...that have always intrigued you about the world will appear in this,
your section, and be answered by other readers. Please address
your answers and questions to ‘Curiosities’.

Why is the depletion of the ozone layer greatest in the southern hemisphere
when the use of ozone-destroying chemicals is greatest in the northern hemisphere?

PANOS PICTURES

It is colder in the Antarctic than the Arctic and low temperatures and ice clouds facilitate destruction of the ozone layer. A band of westerly winds, called the circumpolar vortex, keeps mild air from the equator away from the Antarctic, enabling ice clouds to form there. The ozone hole above the Antarctic is largest in October when spring sunlight first arrives after the long winter and provides energy for the chemical reactions that deplete ozone. But thinning of the ozone layer happens in the North too and we should all be concerned about atmospheric pollution.

Douglas Clark
Reading, UK

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Mosquitoes and other insects insert the equivalent of a micro needle into a variety of human bloods.
So why are they not in the list of transmitters of HIV?

The mosquito is not a carrier of HIV. At each feed it sucks blood for food without injecting any of its last meal because it has already been digested. Like humans, mosquitoes can quite safely eat food that contains HIV because digestion rapidly kills the virus. The only thing which can survive the digestive powers of a mosquito is the organism that causes malaraia. It is so tough that it can survive till the next mosquito feeding time and it can survive the human immune system too. The drugs which kill it very nearly kill the people who have to take them too - and the malaraia virus is increasingly resistant to even those drugs.

Dr JS Barrett
London, UK

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Is it true that the UK is still paying for the First World War and to whom?

Contrary to the answer given in NI 242 Britain ran up huge debts to the US during the First World War and still owes $14 billion. The last token payment was made in December 1933 – though in March 1949 a further $4,480 was paid under the terms of the will of a British subject. The US, apparently unable to force repayment and/or appreciative of Britain’s inability to pay, has made no further demands.

Mark Pack
York, UK

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Is it true that the menstrual cycles of women living together in
women-only communities coincide and if so why?

I assume that your two correspondents in NI 241 were answering this question with flippancy in the April Fool genre.
The truth of the matter is they do not synchronize. I should know: I was 32 years in an enclosed order of nuns.

C Baker-Pearce
Belper, UK

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I’ve recently discovered loo roll made from cotton which is so soft I find it difficult to believe I can use it with a clean conscience. Can anyone advise me whether it’s likely to have been produced in circumstances that are environmentally friendly and politically correct?

Jenny Visick
London, UK

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Which does greater harm to children of an unhappy marriage: a) seeing their parents quarrelling and fighting or b) having their parents living apart, in peace, and sharing responsibility for the children?

Tony Goodchild,
Icarda, Syria

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What are the origins and meaning of the expression ‘ethnic cleansing’? Who first used it?

Kathleen Jones
Bishops Castle, UK

If you have any questions or answers please send them to Curiosities,
New Internationalist, 55 Rectory Road, Oxford OX4 1BW, UK,
or to your local NI office (click here for addresses).

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