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Sample records for candidate xte j1650-500

  1. Evidence of Spin and Energy Extraction in a Galactic Black Hole Candidate: The XMM-Newton/EPIC-pn Spectrum of XTE J1650-500

    NASA Astrophysics Data System (ADS)

    Miller, J. M.; Fabian, A. C.; Wijnands, R.; Reynolds, C. S.; Ehle, M.; Freyberg, M. J.; van der Klis, M.; Lewin, W. H. G.; Sanchez-Fernandez, C.; Castro-Tirado, A. J.

    2002-05-01

    We observed the Galactic black hole candidate XTE J1650-500 early in its fall of 2001 outburst with the XMM-Newton European Photon Imaging pn Camera (EPIC-pn). The observed spectrum is consistent with the source having been in the ``very high'' state. We find a broad, skewed Fe Kα emission line that suggests the primary in this system may be a Kerr black hole and that indicates a steep disk emissivity profile that is hard to explain in terms of a standard accretion disk model. These results are quantitatively and qualitatively similar to those from an XMM-Newton observation of the Seyfert galaxy MCG -6-30-15. The steep emissivity in MCG -6-30-15 may be explained by the extraction and dissipation of rotational energy from a black hole with nearly maximal angular momentum or from material in the plunging region via magnetic connections to the inner accretion disk. If this process is at work in both sources, an exotic but fundamental general relativistic prediction may be confirmed across a factor of 106 in black hole mass. We discuss these results in terms of the accretion flow geometry in stellar-mass black holes and the variety of enigmatic phenomena often observed in the very high state.

  2. Disentangling the NIR/optical emission of the black hole XTE J1650-500 during outburst

    NASA Astrophysics Data System (ADS)

    Curran, P. A.; Chaty, S.; Zurita Heras, J. A.

    2012-11-01

    Context. While the sources of X-ray and radio emission in the different states of low-mass X-ray binaries are relatively well understood, the origin of the near-infrared (NIR) and optical emission is more often debated. It is likely that the NIR/optical flux originates from an amalgam of different emission regions, because it occurs at the intersecting wavelengths of multiple processes. Aims: We aim to identify the NIR/optical emission region(s) of one such low-mass X-ray binary and black hole candidate, XTE J1650-500, via photometric, timing, and spectral analyses. Methods: We present unique NIR/optical images and spectra, obtained with the ESO-New Technology Telescope, during the peak of the 2001 outburst of XTE J1650-500. Results: The data suggest that the NIR/optical flux is due to a combination of emission mechanisms including a significant contribution from X-ray reprocessing and, at early times in the hard state, a relativistic jet that is NIR/radio dim compared to similar sources. Conclusions: The jet of XTE J1650-500 is relatively weak compared to that of other black hole low-mass X-ray binaries, possibly because we observe as it is being "turned off" or quenched at the state transition. While there are several outliers to the radio-X-ray correlation of the hard state of low-mass X-ray binaries, XTE J1650-500 is the first example of an outlier to the NIR/optical-X-ray correlation. Based on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.

  3. High-Frequency Quasi-Periodic Oscillations in the Black Hole X-Ray Transient XTE J1650-500

    NASA Technical Reports Server (NTRS)

    Holman, Jeroen; Klein-Wolt, Marc; Rossi, Sabrina; Miller, Jon M.; Wijnands, Rudy; Belloni, Tomaso; VanDerKlis, Michiel; Lewin, Walter H. G.

    2003-01-01

    We report the detection of high-frequency variability in the black hole X-ray transient XTE 51650-500. A quasi-periodic oscillation (QPO) was found at 250 Hz during a transition from the hard to the soft state. We also detected less coherent variability around 50 Hz that disappeared when the 250 Hz QPO showed up. There are indications that when the energy spectrum hardened the QPO frequency increased from approx. 110 to approx. 270 Hz, although the observed frequencies are also consistent with being 1 : 2 : 3 harmonics of each other. Interpreting the 250 Hz as the orbital frequency at the innermost stable orbit around a Schwarzschild black hole leads to a mass estimate of 8.2 solar mass. The spectral results by Miller et al., which suggest considerable black hole spin, would imply a higher mass.

  4. Evidence of Spin and Energy Extraction in a Galactic Black Hole Candidate: The XMM-NEWTON/EPIC SPECTRUM of XTE 11650-500

    NASA Technical Reports Server (NTRS)

    Miller, J. M.; Fabian, A. C.; Wunands, R.; Reynolds, C. S.; Ehle, M.; Freyberg, M. J.; VanDerKlis, M.; Lewin, W. H. G.; Sanchez-Fernandez, C.; Castro-Tirado, A. J.

    2002-01-01

    We observed the Galactic black hole candidate XTE J1650-500 early in its fall of 2001 outburst with the XMM-Newton European Photon Imaging pn Camera (EPIC-pn). The observed spectrum is consistent with the source having been in the very high state. We h d a broad, skewed Fe Kar emission line that suggests the primary in this system may be a Kerr black hole and that indicates a steep disk emissivity profile that is hard to explain in terms of a standard accretion disk model. These results are quantitatively and qualitatively similar to those from an XMM-Newton observation of the Seyfert galaxy MCG -6-30-15. The steep emissivity in MCG -6-30-15 may be explained by the extraction and dissipation of rotational energy from a black hole with nearly maximal angular momentum or from material in the plunging region via magnetic connections to the inner accretion disk. If this process is at work in both sources, an exotic but fundamental general relativistic prediction may be confirmed across a factor of l0(exp 6) in black hole mass. We discuss these results in terms of the accretion flow geometry in stellar-mass black holes and the variety of enigmatic phenomena often observed in the very high state.

  5. X-Ray Bursts from the Transient Magnetar Candidate XTE J1810-197

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa; Woods, Peter M.; Gavriil, Fotis P.; Kaspi, Victoria M.; Roberts, Mallory S. E.; Ibrahim, Alaa; Markwardt, Craig B.; Swank, Jean H.; Finger, Mark H.

    2005-01-01

    We have discovered four X-ray bursts, recorded with the Rossi X-ray Timing Explorer Proportional Counter Array between 2003 September and 2004 April, that we show to originate from the transient magnetar candidate XTE 51810-197. The burst morphologies consist of a short spike or multiple spikes lasting approx. 1 s each followed by extended tails of emission where the pulsed flux from XTE 51810-197 is significantly higher. The burst spikes are likely correlated with the pulse maxima, having a chance probability of a random phase distribution of 0.4%. The burst spectra are best fit to a blackbody with temperatures 4-8 keV, considerably harder than the persistent X-ray emission. During the X-ray tails following these bursts, the temperature rapidly cools as the flux declines, maintaining a constant emitting radius after the initial burst peak. The temporal and spectral characteristics of these bursts closely resemble the bursts seen from 1E 1048.1-5937 and a subset of the bursts detected from 1E 2259+586, thus establishing XTE J1810-197 as a magnetar candidate. The bursts detected from these three objects are sufficiently similar to one another, yet si,g&cantly differe2t from those seen from soft gamma repeaters, that they likely represent a new class of bursts from magnetar candidates exclusive (thus far) to the anomalous X-ray pulsar-like sources.

  6. Multiwavelength Observations of the Black Hole Candidate XTE J1550-564 during the 2000 Outburst

    NASA Astrophysics Data System (ADS)

    Jain, Raj K.; Bailyn, Charles D.; Orosz, Jerome A.; McClintock, Jeffrey E.; Remillard, Ronald A.

    2001-06-01

    We report optical, infrared, and X-ray light curves for the outburst, in 2000, of the black hole candidate XTE J1550-564. We find that the start of the outburst in the H and V bands precedes that seen in the Rossi X-Ray Timing Explorer All-Sky Monitor by 11.5+/-0.9 and 8.8+/-0.6 days, respectively; a similar delay has been observed in two other systems. About 50 days after the primary maxima in the VIH light curves, we find secondary maxima, most prominently in H. This secondary peak is absent in the X-ray light curve but coincides with a transition to the low/hard state. We suggest that this secondary peak may be due to nonthermal emission associated with the formation of a jet.

  7. NIR Imaging of the Candidate Black Hole Transient XTE J1652-453

    NASA Astrophysics Data System (ADS)

    Reynolds, Mark; Callanan, Paul; Nagayama, Takahiro

    2009-07-01

    We obtained a series of 300s exposures in the J, H & K' bands of the field of the candidate black hole transient XTE J1652-453 (ATEL #2107) using the Sirius simultaneous 3 channel NIR imager mounted on the Infrared Survey Facility 1.4m telescope at SAAO. Within the Swift error circle (ATEL #2120), there are at least two objects visible in the K' image (see chart): Star A: 16 52 20.4 -45 20 38.4, K' = 17.0 +/- 0.3 and the other at Star B: 16 52 20.3 -45 20 39.9, K' = 16.9 +/- 0.3 where the positional error is 0.5''.

  8. Long-Term Spectral and Timing Behavior of the Black Hole Candidate XTE J1908+094

    NASA Technical Reports Server (NTRS)

    Gogus, Ersin; Finger, Mark H.; Kouveliotou, Chryssa; Woods, Peter M.; Patel, Sandeep K.; Ruppen, Michael; Swank, Jean H.; Markwardt, Craig B.; VanDerKlis, Michiel

    2004-01-01

    We present the long-term X-ray light curves and detailed spectral and timing analyses of XTE J1908+094 using the Rossi X-Ray Timing Explorer Proportional Counter Array observations covering two outbursts in 2002 and early 2003. At the onset of the first outburst, the source was found in a spectrally low/hard state lasting for approx.40 days, followed by a 3 day long transition to the high/soft state. The source flux (in 2- 10 keV) reached approx.100 mcrab on 2002 April 6, then decayed rapidly. In power spectra, we detect strong band-limited noise and varying low- frequency quasi-periodic oscillations that evolved from approx.0.5 to approx.5 Hz during the initial low/hard state of the source. We find that the second outburst closely resembled the spectral evolution of the first. The X-ray transient s overall outburst characteristics led us to classify XTE J1908+094 as a black hole candidate. Here we also derive precise X-ray position of the source using Chandra observations that were performed during the decay phase of the first outburst and following the second outburst.

  9. Discovery and Monitoring of a New Black Hole Candidate XTE J1752-223 with RXTE: RMS Spectrum Evolution, BH Mass and the Source Distance

    NASA Technical Reports Server (NTRS)

    Shaposhinikov, Nikolai; Markwardt, Craig; Swank, Jean; Krimm, Hans

    2010-01-01

    We report on the discovery and monitoring observations of a new galactic black hole candidate XTE J1752-223 by Rossi X-ray Timing Explorer (RXTE). The new source appeared on the X-ray sky on October 21 2009 and was active for almost 8 months. Phenomenologically, the source exhibited the low-hard/highsoft spectral state bi-modality and the variability evolution during the state transition that matches standard behavior expected from a stellar mass black hole binary. We model the energy spectrum throughout the outburst using a generic Comptonization model assuming that part of the input soft radiation in the form of a black body spectrum gets reprocessed in the Comptonizing medium. We follow the evolution of fractional root-mean-square (RMS) variability in the RXTE/PCA energy band with the source spectral state and conclude that broad band variability is strongly correlated with the source hardness (or Comptonized fraction). We follow changes in the energy distribution of rms variability during the low-hard state and the state transition and find further evidence that variable emission is strongly concentrated in the power-law spectral component. We discuss the implication of our results to the Comptonization regimes during different spectral states. Correlations of spectral and variability properties provide measurements of the BH mass and distance to the source. The spectral-timing correlation scaling technique applied to the RXTE observations during the hardto- soft state transition indicates a mass of the BH in XTE J1752-223 between 8 and 11 solar masses and a distance to the source about 3.5 kiloparsec.

  10. X-ray timing and spectral observations of galactic black hole candidate XTE J1550-564 during outburst

    NASA Astrophysics Data System (ADS)

    Reilly, Kaice Theodore

    2003-09-01

    The timing and spectral properties of the soft X-ray transient (SXT) and microquasar XTE J1550-564 during outburst are studied, emphasizing observations made by the Unconventional Stellar Aspect (USA) Experiment. USA data show a low-frequency quasi-periodic oscillation (LFQPO) with a centroid frequency that tends to increase with increasing flux and a fractional rms amplitude which is correlated with the USA hardness ratio. Several high- frequency quasi-periodic oscillations (HFQPOs) were detected by RXTE, during periods where the LFQPO is seen to be weakening or not detectable at all. The evolution of the USA hardness ratio with time and source flux is examined. The hardness-intensity diagram shows counterclockwise cyclical evolution and possibly indicates the presence of two independent accretion flows: a geometrically thin, optically thick accretion disk and a hot sub-Keplerian flow. A model for production of the LFQPO in XTE J1550-564 is proposed, assuming that the LFQPO is a result of acoustic oscillations in a hot sub-Keplerian transition layer (TL). Under this acoustic oscillation model (AOM), the TL is an acoustic cavity having an outer boundary at RTL, where R TL ≈ Rinner, with Rinner being the radius of the accretion disk inner edge. TL resonance is interpreted as a mechanism for the LFQPO and the eigenfrequencies are associated with the LFQPO frequencies, ν LFQPO. This LFQPO mechanism requires the presence of a TL, capable of inverse-Compton scattering, with RTL regulated by a cool Keplerian accretion disk. Support for the AOM is provided by the correlation of the LFQPO percent rms amplitude with the USA hardness ratio, and other correlations and anti-correlations found in the USA, RXTE and BATSE observations. LFQPO data show increasing rms amplitude with increasing high energy flux and increasing νLFQPO with increasing low energy flux. These observations indicate that ν LFQPO is set by the accretion disk inner edge. The spectrally inferred Rinner

  11. The black hole candidate XTE J1752-223 towards and in quiescence: optical and simultaneous X-ray-radio observations

    NASA Astrophysics Data System (ADS)

    Ratti, E. M.; Jonker, P. G.; Miller-Jones, J. C. A.; Torres, M. A. P.; Homan, J.; Markoff, S.; Tomsick, J. A.; Kaaret, P.; Wijnands, R.; Gallo, E.; Özel, F.; Steeghs, D. T. H.; Fender, R. P.

    2012-07-01

    We present optical, X-ray and radio observations of the black hole transient (BHT) XTE J1752-223 towards and in quiescence. Optical photometry shows that the quiescent magnitude of XTE J1752-223 is fainter than 24.4 mag in the i' band. A comparison with measurements of the source during its 2009-2010 outburst shows that the outburst amplitude is more than 8 mag in the i' band. Known X-ray properties of the source combined with the faintness of the quiescence optical counterpart and the large outburst optical amplitude point towards a short orbital-period system (Porb≲ 6.8 h) with an M type (or later) mass donor, at a distance of 3.5 ≲d≲ 8 kpc. Simultaneous X-ray and radio data were collected with Chandra and the Expanded Very Large Array (EVLA), allowing constraints to be placed on the quiescent X-ray and radio flux of XTE J1752-223. Furthermore, using data covering the final stage of the outburst decay, we investigated the low-luminosity end of the X-ray-radio correlation for this source and compared it with other BHTs. We found that XTE J1752-223 adds to the number of outliers with respect to the 'standard' X-ray-radio luminosity relation. Furthermore, XTE J1752-223 is the second source, after the BHT H1743-322, that shows a transition from the region of the outliers towards the 'standard' correlation at low luminosity. Finally, we report on a faint, variable X-ray source we discovered with Chandra at an angular distance of ˜2.9 arcsec to XTE J1752-223 and at a position angle consistent with that of the radio jets previously observed from the BHT. We discuss the possibility that we detected X-ray emission associated with a jet from XTE J1752-223.

  12. Fermi arc electronic structure and Chern numbers in the type-II Weyl semimetal candidate MoxW1 -xTe2

    NASA Astrophysics Data System (ADS)

    Belopolski, Ilya; Xu, Su-Yang; Ishida, Yukiaki; Pan, Xingchen; Yu, Peng; Sanchez, Daniel S.; Zheng, Hao; Neupane, Madhab; Alidoust, Nasser; Chang, Guoqing; Chang, Tay-Rong; Wu, Yun; Bian, Guang; Huang, Shin-Ming; Lee, Chi-Cheng; Mou, Daixiang; Huang, Lunan; Song, You; Wang, Baigeng; Wang, Guanghou; Yeh, Yao-Wen; Yao, Nan; Rault, Julien E.; Le Fèvre, Patrick; Bertran, François; Jeng, Horng-Tay; Kondo, Takeshi; Kaminski, Adam; Lin, Hsin; Liu, Zheng; Song, Fengqi; Shin, Shik; Hasan, M. Zahid

    2016-08-01

    It has recently been proposed that electronic band structures in crystals can give rise to a previously overlooked type of Weyl fermion, which violates Lorentz invariance and, consequently, is forbidden in particle physics. It was further predicted that MoxW1 -xTe2 may realize such a type-II Weyl fermion. Here, we first show theoretically that it is crucial to access the band structure above the Fermi level ɛF to show a Weyl semimetal in MoxW1 -xTe2 . Then, we study MoxW1 -xTe2 by pump-probe ARPES and we directly access the band structure >0.2 eV above ɛF in experiment. By comparing our results with ab initio calculations, we conclude that we directly observe the surface state containing the topological Fermi arc. We propose that a future study of MoxW1 -xTe2 by pump-probe ARPES may directly pinpoint the Fermi arc. Our work sets the stage for the experimental discovery of the first type-II Weyl semimetal in MoxW1 -xTe2 .

  13. XTE Science Briefing from KSCNF

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The X-ray Timing Explorer (XTE), launched on Dec. 30, 1995, is a Satellite that observes the fast-moving, high-energy worlds of black holes, neutron stars, x-ray pulsars and bursts of X-rays that light up the sky and then disappear forever. This videotape presents a pre-launch science briefing to the press by a few of the scientist and managers associated with the XTE satellite. The moderator for the press briefing is Jim Sahli, from the Public Affairs Office at Goddard Space Flight Center (GSFC). He introduces Alan Bunner, of the High Energy Astrophysics at NASA Headquarters; Fred Lamb, from the University of Illinois; Richard Mashotzky, X Ray Scientist at GSFC; Rick Rothschild, Principal Investigator from the University of California at San Diego; and Dale Schultz, the XTE project manager at GSFC. Dr. Bunner explains the electromagnetic spectrum, the placement of x-rays and the importance of the XTE observations to a better understanding of the Universe. Dr. Lamb, explains the difference between white dwarfs, neutron stars and black holes, and the type of observations that the XTE will give to a further understanding of these phenomena. Dr. Mashotzky expands the viewpoint to beyond the galaxy, and explains the interests of scientists who hope to use XTE to further study Quasars and Active Galactic Nuclei. Dr. Rothschild reviews some of the features of XTE, using a diagram to show the features of interest, such as the X ray Telescopes, and the collecting Proportional Counter Array (PCA.) Mr. Schultz presents a videotape tour of the XTE, in which he shows the scientific instruments and the other features of the satellite. In this tour, the source of each of the instruments is noted. Questions from the members of the press are then fielded. Many of the questions are about the cost of the XTE and any problems that are anticipated in regards to the launch.

  14. XTE J1908+094

    NASA Technical Reports Server (NTRS)

    Woods, P. M.; Kouveliotou, C.; Finger, M. H.; Gogus, E.; Swank, J.; Markwardt, C.; Strohmayer, T.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Goddard Space Flight Center reports the serendipitous discovery of a new x-ray transient, XTE J1908+094, in RXTE (Rossi X-ray Timing Explorer) PCA (Proportional Counter Array) observations of the soft-gamma-ray repeater SGR 1900+14, triggered following the burst activity on Feb. 17-18 (GCN 1253). These observations failed to detect the 5.2-s SGR pulsations, pointing towards a possible new source as the origin of the high x-ray flux. An RXTE PCA scan of the region around SGR 1900+14 on Feb. 21 was consistent with emission only from known sources (and no new sources). However, the scans required SGR 1900+14 to be 20 times brighter than its quiescent flux level (GCN 1256). A Director's Discretionary Time Chandra observation on Mar. 11 showed that the SGR was quiescent and did not reveal any new source within the Chandra ACIS (Advanced CCD (charge coupled device) Imaging Spectrometer) field-of-view. A subsequent RXTE PCA scan on Mar. 17, taken in combination with the first scan, required that a new source be included in the fit. The best-fit position is R.A. 19h 08m 50s, Decl. = +9 22 deg .5 (equinox J2000.0; estimated 2 deg systematic error radius), or approximately 24 deg away from the SGR source. The source spectrum (2-30 kev) can be best fit with a power-law function including photoelectric absorption (column density N_h = 2.3 x 10(exp 22), photon index = 1.55). Iron line emission is present, but may be due to the Galactic ridge. Between Feb. 19 and Mar. 17, the source flux (2-10 keV) has risen from 26 to 64 mCrab. The power spectrum is flat between 1 mHz and 0.1 Hz, falling approximately as 1/f**0.5 up to 1 Hz. At 1 Hz is seen a broad quasiperiodic oscillation peak and a break to a 1/f**2 power law, which continues to 4 Hz. The fractional rms (root mean square) amplitude from 1 mHz to 4 Hz is 43 percent. No coherent pulsations are seen between 0.001 and 1024 Hz. The authors conclude that XTE J1908+094 is a new blackhole candidate.

  15. Doppler Imaging of Black Hole SYSTEMS:XTE J1118+480.

    NASA Astrophysics Data System (ADS)

    Callanan, Paul; Perres-Torres, Manuel; Garcia, Michael

    We present time-resolved spectroscopy of the black-hole candidate XTE J1118+480 obtained during its approach to quiescence. Doppler imaging of the intense Hα line shows persistent emission with an origin in the gas stream/hotspot. In addition the Doppler maps show enhanced emission in the +Vx -Vy quadrant clearing incompatible with a stream/hotspot origin. We favour a non-uniform disk intensity distribution due to tidal effects as the origin of this emission. We compare our map with that of XTE J1118+480 in outburst as well as with those of other transient systems in quiescence

  16. Delta XTE Launch Activities (Scrub #2)

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This NASA Kennedy Space Center video presents Delta XTE (X-Ray Timing Explorer) launch activities on 12/11/95. The launch was rescheduled for next weekend due to out of limit upper level wind conditions.

  17. On the modulation of low-frequency quasi-periodic oscillations in black hole transients

    NASA Astrophysics Data System (ADS)

    Pawar, Devraj D.; Motta, Sara; Shanthi, K.; Bhattacharya, Dipankar; Belloni, Tomaso

    2015-04-01

    We studied the properties of the low-frequency quasi-periodic oscillations detected in a sample of six black hole candidates (XTE J1550-564, H 1743-322, XTE J1859+226, 4U 1630-47, GX 339-4, XTE J1650-500) observed by the Rossi XTE satellite. We analysed the relation between the full width at half-maximum and the frequency of all the narrow peaks detected in power density spectra where a type-C QPO is observed. Our goal was to understand the nature of the modulation of the signal by comparing the properties of different harmonic peaks in the power density spectrum. We find that for the sources in our sample the width of the fundamental and of the first harmonic are compatible with a frequency modulation, while that of the sub-harmonic is independent of frequency, possibly indicating the presence of an additional modulation in amplitude. We compare our results with those obtained earlier from GRS 1915+105 and XTE J1550-564.

  18. Delta XTE Spacecraft Arrives at CCAS Skid Strip

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Footage shows the U.S Air Force Aircraft "Air Mobility Command" approaching, and landing at the Cape Canaveral Air Station Skid Strip (CCAS). The truck carrying the Delta XTE Spacecraft is also shown as it leaves the Air Mobility Command.

  19. Optical observations of XTE J1709-267

    NASA Astrophysics Data System (ADS)

    Wiersema, K.; Higgins, A. B.

    2016-06-01

    The X-ray binary XTE J1709-267 was recently found to be in outburst again by MAXI (Atel #9108). We observed this source using EFOSC2 on the ESO NTT. At 02:33 UT on 23 June 2016, the source was detected at V=17.9 mag. This is several magnitudes brighter than the brightness in quiescence (Jonker et al. 2004, MNRAS 354, 666).

  20. A new outburst of XTE J1739-285

    NASA Astrophysics Data System (ADS)

    Maccarone, Thomas J.; Bandyopadhyay, Reba; Kennea, Jamie

    2012-09-01

    With our program of Swift monitoring of the Galactic Bulge region (Atel #4109), we detect renewed activity of the X-ray binary XTE J1739-285. Using the pipeline of Phil Evans (Evans et al. 2007, A&A, 469, 379), we find that the source count rate is about 34 counts/sec in data taken on 4 September from 5:33 to 12:02 UT, with 372 seconds of exposure time on source. We note that the source is heavily piled up, since the data were taken in photon counting mode as part of an imaging survey and hence the count rate should be taken with caution.

  1. A Pointed RXTE Observation of XTE J1817-330

    NASA Astrophysics Data System (ADS)

    Miller, J. M.; Homan, J.; Steeghs, D.; Torres, M. A. P.; Wijnands, R.

    2006-02-01

    We report on a pointed RXTE observation of XTE J1817-330, obtained on 2006-02-13 at 08:10:40 UT. After standard screening, the net good time for the PCA was 9.6 ksec, and the net good time for the HEXTE (cluster A) was 3.0 ksec. Joint fits were made to the PCU-2 and HEXTE-A spectra on the 2.8-25.0 keV and 20.0-200.0 keV range, respectively, with XSPEC. For a variety of continuum spectral models, a low column density is implied.

  2. Observational Signatures of Black Holes: Spectral and Temporal Features of XTE J1550-564

    NASA Technical Reports Server (NTRS)

    Titarchuk, Lev; Shrader, C. R.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    The theoretical predictions of the converging inflow, or Bulk-Motion Comptonization model are discussed and some predictions are compared to X- and gamma-ray observations of the high-soft state of Galactic black hole candidate XTE J1550+564. The approx. 10(exp 2)-Hz QPO phenomenon tends to be detected in the high-state at times when the bolometric luminosity surges and the hard-powerlaw spectral component is dominant. Furthermore, the power in these features increases with energy. We offer interpretation of this phenomenon, as oscillations of the innermost part of the accretion disk, which in turn supplies the seed photons for the converging inflow where the hard power-law is formed through Bulk Motion Comptonization (BMC). We further argue that the noted lack of coherence between intensity variations of the high-soft-state low and high energy bands is a natural consequence of our model, and that a natural explanation for the observed hard and soft lag phenomenon is offered. In addition, we address some criticisms of the BMC model supporting our claims with observational results.

  3. Relations between X-ray timing features and spectral parameters of Galactic black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Stiele, H.; Belloni, T. M.; Kalemci, E.; Motta, S.

    2013-03-01

    We present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX 339-4, H1743-322 and XTE J1650-500, as the Rossi X-ray Timing Explorer observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the High Energy X-ray Timing Experiment detector and select observations that show a certain type of quasi-periodic oscillations (QPOs; type-C). The spectral parameters are derived using the empirical convolution model SIMPL to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive correlation between photon index and centroid frequency of the QPOs and reveal an anticorrelation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the `sombrero' geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follows a general track, independent of individual outbursts.

  4. Delta XTE Spacecraft Solar Panel Deployment, Hangar AO at Cape Canaveral Air Station

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The footage shows technicians in the clean room checking and adjusting the deployment mechanism of the solar panel for XTE spacecraft. Other scenes show several technicians making adjustments to software for deployment of the solar panels.

  5. Swift Detects Likely X-ray Burst from XTE J1701-407

    NASA Astrophysics Data System (ADS)

    Markwardt, C. B.; Cummings, J.; Krimm, H.

    2008-07-01

    XTE J1701-407 was discovered in June 2008 by RXTE PCA scans (Markwardt et al., ATEL #1569) and Swift follow-up observations (Degenaar et al., ATEL #1572). Recently Swift BAT triggered on an X-ray flare from the same source (Barthelmy et al., GCN Circ. #7985). In this telegram we report on BAT results for the XTE J1701-407 flare, which we speculate is a thermonuclear X-ray burst from a neutron star.

  6. Corrected Coordinates for the Possible OC to XTE J1550-56

    NASA Astrophysics Data System (ADS)

    Orosz, Jerome; Bailyn, Charles; Jain, Raj

    1998-09-01

    There was a slight error in the coordinates of the possible optical counterpart to XTE J1550-56 we reported in our previous telegram. The correct J2000 coordinates are RA = 15:50:58.78, DEC = -56:28:35.0. The coordinates printed on the finding chart available at http://www.astro.psu.edu/users/orosz/xte.html has been corrected (the arrow points to the correct object in any case). We regret this error.

  7. Discovery of a Transient Magnetar: XTE J1810-197

    NASA Technical Reports Server (NTRS)

    Ibrahim, Alaa I.; Markwardt, Craig B.; Swank, Jean H.; Ransom, Scott; Roberts, Mallory; Kaspi, Victoria; Woods, Peter M.; Safi-Harb, Samar; Balman, Solen; Parke, William C.

    2004-01-01

    We report the discovery of a new X-ray pulsar, XTE J1810-197, that was serendipitously discovered on 2003 July 15 by the Rossi X-Ray Timing Explorer (RXTE) while observing the soft gamma repeater SGR 1806-20. The pulsar has a 5.54 s spin period, a soft X-ray spectrum (with a photon index of approx. = 4). and is detectable in earlier RXTE observations back to 2003 January but not before. These show that a transient outburst began between 2002 November 17 and 2003 January 23 and that the source's persistent X-ray flux has been declining since then. The pulsar exhibits a high spin-down rate P approx.= l0(exp -11) s/s with no evidence of Doppler shifts due to a binary companion. The rapid spin-down rate and slow spin period imply a supercritical characteristic magnetic field B approx. = 3 x l0(exp 14) G and a young age tau less than or = 7600 yr. Follow-up Chandra observations provided an accurate position of the source. Within its error radius, the 1.5 m Russian-Turkish Optical Telescope found a limiting magnitude R(sub c) = 21.5. All such properties are strikingly similar to those of anomalous X-ray pulsars ad soft gamma repeaters, providing strong evidence that the source is a new magnetar. However, archival ASCA and ROSAT observations found the source nearly 2 orders of magnitude fainter. This transient behavior and the observed long-term flux variability of the source in absence of an observed SGR-like burst activity make it the first confirmed transient magnetar and suggest that other neutron stars that share the properties of XTE 51810- 197 during its inactive phase may be unidentified transient magnetars awaiting detection via a similar activity. This implies a larger population of magnetars than previously surmised and a possible evolutionary connection between magnetars and other neutron star families. Subject headings: pulsars: general -pulsars: individual (XTE 51810- 197) - stars: magnetic fields -

  8. Discovery and Photometric Observation of the Optical Counterpart of a Possible Galactic Halo X-Ray Transient, XTE J1118+480

    NASA Astrophysics Data System (ADS)

    Uemura, Makoto; Kato, Taichi; Matsumoto, Katsura; Yamaoka, Hitoshi; Takamizawa, Kesao; Sano, Yasuo; Haseda, Katsumi; Cook, Lewis M.; Buczynski, Denis; Masi, Gianluca

    2000-08-01

    We discovered an optical counterpart of about 13 mag of a soft X-ray transient, XTE J1118+480 on 2000 March 30. We performed astrometry and provided an accurate position of R.A. = 11h18m10.85s85, Decl. = +48deg02'12.9{' '}. The outbursting object has been identified with a 18.8 mag star in the USNO catalog. Our pre-discovery data shows another outburst during 2000 January, again coinciding with an outburst detected in X-rays. Through CCD time-series photometry, we found the presence of a periodic variation with an amplitude of 0.055 mag and a period of 0.17078 \\pm 0.00004 d$, which we consider to be a promising candidate of the orbital period. Because of the high galactic latitude and faint quiescence magnitude of 18.8, XTE J1118+480 is possibly the first firmly identified black hole candidate X-ray transient in the galactic halo.

  9. Looking for black-holes in X-ray binaries with XMM-Newton: XTE J1817-330 and XTE J1856+053

    SciTech Connect

    Sala, Gloria; Greiner, Jochen; Primak, Natalia

    2008-10-08

    The X-ray binary XTE J1817-330 was discovered in outburst on 26 January 2006 with RXTE/ASM. One year later, another X-ray transient discovered in 1996, XTE J1856+053, was detected by RXTE during a new outburst on 28 February 2007. We triggered XMM-Newton target of opportunity observationson these two objects to constrain their parameters and search for a stellar black holes. We summarize the properties of these two X-ray transients and show that the soft X-ray spectra indicate indeed the presence of an accreting stellar black hole in each of the two systems.

  10. EVIDENCE OF LIGHT-BENDING EFFECTS AND ITS IMPLICATION FOR SPECTRAL STATE TRANSITIONS

    SciTech Connect

    Reis, R. C.; Miller, J. M.; Reynolds, M. T.; Fabian, A. C.; Walton, D. J.; Steiner, J. F.; Cackett, E.

    2013-01-20

    It has long been speculated that the nature of the hard X-ray corona may be an important second driver of black hole state transitions, in addition to the mass accretion rate through the disk. However, a clear physical picture of coronal changes has not yet emerged. We present results from a systematic analysis of Rossi X-Ray Timing Explorer observations of the stellar-mass black hole binary XTE J1650-500. All spectra with significant hard X-ray detections were fit using a self-consistent, relativistically blurred disk reflection model suited to high ionization regimes. Importantly, we find evidence that both the spectral and timing properties of black hole states may be partially driven by the height of the X-ray corona above the disk, and related changes in how gravitational light bending affects the corona-disk interaction. Specifically, the evolution of the power-law, thermal disk, and relativistically convolved reflection components in our spectral analysis indicates that: (1) the disk inner radius remains constant at r {sub in} =1.65 {+-} 0.08 GM/c {sup 2} (consistent with values found for the ISCO of XTE J1650-500 in other works) throughout the transition from the brighter phases of the low-hard state to the intermediate states (both the hard-intermediate and soft-intermediate), through to the soft state and back; (2) the ratio between the observed reflected X-ray flux and power-law continuum (the 'reflection fraction', R) increases sharply at the transition between the hard-intermediate and soft-intermediate states ('ballistic' jets are sometimes launched at this transition); (3) both the frequency and coherence of the high-frequency quasi-periodic oscillations observed in XTE J1650-500 increase with R. We discuss our results in terms of black hole states and the nature of black hole accretion flows across the mass scale.

  11. Delta XTE Launch Activities and Scrub (Anomaly) at Cape Canaveral Air Station Complex 17

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This NASA Kennedy Space Center video presents launch activities of the Delta X-ray Timing Explorer and scrub aboard a McDonnell Douglas Delta II rocket from Complex 17. The primary objective of the Delta XTE is to study time variability and broadband spectral phenomena in the X-ray emission from astronomical sources. XTE is designed for a required lifetime of two years with a goal of five years and will be inserted into a low-Earth circular orbit at an altitude of 600 km. The launch was postponed due to unfavorable wind conditions aloft.

  12. LOW-FREQUENCY OSCILLATIONS IN XTE J1550-564

    SciTech Connect

    Rao Fengyun; Belloni, Tomaso; Stella, Luigi; Zhang Shuangnan; Li Tipei E-mail: tomaso.belloni@brera.inaf.i

    2010-05-10

    We present the results of a timing analysis of the low-frequency quasi-periodic oscillation (QPO) in the Rossi X-Ray Timing Explorer data of the black hole binary XTE J1550-564 during its 1998 outburst. The QPO frequency is observed to vary on timescales between {approx}100 s and days, correlated with the count rate contribution from the optically thick accretion disk: we studied this correlation and discuss its influence on the QPO width. In all observations, the quality factors ({nu}{sub 0}/FWHM) of the fundamental and second harmonic peaks were observed to be consistent, suggesting that the quasi-periodic nature of the oscillation is due to frequency modulation. In addition to the QPO and its harmonic peaks, a new 1.5{nu} component was detected in the power spectra. This component is broad, with a quality factor of {approx}0.6. From this, we argue that the peak observed at half the QPO frequency, usually referred to as 'sub-harmonic', could be the fundamental frequency, leading to the sequence 1:2:3:4. We also studied the energy dependence of the timing features and conclude that the two continuum components observed in the power spectrum, although both more intense at high energies, show a different dependence on energy. At low energies, the lowest-frequency component dominates, while at high energies the higher-frequency one has a higher fractional rms. An interplay between these two components was also observed as a function of their characteristic frequency. In this source, the transition between the low/hard state and the hard-intermediate state appears to be a smooth process.

  13. The 2002 Outburst of the Millisecond Accreting Pulsar XTE J1751-305

    NASA Astrophysics Data System (ADS)

    Markwardt, C. B.; Swank, J. H.

    2002-12-01

    The millisecond accreting pulsar XTE J1751--305 was discovered in the galactic bulge region by the RXTE PCA in early 2002. It is one of only a handful of now-known millisecond pulsars that are presumably spinning up by mass accretion (along with SAX J1808.4--3658 and XTE J0929--314). We will present an analysis of the complete outburst of XTE J1751--305, including spectroscopy and timing. The outburst followed a similar track to the first known millisecond accreting pulsar, SAX J1808.4--3658, with a fast rise, exponential decay (time constant ~ 7 day), and a sudden cut-off. Over the outburst, the energy spectral shape remained essentially constant, and showed no strong line features. Aside from the pulsations, XTE J1751--305 also exhibited lower frequency fluctuations in the power spectrum, which are typical of low mass X-ray binaries. While there appears to be no strong kiloHertz quasiperiodic oscillations, there is some evidence for a weak and broad power spectral excess feature centered on a few hundred Hertz.

  14. Further comments on segregation during Bridgman growth of Cd(x)Hg(1-x)Te

    NASA Technical Reports Server (NTRS)

    Lehoczky, S. L.; Szofran, F. R.

    1984-01-01

    The authors comment on recent papers published by Capper et al. (1983) and Jones et al. (1983) which report and discuss the variation of composition with axial position in Bridgman-grown Cd(x)Hg(1-x)Te alloys. The validity of a diffusion-controlled model for non-mixing growth conditions is particularly noted.

  15. Surface photovoltage spectroscopy analyses of Cd{sub 1-x}Zn{sub x}Te

    SciTech Connect

    Cavalcoli, D.; Fraboni, B.; Cavallini, A.

    2008-02-15

    Cd{sub 1-x}Zn{sub x}Te alloys have been studied by surface photovoltage spectroscopy (SPS) and energy dispersive spectroscopy (EDS). The analyses of surface photovoltage spectra have been perfomed at near and above band gap energies. Surface recombination effects on the surface photovoltage have been investigated. SPS analyses of Cd{sub 1-x}Zn{sub x}Te alloys with different surface conditions have shown that the surface recombination velocity significantly affects the SPS determination of the material band gap. Accounting for this and preparing the surfaces accordingly, SPS spectra of Cd{sub 1-x}Zn{sub x}Te samples have allowed an accurate determination of the optical band gap as a function of the Zn concentration, determined via EDS analyses. The local increases in the density of states associated with band structure features in Cd{sub 1-x}Zn{sub x}Te alloys have been investigated by SPS spectra in the above band gap energy range.

  16. XTE J1752-223: Optical spectroscopy and infrared counterpart detection

    NASA Astrophysics Data System (ADS)

    Torres, M. A. P.; Steeghs, D.; Jonker, P. G.; Thompson, I.; Soderberg, A. M.

    2009-10-01

    Prompted by the discovery of its bright optical counterpart and the announcement of increased X-ray activity (ATels #2258, #2259, #2261, #2265, #2263), we have acquired additional observations of XTE J1752-223 at optical and near-infrared wavelengths. OPTICAL SPECTROSCOPY: An optical spectrum covering 3330-9165 Angstrom was obtained with the MIKE echelle spectrograph on the Magellan Clay telescope starting on 2009 Oct 26 UT 23:52.

  17. Development of the solar array deployment and drive system for the XTE spacecraft

    NASA Technical Reports Server (NTRS)

    Farley, Rodger; Ngo, Son

    1995-01-01

    The X-ray Timing Explorer (XTE) spacecraft is a NASA science low-earth orbit explorer-class satellite to be launched in 1995, and is an in-house Goddard Space Flight Center (GSFC) project. It has two deployable aluminum honeycomb solar array wings with each wing being articulated by a single axis solar array drive assembly. This paper will address the design, the qualification testing, and the development problems as they surfaced of the Solar Array Deployment and Drive System.

  18. Discovery of Radio Emission From Transient Anomalous X-Ray Pulsar XTE J1810-197

    SciTech Connect

    Halpern, J P; Gotthelf, E V; Becker, R H; Helfand, D J; White, R L

    2005-10-25

    We report the first detection of radio emission from any anomalous X-ray pulsar (AXP). Data from the Very Large Array (VLA) MAGPIS survey with angular resolution 6'' reveals a point-source of flux density 4.5 {+-} 0.5 mJy at 1.4 GHz at the precise location of the 5.54 s pulsar XTE J1810-197. This is greater than upper limits from all other AXPs and from quiescent states of soft gamma-ray repeaters (SGRs). The detection was made in 2004 January, 1 year after the discovery of XTE J1810-197 during its only known outburst. Additional VLA observations both before and after the outburst yield only upper limits that are comparable to or larger than the single detection, neither supporting nor ruling out a decaying radio afterglow related to the X-ray turn-on. Another hypothesis is that, unlike the other AXPs and SGRs, XTE J1810-197 may power a radio synchrotron nebula by the interaction of its particle wind with a moderately dense environment that was not evacuated by previous activity from this least luminous, in X-rays, of the known magnetars.

  19. Revealing Evidence of Spin in Galactic Black Holes

    NASA Astrophysics Data System (ADS)

    Miller, J. M.; Fabian, A. C.; Reynolds, C. S.; Nowak, M.; Wijnands, R.; Homan, J.; Belloni, T.; van der Klis, M.; Lewin, W. H. G.

    2002-12-01

    Our observations of Galactic black holes with Chandra and XMM-Newton have recently revealed broad, skewed Fe K-alpha emission lines similar to those seen in some AGN. If such lines are produced near the inner edge of the accretion disk, they can serve as an excellent spin diagnostic. Our analysis of the XMM-Newton spectrum of XTE J1650-500 reveals a strong, skewed Fe K-alpha emission line that requires near-maximal spin; with RXTE, we have discovered a 250 Hz QPO in this source which may also be produced near to the black hole. Although many Galactic black holes have been studied extensively, it is extremely rare that spectroscopic and timing studies both reveal features plausibly associated with the inner accretion disk. We will present the results of our XMM-Newton, Chandra, and RXTE observations of XTE J1650-500, as well as the results of our Chandra observations of Cygnus X-1 and preliminary results from our observations of GX 339-4 with XMM-Newton. We will discuss these results within the context of the relativistic Fe K lines reported by our group and others, and comment on the prospects for revealing evidence of spin in future observations. (JMM acknowledges support from the NSF through the Astronomy and Astrophysics Fellowship program.)

  20. Serendipitous Detections of XTE J1906+09 with the Rossi X-Ray Timing Explorer

    NASA Technical Reports Server (NTRS)

    Wilson, Colleen A.; Finger, Mark H.; Gogus, Ersin; Woods, Peter M.; Kouveliotou, Chryssa

    2002-01-01

    The 89 s X-ray pulsar XTE J1906+09 was discovered during Rossi X-Ray Timing Explorer (RXTE) observations of SGR 1900+14 in 1996. Because of monitoring campaigns of SGR 1900+14, XTE J1906+09 was also monitored regularly in 1996 September, 1998 May-June, 1998 August-1999 July, and 2000 March-2001 January. A search for pulsations resulted in detections of only the two previously reported outbursts in 1996 September and 1998 August-September. Pulsed flux upper limits for the rest of the observations show that XTE J1906+09 is a transient X-ray pulsar and likely has a Be star companion. The RXTE all-sky monitor did not reveal XTE J1906+09. Pulse-timing analysis of the second outburst discovered a sinusoidal signature in the pulse frequencies that is likely produced by an orbital periastron passage. Fits to pulse phases using an orbital model and quadratic phase model have chi(exp 2) minima at orbital periods of 26-30 days for fixed mass functions of 5, 10, 15, and 20 solar masses. The pulse shape showed energy- and intensity-dependent variations. Pulse-phase spectroscopy quantified the energy-dependent variations. The phase-averaged spectrum used the pulse minimum spectrum as the background spectrum to eliminate effects from SGR 1900+14 and the Galactic ridge and was well fitted by an absorbed power law with a high-energy cutoff with column density N(sub H) = 6 +/- 1 x 10(exp 22)/sq cm, a photon index of 1.01 +/- 0.08, cutoff energy E(sub cut) = 11 +/- 1 keV, and e-folding energy E(sub fold) = 19 +/- 4 keV. Estimated 2-10 keV peak fluxes, corrected for contributions from the Galactic ridge and SGR 1900+14, are 6 x l0(exp -12) and 1.1 x 10(exp -10) ergs/sq cm/s for the 1996 and 1998 outbursts, respectively. XTE J1906+09 may be part of an unusual class of Be/X-ray binaries that do not lie on the general spin period versus orbital period correlation with the majority of Be/X-ray binaries.

  1. Near-infrared and optical observations of the failed outbursts of black hole binary XTE J1550-564

    NASA Astrophysics Data System (ADS)

    Curran, P. A.; Chaty, S.

    2013-09-01

    Context. A number of low mass X-ray binaries (LMXBs) undergo "failed outbursts" in which, instead of evolving through the canonical states, they remain in a hard state throughout the outburst. While the sources of X-ray and radio emission in the hard state are relatively well understood, the origin of the near-infrared (NIR) and optical emission is more complex though it likely stems from an amalgam of different emission processes, occurring as it does, at the intersecting wavelengths of those processes. Aims: We aim to identify the NIR/optical emission region(s) during a number of failed outbursts of one such LMXB and black hole candidate, XTE J1550-564, in order to confirm or refute their classification as hard-state, failed outbursts. Methods: We present unique NIR/optical images and spectra, obtained with the ESO-New Technology Telescope, during the failed outbursts of 2001 and 2000. We compare the NIR/optical photometric, timing, and spectral properties with those expected for the different emission mechanisms in the various LMXB states. Results: The NIR/optical data are consistent with having come from reprocessing of X-rays in the accretion disk, with no evidence of direct thermal emission from the disk itself. However, the observed variability in high-cadence NIR light curves suggest that the radio jet extends and contributes to the NIR wavelengths. Conclusions: We find that these failed outbursts did not transition to an intermediate state but remained in a true, hard state where there was no sign of jet quenching or deviation from the observed hard state correlations. Based on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.

  2. The Accretion Rate Independence of Horizontal Branch Oscillation in XTE J1701-462

    NASA Astrophysics Data System (ADS)

    Li, Zhaosheng; Chen, Li; Qu, Jinlu; Bu, Qingcui; Wang, Dehua; Xu, Renxin

    2014-05-01

    We study the temporal and energy spectral properties of the unique neutron star low-mass X-ray binary XTE J1701-462. Assuming the horizontal branch/normal branch (HB/NB) vertex as a reference position of the accretion rate, the horizontal branch oscillation (HBO) of the HB/NB vertex is roughly 50 Hz. It indicates that the HBO is independent of the accretion rate or the source intensity. The spectral analysis shows R_{in}\\propto \\dot{M}_{Disk}^{2.9+/- 0.09} in the HB/NB vertex and R_{in}\\propto \\dot{M}_{Disk}^{1.7+/- 0.06} in the NB/flaring branch (FB) vertex, which implies that different accretion rates may be produced in the HB/NB and NB/FB vertex. The Comptonization component could be fitted by a constrained broken power law or nthComp. Unlike GX 17+2, the frequencies of HBO positively correlate with the inner disk radius, which contradict with the prediction of the Lense-Thirring precession model. XTE J1701-462, both in the Cyg-like phase and in the Sco-like phase, follows a positive correlation between the break frequency of broadband noise and the characteristic frequency of HBO, which is called the W-K relation. An anticorrelation between the frequency of HBO and photon energy is observed. Moreover, the rms of HBO increases with photon energy until ~10 keV. We discuss the possible origin of HBO from the corona in XTE J1701-462.

  3. Serendipitous Detections of XTE J1906+09 with the Rossi X-ray Timing Explorer

    NASA Technical Reports Server (NTRS)

    Wilson, Colleen A.; Finger, Mark H.; Gogus, Ersin; Woods, Peter M.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    In 1996 during Rossi X-ray Timing Explorer (RXTE) observations of SCR 1900+14, the 89-second X-ray pulsar XTE J1906+09 was discovered. As a result of monitoring campaigns of SGR 1900+14, XTE J1906+09 was also monitored regularly in 1996 September, 1998 May-June, 1998 August-1999 July, and 2000 March-2001 January. A frequency grid search of these observations resulted in detections of only the two previously reported outbursts in 1996 September and 1998 August-September. The non-detection of XTE J1906+09 in most observations indicates that it is a transient X-ray pulsar and therefore likely has a Be star companion, Pulse timing analysis of the second outburst revealed a sinusoidal signature in the pulse frequencies that is likely produced by periastron passage in a long period, eccentric, orbit. During the second outburst, the pulse shape changed with increasing intensity, Low intensity pulse profiles from the second outburst are consistent with profiles from the fainter first outburst. Energy dependent pulse shape variations were seen in both outbursts. Pulse phase spectroscopy was used to quantify these variations. The phase averaged spectrum, using the pulse minimum spectrum as the background spectrum to eliminate effects from SGR 1900+14 and the galactic ridge, was well fitted by an absorbed power law with a high energy cutoff with column density N(sub H) = (6 +/- 1) x 10(exp 22) cm(sup -2), photon index = 1.01 +/- 0.08, cutoff energy E(sub cut) = 11 +/- 1 keV, and folding energy E(sub fold) = 19 +/- 4 keV.

  4. An XTE Observation of the VELA Pulsar and Inner Region of the VELA SNR

    NASA Astrophysics Data System (ADS)

    Strickman, Mark

    Using three XTE pointing fields in the inner region of the Vela Supernova Remnant, we propose to answer three fundamental questions concerning this most interesting object: 1) What is the spectrum of the Vela Pulsar between 1 keV (ROSAT) and 60 keV (OSSE)? If a cutoff is detected, it may constitute a measurement of the pulsar magnetic field in the production region. 2) Does unpulsed emission recently detected by OSSE actually come from the compact nebula surrounding the pulsar? 3) Is the asymmetry of emission NE and SW of the pulsar as viewed by ROSAT and EINSTEIN reflected at higher energies?

  5. Corrected Name for 5.54 s Pulsar: XTE J1810-197

    NASA Astrophysics Data System (ADS)

    Swank, J. H.; Markwardt, C. B.; Ibrahim, A. I.

    2003-07-01

    In ATEL 167, we reported the position of a new source as R.A. = 18h10.9m, Decl. = -19o42' (equinox 2000.0) , with estimated 99% confidence semi-major axes of 5' in R.A. and 7' in Decl. We designated the new pulsar as XTE J1811-197. The same name appeared in CBET 36. It was brought to our attention by Dr. Marion Schmitz, head of the IAU Working Group on Designations, that the name did not follow the specifications of the IAU, which can be found at: http://cdsweb.u-strasbg.fr/iau-spec.html.

  6. Magnetoreflectivity of Pb{sub 1{minus}x}Eu{sub x}Te epilayers and PbTe/Pb{sub 1{minus}x}Eu{sub x}Te multiple quantum wells

    SciTech Connect

    Yuan, S.; Krenn, H.; Springholz, G.; Ueta, Y.; Bauer, G.; McCann, P.J.

