17,098 research outputs found

    PLTTER user's guide

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    The PLTTER graphics system, which is part of CDDMS is discussed. CDDMS is a comprehensive system for data basing and subsequent plotting of data acquired during wind tunnel tests or from computational flow analyses. The PLTTER is a system which creates report-quality plots of data which is stored on a CDDMS data base. The Requests file system allows plot-controlling information to be arranged in the way which is most appropriate for any application. The PLTTER system features many capabilities which are especially useful when plotting wind tunnel data. The PLTTER offers a variety of page formats, different grid options and parametric curve fitting algorithms, and a powerful legend capability to identify relevant information about individual curves. One or more plots on a page can be suppressed if desired so that an established page format can be maintained. Final plot output may be standard Versatec plots, QMS Laser printer plots, or microfiche

    Views of Coaching Practice Expressed by School-Based Coaches

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    This study reports on the views of coaching expressed by school-based coaches and coaching experts in response to observing the practice of a novice coach featured in a video. Researchers hypothesized that a coach participant\u27s observations about another coach\u27s practice would be a useful tool for examining participants\u27 beliefs about coaching. Researchers compared responses from school-based coaches to the responses of coaching experts and views expressed in leading coaching literature in order to examine the variation in school-based coaches\u27 views. Analysis of responses from both practicing coaches and coaching experts revealed eight themes that describe components of the videotaped coaching cycle: 1) coaching relationships; 2) the use of praise by the coach; 3) discussions of student learning; 4) how coaches respond to teachers\u27 questions; 5) how coaches prompt reflection; 6) how coaches address teacher knowledge and learning; 7) discussions of mathematics content; and, 8) facilitation of the coaching session. The analysis also revealed that these themes correspond to accepted domains of coaching knowledge reported in the coaching literature

    557 GHz Observations of Water Vapor Outflows from VY CMa and W Hydrae

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    We report the first detection of thermal water vapor emission in the 557 GHz, 110−1011_{10} - 1_{01} ground state transition of ortho-H2_2O toward VY Canis Majoris. In observations obtained with the Submillimeter Wave Astronomy Satellite (SWAS), we measured a flux of ∌450\sim 450 Jy, in a spectrally resolved line centered on a velocity vLSR=25v_{LSR} = 25 km s−1^{-1} with a full width half maximum of ∌35\sim 35 km s−1^{-1}, somewhat dependent on the assumed line shape. We analyze the line shape in the context of three different radial outflow models for which we provide analytical expressions. We also detected a weaker 557 GHz emission line from W Hydrae. We find that these and other H2_2O emission line strengths scale as suggested by Zubko and Elitzur (2000).Comment: Astrophysical Journal Letters, accepte

    Dust masses for SN 1980K, SN1993J and Cassiopeia A from red-blue emission line asymmetries

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    We present Monte Carlo line transfer models that investigate the effects of dust on the very late time emission line spectra of the core collapse supernovae SN 1980K and SN 1993J and the young core collapse supernova remnant Cassiopeia A. Their blue-shifted emission peaks, resulting from the removal by dust of redshifted photons emitted from the far sides of the remnants, and the presence of extended red emission wings are used to constrain dust compositions and radii and to determine the masses of dust in the remnants. We estimate dust masses of between 0.08 – 0.15 M⊙ for SN 1993J at year 16, 0.12 – 0.30 M⊙ for SN 1980K at year 30 and ∌1.1 M⊙ for Cas A at year ∌330. Our models for the strong oxygen forbidden lines of Cas A require the overall modelled profiles to be shifted to the red by between 700 – 1000 km s−1, consistent with previous estimates for the shift of the dynamical centroid of this remnant

    Variability Tests for Intrinsic Absorption Lines in Quasar Spectra

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    Quasar spectra have a variety of absorption lines whose origins range from energetic winds expelled from the central engines to unrelated, intergalactic clouds. We present multi-epoch, medium resolution spectra of eight quasars at z~2 that have narrow ``associated'' absorption lines (AALs, within ±\pm5000 km s^{-1} of the emission redshift). Two of these quasars were also known previously to have high-velocity mini-broad absorption lines (mini-BALs). We use these data, spanning ~17 years in the observed frame with two to four observations per object, to search for line strength variations as an identifier of absorption that occurs physically near (``intrinsic'' to) the central AGN. Our main results are the following: Two out of the eight quasars with narrow AALs exhibit variable AAL strengths. Two out of two quasars with high-velocity mini-BALs exhibit variable mini-BAL strengths. We also marginally detect variability in a high-velocity narrow absorption line (NAL) system, blueshifted \~32,900 km s^{-1}$ with respect to the emission lines. No other absorption lines in these quasars appeared to vary. The outflow velocities of the variable AALs are 3140 km s^{-1} and 1490 km s^{-1}. The two mini-BALs identify much higher velocity outflows of ~28,400 km s^{-1} and ~52,000 km s^{-1}. Our temporal sampling yields upper limits on the variation time scales from 0.28 to 6.1 years in the quasar rest frames. The corresponding minimum electron densities in the variable absorbers, based on the recombination time scale, are \~40,000 cm^{-3} to ~1900 cm^{-3}. The maximum distances of the absorbers from the continuum source, assuming photoionization with no spectral shielding, range from ~1.8 kpc to ~7 kpc.Comment: 16 pages, 4 figures, ApJ, accepte

    Biased tomography schemes: an objective approach

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    We report on an intrinsic relationship between the maximum-likelihood quantum-state estimation and the representation of the signal. A quantum analogy of the transfer function determines the space where the reconstruction should be done without the need for any ad hoc truncations of the Hilbert space. An illustration of this method is provided by a simple yet practically important tomography of an optical signal registered by realistic binary detectors.Comment: 4 pages, 3 figures, accepted in PR

    Perceptions of Family Violence: Are Companion Animals in the Picture?

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    Service and education organizations such as the ASPCA claim a connection between family violence against children and companiion animals, but to what extent does the general public share this perception? Sixty-three undergraduates rated their certainty about perceiving family violence using 60 pictures witrh differing potential targets of family violence. Participants showed stronger certainty when the target was a child than when the target was a companion animal, but ratings for companion animals averaged above the midpoint of the scale used. Interview questions were used to obtain information about child recollections of joint discipline situations in which children received punishment for what companion animals did, or vice versa. Thirty-four participants recalled such situations, some of which resulted in the death or discarding of a family's companion animal. The majority of participants affirmed a connection between violence against children and companion animals in the family, with some giving credit for that insight to their taking part in the study
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