8 resultados para Lie
em Archivo Digital para la Docencia y la Investigación - Repositorio Institucional de la Universidad del País Vasco
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Eterio Pajares, Raquel Merino y José Miguel Santamaría (eds.)
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[ES] Este trabajo propone una lectura de los seis primeros cuadernos del diario que Alejandra Pizarnik escribió a lo largo de toda su vida, desde los 18 años y hasta que murió a la edad de 36. El análisis de estos cuadernos, escritos entre 1954 y 1958, nos permite recorrer el itinerario que Alejandra Pizarnik realiza por la cuestión genérica, la cuestión nacional y la cuestión sexual. Desde su experiencia en cuanto sujeto, la escritura registra esta primera fase en la construcción del yo que Pizarnik desea para su diario. Esta fase, que se puede denominar etapa-derribo, está dominada por el desafío a las ideas del discurso hegemónico. Una vez haya resuelto este escollo en la construcción del yo de su diario, la escritura de Pizarnik no volverá sobre estos temas. Sin embargo, la búsqueda el “verdadero” yo se registra como proceso en el que a un movimiento de construcción del yo, le sigue un movimiento de destrucción de lo que las palabras han conformado, en secuencias en las que la apelación a la mentira de lo escrito o la desconfi anza en la capacidad del lenguaje para expresarlo, son la pauta de dicha escritura.
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[EN] Progress in methodology in specific fields is usually very closely linked to the technological progress in other areas of knowledge. This justifies the fact that lexicographical techniques have had to wait for the arrival of the IT era of the last decades of the 20th century in order to be able to create specialised electronic dictionaries which can house and systemise enormous amounts of information which can later be dealt with quickly and efficiently. This study proposes a practical-methodological model which aims to solve the grammatical treatment of adverbs in Ancient Latin. We have suggested a list of 5 types, in a decreasing order from a greater to lesser degree of specialisation; technical (T), semi-technical (S-T), instrumental-valued (I-V), instrumental- descriptive (I-D), instrumental-expository (I-E).
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The aim of this paper is to propose a new solution for the roommate problem with strict preferences. We introduce the solution of maximum irreversibility and consider almost stable matchings (Abraham et al. [2])and maximum stable matchings (Ta [30] [32]). We find that almost stable matchings are incompatible with the other two solutions. Hence, to solve the roommate problem we propose matchings that lie at the intersection of the maximum irreversible matchings and maximum stable matchings, which are called Q-stable matchings. These matchings are core consistent and we offer an effi cient algorithm for computing one of them. The outcome of the algorithm belongs to an absorbing set.
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Hydrogen is the only atom for which the Schr odinger equation is solvable. Consisting only of a proton and an electron, hydrogen is the lightest element and, nevertheless, is far from being simple. Under ambient conditions, it forms diatomic molecules H2 in gas phase, but di erent temperature and pressures lead to a complex phase diagram, which is not completely known yet. Solid hydrogen was rst documented in 1899 [1] and was found to be isolating. At higher pressures, however, hydrogen can be metallized. In 1935 Wigner and Huntington predicted that the metallization pressure would be 25 GPa [2], where molecules would disociate to form a monoatomic metal, as alkali metals that lie below hydrogen in the periodic table. The prediction of the metallization pressure turned out to be wrong: metallic hydrogen has not been found yet, even under a pressure as high as 320 GPa. Nevertheless, extrapolations based on optical measurements suggest that a metallic phase may be attained at 450 GPa [3]. The interest of material scientist in metallic hydrogen can be attributed, at least to a great extent, to Ashcroft, who in 1968 suggested that such a system could be a hightemperature superconductor [4]. The temperature at which this material would exhibit a transition from a superconducting to a non-superconducting state (Tc) was estimated to be around room temperature. The implications of such a statement are very interesting in the eld of astrophysics: in planets that contain a big quantity of hydrogen and whose temperature is below Tc, superconducting hydrogen may be found, specially at the center, where the gravitational pressure is high. This might be the case of Jupiter, whose proportion of hydrogen is about 90%. There are also speculations suggesting that the high magnetic eld of Jupiter is due to persistent currents related to the superconducting phase [5]. Metallization and superconductivity of hydrogen has puzzled scientists for decades, and the community is trying to answer several questions. For instance, what is the structure of hydrogen at very high pressures? Or a more general one: what is the maximum Tc a phonon-mediated superconductor can have [6]? A great experimental