803 research outputs found

    Yoruba religious music

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    A Jesuit writer on mission theory wrote that he could not conceive how an African could worship God without dancing. We often hear nowadays of Mass chants being sung to the beating of tom-toms. To the surprise of European enthusiasts, African clergymen do not always react favourably to such developments. Can we dismiss such a reaction as due to inferiority complex? Or might it not be due to a misunderstanding about the true nature of African music? In a letter, S. M. Katana points out that Africans have a particular type of ceremonial music which expresses “feelings of worship” and he gives as an example the ceremonial music of the Buganda and Bunyoro

    Links between different analytic descriptions of constant mean curvature surfaces

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    Transformations between different analytic descriptions of constant mean curvature (CMC) surfaces are established. In particular, it is demonstrated that the system ψ1=(ψ12+ψ22)ψ2ˉψ2=(ψ12+ψ22)ψ1 \begin{split} &\partial \psi_{1} = (|\psi_{1}|^{2} + |\psi_{2}|^{2}) \psi_{2} \\ &\bar{\partial} \psi_{2} =- (|\psi_{1}|^{2} + |\psi_{2}|^{2}) \psi_{1} \end{split} descriptive of CMC surfaces within the framework of the generalized Weierstrass representation, decouples into a direct sum of the elliptic Sh-Gordon and Laplace equations. Connections of this system with the sigma model equations are established. It is pointed out, that the instanton solutions correspond to different Weierstrass parametrizations of the standard sphere S2E3S^{2} \subset E^{3}

    Self Interacting Dark Matter in the Solar System

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    Weakly coupled, almost massless, spin 0 particles have been predicted by many extensions of the standard model of particle physics. Recently, the PVLAS group observed a rotation of polarization of electromagnetic waves in vacuum in the presence of transverse magnetic field. This phenomenon is best explained by the existence of a weakly coupled light pseudoscalar particle. However, the coupling required by this experiment is much larger than the conventional astrophysical limits. Here we consider a hypothetical self-interacting pseudoscalar particle which couples weakly with visible matter. Assuming that these pseudoscalars pervade the galaxy, we show that the solar limits on the pseudoscalar-photon coupling can be evaded.Comment: 17 pages, 2 figure

    Mild place illusion: a virtual reality factor to spark creativity in writing

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    Developments in Virtual Reality (VR) technology have modified the creative potential of each individual. We introduce a new con cept, called "mild place illusion", as a new paradigm for designing VR-based user interfaces targeted at stimulating creativity. We show that for creative tasks - such as creative writing, new product ideation, and brainstorming - a "just-enough" amount of place illu sion leads to a greater self-perception of creativity, as opposed to a "full-level" place illusion. This is a somewhat unexpected result since one would suppose, a priori, to have the full-level place illu sion as the optimal setup for stimulating creativity. We considered that the methodology in this work was fairly complex, but our re sults show – through a data triangulation approach – that we were able to identify more consistent and personal creative experiences. Therefore, the main contribution of this paper is a new paradigm for designing VR user interfaces targeted at stimulating creativity by showing that a “one-illusion interspace” leads to a greater self perception of creativity.info:eu-repo/semantics/publishedVersio

    Sum Rule Description of Color Transparency

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    The assumption that a small point-like configuration does not interact with nucleons leads to a new set of sum rules that are interpreted as models of the baryon-nucleon interaction. These models are rendered semi-realistic by requiring consistency with data for cross section fluctuations in proton-proton diffractive collisions.Comment: 22 pages + 3 postscript figures attache

    The optical system of the H.E.S.S. imaging atmospheric Cherenkov telescopes, Part II: mirror alignment and point spread function

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    Mirror facets of the H.E.S.S. imaging atmospheric Cherenkov telescopes are aligned using stars imaged onto the closed lid of the PMT camera, viewed by a CCD camera. The alignment procedure works reliably and includes the automatic analysis of CCD images and control of the facet alignment actuators. On-axis, 80% of the reflected light is contained in a circle of less than 1 mrad diameter. The spot widens with increasing angle to the telescope axis. In accordance with simulations, the spot size has roughly doubled at an angle of 1.4 degr. from the axis. The expected variation of spot size with elevation due to deformations of the support structure is visible, but is completely non-critical over the usual working range. Overall, the optical quality of the telescope exceeds the specifications.Comment: 23 pages, 13 figure

    Orbital dependent nucleonic pairing in the lightest known isotopes of tin

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    By studying the 109Xe-->105Te-->101Sn superallowed alpha-decay chain, we observe low-lying states in 101Sn, the one-neutron system outside doubly magic 100Sn. We find that the spins of the ground state (J = 7=2) and first excited state (J = 5=2) in 101Sn are reversed with respect to the traditional level ordering postulated for 103Sn and the heavier tin isotopes. Through simple arguments and state-of-the-art shell model calculations we explain this unexpected switch in terms of a transition from the single-particle regime to the collective mode in which orbital-dependent pairing correlations, dominate.Comment: 5 pages 3 figure

    Exploring the vicinity of the Bogomol'nyi-Prasad-Sommerfield bound

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    We investigate systems of real scalar fields in bidimensional spacetime, dealing with potentials that are small modifications of potentials that admit supersymmetric extensions. The modifications are controlled by a real parameter, which allows implementing a perturbation procedure when such parameter is small. The approach allows obtaining the energy and topological charge in closed forms, up to first order in the parameter. We illustrate the procedure with some examples. In particular, we show how to remove the degeneracy in energy for the one-field and the two-field solutions that appear in a model of two real scalar fields.Comment: Revtex, 9 pages, To be published in J. Phys.

    Using eye-tracking in applied linguistics and second language research

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    With eye-tracking technology the eye is thought to give researchers a window into the mind. Importantly, eye-tracking has significant advantages over traditional online processing measures: chiefly that it allows for more ‘natural’ processing as it does not require a secondary task, and that it provides a very rich moment-to-moment data source. In recognition of the technology’s benefits, an ever increasing number of researchers in applied linguistics and second language research are beginning to use it. As eye-tracking gains traction in the field, it is important to ensure that it is established in an empirically sound fashion. To do this it is important for the field to come to an understanding about what eye-tracking is, what eye-tracking measures tell us, what it can be used for, and what different eye-tracking systems can and cannot do. Further, it is important to establish guidelines for designing sound research studies using the technology. The goal of the current review is to begin to address these issues

    On the equivalence principle and gravitational and inertial mass relation of classical charged particles

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    We show that the locally constant force necessary to get a stable hyperbolic motion regime for classical charged point particles, actually, is a combination of an applied external force and of the electromagnetic radiation reaction force. It implies, as the strong Equivalence Principle is valid, that the passive gravitational mass of a charged point particle should be slight greater than its inertial mass. An interesting new feature that emerges from the unexpected behavior of the gravitational and inertial mass relation, for classical charged particles, at very strong gravitational field, is the existence of a critical, particle dependent, gravitational field value that signs the validity domain of the strong Equivalence Principle. For electron and proton, these critical field values are gc4.8×1031m/s2g_{c}\simeq 4.8\times 10^{31}m/s^{2} and gc8.8×1034m/s2g_{c}\simeq 8.8\times 10^{34}m/s^{2}, respectively
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