System Design: UML Activity and Sequence Diagrams

In this session we look at how to model flow of control and interactions between components using UML Activity and Sequence Diagrams. This is an introductory session and so for Activity Diagrams we only cover branching, forks and joins and swim lanes, and for Sequence we cover lifelines, messages and returns, and alt, par and opt frames.

Caracterización de las variantes anatómicas de las venas pulmonares en pacientes candidatos a aislamiento de venas pulmonares en Colombia

Introducción y objetivos: El conocimiento de la anatomía de las venas pulmonares y de la aurícula izquierda es fundamental para la planeación y prevención de posibles complicaciones durante la ablación de las venas pulmonares, procedimiento realizado para el manejo de la fibrilación auricular. Este estudio pretende caracterizar la anatomía (tamaño y forma) de las venas pulmonares y determinar las variantes anatómicas más comunes de las mismas. Métodos: Se analizaron 277 estudios de angioresonancia tridimensional y tomografía computarizada realizados previo al procedimiento de aislamiento de venas pulmonares. Se evaluaron los diámetros de la aurícula izquierda, de los ostia de las venas pulmonares y se determinaron la presencia de venas pulmonares comunes, accesorias y ramificaciones tempranas. Resultados: 75% de nuestros pacientes presentaron la anatomía normal de dos venas pulmonares derechas y dos izquierdas. En un 10,1% de los casos se encontraron venas supernumerarias y en un 11,2% se encontró un tronco común. En un 61% de los pacientes se encontraron ramas ostiales, las cuales en un 39,4% de los casos se presentaron en la vena pulmonar inferior derecha. Conclusiones: La evaluación de la morfología de la aurícula derecha y las venas pulmonares por medio de angioresonancia o tomografía computarizada, es necesaria para la realización de ablación por radiofrecuencia dada la alta frecuencia de variantes anatómicas y presencia de ramas ostiales.

Random walk radiosity with generalized absorption probabilities

The author studies random walk estimators for radiosity with generalized absorption probabilities. That is, a path will either die or survive on a patch according to an arbitrary probability. The estimators studied so far, the infinite path length estimator and finite path length one, can be considered as particular cases. Practical applications of the random walks with generalized probabilities are given. A necessary and sufficient condition for the existence of the variance is given, together with heuristics to be used in practical cases. The optimal probabilities are also found for the case when one is interested in the whole scene, and are equal to the reflectivities

Anharmonicity contributions to the vibrational second hyperpolarizability of conjugated oligomers

Restricted Hartree-Fock 6-31G calculations of electrical and mechanical anharmonicity contributions to the longitudinal vibrational second hyperpolarizability have been carried out for eight homologous series of conjugated oligomers - polyacetylene, polyyne, polydiacetylene, polybutatriene, polycumulene, polysilane, polymethineimine, and polypyrrole. To draw conclusions about the limiting infinite polymer behavior, chains containing up to 12 heavy atoms along the conjugated backbone were considered. In general, the vibrational hyperpolarizabilities are substantial in comparison with their static electronic counterparts for the dc-Kerr and degenerate four-wave mixing processes (as well as for static fields) but not for electric field-induced second harmonic generation or third harmonic generation. Anharmonicity terms due to nuclear relaxation are important for the dc-Kerr effect (and for the static hyperpolarizability) in the σ-conjugated polymer, polysilane, as well as the nonplanar π systems polymethineimine and polypyrrole. Restricting polypyrrole to be planar, as it is in the crystal phase, causes these anharmonic terms to become negligible. When the same restriction is applied to polymethineimine the effect is reduced but remains quantitatively significant due to the first-order contribution. We conclude that anharmonicity associated with nuclear relaxation can be ignored, for semiquantitative purposes, in planar π-conjugated polymers. The role of zero-point vibrational averaging remains to be evaluated

Simple finite field method for calculation of static and dynamic vibrational hyperpolarizabilities: curvature contributions

In the static field limit, the vibrational hyperpolarizability consists of two contributions due to: (1) the shift in the equilibrium geometry (known as nuclear relaxation), and (2) the change in the shape of the potential energy surface (known as curvature). Simple finite field methods have previously been developed for evaluating these static field contributions and also for determining the effect of nuclear relaxation on dynamic vibrational hyperpolarizabilities in the infinite frequency approximation. In this paper the finite field approach is extended to include, within the infinite frequency approximation, the effect of curvature on the major dynamic nonlinear optical processes

Variational calculation of static and dynamic vibrational nonlinear optical properties

