5,676 research outputs found

    The Effects Of Self-referencing In The Processing Of Linear Ordering Relations

    Get PDF
    The purpose of the present research was to investigate the effects of self referencing in the processing of linear ordering relations in a task designed to simulate certain aspects of classroom mathematics instruction. In each of three experiments, undergraduate students enrolled in an introductory psychology course were asked to read a series of paragraphs each of which contained a 5-term linear ordering relation (e.g., {dollar}\rm A\u3eB\u3eC\u3eD\u3eE).{dollar} After this information was encoded, subjects were asked to make pair-wise comparisons of these 5 terms. Two major factors were tested: the inclusion of a You term (Self-Referencing) among the 5 terms, and the position of the You term (Position of Self-Referencing) in the ordering. In Experiment 1, the You term was placed at three positions: first, third and fifth. Experiment 2 extended the investigation to all five positions. Experiment 3 was designed to replicate the findings from the previous two experiments and to increase the power of statistical tests of the Self-Referencing effect. The results of all three experiments were consistent. Self-Referencing did not result in a difference in overall performance. However, the Position effect and the interaction of Self-Referencing with other variables demonstrated that self-referencing had a strong impact on cognitive processing. When the You term was included, subjects appeared to use it as a focus in organizing information, and the further away this self-focus point was from the endpoints, the worse performance became. When test questions were related to the self, reaction times were shorter, whereas when questions did not involve a self term, reaction times were slower. The endpoint effect and the distance effect reported in previous research were also tested. It was found that when the You term was included in various positions in the linear ordering, the endpoint effect changed accordingly. The distance effect was not evident in the present research. Implications for educational and cognitive research were discussed

    Near-IR studies of recurrent nova V745 Scorpii during its 2014 outburst

    Full text link
    The recurrent nova (RN) V745 Scorpii underwent its third known outburst on 2014 February 6. Infrared monitoring of the eruption on an almost daily basis, starting from 1.3d after discovery, shows the emergence of a powerful blast wave generated by the high velocity nova ejecta exceeding 4000 kms1^{-1} plowing into its surrounding environment. The temperature of the shocked gas is raised to a high value exceeding 108^{8}K immediately after outburst commencement. The energetics of the outburst clearly surpass those of similar symbiotic systems like RS Oph and V407 Cyg which have giant secondaries. The shock does not show a free-expansion stage but rather shows a decelerative Sedov-Taylor phase from the beginning. Such strong shockfronts are known to be sites for γ\gamma ray generation. V745 Sco is the latest nova, apart from five other known novae, to show γ\gamma ray emission. It may be an important testbed to resolve the crucial question whether all novae are generically γ\gamma ray emitters by virtue of having a circumbinary reservoir of material that is shocked by the ejecta rather than γ\gamma ray generation being restricted to only symbiotic systems with a shocked red giant (RG) wind. The lack of a free-expansion stage favors V745 Sco to have a density enhancement around the white dwarf (WD), above that contributed by a RG wind. Our analysis also suggests that the WD in V745 Sco is very massive and a potential progenitor for a future SN Ia explosion.Comment: To appear in ApJ (Letters

    Unraveling the Infrared Transient VVV-WIT-06: The Case for the Origin as a Classical Nova

    Get PDF
    Indexación: Scopus.E.Y.H. acknowledges the support provided by the National Science Foundation under Grant No. AST-1613472 and by the Florida Space Grant Consortium. L.G. acknowledges support from the FINCA visitor programme. The research work at the Physical Research Laboratory is funded by the Department of Space, Government of India. Facility: Magellan: Baade(FIRE).The enigmatic near-infrared transient VVV-WIT-06 underwent a large-amplitude eruption of unclear origin in 2013 July. Based on its light curve properties and late-time post-outburst spectra, various possibilities have been proposed in the literature for the origin of the object, namely a Type I supernova, a classical nova (CN), or a violent stellar merger event. We show that, of these possibilities, an origin in a CN outburst convincingly explains the observed properties of VVV-WIT-06. We estimate that the absolute K-band magnitude of the nova at maximum was M k = -8.2 ±0.5, its distance d = 13.35 ±2.18 kpc, and the extinction A v = 15.0 ±0.55 mag. © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-4357/aae5d

