effects of repeated swim stress on brain benzodiazepine receptors were examined in the mouse using both an in vivo and in vitro binding method. Specific in vivo binding of [ 3 H]Ro15-1788 to benzodiazepine receptors was decreased in the hippocampus, cerebral cortex, hypothalamus, midbrain and striatum after repeated swim stress (7 consecutive days of daily swim stress) when compared to nonstressed mice. In vivo benzodiazepine receptor binding was unaltered after repeated swim stress in the cerebellum and pons medulla. The stress-induced reduction in in vivo benzodiazepine receptor binding did not appear to be due to altered cerebral blood flow or to an alteration in benzodiazepine metabolism or biodistribution because there was no difference in [14C]iodoantipyrine distribution or whole brain concentrations of clonazepam after repeated swim stress. Saturation binding experiments revealed a change in both apparent maximal binding capacity and affinity after repeated swim stress. Moreover, a reduction in clonazepam's anticonvulsant potency was also observed after repeated swim stress [an increase in the ED50 dose for protection against pentylenetetrazol-induced seizures], although there was no difference in pentylenetetrazol-induced seizure threshold between the two groups. In contrast to the results obtained in vivo, no change in benzodiazepine receptor binding kinetics was observed using the in vitro binding method. These data suggest that environmental stress can alter the binding parameters of the benzodiazepine receptor and that the in vivo and in vitro binding methods can yield substantially different results

  6. Repeated swim stress alters brain benzodiazepine receptors measured in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Weizman, R.; Weizman, A.; Kook, K.A.; Vocci, F.; Deutsch, S.I.; Paul, S.M.

    1989-06-01

    The effects of repeated swim stress on brain benzodiazepine receptors were examined in the mouse using both an in vivo and in vitro binding method. Specific in vivo binding of (/sup 3/H)Ro15-1788 to benzodiazepine receptors was decreased in the hippocampus, cerebral cortex, hypothalamus, midbrain and striatum after repeated swim stress (7 consecutive days of daily swim stress) when compared to nonstressed mice. In vivo benzodiazepine receptor binding was unaltered after repeated swim stress in the cerebellum and pons medulla. The stress-induced reduction in in vivo benzodiazepine receptor binding did not appear to be due to altered cerebral blood flow or to an alteration in benzodiazepine metabolism or biodistribution because there was no difference in (14C)iodoantipyrine distribution or whole brain concentrations of clonazepam after repeated swim stress. Saturation binding experiments revealed a change in both apparent maximal binding capacity and affinity after repeated swim stress. Moreover, a reduction in clonazepam's anticonvulsant potency was also observed after repeated swim stress (an increase in the ED50 dose for protection against pentylenetetrazol-induced seizures), although there was no difference in pentylenetetrazol-induced seizure threshold between the two groups. In contrast to the results obtained in vivo, no change in benzodiazepine receptor binding kinetics was observed using the in vitro binding method. These data suggest that environmental stress can alter the binding parameters of the benzodiazepine receptor and that the in vivo and in vitro binding methods can yield substantially different results.

  7. Two tandemly repeated telomere-associated sequences in Nicotiana plumbaginifolia.

    Science.gov (United States)

    Chen, C M; Wang, C T; Wang, C J; Ho, C H; Kao, Y Y; Chen, C C

    1997-12-01

    Two tandemly repeated telomere-associated sequences, NP3R and NP4R, have been isolated from Nicotiana plumbaginifolia. The length of a repeating unit for NP3R and NP4R is 165 and 180 nucleotides respectively. The abundance of NP3R, NP4R and telomeric repeats is, respectively, 8.4 x 10(4), 6 x 10(3) and 1.5 x 10(6) copies per haploid genome of N. plumbaginifolia. Fluorescence in situ hybridization revealed that NP3R is located at the ends and/or in interstitial regions of all 10 chromosomes and NP4R on the terminal regions of three chromosomes in the haploid genome of N. plumbaginifolia. Sequence homology search revealed that not only are NP3R and NP4R homologous to HRS60 and GRS, respectively, two tandem repeats isolated from N. tabacum, but that NP3R and NP4R are also related to each other, suggesting that they originated from a common ancestral sequence. The role of these repeated sequences in chromosome healing is discussed based on the observation that two to three copies of a telomere-similar sequence were present in each repeating unit of NP3R and NP4R.

  8. Conceptual design of shallow ground repository (SGR)

    International Nuclear Information System (INIS)

    Roehl, J.L.; Franzen, H.R.

    1986-01-01

    A conceptual design to guide the development of the preliminary and final designs of a shallow ground waste disposal site for low and intermediate level radioactive wastes, complying with the Brazilian necessities, interpreted by Brazilian CNEN, is discussed. The general and specific criteria for the design of such installations, considering the reposing period, the isolation of personnel and environment, the operational activities, the characteristics of the site and of the subsoil and the set of necessary installations and services, are presented. An aboveground landfill, with concrete monoliths and concrete packages arranged in stacks disposed on an impermeable soil layer, is proposed. The disposed elements are covered by another impermeable soil stratum. (Author) [pt

  9. Startup program after SGR and power increase

    International Nuclear Information System (INIS)

    Krajnc, B.; Dudas, M.; Spiler, J.; Novsak, M.

    2000-01-01

    NPP Krsko replaced steam generators during the outage 2000. Parallel with the steam generator replacement all required systems modifications to accommodate new steam generators into the existing plant (upper feed,..) and support plant power increase of 6.3%, have been implemented. During the years 1997 - 2000 all the required licensing, technical analyses and systems verifications to support such plant changes have been completed. One of the activities within this effort was also the preparation of a detailed Plant Startup Program, which was subject of licensing review and approval process. An integrated plant startup program was then developed based on the plant startup test program, performed regularly during plant startup after refueling and above-mentioned Plant Startup Program. These additional tests defined by the Startup Test Program have been required due to new steam generators, steam generator replacement and related modifications, and power increase from previous 1882 MWt to 2000 MWt. During the preparation period, a startup team was established and procedures were written. All procedures sensitive to the operation were validated on the plant specific simulator. This paper presents more about the Startup Test Program, analysis of its implementation, the results of some key tests as well as the lessons learned. (author)

  10. SGR-76 gamma radiation level indicator

    International Nuclear Information System (INIS)

    Chubinskij-Nadezhdin, I.V.

    1978-01-01

    The design of a gamma-radiation level indicator is described; the instrument is part of a mobile radiometric laboratory (MRL). The design of the instrument permits gamma-radiation dose rates recording at 0.2-200 R/hr, and signals on gamma-background levels. The instrument has two separate threshold levels of signalling actuation. The light signalling at the first level is precautionary, and the sound signalling at the second level indicates the necessity of taking a decision as to whether or not the MRL can remain in the gamma-radiation field. Halogenic counters operating in a current mode are used as detectors. The basic error in recording the dose rate amounts to +-25%. Overall dimensions of the instrument 150x280x100 mm; weight less than 2.5 kg

  11. Germ-line CAG repeat instability causes extreme CAG repeat expansion with infantile-onset spinocerebellar ataxia type 2

    DEFF Research Database (Denmark)

    Vinther-Jensen, Tua; Ek, Jakob; Duno, Morten

    2013-01-01

    The spinocerebellar ataxias (SCA) are a genetically and clinically heterogeneous group of diseases, characterized by dominant inheritance, progressive cerebellar ataxia and diverse extracerebellar symptoms. A subgroup of the ataxias is caused by unstable CAG-repeat expansions in their respective ...... of paternal germ-line repeat sequence instability of the expanded SCA2 locus.European Journal of Human Genetics advance online publication, 10 October 2012; doi:10.1038/ejhg.2012.231....

  12. Reject/repeat analysis and the effect prior film viewing has on a department's reject/repeat rate

    International Nuclear Information System (INIS)

    Clark, P.A.; Hogg, P.

    2003-01-01

    Purpose: Achieving cost-effectiveness within the NHS is an old initiative but one that has again been highlighted by recent government policies (The New NHS-Modern and Dependable, Stationary Office, London, 1997). It has been reiterated that it is the responsibility of individual Trusts to devise means to provide such a service. Reject/repeat analyses have long been the primary tool used to assess the cost-effectiveness of radiography departments (Quality Assurance in Diagnostic Radiology, WHO, Geneva, 1982). This research paper examines an in-house initiative (viewing patients' previous films) commonly employed in other Health Trusts in order to reduce departmental repeat/reject rates. Method: Three hundred orthopaedic patients with hip, knee and ankle prostheses were included in a reject/repeat analysis. The aim was to investigate whether or not viewing patient's previous relevant radiographs would be advantageous to the practicing radiographer. This was done through an audit cycle consisting of two audit periods each lasting for 3 months. The primary audit period recorded the baseline repeat/reject rate, with the secondary audit period recording the repeat/reject rate under an experimental condition of viewing the relevant radiographs. Results: The baseline audit revealed repeat rates of 33% in orthopaedic patients with hip, knee and ankle prostheses. The availability of prior film viewing to the radiographer reduced this repeat rate to 10.6%. Conclusion: Prior film viewing dramatically reduced the department's repeat/reject rate by 22.4%. This provides scope for significant patient dose reductions as well as reducing departmental film expenses. This is an underestimated initiative and should be used appropriately in routine clinical practice

  13. Huntingtin gene repeat size variations affect risk of lifetime depression.

    Science.gov (United States)

    Gardiner, Sarah L; van Belzen, Martine J; Boogaard, Merel W; van Roon-Mom, Willeke M C; Rozing, Maarten P; van Hemert, Albert M; Smit, Johannes H; Beekman, Aartjan T F; van Grootheest, Gerard; Schoevers, Robert A; Oude Voshaar, Richard C; Roos, Raymund A C; Comijs, Hannie C; Penninx, Brenda W J H; van der Mast, Roos C; Aziz, N Ahmad

    2017-12-11

    Huntington disease (HD) is a severe neuropsychiatric disorder caused by a cytosine-adenine-guanine (CAG) repeat expansion in the HTT gene. Although HD is frequently complicated by depression, it is still unknown to what extent common HTT CAG repeat size variations in the normal range could affect depression risk in the general population. Using binary logistic regression, we assessed the association between HTT CAG repeat size and depression risk in two well-characterized Dutch cohorts─the Netherlands Study of Depression and Anxiety and the Netherlands Study of Depression in Older Persons─including 2165 depressed and 1058 non-depressed persons. In both cohorts, separately as well as combined, there was a significant non-linear association between the risk of lifetime depression and HTT CAG repeat size in which both relatively short and relatively large alleles were associated with an increased risk of depression (β = -0.292 and β = 0.006 for the linear and the quadratic term, respectively; both P < 0.01 after adjustment for the effects of sex, age, and education level). The odds of lifetime depression were lowest in persons with a HTT CAG repeat size of 21 (odds ratio: 0.71, 95% confidence interval: 0.52 to 0.98) compared to the average odds in the total cohort. In conclusion, lifetime depression risk was higher with both relatively short and relatively large HTT CAG repeat sizes in the normal range. Our study provides important proof-of-principle that repeat polymorphisms can act as hitherto unappreciated but complex genetic modifiers of depression.

  14. Intra-examiner repeatability and agreement in accommodative response measurements.

    Science.gov (United States)

    Antona, B; Sanchez, I; Barrio, A; Barra, F; Gonzalez, E

    2009-11-01

    Clinical measurement of the accommodative response (AR) identifies the focusing plane of a subject with respect to the accommodative target. To establish whether a significant change in AR has occurred, it is important to determine the repeatability of this measurement. This study had two aims: First, to determine the intraexaminer repeatability of AR measurements using four clinical methods: Nott retinoscopy, monocular estimate method (MEM) retinoscopy, binocular crossed cylinder test (BCC) and near autorefractometry. Second, to study the level of agreement between AR measurements obtained with the different methods. The AR of the right eye at one accommodative demand of 2.50 D (40 cm) was measured on two separate occasions in 61 visually normal subjects of mean age 19.7 years (range 18-32 years). The intraexaminer repeatability of the tests, and agreement between them, were estimated by the Bland-Altman method. We determined mean differences (MD) and the 95% limits of agreement [coefficient of repeatability (COR) and coefficient of agreement (COA)]. Nott retinoscopy and BCC offered the best repeatability, showing the lowest MD and narrowest 95% interval of agreement (Nott: -0.10 +/- 0.66 D, BCC: -0.05 +/- 0.75 D). The 95% limits of agreement for the four techniques were similar (COA = +/- 0.92 to +/-1.00 D) yet clinically significant, according to the expected values of the AR. The two dynamic retinoscopy techniques (Nott and MEM) had a better agreement (COA = +/-0.64 D) although this COA must be interpreted in the context of the low MEM repeatability (COR = +/-0.98 D). The best method of assessing AR was Nott retinoscopy. The BCC technique was also repeatable, and both are recommended as suitable methods for clinical use. Despite better agreement between MEM and Nott, agreement among the remaining methods was poor such that their interchangeable use in clinical practice is not recommended.

  15. RNA FISH for detecting expanded repeats in human diseases.

    Science.gov (United States)

    Urbanek, Martyna O; Krzyzosiak, Wlodzimierz J

    2016-04-01

    RNA fluorescence in situ hybridization (FISH) is a widely used technique for detecting transcripts in fixed cells and tissues. Many variants of RNA FISH have been proposed to increase signal strength, resolution and target specificity. The current variants of this technique facilitate the detection of the subcellular localization of transcripts at a single molecule level. Among the applications of RNA FISH are studies on nuclear RNA foci in diseases resulting from the expansion of tri-, tetra-, penta- and hexanucleotide repeats present in different single genes. The partial or complete retention of mutant transcripts forming RNA aggregates within the nucleoplasm has been shown in multiple cellular disease models and in the tissues of patients affected with these atypical mutations. Relevant diseases include, among others, myotonic dystrophy type 1 (DM1) with CUG repeats, Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3) with CAG repeats, fragile X-associated tremor/ataxia syndrome (FXTAS) with CGG repeats, myotonic dystrophy type 2 (DM2) with CCUG repeats, amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD) with GGGGCC repeats and spinocerebellar ataxia type 32 (SCA32) with GGCCUG. In this article, we summarize the results obtained with FISH to examine RNA nuclear inclusions. We provide a detailed protocol for detecting RNAs containing expanded CAG and CUG repeats in different cellular models, including fibroblasts, lymphoblasts, induced pluripotent stem cells and murine and human neuronal progenitors. We also present the results of the first single-molecule FISH application in a cellular model of polyglutamine disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. REPEATABILITY OF FRUIT QUALITY TRAITS OF CACTUS PEAR

    Directory of Open Access Journals (Sweden)

    VALTÂNIA XAVIER NUNES

    2017-12-01

    Full Text Available ABSTRACT Repeatability analysis has been used to study traits in several crops, assisting in the definition of the minimum number needed to evaluate genotypes more efficiently and with less time and resource consumption. So far, however, no repeatability studies on cactus pear have been found in the literature. The objective of this study was to determine the coefficient of repeatability for cactus pear fruits traits and the minimum number of evaluations (fruit that can provide acceptable accuracy for the prediction of the true value. The experiment was conducted at the Federal Institute of Bahia/Campus Guanambi, with 150 fruits collected from three municipalities in the state of Bahia. The coefficients of repeatability were estimated by the methods of analysis of variance, principal components based on the covariance (PCCV and correlation (PCC matrices, and structural analysis based on the correlation matrix (SA. The analysis of variance showed that, except for fruit diameter, the effect of the production site (municipality was significant for all traits evaluated. The PCCV method was proven the most suitable for studying the repeatability of quality traits of cactus pear fruits. Seven fruits were required to determine, with 90% confidence, the traits length, diameter, fruit firmness, skin thickness, number of seeds, fruit mass, bark mass, pulp mass, pH, titratable acidity, soluble solids, SS/AT ratio, and pulp yield.

  17. Incremental Dynamic Analysis of Koyna Dam under Repeated Ground Motions

    Science.gov (United States)

    Zainab Nik Azizan, Nik; Majid, Taksiah A.; Nazri, Fadzli Mohamed; Maity, Damodar; Abdullah, Junaidah

    2018-03-01

    This paper discovers the incremental dynamic analysis (IDA) of concrete gravity dam under single and repeated earthquake loadings to identify the limit state of the dam. Seven ground motions with horizontal and vertical direction as seismic input considered in the nonlinear dynamic analysis based on the real repeated earthquake in the worldwide. All the ground motions convert to respond spectrum and scaled according to the developed elastic respond spectrum in order to match the characteristic of the ground motion to the soil type. The scaled was depends on the fundamental period, T1 of the dam. The Koyna dam has been selected as a case study for the purpose of the analysis by assuming that no sliding and rigid foundation, has been estimated. IDA curves for Koyna dam developed for single and repeated ground motions and the performance level of the dam identifies. The IDA curve of repeated ground motion shown stiffer rather than single ground motion. The ultimate state displacement for a single event is 45.59mm and decreased to 39.33mm under repeated events which are decreased about 14%. This showed that the performance level of the dam based on seismic loadings depend on ground motion pattern.

  18. Flanking Variation Influences Rates of Stutter in Simple Repeats

    Directory of Open Access Journals (Sweden)

    August E. Woerner

    2017-11-01

    Full Text Available It has been posited that the longest uninterrupted stretch (LUS of tandem repeats, as defined by the number of exactly matching repeating motif units, is a better predictor of rates of stutter than the parental allele length (PAL. While there are cases where this hypothesis is likely correct, such as the 9.3 allele in the TH01 locus, there can be situations where it may not apply as well. For example, the PAL may capture flanking indel variations while remaining insensitive to polymorphisms in the repeat, and these haplotypic changes may impact the stutter rate. To address this, rates of stutter were contrasted against the LUS as well as the PAL on different flanking haplotypic backgrounds. This study shows that rates of stutter can vary substantially depending on the flanking haplotype, and while there are cases where the LUS is a better predictor of stutter than the PAL, examples to the contrary are apparent in commonly assayed forensic markers. Further, flanking variation that is 7 bp from the repeat region can impact rates of stutter. These findings suggest that non-proximal effects, such as DNA secondary structure, may be impacting the rates of stutter in common forensic short tandem repeat markers.

  19. A COMPARISON OF PAIRS FIGURE SKATERS IN REPEATED JUMPS

    Directory of Open Access Journals (Sweden)

    William A. Sands

    2012-03-01

    Full Text Available Trends in pairs figure skating have shown that increasingly difficult jumps have become an essential aspect of high-level performance, especially in the latter part of a competitive program. We compared a repeated jump power index in a 60 s repeated jump test to determine the relationship of repeated jump test to competitive rank and to measure 2D hip, knee, and ankle angles and angular velocities at 0, 20, 40, and 60 s. Eighteen National Team Pairs Figure Skaters performed a 60 s repeated jump test on a large switch-mat with timing of flight and ground durations and digital video recording. Each 60-s period was divided into 6, 10-s intervals, with power indexes (W/kg calculated for each 10-s interval. Power index by 10-s interval repeated measures ANOVAs (RMANOVA showed that males exceeded females at all intervals, and the highest power index interval was during 10 to 20 s for both sexes. RMANOVAs of angles and angular velocities showed main effects for time only. Power index and jumping techniques among figure skaters showed rapid and steady declines over the test duration. Power index can predict approximately 50% of competitive rank variance, and sex differences in jumping technique were rare

  20. Alanine repeats influence protein localization in splicing speckles and paraspeckles.

    Science.gov (United States)

    Chang, Shuo-Hsiu; Chang, Wei-Lun; Lu, Chia-Chen; Tarn, Woan-Yuh

    2014-12-16

    Mammalian splicing regulatory protein RNA-binding motif protein 4 (RBM4) has an alanine repeat-containing C-terminal domain (CAD) that confers both nuclear- and splicing speckle-targeting activities. Alanine-repeat expansion has pathological potential. Here we show that the alanine-repeat tracts influence the subnuclear targeting properties of the RBM4 CAD in cultured human cells. Notably, truncation of the alanine tracts redistributed a portion of RBM4 to paraspeckles. The alanine-deficient CAD was sufficient for paraspeckle targeting. On the other hand, alanine-repeat expansion reduced the mobility of RBM4 and impaired its splicing activity. We further took advantage of the putative coactivator activator (CoAA)-RBM4 conjoined splicing factor, CoAZ, to investigate the function of the CAD in subnuclear targeting. Transiently expressed CoAZ formed discrete nuclear foci that emerged and subsequently separated-fully or partially-from paraspeckles. Alanine-repeat expansion appeared to prevent CoAZ separation from paraspeckles, resulting in their complete colocalization. CoAZ foci were dynamic but, unlike paraspeckles, were resistant to RNase treatment. Our results indicate that the alanine-rich CAD, in conjunction with its conjoined RNA-binding domain(s), differentially influences the subnuclear localization and biogenesis of RBM4 and CoAZ. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  1. Design and analysis of communication protocols for quantum repeater networks

    International Nuclear Information System (INIS)

    Jones, Cody; Kim, Danny; Rakher, Matthew T; Ladd, Thaddeus D; Kwiat, Paul G

    2016-01-01

    We analyze how the performance of a quantum-repeater network depends on the protocol employed to distribute entanglement, and we find that the choice of repeater-to-repeater link protocol has a profound impact on entanglement-distribution rate as a function of hardware parameters. We develop numerical simulations of quantum networks using different protocols, where the repeater hardware is modeled in terms of key performance parameters, such as photon generation rate and collection efficiency. These parameters are motivated by recent experimental demonstrations in quantum dots, trapped ions, and nitrogen-vacancy centers in diamond. We find that a quantum-dot repeater with the newest protocol (‘MidpointSource’) delivers the highest entanglement-distribution rate for typical cases where there is low probability of establishing entanglement per transmission, and in some cases the rate is orders of magnitude higher than other schemes. Our simulation tools can be used to evaluate communication protocols as part of designing a large-scale quantum network. (paper)

  2. Electromyographic analysis of repeated bouts of eccentric exercise.

    Science.gov (United States)

    McHugh, M P; Connolly, D A; Eston, R G; Gartman, E J; Gleim, G W

    2001-03-01

    The repeated bout effect refers to the protective effect provided by a single bout of eccentric exercise against muscle damage from a similar subsequent bout. The aim of this study was to determine if the repeated bout was associated with an increase in motor unit activation relative to force production, an increased recruitment of slow-twitch motor units or increased motor unit synchronization. Surface electromyographic (EMG) signals were recorded from the hamstring muscles during two bouts of submaximal isokinetic (2.6 rad x s(-1)) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions separated by 2 weeks. The EMG per unit torque and median frequency were analysed. The initial bout of eccentric exercise resulted in strength loss, pain and muscle tenderness, while the repeated eccentric bout resulted in a slight increase in strength, no pain and no muscle tenderness (bout x time effects, P exercise. The EMG per unit torque and median frequency were not different between the initial and repeated bouts of eccentric exercise. The EMG per unit torque and median frequency increased during both bouts of eccentric exercise (P < 0.01) but did not change during either concentric bout. In conclusion, there was no evidence that the repeated bout effect was due to a neural adaptation.

  3. RTEL1 Inhibits Trinucleotide Repeat Expansions and Fragility

    Directory of Open Access Journals (Sweden)

    Aisling Frizzell

    2014-03-01

    Full Text Available Human RTEL1 is an essential, multifunctional helicase that maintains telomeres, regulates homologous recombination, and helps prevent bone marrow failure. Here, we show that RTEL1 also blocks trinucleotide repeat expansions, the causal mutation for 17 neurological diseases. Increased expansion frequencies of (CTG⋅CAG repeats occurred in human cells following knockdown of RTEL1, but not the alternative helicase Fbh1, and purified RTEL1 efficiently unwound triplet repeat hairpins in vitro. The expansion-blocking activity of RTEL1 also required Rad18 and HLTF, homologs of yeast Rad18 and Rad5. These findings are reminiscent of budding yeast Srs2, which inhibits expansions, unwinds hairpins, and prevents triplet-repeat-induced chromosome fragility. Accordingly, we found expansions and fragility were suppressed in yeast srs2 mutants expressing RTEL1, but not Fbh1. We propose that RTEL1 serves as a human analog of Srs2 to inhibit (CTG⋅CAG repeat expansions and fragility, likely by unwinding problematic hairpins.

