Smell of fear
Linda Geddes reports that mice can inherit a fear response via epigenetic changes 鈥� chemical changes to the DNA that can turn genes on and off (7 December, p 10). Exposure of the father or grandfather to an odour and an electric shock resulted in offspring that were more jumpy in the presence of the same odour. The question is posed: “How could a fearful memory of a smell wheedle its way into eggs and sperm and change the behaviour of future generations?”
This strikes me as the same question as how instinctive behaviour in any species is passed down the generations. For decades I have believed that the genome, which holds not only the specification of the entire physical organism but also instructions for its growth, maturation and (aspects of) its behaviour, must also be the mechanism of conscious and unconscious memory.
If DNA can achieve all these roles, then it is surely only a matter of time before we discover which sequences encode what information and how, and which may then also get carried over into the genome of the generations that follow.
Saltdean, East Sussex, UK
Smell of fear
I am perplexed. We were all toilet trained and taught our mother tongue, and so were generations of our ancestors, yet we still have to teach our children so many skills. Where did we go wrong? Were we not punished enough for failure to learn? Should we bring back the birch and strong smells? It didn’t work first time around. What have mice got that we haven’t?
Maidenhead, Berkshire, UK
Hands off
I find John Crowhurst’s letter proposing Australia’s outback as a dumping ground for the world’s nuclear waste offensive (30 November, p 33). It is arrogant to ignore the original inhabitants of this land, who continue to live there. We really don’t want this country used as a dumping ground for any form of waste, nuclear or otherwise.
Canberra, ACT, Australia
We're all different
David Whitebread and Sue Bingham argue against accepting children into formal schooling at young ages as if children make up a single entity (16 November, p 28). Nothing could be further from the truth. Some children can read books aimed at 7 to 8-year-olds at the age of 3. Some will never learn to read.
There are roughly Gaussian distributions of abilities in mathematical, artistic, musical and social capabilities. It is ludicrous to promulgate rules that restrict entry into schools based on age. It is far more appropriate to consider each child as an individual with a particular suite of skills, and base entry to a particular school or programme on those skills.
La Jolla, California, US
Slippery slope
Your analysis of talk of a slowdown in global warming (7 December, p 34) misses what seems an obvious factor 鈥� the latent heat of fusion of melting ice. It takes about 40 times as much energy to warm water from -0.5 掳C to 0.5 掳C as it does to go from 1 掳C to 2 掳C.
When excess energy trapped by rising atmospheric carbon dioxide is being used to melt ice it isn’t increasing Earth’s temperature. When the Arctic ice is all gone the temperature of the northern hemisphere will really start to rise.
Oxford, UK
Environment features editor Michael Le Page writes:
鈥� You are right that melting ice soaks up energy without raising temperature. However, according to the Intergovernmental Panel on Climate Change, only about 2 per cent of the excess energy is going into melting ice, as our graph “Where is the heat going?” showed. This is fortunate because, as oceanographer Jochem Marotzke told me, it takes a lot less energy 鈥� two orders of magnitude 鈥� to raise sea level by melting ice than by warming water. Seawater doesn’t expand much as it warms, so it takes a lot of heat energy to produce a small volume change. Melting ice on land also takes a lot of heat energy, but the entire volume ends up in the sea.
Slippery slope
As I bought my copy of 快猫短视频 with the front cover asking: “Is it time to stop worrying about climate change?”, a typhoon Haiyan appeal envelope from the British Red Cross fell out. The answer, in short, is no.
London, UK
Haunting thought
I suspect the discomfort that most people feel at the notion that they are “just” their physical brain is due to an insufficient respect for matter (30 November, p 30).
Physicists know that matter isn’t the lumpen stuff we usually take it for. The closer you look at matter the more it dissolves before your eyes.
Mass, the quantification of stuff, is actually the field energy generated by the Higgs or gluon fields. And it may be that the fundamental particles will ultimately be understood as purely geometrical entities. Thus physics edges ever closer to idealism, the idea that reality is immaterial in nature.
So people shouldn’t worry that there is no ghost in the machine. The truth is quite the opposite: there is no machine. It’s ghost all the way down.
Wotton-under-Edge, Gloucestershire, UK
Safer cycling
An important point was missed when discussing cycling safety in London and the Netherlands (30 November, p 14). As more people cycle, there is an increased likelihood that those who drive cars are also cyclists.
