Continuous treatment of postmenopausal osteoporosis with calcitriol for three years is safe and significantly reduces the rate of new vertebral fractures in women with this disorder.

SummaryLate Triassic Radiolaria have been recovered from a bedded chert collected early in 1977 in the South Orkney islands. This is the first reliable palaeontological evidence for the age of the so-called basement complex that forms most of the exposed rock of a microcontinent on the southern limb of the Scotia Ridge. The fossils place a lower limit on the age of deformation of at least part of the complex as post-Karnian or Norian. The basement is overlain by undeformed Jurassic to Cretaceous conglomerates, which suggests this event took place during the early Mesozoic Gondwanian orogeny.The new data are consistent with the interpretation that the basement complex of the South Orkney Islands represents part of a subduction complex and was accreted to the Pacific margin of Gondwanaland during the late Triassic or early Jurassic time.

The Antarctic digital topographic database is the outcome of a truly international collaborative project between 11 nations. Data capture was co-ordinated in the UK, under the auspices of the Scientific Committee on Antarctic Research (SCAR), during a two-year period. Over 200 maps, at scales ranging from 1:200 000 to 1:5 000 000, were digitized for the project and reference was made to a similar number of satellite images (mostly Landsat photographic products). Editing and harmonization of the data derived from the different sources has produced a seamless map of Antarctica which has the most up-to-date coastline now available. The topographic database created, to be published on one CD-ROM, will form the foundation for future GIS needs in Antarctic research. Products already derived from the database include digital elevation models and customized maps; the latter can be reproduced by research groups to meet their own mapping needs.