Brain workout
Learning a second language has been shown to slow mental decline (7 June, p 14).
However, I suspect that other mental challenges can serve a similar function. My mother regularly devoured a stimulating magazine during her stay in a nursing home. She remained cognisant to the end.
The magazine in question was, of course, 快猫短视频.
Ottawa, Ontario, Canada
For the record
鈥� We got our wires crossed when describing a technique to repair damaged nerves (10 May, p 14). The alloy used contains gallium, indium and tin.
鈥� An elementary error appeared in our feature on the H-bomb curve (7 June, p 42). Carbon-14 decays to nitrogen-14.
鈥� In our story on European migration, we gave a little too much latitude to the labels on the accompanying map (14 June, p 14).
鈥� The act of measuring out David Mermin’s letter on quantum Bayesianism changed its meaning (7 June, p 30). It appears online in full (bit.ly/FTR_qb)
God particle
In their call for a reorganisation of physics principles, David Deutsch and Chiara Marletto argue that the unit of information is more fundamental than anything, even quantum particles (24 May, p 30).
My colleagues will no doubt pelt me with breakfast items for saying this, but I can’t help but be reminded of a rather lovely old book, which begins: “In the beginning was the Word…”
Hong Kong
Man's best friend
I found Robin Dunbar’s essay on friendship to be a fascinating read (24 May, p 34).
However, I was surprised to see that he didn’t include the social carnivores among the “select group of mammals” that form “true friendship” rather than acquaintances.
Ample data show that, like the animals he did include 鈥� higher primates, horses, cetaceans and camelids 鈥� social carnivores form long-term relationships, otherwise known as friendships.
Boulder, Colorado, US
Bird scarer
John Stolarski mentions using stickers in the shape of birds of prey to dissuade pigeons from crashing into clear windows (14 June, p 32).
For years now I have been displaying a very large portrait of my Victorian great-grandfather in my window. Seeing as his bald head, whiskers and scowl can’t put off suicidal birds, I doubt if stickers would help.
Bloxham, Oxfordshire, UK
Space jockey
When the hitchhiking spacecraft tethers itself to a comet, it acts like a regenerative brake, charging its batteries by slowing the comet slightly. The craft uses this stolen kinetic energy to accelerate to the far reaches of the solar system.
Space jockey
You briefly describe a technique in which spacecraft could hitchhike to the far reaches of the solar system on the back of a comet (14 June, p 6).
But if a craft was accelerated to an orbit in which it could catch a comet, surely it could follow this same orbit to the far reaches of the solar system, independently of the comet?
This would be true whether it caught the comet on the way in or on the way out of the solar system. Is the idea perhaps to benefit from any possible shelter the comet might offer as it rounds the sun?
Harrogate, UK
Colour changer
Chlamydomonas nivalis, the “watermelon snow” described by Lisa Grossman in her article on extreme life (14 June, p 13), is not a type of red algae but a green alga in the Chlorophyta phylum. As well as the usual green pigment chlorophyll, it has an additional carotenoid pigment, giving the algae its red colour.
Torquay, Devon, UK
Twist in the tail
Katia Moskvitch’s interview with biologist Michael Levin begins with an error: lizards cannot regenerate lost limbs as claimed (31 May, p 30).
Some can grow a pseudo-tail segment if the tail’s end portion is broken off. It contains no vertebrae as the original did, but instead has a fibrocartilage rod for support and is embossed with a pattern resembling scales.
It is moved primarily by flexing the muscles remaining in the original tail base and thus works similarly to a prosthesis for people who have lost part of their arm or leg.
Manteca, California, US
Science and UKIP
Howard Koch of the UK Independence Party (UKIP) claims his party is pro-science, but I don’t think this extends to climate change (14 June, p 32).
Christopher Monckton, one-time president of UKIP in Scotland, told an audience in the US that the aim of a proposed UN treaty on climate change was to “impose a communist world government”. More recently he was forced to apologise after comparing an .
Derek Clark, the party’s education spokesman, is “We will still ban Al Gore’s video [An Inconvenient Truth] for use in schools if I’ve got anything to do with it. I will not have much opposition within the party,” before concluding “it is, of course, not just this video that needs banning; all teaching of global warming being caused by carbon dioxide emissions must also be banned. It is just not happening.”
Stroud, Gloucestershire, UK
Pyramid scheme
Your special on Scottish independence argues that without continued immigration from Europe and beyond, Scotland will find it difficult to support an ageing population (31 May, p 12).