  4. RTEL1 inhibits trinucleotide repeat expansions and fragility.

    Science.gov (United States)

    Frizzell, Aisling; Nguyen, Jennifer H G; Petalcorin, Mark I R; Turner, Katherine D; Boulton, Simon J; Freudenreich, Catherine H; Lahue, Robert S

    2014-03-13

    Human RTEL1 is an essential, multifunctional helicase that maintains telomeres, regulates homologous recombination, and helps prevent bone marrow failure. Here, we show that RTEL1 also blocks trinucleotide repeat expansions, the causal mutation for 17 neurological diseases. Increased expansion frequencies of (CTG⋅CAG) repeats occurred in human cells following knockdown of RTEL1, but not the alternative helicase Fbh1, and purified RTEL1 efficiently unwound triplet repeat hairpins in vitro. The expansion-blocking activity of RTEL1 also required Rad18 and HLTF, homologs of yeast Rad18 and Rad5. These findings are reminiscent of budding yeast Srs2, which inhibits expansions, unwinds hairpins, and prevents triplet-repeat-induced chromosome fragility. Accordingly, we found expansions and fragility were suppressed in yeast srs2 mutants expressing RTEL1, but not Fbh1. We propose that RTEL1 serves as a human analog of Srs2 to inhibit (CTG⋅CAG) repeat expansions and fragility, likely by unwinding problematic hairpins. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  5. The diversity and evolution of Wolbachia ankyrin repeat domain genes.

    Directory of Open Access Journals (Sweden)

    Stefanos Siozios

    Full Text Available Ankyrin repeat domain-encoding genes are common in the eukaryotic and viral domains of life, but they are rare in bacteria, the exception being a few obligate or facultative intracellular Proteobacteria species. Despite having a reduced genome, the arthropod strains of the alphaproteobacterium Wolbachia contain an unusually high number of ankyrin repeat domain-encoding genes ranging from 23 in wMel to 60 in wPip strain. This group of genes has attracted considerable attention for their astonishing large number as well as for the fact that ankyrin proteins are known to participate in protein-protein interactions, suggesting that they play a critical role in the molecular mechanism that determines host-Wolbachia symbiotic interactions. We present a comparative evolutionary analysis of the wMel-related ankyrin repeat domain-encoding genes present in different Drosophila-Wolbachia associations. Our results show that the ankyrin repeat domain-encoding genes change in size by expansion and contraction mediated by short directly repeated sequences. We provide examples of intra-genic recombination events and show that these genes are likely to be horizontally transferred between strains with the aid of bacteriophages. These results confirm previous findings that the Wolbachia genomes are evolutionary mosaics and illustrate the potential that these bacteria have to generate diversity in proteins potentially involved in the symbiotic interactions.

  6. Discrepancy variation of dinucleotide microsatellite repeats in eukaryotic genomes

    Directory of Open Access Journals (Sweden)

    HUAN GAO

    2009-01-01

    Full Text Available To address whether there are differences of variation among repeat motif types and among taxonomic groups, we present here an analysis of variation and correlation of dinucleotide microsatellite repeats in eukaryotic genomes. Ten taxonomic groups were compared, those being primates, mammalia (excluding primates and rodentia, rodentia, birds, fish, amphibians and reptiles, insects, molluscs, plants and fungi, respectively. The data used in the analysis is from the literature published in the Journal of Molecular Ecology Notes. Analysis of variation reveals that there are no significant differences between AC and AG repeat motif types. Moreover, the number of alleles correlates positively with the copy number in both AG and AC repeats. Similar conclusions can be obtained from each taxonomic group. These results strongly suggest that the increase of SSR variation is almost linear with the increase of the copy number of each repeat motif. As well, the results suggest that the variability of SSR in the genomes of low-ranking species seem to be more than that of high-ranking species, excluding primates and fungi.

  7. Instability of (CTGn•(CAGn trinucleotide repeats and DNA synthesis

    Directory of Open Access Journals (Sweden)

    Liu Guoqi

    2012-02-01

    Full Text Available Abstract Expansion of (CTGn•(CAGn trinucleotide repeat (TNR microsatellite sequences is the cause of more than a dozen human neurodegenerative diseases. (CTGn and (CAGn repeats form imperfectly base paired hairpins that tend to expand in vivo in a length-dependent manner. Yeast, mouse and human models confirm that (CTGn•(CAGn instability increases with repeat number, and implicate both DNA replication and DNA damage response mechanisms in (CTGn•(CAGn TNR expansion and contraction. Mutation and knockdown models that abrogate the expression of individual genes might also mask more subtle, cumulative effects of multiple additional pathways on (CTGn•(CAGn instability in whole animals. The identification of second site genetic modifiers may help to explain the variability of (CTGn•(CAGn TNR instability patterns between tissues and individuals, and offer opportunities for prognosis and treatment.

  8. Absence of bacterial resistance following repeat exposure to photodynamic therapy

    Science.gov (United States)

    Pedigo, Lisa A.; Gibbs, Aaron J.; Scott, Robert J.; Street, Cale N.

    2009-06-01

    The prevalence of antibiotic resistant bacteria necessitates exploration of alternative approaches to treat hospital and community acquired infections. The aim of this study was to determine whether bacterial pathogens develop resistance to antimicrobial photodynamic therapy (aPDT) during repeated sub-lethal challenge. Antibiotic sensitive and resistant strains of S. aureus and antibiotic sensitive E. coli were subjected to repeat PDT treatments using a methylene blue photosensitizer formulation and 670 nm illumination from a non-thermal diode laser. Parameters were adjusted such that kills were antibiotic resistance strains. Furthermore, repeated sub-lethal exposure does not induce resistance to subsequent PDT treatments. The absence of resistance formation represents a significant advantage of PDT over traditional antibiotics.

  9. Secondary immune response of rainbow trout following repeated immersion vaccination

    DEFF Research Database (Denmark)

    Jaafar, R. M.; Al-Jubury, A.; Chettri, J. K.

    2017-01-01

    Teleosts are able to raise a protective immune response, comprising both innate and adaptive elements, against various pathogens. This is the basis for a widespread use of vaccines, administered as injection or immersion, in the aquaculture industry. It has been described that repeated injection...... vaccination of fish raises a secondary immune response, consisting of rapid, accelerated and increased antibody reaction. This study reports how rainbow trout responds to repeated immersion vaccination against yersiniosis (ERM) caused by the bacterial pathogen Yersinia ruckeri. It was found that rainbow trout...... does not raise a classical secondary response following repeated immersion vaccination. Serum antibody titres were merely slightly increased even after three immunizations, using 30-s immersion into a bacterin consisting of formalin-inactivated Y. ruckeri (serotype O1, biotypes 1 and 2), performed over...

  10. Secondary immune response of rainbow trout following repeated immersion vaccination

    DEFF Research Database (Denmark)

    Jaafar, R. M.; Al-Jubury, Azmi; Chettri, Jiwan Kumar

    2018-01-01

    Teleosts are able to raise a protective immune response, comprising both innate and adaptive elements, against various pathogens. This is the basis for a widespread use of vaccines, administered as injection or immersion, in the aquaculture industry. It has been described that repeated injection...... vaccination of fish raises a secondary immune response, consisting of rapid, accelerated and increased antibody reaction. This study reports how rainbow trout responds to repeated immersion vaccination against yersiniosis (ERM) caused by the bacterial pathogen Yersinia ruckeri. It was found that rainbow trout...... does not raise a classical secondary response following repeated immersion vaccination. Serum antibody titres were merely slightly increased even after three immunizations, using 30-s immersion into a bacterin consisting of formalin-inactivated Y. ruckeri (serotype O1, biotypes 1 and 2), performed over...

  11. Gene conversion homogenizes the CMT1A paralogous repeats

    Directory of Open Access Journals (Sweden)

    Hurles Matthew E

    2001-12-01

    Full Text Available Abstract Background Non-allelic homologous recombination between paralogous repeats is increasingly being recognized as a major mechanism causing both pathogenic microdeletions and duplications, and structural polymorphism in the human genome. It has recently been shown empirically that gene conversion can homogenize such repeats, resulting in longer stretches of absolute identity that may increase the rate of non-allelic homologous recombination. Results Here, a statistical test to detect gene conversion between pairs of non-coding sequences is presented. It is shown that the 24 kb Charcot-Marie-Tooth type 1A paralogous repeats (CMT1A-REPs exhibit the imprint of gene conversion processes whilst control orthologous sequences do not. In addition, Monte Carlo simulations of the evolutionary divergence of the CMT1A-REPs, incorporating two alternative models for gene conversion, generate repeats that are statistically indistinguishable from the observed repeats. Bounds are placed on the rate of these conversion processes, with central values of 1.3 × 10-4 and 5.1 × 10-5 per generation for the alternative models. Conclusions This evidence presented here suggests that gene conversion may have played an important role in the evolution of the CMT1A-REP paralogous repeats. The rates of these processes are such that it is probable that homogenized CMT1A-REPs are polymorphic within modern populations. Gene conversion processes are similarly likely to play an important role in the evolution of other segmental duplications and may influence the rate of non-allelic homologous recombination between them.

  12. Low-Normal FMR1 CGG Repeat Length: Phenotypic Associations

    Directory of Open Access Journals (Sweden)

    Marsha eMailick

    2014-09-01

    Full Text Available This population-based study investigates genotype-phenotype correlations of low-normal CGG repeats in the fragile X mental retardation 1 (FMR1 gene. FMR1 plays an important role in brain development and function, and encodes FMRP (fragile X mental retardation protein, an RNA-binding protein that regulates protein synthesis impacting activity-dependent synaptic development and plasticity. Most past research has focused on CGG premutation expansions (41 to 200 CGG repeats and on fragile X syndrome (200+ CGG repeats, with considerably less attention on the other end of the spectrum of CGG repeats. Using existing data, older adults with 23 or fewer CGG repeats (2 SDs below the mean were compared with age-peers who have normal numbers of CGGs (24-40 with respect to cognition, mental health, cancer, and having children with disabilities. Men (n = 341 with an allele in the low-normal range and women (n = 46 with two low-normal alleles had significantly more difficulty with their memory and ability to solve day to day problems. Women with both FMR1 alleles in the low-normal category had significantly elevated odds of feeling that they need to drink more to get the same effect as in the past. These women also had two and one-half times the odds of having had breast cancer and four times the odds of uterine cancer. Men and women with low-normal CGGs had higher odds of having a child with a disability, either a developmental disability or a mental health condition. These findings are in line with the hypothesis that there is a need for tight neuronal homeostatic control mechanisms for optimal cognitive and behavioral functioning, and more generally that low numbers as well as high numbers of CGG repeats may be problematic for health.

  13. Repeat-aware modeling and correction of short read errors.

    Science.gov (United States)

    Yang, Xiao; Aluru, Srinivas; Dorman, Karin S

    2011-02-15

    High-throughput short read sequencing is revolutionizing genomics and systems biology research by enabling cost-effective deep coverage sequencing of genomes and transcriptomes. Error detection and correction are crucial to many short read sequencing applications including de novo genome sequencing, genome resequencing, and digital gene expression analysis. Short read error detection is typically carried out by counting the observed frequencies of kmers in reads and validating those with frequencies exceeding a threshold. In case of genomes with high repeat content, an erroneous kmer may be frequently observed if it has few nucleotide differences with valid kmers with multiple occurrences in the genome. Error detection and correction were mostly applied to genomes with low repeat content and this remains a challenging problem for genomes with high repeat content. We develop a statistical model and a computational method for error detection and correction in the presence of genomic repeats. We propose a method to infer genomic frequencies of kmers from their observed frequencies by analyzing the misread relationships among observed kmers. We also propose a method to estimate the threshold useful for validating kmers whose estimated genomic frequency exceeds the threshold. We demonstrate that superior error detection is achieved using these methods. Furthermore, we break away from the common assumption of uniformly distributed errors within a read, and provide a framework to model position-dependent error occurrence frequencies common to many short read platforms. Lastly, we achieve better error correction in genomes with high repeat content. The software is implemented in C++ and is freely available under GNU GPL3 license and Boost Software V1.0 license at "http://aluru-sun.ece.iastate.edu/doku.php?id = redeem". We introduce a statistical framework to model sequencing errors in next-generation reads, which led to promising results in detecting and correcting errors

  14. Repeat: a framework to assess empirical reproducibility in biomedical research

    Directory of Open Access Journals (Sweden)

    Leslie D. McIntosh

    2017-09-01

    Full Text Available Abstract Background The reproducibility of research is essential to rigorous science, yet significant concerns of the reliability and verifiability of biomedical research have been recently highlighted. Ongoing efforts across several domains of science and policy are working to clarify the fundamental characteristics of reproducibility and to enhance the transparency and accessibility of research. Methods The aim of the proceeding work is to develop an assessment tool operationalizing key concepts of research transparency in the biomedical domain, specifically for secondary biomedical data research using electronic health record data. The tool (RepeAT was developed through a multi-phase process that involved coding and extracting recommendations and practices for improving reproducibility from publications and reports across the biomedical and statistical sciences, field testing the instrument, and refining variables. Results RepeAT includes 119 unique variables grouped into five categories (research design and aim, database and data collection methods, data mining and data cleaning, data analysis, data sharing and documentation. Preliminary results in manually processing 40 scientific manuscripts indicate components of the proposed framework with strong inter-rater reliability, as well as directions for further research and refinement of RepeAT. Conclusions The use of RepeAT may allow the biomedical community to have a better understanding of the current practices of research transparency and accessibility among principal investigators. Common adoption of RepeAT may improve reporting of research practices and the availability of research outputs. Additionally, use of RepeAT will facilitate comparisons of research transparency and accessibility across domains and institutions.

  15. Layered Architectures for Quantum Computers and Quantum Repeaters

    Science.gov (United States)

    Jones, Nathan C.

    This chapter examines how to organize quantum computers and repeaters using a systematic framework known as layered architecture, where machine control is organized in layers associated with specialized tasks. The framework is flexible and could be used for analysis and comparison of quantum information systems. To demonstrate the design principles in practice, we develop architectures for quantum computers and quantum repeaters based on optically controlled quantum dots, showing how a myriad of technologies must operate synchronously to achieve fault-tolerance. Optical control makes information processing in this system very fast, scalable to large problem sizes, and extendable to quantum communication.

  16. Construction of a quantum repeater with linear optics

    International Nuclear Information System (INIS)

    Kok, Pieter; Williams, Colin P.; Dowling, Jonathan P.

    2003-01-01

    We study the mechanism and complexity of an efficient quantum repeater, employing double-photon guns, for long-distance optical quantum communication. The guns create polarization-entangled photon pairs on demand. One such source might be a semiconducter quantum dot, which has the distinct advantage over parametric down-conversion that the probability of creating a photon pair is close to 1, while the probability of creating multiple pairs vanishes. The swapping and purifying components are implemented by polarizing beam splitters and probabilistic optical controlled-NOT gates. We also show that the bottleneck in the efficiency of this repeater is due to detector losses

  17. Relationship between income and repeat criminal victimization in Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Justus

    2015-09-01

    Full Text Available This study analyzes the effect of income on repeat criminal victimization in Brazil using data from the 2009 National Household Sample Survey and its special supplement on victimization and access to justice. Two count-data models were estimated for four types of crime: theft, robbery, attempted theft/robbery, and physical assault. A positive nonlinear effect of income on repeat victimization for the three types of property crimes and a negative nonlinear effect of income on physical assault were observed.

  18. USGS Southwest Repeat Photography Collection: Kanab Creek, southern Utah and northern Arizona, 1872-2010

    Data.gov (United States)

    Department of the Interior — The USGS Southwest Repeat Photography Collection (‘Collection’), formerly named the Desert Laboratory Repeat Photography Collection, is now housed by the Southwest...

  19. Do repeated rumble strip hits improve driver alertness?

    NARCIS (Netherlands)

    Watling, C.N.; Akerstedt, T.; Kecklund, L.G.; Anund, A.

    2016-01-01

    Driving while sleepy is associated with increased crash risk. Rumble strips are designed to alert a sleepy or inattentive driver when they deviate outside their driving lane. The current study sought to examine the effects of repeated rumble strip hits on levels of physiological and subjective

  20. The repeatability of reproduction rate in the Tygerboek Merino Dock ...

    African Journals Online (AJOL)

    The repeatability of reproduction rate at 2 years or up to 3 years of age was investigated by regression methods considering subsequent reproduction ... would not improve Lb/Em in the current flock sUbstantially, whereas the proportion of ewes bearing multiples at 2 years was too low to supply replacement requirements.

  1. ATXN2 trinucleotide repeat length correlates with risk of ALS

    NARCIS (Netherlands)

    Sproviero, William; Shatunov, Aleksey; Stahl, Daniel; Shoai, Maryam; van Rheenen, Wouter; Jones, Ashley R; Al-Sarraj, Safa; Andersen, Peter M.; Bonini, Nancy M; Conforti, Francesca L; Van Damme, Philip; Daoud, Hussein; Del Mar Amador, Maria; Fogh, Isabella; Forzan, Monica; Gaastra, Ben; Gellera, Cinzia; Gitler, Aaron D; Hardy, John; Fratta, Pietro; La Bella, Vincenzo; Le Ber, Isabelle; Van Langenhove, Tim; Lattante, Serena; Lee, Yi-Chung; Malaspina, Andrea; Meininger, Vincent; Millecamps, Stéphanie; Orrell, Richard W; Rademakers, Rosa; Robberecht, Wim; Rouleau, Guy A.; Ross, Owen A; Salachas, Francois; Sidle, Katie; Smith, Bradley N; Soong, Bing-Wen; Sorarù, Gianni; Stevanin, Giovanni; Kabashi, Edor; Troakes, Claire; van Broeckhoven, Christine; Veldink, Jan H.; van den Berg, Leonard H.; Shaw, Christopher E; Powell, John F.; Al-Chalabi, Ammar

    2017-01-01

    We investigated a CAG trinucleotide repeat expansion in the ATXN2 gene in amyotrophic lateral sclerosis (ALS). Two new case-control studies, a British dataset of 1474 ALS cases and 567 controls, and a Dutch dataset of 1328 ALS cases and 691 controls were analyzed. In addition, to increase power, we

  2. Antithrombotic effect of repeated doses of the ethanolic extract of ...

    African Journals Online (AJOL)

    Antithrombotic effect of repeated doses of the ethanolic extract of local olive ( Olea europaea L.) leaves in rabbits. ... The incidence of thromboembolic diseases is increasing, and they are a major cause of mortality and morbidity worldwide. Mediterranean diet is known for its high content of olive products, especially olive oil, ...

  3. Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

    Science.gov (United States)

    Doğan, Aysun Şanal; Gürdal, Canan; Köylü, Mehmet Talay

    2018-04-01

    The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls. Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy). Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient. Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198) and gender (M/F: 4/29 vs. 8/32, p=0.366). Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90). The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

  4. Development of repeated sprint ability in talented youth basketball players

    NARCIS (Netherlands)

    te Wierike, Simon; Lemmink, Koen; de Jong, M.C.; Tromp, E.J.; Vuijk, P.J.; Malina, R.M.; Elferink-Gemser, Marije; Visscher, Chris

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were

  5. Repeated Recall and PKM? Maintain Fear Memories in Juvenile Rats

    Science.gov (United States)

    Oliver, Chicora F.; Kabitzke, Patricia; Serrano, Peter; Egan, Laura J.; Barr, Gordon A.; Shair, Harry N.; Wiedenmayer, Christoph

    2016-01-01

    We examined the neural substrates of fear memory formation and maintenance when repeated recall was used to prevent forgetting in young animals. In contrast to adult rats, juveniles failed to show contextual fear responses at 4 d post-fear conditioning. Reconsolidation sessions 3 and 6 d after conditioning restored contextual fear responses in…

  6. Complexity of repeated game model in electric power triopoly

    International Nuclear Information System (INIS)

    Ma Junhai; Ji Weizhuo

    2009-01-01

    According to the repeated game model in electric power duopoly, a triopoly outputs game model is presented. On the basis of some hypotheses, the dynamic characters are demonstrated with theoretical analysis and numerical simulations. The results show that the triopoly model is a chaotic system and it is better than the duopoly model in applications.

  7. Repeated oral administration of capsaicin increases anxiety-like ...

    Indian Academy of Sciences (India)

    This study was conducted to examine the psycho-emotional effects of repeated oral exposure to capsaicin, the principal active component of chili peppers. Each rat received 1 mL of 0.02% capsaicin into its oral cavity daily, and was subjected to behavioural tests following 10 daily administrations of capsaicin. Stereotypy ...

  8. Vital Signs – Preventing Repeat Teen Births

    Centers for Disease Control (CDC) Podcasts

    2013-04-02

    This podcast is based on the April 2013 CDC Vital Signs report, which discusses repeat teen births and ways teens, parents and guardians, health care providers, and communities can help prevent them.  Created: 4/2/2013 by Centers for Disease Control and Prevention (CDC).   Date Released: 4/2/2013.

  9. Y-Chromosome short tandem repeat, typing technology, locus ...

    African Journals Online (AJOL)

    Aghomotsegin

    2015-07-08

    Jul 8, 2015 ... Y-Chromosome short tandem repeat, typing technology, locus information and allele frequency in different population: A review. Muhanned Abdulhasan Kareem1, Ameera Omran Hussein2 and Imad Hadi Hameed2*. 1Babylon University, Centre of Environmental Research, Hilla City, Iraq. 2Department of ...

  10. Genetic Analysis of Eight X-Chromosomal Short Tandem Repeat ...

    African Journals Online (AJOL)

    X-Chromosome short tandem repeat (STR) typing can complement existing DNA profiling protocols and can also offer useful information in cases of complex kinship analysis. This is the first population study of 8 X-linked STRs in Iraq. The purpose of this work was to provide a basic data of allele and haplotype frequency for ...

  11. X-Chromosome short tandem repeat, advantages and typing ...

    African Journals Online (AJOL)

    Microsatellites of the X-chromosome have been increasingly studied in recent years as a useful tool in forensic analysis. This review describes some details of X-chromosomal short tandem repeat (STR) analysis. Among them are: microsatellites, amplification using polymerase chain reaction (PCR) of STRs, PCR product ...

  12. Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

    Directory of Open Access Journals (Sweden)

    Aysun Şanal Doğan

    2018-04-01

    Full Text Available Objectives: The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls. Materials and Methods: Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy. Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient. Results: Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198 and gender (M/F: 4/29 vs. 8/32, p=0.366. Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90. Conclusion: The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

  13. Repeated treatments of drooling with botulinum toxin B in neurology

    DEFF Research Database (Denmark)

    Møller, Eigild; Daugaard, Dorthe; Holm, Ole

    2015-01-01

    OBJECTIVES: To investigate efficacy, saliva flow, and composition in repeated BoNT-B treatments of drooling. MATERIALS AND METHODS: Seventeen neurological patients (median 66 years), referred for treatment of drooling participated in this observational study. Median total doses of 4000 units...

  14. Modeling and evaluating repeatability and reproducibility of ordinal classifications

    NARCIS (Netherlands)

    de Mast, J.; van Wieringen, W.N.

    2010-01-01

    This paper argues that currently available methods for the assessment of the repeatability and reproducibility of ordinal classifications are not satisfactory. The paper aims to study whether we can modify a class of models from Item Response Theory, well established for the study of the reliability

  15. The effectiveness of eye-closure in repeated interviews

    NARCIS (Netherlands)

    Vredeveldt, A.; Baddeley, A.D.; Hitch, G.J.

    2014-01-01

    Purpose Closing the eyes during recall can help witnesses remember more about a witnessed event. This study examined the effectiveness of eye-closure in a repeated recall paradigm with immediate free recall followed 1 week later by both free and cued recall. We examined whether eye-closure was more

  16. Analysis of unknown cause subarachnoid hemorrhage with repeated negative angiogram

    International Nuclear Information System (INIS)

    Fujii, Mutsumi; Takasato, Yoshio; Masaoka, Hiroyuki; Ohta, Yoshihisa; Hayakawa, Takanori; Honma, Masato

    2006-01-01

    Seven hundred and fifty five cases of acute non-traumatic subarachnoid hemorrhage (SAH) were admitted to the department of neurosurgery of our hospital from July, 1995 to March, 2004. In 555 patients cerebral angiography was conducted but initial angiography was negative in 30 patients. Except 10 general condition poor patients, in 20 initial angiogram-negative patients were undergone repeated angiography. The cause of SAH could not be demonstrated in 13 cases. The SAH in perimesencephalic and non-perimesencephalic cisturns was seen in 7 and 6 cases, respectively. Occipital and/or neck pain on admission was statistically more common among patients with perimesencephalic SAH than those with non-perimesencephalic SAH (p=0.029), and the prognosis of perimesencephalic SAH was good. We conclude that repeat angiography should not be recommended in patients with perimesencephalic SAH. Patients with non-perimesencephalic SAH had a higher rate of complication. In the non-perimesencephalic group, 3 patients developed hydrocephalus and 3 patients had vasospasm, which were found by repeated angiography. Therefore, repeated angiography is recommended for better clinical outcome by early detection and management of serious complications in this group of patients. (author)

  17. Insertion device and method for accurate and repeatable target insertion

    Science.gov (United States)

    Gubeli, III, Joseph F.; Shinn, Michelle D.; Bevins, Michael E.; Dillon-Townes, Lawrence; Neil, George R.

