Wetenschap - 1 januari 1970

Cockroaches

Cockroaches


African farmers for whom stem borers are a problem should be grateful to
creepy crawlies like cockroaches and earwigs.

Farmers in some areas of Kenya grow strips of grass round their maize
fields, and until recently ecologists believed that these encouraged
parasitic wasps that parasitise the eggs of stem borers. New PhD graduate
Dr Linnet Gohole from Kenya conducted experiments and found that grass
strips did not result in more parasitic wasps, but they are home to
cockroaches and earwigs that simply eat up the stem borers. Molasses grass
seems to work well, although other sorts are probably also effective.
According to Gohole one strip of grass should be sown for every five strips
of maize. Another advantage in arid areas is that the grass can be used as
animal feed.

Banana shaped liquid crystals

The Organic Chemistry group is examining a series of banana shaped liquid
crystals which may be suitable for a new generation of fast computer
screens.

The problem with the current generation of liquid crystals is that they
react relatively slowly to electric stimuli, and flat screens in particular
have problems with the quality of moving images. The Wageningen group is
now doing research on a group of curved crystals, of which some may react
faster because of their structure, a fixed bit in the middle and flexible
alkyl groups on the ends. Although the scientists are collaborating with
Philips, the research is not only applied but also fundamental and geared
to the long term.

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