OH-selected AGB and post-AGB stellar objects II.Blue versus red evolution off the AGB

Using objects found in a systematic survey of the galactic Plane in the 1612-MHz OH line, we discuss in detail two ``sequences'' of post-AGB evolution, a red and a blue. We argue that the red and the blue groups separate by initial mass at 4Msun, based on evolutionary-sequence turn-off colours, spectral energy distributions, outflow velocities and scaleheight. The higher-mass (blue) objects may have earlier AGB termination. The lower-mass (red) objects undergo very sudden reddening for IRAS colour R21\sim1.2; these sources must all undergo a very similar process at AGB termination. The transition colour corresponds to average initial masses of 1.7Msun. A combined IRAS-MSX colour proves a very sensitive tool to distinguish lower-mass, early post-AGB objects from sources still on the AGB and also to distinguish more evolved post-AGB objects from star-forming regions. The high-mass blue objects are the likely precursors of bipolar planetary nebulae, whereas the low-mass red objects will evolve into elliptical planetary nebulae.Comment: 12 pages, LaTex, 7 figures (1 colour), AJ (accepted

Vestigingssteun voor bedrijfsopvolgers in de agrarische sector : een analyse van drie mogelijke varianten

In dit rapport is voor drie varianten van vestigingssteun het effect op de financiële positie na de bedrijfsovername onderzocht. De financiële positie na bedrijfsovername is zeer verschillend tussen bedrijven. Deze uitgangssituatie na overname is van essentieel belang voor de levensvatbaarheid. Voor de analyse van de drie varianten is een rekenmodel gemaakt. Van de drie varianten komt de variant zoals die door het Nederlands Agrarisch Jongeren Kontakt is voorgesteld het beste naar voren: het 'Next Generation Fund'. De opvolger ontvangt bij bedrijfsovername 50.000 gulden, die na 10 jaar moet worden terugbetaald. Dit is met name gunstig voor de liquiditeitspositie van de opvolger. Het effect van vestigingssteun op de levensvatbaarheid valt in het niet vergeleken met de effecten van de verschillen in uitgangssituatie

Self-similar decay of high Reynolds number Taylor-Couette turbulence

We study the decay of high-Reynolds number Taylor-Couette turbulence, i.e. the turbulent flow between two coaxial rotating cylinders. To do so, the rotation of the inner cylinder (Re$_i=2 \times 10^6$, the outer cylinder is at rest) is stopped within 12 s, thus fully removing the energy input to the system. Using a combination of laser Doppler anemometry and particle image velocimetry measurements, six decay decades of the kinetic energy could be captured. First, in the absence of cylinder rotation, the flow-velocity during the decay does not develop any height dependence in contrast to the well-known Taylor vortex state. Second, the radial profile of the azimuthal velocity is found to be self-similar. Nonetheless, the decay of this wall-bounded inhomogeneous turbulent flow does not follow a strict power law as for decaying turbulent homogeneous isotropic flows, but it is faster, due to the strong viscous drag applied by the bounding walls. We theoretically describe the decay in a quantitative way by taking the effects of additional friction at the walls into account.Comment: 7 pages, 6 figure