    2017-07-04

    The present invention discloses a device and a method for inserting and positioning a target within a free electron laser, particle accelerator, or other such device that generates or utilizes a beam of energy or particles. The system includes a three-point registration mechanism that insures angular and translational accuracy and repeatability of positioning upon multiple insertions within the same structure.

  18. Development of simple sequence repeat (SSR) markers that are ...

    African Journals Online (AJOL)

    Simple sequence repeats (SSRs) markers were developed through data mining of 3,803 expressed sequence tags (ESTs) previously published. A total of 144 di- to penta-type SSRs were identified and they were screened for polymorphism between two turnip cultivars, 'Tsuda' and 'Yurugi Akamaru'. Out of 90 EST-SSRs for ...

  19. Comparative effectiveness of inter-simple sequence repeat and ...

    African Journals Online (AJOL)

    A study to compare the effectiveness of inter-simple sequence repeats (ISSR) and randomly amplified polymorphic DNA (RAPD) profiling was carried out with a total of 65 DNA samples using 12 species of Indian Garcinia. ISSR and RAPD profiling were performed with 19 and 12 primers, respectively. ISSR markers ...

  20. Repfinder: Finding approximately repeated scene elements for image editing

    KAUST Repository

    Cheng, Ming-Ming

    2010-07-26

    Repeated elements are ubiquitous and abundant in both manmade and natural scenes. Editing such images while preserving the repetitions and their relations is nontrivial due to overlap, missing parts, deformation across instances, illumination variation, etc. Manually enforcing such relations is laborious and error-prone. We propose a novel framework where user scribbles are used to guide detection and extraction of such repeated elements. Our detection process, which is based on a novel boundary band method, robustly extracts the repetitions along with their deformations. The algorithm only considers the shape of the elements, and ignores similarity based on color, texture, etc. We then use topological sorting to establish a partial depth ordering of overlapping repeated instances. Missing parts on occluded instances are completed using information from other instances. The extracted repeated instances can then be seamlessly edited and manipulated for a variety of high level tasks that are otherwise difficult to perform. We demonstrate the versatility of our framework on a large set of inputs of varying complexity, showing applications to image rearrangement, edit transfer, deformation propagation, and instance replacement. © 2010 ACM.

  1. Non-radioactive detection of trinucleotide repeat size variability.

    Science.gov (United States)

    Tomé, Stéphanie; Nicole, Annie; Gomes-Pereira, Mario; Gourdon, Genevieve

    2014-03-06

    Many human diseases are associated with the abnormal expansion of unstable trinucleotide repeat sequences. The mechanisms of trinucleotide repeat size mutation have not been fully dissected, and their understanding must be grounded on the detailed analysis of repeat size distributions in human tissues and animal models. Small-pool PCR (SP-PCR) is a robust, highly sensitive and efficient PCR-based approach to assess the levels of repeat size variation, providing both quantitative and qualitative data. The method relies on the amplification of a very low number of DNA molecules, through sucessive dilution of a stock genomic DNA solution. Radioactive Southern blot hybridization is sensitive enough to detect SP-PCR products derived from single template molecules, separated by agarose gel electrophoresis and transferred onto DNA membranes. We describe a variation of the detection method that uses digoxigenin-labelled locked nucleic acid probes. This protocol keeps the sensitivity of the original method, while eliminating the health risks associated with the manipulation of radiolabelled probes, and the burden associated with their regulation, manipulation and waste disposal.

  2. Benefits of Repeated Book Readings in Children with SLI

    Science.gov (United States)

    Rohlfing, Katharina J.; Ceurremans, Josefa; Horst, Jessica S.

    2018-01-01

    In this pilot study, we ask whether repeated storybook reading is also beneficial for word learning in children diagnosed with specific language impairment (SLI). We compared 3-year-old German learning children diagnosed with SLI to typically developing children matched on age and socioeconomic status (SES). One week later, children with SLI…

  3. Repeatability of Objective Measurements of Linear Udder and Body ...

    African Journals Online (AJOL)

    The objective of this study was to estimates the repeatability of objective measurements on linear udder and body conformation traits and to evaluate the objectivity of the measurements in Friesian x Bunaji cows. Data from 50 (F1) Frisian X Bunaji cows collected between 2007 and 2008 at the Dairy Research Farm of the ...

  4. A General Model for Repeated Audit Controls Using Monotone Subsampling

    NARCIS (Netherlands)

    Raats, V.M.; van der Genugten, B.B.; Moors, J.J.A.

    2002-01-01

    In categorical repeated audit controls, fallible auditors classify sample elements in order to estimate the population fraction of elements in certain categories.To take possible misclassifications into account, subsequent checks are performed with a decreasing number of observations.In this paper a

  5. [Study on causes and treatment of repeated vulvovaginitis in girlhood].

    Science.gov (United States)

    Zhang, Di-kai; Li, Xiu-yun; Yang, Dong-zi; Kuang, Jian-quan

    2006-07-01

    To explore the causes and treatment of repeated vulvovaginitis in girlhood in order to improve its prevention and treatment. Fifty-one girls with repeated vulvovaginitis (age vulvovaginitis and 14 ones (27%) suffering from posterior recto-vaginal fistula with in 51 patients. Five girls (10%) were smitten with vulval ulcer and 3 ones (6%) had been were found with vaginal foreign bodies. One girl (2%) was smitten with adhesion of labia minora. The vaginal discharges taken from 21 girls were cultured. Seventeen cases found bacteria. The positive rate of bacteria culture in the 21 cases reached 81%, in which, E.coli accounted for 5 cases (24%), staphylococcus and streptococcus accounted for 3 cases (14%) respectively. Patients suffering from non-specific vulvovaginitis and vulval ulcer accepted external lotion, antibiotic ointment or combining with antibiotics. Patients suffering from posterior recto-vaginal fistula accepted fistulectomy. Three girls who found vaginal foreign bodies took out of foreign bodies by hysteroscope. Fifty-one girls all were cured after appropriate therapy. Vulvovaginitis is the most common gynecologic diagnosis in girlhood. The principal cause of repeated invasion is non-specific vulvovaginitis and the secondly one is posterior recto-vaginal fistula. It need overhaul during the diagnosis. It is very availability to use hysteroscopy and do bacteria culture + antibiotic sensitivity test for repeated pediatric vulvovaginitis.

  6. Reduction in gesture during the production of repeated references

    NARCIS (Netherlands)

    Hoetjes, M.W.; Koolen, R.M.F.; Goudbeek, M.B.; Krahmer, E.J.; Swerts, M.G.J.

    2015-01-01

    In dialogue, repeated references contain fewer words (which are also acoustically reduced) and fewer gestures than initial ones. In this paper, we describe three experiments studying to what extent gesture reduction is comparable to other forms of linguistic reduction. Since previous studies showed

  7. Participation behavior and social welfare in repeated task allocations

    NARCIS (Netherlands)

    Ye, Q.C.; Zhang, Y.

    2016-01-01

    Task allocation problems have focused on achieving one-shot optimality. In practice, many task allocation problems are of repeated nature, where the allocation outcome of previous rounds may influence the participation of agents in subsequent rounds, and consequently, the quality of the allocations

  8. Mononucleotide repeats are asymmetrically distributed in fungal genes

    NARCIS (Netherlands)

    Passel, van M.W.J.; Graaff, de L.H.

    2008-01-01

    ABSTRACT: BACKGROUND: Systematic analyses of sequence features have resulted in a better characterisation of the organisation of the genome. A previous study in prokaryotes on the distribution of sequence repeats, which are notoriously variable and can disrupt the reading frame in genes, showed that

  9. The breathing of webs under repeated partial edge loading

    Czech Academy of Sciences Publication Activity Database

    Škaloud, Miroslav; Zörnerová, Marie; Urushadze, Shota

    2012-01-01

    Roč. 40, č. 1 (2012), s. 463-468 E-ISSN 1877-7058. [Steel structures and bridges. Podbanske, 26.09.2012-28.09.2012] R&D Projects: GA ČR GA103/08/1340 Institutional support: RVO:68378297 Keywords : slender webs * breathing * fatigue limit state * design * repeated partial edge loading Subject RIV: JM - Building Engineering

  10. Increasing Positive Perceptions of Counseling: The Importance of Repeated Exposures

    Science.gov (United States)

    Kaplan, Scott A.; Vogel, David L.; Gentile, Douglas A.; Wade, Nathaniel G.

    2012-01-01

    This study assesses the effectiveness of repeated exposures to a video intervention based on the Elaboration Likelihood Model. The video was designed to increase help-seeking attitudes and perceptions of peer norms and to decrease the stigma associated with seeking counseling. Participants were 290 undergraduates who were randomly assigned to a…

  11. Monitoring selective logging in western Amazonia with repeat lidar flights

    Science.gov (United States)

    H.E. Andersen; S.E. Reutebuch; R.J. McGaughey; M.V.N. d' Oliveira; M. Keller

    2014-01-01

    The objective of this study was to test the use of repeat flight, airborne laser scanning data (lidar) for estimating changes associated with low-impact selective logging (approx. 10-15 m3 ha−1 = 5-7% of total standing volume harvested) in natural tropical forests in the Western Brazilian Amazon. Specifically, we investigated change in area...

  12. Suppressing non-periodically repeating disturbances in mechanical servo systems

    NARCIS (Netherlands)

    Tousain, R.L.; Boissy, J.C.; Norg, M.L.; Steinbuch, M.; Bosgra, O.H.

    1998-01-01

    Non-periodically repeating (NPR) disturbances are fixed-shape disturbances that occur randomly in time. We can provide a control system with the capability to suppress this type of disturbance by adding in parallel to the input of the nominal feedback controller a learning look-up-table based

  13. Study of simple sequence repeat (SSR) polymorphism for biotic ...

    African Journals Online (AJOL)

    home

    2013-10-02

    Oct 2, 2013 ... G. Siva Kumar1, K. Aruna Kumari1*, Ch. V. Durga Rani1, R. M. Sundaram2, S. Vanisree3, Md. ..... review by Jena and Mackill (2008) provided the list of .... repeat protein and is a member of a resistance gene cluster on rice.

  14. Development of repeated sprint ability in talented youth basketball players.

    NARCIS (Netherlands)

    Koen A.P.M. Lemmink; P.J. Vuijk; S.C. te Wierike; C. Visscher; M.T. Elferink-Gemser; M.C. de Jong; R.M. Malina; E.J. Tromp

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were

  15. Automated detection of repeated structures in building facades

    Directory of Open Access Journals (Sweden)

    M. Previtali

    2013-10-01

    Full Text Available Automatic identification of high-level repeated structures in 3D point clouds of building façades is crucial for applications like digitalization and building modelling. Indeed, in many architectural styles building façades are governed by arrangements of objects into repeated patterns. In particular, façades are generally designed as the repetition of some few basic objects organized into interlaced and\\or concatenated grid structures. Starting from this key observation, this paper presents an algorithm for Repeated Structure Detection (RSD in 3D point clouds of building façades. The presented methodology consists of three main phases. First, in the point cloud segmentation stage (i the building façade is decomposed into planar patches which are classified by means of some weak prior knowledge of urban buildings formulated in a classification tree. Secondly (ii, in the element clustering phase detected patches are grouped together by means of a similarity function and pairwise transformations between patches are computed. Eventually (iii, in the structure regularity estimation step the parameters of repeated grid patterns are calculated by using a Least- Squares optimization. Workability of the presented approach is tested using some real data from urban scenes.

  16. Determination of allele frequencies in nine short tandem repeat loci ...

    African Journals Online (AJOL)

    SERVER

    2008-04-17

    Apr 17, 2008 ... out the human genome. These loci are a rich source of highly polymorphic markers that may be detected using the polymerase chain reaction (PCR). PCR is a mimic of the normal cellular process of replication of DNA molecules. Each STR is distinguished by the number of times a sequence is repeated, ...

  17. Repfinder: Finding approximately repeated scene elements for image editing

    KAUST Repository

    Cheng, Ming-Ming; Zhang, Fanglue; Mitra, Niloy J.; Huang, Xiaolei; Hu, Shimin

    2010-01-01

    variation, etc. Manually enforcing such relations is laborious and error-prone. We propose a novel framework where user scribbles are used to guide detection and extraction of such repeated elements. Our detection process, which is based on a novel boundary

  18. Simple sequence repeat (SSR)-based genetic variability among ...

    African Journals Online (AJOL)

    The objective of this study was to compare if simple sequence repeat (SSR) markers could correctly identify peanut genotypes with difference in specific leaf weight (SLW) and relative water content (RWC). Four peanut genotypes and two water regimes (FC and 1/3 available water; 1/3 AW) were arranged in factorial ...

  19. Effect of repeated administration of Damiana on selected kidney ...

    African Journals Online (AJOL)

    The effect of repeated oral administration of Damiana, an aphrodisiac, on selected renal function indices of male rats for 20 days was investigated. Male rats were orally administered with appropriate volume corresponding to human therapeutic dose of 3.6mg/kg body weight of diamiana at 24hour intervals. The effects on ...

  20. Triplet repeat DNA structures and human genetic disease: dynamic ...

    Indian Academy of Sciences (India)

    Unknown

    formed at the loop-outs. [Sinden R R, Potaman V N, Oussatcheva E A, Pearson C E, Lyubchenko Y L and Shlyakhtenko L S 2002 Triplet repeat DNA structures .... 36–39. 40–121 Huntingtin/polyglutamine expansion. Spinocerebellar ataxia 1. SCA1. 6p23. (CAG)n. 6–44. –. 39–82 (pure) Ataxin-1/polyglutamine expansion.

  1. Prostate atypia: does repeat biopsy detect clinically significant prostate cancer?

    Science.gov (United States)

    Dorin, Ryan P; Wiener, Scott; Harris, Cory D; Wagner, Joseph R

    2015-05-01

    While the treatment pathway in response to benign or malignant prostate biopsies is well established, there is uncertainty regarding the risk of subsequently diagnosing prostate cancer when an initial diagnosis of prostate atypia is made. As such, we investigated the likelihood of a repeat biopsy diagnosing prostate cancer (PCa) in patients in which an initial biopsy diagnosed prostate atypia. We reviewed our prospectively maintained prostate biopsy database to identify patients who underwent a repeat prostate biopsy within one year of atypia (atypical small acinar proliferation; ASAP) diagnosis between November 1987 and March 2011. Patients with a history of PCa were excluded. Chart review identified patients who underwent radical prostatectomy (RP), radiotherapy (RT), or active surveillance (AS). For some analyses, patients were divided into two subgroups based on their date of service. Ten thousand seven hundred and twenty patients underwent 13,595 biopsies during November 1987-March 2011. Five hundred and sixty seven patients (5.3%) had ASAP on initial biopsy, and 287 (50.1%) of these patients underwent a repeat biopsy within one year. Of these, 122 (42.5%) were negative, 44 (15.3%) had atypia, 19 (6.6%) had prostatic intraepithelial neoplasia, and 102 (35.6%) contained PCa. Using modified Epstein's criteria, 27/53 (51%) patients with PCa on repeat biopsy were determined to have clinically significant tumors. 37 (36.3%) proceeded to RP, 25 (24.5%) underwent RT, and 40 (39.2%) received no immediate treatment. In patients who underwent surgery, Gleason grade on final pathology was upgraded in 11 (35.5%), and downgraded 1 (3.2%) patient. ASAP on initial biopsy was associated with a significant risk of PCa on repeat biopsy in patients who subsequently underwent definitive local therapy. Patients with ASAP should be counseled on the probability of harboring both clinically significant and insignificant prostate cancer. © 2015 Wiley Periodicals, Inc.

  2. Repeat workers' compensation claims: risk factors, costs and work disability

    Science.gov (United States)

    2011-01-01

    Background The objective of our study was to describe factors associated with repeat workers' compensation claims and to compare the work disability arising in workers with single and multiple compensation claims. Methods All initial injury claims lodged by persons of working age during a five year period (1996 to 2000) and any repeat claims were extracted from workers' compensation administrative data in the state of Victoria, Australia. Groups of workers with single and multiple claims were identified. Descriptive analysis of claims by affliction, bodily location, industry segment, occupation, employer and workplace was undertaken. Survival analysis determined the impact of these variables on the time between the claims. The economic impact and duration of work incapacity associated with initial and repeat claims was compared between groups. Results 37% of persons with an initial claim lodged a second claim. This group contained a significantly greater proportion of males, were younger and more likely to be employed in manual occupations and high-risk industries than those with single claims. 78% of repeat claims were for a second injury. Duration between the claims was shortest when the working conditions had not changed. The initial claims of repeat claimants resulted in significantly (p claims. Conclusions A substantial proportion of injured workers experience a second occupational injury or disease. These workers pose a greater economic burden than those with single claims, and also experience a substantially greater cumulative period of work disability. There is potential to reduce the social, health and economic burden of workplace injury by enacting prevention programs targeted at these workers. PMID:21696637

  3. Optimization of sequence alignment for simple sequence repeat regions

    Directory of Open Access Journals (Sweden)

    Ogbonnaya Francis C

    2011-07-01

    Full Text Available Abstract Background Microsatellites, or simple sequence repeats (SSRs, are tandemly repeated DNA sequences, including tandem copies of specific sequences no longer than six bases, that are distributed in the genome. SSR has been used as a molecular marker because it is easy to detect and is used in a range of applications, including genetic diversity, genome mapping, and marker assisted selection. It is also very mutable because of slipping in the DNA polymerase during DNA replication. This unique mutation increases the insertion/deletion (INDELs mutation frequency to a high ratio - more than other types of molecular markers such as single nucleotide polymorphism (SNPs. SNPs are more frequent than INDELs. Therefore, all designed algorithms for sequence alignment fit the vast majority of the genomic sequence without considering microsatellite regions, as unique sequences that require special consideration. The old algorithm is limited in its application because there are many overlaps between different repeat units which result in false evolutionary relationships. Findings To overcome the limitation of the aligning algorithm when dealing with SSR loci, a new algorithm was developed using PERL script with a Tk graphical interface. This program is based on aligning sequences after determining the repeated units first, and the last SSR nucleotides positions. This results in a shifting process according to the inserted repeated unit type. When studying the phylogenic relations before and after applying the new algorithm, many differences in the trees were obtained by increasing the SSR length and complexity. However, less distance between different linage had been observed after applying the new algorithm. Conclusions The new algorithm produces better estimates for aligning SSR loci because it reflects more reliable evolutionary relations between different linages. It reduces overlapping during SSR alignment, which results in a more realistic

  4. Conservative Sample Size Determination for Repeated Measures Analysis of Covariance.

    Science.gov (United States)

    Morgan, Timothy M; Case, L Douglas

    2013-07-05

    In the design of a randomized clinical trial with one pre and multiple post randomized assessments of the outcome variable, one needs to account for the repeated measures in determining the appropriate sample size. Unfortunately, one seldom has a good estimate of the variance of the outcome measure, let alone the correlations among the measurements over time. We show how sample sizes can be calculated by making conservative assumptions regarding the correlations for a variety of covariance structures. The most conservative choice for the correlation depends on the covariance structure and the number of repeated measures. In the absence of good estimates of the correlations, the sample size is often based on a two-sample t-test, making the 'ultra' conservative and unrealistic assumption that there are zero correlations between the baseline and follow-up measures while at the same time assuming there are perfect correlations between the follow-up measures. Compared to the case of taking a single measurement, substantial savings in sample size can be realized by accounting for the repeated measures, even with very conservative assumptions regarding the parameters of the assumed correlation matrix. Assuming compound symmetry, the sample size from the two-sample t-test calculation can be reduced at least 44%, 56%, and 61% for repeated measures analysis of covariance by taking 2, 3, and 4 follow-up measures, respectively. The results offer a rational basis for determining a fairly conservative, yet efficient, sample size for clinical trials with repeated measures and a baseline value.

  5. 30 CFR 250.522 - When do I have to repeat casing diagnostic testing?

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When do I have to repeat casing diagnostic... Operations Casing Pressure Management § 250.522 When do I have to repeat casing diagnostic testing? Casing diagnostic testing must be repeated according to the following table: When * * * you must repeat diagnostic...

  6. A high stability and repeatability electrochemical scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Zhigang; Wang, Jihao; Lu, Qingyou, E-mail: qxl@ustc.edu.cn [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China); Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hou, Yubin [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-12-15

    We present a home built electrochemical scanning tunneling microscope (ECSTM) with very high stability and repeatability. Its coarse approach is driven by a closely stacked piezo motor of GeckoDrive type with four rigid clamping points, which enhances the rigidity, compactness, and stability greatly. It can give high clarity atomic resolution images without sound and vibration isolations. Its drifting rates in XY and Z directions in solution are as low as 84 pm/min and 59 pm/min, respectively. In addition, repeatable coarse approaches in solution within 2 mm travel distance show a lateral deviation less than 50 nm. The gas environment can be well controlled to lower the evaporation rate of the cell, thus reducing the contamination and elongating the measurement time. Atomically resolved SO{sub 4}{sup 2−} image on Au (111) work electrode is demonstrated to show the performance of the ECSTM.

  7. A high stability and repeatability electrochemical scanning tunneling microscope.

    Science.gov (United States)

    Xia, Zhigang; Wang, Jihao; Hou, Yubin; Lu, Qingyou

    2014-12-01

    We present a home built electrochemical scanning tunneling microscope (ECSTM) with very high stability and repeatability. Its coarse approach is driven by a closely stacked piezo motor of GeckoDrive type with four rigid clamping points, which enhances the rigidity, compactness, and stability greatly. It can give high clarity atomic resolution images without sound and vibration isolations. Its drifting rates in XY and Z directions in solution are as low as 84 pm/min and 59 pm/min, respectively. In addition, repeatable coarse approaches in solution within 2 mm travel distance show a lateral deviation less than 50 nm. The gas environment can be well controlled to lower the evaporation rate of the cell, thus reducing the contamination and elongating the measurement time. Atomically resolved SO4(2-) image on Au (111) work electrode is demonstrated to show the performance of the ECSTM.

  8. Effect of Repeated Food Morsel Splitting on Jaw Muscle Control

    DEFF Research Database (Denmark)

    A, Kumar; Svensson, Krister G; Baad-Hansen, Lene

    2014-01-01

    Mastication is a complex motor task often initiated by splitting of the food morsel between the anterior teeth. Training of complex motor tasks has consistently been shown to trigger neuroplastic changes in corticomotor control and optimization of muscle function. It is not known if training...... and repeated food morsel splitting lead to changes in jaw muscle function. Objective: To investigate if repeated splitting of food morsels in participants with natural dentition changes the force and jaw muscle electromyographic (EMG) activity. Methods: Twenty healthy volunteers (mean age = 26.2 ± 3.9 years......) participated in a single one-hour session divided into six series. Each series consisted of ten trials of a standardized behavioral task (total of 60 trials). The behavioral task was to hold and split a food morsel (8 mm, 180 mg placebo tablet) placed on a bite force transducer with the anterior teeth...

  9. Debiasing egocentrism and optimism biases in repeated competitions

    Directory of Open Access Journals (Sweden)

    Jason P. Rose

    2012-11-01

    Full Text Available When judging their likelihood of success in competitive tasks, people tend to be overoptimistic for easy tasks and overpessimistic for hard tasks (the shared circumstance effect; SCE. Previous research has shown that feedback and experience from repeated-play competitions has a limited impact on SCEs. However, in this paper, we suggest that competitive situations, in which the shared difficulty or easiness of the task is more transparent, will be more amenable to debiasing via repeated play. Pairs of participants competed in, made predictions about, and received feedback on, multiple rounds of a throwing task involving both easy- and hard-to-aim objects. Participants initially showed robust SCEs, but they also showed a significant reduction in bias after only one round of feedback. These and other results support a more positive view (than suggested from past research on the potential for SCEs to be debiased through outcome feedback.

  10. On the crustal bias of repeat stations in Romania

    Directory of Open Access Journals (Sweden)

    Venera Dobrica

    2013-03-01

    Full Text Available A magnetic induction model has been applied to recordings obtained in 2010 during the field campaigns for geomagnetic measurements at the 26 repeat stations of the Romanian secular variation network. The model is based on the observation that a variable external magnetic field induces a response of the Earth's interior not only by electromagnetic induction, but also by magnetic induction in the magnetic rocks above the Curie temperature. The model computes coefficients of a linear relationship between recorded values of a certain geomagnetic element (X, Y, Z, or F at the repeat station and recorded X, Y, Z values at a reference station (in this case, SUA observatory. Coefficients depend on magnetic permeabilities of rocks beneath the station and stand as a proxy for the anomaly bias characterizing the site. Maps of the lateral variation of this type of information were obtained and discussed.

