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	Issue 17

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Pesticides — the pests are fighting back
Malaria has staged a disturbing resurgence in many tropical countries recently. In India, for example, the number of reported cases fell from 100 million in 1952 to just 60 000 in 1962, but had risen again to 6 million by 1976. A large part of the cause of the disease's comeback is the development by malaria-spreading mosquitoes of resistance to insecticides used in control programs.
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Saving fuel in cities With the price of petrol and other liquid fuels rising inexorably and the possibility of future shortages looming, the search has begun in earnest for ways to cut down on consumption. Download Article

Preventing birdstrikes at airports Some places just aren't meant to be a naturalist's paradise. For instance, take a large area of open country near one of our major cities and completely strip it of trees. Then cover a goodly amount of it with bitumen. Download Article

Better surfaces for solar collectors
The prime difficulty in harnessing solar energy is that its source is 150 million kilometres away. Using a flat-plate solar collector to collect the sun's heat is like trying to heat water with a camp-fire when the billy is sitting next to you a comfortable distance from the fire. There's no doubt the water will get warm, just as you do, but there's little chance of it boiling. That's one way of looking at the problem of designing more-efficient solar collectors.
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A non-flush toilet assessed An estimated 25–45% of the water supplied to Australian households goes down the toilet. Clearly, methods of sewage disposal that don't use water have big advantages in terms of conservation of precious water resources. Download Article

The noise that offends Domestic air-conditioners are now quieter than they used to be, but CSIRO research confirms that they still have ample room for improvement. Download Article

A wheel to recycle energy A device that has appeared on the market in Japan allows you to let in fresh air on a winter day without letting the cold in. It is a wheel, which fits into an opening in the wall and slowly rotates. Cold fresh air passed through one half of the wheel by a fan is warmed by the warm stale air passed out through the other. Download Article

Black cockatoos and fallen trees
?I have seen, more than once, small trees lying prostrate, occasioned by the powerful bills of the large black cockatoo, who, on observing on the trunk, externally, indications of a larva being within, have diligently laboured to extract it; and should the object of their search be situated (as often occurs) far in, before they reach it, the trunk is so much cut through that the slightest puff of wind lays it prostrate.?
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From soil to stratosphere?
Of all the suggested threats to the earth's protective ozone layer, perhaps the most insidious is the growing use of nitrogen fertilizers and nitrogen-fixing plants. The fear is that worldwide increases in the levels of soil nitrogen will boost the emission rate of nitrous oxide from the ground and that this will reduce ozone concentrations in the upper atmosphere.
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The devil once roamed widely The first white settlers of Tasmania found two dog-sized flesh-eating marsupial species roaming the countryside. The animals' appearance and manner moved the newcomers to christen them the Tasmanian tiger and devil. Download Article