The same claim has been advanced by Europhiles with regard to other Western European societies, in the wake of growing support for political parties hostile to such migration.
These lead to continuing population growth, since because each generation of immigrants adopts the low birth rates of the indigenous population, they will need to be supported by further immigration.
This sounds to me neither sustainable nor sensible.
Spaxton, Somerset, UK
Watery planet
The discovery of an ocean of water locked in our planet’s mantle also has relevance to other planets (21 June, p 17). The existence of similar reservoirs of hydrated ringwoodite on Mars or Venus would have a major impact on the prospects of terraforming these planets.
Much of the rover exploration on Mars is devoted to finding water. If it isn’t found in large enough quantities, terraforming theorists have identified the icy comets of the Kuiper belt and satellites of Jupiter or Saturn as possible sources of water; but everyone in the field knows what a long shot that is.
The existence of massive underground reservoirs would be a game-changer, as these are more accessible than cometary ice.
Perhaps the next Martian rover should look for the seismic signature of ringwoodite, using a variant of Steven Jacobsen’s methodology as reported in the article. Blue Mars, anyone?
Elblag, Poland
Fire extinguisher
Mark Heinicke suggests that nuclear power can help to combat global warming (7 June, p 31).
However, nuclear and other alternative energy sources will only prevent climate change if they lead to significant quantities of coal, oil and gas remaining in the ground.
Sadly, the growth of the economy and the population, as well as the global desire to emulate Western lifestyles, mean that there is an ever-increasing demand for energy. Increased efficiency and new sources of energy help to meet that growing demand, rather than reducing fossil fuel use. Accessible stocks of these fuels will be burned unless we massively increase their cost, and nobody ever won an election by promising higher fuel prices.
Therefore the current approach to combating climate change will continue to fail. We need another strategy to prevent disaster, one that includes removing carbon dioxide from the atmosphere through reforestation and carbon scrubbing, and artificially cooling the planet by geoengineering.
Hildenborough, Kent, UK
Conception concerns
I was glad to read your article on the debate about legislation regarding so-called three-parent babies (14 June, p 28).
One of the concerns Donna Dickenson and Marcy Darnovsky raised was that it could lead to changes in the law allowing for germ-line modification, DNA changes that are inheritable. I would argue that the techniques, which simply replace harmful mitochondrial DNA (mtDNA) with healthy mtDNA, don’t quite fall into this category.
Also, I find the phrase “three-parent baby” a little too sensationalist. The Nuffield Council of Bioethics has said: “as only part of the donated egg is used and not its nuclear DNA, it is not legally or biologically accurate to refer to the mitochondrial donor as a mother or ‘third parent’ of the resulting child.”
In fact, a bone marrow donor is a better comparison to make with a healthy mtDNA egg donor.
Heaton, Newcastle upon Tyne, UK
Molecular mealtime
While reading Helen Thomson’s discussion of synthetic foods I was amused by the reference to food substitute Soylent.
One hopes this Soylent creation is similar in name only to its literary forebear, and there is no need for the shocking secret ingredient.
Droitwich, Worcestershire, UK
Molecular mealtime
While I don’t begrudge Pierre Gagnarie and his fellow molecular gastronauts their innovation, I concur with Richard Young of the UK Sustainable Food Trust, that molecular gastronomy is at best a red herring, and at worst a failure of holistic thinking when it comes to sustainability (7 June, p 10).
Only once the molecular gastronauts can create food using simple inorganic chemicals recovered from rocks and soil, energy captured from the sun and fewer resources than equivalent farming processes can they consider themselves to be serious contenders in reducing the problems associated with agriculture.
Lincoln, New Zealand
By the numbers
I was pleased to see that your article on paracetamol included the number needed to treat (NNT), which calculates the effectiveness of a medicine by counting the number of patients who need a specific treatment to prevent one additional bad outcome (31 May, p 34).
I wish organisations such as the UK National Institute for Health and Care Excellence would include these figures when publishing findings and guidance, as it makes this information much easier to understand and evaluate, and helps when advising patients.
So it was disappointing that there was no mention of number needed to harm (NNH), the number of people who can be exposed to a treatment before one experiences an adverse effect. This discrepancy led to a huge bias against paracetamol.
In the long term, even when used at standard dosages, aspirin, ibuprofen and equivalent drugs are significantly more likely to cause internal bleeding as well as cardiovascular, cerebrovascular and renal side-effects, which in some people can be fatal.
Perhaps NNT isn’t more widely used because in some situations the NNH may show that the risks outweigh any benefit.
Wath-upon-Dearne, Rotherham, UK