In the Netherlands there is a small core of drivers who never ride a bike, and a small number of adult cyclists who don’t drive; but most do both. This improves driver awareness and makes it more likely that cyclists have some idea what a car driver can and cannot see.
There is one worrying statistic for Dutch cyclists: killed or injured while cycling has increased sharply in the past two years.
This seems to be largely down to the increased use of battery-assisted bikes, which can dramatically increase the speeds that are possible. Between July 2011 and June 2012, 13 per cent of cyclists needing treatment in hospital had been riding these bikes; the average age of the casualties was 66.
The Hague, The Netherlands
One-upmanship?
Keith Hudson’s letter talks about a “keeping up with the Joneses” attitude among individuals as being beneficial at the group level as it boosts economies (7 December, p 32). But what about considering the influence of “powering down with the Joneses” to help fix the climate?
Just challenge the neighbours: “We use far less energy than anyone else in the street, we only had to pay 拢500 for gas and electricity this year, what about you?” Or: “Look at my 1920s dress; it belonged to my great grandmother 鈥� I bet you haven’t got anything that beautiful!”
Birmingham, UK
Strange idea
The material at the centre of a neutron star isn’t stable except under star-mass gravity 鈥� it decays into everyday matter as some of the electrons and protons separate out. But now lower energy strange-quark matter is hypothesised to form in a collapsing neutron star (7 December, p 42).
If it is indeed lower energy than everyday matter, it should be able to exist without lots of gravity to hold it together. And given that the shock wave of a collapsing neutron star ejects material from the surface, shouldn’t there be a large number of lumps of this strange stuff drifting about? The chances are some of this must have fallen to Earth in the past 4 billion years.
All we have to do now is to figure out how to find it.
Oldbury on Severn, Gloucestershire, UK
Need for speed
Jessica Griggs revealed an inconvenient truth about conservationists in her look at the role synthetic biology could play in that field (7 December, p 46): they were “wary of synthetic biology being used as a convenient quick fix” in place of the harder task of changing people’s behaviour.
A convenient quick fix? As opposed, perhaps, to a slow, inconvenient non-fix that requires we “change” people 鈥� that is, control them?
While I sympathise with scepticism about the actual speed or convenience of any given programme, this kind of talk of opposing speed and ease themselves is perverse.
San Francisco, California, US
Hit a brick wall
Your article on the addition of waste brewery grain to the brick-making process and the advantages this brought was very interesting (30 November, p 23). I was involved in a similar trial several years ago using steam-sterilised cellulose fibre from municipal waste as an additive. This also improved the strength and thermal efficiency of the bricks, and diverted waste from landfill sites.
Other benefits, not mentioned in your article, included a reduction in energy consumption within the firing kiln, a lighter brick, less need for costly sand additives in the clay mixture, less need for hazardous additives used to avoid salt marks on the bricks and the potential to include small amounts of waste glass for decorative effects.
Ultimately, regulations on brickworks and the use of “waste” in industrial processes brought the project to a halt. This goes to show that even the best ideas can get swamped by red tape.
Gateshead, UK
Long live Gaia
I agree with the letter from Ken Steele, that the Gaia hypothesis isn’t outdated (7 December, p 32). However, rather than having “humanity cancer” I would say Gaia has a parasitic infection.
And so the question we need to ask is will the parasite destroy its host, and itself in the process, or will Homo sapiens evolve into a more benign species and enter into a symbiotic relationship with Gaia?
Abinger Hammer, Surrey, UK
Too hot to handle
Julien Glazier refers to Fergus Gibb’s idea of packaging the hottest nuclear waste into tungsten capsules and letting them melt their way down through the Earth’s crust (7 December, p 32). Surely if our hottest nuclear waste was really as (thermally) hot as that, and would remain so for a protracted period, we wouldn’t call it waste at all. We would put it in those capsules and drive a power station with it.
Ely, Cambridgeshire, UK
Pre-Darwin
If Alfred Russel Wallace and Patrick Matthew both deserve credit for the theory of evolution alongside Charles Darwin (23 November, p 34), what about the Baghdadi scholar al-Jahiz?
In the 9th century, 1000 years before Darwin, al-Jahiz wrote in his vast Book of Animals: “Animals that survive to breed can pass on their successful characteristics to their offspring.” Here is evolution by means of natural selection in a nutshell.
New Brunswick, New Jersey, US
For the record
鈥� In the article on the pace of global warming, we reversed the wind directions during El Ni帽o and La Ni帽a episodes (7 December, p 34). During La Ni帽a the winds are easterly, and vice versa.