    1997-02-01

    Molecular-beam epitaxy grown n-type Pb{sub 1{minus}x}Eu{sub x}Te epilayers (x{le}0.034) and PbTe/Pb{sub 1{minus}x}Eu{sub x}Te (x{le}0.039) multiple-quantum-well (MQW) samples were studied by magnetoreflectivity in the Faraday configuration (B{parallel}[111]) for magnetic fields up to 6T at 4.2 K. Since the IV-VI lead salt compounds are quite polar semiconductors, resonant electron-longitudinal-optic- (LO-) phonon coupling (Fr{umlt o}hlich coupling) modifies the cyclotron resonance (CR) energies in the Pb{sub 1{minus}x}Eu{sub x}Te single epilayers for the three-dimensional (3D) case. Due to the many-valley band structure {ital two} different Fr{umlt o}hlich coupling constants are relevant. However, the CR energies of quasi-two-dimensional (2D) carriers in PbTe wells [n{sup 2D}=(1.5{minus}3){times}10{sup 11}cm{sup {minus}2}] of PbTe/Pb{sub 1{minus}x}Eu{sub x}Te MQW samples do {ital not} exhibit a significant resonant electron-LO-phonon interaction. This observation is attributed to finite-electron concentration effects, in particular, to a partial filling of the lowest 2D Landau spin level. The static and dynamic screening of the polar interaction are considered as well, but are ruled out as an explanation for the absence of any remarkable polaron correction to the CR energies of electrons in the PbTe quantum wells for the range of carrier concentrations investigated. The magnetoreflectivity spectra of Pb{sub 1{minus}x}Eu{sub x}Te single layers and PbTe/Pb{sub 1{minus}x}Eu{sub x}Te quantum well samples are simulated numerically, using a model for the dielectric response of which also includes the electron-LO-phonon interaction. The transverse and longitudinal masses, and thus also the interband momentum matrix elements are determined for Pb{sub 1{minus}x}Eu{sub x}Te as a function of the composition up to x{lt}0.034. It is found that the transverse mass {ital increases} with Eu content, whereas the longitudinal one nearly stays constant. (Abstract Truncated)

  7. Growth and magnetic properties of IV-VI diluted magnetic semiconductor Ge{sub 1-x}Cr{sub x}Te

    SciTech Connect

    Fukuma, Y.; Taya, T.; Miyawaki, S.; Irisa, T.; Asada, H.; Koyanagi, T.

    2006-04-15

    IV-VI diluted magnetic semiconductor Ge{sub 1-x}Cr{sub x}Te films were grown on BaF{sub 2} substrates by molecular-beam epitaxy. The Ge{sub 1-x}Cr{sub x}Te film up to x=0.103 is single phase as determined by reflection high-energy electron diffraction and x-ray diffraction measurements. The optical band gap decreases with increasing Cr composition. Ferromagnetic order of the Ge{sub 1-x}Cr{sub x}Te films is characterized by direct magnetization and anomalous Hall effect measurements.

  8. Doppler tomography of the X-ray nova XTE J1118+480 in outburst and near quiescence

    NASA Astrophysics Data System (ADS)

    Torres, M. A. P.; Callanan, P. J.; Garcia, M. R.

    2002-01-01

    We present Doppler images of the more intense emission lines in the spectrum of the Black Hole X-ray Nova XTE J1118+480 during the 2000 outburst and near quiescence. Use of MOLLY, DOPPLER and TRAILER routines developed largely by T. R. Marsh is acknowledged.

  9. INTEGRAL Long-Term Monitoring of the Supergiant Fast X-Ray Transient XTE J1739-302

    NASA Technical Reports Server (NTRS)

    Blay, P.; Martinez-Nunez, S.; Negueruela, I.; Pottschmidt, K.; Smith, D. M.; Torrejon, J. M.; Reig, P.; Kretschmar, P.; Kreykenbohm, I.

    2008-01-01

    Context. In the past few years, a new class of High Mass X-Ray Binaries (HMXRB) has been claimed to exist, the Supergiant Fast X-ray Transients (SFXT). These are X-ray binary systems with a compact companion orbiting a supergiant star which show very short and bright outbursts in a series of activity periods overimposed on longer quiescent periods. Only very recently the first attempts to model the behaviour of these sources have been published, some of them within the framework of accretion from clumpy stellar winds. Aims. Our goal is to analyze the properties of XTE J1739-302/IGR J17391-3021 within the context of the clumpy structure of the supergiant wind. Methods. We have used INTEGRAL and RXTE/PCA observations in order to obtain broad band (1 - 200 keV) spectra and light curves of XTE J1739-302 and investigate its X-ray spectrum and temporal variability. Results. We have found that XTE J1739-302 follows a much more complex behaviour than expected. Far from presenting a regular variability pattern, XTE J1739-302 shows periods of high, intermediate, and low flaring activity.

  10. Discovery of a Second Millesecond Accreting Pulsar: XTE J1751-305

    NASA Technical Reports Server (NTRS)

    Markwardt, C. B.; Swank, J. H.; Strohmayer, T. E.; intZand, J. J. M.; Marshall, F. E.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We report the discovery by the RXTE PCA of a second transient accreting millisecond pulsar, XTE J1751-305, during regular monitoring observations of the galactic bulge region. The pulsar has a spin frequency of 435 Hz, making it one of the fastest pulsars. The pulsations contain the signature of orbital Doppler modulation, which implies an orbital period of 42 minutes, the shortest orbital period of any known radio or X-ray millisecond pulsar. The mass function, f(sub x) = (1.278 +/- 0.003) x 10 (exp -6) solar mass, yields a minimum mass for the companion of between 0.013 and 0.0017 solar mass depending on the mass of the neutron star. No eclipses were detected. A previous X-ray outburst in June, 1998, was discovered in archival All-Sky Monitor data. Assuming mass transfer in this binary system is driven by gravitational radiation, we constrain the orbital inclination to be in the range 30 deg-85 deg and the companion mass to be 0.013-0.035 solar mass. The companion is most likely a heated helium dwarf. We also present results from the Chandra HRC-S observations which provide the best known position of XTE J1751-305.

  11. The variable spin-down rate of the transient magnetar XTE J1810-197

    NASA Astrophysics Data System (ADS)

    Pintore, Fabio; Bernardini, Federico; Mereghetti, Sandro; Esposito, Paolo; Turolla, Roberto; Rea, Nanda; Coti Zelati, Francesco; Israel, Gian Luca; Tiengo, Andrea; Zane, Silvia

    2016-05-01

    We have analysed XMM-Newton and Chandra observations of the transient magnetar XTE J1810-197 spanning more than 11 yr, from the initial phases of the 2003 outburst to the current quiescent level. We investigated the evolution of the pulsar spin period and we found evidence for two distinct regimes: during the outburst decay, dot{ν } was highly variable in the range -(2-4.5) × 10-13 Hz s-1, while during quiescence the spin-down rate was more stable at an average value of -1 × 10-13 Hz s-1. Only during ˜3000 d (from MJD 54165 to MJD 56908) in the quiescent stage it was possible to find a phase-connected timing solution, with dot{ν }=-4.9× 10^{-14} Hz s-1, and a positive second frequency derivative, ddot{ν }=1.8× 10^{-22} Hz s-2. These results are in agreement with the behaviour expected if the outburst of XTE J1810-197 was due to a strong magnetospheric twist.

  12. Looking into the Theory of Pulsar Accretion: The Case of XTE J1946+274

    NASA Astrophysics Data System (ADS)

    Marcu, Diana Monica; Pottschmidt, Katja; Kühnel, Matthias; Wolff, Michael Thomas; Becker, Peter A.; Müller, Sebastian; Hemphill, Paul Britton; Caballero, Isabel; Finger, Mark H.; Jenke, Peter; Wilson-Hodge, Colleen; Fuerst, Felix; Grinberg, Victoria; Kreykenbohm, Ingo; Klochkov, Dmitry; Rothschild, Richard E.; Terada, Yukikatsu; Enoto, Teruaki; Iwakiri, Wataru; Nakajima, Motoki; Wilms, Joern

    2014-08-01

    XTE J1946+274 is a transient accreting pulsar with a Be companion and a Cyclotron Resonance Scattering Feature (CRSF). It has been observed during several outbursts, with multiple instruments, and over a large range of luminosities. We extend previous studies to low flux using a Suzaku observation from the end of an outburst. This study focuses on the relationship between the cyclotron line energy and X-ray luminosity, which is believed to be linked to the physical processes occurring in the CRSF forming region. The physics of pulsar accretion, i.e., the process of plasma flow onto the neutron star surface, can be further constrained from its spectral properties. To this end, we discuss a new implementation of the physical continuum model developed by Becker and Wolff (2007, ApJ 654, 435). The model comprises Comptonized black body, bremsstrahlung, and cyclotron emission. We discuss preliminary results of applying the new tool to the test case of XTE J1946+274. We are working towards making this pulsar continuum model available in Xspec.

  13. Phonon Density of States and Heat Capacity of La$_{3-x}$Te$_4$

    SciTech Connect

    Delaire, Olivier A; May, Andrew F.; McGuire, Michael A; Porter, Wallace D; Lucas,; Stone, Matthew B; Abernathy, Douglas L; Snyder, G. J.

    2009-01-01

    The phonon density of states (DOS) of La$_{3-x}$Te$_4$ compounds ($x=0.0, 0.18, 0.32$) was measured at 300, 520, and 780$\\,$K, using inelastic neutron scattering. A significant stiffening of the phonon DOS, and a large broadening of features were observed upon introduction of vacancies on La sites (increasing $x$). Heat capacity measurements were performed at temperatures $~1.85 \\leqslant T \\leqslant 1200 \\,$K, and were analyzed to quantify the contributions of phonons and electrons. The Debye temperature and the electronic coefficient of heat capacity determined from these measurements are consistent with the neutron scattering results, and with previously reported first-principles calculations. Our results indicate that La vacancies in La$_{3-x}$Te$_4$ strongly scatter phonons, and this source of scattering appears to be independent of temperature. The stiffening of the phonon DOS induced by the introduction of vacancies is explained in terms of the electronic structure and the change in bonding. The temperature dependence of the phonon DOS is captured satisfactorily by the quasiharmonic approximation.

  14. The Reawakening of the Sleeping X-ray Pulsar XTE J1946+274

    NASA Technical Reports Server (NTRS)

    Mueller, Sebastian; Mueller, Sebastian; Kuechnel, Matthias; Fuerst, Felix; Kreykenbohm, Ingo; Sagredo, Macarena; Obst, Maria; Wilms, Joern; Caballero, Isabel; Potttschmidt, Katja; Ferrigno, Carlo; Rothschild, Richard E.

    2012-01-01

    We report on a series of outbursts of the high mass X-ray binary XTE 11946+274 in 2010/2011 as observed with INTEGRAL, RXTE, and Swift. We discuss possible mechanisms resulting in the extraordinary outburst behavior of this source. The X-ray spectra can be described by standard phenomenological models, enhanced by an absorption feature of unknown origin at about 10 keV and a narrow iron K alpha fluorescence line at 6.4keV, which are variable in flux and pulse phase. We find possible evidence for the presence of a cyclotron resonance scattering feature at about 25 keV at the 93% level. The presence of a strong cyclotron line at 35 keV seen in data from the source's 1998 outburst and confirmed by a reanalysis of these data can be excluded. This result indicates that the cyclotron line feature in XTE 11946+274 is variable between individual outbursts.

  15. Doppler tomography of XTE J1118+480 revealing chromospheric emission from the secondary star

    NASA Astrophysics Data System (ADS)

    Zurita, C.; González Hernández, J. I.; Escorza, A.; Casares, J.

    2016-08-01

    Doppler tomography of emission lines in low-mass X-ray binaries allows us to investigate the structure and variability of the accretion discs as well as possible activity arising from the secondary stars. We present Doppler maps of the black hole binary XTE J1118+480 from spectra obtained using OSIRIS@GTC during quiescence on four different nights in 2011 and 2012. Doppler imaging of the Hα line shows, for the first time, a narrow component from the secondary star with observed equivalent widths varying in the range 1.2-2.9 Å but not correlated with the veiling of the accretion disc. The Hα flux of the secondary star is too large to be powered by X-ray irradiation, supporting chromospheric activity, possibly induced by rapid rotation, as the most likely origin of this feature in the black hole X-ray binary XTE J1118+480. In addition, we detect variations in the centroid of the Hα line on nightly basis. These are likely caused by a precessing accretion disc, although with a much lower amplitude (˜50 km s-1) than previously observed.

  16. Relativistic Iron Emission and Disk Reflection in Galactic Microquasar XTE J1748-288

    NASA Technical Reports Server (NTRS)

    Miller, J. M.; Fox, D. W.; DiMatteo, T.; Wijnands, R.; Belloni, T.; Pooley, D.; Kouveliotou, C.; Lewin, W. H. G.

    2001-01-01

    We report evidence for an Fe K-alpha fluorescence line feature and disk reflection in the very high, high-, and low-state X-ray spectra of the Galactic microquasar XTE J1748 - 288 during its 1998 June outburst. Spectral analyses are made on data gathered throughout the outburst by the Rossi X-Ray Timing Explorer Proportional Counter Array. Gaussian line, relativistic disk emission line, and ionized disk reflection models are fitted to the data. In the very high state the line profile appears strongly redshifted, consistent with disk emission from the innermost stable orbits around a maximally rotating Kerr black hole. In the high state the line profile is less redshifted and increasingly prominent. The low-state line profile is very strong (approx. 0.5 keV equivalent width) and centered at 6.7 +/- 0.10 keV; disk line emission model fits indicate that the inner edge of the disk fluctuates between approx. 20R(sub g) and - approx. 100R(sub g) in this state. The disk reflection fraction is traced through the outburst; reflection from an ionized disk is preferred in the very high and high states, and reflection from a relatively neutral disk is preferred in the low state. We discuss the implications of our findings for the binary system dynamics and accretion flow geometry in XTE J1748 - 288.

  17. Relativistic Iron Emission and Disk Reflection in Galactic Microquasar XTE J1748-288

    NASA Technical Reports Server (NTRS)

    Miller, J. M.; Fox, D. W.; Matteo, T. DI; Wijnands, R.; Belloni, T.; Pooley, D.; Kouveliotou, C.; Lewin, W. H. G.

    2001-01-01

    We report evidence for an Fe K(alpha) fluorescence line feature and disk reflection in the very high, high-, and low-state X-ray spectra of the Galactic microquasar XTE J1748-288 during its 1998 June outburst. Spectral analyses are made on data gathered throughout the outburst by the Rossi X-Ray Timing Explorer Proportional Counter Array. Gaussian line, relativistic disk emission line, and ionized disk reflection models are fitted to the data. In the very high state the line profile appears strongly redshifted, consistent with disk emission from the innermost stable orbits around a maximally rotating Kerr black hole. In the high state the line profile is less redshifted and increasingly prominent. The low-state line profile is very strong (approx. 0.5 keV equivalent width) and centered at 6.7 +/- 0.10 keV; disk line emission model fits indicate that the inner edge of the disk fluctuates between approx. 20Rg and approx. 100Rg in this state. The disk reflection fraction is traced through the outburst; reflection from an ionized disk is preferred in the very high and high states, and reflection from a relatively neutral disk is preferred in the low state. We discuss the implications of our findings for the binary system dynamics and accretion flow geometry in XTE J1748-288.

  18. Doppler tomography of XTE J1118+480 revealing chromospheric emission from the secondary star

    NASA Astrophysics Data System (ADS)

    Zurita, C.; González Hernández, J. I.; Escorza, A.; Casares, J.

    2016-05-01

    Doppler tomography of emission lines in low-mass X-ray binaries allows us to investigate the structure and variability of the accretion disks as well as possible activity arising from the secondary stars. We present Doppler maps of the black hole binary XTE J1118+480 from spectra obtained using OSIRIS@GTC during quiescence on four different nights in 2011 and 2012. Doppler imaging of the Hα line shows, for the first time, a narrow component from the secondary star with observed equivalent widths varying in the range 1.2-2.9 Å but not correlated with the veiling of the accretion disc. The Hα flux of the secondary star is too large to be powered by X-ray irradiation, supporting chromospheric activity, possibly induced by rapid rotation, as the most likely origin of this feature in the black hole X-ray binary XTE J1118+480. In addition, we detect variations in the centroid of the Hα line on nightly basis. These are likely caused by a precessing accretion disc, although with a much lower amplitude (˜50 km/s) than previously observed.

  19. Black Hole X Ray Nova Outburst with XTE and HST

    NASA Technical Reports Server (NTRS)

    Patterson, Joseph; Haswell, Carole

    1998-01-01

    We obtained multiwavelength coverage of the soft X-ray transient. GRO J1655-40 during its 1996 outburst, using HST (Hubble Space Telescope), RXTE (Rossi X Ray Timing Explorer), CGRO (Compton Gamma Ray Observatory), and ground-based facilities. This outburst was qualitatively different from other SXT (Soft X Ray Telescope) outbursts and from previous outbursts of this source. The onset of hard X-ray activity occurred very slowly, over several months, and was delayed relative to the soft X-ray rise. During this period, the optical fluxes declined steadily. This apparent anticorrelation is not consistent with with the standard disk instability model of SXT outbursts, nor is it expected if the optical output is dominated by reprocessed X-rays, as in persistent low-mass X-ray binaries. Based on the strength of the 2175-A interstellar absorption feature, we constrain the reddening to be E(B - V) = 1.2 plus or minus 0.1, a result which is consistent with the known properties of the source and with the strength of other interstellar absorption lines. After this dereddening we find that the spectra are dominated by a component peaking in the optical, with the expected v (sup l/3) disk spectrum seen only in the ultraviolet. Bowen fluorescence lines of NIII and OIII are also seen, as well as possible P Cyg profiles in the ultraviolet resonance lines. These features suggest an accretion-disk wind. The X-ray spectra broadly resemble the high/soft state commonly seen in black hole candidates, but evolve through two substates.

  20. Correlations in Horizontal Branch Oscillations and Break Components in XTE J1701-462 and GX 17+2

    NASA Astrophysics Data System (ADS)

    Bu, Qing-cui; Chen, Li; Li, Zhao-sheng; Qu, Jin-lu; Belloni, T. M.; Zhang, Liang

    2015-01-01

    We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent "Sco-like" Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources, and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundary that separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, though it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studied the correlation between rms at the break and the HBO frequency. We suggest that HBO and break components for both sources probably arise from a similar physical mechanism: Comptonization emission from the corona. These two components could be caused by the same kind of oscillation in a corona with uneven density, and they could be generated from different areas of the corona. We further suggest that different proportions of the Comptonization component in the total flux cause the different distribution between GX 17+2 and XTE J1701-462 in the rmsbreak-rmsHBO diagram.

  1. CORRELATIONS IN HORIZONTAL BRANCH OSCILLATIONS AND BREAK COMPONENTS IN XTE J1701-462 AND GX 17+2

    SciTech Connect

    Bu, Qing-cui; Chen, Li; Zhang, Liang; Li, Zhao-sheng; Qu, Jin-lu; Belloni, T. M. E-mail: chenli@bnu.edu.cn E-mail: tomaso.belloni@brera.inaf.it

    2015-01-20

    We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent ''Sco-like'' Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources, and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundary that separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, though it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studied the correlation between rms at the break and the HBO frequency. We suggest that HBO and break components for both sources probably arise from a similar physical mechanism: Comptonization emission from the corona. These two components could be caused by the same kind of oscillation in a corona with uneven density, and they could be generated from different areas of the corona. We further suggest that different proportions of the Comptonization component in the total flux cause the different distribution between GX 17+2 and XTE J1701-462 in the rms{sub break}-rms{sub HBO} diagram.

  2. Accretion flow behaviour during the evolution of the quasi-periodic oscillation frequency of XTE J1550-564 in 1998 outburst

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Sandip K.; Dutta, Broja G.; Pal, P. S.

    2009-04-01

    Low and intermediate frequency quasi-periodic oscillations (QPOs) are thought to be due to oscillations of Comptonizing regions or hot regions embedded in Keplerian discs. Observational evidence of evolutions of QPOs would therefore be very important as they throw lights on the dynamics of the hotter region. Our aim is to find systems in which there is a well-defined correlation among the frequencies of the QPOs over a range of time so as to understand the physical picture. In this paper, we concentrate on the archival data of XTE J1550-564 obtained during 1998 outburst, and study the systematic drifts during the rising phase from the 1998 September 7 to the 1998 September 19, when the QPO frequency increased monotonically from 81mHz to 13.1Hz. Immediately after that, QPO frequency started to decrease and on the 1998 September 26, the QPO frequency became 2.62Hz. After that, its value remained almost constant. This frequency drift can be modelled satisfactorily with a propagatory oscillating shock solution where the post-shock region behaves as the Comptonized region. Comparing with the nature of a more recent 2005 outburst of another black hole candidate GRO 1655-40, where QPOs disappeared at the end of the rising phase, we conjecture that this so-called `outburst' may not be a full-fledged outburst.

  3. Tuning the composition of ternary Bi2Se3xTe3(1-x) nanoplates and their Raman scattering investigations

    NASA Astrophysics Data System (ADS)

    Wu, Peng; Chen, Haiping; Yang, Chao; Gan, Wei; Muhammad, Zahir; Song, Li

    2016-07-01

    We present the composition engineering and Raman scattering study of Bi2Se3xTe3(1-x) nanoplates that were synthesized by chemical vapor deposition method using different substrates, including fluorophlogopite mica, SiO2/Si. The characterizations revealed high crystallinity and layered-structure in the ternary Bi2Se3xTe3(1-x) products. Raman spectra of Bi2Se3xTe3(1-x) ranging from 80-200 cm-1 as a function of different Se-doping levels shows that intrinsic Raman peaks of Bi2Se3xTe3(1-x) nanoplates shift to higher frequency as the ratio of doped-Se increasing. The discontinuity of Raman peaks was found and discussed.

  4. Analysis of Cd{sub 1{minus}x}Zn{sub x}Te microstructure

    SciTech Connect

    Heffelfinger, J.R.; Medlin, D.L.; Yoon, H.; James, R.B.

    1997-08-01

    The microstructure and chemical inhomogeneities of commercially available Cd{sub 1{minus}x}Zn{sub x}Te (CZT) have been evaluated using electron microscopy and microanalytical techniques. Since imperfections, such as inclusions, cracks and extended crystallographic defects are known to affect the performance of CZT gamma-ray spectrometers, understanding the nature and origins of such imperfections is vital to the improvement of device performance. CZT that is grown using a high-pressure Bridgeman method has a polycrystalline microstructure that contains numerous grain boundaries, twins and inclusions. In this study, scanning electron microscopy and X-ray energy-dispersive spectroscopy were used to analyze inclusions and cracks inside CZT material. Such analysis found regions of material rich in C, O, Si, Zn and Te. Transmission electron microscopy revealed small subgrains and thin platelets of a second phase material located inside the large-grain CZT matrix. Details of these microstructural features and their possible origins are discussed.

  5. Gamma-ray polarization in accreting black holes: the case of XTE J1118+480

    NASA Astrophysics Data System (ADS)

    Vieyro, Florencia; Chaty, Sylvain; Romero, Gustavo E.

    2016-07-01

    Several black hole binaries (BHBs) present persistent soft gamma-ray emission (up to E ˜MeV). Although different models have been proposed to explain the origin of this component (non-thermal corona, relativistic jets), its nature still remains unknown. The detection of strong polarization at high-energies in the well-studied system Cygnus X-1 provides new constraints on the emitting region of the radiation. In this work we study the case of the BHB XTE J1118+480, a transient source that has been observed during two outbursts. In both cases multiwavelenght observations could be obtained because of the privileged location of the source, which implies low interstellar absorption. We apply a non-thermal lepto-hadronic coronal model to reproduce the X/γ-ray emission of this BHB during its outburts, and study the polarization of high-energy radiation expected for future episodes.

  6. SUBARCSECOND LOCATION OF IGR J17480-2446 WITH ROSSI XTE

    SciTech Connect

    Riggio, A.; Burderi, L.; Egron, E.; Di Salvo, T.; D'Ai, A.; Iaria, R.; Robba, N. R.; Papitto, A.; Belloni, T.; Motta, S.; Floris, M.; Testa, V.; Menna, M. T.

    2012-07-20

    On 2010 October 13, the X-ray astronomical satellite Rossi XTE, during the observation of the newly discovered accretion powered X-ray pulsar IGR J17480-2446, detected a lunar occultation of the source. From knowledge of the lunar topography and Earth, Moon, and spacecraft ephemerides at the epoch of the event, we determined the source position with an accuracy of 40 mas (1{sigma} c.l.), which is interesting, given the very poor imaging capabilities of RXTE ({approx}1 Degree-Sign ). For the first time, using a non-imaging X-ray observatory, the position of an X-ray source with a subarcsecond accuracy is derived, demonstrating the neat capabilities of a technique that can be fruitfully applied to current and future X-ray missions.

  7. A versatile 50 ft-lb-sec reaction wheel for TRMM and XTE missions

    NASA Astrophysics Data System (ADS)

    Bialke, Bill

    A 50 ft-lb-sec Reaction Wheel is being manufactured by ITHACO, Inc. for NASA's X-ray Timing Explorer (XTE) and Tropical Rainfall Measuring Mission (TRMM) missions, using the same mechanical assemblies as a similar Reaction Wheel developed by ITHACO for the Air Force's Advanced Research and Global Observation Satellite (ARGOS) (P91-1) mission. The versatile design allows variation in motor torque and speed capability with no mechanical modifications. State of the art ball bearing technology is combined with flight proven materials and conventional fabrication techniques to produce a relaible and manufacturable wheel assembly. An ironless armature brushless DC motor is incorporated for high efficiency and minimum weight. Comprehensive tradeoff analyses from the Reaction Wheel development are discussed for each component, and performance characteristics are presented for design variations from a high torque Reaction Wheel used in a three axis stabilized spacecraft to a low torque Momentum Wheel used in a momentum biased attitude Control System.

  8. Joint BeppoSAX/RossiXTE Observation of Cygnus X-2

    NASA Astrophysics Data System (ADS)

    Piraino, S.; Santangelo, A.; Kaaret, P.

    2001-09-01

    We report on a joint BeppoSAX/RossiXTe observation of the Z-type low mass X-ray binary Cygnus X-2. The source was in the so-called high overall intensity state and in less than 24 hours went through all three branches of the Z-track. The continuum X-ray spectrum could be described by the absorbed sum of a soft thermal component and a Comptonized component. The timing power spectrum showed several components including QPO in the ranges 28-50 Hz while the source was on the horizontal branch (HBO). We found that the HBO frequency was well correlated with the parameters of soft thermal component in the X-ray spectrum.

  9. Ultrafast Exciton Dynamics in CdxHg(1-x)Te alloy Quantum Dots

    NASA Astrophysics Data System (ADS)

    Leontiadou, Marina A.; Al-Otaify, Ali; Kershaw, Stephen V.; Zhovtiuk, Olga; Kalytchuk, Sergii; Mott, Derrick; Maenosono, Shinya; Rogach, Andrey L.; Binks, David J.

    2016-05-01

    Ultrafast transient absorption spectroscopy is used to investigate sub-nanosecond exciton dynamics in CdxHg(1-x)Te alloy colloidal quantum dots. A bleach was observed at the band gap due to state-filling, the mono-exponential decay of which had a characteristic lifetime of 91 ± 1 ps and was attributed to biexciton recombination; no evidence of surface-related trapping was observed. The rise time of the bleach, which is determined by the rate at which hot electrons cool to the band-edge, ranged between 1 and 5 ps depending on the pump photon energy. Measuring the magnitude of the bleach decay for different pump fluences and wavelengths allowed the quantum yield of multiple exciton generation to be determined, and was 115 ± 1% for pump photons with energy equivalent to 2.6 times the band gap.

  10. BLACK HOLE MASS AND SPIN FROM THE 2:3 TWIN-PEAK QPOs IN MICROQUASARS

    SciTech Connect

    Mondal, Soumen

    2010-01-10

    In the Galactic microquasars with double peak kHz quasi-periodic oscillations (QPOs) detected in X-ray fluxes, the ratio of the twin-peak frequencies is exactly, or almost exactly 2:3. This rather strongly supports the fact that they originate a few gravitational radii away from its center due to two modes of accretion disk oscillations. Numerical investigations suggest that post-shock matter, before they settle down in a subsonic branch, execute oscillations in the neighborhood region of 'shock transition'. This shock may excite QPO mechanism. The radial and vertical epicyclic modes of oscillating matter exactly match with these twin-peak QPOs. In fully general relativistic transonic flows, we investigate that shocks may form very close to the horizon around highly spinning Kerr black holes and appear as extremum in the inviscid flows. The extreme shock location provides upper limit of QPOs and hence fixes 'lower cutoff' of the spin. We conclude that the 2:3 ratio exactly occurs for spin parameters a >= 0.87 and almost exactly, for wide range of spin parameter, for example, XTE 1550-564, and GRO 1655-40 a>0.87, GRS 1915+105 a>0.83, XTE J1650-500 a>0.78, and H 1743-322 a>0.68. We also make an effort to measure unknown mass for XTE J1650-500(9.1 approx 14.1 M{sub sun}) and H 1743-322(6.6 approx 11.3 M{sub sun}).

  11. The formation of thermally evaporated stable Schottky barriers on p-ZnxPb(1-x)Te thin films

    NASA Astrophysics Data System (ADS)

    Khairnar, U. P.; Jadhav, S. R.

    2013-06-01

    Metal-semiconductor contacts are drawing increasing attention due to their potential for applications in devices and integrated circuits. Experimentally, lower barrier heights have been reported more often for metallic contacts on p-type semiconductors. Here we report our results regarding barrier heights of Ag/Au on p-ZnxPb(1-x)Te. The barrier heights can be perceived using data on the interface reaction and the phase formation in direct contacts with ZnxPb(1-x)Te. In such contacts which are normally thought to be responsible for the observation of low barrier heights on p-type semiconductor. Thermally stable Ag/Au-contacts with a barrier height of 0.56 eV were produced.

  12. Ion-implantation-induced damage and resonant levels in Pb/sub 1-x/Sn/sub x/Te

    SciTech Connect

    Gresslehner, K.H.; Palmetshofer, L.

    1980-09-01

    The dependence of the carrier concentration on the implantation dose and on the temperature was investigated in ion-implanted thin films of Pb/sub 1-x/Sn/sub x/Te (0< or =x<0.1). By assuming a twofold defect level in the conduction band we are able to fit the experimental results. With increasing tin content the energy of the defect level shifts towards the conduction-band edge. By extending the results to SnTe a general model for the understanding of the electrical properties of ion-implanted Pb/sub 1-x/Sn/sub x/Te (0< or =x< or =1) is suggested.

  13. Chemical analysis of anodic oxide layers based on Hg/sub 1-x/Cd/sub x/Te

    SciTech Connect

    Korsak, T.E.

    1987-02-01

    The goal of this work is to study the application of the photometric method in analyzing the composition of Hg/sub 1-x/Cd/sub x/Te solid solution anodic oxide with high accuracy and without preliminary separation of the elements. In order to determine cadmium content, a photometric measurement on a complex of this element with xylenol orange was used. Mercury concentration was determined using an extraction photometric method based on benzene extraction of chloride complexes of mercury anions with crystal violet. Tellurium content was determined by extraction with dichloroethane of bromide complexes of tellurium with diantipyrylpropylmethane. The authors synthesized diantipyrylpropylmethane as described. They studied single crystal Hg/sub 1-x/Cd/sub x/Te samples of random orientation with x = 0.2 and n-type conductivity.

  14. INTEGRAL measures the hard X-ray spectrum of the Be/X-ray binary XTE J1859+083

    NASA Astrophysics Data System (ADS)

    Malyshev, D.; Gotz, C. Ferrigno D.

    2015-04-01

    During the INTEGRAL observations performed from 2015 April 17, 19:47 to April 19, 20:01 UTC, the IBIS/ISGRI instrument detected a highly significant signal from a transient source, positionally coincident with the Be/X-ray pulsar XTE J1859+083 (ra, dec) = (284.78 ; 8.25) , which is reported to be in outburst since 2015-02-08 (ATeL #7034).

  15. Optical second-harmonic imaging of Pb{sub x}Cd{sub 1-x}Te ternary alloys

    SciTech Connect

    Scheidt, T.; Rohwer, E.G.; Bergmann, H.M. von; Saucedo, E.; Dieguez, E.; Fornaro, L.; Stafast, H.

    2005-05-15

    We employ femtosecond laser pulses (80 fs, 1.59 eV, and 80 MHz) to study the optical second-harmonic (SH) response of Pb{sub x}Cd{sub 1-x}Te ternary alloys (x about 0.2) grown by the vertical Bridgman method. The alloy segregates into a Pb-rich and a Cd-rich phase, the latter dominating the SH response of the ternary alloy by at least two orders of magnitude. Several sample regions show a regular layer-by-layer accommodation of the Pb-rich and Cd-rich phases as seen by a periodic alternation of the alloy's SH response on a {approx}10-{mu}m length scale. Furthermore, we employ polarization-resolved SH imaging as well as SH imaging at different azimuthal angles to obtain spatially resolved mappings of the sample, which are sensitive to the composition as well as the growth orientation of the Pb{sub x}Cd{sub 1-x}Te material system. We observe an azimuthal phase shift of approximately 30 deg. between coherent macroscopic regions (several mm{sup 2}) in the Cd-rich phase of the ternary alloy. We interpret these regions as large area crystalline grains of (111) and (411) crystal orientations and approximately equal composition. Hence, SH imaging is shown to spatially resolve regions of different growth directions within the Pb{sub x}Cd{sub 1-x}Te sample.

  16. Structural and chemical analysis of grain boundaries and tellurium precipitates in commercial Cd{sub 1{minus}x}Zn{sub x}Te

    SciTech Connect

    Heffelfinger, J.R.; Medlin, D.L.; James, R.B.

    1998-06-01

    The structure and chemistry of grain boundaries in commercial Cd{sub 1{minus}x}Zn{sub x}Te, prepared by the high-pressure Bridgman technique, have been analyzed using transmission electron microscopy, scanning electron microscopy, infrared-light microscopy and visible-light microscopy. These analyses show that the grain boundaries inside the Cd{sub 1{minus}x}Zn{sub x}Te materials are decorated with tellurium precipitates. Analysis of a tellurium precipitate at a grain boundary by transmission electron microscopy and selected-area electron diffraction found the precipitate to consist of a single, saucer-shaped grain. Electron diffraction from the precipitate was consistent with the trigonal phase of tellurium (space group P3{sub 1}21), which is the equilibrium phase at room temperature and atmospheric pressure. This precipitate was found to be aligned with one of the adjacent CZT grains such that the tellurium (0{bar 1}11) planes were nearly parallel to the CZT (111) planes. High-resolution transmission electron microscopy of the Te/Cd{sub 1{minus}x}Zn{sub x}Te interface showed no tertiary phase at the interface. The structures of the grain boundaries and the Te/Cd{sub 1{minus}x}Zn{sub x}Te interface are discussed and related to their possible implications on Cd{sub 1{minus}x}Zn{sub x}Te gamma-ray detector performance.

  17. Radio Disappearance of the Magnetar XTE J1810-197 and Continued X-ray Timing

    NASA Astrophysics Data System (ADS)

    Camilo, F.; Ransom, S. M.; Halpern, J. P.; Alford, J. A. J.; Cognard, I.; Reynolds, J. E.; Johnston, S.; Sarkissian, J.; van Straten, W.

    2016-04-01

    We report on timing, flux density, and polarimetric observations of the transient magnetar and 5.54 s radio pulsar XTE J1810-197 using the Green Bank, Nançay, and Parkes radio telescopes beginning in early 2006, until its sudden disappearance as a radio source in late 2008. Repeated observations through 2016 have not detected radio pulsations again. The torque on the neutron star, as inferred from its rotation frequency derivative \\dot{ν }, decreased in an unsteady manner by a factor of three in the first year of radio monitoring, until approximately mid-2007. By contrast, during its final year as a detectable radio source, the torque decreased steadily by only 9%. The period-averaged flux density, after decreasing by a factor of 20 during the first 10 months of radio monitoring, remained relatively steady in the next 22 months, at an average of 0.7 ± 0.3 mJy at 1.4 GHz, while still showing day-to-day fluctuations by factors of a few. There is evidence that during this last phase of radio activity the magnetar had a steep radio spectrum, in contrast to earlier flat-spectrum behavior. No secular decrease presaged its radio demise. During this time, the pulse profile continued to display large variations; polarimetry, including of a new profile component, indicates that the magnetic geometry remained consistent with that of earlier times. We supplement these results with X-ray timing of the pulsar from its outburst in 2003 up to 2014. For the first 4 years, XTE J1810-197 experienced non-monotonic excursions in frequency derivative by at least a factor of eight. But since 2007, its \\dot{ν } has remained relatively stable near its minimum observed value. The only apparent event in the X-ray record that is possibly contemporaneous with the radio shutdown is a decrease of ≈20% in the hot-spot flux in 2008-2009, to a stable, minimum value. However, the permanence of the high-amplitude, thermal X-ray pulse, even after the (unexplained) radio demise, implies

  18. Modification of band gap in surface layer in Cd 1-xZn xTe by YAG:Nd +3 laser radiation

    NASA Astrophysics Data System (ADS)

    Medvid, Artur; Fedorenko, Leonid L.; Korbutjak, Dmytro V.; Kryluk, Sergiy G.; Yusupov, Mikola M.; Mychko, Aleksandr

    2007-02-01

    A mechanism of formation of graded band-gap based on Thermogradient Effect (TGE) is proposed in Cd 1-xZn xTe at irradiation by second harmonic of a Q-switched YAG:Nd laser. According to the effect, the interstitial atoms of Cd (Cd i) in Cd 1-xZn xTe move along the temperature gradient while the Cd vacancies (V Cd) and Zn atoms - in the opposite direction, into the bulk of the semiconductor where temperature is lower. Photoluminescence (PL) spectra studied at 5 K show that concentration of Zn atoms increases due to aggregation of VCd with Zn after laser irradiation. Formation of a graded band-gap in Cd 1-xZn xTe crystal at irradiation by second harmonica of YAG:Nd laser by is shown to be possible.

  19. VLT spectroscopy of XTE J2123-058 during quiescence: the masses of the two components

    NASA Astrophysics Data System (ADS)

    Casares, J.; Dubus, G.; Shahbaz, T.; Zurita, C.; Charles, P. A.

    2002-01-01

    We present Very Large Telescope (VLT) low-resolution spectroscopy of the neutron star X-ray transient XTE J2123-058 during its quiescent state. Our data reveal the presence of a K7V companion which contributes 77 per cent to the total flux at λ6300 and orbits the neutron star at K2=287+/-12kms-1. Contrary to other soft X-ray transients (SXTs), the Hα emission is almost exactly in antiphase with the velocity curve of the optical companion. Using the light-centre technique we obtain K1=140+/-27kms-1 and hence q=K1/K2=M2/M1=0.49+/-0.10. This, combined with a previous determination of the inclination angle (i=73°+/-4°) yields M1=1.55+/-0.31Msolar and M2=0.76+/-0.22Msolar. M2 agrees well with the observed spectral type. Doppler tomography of the Hα emission shows a non-symmetric accretion disc distribution mimicking that seen in SW Sex stars. Although we find a large systemic velocity of - 110+/-8kms-1 this value is consistent with the galactic rotation velocity at the position of J2123-058, and hence a halo origin. The formation scenario of J2123-058 is still unresolved.

  20. On the Nature of XTE J0421+560/CI Cam

    NASA Technical Reports Server (NTRS)

    Belloni, T.; vandenAncker, M.; Dieters, S.; Fender, R.; Fox, D. W.; Kommers, J. M.; Lewin, W. H. G.; VanParadijs, J.

    1999-01-01

    We present the results of the analysis of RXTE, BATSE and optical/IR data of the 1998 outburst of the x-ray transient system XTE J0421+650. The x-ray outburst shows a very fast decay initial e-folding time approximately 0.5 days, slowing down to about 2.3 days). The X ray spectrum in the 2-25 keV band is thermal, softening considerably during decay. Intrinsic absorption is observed, also strongly variable. A strong iron line at around 6.7 keV is observed. No fast time variability is observed (<0.1 rms in the 1-4906 Hz band at peak). The analysis of optical/IR data suggest that the secondary is a b[e] star and place the system at a distance of about 2 kpc. At this distance the 2-25 keV luminosity is about 5 x 10(exp 37) erg/seconds. We compare the properties of this system with those of the Be/NS LMC transient A 0538-66 and suggest that CI cam is of a similar nature. The presence of strong radio emission during outburst indicates that the compact object could be a black hole.

  1. First Principles Calculations of Structural, Electronic, Thermodynamic and Thermal Properties of BaxSr1-xTe Ternary Alloys

    NASA Astrophysics Data System (ADS)

    Chelli, S.; Meradji, H.; Amara Korba, S.; Ghemid, S.; El Haj Hassan, F.

    2014-12-01

    The structural, electronic thermodynamic and thermal properties of BaxSr1-xTe ternary mixed crystals have been studied using the ab initio full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). In this approach, the Perdew-Burke-Ernzerhof-generalized gradient approximation (PBE-GGA) was used for the exchange-correlation potential. Moreover, the recently proposed modified Becke Johnson (mBJ) potential approximation, which successfully corrects the band-gap problem was also used for band structure calculations. The ground-state properties are determined for the cubic bulk materials BaTe, SrTe and their mixed crystals at various concentrations (x = 0.25, 0.5 and 0.75). The effect of composition on lattice constant, bulk modulus and band gap was analyzed. Deviation of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence (LCD) were observed for the ternary BaxSr1-xTe alloys. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers. On the other hand, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing, ΔHm as well as the phase diagram. It was shown that these alloys are stable at high temperature. Thermal effects on some macroscopic properties of BaxSr1-xTe alloys were investigated using the quasi-harmonic Debye model, in which the phononic effects are considered.

  2. The neutron star transient XTE J1701-407 has returned to quiescence after a 3-year long outburst

    NASA Astrophysics Data System (ADS)

    Degenaar, N.; Wijnands, R.; Altamirano, D.; Cackett, E.; Linares, M.; Homan, J.; Fridriksson, J.

    2011-08-01

    The neutron star low-mass X-ray binary and long thermonuclear burst source XTE J1701-407 (ATel #1618) has been active ever since its discovery in 2008 June (ATel #1569), displaying a typical 2-10 keV luminosity of ~5E36 erg/s (assuming a distance D=5.0 kpc; ATel #2814). However, routine monitoring of the Galactic bulge with the PCA aboard RXTE (Swank & Markwardt 2001, ASP conference series 251, 94) indicates that the outburst has now ceased: the source intensity has remained below the detection limit of the PCA since 2011 August 9 (see the link provided below).

  3. The multicolour optical monitoring of the High Mass X-ray Binary CI Cam/XTE J0421+560

    NASA Astrophysics Data System (ADS)

    Konstsntinova, T.; Larionov, V.; Kopatskaya, E.; Larionova, E.; Efimova, N.

    2014-07-01

    We analyse the photometric behaviour of the high-mass X-ray binary system CI Cam/XTE J0421+560. Our observations cover the time interval 1999-2014. The source was monitored with 70-cm AZT-8 (CrAO, Ukraine) and 0.4-m LX-200 (St.Petersburg, Russia) telescopes. During the monitoring period, CI Cam displayed two significant increases of brightness in the optical photometric bands. The first one follows the X-ray outburst that occurred in 1998 March. The second one started in 2013 and lasts until January - February of 2014.

  4. Terahertz radiation from Cd{sub x}Hg{sub 1-x}Te photoexcited by femtosecond laser pulses

    SciTech Connect

    Krotkus, A.; Adomavicius, R.; Molis, G.; Urbanowicz, A.; Eusebe, H.

    2004-10-01

    Terahertz radiation from Cd{sub x}Hg{sub 1-x}Te samples excited by femtosecond Ti:sapphire laser pulses were measured by using an ultrafast photoconductive antenna manufactured from low-temperature grown GaAs. Terahertz fields radiated by the samples of all three investigated alloy compositions with x=0, 0.2, and 0.3 were of the same order of magnitude. No azimuthal angle dependence of the radiated signal was detected, which evidences that linear current surge effect is dominating over nonlinear optical rectification.

  5. Non-linear behaviour of XTE J1550-564 during its 1998-1999 outburst, revealed by recurrence analysis

    NASA Astrophysics Data System (ADS)

    Suková, Petra; Janiuk, Agnieszka

    2016-06-01

    We study the X-ray emission of the microquasar XTE J1550-564 and analyze the properties of its light curves using the recurrence analysis method. The indicators for non-linear dynamics of the accretion flow are found in the very high state and soft state of this source. The significance of deterministic variability depends on the energy band. We discuss the non-linear dynamics of the accretion flow in the context of the disc-corona geometry and propagating oscillations in the accretion flow.

  6. Implication of the Observable Spectral Cutoff Energy Evolution in XTE J1550-564

    NASA Technical Reports Server (NTRS)

    Titarchuk, Lev; Shaposhnikov, Nikolai

    2010-01-01

    The physical mechanisms responsible for production of the non-thermal emission in accreting black holes should be imprinted in the observational appearances of the power law tails in the X-ray spectra from these objects. Variety of spectral states observed from galactic black hole binaries by it Rossi X-ray Timing Explorer (RXTE) allow examination of the photon upscattering under different accretion regimes. We revisit of RXTE data collected from the black hole X-ray binary XTE J1550-564 during two periods of X-ray activity in 1998 and 2000 focusing on the behavior of the high energy cutoff of the power law part of the spectrum. For the 1998 outburst the Iran- sition from the low-hard state to the intermediate state was accompanied by a gradual decrease in the cutoff energy which then showed a sharp reversal to a clear increasing trend during the further evolution towards the very high and high-soft states. However, the 2000 outburst showed only the decreasing part of this pattern. Notably, the photon indexes corresponding to the cutoff increase for the 1998 event are much higher than the index values reached during the 2000 rise transition. We attribute this difference in the cutoff' energy behav- for to the different partial contributions of the thermal and non-thermal (bulk motion) Comptonization in photon upscattering. Namely, during the 1998 event the higher accretion rate presumably provided more cooling to the Comptonizing media and thus reducing the effectiveness of the thermal upscattering process. Under these conditions the bulk motion takes a leading role in boosting the input soft photons. Monte Carlo simulations of the The physical mechanisms responsible for production of the non-thermal emission in accreting black holes should be imprinted in the observational apperances of the power law tails in the X-ray spectra from these objects. Variety of spectral states observed from galactic black hole binaries by it Rossi X-ray Timing Explorer (RXTE) allow

  7. Implication of the Observed Spectral Cutoff Energy Evolution in XTE J1550-564

    NASA Astrophysics Data System (ADS)

    Titarchuk, Lev; Shaposhnikov, Nikolai

    2010-12-01

    The physical mechanisms responsible for the production of non-thermal emission in accreting black holes (BHs) should be imprinted in the observational appearances of the power-law tails in the X-ray spectra from these objects. Phenomenology of different spectral states exhibited by galactic BH binaries allows us to establish the physics of the photon upscattering under different accretion regimes. We revisit the data collected by the Rossi X-ray Timing Explorer from the BH X-ray binary XTE J1550-564 during two periods of X-ray activity in 1998 and 2000 focusing on the behavior of the high-energy cutoff of the power-law part of the spectrum. For the 1998 outburst, the transition from the low-hard state to the intermediate state was accompanied by a gradual decrease in the cutoff energy. This was followed by an extended minimum which then showed an abrupt reversal to a clear increasing trend as the source evolved to the very high and high-soft states. The 2000 outburst showed only the decreasing and extended minimum portions of this pattern. We attribute this difference in the cutoff energy behavior to the different partial contributions of the thermal and non-thermal (bulk motion) Comptonization. Namely, during the 1998 event the higher accretion rate presumably provided more cooling to the Comptonizing media and thus reducing the effectiveness of the thermal upscattering process. Under these conditions, the bulk motion takes a leading role in boosting the input soft photons. Recent Monte Carlo simulations by Laurent & Titarchuk strongly support this scenario.

  8. Cd{sub 1−x}Mn{sub x}Te ultrasmall quantum dots growth in a silicate glass matrix by the fusion method

    SciTech Connect

    Dantas, Noelio Oliveira; Lima Fernandes, Guilherme de; Almeida Silva, Anielle Christine; Baffa, Oswaldo; Gómez, Jorge Antônio

    2014-09-29

    In this study, we synthesized Cd{sub 1−x}Mn{sub x}Te ultrasmall quantum dots (USQDs) in SiO{sub 2}-Na{sub 2}CO{sub 3}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass system using the fusion method. Growth of these Cd{sub 1−x}Mn{sub x}Te USQDs was confirmed by optical absorption, atomic force microscopy (AFM), magnetic force microscopy (MFM), scanning transmission electron microscopy (TEM), and electron paramagnetic resonance (EPR) measurements. The blueshift of absorption transition with increasing manganese concentration gives evidence of incorporation of manganese ions (Mn{sup 2+}) in CdTe USQDs. AFM, TEM, and MFM confirmed, respectively, the formation of high quality Cd{sub 1−x}Mn{sub x}Te USQDs with uniformly distributed size and magnetic phases. Furthermore, EPR spectra showed six lines associated to the S = 5/2 spin half-filled d-state, characteristic of Mn{sup 2+}, and confirmed that Mn{sup 2+} are located in the sites core and surface of the CdTe USQD. Therefore, synthesis of high quality Cd{sub 1−x}Mn{sub x}Te USQDs may allow the control of optical and magnetic properties.

  9. Quantum-interference effects in single- and poly-crystalline topological insulator Bi2-xTe3

    NASA Astrophysics Data System (ADS)

    Chiu, Shao-Pin; Lin, Juhn-Jong

    2014-03-01

    We have studied the carrier transport properties of both single- and poly-crystalline topological insulator (TI) Bi2-xTe3 samples. Single-crystalline microflakes were made by exfoliation from a single-crystalline Bi2Te3 bulk. Polycrystalline samples were made by flash evaporation of 5N purity Bi2Te3 sheets. In single-crystalline Bi2Te3 microflakes, temperature dependent resistances revealed two-dimensional (2D) electron-electron interaction effect. The extracted Coulomb screening parameter is negative, in accord with the situation of strong spin-orbit coupling in the TI materials. Positive magnetoresistances (MRs) originated from 2D weak-antilocalization (WAL) effect were measured in low magnetic fields, and satisfactorily described by a multichannel-conduction model. Especially, as T below 1 K and under high positive backgate voltages, signature of two coherent conduction channels was found. We discuss our results in terms of Dirac fermion states on the bottom surface, in addition to the bulk states. Polycrystalline Bi2-xTe3 thin films were patterned by electron-beam lithography. In low perpendicular magnetic fields, positive MRs due to the 2D WAL effect were observed. In parallel magnetic fields, Aharonov-Bohm oscillations were measured, suggesting the presence of metallic surface states. This work was supported by the Taiwan National Science Council through Grant No. NSC102-2120-M-009-003 (J.J.L.).

  10. Prediction of an arc-tunable Weyl Fermion metallic state in MoxW1-xTe2

    NASA Astrophysics Data System (ADS)

    Chang, Tay-Rong; Xu, Su-Yang; Chang, Guoqing; Lee, Chi-Cheng; Huang, Shin-Ming; Wang, Baokai; Bian, Guang; Zheng, Hao; Sanchez, Daniel; Belopolski, Ilya; Alidoust, Nasser; Neupane, Madhab; Bansil, Arun; Jeng, Horng-Tay; Lin, Hsin; Hasan, M. Zahid

    A Weyl semimetal is a new state of matter that hosts Weyl fermions as emergent quasiparticles. The Weyl fermions correspond to isolated points of bulk band degeneracy, Weyl nodes, which are connected only through the crystal's boundary by an exotic Fermi arc surface state. The length of the Fermi arc gives a measure of the topological strength, because the only way to destroy the Weyl nodes is to annihilate them in pairs in k space. To date, Weyl semimetals are only realized in the TaAs class. Here, we propose a tunable Weyl metallic state in MoxW1-xTe2 via our first-principles calculations, where the Fermi arc length can be continuously changed as a function of Mo concentration, thus tuning the topological strength of the system. Our results provide an experimentally feasible route to realizing Weyl physics in the layered compound MoxW1-xTe2 where non-saturating magneto-resistance and pressure driven superconductivity have been observed.

  11. Prediction of an arc-tunable Weyl Fermion metallic state in MoxW1-xTe2

    NASA Astrophysics Data System (ADS)

    Chang, Tay-Rong; Xu, Su-Yang; Chang, Guoqing; Lee, Chi-Cheng; Huang, Shin-Ming; Wang, Baokai; Bian, Guang; Zheng, Hao; Sanchez, Daniel S.; Belopolski, Ilya; Alidoust, Nasser; Neupane, Madhab; Bansil, Arun; Jeng, Horng-Tay; Lin, Hsin; Zahid Hasan, M.

    2016-02-01

    A Weyl semimetal is a new state of matter that hosts Weyl fermions as emergent quasiparticles. The Weyl fermions correspond to isolated points of bulk band degeneracy, Weyl nodes, which are connected only through the crystal's boundary by exotic Fermi arcs. The length of the Fermi arc gives a measure of the topological strength, because the only way to destroy the Weyl nodes is to annihilate them in pairs in the reciprocal space. To date, Weyl semimetals are only realized in the TaAs class. Here, we propose a tunable Weyl state in MoxW1-xTe2 where Weyl nodes are formed by touching points between metallic pockets. We show that the Fermi arc length can be changed as a function of Mo concentration, thus tuning the topological strength. Our results provide an experimentally feasible route to realizing Weyl physics in the layered compound MoxW1-xTe2, where non-saturating magneto-resistance and pressure-driven superconductivity have been observed.

