Advertising for health?

A SURVEY was carried out to examine the balance between health-promoting advertisements and those for potentially health-damaging products in central Belfast. The latter group included tobacco products, alcohol and confectionery. All advertise ments on hoardings within a one kilometre radius of the centre of Belfast were assigned to one of four categories: advertisements for potentially health- damaging products, advertisements containing health promotion messages, advertisements making health claims, and neutral advertisements. Adver tisements for potentially health-damaging products outnumbered those carrying health promotion mess ages by a ratio of ten to one. The total area of ad vertising space devoted to these products was substantially greater than the area devoted to health promotion messages, as was the amount of money spent on advertising them. While it is recognised that the advertising of health promotion messages may have a limited role in health promotion cam paigns, there are a number of factors which should be considered before using this method of communication. © 1991, Sage Publications. All rights reserved

Microbial ecology of the cryosphere: sea ice and glacial habitats

The Earth's cryosphere comprises those regions that are cold enough for water to turn into ice. Recent findings show that the icy realms of polar oceans, glaciers and ice sheets are inhabited by microorganisms of all three domains of life, and that temperatures below 0 °C are an integral force in the diversification of microbial life. Cold-adapted microorganisms maintain key ecological functions in icy habitats: where sunlight penetrates the ice, photoautotrophy is the basis for complex food webs, whereas in dark subglacial habitats, chemoautotrophy reigns. This Review summarizes current knowledge of the microbial ecology of frozen waters, including the diversity of niches, the composition of microbial communities at these sites and their biogeochemical activities