  11. Cognitive behavioural therapy halves the risk of repeated suicide attempts

    DEFF Research Database (Denmark)

    Gøtzsche, Peter C; Gøtzsche, Pernille K

    2017-01-01

    is excluded, the risk ratio becomes 0.61 (0.46-0.80) and the heterogeneity in the results disappears (I(2 )= 0%). Conclusions Cognitive behavioural therapy reduces not only repeated self-harm but also repeated suicide attempts. It should be the preferred treatment for all patients with depression.......Objective To study whether cognitive behavioural therapy decreases suicide attempts in people with previous suicide attempts. Design Systematic review and meta-analysis. Setting Randomised trials that compare cognitive behavioural therapy with treatment as usual. Participants Patients who had...... engaged in any type of suicide attempt in the six months prior to trial entry resulting in presentation to clinical services. Main outcome measure Suicide attempt. Results We included ten trials, eight from Cochrane reviews and two from our updated searches (1241 patients, 219 of whom had at least one new...

  12. PET functional volume delineation: a robustness and repeatability study

    International Nuclear Information System (INIS)

    Hatt, Mathieu; Cheze-le Rest, Catherine; Albarghach, Nidal; Pradier, Olivier; Visvikis, Dimitris

    2011-01-01

    Current state-of-the-art algorithms for functional uptake volume segmentation in PET imaging consist of threshold-based approaches, whose parameters often require specific optimization for a given scanner and associated reconstruction algorithms. Different advanced image segmentation approaches previously proposed and extensively validated, such as among others fuzzy C-means (FCM) clustering, or fuzzy locally adaptive bayesian (FLAB) algorithm have the potential to improve the robustness of functional uptake volume measurements. The objective of this study was to investigate robustness and repeatability with respect to various scanner models, reconstruction algorithms and acquisition conditions. Robustness was evaluated using a series of IEC phantom acquisitions carried out on different PET/CT scanners (Philips Gemini and Gemini Time-of-Flight, Siemens Biograph and GE Discovery LS) with their associated reconstruction algorithms (RAMLA, TF MLEM, OSEM). A range of acquisition parameters (contrast, duration) and reconstruction parameters (voxel size) were considered for each scanner model, and the repeatability of each method was evaluated on simulated and clinical tumours and compared to manual delineation. For all the scanner models, acquisition parameters and reconstruction algorithms considered, the FLAB algorithm demonstrated higher robustness in delineation of the spheres with low mean errors (10%) and variability (5%), with respect to threshold-based methodologies and FCM. The repeatability provided by all segmentation algorithms considered was very high with a negligible variability of <5% in comparison to that associated with manual delineation (5-35%). The use of advanced image segmentation algorithms may not only allow high accuracy as previously demonstrated, but also provide a robust and repeatable tool to aid physicians as an initial guess in determining functional volumes in PET. (orig.)

  13. Interstitial telomere-like repeats in the Arabidopsis thaliana genome.

    Science.gov (United States)

    Uchida, Wakana; Matsunaga, Sachihiro; Sugiyama, Ryuji; Kawano, Shigeyuki

    2002-02-01

    Eukaryotic chromosomal ends are protected by telomeres, which are thought to play an important role in ensuring the complete replication of chromosomes. On the other hand, non-functional telomere-like repeats in the interchromosomal regions (interstitial telomeric repeats; ITRs) have been reported in several eukaryotes. In this study, we identified eight ITRs in the Arabidopsis thaliana genome, each consisting of complete and degenerate 300- to 1200-bp sequences. The ITRs were grouped into three classes (class IA-B, class II, and class IIIA-E) based on the degeneracy of the telomeric repeats in ITRs. The telomeric repeats of the two ITRs in class I were conserved for the most part, whereas the single ITR in class II, and the five ITRs in class III were relatively degenerated. In addition, degenerate ITRs were surrounded by common sequences that shared 70-100% homology to each other; these are named ITR-adjacent sequences (IAS). Although the genomic regions around ITRs in class I lacked IAS, those around ITRs in class II contained IAS (IASa), and those around five ITRs in class III had nine types of IAS (IASb, c, d, e, f, g, h, i, and j). Ten IAS types in classes II and III showed no significant homology to each other. The chromosomal locations of ITRs and IAS were not category-related, but most of them were adjacent to, or part of, a centromere. These results show that the A. thaliana genome has undergone chromosomal rearrangements, such as end-fusions and segmental duplications.

  14. IEEE 802.3 Fiber Optic Inter-Repeater Link

    Science.gov (United States)

    Tarrant, Peter J.

    1987-01-01

    This paper describes the implementation of a fiber optic inter-repeater link (FOIRL), used for connecting two remote copper segments of an IEEE 802.3 local area network. The rationale for the design, the signalling used and the collision detection mechanism is discussed. The evolution of the draft international standard for the FOIRL and the concurrence amongst various manufacturers is also presented. Finally some examples of typical applications, highlighting the ease of installation, are given.

  15. Conformational properties of trinucleotide repeats associated with human neurodegenerative diseases

    Czech Academy of Sciences Publication Activity Database

    Vorlíčková, Michaela; Renčiuk, Daniel; Fojtík, Petr; Zemánek, Michal; Kejnovská, Iva

    2007-01-01

    Roč. 24, č. 6 (2007), s. 745 ISSN 0739-1102. [The 15th Conversation . 19.06.2007-23.06.2007, Albany] R&D Projects: GA AV ČR(CZ) IAA100040701; GA ČR(CZ) GA204/07/0057 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : DNA conformational properties * trinucleotide repeats * fragile X chromosome Subject RIV: BO - Biophysics

  16. REPEATABILITY OF THE FRENCH HIGHER VEGETATION TYPES ACCORDING

    Directory of Open Access Journals (Sweden)

    H. BRISSE

    1998-04-01

    Full Text Available Higher vegetation types are generally determined by successive approximations and defined by a common consent. Instead, they might be statistically determined and repeated, according to a numerical method called ‘socio-ecology’. This method deals only with floristical data, but gives them an ecological meaning by a previous calibration of the relations between plants, computed as ecological indices. It is applied to a pair of two homologous samples, each having 2.000 relevés and coming from the 60.000 relevés stored in the French data bank ‘Sophy’. Each sample covers the main ecological gradients of the bank, it defines a hierarchy of vegetation types and it explains half the peculiarity of a type with only 10 to 30 discriminant plants, out of the 5.000 plants observed in the relevés. Results : 1 The discriminant plants may characterize the vegetation types, including the higher ones, in a coherent and readable form. 2 In the two independent classifications, having different structures, the same vegetation types are repeated. They are the reciprocal nearest types, in the socio-ecological space. Though the two classifications have no one relevé in common, the repeated types have nearly the same discriminant plants. 3 At the highest level, two clear-cut main types show the difference between light and shadow. The same herbaceous discriminant plants, for a type, and the ligneous or sciaphilous ones, for the other, have similar fidelities and constancies in the two classifications. 4 Such a numerical agreement, instead of common consent, appears again in the sub-types, which remind the classical ones, but which are repeatable.

  17. Repeat immigration: A previously unobserved source of heterogeneity?

    Science.gov (United States)

    Aradhya, Siddartha; Scott, Kirk; Smith, Christopher D

    2017-07-01

    Register data allow for nuanced analyses of heterogeneities between sub-groups which are not observable in other data sources. One heterogeneity for which register data is particularly useful is in identifying unique migration histories of immigrant populations, a group of interest across disciplines. Years since migration is a commonly used measure of integration in studies seeking to understand the outcomes of immigrants. This study constructs detailed migration histories to test whether misclassified migrations may mask important heterogeneities. In doing so, we identify a previously understudied group of migrants called repeat immigrants, and show that they differ systematically from permanent immigrants. In addition, we quantify the degree to which migration information is misreported in the registers. The analysis is carried out in two steps. First, we estimate income trajectories for repeat immigrants and permanent immigrants to understand the degree to which they differ. Second, we test data validity by cross-referencing migration information with changes in income to determine whether there are inconsistencies indicating misreporting. From the first part of the analysis, the results indicate that repeat immigrants systematically differ from permanent immigrants in terms of income trajectories. Furthermore, income trajectories differ based on the way in which years since migration is calculated. The second part of the analysis suggests that misreported migration events, while present, are negligible. Repeat immigrants differ in terms of income trajectories, and may differ in terms of other outcomes as well. Furthermore, this study underlines that Swedish registers provide a reliable data source to analyze groups which are unidentifiable in other data sources.

  18. Perioperative Challenges in Repeat Bladder Exstrophy Repair - Case Report

    Directory of Open Access Journals (Sweden)

    Otu Enenyi Etta

    2015-07-01

    Full Text Available Bladder exstrophy is a rare congenital malformation. It presents as leakage of urine in the anterior abdominal wall following defects in midline anterior abdominal wall skin and bladder. We report the use of combined general anaesthesia and caudal epidural analgesia in a 4yr old boy for repeat bladder exstrophy repair. Problems of prolonged surgery and the challenges of pain and sedation management in the post operative period are discussed.

  19. Thermal, cardiac and adrenergic responses to repeated local cooling.

    Science.gov (United States)

    Janský, L; Matousková, E; Vávra, V; Vybíral, S; Janský, P; Jandová, D; Knízková, I; Kunc, P

    2006-01-01

    The aim of this study was to ascertain whether repeated local cooling induces the same or different adaptational responses as repeated whole body cooling. Repeated cooling of the legs (immersion into 12 degrees C water up to the knees for 30 min, 20 times during 4 weeks = local cold adaptation - LCA) attenuated the initial increase in heart rate and blood pressure currently observed in control subjects immersed in cold water up to the knees. After LCA the initial skin temperature decrease tended to be lower, indicating reduced vasoconstriction. Heart rate and systolic blood pressure appeared to be generally lower during rest and during the time course of cooling in LCA humans, when compared to controls. All these changes seem to indicate attenuation of the sympathetic tone. In contrast, the sustained skin temperature in different areas of the body (finger, palm, forearm, thigh, chest) appeared to be generally lower in LCA subjects than in controls (except for temperatures on the forehead). Plasma levels of catecholamines (measured 20 and 40 min after the onset of cooling) were also not influenced by local cold adaptation. Locally cold adapted subjects, when exposed to whole body cold water immersion test, showed no change in the threshold temperature for induction of cold thermogenesis. This indicates that the hypothermic type of cold adaptation, typically occurring after systemic cold adaptation, does not appear after local cold adaptation of the intensity used. It is concluded that in humans the cold adaptation due to repeated local cooling of legs induces different physiological changes than systemic cold adaptation.

  20. Distribution and Evolution of Yersinia Leucine-Rich Repeat Proteins

    Science.gov (United States)

    Hu, Yueming; Huang, He; Hui, Xinjie; Cheng, Xi; White, Aaron P.

    2016-01-01

    Leucine-rich repeat (LRR) proteins are widely distributed in bacteria, playing important roles in various protein-protein interaction processes. In Yersinia, the well-characterized type III secreted effector YopM also belongs to the LRR protein family and is encoded by virulence plasmids. However, little has been known about other LRR members encoded by Yersinia genomes or their evolution. In this study, the Yersinia LRR proteins were comprehensively screened, categorized, and compared. The LRR proteins encoded by chromosomes (LRR1 proteins) appeared to be more similar to each other and different from those encoded by plasmids (LRR2 proteins) with regard to repeat-unit length, amino acid composition profile, and gene expression regulation circuits. LRR1 proteins were also different from LRR2 proteins in that the LRR1 proteins contained an E3 ligase domain (NEL domain) in the C-terminal region or an NEL domain-encoding nucleotide relic in flanking genomic sequences. The LRR1 protein-encoding genes (LRR1 genes) varied dramatically and were categorized into 4 subgroups (a to d), with the LRR1a to -c genes evolving from the same ancestor and LRR1d genes evolving from another ancestor. The consensus and ancestor repeat-unit sequences were inferred for different LRR1 protein subgroups by use of a maximum parsimony modeling strategy. Structural modeling disclosed very similar repeat-unit structures between LRR1 and LRR2 proteins despite the different unit lengths and amino acid compositions. Structural constraints may serve as the driving force to explain the observed mutations in the LRR regions. This study suggests that there may be functional variation and lays the foundation for future experiments investigating the functions of the chromosomally encoded LRR proteins of Yersinia. PMID:27217422

  1. Perceived importance of attributes on hotel guests' repeat visit intentions

    OpenAIRE

    Emir, Oktay; Kozak, Metin

    2011-01-01

    Based on the empirical evidence in the related literature, we can emphasize that customer satisfaction and repeat patronage in the hotel industry has been well researched. Over the past two decades, many researchers as well as businesses have conducted surveys on visitors' satisfaction in order to measure customer perceptions of quality attributes of hotel or hospitality services. However, there is a lack of research paying attention to the empirical investigation of the self-perceived direct...

  2. Attempted suicide in Denmark. III. Assessment of repeated suicidal behaviour

    DEFF Research Database (Denmark)

    Wang, A G; Nielsen, B; Bille-Brahe, U

    1985-01-01

    , mostly in the first year. Ten patients committed suicide, half of them in the first 3 months after the interview, shortly after discharge from hospital. The majority of the repeaters were living alone, while those that committed suicide were mostly married women aged 50-60 years. Other characteristic...... poorly due, in particular, to low specificity. Future work will focus on objective risk factors, those indicated here and others, in order to establish an up-to-date background for assessment and management....

  3. Repeated wildfires alter forest recovery of mixed-conifer ecosystems.

    Science.gov (United States)

    Stevens-Rumann, Camille; Morgan, Penelope

    2016-09-01

    Most models project warmer and drier climates that will contribute to larger and more frequent wildfires. However, it remains unknown how repeated wildfires alter post-fire successional patterns and forest structure. Here, we test the hypothesis that the number of wildfires, as well as the order and severity of wildfire events interact to alter forest structure and vegetation recovery and implications for vegetation management. In 2014, we examined forest structure, composition, and tree regeneration in stands that burned 1-18 yr before a subsequent 2007 wildfire. Three important findings emerged: (1) Repeatedly burned forests had 15% less woody surface fuels and 31% lower tree seedling densities compared with forests that only experienced one recent wildfire. These repeatedly burned areas are recovering differently than sites burned once, which may lead to alternative ecosystem structure. (2) Order of burn severity (high followed by low severity compared with low followed by high severity) did influence forest characteristics. When low burn severity followed high, forests had 60% lower canopy closure and total basal area with 92% fewer tree seedlings than when high burn severity followed low. (3) Time between fires had no effect on most variables measured following the second fire except large woody fuels, canopy closure and tree seedling density. We conclude that repeatedly burned areas meet many vegetation management objectives of reduced fuel loads and moderate tree seedling densities. These differences in forest structure, composition, and tree regeneration have implications not only for the trajectories of these forests, but may reduce fire intensity and burn severity of subsequent wildfires and may be used in conjunction with future fire suppression tactics. © 2016 by the Ecological Society of America.

  4. Psychological and physiological responses following repeated peer death.

    Directory of Open Access Journals (Sweden)

    Judith Pizarro Andersen

    Full Text Available Undergraduates at a university in the United States were exposed - directly and indirectly - to 14 peer deaths during one academic year. We examined how individual and social factors were associated with psychological (e.g., anxiety, depression, somatization and physiological (i.e., cortisol distress responses following this unexpected and repeated experience with loss.Two to three months after the final peer death, respondents (N = 122, 61% female, 18-23 years, M = 20.13, SD = 1.14 reported prior adverse experiences, degree of closeness with the deceased, acute responses to the peer deaths, ongoing distress responses, social support, support seeking, and media viewing. A subset (n = 24 returned hair samples for evaluation of cortisol responses during the previous 3 months.Ongoing psychological distress was associated with a prior interpersonal trauma, b fewer social supports, and c media exposure to news of the deaths (p's25 p/mg compared to individuals with one or two prior bereavement experiences (who were, on average, within the normal range, 10 to 25 p/mg (p<.05. Only 8% of the sample utilized available university psychological or physical health resources and support groups.Limited research has examined the psychological and physiological impact of exposure to chronic, repeated peer loss, despite the fact that there are groups of individuals (e.g., police, military soldiers that routinely face such exposures. Prior adversity appears to play a role in shaping psychological and physiological responses to repeated loss. This topic warrants further research given the health implications of repeated loss for individuals in high-risk occupations and university settings.

  5. A repeat-until-success quantum computing scheme

    Energy Technology Data Exchange (ETDEWEB)

    Beige, A [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Lim, Y L [DSO National Laboratories, 20 Science Park Drive, Singapore 118230, Singapore (Singapore); Kwek, L C [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore (Singapore)

    2007-06-15

    Recently we proposed a hybrid architecture for quantum computing based on stationary and flying qubits: the repeat-until-success (RUS) quantum computing scheme. The scheme is largely implementation independent. Despite the incompleteness theorem for optical Bell-state measurements in any linear optics set-up, it allows for the implementation of a deterministic entangling gate between distant qubits. Here we review this distributed quantum computation scheme, which is ideally suited for integrated quantum computation and communication purposes.

  6. A repeat-until-success quantum computing scheme

    International Nuclear Information System (INIS)

    Beige, A; Lim, Y L; Kwek, L C

    2007-01-01

    Recently we proposed a hybrid architecture for quantum computing based on stationary and flying qubits: the repeat-until-success (RUS) quantum computing scheme. The scheme is largely implementation independent. Despite the incompleteness theorem for optical Bell-state measurements in any linear optics set-up, it allows for the implementation of a deterministic entangling gate between distant qubits. Here we review this distributed quantum computation scheme, which is ideally suited for integrated quantum computation and communication purposes

  7. Simple sequence repeat (SSR) markers are effective for identifying ...

    African Journals Online (AJOL)

    DNA was extracted from newly formed leaves and amplified using 21 simple sequence repeat (SSR) markers (NH001c, NH002b, NH005b, NH007b, NH008b, NH009b, NH011b, NH013b, NH012a, NH014a, NH015a, NH017a, KA4b, KA5, KA14, KA16, KB16, KU10, BGA35, BGT23b and HGA8b). The data was analyzed by ...

  8. Alu repeats as markers for forensic DNA analyses

    Energy Technology Data Exchange (ETDEWEB)

    Batzer, M.A.; Alegria-Hartman, M. [Lawrence Livermore National Lab., CA (United States); Kass, D.H. [Louisiana State Univ., New Orleans, LA (United States)] [and others

    1994-01-01

    The Human-Specific (HS) subfamily of Alu sequences is comprised of a group of 500 nearly identical members which are almost exclusively restricted to the human genome. Individual subfamily members share an average of 98.9% nucleotide identity with the HS subfamily consensus sequence, and have an average age of 2.8 million years. We have developed a Polymerase Chain Reaction (PCR) based assay using primers complementary to the 5 inch and 3 inch unique flanking DNA sequences from each HS Alu that allow the locus to be assayed for the presence or absence of the Alu repeat. The dimorphic HS Alu sequences probably inserted in the human genome after the radiation of modem humans (within the last 200,000-one million years) and represent a unique source of information for human population genetics and forensic DNA analyses. These sites can be developed into Dimorphic Alu Sequence Tagged Sites (DASTS) for the Human Genome Project. HS Alu family member insertions differ from other types of polymorphism (e.g. Variable Number of Tandem Repeat [VNTR] or Restriction Fragment Length Polymorphism [RFLP]) in that polymorphisms due to Alu insertions arise as a result of a unique event which has occurred only one time in the human population and spread through the population from that point. Therefore, individuals that share HS Alu repeats inherited these elements from a common ancestor. Most VNTR and RFLP polymorphisms may arise multiple times in parallel within a population.

  9. Measuring Repeatability of the Focus-variable Lenses

    Directory of Open Access Journals (Sweden)

    Jan Řezníček

    2014-12-01

    Full Text Available In the field of photogrammetry, the optical system, usually represented by the glass lens, is used for metric purposes. Therefore, the aberration characteristics of such a lens, inducing deviations from projective imaging, has to be well known. However, the most important property of the metric lens is the stability of its glass and mechanical elements, ensuring long-term reliability of the measured parameters. In case of a focus-variable lens, the repeatability of the lens setup is important as well. Lenses with a fixed focal length are usually considered as “fixed” though, in fact, most of them contain one or more movable glass elements, providing the focusing function. In cases where the lens is not equipped with fixing screws, the repeatability of the calibration parameters should be known. This paper derives simple mathematical formulas that can be used for measuring the repeatability of the focus-variable lenses, and gives a demonstrative example of such measuring. The given procedure has the advantage that only demanded parameters are estimated, hence, no unwanted correlations with the additional parameters exist. The test arrangement enables us to measure each demanded magnification of the optical system, which is important in close-range photogrammetry.

  10. Repeatability of nest morphology in African weaver birds.

    Science.gov (United States)

    Walsh, Patrick T; Hansell, Mike; Borello, Wendy D; Healy, Susan D

    2010-04-23

    It is generally assumed that birds build nests according to a genetic 'template', little influenced by learning or memory. One way to confirm the role of genetics in nest building is to assess the repeatability of nest morphology with repeated nest attempts. Solitary weaver birds, which build multiple nests in a single breeding season, are a useful group with which to do this. Here we show that repeatability of nest morphology was low, but significant, in male Southern Masked weaver birds and not significant in the Village weavers. The larger bodied Village weavers built larger nests than did Southern Masked weavers, but body size did not explain variation in Southern Masked weaver nest dimensions. Nests built by the same male in both species got shorter and lighter as more nests were constructed. While these data demonstrate the potential for a genetic component of variation in nest building in solitary weavers, it is also clear that there remains plenty of scope in both of these species for experience to shape nest construction.

  11. Repeat-containing protein effectors of plant-associated organisms

    Directory of Open Access Journals (Sweden)

    Carl H. Mesarich

    2015-10-01

    Full Text Available Many plant-associated organisms, including microbes, nematodes, and insects, deliver effector proteins into the apoplast, vascular tissue, or cell cytoplasm of their prospective hosts. These effectors function to promote colonization, typically by altering host physiology or by modulating host immune responses. The same effectors however, can also trigger host immunity in the presence of cognate host immune receptor proteins, and thus prevent colonization. To circumvent effector-triggered immunity, or to further enhance host colonization, plant-associated organisms often rely on adaptive effector evolution. In recent years, it has become increasingly apparent that several effectors of plant-associated organisms are repeat-containing proteins (RCPs that carry tandem or non-tandem arrays of an amino acid sequence or structural motif. In this review, we highlight the diverse roles that these repeat domains play in RCP effector function. We also draw attention to the potential role of these repeat domains in adaptive evolution with regards to RCP effector function and the evasion of effector-triggered immunity. The aim of this review is to increase the profile of RCP effectors from plant-associated organisms.

  12. The effect of repeated applanation on subsequent IOP measurements.

    Science.gov (United States)

    AlMubrad, Turki M; Ogbuehi, Kelechi C

    2008-11-01

    In studies aimed at assessing the accuracy and repeatability of non-contact tonometers, the order in which these tonometers and the Goldmann tonometer are used is usually randomised despite studies in the literature that demonstrate an ocular massage effect that occurs post-applanation but not after non-contact tonometry. The purpose of this study was to investigate the effect of repeated corneal applanation on subsequent assessments of IOP. Data were obtained from 65 left eyes of 65 young, oculovisual normals. Three sets of IOP measurements were obtained, one set with the Goldmann applanation tonometer and two with the Topcon CT80 non-contact tonometer (one set each before and after applanation with the Goldmann tonometer), in each one of two separate measurement sessions, one week apart. The average (and SD) IOP measured with the Goldmann tonometer in the first session (14.8+/-2.9 mmHg) did not vary significantly from the IOP measured with the non-contact tonometer (pre-applanation) in both sessions or with the average Goldmann IOP in the second session. The bias (mean difference +/- SD) between methods was 0.3+/-1.4 mmHg and 0.4+/-1.4 mmHg, respectively, for the first and second sessions, with the CT80 (pre-applanation) recording the higher IOP in both sessions. The within-session repeatability coefficients were +/-2.3 mmHg, +/-2.6 mmHg, +/-2.1 mmHg and +/-2.0 mmHg for the CT80 (pre-applanation) in the first and second sessions, and the Goldmann tonometer in the first and second sessions, respectively. Test-retest repeatability coefficients were +/-2.8 mmHg and +/-2.5 mmHg for the CT80 (pre-applanation) and the Goldmann tonometer respectively. Post-applanation with the Goldmann tonometer, there was a statistically significant (pcontact tonometer in both sessions. These results suggest that repeated corneal applanation leads to a statistically significant reduction in IOP on subsequent measurements.