  12. Type I X-ray Bursts from the Neutron-star Transient XTE J1701-462

    NASA Astrophysics Data System (ADS)

    Lin, Dacheng; Altamirano, Diego; Homan, Jeroen; Remillard, Ronald A.; Wijnands, Rudy; Belloni, Tomaso

    2009-07-01

    The neutron-star X-ray transient XTE J1701-462 was observed for ~3 Ms with RXTE during its 2006-2007 outburst. Here we report on the discovery of three type-I X-ray bursts from XTE J1701-462. They occurred as the source was in transition from the typical Z-source behavior to the typical atoll-source behavior, at ~10% of the Eddington luminosity. The first burst was detected in the Z-source flaring branch (FB); the second in the vertex between the FB and normal branches; and the third in the atoll-source soft state. The detection of the burst in the FB cast doubts on earlier speculations that the FB is due to unstable nuclear burning of accreted matter. The last two of the three bursts show photospheric radius expansion, from which we estimate the distance to the source to be 8.8 kpc with a 15% uncertainty. No significant burst oscillations in the range 30-4000 Hz were found during these three bursts.

  13. Reflection Spectroscopy of the Black Hole Binary XTE J1752-223 in the Bright Hard State

    NASA Astrophysics Data System (ADS)

    Garcia, Javier; Steiner, James F.; Grinberg, Victoria; McClintock, Jeffrey E.; Dauser, Thomas; Remillard, Ronald A.

    2016-04-01

    During its rise to maximum in 2009, XTE J1752-223 stalled for a full month in the bright hard state at about 30% of its peak (Eddington) luminosity. Along this extended period, 60 RXTE pointed observations showed the luminosity and hardness ratio of the source to be extraordinarily stable, resulting in a unique data set of exceptional quality. We combined all these 300 ks of RXTE data into a single PCA (3-45 keV) spectrum with 82 million counts and a single HEXTE spectrum (20-250 keV) with 10.4 million counts. Using our calibration tools PCACORR and HEXBCORR, we greatly enhanced the sensitivity of the detectors to faint spectral features, such as the Fe line and edge. Fitting the PCA+HEXTE spectrum using an advanced version of our reflection code, which includes a physical model of Comptonization, we constrained: the spin of the black hole (or alternatively the inner radius of the accretion disk); the inclination of the system; the ionization state and Fe abundance of the disk's atmosphere; and the temperature and optical depth of the corona. We compare these results with similar ones we reported earlier for GX 339-4 in the bright hard state. XTE J1752-223 and GX 339-4 are the first two of 29 black hole binaries we propose to study using recalibrated RXTE archival data and our reflection models.

  14. Prediction of an arc-tunable Weyl Fermion metallic state in Mo(x)W(1-x)Te2.

    PubMed

    Chang, Tay-Rong; Xu, Su-Yang; Chang, Guoqing; Lee, Chi-Cheng; Huang, Shin-Ming; Wang, BaoKai; Bian, Guang; Zheng, Hao; Sanchez, Daniel S; Belopolski, Ilya; Alidoust, Nasser; Neupane, Madhab; Bansil, Arun; Jeng, Horng-Tay; Lin, Hsin; Zahid Hasan, M

    2016-01-01

    A Weyl semimetal is a new state of matter that hosts Weyl fermions as emergent quasiparticles. The Weyl fermions correspond to isolated points of bulk band degeneracy, Weyl nodes, which are connected only through the crystal's boundary by exotic Fermi arcs. The length of the Fermi arc gives a measure of the topological strength, because the only way to destroy the Weyl nodes is to annihilate them in pairs in the reciprocal space. To date, Weyl semimetals are only realized in the TaAs class. Here, we propose a tunable Weyl state in Mo(x)W(1-x)Te2 where Weyl nodes are formed by touching points between metallic pockets. We show that the Fermi arc length can be changed as a function of Mo concentration, thus tuning the topological strength. Our results provide an experimentally feasible route to realizing Weyl physics in the layered compound Mo(x)W(1-x)Te2, where non-saturating magneto-resistance and pressure-driven superconductivity have been observed. PMID:26875819

  15. Ferromagnetism in Ge{sub 1-x}Cr{sub x}Te epilayers grown by molecular beam epitaxy

    SciTech Connect

    Fukuma, Y.; Asada, H.; Taya, T.; Irisa, T.; Koyanagi, T.

    2006-10-09

    IV-VI ferromagnetic semiconductor Ge{sub 1-x}Cr{sub x}Te has been grown on BaF{sub 2} (111) by molecular beam epitaxy. The ferromagnetism was clearly established by direct magnetization and Hall measurements. The experimental correlation between the anomalous Hall resistivity {rho}{sub xy} and the resistivity {rho}{sub xx}, {rho}{sub xy}{proportional_to}{rho}{sub xx}{sup 1.76}, is understood from the semiclassical nature of the charge carrier dynamics, suggesting that the ferromagnetism gives rise to p-d exchange interaction. The Curie temperature increases systematically from the substrate temperature T{sub S} of 300 to 250 to 200 deg. C and with increasing the Cr composition along with each T{sub S}.

  16. IV-VI diluted magnetic semiconductor Ge{sub 1-x}Mn{sub x}Te epilayer grown by molecular beam epitaxy

    SciTech Connect

    Fukuma, Y.; Goto, K.; Senba, S.; Miyawaki, S.; Asada, H.; Koyanagi, T.; Sato, H.

    2008-03-01

    Growth of the IV-VI diluted magnetic semiconductor Ge{sub 1-x}Mn{sub x}Te by molecular beam epitaxy is reported. The epitaxial growth of Ge{sub 1-x}Mn{sub x}Te (x=0.13) on BaF{sub 2} (111) with a GeTe buffer layer is confirmed by x-ray diffraction and reflection high-energy electron diffraction. The ferromagnetic order is clearly established by the magnetization and magnetotransport measurements. The Curie temperature of 100 K is obtained for the hole concentration of 7.86x10{sup 20} cm{sup -3}. The existence of the strong p-d exchange which gives rise to the ferromagnetic order is revealed by the hard x-ray photoemission measurements.

  17. Photovoltaic performances of Cu2-xTe sensitizer based on undoped and indium(3+)-doped TiO2 photoelectrodes and assembled counter electrodes.

    PubMed

    Srathongluan, Pornpimol; Kuhamaneechot, Rattanakorn; Sukthao, Prapatsawan; Vailikhit, Veeramol; Choopun, Supab; Tubtimtae, Auttasit

    2016-02-01

    Novel binary Cu2-xTe nanoparticles based on undoped and indium-doped TiO2 photoelectrodes were synthesized using a successive ionic layer adsorption and reaction (SILAR) technique as a sensitizer for liquid-junction solar cells. A larger diameter of TiO2 promoted a narrower energy band gap after indium doping, attributing to yield a broader absorption range of nanoparticle sensitizer due to the increasing amount of Cu2-xTe NPs on TiO2 surface. The atomic percentages showed the stoichiometric formation of Cu2Te incorporated in a Cu2-xTe structure. The best photovoltaic performance with the lower SILAR cycle, i.e., n=13 was performed after indium doping in both of carbon and Cu2S CEs and revealed that the efficiency of 0.73% under the radiant 100mW/cm(2) (AM 1.5G). The electrochemical impedance spectroscopy (EIS) was used to investigate the electrical properties via effect of material doping and counter electrodes with a lower charge-transfer resistance (Rct) and it was also found that the electron lifetime was improved after the sample doped with indium and assembled with carbon CE. PMID:26524258

  18. Charge Mediated Reversible Metal-Insulator Transition in Monolayer MoTe2 and WxMo1-xTe2 Alloy.

    PubMed

    Zhang, Chenxi; Kc, Santosh; Nie, Yifan; Liang, Chaoping; Vandenberghe, William G; Longo, Roberto C; Zheng, Yongping; Kong, Fantai; Hong, Suklyun; Wallace, Robert M; Cho, Kyeongjae

    2016-08-23

    Metal-insulator transitions in low-dimensional materials under ambient conditions are rare and worth pursuing due to their intriguing physics and rich device applications. Monolayer MoTe2 and WTe2 are distinguished from other TMDs by the existence of an exceptional semimetallic distorted octahedral structure (T') with a quite small energy difference from the semiconducting H phase. In the process of transition metal alloying, an equal stability point of the H and the T' phase is observed in the formation energy diagram of monolayer WxMo1-xTe2. This thermodynamically driven phase transition enables a controlled synthesis of the desired phase (H or T') of monolayer WxMo1-xTe2 using a growth method such as chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). Furthermore, charge mediation, as a more feasible method, is found to make the T' phase more stable than the H phase and induce a phase transition from the H phase (semiconducting) to the T' phase (semimetallic) in monolayer WxMo1-xTe2 alloy. This suggests that a dynamic metal-insulator phase transition can be induced, which can be exploited for rich phase transition applications in two-dimensional nanoelectronics. PMID:27415610

  19. Detection of a large Be circumstellar disk during X-ray quiescence of XTE J1946+274

    NASA Astrophysics Data System (ADS)

    Özbey Arabacı, M.; Camero-Arranz, A.; Zurita, C.; Gutiérrez-Soto, J.; Nespoli, E.; Suso, J.; Kiaeerad, F.; García-Rojas, J.; Kızıloǧlu, Ü.

    2015-10-01

    Aims: We present a multiwavelength study of the Be/X-ray binary system XTE J1946+274 with the main goal of better characterizing its behavior during X-ray quiescence. We also aim to shed light on the possible mechanisms which trigger the X-ray activity for this source. Methods: XTE J1946+274 was observed by Chandra-ACIS during quiescence in 2013 March 12. In addition, this source has been monitored from the ground-based astronomical observatories of El Teide (Tenerife, Spain), Roque de los Muchachos (La Palma, Spain) and Sierra Nevada (Granada, Spain) since 2011 September, and from the TÜBİTAK National Observatory (Antalya, Turkey) since 2005 April. We have performed spectral and photometric temporal analyses in order to investigate the quiescent state and transient behavior of this binary system. Results: Our optical study revealed that a long mass ejection event from the Be star took place in 2006, lasting for about seven years, and another one is currently ongoing. We also found that a large Be circumstellar disk is present during quiescence, although major X-ray activity is not observed. We made an attempt to explain this by assuming the permanently presence of a tilted (sometimes warped) Be decretion disk. The 0.3-10 keV X-ray spectrum of the neutron star during quiescence was well fitted with either an absorbed black-body or an absorbed power-law models. The main parameters obtained for these models were kT = 1.43 ± 0.17 and Γ = 0.9 ± 0.4 (with NH ~ 2-7 × 1022 cm-2). The 0.3-10 keV flux of the source was ~0.8-1 × 10-12 erg-1 cm-2 s-1. Pulsations were found with Ppulse = 15.757(1) s (epoch MJD 56 363.115) and an rms pulse fraction of 32.1(3)%. The observed X-ray luminosity during quiescent periods was close to that of expected in supersonic propeller regimen.

  20. Teaching "Candide": A Debate.

    ERIC Educational Resources Information Center

    Braun, Theodore E. D.; And Others

    1988-01-01

    Two different approaches to teaching Voltaire's "Candide", one deriving meaning from the textual fabric or "inside" of the story and the other focusing on the author's "external" intent in writing the story, are presented and compared. (MSE)

  1. ACCRETION TORQUES AND MOTION OF THE HOT SPOT ON THE ACCRETING MILLISECOND PULSAR XTE J1807-294

    SciTech Connect

    Patruno, Alessandro; Wijnands, R.; Van der Klis, Michiel; Hartman, Jacob M.; Chakrabarty, Deepto

    2010-07-10

    We present a coherent timing analysis of the 2003 outburst of the accreting millisecond pulsar (AMXP) XTE J1807-294. We find a 95% confidence interval for the pulse frequency derivative of (+0.7, + 4.7) x 10{sup -14} Hz s{sup -1} and (-0.6, + 3.8) x 10{sup -14} Hz s{sup -1} for the fundamental and second harmonics, respectively. The sinusoidal fractional amplitudes of the pulsations are the highest observed among AMXPs and can reach values of up to 27% (2.5-30 keV). The pulse arrival time residuals of the fundamental frequency follow a linear anti-correlation with the fractional amplitudes that suggests hot spot motion both in longitude and latitude over the surface of the neutron star. An anti-correlation between residuals and X-ray flux suggests an influence of the accretion rate on pulse phase and casts doubts on the interpretation of pulse frequency derivatives in terms of changes of spin rates and torques on the neutron star.

  2. Optical properties of Ge xSb 20- xTe 80 thin films and their changes by light illumination

    NASA Astrophysics Data System (ADS)

    Pamukchieva, V.; Szekeres, A.

    2008-03-01

    The influence of light illumination on the optical constants of chalcogenide thin films with non-stoichiometric Ge xSb 20- xTe 80 ( x = 15, 17, 19) composition is studied by spectral ellipsometry in the visible range of light. The films were deposited onto glass substrates by vacuum thermal evaporation of parent glasses and were subjected to an 1-h illumination with a 500 W HBO mercury lamp. It has been established that illumination of the films leads to a decrease of the refractive index, n, in the whole spectral region studied and to an increase of the extinction coefficient, k, in the range of 600-800 nm. The optical bandgap energy Eg values are within 0.55-0.76 eV with a tendency to increase with increasing the Ge content. Illumination resulted in a sharp decrease of the Eg values indicating structural change in the films. Leaving the films at atmospheric conditions the optical parameters values change toward their initial values of unilluminated state.

  3. Excitation of a non-radial mode in a millisecond X-ray pulsar XTE J1751-305

    NASA Astrophysics Data System (ADS)

    Lee, Umin

    2014-08-01

    We discuss non-radial modes in mass-accreting and rapidly rotating neutron stars for the coherent frequency detected in a millisecond X-ray pulsar XTE J1751-305. The spin frequency of the pulsar is νspin ≅ 435 Hz and the identified frequency is νosc = 0.572 7595 × νspin. Assuming that the frequency detected is that in the corotating frame of the star, we examine r and g modes in the surface layer of accreting matter composed mostly of helium, inertial and r modes in the fluid core, and toroidal modes in the solid crust. We find that the r modes of l' = m = 1 and 2 excited by ɛ-mechanism in the surface layer can give the ratio κ = νosc/νspin ≃ 0.57 at νspin = 435 Hz, where m and l' are the azimuthal wavenumber and the harmonic degree of the modes. We also suggest a toroidal crust mode and a core r mode destabilized by gravitational wave emission for the observed ratio κ. We find that the amplitude of the core r mode of l' = m = 2 can be amplified at the surface layer by a large factor famp ˜ 102 at νspin = 435 Hz for a M = 1.4 M⊙ neutron-star model. This amplification, however, may not be large enough for the r-mode amplitude to be consistent with an estimation by Mahmoodifar & Strohmayer (2013).

  4. Candidate CDTI procedures study

    NASA Technical Reports Server (NTRS)

    Ace, R. E.

    1981-01-01

    A concept with potential for increasing airspace capacity by involving the pilot in the separation control loop is discussed. Some candidate options are presented. Both enroute and terminal area procedures are considered and, in many cases, a technologically advanced Air Traffic Control structure is assumed. Minimum display characteristics recommended for each of the described procedures are presented. Recommended sequencing of the operational testing of each of the candidate procedures is presented.

  5. Deposition and characterization of Cd{sub 1−x}Mg{sub x}Te thin films grown by a novel cosublimation method

    SciTech Connect

    Kobyakov, Pavel S. Swanson, Drew E.; Sampath, Walajabad S.; Moore, Andrew; Raguse, John M.

    2014-03-15

    Photovoltaic cells utilizing the CdS/CdTe structure have improved substantially in the past few years. Despite the recent advances, the efficiency of CdS/CdTe cells is still significantly below their Shockley–Queisser limit. CdTe based ternary alloy thin films, such as Cd{sub 1−x}Mg{sub x}Te (CMT), could be used to improve efficiency of CdS/CdTe photovoltaic cells. Higher band gap Cd{sub 1−x}Mg{sub x}Te films can be the absorber in top cells of a tandem structure or an electron reflector layer in CdS/CdTe cells. A novel cosublimation method to deposit CMT thin films has been developed. This method can deposit CMT films of band gaps ranging from 1.5 to 2.3 eV. The cosublimation method is fast, repeatable, and scalable for large areas, making it suitable for implementing into large-scale manufacturing. Characterization of as-deposited CMT films, with x varying from 0 to 0.35, reveals a linear relationship between Mg content measured by energy dispersive x-ray spectroscopy and the optical band gap. Glancing angle x-ray diffraction (GAXRD) measurements of Cd{sub 1−x}Mg{sub x}Te films show a zinc-blende structure similar to CdTe. Furthermore, increasing Mg content decreases the lattice parameter and the grain size. GAXRD shows the films are under mild tension after deposition.

  6. MAXI/GSC detection of renewed X-ray activity of the neutron star X-ray binary XTE J1709-267

    NASA Astrophysics Data System (ADS)

    Nakahira, S.; Matsuoka, T. Mihara M.; Negoro, H.; Ueno, S.; Tomida, H.; Ishikawa, M.; Nakagawa, Y. E.; Sugawara, Y.; Sugizaki, M.; Serino, M.; Iwakiri, W.; Shidatsu, M.; Sugimoto, J.; Takagi, T.; Kawai, N.; Isobe, N.; Sugita, S.; Yoshii, T.; Tachibana, Y.; Ono, Y.; Fujiwara, T.; Yoshida, A.; Sakamoto, T.; Kawakubo, Y.; Kitaoka, Y.; Tsunemi, H.; Shomura, R.; Nakajima, M.; Tanaka, K.; Masumitsu, T.; Kawase, T.; Ueda, Y.; Kawamuro, T.; Hori, T.; Tanimoto, A.; Tsuboi, Y.; Nakamura, Y.; Sasaki, R.; Yamauchi, M.; Furuya, K.; Yamaoka, K.

    2016-06-01

    We report on a detection of X-ray outburst from XTE J1709-267 triggered by the MAXI/GSC nova alert system at 12:25 on 2016 May 31. The MAXI/GSC 2-6 keV X-ray flux on May 31 is 210 mCrab, which is brighter than the peak flux of the previous outburst in July 2012 (160 mCrab in 2-6 keV; Atel #5319, Asai, K. et al, PASJ 67, 92, 2015).

  7. Formation of acceptor centers under the action of redox media on the surface of Cd{sub x}Hg{sub 1-x}Te films

    SciTech Connect

    Varavin, V. S.; Sidorov, G. Yu.

    2009-12-15

    The effect of redox media on the formation of acceptor centers in the Cd{sub x}Hg{sub 1-x}Te films grown by molecular beam epitaxy on the GaAs (301) substrates is studied. When tested for long-term stability, the untreated n-type films do not change their parameters, whereas the treated films exhibit a decrease in the conductivity and the mobility of charge carriers by nearly two orders of magnitude. It is shown that, on the treatments, a source of acceptors is formed at the surface, and the acceptors are most likely mercury vacancies.

  8. Analysis of variability in the burst oscillations of the accreting millisecond pulsar XTE J1814-338

    NASA Technical Reports Server (NTRS)

    Watts, Anna L.; Strohmayer, Tod E.; Markwardt, Craig B.

    2005-01-01

    The accreting millisecond pulsar XTE J1814-338 exhibits oscillations at the known spin frequency during Type I X-ray bursts. The properties of the burst oscillations reflect the nature of the thermal asymmetry on the stellar surface. We present an analysis of the variability of the burst oscillations of this source, focusing on three characteristics: fractional amplitude, harmonic content and frequency. Fractional amplitude and harmonic content constrain the size, shape and position of the emitting region, whilst variations in frequency indicate motion of the emitting region on the neutron star surface. We examine both long-term variability over the course of the outburst, and short-term variability during the bursts. For most of the bursts, fractional amplitude is consistent with that of the accretion pulsations, implying a low degree of fuel spread. There is however a population of bursts whose fractional amplitudes are substantially lower, implying a higher degree of fuel spread, possibly forced by the explosive burning front of a precursor burst. For the first harmonic, substantial differences between the burst and accretion pulsations suggest that hotspot geometry is not the only mechanism giving rise to harmonic content in the latter. Fractional amplitude variability during the bursts is low; we can only rule out the hypothesis that the fractional amplitude remains constant at the l(sigma) level for bursts that do not exhibit photospheric radius expansion (PRE). There are no significant variations in frequency in any of the bursts except for the one burst that exhibits PRE. This burst exhibits a highly significant but small (= 0.1Hz) drop in frequency in the burst rise. The timescale of the frequency shift is slower than simple burning layer expansion models predict, suggesting that other mechanisms may be at work.

  9. ALA Candidates: Presidential Timbre

    ERIC Educational Resources Information Center

    Berry, John N., III

    2010-01-01

    This article presents an interview with two effective spokespeople, notable school librarian Sara Kelly Johns and retired public library administrator Molly Raphael, who compete to be American Library Association (ALA) president. One of them will be elected president of ALA for a year's term beginning in July 2011. Each candidate comes from a…

  10. Growth and characterization of CdTe single quantum wells confined by Cd 1- xZn xTe alloy and short period CdTe/ZnTe superlattice

    NASA Astrophysics Data System (ADS)

    Magnea, N.; Lentz, G.; Mariette, H.; Feuillet, G.; Dal'bo, F.; Tuffigo, H.

    1989-02-01

    A comparative study of structural and optical properties of CdTe single quantum wells has been performed. Very efficient CdTe-Cd 1-xZn xTe (x Zn ≤ 0.2) wells have been grown and short period superlattices appear as a promising substitute of the alloy.

  11. Erratum: "Photoionization Modeling of Oxygen K Absorption in the Interstellar Medium, the Chandra Grating Spectra of XTE J1817-330" (2013, Apj, 768, 60)

    NASA Technical Reports Server (NTRS)

    Gatuzz, E.; Garcia, J.; Mendoza, C.; Kallman, Timothy R.; Witthoeft, Michael C.; Lohfink, A.; Bautista, M. A.; Palmeri, P.; Quinet, P.

    2013-01-01

    In the published version of this paper, there are some minor inaccuracies in the absorption-line wavelengths listed in Table 4 as a result of a faulty reduction procedure of the Obs6615 spectrum. The shifts have been detected in a comparison with the wavelengths listed for this spectrum in the Chandra Transmission Grating Catalog and Archive (TGCat8). They are due to incorrect centroid positions of the zero-order image in both reductions as determined by the tgdetect utility which, when disentangled, yield the improved line positions of the amended Table 4 given below. It must also be pointed out that other quantitative findings of the original paper: 1. Table 5, p. 9: the column density (NH), ionization parameter, oxygen abundance of the warmabs model and the normalization and photon index of the power-law model; 2. Table 6, p. 9: the hydrogen column density of the warmabs fit; 3. Table 7, p. 9: the present oxygen equivalent widths of XTE J1817-330; and 4. Table 8, p. 10: the present oxygen column densities of XTE J1817-330 derived from both the curve of growth and warmabs model fit have been revised in the new light and are, within the estimated uncertainty ranges, in good accord with the new rendering.

  12. A new approach to the crystal growth of Hg 1- xMn xTe by the cold travelling heater method (CTHM)

    NASA Astrophysics Data System (ADS)

    Reig, C.; Gómez-García, C. J.; Muñoz, V.

    2001-03-01

    In order to obtain crystals with a homogeneous composition and to reduce the Hg high pressure related to the temperature synthesis reaction between the components in elemental form, Hg 1- xMn xTe bulk crystals were produced by the cold travelling heater method (CTHM). Following the technique initially proposed for the growth of CdHgTe by the Triboulet group, the feed material was a split ingot of two segments, one of HgTe and the other of MnTe, with cross-sectional areas chosen to establish the desired final composition. The growth was carried out at a temperature of 600°C and a rate of 2 mm/h. The Hg 1- xMn xTe crystals have been characterised by scanning electron microscopy, including energy dispersive X-ray analysis and backscattered mode, powder X-ray diffractometry, Fourier transformed infrared spectroscopy, and SQUID magnetic susceptibility measurements. The crystals, with standard magnetic properties, show an excellent axial and radial composition uniformity throughout most of the total ingot length.

  13. Modeling the polarization of high-energy radiation from accreting black holes. A case study of XTE J1118+480

    NASA Astrophysics Data System (ADS)

    Vieyro, F. L.; Romero, G. E.; Chaty, S.

    2016-03-01

    Context. The high-energy emission (400 keV-2 MeV) of Cygnus X-1, which is the best-studied Galactic black hole, was recently found to be strongly polarized. The origin of this radiation is still unknown. Aims: We suggest that the emission is the result of non-thermal processes in the hot corona around the accreting compact object and study the polarization of high-energy radiation that is expected for black hole binaries. Methods: Two contributions to the total magnetic field were taken into account in our study: a small-scale random component related to the corona, and an ordered magnetic field associated with the accretion disk. The degree of polarization of gamma-ray emission for this particular geometry was estimated together with the angle of the polarization vector. Results: We obtain that the configuration of corona plus disk can account for the high degree of polarization of gamma-rays that are detected in galactic black holes and does not need to invoke a relativistic jet. We make specific predictions for sources in a low-hard state. In particular, the model is applied to the transient source XTE J1118+480. We show that if a new outburst of XTE J1118+480 is observed, then its gamma-ray polarization should be measurable by future instruments, such as ASTRO-H or the proposed ASTROGAM.

  14. Conduction mechanisms in p-type Pb{sub 1-x}Eu{sub x}Te alloys in the insulator regime

    SciTech Connect

    Peres, M. L.; Rubinger, R. M.; Ribeiro, L. H.; Rubinger, C. P. L.; Ribeiro, G. M.; Chitta, V. A.; Rappl, P. H. O.; Abramof, E.

    2012-06-15

    Electrical resistivity measurements were performed on p-type Pb{sub 1-x}Eu{sub x}Te films with Eu content x = 4%, 5%, 6%, 8%, and 9%. The well-known metal-insulator transition that occurs around 5% at room temperature due to the introduction of Eu is observed, and we used the differential activation energy method to study the conduction mechanisms present in these samples. In the insulator regime (x > 6%), we found that band conduction is the dominating conduction mechanism for high temperatures with carriers excitation between the valence band and the 4f levels originated from the Eu atoms. We also verified that mix conduction dominates the low temperatures region. Samples with x = 4% and 5% present a temperature dependent metal insulator transition and we found that this dependence can be related to the relation between the thermal energy k{sub B}T and the activation energy {Delta}{epsilon}{sub a}. The physical description obtained through the activation energy analysis gives a new insight about the conduction mechanisms in insulating p-type Pb{sub 1-x}Eu{sub x}Te films and also shed some light over the influence of the 4f levels on the transport process in the insulator region.

  15. The Transient Accreting X-Ray Pulsar XTE J1946+274: Stability of X-Ray Properties at Low Flux and Updated Orbital Solution

    NASA Astrophysics Data System (ADS)

    Marcu-Cheatham, Diana M.; Pottschmidt, Katja; Kühnel, Matthias; Müller, Sebastian; Falkner, Sebastian; Caballero, Isabel; Finger, Mark H.; Jenke, Peter J.; Wilson-Hodge, Colleen A.; Fürst, Felix; Grinberg, Victoria; Hemphill, Paul B.; Kreykenbohm, Ingo; Klochkov, Dmitry; Rothschild, Richard E.; Terada, Yukikatsu; Enoto, Teruaki; Iwakiri, Wataru; Wolff, Michael T.; Becker, Peter A.; Wood, Kent S.; Wilms, Jörn

    2015-12-01

    We present a timing and spectral analysis of the X-ray pulsar XTE J1946+274 observed with Suzaku during an outburst decline in 2010 October and compare with previous results. XTE J1946+274 is a transient X-ray binary consisting of a Be-type star and a neutron star with a 15.75 s pulse period in a 172 days orbit with 2-3 outbursts per orbit during phases of activity. We improve the orbital solution using data from multiple instruments. The X-ray spectrum can be described by an absorbed Fermi-Dirac cut-off power-law model along with a narrow Fe Kα line at 6.4 keV and a weak Cyclotron Resonance Scattering Feature (CRSF) at ˜35 keV. The Suzaku data are consistent with the previously observed continuum flux versus iron line flux correlation expected from fluorescence emission along the line of sight. However, the observed iron line flux is slightly higher, indicating the possibility of a higher iron abundance or the presence of non-uniform material. We argue that the source most likely has only been observed in the subcritical (non-radiation dominated) state since its pulse profile is stable over all observed luminosities and the energy of the CRSF is approximately the same at the highest (˜5 × 1037 erg s-1) and lowest (˜5 × 1036 erg s-1) observed 3-60 keV luminosities.

  16. Dark matter candidates

    SciTech Connect

    Turner, M.S.

    1989-01-01

    One of the simplest, yet most profound, questions we can ask about the Universe is, how much stuff is in it, and further what is that stuff composed of. Needless to say, the answer to this question has very important implications for the evolution of the Universe, determining both the ultimate fate and the course of structure formation. Remarkably, at this late date in the history of the Universe we still do not have a definitive answer to this simplest of questions---although we have some very intriguing clues. It is known with certainty that most of the material in the Universe is dark, and we have the strong suspicion that the dominant component of material in the Cosmos is not baryons, but rather is exotic relic elementary particles left over from the earliest, very hot epoch of the Universe. If true, the Dark Matter question is a most fundamental one facing both particle physics and cosmology. The leading particle dark matter candidates are: the axion, the neutralino, and a light neutrino species. All three candidates are accessible to experimental tests, and experiments are now in progress. In addition, there are several dark horse, long shot, candidates, including the superheavy magnetic monopole and soliton stars. 13 refs.

  17. Photoionization Modeling of Oxygen K Absorption in the Interstellar Medium: The Chandra Grating Spectra of XTE J1817-330

    NASA Technical Reports Server (NTRS)

    Gatuzz, E.; Garcia, J.; Menodza, C.; Kallman, T. R.; Witthoeft, M.; Lohfink, A.; Bautista, M. A.; Palmeri, P.; Quinet, P.

    2013-01-01

    We present detailed analyses of oxygen K absorption in the interstellar medium (ISM) using four high-resolution Chandra spectra towards the X-ray low-mass binary XTE J1817-330. The 11-25 A broadband is described with a simple absorption model that takes into account the pileup effect and results in an estimate of the hydrogen column density. The oxygen K-edge region (21-25 A) is fitted with the physical warmabs model, which is based on a photoionization model grid generated with the XSTAR code with the most up-to-date atomic database. This approach allows a benchmark of the atomic data which involves wavelength shifts of both the K lines and photoionization cross sections in order to fit the observed spectra accurately. As a result we obtain: a column density of N(sub H) = 1.38 +/- 0.01 x 10(exp 21) cm(exp -2); ionization parameter of log xi = .2.70 +/- 0.023; oxygen abundance of A(sub O) = 0.689(exp +0.015./-0.010); and ionization fractions of O I/O = 0.911, O II/O = 0.077, and O III/O = 0.012 that are in good agreement with previous studies. Since the oxygen abundance in warmabs is given relative to the solar standard of Grevesse and Sauval (1998), a rescaling with the revision by Asplund et al. (2009) yields A(sub O) = 0.952(exp +0.020/-0.013, a value close to solar that reinforces the new standard. We identify several atomic absorption lines.K-alpha , K-beta, and K-gamma in O I and O II; and K-alpha in O III, O VI, and O VII--last two probably residing in the neighborhood of the source rather than in the ISM. This is the first firm detection of oxygen K resonances with principal quantum numbers n greater than 2 associated to ISM cold absorption.

  18. Photoionization Modeling of Oxygen K Absorption in the Interstellar Medium:. [The Chandra Grating Spectra of XTE J1817-330

    NASA Technical Reports Server (NTRS)

    Gatuzz, E.; Garcia, J.; Mendoza, C.; Kallman, T. R.; Witthoeft, M.; Lohfink, A.; Bautista, M. A.; Palmeri, P.; Quinet, P.

    2013-01-01

    We present detailed analyses of oxygen K absorption in the interstellar medium (ISM) using four high-resolution Chandra spectra toward the X-ray low-mass binary XTE J1817-330. The 11-25 Angstrom broadband is described with a simple absorption model that takes into account the pile-up effect and results in an estimate of the hydrogen column density. The oxygen K-edge region (21-25 Angstroms) is fitted with the physical warmabs model, which is based on a photoionization model grid generated with the xstar code with the most up-to-date atomic database. This approach allows a benchmark of the atomic data which involves wavelength shifts of both the K lines and photoionization cross sections in order to fit the observed spectra accurately. As a result we obtain a column density of N(sub H) = 1.38 +/- 0.01 × 10(exp 21) cm(exp -2); an ionization parameter of log xi = -2.70 +/- 0.023; an oxygen abundance of A(sub O) = 0.689 (+0.015/-0.010); and ionization fractions of O(sub I)/O = 0.911, O(sub II)/O = 0.077, and O(sub III)/O = 0.012 that are in good agreement with results from previous studies. Since the oxygen abundance in warmabs is given relative to the solar standard of Grevesse & Sauval, a rescaling with the revision by Asplund et al. yields A(sub O) = 0.952(+0.020/-0.013), a value close to solar that reinforces the new standard.We identify several atomic absorption lines-K(alpha), K(beta), and K(gamma) in O(sub I) and O(sub II) and K(alpha) in O(sub III), O(sub VI), and O(sub VII)-the last two probably residing in the neighborhood of the source rather than in the ISM. This is the first firm detection of oxygen K resonances with principal quantum numbers n greater than 2 associated with ISM cold absorption.

  19. PHOTOIONIZATION MODELING OF OXYGEN K ABSORPTION IN THE INTERSTELLAR MEDIUM: THE CHANDRA GRATING SPECTRA OF XTE J1817-330

    SciTech Connect

    Gatuzz, E.; Mendoza, C.; Garcia, J.; Lohfink, A.; Kallman, T. R.; Witthoeft, M.; Bautista, M. A.; Palmeri, P.; Quinet, P. E-mail: claudio@ivic.gob.ve E-mail: alohfink@astro.umd.edu E-mail: michael.c.witthoeft@nasa.gov E-mail: palmeri@umons.ac.be

    2013-05-01

    We present detailed analyses of oxygen K absorption in the interstellar medium (ISM) using four high-resolution Chandra spectra toward the X-ray low-mass binary XTE J1817-330. The 11-25 A broadband is described with a simple absorption model that takes into account the pile-up effect and results in an estimate of the hydrogen column density. The oxygen K-edge region (21-25 A) is fitted with the physical warmabs model, which is based on a photoionization model grid generated with the XSTAR code with the most up-to-date atomic database. This approach allows a benchmark of the atomic data which involves wavelength shifts of both the K lines and photoionization cross sections in order to fit the observed spectra accurately. As a result we obtain a column density of N{sub H} = 1.38 {+-} 0.01 Multiplication-Sign 10{sup 21} cm{sup -2}; an ionization parameter of log {xi} = -2.70 {+-} 0.023; an oxygen abundance of A{sub O}= 0.689{sup +0.015}{sub -0.010}; and ionization fractions of O I/O = 0.911, O II/O = 0.077, and O III/O = 0.012 that are in good agreement with results from previous studies. Since the oxygen abundance in warmabs is given relative to the solar standard of Grevesse and Sauval, a rescaling with the revision by Asplund et al. yields A{sub O}=0.952{sup +0.020}{sub -0.013}, a value close to solar that reinforces the new standard. We identify several atomic absorption lines-K{alpha}, K{beta}, and K{gamma} in O I and O II and K{alpha} in O III, O VI, and O VII-the last two probably residing in the neighborhood of the source rather than in the ISM. This is the first firm detection of oxygen K resonances with principal quantum numbers n > 2 associated with ISM cold absorption.

  20. The Internal-Candidate Syndrome

    ERIC Educational Resources Information Center

    Barden, Dennis M.

    2008-01-01

    In this article, the author explains the complications involved when an internal candidate is included in an open search for a leadership position in an academic institution. Internal-candidate syndrome is a dilemma faced by institutions when they have to choose between an internal candidate and an external one. There are two reasons why…

  1. Candidate Assembly Statistical Evaluation

    Energy Science and Technology Software Center (ESTSC)

    1998-07-15

    The Savannah River Site (SRS) receives aluminum clad spent Material Test Reactor (MTR) fuel from all over the world for storage and eventual reprocessing. There are hundreds of different kinds of MTR fuels and these fuels will continue to be received at SRS for approximately ten more years. SRS''s current criticality evaluation methodology requires the modeling of all MTR fuels utilizing Monte Carlo codes, which is extremely time consuming and resource intensive. Now that amore » significant number of MTR calculations have been conducted it is feasible to consider building statistical models that will provide reasonable estimations of MTR behavior. These statistical models can be incorporated into a standardized model homogenization spreadsheet package to provide analysts with a means of performing routine MTR fuel analyses with a minimal commitment of time and resources. This became the purpose for development of the Candidate Assembly Statistical Evaluation (CASE) program at SRS.« less

  2. Phase separation and exchange biasing in the ferromagnetic IV-VI semiconductor Ge{sub 1-x}Mn{sub x}Te

    SciTech Connect

    Lechner, R. T.; Springholz, G.; Hassan, M.; Groiss, H.; Kirchschlager, R.; Stangl, J.; Hrauda, N.; Bauer, G.

    2010-07-12

    Ferromagnetic Ge{sub 1-x}Mn{sub x}Te grown by molecular beam epitaxy with Mn content of x{sub Mn}approx =0.5 is shown to exhibit a strong tendency for phase separation. At higher growth temperatures apart from the cubic Ge{sub 0.5}Mn{sub 0.5}Te, a hexagonal MnTe and a rhombohedral distorted Ge{sub 0.83}Mn{sub 0.17}Te phase is formed. This coexistence of antiferromagnetic MnTe and ferromagnetic Ge{sub 0.5}Mn{sub 0.5}Te results in magnetic exchange-bias effects.

  3. Hg-loss compensation and wiping-off of source liquid on slider liquid phase epitaxy of Hg 1- xCd xTe

    NASA Astrophysics Data System (ADS)

    Shinohara, Motoya; Nugraha; Noda, Yasutoshi; Furukawa, Yoshitaka

    1994-08-01

    Hg loss measurement and wiping the liquid source on Hg 1- xCd xTe (MCT) layer growth were performed using a slider liquid phase epitaxy (LPE) boat with a HgTe reservoir. The optimum conditions to compensate Hg loss were revealed, where an increased amount of HgTe in the reservoir was effective to stabilize the weight change of source liquid due to Hg evaporation. The wiping was effectively made on equilibrium cooling from the melting point, where thin MCT layers (2-4 μm) resulted and the surface was slightly terraced. Thick layers (30-40 μm) resulted from the supercooling and step cooling with a supercooling of 15 K. The composition of the grown layers was x = 0.25-0.42.

  4. Abundancias químicas de la compañera visible del agujero negro binario V4641 Sgr (XTE J1819-254)

    NASA Astrophysics Data System (ADS)

    Cúneo, V. A.; Jofré, E.; Pintado, O. I.; Gómez, M. N.

    2015-08-01

    In this work we expose an analysis of the chemical abundances of the optical companion of the confirmed black hole binary V4641 Sgr (XTE J1819-254) from GMOS spectra obtained with the Gemini North telescope. This analysis allowed to observe an enhancement of N, O, Mg and Si, attributed to the contamination of heavy elements generated during the supernova explosion that gave birth to the black hole. It was also observed that Cr and Fe were subabundant. The aim of this study is to test the formation scenario of a binary system containing a black hole as remnant of the supernova explosion of a massive star, and to provide information to better understand the final stages in the evolution of massive stars and black hole progenitors.

  5. The reaction kinetics of Cu with the CdTe(111)-B surface: Formation of metastable Cu{sub x}Te (x{approx}2)

    SciTech Connect

    Teeter, Glenn

    2005-11-08

    In the present study, elemental Cu is deposited on the clean CdTe(111)-B surface and annealed in vacuum. Surface-composition maps generated by scanning Auger microcopy provide evidence that a reaction occurs between Cu and the CdTe(111)-B substrate that results in the formation of a metastable copper telluride phase Cu{sub x}Te (x{approx}2) at the surface. In situ thermal-desorption mass spectrometry measurements show that elemental Cd is released during the reaction and desorbs from the surface. Desorption of Te from the substrate is suppressed during the reaction. Analysis of Cd desorption traces demonstrates that the Cu+CdTe(111)-B reaction proceeds via zero-order kinetics, with an activation energy of 180{+-}5 kJ mol{sup -1}.

  6. Influence of samarium on the thermoelectric figure of merit of Sm{sub x}Pb{sub 1-x}Te alloys

    SciTech Connect

    Aliev, F. F. Hasanov, H. A.

    2012-03-15

    The temperature and concentration dependences of the electrical (conductivity {sigma}, the Hall coefficient R), thermoelectric (thermovoltage {alpha}), and thermal (thermal conductivity K{sub tot}) characteristics of Sm{sub x}Pb{sub 1-x}Te alloys (x = 0, 0.02, 0.04, 0.08) are studied in the temperature range 100-500 K. Using the data for {sigma}, {alpha}, and K{sub tot}, the thermoelectric power {alpha}{sup 2}{sigma}, figure of merit Z, and efficiency {delta} are calculated. It is established that at room-temperature {alpha}{sup 2}{sigma} and Z peak at the hole concentration p Almost-Equal-To 1.2 Multiplication-Sign 10{sup 18} cm{sup -3}.

  7. Spin-glass behavior and anomalous magnetoresistance in ferromagnetic Ge{sub 1-x}Fe{sub x}Te epilayer

    SciTech Connect

    Liu, Jindong; Cheng, Xiaomin Tong, Fei; Miao, Xiangshui

    2014-07-28

    We report that the Ge{sub 1-x}Fe{sub x}Te thin film exhibits spin-glass behavior when the Fe concentration increases to 0.08. A large bifurcation between the zero-field cooling and field cooling temperature-dependent magnetization was observed. The hysteresis loops after zero-field cooling and field cooling show an exchange bias effect. A time-dependent thermoremanent magnetization follows power-law decay, which confirms the existence of spin glass. The anomalous magnetotranport properties present a further evidence for spin-glass behavior and give a freezing temperature T{sub g} ∼ 5 K in the Ge{sub 0.92}Fe{sub 0.08}Te thin film.

  8. Constraints on braneworld gravity models from a kinematic limit on the age of the black hole XTE J1118+480.

    PubMed

    Psaltis, Dimitrios

    2007-05-01

    In braneworld gravity models with a finite anti-de Sitter space (AdS) curvature in the extra dimension, the AdS/conformal field theory correspondence leads to a prediction for the lifetime of astrophysical black holes that is significantly smaller than the Hubble time, for asymptotic curvatures that are consistent with current experiments. Using the recent measurements of the position, three-dimensional spatial velocity, and mass of the black hole XTE J1118+480, I calculate a lower limit on its kinematic age of > or =11 Myr (95% confidence). This translates into an upper limit for the asymptotic AdS curvature in the extra dimensions of <0.08 mm, which significantly improves the limit obtained by table top experiments of sub mm gravity. PMID:17501556

  9. Mechanisms of recombination of nonequilibrium charge carriers in epitaxial Cd{sub x}Hg{sub 1-x}Te (x = 0.20-0.23) layers

    SciTech Connect

    Ikusov, D. G.; Sizov, F. F.; Staryi, S. V. Teterkin, V. V.

    2007-02-15

    The experimental temperature dependences of the photosensitivity and the data on the lifetime of nonequilibrium charge carriers in epitaxial Cd{sub x}Hg{sub 1-x}Te layers with x = 0.20-0.23 were used to show that, in the region of intrinsic and extrinsic conductivity in n-type films grown by molecular beam epitaxy, CHCC Auger recombination is the prevailing recombination mechanism. At the same time, in p-type films grown by liquid-or vapor-phase epitaxy, it is observed that, in the region of extrinsic conductivity, CHLH Auger recombination competes with Shockley-Read recombination. The n-type films grown by molecular beam epitaxy contain a much lower concentration of recombination centers than the p-type films grown by liquid-or gasphase epitaxy.

  10. Optimal bandgap variants of Cd 1- xZn xTe for high-resolution X-ray and gamma-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Toney, J. E.; Schlesinger, T. E.; James, R. B.

    1999-06-01

    We show that the trade-off between noise and charge generation statistics in Cd 1- xZn xTe leads to an optimal band gap of approximately 2.0 eV at room temperature. This implies a ZnTe fraction of approximately 0.7-0.8. We show that for X-rays and relatively low energy gamma-rays Cd 0.2Zn 0.8Te theoretically offers a significant potential improvement in energy resolution over Cd 0.9Zn 0.1Te even if compensation of shallow levels is less complete and carrier lifetimes are an order of magnitude lower for the higher x variant. We also show that these calculations are consistent with observed detector performance reported by many workers over a large period of time.

  11. ON THE NATURE OF QUASI-PERIODIC OSCILLATION PHASE LAGS IN BLACK HOLE CANDIDATES

    SciTech Connect

    Shaposhnikov, Nikolai E-mail: lev@milkyway.gsfc.nasa.gov

    2012-06-20

    Observations of quasi-periodic oscillations (QPOs) in X-ray binaries hold a key to understanding many aspects of these enigmatic systems. Complex appearance of the Fourier phase lags related to QPOs is one of the most puzzling observational effects in accreting black holes (BHs). In this Letter we show that QPO properties, including phase lags, can be explained in a framework of a simple scenario, where the oscillating media provide feedback on the emerging spectrum. We demonstrate that the QPO waveform is presented by the product of a perturbation and time-delayed response factors, where the response is energy dependent. The essential property of this effect is its nonlinear and multiplicative nature. Our multiplicative reverberation model successfully describes the QPO components in energy-dependent power spectra as well as the appearance of the phase lags between signals in different energy bands. We apply our model to QPOs observed by the Rossi X-Ray Timing Explorer in BH candidate XTE J1550-564. We briefly discuss the implications of the observed energy dependence of the QPO reverberation times and amplitudes on the nature of the power-law spectral component and its variability.

  12. Evolution of a Low Luminosity Outburst of the Black Hole Candidate H1743-322

    NASA Technical Reports Server (NTRS)

    Swank, J.; Markwardt, C.; Rupen, M.; Mioduszewski, A.; Dhawa, V.

    2005-01-01

    The black hole candidate X-ray transient H1743-322 = IGR J1746-3213 = XTE J17464-3213 had a bright outburst starting in March 2003, which reached a peak flux around 1.3 Crab and lasted nearly 2/3 of a year. After a similar period in apparent quiescence (below approx. 1 mCrab), the source began another outburst in July 2004, this time rising only to about 1/4 Crab and decaying in about 4.5 months. It appeared with an optically thick disk and a steep power law component (number index approx. 3), and began a steady increase, with mild spectral change. After 50 days, a hard power-law component appeared, along with low frequency quasiperiodic oscillations. Gradual decay of both components began, but after another month the soft component dropped faster and left the source in a harder state to continue the decay. The Very Large Array found no radio activity during the first month, but a 2 mJy radio source appeared during the X-ray rise. Evidence for jet ejection corresponding to changes in the X-ray source will be discussed in connection with interpretation of the system.

  13. On the Nature of QPO Phase Lags in Black Hole Candidates

    NASA Technical Reports Server (NTRS)

    Shaposhnikov, Nikolai

    2012-01-01

    Observations of quasi-periodic oscillations (QPOs) in X-ray binaries hold a key to understanding many aspects of these enigmatic systems. Complex appearance of the Fourier phase lags related to QPOs is one of the most puzzling observational effects in accreting black holes. In this Letter we show that QPO properties, including phase lags, can be explained in a framework of a simple scenario, where the oscillating media provides a feedback on the emerging spectrum. We demonstrate that the QPO waveform is presented by the product of a perturbation and a time delayed response factors, where the response is energy dependent. The essential property of this effect is its non-linear and multiplicative nature. Our multiplicative reverberation model successfully describes the QPO components in energy dependent power spectra as well as the appearance of the phase lags between signal in different energy bands. We apply our model to QPOs observed by Rossi X-ray Timing Explorer in BH candidate XTE J1550-564. We briefly discuss the implications of the observed energy dependence of the QPO reverberation times and amplitudes to the nature of the power law spectral component and its variability.

  14. A SPECTRAL STUDY OF THE RAPID TRANSITIONS OF TYPE-B QUASI-PERIODIC OSCILLATIONS IN THE BLACK HOLE TRANSIENT XTE J1859+226

    SciTech Connect

    Sriram, K.; Choi, C. S.; Rao, A. R.

    2013-09-20

    The fast transitions of type-B and type-A quasi-periodic oscillations (QPOs) are rarely found, and they are observed at the peak of the outburst in black hole transient (BHT) sources. The associated spectral variations during such events are crucial to understand the origin and location of such QPOs in the accretion disk. During the 1999 outburst of XTE J1859+226, on four occasions a rapid transition of type-B/A QPOs was noted. We performed broadband spectral analysis on these four observations to unveil the responsible spectral parameter causing the rapid transitions. After invoking simple spectral models, it was observed that disk parameters were consistently varying along with disk and power-law fluxes, and almost no change was noted in the power-law index parameter. Though using a complex physical model showed consistent results, the spectral parameter variations across the transitions were not significant. It was observed that the type-B QPO was always associated with an inner disk front which is closer to the BH. In one observation, a type-A QPO appeared as the source count rate suddenly dropped, and the power-law index as well as disk normalization parameter considerably changed during this transition. The spectral changes in this particular observation were similar to the changes observed in XTE J1817-330, indicating a common underlying mechanism. We have also examined a similar observation of BHT source GX 339-4, where a sudden transition of a type-A/B QPO was noted. Similar spectral study again revealed that the disk parameters were changing. We discuss the results in the framework of a truncated disk model and conclude that the movement of the coupled inner disk-corona region is responsible for such rapid transitions of type-B QPOs.

  15. 2009 Elections: The Candidates Statements

    ERIC Educational Resources Information Center

    TechTrends: Linking Research and Practice to Improve Learning, 2009

    2009-01-01

    This article presents the candidates for the 2009 Association for Educational Communications and Technology (AECT) election and their statements. The candidates are: (1) Andy Gibbons (President-Elect); (2) Barbara B. Lockee (President-Elect); (3) Mary Jean Bishop (At-Large Representative); and (4) Deepak Subramony (At-Large Representative). In…

  16. Determination of Black Hole Masses in Galactic Black Hole Binaries Using Scaling of Spectral and Variability Characteristics

    NASA Astrophysics Data System (ADS)

    Shaposhnikov, Nickolai; Titarchuk, Lev

    2009-07-01

    We present a study of correlations between X-ray spectral and timing properties observed from a number of Galactic black hole (BH) binaries during hard-soft state spectral evolution. We analyze 17 transition episodes from eight BH sources observed with Rossi X-Ray Timing Explorer. Our scaling technique for BH mass determination uses a correlation between the spectral index and quasi-periodic oscillation (QPO) frequency. In addition, we use a correlation between the index and the normalization of the disk "seed" component to cross-check the BH mass determination and estimate the distance to the source. While the index-QPO correlations for two given sources contain information on the ratio of the BH masses in those sources, the index-normalization correlations depend on the ratio of the BH masses and the distance square ratio. In fact, the index-normalization correlation also discloses the index-mass accretion rate saturation effect given that the normalization of disk "seed" photon supply is proportional to the disk mass accretion rate. We present arguments that this observationally established index saturation effect is a signature of the bulk motion (converging) flow onto a BH, which was early predicted by the dynamical Comptonization theory. We use GRO J1655 - 40 as a primary reference source for which the BH mass, distance, and inclination angle are evaluated by dynamical measurements with unprecedented precision among other Galactic BH sources. We apply our scaling technique to determine BH masses and distances for Cygnus X-1, GX 339 - 4, 4U 1543 - 47, XTE J1550 - 564, XTE J1650 - 500, H 1743 - 322, and XTE J1859 - 226. A good agreement of our results for sources with known values of BH masses and distance provides independent verification for our scaling technique.

  17. Imaging X-Ray, Optical, and Infrared Observations of the Transient Anomalous X-Ray Pulsar XTE J1810-197

    NASA Astrophysics Data System (ADS)

    Gotthelf, E. V.; Halpern, J. P.; Buxton, M.; Bailyn, C.

