A Computable General Equilibrium Approach to Hypothetical Extractions and Missing Links

Identifying key sectors or key locations in an interconnected economy is of paramount importance for improving policy planning and directing economic strategy. Hence the relevance of categorizing them and hence the corresponding need of evaluating their potential synergies in terms of their global economic thrust. We explain in this paper that standard measures based on gross outputs do not and cannot capture the relevant impact due to self- imposed modeling limitations. In fact, common gross output measures will be systematically downward biased. We argue that an economy wide Computable General Equilibrium (CGE) approach provides a modeling platform that overcomes these limitations since it provides (i) a more comprehensive measure of linkages and (ii) an alternate way of accounting for links' relevance that is in consonance with standard macromagnitudes in the National Income and Product Accounts.Economy-wide modeling, Computable general equilibrium, Linkages, Key-sectors

An Applied General Equilibrium Model to Assess the Impact of National Tax Changes on a Regional Economy

This paper presents two versions of an applied general equilibrium model for the regional economy of Andalusia, Spain, that differ in the Public Sector behavior. We intend to exemplify the use of a model with these characteristics to analyze the impact that the reform of the personal income tax (Act 40/98) implemented in Spain as a whole would have had on the Andalusian region in particular. Such an important tax reform is bound to affect the behavior of the agents in this economy, both in the microeconomic and the derived macroeconomic spheres. The general character of the tax reform under analysis and the relations among the different economic agents advise us to use models with these characteristics to study the effects of this reform. The models is of the neoclassical variety and include not only the productive sectors of the economy but also the foreign sector and the government, which are usually absent from theoretical general equilibrium models. Both versions of the model are calibrated by using a Social Accounting Matrix of Andalusia for 1995.applied general equilibrium models, social accounting matrix, fiscal policy, regional economy.

Sensitivity of Simulation Results to Competing SAM Updates

Recently there has been a renewed research interest in the properties of non survey updates of input-output tables and social accounting matrices (SAM). Along with the venerable and well known scaling RAS method, several alternative new procedures related to entropy minimization and other metrics have been suggested, tested and used in the literature. Whether these procedures will eventually substitute or merely complement the RAS approach is still an open question without a definite answer. The performance of many of the updating procedures has been tested using some kind of proximity or closeness measure to a reference input-output table or SAM. The first goal of this paper, in contrast, is the proposal of checking the operational performance of updating mechanisms by way of comparing the simulation results that ensue from adopting alternative databases for calibration of a reference applied general equilibrium model. The second goal is to introduce a new updatin! g procedure based on information retrieval principles. This new procedure is then compared as far as performance is concerned to two well-known updating approaches: RAS and cross-entropy. The rationale for the suggested cross validation is that the driving force for having more up to date databases is to be able to conduct more current, and hopefully more credible, policy analyses.Social Accounting Matrices, Model Evaluation, Applied General Equilibrium, Non-survey Updating Techniques

The Role of Supply Constraints in Multiplier Analysis

Multiplier analysis based upon the information contained in Leontief's inverse is undoubtedly part of the core of the input-output methodology and numerous applications an extensions have been developed that exploit its informational content. Nonetheless there are some implicit theoretical assumptions whose implications have perhaps not been fully assessed. This is the case of the 'excess capacity' assumption. Because of this assumption resources are available as needed to adjust production to new equilibrium states. In real world applications, however, new resources are scarce and costly. Supply constraints kick in and hence resource allocation needs to take them into account to really assess the effect of government policies. Using a closed general equilibrium model that incorporates supply constraints, we perform some simple numerical exercises and proceed to derive a 'constrained' multiplier matrix that can be compared with the standard 'unrestricted' multiplier matrix. Results show that the effectiveness of expenditure policies hinges critically on whether or not supply constraints are considered.Key sectors, Economic linkages, Policy evaluation, Economy-wide modeling, General equilibrium.

