activities of the Research Group 6.13.00 on forest law and environmental legislation and the International Union of Forestry Research Organisations, IUFRO. The Symposium was made possible by a joint effort of IUFRO and the Austrian Federal Ministry of Agriculture and Forestry. We wish to acknowledge

A study commissioned by the

ISBN 3-901676-26-0 Owned and published by the Austrian Federal Ministry for

Abstract. We define the notion of a (weak) almost para-CR structure on a manifold M as a distribution HM ⊂ TM together with a field K ∈ Γ(End(HM)) of involutive endomorphisms of HM. If K satisfies integrability conditions, then (HM, K) is called a (weak) para-CR structure. Under some regularity conditions, an almost para-CR structure can be identified with a Tanaka structure. The notion of maximally homogeneous almost para-CR structure of a semisimple type is defined. A classification of such maximally homogeneous almost para-CR structures is given in terms of appropriate gradations of real semisimple Lie algebras. All such maximally homogeneous structures of depth two (which correspond to depth two gradations) are listed and the integrability conditions are verified.

We consider the full Navier-Stokes-Fourier system in the singular limit for the small Mach and large Reynolds and Péclet numbers, with ill prepared initial data on R 3. The Euler-Boussinesq approximation is identified as the limit system. AMS classification: 35Q30, 35Q31, 34E13

LORENTZPROCESSES

Abstract. In the last couple of years we have evidenced several initiatives promoting the vision of open educational systems. Educational brokers are supposed to take advantage of this ‘infrastructure of standards and open specifications ’ and provide exchange services for users and systems. However, a quick assessment of the adoption of educational brokers leads to the conclusion that educational brokers have still not managed to integrate themselves successfully into the educational landscape. Based on an action research methodology we derive and discuss three design principles that – once implemented – shall lead to an effective brokerage infrastructure. Based on the action research undertaken in two separate research projects we conclude that an effective educational broker needs to: (1) provide a balanced metadata model for learning resource descriptions, (2) take advantage of interoperable ‘home systems ’ that provide services from the user’s most frequently used access point, (3) report on who is re-using what in case ‘open content ’ is brokered.

Available via anonymous ftp from FTP.ESI.AC.AT

Abstract: A Q-manifold is a graded manifold endowed with a vector field of degree one squaring

Abstract. We provide a general mechanism for obtaining uniform information from pointwise data. A sample result is that if a diffeomorphism of a compact Riemannian manifold has pointwise expanding and contracting continuous invariant cone families, then the diffeomorphism is an Anosov diffeomorphism, i.e., the entire manifold is uniformly hyperbolic. 1.