    2004-04-01

    We report X-ray imaging, timing, and spectral studies of XTE J1810-197, a 5.54 s pulsar discovered by Ibrahim and coworkers in recent Rossi X-Ray Timing Explorer (RXTE) observations. In a set of short exposures with the High Resolution Camera on board the Chandra X-Ray Observatory, we detect a strongly modulated signal (55%+/-4% pulsed fraction) with the expected period located at (J2000) 18h09m51s08, -19deg43'51.7", with a uncertainty radius of 0.6" (90% confidence level). Spectra obtained with XMM-Newton are well fitted by a two-component model that typically describes anomalous X-ray pulsars (AXPs), an absorbed blackbody plus power law with parameters kT=0.67+/-0.01 keV, Γ=3.7+/-0.2, NH=(1.05+/-0.05)×1022 cm-2, and FX(0.5-10keV)=3.98×10-11 ergs cm-2 s-1. Alternatively, a two-temperature blackbody fit is just as acceptable. The location of CXOU J180951.0-194351 is consistent with a point source seen in archival Einstein, ROSAT, and ASCA images, when its flux was nearly 2 orders of magnitude fainter, and from which no pulsations are found. The spectrum changed dramatically between the ``quiescent'' and ``active'' states; the former can be modeled as a softer blackbody. Using XMM-Newton timing data, we place an upper limit of 0.03 lt-s on any orbital motion in the period range 10 minutes-8 hr. Optical and infrared images obtained on the SMARTS 1.3 m telescope at the Cerro Tololo Inter-American Observatory (CTIO) show no object in the Chandra error circle to limits V=22.5, I=21.3, J=18.9, and K=17.5. Together, these results argue that CXOU J180951.0-194351 is an isolated neutron star, one most similar to the transient AXP AX J1844.8-0256. Continuing study of XTE J1810-197 in various states of luminosity is important for understanding and possibly unifying a growing class of isolated, young neutron stars that are not powered by rotation.

  18. Superconductivity in the orthorhombic phase of thermoelectric CsPbxBi4-xTe6 with 0.3≤x≤1.0

    NASA Astrophysics Data System (ADS)

    Zhang, R. X.; Yang, H. X.; Tian, H. F.; Chen, G. F.; Wu, S. L.; Wei, L. L.; Li, J. Q.

    2015-12-01

    Experimental measurements clearly reveal the presence of bulk superconductivity in the CsPbxBi4-xTe6 (0.3≤x≤1.0) materials, i.e. the first member of the thermoelectric series of Cs[PbmBi3Te5+m], these materials have the layered orthorhombic structure containing infinite anionic [PbBi3Te6]- slabs separated with Cs+ cations. Temperature dependences of electrical resistivity, magnetic susceptibility, and specific heat have consistently demonstrated that the superconducting transition in Cs0.96Pb0.25Bi3.75Te6.04 occurs at Tc=3.1 K, with a superconducting volume fraction close to 100% at 1.8 K. Structural study using aberration-corrected STEM/TEM reveals a rich variety of microstructural phenomena in correlation with the Pb-ordering and chemical inhomogeneity. The superconducting material Cs0.96Pb0.25Bi3.75Te6.04 with the highest Tc shows a clear ordered structure with a modulation wave vector of q≈a*/2+c*/1.35 on the a-c plane. Our study evidently demonstrates that superconductivity deriving upon doping of narrow-gap semiconductor is a viable approach for exploration of novel superconductors.

  19. The use of pulse processing techniques to improve the performance of Cd{sub 1{minus}x}Zn{sub x}Te gamma-ray spectrometers

    SciTech Connect

    Lund, J.C.; Olsen, R.; Van Scyoc, J.M.; James, R.B.

    1996-06-01

    Cd{sub 1{minus}x}Zn{sub x}Te (CZT) has recently shown great promise for use as a room temperature gamma-ray detector material. The availability of large volume (>1 cm{sup 3}) high resistivity CZT crystals has allowed the demonstration of detectors much larger than can be built with the similar material CdTe. However, CZT--like many other room-temperature materials--suffers from the poor transport properties of holes. The poor hole drift properties of CZT cause the characteristic hole tailing in gamma-ray pulse height spectra. The authors have applied pulse processing methods to reduce the hole tailing effects and improve the energy resolution of CZT detectors. They have used two signal processing methods to reduce hole tailing in CZT detectors: digital rise-time compensation and dual time-constant sampling. They discuss the implementation of these techniques, demonstrate results obtained in the laboratory, and compare the performance obtained with other detector systems.

  20. ON THE NATURE OF THE FIRST TRANSIENT Z SOURCE XTE J1701-462: ITS ACCRETION DISK STRUCTURE, NEUTRON STAR MAGNETIC FIELD STRENGTH, AND HARD TAIL

    SciTech Connect

    Ding, G. Q.; Wang, N.; Yan, S. P.; Zhang, S. N.; Qu, J. L. E-mail: dinggq@gmail.com

    2011-08-15

    Using data from the Rossi X-Ray Timing Explorer, we investigate the spectral evolution along a 'Z' track and a '{nu}' track on the hardness-intensity diagrams of the first transient Z source XTE J1701-462. The spectral analyses suggest that the inner disk radius depends on the mass accretion rate, in agreement with the model prediction, R{sub in}{proportional_to}M-dot{sup 2/7}{sub disk}, for a radiation-pressure-dominated accretion disk interacting with the magnetosphere of a neutron star (NS). The changes in the disk mass accretion rate M-dot{sub disk} are responsible for the evolution of the 'Z' or '{nu}' track. Radiation pressure thickens the disk considerably and also produces significant outflows. The NS surface magnetic field strength, derived from the interaction between the magnetosphere and the radiation-pressure-dominated accretion disk, is {approx}(1-3) x 10{sup 9} G, which is possibly between normal atoll and Z sources. A significant hard tail is detected in the horizontal branches and we discuss several possible origins of the hard tail.

  1. Jet-dominated quiescent state in black hole X-ray binaries: the cases of A0620-00 and XTE J1118+480

    NASA Astrophysics Data System (ADS)

    Yang, Qi-Xiang

    2016-04-01

    The radiative mechanism of black hole X-ray transients (BHXTs) in their quiescent states (defined as the 2-10 keV X-ray luminosity ≲ 1034 erg s-1) remains unclear. In this work, we investigate the quasi-simultaneous quiescent state spectrum (including radio, infrared, optical, ultraviolet and X-ray) of two BHXTs, A0620-00 and XTE J1118+480. We find that these two sources can be well described by a coupled accretion - jet model. More specifically, most of the emission (radio up to infrared, and the X-ray waveband) comes from the collimated relativistic jet. Emission from hot accretion flow is totally insignificant, and it can only be observed in mid-infrared (the synchrotron peak). Emission from the outer cold disk is only evident in the UV band. These results are consistent with our previous investigation on the quiescent state of V404 Cyg and confirm that the quiescent state is jet-dominated.

  2. 76 FR 4896 - Call for Candidates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-27

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Call for Candidates AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice... Federal Accounting Standards Advisory Board (FASAB) is currently seeking candidates (candidates must...

  3. Quasar candidates near 1057 + 01

    SciTech Connect

    Crampton, D.; Cartledge, S.; Cowley, A.P.; Hartwick, F.D.A. Arizona State Univ., Tempe Victoria Univ. )

    1991-04-01

    Positions and magnitudes are given for 143 quasar candidates and three white dwarf candidates discovered with the CFHT blue grens in a 2.7 square degree area in the direction 1057 + 01. The goal of this survey is to provide complete samples of quasars to study the large scale distribution of matter at moderate to high (z less than 3.4) redshifts. Part of the region surveyed in this paper was previously studied by Crampton and Parmar (1983), allowing a comparison of the search and measurements accuracies. Redshifts, derived from MMT spectroscopy, for 27 of the candidates are also presented. One quasar, 1058.1 + 0052, displays strong broad absorption lines characteristic of BAL quasars. 5 refs.

  4. Dependence of the electrical parameters of MBE-grown Cd{sub x}Hg{sub 1} {sub -} {sub x}Te films on the level of doping with indium

    SciTech Connect

    Varavin, V. S. Dvoretskii, S. A.; Ikusov, D. G.; Mikhailov, N. N.; Sidorov, Yu. G.; Sidorov, G. Yu.; Yakushev, M. V.

    2008-06-15

    Dependences of the minority-carrier lifetime and electron mobility in Cd{sub x}Hg{sub 1-x}Te films on their indium-doping level are studied. Films with x {approx} 0.22 grown by molecular-beam epitaxy on GaAs substrates were in situ doped with indium across their entire thickness. The temperature dependences of the lifetime were studied in the temperature range 77-300 K. The decrease in the lifetime, observed as the doping level increases, is governed by the mechanism of Auger recombination. As the doping level becomes higher, the mobility decreases in qualitative agreement with theoretical calculations.

  5. Interviewing Teacher-Librarian Candidates

    ERIC Educational Resources Information Center

    Yucht, Alice

    2004-01-01

    When recently asked by an administrator for some realistic questions and "recommended" responses to expect while interviewing candidates for school library positions, the author grouped the questions into three categories: library management, information skills and teaching skills. In this article are the questions she suggested, along with topics…

  6. Candidate gene prioritization with Endeavour.

    PubMed

    Tranchevent, Léon-Charles; Ardeshirdavani, Amin; ElShal, Sarah; Alcaide, Daniel; Aerts, Jan; Auboeuf, Didier; Moreau, Yves

    2016-07-01

    Genomic studies and high-throughput experiments often produce large lists of candidate genes among which only a small fraction are truly relevant to the disease, phenotype or biological process of interest. Gene prioritization tackles this problem by ranking candidate genes by profiling candidates across multiple genomic data sources and integrating this heterogeneous information into a global ranking. We describe an extended version of our gene prioritization method, Endeavour, now available for six species and integrating 75 data sources. The performance (Area Under the Curve) of Endeavour on cross-validation benchmarks using 'gold standard' gene sets varies from 88% (for human phenotypes) to 95% (for worm gene function). In addition, we have also validated our approach using a time-stamped benchmark derived from the Human Phenotype Ontology, which provides a setting close to prospective validation. With this benchmark, using 3854 novel gene-phenotype associations, we observe a performance of 82%. Altogether, our results indicate that this extended version of Endeavour efficiently prioritizes candidate genes. The Endeavour web server is freely available at https://endeavour.esat.kuleuven.be/. PMID:27131783

  7. Candidate cave entrances on Mars

    USGS Publications Warehouse

    Cushing, Glen E.

    2012-01-01

    This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

  8. SAO RAS SN candidates classifications

    NASA Astrophysics Data System (ADS)

    Fatkhullin, T. A.; Moskvitin, A. S.

    2016-08-01

    We observed SN candidates (AT 2016eow, AT 2016enu and AT 2016enf) with the BTA/Scorpio-I on August, 4. Direct images in the R band and long-slit spectra in the range of 3600-7600AA (resolution FWHM = 10A) were obtained.

  9. Candidate Exercise Technologies and Prescriptions

    NASA Technical Reports Server (NTRS)

    Loerch, Linda H.

    2010-01-01

    This slide presentation reviews potential exercise technologies to counter the effects of space flight. It includes a overview of the exercise countermeasures project, a review of some of the candidate exercise technologies being considered and a few of the analog exercise hardware devices, and a review of new studies that are designed to optimize the current and future exercise protocols.

  10. Empathy Development in Teacher Candidates

    ERIC Educational Resources Information Center

    Boyer, Wanda

    2010-01-01

    Using a grounded theory research design, the author examined 180 reflective essays of teacher candidates who participated in a "Learning Process Project," in which they were asked to synthesize and document their discoveries about the learning process over the course of a completely new learning experience as naive learners. This study explored…

  11. Modeling of electron energy spectra and mobilities in semi-metallic Hg{sub 1−x}Cd{sub x}Te quantum wells

    SciTech Connect

    Melezhik, E. O. Gumenjuk-Sichevska, J. V.; Sizov, F. F.

    2015-11-21

    Electron mobility, energy spectra, and intrinsic carrier concentrations in the n-type Hg{sub 0.32}Cd{sub 0.68}Te/Hg{sub 1−x}Cd{sub x}Te/Hg{sub 0.32}Cd{sub 0.68}Te quantum well (QW) in semi-metallic state are numerically modeled. Energy spectra and wave functions were calculated in the framework of the 8-band k-p Hamiltonian. In our model, electron scattering on longitudinal optical phonons, charged impurities, and holes has been taken into account, and the mobility has been calculated by an iterative solution of the Boltzmann transport equation. Our results show that the increase of the electron concentration in the well enhances the screening of the 2D electron gas, decreases the hole concentration, and can ultimately lead to a high electron mobility at liquid nitrogen temperatures. The increase of the electron concentration in the QW could be achieved in situ by delta-doping of barriers or by applying the top-gate potential. Our modeling has shown that for low molar composition x the concentration of holes in the well is high in a wide range of electron concentrations; in this case, the purity of samples does not significantly influence the electron mobility. These results are important in the context of establishing optimal parameters for the fabrication of high-mobility Hg{sub 1−x}Cd{sub x}Te quantum wells able to operate at liquid nitrogen temperature and thus suitable for applications in terahertz detectors.

  12. Characterization of CdTe substrates and MOCVD Cd 1- xZn xTe epilayers by Raman, photoluminescence and X-ray diffraction techniques

    NASA Astrophysics Data System (ADS)

    Levy, M.; Amir, N.; Khanin, E.; Muranevich, A.; Nemirovsky, Y.; Beserman, R.

    1998-05-01

    CdTe substrates and the quality of the Cd 1- xZn xTe ( x⩽0.1) epilayers grown by metalorganic chemical vapor deposition (MOCVD) on CdTe substrates, are characterized by Raman scattering and photoluminescence (PL) as well as by X-ray double-crystal rocking curve (DCRC). At a low temperature the intensity of LO phonon is enhanced wherever there is a structural defect. The defect-induced enhancement is due to a large momentum transfer which enhances the intraband Frolich interaction. In addition, the bound exciton peak intensity measured by PL decreases wherever the LO phonon scattering efficiency increases confirming that the defect is the origin of the above Raman enhancement. The quantitative measure of the structural perfection is related to the ratio between the defect band and excitonic peaks in the PL spectra, and correlates with the X-ray full-width at half-maximum (FWHM) of the layer peak. It is shown that in addition to these parameters, the FWHM of the PL defect band is a useful parameter to determine the quality of the epilayer, and a good correlation is obtained between the different parameters. The effect of growth parameters such as zinc partial pressure in the reactor during growth and the reactor design are studied. The results indicate that crystalline imperfection is caused by lattice mismatch between the CdTe substrate and the CdZnTe epilayer and by the nonuniformity of the zinc composition throughout the layers. The quality of the layers is independent of the reactor volume.

  13. XTE J1701-462 AND ITS IMPLICATIONS FOR THE NATURE OF SUBCLASSES IN LOW-MAGNETIC-FIELD NEUTRON STAR LOW-MASS X-RAY BINARIES

    SciTech Connect

    Homan, Jeroen; Fridriksson, Joel K.; Remillard, Ronald A.; Lewin, Walter H. G.; Van der Klis, Michiel; Wijnands, Rudy; Altamirano, Diego; Mendez, Mariano; Lin Dacheng; Casella, Piergiorgio; Belloni, Tomaso M.

    2010-08-10

    We report on an analysis of Rossi X-Ray Timing Explorer data of the transient neutron star low-mass X-ray binary (NS-LMXB) XTE J1701-462, obtained during its 2006-2007 outburst. The X-ray properties of the source changed between those of various types of NS-LMXB subclasses. At high luminosities, the source switched between two types of Z source behavior and at low luminosities we observed a transition from Z source to atoll source behavior. These transitions between subclasses primarily manifest themselves as changes in the shapes of the tracks in X-ray color-color (CD) and hardness-intensity diagrams (HID), but they are accompanied by changes in the kHz quasi-periodic oscillations, broadband variability, burst behavior, and/or X-ray spectra. We find that for most of the outburst the low-energy X-ray flux is a good parameter to track the gradual evolution of the tracks in CD and HID, allowing us to resolve the evolution of the source in greater detail than before and relate the observed properties to other NS-LMXBs. We further find that during the transition from Z to atoll, characteristic behavior known as the atoll upper banana can equivalently be described as the final stage of a weakening Z source flaring branch, thereby blurring the line between the two subclasses. Our findings strongly suggest that the wide variety in behavior observed in NS-LXMBs with different luminosities can be linked through changes in a single variable parameter, namely the mass accretion rate, without the need for additional differences in the neutron star parameters or viewing angle. We briefly discuss the implications of our findings for the spectral changes observed in NS-LMXBs and suggest that, contrary to what is often assumed, the position along the color-color tracks of Z sources is not determined by the instantaneous mass accretion rate.

  14. OPTOPUS observations of quasar candidates.

    NASA Astrophysics Data System (ADS)

    Cristiani, S.

    1987-06-01

    OPTOPUS is a fiber-optic instrument for multiple-object spectroscopy with the Boiler & Chivens spectrograph and a CCD detector at the 3.6-m telescope. The system has been described in detail by the Optical Instrumentation Group (1985, The Messenger 41,25). Its application for observing Halley's comet has been reported by Lund and Surdej (1986, The Messenger 43, 1). Here another "classical" use of multiple-object spectroscopy is presented: followup observations of quasar candidates.

  15. Metal Nitrides Grown from Ca/Li Flux: Ca6Te3N2 and New Nitridoferrate(I) Ca6(LixFe1-x)Te2N3.

    PubMed

    Dickman, Matthew J; Latturner, Susan E

    2016-08-24

    Two new tellurium-containing nitrides were grown from reactions in molten calcium and lithium. The compound Ca6Te3N2 crystallizes in space group R3̅c (a = 12.000(3)Å, c = 13.147(4)Å; Z = 6); its structure is an anti-type of rinneite (K3NaFeCl6) and 2H perovskite related oxides such as Sr3Co2O6. The compound Ca6(LixFe1-x)Te2N3 where x ≈ 0.48 forms in space group P42/m (a = 8.718(3)Å, c = 6.719(2)Å; Z = 2) with a new stuffed anti-type variant of the Tl3BiCl6 structure. Band structure calculations and easily observable red/green dichroic behavior indicate that Ca6Te3N2 is a highly anisotropic direct band gap semiconductor (Eg = 2.5 eV). Ca6(LixFe1-x)Te2N3 features isolated linear N-Fe-N units with iron in the rare Fe(1+) state. The magnetic behavior of the iron site was characterized by magnetic susceptibility measurements, which indicate a very high magnetic moment (5.16μB) likely due to a high degree of spin-orbit coupling. Inherent disorder at the Fe/Li mixed site frustrates long-range communication between magnetic centers. PMID:27479366

  16. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, some of the 1998 astronaut candidate class (group 17) take a close look at the Saturn V rocket on display. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters.

  17. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Some of the 1998 astronaut candidate class (group 17) take a close look at displays in the Apollo/Saturn V Center at KSC. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters.

  18. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, some of the 1998 astronaut candidate class (group 17) line up for a photo while standing under the engines of the Saturn V rocket on display. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters.

  19. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, some of the 1998 astronaut candidate class (group 17) line up for a photo during a tour of facilities at KSC. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF and the crew headquarters.

  20. Environmentally friendly lubricating oil candidate.

    PubMed

    Ozgülsün, A; Karaosmanoğlu, F

    1999-01-01

    Synthetic lubricating oils based on renewable sources, excluding petroleum, have a great importance among all of the lubricating oil alternatives that are included in the research field about clean and environmentally friendly lubricating oil technologies. One of the environmentally friendly lubricating oils is a vegetable oil-based product. In this study, the esterification product of oleic acid with a fraction of molasses fusel oil as a lubricating oil candidate was determined according to the American Society for Testing and Materials (ASTM) standard tests. The results indicate that the ester product can be used as an environmental friendly lubricating oil or lubricating oil additive. PMID:10399269

  1. Wasson's alternative candidates for soma.

    PubMed

    Riedlinger, T J

    1993-01-01

    Citing recently published challenges to R. Gordon Wasson's identification of Vedic soma as the psychoactive mushroom Amanita muscaria (fly-agaric), this article reviews unpublished letters by Wasson in which he considered and rejected other psychoactive plants as candidates, including the mint Lagochilus inebrians, Convolvulaceae (morning glory) seeds, the fungal parasite Claviceps purpurea (ergot), and especially the psilocybin mushroom Stropharia cubensis, known also as Psilocybe cubensis. Apart from their historical interest, these letters--from the Tina and Gordon Wasson Ethnomycological Collection at the Harvard Botanical Museum--demonstrate that Wasson remained open to refinements of his theory. PMID:8377083

  2. Kepler Discovers Earth-size Planet Candidates

    NASA Video Gallery

    NASA's Kepler mission has discovered its first Earth-size planet candidates and its first candidates in the habitable zone, a region where liquid water could exist on a planet's surface. Five of th...

  3. Four Republican Presidential Candidates Debate Educational Issues.

    ERIC Educational Resources Information Center

    Equity and Excellence, 1988

    1988-01-01

    Provides the transcript of a September 1987 debate on educational issues between Republican presidential candidates Jack Kemp and Pierre du Pont. Interspersed throughout the transcript are written responses to questions submitted to additional candidates Robert Dole and George Bush. (BJV)

  4. A DIRECT MEASUREMENT OF THE HEAT RELEASE IN THE OUTER CRUST OF THE TRANSIENTLY ACCRETING NEUTRON STAR XTE J1709-267

    SciTech Connect

    Degenaar, N.; Miller, J. M.; Wijnands, R.

    2013-04-20

    The heating and cooling of transiently accreting neutron stars provides a powerful probe of the structure and composition of their crust. Observations of superbursts and cooling of accretion-heated neutron stars require more heat release than is accounted for in current models. Obtaining firm constraints on the depth and magnitude of this extra heat is challenging and therefore its origin remains uncertain. We report on Swift and XMM-Newton observations of the transient neutron star low-mass X-ray binary XTE J1709-267, which were made in 2012 September-October when it transitioned to quiescence after a {approx_equal}10 week long accretion outburst. The source is detected with XMM-Newton at a 0.5-10 keV luminosity of L{sub X} {approx_equal} 2 Multiplication-Sign 10{sup 34}(D/8.5 kpc){sup 2} erg s{sup -1}. The X-ray spectrum consists of a thermal component that fits to a neutron star atmosphere model and a non-thermal emission tail, each of which contribute {approx_equal}50% to the total flux. The neutron star temperature decreases from {approx_equal}158 to {approx_equal}152 eV during the {approx_equal}8 hr long observation. This can be interpreted as cooling of a crustal layer located at a column density of y {approx_equal} 5 Multiplication-Sign 10{sup 12} g cm{sup -2} ({approx_equal}50 m inside the neutron star), which is just below the ignition depth of superbursts. The required heat generation in the layers on top would be {approx_equal}0.06-0.13 MeV per accreted nucleon. The magnitude and depth rule out electron captures and nuclear fusion reactions as the heat source, but it may be accounted for by chemical separation of light and heavy nuclei. Low-level accretion offers an alternative explanation for the observed variability.

  5. 11 CFR 110.13 - Candidate debates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... parties may stage candidate debates in accordance with this section and 11 CFR 114.4(f). (2) Broadcasters... periodical publications may stage candidate debates in accordance with this section and 11 CFR 114.4(f... candidate debates in accordance with 11 CFR part 100, subparts B and C and part 100, subparts D and E....

  6. Teacher Candidate Dispositions: Perspectives of Professional Expectations

    ERIC Educational Resources Information Center

    Wake, Donna; Bunn, Gary

    2016-01-01

    This study describes a programmatic effort to examine dispositions perceptions of teacher candidates entering the profession. Study participants included 114 master's level teaching candidates in their first semester of a nontraditional teacher education program. Teacher candidates scored themselves on a department disposition rubric designed to…

  7. 11 CFR 9002.2 - Candidate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Candidate. 9002.2 Section 9002.2 Federal Elections FEDERAL ELECTION COMMISSION PRESIDENTIAL ELECTION CAMPAIGN FUND: GENERAL ELECTION FINANCING DEFINITIONS § 9002.2 Candidate. (a) For the purposes of this subchapter, candidate means with respect to any presidential election, an individual who—...

  8. Lutetium +: A better clock candidate

    NASA Astrophysics Data System (ADS)

    Arnold, Kyle; Paez, Eduardo; Haciyev, Elnur; Arifin, Arifin; Cazan, Radu; Barrett, Murray

    2015-05-01

    With the extreme precision now reached by optical clocks it is reasonable to consider redefinition of the frequency standard. In doing so it is important to look beyond the current best-case efforts and have an eye on future possibilities. We will argue that singly ionized Lutetium is a strong candidate for the next generation of optical frequency standards. Lu + has a particularly narrow optical transition in combination with several advantageous properties for managing systematic uncertainties compared to the other atomic species. We summarize these properties and our specific strategies for managing the uncertainties due to external perturbations. Finally, we present the status of our ongoing experiments with trapped Lu +, including the results of precision measurements of its atomic structure.

  9. Photometric monitoring of polar candidates

    NASA Astrophysics Data System (ADS)

    Gabdeev, M. M.

    2015-10-01

    We present photometric observations of two polar candidates, IPHAS J052832.69+283837.6 and 1RXS J073346.0+261933. Both objects reveal brightness variations related to the orbital period with an amplitude of about 1m, and about 0ṃ5 on the long-termscale. The object IPHASJ052832.69+283837.6 also exhibits variations of color indices and light curve shape. Long-term observations allowed us to determine the orbital period of the first system and refine the orbital period of the second system, which proved to be {P_{ord}} = 0_.^d055593(4) and {P_{ord}} = 0_.^d139095(2) respectively. The photometric data analysis proves that these systems are polars.

  10. Asteroid candidates for mass determination

    NASA Astrophysics Data System (ADS)

    Galád, A.

    2001-04-01

    The first 9511 numbered asteroids are studied in terms of their mutual closest approaches and encounter velocities during the period from November 6, 1967, to September 13, 2023. Several large asteroids (diameter 200 km and above) were (will be) encountered by smaller counterparts within a distance of 0.0200 AU. Thus, they are possible candidates for mass determination by the astrometrical method. Similarly, the search for effective perturbers is extended to even smaller asteroids for the much closer separation distance of 0.0020 AU and below. Only the simplified method for evaluation of observable effects on a perturbed body is used. Asteroid masses alone are not computed here. But a stronger criterion to reveal pairs for this purpose in comparison to some specially devoted papers should compensate for the difference and act as a reliable test. The best candidates for mass determination at present are asteroids (1), (2), (4), (10), (11), (24), (52) and (65). This list may be extended by at least (29) in the next 5 years and by many others in the next two decades. Several other strong perturbers from the last three decades are not included in the list, while there is still only a limited number of (or no) precise and reliable observations of perturbed asteroids before a close encounter. It seems that a perturbation by (10) is at least as effective as that by (2) and could be included in asteroid orbit determination in the future. Except for their bulk density determinations (knowing the size), the masses of perturbers could occasionally be used to improve the precision of the computed orbit for perturbed large-numbered and unnumbered asteroids as well.

  11. Phase Diagram of HgTe -ZnTe Pseudobinary and Density, Heat Capacity, and Enthalphy of Mixing of Hg(sub 1-x)Zn(sub x)Te Pseudobinary Melts

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Sha, Yi-Gao; Mazuruk, K.; Lehoczky, S. L.

    1996-01-01

    In this article, the solidus temperatures of the Hg(sub 1-x) Zn(sub x)Te pseudobinary phase diagram for several compositions in the low x region were measured by differential thermal analysis and the HgTe-ZnTe pseudobinary phase diagram was constructed. The densities of two HgZnTe melts, x = 0.10 and 0.16, were determined by an in situ pycnometric technique in a transparent furnace over, respectively, 110 and 50 C ranges of temperature. The thermodynamic properties of the melts, such as the heat capacity and enthalpy of mixing, were calculated for temperatures between the liquidus and 1500 C by assuming an associated solution model for the liquid phase.

  12. Defect structure of Cd{sub x}Hg{sub 1-x}Te films grown by liquid-phase epitaxy, studied by means of low-energy ion treatment

    SciTech Connect

    Izhnin, I. I. Izhnin, A. I.; Fitsych, E. I.; Smirnova, N. A.; Denisov, I. A.; Pociask, M.; Mynbaev, K. D.

    2011-09-15

    Treatment with low-energy ions and measurements of electrical parameters of samples have been used to study the defect structure of Cd{sub x}Hg{sub 1-x}Te films grown by liquid-phase epitaxy. The films contain neutral defects supposedly associated with tellurium nanoinclusions. Ion treatment electrically activates these defects, with a high concentration of donor centers ({approx}10{sup 17} cm{sup -3}) created in the films. These defects decompose in {approx}10{sup 3} min of aging at room temperature. Then the properties of the material are determined by the concentration of residual donors, which is found to be very low (down to {approx}10{sup 14} cm{sup -3}) for the films under study.

  13. Homo- and heterovalent substitutions in the new clathrates I Si30P16Te(8-x)Se(x) and Si(30+x)P(16-x)Te(8-x)Br(x): synthesis, crystal structure, and thermoelectric properties.

    PubMed

    Abramchuk, Nikolay S; Carrillo-Cabrera, Wilder; Veremchuk, Igor; Oeschler, Niels; Olenev, Andrei V; Prots, Yurii; Burkhardt, Ulrich; Dikarev, Evgeny V; Grin, Juri; Shevelkov, Andrei V

    2012-11-01

    The new cationic clathrates I Si(30)P(16)Te(8-x)Se(x) and Si(30+x)P(16-x)Te(8-x)Br(x) were synthesized by the standard ampule technique. The Si(30)P(16)Te(8-x)Se(x) (x = 0-2.3) clathrates crystallize in the cubic space group Pm3̅n with the unit cell parameter a ranging from 9.9382(2) to 9.9696(1) Å. In the case of the Si(30+x)P(16-x)Te(8-x)Br(x) (x = 1-6.4) clathrates, the lattice parameter varies from 9.9720(8) to 10.0405(1) Å; at lower Si/P ratios (x = 1-3) the ordering of bromine atoms induces the splitting of the guest positions and causes the transformation from the space group Pm3n to Pm3. Irrespective of the structure peculiarities, the normal temperature motion of the guest atoms inside the oversized cages of the framework is observed. The title clathrates possess very low thermal expansion coefficients ranging from 6.6 × 10(-6) to 1.0 × 10(-5) K(-1) in the temperature range of 298-1100 K. The characteristic Debye temperature is about 490 K. Measurements of the electrical resistivity and thermopower showed typical behavior of p-type thermally activated semiconductors, whereas the temperature behavior of the thermal conductivity is glasslike and in general consistent with the PGEC concept. The highest value of the thermoelectric figure of merit (ZT = 0.1) was achieved for the Br-bearing clathrate Si(32.1(2))P(13.9(2))Te(6.6(2))Br(1.0(1)) at 750 K. PMID:23072375

  14. 11 CFR 110.13 - Candidate debates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... political parties may stage candidate debates in accordance with this section and 11 CFR 114.4(f). (2... CFR 114.4(f), provided that they are not owned or controlled by a political party, political committee... also cover or carry candidate debates in accordance with 11 CFR part 100, subparts B and C and part...

  15. 11 CFR 110.13 - Candidate debates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... political parties may stage candidate debates in accordance with this section and 11 CFR 114.4(f). (2... CFR 114.4(f), provided that they are not owned or controlled by a political party, political committee... also cover or carry candidate debates in accordance with 11 CFR part 100, subparts B and C and part...

  16. 11 CFR 110.13 - Candidate debates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... political parties may stage candidate debates in accordance with this section and 11 CFR 114.4(f). (2... CFR 114.4(f), provided that they are not owned or controlled by a political party, political committee... also cover or carry candidate debates in accordance with 11 CFR part 100, subparts B and C and part...

  17. 11 CFR 110.13 - Candidate debates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Candidate debates. 110.13 Section 110.13 Federal Elections FEDERAL ELECTION COMMISSION GENERAL CONTRIBUTION AND EXPENDITURE LIMITATIONS AND PROHIBITIONS § 110.13 Candidate debates. (a) Staging organizations. (1) Nonprofit organizations described in 26 U.S.C. 501 (c)(3) or (c)(4) and which do...

  18. 47 CFR 73.1942 - Candidate rates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Candidate rates. 73.1942 Section 73.1942 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Rules Applicable to All Broadcast Stations § 73.1942 Candidate rates. (a) Charges for use of...

  19. 47 CFR 76.206 - Candidate rates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Candidate rates. 76.206 Section 76.206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cablecasting § 76.206 Candidate rates. (a) Charges for use of cable...

  20. 47 CFR 76.206 - Candidate rates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Candidate rates. 76.206 Section 76.206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cablecasting § 76.206 Candidate rates. (a) Charges for use of cable...

  1. 47 CFR 76.206 - Candidate rates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Candidate rates. 76.206 Section 76.206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cablecasting § 76.206 Candidate rates. (a) Charges for use of cable...

  2. 47 CFR 76.206 - Candidate rates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Candidate rates. 76.206 Section 76.206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cablecasting § 76.206 Candidate rates. (a) Charges for use of cable...

  3. 47 CFR 76.206 - Candidate rates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Candidate rates. 76.206 Section 76.206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cablecasting § 76.206 Candidate rates. (a) Charges for use of cable...

  4. Portfolio Development for Teacher Candidates. ERIC Digest.

    ERIC Educational Resources Information Center

    Takona, James P.

    This Digest is intended to help teacher candidates systematically gauge their progress toward the teaching profession by developing a portfolio. Portfolios are one way to assess teacher candidates, and they are a major requirement for experienced teachers seeking board certification from the National Board for Professional Teaching Standards. The…

  5. Critical Thinking Tendencies among Teacher Candidates

    ERIC Educational Resources Information Center

    Genc, Salih Zeki

    2008-01-01

    The study aims to determine critical thinking tendencies among teacher candidates. 720 students from primary school teaching department (Primary School Teaching Programme, Science Teaching Programme and Pre-School Teaching Programme) form the sample of the study. When the gender and age distributions were investigated, 253 candidates are males and…

  6. Special Education Teacher Candidate Assessment: A Review

    ERIC Educational Resources Information Center

    McCall, Zach; McHatton, Patricia Alvarez; Shealey, Monika Williams

    2014-01-01

    Teacher preparation has been under intense scrutiny in recent years. In order for preparation of special education teacher candidates to remain viable, candidate assessment practices must apply practices identified in the extant literature base, while special education teacher education researchers must extend this base with rigorous efforts to…

  7. New supernova remnant candidates in M 31.

    NASA Astrophysics Data System (ADS)

    Magnier, E. A.; Prins, S.; van Paradijs, J.; Lewin, W. H. G.; Supper, R.; Hasinger, G.; Pietsch, W.; Truemper, J.

    1995-12-01

    We have performed a CCD Hα, [SII], V survey of ~1.0 square degree of the disk of M 31 to search for new supernova remnant (SNR) candidates. We have identified candidates based on a combination of criteria: optical line-flux ratios, the presence or absence of ionizing blue stars, and optical morphology. We have identified a total of 178 candidate SNRs, divided into three confidence categories: 13 with the highest confidence, 54 with moderate confidence, and 111 with the lowest confidence. We have also identified 14 large structures with the characteristics of the superbubbles seen in the Galaxy and Magellanic Clouds. Of our 178 candidates, 15 have been identified in previous searches (Braun & Walterbos 1993; Blair et al. 1981; D'Odorico et al. 1980). We present finding charts of all candidate SNRs and the superbubbles we have noted. We also present a detailed discussion of SNR searches in the Local Group.

  8. Undercover Stars Among Exoplanet Candidates

    NASA Astrophysics Data System (ADS)

    2005-03-01

    events by monitoring the brightness of a very large number of stars over extended time intervals. During the past years, it has also included a search for periodic, very shallow "dips" in the brightness of stars, caused by the regular transit of small orbiting objects (small stars, brown dwarfs [2] or Jupiter-size planets). The OGLE team has since announced 177 "planetary transit candidates" from their survey of several hundred thousand stars in three southern sky fields, one in the direction of the Galactic Centre, another within the Carina constellation and the third within the Centaurus/Musca constellations. The nature of the transiting object can however only be established by subsequent radial-velocity observations of the parent star. The size of the velocity variations (the amplitude) is directly related to the mass of the companion object and therefore allows discrimination between stars and planets as the cause of the observed brightness "dip". A Bonanza of Low-Mass Stars An international team of astronomers [3] has made use of the 8.2-m VLT Kueyen telescope for this work. Profiting from the multiplex capacity of the FLAMES/UVES facility that permits to obtain high-resolution spectra of up to 8 objects simultaneously, they have looked at 60 OGLE transit candidate stars, measuring their radial velocities with an accuracy of about 50 m/s [4]. This ambitious programme has so far resulted in the discovery of five new transiting exoplanets (see, e.g., ESO PR 11/04 for the announcement of two of those). Most of the other transit candidates identified by OGLE have turned out to be eclipsing binaries, that is, in most cases common, small and low-mass stars passing in front of a solar-like star. This additional wealth of data on small and light stars is a real bonanza for the astronomers. Constraining the Relation Between Mass and Radius Low-mass stars are exceptionally interesting objects, also because the physical conditions in their interiors have much in common with

  9. Seven Democratic Presidential Candidates Debate Educational Issues.

    ERIC Educational Resources Information Center

    Equity and Excellence, 1988

    1988-01-01

    Provides the transcript of a debate on educational issues among Democratic presidential candidates Paul Simon, Albert Gore, Joseph Biden, Jesse Jackson, Bruce Babbitt, Richard Gephart, and Michael Dukakis. (BJV)

  10. Triton stellar occultation candidates - 1992-1994

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. T.

    1992-01-01

    A search for Triton stellar occultation candidates for the period 1992-1994 has been completed with CCD strip-scanning observations. The search reached an R magnitude of about 17.4 and found 129 candidates within 1.5 arcsec of Triton's ephemeris during this period. Of these events, around 30 occultations are expected to be visible from the earth, indicating that a number of Triton occultation events should be visible from major observatories. Even the faintest of the present candidate events could produce useful occultation data if observed with a large enough telescope. The present astrometric accuracy is inadequate to identify which of these appulse events will produce occultations on the earth; further astrometry is needed to refine the predictions for positive occultation identification. To aid in selecting candidates for additional astrometric and photometric studies, finder charts and earth-based visibility charts for each event are included.

  11. 29 CFR 452.28 - Unopposed candidates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... officers or delegates that would otherwise be required by the Act to be held by secret ballot need not be held by secret ballot when all candidates are unopposed and the following conditions are met: (a)...

  12. Updated candidate list for engineered barrier materials

    SciTech Connect

    McCright, R.D.

    1995-10-01

    This report describes candidate materials to be evaluated over the next several years during advanced design phases for the waste package to be used for the underground disposal of high-level radioactive wastes at the Yucca Mountain facility.

  13. SALT Classification of DES Supernova Candidates

    NASA Astrophysics Data System (ADS)

    Kasai, E.; Bassett, B.; Crawford, S.; Smith, M.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Scolnic, D.; Covarrubias, R. A.; Brout, D. J.; Fischer, J. A.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; D'Andrea, C.; Nichol, R.; Papadopoulos, A.; Sullivan, M.; Maartens, R.

    2015-02-01

    We report optical spectroscopy of a supernova candidates discovered by the Dark Energy Survey. The spectra (400-850 nm) were obtained using the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT).

  14. Candidate preferences and expectations of election outcomes

    PubMed Central

    Delavande, Adeline; Manski, Charles F.

    2012-01-01

    Analysis of data from the American Life Panel shows that in the presidential election of 2008 and in multiple statewide elections in 2010, citizens exhibited large differences in their expectations of election outcomes. Expectations were strongly positively associated with candidate preferences, persons tending to believe that their preferred candidate is more likely to win the election. Committed supporters of opposing candidates regularly differed by 20–30% in their assessments of the likelihood that each candidate would win. These findings contribute evidence on the false consensus effect, the empirical regularity that own preferences tend to be positively associated with perceptions of social preferences. We used unique measures of preferences and perceptions that enabled respondents to express uncertainty flexibly. We studied a setting that would a priori seem inhospitable to false consensus—one where persons have little private information on social preferences but substantial common knowledge provided by media reports of election polls. PMID:22355121

  15. Candidates for GRL North American coeditor sought

    NASA Astrophysics Data System (ADS)

    Geophysical Research Letters (GRL), AGU's all-Union primary research journal, is seeking candidates and nominations for candidates to succeed Rob Van der Voo, whose term as North American Coeditor ends December 31, 1986. The successful candidate will be challenged to seek out interesting papers at the forefront of the geophysical sciences and to attempt to strike a balance in the publication of that science that is of interest to the entire AGU membership. While complementing the interests of Editor in Chief Alex Dessler, the successful candidate will also be challenged to maintain rapid publication time and minimize the publication of research that is routine. The North American Coeditor should be prepared to welcome controversial research papers that challenge conventional wisdom in all fields of interest to AGU. The individual selected for this prestigious position will have a vital role in making GRL an even more important and more exciting journal that readers look forward to receiving each month.

  16. Towards Treating Chemistry Teacher Candidates as Human

    NASA Astrophysics Data System (ADS)

    Lewthwaite, Brian Ellis

    2008-05-01

    This research inquiry investigates the factors influencing chemistry teacher candidates’ development during their extended practica in the second and final year of an After-Degree Bachelor of Education at a university in central Canada. A variety of data sources are used to identify the risk and protective factors impeding and contributing to the achievement of their chemistry pedagogical aspirations. Two theoretical frameworks, both having their origins in the pioneering work of Kurt Lewin, are used to conceptualize how a complex amalgam of personal attribute and environmental factors and the interplay among these factors influence teacher candidate developmental trajectories. The tenets of both Bronfenbrenner’s bioecological model and Learning Environment research provide insights into how the factors influencing teacher candidate development can be understood and systematically documented to provide a template for reflective consideration of the practicum experience for both teacher candidates and those involved in fostering the development of chemistry teacher candidates.

  17. Vaccine candidates for malaria: what's new?

    PubMed

    Takashima, Eizo; Morita, Masayuki; Tsuboi, Takafumi

    2016-01-01

    Although it is more than a decade since the parasite genome information was obtained, standardized novel genome-wide selection/prioritization strategies for candidacy of malaria vaccine antigens are still sought. In the quest to systematically identify candidates, it is impossible to overemphasize the usefulness of wheat germ cell-free technology in expressing quality proteins for the post-genome vaccine candidate discovery. PMID:26559316

  18. A New Way to Confirm Planet Candidates

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    What was the big deal behind the Kepler news conference yesterday? Its not just that the number of confirmed planets found by Kepler has more than doubled (though thats certainly exciting news!). Whats especially interesting is the way in which these new planets were confirmed.Number of planet discoveries by year since 1995, including previous non-Kepler discoveries (blue), previous Kepler discoveries (light blue) and the newly validated Kepler planets (orange). [NASA Ames/W. Stenzel; Princeton University/T. Morton]No Need for Follow-UpBefore Kepler, the way we confirmed planet candidates was with follow-up observations. The candidate could be validated either by directly imaging (which is rare) or obtaining a large number radial-velocity measurements of the wobble of the planets host star due to the planets orbit. But once Kepler started producing planet candidates, these approaches to validation became less feasible. A lot of Kepler candidates are small and orbit faint stars, making follow-up observations difficult or impossible.This problem is what inspired the development of whats known as probabilistic validation, an analysis technique that involves assessing the likelihood that the candidates signal is caused by various false-positive scenarios. Using this technique allows astronomers to estimate the likelihood of a candidate signal being a true planet detection; if that likelihood is high enough, the planet candidate can be confirmed without the need for follow-up observations.A breakdown of the catalog of Kepler Objects of Interest. Just over half had previously been identified as false positives or confirmed as candidates. 1284 are newly validated, and another 455 have FPP of1090%. [Morton et al. 2016]Probabilistic validation has been used in the past to confirm individual planet candidates in Kepler data, but now Timothy Morton (Princeton University) and collaborators have taken this to a new level: they developed the first code thats designed to do fully

  19. Spectroscopy of Kepler Candidate Exoplanet Host Stars

    NASA Astrophysics Data System (ADS)

    Everett, Mark E.; Howell, Steve B.; Silva, David R.; Szkody, Paula

    2014-02-01

    Currently the NASA Kepler Mission has identified 3449 exoplanet candidates, one third with estimated radii R_p<2.5R_oplus and orbiting faint (m_Kep>14.5) host stars. The NASA sponsored Kepler Follow-up Program is focusing on small exoplanet candidates (R_p<2.5R_oplus) and those in habitable zone orbits. Planet radii estimates depend on estimates of host star radii. Based on spectra previously obtained at the KPNO Mayall 4-m for 220 stars with candidate exoplanets, Everett et al. (2013) have shown that many host stars are larger than originally assumed (up to factor of 2). Therefore, the exoplanet candidates they host must be larger than originally assumed, which conversely reduces the number of known Earth- sized exoplanet candidates. Determination of the frequency of such Earth-sized planets is a cornerstone Kepler mission objective and of keen general interest. These Mayall spectra were also used to confirm the Buchhave et al. (2012) result that exoplanet candidates larger than 4R_oplus in short-period orbits are preferentially associated with host stars with solar or higher metallicity, using a fainter and larger sample of stars than Buchhave et al. In short, followup Mayall optical spectroscopy is critical to confirming the detection of Earth-sized exoplanets, a Kepler cornerstone goal, as well as characterizing the relationship between host star properties and planetary system properties. Here, we propose to continue our reconnaissance survey with a focus on the smallest (most rare) exoplanet candidates orbiting the faintest Kepler host stars.

  20. Jellyfish Galaxy Candidates at Low Redshift

    NASA Astrophysics Data System (ADS)

    Poggianti, B. M.; Fasano, G.; Omizzolo, A.; Gullieuszik, M.; Bettoni, D.; Moretti, A.; Paccagnella, A.; Jaffé, Y. L.; Vulcani, B.; Fritz, J.; Couch, W.; D'Onofrio, M.

    2016-03-01

    Galaxies that are being stripped of their gas can sometimes be recognized from their optical appearance. Extreme examples of stripped galaxies are the so-called “jellyfish galaxies” that exhibit tentacles of debris material with a characteristic jellyfish morphology. We have conducted the first systematic search for galaxies that are being stripped of their gas at low-z (z = 0.04-0.07) in different environments, selecting galaxies with varying degrees of morphological evidence for stripping. We have visually inspected B- and V-band images and identified 344 candidates in 71 galaxy clusters of the OMEGAWINGS+WINGS sample and 75 candidates in groups and lower mass structures in the PM2GC sample. We present the atlas of stripping candidates and a first analysis of their environment and their basic properties, such as morphologies, star formation rates and galaxy stellar masses. Candidates are found in all clusters and at all clustercentric radii, and their number does not correlate with the cluster velocity dispersion σ or X-ray luminosity LX. Interestingly, convincing cases of candidates are also found in groups and lower mass halos (1011-1014M⊙), although the physical mechanism at work needs to be securely identified. All the candidates are disky, have stellar masses ranging from log M/M⊙ < 9 to > 11.5 and the majority of them form stars at a rate that is on average a factor of 2 higher (2.5σ) compared to non-stripped galaxies of similar mass. The few post-starburst and passive candidates have weak stripping evidence. We conclude that disturbed morphologies suggestive of stripping phenomena are ubiquitous in clusters and could be present even in groups and low mass halos. Further studies will reveal the physics of the gas stripping and clarify the mechanisms at work.

  1. CANDID: A flexible method for prioritizing candidate genes for complex human traits

    PubMed Central

    Hutz, Janna E.; Kraja, Aldi T.; McLeod, Howard L.; Province, Michael A.

    2015-01-01

    Genomewide studies and localized candidate gene approaches have become everyday study designs for identifying polymorphisms in genes that influence complex human traits. Yet, in general, the number of significant findings and the need to focus in smaller regions require a prioritization of genes for further study. Some candidate gene identification algorithms have been proposed in recent years to attempt to streamline this prioritization, but many suffer from limitations imposed by the source data or are difficult to use and understand. CANDID is a prioritization algorithm designed to produce impartial, accurate rankings of candidate genes that influence complex human traits. CANDID can use information from publications, protein domain descriptions, cross-species conservation measures, gene expression profiles, and protein-protein interactions in its analysis. Additionally, users may supplement these data sources with results from linkage, association and other studies. CANDID was tested on well-known complex trait genes using data from the Online Mendelian Inheritance in Man (OMIM) database. Additionally, CANDID was evaluated in a modeled gene discovery environment, where it ranked genes whose trait associations were published after CANDID’s databases were compiled. In all settings, CANDID exhibited high sensitivity and specificity, indicating an improvement upon previously published algorithms. Its accuracy and ease of use make CANDID a highly useful tool in study design and analysis for complex human traits. PMID:18613097

  2. A PROPELLER-EFFECT INTERPRETATION OF MAXI/GSC LIGHT CURVES OF 4U 1608-52 AND Aql X-1 AND APPLICATION TO XTE J1701-462

    SciTech Connect

    Asai, K.; Matsuoka, M.; Mihara, T.; Sugizaki, M.; Serino, M.; Nakahira, S.; Negoro, H.; Ueda, Y.; Yamaoka, K.

    2013-08-20

    We present the luminosity dwell-time distributions during the hard states of two low-mass X-ray binaries containing a neutron star (NS), 4U 1608-52 and Aql X-1, observed with MAXI/GSC. The luminosity distributions show a steep cutoff on the low-luminosity side at {approx}1.0 Multiplication-Sign 10{sup 36} erg s{sup -1} in both sources. The cutoff implies a rapid luminosity decrease in their outburst decay phases and this decrease can be interpreted as being due to the propeller effect. We estimate the surface magnetic field of 4U 1608-52 to be (0.5-1.6) Multiplication-Sign 10{sup 8} G and Aql X-1 to be (0.6-1.9) Multiplication-Sign 10{sup 8} G from the cutoff luminosity and apply the same propeller mechanism to the similar rapid luminosity decrease observed in the transient Z source, XTE J1701-462, with RXTE/ASM. Assuming that the spin period of the NS is on the order of milliseconds, the observed cutoff luminosity implies a surface magnetic field on the order of 10{sup 9} G.

  3. A Propeller-effect Interpretation of MAXI/GSC Light Curves of 4U 1608-52 and Aql X-1 and Application to XTE J1701-462

    NASA Astrophysics Data System (ADS)

    Asai, K.; Matsuoka, M.; Mihara, T.; Sugizaki, M.; Serino, M.; Nakahira, S.; Negoro, H.; Ueda, Y.; Yamaoka, K.

    2013-08-01

    We present the luminosity dwell-time distributions during the hard states of two low-mass X-ray binaries containing a neutron star (NS), 4U 1608-52 and Aql X-1, observed with MAXI/GSC. The luminosity distributions show a steep cutoff on the low-luminosity side at ~1.0 × 1036 erg s-1 in both sources. The cutoff implies a rapid luminosity decrease in their outburst decay phases and this decrease can be interpreted as being due to the propeller effect. We estimate the surface magnetic field of 4U 1608-52 to be (0.5-1.6) × 108 G and Aql X-1 to be (0.6-1.9) × 108 G from the cutoff luminosity and apply the same propeller mechanism to the similar rapid luminosity decrease observed in the transient Z source, XTE J1701-462, with RXTE/ASM. Assuming that the spin period of the NS is on the order of milliseconds, the observed cutoff luminosity implies a surface magnetic field on the order of 109 G.

