2,734 research outputs found

    Translators, interpreters, and cultural negotiators : mediating and communicating power from the Middle Ages to the modern era.

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    This book reconsiders the intellectual, social and professional identity of translators and interpreters when their role involves an intercultural negotiation with institutional powers, be them medieval rulers, modern States, an army of invasion or a dominant culture. Surprisingly little is known of how historical mediations took place, how the mediators worked, and the ways in which transcultural mediations become implicit or explicit forms of power. The chapters seek to address how translators and interpreters can emerge in a position of power by presenting visions, methods, and case studies dealing with a wide thematic range of issues, such as historical concerns, cultural identity, and the role of translation in mediation and cultural transfer. With far-reaching analysis of history, politics, religion and literature, this book will appeal to researchers and students of translation, the history of communication, and institutional power

    Excised acoustic black holes: the scattering problem in the time domain

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    The scattering process of a dynamic perturbation impinging on a draining-tub model of an acoustic black hole is numerically solved in the time domain. Analogies with real black holes of General Relativity are explored by using recently developed mathematical tools involving finite elements methods, excision techniques, and constrained evolution schemes for strongly hyperbolic systems. In particular it is shown that superradiant scattering of a quasi-monochromatic wavepacket can produce strong amplification of the signal, offering the possibility of a significant extraction of rotational energy at suitable values of the angular frequency of the vortex and of the central frequency of the wavepacket. The results show that theoretical tools recently developed for gravitational waves can be brought to fruition in the study of other problems in which strong anisotropies are present.Comment: 8 pages, 9 figure

    A selfconsistent theory of current-induced switching of magnetization

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    A selfconsistent theory of the current-induced switching of magnetization using nonequilibrium Keldysh formalism is developed for a junction of two ferromagnets separated by a nonmagnetic spacer. It is shown that the spin-transfer torques responsible for current-induced switching of magnetization can be calculated from first principles in a steady state when the magnetization of the switching magnet is stationary. The spin-transfer torque is expressed in terms of one-electron surface Green functions for the junction cut into two independent parts by a cleavage plane immediately to the left and right of the switching magnet. The surface Green functions are calculated using a tight-binding Hamiltonian with parameters determined from a fit to an {\it ab initio} band structure.This treatment yields the spin transfer torques taking into account rigorously contributions from all the parts of the junction. To calculate the hysteresis loops of resistance versus current, and hence to determine the critical current for switching, the microscopically calculated spin-transfer torques are used as an input into the phenomenological Landau-Lifshitz equation with Gilbert damping. The present calculations for Co/Cu/Co(111) show that the critical current for switching is 107A/cm2\approx 10^7A/cm^2, which is in good agreement with experiment.Comment: 23 pages, 16 figure

    The Crossover beteween Aslamazov-Larkin and Short Wavelength Fluctuations Regimes in HTS Conductivity Experiments

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    We present paraconductivity (AL) measurements in three different high temperature superconductors: a melt textured YBa2Cu3O7YBa_2Cu_3O_7 sample, a Bi2Sr2CaCu2O8Bi_2Sr_2CaCu_2O_8 epitaxial thin film and a highly textured Bi2Sr2Ca2Cu3O10Bi_2Sr_2Ca_2Cu_3O_{10} tape. The crossovers between different temperature regimes in excess conductivity have been analysed. The Lawrence-Doniach (LD) crossover, which separates the 2D and 3D regimes, shifts from lower to higher temperatures as the compound anisotropy decreases. Once the LD crossover is overcome, the fluctuation conductivity of the three compounds shows the same universal behaviour: for ϵ=lnT/Tc>0.23\epsilon =\ln T/T_c > 0.23 all the curves bend down according to the 1/ϵ31/\epsilon^3 law. This asymptotic behaviour was theoretically predicted previously for the high temperature region where the short wavelength fluctuations (SWF) become important.Comment: 4 pages, Revtex, 1 PostScript figure available upon request ([email protected]); submitted to Physical Review B rapid communication

    Progetto Terra più Sicura: i rischi geologici e la loro prevenzione spiegati agli studenti delle scuole secondarie di primo grado

