Bars in spiral galaxies can weaken through gas inflow towards the center, and angular momentum transfer. Several bar episodes can follow one another in the life of the galaxy, if sufficient gas is accreted from the intergalactic medium to revive young disks. Pattern speeds of the successive bars are different, due to mass concentration, or increased velocity dispersion of the remaining stellar ...


 Ground level ozone is known to exhibit a strong daily variation of concentration leading long-range transport air pollutants from urban rural areas. Moreover, the characteristics O3 relationship between urban, suburban, and sites can be explained by photochemical chemistry meteorological dispersions as indicated different result diurnal pattern. However, little about global phenomenon oz...

The Chondrostoma genus is widespread in Europe, with numerous endemic species in northern Mediterranean rivers. We reconstructed the phylogenetic relationships of this genus, using the whole cytochrome b sequence and compared the two freshwater fish dispersion hypotheses: (1) dispersion around the Mediterranean Sea during the Lago Mare phase of the Messinian salinity crisis (Bianco's hypothesis...