38,569 research outputs found

    Flat Puppets on an Empty Screen, Stories in the Round Imagining Space in Wayang Kulit and the Worlds Beyond

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    The puppets are flat, the screen against which they are placed and moved is white and devoid of scenery. In what kinds of space do the stories of the classical shadow-play of Java, Bali, Lombok, and the Malay world unfold despite this double flatness? How do performers use not only puppets and screen but also music and language to bring space into being? What must spectators know and do to make sense of these storytelling techniques? As a contribution to the narratological study of the multimodal making of storyworlds, I demonstrate that wayang kulit caters for different degrees of interpretive competence, which yield different understandings of the space that wayang portrays. An expert way of apprehending space requires seeing beyond the screen, puppets, and silhouettes, or even looking away from them. At the same time the peculiar ways of narrating space in wayang point to a deeply felt spatiality in real-life contexts as well

    New Species and Additional Records of Protura from Michigan

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    Three new species, Eosentomon antrimense, E. pinusbanksianum, and Berberentulus mcqueeni, and one new record, E. australicum Womersley are added to the known Protura fauna of Michigan. Further records of E. wheeleri Silvestri, Protentomon michiganense Bernard, Proturentomon iowaense Womersley, Acerentulus confinis (Berlese) and Amerentulus amencanus (Ewing) are listed from various parts of the state

    Scalar Meson Spectroscopy with Lattice Staggered Fermions

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    With sufficiently light up and down quarks the isovector (a0a_0) and isosinglet (f0f_0) scalar meson propagators are dominated at large distance by two-meson states. In the staggered fermion formulation of lattice quantum chromodynamics, taste-symmetry breaking causes a proliferation of two-meson states that further complicates the analysis of these channels. Many of them are unphysical artifacts of the lattice approximation. They are expected to disappear in the continuum limit. The staggered-fermion fourth-root procedure has its purported counterpart in rooted staggered chiral perturbation theory (rSXPT). Fortunately, the rooted theory provides a strict framework that permits the analysis of scalar meson correlators in terms of only a small number of low energy couplings. Thus the analysis of the point-to-point scalar meson correlators in this context gives a useful consistency check of the fourth-root procedure and its proposed chiral realization. Through numerical simulation we have measured correlators for both the a0a_0 and f0f_0 channels in the ``Asqtad'' improved staggered fermion formulation in a lattice ensemble with lattice spacing a=0.12a = 0.12 fm. We analyze those correlators in the context of rSXPT and obtain values of the low energy chiral couplings that are reasonably consistent with previous determinations.Comment: 23 pp., 3 figs., submitted to Phys. Rev.

    Induced pseudoscalar form factor of the nucleon at two-loop order in chiral perturbation theory

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    We calculate the imaginary part of the induced pseudoscalar form factor of the nucleon GP(t)G_P(t) in the framework of two-loop heavy baryon chiral perturbation theory. The effect of the calculated three-pion continuum on the pseudoscalar constant gP=(mμ/2M)GP(t=0.877mμ2)g_P = (m_\mu/2M) G_P(t=-0.877m_\mu^2) measurable in ordinary muon capture μpνμn\mu^-p\to \nu_\mu n turns out to be negligibly small. Possible contributions from counterterms at two-loop order are numerically smaller than the uncertainty of the dominant pion-pole term proportional to the pion-nucleon coupling constant gπN=13.2±0.2g_{\pi N}= 13.2\pm 0.2. We conclude that a sufficiently accurate representation of the induced pseudoscalar form factor of the nucleon at low momentum transfers tt is given by the sum of the pion-pole term and the Adler-Dothan-Wolfenstein term: GP(t)=4gπNMfπ/(mπ2t)2gAM2/3G_P(t) = 4g_{\pi N} M f_\pi/ (m_\pi^2 -t)- 2g_A M^2 /3, with =(0.44±0.02) = (0.44 \pm 0.02) fm2^2 the axial mean square radius of the nucleon.Comment: 6 pages, 2 figures, accepted for publication in Physical Review

    Strong and Radiative Meson Decays in a Generalized Nambu--Jona-Lasinio Model

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    We investigate strong and radiative meson decays in a generalized Nambu--Jona-Lasinio model. The one loop order calculation provides a satisfactory agreement with the data for the mesonic spectrum and for radiative decays. Higher order effects for strong decays of ρ\rho and KK^* are estimated to be large. We also discuss the role of the flavour mixing determinantal interaction.Comment: 7 pages, LaTeX, 2 figs available upon request, CRN 92-4

    The Fubini-Furlan-Rossetti Sum Rule Revisited

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    The Fubini-Furlan-Rossetti sum rule for pion photoproduction on the nucleon is evaluated by dispersion relations at constant t, and the corrections to the sum rule due to the finite pion mass are calculated. Near threshold these corrections turn out to be large due to pion-loop effects, whereas the sum rule value is closely approached if the dispersion integrals are evaluated for sub-threshold kinematics. This extension to the unphysical region provides a unique framework to determine the low-energy constants of chiral perturbation theory by global properties of the excitation spectrum.Comment: 12 pages, 7 postscript figures, EPJ style files include

    Invariant Amplitudes for Pion Electroproduction

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    The invariant amplitudes for pion electroproduction on the nucleon are evaluated by dispersion relations at constant t with MAID as input for the imaginary parts of these amplitudes. In the threshold region these amplitudes are confronted with the predictions of several low-energy theorems derived in the soft-pion limit. In general agreement with Chiral Perturbation Theory, the dispersive approach yields large corrections to these theorems because of the finite pion mass.Comment: 18 pages, 8 figure
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