La cooperación internacional para el desarrollo

La Cooperación Internacional para el desarrollo se ha caracterizado por una evolución constante a lo largo de las últimas tres décadas. Las bases sobre las cuales se han practicado dicha cooperación han sido reformuladas, impactando la forma en que los diversos agentes involucrados interactúan. En la primera parte de éste trabajo se busca caracterizar la naturaleza de la interacción entre agentes dentro del proceso de cooperación; para ello recurrimos a la Teoría de Juegos, en particular a los Juegos Cooperativos en su modalidad de Acuerdo; introduciendo el concepto de óptimo de Pareto y el postulado de eficiencia de Coase. La segunda parte de éste trabajo es dedicada al concepto de Desarrollo. Describimos su evolución -caracterizada por la ruptura de paradigmas-; exponemos dos enfoques: uno basado en el cómo y para quién y otro temporario que hace referencia al corto y largo plazo; resaltando que el enfoque actual es aquel centrado en los elementos humanos. Por otra parte, analizamos el rol que tiene la Ayuda Oficial al Desarrollo (AOD), desde un punto de vista político, permitiéndonos entrever los intereses implícitos de la misma en los Estados receptores. Finalmente, describimos los elementos críticos de la evolución de las relaciones y la cooperación para el desarrollo entre América latina y la Unión Europea, así como la relación de Colombia con ésta última. Adicionalmente, detallamos el importante rol que las Organizaciones No Gubernamentales (ONG) han tenido para el desarrollo de los proyectos generados dentro del marco de las relaciones de cooperación entre América Latina y la Unión Europea.

Asymmetries in Business Cycles

Esta disertación busca estudiar los mecanismos de transmisión que vinculan el comportamiento de agentes y firmas con las asimetrías presentes en los ciclos económicos. Para lograr esto, se construyeron tres modelos DSGE. El en primer capítulo, el supuesto de función cuadrática simétrica de ajuste de la inversión fue removido, y el modelo canónico RBC fue reformulado suponiendo que des-invertir es más costoso que invertir una unidad de capital físico. En el segundo capítulo, la contribución más importante de esta disertación es presentada: la construcción de una función de utilidad general que anida aversión a la pérdida, aversión al riesgo y formación de hábitos, por medio de una función de transición suave. La razón para hacerlo así es el hecho de que los individuos son aversos a la pérdidad en recesiones, y son aversos al riesgo en auges. En el tercer capítulo, las asimetrías en los ciclos económicos son analizadas junto con ajuste asimétrico en precios y salarios en un contexto neokeynesiano, con el fin de encontrar una explicación teórica de la bien documentada asimetría presente en la Curva de Phillips.

Business cycle asymmetries: Loss aversion, sticky prices, and wages

In this chapter, the Smets-Wouters (2003) New Kenesian model is reformulated by introducing the loss aversion utility function developed in chapter two. The purpose of this is to understand how asymmetric real business cycles are linked to asymmetric behavior of agents in a price and wage rigidities set up. The simulations of the model reveal not only that the loss aversion in consumption and leisure is a good mechanism channel for explaining business cycle asymmetries, but also is a good mechanism channel for explaining asymmetric adjustment of prices and wages. Therefore the existence of asymmetries in Phillips Curve. Moreover, loss aversion makes downward rigidities in prices and wages stronger and also reproduces a more severe and persistent fall of the employment. All in all, this model generates asymmetrical real business cycles, asymmetric price and wage adjustment as well as hysteresis.

Selected configuration interaction with truncation energy error and application to the Ne atom

Selected configuration interaction (SCI) for atomic and molecular electronic structure calculations is reformulated in a general framework encompassing all CI methods. The linked cluster expansion is used as an intermediate device to approximate CI coefficients BK of disconnected configurations (those that can be expressed as products of combinations of singly and doubly excited ones) in terms of CI coefficients of lower-excited configurations where each K is a linear combination of configuration-state-functions (CSFs) over all degenerate elements of K. Disconnected configurations up to sextuply excited ones are selected by Brown's energy formula, ΔEK=(E-HKK)BK2/(1-BK2), with BK determined from coefficients of singly and doubly excited configurations. The truncation energy error from disconnected configurations, Δdis, is approximated by the sum of ΔEKS of all discarded Ks. The remaining (connected) configurations are selected by thresholds based on natural orbital concepts. Given a model CI space M, a usual upper bound ES is computed by CI in a selected space S, and EM=E S+ΔEdis+δE, where δE is a residual error which can be calculated by well-defined sensitivity analyses. An SCI calculation on Ne ground state featuring 1077 orbitals is presented. Convergence to within near spectroscopic accuracy (0.5 cm-1) is achieved in a model space M of 1.4× 109 CSFs (1.1 × 1012 determinants) containing up to quadruply excited CSFs. Accurate energy contributions of quintuples and sextuples in a model space of 6.5 × 1012 CSFs are obtained. The impact of SCI on various orbital methods is discussed. Since ΔEdis can readily be calculated for very large basis sets without the need of a CI calculation, it can be used to estimate the orbital basis incompleteness error. A method for precise and efficient evaluation of ES is taken up in a companion paper

