987 resultados para SINGULAR RIEMANNIAN FOLIATIONS


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Esta Tesis presenta un nuevo método para filtrar errores en bases de datos multidimensionales. Este método no precisa ninguna información a priori sobre la naturaleza de los errores. En concreto, los errrores no deben ser necesariamente pequeños, ni de distribución aleatoria ni tener media cero. El único requerimiento es que no estén correlados con la información limpia propia de la base de datos. Este nuevo método se basa en una extensión mejorada del método básico de reconstrucción de huecos (capaz de reconstruir la información que falta de una base de datos multidimensional en posiciones conocidas) inventado por Everson y Sirovich (1995). El método de reconstrucción de huecos mejorado ha evolucionado como un método de filtrado de errores de dos pasos: en primer lugar, (a) identifica las posiciones en la base de datos afectadas por los errores y después, (b) reconstruye la información en dichas posiciones tratando la información de éstas como información desconocida. El método resultante filtra errores O(1) de forma eficiente, tanto si son errores aleatorios como sistemáticos e incluso si su distribución en la base de datos está concentrada o esparcida por ella. Primero, se ilustra el funcionamiento delmétodo con una base de datosmodelo bidimensional, que resulta de la dicretización de una función transcendental. Posteriormente, se presentan algunos casos prácticos de aplicación del método a dos bases de datos tridimensionales aerodinámicas que contienen la distribución de presiones sobre un ala a varios ángulos de ataque. Estas bases de datos resultan de modelos numéricos calculados en CFD. ABSTRACT A method is presented to filter errors out in multidimensional databases. The method does not require any a priori information about the nature the errors. In particular, the errors need not to be small, neither random, nor exhibit zero mean. Instead, they are only required to be relatively uncorrelated to the clean information contained in the database. The method is based on an improved extension of a seminal iterative gappy reconstruction method (able to reconstruct lost information at known positions in the database) due to Everson and Sirovich (1995). The improved gappy reconstruction method is evolved as an error filtering method in two steps, since it is adapted to first (a) identify the error locations in the database and then (b) reconstruct the information in these locations by treating the associated data as gappy data. The resultingmethod filters out O(1) errors in an efficient fashion, both when these are random and when they are systematic, and also both when they concentrated and when they are spread along the database. The performance of the method is first illustrated using a two-dimensional toymodel database resulting fromdiscretizing a transcendental function and then tested on two CFD-calculated, three-dimensional aerodynamic databases containing the pressure coefficient on the surface of a wing for varying values of the angle of attack. A more general performance analysis of the method is presented with the intention of quantifying the randomness factor the method admits maintaining a correct performance and secondly, quantifying the size of error the method can detect. Lastly, some improvements of the method are proposed with their respective verification.

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We describe the use of singular value decomposition in transforming genome-wide expression data from genes × arrays space to reduced diagonalized “eigengenes” × “eigenarrays” space, where the eigengenes (or eigenarrays) are unique orthonormal superpositions of the genes (or arrays). Normalizing the data by filtering out the eigengenes (and eigenarrays) that are inferred to represent noise or experimental artifacts enables meaningful comparison of the expression of different genes across different arrays in different experiments. Sorting the data according to the eigengenes and eigenarrays gives a global picture of the dynamics of gene expression, in which individual genes and arrays appear to be classified into groups of similar regulation and function, or similar cellular state and biological phenotype, respectively. After normalization and sorting, the significant eigengenes and eigenarrays can be associated with observed genome-wide effects of regulators, or with measured samples, in which these regulators are overactive or underactive, respectively.

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We give conditions that rule out formation of sharp fronts for certain two-dimensional incompressible flows. We show that a necessary condition of having a sharp front is that the flow has to have uncontrolled velocity growth. In the case of the quasi-geostrophic equation and two-dimensional Euler equation, we obtain estimates on the formation of semi-uniform fronts.

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The phase transition for turbulent diffusion, reported by Avellaneda and Majda [Avellaneda, M. & Majda, A. J. (1994) Philos. Trans. R. Soc. London A 346, 205-233, and several earlier papers], is traced to a modeling assumption in which the energy spectrum of the turbulent fluid is singularly dependent on the viscosity in the inertial range. Phenomenological models of turbulence and intermittency, by contrast, require that the energy spectrum be independent of the viscosity in the inertial range. When the energy spectrum is assumed to be consistent with the phenomenological models, there is no phase transition for turbulent diffusion.