    Experimental Studies of Low-field Landau Quantization in Two-dimensional Electron Systems in GaAs/AlGaAs Heterostructures

    Full text link
    By applying a magnetic field perpendicular to GaAs/AlGaAs two-dimensional electron systems, we study the low-field Landau quantization when the thermal damping is reduced with decreasing the temperature. Magneto-oscillations following Shubnikov-de Haas (SdH) formula are observed even when their amplitudes are so large that the deviation to such a formula is expected. Our experimental results show the importance of the positive magneto-resistance to the extension of SdH formula under the damping induced by the disorder.Comment: 9 pages, 3 figure

    Early Observations and Analysis of the Type 1a SN 2014J in M82

    Get PDF
    We present optical and near infrared (NIR) observations of the nearby Type Ia SN 2014J. Seventeen optical and 23 NIR spectra were obtained from 10 days before (-10d) to 10 days after (+10d) the time of maximum B-band brightness. The relative strengths of absorption features and their patterns of development can be compared at one day intervals throughout most of this period. Carbon is not detected in the optical spectra, but we identify C I lambda 1.0693 in the NIR spectra. Mg II lines with high oscillator strengths have higher initial velocities than other Mg II lines. We show that the velocity differences can be explained by differences in optical depths due to oscillator strengths. The spectra of SN 2014J show that it is a normal SN Ia, but many parameters are near the boundaries between normal and high-velocity subclasses. The velocities for OI, Mg II, Si II, S Ca a, and Fell suggest that SN 2014J has a layered structure with little or no mixing. That result is consistent with the delayed detonation explosion models. We also report photometric observations, obtained from -10d to +29d, in the UBVRIJH and K-s bands. The template fitting package SNooPy is used to interpret the light curves and to derive photometric parameters. Using R-v = 1.46, which is consistent with previous studies, SNooPy finds that A(v) = 1.80 for E(B - V)(host) = 1.23 +/- 0.06 mag. The maximum B-band brightness of -19.19 +/- 0.10 mag was reached on February 1.74 UT +/- 0.13 days and the supernova has a decline parameter, Delta m(15), of 1.12 +/- 0.02 mag

    Static and dynamic properties of large polymer melts in equilibrium

    Full text link
    We present a detailed study of the static and dynamic behavior of long semiflexible polymer chains in a melt. Starting from previously obtained fully equilibrated high molecular weight polymer melts [{\it Zhang et al.} ACS Macro Lett. 3, 198 (2014)] we investigate their static and dynamic scaling behavior as predicted by theory. We find that for semiflexible chains in a melt, results of the mean square internal distance, the probability distributions of the end-to-end distance, and the chain structure factor are well described by theoretical predictions for ideal chains. We examine the motion of monomers and chains by molecular dynamics simulations using the ESPResSo++ package. The scaling predictions of the mean squared displacement of inner monomers, center of mass, and relations between them based on the Rouse and the reptation theory are verified, and related characteristic relaxation times are determined. Finally we give evidence that the entanglement length Ne,PPAN_{e,PPA} as determined by a primitive path analysis (PPA) predicts a plateau modulus, GN0=45(ρkBT/Ne)G_N^0=\frac{4}{5}(\rho k_BT/N_e), consistent with stresses obtained from the Green-Kubo relation. These comprehensively characterized equilibrium structures, which offer a good compromise between flexibility, small NeN_e, computational efficiency, and small deviations from ideality provide ideal starting states for future non-equilibrium studies.Comment: 13 pages, 10 figures, to be published in J. Chem. Phys. (2016
    corecore