O papel da liderança na promoção de uma dinâmica de escola aprendente- um projeto em desenvolvimento

A época atual exige que a escola se reformule e se adapte às exigências locais, nacionais e mundiais com as quais se confronta. O professor, ator principal das mudanças requeridas, vê aumentar significativamente as suas funções, necessitando de uma formação que corresponda às suas necessidades e que terá de efetivar ao longo de toda a sua vida profissional. Contudo, a formação proposta pelos centros de formação nem sempre se afigura a mais adequada. Para mudar, a escola precisa de lideranças fortes que apostem numa formação que vá ao encontro das necessidades sentidas e tente dar respostas eficazes. Tendo por base estes pressupostos, o presente projeto pretende investigar, no contexto particular de uma determinada escola, o modo como a(s) lideranças promovem uma dinâmica de escola aprendente e dinamizam formações que correspondam às necessidades sentidas. Este estudo permite-nos concluir que a(s) liderança(s) é um dos fatores que influencia fortemente o plano de formação, muito embora não seja o único. O entendimento que a(s) lideranças têm da formação, do desenvolvimento profissional e do futuro da escola, condiciona fortemente a dinâmica de escola que aprende. Decorrente da visão sobre a formação na escola alvo deste estudo, construiu-se um plano de ação de formação que assenta na criação de uma equipa de formação, team-teaching, centrada na escola, trabalhando colaborativamente, para dar início ao que poderá ser a solução para o problema identificado: uma formação que responda efetivamente e eficazmente às necessidades de formação dos professores da escola para fazer face às exigências da escola atual. Assim, partindo do team-teaching no departamento de línguas, tentar-se-á alargar a experiência e criar as bases para uma formação que promova a dinâmica de escola aprendente.

Honorarios [adaptaciones y refundiciones en De la Cuadra y Aguilera-Malta] (Dossier: Cuatro narradores del 30, relecturas en su centenario)

Se contrasta Honorarios, obra dramática de Aguilera-Malta, y «Honorarios», el cuento de José de la Cuadra que la inspiró. El diálogo entre los dos autores fue explícito en diversos textos, así como en sus respectivos mundos literarios: nombres de personajes, motivos, leyendas, mitos, formas, ideología y demandas, actitudes e intereses. De la Cuadra dialogó a su vez con otros creadores. «Honorarios», e.g., recrea y reinterpreta la figura del mítico fetiche Moloch, según lo representan Metrópolis, del cineasta Fritz Lang, y Salambó, de Gustave Flaubert, la narración aludida es también una refundición en torno al tema del poder omnipresente y cruel, que requiere insaciablemente de víctimas propiciatorias. De igual manera, en su proceso creativo y de búsqueda expresiva, Aguilera-Malta acostumbró remozar y reformular temas en diferentes géneros literarios –como el de la lucha del ser humano frente a las fuerzas hostiles de la naturaleza y la sociedad, interpretado en La isla virgen, El tigre y Jaguar–. En Honorarios, Aguilera-Malta se concentró en hallar la manera de transferir la trama del relato «Honorarios» al género dramático. El resultado es una eficaz refundición, en términos de la perspectiva histórico-política y de reflexiones sobre la función de la literatura.

Boundary integral equations on unbounded rough surfaces: Fredholmness and the finite section method

We consider a class of boundary integral equations that arise in the study of strongly elliptic BVPs in unbounded domains of the form $D = \{(x, z)\in \mathbb{R}^{n+1} : x\in \mathbb{R}^n, z > f(x)\}$ where $f : \mathbb{R}^n \to\mathbb{R}$ is a sufficiently smooth bounded and continuous function. A number of specific problems of this type, for example acoustic scattering problems, problems involving elastic waves, and problems in potential theory, have been reformulated as second kind integral equations $u+Ku = v$ in the space $BC$ of bounded, continuous functions. Having recourse to the so-called limit operator method, we address two questions for the operator $A = I + K$ under consideration, with an emphasis on the function space setting $BC$. Firstly, under which conditions is $A$ a Fredholm operator, and, secondly, when is the finite section method applicable to $A$?

Projected gradient approach to the numerical solution of the SCoTLASS

The SCoTLASS problem-principal component analysis modified so that the components satisfy the Least Absolute Shrinkage and Selection Operator (LASSO) constraint-is reformulated as a dynamical system on the unit sphere. The LASSO inequality constraint is tackled by exterior penalty function. A globally convergent algorithm is developed based on the projected gradient approach. The algorithm is illustrated numerically and discussed on a well-known data set. (c) 2004 Elsevier B.V. All rights reserved.

