New labour on Algols: conservative or liberal?

I consider three topics related to the influence of magnetic braking, combined with tidal friction, on the orbital evolution of CVs. Firstly, I attempt to how that properties of Algols are roughly consistent with the view that angular momentum loss (AML) takes place in systems with cool (G/K) components, but not in systems with hot (B/A) components. This is what one might expect if the AML requires an active dynamo as seen in the Sun and other cool stars. The timescale required is roughly of the order of what might be expected by magnetic braking. Some enhanced mass loss (ML), presumably by stellar wind, also seems to be necessary in the more evolved Algol systems. Secondly, I urge that theorists adopt a recipe for magnetic braking that is more on the lines of Sepien (1995) than of Skumanich (1972). Thirdly, I argue that 'interrupted magnetic braking', a mechanism often invoked to explain the upper edge of the period gap in CVs, is not in accord with observed properties of late M dwarfs and brown dwarfs, and that some other mechanism should be sought. (C) 2000 Elsevier Science B.V. All rights reserved.