Architecture of packing in molecular crystals

Molecular coordination shells have been used to classify crystal structures into similarity groups.

-invisibility and a class of local similarity groups

In this note we show that the members of a certain class of local similarity groups are ${l}^{2}$-invisible, i.e. the (non-reduced) group homology of the regular unitary representation vanishes in all degrees. This class contains groups of type ${F}_{\infty }$, e.g. Thompson’s group $V$ and Nekrashevych–Röver groups. They yield counterexamples to a generalized zero-in-the-spectrum conjecture for groups of type ${F}_{\infty }$.

Potential infectivity of Anaplasma phagocytophilum strains in Ixodes ricinus ticks from Serbia

Anaplasma phagocytophilumstrains from different geographical regions are characterised by diverse potential infectivity for humans and domesticated animals. We investigated the potential pathogenicity ofA. phagocytophilumstrains inIxodes ricinusticks from 11 geographically different localities in Serbia. Sequences obtained in this study showed a high variability ofp44paralogues. Some of them, however, formed groups with similarities greater than 86% (‘similarity groups’). Previous studies showed that ‘similarity groups’ were nearly always country specific. Our results correlated with this observation, and we also observed significant clustering of paralogues according to vector and reservoir origin ofA. phagocytophilumstrains. According to the high genetic similarity of sequences isolated from ticks collected in four localities, namely Avala, Batrovci, Hajdučka česma and Ljubovija, with paralogues with proven pathogenicity isolated from human granulocytic anaplasmosis (HGA) patients andA. phagocytophiluminfected sheep, we could assume that strains with potential infectivity for humans and domestic animals were present in Serbia.

Genetic relationships among species of the genus Bothrops based on RAPD markers

The genetic relationships among 11 species of Bothrops found in Brazil were determined using random amplified fragment (RAPD) information. A total of 239 amplified bands were scored using 20 aleatory primers. Most of the bands (88.7%) were polymorphic. Phylogenetic analysis of the data determined three similarity groups within Bothrops: Group I- B. alternatus, B. neuwiedi, B. cotiara, and B. jararacusu; Group II- B. insularis, B. jararaca, and B. erythromelas; and Group III- B. moojeni, B. leucurus, and B. atrox. These groups coincided with those obtained by other methods, indicating that RAPD's could be a useful tool for the evaluation of genetic relationships at the interspecific level.