We performed numerical 3-d MHD simulations to study whether or not the presence of helicity is a necessary ingredient for fast dynamo action. A steady 3-d flow with no mean helicity is used and is turned out that apart from the high growth rate in the linear regime the dynamo saturates at a level significantly higher that the intermittent turbulent

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We present merger models suggesting that bulge growth via accretion of dense satellites generates two of the observed trends of galaxies along the Hubble sequence, namely the increase of Sersic index toward more massive bulges, and the appearance of a thick disk with higher scale length than that of the thin disk. We argue that bulges with

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