Digging for victory amid the lockdown (1)
I read James Wong’s analysis of recent claims that we could become self-sufficient by growing our own fruit and veg amid the pandemic (18 April, p22) with great enthusiasm. I completely agree that achieving this is tough, bordering on impossible, given the very limited space in most gardens.
However, maybe a gardener can be more efficient than industrial-scale agriculture, which was the yardstick for the analysis. This may help improve yields at home.
Use of a small polytunnel would also be a boost. And how about keeping bees as a space-saving solution: a hive occupies little area 鈥� only 50 centimetres by 50 centimetres 鈥� yet can yield 30 to 40 kilograms of honey per year at around 3000 kilocalories per kg.
Digging for victory amid the lockdown (2)
I have heard that some people compensate for lack of garden space by growing and making produce of higher value that is then bartered. For example, a smaller volume of eggs or wine could be traded for a larger volume of potatoes.
In pursuit of the perfect home-made face mask (1)
I have been advocating face masks (18 April, p11)聽for several weeks as a way of slowing the spread of respiratory infections such as covid-19 and, four weeks ago, devised an easy, home-made, five-layer mask from a folded, non-woven kitchen cloth that encloses three layers of paper kitchen towel.
As well as conforming well to the face, the paper can be binned or burned after each use, while the kitchen cloth can be washed overnight then dried. It is easy and cheap to replace as well.
Meanwhile, my sister-in-law, a talented seamstress, has been making two-layer cloth masks for friends who are doctors, as well as family, from dress and curtain off-cuts. Her design is typical of many now being made by home workers.
Which type is better at containing aerosol-borne contagion? Perhaps we need a competition for different home-made designs to test their efficacy.
In pursuit of the perfect home-made face mask (2)
Jessica Hamzelou reports on the mixed evidence for the efficacy of the general use of face masks in the fight against covid-19.
Given their use will probably become more widespread in the future, and is likely to be advocated by governments including ours, there is one situation where face masks will have a significant effect on society: future policing using facial recognition technology might prove a little more difficult.
Return of the birds, clear skies and fresher air
Your pages have been full of stories on the effects of the pandemic on day-to-day life. Here, 30 kilometres from Frankfurt airport, the virus has brought changes, too.
People live, but noise has died. In the garden, where the Boeings fought a winning battle with the larks, the dinosaurs have at last reconquered Earth as birdsong dominates the days.
The motorways, a low drone day and night in the distance, are now, it seems, still. The night sky, recently strewn with diffusing contrails and blinking navigation lights, is clear and still, with only Venus in the west in glory among, suddenly, lots of stars.
The air is clean, nearby factories stilled. No smoke, little pollution in the air. Very few cars and little dust, despite the lack of rain. Only huge, yellow pollen clouds. The air smells green.
Don't forget China's take on the legend of Mulan
In your story about the origins of the Mulan legend (18 April, p15), you mentioned archaeological evidence that it may have been inspired by ancient Xianbei women who were warriors.
What you didn’t mention is that, according to the standard accounts of Hua Mulan in ancient China, it was generally believed that she lived during the Northern Wei dynasty, which was created by the Xianbei who migrated south into northern China in AD 386.
The Xianbei of the Northern Wei dynasty adopted the Chinese language, political system and many aspects of Han Chinese culture and religion. But they also retained many nomadic Xianbei cultural customs too, most notably their military traditions and a higher status and more freedom for women.
This elevated status for women continued into the subsequent Sui and Tang dynasties of China, even though these dynasties were ruled by Han Chinese imperial families.
The archaeological evidence mentioned in the article confirms, to some extent, the standard traditional Chinese account of Hua Mulan as a cross-dressing female warrior of the Northern Wei period.
Invasive species can help control invasive species
In Australia, we had our own little green invader (11 April, p42): a cactus called prickly pear that was introduced in about 1787, only to become an invasive weed by the early 20th century. Then, in 1925, an insect was introduced, Cactoblastis cactorum, which ate the prickly pear and solved the problem. Cane toads, introduced here to control pest beetles, are another story.
How we ended up with a lop-sided natural world
The question of what caused many molecules fundamental to life to be chiral (18 April, p44) 鈥� akin to being either right or left-handed 鈥� is easily solved. Michelangelo’s Creation of Adam clearly shows God using his right hand to give life to Adam.
Quantum humour may prove very elusive
Tom Gauld may have a problem in finding a really good quantum mechanics cartoon (11 April, p26). It might not be possible to know exactly how funny a joke is and unequivocally what it is about at the same time.
Something sweet helps the medicine go down
Liz Berry wrote about the possibility of immunity from pathogens by eating earthworms (Letters, 25 April). Back in the 1950s, my brother was found at the bottom of the garden rolling earthworms in sugar before eating them. He hasn’t suffered from pathogens, but does have high blood pressure 鈥� presumably from all that sugar.