Dominating sets and ego-centered decompositions in social networks

Our aim here is to address the problem of decomposing a whole network into a minimal number of ego-centered subnetworks. For this purpose, the network egos are picked out as the members of a minimum dominating set of the network. However, to find such an efficient dominating ego-centered construction, we need to be able to detect all the minimum dominating sets and to compare all the corresponding dominating ego-centered decompositions of the network. To find all the minimum dominating sets of the network, we are developing a computational heuristic, which is based on the partition of the set of nodes of a graph into three subsets, the always dominant vertices, the possible dominant vertices and the never dominant vertices, when the domination number of the network is known. To compare the ensuing dominating ego-centered decompositions of the network, we are introducing a number of structural measures that count the number of nodes and links inside and across the ego-centered subnetworks. Furthermore, we are applying the techniques of graph domination and ego=centered decomposition for six empirical social networks.Comment: 17 pages, 7 figure

Symmetry Algebra of the Planar Anisotropic Quantum Harmonic Oscillator with Rational Ratio of Frequencies

The symmetry algebra of the two-dimensional quantum harmonic oscillator with rational ratio of frequencies is identified as a non-linear extension of the u(2) algebra. The finite dimensional representation modules of this algebra are studied and the energy eigenvalues are determined using algebraic methods of general applicability to quantum superintegrable systems.Comment: LaTeX, 10 pages , THES-TP/93-13 ([email protected]), ([email protected]

Asset versus consumption poverty and poverty dynamics in the presence of multiple equilibria in rural Ethiopia

Effective poverty reduction programs require careful measurement of poverty status. Several studies have shown conceptually that assets reflecting productive capacity form a more robust basis for identifying the poor than do flow variables such as expenditures or income. Nonetheless, little work has empirically compared poverty measurements based on assets and expenditures. This paper uses panel data from Ethiopia to generate an asset-based poverty classification scheme. Regression results are used to estimate an asset index and classify households into categories of structural poverty. Asset index dynamics are also explored to test for the existence of multiple asset index equilibria; evidence of potential poverty traps. Results provide evidence of multiple equilibria in the study sample as a whole as well as convergence at different levels over space, depending on commercialization opportunities and agroecological factors. The asset-based poverty classifications consistently predict future poverty status more accurately than do income-based measures, confirming that the asset-based measure could be used to more carefully target poverty interventions in rural areas and to more accurately assess the impact of those interventions.asset index, asset poverty, Commercialization, expenditures, income-based measures, index equilibria, Poverty dynamics, Poverty reduction, regression,

El Centro Azucarero Argentino frente a la primera crisis azucarera de sobreproducción : tensiones y conflictos : 1895-1897

El presente artículo examina las estrategias corporativas desplegadas por el Centro Azucarero Argentino (corporación empresaria fundada al calor de los debates parlamentarios en torno al librecambio y el proteccionismo de 1894) ante la primera crisis de sobreproducción. Tempranamente en las reuniones de la Comisión Directiva del Centro Azucarero se comenzaron a estudiar las posibles soluciones ante la crisis que se insinuaba. De esta manera entre los años 1895 y 1897 la asociación ensayó distintas estrategias para neutralizar el descenso del precio del dulce. Durante 1895, la corporación orientó sus acciones a lograr acuerdos de venta entre los fabricantes. Como no se obtuvieron los resultados esperados de estas gestiones, a finales de ese año el Centro optó por presentar ante el Congreso de la Nación un proyecto de ley que facilitara la colocación del excedente de azúcar en el mercado mundial a través del establecimiento de primas a la exportación. Paralelamente a la gestión parlamentaria, impulsó la formación de una Sociedad Anónima que comprara y exportara el excedente de producción. Por último, en 1897 convocó a un Congreso Azucarero presidido por el ex presidente Carlos Pellegrini con el propósito de diseñar un proyecto que contuviera las demandas de todos los industriales.The Centro Azucarero Argentino facing the first crisis of overproduction. Tensions and conflicts, 1895-1897. This paper examines the corporate strategies deploied by the Sugar Argentine Center (entrepreneur corporation founded to the heat of the parliamentary debates concerning the free trade and the protectionism of 1894). Early in the meetings of the managerial commission of the Sugar Center the possible solutions were begun to study before the crisis that was insinuated. Hereby between the year 1895 and 1897 the association tested different strategies to neutralize the decrease of the price of the sweet. During 1895, the corporation orientated his actions to achieve agreements of sale among the manufacturers. Since there were not obtained the results expected from these negotiations, at the end of this year the Center chose to present before the Congress of the Nation a project of law that was facilitating the placement of the surplus of sugar on the world market across the establishment of export bounties. Parallel to the parliamentary management, it stimulated the formation of a Joint-stock company that was buying and exporting the surplus of production. Finally, in 1897 it called for a Sugar Congress presided by the ex-president Carlos Pellegrini with the intention of designing a project that was containing the demands of all the manufacturers.Fil: Lenis, María . Universidad Nacional de Tucumá