Hyperon production asymmetries in 500 GeV/c pion nucleus interactions

We present a preliminary study from Fermilab experiment E791 of Lambda^0 / Lambda^0 bar, Xi^- / Xi^+ and Omega^- /Omega^+ production asymmetries from pi^- nucleus interactions at 500 Gev/c. The production asymmetries for these particles are studied as a function of x_F and pt^2. We observed an asymmetry in the target fragmentation region for Lambda^0's larger than that for Xi's, suggesting diquark effects. The asymmetry for Omega's is significatively smaller than for the other two hyperons consistent with the fact that Omega's do not share valence quarks with either the pion or the target particle. In the beam fragmentation region, the asymmetry tends to 0.1 for both Lambda^0's and Xi's. The asymmetries vs pt^2 are approximately constant for the three strange baryons under study.Comment: Typos correcte

Asymmetry studies in Lambda 0/Lambda 0-bar, Xi-/Xi+ and Omega-/Omega+ production

We present a study on hyperon/anti-hyperon production asymmetries in the framework of the recombination model. The production asymmetries for Lambda 0/Lambda 0-bar, Xi-/Xi+ and Omega-/Omega+ are studied as a function of x_F. Predictions of the model are compared to preliminary data on hyperon/anti-hyperon production asymmetries in 500 GeV/c pi- p interactions from the Fermilab E791 experiment. The model predicts a growing asymmetry with the number of valence quarks shared by the target and the produced hyperons in the x_F < 0 region. In the positive x_F region, the model predicts constant asymmetries for Lambda 0/Lambda 0-bar and Omega-/Omega+ production and a growing asymmetry with x_F for Xi-/Xi+. We found a qualitatively good agreement between the model predictions and data, showing that recombination is a competitive mechanism in the hadronization process.Comment: One reference correcte

Método Interativo para Constância de Cor em Vídeos Utilizando Cores Identificadas nas Cenas

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THE SALT CRYSTALLIZATION WEATHERING OF BUILDING ROCKS OF THE ARCHAEOLOGICAL SITES CALCARENITES OF NORTH-WESTERN MOROCCO (LIXUS, BANASA AND THAMUSIDA)

The archeological cities of north-western Morocco: Lixus, Banasa and Thamusida represent an international heritage, with a great social and cultural importance for the history of the country. This work is dedicated to study the salt crystallization weathering, reaching the building rocks of the monuments in order to preserve and restore them. These monuments show a variety of lithological facies implemented in its construction.The degradation of these materials is accelerated by climate influence of El Gharb and Prerif area, characterized by a high humidity and an important atmospheric and soil salinity. The most affected building rocks by the weathering are generally represented by limestones (calcarenites).When salt crystallizes in the pores of the rock after evaporation, the crystal dissociates the grains surrounding by expansion. Therefore, there is a loss of material. The accelerated aging test laboratory shows that calcarenites present the highest rate of weight loss among the samples of different lithologies. This is rendered in a significant susceptibility to degradation; a physical degradation by salt crystals expansion and a chemical degradation by a carbonates dissolution in the presence of the saline fog and a high temperature (50 °C).Lixus calcarenites are more resistant to weathering by salt, when compared to the calcarenites of the other two monuments

Instrumental Properties of Social Testbeds

The evaluation of an ability or skill happens in some kind of testbed, and so does with social intelligence. Of course, not all testbeds are suitable for this matter. But, how can we be sure of their appropriateness? In this paper we identify the components that should be considered in order to measure social intelligence, and provide some instrumental properties in order to assess the suitability of a testbed.Insa Cabrera, J.; Hernández Orallo, J. (2015). Instrumental Properties of Social Testbeds. Lecture Notes in Artificial Intelligence. 9205:101-110. doi:10.1007/978-3-319-21365-1_11S1011109205Horling, B., Lesser, V.: A Survey of Multi-Agent Organizational Paradigms. The Knowledge Engineering Review 19, 281–316 (2004)Simao, J., Demazeau, Y.: On Social Reasoning in Multi-Agent Systems. Inteligencia Artificial 5(13), 68–84 (2001)Roth, A.E.: The Shapley Value: Essays in Honor of Lloyd S. Shapley. Cambridge University Press (1988)Insa-Cabrera, J., Hernández-Orallo, J.: Definition and properties to assess multi-agent environments as social intelligence tests. Technical report, CoRR (2014)Legg, S., Hutter, M.: Universal Intelligence: A Definition of Machine Intelligence. Minds and Machines 17(4), 391–444 (2007)Hernández-Orallo, J., Dowe, D.L.: Measuring universal intelligence: Towards an anytime intelligence test. Artificial Intelligence 174(18), 1508–1539 (2010)Hernández-Orallo, J.: A (hopefully) unbiased universal environment class for measuring intelligence of biological and artificial systems. In: 3rd Conference on Artificial General Intelligence, pp. 182–183 (2010)Hernández-Orallo, J., Dowe, D.L., Hernández-Lloreda, M.V.: Universal psychometrics: Measuring cognitive abilities in the machine kingdom. Cognitive Systems Research 27, 50–74 (2014