Real-time quantitative PCR assays were developed for the absolute quantification of different groups of bacteria in pure cultures and in environmental samples. 16S rRNA genes were used as markers for… (More)

Let G be a (finite) group and let S be a non-empty subset of G. The vertex set of the orbit graph O(G, S) is the union, over all s ∈ S, of orbits of left translations induced by s. If u and v are… (More)

We study from the metrical and topological point of view the properties of sequences of positive integers which consist in fact that the sequences contain arbitrarily long arithmetical progressions… (More)

We show that the result of Watkins (1990) [19] on constructing vertex-transitive nonCayley graphs from line graphs yields a simple method that produces infinite families of vertex-transitive… (More)

The link of a vertex v in a graph G is the subgraph induced by all vertices adjacent to v. If all the links in G are isomorphic to the same graph L, then L is called the link graph of G. We consider… (More)