Estimation of the friction velocity in stably stratified boundary-layer flows over hills

A method is suggested for the calculation of the friction velocity for stable turbulent boundary-layer flow over hills. The method is tested using a continuous upstream mean velocity profile compatible with the propagation of gravity waves, and is incorporated into the linear model of Hunt, Leibovich and Richards with the modification proposed by Hunt, Richards and Brighton to include the effects of stability, and the reformulated solution of Weng for the near-surface region. Those theoretical results are compared with results from simulations using a non-hydrostatic microscale-mesoscale two-dimensional numerical model, and with field observations for different values of stability. These comparisons show a considerable improvement in the behaviour of the theoretical model when the friction velocity is calculated using the method proposed here, leading to a consistent variation of the boundary-layer structure with stability, and better agreement with observational and numerical data.

The (de)merits of minimum-variance hedging: application to the crack spread

We study the empirical performance of the classical minimum-variance hedging strategy, comparing several econometric models for estimating hedge ratios of crude oil, gasoline and heating oil crack spreads. Given the great variability and large jumps in both spot and futures prices, considerable care is required when processing the relevant data and accounting for the costs of maintaining and re-balancing the hedge position. We find that the variance reduction produced by all models is statistically and economically indistinguishable from the one-for-one “naïve” hedge. However, minimum-variance hedging models, especially those based on GARCH, generate much greater margin and transaction costs than the naïve hedge. Therefore we encourage hedgers to use a naïve hedging strategy on the crack spread bundles now offered by the exchange; this strategy is the cheapest and easiest to implement. Our conclusion contradicts the majority of the existing literature, which favours the implementation of GARCH-based hedging strategies.

Noise propagation from a cutting of arbitrary cross-section and impedance

A boundary integral equation is described for the prediction of acoustic propagation from a monofrequency coherent line source in a cutting with impedance boundary conditions onto surrounding flat impedance ground. The problem is stated as a boundary value problem for the Helmholtz equation and is subsequently reformulated as a system of boundary integral equations via Green's theorem. It is shown that the integral equation formulation has a unique solution at all wavenumbers. The numerical solution of the coupled boundary integral equations by a simple boundary element method is then described. The convergence of the numerical scheme is demonstrated experimentally. Predictions of A-weighted excess attenuation for a traffic noise spectrum are made illustrating the effects of varying the depth of the cutting and the absorbency of the surrounding ground surface.

Scattering of electromagnetic waves by rough interfaces and inhomogeneous layers

We consider a two-dimensional problem of scattering of a time-harmonic electromagnetic plane wave by an infinite inhomogeneous conducting or dielectric layer at the interface between semi-infinite homogeneous dielectric half-spaces. The magnetic permeability is assumed to be a fixed positive constant. The material properties of the media are characterized completely by an index of refraction, which is a bounded measurable function in the layer and takes positive constant values above and below the layer, corresponding to the homogeneous dielectric media. In this paper, we examine only the transverse magnetic (TM) polarization case. A radiation condition appropriate for scattering by infinite rough surfaces is introduced, a generalization of the Rayleigh expansion condition for diffraction gratings. With the help of the radiation condition the problem is reformulated as an equivalent mixed system of boundary and domain integral equations, consisting of second-kind integral equations over the layer and interfaces within the layer. Assumptions on the variation of the index of refraction in the layer are then imposed which prove to be sufficient, together with the radiation condition, to prove uniqueness of solution and nonexistence of guided wave modes. Recent, general results on the solvability of systems of second kind integral equations on unbounded domains establish existence of solution and continuous dependence in a weighted norm of the solution on the given data. The results obtained apply to the case of scattering by a rough interface between two dielectric media and to many other practical configurations.

Acoustic scattering by an inhomogeneous layer on a rigid plate

The problem of scattering of time-harmonic acoustic waves by an inhomogeneous fluid layer on a rigid plate in R2 is considered. The density is assumed to be unity in the media: within the layer the sound speed is assumed to be an arbitrary bounded measurable function. The problem is modelled by the reduced wave equation with variable wavenumber in the layer and a Neumann condition on the plate. To formulate the problem and prove uniqueness of solution a radiation condition appropriate for scattering by infinite rough surfaces is introduced, a generalization of the Rayleigh expansion condition for diffraction gratings. With the help of the radiation condition the problem is reformulated as a system of two second kind integral equations over the layer and the plate. Under additional assumptions on the wavenumber in the layer, uniqueness of solution is proved and the nonexistence of guided wave solutions of the homogeneous problem established. General results on the solvability of systems of integral equations on unbounded domains are used to establish existence and continuous dependence in a weighted norm of the solution on the given data.