479 research outputs found
Skandinaviske studier og geopolitik: IASS og den kolde krig
The foundation stone for the creation of IASS was laid at the First International Conference on Scandinavian Studies which took place at the University of Cambridge, England, in July 1956. Few months later, the world woke up to the news of the Soviet invasion in Budapest on November 4th, a defining moment in the history of the Cold War, which sent political shock waves and a flow of nearly a quarter-million Hungarian refugees to Western Europe. But how did this tense political situation affect the emerging field of international Scandinavian studies? Drawing on the vast literature of published proceedings from IASS conferences and personal interviews with members of the organization, this article examines how the Cold War geopolitical conflict between the communist East and the capitalist West left its imprint on the activities of IASS in the period from 1956 until the Fall of the Berlin Wall and the dissolution of the Soviet Union in 1989/1991
Lattice gas cellular automata model for rippling and aggregation in myxobacteria
A lattice-gas cellular automaton (LGCA) model is used to simulate rippling
and aggregation in myxobacteria. An efficient way of representing cells of
different cell size, shape and orientation is presented that may be easily
extended to model later stages of fruiting body formation. This LGCA model is
designed to investigate whether a refractory period, a minimum response time, a
maximum oscillation period and non-linear dependence of reversals of cells on
C-factor are necessary assumptions for rippling. It is shown that a refractory
period of 2-3 minutes, a minimum response time of up to 1 minute and no maximum
oscillation period best reproduce rippling in the experiments of {\it
Myxoccoccus xanthus}. Non-linear dependence of reversals on C-factor is
critical at high cell density. Quantitative simulations demonstrate that the
increase in wavelength of ripples when a culture is diluted with non-signaling
cells can be explained entirely by the decreased density of C-signaling cells.
This result further supports the hypothesis that levels of C-signaling
quantitatively depend on and modulate cell density. Analysis of the
interpenetrating high density waves shows the presence of a phase shift
analogous to the phase shift of interpenetrating solitons. Finally, a model for
swarming, aggregation and early fruiting body formation is presented
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