Kinematics of OB-associations and the new reduction of the Hipparcos
  data
  The proper motions of OB-associations computed using the old (Hipparcos 1997}
and new (van Leeuwen 2007) reductions of the Hipparcos data are in a good
agreement with each other. The Galactic rotation curve derived from an analysis
of line-of-sight velocities and proper motions of OB-associations is almost
flat in the 3-kpc neighborhood of the Sun. The angular rotation velocity at the
solar distance is Omega_0=31 +/-1 km s-1 kpc-1. The standard deviation of the
velocities of OB-associations from the rotation curve is sigma=7.2 km s-1. The
distance scale for OB associations (Blaha & Humphreys 1989) should be shortened
by 10-20%. The residual velocities of OB-associations calculated for the new
and old reductions differ, on average, by 3.5 km s-1. The mean residual
velocities of OB-associations in the stellar-gas complexes depend only slightly
on the data reduction employed.
