Variable X-ray Absorption in mini-BAL QSOs
  We present the results of X-ray spectral analysis of two mini-BAL QSOs, PG
1126-041 and PG 1351+640, aimed at getting insights into the physics of quasar
outflows. We find strong X-ray spectral variability on timescales of years.
These variations can be well reproduced by variations of physical properties as
the covering factor and column density of ionized gas along the line of sight,
compatible with radiatively-driven accretion disk wind models.
