Invloeden van oppervlakte-infiltratie ten behoeve van duinwaterwinning op kruidachtige oevervegetaties

Many Dutch coastal dune areas have been infiltrated artificially for public water supply purposes. This infiltration of eutrophic water fosters the occurrence of nitrophilous tall hemicryptophytes in phreatophytic vegetations. The rich and diverse indigenous vegetations of w wet dune slacks have almost completely disappeared from the infiltrated dune areas.This thesis describes investigations into the relation between the vegetation on the banks of natural and artificial dune pools and lakes and the available quantities of macro-nutrients These studies were carried out both in infiltrated and in non-infiltrated dune areas.The vegetation has been analysed by using various ecological parameters. Among the three main macro-nutrients (phosphate, nitrate and potassium), the supply of phosphate due to flowing ground water shows a very significant and probably causal relation with the applied vegetation parameters. In non-infiltrated areas, the supply of macro-nutrients due to mineralization of organic matter appears to dominate the supply due to flowing ground water.</p

Roentgen stereophotogrammetric methods for the evaluation of the three dimensional kinematic behaviour and cruciate ligament length patterns of the human knee joint

Using high-accuracy roentgen stereophotogrammetry, some aspects of the three dimensional kinematics of two amputated knee joints have been studied. Instant axes of rotation, as well as cruciate ligament length patterns, were evaluated as function of the flexion-extension angle. As demonstrated by the results, this method of investigation proved to be most effective, in its accuracy as well as in its flexibility aspects

Dosis-effektrelaties in relatie tot de waterwinning in de duinen

Wetensch. publicatieInstitute of Environmental Science