On the variational distance of two trees

A widely studied model for generating sequences is to ``evolve'' them on a tree according to a symmetric Markov process. We prove that model trees tend to be maximally ``far apart'' in terms of variational distance.Comment: Published at http://dx.doi.org/10.1214/105051606000000196 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Comparative analysis of 18S rRNA genes from Myxobolus aeglefini Auerbach, 1906 isolated from cod (Gadus morhua), Plaice (Pleuronectes platessa) and dab (Limanda limanda), using PCR-RFLP

The myxosporean parasite Myxobolus aeglefini is a marine species, which can be found in the cartilage of mainly gadid fish species. The parasite has, however, been recorded in the flatfish plaice (Pleuronectes platessa) and dab (Limanda limanda). It is not clear if isolates from unrelated hosts represent the same species. Therefore a molecular study was conducted to reveal differences at the DNA level between these isolates. PCR was successfully conducted on three different isolates of Myxobolus aeglefini sampled from cod (Gadus morhua), plaice and dab respectively, using 18S rDNA as template. A PCR product of approx. 1600 base pairs was obtained and RFLP (Restriction Fragment Length Polymerase) was conducted on the fragment with the restriction enzymes Hinf I, Msp I and Hae III. No differences between the isolates were found, suggesting that the three isolates represent the same species

Stochastic integration based on simple, symmetric random walks

A new approach to stochastic integration is described, which is based on an a.s. pathwise approximation of the integrator by simple, symmetric random walks. Hopefully, this method is didactically more advantageous, more transparent, and technically less demanding than other existing ones. In a large part of the theory one has a.s. uniform convergence on compacts. In particular, it gives a.s. convergence for the stochastic integral of a finite variation function of the integrator, which is not c\`adl\`ag in general.Comment: 16 pages, some typos correcte

Dynamics of Anguillicola crassus (Nematoda: Dracunculoidea) infection in eels of lake Balaton, Hungary

Following the introduction of Anguillicola crassus into Lake Balaton, by 1991 the entire eel population became infected. At the same time, marked differences existed in the prevalence and intensity of infection between different areas of the lake. The highest prevalence values occurred in the eastern basin less densely populated with eels, while in the western basin a large proportion of the fish were free of infection. Helminth-free status accompanied by thickening of the swimbladder wall developed after intensive infections. In 1991, eel mortality could be observed only in the western basin. In 1992, the number of eels with swimbladders having a thickened wall but not containing helminths increased also in the central and eastern areas of the lake. Parallel to this, a mortality less expressed than the one in 1991 occurred in the central part of the lake. By 1993, a host-parasite equilibrium had become established in Lake Balaton

Distances Between Formal Theories

In the literature, there have been several methods and definitions for working out whether two theories are "equivalent" (essentially the same) or not. In this article, we do something subtler. We provide a means to measure distances (and explore connections) between formal theories. We introduce two natural notions for such distances. The first one is that of axiomatic distance, but we argue that it might be of limited interest. The more interesting and widely applicable notion is that of conceptual distance which measures the minimum number of concepts that distinguish two theories. For instance, we use conceptual distance to show that relativistic and classical kinematics are distinguished by one concept only. © 2019 BMJ Publishing Group. All rights reserved