  13. StaRProtein, A Web Server for Prediction of the Stability of Repeat Proteins

    Science.gov (United States)

    Xu, Yongtao; Zhou, Xu; Huang, Meilan

    2015-01-01

    Repeat proteins have become increasingly important due to their capability to bind to almost any proteins and the potential as alternative therapy to monoclonal antibodies. In the past decade repeat proteins have been designed to mediate specific protein-protein interactions. The tetratricopeptide and ankyrin repeat proteins are two classes of helical repeat proteins that form different binding pockets to accommodate various partners. It is important to understand the factors that define folding and stability of repeat proteins in order to prioritize the most stable designed repeat proteins to further explore their potential binding affinities. Here we developed distance-dependant statistical potentials using two classes of alpha-helical repeat proteins, tetratricopeptide and ankyrin repeat proteins respectively, and evaluated their efficiency in predicting the stability of repeat proteins. We demonstrated that the repeat-specific statistical potentials based on these two classes of repeat proteins showed paramount accuracy compared with non-specific statistical potentials in: 1) discriminate correct vs. incorrect models 2) rank the stability of designed repeat proteins. In particular, the statistical scores correlate closely with the equilibrium unfolding free energies of repeat proteins and therefore would serve as a novel tool in quickly prioritizing the designed repeat proteins with high stability. StaRProtein web server was developed for predicting the stability of repeat proteins. PMID:25807112

  14. Alu repeats as markers for human population genetics

    Energy Technology Data Exchange (ETDEWEB)

    Batzer, M.A.; Alegria-Hartman, M. [Lawrence Livermore National Lab., CA (United States); Bazan, H. [Louisiana State Univ., New Orleans, LA (United States). Medical Center] [and others

    1993-09-01

    The Human-Specific (HS) subfamily of Alu sequences is comprised of a group of 500 nearly identical members which are almost exclusively restricted to the human genome. Individual subfamily members share an average of 97.9% nucleotide identity with each other and an average of 98.9% nucleotide identity with the HS subfamily consensus sequence. HS Alu family members are thought to be derived from a single source ``master`` gene, and have an average age of 2.8 million years. We have developed a Polymerase Chain Reaction (PCR) based assay using primers complementary to the 5 in. and 3 in. unique flanking DNA sequences from each HS Alu that allows the locus to be assayed for the presence or absence of an Alu repeat. Individual HS Alu sequences were found to be either monomorphic or dimorphic for the presence or absence of each repeat. The monomorphic HS Alu family members inserted in the human genome after the human/great ape divergence (which is thought to have occurred 4--6 million years ago), but before the radiation of modem man. The dimorphic HS Alu sequences inserted in the human genome after the radiation of modem man (within the last 200,000-one million years) and represent a unique source of information for human population genetics and forensic DNA analyses. These sites can be developed into Dimorphic Alu Sequence Tagged Sites (DASTS) for the Human Genome Project as well. HS Alu family member insertion dimorphism differs from other types of polymorphism (e.g. Variable Number of Tandem Repeat [VNTR] or Restriction Fragment Length Polymorphism [RFLP]) because individuals share HS Alu family member insertions based upon identity by descent from a common ancestor as a result of a single event which occurred one time within the human population. The VNTR and RFLP polymorphisms may arise multiple times within a population and are identical by state only.

  15. TRStalker: an efficient heuristic for finding fuzzy tandem repeats.

    Science.gov (United States)

    Pellegrini, Marco; Renda, M Elena; Vecchio, Alessio

    2010-06-15

    Genomes in higher eukaryotic organisms contain a substantial amount of repeated sequences. Tandem Repeats (TRs) constitute a large class of repetitive sequences that are originated via phenomena such as replication slippage and are characterized by close spatial contiguity. They play an important role in several molecular regulatory mechanisms, and also in several diseases (e.g. in the group of trinucleotide repeat disorders). While for TRs with a low or medium level of divergence the current methods are rather effective, the problem of detecting TRs with higher divergence (fuzzy TRs) is still open. The detection of fuzzy TRs is propaedeutic to enriching our view of their role in regulatory mechanisms and diseases. Fuzzy TRs are also important as tools to shed light on the evolutionary history of the genome, where higher divergence correlates with more remote duplication events. We have developed an algorithm (christened TRStalker) with the aim of detecting efficiently TRs that are hard to detect because of their inherent fuzziness, due to high levels of base substitutions, insertions and deletions. To attain this goal, we developed heuristics to solve a Steiner version of the problem for which the fuzziness is measured with respect to a motif string not necessarily present in the input string. This problem is akin to the 'generalized median string' that is known to be an NP-hard problem. Experiments with both synthetic and biological sequences demonstrate that our method performs better than current state of the art for fuzzy TRs and that the fuzzy TRs of the type we detect are indeed present in important biological sequences. TRStalker will be integrated in the web-based TRs Discovery Service (TReaDS) at bioalgo.iit.cnr.it. Supplementary data are available at Bioinformatics online.

  16. IMHEX fuel cell repeat component manufacturing continuous improvement accomplishments

    Energy Technology Data Exchange (ETDEWEB)

    Jakaitis, L.A.; Petraglia, V.J.; Bryson, E.S. [M-C Power Corp., Burr Ridge, IL (United States)] [and others

    1996-12-31

    M-C Power is taking a power generation technology that has been proven in the laboratory and is making it a commercially competitive product. There are many areas in which this technology required scale up and refinement to reach the market entry goals for the IMHEX{reg_sign} molten carbonate fuel cell power plant. One of the primary areas that needed to be addressed was the manufacturing of the fuel cell stack. Up to this point, the fuel cell stack and associated components were virtually hand made for each system to be tested. M-C Power has now continuously manufactured the repeat components for three 250 kW stacks. M-C Power`s manufacturing strategy integrated both evolutionary and revolutionary improvements into its comprehensive commercialization effort. M-C Power`s objectives were to analyze and continuously improve stack component manufacturing and assembly techniques consistent with established specifications and commercial scale production requirements. Evolutionary improvements are those which naturally occur as the production rates are increased and experience is gained. Examples of evolutionary (learning curve) improvements included reducing scrap rates and decreasing raw material costs by buying in large quantities. Revolutionary improvements result in significant design and process changes to meet cost and performance requirements of the market entry system. Revolutionary changes often involve identifying new methods and developing designs to accommodate the new process. Based upon our accomplishments, M-C Power was able to reduce the cost of continuously manufactured fuel cell repeat components from the first to third 250 kW stack by 63%. This paper documents the continuous improvement accomplishments realized by M-C Power during IMHEX{reg_sign} fuel cell repeat component manufacturing.

  17. Use of passive repeaters for tunnel surface communications

    International Nuclear Information System (INIS)

    Capista, D.; McDowell, D.

    1996-04-01

    Many times there is a need to establish ratio communication between the surface and a beam enclosure. When one solicits communication companies for solutions, the answer is often to purchase expensive communication equipment such as repeaters or radiax type cable which can cost in the tens of thousands of dollars. This TM will describe an inexpensive solution to this problem and the results that can be expected. The cost of a passive repeater is $100--$200 depending on how elaborate one wants to be. A passive repeater system consists of two antennas connected together with a transmission line. When using VHF or UHF transceivers, one can use 5/8 wave mobile antennas, such as the Larson NMO406-CK for the 400--420 MHz range, with the antenna connected to a 19 inch square piece of aluminum to act as a ground plane. This type of antenna has reasonably good gain, seems to be adequate, and is inexpensive. Another antenna choice is to cut a dipole out of bus wire and solder this wire to a female N connector. Using a dipole seems to work OK in the tunnel and avoids the problem of having a wire sticking down for people to poke their eye with. The cable connecting the antennas should be of good quality so that the signal lost in the cable is minimal. The authors chose Belden 9913 coax. This cable has a characteristic impedance of 50 ohms and has 2.7 dB/100 ft. of attenuation at 400 MHz

  18. Dispersion Measure Variation of Repeating Fast Radio Burst Sources

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuan-Pei; Zhang, Bing, E-mail: yypspore@gmail.com, E-mail: zhang@physics.unlv.edu [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2017-09-20

    The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an apparent increase was recently seen with newly detected VLA bursts. It is expected that more repeating FRB sources may be detected in the future. In this work, we investigate a list of possible astrophysical processes that might cause DM variation of a particular FRB source. The processes include (1) cosmological scale effects such as Hubble expansion and large-scale structure fluctuations; (2) FRB local effects such as gas density fluctuation, expansion of a supernova remnant (SNR), a pulsar wind nebula, and an H ii region; and (3) the propagation effect due to plasma lensing. We find that the DM variations contributed by the large-scale structure are extremely small, and any observable DM variation is likely caused by the plasma local to the FRB source. In addition to mechanisms that decrease DM over time, we suggest that an FRB source in an expanding SNR around a nearly neutral ambient medium during the deceleration (Sedov–Taylor and snowplow) phases or in a growing H ii region can increase DM. Some effects (e.g., an FRB source moving in an H ii region or plasma lensing) can produce either positive or negative DM variations. Future observations of DM variations of FRB 121102 and other repeating FRB sources can provide important clues regarding the physical origin of these sources.

  19. Neck-cooling improves repeated sprint performance in the heat

    Directory of Open Access Journals (Sweden)

    Caroline eSunderland

    2015-11-01

    Full Text Available The present study evaluated the effect of neck-cooling during exercise on repeated sprint ability in a hot environment. Seven team-sport playing males completed two experimental trials involving repeated sprint exercise (5 x 6 s before and after two 45 min bouts of a football specific intermittent treadmill protocol in the heat (33.0  0.2 ºC; 53 ± 2% relative humidity. Participants wore a neck-cooling collar in one of the trials (CC. Mean power output and peak power output declined over time in both trials but were higher in CC (540 ± 99 v 507 ± 122W, d = 0.32; 719 ± 158 v 680 ± 182 W, d = 0.24 respectively. The improved power output was particularly pronounced (d = 0.51 – 0.88 after the 2nd 45 min bout but the CC had no effect on % fatigue. The collar lowered neck temperature and the thermal sensation of the neck (P 0.05. There were no trial differences but interaction effects were demonstrated for prolactin concentration and rating of perceived exertion (RPE. Prolactin concentration was initially higher in the collar cold trial and then was lower from 45 minutes onwards (interaction trial x time P=0.04. RPE was lower during the football intermittent treadmill protocol in the collar cold trial (interaction trial x time P = 0.01. Neck-cooling during exercise improves repeated sprint performance in a hot environment without altering physiological or neuroendocrinological responses. RPE is reduced and may partially explain the performance improvement.

  20. Carbohydrate mouth rinse does not improve repeated sprint performance

    Directory of Open Access Journals (Sweden)

    Leandro Ricardo Altimari

    2013-09-01

    Full Text Available The objective of this study was to evaluate the effect of a carbohydrate mouth rinse on the repeated sprint ability (RSA of young soccer players. Nine youth soccer players (15.0 ± 1.5 years; 60.7 ± 4.84 kg; 1.72 ± 0.05 m; 20.5 ± 1.25 kg/m2 were selected. The athletes were submitted to an RSA test consisting of six sprints of 40 m (going/return = 20 m + 20 m, separated by 20 s of passive recovery, under three experimental conditions: carbohydrate mouth rinse (CHO or placebo (PLA and control (CON. The mouth rinses containing CHO or PLA were administered 5 min and immediately before the beginning of the test in doses of 100 mL. The best sprint time (RSAbest, mean sprint time (RSAmean, and drop-off in sprint performance (fatigue index were determined for the different treatments. One-not identify significant differences (p> 0.05 in RSAbest (CHO way ANOVA for repeated measures did = 7.30 ± 0.31 s; PLA = 7.30 ± 0.30 s; CON = 7.26 ±0.16 s, RSA mean (CHO = 7.71 ± 0.30 s; PLA = 7.71 ± 0.25 s; CON = 7.66 ± 0.24s, or fatigue index (CHO = 5.58 ± 2.16%; PLA = 5.77 ± 3.04%; CON = 5.55 ±3.72%. The results suggest that a carbohydrate mouth rinse does not improve the repeated sprint performance of young soccer players.

  1. Dispersion Measure Variation of Repeating Fast Radio Burst Sources

    International Nuclear Information System (INIS)

    Yang, Yuan-Pei; Zhang, Bing

    2017-01-01

    The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an apparent increase was recently seen with newly detected VLA bursts. It is expected that more repeating FRB sources may be detected in the future. In this work, we investigate a list of possible astrophysical processes that might cause DM variation of a particular FRB source. The processes include (1) cosmological scale effects such as Hubble expansion and large-scale structure fluctuations; (2) FRB local effects such as gas density fluctuation, expansion of a supernova remnant (SNR), a pulsar wind nebula, and an H ii region; and (3) the propagation effect due to plasma lensing. We find that the DM variations contributed by the large-scale structure are extremely small, and any observable DM variation is likely caused by the plasma local to the FRB source. In addition to mechanisms that decrease DM over time, we suggest that an FRB source in an expanding SNR around a nearly neutral ambient medium during the deceleration (Sedov–Taylor and snowplow) phases or in a growing H ii region can increase DM. Some effects (e.g., an FRB source moving in an H ii region or plasma lensing) can produce either positive or negative DM variations. Future observations of DM variations of FRB 121102 and other repeating FRB sources can provide important clues regarding the physical origin of these sources.

  2. The rise in carboxyhemoglobin from repeated pulmonary diffusing capacity tests.

    Science.gov (United States)

    Zavorsky, Gerald S

    2013-03-01

    The purpose of this study determined the rise in carboxyhemoglobin percentage (COHb) from repeated pulmonary diffusing capacity tests using 5 or 10s single breath-hold maneuvers. Five male and four female non-smokers [baseline COHb=1.2 (SD 0.5%)] performed repeated pulmonary diffusing capacity testing on two separate days. The days were randomized to either repeated 10s (0.28% CO), or 5s (0.28% CO, 55ppm NO) breath-hold maneuvers. Twenty-two 5s breath-hold maneuvers, each separated by 4min rest, raised COHb to 11.1 (1.4)% and minimally raised the methemoglobin percentage (METHb) by 0.3 (0.2)% to a value of 0.8 (0.2)%. After the 22nd test, pulmonary diffusing capacity for carbon monoxide (DLCO) was reduced by about 4mL/min/mmHg, equating to a 0.44% increase in COHb per 5s breath-hold maneuver and a concomitant 0.35mL/min/mmHg decrease in DLCO. Pulmonary diffusing capacity for nitric oxide (DLNO) was not altered after 22 tests. On another day, the 10s single breath-hold maneuver increased COHb by 0.64% per test, and reduced DLCO by 0.44mL/min/mmHg per test. In conclusion, 5s breath-hold maneuvers do not appreciably raise METHb or DLNO, and DLCO is only significantly reduced when COHb is at least 6%. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Enhanced appetitive conditioning following repeated pretreatment with d-amphetamine.

    Science.gov (United States)

    Harmer, C J; Phillips, G D

    1998-07-01

    The behavioural response to psychomotor stimulants is augmented with repeated exposure to these drugs. Enhanced stimulated dopamine overflow within the nucleus accumbens and amygdala has been found to accompany this behavioural sensitization. In the present experiment, rats received 2 mg/kg d-amphetamine or 1 ml/kg physiological saline once per day for 5 days. Five days later, a behavioural assay confirmed that prior repeated d-amphetamine treatment markedly enhanced the locomotor activating effects of a d-amphetamine (0.5 mg/kg, i.p.) challenge. Training on a Pavlovian conditioning task began six days subsequently. In Stage 1, a stimulus (light or tone, S-) was presented negatively correlated with a sucrose reward. In Stage 2, presentation of the alternative counterbalanced stimulus (light or tone, S+) was paired with the availability of a 10% sucrose solution. There were no differences between the two groups in their response to the the S- stimulus. However, sensitized animals showed a selective enhancement in the acquisition of conditioned responding to S+, relative to vehicle-injected controls. No differences in behaviour were recorded during the prestimulus periods, nor during presentations of sucrose. Levels of activity within the operant chamber extraneous to alcove approach were also similar in both groups of animals. The conditioned instrumental efficacy of S+, relative to S- was assessed in Stage 3, in which stimulus availability was made contingent on a novel lever-pressing response. Both groups showed a similar preference for the S+ over the S- stimulus. Hence, rats sensitized by prior repeated d-amphetamine showed enhanced appetitive Pavlovian conditioning, without subsequent effect on conditioned reward efficacy. These data are discussed in light of possible changes in mesoamygdaloid dopamine functioning.

  4. Plasmid P1 replication: negative control by repeated DNA sequences.

    OpenAIRE

    Chattoraj, D; Cordes, K; Abeles, A

    1984-01-01

    The incompatibility locus, incA, of the unit-copy plasmid P1 is contained within a fragment that is essentially a set of nine 19-base-pair repeats. One or more copies of the fragment destabilizes the plasmid when present in trans. Here we show that extra copies of incA interfere with plasmid DNA replication and that a deletion of most of incA increases plasmid copy number. Thus, incA is not essential for replication but is required for its control. When cloned in a high-copy-number vector, pi...

  5. Wages and employment in a repeated game with revenue fluctuations

    DEFF Research Database (Denmark)

    Schultz, Christian

    1997-01-01

    Empirical investigations suggests that the real wage is surprisingly flat over the business cycle. This paper analyses a repeated game between a union and a firm which can contribute to explaining the flat wage. The parties cannot enter binding contracts, and revenue is fluctuating. The paper...... focuses on the best subgame-perfect equilibrium among those sharing the expected surplus in given fixed shares - e.g. equal shares. It is shown that (for moderate discount factors) this equilibrium has a more counter-cyclical wage, than what would be the case if the parties shared the surplus in each...

  6. Behavioral sensitization after repeated formaldehyde exposure in rats.

    Science.gov (United States)

    Sorg, B A; Hochstatter, T

    1999-01-01

    Multiple chemical sensitivity (MCS) is a phenomenon whereby individuals report increased sensitivity to chemicals in the environment, and attribute their sensitivities to prior exposure to the same or often structurally unrelated chemicals. A leading hypothesis suggests that MCS is akin to behavioral sensitization observed in rodents after repeated exposure to drugs of abuse or environmental stressors. Sensitization occurring within limbic circuitry of the central nervous system (CNS) may explain the multisymptom complaints in individuals with MCS. The present studies represent the continuing development of an animal model for MCS, the basis of which is the CNS sensitization hypothesis. Three behaviors were assessed in rats repeatedly exposed to formaldehyde (Form) inhalation. In the first series of experiments, rats were given high-dose Form exposure (11 parts per million [ppm]; 1 h/day x 7 days) or low-dose Form exposure (1 ppm; either 1 h/day x 7 days or 1 h/day x 5 days/week x 4 weeks). Within a few days after discontinuing daily Form, cocaine-induced locomotor activity was elevated after high-dose Form or 20 days of low-dose Form inhalation. Approximately 1 month later, cocaine-induced locomotor activity remained significantly elevated in the 20-day Form-exposed rats. The second experiment assessed whether prior exposure to Form (20 days, as above) would alter the ability to condition to an odor (orange oil) paired with footshock. The results suggested a tendency to increase the conditioned fear response to the odor but not the context of the footshock box, and a decreased tendency to extinguish the conditioned fear response to odor. The third experiment examined whether CNS sensitization to daily cocaine or stress would alter subsequent avoidance responding to odor (Form). Daily cocaine significantly elevated approach responses to Form, while daily stress pretreatment produced a trend in the opposite direction, producing greater avoidance of Form. Preliminary

  7. Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress.

    Directory of Open Access Journals (Sweden)

    Olivier Girard

    Full Text Available Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C and CON (25°C conditions.Eleven recreationally active males performed a 30-min warm-up followed by three sets of five 5-s sprints with 25-s recovery and 3-min between sets in each environment. Constant-velocity running for 1-min at 10 and 20 km.h-1 was also performed prior to and following sprinting.Mean skin (37.2±0.7 vs. 32.7±0.8°C; P<0.001 and core (38.9±0.2 vs. 38.8±0.3°C; P<0.05 temperatures, together with thermal comfort (P<0.001 were higher following repeated sprinting in HOT vs. CON. Step frequency and vertical stiffness were lower (-2.6±1.6% and -5.5±5.5%; both P<0.001 and contact time (+3.2±2.4%; P<0.01 higher in HOT for the mean of sets 1-3 compared to CON. Running distance per sprint decreased from set 1 to 3 (-7.0±6.4%; P<0.001, with a tendency for shorter distance covered in HOT vs. CON (-2.7±3.4%; P = 0.06. Mean vertical (-2.6±5.5%; P<0.01, horizontal (-9.1±4.4%; P<0.001 and resultant ground reaction forces (-3.0±2.8%; P<0.01 along with vertical stiffness (-12.9±2.3%; P<0.001 and leg stiffness (-8.4±2.7%; P<0.01 decreased from set 1 to 3, independently of conditions. Propulsive power decreased from set 1 to 3 (-16.9±2.4%; P<0.001, with lower propulsive power values in set 2 (-6.6%; P<0.05 in HOT vs. CON. No changes in constant-velocity running patterns occurred between conditions, or from pre-to-post repeated-sprint exercise.Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constant-velocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations.

  8. Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress

    Science.gov (United States)

    Brocherie, Franck; Morin, Jean-Benoit; Racinais, Sébastien; Millet, Grégoire P.; Périard, Julien D.

    2017-01-01

    Purpose Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions. Methods Eleven recreationally active males performed a 30-min warm-up followed by three sets of five 5-s sprints with 25-s recovery and 3-min between sets in each environment. Constant-velocity running for 1-min at 10 and 20 km.h-1 was also performed prior to and following sprinting. Results Mean skin (37.2±0.7 vs. 32.7±0.8°C; P<0.001) and core (38.9±0.2 vs. 38.8±0.3°C; P<0.05) temperatures, together with thermal comfort (P<0.001) were higher following repeated sprinting in HOT vs. CON. Step frequency and vertical stiffness were lower (-2.6±1.6% and -5.5±5.5%; both P<0.001) and contact time (+3.2±2.4%; P<0.01) higher in HOT for the mean of sets 1–3 compared to CON. Running distance per sprint decreased from set 1 to 3 (-7.0±6.4%; P<0.001), with a tendency for shorter distance covered in HOT vs. CON (-2.7±3.4%; P = 0.06). Mean vertical (-2.6±5.5%; P<0.01), horizontal (-9.1±4.4%; P<0.001) and resultant ground reaction forces (-3.0±2.8%; P<0.01) along with vertical stiffness (-12.9±2.3%; P<0.001) and leg stiffness (-8.4±2.7%; P<0.01) decreased from set 1 to 3, independently of conditions. Propulsive power decreased from set 1 to 3 (-16.9±2.4%; P<0.001), with lower propulsive power values in set 2 (-6.6%; P<0.05) in HOT vs. CON. No changes in constant-velocity running patterns occurred between conditions, or from pre-to-post repeated-sprint exercise. Conclusions Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constant-velocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations. PMID:28146582

  9. Acute caffeine effect on repeatedly measured P300

    OpenAIRE

    Pan, Jingbo; Takeshita, Tatsuya; Morimoto, Kanehisa

    2000-01-01

    The acute effect of a single-dose of caffeine on the P300 event-related brain potential (ERP) was assessed in a study using a repeatedly presented auditory oddball button-press task. A dose (5mg/kg body-weight) of either caffeine or placebo lactose, dissolved in a cup of decaffeinated coffee, was administered double-blindly to coffee drinkers who had abstained from coffee for 24hrs, with the presentation order of the sessions counterbalanced and separated by 2–4 weeks. The caffeine-treatment ...

  10. The effectiveness of eye-closure in repeated interviews

    OpenAIRE

    Vredeveldt, A.; Baddeley, A.D.; Hitch, G.J.

    2014-01-01

    Purpose Closing the eyes during recall can help witnesses remember more about a witnessed event. This study examined the effectiveness of eye-closure in a repeated recall paradigm with immediate free recall followed 1 week later by both free and cued recall. We examined whether eye-closure was more or less effective during the second free-recall attempt compared with the first, whether eye-closure during the first recall attempt had an impact on subsequent free- and cued-recall performance, a...

  11. Preservice science teachers' experiences with repeated, guided inquiry

    Science.gov (United States)

    Slack, Amy B.

