The planning and management of African river and lake basin development and conservation

The success of river and lake basin development and management is rooted in the knowledge of its resources, both physical and human. Within the framework of an integrated basin plan, each economic sector depends on the adequacy of such data for its individual development. The management and conservation of the basin itself in turn depends on knowing the requirements of those sectors and their probable impact on each other and on the status of the basin's resources, its ecology and environment. The development of African river basin resources is subject to various constraints, some for physical and climatic reasons, others tied to socio-cultural characteristics and the priorities of national economies. These are reflected in financial, manpower and institutional limitations, problems of finding technologies suited to specific local conditions and concern for human health. The scale and complexity of river basin development make it difficult to predict precise outcomes of planned proposals, but a progressive approach which links long-term activities with achievable, shorter term production projects offers prospects for ultimate success.     

Uniparental isodisomy for chromosome 16 in a growth-retarded infant with congenital heart disease

We report a growth-retarded infant with congenital heart disease and maternal isodisomy for chromosome 16. Non-mosaic trisomy 16 was detected at mid-trimester chorionic villus sampling, performed because biochemical screening indicated an increased Down's syndrome risk. Further karyotyping analysis of the placenta, after delivery, showed a 50 per cent mosaic trisomy 16. The infant had an atrioventricular (A-V) canal defect, scoliosis, and several minor dysmorphic features. Although uniparental disomy for chromosome 16 has been reported previously, to our knowledge this is the first case of uniparental isodisomy for chromosome 16 which has been investigated with multiple DNA probes.     

The use of tree-rings and foliage as an archive of volcanogenic cation deposition

Tree cores (Pinus nigra ssp. laricio) and leaves (Castanea sativa) from the flanks of Mount Etna, Sicily were analysed by ICP-MS to investigate whether volcanogenic cations within plant material provide an archive of a volcano's temporal and spatial depositional influence. There is significant compositional variability both within and between trees, but no systematic dendrochemical correlation with periods of effusive, explosive or increased degassing activity. Dendrochemistry does not provide a record of persistent but fluctuating volcanic activity. Foliar levels of bioaccumulated cations correspond to modelled plume transport patterns, and map short-term volcanic fumigation. Around the flanks of the volcano foliar variation is greater for volatile cations (Cs, Cd, Pb) than for lithophilic cations (Ba, Sr), consistent with trace-metal supply from volcanic aerosol during quiescent periods.