  4. Phenoscape: Identifying Candidate Genes for Evolutionary Phenotypes.

    PubMed

    Edmunds, Richard C; Su, Baofeng; Balhoff, James P; Eames, B Frank; Dahdul, Wasila M; Lapp, Hilmar; Lundberg, John G; Vision, Todd J; Dunham, Rex A; Mabee, Paula M; Westerfield, Monte

    2016-01-01

    Phenotypes resulting from mutations in genetic model organisms can help reveal candidate genes for evolutionarily important phenotypic changes in related taxa. Although testing candidate gene hypotheses experimentally in nonmodel organisms is typically difficult, ontology-driven information systems can help generate testable hypotheses about developmental processes in experimentally tractable organisms. Here, we tested candidate gene hypotheses suggested by expert use of the Phenoscape Knowledgebase, specifically looking for genes that are candidates responsible for evolutionarily interesting phenotypes in the ostariophysan fishes that bear resemblance to mutant phenotypes in zebrafish. For this, we searched ZFIN for genetic perturbations that result in either loss of basihyal element or loss of scales phenotypes, because these are the ancestral phenotypes observed in catfishes (Siluriformes). We tested the identified candidate genes by examining their endogenous expression patterns in the channel catfish, Ictalurus punctatus. The experimental results were consistent with the hypotheses that these features evolved through disruption in developmental pathways at, or upstream of, brpf1 and eda/edar for the ancestral losses of basihyal element and scales, respectively. These results demonstrate that ontological annotations of the phenotypic effects of genetic alterations in model organisms, when aggregated within a knowledgebase, can be used effectively to generate testable, and useful, hypotheses about evolutionary changes in morphology. PMID:26500251

  5. Phenoscape: Identifying Candidate Genes for Evolutionary Phenotypes

    PubMed Central

    Edmunds, Richard C.; Su, Baofeng; Balhoff, James P.; Eames, B. Frank; Dahdul, Wasila M.; Lapp, Hilmar; Lundberg, John G.; Vision, Todd J.; Dunham, Rex A.; Mabee, Paula M.; Westerfield, Monte

    2016-01-01

    Phenotypes resulting from mutations in genetic model organisms can help reveal candidate genes for evolutionarily important phenotypic changes in related taxa. Although testing candidate gene hypotheses experimentally in nonmodel organisms is typically difficult, ontology-driven information systems can help generate testable hypotheses about developmental processes in experimentally tractable organisms. Here, we tested candidate gene hypotheses suggested by expert use of the Phenoscape Knowledgebase, specifically looking for genes that are candidates responsible for evolutionarily interesting phenotypes in the ostariophysan fishes that bear resemblance to mutant phenotypes in zebrafish. For this, we searched ZFIN for genetic perturbations that result in either loss of basihyal element or loss of scales phenotypes, because these are the ancestral phenotypes observed in catfishes (Siluriformes). We tested the identified candidate genes by examining their endogenous expression patterns in the channel catfish, Ictalurus punctatus. The experimental results were consistent with the hypotheses that these features evolved through disruption in developmental pathways at, or upstream of, brpf1 and eda/edar for the ancestral losses of basihyal element and scales, respectively. These results demonstrate that ontological annotations of the phenotypic effects of genetic alterations in model organisms, when aggregated within a knowledgebase, can be used effectively to generate testable, and useful, hypotheses about evolutionary changes in morphology. PMID:26500251

  6. Evaluating Historical Candidate Genes for Schizophrenia

    PubMed Central

    Farrell, Martilias; Werge, Thomas; Sklar, Pamela; Owen, Michael J.; Ophoff, Roel; O’Donovan, Michael; Corvin, Aiden; Cichon, Sven; Sullivan, Patrick F

    2015-01-01

    Prior to the genome-wide association era, candidate gene studies were a major approach in schizophrenia genetics. In this invited review, we consider the current status of 25 historical candidate genes for schizophrenia (e.g., COMT, DISC1, DTNBP1, and NRG1). The initial study for 24 of these genes explicitly evaluated common variant hypotheses about schizophrenia. Our evaluation included a meta-analysis of the candidate gene literature, incorporation of the results of the largest genomic study yet published for schizophrenia, ratings from informed researchers who have published on these genes, and ratings from 24 schizophrenia geneticists. On the basis of current empirical evidence and mostly consensual assessments of informed opinion, it appears that the historical candidate gene literature did not yield clear insights into the genetic basis of schizophrenia. A likely reason why historical candidate gene studies did not achieve their primary aims is inadequate statistical power. However, the considerable efforts embodied in these early studies unquestionably set the stage for current successes in genomic approaches to schizophrenia. PMID:25754081

  7. Evaluating historical candidate genes for schizophrenia.

    PubMed

    Farrell, M S; Werge, T; Sklar, P; Owen, M J; Ophoff, R A; O'Donovan, M C; Corvin, A; Cichon, S; Sullivan, P F

    2015-05-01

    Prior to the genome-wide association era, candidate gene studies were a major approach in schizophrenia genetics. In this invited review, we consider the current status of 25 historical candidate genes for schizophrenia (for example, COMT, DISC1, DTNBP1 and NRG1). The initial study for 24 of these genes explicitly evaluated common variant hypotheses about schizophrenia. Our evaluation included a meta-analysis of the candidate gene literature, incorporation of the results of the largest genomic study yet published for schizophrenia, ratings from informed researchers who have published on these genes, and ratings from 24 schizophrenia geneticists. On the basis of current empirical evidence and mostly consensual assessments of informed opinion, it appears that the historical candidate gene literature did not yield clear insights into the genetic basis of schizophrenia. A likely reason why historical candidate gene studies did not achieve their primary aims is inadequate statistical power. However, the considerable efforts embodied in these early studies unquestionably set the stage for current successes in genomic approaches to schizophrenia. PMID:25754081

  8. SOPHIE velocimetry of Kepler transit candidates

    NASA Astrophysics Data System (ADS)

    Santerne, A.; Moutou, C.; Bouchy, F.; Hébrard, G.; Deleuil, M.; Díaz, R. F.; Bonomo, A. S.; Almenara, J.-M.

    2011-10-01

    As CoRoT, the Kepler space mission found a large amount of planetary transit candidates for which radial velocity follow-up is necessary in order to establish the planetary nature and then, to characterize the mass of the transiting companion. We are following up some interesting Kepler candidates with the SOPHIE spectrograph mounted at the 1.93-m telescope in Observatoire de Haute Provence (France). More than one year after the first Kepler release, we will present the strategy used to select the most promising Kepler candidates, within reach of a detection with SOPHIE, using the experience of more than 4 years of CoRoT, SWASP and HAT radial velocity follow-up. We will also highlight the results of the first year of observations that led to the discovery of several new transiting exoplanets and help the understanding of the false positive rate of the Kepler mission.

  9. Developing Potential Candidates of Preclinical Preeclampsia

    PubMed Central

    Founds, Sandra; Zeng, Xuemei; Lykins, David; Roberts, James M.

    2015-01-01

    The potential for developing molecules of interest in preclinical preeclampsia from candidate genes that were discovered on gene expression microarray analysis has been challenged by limited access to additional first trimester trophoblast and decidual tissues. The question of whether these candidates encode secreted proteins that may be detected in maternal circulation early in pregnancy has been investigated using various proteomic methods. Pilot studies utilizing mass spectrometry based proteomic assays, along with enzyme linked immunosorbent assays (ELISAs), and Western immunoblotting in first trimester samples are reported. The novel targeted mass spectrometry methods led to robust multiple reaction monitoring assays. Despite detection of several candidates in early gestation, challenges persist. Future antibody-based studies may lead to a novel multiplex protein panel for screening or detection to prevent or mitigate preeclampsia. PMID:26580600

  10. The Angstrom Project: a new microlensing candidate

    NASA Astrophysics Data System (ADS)

    Kerins, E.; Darnley, M. J.; Newsam, A. M.; Duke, J. P.; Gould, A.; Street, C. Han B.-G. Park R. A.

    2008-12-01

    We report the discovery of a new microlensing candidate in M31 by the Angstrom Project M31 bulge microlensing survey using the Liverpool Telescope (La Palma). The candidate was discovered using difference imaging techniques by the Angstrom Project Alert System (APAS) in a series of Sloan i'-band images of the bulge of M31.

  11. Illustrations of Engagement Styles: Four Teacher Candidates

    ERIC Educational Resources Information Center

    Guerra, Norma S.

    2009-01-01

    The inherent complexity of preparing future teachers and the associated high stakes upon graduation continue to motivate educators to examine how best to engage teacher candidates as students so that they will be skilled and adaptable once they become teachers. To this end, a new conceptualization of engagement styles is presented and illustrated…

  12. Emotional Intelligence and Beginning Teacher Candidates

    ERIC Educational Resources Information Center

    Justice, Madeline; Espinoza, Sue

    2007-01-01

    According to the Bureau of Labor Statistics, Texas will need over 82,000 new teachers by 2008. Many teachers are leaving the profession within 5 years of being employed. Closing a revolving door, teacher preparation programs are discussing this phenomenon. One hundred sixty beginning teacher candidates were surveyed using the Emotional Skills…

  13. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On the grounds of the Kennedy Space Center, members of the 1998 astronaut candidate class (Group 17) watch as candidate Clayton C. Anderson practices using firefighting equipment during fire training. The class is at KSC for training activities, including a flight awareness program, plus touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The other U.S. candidates in the '98 class are Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  14. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On the grounds of the Kennedy Space Center, members of the 1998 astronaut candidate class (Group 17) watch as candidate Tracy E. Caldwell (Ph.D.) practices using firefighting equipment during fire training. The class is at KSC for training activities, including a flight awareness program, plus touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The other U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  15. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On the grounds of the Kennedy Space Center, members of the 1998 astronaut candidate class (Group 17) watch as candidate Sunita L. Williams practices using firefighting equipment during fire training. The class is at KSC for training activities, including a flight awareness program, plus touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The other U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  16. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On the grounds of the Kennedy Space Center, members of the 1998 astronaut candidate class (Group 17) watch as candidate Patricia C. Hilliard (M.D.) practices using firefighting equipment during fire training. The class is at KSC for training activities, including a flight awareness program, plus touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The other U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  17. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On the grounds of the Kennedy Space Center, members of the 1998 astronaut candidate class (Group 17) watch as candidate Alan G. Poindexter practices using firefighting equipment during fire training. The class is at KSC for training activities, including a flight awareness program, plus touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The other U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  18. Social Justice Perceptions of Teacher Candidates

    ERIC Educational Resources Information Center

    Turhan, Muhammed

    2010-01-01

    This study aims to determine the social justice perceptions of teacher candidates being trained in an education faculty. For this purpose, national and international literature was reviewed by the researcher and a 32-item questionnaire was developed and implemented on 237 senior year education faculty students. Data from the questionnaires were…

  19. Electronic Portfolio Adoption for Teacher Education Candidates

    ERIC Educational Resources Information Center

    Ledoux, Michael W.; McHenry, Nadine

    2006-01-01

    Programs of professional development for preservice teachers of young children in the United States attempt to align their program goals and candidate performances to The National Association for the Education of Young Children (NAEYC), Association of Childhood Education International (ACEI), and their particular state standards. In addition they…

  20. 76 FR 36130 - Call for Candidates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-21

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Call for Candidates AGENCY: Federal Accounting Standards Advisory Board. ACTION: Request for... Accounting Standards Advisory Board (FASAB or the Board) with the requested materials in response to...

  1. FAME's Search for Extrasolar Planet Candidates

    NASA Astrophysics Data System (ADS)

    Johnston, K.

    FAME is a five year survey mission to observe the positions, proper motions, and parallaxes of 40,000,000 stars down to 15th magnitude with accuracies of 50 microarcseconds at 9th magnitude. In addition to producing an astrometric and photometric catalog unparalleled for its accuracy and size, the survey will provide significant astrophysics results and search for extrasolar planet candidates.

  2. Query by image example: The CANDID approach

    SciTech Connect

    Kelly, P.M.; Cannon, M.; Hush, D.R.

    1995-02-01

    CANDID (Comparison Algorithm for Navigating Digital Image Databases) was developed to enable content-based retrieval of digital imagery from large databases using a query-by-example methodology. A user provides an example image to the system, and images in the database that are similar to that example are retrieved. The development of CANDID was inspired by the N-gram approach to document fingerprinting, where a ``global signature`` is computed for every document in a database and these signatures are compared to one another to determine the similarity between any two documents. CANDID computes a global signature for every image in a database, where the signature is derived from various image features such as localized texture, shape, or color information. A distance between probability density functions of feature vectors is then used to compare signatures. In this paper, the authors present CANDID and highlight two results from their current research: subtracting a ``background`` signature from every signature in a database in an attempt to improve system performance when using inner-product similarity measures, and visualizing the contribution of individual pixels in the matching process. These ideas are applicable to any histogram-based comparison technique.

  3. 47 CFR 73.1942 - Candidate rates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., or election, to such office shall not exceed: (1) During the 45 days preceding the date of a primary or primary runoff election and during the 60 days preceding the date of a general or special election... advertising, shall be provided to candidates prior to election day if a station has provided a...

  4. Enhancing Advocacy Skills of Teacher Candidates

    ERIC Educational Resources Information Center

    Holmes, Melissa A.; Herrera, Socorro G.

    2009-01-01

    This case study explores the dynamics of enhancing the capacities of teacher candidates in the Bilingual/Bicultural Education Students Interacting to Obtain Success (BESITOS) recruitment and retention program to advocate for culturally and linguistically diverse (CLD) students. Herrera and Murry's advocacy framework provides the theoretical…

  5. Secondary Teacher Candidates' Lesson Planning Learning

    ERIC Educational Resources Information Center

    Santoyo, Christina; Zhang, Shaoan

    2016-01-01

    Teacher candidates (TCs) use clinical experiences to enact concepts taught in their university courses; therefore field experiences may be the most important component of teacher preparation (Hammerness et al., 2005). TCs require support and guidance as they learn to adapt curriculum materials for effective use in the classroom (Davis, 2006). They…

  6. Modeling Collaboration for ESL Teacher Candidates

    ERIC Educational Resources Information Center

    DelliCarpini, Margo

    2014-01-01

    This article reports on a semester-long project where a TESOL professor and English Education professor modeled collaborative teaching and explicitly taught collaboration skills to a coscheduled teaching methods class consisting of TESOL and Secondary English teacher candidates. Data were collected in the form of pre- and postsemester surveys. In…

  7. Promoting Team Leadership Skills in Doctoral Candidates

    ERIC Educational Resources Information Center

    Suleiman, Mahmoud; Whetton, Danny

    2014-01-01

    Doctoral programs can serve as an optimal opportunity for candidates to engage in tasks and activities to transform them and their schools. The paradigm shifts in such preparation involve moving from sitting and getting to making and taking. Most importantly, it requires building leadership skills and styles necessary to bring about desired change…

  8. Towards Treating Chemistry Teacher Candidates as Human

    ERIC Educational Resources Information Center

    Lewthwaite, Brian Ellis

    2008-01-01

    This research inquiry investigates the factors influencing chemistry teacher candidates' development during their extended practica in the second and final year of an After-Degree Bachelor of Education at a university in central Canada. A variety of data sources are used to identify the risk and protective factors impeding and contributing to the…

  9. Gallium-67 imaging in candidal esophagitis

    SciTech Connect

    Rundback, J.H.; Goldfarb, C.R.; Ongseng, F. )

    1990-01-01

    Ga-67 scanning has been used to evaluate esophageal carcinoma. It has demonstrated candidal infection in other body sites and, in one previous case, in the esophagus. The authors present a case of diffuse esophageal uptake of Ga-67 in esophageal candidiasis.

  10. Evaluating Constructivist Beliefs of Teacher Candidates

    ERIC Educational Resources Information Center

    Aldrich, Jennifer E.; Thomas, Kelli R.

    2005-01-01

    Teacher education programs that want their future teachers to embrace and employee constructivist principles must strive to provide opportunities for teacher candidates to develop an understanding of constructivism. The paper presents a structure for embedding constructivist principles into early childhood and elementary teacher education courses…

  11. 11 CFR 9003.2 - Candidate certifications.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... eligible to receive payments under 11 CFR part 9005, each Presidential and Vice Presidential candidate of a... excess of the aggregate payments to which they will be entitled under 11 CFR part 9004. (2) That no... established under 11 CFR 9003.3(a); or except to the extent necessary to make up any deficiency in...

  12. 11 CFR 9003.2 - Candidate certifications.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... eligible to receive payments under 11 CFR part 9005, each Presidential and Vice Presidential candidate of a... excess of the aggregate payments to which they will be entitled under 11 CFR part 9004. (2) That no... established under 11 CFR 9003.3(a); or except to the extent necessary to make up any deficiency in...

  13. 11 CFR 9003.2 - Candidate certifications.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... eligible to receive payments under 11 CFR part 9005, each Presidential and Vice Presidential candidate of a... excess of the aggregate payments to which they will be entitled under 11 CFR part 9004. (2) That no... established under 11 CFR 9003.3(a); or except to the extent necessary to make up any deficiency in...

  14. 11 CFR 9003.2 - Candidate certifications.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... eligible to receive payments under 11 CFR part 9005, each Presidential and Vice Presidential candidate of a... excess of the aggregate payments to which they will be entitled under 11 CFR part 9004. (2) That no... established under 11 CFR 9003.3(a); or except to the extent necessary to make up any deficiency in...

  15. GTC Classification of DES Supernova Candidates

    NASA Astrophysics Data System (ADS)

    Castander, F. J.; Casas, R.; Garcia-Alvarez, D.; Perez-Valladares, D.; Miquel, R.; Smith, M.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Scolnic, D.; Covarrubias, R. A.; Brout, D. J.; Fischer, J. A.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; D'Andrea, C.; Nichol, R.; Papadopoulos, A.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.

    2015-03-01

    We report optical spectroscopy and classification of 3 SN candidates discovered by the Dark Energy Survey. The spectra (490-920 nm) were obtained using OSIRIS on the Gran Telescopio CANARIAS (GTC), and classification was performed using SuperFit (Howell et al. 2005, Ap.J. 634, 1190) and SNID (Blondin & Tonry, 2007, Ap.J., 666, 1024).

  16. ESL Teacher-Candidates' Beliefs about Language

    ERIC Educational Resources Information Center

    Fleming, Douglas; Bangou, Francis; Fellus, Osnat

    2011-01-01

    How do ESL teacher-candidates grapple with beliefs about language during their professional training? In this article, we present the findings of a qualitative research study conducted in a large eastern Canadian university Bachelor of Education program. As Johnson (2010) has recently noted, despite extensive research and theoretical work that…

  17. Automatic Classification of Kepler Planetary Transit Candidates

    NASA Astrophysics Data System (ADS)

    McCauliff, Sean D.; Jenkins, Jon M.; Catanzarite, Joseph; Burke, Christopher J.; Coughlin, Jeffrey L.; Twicken, Joseph D.; Tenenbaum, Peter; Seader, Shawn; Li, Jie; Cote, Miles

    2015-06-01

    In the first three years of operation, the Kepler mission found 3697 planet candidates (PCs) from a set of 18,406 transit-like features detected on more than 200,000 distinct stars. Vetting candidate signals manually by inspecting light curves and other diagnostic information is a labor intensive effort. Additionally, this classification methodology does not yield any information about the quality of PCs; all candidates are as credible as any other. The torrent of exoplanet discoveries will continue after Kepler, because a number of exoplanet surveys will have an even broader search area. This paper presents the application of machine-learning techniques to the classification of the exoplanet transit-like signals present in the Kepler light curve data. Transit-like detections are transformed into a uniform set of real-numbered attributes, the most important of which are described in this paper. Each of the known transit-like detections is assigned a class of PC; astrophysical false positive; or systematic, instrumental noise. We use a random forest algorithm to learn the mapping from attributes to classes on this training set. The random forest algorithm has been used previously to classify variable stars; this is the first time it has been used for exoplanet classification. We are able to achieve an overall error rate of 5.85% and an error rate for classifying exoplanets candidates of 2.81%.

  18. The Responsibility Education of Teacher Candidates

    ERIC Educational Resources Information Center

    Toremen, Fatih

    2011-01-01

    In this study, it was aimed to take the views and suggestions of academicians working at the faculty of education on what can be done about teacher candidates' responsibility education. This study was designed on the basis of qualitative research approach and purposive sampling method was used. Data were collected by unstructured interview method…

  19. Collaboration with Community Partners: Engaging Teacher Candidates

    ERIC Educational Resources Information Center

    Gandy, S. Kay; Pierce, Judy; Smith, Alicia Brooke

    2009-01-01

    Two social studies methods instructors created an assignment that places teacher candidates in leadership roles in partnerships with community organizations to plan and implement projects to increase student learning. This article outlines the project requirements, past project results, and student reflections on the collaborative effort. It…

  20. Measuring Credential Candidates' Impact on Student Achievement

    ERIC Educational Resources Information Center

    Hagans, Kristi S.; Powers, Kristin

    2015-01-01

    The Council for the Accreditation of Educator Preparation (CAEP) requires faculty from educator preparation programs to provide evidence of credential candidates' impact on K-12 student learning. However, there is a paucity of information on preparation programs' use of direct assessments of student learning to gauge credential candidate…

  1. Computer Teacher Candidates' Metaphors about the Internet

    ERIC Educational Resources Information Center

    Saban, Aslihan

    2010-01-01

    The purpose of this study was to examine the metaphors of exit-level Turkish computer teacher candidates about the concept of "internet". Participants included 45 seniors (23 boys and 22 girls) majoring in the Department of Computer and Instructional Technologies at Selcuk University, Ahmet Kelesoglu Faculty of Education. They were asked to…

  2. 32 CFR 901.6 - Candidate fitness test requirement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Candidate fitness test requirement. 901.6... Requirements § 901.6 Candidate fitness test requirement. Before being offered an appointment, candidates must take a Candidate Fitness Test (CFT) which consists of exercises designed to measure muscular...

  3. 32 CFR 901.6 - Candidate fitness test requirement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Candidate fitness test requirement. 901.6... Requirements § 901.6 Candidate fitness test requirement. Before being offered an appointment, candidates must take a Candidate Fitness Test (CFT) which consists of exercises designed to measure muscular...

  4. 32 CFR 901.6 - Candidate fitness test requirement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Candidate fitness test requirement. 901.6... Requirements § 901.6 Candidate fitness test requirement. Before being offered an appointment, candidates must take a Candidate Fitness Test (CFT) which consists of exercises designed to measure muscular...

  5. 32 CFR 901.6 - Candidate fitness test requirement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Candidate fitness test requirement. 901.6... Requirements § 901.6 Candidate fitness test requirement. Before being offered an appointment, candidates must take a Candidate Fitness Test (CFT) which consists of exercises designed to measure muscular...

  6. 32 CFR 901.6 - Candidate fitness test requirement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Candidate fitness test requirement. 901.6... Requirements § 901.6 Candidate fitness test requirement. Before being offered an appointment, candidates must take a Candidate Fitness Test (CFT) which consists of exercises designed to measure muscular...

  7. 22 CFR 11.8 - Travel expenses of candidates.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Travel expenses of candidates. 11.8 Section 11... Travel expenses of candidates. The travel and other personal expenses of candidates incurred in... Department may issue round-trip invitational travel orders to bring candidates to Washington at...

  8. Candidate marketing takes the guessing game out of choosing employers.

    PubMed

    Russell, Judith; Havel, Stacey

    2010-01-01

    Candidate marketing builds a foundation for relationships between employers and potential employees. Additionally, candidate marketing differentiates organizations in the marketplace. Organizations using candidate marketing to communicate the employer brand can expect a higher quality of candidates, and new employees are better prepared for the work environment and culture. Today, organizations can use a variety of integrated tools and techniques to communicate and build relationships with candidates. Candidate marketing demonstrates an organization's willingness towards transparency, and ability to invite open conversations between candidates and members of the organizations. PMID:20672542

  9. Understanding the newly observed heavy pentaquark candidates

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Hai; Wang, Qian; Zhao, Qiang

    2016-06-01

    We find that several thresholds can contribute to the enhancements of the newly observed heavy pentaquark candidates Pc+ (4380) and Pc+ (4450) via the anomalous triangle singularity (ATS) transitions in the specific kinematics of Λb → J / ψK- p. Apart from the observed two peaks we find that another peaks around 4.5 GeV can also be produced by the ATS. We also show that the Σc(*) can be produced at leading order in Λb decay. This process is different from the triangle diagram and its threshold enhancement only appears as CUSP effects if there is no pole structure or the ATS involved. The threshold interaction associated with the presence of the ATS turns out to be a general phenomenon and plays a crucial role in the understanding of candidates for exotic states.

  10. Warm Debris Disk Candidates from WISE

    NASA Technical Reports Server (NTRS)

    Padgett, Deborah; Stapelfeldt, Karl; Liu, Wilson; Leisawitz, David

    2011-01-01

    The Wide Field Infrared Survey Explorer (WISE) has just completed a sensitive all-sky survey in photometric bands at 3.4, 4.6, 12, and 22 microns. We report on a preliminary investigation of main sequence Hipparcos and Tycho catalog stars with 22 micron emission in excess of photospheric levels. This warm excess emission traces material in the circumstellar region likely to host terrestrial planets and is preferentially found in young systems with ages < 1 Gyr. Nearly a hundred new warm debris disk candidates are detected among FGK stars and 150 A stars within 120 pc. We are in the process of obtaining spectra to determine spectral types and activity level of these stars and are using HST, Herschel and Keck to characterize the dust, multiplicity, and substellar companions of these systems. In this contribution, we will discuss source selection methods and individual examples from among the WISE debris disk candidates.

  11. Optical Nova Candidate in M 31

    NASA Astrophysics Data System (ADS)

    Henze, M.; Burwitz, V.; Pietsch, W.; Updike, A.; Milne, P.; Williams, G.; Hartmann, D. H.

    2008-05-01

    We report the discovery of an optical nova candidate in M 31 on two 8x60s stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 May 26.45 and 27.45 UT with respective magnitudes of 17.0 and 17.5. The position for the nova candidate is RA = 00h43m12.08s, Dec = +41d19'15.8" (J2000, accuracy of 0.3"), which is 5'13" east and 3'6" north of the core of M 31.

  12. Optical Nova Candidate in M 31

    NASA Astrophysics Data System (ADS)

    Burwitz, V.; Henze, M.; Pietsch, W.; Updike, A.; Hartmann, D.; Milne, P.; Williams, G.

    2008-01-01

    We report the discovery of an optical nova candidate in M 31 on two 12*60sec stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 Jan 20.21 and 21.21 with respective magnitudes of 17.2 and 17.9. The position for the nova candidate is RA = 00h42m58.54s, Dec = 41d14'44.1" (J2000, accuracy of 0.3"), which is 2'41" west and 1'25 south of the core of M 31.

  13. Optical Nova Candidate in M 31

    NASA Astrophysics Data System (ADS)

    Henze, M.; Burwitz, V.; Pietsch, W.; Updike, A.; Milne, P.; Williams, G.; Hartmann, D. H.

    2008-06-01

    We report the discovery of an optical nova candidate in M 31 on two 11x60s stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 June 14.46 and 16.46 UT with respective magnitudes of 18.0 and 17.7. The position for the nova candidate is RA = 00h42m37.72s, Dec = +41d12'30.0"(J2000, accuracy of 0.3"), which is 1'14" west and 3'39" south of the core of M 31. All magnitudes given are obtained from a photometric solution using R magnitudes of the Local Group Survey M 31 catalogue (Massey et al.

  14. Voltaire's Candide, medical students, and mentoring

    PubMed Central

    Papadimos, Thomas J

    2007-01-01

    In Voltaire's work, Candide, a young, naïve man, who has been taught that humans live in the best of all possible worlds, is thrust into the world only to find that this may not be so. He learns over time to balance his optimism with the skepticism he acquires through experience. While today's medical students are not naïve like the character Candide, they, nonetheless, carry an impression of the ideal medical practice, along with the expectation of a successful medical practice. Good mentors and role models are important to students in order to temper their optimism, control their skepticism, and to help them to be realistic, not only about their expectations of medical practice, but what society expects of them. PMID:17608936

  15. Candidate Species Selection: Cultural and Photosynthetic Aspects

    NASA Technical Reports Server (NTRS)

    Mitchell, C. A.

    1982-01-01

    Cultural information is provided for a data base that will be used to select candidate crop species for a controlled ecological life support system (CELSS). Lists of food crops which will satisfy most nutritional requirements of humans and also fit within the scope of cultural restrictions that logically would apply to a closed, regenerating system were generated. Cultural and environmental conditions that will allow the most rapid production of edible biomass from candidate species in the shortest possible time are identified. Cultivars which are most productive in terms of edible biomass production by (CE) conditions, and which respond to the ever-closed approach to optimization realized by each shortened production cycle are selected. The experimental approach with lettuce was to grow the crop hydroponically in a growth chamber and to manipulate such variables as light level and duration, day/night temperature, and nutrient form and level in the solution culture.

  16. Characterization of a New Hypergolic Fuel Candidate

    NASA Technical Reports Server (NTRS)

    Manzara, Tony

    2000-01-01

    2-(Dimethylamino)ethylazide was identified by Darren Thompson of the US Army Aviation Missile Command (AMCOM) as a promising candidate to replace hydrazine derivatives in certain hypergolic fuel applications, and as a monopropellant using a heated catalyst bed. The preparation of the material has been scaled up to the pilot plant level, and evaluations of its relevant properties have indicated that it may have broader application than was originally foreseen. Physical, chemical, and hazards properties are reported in this paper

  17. Characterization of a New Hypergolic Fuel Candidate

    NASA Technical Reports Server (NTRS)

    Manzara, Tony

    2000-01-01

    2-(Dimethylamino)ethylazide was identified by Darren Thompson of the US Army Aviation Missile Command (AMCOM) as a promising candidate to replace hydrazine derivatives in certain hypergolic fuel applications, and as a monopropellant using a heated catalyst bed. The preparation of the material has been scaled up to the pilot plant level, and evaluations of its relevant properties have indicated that it may have broader application than was originally foreseen. Physical, chemical, and hazardous properties are reported in this paper.

  18. New Young Star Candidates in BRC 27

    NASA Astrophysics Data System (ADS)

    Novatne, Lauren J.; Mattrocce, G.; Milan, T.; Quinonez, A.; Rebull, L. M.; Barge, J.; Amayo, R.; Bieber, H.; Block, L.; Cheung, E.; Cruz, A.; Elkin, D.; Figueroa, A.; Jakus, M.; Kelo, A.; Larson, O.; Lemma, B.; Li, Y.; Loe, C.; Maciag, V.; Moreno, N.; Nevels, M.; Pezanoski-Cohen, G.; Short, M.; Skatchke, K.; Tur-Kaspa, A.; Zegeye, D.; Armstrong, J.; Bonadurer, R.; French, D.; Free, B.; Miller, C.; Scherich, H.; Willis, T.; Koenig, X.; Laher, R.; Padgett, D.; Piper, M.; Pavlak, A.; Piper, M.; Venezio, E.; Ali, B.

    2013-01-01

    All stars originate from clouds of interstellar gas that collapse either under their own gravity or with external help. In triggered star formation, the collapse of a cloud is initiated by pressure, e.g., from nearby star(s). When the external source is bright stars, it can illuminate the rims of the cloud, creating bright-rimmed clouds (BRCs) to be visible at optical and infrared (IR) wavelengths. We searched for new candidate young stellar objects (YSOs) primarily using the March 2012 all-sky release of Wide-field Infrared Survey Explorer (WISE) data in BRC 27, which is part of CMa R1, a region of known star formation. Spitzer data of a 5’x5’ region centered on BRC 27 were presented by Johnson et al. 2012 and Rebull et al. 2012. We investigated WISE data within a 20 arcminute radius of BRC 27 0.35 sq. deg), combining it with Spitzer data serendipitously obtained in this region, 2MASS data, and optical data. We started from nearly 4000 WISE sources and identified about 200 candidate YSOs via a series of color cuts (Koenig et al. 2012) to identify objects with WISE colors consistent with other YSOs, e.g., having an apparent IR excess. There are about 100 objects in this region already identified in the literature as possible YSOs, about 40 of which we recovered with the color cuts. We investigated these literature YSOs and YSO candidates in all available images, and created spectral energy distributions (SEDs) and color-magnitude diagrams for further analysis of each object. We will present an analysis of our selected sub-sample of YSO candidates. This research was made possible through the NASA/IPAC Teacher Archive Research Project (NITARP) and was funded by NASA Astrophysics Data Program and Archive Outreach funds. Our education results are described in a companion education poster, Bonadurer et al.

  19. Optical durability testing of candidate solar mirrors

    SciTech Connect

    Jorgensen, G.; Kennedy, C.; King, D.; Terwilliger, K.

    2000-03-24

    Durability testing of a variety of candidate solar reflector materials at outdoor test sites and in laboratory accelerated weathering chambers is the main activity within the Advanced Materials task of the Concentrated Solar Power (CSP) Program. Outdoor exposure testing (OET) at up to eight outdoor, worldwide exposure sites has been underway for several years. This includes collaboration under the auspices of the International Energy Agency (IEA) Solar Power and Chemical Energy Systems (SolarPACES) agreement. Outdoor sites are fully instrumented in terms of monitoring meteorological conditions and solar irradiance. Candidate materials are optically characterized prior to being subjected to exposure in real and simulated weathering environments. Optical durability is quantified by periodically re-measuring hemispherical and specular reflectance as a function of exposure time. By closely monitoring the site- and time-dependent environmental stress conditions experienced by the material samples, site-dependent loss of performance may be quantified. In addition, accelerated exposure testing (AET) of these materials in parallel under laboratory-controlled conditions may permit correlating the outdoor results with AET, and subsequently predicting service lifetimes. Test results to date for a large number of candidate solar reflector materials are presented in this report. Acronyms are defined. Based upon OET and AET results to date, conclusions can be drawn about the optical durability of the candidate reflector materials. The optical durability of thin glass, thick glass, and two metallized polymers can be characterized as excellent. The all-polymeric construction, several of the aluminized reflectors, and a metallized polymer can be characterized as having intermediate durability and require further improvement, testing and evaluation, or both.

  20. SAO RAS spectral classification of SN candidates

    NASA Astrophysics Data System (ADS)

    Fatkhullin, T. A.; Moskvitin, A. S.

    2016-08-01

    We observed five SN candidates (AT 2016eld, AT 2016eku, MASTER OT J225939.54+020859.6, AT 2016ekw and AT 2016elw) with the BTA/Scorpio-I on the night of August, 2/3. Direct images in the V band and long-slit spectra in the range of 3600-7600AA (resolution FWHM = 10A) were obtained.

  1. Various Approaches for Targeting Quasar Candidates

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Zhao, Y.

    2015-09-01

    With the establishment and development of space-based and ground-based observational facilities, the improvement of scientific output of high-cost facilities is still a hot issue for astronomers. The discovery of new and rare quasars attracts much attention. Different methods to select quasar candidates are in bloom. Among them, some are based on color cuts, some are from multiwavelength data, some rely on variability of quasars, some are based on data mining, and some depend on ensemble methods.

  2. Contamination analysis of SSF candidate materials

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1991-01-01

    NASA's In Situ Contamination Effects Facility, Marshall Space Flight Center, has been used to test several candidate materials for use upon Space Station Freedom. Optical measurements were made in the vacuum ultraviolet (VUV) as test mirrors were contaminated by materials in a space-like environment. This was done to determine the effects of the contamination and subsequent exposure to VUV radiation upon optical components that will be used upon the space station.

  3. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the Orbiter Processing Facility, members of the 1998 astronaut candidate class (group 17) learn about the thermal protection system on the orbiters, such as Atlantis overhead. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  4. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the Orbiter Processing Facility bay 3, members of the 1998 astronaut candidate class (group 17) get a close-up view of the tiles, part of the thermal protection system, on the underside of the orbiter Atlantis overhead. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  5. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Members of the 1998 astronaut candidate class (group 17) look at the aft of a Space Shuttle Main Engine (SSME) (right). The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center, the crew headquarters, as well as the SSME Processing Facility. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  6. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the Space Station Processing Facility, Ron Woods (left) shows members of the 1998 astronaut candidate class (group 17) an Apollo-style space suit and how it differs from the current suits. The class is taking part in training activities, including fire training and a flight awareness program, plus touring the OPF, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center, the crew headquarters, as well as the SSME Processing Facility. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  7. 1998 astronaut candidates tour CCAS facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Cape Canaveral Air Station, members of the 1998 astronaut candidate class (Group 17) pose in front of the Project Mercury monument at Launch Complex 14 during a tour of the station's facilities. This 13-foot-high astronomical symbol for the planet Mercury was constructed by General Dynamics, the Atlas airframe contractor, and dedicated in 1964 in honor of those who flew in the Mercury 7 capsule. The class is at Kennedy Space Center taking part in training activities, including a flight awareness program, as well as touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  8. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the Space Station Processing Facility (SSPF), members of the 1998 astronaut candidate class (group 17) are shown future components of the International Space Station, such as the Multi- Purpose Logistics Module at right. The class is taking part in training activities, including fire training and a flight awareness program, plus touring the OPF, VAB, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, the crew headquarters, as well as the SSPF. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  9. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Members of the 1998 astronaut candidate class (group 17) learn about the use of the Space Shuttle Main Engine (SSME) Processing Facility. At left is one of the main shuttle engines. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center, the crew headquarters, as well as the SSME Processing Facility. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  10. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The 1998 astronaut candidate class (group 17) gather in the Space Shuttle Main Engine Processing (SSMEP) Facility. In the foreground is one of the main shuttle engines. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  11. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On a raised platform in the Orbiter Processing Facility bay 3, members of the 1998 astronaut candidate class (group 17) look at the aft fuselage of the orbiter Atlantis. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  12. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the Orbiter Processing Facility bay 3, Larry Osheim (right), who is with United Space Alliance, shows members of the 1998 astronaut candidate class (group 17) a sample of Felt Reusable Surface Insulation (FRSI) blankets used on the orbiters. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  13. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On the grounds of the Kennedy Space Center, members of the 1998 astronaut candidate class (Group 17) take part in fire training. The class is taking part in training activities, including a flight awareness program, plus touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  14. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On the grounds of the Kennedy Space Center, members of the 1998 astronaut candidate class (Group 17) watch a demonstration as part of fire training. The class is taking part in training activities, including a flight awareness program, plus touring the OPF, VAB, SSPF, SSME Processing Facility, launch pads, SLF, Apollo/Saturn V Center, and the crew quarters. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  15. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    On their tour of KSC, members of the 1998 astronaut candidate class (group 17) stop at the Space Shuttle Main Engine (SSME) Processing Facility for a close up look at a main shuttle engine. The class is taking part in training activities, including fire training and a flight awareness program, plus touring the OPF, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center, the crew headquarters, as well as the SSME Processing Facility. The U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes.

  16. 1998 astronaut candidates tour KSC facilities

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In the Orbiter Processing Facility, 1998 astronaut candidates (ASCAN) Barbara R. Morgan, Patricia C. Hilliard (M.D.) and Bjarni V. Tryggvason look at the hardware exhibits, such as the engine actuator on the table. Tryggvason is with the Canadian Space Agency. The 1998 ASCAN class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters. Other U.S. candidates in the '98 class are Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and the other international candidates are Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, and Marcos Pontes.

  17. WISE Observations of Rendezvous Mission Candidate Comets

    NASA Astrophysics Data System (ADS)

    Lisse, Carey M.; Bauer, J. M.; Fernandez, Y. R.; Mainzer, A. K.; Walker, R. G.; Meech, K. J.; Grav, T.; Weissman, P. R.; Kramer, E.; Stevenson, R.

    2012-10-01

    In 1992, Osip et al. wrote: "Several comet flyby and/or rendezvous missions are currently being planned, for which supporting groundbased data from previous apparitions should prove useful. Here, we discuss groundbased narrowband photometry obtained over the last 15 years for nine candidate comets, five of which have been observed on multiple apparitions -- we derive limits on the size of each cometary nucleus. In order to facilitate spacecraft mission planning, we also present molecular abundance ratios, note variations in cometary activity as a function of orbital position and between apparitions, and note the overall degree of dustiness. A detailed analysis of the characteristics of these nine viable mission candidates will provide necessary information for prioritizing targets for any future missions." In this work, we update Osip et al.'s 1992 work using recent photometric infrared observations of the best candidate comet spacecraft targets observed by WISE and other (IRAS, MSX, ISO, Spitzer) infrared space telescopes. The comets studied include 2P/Encke, 9P/Tempel 1, 10P Tempe1 2, 19P/Borrelly, 22P/Kopff, 67P/Churyumov-Gerasimenko, 81P/Wild, 103P/Hartley 2, 107P/Wilson-Harrington. We present imagery, photometry, and temporal trend data, and derived estimates of the dust mass, spatial distribution, albedo/emissivity, and PSD for each comet.

  18. Uncovering the Nucleus Candidate for NGC 253

    NASA Astrophysics Data System (ADS)

    Günthardt, G. I.; Agüero, M. P.; Camperi, J. A.; Díaz, R. J.; Gomez, P. L.; Bosch, G.; Schirmer, M.

    2015-11-01

    NGC 253 is the nearest spiral galaxy with a nuclear starburst that becomes the best candidate for studying the relationship between starburst and active galactic nucleus activity. However, this central region is veiled by large amounts of dust, and it has been so far unclear which is the true dynamical nucleus to the point that there is no strong evidence that the galaxy harbors a supermassive black hole co-evolving with the starburst as was supposed earlier. Near-infrared (NIR) spectroscopy, especially NIR emission line analysis, could be advantageous in shedding light on the true nucleus identity. Using Flamingos-2 at Gemini South we have taken deep K-band spectra along the major axis of the central structure and through the brightest infrared source. In this work, we present evidence showing that the brightest NIR and mid-infrared source in the central region, already known as radio source TH7 and so far considered just a large stellar supercluster, in fact presents various symptoms of a genuine galactic nucleus. Therefore, it should be considered a valid nucleus candidate. Mentioning some distinctive aspects, it is the most massive compact infrared object in the central region, located at 2.″0 of the symmetry center of the galactic bar, as measured in the K-band emission. Moreover, our data indicate that this object is surrounded by a large circumnuclear stellar disk and it is also located at the rotation center of the large molecular gas disk of NGC 253. Furthermore, a kinematic residual appears in the H2 rotation curve with a sinusoidal shape consistent with an outflow centered in the candidate nucleus position. The maximum outflow velocity is located about 14 pc from TH7, which is consistent with the radius of a shell detected around the nucleus candidate, observed at 18.3 μm (Qa) and 12.8 μm ([Ne ii]) with T-ReCS. Also, the Brγ emission line profile shows a pronounced blueshift and this emission line also has the highest equivalent width at this

  19. Reducing stigma and discrimination: Candidate interventions

    PubMed Central

    Thornicroft, Graham; Brohan, Elaine; Kassam, Aliya; Lewis-Holmes, Elanor

    2008-01-01

    This paper proposes that stigma in relation to people with mental illness can be understood as a combination of problems of knowledge (ignorance), attitudes (prejudice) and behaviour (discrimination). From a literature review, a series of candidate interventions are identified which may be effective in reducing stigmatisation and discrimination at the following levels: individuals with mental illness and their family members; the workplace; and local, national and international. The strongest evidence for effective interventions at present is for (i) direct social contact with people with mental illness at the individual level, and (ii) social marketing at the population level. PMID:18405393

  20. Recruiting as much about families as candidate

    SciTech Connect

    Madison, Alison L.

    2011-06-05

    Monthly economic diversity column for Tri-City Herald: For businesses large and small, one of the biggest challenges to staying afloat and achieving growth is attracting and retaining key talent. And in an area such as the Tri-Cities, where many of our skilled professionals are geographical transplants and the technology-based economic growth we seek often requires highly specific skill sets, effective recruiting is especially critical. But it isn’t just about matching candidates with open positions and signing on the dotted line. In fact, members of the Three Rivers Entrepreneur Network were reminded at a recent presentation that recruiting is very much about attracting the family unit.

  1. New nova candidate in M81

    NASA Astrophysics Data System (ADS)

    Henze, M.; Sala, G.; Jose, J.; Figueira, J.; Hernanz, M.

    2016-06-01

    We report the discovery of a new nova candidate in the M81 galaxy on 16x200s stacked R filter CCD images, obtained with the 80 cm Ritchey-Chretien F/9.6 Joan Oro telescope at Observatori Astronomic del Montsec, owned by the Catalan Government and operated by the Institut d'Estudis Espacials de Catalunya, Spain, using a Finger Lakes PL4240-1-BI CCD Camera (with a Class 1 Basic Broadband coated 2k x 2k chip with 13.5 microns sq. pixels).

  2. Optical Nova Candidate in M 31

    NASA Astrophysics Data System (ADS)

    Henze, M.; Pietsch, W.; Burwitz, V.; Updike, A.; Hartmann, D.; Milne, P.; Williams, G.

    2008-02-01

    We report the discovery of an optical nova candidate in M 31 on a 12x60 s stacked R filter CCD image obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 Feb 07.17 UT with a magnitude of 18.2 and is clearly visible on several of the individual 60 s images.

  3. Optical Nova Candidates in M 31

    NASA Astrophysics Data System (ADS)

    Henze, M.; Burwitz, V.; Pietsch, W.; Updike, A.; Milne, P.; Williams, G.; Hartmann, D. H.

    2008-06-01

    We report the discovery of an optical nova candidate in M 31 on two 11x60s stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 June 06.47 and 07.47 UT with respective magnitudes of 18.0 and 17.9.

  4. New optical nova candidate in M 31

    NASA Astrophysics Data System (ADS)

    Burwitz, V.; Pietsch, W.; Henze, M.; Rodriguez, J.; Haswell, C. A.; Holmes, S.; Kolb, U.; Lucas, R.

    2010-06-01

    We report the discovery of a possible nova in M 31 on a 5x120s stacked unfiltered CCD image obtained with the 0.35-m f/11 OU/OAM PIRATE Schmidt-Cassegrain telescope (+ SBIG STL-1001E CCD camera) at Costitx, Mallorca, Spain on 2010 June 26.084 UT with a corresponding R magnitude of 17.8. The position for the nova candidate is RA = 00h44m04.48s, Dec = +41d28'34.2" (J2000, accuracy of 0.3"), which is 902" east and 746" north of the core of M 31.

  5. 11 CFR 100.88 - Volunteer activity for candidates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... stickers, handbills, brochures, posters, and yard signs) is not a contribution to such candidate...

  6. 11 CFR 100.88 - Volunteer activity for candidates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... stickers, handbills, brochures, posters, and yard signs) is not a contribution to such candidate...

  7. 11 CFR 100.88 - Volunteer activity for candidates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... stickers, handbills, brochures, posters, and yard signs) is not a contribution to such candidate...

  8. 11 CFR 100.148 - Volunteer activity for candidate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... costs of that candidate's campaign materials that include information on or any reference to a...

  9. 11 CFR 100.88 - Volunteer activity for candidates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... the costs of that candidate's campaign materials that include information on or any reference to...

  10. 11 CFR 103.4 - Vice Presidential candidate campaign depositories.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... designated by the principal campaign committee of a political party's candidate for President shall be the campaign depository for that political party's candidate for the office of Vice President....

  11. 11 CFR 100.88 - Volunteer activity for candidates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... stickers, handbills, brochures, posters, and yard signs) is not a contribution to such candidate...

  12. Chaotic and stochastic processes in the accretion flows of the black hole X-ray binaries revealed by recurrence analysis

    NASA Astrophysics Data System (ADS)

    Suková, Petra; Grzedzielski, Mikolaj; Janiuk, Agnieszka

    2016-02-01

    variability in the microquasars GRS 1915+105 and IGR J17091-3624. Furthermore, we also find significant traces of nonlinear dynamics in three other sources: GX 339-4, XTE J1550-564 and GRO J1655-40, particularly in the disk-dominated soft state, as well as in the intermediate states at the rising and declining phase of the outburst. Only for the source XTE J1650-500 no observation with such variability pattern was found. This is possibly due to the global accretion rate in this source being too small for the limit-cycle instability to develop.

  13. Gamma-Ray Pulsar Candidates for GLAST

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.

    2008-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) will be launched this year, and its Large Area Telescope (LAT) is expected to discover scores to hundreds of gamma-ray pulsars. This poster discusses which of the over 1700 known pulsars, mostly visible only at radio frequencies, are likely to emit greater than 100 MeV gamma rays with intensities detectable by the LAT. The main figure of merit used to select gamma-ray pulsar candidates is sqrt(E-dot)/d2, where E-dot is the energy loss due to rotational spin-down, and d is the distance to the pulsar. The figure of merit incorporates spin-down flux at earth (proportional to E-dot/d2) times efficiency, assumed proportional to l/sqrt(E-dot). A few individual objects are cited to illustrate the issues. Since large E-dot pulsars also tend to have large timing noise and occasional glitches, their ephemerides can become inaccurate in weeks to months. To detect and study the gamma-ray emission the photons must be accurately tagged with the pulse phase. With hours to days between gamma-ray photon arrival times from a pulsar and months to years of LAT exposure needed for good detections, GLAST will rely on radio and X-ray timing measurements throughout the continuous gamma-ray observations. The poster will describe efforts to coordinate pulsar timing of the candidate gamma-ray pulsars.

  14. Gamma-Ray Pulsar Candidates for GLAST

    NASA Technical Reports Server (NTRS)

    Thompson, David J.; Smith, D. A.; Dumora, D.; Guillemot, L.; Parent, D.; Reposeur, T.; Grove, E.; Romani, R. W.; Thorsett, S. E.

    2007-01-01

    The Gamma-ray Large Area Space Telescope (GLAST) will be launched less than a year from now, and its Large Area Telescope (LAT) is expected to discover scores to hundreds of gamma-ray pulsars. This poster discusses which of the over 1700 known pulsars, mostly visible only at radio Erequencies, are likely to emit greater than l00 MeV gamma rays with intensities detectable by the LAT. The main figure of merit used to select gamma-ray pulsar candidates is sqrt(E-dot)/d^2, where E-dot is the energy loss due to rotational spindown, and d is the distance to the pulsar. The figure of merit incorporates spin-down flux at earth (proportional to E-dot/d^2) times efficiency, assumed proportional to 1/sqrt(E-dot). A few individual objects are cited to illustrate the issues. Since large E-dot pulsars also tend to have large timing noise and occasional glitches, their ephemerides can become inaccurate in weeks to months. To detect and study the gamma-ray emission the photons must be accurately tagged with the pulse phase. With hours to days between gamma-ray photon arrival times from a pulsar and months to years of LAT exposure needed for good detections, GLAST will need timing measurements throughout the continuous gamma-ray observations. The poster will describe efforts to coordinate pulsar timing of the candidate gamma-ray pulsars.

  15. CHIMERIC ALPHAVIRUS VACCINE CANDIDATES FOR CHIKUNGUNYA

    PubMed Central

    Wang, Eryu; Volkova, Eugenia; Adams, A. Paige; Forrester, Naomi; Xiao, Shu-Yuan; Frolov, Ilya; Weaver, Scott C.

    2008-01-01

    Chikungunya virus (CHIKV) is an emerging alphavirus that has caused major epidemics in India and islands off the east coast of Africa since 2005. Importations into Europe and the Americas, including one that led to epidemic transmission in Italy during 2007, underscore the risk of endemic establishment elsewhere. Because there is no licensed human vaccine, and an attenuated Investigational New Drug product developed by the U.S. Army causes mild arthritis in some vaccinees, we developed chimeric alphavirus vaccine candidates using either Venezuelan equine encephalitis attenuated vaccine strain TC-83, a naturally attenuated strain of eastern equine encephalitis virus (EEEV), or Sindbis virus as a backbone and the structural protein genes of CHIKV. All vaccine candidates replicated efficiently in cell cultures, and were highly attenuated in mice. All of the chimeras also produced robust neutralizing antibody responses, although the TC-83 and EEEV backbones appeared to offer greater immunogenicity. Vaccinated mice were fully protected against disease and viremia after CHIKV challenge. PMID:18692107

  16. Phenol sulfotransferases: Candidate genes for Batten disease

    SciTech Connect

    Dooley, T.P.; Probst, P.; Obermoeller, R.D.

    1995-06-05

    Batten disease (juvenile-onset neuronal ceroid lipofuscinosis; JNCL) is an autosomal recessive neurodegenerative disorder, characterized by the cytosomal accumulation of autofluorescent protolipopigments in neurons and other cell types. The Batten disease gene (CLN3) has not yet been identified, but has been mapped to a small region of human chromosome area 16p12.1-p11.2. We recently reported the fortuitous discovery that the cytosolic phenol sulfotransferase gene (STP) is located within this same interval of chromosome 16p. Since phenol sulfotransferase is expressed in neurons, can sulfate lipophilic phenolic compounds, and is mapped near CLN3, STP is considered as a candidate gene for Batten disease. YAC and cosmid cloning results have further substantiated the close proximity of STP and a highly related sulfotransferase (STM), encoding the catecholamine-preferring enzyme, to the CLN3 region of chromosome 16p. In this report, we summarize some of the recent progress in the identification of two phenol sulfotransferase genes (STP and STM) as positional candidate genes for Batten disease. 42 refs., 1 tab.