VALIDATING POLICY INDUCED ECONOMIC CHANGE USING SEQUENTIAL GENERAL EQUILIBRIUM SAMs

This paper explores the capacity of computable general equilibrium (CGE) models to track down policy induced economic changes and their ability to generate contrastable data for an economy. Starting from an empirically built regional Social Accounting Matrix (SAM), a first stage CGE calibrated model is constructed. The model is then perturbed with a set of policy shocks related to European Union Structural Funds 2000-2005 invested into the region of Andalusia in the south of Spain. The counterfactual equilibrium is translated into a virtual SAM, conformal with the initial one, which is in turn reused to calibrate the next stage in the CGE modeling. And so on until the last stage is reached and all European funds yearly invested have been absorbed by the economy. Since at the end of the process another empirical SAM is available, it can be compared with the terminally produced virtual SAM. The comparison shows the sequence of SAMs to provide a very good fit to the actual data in the empirical SAM. Regional GDP and unemployment rates are two examples of the close approximation. With this novel approach we evaluate, from the methodological viewpoint, the projection capabilities of CGE modeling and at the same time we provide an empirical assessment of the said European policies.Social accounting matrices, applied general equilibrium, impact analysis, European regional policy.

"hauríem d'utilitzar paraules vives i, sempre que es puga, de la nostra gent, del nostre poble". Entrevista a Gerard Vergés

Entrevista a Gerard Vergé

Coupled complex Ginzburg-Landau systems with saturable nonlinearity and asymmetric cross-phase modulation

We formulate and study dynamics from a complex Ginzburg-Landau system with saturable nonlinearity, including asymmetric cross-phase modulation (XPM) parameters. Such equations can model phenomena described by complex Ginzburg-Landau systems under the added assumption of saturable media. When the saturation parameter is set to zero, we recover a general complex cubic Ginzburg-Landau system with XPM. We first derive conditions for the existence of bounded dynamics, approximating the absorbing set for solutions. We use this to then determine conditions for amplitude death of a single wavefunction. We also construct exact plane wave solutions, and determine conditions for their modulational instability. In a degenerate limit where dispersion and nonlinearity balance, we reduce our system to a saturable nonlinear Schr\"odinger system with XPM parameters, and we demonstrate the existence and behavior of spatially heterogeneous stationary solutions in this limit. Using numerical simulations we verify the aforementioned analytical results, while also demonstrating other interesting emergent features of the dynamics, such as spatiotemporal chaos in the presence of modulational instability. In other regimes, coherent patterns including uniform states or banded structures arise, corresponding to certain stable stationary states. For sufficiently large yet equal XPM parameters, we observe a segregation of wavefunctions into different regions of the spatial domain, while when XPM parameters are large and take different values, one wavefunction may decay to zero in finite time over the spatial domain (in agreement with the amplitude death predicted analytically). While saturation will often regularize the dynamics, such transient dynamics can still be observed - and in some cases even prolonged - as the saturability of the media is increased, as the saturation may act to slow the timescale.Comment: 36 page

El impacto de la cobertura mediática de la corrupción en la opinión pública española

Este artículo analiza la cobertura mediática de los escándalos de corrupción en España entre 1996 y 2009. El objetivo es, en primer lugar, determinar hasta qué punto los dos periódicos más leídos en España El País y El Mundo cubren los escándalos de corrupción siguiendo orientaciones políticas distintas. Los resultados ponen de manifiesto una cobertura mediática partidista se identifican diferencias importantes entre ambos periódicos en la cobertura que realizan de los casos de corrupción en función del partido político implicado (PP o PSOE) . En segundo lugar, se analiza si los medios influencian la percepción que los ciudadanos tienen de la corrupción como problema público. Los resultados muestran que cuando aumenta el número de noticias sobre corrupción política, aumenta también el porcentaje de ciudadanos que considera la corrupción como uno de los principales problemas que existen en España. El impacto de los medios sobre la opinión pública es elevado y, además, se produce a corto-medio plazo. Por último, el artículo analiza hasta qué punto la percepción de la corrupción está influenciada por los cambios en la percepción de la situación económica, demostrando que esta variable tiene un poder explicativo bajo en comparación con la cobertura mediátic