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    L'associazione Geologia Senza Frontiere onlus (www.gsf.it) è nata nel 2003 dalla volontà di un gruppo di geologi, ambientalisti e naturalisti di dare una prospettiva comune alle competenze conseguite nell'ambito della ricerca universitaria, dell'attività professionale e della cooperazione. Durante l'anno scolastico 2013-2014 Geologia Senza Frontiere ha ideato e realizzato il progetto Terra più Sicura (TpS), volto all'insegnamento dei rischi geologici in scuole secondarie di primo grado di Lazio, Toscana e Veneto. Gli obiettivi del progetto sono stati in particolare l'avvicinamento di studenti ed insegnanti ai problemi della sicurezza del territorio, dei rischi in esso presenti, oltre a come prevenire ed affrontare in maniera consapevole e corretta le emergenze naturali

    The Kinematics and Metallicity of the M31 Globular Cluster System

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    With the ultimate aim of distinguishing between various models describing the formation of galaxy halos (e.g. radial or multi-phase collapse, random mergers), we have completed a spectroscopic study of the globular cluster system of M31. We present the results of deep, intermediate-resolution, fibre-optic spectroscopy of several hundred of the M31 globular clusters using the Wide Field Fibre Optic Spectrograph (WYFFOS) at the William Herschel Telescope in La Palma, Canary Islands. These observations have yielded precise radial velocities (+/-12 km/s) and metallicities (+/-0.26 dex) for over 200 members of the M31 globular cluster population out to a radius of 1.5 degrees from the galaxy center. Many of these clusters have no previous published radial velocity or [Fe/H] estimates, and the remainder typically represent significant improvements over earlier determinations. We present analyses of the spatial, kinematic and metal abundance properties of the M31 globular clusters. We find that the abundance distribution of the cluster system is consistent with a bimodal distribution with peaks at [Fe/H] = -1.4 and -0.5. The metal-rich clusters demonstrate a centrally concentrated spatial distribution with a high rotation amplitude, although this population does not appear significantly flattened and is consistent with a bulge population. The metal-poor clusters tend to be less spatially concentrated and are also found to have a strong rotation signature.Comment: 33 pages, 20 figure

    Photoinduced time-resolved electrodynamics of superconducting metals and alloys

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    The photoexcited state in superconducting metals and alloys was studied via pump-probe spectroscopy. A pulsed Ti:sapphire laser was used to create the non-equilibrium state and the far-infrared pulses of a synchrotron storage ring, to which the laser is synchronized, measured the changes in the material optical properties. Both the time- and frequency- dependent photoinduced spectra of Pb, Nb, NbN, Nb{0.5}Ti{0.5}N, and Pb{0.75}Bi{0.25} superconducting thin films were measured in the low-fluence regime. The time dependent data establish the regions where the relaxation rate is dominated either by the phonon escape time (phonon bottleneck effect) or by the intrinsic quasiparticle recombination time. The photoinduced spectra measure directly the reduction of the superconducting gap due to an excess number of quasiparticles created by the short laser pulses. This gap shift allows us to establish the temperature range over which the low fluence approximation is valid.Comment: 12 pages with 10 figure

    Wide-Field Survey of Globular Clusters in M31. II. Kinematics of the Globular Cluster System

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    We present a kinematic analysis of the globular cluster(GC) system in M31. Using the photometric and spectroscopic database of 504 GCs, we have investigated the kinematics of the M31 GC system. We find that the all GC system shows strong rotation, with rotation amplitude of v_rot~190km/s, and that a weak rotation persists even for the outermost samples at |Y|>5kpc. The rotation-corrected velocity dispersion for the GC system is estimated to be sigma_{p,r}~130km/s, and it increases from sigma_{p,r}~120km/s at |Y|<1kpc to sigma_{p,r}~150km/s at |Y|>5kpc. These results are very similar to those for the metal-poor GCs. This shows that there is a dynamically hot halo in M31 that is rotating but primarily pressure-supported. We have identified 50 "friendless" GCs, and they appear to rotate around the major axis of M31. For the subsamples of metal-poor and metal-rich GCs, we have found that the metal-rich GCs are more centrally concentrated than the metal-poor GCs, and both subsamples show strong rotation. For the subsamples of bright and faint GCs, it is found that the rotation for the faint GCs is stronger than that for the bright GCs. We have identified 56 GCs and GC candidates with X-ray detection. It is found that the majority of X-ray emitting GCs follow the disk rotation, and that the redder, more metal-rich, and brighter GCs are more likely to be detected as X-ray emitting GCs. We have derived a rotation curve of M31 using the GCs at |Y|<0.6kpc. We have estimated the dynamical mass of M31 using `Projected Mass Estimator(PME)' and `Tracer Mass Estimator(TME)'. We finally discuss the implication of these results and compare the kinematics of GCs with that of planetary nebulae in M31.Comment: 62 pages, 26 figues, Accepted by Ap
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