  17. Nonclinical Development of BCG Replacement Vaccine Candidates.

    PubMed

    Velmurugan, Kamalakannan; Grode, Leander; Chang, Rosemary; Fitzpatrick, Megan; Laddy, Dominick; Hokey, David; Derrick, Steven; Morris, Sheldon; McCown, David; Kidd, Reginald; Gengenbacher, Martin; Eisele, Bernd; Kaufmann, Stefan H E; Fulkerson, John; Brennan, Michael J

    2013-01-01

    The failure of current Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccines, given to neonates to protect against adult tuberculosis and the risk of using these live vaccines in HIV-infected infants, has emphasized the need for generating new, more efficacious and safer replacement vaccines. With the availability of genetic techniques for constructing recombinant BCG (rBCG) strains containing well-defined gene deletions or insertions, new vaccine candidates are under evaluation at both the preclinical and clinical stages of development. Since most BCG vaccines in use today were evaluated in clinical trials decades ago and are produced by outdated processes, the development of new BCG vaccines offers a number of advantages that include a modern well-defined manufacturing process along with state-of-the-art evaluation of safety and efficacy in target populations. We provide a description of the preclinical development of two novel rBCGs, VPM1002 that was constructed by adding a modified hly gene coding for the protein listeriolysin O (LLO) from Listeria monocytogenes and AERAS-422, which carries a modified pfoA gene coding for the protein perfringolysin O (PFO) from Clostridium perfringens, and three genes from Mycobacterium tuberculosis. Novel approaches like these should be helpful in generating stable and effective rBCG vaccine candidates that can be better characterized than traditional BCG vaccines. PMID:26343962

  18. Pulsar candidates towards Fermi unassociated sources

    NASA Astrophysics Data System (ADS)

    Frail, D. A.; Mooley, K. P.; Jagannathan, P.; Intema, H. T.

    2016-09-01

    We report on a search for steep spectrum radio sources within the 95 per cent confidence error ellipses of the Fermi unassociated sources from the Large Area Telescope (LAT). Using existing catalogues and the newly released Giant Metrewave Radio Telescope all-sky survey at 150 MHz, we identify compact radio sources that are bright at MHz frequencies but faint or absent at GHz frequencies. Such steep spectrum radio sources are rare and constitute a sample of pulsar candidates, selected independently of period, dispersion measure, interstellar scattering and orbital parameters. We find point-like, steep spectrum candidates towards 11 Fermi sources. Based on the gamma-ray/radio positional coincidence, the rarity of such radio sources, and the properties of the 3FGL sources themselves, we argue that many of these sources could be pulsars. They may have been missed by previous radio periodicity searches due to interstellar propagation effects or because they lie in an unusually tight binary. If this hypothesis is correct, then renewed gamma-ray and radio periodicity searches at the positions of the steep spectrum radio sources may reveal pulsations.

  19. Surgical evaluation of candidates for cochlear implants

    NASA Technical Reports Server (NTRS)

    Black, F. O.; Lilly, D. J.; Fowler, L. P.; Stypulkowski, P. H.

    1987-01-01

    The customary presentation of surgical procedures to patients in the United States consists of discussions on alternative treatment methods, risks of the procedure(s) under consideration, and potential benefits for the patient. Because the contents of the normal speech signal have not been defined in a way that permits a surgeon systematically to provide alternative auditory signals to a deaf patient, the burden is placed on the surgeon to make an arbitrary selection of candidates and available devices for cochlear prosthetic implantation. In an attempt to obtain some information regarding the ability of a deaf patient to use electrical signals to detect and understand speech, the Good Samaritan Hospital and Neurological Sciences Institute cochlear implant team has routinely performed tympanotomies using local anesthesia and has positioned temporary electrodes onto the round windows of implant candidates. The purpose of this paper is to review our experience with this procedure and to provide some observations that may be useful in a comprehensive preoperative evaluation for totally deaf patients who are being considered for cochlear implantation.

  20. Elemental abundances of solar sibling candidates

    SciTech Connect

    Ramírez, I.; Lambert, D. L.; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Bajkova, A. T.; Bobylev, V. V.; Wittenmyer, R. A.

    2014-06-01

    Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high-resolution, high signal-to-noise ratio spectra for 30 of these objects to determine, using detailed elemental abundance analysis, if they could be true solar siblings. Only two of the candidates are found to have solar chemical composition. Updated modeling of the stars' past orbits in a realistic Galactic potential reveals that one of them, HD 162826, satisfies both chemical and dynamical conditions for being a sibling of the Sun. Measurements of rare-element abundances for this star further confirm its solar composition, with the only possible exception of Sm. Analysis of long-term high-precision radial velocity data rules out the presence of hot Jupiters and confirms that this star is not in a binary system. We find that chemical tagging does not necessarily benefit from studying as many elements as possible but instead from identifying and carefully measuring the abundances of those elements that show large star-to-star scatter at a given metallicity. Future searches employing data products from ongoing massive astrometric and spectroscopic surveys can be optimized by acknowledging this fact.

  1. MICROLENSING BINARIES WITH CANDIDATE BROWN DWARF COMPANIONS

    SciTech Connect

    Shin, I.-G.; Han, C.; Gould, A.; Skowron, J.; Udalski, A.; Szymanski, M. K.; Kubiak, M.; Soszynski, I.; Pietrzynski, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozlowski, S.; Wyrzykowski, L.; Sumi, T.; Dominik, M.; Beaulieu, J.-P.; Tsapras, Y.; Bozza, V.; Abe, F.; Collaboration: OGLE Collaboration; MOA Collaboration; muFUN Collaboration; and others

    2012-12-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during the 2004-2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found seven candidate events: OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured masses of the brown dwarf companions are 0.02 {+-} 0.01 M {sub Sun} and 0.019 {+-} 0.002 M {sub Sun} for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well-covered light curves increases with new-generation searches.

  2. Nonclinical Development of BCG Replacement Vaccine Candidates

    PubMed Central

    Velmurugan, Kamalakannan; Grode, Leander; Chang, Rosemary; Fitzpatrick, Megan; Laddy, Dominick; Hokey, David; Derrick, Steven; Morris, Sheldon; McCown, David; Kidd, Reginald; Gengenbacher, Martin; Eisele, Bernd; Kaufmann, Stefan H.E.; Fulkerson, John; Brennan, Michael J.

    2013-01-01

    The failure of current Mycobacterium bovis bacille Calmette–Guérin (BCG) vaccines, given to neonates to protect against adult tuberculosis and the risk of using these live vaccines in HIV-infected infants, has emphasized the need for generating new, more efficacious and safer replacement vaccines. With the availability of genetic techniques for constructing recombinant BCG (rBCG) strains containing well-defined gene deletions or insertions, new vaccine candidates are under evaluation at both the preclinical and clinical stages of development. Since most BCG vaccines in use today were evaluated in clinical trials decades ago and are produced by outdated processes, the development of new BCG vaccines offers a number of advantages that include a modern well-defined manufacturing process along with state-of-the-art evaluation of safety and efficacy in target populations. We provide a description of the preclinical development of two novel rBCGs, VPM1002 that was constructed by adding a modified hly gene coding for the protein listeriolysin O (LLO) from Listeria monocytogenes and AERAS-422, which carries a modified pfoA gene coding for the protein perfringolysin O (PFO) from Clostridium perfringens, and three genes from Mycobacterium tuberculosis. Novel approaches like these should be helpful in generating stable and effective rBCG vaccine candidates that can be better characterized than traditional BCG vaccines. PMID:26343962

  3. Some Candidates for Solar Gravity Modes

    NASA Astrophysics Data System (ADS)

    Thomson, David J.

    2015-04-01

    Since the accidental discovery of solar modes in space (Thomson,Maclennan, and Lanzerotti, Nature, 1995) work has continued and there are now a few candidates for identified solar gravity modes using charged particles and interplanetary magnetic field data. Contrary to initial expectations, there is a preference for higher-l modes, typically l = 2 to 5.Second, different frequencies are expected at ACE (at L1) and Ulysses, in an almost sidereal solar-polar orbit. Given a candidate detection at ACE where signal-to-noise ratios are higher, one can then shift frequencies by ±32m nHz and test for agreement at Ulysses.Third, the 7.5 degree inclination of the ecliptic on the solar equator splits odd-parity modes at ACE by32 nHz. The two sub-singlets have a defined phase relation that can be used as a further check on parity. Two such modes are G2,-1 at 296.195 uHz and G3,-2 at 296.887 uHz. Both have all 2l+1 singlets detected on both ACE and Ulysses.The 11 singlets of the G5,-1 mode are also all detected above the 99% level. The mode has a center frequency of 383.812 uHz with a1 ≈ 918 nHz.

  4. Advanced vaccine candidates for Lassa fever.

    PubMed

    Lukashevich, Igor S

    2012-11-01

    Lassa virus (LASV) is the most prominent human pathogen of the Arenaviridae. The virus is transmitted to humans by a rodent reservoir, Mastomys natalensis, and is capable of causing lethal Lassa Fever (LF). LASV has the highest human impact of any of the viral hemorrhagic fevers (with the exception of Dengue Fever) with an estimated several hundred thousand infections annually, resulting in thousands of deaths in Western Africa. The sizeable disease burden, numerous imported cases of LF in non-endemic countries, and the possibility that LASV can be used as an agent of biological warfare make a strong case for vaccine development. Presently there is no licensed vaccine against LF or approved treatment. Recently, several promising vaccine candidates have been developed which can potentially target different groups at risk. The purpose of this manuscript is to review the LASV pathogenesis and immune mechanisms involved in protection. The current status of pre-clinical development of the advanced vaccine candidates that have been tested in non-human primates will be discussed. Major scientific, manufacturing, and regulatory challenges will also be considered. PMID:23202493

  5. Advanced Vaccine Candidates for Lassa Fever

    PubMed Central

    Lukashevich, Igor S.

    2012-01-01

    Lassa virus (LASV) is the most prominent human pathogen of the Arenaviridae. The virus is transmitted to humans by a rodent reservoir, Mastomys natalensis, and is capable of causing lethal Lassa Fever (LF). LASV has the highest human impact of any of the viral hemorrhagic fevers (with the exception of Dengue Fever) with an estimated several hundred thousand infections annually, resulting in thousands of deaths in Western Africa. The sizeable disease burden, numerous imported cases of LF in non-endemic countries, and the possibility that LASV can be used as an agent of biological warfare make a strong case for vaccine development. Presently there is no licensed vaccine against LF or approved treatment. Recently, several promising vaccine candidates have been developed which can potentially target different groups at risk. The purpose of this manuscript is to review the LASV pathogenesis and immune mechanisms involved in protection. The current status of pre-clinical development of the advanced vaccine candidates that have been tested in non-human primates will be discussed. Major scientific, manufacturing, and regulatory challenges will also be considered. PMID:23202493

  6. Perceptions of Candidate Teachers about Concept of the Project

    ERIC Educational Resources Information Center

    Tortop, Hasan Said

    2014-01-01

    The aim of study is to investigate candidate teachers' metaphors about project concept in Turkey. Study group of research is 171 candidate teachers enrolled 2011-2012 educational terms one of the faculty of education in Turkey. Data was obtained from the candidate teachers' completion of the sentence "Project is like ..., because ...".…

  7. 11 CFR 9033.1 - Candidate and committee agreements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... authorized committee(s) will comply with the conditions set forth in 11 CFR 9033.1(b). The candidate may... qualified campaign expenses as defined at 11 CFR 9032.9. (2) The candidate and the candidate's authorized committee(s) will comply with the documentation requirements set forth in 11 CFR 9033.11. (3) The...

  8. Changing Perceptions of Teacher Candidates in High-Needs Schools

    ERIC Educational Resources Information Center

    DeJarnette, Nancy K.

    2016-01-01

    Candidates enter teacher education programs with established beliefs about diversity and urban education. These belief systems impact decisions that teacher candidates make both now and in the future. Providing opportunities for candidates to spend quality time in an urban Professional Development School (PDS) setting with the support and guidance…

  9. 15 CFR 922.21 - Selection of active candidates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Selection of active candidates. 922.21... Selection of active candidates. (a) The Secretary shall, from time to time, select a limited number of sites... standards set forth in section 303 of the Act. (b) Selection of a site as an Active Candidate shall...

  10. Opinions of the Geography Teacher Candidates toward Mind Maps

    ERIC Educational Resources Information Center

    Seyihoglu, Aysegul

    2013-01-01

    The purpose of this study is to reveal the opinions of the teacher candidates about mind mapping technique used in Geography education of undergraduate program. In this study, the qualitative research techniques were used. The study group consists of 55 teacher candidates. The teacher candidates have been asked for their opinions about the process…

  11. Identity Functions and Empathetic Tendencies of Teacher Candidates

    ERIC Educational Resources Information Center

    Ay, Alpaslan; Kadi, Aysegul

    2016-01-01

    Objective of this research is to investigate identity functions and empathetic tendencies of teacher candidates. Sample consists of 232 teacher candidates in social studies teacher education. Survey model is preferred to investigate the difference between identity functions and empathetic tendencies of teacher candidates. And also correlational…

  12. Parliamentary Privilege--The Candidates. Research Brief. Edition 3

    ERIC Educational Resources Information Center

    Sutton Trust, 2015

    2015-01-01

    The research brief, "Parliamentary Privilege", looks at the educational backgrounds of candidates in winnable seats. The study included candidates selected by mid-December 2014 who were replacing serving MPs for the same party or in target seats with a reasonable possibility of winning. More than half of the candidates attended Russell…

  13. Mirror Images: Teacher Candidates' Perceptions of Disposition Development

    ERIC Educational Resources Information Center

    Bercaw, Lynne A.; Summers, Deborah G.; Colby, Susan A.; Payne, Maggie

    2012-01-01

    The complexity of disposition development for teacher candidates continues to be discussed and debated in teacher education. This study compares two programs and the different ways each approaches the disposition development of their respective candidates. More than 200 candidates from two institutions were surveyed on how and where they perceived…

  14. The Marketing Market: Matching Academic Hiring Institutions and Job Candidates

    ERIC Educational Resources Information Center

    Basil, Michael D.; Basil, Debra Z.

    2008-01-01

    Hiring faculty is a challenge in the field of marketing. One important factor is a shortage of candidates. The problem is exacerbated, however, by an imperfect match between jobs and candidates. This study examines the homogeneity of academic jobs and candidates. Surveys were conducted with both parties. The results show that institutions and…

  15. 14 CFR 1214.1106 - Selection of astronaut candidates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Selection of astronaut candidates. 1214.1106 Section 1214.1106 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT NASA Astronaut Candidate Recruitment and Selection Program § 1214.1106 Selection of astronaut candidates....

  16. Image of Ideal Teachers among Turkish Young Teacher Candidates

    ERIC Educational Resources Information Center

    Budak, Yusuf

    2011-01-01

    The aim of the current study is to determine the perception of teacher candidates concerning ideal teachers and to determine the perception of qualitative teachers that teacher candidates have and put a light on the selection of teacher candidates and the development of teacher-training programs. In the study, quantitative and qualitative…

  17. Concerns of Teacher Candidates in an Early Field Experience

    ERIC Educational Resources Information Center

    Chang, Sau Hou

    2009-01-01

    The present study examined the concerns of teacher candidates in an early field experience. Thirty-five teacher candidates completed the Teacher Concerns Checklist (TCC, Fuller & Borich, 2000) at the beginning, middle and end of their early field experiences. Results showed that teacher candidates ranked impact as the highest concern, self as the…

  18. Cognitive Styles in Admission Procedures for Assessing Candidates of Architecture

    ERIC Educational Resources Information Center

    Casakin, Hernan; Gigi, Ariela

    2016-01-01

    Cognitive style has a strong predictive power in academic and professional success. This study investigated the cognitive profile of candidates studying architecture. Specifically, it explored the relation between visual and verbal cognitive styles, and the performance of candidates in admission procedures. The cognitive styles of candidates who…

  19. Views on Values Education: From Teacher Candidates to Experienced Teachers

    ERIC Educational Resources Information Center

    Iscan, Canay Demirhan

    2015-01-01

    This study aimed to identify the views of experienced class teachers and class teacher candidates on values education. It conducted standard open-ended interviews with experienced class teachers and teacher candidates. The study group comprised 9 experienced class teachers from different socio-economic levels and 9 teacher candidates with…

  20. Using a New Crustal Thickness Model to Test Previous Candidate Lunar Basins and to Search for New Candidates

    NASA Technical Reports Server (NTRS)

    Meyer, H. M.; Frey, H. V.

    2012-01-01

    A new crustal thickness model was used to test the viability of 110 candidate large lunar basins previously identified using older topographic and crustal thickness data as well as photogeologic data. The new model was also used to search for new candidate lunar basins greater than 300 km in diameter. We eliminated 11 of 27 candidates previously identified in the older crustal thickness model, and found strong evidence for at least 8 new candidates.

  1. Comparative Candidate Evaluation as a Function of Election Level and Candidate Incumbency.

    ERIC Educational Resources Information Center

    Hellweg, Susan A.; And Others

    A study examined the evaluative structures employed by voters in making decisions about political contenders, specifically as a function of the level of the election involved and the incumbent-challenger status of the candidates. Data were obtained by questionnaires administered within two weeks prior to the 1984 general election to 550…

  2. A direct molecular link between the autism candidate gene RORa and the schizophrenia candidate MIR137

    NASA Astrophysics Data System (ADS)

    Devanna, Paolo; Vernes, Sonja C.

    2014-02-01

    Retinoic acid-related orphan receptor alpha gene (RORa) and the microRNA MIR137 have both recently been identified as novel candidate genes for neuropsychiatric disorders. RORa encodes a ligand-dependent orphan nuclear receptor that acts as a transcriptional regulator and miR-137 is a brain enriched small non-coding RNA that interacts with gene transcripts to control protein levels. Given the mounting evidence for RORa in autism spectrum disorders (ASD) and MIR137 in schizophrenia and ASD, we investigated if there was a functional biological relationship between these two genes. Herein, we demonstrate that miR-137 targets the 3'UTR of RORa in a site specific manner. We also provide further support for MIR137 as an autism candidate by showing that a large number of previously implicated autism genes are also putatively targeted by miR-137. This work supports the role of MIR137 as an ASD candidate and demonstrates a direct biological link between these previously unrelated autism candidate genes.

  3. The Kepler Q1-Q12 Planet Candidate Catalogue

    NASA Astrophysics Data System (ADS)

    Rowe, Jason; Kepler Team

    2014-01-01

    An update on the Kepler Planetary Candidate Catalogue (http://exoplanetarchive.ipac.caltech.edu/docs/Kepler_KOI_docs.html) will be presented that incorporates results of three years of nearly continuous, high precision photometry. Through a series of tests to exclude false-positives, primarily caused by eclipsing binary stars, over 900 additional planetary candidates have been discovered. Approximately 50 of the new candidates have equilibrium temperatures less than 300 K. More than 400 of the new planetary candidates have a radius less that 1.5 Rearth. A handful of the new candidates meet both criteria, roughly doubling the number of near Earth analogs.

  4. Chandra Pilot Survey of Extrasolar Planet Candidates

    NASA Astrophysics Data System (ADS)

    Tsuboi, Yohko

    2012-09-01

    We propose to detect planetary-mass companion around young nearby stars by X-ray direct imaging observations with Chandra. Our goals are to determine I. if the X-ray band can be a new probe to the exo-planet search, and II. if a planet emit detectable X-rays with a magnetic origin at a young age. This should be a challenging observation but a brand-new discovery space unique to Chandra. The abundant population of YSOs in the same field of view will enable us to obtain complete X-ray catalogues of YSOs with all categories of masses. We will also execute simultaneous deep NIR observations with IRSF/SIRIUS and Nishiharima 2m telescope to search for the other X-ray-emitting very low-mass objects near our aiming planet candidates.

  5. Triton stellar occultation candidates: 1995-1999

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. L.

    1995-01-01

    We have completed a search for candidates for stellar occultations by Triton over the years 1995-1999. CCd strip scan images provided star positions in the relevant sky area to a depth of about 17.5 R magnitude. Over this time period, we find that Triton passes within 1.0 arcsec of 75 stars. Appulses with geocentric minimum separations of less than 0.35 arcsec will result in stellar occultations, but further astrometry and photometry is necessary to refine individual predictions for identification of actual occultations. Finder charts are included to aid in further studies and prediction refinement. The two most promising potential occultations, Tr176 and Tr180, occur in 1997.

  6. Pituitary stem cells: candidates and implications.

    PubMed

    Nassiri, Farshad; Cusimano, Michael; Zuccato, Jeff A; Mohammed, Safraz; Rotondo, Fabio; Horvath, Eva; Syro, Luis V; Kovacs, Kalman; Lloyd, Ricardo V

    2013-09-01

    The pituitary is the master endocrine gland of the body. It undergoes many changes after birth, and these changes may be mediated by the differentiation of pituitary stem cells. Stem cells in any tissue source must display (1) pluripotent capacity, (2) capacity for indefinite self-renewal, and (3) a lack of specialization. Unlike neural stem cells identified in the hippocampus and subventricular zone, pituitary stem cells are not associated with one specific cell type. There are many major candidates that are thought to be potential pituitary stem cell sources. This article reviews the evidence for each of the major cell types and discuss the implications of identifying a definitive pituitary stem cell type. PMID:23423660

  7. Computational assessment of organic photovoltaic candidate compounds

    NASA Astrophysics Data System (ADS)

    Borunda, Mario; Dai, Shuo; Olivares-Amaya, Roberto; Amador-Bedolla, Carlos; Aspuru-Guzik, Alan

    2015-03-01

    Organic photovoltaic (OPV) cells are emerging as a possible renewable alternative to petroleum based resources and are needed to meet our growing demand for energy. Although not as efficient as silicon based cells, OPV cells have as an advantage that their manufacturing cost is potentially lower. The Harvard Clean Energy Project, using a cheminformatic approach of pattern recognition and machine learning strategies, has ranked a molecular library of more than 2.6 million candidate compounds based on their performance as possible OPV materials. Here, we present a ranking of the top 1000 molecules for use as photovoltaic materials based on their optical absorption properties obtained via time-dependent density functional theory. This computational search has revealed the molecular motifs shared by the set of most promising molecules.

  8. Surface erosion effects of candidate fusion materials

    SciTech Connect

    Navinsek, B.

    1984-09-01

    Some candidate fusion materials such as nickelbase alloys and graphites were studied, because of their importance as first wall components in CTR devices. Polycrystalline samples of Inconel 600, Inconel 625, Nimonic alloy PE 16, nuclear grade graphite ATJ and pyrolytic graphite were investigated. Results for surface damage and topography, blistering, flaking, ion erosion and sputtering yields are reported for irradiations with low energy He/sup +/ ions (5-12 keV) at room temperature, using total ion doses up to 2 x 10/sup 19/ ions cm/sup -2/. SEM, TEM and AES analyses were used to identify surface damage, structure and compositional changes after irradiation. Comparative studies of the ion erosion yield of nickel-base alloys, as measured by the step-height technique, were made. Total sputtering yields were determined dynamically for sputtered films of these alloys using a quartz crystal microbalance. The yields were studied as a function of ion dose, energy and surface roughness.

  9. Bisphosphonate drug holiday: choosing appropriate candidates.

    PubMed

    Ro, Cynthia; Cooper, Odelia

    2013-03-01

    Osteoporosis related fractures contribute to morbidity and mortality in U.S. patients, placing a heavy financial burden on society. Randomized clinical trials involving over 30,000 subjects have established bisphosphonates' efficacy in reducing the incidence of fragility fractures. However, as bisphosphonates are retained for years in the skeleton, reports of adverse events from prolonged use are surfacing in the literature, namely, esophageal cancer, atrial fibrillation, osteonecrosis of the jaw, and atypical fracture development. The concept of a drug holiday has been proposed to potentially reduce incidence of these adverse events. This review will highlight the benefits and risks of bisphosphonate therapy and discuss the extension data available from the bisphosphonate trials. As randomized clinical trial evidence is not yet available on who may qualify for drug holiday, this review will provide suggestions for clinicians on identification of possible candidates and monitoring during a bisphosphonate drug holiday. PMID:23296595

  10. Nonzero Quadrupole Moments of Candidate Tetrahedral Bands

    SciTech Connect

    Bark, R. A.; Lawrie, E. A.; Lawrie, J. J.; Mullins, S. M.; Murray, S. H. T.; Ncapayi, N. J.; Smit, F. D.; Sharpey-Schafer, J. F.; Lindsay, R.

    2010-01-15

    Negative-parity bands in the vicinity of {sup 156}Gd and {sup 160}Yb have been suggested as candidates for the rotation of tetrahedral nuclei. We report the observation of the odd and even-spin members of the lowest energy negative-parity bands in {sup 160}Yb and {sup 154}Gd. The properties of these bands are similar to the proposed tetrahedral band of {sup 156}Gd and its even-spin partner. Band-mixing calculations are performed and absolute and relative quadrupole moments deduced for {sup 160}Yb and {sup 154}Gd. The values are inconsistent with zero, as required for tetrahedral shape, and the bands are interpreted as octupole vibrational bands. The failure to observe the in-band E2 transitions of the bands at low spins can be understood using the measured B(E1) and B(E2) values.

  11. New potential AChE inhibitor candidates.

    PubMed

    de Paula, A A N; Martins, J B L; dos Santos, M L; Nascente, L de C; Romeiro, L A S; Areas, T F M A; Vieira, K S T; Gambôa, N F; Castro, N G; Gargano, R

    2009-09-01

    We have theoretically studied new potential candidates of acetylcholinesterase (AChE) inhibitors designed from cardanol, a non-isoprenoid phenolic lipid of cashew Anacardium occidentale nut-shell liquid. The electronic structure calculations of fifteen molecule derivatives from cardanol were performed using B3LYP level with 6-31G, 6-31G(d), and 6-311+G(2d,p) basis functions. For this study we used the following groups: methyl, acetyl, N,N-dimethylcarbamoyl, N,N-dimethylamine, N,N-diethylamine, piperidine, pyrrolidine, and N,N-methylbenzylamine. Among the proposed compounds we identified that the structures with substitution by N,N-dimethycarbamoyl, N,N-dimethylamine, and pyrrolidine groups were better correlated to rivastigmine, and represent possible AChE inhibitors against Alzheimer disease. PMID:19446931

  12. Ocriplasmin: who is the best candidate?

    PubMed Central

    Prospero Ponce, Claudia M; Stevenson, William; Gelman, Rachel; Agarwal, Daniel R; Christoforidis, John B

    2016-01-01

    Enzymatic vitreolysis is currently the focus of attention around the world for treating vitreomacular traction and full-thickness macular hole. Induction of posterior vitreous detachment is an active area of developmental clinical and basic research. Despite exerting an incompletely elucidated physiological effect, ocriplasmin (also known as microplasmin) has been recognized to serve as a well-tolerated intravitreal injection for the treatment of vitreomacular traction and full-thickness macular hole. There are several unexplored areas of intervention where enzymatic vitreolysis could potentially be used (ie, diabetic macular edema). Recent promising studies have included combinations of enzymatic approaches and new synthetic molecules that induce complete posterior vitreous detachment as well as antiangiogenesis. Although no guidelines have been proposed for the use of ocriplasmin, this review attempts to aid physicians in answering the most important question, “Who is the best candidate?” PMID:27051270

  13. Assessment of Live Plague Vaccine Candidates.

    PubMed

    Feodorova, Valentina A; Sayapina, Lidiya V; Motin, Vladimir L

    2016-01-01

    Since its creation in the early twentieth century, live plague vaccine EV has been successfully applied to millions of people without severe complications. This vaccine has been proven to elicit protection against both bubonic and pneumonic plague, and it is still in use in populations at risk mainly in the countries of the former Soviet Union. Despite extensive efforts in developing subunit vaccines, there is a reviving interest in creation of a precisely attenuated strain of Yersinia pestis superior to the EV that can serve as a live plague vaccine with improved characteristics. Here we summarize decades of experience of the Russian anti-plague research in developing a standard protocol for early-stage evaluation of safety and immunogenicity of live plague vaccines. This protocol allows step-by-step comparison of the novel test candidates with the EV vaccine by using subcutaneous immunization and bubonic plague infection models in two animal species, e.g., guinea pigs and mice. PMID:27076149

  14. Mining biological databases for candidate disease genes

    NASA Astrophysics Data System (ADS)

    Braun, Terry A.; Scheetz, Todd; Webster, Gregg L.; Casavant, Thomas L.

    2001-07-01

    The publicly-funded effort to sequence the complete nucleotide sequence of the human genome, the Human Genome Project (HGP), has currently produced more than 93% of the 3 billion nucleotides of the human genome into a preliminary `draft' format. In addition, several valuable sources of information have been developed as direct and indirect results of the HGP. These include the sequencing of model organisms (rat, mouse, fly, and others), gene discovery projects (ESTs and full-length), and new technologies such as expression analysis and resources (micro-arrays or gene chips). These resources are invaluable for the researchers identifying the functional genes of the genome that transcribe and translate into the transcriptome and proteome, both of which potentially contain orders of magnitude more complexity than the genome itself. Preliminary analyses of this data identified approximately 30,000 - 40,000 human `genes.' However, the bulk of the effort still remains -- to identify the functional and structural elements contained within the transcriptome and proteome, and to associate function in the transcriptome and proteome to genes. A fortuitous consequence of the HGP is the existence of hundreds of databases containing biological information that may contain relevant data pertaining to the identification of disease-causing genes. The task of mining these databases for information on candidate genes is a commercial application of enormous potential. We are developing a system to acquire and mine data from specific databases to aid our efforts to identify disease genes. A high speed cluster of Linux of workstations is used to analyze sequence and perform distributed sequence alignments as part of our data mining and processing. This system has been used to mine GeneMap99 sequences within specific genomic intervals to identify potential candidate disease genes associated with Bardet-Biedle Syndrome (BBS).

  15. CRISPLD2: a novel NSCLP candidate gene.

    PubMed

    Chiquet, Brett T; Lidral, Andrew C; Stal, Samuel; Mulliken, John B; Moreno, Lina M; Arcos-Burgos, Mauricio; Arco-Burgos, Mauricio; Valencia-Ramirez, Consuelo; Blanton, Susan H; Hecht, Jacqueline T

    2007-09-15

    Non-syndromic cleft lip with or without cleft palate (NSCLP) results from the complex interaction between genes and environmental factors. Candidate gene analysis and genome scans have been employed to identify the genes contributing to NSCLP. In this study, we evaluated the 16q24.1 chromosomal region, which has been identified by multiple genome scans as an NSCLP region of interest. Two candidate genes were found in the region: interferon regulatory factor 8 (IRF8) and cysteine-rich secretory protein LCCL domain containing 2 (CRISPLD2). Initially, Caucasian and Hispanic NSCLP multiplex families and simplex parent-child trios were genotyped for single nucleotide polymorphisms (SNPs) in both IRF8 and CRISPLD2. CRISPLD2 was subsequently genotyped in a data set comprised of NSCLP families from Colombia, South America. Linkage disequilibrium analysis identified a significant association between CRISPLD2 and NSCLP in both our Caucasian and Hispanic NSCLP cohorts. SNP rs1546124 and haplotypes between rs1546124 and either rs4783099 or rs16974880 were significant in the Caucasian multiplex population (P=0.01, P=0.002 and P=0.001, respectively). An altered transmission of CRISPLD2 SNPs rs8061351 (P=0.02) and rs2326398 (P=0.06) was detected in the Hispanic population. No association was found between CRISPLD2 and our Colombian population or IRF8 and NSCLP. In situ hybridization showed that CRISPLD2 is expressed in the mandible, palate and nasopharynx regions during craniofacial development at E13.5-E17.5, respectively. Altogether, these data suggest that genetic variation in CRISPLD2 has a role in the etiology of NSCLP. PMID:17616516

  16. CRISPLD2: a novel NSCLP candidate gene

    PubMed Central

    Chiquet, Brett T.; Lidral, Andrew C.; Stal, Samuel; Mulliken, John B.; Moreno, Lina M.; Arco-Burgos, Mauricio; Valencia-Ramirez, Consuelo; Blanton, Susan H.; Hecht, Jacqueline T.

    2013-01-01

    Non-syndromic cleft lip with or without cleft palate (NSCLP) results from the complex interaction between genes and environmental factors. Candidate gene analysis and genome scans have been employed to identify the genes contributing to NSCLP. In this study, we evaluated the 16q24.1 chromosomal region, which has been identified by multiple genome scans as an NSCLP region of interest. Two candidate genes were found in the region: interferon regulatory factor 8 (IRF8) and cysteine-rich secretory protein LCCL domain containing 2 (CRISPLD2). Initially, Caucasian and Hispanic NSCLP multiplex families and simplex parent–child trios were genotyped for single nucleotide polymorphisms (SNPs) in both IRF8 and CRISPLD2. CRISPLD2 was subsequently genotyped in a data set comprised of NSCLP families from Colombia, South America. Linkage disequilibrium analysis identified a significant association between CRISPLD2 and NSCLP in both our Caucasian and Hispanic NSCLP cohorts. SNP rs1546124 and haplotypes between rs1546124 and either rs4783099 or rs16974880 were significant in the Caucasian multiplex population (P = 0.01, P = 0.002 and P = 0.001, respectively). An altered transmission of CRISPLD2 SNPs rs8061351 (P = 0.02) and rs2326398 (P = 0.06) was detected in the Hispanic population. No association was found between CRISPLD2 and our Colombian population or IRF8 and NSCLP. In situ hybridization showed that CRISPLD2 is expressed in the mandible, palate and nasopharynx regions during craniofacial development at E13.5–E17.5, respectively. Altogether, these data suggest that genetic variation in CRISPLD2 has a role in the etiology of NSCLP. PMID:17616516

  17. Quasars Candidates in the Hubble Deep Field

    NASA Astrophysics Data System (ADS)

    Conti, A.; Kennefick, J. D.; Martini, P. L.; Omser, P. S.

    1996-12-01

    The Hubble Deep Field gives us an unprecedented view of our universe and an opportunity to study a wide range of questions in galaxy evolution and cosmology. Here, we will focus on the search for faint quasars and AGN in the crude combined images using a multicolor imaging analysis that has proven very successful in recent years. To produce a catalog of objects in the field, we used the FOCAS package for object detection with particular care to the set of input parameters used to minimize spurious detections. For each detected source we measured aperture magnitudes in several different apertures using the IRAF PHOT routine. For object classification we have chosen not to use the built in FOCAS routines, instead we have developed classification schemes that closely resemble those of Flynn at al. (1996) to distinguish resolved from unresolved objects in the Hubble Deep Field. We generated synthetic quasar spectra in the range 2.0candidate list is being formed. Routines were developed to determine the completeness of our data to point sources in the observed bands. The data are 50 % complete at 27.0(m) , 28.9(m) ,29.1(m) , 28.2(m) in the F300W (U), F450W (B), F606W (V) and F814W (I) filter respectively. These completeness limits closely approximate the 3sigma detection limit. We will present a list of quasars candidates and compare the results to expectations from previous surveys and extrapolations from current models. Our initial extrapolations, based on the luminosity function of Boyle (1991) and Warren at al. (1994), suggest the Hubble Deep Field may contain of order 10 quasars.

  18. Walking Capacity of Bariatric Surgery Candidates

    PubMed Central

    King, WC; Engel, SG; Elder, KA; Chapman, WH; Eid, GM; Wolfe, BM; Belle, SH

    2011-01-01

    Background This study characterizes the walking limitations of bariatric surgery candidates by age and body mass index (BMI) and determines factors independently associated with walking capacity. Setting Multi-institutional at research university hospitals in the United States. Methods 2458 participants of the Longitudinal Assessment of Bariatric Surgery study (age: 18-78 y, BMI: 33-94 kg/m2) attended a pre-operative research visit. Walking capacity was measured via self-report and the 400 meter Long Distance Corridor Walk (LDCW). Results Almost two-thirds (64%) of subjects reported limitations walking several blocks, 48% had an objectively-defined mobility deficit, and 16% reported at least some walking aid use. In multivariable analysis, BMI, older age, lower income and greater bodily pain were independently associated (p<.05) with walking aid use, physical discomfort during the LDCW, inability to complete the LDCW, and slower time to complete the LDCW. Female sex, Hispanic ethnicity (but not race), higher resting heart rate, history of smoking, several comoribidities (history of stroke, ischemic heart disease, diabetes, asthma, sleep apnea, venous edema with ulcerations), and depressive symptoms were also independently related (p<.05) to at least one measure of reduced walking capacity. Conclusions Walking limitations are common in bariatric surgery candidates, even among the least severely obese and youngest patients. Physical activity counseling must be tailored to individuals' abilities. While several factors identified in this study (e.g., BMI, age, pain, comorbidities) should be considered, directly assessing walking capacity will facilitate appropriate goal-setting. PMID:21937285

  19. Body dysmorphic disorder in aesthetic rhinoplasty candidates

    PubMed Central

    MR, Fathololoomi; Tabrizi A, Goljanian; Bafghi A, Fattahi; SA, Noohi; A, Makhdoom

    2013-01-01

    Objective: Body Dysmorphic Disorder (BDD) is a psychiatric disorder defined as obsessive ideas about distorted physical appearance, leading to social, professional and personal dysfunction. Many of these patients seek aesthetic surgery and are generally dissatisfied with the outcome of their surgery. In the present study patients coming to the otolaryngology clinic of Thaleghani Hospital in Tehran seeking rhinoplasty were evaluated. Methodology: Between October 2010 and October 2011, 130 patients seeking rhinoplasty were recruited in a cross-sectional study. These patients were consecutively interviewed in the otolaryngology clinic of Taleghani Hospital, Tehran, Iran. Questionnaires were filled containing demographic data. BDD was evaluated by a separate questionnaire. Hospital Anxiety and Depression Scale (HADS) questionnaire was filled to evaluate depression and anxiety. Data were analyzed by using SPSS software. The frequency and standard deviations were calculated. Differences between groups were evaluated by using the chi-square, and t-tests. Results: Ninety nine (76.2%) of rhinoplasty candidates were female and thirty one (23.8%) were male. Eighty five (65.4%) were single and thirty eight (29.2%) were married while seven were divorced. About 63.8% were University students or University graduates. Mean age was 26.43±6.29 years old. 41 patients (31.5%) had BDD. Among BDD patients 12 (29.3%) had concurrent depression and 11 (26.8%) had concurrent anxiety. No statistically significant correlation was found between the presence or severity of BDD and age, gender, marital status, level of education and profession. Conclusion: Considering the high prevalence of Body Dysmorphic Disorder (BDD) among rhinoplasty candidates, psychiatric evaluation is advisable before surgery to avoid unnecessary operations and patient dissatisfaction. PMID:24353539

  20. New Candidate Supernova Remnants in M31

    NASA Astrophysics Data System (ADS)

    Williams, B. F.; Schmitt, M. D.; Winkler, P. F.

    1995-05-01

    We have used pure emission-line images (deep CCD images from which a continuum image has been subtracted; see Winkler & Williams, companion paper) to search for supernova remnant (SNR) candidates in M31. The ratio of \\sii\\ lambda \\ 6724\\ to \\ha\\ is used to distinguish SNRs from \\hii\\ regions, a technique that has been used effectively in other galaxies as well as in earlier photographic surveys of M31 (D'Odorico et al 1980, A&A Supp 40, 67; Blair et al 1981, Ap J 247, 879). The extensive cooling zone typically found behind SNR shocks emits strongly in \\sii, while in photoionized material such as \\hii\\ regions most of the S is twice ionized and hence \\sii\\ is weak. SNRs almost always have \\sii/\\ha\\ ratios > 0.4\\ vs values < 0.2\\ for \\hii\\ regions. Using this criterion, we have identified 105 nebulae in M31 which are strong SNR candidates, of which 13 were previously identified by D'Odorico et al and/or Blair et al. While this number probably represents a small minorit y of the SNRs which are actually present in M31, confirmation of a substantial fraction of these would increase the population of known remnants in M31 several-fold and would make it the galaxy with the largest sample of known optical SNRs, including our own. For the cumulative number of SNRs as a function of diameter we find N(

  1. An evaluation of candidate oxidation resistant materials

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon; Banks, Bruce; Mirtich, Michael; Difilippo, Frank; Hotes, Deborah; Labed, Richard; Dever, Terese; Kussmaul, Michael

    1987-01-01

    Ground based testing of materials considered for Kapton solar array blanket protection, graphite epoxy structural member protection, and high temperature radiators was performed in an RF plasma asher. Ashing rates for Kapton were correlated with rates measured on STS-8 to determine the exposure time equivalent to one year in low Earth orbit (LEO) at a constant density space station orbital flux. Protective coatings on Kapton from Tekmat, Andus Corporation, and LeRC were evaluated in the plasma asher and mass loss rates per unit area were measured for each sample. All samples evaluated provided some protection to the underlying surface but ion beam sputter deposited samples of SiO2 and SiO2 with 8% polytetrafluoroethylene (PTFE) showed no evidence of degradation after 47 hours of exposure. Mica paint was evaluated as a protective coating for graphite epoxy structural members. Mica appears to be resistant to attack by atomic oxygen but only offers some limited protection as a paint because the paint vehicles evaluated to date were not resistant to atomic oxygen. Four materials were selected for evaluation as candidate radiator materials: stainless steel, copper, niobium-1% zirconium, and titanium-6% aluminum-4% vanadium. These materials were surface textured by various means to improve their emittance. Emittances as high as 0.93 at 2.5 microns for stainless steel and 0.89 at 2.5 microns for Nb-1 Zr were obtained from surface texturing. There were no significant changes in emittance after asher exposure.

  2. Degradation resistance of some candidate composite biomaterials.

    PubMed

    McKenna, G; Bradley, G W; Dunn, H K; Statton, W O

    1979-09-01

    The degradation resistance of matrix, fiber and composite systems which we have been studying as candidate orthopedic materials has been examined in two appropriate environments. Both resistance to steam sterilization in an autoclave environment and resistance to a simulated physiologic solution have been studied. In the autoclave study, samples were placed in a pressure cooker at 123 degrees C for differing amounts of time and tested for retention of mechanical properties. Results indicate that most of the materials tested could be autoclaved several times, as long as autoclave times did not exceed 1 hr. Longer autoclave times result in an accelerated degradation and loss of strength of all materials except the polypropylene. Polysulfone degrades after even the shortest autoclave duration. Resistance to the simulated physiologic environment was tested by measured retention of mechanical properties after immersion times in pseudo-extracellular fluid (PECF) at 37 degrees C for as long as three years. None of the materials showed any significant changes in properties after immersion in the PECF. PMID:479222

  3. IBD Candidate Genes and Intestinal Barrier Regulation

    PubMed Central

    McCole, Declan F.

    2015-01-01

    Technological advances in the large scale analysis of human genetics have generated profound insights into possible genetic contributions to chronic diseases including the inflammatory bowel diseases (IBDs), Crohn’s disease and ulcerative colitis. To date, 163 distinct genetic risk loci have been associated with either Crohn’s disease or ulcerative colitis, with a substantial degree of genetic overlap between these 2 conditions. Although many risk variants show a reproducible correlation with disease, individual gene associations only affect a subset of patients, and the functional contribution(s) of these risk variants to the onset of IBD is largely undetermined. Although studies in twins have demonstrated that the development of IBD is not mediated solely by genetic risk, it is nevertheless important to elucidate the functional consequences of risk variants for gene function in relevant cell types known to regulate key physiological processes that are compromised in IBD. This article will discuss IBD candidate genes that are known to be, or are suspected of being, involved in regulating the intestinal epithelial barrier and several of the physiological processes presided over by this dynamic and versatile layer of cells. This will include assembly and regulation of tight junctions, cell adhesion and polarity, mucus and glycoprotein regulation, bacterial sensing, membrane transport, epithelial differentiation, and restitution. PMID:25215613

  4. Genetic markers: Potential candidates for cardiovascular disease.

    PubMed

    Rather, Riyaz Ahmad; Dhawan, Veena

    2016-10-01

    The effective prevention of cardiovascular disease depends upon the ability to recognize the high-risk individuals at an early stage of the disease or long before the development of adverse events. Evolving technologies in the fields of proteomics, metabolomics, and genomics have played a significant role in the discovery of cardiovascular biomarkers, but so far these methods have achieved the modest success. Hence, there is a crucial need for more reliable, suitable, and lasting diagnostic and therapeutic markers to screen the disease well in time to start the clinical aid to the patients. Gene polymorphisms associated with the cardiovascular disease play a decisive role in the disease onset. Therefore, the genetic marker evaluation to classify high-risk patients from low-risk patients trends an effective approach to patient management and care. Currently, there are no genetic markers available for extensive adoption as risk factors for coronary vascular disease, yet, there are numerous promising, biologically acceptable candidates. Many of these gene biomarkers, alone or in combination, can play an essential role in the prediction of cardiovascular risk. The present review highlights some putative emerging genetic biomarkers that could facilitate more authentic and fast diagnosis of CVD. This review also briefly describes few technological approaches employed in the biomarker search. PMID:27416153

  5. Polysaccharides: Candidates of promising vaccine adjuvants.

    PubMed

    Li, Pingli; Wang, Fengshan

    2015-04-01

    Aluminium-based adjuvants remain the only adjuvants approved for human use in the USA for over 80 years because of alum's simplicity, tolerability, safety and cost-efficiency. Recent development of vaccines, especially the increasing applications of recombinant subunit and synthetic vaccines, makes aluminium adjuvants cannot stimulate enough immunity to the antigens, since aluminium adjuvants can only induce Th2 type immune responses. So, novel adjuvants are urgent to make up the disadvantages of aluminium adjuvants. However, some major hurdles need to be overcome, not only the scientific knowledge of adjuvants but also unacceptable side-effects and toxicity. A number of carbohydrate-based polysaccharides from plant, bacterial, yeast and synthetic sources can act as pathogen-associated molecular patterns (PAMPs) and recognize pattern recognition receptors (PRRs) on immune cells, followed by triggering innate immunity and regulating adaptive immunity. What is more, polysaccharides are safe and biodegradable without tissue deposits as observed in aluminium adjuvants. Therefore, polysaccharide-based compounds and formulations are potential vaccine adjuvant candidates. Here, we mainly review polysaccharide-based adjuvants investigated in recent years. PMID:25994059

  6. Virus-like particles as nanovaccine candidates

    NASA Astrophysics Data System (ADS)

    Guillen, G.; Aguilar, J. C.; Dueñas, S.; Hermida, L.; Iglesias, E.; Penton, E.; Lobaina, Y.; Lopez, M.; Mussachio, A.; Falcon, V.; Alvarez, L.; Martinez, G.; Gil, L.; Valdes, I.; Izquierdo, A.; Lazo, L.; Marcos, E.; Guzman, G.; Muzio, V.; Herrera, L.

    2013-03-01

    The existing vaccines are mainly limited to the microorganisms we are able to culture and produce and/or to those whose killing is mediated by humoral response (antibody mediated). It has been more difficult to develop vaccines capable of inducing a functional cellular response needed to prevent or cure chronic diseases. New strategies should be taken into account in the improvement of cell-based immune responses in order to prevent and control the infections and eventually clear the virus. Preclinical and clinical results with vaccine candidates developed as a vaccine platform based on virus-like particles (VLPs) evidenced their ability to stimulate mucosal as well as systemic immunity. Particles based on envelope, membrane or nucleocapsid microbial proteins induce a strong immune response after nasal or parenteral administration in mice, non-human primates and humans. In addition, the immune response obtained was modulated in a Th1 sense. The VLPs were also able to immunoenhance the humoral and cellular immune responses against several viral pathogens. Studies in animals and humans with nasal and systemic formulations evidenced that it is possible to induce functional immune response against HBV, HCV, HIV and dengue virus. Invited talk at the 6th International Workshop on Advanced Materials Science and Nanotechnology, 30 October - 2 November 2012, Ha Long, Vietnam.

  7. Ailing Voters Advance Attractive Congressional Candidates

    PubMed Central

    Franklin, Robert G.; Palumbo, Rocco

    2015-01-01

    Among many benefits of facial attractiveness, there is evidence that more attractive politicians are more likely to be elected. Recent research found this effect to be most pronounced in congressional districts with high disease threat—a result attributed to an adaptive disease avoidance mechanism, whereby the association of low attractiveness with poor health is particularly worrisome to voters who feel vulnerable to disease. We provided a more direct test of this explanation by examining the effects of individuals’ own health and age. Supporting a disease avoidance mechanism, less healthy participants showed a stronger preference for more attractive contenders in U.S. Senate races than their healthier peers, and this effect was stronger for older participants, who were generally less healthy than younger participants. Stronger effects of health for older participants partly reflected the absence of positive bias toward attractive candidates among the healthiest, suggesting that healthy older adults may be unconcerned about disease threat or sufficiently wise to ignore attractiveness. PMID:25562113

  8. New optical nova candidate in M 31

    NASA Astrophysics Data System (ADS)

    Pietsch, W.; Henze, M.; Burwitz, V.; Kaur, A.; Hartmann, D. H.; Milne, P.; Williams, G.

    2010-12-01

    We report the discovery of a possible nova in M 31 on a 12x60s stacked R filter CCD image obtained with the robotic 60cm telescope with an E2V CCD (2kx2k, 13.5 micron sq. pixels) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA) on 2010 December 11.095 UT with magnitude of 16.6. The object is visible on all individual images. The position for the nova candidate is RA = 00h42m31.08s, Dec = +41d27'20.3"(J2000, accuracy of 0.3"), which is 149" west and 672" north of the core of M 31. We do not detect the object on a 4x60s stacked SLOTIS CCD image obtained on2010 December 5.213 UT (limiting R magnitude at the position of 19.0). There is no entry in VizieR/CDS for this object and no minor planet could be found on this position using the MPC/IAU Minor Planet Checker (see http://scully.harvard.edu/~cgi/CheckMP) . All magnitudes given are obtained from a photometric solution using R magnitudes of the Local Group Survey M 31 catalogue (Massey et al.

  9. Spectroscopic observations of cool degenerate star candidates

    NASA Technical Reports Server (NTRS)

    Hintzen, P.

    1986-01-01

    Spectroscopic observations are reported for 23 Luyten Half-Second degenerate star candidates and for 13 Luyten-Palomar common proper-motion pairs containing possible degenerate star components. Twenty-five degenerate stars are identified, 20 of which lack previous spectroscopy. Most of these stars are cool - Luyten color class g or later. One star, LP 77-57, shows broad continuum depressions similar to those in LHS 1126, which Liebert and Dahn attributed to pressure-shifted C2. A second degenerate star, LHS 290, exhibits apparent strong Swan bands which are blueshifted about 75 A. Further observations, including polarimetry and photometry, are required to appraise the spectroscopic peculiarities of these stars. Finally, five cool, sharp-lined DA white dwarfs have been observed to detect lines of metals and to determine line strengths. None of these DAs show signs of Mg b or the G band, and four show no evidence of Ca II K. The attempt to detect Ca MI in the fifth star, G199-71, was inconclusive.

  10. Comet candidates among quasi-Hilda objects

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, R.; García-Migani, E.

    2016-05-01

    Aims: We present the results of a search for quasi-Hilda comets. We wanted to find objects that have recently arrived from the Centaur zone that could became active near the perihelion of their orbits. Methods: Two hundred and seventy-seven objects from the ASTORB database were selected following a dynamical criteria to constrain the unstable quasi-Hilda region. These objects were integrated backward 50 000 yr in order to identify those that have recently arrived from the outer regions of the solar system. Results: The backward integration showed that 11 objects could be Centaurs or transneptunian objects that ended their dynamical evolution as quasi-Hilda comets. The dynamical evolution of these objects from a statistical point of view was studied by computing the time-averaged distribution of a number of clones as a function of the aphelion and perihelion distances. All the candidates show a dynamical behavior that is expected for comets injected in the inner solar system from the Centaur or transneptunian regions and reaching the quasi-Hilda region.

  11. Galactic worms. I - Catalog of worm candidates

    NASA Technical Reports Server (NTRS)

    Koo, Bon-Chul; Heiles, Carl; Reach, William T.

    1992-01-01

    A catalog of candidates for the Galactic worms that are possibly the walls surrounding the superbubbles is compiled; 118 isolated structures that appear both in H I and in IR (60 and 100 microns). Fifty-two are possibly associated with H II regions. It is found that the 100-micron emissivity increases systematically toward the Galactic interior, which is consistent with the increase of the general interstellar radiation field. The 100-micron emissivity of the structures associated with the H II regions is larger than that of the structures without associated H II regions. The 60-100-micron ratio is large, 0.28 +/- 0.03, which may indicate that the grains associated with the atomic gas have a relatively large population of small grains. Thirty-five structures appear in the 408-MHz continuum. The IR and the radio continuum properties suggest that the 408-MHz continuum emission in those structures is very likely thermal. The implications of these results on the ionization of gas far from the Galactic plane are discussed.