e ort has been carried out pursuing metallic hydrogen and trying to answer the questions above; however, the characterization of solid phases of hydrogen is a hard task. Achieving the high pressures needed to get the sought phases requires advanced technologies. Diamond anvil cells (DAC) are commonly used devices. These devices consist of two diamonds with a tip of small area; for this reason, when a force is applied, the pressure exerted is very big. This pressure is uniaxial, but it can be turned into hydrostatic pressure using transmitting media. Nowadays, this method makes it possible to reach pressures higher than 300 GPa, but even at this pressure hydrogen does not show metallic properties. A recently developed technique that is an improvement of DAC can reach pressures as high as 600 GPa [7], so it is a promising step forward in high pressure physics. Another drawback is that the electronic density of the structures is so low that X-ray di raction patterns have low resolution. For these reasons, ab initio studies are an important source of knowledge in this eld, within their limitations. When treating hydrogen, there are many subtleties in the calculations: as the atoms are so light, the ions forming the crystalline lattice have signi cant displacements even when temperatures are very low, and even at T=0 K, due to Heisenberg's uncertainty principle. Thus, the energy corresponding to this zero-point (ZP) motion is signi cant and has to be included in an accurate determination of the most stable phase. This has been done including ZP vibrational energies within the harmonic approximation for a range of pressures and at T=0 K, giving rise to a series of structures that are stable in their respective pressure ranges [8]. Very recently, a treatment of the phases of hydrogen that includes anharmonicity in ZP energies has suggested that relative stability of the phases may change with respect to the calculations within the harmonic approximation [9]. Many of the proposed structures for solid hydrogen have been investigated. Particularly, the Cmca-4 structure, which was found to be the stable one from 385-490 GPa [8], is metallic. Calculations for this structure, within the harmonic approximation for the ionic motion, predict a Tc up to 242 K at 450 GPa [10]. Nonetheless, due to the big ionic displacements, the harmonic approximation may not su ce to describe correctly the system. The aim of this work is to apply a recently developed method to treat anharmonicity, the stochastic self-consistent harmonic approximation (SSCHA) [11], to Cmca-4 metallic hydrogen. This way, we will be able to study the e ects of anharmonicity in the phonon spectrum and to try to understand the changes it may provoque in the value of Tc. The work is structured as follows. First we present the theoretical basis of the calculations: Density Functional Theory (DFT) for the electronic calculations, phonons in the harmonic approximation and the SSCHA. Then we apply these methods to Cmca-4 hydrogen and we discuss the results obtained. In the last chapter we draw some conclusions and propose possible future work.
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Cap. 1. Museos y patrimonio: de la distancia retórica a la interlocución democrática. Iñaki Díaz Balerdi. Cap. 2. Au coeur des conflits entre memoire, histoire et developpement economique, les nouveaux enjeux des musees de société aujourd’hui. François Hubert. Cap. 3. Elites, Instituciones Públicas, identidad cultural y turismo en los orígenes del Museo Municipal de Donostia-San Sebastián. Iñaki Arrieta Urtizberea. Cap. 4. Los orígenes de la museografía etnográfica en Cataluña: el Arxiu-Museu Folklòric de Ripoll. Oriol Beltran Costa. Cap. 5. Museo de la Pesca en Palamós: espacio para la memoria de los pescadores. Miquel Martí i Llambrich. Cap. 6. Arqueología y museos en Gipuzkoa; las experiencias del Centro de Estudios ARKEOLAN (1986-2005). Mª Mercedes Urteaga Artigas. Cap. 7. Penser un Musée des Confluences: un autre discours sur soi et les autres que soi. Thierry Valentin. Cap. 8. Turismo cultural y museos: oportunidades de desarrollo comunes. El caso de Cesis, Letonia. María Fernández Sabau. Cap. 9. La gestión y el uso turístico de los museos: la experiencia de Barcelona. Jordi Juan Tresserras y Juan Carlos Matamala. Cap. 10. Museos, turismo y desarrollo local en el norte de Portugal: el Ecomuseo del Barroso. Xerardo Pereiro. Cap. 11. Turismo y patrimonio cultural en las pequeñas y medianas ciudades: el Barri Vell de Girona y el Museu d’Art de Girona. Josep Manuel Rueda Torres.
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This paper investigates some properties of cyclic fuzzy maps in metric spaces. The convergence of distances as well as that of sequences being generated as iterates defined by a class of contractive cyclic fuzzy mapping to fuzzy best proximity points of (non-necessarily intersecting adjacent subsets) of the cyclic disposal is studied. An extension is given for the case when the images of the points of a class of contractive cyclic fuzzy mappings restricted to a particular subset of the cyclic disposal are allowed to lie either in the same subset or in its next adjacent one.
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Master in Literature and Literary Science