    The purpose of this study was to examine preservice science teachers' experiences with repeated scientific inquiry (SI) activities. The National Science Education Standards (National Research Council, 1996) stress students should understand and possess the abilities to do SI. For students to meet these standards, science teachers must understand and be able to perform SI; however, previous research demonstrated that many teachers have naive understandings in this area. Teacher preparation programs provide an opportunity to facilitate the development of inquiry understandings and abilities. In this study, preservice science teachers had experiences with two inquiry activities that were repeated three times each. The research questions for this study were (a) How do preservice science teachers' describe their experiences with repeated, guided inquiry activities? (b) What are preservice science teachers' understandings and abilities of SI? This study was conducted at a large, urban university in the southeastern United States. The 5 participants had bachelor's degrees in science and were enrolled in a graduate science education methods course. The researcher was one of the course instructors but did not lead the activities. Case study methodology was used. Data was collected from a demographic survey, an open-ended questionnaire with follow-up interviews, the researcher's observations, participants' lab notes, personal interviews, and participants' journals. Data were coded and analyzed through chronological data matrices to identify patterns in participants' experiences. The five domains identified in this study were understandings of SI, abilities to conduct SI, personal feelings about the experience, science content knowledge, and classroom implications. Through analysis of themes identified within each domain, the four conclusions made about these preservice teachers' experiences with SI were that the experience increased their abilities to conduct inquiry

  12. Decomposition of Straw in Soil after Stepwise Repeated Additions

    DEFF Research Database (Denmark)

    Sørensen, Lasse Holst

    1979-01-01

    after the first repeated addition of labelled straw the soils were subjected to a number of “stress” treatments: addition of unlabelled glucose, air-drying, oven-drying, grinding and fumigation with vapour of chloroform, respectively. The CO2 that developed during the first 10 days after the treatments......, grinding the most. The effect of each treatment declined with an increasing number of successive additions of straw. The ratio between CO2 evolved after grinding and fumigation, respectively, revealed that grinding also exposed non-biomass material to accelerated decomposition. The effects of the stress...

  13. Modeling intraindividual variability with repeated measures data methods and applications

    CERN Document Server

    Hershberger, Scott L

    2013-01-01

    This book examines how individuals behave across time and to what degree that behavior changes, fluctuates, or remains stable.It features the most current methods on modeling repeated measures data as reported by a distinguished group of experts in the field. The goal is to make the latest techniques used to assess intraindividual variability accessible to a wide range of researchers. Each chapter is written in a ""user-friendly"" style such that even the ""novice"" data analyst can easily apply the techniques.Each chapter features:a minimum discussion of mathematical detail;an empirical examp

  14. Finite stage asymmetric repeated games: Both players' viewpoints

    KAUST Repository

    Li, Lichun

    2017-01-05

    In asymmetric zero-sum games, one player has superior information about the game over the other. It is known that the informed players (maximizer) face the tradeoff of exploiting its superior information at the cost of revealing its superior information, but the basic point of the uninformed player (minimizer)\\'s decision making remains unknown. This paper studies the finite stage asymmetric repeated games from both players\\' viewpoints, and derives that not only security strategies but also the opponents\\' corresponding best responses depends only on the informed player\\'s history action sequences. Moreover, efficient LP formulations to compute both player\\'s security strategies are provided.

  15. Semihierarchical quantum repeaters based on moderate lifetime quantum memories

    Science.gov (United States)

    Liu, Xiao; Zhou, Zong-Quan; Hua, Yi-Lin; Li, Chuan-Feng; Guo, Guang-Can

    2017-01-01

    The construction of large-scale quantum networks relies on the development of practical quantum repeaters. Many approaches have been proposed with the goal of outperforming the direct transmission of photons, but most of them are inefficient or difficult to implement with current technology. Here, we present a protocol that uses a semihierarchical structure to improve the entanglement distribution rate while reducing the requirement of memory time to a range of tens of milliseconds. This protocol can be implemented with a fixed distance of elementary links and fixed requirements on quantum memories, which are independent of the total distance. This configuration is especially suitable for scalable applications in large-scale quantum networks.

  16. Repeatability analysis on LPFGs written by a CO2 laser

    Science.gov (United States)

    Nespereira, Marta; Castro Alves, D.; Coelho, João. M. P.; Monteiro, Fernando; Abreu, Manuel; Rebordão, J. M.

    2014-08-01

    The physical mechanisms involved in the writing process of long period fiber gratings (LPFG) using mid-infrared radiation emitted by CO2 lasers limit the obtained characteristics, in particular the minimum period that can be achieved. In order to evaluate the performances of a new methodology developed by us, we analyzed its capability to produce gratings with different periods (from 600 μm down to 300 μm). We also present a repeatability study on the obtained LPFG characteristics (mainly the resonant wavelength and grating length) for several values of the repetition period.

  17. Firefighting and mental health: Experiences of repeated exposure to trauma.

    Science.gov (United States)

    Jahnke, Sara A; Poston, Walker S Carlos; Haddock, Christopher K; Murphy, Beth

    2016-02-15

    Firefighters must be ready to respond to a broad range of emergencies every duty day. In the course of many of these emergencies, firefighters witness events which have the potential to induce emotional trauma, such as badly injured people, deceased children, and individuals who are highly distraught. Previous research suggests that repeated exposure to these traumas (RET) may have negative impacts on the emotional and mental health of fire service personnel. Research on the mental health of firefighters has been limited to small surveys reporting the prevalence of specific mental health problems such as depression and post-traumatic stress disorder among firefighters. Despite the likelihood that RET leads to negative outcomes in firefighters, data is lacking on how exposure impacts fire service personnel. The current study examines the experiences of firefighters related to RET. Using formative research methods, we examined the beliefs and experiences of firefighters and administrators from across the United States regarding the impact of RET on firefighter health. Study findings highlight the cumulative psychological toll of repeated exposure to traumatic events including desensitization, flashbacks, and irritability. Results of the current study suggest that RET is a significant concern for emergency responders that warrants additional research and attention. It is likely that the long term consequences of RET are closely intertwined with other mental health outcomes and general well-being of this important occupational group.

  18. Recursion Of Binary Space As A Foundation Of Repeatable Programs

    Directory of Open Access Journals (Sweden)

    Jeremy Horne

    2006-10-01

    Full Text Available Every computation, including recursion, is based on natural philosophy. Our world may be expressed in terms of a binary logical space that contains functions that act simultaneously as objects and processes (operands and operators. This paper presents an outline of the results of research about that space and suggests routes for further inquiry. Binary logical space is generated sequentially from an origin in a standard coordinate system. At least one method exists to show that each of the resulting 16 functions repeats itself by repeatedly forward-feeding outputs of a function operating over two others as new operands of the original function until the original function appears as an output, thus behaving as an apparent homeostatic automaton. As any space of any dimension is composed of one or more of these functions, so the space is recursive, as well. Semantics gives meaning to recursive structures, computer programs and fundamental constituents of our universe being two examples. Such thoughts open inquiry into larger philosophical issues as free will and determinism.

  19. Analysis of repeated measurement data in the clinical trials

    Science.gov (United States)

    Singh, Vineeta; Rana, Rakesh Kumar; Singhal, Richa

    2013-01-01

    Statistics is an integral part of Clinical Trials. Elements of statistics span Clinical Trial design, data monitoring, analyses and reporting. A solid understanding of statistical concepts by clinicians improves the comprehension and the resulting quality of Clinical Trials. In biomedical research it has been seen that researcher frequently use t-test and ANOVA to compare means between the groups of interest irrespective of the nature of the data. In Clinical Trials we record the data on the patients more than two times. In such a situation using the standard ANOVA procedures is not appropriate as it does not consider dependencies between observations within subjects in the analysis. To deal with such types of study data Repeated Measure ANOVA should be used. In this article the application of One-way Repeated Measure ANOVA has been demonstrated by using the software SPSS (Statistical Package for Social Sciences) Version 15.0 on the data collected at four time points 0 day, 15th day, 30th day, and 45th day of multicentre clinical trial conducted on Pandu Roga (~Iron Deficiency Anemia) with an Ayurvedic formulation Dhatrilauha. PMID:23930038

  20. Repeated transsphenoidal surgery for resection of pituitary adenoma.

    Science.gov (United States)

    Wang, Shousen; Xiao, Deyong; Wang, Rumi; Wei, Liangfeng; Hong, Jingfang

    2015-03-01

    To investigate the surgical strategy of repeated microscopic transsphenoidal surgery (TSS) for treatment of pituitary adenoma, surgical techniques and treatment outcomes for 29 patients with pituitary adenoma were reviewed and analyzed. There were 17 patients who underwent TSS 18 times and 12 patients who underwent TSS 13 times. The interval between each TSS ranged from 3 months to 18 years, with a median time of 4 years. The tumor height was 15 to 45 mm on the last surgery. Among the 29 patients, 16 patients underwent total tumor resection, 11 patients underwent subtotal resection, and 2 patients underwent partial resection. Cerebrospinal fluid leak occurred in 10 patients. Among 24 patients who were followed up effectively, 1 patient developed abducens paralysis after surgery, 1 patient had chronic diabetes insipidus, and 1 patient received steroid-dependent alternative treatment. The repeated TSS may present satisfied outcomes in experienced hands. The upper edge of the posterior choanae should be identified to ensure the right orientation. The openings of the anterior wall of the sphenoid sinus and the sellar floor should be appropriately expanded to improve tumor exposure. The artificial materials should be identified and removed carefully. Intraoperative cerebrospinal fluid leakage should be managed well.

  1. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    Science.gov (United States)

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  2. The effects of repeated Ozurdex injections on ocular hypertension

    Directory of Open Access Journals (Sweden)

    Bahadorani S

    2018-04-01

    Full Text Available Sepehr Bahadorani,1 Chelsey Krambeer,2 Kendall Wannamaker,1 Wayne Tie,1 Michael Jansen,1 Jason Espitia,2 Jeong-Hyeon Sohn,1 Michael A Singer2 1Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA; 2Medical Center Ophthalmology Associates, San Antonio, TX, USA Purpose: The purpose of this study was to correlate the degree of ocular hypertension with the number of Ozurdex injections.Methods: Intraocular pressure (IOP fluctuations for a total of 183 injections were studied over a period of at least 12 months. The main indications for treatment were uveitis, diabetic macular edema, and retinal vein occlusion.Results: Results of the study demonstrate that repeated Ozurdex injections do not increase the frequency of IOP spikes beyond 30 mmHg. For lower IOPs, however, a positive correlation exists. Furthermore, patients with primary open angle glaucoma and uveitis had the highest IOP response to repeated injections. On average, patients with an IOP of ≥28.6 mmHg received pressure lowering medications, after which their IOP reached a stable level (16.7 mmHg without the need for additional interventions.Conclusion: The data support the conclusion that multiple Ozurdex injections does not increase the frequency of IOP spikes beyond 30 mmHg, but patients still must be closely monitored if they have a history of primary open angle glaucoma. Keywords: Ozurdex, dexamethasone, glaucoma, intraocular pressure, ocular hypertension

  3. Repeated imitation makes human vocalizations more word-like.

    Science.gov (United States)

    Edmiston, Pierce; Perlman, Marcus; Lupyan, Gary

    2018-03-14

    People have long pondered the evolution of language and the origin of words. Here, we investigate how conventional spoken words might emerge from imitations of environmental sounds. Does the repeated imitation of an environmental sound gradually give rise to more word-like forms? In what ways do these forms resemble the original sounds that motivated them (i.e. exhibit iconicity)? Participants played a version of the children's game 'Telephone'. The first generation of participants imitated recognizable environmental sounds (e.g. glass breaking, water splashing). Subsequent generations imitated the previous generation of imitations for a maximum of eight generations. The results showed that the imitations became more stable and word-like, and later imitations were easier to learn as category labels. At the same time, even after eight generations, both spoken imitations and their written transcriptions could be matched above chance to the category of environmental sound that motivated them. These results show how repeated imitation can create progressively more word-like forms while continuing to retain a resemblance to the original sound that motivated them, and speak to the possible role of human vocal imitation in explaining the origins of at least some spoken words. © 2018 The Author(s).

  4. Neuromuscular adjustments of the quadriceps muscle after repeated cycling sprints.

    Directory of Open Access Journals (Sweden)

    Olivier Girard

    Full Text Available PURPOSE: This study investigated the supraspinal processes of fatigue of the quadriceps muscle in response to repeated cycling sprints. METHODS: Twelve active individuals performed 10 × 6-s "all-out" sprints on a cycle ergometer (recovery = 30 s, followed 6 min later by 5 × 6-s sprints (recovery = 30 s. Transcranial magnetic and electrical femoral nerve stimulations during brief (5-s and sustained (30-s isometric contractions of the knee extensors were performed before and 3 min post-exercise. RESULTS: Maximal strength of the knee extensors decreased during brief and sustained contractions (~11% and 9%, respectively; P0.05. While cortical voluntary activation declined (P 40% reduced (P<0.001 following exercise. CONCLUSION: The capacity of the motor cortex to optimally drive the knee extensors following a repeated-sprint test was shown in sustained, but not brief, maximal isometric contractions. Additionally, peripheral factors were largely involved in the exercise-induced impairment in neuromuscular function, while corticospinal excitability was well-preserved.

  5. Results of repeated antireflux operations on hiatal hernias

    Directory of Open Access Journals (Sweden)

    Khubolov A.M.

    2016-06-01

    Full Text Available The research goal: to carry out the retrospective analysis of results of repeated antireflux interventions at the recurrent hernias of an esophageal opening of a diaphragm (HEOD. Material and methods. Results of surgical treatment of 38 patients with recurrence of HEOD in various terms after operation are studied. Results. At the most part of patients at repeated operations anatomic prerequisites to formation of recurrence of HEOD — migration of a fundoplication cuff, insolvency, an excessive tension of tissues when forming the gastric coupling, violation of technology of imposing of a cuff come to light. In this regard, proceeding from these references and the analysis of own research, it has been considered that plasticity of local tissues at recurrent HEOD, is insufficient for reliable elimination of a gastroesopha-geal reflux. Conclusion. The analysis of the results of antireflux surgical treatment of HEOD with a reflux-esophageal phenomenon has shown high efficiency of no tension plasticity, with use of a synthetic artificial limb. The fundoplication technique in antireflux surgery with no tension plasticity may be used as an operation of choice at recurrent hernias of an esophageal opening of a diaphragm.

  6. Validity and repeatability of goniometry in normal horses.

    Science.gov (United States)

    Adair, Henry S; Marcellin-Little, Denis J; Levine, David

    2016-07-19

    To assess validity and inter- and intra-tester reliability of equine goniometry and to establish values for carpal, metacarpophalangeal, tarsal, and metatarsophalangeal flexion and extension in horses. Seventeen healthy equine subjects of varied breeds were used. Three investigators blindly and independently measured in triplicate the extension and flexion of carpal, metacarpophalangeal, tarsal, and metatarsophalangeal joints of 17 horses after sedation. Radiographs of these joints in flexion and extension were acquired while under sedation. Goniometric and radiographic measurements were compared statistically and were correlated. A Bland-Altman plot was constructed. Inter- and intra-tester repeatability of goniometry were evaluated by calculating intraclass correlation coefficients (ICC). Mean flexion and extension of carpal, metacarpophalangeal, tarsal, and metatarsophalangeal joints were calculated. Goniometric and radiographic measurements did not differ statistically and were significantly correlated (correlation coefficients ranged from 0.59 - 0.89). The mean difference between goniometric and radiographic measurements was 0.4°. Triplicate measurements collected by the three raters did not differ significantly within raters (ICC ranging from 0.950 - 0.995) and between raters (ICC ranging from 0.942 - 0.989). Goniometry is a valid and repeatable tool for evaluation of the range of motion of carpal, metacarpophalangeal, tarsal, and metatarsophalangeal joints in standing, sedated healthy horses.

  7. The effects of repeated Ozurdex injections on ocular hypertension.

    Science.gov (United States)

    Bahadorani, Sepehr; Krambeer, Chelsey; Wannamaker, Kendall; Tie, Wayne; Jansen, Michael; Espitia, Jason; Sohn, Jeong-Hyeon; Singer, Michael A

    2018-01-01

    The purpose of this study was to correlate the degree of ocular hypertension with the number of Ozurdex injections. Intraocular pressure (IOP) fluctuations for a total of 183 injections were studied over a period of at least 12 months. The main indications for treatment were uveitis, diabetic macular edema, and retinal vein occlusion. Results of the study demonstrate that repeated Ozurdex injections do not increase the frequency of IOP spikes beyond 30 mmHg. For lower IOPs, however, a positive correlation exists. Furthermore, patients with primary open angle glaucoma and uveitis had the highest IOP response to repeated injections. On average, patients with an IOP of ≥28.6 mmHg received pressure lowering medications, after which their IOP reached a stable level (16.7 mmHg) without the need for additional interventions. The data support the conclusion that multiple Ozurdex injections does not increase the frequency of IOP spikes beyond 30 mmHg, but patients still must be closely monitored if they have a history of primary open angle glaucoma.

  8. The Student Volunteer Army: a 'repeat emergent' emergency response organisation.

    Science.gov (United States)

    Carlton, Sally; Mills, Colleen E

    2017-10-01

    This paper seeks to contribute to understanding of the factors associated with an effective emergent emergency response organisation and to provide new insights into this understudied area. It examines, through an analysis of a range of textual resources, the emergence and re-emergence of the Student Volunteer Army (SVA) during the devastating earthquakes in Canterbury, New Zealand, in 2010-11. This evaluation is conducted in relation to the four key features of an effective emergency response organisation: adaptability; direction; leadership; and communication. In addition, the paper aims to further understanding of 'emergency entrepreneurship' and thus of the values and strategies that underpin social entrepreneur organisations in times of normalcy. The paper concludes that the unique position of the SVA as a 'repeat emergent' emergency response organisation enabled it to innovate continually and to improve repeatedly its systems, relationships, and image, such that it exhibited features common to emergent and established emergency response organisations. © 2017 The Author(s). Disasters © Overseas Development Institute, 2017.

  9. Simple sequence repeat marker loci discovery using SSR primer.

    Science.gov (United States)

    Robinson, Andrew J; Love, Christopher G; Batley, Jacqueline; Barker, Gary; Edwards, David

    2004-06-12

    Simple sequence repeats (SSRs) have become important molecular markers for a broad range of applications, such as genome mapping and characterization, phenotype mapping, marker assisted selection of crop plants and a range of molecular ecology and diversity studies. With the increase in the availability of DNA sequence information, an automated process to identify and design PCR primers for amplification of SSR loci would be a useful tool in plant breeding programs. We report an application that integrates SPUTNIK, an SSR repeat finder, with Primer3, a PCR primer design program, into one pipeline tool, SSR Primer. On submission of multiple FASTA formatted sequences, the script screens each sequence for SSRs using SPUTNIK. The results are parsed to Primer3 for locus-specific primer design. The script makes use of a Web-based interface, enabling remote use. This program has been written in PERL and is freely available for non-commercial users by request from the authors. The Web-based version may be accessed at http://hornbill.cspp.latrobe.edu.au/

  10. The C9orf72 repeat expansion disrupts nucleocytoplasmic transport.

    Science.gov (United States)

    Zhang, Ke; Donnelly, Christopher J; Haeusler, Aaron R; Grima, Jonathan C; Machamer, James B; Steinwald, Peter; Daley, Elizabeth L; Miller, Sean J; Cunningham, Kathleen M; Vidensky, Svetlana; Gupta, Saksham; Thomas, Michael A; Hong, Ingie; Chiu, Shu-Ling; Huganir, Richard L; Ostrow, Lyle W; Matunis, Michael J; Wang, Jiou; Sattler, Rita; Lloyd, Thomas E; Rothstein, Jeffrey D

    2015-09-03

    The hexanucleotide repeat expansion (HRE) GGGGCC (G4C2) in C9orf72 is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recent studies support an HRE RNA gain-of-function mechanism of neurotoxicity, and we previously identified protein interactors for the G4C2 RNA including RanGAP1. A candidate-based genetic screen in Drosophila expressing 30 G4C2 repeats identified RanGAP (Drosophila orthologue of human RanGAP1), a key regulator of nucleocytoplasmic transport, as a potent suppressor of neurodegeneration. Enhancing nuclear import or suppressing nuclear export of proteins also suppresses neurodegeneration. RanGAP physically interacts with HRE RNA and is mislocalized in HRE-expressing flies, neurons from C9orf72 ALS patient-derived induced pluripotent stem cells (iPSC-derived neurons), and in C9orf72 ALS patient brain tissue. Nuclear import is impaired as a result of HRE expression in the fly model and in C9orf72 iPSC-derived neurons, and these deficits are rescued by small molecules and antisense oligonucleotides targeting the HRE G-quadruplexes. Nucleocytoplasmic transport defects may be a fundamental pathway for ALS and FTD that is amenable to pharmacotherapeutic intervention.

  11. Evidence for a Creative Dilemma Posed by Repeated Collaborations.

    Directory of Open Access Journals (Sweden)

    Hiroyasu Inoue

    Full Text Available We focused on how repeat collaborations in projects for inventions affect performance. Repeat collaborations have two contradictory aspects. A positive aspect is team development or experience, and a negative aspect is team degeneration or decline. Since both contradicting phenomena are observed, inventors have a dilemma as to whether they should keep collaborating in a team or not. The dilemma has not previously been quantitatively analyzed. We provide quantitative and extensive analyses of the dilemma in creative projects by using patent data from Japan and the United States. We confirm three predictions to quantitatively validate the existence of the dilemma. The first prediction is that the greater the patent a team achieves, the longer the team will work together. The second prediction is that the impact of consecutive patents decreases after a team makes a remarkable invention, which is measured by the impact of patents. The third prediction is that the expectation of impact with new teams is greater than that with the same teams successful in the past. We find these predictions are validated in patents published in Japan and the United States. On the basis of these three predictions, we can quantitatively validate the dilemma in creative projects. We also propose preventive strategies for degeneration. One is developing technological diversity, and another is developing inventor diversity in teams. We find the two strategies are both effective by validating with the data.

  12. Repeated Raking of Pine Plantations Alters Soil Arthropod Communities

    Directory of Open Access Journals (Sweden)

    Holly K. Ober

    2014-04-01

    Full Text Available Terrestrial arthropods in forests are engaged in vital ecosystem functions that ultimately help maintain soil productivity. Repeated disturbance can cause abrupt and irreversible changes in arthropod community composition and thereby alter trophic interactions among soil fauna. An increasingly popular means of generating income from pine plantations in the Southeastern U.S. is annual raking to collect pine litter. We raked litter once per year for three consecutive years in the pine plantations of three different species (loblolly, Pinus taeda; longleaf, P. palustris; and slash, P. elliottii. We sampled arthropods quarterly for three years in raked and un-raked pine stands to assess temporal shifts in abundance among dominant orders of arthropods. Effects varied greatly among orders of arthropods, among timber types, and among years. Distinct trends over time were apparent among orders that occupied both high trophic positions (predators and low trophic positions (fungivores, detritivores. Multivariate analyses demonstrated that raking caused stronger shifts in arthropod community composition in longleaf and loblolly than slash pine stands. Results highlight the role of pine litter in shaping terrestrial arthropod communities, and imply that repeated removal of pine straw during consecutive years is likely to have unintended consequences on arthropod communities that exacerbate over time.

  13. A case of repeated intracerebral hemorrhages secondary to ventriculoperitoneal shunt

    Directory of Open Access Journals (Sweden)

    Jinbing Zhao

    2015-03-01

    Full Text Available Ventriculoperitoneal shunt is a routinely performed treatment in neurosurgical department. Intracerebral hemorrhage, as a complication after shunt catheterization, is really rare but with high mortality. In this study, we reported a case of a 74-year-old man who suffered from repeated intracerebral hemorrhage after ventriculoperitoneal shunt. The first hemorrhage happened 63 h after the 1st surgery, and most hematomas were located in the ipsilateral occipital lobe and intraventricles, along the ventricular catheter. Fresh blood clot casts blocked the external ventricular draining catheter, which was inserted into the right front horn during the 3rd surgery, indicating new intraventricular bleeding happened. A large hematoma in ipsilateral frontal lobe was detected on the 3rd day after the removal of external ventricular draining catheter. Different hemorrhagic locations and time points were encountered on the same case. We discussed the possible causes of repeated hemorrhage for this case, and the pre-operative preparation including risk evaluation in future clinical work.