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We prove global existence of nonnegative solutions to the one dimensional degenerate parabolic problems containing a singular term. We also show the global quenching phenomena for L1 initial datums. Moreover, the free boundary problem is considered in this paper.

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Perylene bisimides (PBIs) are n-type semiconducting and photogenerating materials widely used in a variety of optoelectronic devices. Particularly interesting are PBIs that are simultaneously water-soluble and liquid-crystalline (PBI-W+LC) and, thus, attractive for the development of high-performing easily processable applications in biology and “green” organic electronics. In this work, singular temperatures connected to charge transport mechanism transitions in a PBI-W+LC derivative are determined with high accuracy by means of temperature-dependent photocurrent studies. These singular temperatures include not only the ones observed at 60 and 110 °C, corresponding to phase transition temperatures from crystalline to liquid-crystalline (LC) and from LC to the isotropic phase, respectively, as confirmed by differential scanning calorimetry (DSC), but also a transition at 45 °C, not observed by DSC. By analyzing the photocurrent dependence simultaneously on temperature and on light intensity, this transition is interpreted as a change from monomolecular to bimolecular recombination. These results might be useful for other semiconducting photogenerating materials, not necessarily PBIs or even organic semiconductors, which also show transport behavior changes at singular temperatures not connected with structural or phase transitions.

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Aportación en el marco de las Jornadas Internacionales de Arquitectura y Urbanismo desde la perspectiva de las arquitectas, celebradas en la Escuela Técnica Superior de Arquitectura de Madrid en diciembre de 2008, sobre el papel desempeñado en la disciplina por las bienales de arquitectura y urbanismo, el papel de las mujeres en la arquitectura y el papel de las mujeres arquitectas en las bienales de arquitectura y urbanismo, en concreto, por Rosa Grena Kliass, Sofía von Ellrichshausen y la Casa Poli y Carme Pinós y la Torre Cube, todas ellas premiadas en estos certámenes.

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La Pharmacopea de la Armada, obra de Leandro de Vega, publicada en 1760 para uso de médicos y cirujanos de los buques y hospitales de la marina española a lo largo del siglo XVIII, está considerada como la primera farmacopea naval española. Su autor la define con un «catálogo de medicamentos pertenecientes a las enfermedades médicas», en definitiva un nomenclátor de fórmulas para la preparación de los medicamentos de mayor utilidad para los navegantes de la época, tanto de uso interno como externo. En el presente artículo se analiza en profundidad esta obra, reconocida su relevancia de fuente primaria, situándola en su contexto histórico, detallando el contenido de sus tratados, así como dando noticia biográfica de su autor e informando de la posición profesional y misión de sus destinatarios.

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The groundbreaking scope of the Economic Partnership Agreement (EPA) between the European Union (EU) and Cariforum (CF) irrefutably marks a substantive shift in trade relations between the regions and also has far-reaching implications across several sectors and levels. Supplementing the framework of analysis of Structural Foreign Policy (SFP) with neo-Gramscian theory allows for a thorough investigation into the details of structural embeddedness based on the EU's historic directionality towards the Caribbean region; notably, encouraging integration into the global capitalist economy by adapting to and adopting the ideals of neoliberal economics. Whilst the Caribbean – as the first and only signatory of a ‘full’ EPA – may be considered the case par excellence of the success of the EPAs, this paper demonstrates that there is no cause-effect relationship between the singular case of the ‘full’ CF-EU EPA and the success of the EPA policy towards the ACP in general. The research detailed throughout this paper responds to two SFP-based questions: (1) To what extent is the EPA a SFP tool aimed at influencing and shaping the structures in the Caribbean? (2) To what extent is the internalisation of this process reflective of the EU as a hegemonic SFP actor vis-à-vis the Caribbean? This paper affirms both the role of the EU as a hegemonic SFP actor and the EPA as a hegemonic SFP tool. Research into the negotiation, agreement and controversy that surrounds every stage of the EPA confirmed that through modern diplomacy and an evolution in relations, consensus is at the fore of contemporary EU-Caribbean relations. Whilst at once dealing with the singular case of the Caribbean, the author offers a nuanced approach beyond 'EU navel-gazing' by incorporating an ‘outside-in’ perspective, which thereafter could be applied to EU-ACP relations and the North-South dialogue in general.

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"A brief commentary on the Epistle": p. 28-42.

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"This work has been supported by the National Science Foundation under Grant G-1221"

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Mode of access: Internet.