The vibrational configuration interaction method used to obtain static vibrational (hyper)polarizabilities is extended to dynamic nonlinear optical properties in the infinite optical frequency approximation. Illustrative calculations are carried out on H2 O and N H3. The former molecule is weakly anharmonic while the latter contains a strongly anharmonic umbrella mode. The effect on vibrational (hyper)polarizabilities due to various truncations of the potential energy and property surfaces involved in the calculation are examined

The curvature of the conical intersection seam: an approximate second-order analysis

We present a method for analyzing the curvature (second derivatives) of the conical intersection hyperline at an optimized critical point. Our method uses the projected Hessians of the degenerate states after elimination of the two branching space coordinates, and is equivalent to a frequency calculation on a single Born-Oppenheimer potential-energy surface. Based on the projected Hessians, we develop an equation for the energy as a function of a set of curvilinear coordinates where the degeneracy is preserved to second order (i.e., the conical intersection hyperline). The curvature of the potential-energy surface in these coordinates is the curvature of the conical intersection hyperline itself, and thus determines whether one has a minimum or saddle point on the hyperline. The equation used to classify optimized conical intersection points depends in a simple way on the first- and second-order degeneracy splittings calculated at these points. As an example, for fulvene, we show that the two optimized conical intersection points of C2v symmetry are saddle points on the intersection hyperline. Accordingly, there are further intersection points of lower energy, and one of C2 symmetry - presented here for the first time - is found to be the global minimum in the intersection space

Destierro y redención: el «síndrome de Adán y Eva» en La belleza del mundo de Héctor Tizón (Crítica)

En este ensayo, el autor plantea un diálogo entre la novela La belleza del mundo, de Héctor Tizón, y los arquetipos bíblicos de Adán y Eva, la pérdida del paraíso y el destierro, y el retorno al Edén. A partir de la traición primigenia de la esposa del protagonista, se inicia la integración a un tiempo cíclico e infinito –el del exilio. En el destierro, el protagonista está marcado por su afán de anular la temporalidad real y, a la vez, su propia identidad, intenta forzosamente olvidar la propia historia, lo cual lo conduce a una crisis de identidad. Al cabo de un largo recorrido, se plantea la necesidad de incorporar los acontecimientos de la vida a un tiempo mítico que regenere y perpetúe todas las acciones, y en el cual se busque el sufrimiento para alcanzar la salvación. El autor evidencia paralelismos diversos del texto con la doctrina cristiana: el protagonista comprende que para regresar a su propio centro debe perdonar. Y eso solo es posible regresando, enfrentando su pasado: el tiempo de redención es un regreso, pero el mismo-nuevo sitio no vuelve a ser jamás el paraíso.

Roberto Arlt, la nación y su angustiosa trayectoria (Dossier: Literaturas de la integración, el Sur y su diversidad)

En las primeras décadas del siglo XX, la Argentina sufrió un desajuste económico y social respecto del plan estratégico de 1880. Los acontecimientos históricos rompieron el modelo de la prosperidad infinita y pusieron de manifiesto la disolución del ser nacional en revueltas militares, fraude electoral, corrupción, caudillismo y brechas profundas entre regiones y clases sociales. Hacia 1930, la escritura de Roberto Artl se presenta como un cuestionamiento acerca de los límites del proyecto modernizador y de las instancias más significativas del mandato de progreso histórico. Los personajes de sus ficciones le permiten al escritor proyectar una interpretación no solo de su ser caído y angustiado, sino también del sujeto desligado de aquella sociabilidad propuesta por la generación de los románticos y que en 1880 parecía determinar una identidad estable, según reglas aparentemente seguras. El escritor posee la visión de que 1930 es el momento histórico que exige otro estatuto de lo real. El efecto de lectura de la obra de Arlt reside en la manipulación indefinida del lenguaje literario a través de la propuesta de personajes anclados en la percepción de un mundo que los excluye y de una peripecia narrativa que devela la descentración de la Historia como relato total. Consecuentemente, su eficacia es impactar y movilizar el cuerpo social a través de la producción imaginaria como una versión literaria de la Historia.

