{#intro}
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In the realm of disc galaxies, bars are a common feature observed in approximately 40 per cent of nearby S0–Sm galaxies (e.g. ). In the central regions of these disc galaxies, about one-third have strong barred structure, which generally affects both the motions of stars and interstellar gas and can affect spiral arms as well . In addition, the relative sizes of bars and bulges seems to be correlated [e.g. @2009chas.book..159G], thus indicating that the growth of bars and bulges are somehow connected.

In spiral galaxies, most of the massive star formation occurs in the discs where bars, if present, have a strong impact on the radial distribution of star formation, particularly in early Hubble types. used H$\alpha$ and $R$-band imaging to determine the distributions of young and old stellar populations in several hundreds of nearby S0/a–Im field galaxies. They identified a clear effect of bars on the pattern of massive star formation as a function of radius within discs. This effect results in a strongly enhanced H$\alpha$ emission, and moderately enhanced $R$-band emission in both the central regions and at the bar-end radius of galaxies [see also @2015MNRAS.450.3503J]. The authors noted that this effect seems to be 