What Can Arab Countries Learn From Post-communist Transition?

The commentary by Marek Dabrowski on what Arab countries can learn from the post-communist transition of the early 1990s, after the political uprisings against the authoritarian regimes in the Arab world

Oscillating Friedman Cosmology

The non-singular, oscillating Friedman cosmology within the framework of General Relativity is considered. The general oscillatory solution given in terms of elliptic functions and the conditions for its existence are discussed. It is shown that the wall-like-matter and the small, but negative cosmological constant are required for oscillations. The oscillations can , in principle, be deep enough to allow standard hot universe processes like recombination and nucleosynthesis. It is shown that the wall-like-matter and string-like-matter can be interpreted as scalar fields with some potentials. This may give another candidate for the dark matter which may be compatible with observational data. For an exact elementary oscillatory solution it is shown that the associated scalar field potential is oscillating as well.Comment: Latex file, 27 pages, figures available on reques