Computational methods for exploring the dynamics of cancer : the potential of state variables for description of complex biological systems

Observing dynamic patterns in silico and comparing them to experimental data in vitro or in vivo could help us identify and quantify dynamic processes. Since modellers are faced with a high degree of complexity of biological systems, appropriate concepts of system descriptions are needed. The use of state variables is expected to make models applicable to a wider range of the dynamics of biological systems. This is demonstrated by the Multi-Hit-Repair (MHR-)model which is based on a transient dose equivalent. The model calculates the survival of cells irradiated by ionizing radiation and it describes correctly a large variety of radio-biological observations. In addition, the MHR-model is bridging the gap between processes at the molecular or cellular level and tissue dynamics

„Arbeitsplatzausstattung“ und „Arbeitsplatzlücke“ nach Geschlechtern in Ost- und Westdeutschland

The paper investigates (a) the number and structure of available jobs by gender in East and West Germany, (b) the gap between the supply and demand of jobs by gender in both regions and (c) the reasons for the wider “job gap” in East Germany compared with West Germany. The paper uses data from the Regional National Accounts and the Federal Labor Office. The analysis shows no significant difference in the number of jobs per 1000 persons in working age between East and West Germany. For women, the East German economy offers more jobs. Nevertheless, the gap between labour demand and the supply of jobs is wider in East Germany. This is caused not only by problems concerning the production structure, but also by the significantly higher partizipation rate of women in the labor market. Reasons are the traditional behaviour of East German woman and – compared with West Germany – the considerably lower household income.employment, underemployment, labor demand, labor supply, East Germany, West Germany

Topologically stable magnetization states on a spherical shell: curvature-stabilized skyrmions

Topologically stable structures include vortices in a wide variety of matter, skyrmions in ferro- and antiferromagnets, and hedgehog point defects in liquid crystals and ferromagnets. These are characterized by integer-valued topological quantum numbers. In this context, closed surfaces are a prominent subject of study as they form a link between fundamental mathematical theorems and real physical systems. Here we perform an analysis on the topology and stability of equilibrium magnetization states for a thin spherical shell with easy-axis anisotropy in normal directions. Skyrmion solutions are found for a range of parameters. These magnetic skyrmions on a spherical shell have two distinct differences compared to their planar counterpart: (i) they are topologically trivial and (ii) can be stabilized by curvature effects, even when Dzyaloshinskii-Moriya interactions are absent. Due to its specific topological nature a skyrmion on a spherical shell can be simply induced by a uniform external magnetic field

FCHgo : fuel cells hydrogen educational model for schools, an imaginative approach to hydrogen and fuel cell technology for young students and their teachers

In this paper we will describe didactic elements in the Horizon 2020 project FCHgo. This project is directed at children and adolescents between 8 and 18 years old. Its ultimate goal is to raise awareness for renewable energy sources, in particular hydrogen as a fuel and fuel cells for electric power. As part of the project, we are developing a toolkit for teachers and pupils, based upon a narrative approach to physical science and engineering. We believe the narrative approach to be best suited for this project because it allows us to take into account the cognitive tools available to pupils at various stages of their development

Resolution of Ultramicroscopy and Field of View Analysis

In a recent publication we described a microscopical technique called Ultramicroscopy, combined with a histological procedure that makes biological samples transparent. With this combination we can gather three-dimensional image data of large biological samples. Here we present the theoretical analysis of the z-resolution. By analyzing the cross-section of the illuminating sheet of light we derive resolution values according to the Rayleigh-criterion. Next we investigate the resolution adjacent to the focal point of the illumination beam, analyze throughout what extend the illumination beam is of acceptable sharpness and investigate the resolution improvements caused by the objective lens. Finally we conclude with a useful rule for the sampling rates. These findings are of practical importance for researchers working with Ultramicroscopy to decide on adequate sampling rates. They are also necessary to modify deconvolution techniques to gain further image improvements