[en] Wikipedia as a web-based, collaborative, multilingual encyclopaedia project is a very suitable field to carry out research on social dynamics and to investigate the complex concepts of conflict, collaboration, competition, dispute, etc in a large community (∼26 Million) of Wikipedia users. The other face of Wikipedia as a productive society, is its output, consisting of (∼17) Millions of articles written unsupervised by unprofessional editors in more than 270 different languages. In this talk we report some analysis performed on Wikipedia in two different approaches: temporal analysis to characterize disputes and controversies among users and linguistic-based analysis to characterize linguistic features of English texts in Wikipedia. (author)

[en] We present a continuum theory and a Monte Carlo model of self-organized surface pattern formation by ion-beam sputtering including effects of beam profiles. Recently, it has turned out that such secondary ion-beam parameters may have a strong influence on the types of emerging patterns. We first discuss several cases, for which beam profiles lead to random parameters in the theory of pattern formation. Subsequently we study the evolution of the averaged height profile in continuum theory and find that the typical Bradley-Harper scenario of dependence of ripple patterns on the angle of incidence can be changed qualitatively. Beam profiles are implemented in Monte Carlo simulations, where we find generic effects on pattern formation. Finally, we demonstrate that realistic beam profiles, taken from experiments, may lead to qualitative changes of surface patterns.

[en] We present a new Monte Carlo model and a new continuum theory of surface pattern formation due to 'surfactant sputtering', i.e. erosion by ion beam sputtering including a submonolayer coverage of additional, co-sputtered surfactant atoms. This setup, which has been realized in recent experiments in a controlled way leads to a number of interesting possibilities to modify pattern forming processing conditions. We will present three simple scenarios, which illustrate some potential applications of the method. In all three cases, simple Bradley-Harper type ripples appear in the absence of surfactant, whereas new, interesting structures emerge during surfactant sputtering.