30 research outputs found
Line graphs as social networks
The line graphs are clustered and assortative. They share these topological
features with some social networks. We argue that this similarity reveals the
cliquey character of the social networks. In the model proposed here, a social
network is the line graph of an initial network of families, communities,
interest groups, school classes and small companies. These groups play the role
of nodes, and individuals are represented by links between these nodes. The
picture is supported by the data on the LiveJournal network of about 8 x 10^6
people. In particular, sharp maxima of the observed data of the degree
dependence of the clustering coefficient C(k) are associated with cliques in
the social network.Comment: 11 pages, 4 figure
Próba mykologicznej analizy korzeni świerka (Picea excelsa Lk.) [Versuch einer mykologischen Analyse von Fichtenwurzeln (Picea excelsa Lk.)]
The soliton stars evolution
The evolution of a soliton star filled with fermions is studied in the
framework of general relativity. Such a system can be described by the surface
tension , the bag constant , and the fermion number density
. Usually one of these parameters prevails in the system and thus
affects the spacetime inside the soliton. Whether it is described by Friedman
or de Sitter metric depends on the prevailing parameter. The whole spacetime is
devided by the surface of the soliton into the false vacuum region inside the
soliton and the true vacuum region outside, the latter being described by the
Schwarzschild line element. The aim of this paper is to study the equations of
motion of the domain wall in two cases. In the first case the de Sitter metric
describes the interior in the first case, and in the second case it is replaced
by the Friedman metric. In both of them the Schwarzschild metric is outside the
soliton. From the analysis of obtained equations one can draw conclusions
concerning further evolution of a soliton star.Comment: Latex, 16 pages, 6 eps figures produced by Mathematic
Species diversity of Trichoderma in Poland
In the present study, we reinvestigate the diversity of Trichoderma in Poland utilizing a combination of morphological and molecular/phylogenetic methods. A total of 170 isolates were collected from six different substrata at 49 sites in Poland. These were divided among 14 taxa as follows: 110 of 170 Trichoderma isolates were identified to the species level by the analysis of their ITS1, ITS2 rDNA sequences as: T. harzianum (43 isolates), T. aggressivum (35), T. citrinoviride (11), T. hamatum (9), T. virens (6), T. longibrachiatum (4), T. polysporum (1), and T. tomentosum (1); 60 isolates belonging to the Viride clade were identified based on a fragment of the translation-elongation factor 1-alpha (tef1) gene as: T. atroviride (20 isolates), T. gamsii (2), T. koningii (17), T. viridescens (13), T. viride (7), and T. koningiopsis (1). Identifications were made using the BLAST interface in TrichOKEY and TrichoBLAST (http://www.isth.info). The most diverse substrata were soil (nine species per 22 isolates) and decaying wood (nine species per 75 isolates). The most abundant species (25%) isolated from all substrata was T. harzianum
Monte Carlo simulations of a polymer chain conformation. The effectiveness of local moves algorithms and estimation of entropy
Interactive physiological potential of Peyronellaea curtisii (=Phoma narcissi) strains for enzymatic attack and defence capabilities against phytoalexins
Próba mykologicznej analizy korzeni świerka (Picea excelsa Lk.) [Versuch einer mykologischen Analyse von Fichtenwurzeln (Picea excelsa Lk.)]
Integrated system of managing the safety in the rail transport (4). Safety Management System
Podstawowym założeniem wdrażanego obecnie w Polsce Systemu Zarządzania Bezpieczeństwem (SMS) przewoźników kolejowych i zarządców infrastruktury (w przyszłości również podmiotów utrzymaniowych ECM) jest podejście procesowe