3,977 research outputs found

    Hans Staden's captive soul: Identity, imperialism, and rumors of cannibalism in sixteenth-century Brazil

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    This article examines the ways sixteenth-century reports of cultural cannibalism among the Tupinamba of Brazil were employed strategically by Europeans and Brazilians in the contest for economic, spiritual, and cultural dominance in the Atlantic world. By focusing on the experience of captivity among the Tupinamba by Hans Staden of Germany, this essay also explores the use of the cannibal by one ordinary man, as he negotiated dangerous limitations on identity and free will in the context of Reformation and imperial battles to possess both bodies and souls

    Dynamics of a hyperbolic system that applies at the onset of the oscillatory instability

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    A real hyperbolic system is considered that applies near the onset of the oscillatory instability in large spatial domains. The validity of that system requires that some intermediate scales (large compared with the basic wavelength of the unstable modes but small compared with the size of the system) remain inhibited; that condition is analysed in some detail. The dynamics associated with the hyperbolic system is fully analysed to conclude that it is very simple if the coefficient of the cross-nonlinearity is such that , while the system exhibits increasing complexity (including period-doubling sequences, quasiperiodic transitions, crises) as the bifurcation parameter grows if ; if then the system behaves subcritically. Our results are seen to compare well, both qualitatively and quantitatively, with the experimentally obtained ones for the oscillatory instability of straight rolls in pure Rayleigh - Bénard convection

    Martel in the Slovene Karst in 1893

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    E.A. Martel (1859-1938) is rightly regarded as one of the most important people in the history of cave study. Writing in French, as he did, his work was little known in those parts of central Europe that were in the Austrian empire. Thus much of what he wrote about the Classical Karst was not readily accessible to those now living in that area. It is for that reason that this English translation of his 1894 publication has been made. Martel had been in Slovenia from 14 September 1893 to mid October. He was shown the principal caves and karst features of the region by Wilhelm Putick who had been exploring these places from 1886 onwards. This assistance had been authorised by Count Falkenhayn, the Minister of Agriculture in Wien. Such was the importance with which Martel was regarded internationally

    Asymptotic stability of solitons for the Benjamin-Ono equation

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    In this paper, we prove the asymptotic stability of the family of solitons of the Benjamin-Ono equation in the energy space. The proof is based on a Liouville property for solutions close to the solitons for this equation, in the spirit of Martel and Merle (arXiv:0706.1174v2). As a corollary of the proofs, we obtain the asymptotic stability of exact multi-solitons.Comment: Submitted for publication on December 26, 200

    GePEToS : A Geant4 Monte Carlo simulation package for Positron Emission Tomography

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    GePEToS is a simulation framework developed over the last few years for assessing the instrumental performance of future PET scanners. It is based on Geant4, written in Object-Oriented C++ and runs on Linux platforms. The validity of GePEToS has been tested on the well-known Siemens ECAT EXACT HR+ camera. The results of two application examples are presented : the design optimization of a liquid Xe micro-PET camera dedicated to small animal imaging as well as the evaluation of the effect of a strong axial magnetic field on the image resolution of a Concorde P4 micro-PET camera.Comment: 5 pages, 12 figures, submitted to IEEE Transactions on Nuclear Scienc

    Gravitational waveforms from a point particle orbiting a Schwarzschild black hole

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    We numerically solve the inhomogeneous Zerilli-Moncrief and Regge-Wheeler equations in the time domain. We obtain the gravitational waveforms produced by a point-particle of mass μ\mu traveling around a Schwarzschild black hole of mass M on arbitrary bound and unbound orbits. Fluxes of energy and angular momentum at infinity and the event horizon are also calculated. Results for circular orbits, selected cases of eccentric orbits, and parabolic orbits are presented. The numerical results from the time-domain code indicate that, for all three types of orbital motion, black hole absorption contributes less than 1% of the total flux, so long as the orbital radius r_p(t) satisfies r_p(t)> 5M at all times.Comment: revtex4, 24 pages, 23 figures, 3 tables, submitted to PR

    Finite size effects near the onset of the oscillatory instability

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    A system of two complex Ginzburg - Landau equations is considered that applies at the onset of the oscillatory instability in spatial domains whose size is large (but finite) in one direction; the dependent variables are the slowly modulated complex amplitudes of two counterpropagating wavetrains. In order to obtain a well posed problem, four boundary conditions must be imposed at the boundaries. Two of them were already known, and the other two are first derived in this paper. In the generic case when the group velocity is of order unity, the resulting problem has terms that are not of the same order of magnitude. This fact allows us to consider two distinguished limits and to derive two associated (simpler) sub-models, that are briefly discussed. Our results predict quite a rich variety of complex dynamics that is due to both the modulational instability and finite size effects
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