  12. ARCHITECTURE AND DYNAMICS OF KEPLER'S CANDIDATE MULTIPLE TRANSITING PLANET SYSTEMS

    SciTech Connect

    Lissauer, Jack J.; Jenkins, Jon M.; Borucki, William J.; Bryson, Stephen T.; Howell, Steve B.; Ragozzine, Darin; Holman, Matthew J.; Carter, Joshua A.; Fabrycky, Daniel C.; Fortney, Jonathan J.; Steffen, Jason H.; Ford, Eric B.; Shporer, Avi; Rowe, Jason F.; Quintana, Elisa V.; Caldwell, Douglas A.; Ciardi, David; Gautier, Thomas N. III; and others

    2011-11-01

    About one-third of the {approx}1200 transiting planet candidates detected in the first four months of Kepler data are members of multiple candidate systems. There are 115 target stars with two candidate transiting planets, 45 with three, 8 with four, and 1 each with five and six. We characterize the dynamical properties of these candidate multi-planet systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean-motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. We find that virtually all candidate systems are stable, as tested by numerical integrations that assume a nominal mass-radius relationship. Several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Using the observed multiplicity frequencies, we find that a single population of planetary systems that matches the higher multiplicities underpredicts the number of singly transiting systems. We provide constraints on the true multiplicity and mutual inclination distribution of the multi-candidate systems, revealing a population of systems with multiple super-Earth-size and Neptune-size planets with low to moderate mutual inclinations.

  13. Candidate Gene Associations to Withdrawn Behavior

    PubMed Central

    Rubin, David H.; Althoff, Robert R.; Ehli, Erik A.; Davies, Gareth E.; Rettew, David C.; Crehan, Eileen T.; Walkup, John T.; Hudziak, James J.

    2013-01-01

    BACKGROUND Social withdrawal is a core neuropsychiatric phenomenon in developmental psychopathology. Its presence predicts psychopathology across many domains, including depression, psychosis, autism, anxiety, and suicide. Withdrawn behavior is highly heritable, persistent, and characteristically worsens without intervention. To date, few studies have successfully identified genetic associations with withdrawn behavior, despite the abundance of evidence of its heritability. This may be due to reliance of categorical over dimensional measures of the behaviorally inhibited phenotype. The aim of this study is to identify associations between known psychiatric candidate genes and a dimensionally derived measure of withdrawn behavior. METHODS Genetic information was collected on 20 Single-nucleotide Polymorphisms (SNPs) from a custom-designed SNP chip and TAQMAN arrays of 4 Variable Number of Tandem Repeat (VNTR) genes for 551 individuals from 187 families. Linear mixed modeling was employed to examine the relationship between genotypes of interest and Child Behavior Checklist (CBCL) Withdrawn Behavior Subscale Score (WBS) while controlling for gender and age through multiple linear regressions. RESULTS Withdrawn behavior was highly associated with polymorphism rs6314 of the Serotonin Receptor 2A (HTR2A) [p = 0.009, estimate = 0.310 (bootstrap 95% CI 0.155 – 0.448), bootstrap p = 0.001)] and rs1800544 of the Alpha 2 Adrenergic (ADRA2A) [p = 0.001, estimate = - 0.310 (bootstrap 95% CI -0.479 – -0.126), bootstrap p = 0.001)] genes after correction for gender and age. The association between withdrawn behavior and ADRA2A was stronger for younger children. CONCLUSIONS HTR2A and ADRA2A genes are associated with withdrawn behavior. This reinforces the role of catecholaminergic genes in the heritability of withdrawn behavior. PMID:23808549

  14. On improving the credibility of candidate gene studies: A review of candidate gene studies published in Emotion.

    PubMed

    Okbay, Aysu; Rietveld, Cornelius A

    2015-08-01

    The discovery of genetic variants associated with psychological traits deepens our knowledge about causes and consequences of individual differences. In psychology, the standard approach to identify these variants is the "candidate gene study." In a candidate gene study, a limited set of genetic variants is selected based on their hypothesized or known biological function, and these variants are tested for association with the psychological trait of interest. The successful replication of published candidate gene studies, however, is alarmingly scarce. In this article we describe the challenges to successfully identifying genetic associations, and review the candidate gene studies published in Emotion. We conclude that the implementation of 4 methodological guidelines developed by the Behavior Genetics Association for evaluating candidate gene studies will help to increase the credibility of candidate gene study findings. PMID:26214572

  15. GRAVITATIONAL LENS CANDIDATES IN THE E-CDFS

    SciTech Connect

    More, A.; More, S.; Jahnke, K.; Gallazzi, A.; Bell, E. F.; Barden, M.; Haeussler, B.

    2011-06-10

    We report 10 lens candidates in the Extended Chandra Deep Field South from the GEMS survey. Nine of the systems are new detections and only one of the candidates is a known lens system. For the most promising five systems including the known lens system, we present results from preliminary lens mass modeling, which tests if the candidates are plausible lens systems. Photometric redshifts of the candidate lens galaxies are obtained from the COMBO-17 galaxy catalog. Stellar masses of the candidate lens galaxies within the Einstein radius are obtained by using the z-band luminosity and the V-z color-based stellar mass-to-light ratios. As expected, the lensing masses are found to be larger than the stellar masses of the candidate lens galaxies. These candidates have similar dark matter fractions as compared to lenses in SLACS and COSMOS. They also roughly follow the halo-mass-stellar-mass relation predicted by the subhalo abundance matching technique. One of the candidate lens galaxies qualifies as a luminous infrared galaxy and may not be a true lens because the arc-like feature in the system is likely to be an active region of star formation in the candidate lens galaxy. Among the five best candidates, one is a confirmed lens system, one is likely a lens system, two are less likely to be lenses, and the status of one of the candidates is ambiguous. Spectroscopic follow-up of these systems is still required to confirm lensing and/or for more accurate determination of the lens masses and mass density profiles.

  16. Spectroscopic distances of 28 nearby star candidates

    NASA Astrophysics Data System (ADS)

    Jahreiß, H.; Meusinger, H.; Scholz, R.-D.; Stecklum, B.

    2008-06-01

    Aims: Twenty eight hitherto neglected candidates for the Catalogue of Nearby Stars (CNS) were investigated to verify their classification and to improve their distance estimates. All targets had at least a preliminary status of being nearby dwarf stars based on their large proper motions and relatively faint magnitudes. Better photometric and/or spectroscopic distances were required for selecting stars for further trigonometric parallax measurements. Methods: Low-resolution spectra were obtained with NASPEC at the Tautenburg 2 m telescope and with CAFOS at the Calar Alto 2.2 m telescope. The spectral types of M-type stars were determined by direct comparison of the target's spectra with those of comparison stars of known spectral types observed with the same instrument. The classification of earlier types was performed based on comparison with published spectral libraries. Results: For most of the target stars reliable spectral types could be determined and in combination with 2MASS photometry new improved distance estimates became available. The majority were classified as M dwarfs including 11 stars within 25 pc. The fainter component of LDS 1365, previously thought to form a nearby common proper motion pair, is according to our results an unrelated high-velocity background star. For several other nearby common proper motion pairs our distance estimates of the fainter components are in good agreement with Hipparcos distances of the brighter components. The three stars in our sample that were previously thought to be white dwarfs (GJ 2091, GJ 2094, GJ 2098) turned out to be more distant high-velocity F- to K-type (sub)dwarfs. For the star with the largest tangential velocity (GJ 2091; v_ tan>500 km s-1) we have additional evidence for its probable Galactic halo membership from a measured large radial velocity of 266 ± 25 km s-1 and from its UBV photometry indicating a low metallicity. Based on observations with the 2 m telescope of the Thüringer Landessternwarte

  17. Evolution and magnitudes of candidate Planet Nine

    NASA Astrophysics Data System (ADS)

    Linder, Esther F.; Mordasini, Christoph

    2016-04-01

    Context. The recently renewed interest in a possible additional major body in the outer solar system prompted us to study the thermodynamic evolution of such an object. We assumed that it is a smaller version of Uranus and Neptune. Aims: We modeled the temporal evolution of the radius, temperature, intrinsic luminosity, and the blackbody spectrum of distant ice giant planets. The aim is also to provide estimates of the magnitudes in different bands to assess whether the object might be detectable. Methods: Simulations of the cooling and contraction were conducted for ice giants with masses of 5, 10, 20, and 50 M⊕ that are located at 280, 700, and 1120 AU from the Sun. The core composition, the fraction of H/He, the efficiency of energy transport, and the initial luminosity were varied. The atmospheric opacity was set to 1, 50, and 100 times solar metallicity. Results: We find for a nominal 10 M⊕ planet at 700 AU at the current age of the solar system an effective temperature of 47 K, much higher than the equilibrium temperature of about 10 K, a radius of 3.7 R⊕, and an intrinsic luminosity of 0.006 L♃. It has estimated apparent magnitudes of Johnson V, R, I, L, N, Q of 21.7, 21.4, 21.0, 20.1, 19.9, and 10.7, and WISE W1-W4 magnitudes of 20.1, 20.1, 18.6, and 10.2. The Q and W4 band and other observations longward of about 13 μm pick up the intrinsic flux. Conclusions: If candidate Planet 9 has a significant H/He layer and an efficient energy transport in the interior, then its luminosity is dominated by the intrinsic contribution, making it a self-luminous planet. At a likely position on its orbit near aphelion, we estimate for a mass of 5, 10, 20, and 50 M⊕ a V magnitude from the reflected light of 24.3, 23.7, 23.3, and 22.6 and a Q magnitude from the intrinsic radiation of 14.6, 11.7, 9.2, and 5.8. The latter would probably have been detected by past surveys.

  18. Sensitive radio survey of obscured quasar candidates

    NASA Astrophysics Data System (ADS)

    Alexandroff, Rachael M.; Zakamska, Nadia L.; van Velzen, Sjoert; Greene, Jenny E.; Strauss, Michael A.

    2016-08-01

    We study the radio properties of moderately obscured quasars in samples at both low (z ˜ 0.5) and high (z ˜ 2.5) redshift to understand the role of radio activity in accretion, using the Karl G. Jansky Very Large Array (VLA) at 6.0GHz and 1.4GHz. Our z ˜ 2.5 sample consists of optically-selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of νLν[1.4 GHz]⪉ 10^{40} erg s-1. Only a single source is individually detected in our deep (rms˜10 μJy) exposures. This population would not be identified by radio-based selection methods used for distinguishing dusty star-forming galaxies and obscured active nuclei. In our pilot A-array study of z ˜ 0.5 radio-quiet quasars, we spatially resolve four of five objects on scales ˜5 kpc and find they have steep spectral indices with an average value of α = -0.75. Therefore, radio emission in these sources could be due to jet-driven or radiatively driven bubbles interacting with interstellar material on the scale of the host galaxy. Finally, we also study the additional population of ˜200 faint (˜40μJy - 40mJy) field radio sources observed over ˜120 arcmin2 of our data. 60% of these detections (excluding our original targets) are matched in the Sloan Digital Sky Survey (SDSS) and/or Wide-Field Infrared Survey Explorer (WISE) and are, in roughly equal shares, active galactic nuclei (AGN) at a broad range of redshifts, passive galaxies with no other signs of nuclear activity and infrared-bright but optically faint sources. Spectroscopically or photometrically confirmed star-forming galaxies constitute only a small minority of the matches. Such sensitive radio surveys allow us to address important questions of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.

  19. Evolution and magnitudes of candidate Planet Nine

    NASA Astrophysics Data System (ADS)

    Linder, Esther F.; Mordasini, Christoph

    2016-05-01

    Context. The recently renewed interest in a possible additional major body in the outer solar system prompted us to study the thermodynamic evolution of such an object. We assumed that it is a smaller version of Uranus and Neptune. Aims: We modeled the temporal evolution of the radius, temperature, intrinsic luminosity, and the blackbody spectrum of distant ice giant planets. The aim is also to provide estimates of the magnitudes in different bands to assess whether the object might be detectable. Methods: Simulations of the cooling and contraction were conducted for ice giants with masses of 5, 10, 20, and 50 M⊕ that are located at 280, 700, and 1120 AU from the Sun. The core composition, the fraction of H/He, the efficiency of energy transport, and the initial luminosity were varied. The atmospheric opacity was set to 1, 50, and 100 times solar metallicity. Results: We find for a nominal 10 M⊕ planet at 700 AU at the current age of the solar system an effective temperature of 47 K, much higher than the equilibrium temperature of about 10 K, a radius of 3.7 R⊕, and an intrinsic luminosity of 0.006 L♃. It has estimated apparent magnitudes of Johnson V, R, I, L, N, Q of 21.7, 21.4, 21.0, 20.1, 19.9, and 10.7, and WISE W1-W4 magnitudes of 20.1, 20.1, 18.6, and 10.2. The Q and W4 band and other observations longward of about 13 μm pick up the intrinsic flux. Conclusions: If candidate Planet 9 has a significant H/He layer and an efficient energy transport in the interior, then its luminosity is dominated by the intrinsic contribution, making it a self-luminous planet. At a likely position on its orbit near aphelion, we estimate for a mass of 5, 10, 20, and 50 M⊕ a V magnitude from the reflected light of 24.3, 23.7, 23.3, and 22.6 and a Q magnitude from the intrinsic radiation of 14.6, 11.7, 9.2, and 5.8. The latter would probably have been detected by past surveys.

  20. Is there a blackhole among the black-hole candidates?

    NASA Astrophysics Data System (ADS)

    Kundt, Wolfgang; Fischer, Daniel

    1989-03-01

    None of the tentative black-hole identifications has remained without serious difficulties. As a class, the black-hole candidates differ in no obvious property from neutron-star binaries other than in their estimated high mass. An interpretation of the black-hole candidates as binary neutron stars surrounded by a more or less massive accretion disk is favored.

  1. Primary-Grade Teacher Candidates' Views on Museum Education

    ERIC Educational Resources Information Center

    Tas, Ayse Mentis

    2012-01-01

    This study identifies the primary-grade teacher candidates' views on museum education. The research is a descriptive research that used survey model. The study group is made up of 209 primary-grade teacher candidates who were seniors in the Primary-Grade Teaching Program. They were all attending Konya University's Faculty of Education. A survey…

  2. 32 CFR 903.8 - Cadet candidate disenrollment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Cadet candidate disenrollment. 903.8 Section 903.8 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE MILITARY TRAINING AND SCHOOLS AIR FORCE ACADEMY PREPARATORY SCHOOL § 903.8 Cadet candidate disenrollment. (a) In accordance with AFI 36-3208, the Commander, HQ...

  3. Opinions of Counselor Candidates Regarding Counseling Skills Training

    ERIC Educational Resources Information Center

    Aladag, Mine; Yaka, Baris; Koç, Ismet

    2014-01-01

    The aim of this study is to contribute to the enhancement of the quality of counseling skills training and counselor education through the medium of understanding the opinions of counselor candidates regarding counseling skills training. The research group consisted of 67 counselor candidates who voluntarily participated in the study. The research…

  4. Shaping Teacher Candidates' Digital Portfolios: What Administrators Want for Hiring

    ERIC Educational Resources Information Center

    Snoeyink, Rick; Meyer, Joy

    2007-01-01

    This qualitative study investigated P-12 school administrators' perceptions of teacher education candidates' online digital portfolios for hiring purposes. Over the course of three semesters, focus group interviews and an online questionnaire gauged administrators' perceptions of selected candidates' portfolios and how they might be used to help…

  5. Educational Leadership Preparation: What Supervisors, Candidates, and Mentors Said

    ERIC Educational Resources Information Center

    Tubbs, J. Eric; Holliday, H. E.

    2009-01-01

    The findings of this study identified practicum areas that meet the educational demands of candidates while highlighting practicum areas that need improvement. The study contributes to the knowledge base of the field by drawing upon feedback from university supervisors, school mentors and program candidates to evaluate and improve the practicum…

  6. 29 CFR 452.31 - One candidate for several offices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false One candidate for several offices. 452.31 Section 452.31... AND DISCLOSURE ACT OF 1959 Frequency and Kinds of Elections § 452.31 One candidate for several offices... perform the functions of more than one office, a separate election need not be held for each office....

  7. Investigating Academic Achievements and Critical Thinking Dispositions of Teacher Candidates

    ERIC Educational Resources Information Center

    Karagöl, Ibrahim; Bekmezci, Sinan

    2015-01-01

    The aim of this study is to examine the relationship between academic achievements and critical thinking dispositions of teacher candidates in Faculty of Education and to find out whether critical thinking dispositions and academic achievements scores of teacher candidates differ according to different variables. The population consists of the…

  8. Assessing Student Teaching Experiences: Teacher Candidates' Perceptions of Preparedness

    ERIC Educational Resources Information Center

    Lee, Joohi; Tice, Kathleen; Collins, Denise; Brown, Amber; Smith, Cleta; Fox, Jill

    2012-01-01

    The purpose of this study is to investigate the effectiveness of student teaching experiences by measuring teacher candidates' perceptions of their preparedness. The participants were 130 teacher candidates who had completed their student teaching as part of a program preparing them to teach children in pre-K through grade 4. Teacher candidates…

  9. Teacher Candidate Technology Integration: For Student Learning or Instruction?

    ERIC Educational Resources Information Center

    Clark, Cynthia; Zhang, Shaoan; Strudler, Neal

    2015-01-01

    Transfer of instructional technology knowledge for student-centered learning by teacher candidates is investigated in this study. Using the transfer of learning theoretical framework, a mixed methods research design was employed to investigate whether secondary teacher candidates were able to transfer the instructional technology knowledge for…

  10. Becoming Culturally Responsive: A Need for Preservice Teacher Candidates

    ERIC Educational Resources Information Center

    Imler, Sylvia J.

    2009-01-01

    Teacher education programs are preparing more homogeneous preservice teacher candidates, whereas students in the United States are becoming more diverse. In this article, I describe how 283 preservice teacher candidates gathered responses from interviews with 283 certified teachers (special and general education) during a clinical field…

  11. 11 CFR 103.4 - Vice Presidential candidate campaign depositories.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 11 Federal Elections 1 2011-01-01 2011-01-01 false Vice Presidential candidate campaign depositories. 103.4 Section 103.4 Federal Elections FEDERAL ELECTION COMMISSION GENERAL CAMPAIGN DEPOSITORIES (2 U.S.C. 432(h)) § 103.4 Vice Presidential candidate campaign depositories. Any campaign depository designated by the principal campaign committee...

  12. Chemical Literacy Levels of Science and Mathematics Teacher Candidates

    ERIC Educational Resources Information Center

    Celik, Suat

    2014-01-01

    The goal of this study was to investigate Turkish science and mathematics teacher candidates' levels of attainment in chemical literacy. These candidates had all studied the new Turkish chemistry curriculum in high school. The sample of the study consisted of 112 students, who were first-year students in the Department of Secondary Science…

  13. 14 CFR 91.321 - Carriage of candidates in elections.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Carriage of candidates in elections. 91.321 Section 91.321 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... State or local law and those terms relate to candidates for election to public office in State and...

  14. Experimental evaluation of candidate graphical microburst alert displays

    NASA Technical Reports Server (NTRS)

    Wanke, Craig; Hansman, R. John

    1992-01-01

    The topics addressed are: (1) experimental evaluation of candidate graphical microburst displays; (2) microburst detection and alerting; (3) previous part-task simulator experiment-comparison of presentation modes; (4) presentation mode comparison-results; (5) advantages of graphical mode of presentation; (6) graphical microburst alert experiment-objectives; and graphical microburst alert experiment-overview; and (7) candidate display design.

  15. Facebook Connection Styles among Physical Education Teacher Candidates

    ERIC Educational Resources Information Center

    Erdogdu, Murat

    2016-01-01

    The purpose of this study is to determine the Facebook connection styles of physical education (PE) teacher candidates. The participants were composed of 626 (age = 21.21 ± 2.024) physical education teacher candidates from the departments of Physical Education and Sports. They teach in five different universities. It was done in 2014-2015 academic…

  16. Fostering the Development of Chemistry Teacher Candidates: A Bioecological Approach

    ERIC Educational Resources Information Center

    Lewthwaite, Brian; Wiebe, Rick

    2012-01-01

    This ongoing research inquiry investigates through the analysis of teacher candidate experiences the factors influencing two groups of chemistry teacher candidates' development during their extended practica in their second and final year of an after-degree bachelor of education at a university in central Canada. The tenets of Bronfenbrenner's…

  17. Writing Instruction for Teacher Candidates: Strengthening a Weak Curricular Area

    ERIC Educational Resources Information Center

    Grisham, Dana L.; Wolsey, Thomas Devere

    2011-01-01

    In this case study, two teacher educators in literacy examined teacher candidates' (N = 24) learning of writing instruction across a three-course sequence of literacy methods. Data collected included a survey of candidates' knowledge of writing instruction, their formal observations of writing lessons in their student-teaching placements, a…

  18. Teacher Candidates' Views of Digital Games as Learning Devices

    ERIC Educational Resources Information Center

    Sardone, Nancy B.; Devlin-Scherer, Roberta

    2009-01-01

    The objective of this research study was to explore teacher candidate views toward digital learning games using an immersive strategy. Specifically, we were interested in finding out what game use in classroom settings taught candidates about the role of teacher as facilitator of instruction. The procedures first focused teacher candidate…

  19. Academic Self-Efficacy Perceptions of Teacher Candidates

    ERIC Educational Resources Information Center

    Yesilyurt, Etem

    2013-01-01

    This study aims determining academic self-efficacy perception of teacher candidates. It is survey model. Population of the study consists of teacher candidates in 2010-2011 academic years at Ahmet Kelesoglu Education Faculty of Education Formation of Selcuk University. A simple random sample was selected as sampling method and the study was…

  20. 15 CFR 922.21 - Selection of active candidates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Selection of active candidates. 922.21...) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE... Selection of active candidates. (a) The Secretary shall, from time to time, select a limited number of...

  1. 14 CFR 1214.1106 - Selection of astronaut candidates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Selection of astronaut candidates. 1214.1106 Section 1214.1106 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT NASA Astronaut Candidate Recruitment and Selection Program § 1214.1106 Selection of...

  2. 14 CFR 1214.1106 - Selection of astronaut candidates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Selection of astronaut candidates. 1214.1106 Section 1214.1106 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT NASA Astronaut Candidate Recruitment and Selection Program § 1214.1106 Selection of...

  3. 14 CFR § 1214.1106 - Selection of astronaut candidates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Selection of astronaut candidates. § 1214.1106 Section § 1214.1106 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT NASA Astronaut Candidate Recruitment and Selection Program § 1214.1106 Selection of...

  4. 14 CFR 1214.1106 - Selection of astronaut candidates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Selection of astronaut candidates. 1214.1106 Section 1214.1106 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT NASA Astronaut Candidate Recruitment and Selection Program § 1214.1106 Selection of...

  5. Teacher Candidates' Perceptions of Technology Supported Literacy Practices

    ERIC Educational Resources Information Center

    Wake, Donna; Whittingham, Jeff

    2013-01-01

    This study explores teacher education candidates' perceptions of technologies used to support K-12 student literacy development. Candidates scored each technology based on their impressions of its ability to support student literacy development. They also evaluated their own level of expertise with each piece of technology using a pre-post…

  6. MAT@USC Candidates and Latino English Language Learners

    ERIC Educational Resources Information Center

    Lomeli, Cynthia Leticia

    2012-01-01

    The purpose of this study was to further understand the perceptions of MAT@USC teacher candidates and how their perceptions and previous experiences affect the educational experiences of Latino English language learners. Three questions were developed to guide this study: (1) What are the perceptions of MAT@USC candidates in selected courses…

  7. 11 CFR 110.10 - Expenditures by candidates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... PROHIBITIONS § 110.10 Expenditures by candidates. Except as provided in 11 CFR parts 9001, et seq. and 9031, et... 11 CFR 100.33. ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Expenditures by candidates. 110.10 Section...

  8. Screening Teacher Candidates: Luck of the Draw or Objective Selection?

    ERIC Educational Resources Information Center

    Bolz, Anthony James

    2009-01-01

    This study was an attempt to gain an understanding of what tools and strategies elementary school administrators in Wisconsin use to screen teacher candidates during the hiring process. The results were analyzed to determine the extent to which administrators are screening for characteristics of candidates that predict success in the classroom. …

  9. Mathematics Teacher Candidates' Metaphors about the Concept of "Mathematics"

    ERIC Educational Resources Information Center

    Erdogan, Ahmet; Yazlik, Derya Ozlem; Erdik, Cengiz

    2014-01-01

    The main purpose of this study was to research mathematics teacher candidates' perceptions about the concept of "mathematics" through the use of metaphors. The research is conducted during 2012-2013 academic year, on a group of 111 mathematics teacher candidates at the Education Faculty of a University in Turkey. To collect the research…

  10. Social Studies Teacher Candidates' Views on Historical Thinking Skills

    ERIC Educational Resources Information Center

    Ozmen, Cengiz

    2015-01-01

    Current study aimed to present Social Studies teacher candidates' views on historical thinking skills. Study was conducted using qualitative design and working group was composed of a total of 121 teacher candidates (62 females and 59 males) attending Social Studies Teaching Department of Karadeniz Technical University and Adiyaman University…

  11. University Offer Rates for Candidates from Different Ethnic Categories

    ERIC Educational Resources Information Center

    Noden, Philip; Shiner, Michael; Modood, Tariq

    2014-01-01

    Previous research suggested that candidates from some black and minority ethnic groups were less likely to receive an offer of a place from an "old" university. These findings were disputed in a re-analysis carried out for HEFCE which found that only Pakistani candidates were significantly less likely to receive offers (from both…

  12. Developing Benchmarks to Measure Teacher Candidates' Performance

    ERIC Educational Resources Information Center

    Frazier, Laura Corbin; Brown-Hobbs, Stacy; Palmer, Barbara Martin

    2013-01-01

    This paper traces the development of teacher candidate benchmarks at one liberal arts institution. Begun as a classroom assessment activity over ten years ago, the benchmarks, through collaboration with professional development school partners, now serve as a primary measure of teacher candidates' performance in the final phases of the…

  13. Pathogenic Network Analysis Predicts Candidate Genes for Cervical Cancer

    PubMed Central

    Zhang, Yun-Xia

    2016-01-01

    Purpose. The objective of our study was to predicate candidate genes in cervical cancer (CC) using a network-based strategy and to understand the pathogenic process of CC. Methods. A pathogenic network of CC was extracted based on known pathogenic genes (seed genes) and differentially expressed genes (DEGs) between CC and normal controls. Subsequently, cluster analysis was performed to identify the subnetworks in the pathogenic network using ClusterONE. Each gene in the pathogenic network was assigned a weight value, and then candidate genes were obtained based on the weight distribution. Eventually, pathway enrichment analysis for candidate genes was performed. Results. In this work, a total of 330 DEGs were identified between CC and normal controls. From the pathogenic network, 2 intensely connected clusters were extracted, and a total of 52 candidate genes were detected under the weight values greater than 0.10. Among these candidate genes, VIM had the highest weight value. Moreover, candidate genes MMP1, CDC45, and CAT were, respectively, enriched in pathway in cancer, cell cycle, and methane metabolism. Conclusion. Candidate pathogenic genes including MMP1, CDC45, CAT, and VIM might be involved in the pathogenesis of CC. We believe that our results can provide theoretical guidelines for future clinical application. PMID:27034707

  14. EXPLORING THE HABITABLE ZONE FOR KEPLER PLANETARY CANDIDATES

    SciTech Connect

    Kaltenegger, L.; Sasselov, D.

    2011-08-01

    This Letter outlines a simple approach to evaluate habitability of terrestrial planets by assuming different types of planetary atmospheres and using corresponding model calculations. Our approach can be applied for current and future candidates provided by the Kepler mission and other searches. The resulting uncertainties and changes in the number of planetary candidates in the HZ for the Kepler 2011 February data release are discussed. To first order, the HZ depends on the effective stellar flux distribution in wavelength and time, the planet albedo, and greenhouse gas effects. We provide a simple set of parameters which can be used for evaluating future planet candidates from transit searches.

  15. Novel low profile antenna candidates for EHF portable terminals

    NASA Technical Reports Server (NTRS)

    Roscoe, D.; Shafai, L.; Ittipiboon, A.; Cuhaci, M.; Moheb, H.

    1995-01-01

    This paper presents three low profile antenna candidates for EHF portable communication terminals. The first structure is a planar, multilayer microstrip antenna utilizing electromagnetic coupling to minimize the complexity and losses associated with the feed network. The second candidate is a medium gain (15 dB) radiating cavity antenna utilizing a thick metallic ground plane. This element is amenable to device integration because a heat sink is incorporated and an area is available for fastening modular RF components. Thirdly, as an alternative to microstrip antennas, dielectric resonator antennas (DRA's) are presented. A broadband (28 percent) DRA is discussed. Experimental measurements are presented for all three antenna candidates.

  16. Official portrait of 1987 astronaut candidate Bruce E. Melnick

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Official portrait of 1987 astronaut candidate Bruce E. Melnick. Melnick, a member of the United States Coast Guard (USCG) and Astronaut Class 12, wears navy blue flight suit and holds space shuttle orbiter model.

  17. 11 CFR 100.148 - Volunteer activity for candidate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... stickers, handbills, brochures, posters, and yard signs) is not an expenditure on behalf of such...

  18. Single Event Effects Results for Candidate Spacecraft Electronics for NASA

    NASA Technical Reports Server (NTRS)

    O'Bryan, Martha; LaBel, Kenneth A.; Kniffin, Scott D.; Howard, James W., Jr.; Poivey, Christian; Ladbury, Ray L.; Buchner, Stephen P.; Xapsos, Michael; Reed, Robert A.; Sanders, Anthony B.

    2003-01-01

    We present data on the vulnerability of a variety of candidate spacecraft electronics to proton and heavy ion induced single event effects. Devices tested include digital, analog, linear bipolar, and hybrid devices, among others.

  19. 11 CFR 100.148 - Volunteer activity for candidate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... stickers, handbills, brochures, posters, and yard signs) is not an expenditure on behalf of such...

  20. 11 CFR 100.148 - Volunteer activity for candidate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... developed by the candidate. But see 11 CFR 100.24, 104.17(a), and part 300, subparts D and E for exempt... stickers, handbills, brochures, posters, and yard signs) is not an expenditure on behalf of such...

  1. Astronaut Richard Truly and Candidate Frederick Hauck in shuttle simulator

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Astronaut Richard Truly and Astronaut Candidate Frederick Hauck in the Shuttle Mission Simulator in bldg 5 (Mission Simulation and Training Facility).They are in the flight deck seated at the commander and pilots seats checking documentation before simulation begins.

  2. Transforming objectivity to promote equity in transplant candidate selection.

    PubMed

    Majeske, R A

    1996-03-01

    It is necessary to recognize the variety of levels at which values and norms may inappropriately affect the equity of the transplantation process, including candidate selection. Using a revised, richer concept of objectivity, adopted from Longino's work in the philosophy of science and empirical studies of candidate selection, this paper examines what sort of objectivity can be obtained in the transplant candidate selection process, and the closely related question of how selection can occur in an equitable manner. This concept of objectivity requires that transformative criticism occur so that (1) the conceptual and normative commitments underlying selection may be articulated and perhaps challenged, and (2) the relationship between those commitments and criteria for candidate selection may be examined and justified, or revised. Through such transformative criticism, a greater degree of objectivity may be attained, which in turn will increase the likelihood of equity. PMID:8992646

  3. Value-Added Measures of Teacher Candidates' Dispositions

    ERIC Educational Resources Information Center

    Cosgrove, Maryellen; Carpenter, Barbara

    2012-01-01

    This article describes how a teacher preparation program can positively impact professional dispositions. Pre and post essays from a sample of sixty candidates were qualitatively analyzed to determine the value-added growth of their professional dispositions.

  4. Questions and Answers for Transplant Candidates about Kidney Allocation Policy

    MedlinePlus

    ... factors include: • Age • Length of time spent on dialysis • Having received a previous transplant (of any organ) • ... candidates who are less able to stay on dialysis for a long time. The 15 percent of ...

  5. Synthesis of Am80 (tamibarotene) prodrug candidates, congeners and metabolites.

    PubMed

    Muratake, Hideaki; Amano, Yohei; Toda, Takahiro; Sugiyama, Kiyoshi; Shudo, Koichi

    2013-01-01

    Compound 1 (IT-M-07000) was previously reported as a candidate prodrug of Am80 (Tamibarotene; used to treat acute promyelocytic leukemia), and shown to be efficiently metabolized to Am80 via β-oxidation. Here, we describe in detail the synthesis of 1, together with another tetradeuterated candidate prodrug, IT-YA-00616 (2), as well as two congeners, and several metabolic intermediates of 1 previously detected in mouse plasma. PMID:23902867

  6. Political partisanship influences perception of biracial candidates' skin tone.

    PubMed

    Caruso, Eugene M; Mead, Nicole L; Balcetis, Emily

    2009-12-01

    People tend to view members of their own political group more positively than members of a competing political group. In this article, we demonstrate that political partisanship influences people's visual representations of a biracial political candidate's skin tone. In three studies, participants rated the representativeness of photographs of a hypothetical (Study 1) or real (Barack Obama; Studies 2 and 3) biracial political candidate. Unbeknownst to participants, some of the photographs had been altered to make the candidate's skin tone either lighter or darker than it was in the original photograph. Participants whose partisanship matched that of the candidate they were evaluating consistently rated the lightened photographs as more representative of the candidate than the darkened photographs, whereas participants whose partisanship did not match that of the candidate showed the opposite pattern. For evaluations of Barack Obama, the extent to which people rated lightened photographs as representative of him was positively correlated with their stated voting intentions and reported voting behavior in the 2008 Presidential election. This effect persisted when controlling for political ideology and racial attitudes. These results suggest that people's visual representations of others are related to their own preexisting beliefs and to the decisions they make in a consequential context. PMID:19934033

  7. Transiting exoplanet candidates from K2 Campaigns 5 and 6

    NASA Astrophysics Data System (ADS)

    Pope, Benjamin J. S.; Parviainen, Hannu; Aigrain, Suzanne

    2016-06-01

    We introduce a new transit search and vetting pipeline for observations from the K2 mission, and present the candidate transiting planets identified by this pipeline out of the targets in Campaigns 5 and 6. Our pipeline uses the Gaussian Process-based K2SC code to correct for the K2 pointing systematics and simultaneously model stellar variability. The systematics-corrected, variability-detrended light curves are searched for transits with the Box Least Squares method, and a period-dependent detection threshold is used to generate a preliminary candidate list. Two or three individuals vet each candidate manually to produce the final candidate list, using a set of automatically-generated transit fits and assorted diagnostic tests to inform the vetting. We detect 147 single-planet system candidates and 5 multi-planet systems, independently recovering the previously-published hot Jupiters EPIC 212110888b, WASP-55b (EPIC 212300977b) and Qatar-2b (EPIC 212756297b). We also report the outcome of reconnaissance spectroscopy carried out for all candidates with Kepler magnitude Kp ≤ 13, identifying 12 targets as likely false positives. We compare our results to those of other K2 transit search pipelines, noting that ours performs particularly well for variable and/or active stars, but that the results are very similar overall. All the light curves and code used in the transit search and vetting process are publicly available, as are the follow-up spectra.

  8. Young Stellar Object Candidates in the Aquila Rift Region

    NASA Astrophysics Data System (ADS)

    Zhang, Miao-miao; Wang, Hong-chi; Stecklum, B.

    2010-10-01

    Using the 2m telescope of the Turingia State Observatory at Tauten-berg (TLS), imaging observations in 3 wavebands (H α, R and I) are performed in the 16 fields in the Aquila Rift region. The observed fields cover about 7 square degrees. Excluding the 3 fields with unqualified data, the photometrical analysis is made for the remaining 13 fields, from which point sources are identified, and finally 7 H α emission-line star candidates are identified by color-color diagrams. The 7 candidates are located in five fields. Three of them are located near the Galactic plane, while the galactic latitudes of the rest are greater than 4°. The 2 M ASS counterparts of the point sources are identified, and the properties of the 7 H α emission-line star candidates are further analyzed by using the two-color diagrams. It is found that the near-infrared radiation from these H α emission-line star candidates has no obvious infrared excess, one of them even falls on the main-sequence branch. This indicates that the H α-emissive young stellar objects (YSOs) are not always accompanied with the infrared excess, and that the results of the H α emission line observation and the infrared excess observation are mutually supplemented. If the 7 H α emission-line star candidates are regarded as YSO candidates, then the number of YSOs in the Aquila Rift region is quite small. The further confirmation of these candidates needs subsequent spectral observations.

  9. Integrative Data Mining Highlights Candidate Genes for Monogenic Myopathies

    PubMed Central

    Neto, Osorio Abath; Tassy, Olivier; Biancalana, Valérie; Zanoteli, Edmar; Pourquié, Olivier; Laporte, Jocelyn

    2014-01-01

    Inherited myopathies are a heterogeneous group of disabling disorders with still barely understood pathological mechanisms. Around 40% of afflicted patients remain without a molecular diagnosis after exclusion of known genes. The advent of high-throughput sequencing has opened avenues to the discovery of new implicated genes, but a working list of prioritized candidate genes is necessary to deal with the complexity of analyzing large-scale sequencing data. Here we used an integrative data mining strategy to analyze the genetic network linked to myopathies, derive specific signatures for inherited myopathy and related disorders, and identify and rank candidate genes for these groups. Training sets of genes were selected after literature review and used in Manteia, a public web-based data mining system, to extract disease group signatures in the form of enriched descriptor terms, which include functional annotation, human and mouse phenotypes, as well as biological pathways and protein interactions. These specific signatures were then used as an input to mine and rank candidate genes, followed by filtration against skeletal muscle expression and association with known diseases. Signatures and identified candidate genes highlight both potential common pathological mechanisms and allelic disease groups. Recent discoveries of gene associations to diseases, like B3GALNT2, GMPPB and B3GNT1 to congenital muscular dystrophies, were prioritized in the ranked lists, suggesting a posteriori validation of our approach and predictions. We show an example of how the ranked lists can be used to help analyze high-throughput sequencing data to identify candidate genes, and highlight the best candidate genes matching genomic regions linked to myopathies without known causative genes. This strategy can be automatized to generate fresh candidate gene lists, which help cope with database annotation updates as new knowledge is incorporated. PMID:25353622

  10. The CoRoT transit candidate catalog

    NASA Astrophysics Data System (ADS)

    Aigrain, S.; Deleuil, M.

    2013-09-01

    We present a full catalog of all the candidate transiting planets identified by the CoRoT space mission during its first 5 years of operations, including homogeneously derived transit parameters, validation diagnostics and a summary of the outcome of follow-up observations, where available.The catalog includes confirmed planets, clear false alarms (mainly blended or grazing eclipsing binaries), but also dozens of unconfirmed cases, where the follow-up was either inconclusive (hot stars, fast rotators) or incomplete (owing to limited telescope time and the relatively faint nature of the CoRoT targets). The catalog is intended primarily as a resource for the community, for example as a starting point for completeness and population studies. The candidate detection and selection processes have evolved significantly over the course of the mission. Several teams independently analyse the light curves from each observing run, searching for transits and providing ranked candidate lists, which are subsequently merged and ranked manually. This enables the use of some specialist methods, which are better suited to the detection of only certain types of transits, but makes it difficult to provide an overall assessment of the sensitivity of the mission to transits of different depths and periods. However, we note the transit search methods used by the different teams have gradually converged since launch, and there are now fewer teams actively involved in the transit search, with more overlap between the resulting candidate lists. For each CoRoT observing run, one team member coordinates the selection of candidates for followup, with input from the other team members. The set of criteria used to perform this selection have also evolved over the years, becoming more homogeneous. In particular, the light curve fitting tools used to produce the transit parameters and other diagnostics, which are included in the present catalog, are now routinely used to validate candidates and

  11. ALMOST ALL OF KEPLER'S MULTIPLE-PLANET CANDIDATES ARE PLANETS

    SciTech Connect

    Lissauer, Jack J.; Rowe, Jason F.; Bryson, Stephen T.; Howell, Steve B.; Jenkins, Jon M.; Kinemuchi, Karen; Koch, David G.; Marcy, Geoffrey W.; Adams, Elisabeth; Fressin, Francois; Geary, John; Holman, Matthew J.; Ragozzine, Darin; Buchhave, Lars A.; Ciardi, David R.; Fabrycky, Daniel C.; Ford, Eric B.; Morehead, Robert C.; Gilliland, Ronald L.; and others

    2012-05-10

    We present a statistical analysis that demonstrates that the overwhelming majority of Kepler candidate multiple transiting systems (multis) indeed represent true, physically associated transiting planets. Binary stars provide the primary source of false positives among Kepler planet candidates, implying that false positives should be nearly randomly distributed among Kepler targets. In contrast, true transiting planets would appear clustered around a smaller number of Kepler targets if detectable planets tend to come in systems and/or if the orbital planes of planets encircling the same star are correlated. There are more than one hundred times as many Kepler planet candidates in multi-candidate systems as would be predicted from a random distribution of candidates, implying that the vast majority are true planets. Most of these multis are multiple-planet systems orbiting the Kepler target star, but there are likely cases where (1) the planetary system orbits a fainter star, and the planets are thus significantly larger than has been estimated, or (2) the planets orbit different stars within a binary/multiple star system. We use the low overall false-positive rate among Kepler multis, together with analysis of Kepler spacecraft and ground-based data, to validate the closely packed Kepler-33 planetary system, which orbits a star that has evolved somewhat off of the main sequence. Kepler-33 hosts five transiting planets, with periods ranging from 5.67 to 41 days.

  12. Unifying Candidate Gene and GWAS Approaches in Asthma

    PubMed Central

    Michel, Sven; Liang, Liming; Depner, Martin; Klopp, Norman; Ruether, Andreas; Kumar, Ashish; Schedel, Michaela; Vogelberg, Christian; von Mutius, Erika; von Berg, Andrea; Bufe, Albrecht; Rietschel, Ernst; Heinzmann, Andrea; Laub, Otto; Simma, Burkhard; Frischer, Thomas; Genuneit, Jon; Gut, Ivo G.; Schreiber, Stefan; Lathrop, Mark; Illig, Thomas; Kabesch, Michael

    2010-01-01

    The first genome wide association study (GWAS) for childhood asthma identified a novel major susceptibility locus on chromosome 17q21 harboring the ORMDL3 gene, but the role of previous asthma candidate genes was not specifically analyzed in this GWAS. We systematically identified 89 SNPs in 14 candidate genes previously associated with asthma in >3 independent study populations. We re-genotyped 39 SNPs in these genes not covered by GWAS performed in 703 asthmatics and 658 reference children. Genotyping data were compared to imputation data derived from Illumina HumanHap300 chip genotyping. Results were combined to analyze 566 SNPs covering all 14 candidate gene loci. Genotyped polymorphisms in ADAM33, GSTP1 and VDR showed effects with p-values <0.0035 (corrected for multiple testing). Combining genotyping and imputation, polymorphisms in DPP10, EDN1, IL12B, IL13, IL4, IL4R and TNF showed associations at a significance level between p = 0.05 and p = 0.0035. These data indicate that (a) GWAS coverage is insufficient for many asthma candidate genes, (b) imputation based on these data is reliable but incomplete, and (c) SNPs in three previously identified asthma candidate genes replicate in our GWAS population with significance after correction for multiple testing in 14 genes. PMID:21103062

  13. Statistical Eclipses of Kepler Neptune-like Candidates

    NASA Astrophysics Data System (ADS)

    Sheets, Holly A.; Deming, Drake

    2015-01-01

    We present the results of our work to detect secondary eclipses of Neptune-like planets in Kepler's long cadence data and to determine their average albedo. Our method is inherently statistical in nature: we scale and combine photometric data for groups of planets to infer their average eclipse depths, and to greatly increase the signal-to-noise. We have modified our method for averaging short cadence light curves of multiple planet candidates (ApJ, in press), and have applied it to long cadence data. We transform the phase of the individual candidates to match a reference candidate, such that the light curves add constructively, and we account for the broadening of the eclipse due to the 30 minute cadence. In the short cadence data, we found that a group of close-in sub-Saturn candidates (1 to 6 Earth radii) was more reflective than typical hot Jupiters. With the larger number of candidates available in long cadence, we expect to improve the resolution in radius, focusing on Neptune-like planets.

  14. [Strategy of molecular drug design: hits, leads and drug candidates].

    PubMed

    Guo, Zong-ru

    2008-09-01

    Hits, leads and drug candidates constitute three millstones in the course of drug discovery and development. The definition of drug candidates is a critical point in the value chain of drug innovation, which not only differentiates the research and development stages, but more importantly, determines the perspective and destiny of the pre-clinical and clinical studies. All outcomes from the development stage are actually attributed to the chemical structure of candidates. The quality of candidates, however, is restricted by the drug-likeness of lead compounds, which in turn is decided by the characteristics of hits. The hit-to-lead is to provide a promising and druggable structure for further development, whereas the optimization of lead compounds is a process to transform an active compound into a drug, which in essence is molecular manipulation in multi-dimensional space related to pharmacodynamic, pharmacokinetic, physico-chemical, and safety properties. This review discusses the strategic principles in hit discovery, lead identification and optimization, as well as drug candidate definition with practical examples. PMID:19048779

  15. Emotional and Affective Temperaments in Smoking Candidates for Bariatric Surgery

    PubMed Central

    Mombach, Karin Daniele; de Souza Brito, Cesar Luis; Padoin, Alexandre Vontobel; Casagrande, Daniela Schaan; Mottin, Claudio Cora

    2016-01-01

    Introduction The prevalence of smoking habits in severe obesity is higher than in the general population. There is some evidence that smokers have different temperaments compared to non-smokers. The aim of this study is to evaluate the associations between smoking status (smokers, ex-smokers and non-smokers) and temperament characteristics in bariatric surgery candidates. Methods We analyzed data on temperament of 420 bariatric surgery candidates, as assessed by the AFECTS scale, in an exploratory cross-sectional survey of bariatric surgery candidates who have been grouped into smokers, ex-smokers and non-smokers. Results We detected significant statistical differences in temperament related to the smoking status in this population after controlling the current use of psychiatric medication. Smokers had higher anxiety and lower control than non-smokers. Ex-smokers with BMI >50 kg/m2 presented higher coping and control characteristics than smokers. Conclusions Smoking in bariatric surgery candidates was associated with lower control and higher anxious temperament, when controlled by current use of psychiatric medication. Smokers with BMI >50 kg/m2 presented lower coping and control than ex-smokers. Assessment of temperament in bariatric surgery candidates may help in decisions about smoking cessation treatment and prevention of smoking relapse after surgery. PMID:26987115

  16. Integrative analysis to select cancer candidate biomarkers to targeted validation.

    PubMed

    Kawahara, Rebeca; Meirelles, Gabriela V; Heberle, Henry; Domingues, Romênia R; Granato, Daniela C; Yokoo, Sami; Canevarolo, Rafael R; Winck, Flavia V; Ribeiro, Ana Carolina P; Brandão, Thaís Bianca; Filgueiras, Paulo R; Cruz, Karen S P; Barbuto, José Alexandre; Poppi, Ronei J; Minghim, Rosane; Telles, Guilherme P; Fonseca, Felipe Paiva; Fox, Jay W; Santos-Silva, Alan R; Coletta, Ricardo D; Sherman, Nicholas E; Paes Leme, Adriana F

    2015-12-22

    Targeted proteomics has flourished as the method of choice for prospecting for and validating potential candidate biomarkers in many diseases. However, challenges still remain due to the lack of standardized routines that can prioritize a limited number of proteins to be further validated in human samples. To help researchers identify candidate biomarkers that best characterize their samples under study, a well-designed integrative analysis pipeline, comprising MS-based discovery, feature selection methods, clustering techniques, bioinformatic analyses and targeted approaches was performed using discovery-based proteomic data from the secretomes of three classes of human cell lines (carcinoma, melanoma and non-cancerous). Three feature selection algorithms, namely, Beta-binomial, Nearest Shrunken Centroids (NSC), and Support Vector Machine-Recursive Features Elimination (SVM-RFE), indicated a panel of 137 candidate biomarkers for carcinoma and 271 for melanoma, which were differentially abundant between the tumor classes. We further tested the strength of the pipeline in selecting candidate biomarkers by immunoblotting, human tissue microarrays, label-free targeted MS and functional experiments. In conclusion, the proposed integrative analysis was able to pre-qualify and prioritize candidate biomarkers from discovery-based proteomics to targeted MS. PMID:26540631

  17. Network analysis of EtOH-related candidate genes.

    PubMed

    Guo, An-Yuan; Sun, Jingchun; Jia, Peilin; Zhao, Zhongming

    2010-05-01

    Recently, we collected many large-scale datasets for alcohol dependence and EtOH response in five organisms and deposited them in our EtOH-related gene resource database (ERGR, http://bioinfo.mc.vanderbilt.edu/ERGR/). Based on multidimensional evidence among these datasets, we prioritized 57 EtOH-related candidate genes. To explore their biological roles, and the molecular mechanisms of EtOH response and alcohol dependence, we examined the features of these genes by the Gene Ontology (GO) term-enrichment test and network/pathway analysis. Our analysis revealed that these candidate genes were highly enriched in alcohol dependence/alcoholism and highly expressed in brain or liver tissues. All the significantly enriched GO terms were related to neurotransmitter systems or EtOH metabolic processes. Using the Ingenuity Pathway Analysis system, we found that these genes were involved in networks of neurological disease, cardiovascular disease, inflammatory response, and small molecular metabolism. Many key genes in signaling pathways were in the central position of these networks. Furthermore, our protein-protein interaction (PPI) network analysis suggested some novel candidate genes which also had evidence in the ERGR database. This study demonstrated that our candidate gene selection is effective and our network/pathway analysis is useful for uncovering the molecular mechanisms of EtOH response and alcohol dependence. This approach can be applied to study the features of candidate genes of other complex traits/phenotypes. PMID:20491071

  18. Integrative analysis to select cancer candidate biomarkers to targeted validation

    PubMed Central

    Heberle, Henry; Domingues, Romênia R.; Granato, Daniela C.; Yokoo, Sami; Canevarolo, Rafael R.; Winck, Flavia V.; Ribeiro, Ana Carolina P.; Brandão, Thaís Bianca; Filgueiras, Paulo R.; Cruz, Karen S. P.; Barbuto, José Alexandre; Poppi, Ronei J.; Minghim, Rosane; Telles, Guilherme P.; Fonseca, Felipe Paiva; Fox, Jay W.; Santos-Silva, Alan R.; Coletta, Ricardo D.; Sherman, Nicholas E.; Paes Leme, Adriana F.

