New Scientist Australian Edition 26-Sep-20

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THE sharp-eyed among you will have already noticed a few changes to the Back Pages section of the magazine. In the last issue we welcomed back Abigail Beall’s Stargazing at home column, in which she explained how to see a SpaceX Starlink satellite. Her column will now appear every four weeks, on a rotation with three other columns, two new ones and another returning favourite. This week it’s the turn of a fresh offering, Science of gardening, written by medical reporter/allotmenteer Clare Wilson. She begins with a trend in architecture to cover walls with plants to help insulate buildings, soak up rain and give wildlife more space. However, this usually requires complex structures to support the soil. There is another way to get these benefits, though, which Clare tells you…

THE theory of evolution is one of the greatest accomplishments of the human intellect. Some might argue that it is the greatest, although quantum theory or relativity would have their supporters too. But in the biological sciences, it stands unrivalled. It is no less than the grand unified theory of life. It is also a theory in the truest sense of the word: an interlocking and consistent system of empirical observations and testable hypotheses that has never failed scrutiny. Nothing has even been discovered that falsifies any part of it, despite strenuous efforts by detractors. It all stacks up. Yet we should resist the temptation to think that evolution is carved in tablets of stone. The radical but irresistible ideas put forward by Charles Darwin and Alfred Russel Wallace in…

INDIA is on track to overtake the US as the country with the highest number of coronavirus cases worldwide. With more than 5.56 million recorded cases, India set a new record with 97,859 daily cases on 16 September. It took just 11 days for the total number of cases so far to rise from 4 to 5 million, and it is likely to be just a matter of weeks before the country passes the US, which has some 6.85 million cases. Given India’s population of about 1.38 billion, however, the number of cases is comparatively low. On 22 September, for instance, the seven-day average of daily confirmed cases in the US was 131 per million people, compared with 65 per million in India. Deaths, too, currently totalling about 89,000 in…

THIS month, UK Prime Minister Boris Johnson announced an ambition to increase the country’s capacity for coronavirus testing to several million tests a day. Billed as Operation Moonshot, the idea was received with widespread incredulity. The UK is currently failing to meet demand for coronavirus testing, with roughly half a million daily requests outstripping supply by up to fourfold. Yet there are also reports of new technologies in development that could make testing faster and cheaper. If the UK had the capacity to test not just those with symptoms of covid-19, but to regularly test symptomless people too, it could be a game changer in the ability to control the disease. From the beginning of the pandemic, many countries have struggled to provide enough coronavirus tests for all those who…

Any mass screening of people who don’t have symptoms can hit the problem of “false positives”. Imagine a test that is 95 per cent accurate when it produces a positive result. It is important to remember that very few of the screened group really are infected – say about one in 1000 at any time. Of the 999 people without the coronavirus, 949 would correctly test negative, and 50 would wrongly test positive. Assuming that the one person out of the 1000 who really has the virus correctly tests positive too, then for every 51 positive test results, 50 would be wrong. Across the population, that would lead to thousands of people unnecessarily staying at home and self-isolating. There is a solution, says Julian Peto at the London School of Hygiene…