Competition, efficiency and collective behavior in the "El Farol" bar model

The El Farol bar model, proposed to study the dynamics of competition of agents in a variety of contexts (W. B. Arthur, Amer. Econ. Assoc. Pap. and Proc. 84, 406 (1994)) is studied. We characterize in detail the three regions of the phase diagram (efficient, inefficient and better than random) of the simplest version of the model (D. Challet and Y.-C. Zhang, Physica A, 246, 407 (1997)). The efficient region is shown to have a rich structure, which is investigated in some detail. Changes in the payoff function enhance further the tendency of the model towards a wasteful distribution of resources.Comment: 7 pages Latex, 7 Postscript figures; changed reference, acknowledgments included. Accepted for publication in Europen Physics Journal

Two triangulations methods based on edge refinement

In this paper two curvature adaptive methods of surface triangulation are presented. Both methods are based on edge refinement to obtain a triangulation compatible with the curvature requirements. The first method applies an incremental and constrained Delaunay triangulation and uses curvature bounds to determine if an edge of the triangulation is admissible. The second method uses this function also in the edge refinement process, i.e. in the computation of the location of a refining point, and in the re-triangulation needed after the insertion of this refining point. Results are presented, comparing both approachesPostprint (published version

Ensemble des possibilités de production, fonction de production et fonction de coût : une présentation de la dualité

L’ensemble des possibilités de production est la représentation première des contraintes technologiques qui font face à une entreprise mono-produit. Sous des hypothèses de régularité de cet ensemble et si le producteur considère les prix comme des données, on construit une fonction de production et une fonction de coût qui contiennent toute l’information économiquement pertinente sur la technologie et on dégage les propriétés minimales que doivent vérifier une fonction de production et une fonction de coût. On indique l’effet que des hypothèses supplémentaires sur l’ensemble des possibilités de production entraînent sur ces fonctions. On montre sous quelles hypothèses on peut construire la fonction de coût directement à partir de la fonction de production et réciproquement; la dualité, ou équivalence informationnelle entre les deux fonctions, est alors mise en évidence par l’égalité entre la fonction de départ et la fonction construite à partir de la fonction duale.The production possibility set is the basic representation of technological constraints faced by a single output firm. If the set satisfies some regularity conditions and if the producer is price-taker, we construct a production function and a cost function containing all the economically relevant information about the technology and we list the minimal properties these functions must satisfy. We exhibit the effects that some additional conditions on the production possibility set have on these functions. We show under which conditions it is possible to construct a cost function directly from the production function and conversely to construct a production function directly from the cost function; the informational equivalence between these functions, the so-called duality, is then presented as the equality of the original function and the function built from the dual one

How Large Is the Private Sector in Africa? Evidence from National Accounts and Labor Markets

In recent years, the private sector has been recognized as a key engine of Africa's economic development. Yet, the most simple and fundamental question remains unanswered: how large is the African private sector? We present novel estimates of the size of the private sector in 50 African countries derived from the analysis of national accounts and labor market data. Our results point to a relatively large size of the African private sector. National account data shows that this accounts for about 2/3 of total investments, 4/5 of total consumption and 3/4 of total credit. In relative terms, large private sector countries are concentrated in Western Africa (Cote d'Ivoire, Guinea, Niger, Senegal and Togo), Central Africa (Cameroun, Republic of Congo) and Eastern Africa (Kenya, Sudan, Uganda and Tanzania), with the addition of Mauritius. Countries with small private sectors include a sample of oil-exporters (Algeria, Angola, Equatorial Guinea, Libya and Nigeria), some of the poorest countries in the continent (Burundi, Burkina Faso, Guinea Bissau, Mali and Sao Tome e Principe), Zambia and Botswana. Over the last ten years, the size of the private sector has been contracting significantly in oil exporting countries, although the variation in its size does not appear to be significantly correlated with growth performance. Labor market data reinforces the idea of a large private sector, which provides about 90% of total employment opportunities. However, most of this labor is informal and characterized by low productivity: permanent wage jobs in the private sector account on average for only 10% of total employment (a share similar to that provided by public administration and state owned enterprises). South Africa is the notable exception, with formal wage employment in the private sector representing 46% of total employment. Finally, we find evidence of negative private sector earning premiums, suggesting that market distortions abound. These are likely to prevent the efficient allocation of human resources, and to reduce the overall productivity of the African economies.private sector size, private sector development, private consumption, private investment, national accounts, private sector employment, private sector earnings, labor markets, Africa

Els apòstols miren al cel. A propòsit de l'edició de les filactèries del frontal de Martinet