  14. Protection of Buried Pipe under Repeated Loading by Geocell Reinforcement

    Science.gov (United States)

    Khalaj, Omid; Joz Darabi, N.; Moghaddas Tafreshi, S. N.; Mašek, Bohuslav

    2017-12-01

    With increase in cities’ population and development of urbane life, passing buried pipelines near ground’s surface is inevitable in urban areas, roads, subways and highways. This paper presents the results of three-dimensional full scale model tests on high-density polyethylene (HDPE) pipe with diameter of 250 mm in geocell reinforced soil, subjected to repeated loading to simulate the vehicle loads. The effect of geocell’s pocket size (55*55 mm and 110*110 mm) and embedment depth of buried pipe (1.5 and 2 times pipe diameter) in improving the behaviour of buried pipes was investigated. The geocell’s height of 100 mm was used in all tests. The repeated load of 800 kPa was applied on circular loading plate with diameter of 250 mm. The results show that the pipe displacement, soil surface settlement and transferred pressure on the pipe’s crown has been influenced significantly upon the use of geocells. For example, the vertical diametric strain (VDS) and soil surface settlement (SSS), in a way that using a geocell with pocket size of 110*110 mm reduces by 27% and 43%, respectively, compared with the unreinforced one. Meanwhile, by increasing buried depth of pipe from 1.5D to 2D, the use of geocell of 110*110 mm delivers about 50% reduction in SSS and VDS, compared with the unreinforced soil.

  15. MSDB: A Comprehensive Database of Simple Sequence Repeats.

    Science.gov (United States)

    Avvaru, Akshay Kumar; Saxena, Saketh; Sowpati, Divya Tej; Mishra, Rakesh Kumar

    2017-06-01

    Microsatellites, also known as Simple Sequence Repeats (SSRs), are short tandem repeats of 1-6 nt motifs present in all genomes, particularly eukaryotes. Besides their usefulness as genome markers, SSRs have been shown to perform important regulatory functions, and variations in their length at coding regions are linked to several disorders in humans. Microsatellites show a taxon-specific enrichment in eukaryotic genomes, and some may be functional. MSDB (Microsatellite Database) is a collection of >650 million SSRs from 6,893 species including Bacteria, Archaea, Fungi, Plants, and Animals. This database is by far the most exhaustive resource to access and analyze SSR data of multiple species. In addition to exploring data in a customizable tabular format, users can view and compare the data of multiple species simultaneously using our interactive plotting system. MSDB is developed using the Django framework and MySQL. It is freely available at http://tdb.ccmb.res.in/msdb. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  16. Neonates' responses to repeated exposure to a still face.

    Science.gov (United States)

    Nagy, Emese; Pilling, Karen; Watt, Rachel; Pal, Attila; Orvos, Hajnalka

    2017-01-01

    The main aims of the study were to examine whether human neonates' responses to communication disturbance modelled by the still-face paradigm were stable and whether their responses were affected by their previous experience with the still-face paradigm. The still face procedure, as a laboratory model of interpersonal stress, was administered repeatedly, twice, to 84 neonates (0 to 4 day olds), with a delay of an average of 1.25 day. Frame-by-frame analysis of the frequency and duration of gaze, distressed face, crying, sleeping and sucking behaviours showed that the procedure was stressful to them both times, that is, the still face effect was stable after repeated administration and newborns consistently responded to such nonverbal violation of communication. They averted their gaze, showed distress and cried more during the still-face phase in both the first and the second administration. They also showed a carry-over effect in that they continued to avert their gaze and displayed increased distress and crying in the first reunion period, but their gaze behaviour changed with experience, in the second administration. While in the first administration the babies continued averting their gaze even after the stressful still-face phase was over, this carry-over effect disappeared in the second administration, and the babies significantly increased their gaze following the still-face phase. After excluding explanations of fatigue, habituation and random effects, a self-other regulatory model is discussed as a possible explanation for this pattern.

  17. Fixed or adapted conditioning intensity for repeated conditioned pain modulation.

    Science.gov (United States)

    Hoegh, M; Petersen, K K; Graven-Nielsen, T

    2017-12-29

    Aims Conditioned pain modulation (CPM) is used to assess descending pain modulation through a test stimulation (TS) and a conditioning stimulation (CS). Due to potential carry-over effects, sequential CPM paradigms might alter the intensity of the CS, which potentially can alter the CPM-effect. This study aimed to investigate the difference between a fixed and adaptive CS intensity on CPM-effect. Methods On the dominant leg of 20 healthy subjects the cuff pressure detection threshold (PDT) was recorded as TS and the pain tolerance threshold (PTT) was assessed on the non-dominant leg for estimating the CS. The difference in PDT before and during CS defined the CPM-effect. The CPM-effect was assessed four times using a CS with intensities of 70% of baseline PTT (fixed) or 70% of PTT measured throughout the session (adaptive). Pain intensity of the conditioning stimulus was assessed on a numeric rating scale (NRS). Data were analyzed with repeated-measures ANOVA. Results No difference was found comparing the four PDTs assessed before CSs for the fixed and the adaptive paradigms. The CS pressure intensity for the adaptive paradigm was increasing during the four repeated assessments (P CPM-effect was higher using the fixed condition compared with the adaptive condition (P CPM paradigms using a fixed conditioning stimulus produced an increased CPM-effect compared with adaptive and increasing conditioning intensities.

  18. PHYSIOLOGICAL RESPONSES AND MOOD STATES AFTER DAILY REPEATED PROLONGED EXERCISE

    Directory of Open Access Journals (Sweden)

    Ilkka Väänänen

    2004-10-01

    Full Text Available The purpose of this study was to describe the physiological responses to daily repeated acute but non-competitive prolonged exercise during a 4-day march and a 2-day cross-country ski event to the cardiorespiratory, autonomic nervous, musculoskeletal and endocrine systems. Mood states were also evaluated after these repeated exercises. The data of these short-term follow-up (reversal field trials was collected from healthy, 23 to 48 year old Finnish male soldiers in 1993 (n=6 and 1994 (n=15 during the "International Four-Day Long-Distance March" in Nijmegen, The Netherlands, and from ten healthy, 22 to 48 year old Finnish male participants in 1995 during a 2-day Finlandia Ski Race in Lahti, Finland. Acute cardiovascular responses were estimated by measuring the heart rate during exercise. The responses of the autonomic nervous system were estimated by measuring the heart rates during the orthostatic test. The musculoskeletal responses were estimated by measuring the perceived pains, flexibility, functional strength, use of elastic energy and oedemic changes of the lower extremities. Hormonal responses were estimated from the urinary excretion of catecholamines, and the concentrations of serum cortisol, testosterone, luteinizing (LH and follicle stimulating hormone (FSH. Mood states were assessed with the Profile of Mood States (POMS questionnaire. Daily walking time was 7-10 hours while the skiing time was 3 hours. Average heart rate during walking was 59% and skiing 87% of maximum heart rate. Morning heart rate in the supine position increased progressively through the marching period but not through the skiing experiment. After the first day, perceived pain increased significantly and remained at a similarly increased level until the end of the exercise period. Leg measurements showed no signs of oedema, decreases in flexibility, or functional strength. Catecholamine excretion rates during marches indicated cumulatively increased

  19. USGS Southwest Repeat Photography Collection: Kanab Creek, southern Utah and northern Arizona, 1872-2010

    Data.gov (United States)

    Department of the Interior — The USGS Southwest Repeat Photography Collection (‘Collection’), formerly named the Desert Laboratory Repeat Photography Collection, is now housed by the...

  20. Prognostic usefulness of repeated echocardiographic evaluation after acute myocardial infarction. TRACE Study Group. TRAndolapril Cardiac Evaluation

    DEFF Research Database (Denmark)

    Korup, E; Køber, L; Torp-Pedersen, C

    1999-01-01

    The prognostic value of repeated echocardiographic measurement of left ventricular function after acute myocardial infarction was evaluated. We found that repeated measurements of wall motion index in survivors of acute myocardial infarction, with no reinfarction, provide important prognostic...

  1. Studies on serum macro and micro minerals status in repeat breeder ...

    African Journals Online (AJOL)

    user01

    2014-03-05

    Mar 5, 2014 ... as well as 11.5% to gross domestic product. Repeat breeding is one of ... signs with no clinical detectable reproductive disorders. *Corresponding ... repeat breeding includes abnormal recommencement of postpartum ovarian ...

  2. Evaluation of New Methodology for Health Hazard Assessment of Repeated Shock in Military Tactical Ground Vehicles

    National Research Council Canada - National Science Library

    Alem, Nabih; Hiltz, Ernest; Breaux-Sims, Arlene; Bumgardner, Bradley

    2004-01-01

    .... The research culminated with the development of a new HHA method for repeated jolt that is tailored for TGVs but is valid for most vehicles where the seated occupant is exposed to repeated (multiple) low-level shocks (jolt...

  3. Translation of dipeptide repeat proteins from the C9ORF72 expanded repeat is associated with cellular stress.

    Science.gov (United States)

    Sonobe, Yoshifumi; Ghadge, Ghanashyam; Masaki, Katsuhisa; Sendoel, Ataman; Fuchs, Elaine; Roos, Raymond P

    2018-08-01

    Expansion of a hexanucleotide repeat (HRE), GGGGCC, in the C9ORF72 gene is recognized as the most common cause of familial amyotrophic lateral sclerosis (FALS), frontotemporal dementia (FTD) and ALS-FTD, as well as 5-10% of sporadic ALS. Despite the location of the HRE in the non-coding region (with respect to the main C9ORF72 gene product), dipeptide repeat proteins (DPRs) that are thought to be toxic are translated from the HRE in all three reading frames from both the sense and antisense transcript. Here, we identified a CUG that has a good Kozak consensus sequence as the translation initiation codon. Mutation of this CTG significantly suppressed polyglycine-alanine (GA) translation. GA was translated when the G 4 C 2 construct was placed as the second cistron in a bicistronic construct. CRISPR/Cas9-induced knockout of a non-canonical translation initiation factor, eIF2A, impaired GA translation. Transfection of G 4 C 2 constructs induced an integrated stress response (ISR), while triggering the ISR led to a continuation of translation of GA with a decline in conventional cap-dependent translation. These in vitro observations were confirmed in chick embryo neural cells. The findings suggest that DPRs translated from an HRE in C9ORF72 aggregate and lead to an ISR that then leads to continuing DPR production and aggregation, thereby creating a continuing pathogenic cycle. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. 40 CFR 1065.305 - Verifications for accuracy, repeatability, and noise.

    Science.gov (United States)

    2010-07-01

    ..., repeatability, and noise. 1065.305 Section 1065.305 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Verifications for accuracy, repeatability, and noise. (a) This section describes how to determine the accuracy, repeatability, and noise of an instrument. Table 1 of § 1065.205 specifies recommended values for individual...

  5. Analysis of genetic polymorphism of nine short tandem repeat loci in ...

    African Journals Online (AJOL)

    Yomi

    2012-03-15

    Mar 15, 2012 ... Key words: short tandem repeat, repeat motif, genetic polymorphism, Han population, forensic genetics. INTRODUCTION. Short tandem repeat (STR) is widely .... Data analysis. The exact test of Hardy-Weinberg equilibrium was conducted with. Arlequin version 3.5 software (Computational and Molecular.

  6. 47 CFR 80.469 - Maritime mobile repeater stations in Alaska.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Maritime mobile repeater stations in Alaska. 80... RADIO SERVICES STATIONS IN THE MARITIME SERVICES Public Coast Stations Use of Telephony § 80.469 Maritime mobile repeater stations in Alaska. (a) Maritime mobile repeater stations are authorized to extend...

  7. Repeatability of cervical joint flexion and extension within and between days

    DEFF Research Database (Denmark)

    Wang, Xu; Lindstroem, René; Plocharski, Maciej

    2018-01-01

    OBJECTIVE: The purpose of this study was to investigate within- and between-day repeatability of free and unrestricted healthy cervical flexion and extension motion when assessing dynamic cervical spine motion. METHODS: Fluoroscopy videos of 2 repeated cervical flexion and 2 repeated extension...

  8. [Analysis of binary classification repeated measurement data with GEE and GLMMs using SPSS software].

    Science.gov (United States)

    An, Shengli; Zhang, Yanhong; Chen, Zheng

    2012-12-01

    To analyze binary classification repeated measurement data with generalized estimating equations (GEE) and generalized linear mixed models (GLMMs) using SPSS19.0. GEE and GLMMs models were tested using binary classification repeated measurement data sample using SPSS19.0. Compared with SAS, SPSS19.0 allowed convenient analysis of categorical repeated measurement data using GEE and GLMMs.

  9. Exposing Students to Repeat Photography: Increasing Cultural Understanding on a Short-Term Study Abroad

    Science.gov (United States)

    Lemmons, Kelly K.; Brannstrom, Christian; Hurd, Danielle

    2014-01-01

    Traditionally, repeat photography has been used to analyze land cover change. This paper describes how repeat photography may be used as a tool to enhance the short-term study abroad experience by facilitating cultural interaction and understanding. We present evidence from two cases and suggest a five-step repeat photography method for educators…

  10. The Role of the Repeat in the Bear Feast in Traditional Khanty Culture

    Directory of Open Access Journals (Sweden)

    Anna A. Grinevich (Zorkoltseva

    2012-09-01

    Full Text Available This paper is devoted to a role of repeat in Khanty folklore. Songs of a bear feast have served as the source material for the research. The author traces the role of a repeat at different text levels: structure, lexical level, and plot. The repeat is proposed as a fundamental method of traditional Khanty arts.

  11. An optimal algorithm for computing all subtree repeats in trees.

    Science.gov (United States)

    Flouri, T; Kobert, K; Pissis, S P; Stamatakis, A

    2014-05-28

    Given a labelled tree T, our goal is to group repeating subtrees of T into equivalence classes with respect to their topologies and the node labels. We present an explicit, simple and time-optimal algorithm for solving this problem for unrooted unordered labelled trees and show that the running time of our method is linear with respect to the size of T. By unordered, we mean that the order of the adjacent nodes (children/neighbours) of any node of T is irrelevant. An unrooted tree T does not have a node that is designated as root and can also be referred to as an undirected tree. We show how the presented algorithm can easily be modified to operate on trees that do not satisfy some or any of the aforementioned assumptions on the tree structure; for instance, how it can be applied to rooted, ordered or unlabelled trees.

  12. Measurement System Analyses - Gauge Repeatability and Reproducibility Methods

    Science.gov (United States)

    Cepova, Lenka; Kovacikova, Andrea; Cep, Robert; Klaput, Pavel; Mizera, Ondrej

    2018-02-01

    The submitted article focuses on a detailed explanation of the average and range method (Automotive Industry Action Group, Measurement System Analysis approach) and of the honest Gauge Repeatability and Reproducibility method (Evaluating the Measurement Process approach). The measured data (thickness of plastic parts) were evaluated by both methods and their results were compared on the basis of numerical evaluation. Both methods were additionally compared and their advantages and disadvantages were discussed. One difference between both methods is the calculation of variation components. The AIAG method calculates the variation components based on standard deviation (then a sum of variation components does not give 100 %) and the honest GRR study calculates the variation components based on variance, where the sum of all variation components (part to part variation, EV & AV) gives the total variation of 100 %. Acceptance of both methods among the professional society, future use, and acceptance by manufacturing industry were also discussed. Nowadays, the AIAG is the leading method in the industry.

  13. Repeated blood flow restriction induces muscle fiber hypertrophy.

    Science.gov (United States)

    Sudo, Mizuki; Ando, Soichi; Kano, Yutaka

    2017-02-01

    We recently developed an animal model to investigate the effects of eccentric contraction (ECC) and blood flow restriction (BFR) on muscle tissue at the cellular level. This study clarified the effects of repeated BFR, ECC, and BFR combined with ECC (BFR+ECC) on muscle fiber hypertrophy. Male Wistar rats were assigned to 3 groups: BFR, ECC, and BFR+ECC. The contralateral leg in the BFR group served as a control (CONT). Muscle fiber cross-sectional area (CSA) of the tibialis anterior was determined after the respective treatments for 6 weeks. CSA was greater in the BFR+ECC group than in the CONT (P muscle fiber hypertrophy at the cellular level. Muscle Nerve 55: 274-276, 2017. © 2016 Wiley Periodicals, Inc.

  14. Directional Cell Migration in Response to Repeated Substratum Stretching

    Science.gov (United States)

    Okimura, Chika; Iwadate, Yoshiaki

    2017-10-01

    Crawling migration plays an essential role in a variety of biological phenomena, including development, wound healing, and immune system function. Migration properties such as anterior-posterior polarity, directionality, and velocity are regulated not only by the reception of a chemoattractant but also by sensing mechanical inputs from the external environment. In this review, we describe the mechanical response of migrating cells, particularly under repeated stretching of the elastic substratum, highlighting the fact that there appear to be two independent mechanosensing systems that generate the polarity needed for migration. Cells that have no stress fibers, such as Dictyostelium cells and neutrophil-like differentiated HL-60 cells, migrate perpendicular to the stretching direction via myosin II localization. Cells that do possess stress fibers, however, such as fish keratocytes, migrate parallel to the stretching via a stress-fiber-dependent process.

  15. Reconditioning perovskite films in vapor environments through repeated cation doping

    Science.gov (United States)

    Boonthum, Chirapa; Pinsuwan, Kusuma; Ponchai, Jitprabhat; Srikhirin, Toemsak; Kanjanaboos, Pongsakorn

    2018-06-01

    Perovskites have attracted considerable attention for application as high-efficiency photovoltaic devices owing to their low-cost and low-temperature fabrication. A good surface and high crystallinity are necessary for high-performance devices. We examine the negative effects of chemical ambiences on the perovskite crystal formation and morphology. The repeated cation doping (RCD) technique was developed to remedy these issues by gradually dropping methylammonium ions on top of about-to-form perovskite surfaces to cause recrystallization. RCD promotes pinhole-free, compact, and polygonal-like surfaces under various vapor conditions. Furthermore, it enhances the electronic properties and crystallization. The benefits of RCD extend beyond perovskites under vapor ambiences, as it can improve regular and wasted perovskites.

  16. Effects of repeated skin exposure to low nickel concentrations

    DEFF Research Database (Denmark)

    Nielsen, N H; Menné, T; Kristiansen, J

    1999-01-01

    and nickel allergy, either on normal or on SLS-treated forearm skin. The present study strongly suggests that the changes observed were specific to nickel exposure. Standardized methods to assess trace to moderate nickel exposure on the hands, and the associated effects in nickel-sensitized subjects......We studied the effects of repeated daily exposure to low nickel concentrations on the hands of patients with hand eczema and nickel allergy. The concentrations used were chosen to represent the range of trace to moderate occupational nickel exposure. The study was double-blinded and placebo...... controlled. Patients immersed a finger for 10 min daily into a 10-p.p.m. nickel concentration in water for the first week, and during the second week into a 100-p.p.m. nickel concentration. This regimen significantly increased (P = 0.05) local vesicle formation and blood flow (P = 0.03) as compared...

  17. Repeated and Widespread Evolution of Bioluminescence in Marine Fishes.

    Directory of Open Access Journals (Sweden)

    Matthew P Davis

    Full Text Available Bioluminescence is primarily a marine phenomenon with 80% of metazoan bioluminescent genera occurring in the world's oceans. Here we show that bioluminescence has evolved repeatedly and is phylogenetically widespread across ray-finned fishes. We recover 27 independent evolutionary events of bioluminescence, all among marine fish lineages. This finding indicates that bioluminescence has evolved many more times than previously hypothesized across fishes and the tree of life. Our exploration of the macroevolutionary patterns of bioluminescent lineages indicates that the present day diversity of some inshore and deep-sea bioluminescent fish lineages that use bioluminescence for communication, feeding, and reproduction exhibit exceptional species richness given clade age. We show that exceptional species richness occurs particularly in deep-sea fishes with intrinsic bioluminescent systems and both shallow water and deep-sea lineages with luminescent systems used for communication.

  18. Repeated application of organic waste affects soil organic matter composition

    DEFF Research Database (Denmark)

    Peltre, Clément; Gregorich, Edward G.; Bruun, Sander

    2017-01-01

    Land application of organic waste is an important alternative to landfilling and incineration because it helps restore soil fertility and has environmental and agronomic benefits. These benefits may be related to the biochemical composition of the waste, which can result in the accumulation...... of different types of carbon compounds in soil. The objective of this study was to identify and characterise changes in soil organic matter (SOM) composition after repeated applications of organic waste. Soil from the CRUCIAL field experiment in Denmark was sampled after 12 years of annual application...... that there was accumulation in soil of different C compounds for the different types of applied organic waste, which appeared to be related to the degree to which microbial activity was stimulated and the type of microbial communities applied with the wastes or associated with the decomposition of applied wastes...

  19. The need for repeat angiography in subarachnoid haemorrhage

    International Nuclear Information System (INIS)

    Urbach, H.; Solymosi, L.; Zentner, J.

    1998-01-01

    This study was designed to assess the necessity for a second angiogram study in patients in whom initial angiography after primary subarachnoid haemorrhage (SAH) was negative. During a 12-year period, 122 of 694 patients (17.5 %) had negative initial angiograms. CT, available for 98 patients, showed a preponderance of subarachnoid blood in the perimesencephalic cisterns in 50 of 73 patients (68.5 %) in whom blood was visible on CT. Angiography, repeated in 67 patients, revealed an aneurysm in 4 (6 %): 2 had an aneurysm of the anterior communicating artery, 1 of the posterior inferior cerebellar artery, and 1 of the P2 segment of the posterior cerebral artery. CT showed subarachnoid blood in the interpeduncular and ambient cisterns in this last case, and a preponderance of subarachnoid blood outside the perimesencephalic cisterns in the remaining 3 patients. (orig.)

  20. The need for repeat angiography in subarachnoid haemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Urbach, H; Solymosi, L [Department of Neuroradiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn (Germany); Zentner, J [Department of Neurosurgery, University of Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn (Germany)

    1998-01-01

    This study was designed to assess the necessity for a second angiogram study in patients in whom initial angiography after primary subarachnoid haemorrhage (SAH) was negative. During a 12-year period, 122 of 694 patients (17.5 %) had negative initial angiograms. CT, available for 98 patients, showed a preponderance of subarachnoid blood in the perimesencephalic cisterns in 50 of 73 patients (68.5 %) in whom blood was visible on CT. Angiography, repeated in 67 patients, revealed an aneurysm in 4 (6 %): 2 had an aneurysm of the anterior communicating artery, 1 of the posterior inferior cerebellar artery, and 1 of the P2 segment of the posterior cerebral artery. CT showed subarachnoid blood in the interpeduncular and ambient cisterns in this last case, and a preponderance of subarachnoid blood outside the perimesencephalic cisterns in the remaining 3 patients. (orig.) With 2 figs., 1 tab., 32 refs.

  1. Of repeat stations and tectonic regionalization of Republic of Macedonia

    International Nuclear Information System (INIS)

    Delipetrev, Marjan; Doneva, Blagitsa; Delipetrov, Todor; Rasson, L. Jean

    2010-01-01

    Geomagnetic field is vector sum of causes deep in the Earth's interior and their influence can be felt in the whole Earth. There are sources of magnetic fields which are characterized for larger regions and local anomalous geomagnetic fields. When selecting the location of base station, regions where local geomagnetic anomalies are present, should be avoided, with aim to receive measured results which gives the geomagnetic field characteristic for that region. The territory of the Republic of Macedonia has complex relief, and also has complex geological structure and these features have high influence on the regional geomagnetic field. Bearing in mind the complex relief and geological structure, strict procedure of geomagnetic field observations were conducted for every selected location for repeat station. Maps from the measurements in 2004 are also presented in this paper. (Author)

  2. Repeated thinking promotes cooperation in spatial prisoner's dilemma game

    International Nuclear Information System (INIS)

    Zhang Jun; Cai Kaiquan; Du Wenbo; Cao Xianbin

    2012-01-01

    Inspired by the realistic process of taking decisions in social life, we have proposed a repeated thinking mechanism in the evolutionary spatial prisoner's dilemma game where players are denoted by the vertices and play games with their direct neighbors. Under our mechanism, a player i will randomly select a neighbor j and then deliberate for M times before strategy updating. It will remain unchanged if not all M considerations suggest it to learn the strategy of j. We mainly focus on the evolution of cooperation in the systems. Interestingly, we find that the cooperation level f C is remarkably promoted and f C has a monotonic dependence on the caution parameter M, indicating that being cautious facilitates the emergence and persistence of cooperation. We give a simple but clear explanation for this cooperation promotion via detecting the cooperator-defector transition process. Moreover, the robustness of this mechanism is also examined on different noise levels and game models. (paper)

  3. Effects of repeated regrouping on horse behaviour and injuries

    DEFF Research Database (Denmark)

    Christensen, Janne Winther; Søndergaard, Eva; Thodberg, Karen

    2011-01-01

    about how repeated regrouping affect horse behaviour and welfare, and it is unknown whether horses may adapt to regrouping. In this study, we aimed to investigate the effects of an unstable group structure, caused by weekly regroupings, on behaviour and frequency of injuries in young horses. Forty...... after each regrouping (2 × 20 min/group/day). Injuries were scored by the end of the experimental period. The level of aggression shown by horses in Unstable groups immediately after regrouping was not affected by week (F5,35 = 0.42, P = 0.83), indicating that horses neither habituated, nor sensitized...... injuries were registered and there was no treatment effect (U = 184; P = 0.11). We conclude that the behaviour of young horses is affected by group management, and that horses appear not to adapt to weekly regroupings....