    2015-01-01

    Targeted proteomics has flourished as the method of choice for prospecting for and validating potential candidate biomarkers in many diseases. However, challenges still remain due to the lack of standardized routines that can prioritize a limited number of proteins to be further validated in human samples. To help researchers identify candidate biomarkers that best characterize their samples under study, a well-designed integrative analysis pipeline, comprising MS-based discovery, feature selection methods, clustering techniques, bioinformatic analyses and targeted approaches was performed using discovery-based proteomic data from the secretomes of three classes of human cell lines (carcinoma, melanoma and non-cancerous). Three feature selection algorithms, namely, Beta-binomial, Nearest Shrunken Centroids (NSC), and Support Vector Machine-Recursive Features Elimination (SVM-RFE), indicated a panel of 137 candidate biomarkers for carcinoma and 271 for melanoma, which were differentially abundant between the tumor classes. We further tested the strength of the pipeline in selecting candidate biomarkers by immunoblotting, human tissue microarrays, label-free targeted MS and functional experiments. In conclusion, the proposed integrative analysis was able to pre-qualify and prioritize candidate biomarkers from discovery-based proteomics to targeted MS. PMID:26540631

  19. LR1: a candidate RNA virus of Leishmania.

    PubMed Central

    Tarr, P I; Aline, R F; Smiley, B L; Scholler, J; Keithly, J; Stuart, K

    1988-01-01

    Although viruses are important biological agents and useful molecular tools, little is known about the viruses of parasites. We report here the discovery of a candidate for an RNA virus in a kinetoplastid parasite. This potential virus, which we term LR1, is present in the promastigote form of the human pathogen Leishmania braziliensis guyanensis CUMC1-1A but not in 11 other stocks of Leishmania that were examined nor in Trypanosoma brucei. The candidate viral RNA has a size of approximately 6000 nucleotides, is single-stranded, and is largely, if not exclusively, located in the cytoplasm. No homologous LR1 sequences are detected in genomic DNA. The candidate viral RNA is associated with a spherical particle 32 nm in diameter that has a sedimentation coefficient of approximately 130 S. There is as yet no evident effect of this potential virus on parasite physiology or the disease caused by the parasite. Images PMID:3200841

  20. Preoperative cardiovascular investigations in liver transplant candidate: An update

    PubMed Central

    Sehgal, Lalit; Srivastava, Piyush; Pandey, Chandra Kant; Jha, Amit

    2016-01-01

    Cardiovascular complications are a major cause of morbidity and mortality in patients with end-stage liver disease (ESLD) undergoing liver transplantation. Identifying candidates at the highest risk of postoperative cardiovascular complications is the cornerstone for optimizing the outcome. Ischaemic heart disease contributes to major portion of cardiovascular complications and therefore warrants evaluation in the preoperative period. Patients of ESLD usually demonstrate increased cardiac output, compromised ventricular response to stress, low systemic vascular resistance and occasionally bradycardia. Despite various recommendations for preoperative evaluation of cardiovascular disease in liver transplant candidates, a considerable controversy on screening methodology persists. This review critically focuses on the rapidly expanding body of evidence for diagnosis and risk stratification of cardiovascular disorder in liver transplant candidates. PMID:26962249

  1. A genomic view on epilepsy and autism candidate genes.

    PubMed

    Jabbari, Kamel; Nürnberg, Peter

    2016-07-01

    Epilepsy is a common complex disorder most frequently associated with psychiatric and neurological diseases. Massive parallel sequencing of individual or cohort genomes and exomes led the identification of several disease associated genes. We review here the candidate genes in epilepsy genetics with focus on exome and gene panel data. Together with the examination of brain expressed genes and post synaptic proteome the results show that: (1) Non-metabolic epilepsies and autism candidate genes tend to be AT-rich and (2) large transcript size and local AT-richness are characteristic features of genes involved in developmental brain disorders and synaptic functions. These results point to the preferential location of core epilepsy and autism candidate genes in late replicating, GC-poor chromosomal regions (isochores). These results indicate that the genomic alterations leading to some brain disorders are confined to responsive chromatin areas harboring brain critical genes. PMID:26772991

  2. New Candidates for Supernova Remnants in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Kavanagh, Patrick

    2013-10-01

    We propose observations of five new candidates for X-ray supernova remnants (SNRs) in the Large Magellanic Cloud (LMC), which were detected in ROSAT data and classified as SNR candidates based on their X-ray, radio, and optical properties. Five sources have already been observed (AO9 and AO12, Prop. IDs 65188 and 72044; AO11, VLP-LMC survey) and confirm the reliability of our candidate selection. The high sensitivity of XMM-Newton will allow us to detect SNRs that are X-ray faint due to their age or ambient medium, and complete the sample of known SNRs to lower fluxes. We will thus be able to perform statistical studies by, e.g., constructing a more complete X-ray luminosity function of SNRs in the LMC and will obtain information about typical abundances, densities, and initial supernova energies.

  3. A new tribological test for candidate brush seal materials evaluation

    SciTech Connect

    Fellenstein, J.A.; DellaCorte, C.

    1994-10-01

    A new tribological test for candidate brush seal materials evaluation has been developed. The sliding contact between the brush seal wires and their mating counterface journal is simulated by testing a small tuft of wire against the outside diameter of a high speed rotating shaft. The test configuration is similar to a standard block on ring geometry. The new tester provides the capability to measure both the friction and wear of candidate wire and counterface materials under controlled loading conditions in the gram to kilogram range. A wide test condition latitude of speeds (1 to 27 m/s), temperatures (25 to 700C), and loads (0.5 to 10 N) enables the simulation of many of the important tribological parameters found in turbine engine brush seals. This paper describes the new test rig and specimen configuration and presents initial data for candidate seal materials comparing tuft test results and wear surface morphology to field tested seal components.

  4. Evaluation and selection of candidate high-level waste forms

    SciTech Connect

    Bernadzikowski, T. A.; Allender, J. S.; Butler, J. L.; Gordon, D. E.; Gould, Jr., T. H.; Stone, J. A.

    1982-03-01

    Seven candidate waste forms being developed under the direction of the Department of Energy's National High-Level Waste (HLW) Technology Program, were evaluated as potential media for the immobilization and geologic disposal of high-level nuclear wastes. The evaluation combined preliminary waste form evaluations conducted at DOE defense waste-sites and independent laboratories, peer review assessments, a product performance evaluation, and a processability analysis. Based on the combined results of these four inputs, two of the seven forms, borosilicate glass and a titanate based ceramic, SYNROC, were selected as the reference and alternative forms for continued development and evaluation in the National HLW Program. Both the glass and ceramic forms are viable candidates for use at each of the DOE defense waste-sites; they are also potential candidates for immobilization of commercial reprocessing wastes. This report describes the waste form screening process, and discusses each of the four major inputs considered in the selection of the two forms.

  5. Candidate genes that affect aging through protein homeostasis.

    PubMed

    Argon, Yair; Gidalevitz, Tali

    2015-01-01

    Because aging is a multifactorial, pleiotropic process where many interacting mechanisms contribute to the organismal decline, the candidate gene approach rarely provides a clear message. This chapter discusses some of the inherent complexity, focusing on aspects that impinge upon protein homeostasis and maintain a healthy proteome. We discuss candidate genes that operate in these pathways, and compare their actions in invertebrates, mice and humans. We highlight several themes that emerge from recent research—the interconnections of pathways that regulate aging, the pleiotropic effects of mutations and other manipulations of the candidate proteins and the tissue specificity in these pleiotropic outcomes. This body of knowledge highlights the need for multiple specific readouts of manipulating longevity genes, beyond measuring lifespan, as well as the need to understand the integrated picture, beyond examining the immediate outputs of individual longevity pathways. PMID:25916585

  6. A New Tribological Test for Candidate Brush Seal Materials Evaluation

    NASA Technical Reports Server (NTRS)

    Fellenstein, James A.; Dellacorte, Christopher

    1994-01-01

    A new tribological test for candidate brush seal materials evaluation has been developed. The sliding contact between the brush seal wires and their mating counterface journal is simulated by testing a small tuft of wire against the outside diameter of a high speed rotating shaft. The test configuration is similar to a standard block on ring geometry. The new tester provides the capability to measure both the friction and wear of candidate wire and counterface materials under controlled loading conditions in the gram to kilogram range. A wide test condition latitude of speeds (1 to 27 m/s), temperatures (25 to 700 C), and loads (0.5 to 10 N) enables the simulation of many of the important tribological parameters found in turbine engine brush seals. This paper describes the new test rig and specimen configuration and presents initial data for candidate seal materials comparing tuft test results and wear surface morphology to field tested seal components.

  7. Counts of low-Redshift SDSS quasar candidates

    SciTech Connect

    Zeljko Ivezic et al.

    2004-03-12

    We analyze the counts of low-redshift quasar candidates selected using nine-epoch SDSS imaging data. The co-added catalogs are more than 1 mag deeper than single-epoch SDSS data, and allow the selection of low-redshift quasar candidates using UV-excess and also variability techniques. The counts of selected candidates are robustly determined down to g = 21.5. This is about 2 magnitudes deeper than the position of a change in the slope of the counts reported by Boyle et al. (1990, 2000) for a sample selected by UV-excess, and questioned by Hawkins & Veron (1995), who utilized a variability-selected sample. Using SDSS data, we confirm a change in the slope of the counts for both UV-excess and variability selected samples, providing strong support for the Boyle et al. results.

  8. PEACE: pulsar evaluation algorithm for candidate extraction - a software package for post-analysis processing of pulsar survey candidates

    NASA Astrophysics Data System (ADS)

    Lee, K. J.; Stovall, K.; Jenet, F. A.; Martinez, J.; Dartez, L. P.; Mata, A.; Lunsford, G.; Cohen, S.; Biwer, C. M.; Rohr, M.; Flanigan, J.; Walker, A.; Banaszak, S.; Allen, B.; Barr, E. D.; Bhat, N. D. R.; Bogdanov, S.; Brazier, A.; Camilo, F.; Champion, D. J.; Chatterjee, S.; Cordes, J.; Crawford, F.; Deneva, J.; Desvignes, G.; Ferdman, R. D.; Freire, P.; Hessels, J. W. T.; Karuppusamy, R.; Kaspi, V. M.; Knispel, B.; Kramer, M.; Lazarus, P.; Lynch, R.; Lyne, A.; McLaughlin, M.; Ransom, S.; Scholz, P.; Siemens, X.; Spitler, L.; Stairs, I.; Tan, M.; van Leeuwen, J.; Zhu, W. W.

    2013-07-01

    Modern radio pulsar surveys produce a large volume of prospective candidates, the majority of which are polluted by human-created radio frequency interference or other forms of noise. Typically, large numbers of candidates need to be visually inspected in order to determine if they are real pulsars. This process can be labour intensive. In this paper, we introduce an algorithm called Pulsar Evaluation Algorithm for Candidate Extraction (PEACE) which improves the efficiency of identifying pulsar signals. The algorithm ranks the candidates based on a score function. Unlike popular machine-learning-based algorithms, no prior training data sets are required. This algorithm has been applied to data from several large-scale radio pulsar surveys. Using the human-based ranking results generated by students in the Arecibo Remote Command Center programme, the statistical performance of PEACE was evaluated. It was found that PEACE ranked 68 per cent of the student-identified pulsars within the top 0.17 per cent of sorted candidates, 95 per cent within the top 0.34 per cent and 100 per cent within the top 3.7 per cent. This clearly demonstrates that PEACE significantly increases the pulsar identification rate by a factor of about 50 to 1000. To date, PEACE has been directly responsible for the discovery of 47 new pulsars, 5 of which are millisecond pulsars that may be useful for pulsar timing based gravitational-wave detection projects.

  9. Bioinformatic analysis of expression data to identify effector candidates.

    PubMed

    Reid, Adam J; Jones, John T

    2014-01-01

    Pathogens produce effectors that manipulate the host to the benefit of the pathogen. These effectors are often secreted proteins that are upregulated during the early phases of infection. These properties can be used to identify candidate effectors from genomes and transcriptomes of pathogens. Here we describe commonly used bioinformatic approaches that (1) allow identification of genes encoding predicted secreted proteins within a genome and (2) allow the identification of genes encoding predicted secreted proteins that are upregulated at important stages of the life cycle. Other approaches for bioinformatic identification of effector candidates, including OrthoMCL analysis to identify expanded gene families, are also described. PMID:24643549

  10. Dark matter candidates and methods for detecting them

    NASA Technical Reports Server (NTRS)

    Raffelt, G. G.

    1992-01-01

    A number of experiments employing Ge and Si ionization detectors have excluded large regions in the plane of masses and scattering cross-sections for weakly-interacting dark matter (DM) candidates. It is judged that, before a realistic detection experiment for supersymmetric DM candidates can be conducted, significant development efforts will have to be completed for suitable cryogenic or ionization detectors. Pilot experiments have demonstrated the feasibility of axion searches with microwave cavities, but these are at least two orders of magnitude too low in sensitivity.

  11. Ethical issues in the psychosocial assessment of bariatric surgery candidates.

    PubMed

    Rouleau, Codie R; Rash, Joshua A; Mothersill, Kerry J

    2016-07-01

    Psychosocial evaluation is recommended prior to bariatric surgery. Practice guidelines have been published on assessment methods for bariatric surgery candidates, but they have not emphasized ethical issues with this population. This review outlines ethical and professional considerations for behavioral healthcare providers who conduct pre-surgical assessments of bariatric surgery candidates by merging ethical principles for mental health professionals with current practices in pre-surgical assessments. Issues discussed include the following: (a) establishing and maintaining competence, (b) obtaining informed consent, (c) respecting confidentiality, (d) avoiding bias and discrimination, (e) avoiding and addressing dual roles, (f) selecting and using psychological tests, and (g) acknowledging limitations of psychosocial assessments. PMID:25411197

  12. Dark matter candidates: a ten-point test

    SciTech Connect

    Taoso, Marco; Masiero, Antonio; Bertone, Gianfranco E-mail: bertone@iap.fr

    2008-03-15

    An extraordinarily rich zoo of non-baryonic dark matter candidates has been proposed over the last three decades. Here we present a ten-point test that a new particle has to pass in order to be considered a viable DM candidate. (I) Does it match the appropriate relic density? (II) Is it cold? (III) Is it neutral? (IV) Is it consistent with BBN? (V) Does it leave stellar evolution unchanged? (VI) Is it compatible with constraints on self-interactions? (VII) Is it consistent with direct DM searches? (VIII) Is it compatible with gamma-ray constraints? (IX) Is it compatible with other astrophysical bounds? (X) Can it be probed experimentally?.

  13. Kepler Mission Discovers Trove of Extrasolar Planet Candidates

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-02-01

    NASA's Kepler discovery mission is collecting more than just pennies from heaven. Results from the first 4 months of science operations of the Kepler space telescope, announced on 2 February, include the discovery of 1235 candidate planets orbiting 997 stars in a small portion of the Milky Way galaxy examined by the telescope. Follow-up observations likely could confirm about 80% of the candidates as actual planets rather than false positives, according to researchers. This new trove of possible exoplanets could greatly expand the number of known planets outside of our solar system.

  14. Spectroscopic Observations of the Recent M33 Nova Candidate

    NASA Astrophysics Data System (ADS)

    Shafter, A. W.; Ciardullo, R.; Bode, M. F.; Darnley, M. J.; Misselt, K. A.

    2010-10-01

    We report spectroscopic observations of the recent M33 nova candidate (M33N 2010-10a?), which was discovered by K. Nishiyama and F. Kabashima (Miyaki-Argenteus Observatory, Japan) on 2010 Oct. 26.65 UT. At our request a spectrum (410-950 nm) of the nova candidate was obtained by John Caldwell on 2010 Oct. 28.37 UT (~2 days post discovery) with the Marcario Low-Resolution Spectrograph on the 9.2m Hobby-Eberly Telescope.

  15. A Systematic Search for Exoplanet Candidates in K2 Data

    NASA Astrophysics Data System (ADS)

    Kahre, Tarryn; Karnes, Katherine L.; Caldwell, Douglas A.; Smith, Jeffrey C.

    2016-01-01

    We present a catalog of 41 promising exoplanet candidates in 33 stellar systems from the K2 Campaign 3 data. The K2 Mission was developed upon the mechanical failure of the second of four reaction wheels, as the Kepler Spacecraft could not continue the original Kepler Mission. The Kepler Mission was a 4-year mission designed to determine the prevalence of exoplanets in our galaxy, and the configuration and diversity of those planetary systems discovered. The K2 Mission has a similar goal, though the spacecraft now points at fields along the ecliptic in ~75 day campaigns (Howell et al. 2014). Although the light curves in K2 data are noisier and have significant motion-induced systematics, it has been shown that there is success in finding exoplanets and exoplanet candidates (Foreman-Mackey et al. 2015; Montet et al. 2015). Utilizing the Transiting Planet Search and Data Validation from the Kepler Processing Pipeline, we systematically search K2 Campaign 3 for potential exoplanet candidates. Setting a 7.1s maximum folded statistic threshold minimum for a minimum of three transit events, we define our initial candidate list. Our list is further narrowed by the results from Data Validation, as it allows us to statistically identify false positives, such as eclipsing binaries or uncorrected roll-drift, in our sample. We further draw parallels between our results and other transit-searching pipeline results published for Campaign 3.

  16. Supervising PETE Candidates Using the Situational Supervision Model

    ERIC Educational Resources Information Center

    Levy, Linda S.; Johnson, Lynn V.

    2012-01-01

    Physical education teacher candidates (PETCs) often, as part of their curricular requirements, engage in early field experiences that prepare them for student teaching. Matching the PETC's developmental level with the mentor's supervision style enhances this experience. The situational supervision model, based on the situational leadership model,…

  17. Community Arts and Teacher Candidates: A Study in Civic Engagement

    ERIC Educational Resources Information Center

    Briggs, Judith; McHenry, Kimberly

    2013-01-01

    Within an afterschool community arts program for underserved children, teacher candidates tested prescribed teaching methods, experimented with teaching styles, and worked cooperatively with peers and faculty to enhance the children's creativity and sense of accomplishment. Students connected theoretical classroom knowledge to real-world…

  18. Candidates for Young Super Star Clusters in the Milky Way

    NASA Astrophysics Data System (ADS)

    Rahman, Mubdi; Matzner, C. D.; Moon, D.

    2011-01-01

    Massive Star Clusters (M > 104 M⊙) have been known to exist throughout the local Universe, but few such objects have been found within our own Galaxy. These clusters the majority of the galactic OB star formation, and thus dramatically alter their surroundings through winds, ionizing flux and radiation pressure, and supernovae, eventually destroying their natal clouds and inflating superbubbles which will erupt from the Galactic plane. We search for the young stellar clusters within the star forming complexes identified by Rahman & Murray (2010) using the WMAP free-free and Spitzer GLIMPSE 8 micron observations. Located far across the Galactic plane, these clusters are highly extinguished and crowded by field stars. Using the 2MASS catalogue, we have developed a method of identifying overdensities of sources with colours consistent with the extinguished upper main sequence coincident with the star forming complexes. The difficulty in this method comes from the large number of overlapping foreground sources in comparison to the expected number of cluster sources in any given candidate cluster. We identify a candidate for the most massive young cluster in the Galaxy (M 105 M⊙), which we have dubbed the Dragonfish Cluster. The candidate cluster is at a distance of 9.7 kpc and has a total ionizing luminosity of 7×1051 photons s-1. We identify nearly 400 OB star candidates associated with the cluster, to be confirmed with near-infrared spectroscopy.

  19. ANALYTICAL METHOD READINESS FOR THE CONTAMINANT CANDIDATE LIST

    EPA Science Inventory

    The Contaminant Candidate List (CCL), which was promulgated in March 1998, includes 50 chemical and 10 microbiological contaminants/contaminant groups. At the time of promulgation, analytical methods were available for 6 inorganic and 28 organic contaminants. Since then, 4 anal...

  20. Science review: Searching for gene candidates in acute lung injury

    PubMed Central

    Grigoryev, Dmitry N; Finigan, James H; Hassoun, Paul; Garcia, Joe GN

    2004-01-01

    Acute lung injury (ALI) is a complex and devastating illness, often occurring within the setting of sepsis, and carries an annual mortality rate of 30–50%. Although the genetic basis of ALI has not been fully established, an increasing body of evidence suggests that genetic predisposition contributes to disease susceptibility and severity. Significant difficulty exists, however, in defining the exact nature of these genetic factors, including large phenotypic variance, incomplete penetrance, complex gene–environment interactions, and strong potential for locus heterogeneity. We utilized the candidate gene approach and an ortholog gene database to provide relevant gene ontologies and insights into the genetic basis of ALI. We employed a Medline search of selected basic and clinical studies in the English literature and studies sponsored by the HopGene National Institutes of Health sponsored Program in Genomic Applications. Extensive gene expression profiling studies in animal models of ALI (rat, murine, canine), as well as in humans, were performed to identify potential candidate genes . We identified a number of candidate genes for ALI, with blood coagulation and inflammation gene ontologies being the most highly represented. The candidate gene approach coupled with extensive gene profiling and novel bioinformatics approaches is a valuable way to identify genes that are involved in ALI. PMID:15566614

  1. Organizing a Congressional Candidate Debate as Experiential Learning

    ERIC Educational Resources Information Center

    Boeckelman, Keith; Deitz, Janna L.; Hardy, Richard J.

    2008-01-01

    This article describes a political debate among congressional candidates that the authors organized in 2006. The debate was structured to maximize student involvement both in the planning stages and during the event itself. After discussing relevant literature on experiential learning, the article describes the debate format and details the issues…

  2. From Teacher Candidates to ESL Ambassadors in Teacher Education

    ERIC Educational Resources Information Center

    Schmidt, Clea

    2005-01-01

    This paper analyzes the process and impact of a pre-service teacher education course assignment that engaged teacher candidates in developing and delivering an ESL professional development night for faculty colleagues and teachers from the field. The night involved a reader's theatre performance and follow-up discussion of Tara Goldstein's (2003)…

  3. Journey of "Becoming": Secondary Teacher Candidates' Concerns and Struggles

    ERIC Educational Resources Information Center

    Cooper, Jewell E.; He, Ye

    2012-01-01

    As is widely recognized in the teacher education field, it is a complex process for teacher candidates to become effective classroom teachers. With growing linguistic and cultural diversity in today's classrooms, as well as different social expectations for education, the teacher preparation process is becoming increasingly demanding and…

  4. DISTRIBUTION SYSTEM EVALUATIONS OF THE CONTAMINANT CANDIDATE LIST

    EPA Science Inventory

    The Safe Drinking Water Act (SDWA), as amended in 1996, requires EPA to establish a list of unregulated microbiological and chemical contaminants to aid in priority setting for the Agency's drinking water program. The list is referred to as the Contaminant Candidate List (CCL). A...

  5. Effects of Critical Thinking Intervention for Early Childhood Teacher Candidates

    ERIC Educational Resources Information Center

    Han, Heejeong Sophia; Brown, E. Todd

    2013-01-01

    This study is based on an intervention designed to enhance early childhood teacher candidates' critical thinking abilities. The concept, elements, standards, and traits of critical thinking were integrated into the main course contents, and the effects of the intervention were examined. The results indicated that early childhood teacher…

  6. Developing the "Pedagogical Efficacy Perception Scale" for Teacher Candidates

    ERIC Educational Resources Information Center

    Akbaba, Ahmet

    2015-01-01

    This study aims to develop the "Pedagogical Efficacy Perception Scale" for teacher candidates and to compare scale scores. The sample of this survey model study consists of 310 students studying in a faculty of education. The "Pedagogical Efficacy Perception Scale" developed by the author was used for data collection.…

  7. Supernova candidates discovered with Subaru/Hyper Suprime-Cam

    NASA Astrophysics Data System (ADS)

    Tominaga, Nozomu; Morokuma, Tomoki; Tanaka, Masaomi; Yasuda, Naoki; Furusawa, Hisanori; Morii, Mikio; Ikeda, Shiro; Ueda, Naonori; Yamato, Junji; Ishiguro, Katsuhiko; Nakamura, Yoshitaka; Yamanaka, Akihiro; Yoshida, Naoki; Suzuki, Nao; Jiang, Ji-an; Kato, Takahiro; Taniguchi, Yuki; Shibata, Takumi; Miyazaki, Satoshi; Moriya, Takashi J.; Noumaru, Junichi; Schubert, Kiaina; Takata, Tadafumi

    2015-08-01

    We report the discovery of 10 supernova candidates from a transient survey with Subaru/Hyper Suprime-Cam (HSC). Our Subaru/HSC open-use observations were performed on 19 Aug 2015 UT, under poor weather condition with 1.1-1.5 arcsec seeing.

  8. Candidate Chemosensory Genes in the Stemborer Sesamia nonagrioides

    PubMed Central

    Glaser, Nicolas; Gallot, Aurore; Legeai, Fabrice; Montagné, Nicolas; Poivet, Erwan; Harry, Myriam; Calatayud, Paul-André; Jacquin-Joly, Emmanuelle

    2013-01-01

    The stemborer Sesamia nonagrioides is an important pest of maize in the Mediterranean Basin. Like other moths, this noctuid uses its chemosensory system to efficiently interact with its environment. However, very little is known on the molecular mechanisms that underlie chemosensation in this species. Here, we used next-generation sequencing (454 and Illumina) on different tissues from adult and larvae, including chemosensory organs and female ovipositors, to describe the chemosensory transcriptome of S. nonagrioides and identify key molecular components of the pheromone production and detection systems. We identified a total of 68 candidate chemosensory genes in this species, including 31 candidate binding-proteins and 23 chemosensory receptors. In particular, we retrieved the three co-receptors Orco, IR25a and IR8a necessary for chemosensory receptor functioning. Focusing on the pheromonal communication system, we identified a new pheromone-binding protein in this species, four candidate pheromone receptors and 12 carboxylesterases as candidate acetate degrading enzymes. In addition, we identified enzymes putatively involved in S. nonagrioides pheromone biosynthesis, including a ∆11-desaturase and different acetyltransferases and reductases. RNAseq analyses and RT-PCR were combined to profile gene expression in different tissues. This study constitutes the first large scale description of chemosensory genes in S. nonagrioides. PMID:23781142

  9. Education of Doctor of Pharmacy Candidates as Mental Health Professionals.

    ERIC Educational Resources Information Center

    Hayes, Peggy A.; Rosenbluth, Sidney A.

    1980-01-01

    The University of Tennessee offers an educational program to prepare Doctor of Pharmacy candidates for clinical roles in mental health care. The program consists of two core curricular elements: a didactic module and a clinical clerkship that devotes equal time to inpatient and outpatient care. Clinical guidelines and pharmacist goals are…

  10. Association of candidate genes with antisocial drug dependence in adolescents

    PubMed Central

    Corley, Robin P.; Zeiger, Joanna S.; Crowley, Thomas; Ehringer, Marissa A.; Hewitt, John K.; Hopfer, Christian J.; Lessem, Jeffrey; McQueen, Matthew B.; Rhee, Soo Hyun; Smolen, Andrew; Stallings, Michael C.; Young, Susan E.; Krauter, Kenneth

    2008-01-01

    The Colorado Center for Antisocial Drug Dependence (CADD) is using several research designs and strategies in its study of the genetic basis for antisocial drug dependence in adolescents. This study reports Single Nucleotide Polymorphism (SNP) association results from a Targeted Gene Assay (SNP chip) of 231 Caucasian male probands in treatment with antisocial drug dependence and a matched set of community controls. The SNP chip was designed to assay 1500 SNPs distributed across 50 candidate genes that have had associations with substance use disorders and conduct disorder. There was an average gene-wide inter-SNP interval of 3000 base pairs. After eliminating SNPs with poor signals and low minor allele frequencies, 60 nominally significant associations were found among the remaining 1073 SNPs in 18 of 49 candidate genes. Although none of the SNPs achieved genome-wide association significance levels (defined as p < .000001), two genes probed with multiple SNPs (OPRM1 and CHRNA2) emerged as plausible candidates for a role in antisocial drug dependence after gene-based permutation tests. The custom-designed SNP chip served as an effective and flexible platform for rapid interrogation of a large number of plausible candidate genes. PMID:18384978

  11. The Hidden Curriculum: Candidate Diversity in Educational Leadership Preparation

    ERIC Educational Resources Information Center

    Karanxha, Zorka; Agosto, Vonzell; Bellara, Aarti P.

    2014-01-01

    The authors describe a process of self-assessment attuned to equity and justice in the policies and practices that affect student diversity, namely, those associated with the selection of candidates. The disproportionate rate of rejection for applicants from underrepresented groups and the unsystematic process of applicant selection operated as…

  12. "Wishes" the Teacher Candidates Expressed in Communication with Themselves

    ERIC Educational Resources Information Center

    Çaliskan, Nihat

    2014-01-01

    The purpose of this study is to identify "the wish sentences" that teacher candidates create in the communication with themselves. The case study which is one of the type of qualitative research is utilized in this study. The study group is formed by 320 students studying in a university in central Anatolia. Data were collected by the…

  13. AN EFFICIENT AUTOMATED VALIDATION PROCEDURE FOR EXOPLANET TRANSIT CANDIDATES

    SciTech Connect

    Morton, Timothy D.

    2012-12-10

    Surveys searching for transiting exoplanets have found many more candidates than they have been able to confirm as true planets. This situation is especially acute with the Kepler survey, which has found over 2300 candidates but has to date confirmed only a small fraction of them as planets. I present here a general procedure that can quickly be applied to any planet candidate to calculate its false positive probability. This procedure takes into account the period, depth, duration, and shape of the signal; the colors of the target star; arbitrary spectroscopic or imaging follow-up observations; and informed assumptions about the populations and distributions of field stars and multiple-star properties. Applying these methods to a sample of known Kepler planets, I demonstrate that many signals can be validated with very limited follow-up observations: in most cases with only a spectrum and an adaptive optics image. Additionally, I demonstrate that this procedure can reliably identify false positive signals. Because of the computational efficiency of this analysis, it is feasible to apply it to all Kepler planet candidates in the near future, and it will streamline the follow-up efforts for Kepler and other current and future transit surveys.

  14. Assessing Pre-Service Candidates' Web-Based Electronic Portfolios.

    ERIC Educational Resources Information Center

    Lamson, Sharon; Thomas, Kelli R.; Aldrich, Jennifer; King, Andy

    This paper describes processes undertaken by Central Missouri State University's Department of Curriculum and Instruction to prepare teacher candidates to create Web-based professional portfolios, Central's expectations for content coverage within the electronic portfolios, and evaluation procedures. It also presents data on portfolio construction…

  15. Sleeping in or Selecting out? Candidates' Absence from GCSE Examinations

    ERIC Educational Resources Information Center

    Chamberlain, Suzanne

    2008-01-01

    For a multitude of reasons candidates do not always complete all assessments in the examinations they are entered for. Using examination data across a range of GCSE specifications offered by the Assessment and Qualifications Alliance, this article details the impact of "unaccepted" absence on educational attainment, and explores absence by mode of…

  16. Candidates in Educational Leadership Graduate Programs. Implications from UCEA

    ERIC Educational Resources Information Center

    University Council for Educational Administration, 2011

    2011-01-01

    In 2009, an essential new Handbook was published by UCEA, the "Handbook of Research on the Education of School Leaders." The handbook provides a rich resource for researchers, policy makers and those who prepare educational leaders. The chapter discussed in this issue of "Implications" addresses the leadership candidates enrolled in educational…

  17. Identifying and Assessing Dispositions of Educational Leadership Candidates

    ERIC Educational Resources Information Center

    Melton, Teri; Mallory, Barbara J.; Green, James

    2010-01-01

    The purpose of this study was to identify educational leadership programs' procedures for the identification and assessment of leadership dispositions. The findings of this cross sectional survey indicated that there is little consistency in practice in defining and assessing dispositions of leadership candidates. While findings indicated that the…

  18. What Rural Superintendents in Ohio Value in New Teacher Candidates

    ERIC Educational Resources Information Center

    Smith, Richard D., Jr.

    2012-01-01

    The purpose of this study was to have a better understanding of what rural superintendents are looking for in new first-year teachers, and to provide that information to future teaching candidates and colleges of education that are preparing teachers for the 21st Century classroom. Over the past twenty years, superintendents have not changed in…

  19. GOP Candidates Eye Scaling Back Federal K-12 Role

    ERIC Educational Resources Information Center

    Klein, Alyson

    2012-01-01

    Though education has played second fiddle so far to other domestic issues in the race for the Republican presidential nomination, the narrowing field includes GOP candidates with compatible views on scaling back the federal role in K-12, but big contrasts in policy specifics and experience. President Barack Obama, meanwhile, is expected to put a…

  20. Primary School Teacher Candidates' Geometric Habits of Mind

    ERIC Educational Resources Information Center

    Köse, Nilu¨fer Y.; Tanisli, Dilek

    2014-01-01

    Geometric habits of mind are productive ways of thinking that support learning and using geometric concepts. Identifying primary school teacher candidates' geometric habits of mind is important as they affect the development of their future students' geometric thinking. Therefore, this study attempts to determine primary school…

  1. Principals' and Cooperating Teachers' Expectations of Teacher Candidates

    ERIC Educational Resources Information Center

    Bigham, Sarah G.; Hively, Dorothy E.; Toole, Georgiann H.

    2014-01-01

    This study examined public school partners' expectations of teacher candidates and beginning teachers and the qualities that principals consider most important when hiring new teachers. Teachers in Maryland, West Virginia and Virginia (N = 130) responded to 37 Likert-style survey questions based upon the 100 school principals' interview questions…

  2. Genomic loci and candidate genes underlying inflammatory nociception

    PubMed Central

    Nair, Harsha K.; Hain, Heather; Quock, Raymond M.; Philip, Vivek M.; Chesler, Elissa J.; Belknap, John K.; Lariviere, William R.

    2011-01-01

    Heritable genetic factors contribute significantly to inflammatory nociception. To determine candidate genes underlying inflammatory nociception, the current study used a mouse model of abdominal inflammatory pain. BXD recombinant inbred (RI) mouse strains were administered the intraperitoneal (IP) acetic acid test and genome-wide quantitative trait locus (QTL) mapping was performed on the mean number of abdominal contraction and extension movements in three distinct groups of BXD RI mouse strains in two separate experiments. Combined mapping results detected two QTLs on chromosomes (Chr) 3 and 10 across experiments and groups of mice; an additional sex-specific QTL was detected on Chr 16. The results replicate previous findings of a significant QTL, Nociq2, on distal Chr 10 for formalin-induced inflammatory nociception and will aid in identification of the underlying candidate genes. Comparisons of sensitivity to IP acetic acid in BXD RI mouse strains with microarray mRNA transcript expression profiles in specific brain areas detected covarying expression of candidate genes that are also found in the detected QTL confidence intervals. The results indicate that common and distinct genetic mechanisms underlie heritable sensitivity to diverse inflammatory insults, and provide a discrete set of high priority candidate genes to investigate further in rodents and human association studies. PMID:21195549

  3. The Teacher Work Sample: Candidate and Mentor Perceptions

    ERIC Educational Resources Information Center

    Bell, David; Spelman, Maureen; Mackley, Holly; Zhao, Liang

    2009-01-01

    Elementary education faculty at this university embedded a Teacher Work Sample (TWS) performance-based assessment into the student teaching experience to assess candidates' ability to impact student learning as required by recent accreditation reforms. The authors conducted an internal evaluation of the TWS for the purposes of strengthening not…

  4. Preparing Teachers for Diverse Learners: Assessing Teacher Candidates' Dispositions

    ERIC Educational Resources Information Center

    Northington, Vera Ann

    2011-01-01

    The National Council for Accreditation for Teacher Education (NCATE) recommended teacher preparation programs measure teacher candidates' disposition toward diverse learners. The conduction of the quantitative cross-sectional survey design utilized the Quick Discrimination Index Survey (QDI), a Likert-type tool that used reversed or negatively…

  5. The Impact of Notebooking on Teacher Candidates' Construction of Knowledge

    ERIC Educational Resources Information Center

    Mohr, Jennifer A.; Raisor, Jill M.; Thomas, Jeff A.

    2014-01-01

    Teacher education preparation programs must adapt to changing science education reform movements that identify notebooking as an effective means to increase children's' science process skills and content knowledge. This study addresses the question, "What are the structures and thinking processes that teacher candidates utilize when writing…

  6. BACTERIAL PATHOGENIC RESEARCH IN RESPONSE TO CONTAMINANT CANDIDATE LIST NEEDS

    EPA Science Inventory

    The Safe Drinking Water Act, as amended in 1996, requires EPA to establish a Contaminant Candidate List (CCL) of unregulated microbiological and chemical contaminants to aid in priority setting for the Agency's drinking water program. At predetermined intervals the Agency must s...

  7. Linguistic and Cultural Adaptation of Internationally Educated Teacher Candidates

    ERIC Educational Resources Information Center

    Faez, Farahnaz

    2010-01-01

    This paper reports on findings of a qualitative study that explored the experiences, needs and challenges of internationally educated teacher candidates (IETCs) in a large metropolitan university in Canada. Interviews were conducted with IETCs as well as the teacher educator working with them. Findings revealed that IETCs required additional…

  8. Documenting Teacher Candidates' Professional Growth through Performance Evaluation

    ERIC Educational Resources Information Center

    Brown, Elizabeth Levine; Suh, Jennifer; Parsons, Seth A.; Parker, Audra K.; Ramirez, Erin M.

    2015-01-01

    In the United States, colleges of education are responding to demands for increased accountability. The purpose of this article is to describe one teacher education program's implementation of a performance evaluation tool during final internship that measures teacher candidates' development across four domains: Planning and Preparation,…

  9. 28 CFR 105.14 - Risk assessment for candidates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Risk assessment for candidates. 105.14 Section 105.14 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CRIMINAL HISTORY BACKGROUND CHECKS Aviation Training for Aliens and Other Designated Individuals § 105.14 Risk assessment...

  10. 28 CFR 105.14 - Risk assessment for candidates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Risk assessment for candidates. 105.14 Section 105.14 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CRIMINAL HISTORY BACKGROUND CHECKS Aviation Training for Aliens and Other Designated Individuals § 105.14 Risk assessment...

  11. 28 CFR 105.14 - Risk assessment for candidates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Risk assessment for candidates. 105.14 Section 105.14 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CRIMINAL HISTORY BACKGROUND CHECKS Aviation Training for Aliens and Other Designated Individuals § 105.14 Risk assessment...

  12. Early Childhood Teacher Candidates Evaluate Computer Software for Young Children

    ERIC Educational Resources Information Center

    Aldrich, Jennifer

    2002-01-01

    The proliferation of computer software for young children necessitates that early childhood teachers have the knowledge and skills needed to evaluate and select developmentally appropriate software. This article describes the manner in which one university prepares early childhood teacher candidates to analyze software for the young children in…

  13. Teacher Candidates' Perceptions of Scientists: Images and Attributes

    ERIC Educational Resources Information Center

    McCarthy, Deborah

    2015-01-01

    The masculine image of scientists as elderly men wearing white coats and glasses, working alone in the laboratory has been documented since the 1950s. Because it is important that teacher candidates have a scientifically literate image of scientists due to the impact they have on their future students, this investigation is salient. This study…

  14. Preparing Teacher Candidates for Family-School Partnerships

    ERIC Educational Resources Information Center

    de Bruïne, Erica J.; Willemse, T. Martijn; D'Haem, Jeanne; Griswold, Peter; Vloeberghs, Lijne; van Eynde, Sofie

    2014-01-01

    Previous research indicates that, while parent involvement promotes student achievement, how teacher candidates are prepared to establish family-school partnerships (FSP) is not well documented and the roles of teacher educators are often neglected. Explorative studies including curriculum analysis and focus groups of primary and secondary teacher…

  15. Teacher Candidates' Transformative Thinking on Issues of Social Justice

    ERIC Educational Resources Information Center

    Frederick, Rona; Cave, Agnes; Perencevich, Kathleen C.

    2010-01-01

    This article examined how teacher candidates' thoughts shifted regarding social inequity in a sophomore-level Foundations of Education course located in the mid-Atlantic region of the United States. First, we described in detail the teacher education program and course, as well as class simulations, school observations, course readings and class…

  16. 1990 astronaut candidate Chiao determines location during wilderness training

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Leroy Chiao determines his location in order to specify directions for a helicopter pickup during wilderness survival training at Fairchild Air Force Base. Chiao, one of 23 1990 Group 13 astronaut candidates, participated in the training near Spokane, Washington, 08-26-90 through 08-30-90.

  17. Single transit candidates from K2: detection and period estimation

    NASA Astrophysics Data System (ADS)

    Osborn, H. P.; Armstrong, D. J.; Brown, D. J. A.; McCormac, J.; Doyle, A. P.; Louden, T. M.; Kirk, J.; Spake, J. J.; Lam, K. W. F.; Walker, S. R.; Faedi, F.; Pollacco, D. L.

    2016-04-01

    Photometric surveys such as Kepler have the precision to identify exoplanet and eclipsing binary candidates from only a single transit. K2, with its 75 d campaign duration, is ideally suited to detect significant numbers of single-eclipsing objects. Here we develop a Bayesian transit-fitting tool (`Namaste: An Mcmc Analysis of Single Transit Exoplanets') to extract orbital information from single transit events. We achieve favourable results testing this technique on known Kepler planets, and apply the technique to seven candidates identified from a targeted search of K2 campaigns 1, 2 and 3. We find EPIC203311200 to host an excellent exoplanet candidate with a period, assuming zero eccentricity, of 540 ^{+410}_{-230} d and a radius of 0.51 ± 0.05RJup. We also find six further transit candidates for which more follow-up is required to determine a planetary origin. Such a technique could be used in the future with TESS, PLATO and ground-based photometric surveys such as NGTS, potentially allowing the detection of planets in reach of confirmation by Gaia.

  18. Candidate new rotavirus species in sheltered dogs, Hungary.

    PubMed

    Mihalov-Kovács, Eszter; Gellért, Ákos; Marton, Szilvia; Farkas, Szilvia L; Fehér, Enikő; Oldal, Miklós; Jakab, Ferenc; Martella, Vito; Bányai, Krisztián

    2015-04-01

    We identified unusual rotavirus strains in fecal specimens from sheltered dogs in Hungary by viral metagenomics. The novel rotavirus species displayed limited genome sequence homology to representatives of the 8 rotavirus species, A-H, and qualifies as a candidate new rotavirus species that we tentatively named Rotavirus I. PMID:25811414

  19. Further SAO RAS spectral classification of SN candidates.

    NASA Astrophysics Data System (ADS)

    Fatkhullin, T. A.; Moskvitin, A. S.

    2016-08-01

    We observed two SN candidates (AT 2016emj, AT 2016emb) with the BTA/Scorpio-I on the night of August, 3. Direct images in the V band and long-slit spectra in the range of 3600-7600AA (resolution FWHM = 10A) were obtained.

  20. Spectroscopy of two PN candidates in IC10

    NASA Astrophysics Data System (ADS)

    Kniazev, A. Y.; Pustilnik, S. A.; Zucker, D. B.

    2008-03-01

    We present the results of the first spectroscopic observations of two planetary nebula (PN) candidates in the Local Group dwarf irregular galaxy IC10. Using several spectral classification diagrams, we show that the brightest PN candidate (PN7) is not a PN, but rather a compact HII region consisting of two components with low electron number densities. After the rejection of this PN candidate, the IC10 PN luminosity function cut-off becomes very close to the standard value. With the compiled spectroscopic data for a large number of extragalactic PNe, we analyse a series of diagnostic diagrams to generate quantitative criteria for separating PNe from unresolved HII regions. We show that, with the help of the diagnostic diagrams and the derived set of criteria, PNe can be distinguished from HII regions with an efficiency of ~99.6 per cent. With the obtained spectroscopic data, we confirm that another, 1.7 mag fainter PN candidate (PN9) is a genuine PN. We argue that, based on all currently available PNe data, IC10 is located at a distance of 725+63-33 kpc [distance modulus (m - M) = 24.30+0.18-0.10]. Based on observations obtained at the 6-m SAO RAS (Special Astrophysical Observatory of Russian Academy of Science) telescope. E-mail: akniazev@saao.ac.za (AYK); sap@sao.ru (SAP); zucker@ast.cam.ac.uk (DBZ)

  1. Health Potential of Female Candidates to the Professional Military Service

    ERIC Educational Resources Information Center

    Kaiser, Alicja; Sokolowski, Marek

    2011-01-01

    Study aim: To assess health and social characteristics of female candidates for professional officers and non-commissioned officers of Polish Army. Material and methods: All female students of officer and non-commissioned officer Military Academies (16 each) were studied in 2009. Two questionnaires were applied in the study: IPAQ (short) for…

  2. Teacher Candidates' Collaboration and Identity in Online Discussions

    ERIC Educational Resources Information Center

    Bryce, Nadine

    2014-01-01

    In an online context, without facial, verbal or gestural cues, establishing identities through naming social positions appeared essential to effective written communication for graduate pre-service teacher candidates enrolled in a course on literacy education for elementary students. As they engaged in small group asynchronous discussions about…

  3. Teacher Candidates' Accuracy of Beliefs regarding Childhood Interventions

    ERIC Educational Resources Information Center

    Bain, Sherry K.; Brown, Katherine Sager; Jordan, Kelli R.

    2009-01-01

    The authors examined the beliefs of 351 teacher candidates, from various levels of training, regarding the effectiveness of potential interventions for childhood disorders. They were primarily interested in participants' responses to three categories of interventions: (a) evidence-based, (b) controversial, and (c) primarily anecdotal. They found…

  4. Assessing School Principal Candidates: Perspectives of the Hiring Superintendents

    ERIC Educational Resources Information Center

    Kwan, Paula

    2012-01-01

    This paper examines the criteria used by recruiting bodies to assess potential candidates for the post of principal of a secondary school in Hong Kong. A quantitative methodology is used to identify what recruiters seek in applicants. The expectations that recruiters have when assessing applicants can be seen as a form of proxy for the elements…

  5. 28 CFR 105.14 - Risk assessment for candidates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Risk assessment for candidates. 105.14 Section 105.14 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CRIMINAL HISTORY BACKGROUND CHECKS Aviation Training for Aliens and Other Designated Individuals § 105.14 Risk assessment...

  6. Teacher Candidates' Attitudes to Using Oral History in History Education

    ERIC Educational Resources Information Center

    Demircioglu, Ebru

    2016-01-01

    The aim of this research is to determine the views of history teacher candidates towards an oral history project carried out in the Special Teaching Method Course of the history pedagogy program of the Fatih Faculty of Education (FFE) at Karadeniz Technical University in Turkey. An open-ended questionnaire and semi-structured interview were the…

  7. 28 CFR 105.14 - Risk assessment for candidates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Risk assessment for candidates. 105.14 Section 105.14 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CRIMINAL HISTORY BACKGROUND CHECKS Aviation Training for Aliens and Other Designated Individuals § 105.14 Risk assessment...

  8. Art, Music, and Movement Connections for Elementary Education Teacher Candidates

    ERIC Educational Resources Information Center

    Bohannon, R. Larry; McDowell, Carol

    2010-01-01

    Visual arts, movement, and music are all connected by common structural elements. The lesson described in this article was prepared so that teacher candidates in elementary education may make connections among music, movement, and the visual arts using an elemental integration approach. This lesson used visual art to introduce the concept of line…

  9. Effects of the Bush/Ferraro Debate on Candidate Characterization.

    ERIC Educational Resources Information Center

    Stamm, Keith R.

    A study was conducted to determine the cognitive effects on viewers of the debate between vice-presidential candidates George Bush and Geraldine Ferraro. Adult passengers (N=468) on the Washington State ferries were interviewed, 191 before the debate and 277 afterward. Of those interviewed after the debate, 168 reported watching the debate and 108…

  10. An Analysis of Changes in Voter Perception of Candidates' Positions.

    ERIC Educational Resources Information Center

    Anderson, James A.; And Others

    In an effort to discover the effects of mass media on viewer perception of candidates' positions, tests were administered to 10 to 12 families at each of five locations across the country immediately following each of the 1976 Carter-Ford debates. Sixteen statements were drawn from the presidential platform of each party and each statement was…

  11. 11 CFR 110.8 - Presidential candidate expenditure limitations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... section shall be increased in accordance with 11 CFR 110.17. (3) Voting age population is defined at 11 CFR 110.18. (b) The expenditure limitations shall not be considered violated if, after the date of the... expenditure limitation under 11 CFR 9035.1. (d)(1) If an individual is a candidate for more than one...

  12. Encouraging Agitation: Teaching Teacher Candidates to Confront Words that Wound

    ERIC Educational Resources Information Center

    Staples, Jeanine M.

    2010-01-01

    In this analytic conceptual essay, and from her standpoint as an African American woman teacher/researcher, the author presents a rich description of a personal sensibility and promising professional practice for literacy educators and those who prepare Reading/English/Language Arts teacher candidates for service among students who are…

  13. Selection and Elimination of Candidates in Counselor Education Programs

    ERIC Educational Resources Information Center

    Redfering, David L.; Biasco, Frank

    1976-01-01

    This study compared actual with ideal procedures in the selection and elimination of candidates in counselor education programs. A two-factor analysis for each category (selection and elimination) resulted in some significant differences between the actual and ideal procedures in both selection and elimination. (Author)

  14. Teacher Candidates' Opinions on Erasmus Student Exchange Program

    ERIC Educational Resources Information Center

    Unlu, Ihsan

    2015-01-01

    This study contains teacher candidates' opinions who spent a portion of their educational career abroad as participants in the Erasmus Program regarding the academic, cultural, and personal gains of the program. Using the Quantitative Research Method, this study focuses on phenomena that researchers are aware of, but on which they do not have…

  15. Supporting Clinical Practice Candidates in Learning Community Development

    ERIC Educational Resources Information Center

    DeJarnette, Nancy K.; Sudeck, Maria

    2015-01-01

    The purpose of this qualitative research study was to monitor pre-service teacher candidates' progression and implementation of the learning community philosophy along with classroom management strategies. The study took place during their final semester of clinical practice. Data were collected from self-reports, surveys, university supervisor…

  16. TECHNICAL BASIS FOR A CANDIDATE BUILDING MATERIALS RADIUM STANDARD

    EPA Science Inventory

    The report summarizes the technical basis for a candidate building materials radium standard. It contains the standard and a summary of the technical basis for the standard. (NOTE: The Florida Radon Research Program (FRRP), sponsored by the Environmental Protection Agency and the...

  17. Identity Development among Pre-Service Teacher Candidates

    ERIC Educational Resources Information Center

    Lerseth, Kathryn Ann

    2013-01-01

    This case study examined teacher identity development among four pre-service teacher candidates during their student teaching experience. Guided by three complementary theoretical frameworks for investigating teacher professional identities (e.g., Gee, 2000-2001; Beijaard, Meijer, & Verloop; 2004; Moje & Luke, 2009), the study focused on…

  18. Investigating Change in Field Sites through Mentor and Candidate Dialogues

    ERIC Educational Resources Information Center

    Kroeger, Janice; Pech, Sandra; Cope, Jennifer

    2009-01-01

    The work of teacher candidates matters in particular ways to the quality of children's experiences and environments when they teach in preschools. We conducted a mixed-method study with survey, interviews, focus groups, and photographic documentation of classroom spaces, and theorized findings through Bahktin's dialogism and the notion of figured…

  19. Testing of Candidate Batteries for Global Positioning System

    NASA Technical Reports Server (NTRS)

    Barnes, J. A.; Debold, F. C.; Bis, R. F.; Buchholz, S.; Davis, P.; Kowalchik, L. A.

    1984-01-01

    Three lithium batteries proposed as candidates for use in the Global Positioning System are studied. The batteries are discharged at several rates and temperatures both before and after environmental testing. Batteries are heated inside a closed chamber until they vent. Samples of the vented gases are analyzed for components which might be toxic. The test results raise concerns about each of the proposed batteries.

  20. Immunoproteomic Analysis of Potential Serum Biomarker Candidates in Human Glaucoma

    PubMed Central

    Tezel, Gülgün; Thornton, Ivey L.; Tong, Melissa G.; Luo, Cheng; Yang, Xiangjun; Cai, Jian; Powell, David W.; Soltau, Joern B.; Liebmann, Jeffrey M.; Ritch, Robert

    2012-01-01

    Purpose. Evidence supporting the immune system involvement in glaucoma includes increased titers of serum antibodies to retina and optic nerve proteins, although their pathogenic importance remains unclear. This study using an antibody-based proteomics approach aimed to identify disease-related antigens as candidate biomarkers of glaucoma. Methods. Serum samples were collected from 111 patients with primary open-angle glaucoma and an age-matched control group of 49 healthy subjects without glaucoma. For high-throughput characterization of antigens, serum IgG was eluted from five randomly selected glaucomatous samples and analyzed by linear ion trap mass spectrometry (LC-MS/MS). Serum titers of selected biomarker candidates were then measured by specific ELISAs in the whole sample pool (including an additional control group of diabetic retinopathy). Results. LC-MS/MS analysis of IgG elutes revealed a complex panel of proteins, including those detectable only in glaucomatous samples. Interestingly, many of these antigens corresponded to upregulated retinal proteins previously identified in glaucomatous donors (or that exhibited increased methionine oxidation). Moreover, additional analysis detected a greater immunoreactivity of the patient sera to glaucomatous retinal proteins (or to oxidatively stressed cell culture proteins), thereby suggesting the importance of disease-related protein modifications in autoantibody production/reactivity. As a narrowing-down strategy for selection of initial biomarker candidates, we determined the serum proteins overlapping with the retinal proteins known to be up-regulated in glaucoma. Four of the selected 10 candidates (AIF, cyclic AMP-responsive element binding protein, ephrin type-A receptor, and huntingtin) exhibited higher ELISA titers in the glaucomatous sera. Conclusions. A number of serum proteins identified by this immunoproteomic study of human glaucoma may represent diseased tissue-related antigens and serve as candidate