Genomic Deletion Marking an Emerging Subclone of Francisella tularensis subsp. holarctica in France and the Iberian Peninsula

P. 7465-7470Francisella tularensis subsp. holarctica is widely disseminated in North America and the boreal and temperate regions of the Eurasian continent. Comparative genomic analyses identified a 1.59-kb genomic deletion specific to F. tularensis subsp. holarctica isolates from Spain and France. Phylogenetic analysis of strains carrying this deletion by multiple-locus variable-number tandem repeat analysis showed that the strains comprise a highly related set of genotypes, implying that these strains were recently introduced or recently emerged by clonal expansion in France and the Iberian PeninsulaS

New Bisimulation Semantics for Distributed Systems

Bisimulation semantics are a very pleasant way to define the semantics of systems, mainly because the simplicity of their definitions and their nice coalgebraic properties. However, they also have some disadvantages: they are based on a sequential operational semantics defined by means of an ordinary transition system, and in order to be bisimilar two systems have to be “too similar”. In this work we will present several natural proposals to define weaker bisimulation semantics that we think properly capture the desired behaviour of distributed systems. The main virtue of all these semantics is that they are real bisimulation semantics, thus inheriting most of the good properties of bisimulation semantics. This is so because they can be defined as particular instances of Jacobs and Hughes’ categorical definition of simulation, which they have already proved to satisfy all those properties

A trace-based view on operating guidelines

Operating guidelines have been introduced to characterize all controllers for a given service S. A controller of S is a service that interacts with S without deadlocking. An operating guideline of S can be used to decide whether S refines another service. It is a special-purpose structure to describe the behavior of service S from the perspective of its controllers rather than from the perspective of S. This paper provides a more conceptual understanding of operating guidelines from the erspective of a traditional concurrency semantics: a trace-based semantics. As benefits, we get an easier characterization of service refinement, and prove that this is a fully abstract precongruence

SNP-based analysis of genetic substructure in the Germany population.

Objective: To evaluate the relevance and necessity to account for the effects of population substructure on association studies under a case-control design in central Europe, we analysed three samples drawn from different geographic areas of Germany. Two of the three samples, POPGEN (n = 720) and SHIP (n = 709), are from north and north-east Germany, respectively, and one sample, KORA (n = 730), is from southern Germany. Methods: Population genetic differentiation was measured by classical F-statistics for different marker sets, either consisting of genome-wide selected coding SNPs located in functional genes, or consisting of selectively neutral SNPs from 'genomic deserts'. Quantitative estimates of the degree of stratification were performed comparing the genomic control approach [Devlin B, Roeder K: Biometrics 1999;55:997-1004], structured association [Pritchard JK, Stephens M, Donnelly P: Genetics 2000;155:945-959] and sophisticated methods like random forests [Breiman L: Machine Learning 2001;45:5-32]. Results: F-statistics showed that there exists a low genetic differentiation between the samples along a north-south gradient within Germany (FST(KORA/POPGEN): 1.7·10-4; FST(KORA/SHIP): 5.4·10 -4; FST(POPGEN/SHIP): -1.3·10-5). Conclusion: Although the FST-values are very small, indicating a minor degree of population structure, and are too low to be detectable from methods without using prior information of subpopulation membership, such as STRUCTURE [Pritchard JK, Stephens M, Donnelly P: Genetics 2000;155:945-959], they may be a possible source for confounding due to population stratification. Copyright © 2006 S. Karger AG