This is the fust time the inscripcions from the Martinet altar frontzal are printed, identifying their textual origin (Acts of the Apostels I, 9-1 1) and incluiding the names of all the characters represented. We can note the closse relationship between the images of the altar frontal and the Biblical passage (Acts of the Apostles I, 9-1 I), from wich the painter got his inspiration to paint it

La llengua al Nou Estatut d’Autonomia de Catalunya

1. Presentació. – 2. L’escenari polític i la seva projecció a l’ordenació lingüística estatutària. – 3. Les previsions lingüístiques al nou estatut d’autonomia català. 3.1. El deure de conèixer el català. 3.2. Consolidació de l’estatut d’oficialitat de l’aranès. 3.3. Participació de l’Estat en la projecció exterior de la llengua catalana. 3.4. Reconeixement d’un catàleg de drets i deures lingüístics nous, projectats a diferents àmbits públics. – 4. Epíleg.The purpose of the article is to analyse the linguistic regime established in Catalonia by the new Catalan Statute of Autonomy (new Catalan Statute). After preliminary reflection on the role of the regulation of this regime under the new Catalan Statute, the article discusses the debates on the subject that arose during the drafting process of the later, before examining four specific regulations in it. First, it refers to the obligation to have a knowledge of Catalan and the nature of such an obligation; second, to the consolidation of the legal position regarding the Aranés language ; and—following this—the article analyses the types of participation undertaken by the Spanish central government and the Generalitat (the Catalan Government) in the foreign projection of the Catalan language at European and international levels, and in the relationship held with territories having linguistic associations with Catalonia. Fourth and finally, it assesses recognition of a catalogue of linguistic rights in different public and private sectors (Public Administration and particularly the area of justice, and business) companies). In this sense, therefore, the article carries out a complete analysis of the new Statute’s contributions to the linguistic regime.El artículo tiene por objeto el análisis del régimen lingüístico en el nuevo Estatuto de Autonomía de Cataluña. Tras realizar una reflexión preliminar sobre el papel de la regulación de dicho régimen en la norma estatutaria, se detiene en los debates mantenidos en esta materia durante el proceso estatutario para entrar, a continuación, a examinar la concreta regulación estatutaria. En primer lugar, en lo referido al deber de conocimiento del catalán y al carácter de dicho deber; en segundo lugar, a la consolidación de la posición jurídica del aranés; a continuación analiza las formas de participación del Estado y de la Generalitat en la proyección exterior de la lengua catalana en el ámbito europeo e internacional, y en la relación con los territorios con vínculos lingüísticos con Cataluña; en cuarto y último lugar, se ocupa del reconocimiento de un catálogo de derechos lingüísticos en diferentes ámbitos públicos (administraciones públicas, y en especial el ámbito de la justicia) y privados (empresas). Se acomete, así, el análisis completo de las aportaciones del nuevo Estatuto al régimen lingüístico

El règim lingüístic en la sentència 31/2010, de 28 de juny

Número Especial Sentència 31/2010 del Tribunal Constitucional, sobre l'Estatut d'autonomia de Catalunya de 2006Aquestes pàgines esbossen un comentari crític, molt succint, de la fonamentació jurídica de la STC 31/2010, de 28 de juny, pel que fa a la matèria lingüística. Formalment, aquest comentari jurisprudencial es fonamentarà en una doble premissa: en primer lloc, la constatació que la STC 31/2010, de 28 de juny, ha jutjat els eixos vertebradors del règim lingüístic vigent a Catalunya bo i avalant la seva constitucionalitat; en segon lloc, es partirà de la base que la interpretació secundum constitutionem d'algunes previsions lingüístiques de l'Estatut és tan forçada que, en certs casos, desdibuixa el sentit de l'enunciat literal de la norma, cosa que genera una certa inseguretat jurídica.Estas páginas esbozan un comentario crítico,muy sucinto, de la fundamentación jurídica de la STC 31/2010, de 28 de junio, con respecto a la materia lingüística. Formalmente, este comentario jurisprudencial se fundamentará sobre una doble premisa: en primer lugar, la constatación de que la STC 31/2010, de 28 de junio, ha enjuiciado los ejes vertebradores del régimen lingüístico vigente en Cataluña avalando su constitucionalidad; en segundo lugar, se partirá de la base de que la interpretación secundum constitutionem de algunas previsiones lingüísticas del Estatuto resulta tan forzada que, en ciertos casos, desdibuja el sentido del enunciado literal de la norma generando incluso cierta inseguridad jurídica

El Règim juridicolingüístic a l'administració de justícia

Consultable des del TDXTítol obtingut de la portada digitalitzadaVegeu tes

La postmodernidad : bases filosóficas y valores

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