Cual los imbéciles, buscando un bastón (En torno al enmarañado viaje de Henri Michaux al Ecuador)[Estudio]

En Ecuador. Journal de Voyage (1929) Henri Michaux quisiera ir más allá del vértigo del vacío y de la nada, dar con los significados que se le escapan, dar quizás con lo “transreal”. Con esa lente, y teniendo en cuenta el contexto histórico e ideológico, hay que entrar en la relación del autor belga-francés a lo largo del Atlántico, por la región andina ecuatoriana, y por la Amazonía. Por eso vale ilustrar, aunque sea tangencialmente, la práctica literaria que caracteriza esa obra para no hacer de ella un mero reportaje de viaje cuando, en efecto, se trata de un libro de exigente lectura, de un esfuerzo, por no decir de un tratado, de inspiración poética, teórica, que responde a una estética y a un diseño, a una estilizada y hasta sistemática cosmovisión. Las analogías y yuxtaposiciones de inspiración vanguardista entregan un mundo en que coinciden, estallan y contrastan lo exterior y lo interior, lo dinámico y lo estático, lo cotidiano y lo extraño, lo íntimo y lo vasto, lo sagrado y lo profano, lo limitado y lo infinito. Palabras clave: Henri Michaux, viaje, búsqueda, historia, Ecuador/ecuador, Europa, Atlántico, Andes, Amazonía, yuxtaposición, contraste, analogías, espacio, viviendas rústicas, música, remedos, límites, borroso, infinito.

On the convergence of the no response test

The no response test is a new scheme in inverse problems for partial differential equations which was recently proposed in [D. R. Luke and R. Potthast, SIAM J. Appl. Math., 63 (2003), pp. 1292–1312] in the framework of inverse acoustic scattering problems. The main idea of the scheme is to construct special probing waves which are small on some test domain. Then the response for these waves is constructed. If the response is small, the unknown object is assumed to be a subset of the test domain. The response is constructed from one, several, or many particular solutions of the problem under consideration. In this paper, we investigate the convergence of the no response test for the reconstruction information about inclusions D from the Cauchy values of solutions to the Helmholtz equation on an outer surface $\partial\Omega$ with $\overline{D} \subset \Omega$. We show that the one‐wave no response test provides a criterion to test the analytic extensibility of a field. In particular, we investigate the construction of approximations for the set of singular points $N(u)$ of the total fields u from one given pair of Cauchy data. Thus, the no response test solves a particular version of the classical Cauchy problem. Also, if an infinite number of fields is given, we prove that a multifield version of the no response test reconstructs the unknown inclusion D. This is the first convergence analysis which could be achieved for the no response test.

Fusion of motion segmentation algorithms

Many algorithms have been developed to achieve motion segmentation for video surveillance. The algorithms produce varying performances under the infinite amount of changing conditions. It has been recognised that individually these algorithms have useful properties. Fusing the statistical result of these algorithms is investigated, with robust motion segmentation in mind.

Selection-mutation balance models with epistatic selection

We present an application of birth-and-death processes on configuration spaces to a generalized mutation4 selection balance model. The model describes the aging of population as a process of accumulation of mu5 tations in a genotype. A rigorous treatment demands that mutations correspond to points in abstract spaces. 6 Our model describes an infinite-population, infinite-sites model in continuum. The dynamical equation which 7 describes the system, is of Kimura-Maruyama type. The problem can be posed in terms of evolution of states 8 (differential equation) or, equivalently, represented in terms of Feynman-Kac formula. The questions of interest 9 are the existence of a solution, its asymptotic behavior, and properties of the limiting state. In the non-epistatic 10 case the problem was posed and solved in [Steinsaltz D., Evans S.N., Wachter K.W., Adv. Appl. Math., 2005, 11 35(1)]. In our model we consider a topological space X as the space of positions of mutations and the influence of epistatic potentials

Microscopic Mechanisms of Strain Hardening in Glassy Polymers

The mechanisms underlying the increase in stress for large mechanical strains of a polymer glass, quantified by the strain-hardening modulus, are still poorly understood. In the present paper we aim to elucidate this matter and present new mechanisms. Molecular-dynamics simulations of two polymers with very different strain-hardening moduli (polycarbonate and polystyrene) have been carried out. Nonaffine displacements occur because of steric hindrances and connectivity constraints. We argue that it is not necessary to introduce the concept of entanglements to understand strain hardening, but that hardening is rather coupled with the increase in the rate of nonaffine particle displacements. This rate increases faster for polycarbonate, which has the higher strain-hardening modulus. Also more nonaffine chain stretching is present for polycarbonate. It is shown that the inner distances of such a nonaffinely deformed chain can be well described by the inner distances of the worm-like chain, but with an effective stiffness length (equal to the Kuhn length for an infinite worm-like chain) that increases during deformation. It originates from the finite extensibility of the chain. In this way the increase in nonaffine particle displacement can be understood as resulting from an increase in the effective stiffness length of the perturbed chain during deformation, so that at larger strains a higher rate of plastic events in terms of nonaffine displacement is necessary, causing in turn the observed strain hardening in polymer glasses.