16,358 research outputs found

    Temporal markers of prosodic boundaries in children's speech production

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    It is often thought that the ability to use prosodic features accurately is mastered in early childhood. However, research to date has produced conflicting evidence, notably about the development of children's ability to mark prosodic boundaries. This paper investigates (i) whether, by the age of eight, children use temporal boundary features in their speech in a systematic way, and (ii) to what extent adult listeners are able to interpret their production accurately and unambiguously. The material consists of minimal pairs of utterances: one utterance includes a compound noun, in which there is no prosodic boundary after the first noun, e.g. ‘coffee-cake and tea’, while the other utterance includes simple nouns, separated by a prosodic boundary, e.g. ‘coffee, cake and tea’. Ten eight-year-old children took part, and their productions were rated by 23 adult listeners. Two phonetic exponents of prosodic boundaries were analysed: pause duration and phrase-final lengthening. The results suggest that, at the age of 8, there is considerable variability among children in their ability to mark phrase boundaries of the kind analysed in the experiment, with some children failing to differentiate between the members of the minimal pairs reliably. The differences between the children in their use of boundary features were reflected in the adults' perceptual judgements. Both temporal cues to prosodic boundaries significantly affected the perceptual ratings, with pause being a more salient determinant of ratings than phrase-final lengthening

    Comparative analysis of rigidity across protein families

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    We present a comparative study in which 'pebble game' rigidity analysis is applied to multiple protein crystal structures, for each of six different protein families. We find that the main-chain rigidity of a protein structure at a given hydrogen bond energy cutoff is quite sensitive to small structural variations, and conclude that the hydrogen bond constraints in rigidity analysis should be chosen so as to form and test specific hypotheses about the rigidity of a particular protein. Our comparative approach highlights two different characteristic patterns ('sudden' or 'gradual') for protein rigidity loss as constraints are removed, in line with recent results on the rigidity transitions of glassy networks

    EAGLE ISS - A modular twin-channel integral-field near-IR spectrograph

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    The ISS (Integral-field Spectrograph System) has been designed as part of the EAGLE Phase A Instrument Study for the E-ELT. It consists of two input channels of 1.65x1.65 arcsec field-of-view, each reconfigured spatially by an image-slicing integral-field unit to feed a single near-IR spectrograph using cryogenic volume-phase-holographic (VPH) gratings to disperse the image spectrally. A 4k x 4k array detector array records the dispersed images. The optical design employs anamorphic magnification, image slicing, VPH gratings scanned with a novel cryo-mechanism and a three-lens camera. The mechanical implementation features IFU optics in Zerodur, a modular bench structure and a number of high-precision cryo-mechanisms.Comment: 12 pages, to be published in Proc SPIE 7735: Ground-based & Airborne Instrumentation for Astronomy II

    A new approach to the inverse problem for current mapping in thin-film superconductors

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    A novel mathematical approach has been developed to complete the inversion of the Biot-Savart law in one- and two-dimensional cases from measurements of the perpendicular component of the magnetic field using the well-developed Magneto-Optical Imaging technique. Our approach, especially in the 2D case, is provided in great detail to allow a straightforward implementation as opposed to those found in the literature. Our new approach also refines our previous results for the 1D case [Johansen et al., Phys. Rev. B 54, 16264 (1996)], and streamlines the method developed by Jooss et al. [Physica C 299, 215 (1998)] deemed as the most accurate if compared to that of Roth et al. [J. Appl. Phys. 65, 361 (1989)]. We also verify and streamline the iterative technique, which was developed following Laviano et al. [Supercond. Sci. Technol. 16, 71 (2002)] to account for in-plane magnetic fields caused by the bending of the applied magnetic field due to the demagnetising effect. After testing on magneto-optical images of a high quality YBa2Cu3O7 superconducting thin film, we show that the procedure employed is effective

    Anomalous Phase Transition in Strained SrTiO3_3 Thin Films

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    We have studied the cubic to tetragonal phase transition in epitaxial SrTiO3_3 films under various biaxial strain conditions using synchrotron X-ray diffraction. Measuring the superlattice peak associated with TiO6_6 octahedra rotation in the low temperature tetragonal phase indicates the presence of a phase transition whose critical temperature is a strong function of strain, with TC_C as much as 50K above the corresponding bulk temperature. Surprisingly, the lattice constants evolve smoothly through the transition with no indication of a phase change. This signals an important change in the nature of the phase transition due to the epitaxy strain and substrate clamping effect. The internal degrees of freedom (TiO6_6 rotations) have become uncoupled from the overall lattice shape.Comment: 4 pages, 3 figures, REVTeX

    Measuring Metacognition in Cancer: Validation of the Metacognitions Questionnaire 30 (MCQ-30)

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    Objective The Metacognitions Questionnaire 30 assesses metacognitive beliefs and processes which are central to the metacognitive model of emotional disorder. As recent studies have begun to explore the utility of this model for understanding emotional distress after cancer diagnosis, it is important also to assess the validity of the Metacognitions Questionnaire 30 for use in cancer populations. Methods 229 patients with primary breast or prostate cancer completed the Metacognitions Questionnaire 30 and the Hospital Anxiety and Depression Scale pre-treatment and again 12 months later. The structure and validity of the Metacognitions Questionnaire 30 were assessed using factor analyses and structural equation modelling. Results Confirmatory and exploratory factor analyses provided evidence supporting the validity of the previously published 5-factor structure of the Metacognitions Questionnaire 30. Specifically, both pre-treatment and 12 months later, this solution provided the best fit to the data and all items loaded on their expected factors. Structural equation modelling indicated that two dimensions of metacognition (positive and negative beliefs about worry) were significantly associated with anxiety and depression as predicted, providing further evidence of validity. Conclusions These findings provide initial evidence that the Metacognitions Questionnaire 30 is a valid measure for use in cancer populations

    Positronium oscillations to Mirror World revisited

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    We present a calculation of the branching ratio of orthopositronium decay into an invisible mode, which is done in the context of Mirror World models, where ordinary positronium can disappear from our world due to oscillation into its mirror twin. In this revision we clarify some formulas and approximations used previously, correct them at some places, add new effects relevant for a feasible experiment and finally perform a combined analysis. We include into consideration various effects due to external magnetic and electric fields, collisions with cavity walls and scattering off gas atoms in the cavity. Oscillations of the Rydberg positroniums are also considered. To perform a numerical estimates in a realistic case we wrote computer code, which can be adopted in any experimental setup. Its work is illustrated with an example of a planned positronium experiment within the AEgIS project.Comment: 23 pages, 4 figures, typos corrected, references added, published versio
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