  4. On the generalization of attitude accessibility after repeated attitude expression

    Science.gov (United States)

    Spruyt, Adriaan; Fazio, Russell H.; Hermans, Dirk

    2016-01-01

    Abstract The more accessible an attitude is, the stronger is its influence on information processing and behavior. Accessibility can be increased through attitude rehearsal, but it remains unknown whether attitude rehearsal also affects the accessibility of related attitudes. To investigate this hypothesis, participants in an experimental condition repeatedly expressed their attitudes towards exemplars of several semantic categories during an evaluative categorization task. Participants in a control condition performed a non‐evaluative task with the same exemplars and evaluated unrelated attitude objects. After a 30‐minute interval, participants in the experimental condition were faster than controls to evaluate not only the original exemplars but also novel exemplars of the same categories. This finding suggests that the effect of attitude rehearsal on accessibility generalizes to attitudes towards untrained but semantically related attitude objects. © 2016 The Authors. European Journal of Social Psychology published by John Wiley & Sons, Ltd. PMID:28701803

  5. Braking System Modeling and Brake Temperature Response to Repeated Cycle

    Directory of Open Access Journals (Sweden)

    Zaini Dalimus

    2014-12-01

    Full Text Available Braking safety is crucial while driving the passenger or commercial vehicles. Large amount of kinetic energy is absorbed by four brakes fitted in the vehicle. If the braking system fails to work, road accident could happen and may result in death. This research aims to model braking system together with vehicle in Matlab/Simulink software and measure actual brake temperature. First, brake characteristic and vehicle dynamic model were generated to estimate friction force and dissipated heat. Next, Arduino based prototype brake temperature monitoring was developed and tested on the road. From the experiment, it was found that brake temperature tends to increase steadily in long repeated deceleration and acceleration cycle.

  6. Impact of repeated insecticide application on soil microbial activity

    International Nuclear Information System (INIS)

    Xu Bujin; Zhang Yongxi; Chen Meici; Zhu Nanwen; Ming Hong

    2001-01-01

    The effects of repeated insecticide application on soil microbial activity were studied both in a cotton field and in the laboratory. The results of experiment show that there are some effects on soil microbial activities, such as the population of soil microorganisms, soil respiration, dehydrogenase activity and nitrogen fixation. The degree of effects depends on the chemical dosage. Within the range of 0.5-10.0 μg/g air-dry-soil, the higher the concentration, the stronger effect. In this experiment, the effect disappeared within 4, 8 or 16 days after treatment, depending on the dose applied. In field conditions, the situation is more complex and the data of field experiment show greater fluctuation. (author)

  7. Repeated batch and continuous degradation of chlorpyrifos by Pseudomonas putida.

    Science.gov (United States)

    Pradeep, Vijayalakshmi; Subbaiah, Usha Malavalli

    2015-01-01

    The present study was undertaken with the objective of studying repeated batch and continuous degradation of chlorpyrifos (O,O-diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate) using Ca-alginate immobilized cells of Pseudomonas putida isolated from an agricultural soil, and to study the genes and enzymes involved in degradation. The study was carried out to reduce the toxicity of chlorpyrifos by degrading it to less toxic metabolites. Long-term stability of pesticide degradation was studied during repeated batch degradation of chlorpyrifos, which was carried out over a period of 50 days. Immobilized cells were able to show 65% degradation of chlorpyrifos at the end of the 50th cycle with a cell leakage of 112 × 10(3) cfu mL(-1). During continuous treatment, 100% degradation was observed at 100 mL h(-1) flow rate with 2% chlorpyrifos, and with 10% concentration of chlorpyrifos 98% and 80% degradation was recorded at 20 mL h(-1) and 100 mL h(-1) flow rate respectively. The products of degradation detected by liquid chromatography-mass spectrometry analysis were 3,5,6-trichloro-2-pyridinol and chlorpyrifos oxon. Plasmid curing experiments with ethidium bromide indicated that genes responsible for the degradation of chlorpyrifos are present on the chromosome and not on the plasmid. The results of Polymerase chain reaction indicate that a ~890-bp product expected for mpd gene was present in Ps. putida. Enzymatic degradation studies indicated that the enzymes involved in the degradation of chlorpyrifos are membrane-bound. The study indicates that immobilized cells of Ps. putida have the potential to be used in bioremediation of water contaminated with chlorpyrifos.

  8. Characterisation of the Repeat Breeding Syndrome in Swedish Dairy Cattle

    Directory of Open Access Journals (Sweden)

    Emanuelson U

    2002-06-01

    Full Text Available Repeat breeding (RB, defined as cows failure to conceive from 3 or more regularly spaced services in the absence of detectable abnormalities, is a costly problem for the dairy producer. To elucidate the occurrence of RB in Swedish dairy herds and to identify risk factors of the syndrome totally 57,616 dairy cows in 1,541 herds were investigated based on data from the official Swedish production-, AI- and disease- recording schemes. The characteristics of the RB syndrome were studied on both herd and individual cow level. The effects of risk factors on the herd frequency of RB were studied by logistic regression. A generalised linear mixed model with logit link, and accounting for herd-level variation by including a random effect of herd, was used to study the individual animal risk for RB. The total percentage of RB animals was 10.1% and the median proportion of RB animals in the herds studied was 7.5%. The proportion of RB cows in herds increased with decreased herd sizes with decreased average days from calving to first AI, with increased herd incidence of clinical mastitis, with decreased reproductive disorders, and increased other diseases treated by a veterinarian. On animal level, the risk factors were milk yield, lactation number, difficult calving or dystocia, season at first service, days in milk at first service and veterinary treatment for reproductive disorders before the first service. Cows being an RB animal in the previous lactation had a higher risk of becoming an RB animal also in the present lactation. In conclusion our results show that the repeat breeding syndrome is a multifactorial problem involving a number of extrinsic factors as well as intrinsic factors coupled to the individual animal.

  9. Hybrid fibre-reinforced concrete under repeated loading

    International Nuclear Information System (INIS)

    Komlos, K.; Babal, B.; Nuernbergerova, T.

    1995-01-01

    Fibre-reinforced concrete containing several volume fractions in different ratios of two types of fibre - polypropylene and steel - were tested under repeated loading. The mechanical properties of specimens - cubes 150mm x 150mm x 150mm (for compressive strength), prisms 100mm x 100mm x 400mm (for flexural strength) and short cylinders 150mm long and 60mm in diameter (for impact strength) - have been experimentally investigated before and after cyclic loading after a curing time of 28 days.Mix proportions were designed according to DIN 1045 with maximum aggregate size 8mm and grading curve B8. Portland cement PC 40 in the amount of 450kgm -3 was applied and the water-to-cement ratio was 0.55. The workability of mixes was measured by the Vebe method and regulated by the plasticizing admixture Ligoplast Na. The maximum hybrid fibre volume fraction (polypropylene+steel) was 1.0%. The dynamic forces generated in a Schenck testing machine with a frequency of 16Hz had a sinusoidal waveform varying between 0.7 and 0.1 of the static mechanical characteristics. The number of cycles in all tests was 10 5 . The residual MOR in the static four-point bending test and working force-deflection diagram were also obtained. The impact properties after repeated loading in compression were tested by means of the falling-weight test. Relationships between the composition of fibre composites with different amounts of polypropylene (0.2, 0.3 and 0.5vol.%) and steel fibre content (0.5, 0.7 and 0.8vol.%) were obtained and the technological properties of the mixes as well. (orig.)

  10. The choroid plexus response to a repeated peripheral inflammatory stimulus

    Directory of Open Access Journals (Sweden)

    Palha Joana A

    2009-11-01

    Full Text Available Abstract Background Chronic systemic inflammation triggers alterations in the central nervous system that may relate to the underlying inflammatory component reported in neurodegenerative disorders such as multiple sclerosis and Alzheimer's disease. However, it is far from being understood whether and how peripheral inflammation contributes to induce brain inflammatory response in such illnesses. As part of the barriers that separate the blood from the brain, the choroid plexus conveys inflammatory immune signals into the brain, largely through alterations in the composition of the cerebrospinal fluid. Results In the present study we investigated the mouse choroid plexus gene expression profile, using microarray analyses, in response to a repeated inflammatory stimulus induced by the intraperitoneal administration of lipopolysaccharide every two weeks for a period of three months; mice were sacrificed 3 and 15 days after the last lipopolysaccharide injection. The data show that the choroid plexus displays a sustained response to the repeated inflammatory stimuli by altering the expression profile of several genes. From a total of 24,000 probes, 369 are up-regulated and 167 are down-regulated 3 days after the last lipopolysaccharide injection, while at 15 days the number decreases to 98 and 128, respectively. The pathways displaying the most significant changes include those facilitating entry of cells into the cerebrospinal fluid, and those participating in the innate immune response to infection. Conclusion These observations contribute to a better understanding of the brain response to peripheral inflammation and pave the way to study their impact on the progression of several disorders of the central nervous system in which inflammation is known to be implicated.

  11. On model selections for repeated measurement data in clinical studies.

    Science.gov (United States)

    Zou, Baiming; Jin, Bo; Koch, Gary G; Zhou, Haibo; Borst, Stephen E; Menon, Sandeep; Shuster, Jonathan J

    2015-05-10

    Repeated measurement designs have been widely used in various randomized controlled trials for evaluating long-term intervention efficacies. For some clinical trials, the primary research question is how to compare two treatments at a fixed time, using a t-test. Although simple, robust, and convenient, this type of analysis fails to utilize a large amount of collected information. Alternatively, the mixed-effects model is commonly used for repeated measurement data. It models all available data jointly and allows explicit assessment of the overall treatment effects across the entire time spectrum. In this paper, we propose an analytic strategy for longitudinal clinical trial data where the mixed-effects model is coupled with a model selection scheme. The proposed test statistics not only make full use of all available data but also utilize the information from the optimal model deemed for the data. The performance of the proposed method under various setups, including different data missing mechanisms, is evaluated via extensive Monte Carlo simulations. Our numerical results demonstrate that the proposed analytic procedure is more powerful than the t-test when the primary interest is to test for the treatment effect at the last time point. Simulations also reveal that the proposed method outperforms the usual mixed-effects model for testing the overall treatment effects across time. In addition, the proposed framework is more robust and flexible in dealing with missing data compared with several competing methods. The utility of the proposed method is demonstrated by analyzing a clinical trial on the cognitive effect of testosterone in geriatric men with low baseline testosterone levels. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Repeatability and reproducibility of ribotyping and its computer interpretation.

    Science.gov (United States)

    Lefresne, Gwénola; Latrille, Eric; Irlinger, Françoise; Grimont, Patrick A D

    2004-04-01

    Many molecular typing methods are difficult to interpret because their repeatability (within-laboratory variance) and reproducibility (between-laboratory variance) have not been thoroughly studied. In the present work, ribotyping of coryneform bacteria was the basis of a study involving within-gel and between-gel repeatability and between-laboratory reproducibility (two laboratories involved). The effect of different technical protocols, different algorithms, and different software for fragment size determination was studied. Analysis of variance (ANOVA) showed, within a laboratory, that there was no significant added variance between gels. However, between-laboratory variance was significantly higher than within-laboratory variance. This may be due to the use of different protocols. An experimental function was calculated to transform the data and make them compatible (i.e., erase the between-laboratory variance). The use of different interpolation algorithms (spline, Schaffer and Sederoff) was a significant source of variation in one laboratory only. The use of either Taxotron (Institut Pasteur) or GelCompar (Applied Maths) was not a significant source of added variation when the same algorithm (spline) was used. However, the use of Bio-Gene (Vilber Lourmat) dramatically increased the error (within laboratory, within gel) in one laboratory, while decreasing the error in the other laboratory; this might be due to automatic normalization attempts. These results were taken into account for building a database and performing automatic pattern identification using Taxotron. Conversion of the data considerably improved the identification of patterns irrespective of the laboratory in which the data were obtained.

  13. Factors associated with repeat induced abortion in Kenya.

    Science.gov (United States)

    Maina, Beatrice W; Mutua, Michael M; Sidze, Estelle M

    2015-10-12

    Over six million induced abortions were reported in Africa in 2008 with over two million induced abortions occurring in Eastern Africa. Although a significant proportion of women in the region procure more than one abortion during their reproductive period, there is a dearth of research on factors associated with repeat abortion. Data for this study come from the Magnitude and Incidence of Unsafe Abortion Study conducted by the African Population and Health Research Center in Kenya in 2012. The study used a nationally-representative sample of 350 facilities (level II to level VI) that offer post-abortion services for complications following induced and spontaneous abortions. A prospective morbidity survey tool was used by health providers in 328 facilities to collect information on socio-demographic charateristics, reproductive health history and contraceptive use at conception for all patients presenting for post-abortion services. Our analysis is based on data recorded on 769 women who were classified as having had an induced abortion. About 16 % of women seeking post abortion services for an induced abortion reported to have had a previous induced abortion. Being separated or divorced or widowed, having no education, having unwanted pregnancy, having 1-2 prior births and using traditional methods of contraception were associated with a higher likelihood of a repeat induced abortion. The findings point to the need to address the reasons why women with first time induced abortion do not have the necessary information to prevent unintended pregnancies and further induced abortions. Possible explanations linked to the quality of post-abortion family planning and coverage of long-acting methods should be explored.

  14. Repeatability and responsiveness of exercise tests in pulmonary arterial hypertension.

    Science.gov (United States)

    Mainguy, Vincent; Malenfant, Simon; Neyron, Anne-Sophie; Bonnet, Sébastien; Maltais, François; Saey, Didier; Provencher, Steeve

    2013-08-01

    Exercise tolerance in pulmonary arterial hypertension (PAH) is most commonly assessed by the 6-min walk test (6MWT). Whether endurance exercise tests are more responsive than the 6MWT remains unknown. 20 stable PAH patients (mean±sd age 53±15 years and mean pulmonary arterial pressure 44±16 mmHg) already on PAH monotherapy completed the 6MWT, the endurance shuttle walk test (ESWT) and the cycle endurance test (CET) before and after the addition of sildenafil citrate 20 mg three times daily or placebo for 28 days in a randomised double-blind crossover setting. Pre- or post-placebo tests were used to assess repeatability of each exercise test, whereas pre- or post-sildenafil citrate tests were used to assess their responsiveness. Sildenafil citrate led to placebo-corrected changes in exercise capacity of 18±25 m (p = 0.02), 58±235 s (p = 0.58) and 29±77 s (p = 0.09) for the 6MWT, the ESWT and the CET, respectively. The 6MWT was associated with a lower coefficient of variation between repeated measures (3% versus 18% versus 13%), resulting in a higher standardised response mean compared with endurance tests (0.72, 0.25 and 0.38 for the 6MWT, the ESWT and the CET, respectively). The 6MWT had the best ability to capture changes in exercise capacity when sildenafil citrate was combined with patients' baseline monotherapy, supporting its use as an outcome measure in PAH.

  15. Postural adaptations to repeated optic flow stimulation in older adults

    Science.gov (United States)

    O’Connor, Kathryn W.; Loughlin, Patrick J.; Redfern, Mark S.; Sparto, Patrick J.

    2008-01-01

    The purpose of this study is to understand the processes of adaptation (changes in within-trial postural responses) and habituation (reductions in between-trial postural responses) to visual cues in older and young adults. Of particular interest were responses to sudden increases in optic flow magnitude. The postural sway of 25 healthy young adults and 24 healthy older adults was measured while subjects viewed anterior-posterior 0.4 Hz sinusoidal optic flow for 45 s. Three trials for each of three conditions were performed: 1) constant 12 cm optic flow amplitude (24 cm peak-to-peak), 2) constant 4 cm amplitude (8 cm p-t-p), and 3) a transition in amplitude from 4 to 12 cm. The average power of head sway velocity (Pvel) was calculated for consecutive 5 s intervals during the trial to examine the changes in sway within and between trials. A mixed factor repeated measures ANOVA was performed to examine the effects of subject Group, Trial, and Interval on the Pvel. Pvel was greater in older adults in all conditions (p Pvel of the older adults decreased significantly between all 3 trials, but decreased only between trial 1 and 2 in young adults. While the responses of the young adults to the transition in optic flow from 4 to 12 cm did not significantly change, older adults had an increase in Pvel following the transition, ranging from 6.5 dB for the first trial to 3.4 dB for the third trial. These results show that older adults can habituate to repeated visual perturbation exposures; however, this habituation requires a greater number of exposures than young adults. This suggests aging impacts the ability to quickly modify the relative weighting of the sensory feedback for postural stabilization. PMID:18329878

  16. Development of repeated sprint ability in talented youth basketball players.

    Science.gov (United States)

    te Wierike, Sanne C M; de Jong, Mark C; Tromp, Eveline J Y; Vuijk, Pieter J; Lemmink, Koen A P M; Malina, Robert M; Elferink-Gemser, Marije T; Visscher, Chris

    2014-04-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14-19 years of age (16.1 ± 1.7 years). Players were observed on 6 occasions during the 2008-09 and 2009-10 seasons. Three following basketball-specific field tests were administered on each occasion: the shuttle sprint test for RSA, the vertical jump for lower body explosive strength (power), and the interval shuttle run test for interval endurance capacity. Height and weight were measured; body composition was estimated (percent fat, lean body mass). Multilevel modeling of RSA development curve was used with 32 players (16.0 ± 1.7 years) who had 2 or more observations. The 16 players (16.1 ± 1.8 years) measured on only 1 occasion were used as a control group to evaluate the appropriateness of the model. Age, lower body explosive strength, and interval endurance capacity significantly contributed to RSA (p ≤ 0.05). Repeated sprint ability improved with age from 14 to 17 years (p ≤ 0.05) and reached a plateau at 17-19 years. Predicted RSA did not significantly differ from measured RSA in the control group (p ≥ 0.05). The results suggest a potentially important role for the training of lower body explosive strength and interval endurance capacity in the development of RSA among youth basketball players. Age-specific reference values for RSA of youth players may assist basketball coaches in setting appropriate goals for individual players.

  17. Neonates’ responses to repeated exposure to a still face

    Science.gov (United States)

    Pilling, Karen; Watt, Rachel; Pal, Attila; Orvos, Hajnalka

    2017-01-01

    Aim The main aims of the study were to examine whether human neonates’ responses to communication disturbance modelled by the still-face paradigm were stable and whether their responses were affected by their previous experience with the still-face paradigm. Methods The still face procedure, as a laboratory model of interpersonal stress, was administered repeatedly, twice, to 84 neonates (0 to 4 day olds), with a delay of an average of 1.25 day. Results Frame-by-frame analysis of the frequency and duration of gaze, distressed face, crying, sleeping and sucking behaviours showed that the procedure was stressful to them both times, that is, the still face effect was stable after repeated administration and newborns consistently responded to such nonverbal violation of communication. They averted their gaze, showed distress and cried more during the still-face phase in both the first and the second administration. They also showed a carry-over effect in that they continued to avert their gaze and displayed increased distress and crying in the first reunion period, but their gaze behaviour changed with experience, in the second administration. While in the first administration the babies continued averting their gaze even after the stressful still-face phase was over, this carry-over effect disappeared in the second administration, and the babies significantly increased their gaze following the still-face phase. Conclusion After excluding explanations of fatigue, habituation and random effects, a self-other regulatory model is discussed as a possible explanation for this pattern. PMID:28771555

  18. The Vestibular Effects of Repeated Low-Level Blasts.

    Science.gov (United States)

    Littlefield, Philip D; Pinto, Robin L; Burrows, Holly L; Brungart, Douglas S

    2016-01-01

    The objective of this study was to use a prospective cohort of United States Marine Corps (USMC) instructors to identify any acute or long-term vestibular dysfunction following repeated blast exposures during explosive breaching training. They were assessed in clinic and on location during training at the USMC Methods of Entry School, Quantico, VA. Subjects received comprehensive baseline vestibular assessments and these were repeated in order to identify longitudinal changes. They also received shorter assessments immediately following blast exposure in order to identify acute findings. The main outcome measures were the Neurobehavioral Symptom Inventory, vestibular Visual Analog Scale (VAS) of subjective vestibular function, videonystagmography (VNG), vestibular evoked myogenic potentials (VEMP), rotary chair (including the unilateral centrifugation test), computerized dynamic posturography, and computerized dynamic visual acuity. A total of 11 breachers and 4 engineers were followed for up to 17 months. No acute effects or longitudinal deteriorations were identified, but there were some interesting baseline group differences. Upbeat positional nystagmus was common, and correlated (p<0.005) with a history of mild traumatic brain injury (mTBI). Several instructors had abnormally short low-frequency phase leads on rotary chair testing. This study evaluated breaching instructors over a longer test period than any other study, and the results suggest that this population appears to be safe from a vestibular standpoint at the current exposure levels. Upbeat positional nystagmus correlated with a history of mTBI in this population, and this has not been described elsewhere. The data trends also suggest that this nystagmus could be an acute blast effect. However, the reasons for the abnormally short phase leads seen in rotary chair testing are unclear at this time. Further investigation seems warranted.

  19. Social adversities in first-time and repeat prisoners.

    Science.gov (United States)

    Kjelsberg, Ellen; Friestad, Christine

    2008-11-01

    To explore possible systematic differences between prison inmates serving their first sentence and inmates having experienced previous incarcerations. It is hoped that a better knowledge of these issues will make us better equipped to meet the rehabilitation needs of our prisoners and decrease their risk of reoffending and reincarceration. In this cross-sectional study a randomly selected and nationally representative sample of 260 Norwegian prisoners, 100 serving their first sentence and 160 recidivists, was interviewed with special focus on childhood circumstances, education, work experience, and present social and economic situation. In addition their criminal records were collected from the National Crime Registry. In males multivariate analyses identified a number of variables independently and significantly associated with being a repeat offender. The odds for reincarceration increased significantly if the person fulfilled any one of the following criteria: having experienced the incarceration of a family member during childhood (OR = 3.6); having experienced childcare interventions during childhood (OR = 3.2); current drug abuse (OR = 2.6); current housing problems (OR = 2.3). In females only one strong correlation emerged: if the person had current drug problems the odds for being a recidivist increased substantially (OR = 10.9). While criminal reoffending and reincarceration seemed to be primarily associated with drug abuse in females, the childhood problems of male repeat offenders, compared with males serving their first sentence, indicate that these individuals' current multiple social and economic disadvantages were complex in origin and of long standing. Interventions aimed at preventing reoffending must take into account the gender differences demonstrated. ing at primary prevention, the negative effects associated with parental incarceration are crucial: how can one prevent the perpetuation of these problems from one generation to the next?

  20. Repeat Chlamydia trachomatis testing among heterosexual STI outpatient clinic visitors in the Netherlands: a longitudinal study.

    Science.gov (United States)

    Visser, Maartje; van Aar, Fleur; Koedijk, Femke D H; Kampman, Carolina J G; Heijne, Janneke C M

    2017-12-20

    Chlamydia infections are common in both men and women, are often asymptomatic and can cause serious complications. Repeat testing in high-risk groups is therefore indicated. In the Netherlands, guidelines on repeat chlamydia testing differ between testing facilities, and knowledge on repeat testing behaviour is limited. Here, we analyse the current repeat testing behaviour of heterosexual STI clinic visitors, and aim to identify groups for which repeat testing advice could be advantageous. Longitudinal surveillance data from all Dutch STI outpatient clinics were used, which included all STI clinic consultations carried out among heterosexual men and women between June 2014 and December 2015. Repeat testing was defined as returning to the same STI clinic between 35 days and 12 months after initial consultation. We calculated chlamydia positivity at repeat test stratified by initial test result and time between consultations. Logistic regression analyses were used to identify predictors of repeat testing, and predictors of having a chlamydia positive repeat test. In total, 140,486 consultations in 75,487 women and 46,286 men were available for analyses. Overall, 15.4% of women and 11.1% of men returned to the STI clinic within the study period. Highest chlamydia positivity at repeat test was seen 3-5 months after initial positive test. Among both women and men, repeat testing was associated with non-Western ethnicity, having had more than two sex partners in the past 6 months, reporting STI symptoms, having a history of STI, and having a chlamydia positive initial test. Among repeat testers, chlamydia positive repeat test was most strongly associated with younger age, followed by a chlamydia positive initial test. Repeat testing most often resulted in a positive test result among young heterosexuals (<25) and heterosexuals of any age with a chlamydia infection at the initial consultation. Further efforts are needed to determine optimal repeat testing strategies.