Das Gestalten von Geschäftsmodellen als Kern des Entrepreneurship

Das Gestalten von Geschäftsmodellen wird zunehmend zu einem zentralen Gebiet des Entrepreneurship. Entrepreneurship wurde in der Vergangenheit häufig mit dem Begriff Sich-selbstständigmachen gleichgesetzt und der Fokus der Betrachtung auf die Wahl der richtigen Gesellschaftsform oder der geeigneten Finanzierungsstruktur gelegt. Ein Grund für die Vernachlässigung des Geschäftsmodells ist die fehlende Orientierung an den wirtschaftstheoretischen Wurzeln des Begriffs. Wir zeigen in diesem Beitrag, dass, basierend auf den Gedanken von Schumpeter, Kirzner und Drucker, die Innovation und deren erfolgreiche Umsetzung im Markt ein essentieller Bestandteil des Begriffs Entrepreneurship und dass das Gestalten des Entrepreneurial Designs (des neuartigen Geschäftsmodells eines Unternehmens) die Hauptaufgabe des Entrepreneurs ist.Business model design is increasingly playing a central role in entrepreneurship. In the past, the term entrepreneurship has frequently been used interchangeably with the concept of self-employment, and the focus has been on considerations related to selecting the proper legal form for the business or the appropriate financing structure. One reason for this neglect of the business model is the lack of orientation regarding the theoretical economic roots of the concept. In this article, we explain that based on the thoughts of Schumpeter, Kirzner, and Drucker, innovation and its successful realisation in the market are an essential component of the concept of entrepreneurship, and that the entrepreneurial design (the innovative business model of a company) is the main task of the entrepreneur

Numerical simulation of the three-dimensional structure and dynamics of the non-magnetic solar chromosphere

Three-dimensional numerical simulations with CO5BOLD, a new radiation hydrodynamics code, result in a dynamic, thermally bifurcated model of the non-magnetic chromosphere of the quiet Sun. The 3-D model includes the middle and low chromosphere, the photosphere, and the top of the convection zone, where acoustic waves are excited by convective motions. While the waves propagate upwards, they steepen into shocks, dissipate, and deposit their mechanical energy as heat in the chromosphere. Our numerical simulations show for the first time a complex 3-D structure of the chromospheric layers, formed by the interaction of shock waves. Horizontal temperature cross-sections of the model chromosphere exhibit a network of hot filaments and enclosed cool regions. The horizontal pattern evolves on short time-scales of the order of typically 20 - 25 seconds, and has spatial scales comparable to those of the underlying granulation. The resulting thermal bifurcation, i.e., the co-existence of cold and hot regions, provides temperatures high enough to produce the observed chromospheric UV emission and -- at the same time -- temperatures cold enough to allow the formation of molecules (e.g., carbon monoxide). Our 3-D model corroborates the finding by Carlsson & Stein (1994) that the chromospheric temperature rise of semi-empirical models does not necessarily imply an increase in the average gas temperature but can be explained by the presence of substantial spatial and temporal temperature inhomogeneities.Comment: 18 pages, 13 figures, accepted by Astronomy & Astrophysics (30/10/03

g factor of lithiumlike silicon 28Si11+

The g factor of lithiumlike 28Si11+ has been measured in a triple-Penning trap with a relative uncertainty of 1.1x10^{-9} to be g_exp=2.0008898899(21). The theoretical prediction for this value was calculated to be g_th=2.000889909(51) improving the accuracy to 2.5x10^{-8} due to the first rigorous evaluation of the two-photon exchange correction. The measured value is in excellent agreement with the state-of-the-art theoretical prediction and yields the most stringent test of bound-state QED for the g factor of the 1s^22s state and the relativistic many-electron calculations in a magnetic field