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As spans and slenderness of post-tensioned concrete office floors increase, their vibration behaviour is becoming increasingly important. Although now recognised worldwide to be an important design issue, detailed guidance on the checking of the vibration serviceability of post-tensioned floors is not readily available in national building codes of practice. The only detailed guidelines developed worldwide specifically for checking vibration serviceability of post-tensioned office floors have been published by the UK Concrete Society in 1994. These guidelines are generic, could be and are being used in countries where specific national guidance is lacking. However, the Concrete Society guidelines have been found to be problematic in each of the three key aspects of floor vibration serviceability assessment. First, in the modelling of walking excitation, an unrepresentative walking forcing function is assumed. Second, as the guidelines were not experimentally verified, some unwarranted assumptions and simplifications are made in the modelling of the floor structure, in particular its boundary conditions. Finally, the method of calculation of the floor responses is somewhat simplistic. Here, the possibility that modes of vibration higher than the fundamental may be excited in resonance by walking is neglected.

144 patients with severe rheumatoid arthritis from six centres were randomised to receive oral cyclosporin or placebo for 6 months. The initial daily dose of cyclosporin was 2·5 mg/kg, which was increased cautiously with monitoring of serum cyclosporin levels and creatinine; the mean stabilisation dose was 3·8 mg/kg. There were significant improvements in the cyclosporin-treated patients compared with the controls in the major outcomes of reduction of active joints (23% improvement), pain (24%), and functional status (16%); global improvement was 27%. In the cyclosporin group serum creatinine increased by a mean of 15·6 μmol/l and mean arterial blood pressure by 6·27 mm Hg; these increases were controlled in all but 2 patients by dose adjustment without withdrawal from the study.

An extensive survey of native conifers ( Dacrydium, Podocarpus, Libocedrus, Phyllocladus and Agathis spp.) showed that C 2 H 2 reduction was often associated with their mycorrhizal short roots (‘nodules’). C 2 H 2 reduction was associated with roots only if it also occurred in surrounding soil, but it could be found in soils and not in the root region. Over 50 per cent of the C 2 H 2 reduction activity could be removed by washing roots in distilled water while complete loss of activity occurred when they were surface sterilized with hypochlorite solution. C 2 H 2 reduction may also be associated with long roots of podocarps and roots of non-podocarp species. Fermenting and humifying horizons of forest soils showed much greater rates of C 2 H 2 reduction than either mineral soil or roots. Results suggest that previous claims for nitrogen fixation by podocarp roots can be attributed to nitrogen fixation by bacteria in the root region rather than by endophytic organisms.