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Melting Pot (melting + pot)
Selected AbstractsWORKINGS OF THE MELTING POT: SOCIAL NETWORKS AND THE EVOLUTION OF POPULATION ATTRIBUTES,JOURNAL OF REGIONAL SCIENCE, Issue 2 2007Jan K. Brueckner ABSTRACT This paper links the two nascent economic literatures on social networks and cultural assimilation by investigating the evolution of population attributes in a simple model where agents are influenced by their acquaintances. The main conclusion of the analysis is that attributes converge to a melting-pot equilibrium, where everyone is identical, provided the social network exhibits a sufficient degree of interconnectedness. When the model is extended to allow an expanding acquaintance set, convergence is guaranteed provided a weaker interconnectedness condition is satisfied, and convergence is rapid. If the intensity of interactions with acquaintances becomes endogenous, convergence (when it occurs) is slowed when agents prefer to interact with people like themselves and hastened when interaction with dissimilar agents is preferred. [source] Genome analysis of microorganisms living in amoebae reveals a melting pot of evolutionFEMS MICROBIOLOGY REVIEWS, Issue 3 2010Claire Moliner Abstract Amoebae-resistant microorganisms exhibit a specific lifestyle. Unlike allopatric specialized intracellular pathogens, they have not specialized because they infect the amoebae via amoebal attack and present a sympatric lifestyle with species from different phyla. In this review, we compare the genomes from bacteria (Legionella pneumophila, Legionella drancourtii, Candidatus,Protochlamydia amoebophila,'Rickettsia bellii, Candidatus,Amoebophilus asiaticus') and a virus (mimivirus) that multiply naturally in amoebae. The objective is to highlight the genomic traits characterizing these microorganisms and their niche by comparison with other specialized pathogens. The genome of intra-amoebal microorganisms is significantly larger than that of their relatives, contradicting the genome reduction theory mostly accepted for intracellular pathogens. This is probably due to the fact that they are not specialized and therefore maintain their genome size. Moreover, the presence of many horizontally transferred genes and mobilomes in their genomes suggests that these microorganisms acquired genetic material from their neighbors and amoebal host, thus increasing their genome size. Important features involved in gene transfer and pathogenicity were thus acquired. These characteristics suggest that amoebae constitute a gene melting pot, allowing diverse microorganisms to evolve by the same pathway characterized by gene acquisition, and then either adapt to the intra-amoebal lifestyle or create new pathogens. [source] Facilitation in the conceptual melting potJOURNAL OF ECOLOGY, Issue 6 2009Rob W. Brooker Summary 1. Here we present an introduction to this issue's Special Feature arising from the British Ecological Society Symposium: Facilitation in Plant Communities (20,22 April 2009). 2. Papers in the Special Feature demonstrate the benefits that arise from cross-system application of general concepts, for example, the well-known stress gradient hypothesis. Such comparisons challenge our definition of facilitation, as well as our pre-conceptions on the nature of intermediary organisms. 3. We suggest that under some circumstances a clear definition of the two-way nature of interactions is essential, e.g. when considering the evolutionary implications of facilitation. In other cases, however, we can perhaps be more relaxed, e.g. when facilitation is a component of conservation ecology. 4.Synthesis. Overall we believe that establishing facilitation as an independent concept has driven substantial progress towards a clearer understanding of how ecological systems work. Through the links established by work such as that presented in this Special Feature, we believe this field will continue to make rapid progress and aid ecological understanding in general. [source] | ||||||||||