Less haste
You reported on the proposal for a US hypersonic uncrewed aircraft – Lockheed Martin’s SR-72 equipped with a Mach-3 busting scramjet with built-in jet engines (9 November, p 4). It’s easy to make an aircraft go faster by putting bigger engines on it. What wasn’t mentioned in the article are the real obstacles to practical hypersonic flight.
First is heating of the aircraft’s outer skin. If you upgrade from Mach 3 to Mach 6, there is more skin friction, and to cruise at that speed you need to use special alloys and cooling systems to stop the aircraft melting.
Then there is fuel consumption. Doubling the speed means you roughly , so you burn through the fuel in a quarter of the time. The SR-72’s predecessor, the SR-71, was already a flying fuel tank. There’s really no point in charging around at Mach 6 if you have to drop to subsonic speeds every hour or so to refuel.
Jomtien, Thailand
Feeding debate
You wrote about the launch of a pilot scheme offering shopping vouchers to mothers who breastfeed their babies for the first six months (16 November, p 5). We know that breastfeeding has long-term benefits for the baby, and most mothers in the UK have now heard the “breast is best” message loud and clear.
Yet despite years of health promotion efforts, breastfeeding rates are still low, and with clear social patterning. We urgently need new approaches to encourage and support breastfeeding. Financial incentives have proved modestly effective in changing some other health-related behaviours, so it is not unreasonable to ask whether it might enhance breastfeeding rates, especially the maintenance of breastfeeding.
However there is already a financial incentive – infant formula milk is expensive – and it may be more likely that there are other barriers. But qualitative research can examine whether it is acceptable to those involved and trials can measure whether it is effective.
It is clear we also need a public conversation about whether this type of intervention is acceptable to society. As a scientist, I’d like that discussion to be informed by evidence of whether it actually works and its cost-effectiveness.
Oxford, UK
<i>The editor writes:</i>
• Turn to page 29 to read an interview with Mary Renfrew, the architect of the vouchers-for-breastfeeding study.
Death row
The US state of Ohio plans to execute a murderer with an untested combination of drugs (2 November, p 7). In contrast, you reported a humane method of rendering chickens irreversibly unconscious before slaughter in an altitude chamber in Arkansas (9 November, p 14).
It makes you wonder, is Arkansas more humane with their chickens than Ohio is with their death row inmates?
Byron Bay, New South Wales, Australia
Death row
I read of the crisis in the US penal system arising from the difficulty of obtaining supplies for lethal injections. Although no advocate of the death penalty, I am appalled by the inability to consider readily available morphine, presumably because of the risk that a criminal might die with a smile.
London, UK
Dump down under
Your report on the search for a solution to nuclear waste cited the Australian government’s refusal in 1999 to accept foreign nuclear waste (2 November, p 42). However, we have had several changes of government since, and, as explained in your article, there are now more ways of encapsulating nuclear waste for storage than by vitrification, the main method at the time.
As reported too, Australia is not only the most favourable country for storage in terms of political and economic stability, but it has several sites that are among the most geologically stable. Indeed, some in the outback are uranium mines. In non-populated areas and near a railway, these must be regarded as the best sites in the world for waste repositories.
The money earned from storing foreign waste would help to maintain Australia’s economic stability long after its coal and iron mining booms have ended.
Linden Park, South Australia
Historic health
Emma Young dates the oldest known tumour in the human ancestral line – a fibrous dysplastic neoplasm in a Neanderthal rib bone – to 120,000 years ago (9 November, p 36). There is, however, evidence for a much older human tumour.
In 2003, a German group described a meningioma in the Steinheim man (). The skull, dug up in Steinheim, southern Germany in 1933, is said to be a transitional form of Homo heidelbergensis to Neanderthal, 300,000 to 250,000 years old.
Mauer, Germany
Historic health
In her look at the prevalence of “modern” diseases in ancient populations, Young included researchers who speculate on the extent of disorders such as autism. I’d like to add my own speculation. It seems possible that those with Asperger’s syndrome could have proved crucial to the rise of monastic life in earlier eras.
Such religious retreats would have provided a place for anyone who had difficulty with social contact and had a taste for detailed study.
The rigid schedule and structure of such life would also have suited them well.
West Launceston, Tasmania, Australia
Play's the thing
David Whitebread and Sue Bingham’s article on the school starting age in England was both interesting and concerning (16 November, p 28).
I suspect I am not alone in thinking that it warrants a full exploration of the research and discussion of practical measures that parents of young children in this country can take to mitigate the detrimental effects of too much formality at a young age, or even to avoid them completely.
Upper Cambourne, Cambridgeshire, UK
Play's the thing
In Jonathon Keats’s review of Play, Playfulness, Creativity and Innovation by Patrick Bateson and Paul Martin (7 September, p 44), he mentions a 2006 study involving 10 and 11-year-old children in a play-based art class, whose originality, fluency and flexibility increased compared with those in a control group.
Apparently in Finland, children do nothing but play until they start compulsory schooling at age seven. I wonder if this has anything to do with the fact that since 2000, Finland has consistently featured at or near the top of international league tables for educational performance.
Halifax, Nova Scotia, Canada
Quantum catch
Geoff Stanley writes in his letter that “superposition of quantum states is only determined by observation… (and this may be the) ultimate example of top-down causation” (12 October, p 31). This is offered as an example of the macroscopic world impinging on the microscopic.
This would be true only if the “decision” to observe is itself not produced by a prior combination of microscopic states. I don’t think our knowledge of consciousness – as it stands today – can shed any light on this.
Chandigarh, India
Life's lottery
Letter writer Jörg Michael says it is “widely accepted” that people who come into large sums of money lose it all within a few years. He cites lottery winners as a model for bad decision-making causing poverty (26 October, p 33). This wrong conclusion derives from choosing an inappropriate sample population.
Lottery winners are hardly a statistically significant or an unbiased population, nor are they inherently meaningfully poor. In fact, very poor people given even small absolute sums of money, which represent previously inaccessibly large amounts for them, generally get an immense economic benefit.
Maybe the bad decision is to waste money gambling on a lottery, an option the abjectly poor can never take.
Griesheim, Germany
Squaring the circle
Chris Rogers writes to explain that he, as an atheist, squares moral obligation with a wholly materialistic universe by ethics, compassion and self-respect (9 November, p 31).
This led me to wonder how atheists square ethics, compassion and self-respect with a wholly materialist universe. Now I’m concerned that I may be attempting to square a circular argument.
Binningen, Switzerland
Take the stairs
Your article on a slowdown in the increase in global emissions of greenhouse gases cites energy efficiency as a key reason (9 November, p 6). It lists fuel savings in factories, more fuel-efficient trucks and the growing adoption of low-energy light bulbs as examples.
Sweeping away unnecessary building regulations could help further, such as mandatory motorised garage doors in parts of Australia, tall office blocks where stair use is banned in favour of lifts, obligatory powered waste disposal units in homes in Minnesota and Maryland, US. In buildings everywhere we see excessive use of electricity.
Klemzig, South Australia
Three-legged race
You report that parents can now choose their baby’s traits by selecting eggs or sperm with certain DNA sequences (12 October, p 6). It will not be long before gold medals will be won at the Olympics by competitors who have body features suspiciously well suited to their sport.
The ancient games lasted more than 1000 years, the modern ones may last less than 200.
Eastwood, New South Wales, Australia
Cashing in
Feedback asks: “As for Arctic melting being beneficial… to whom?” (2 November). Well come on, surely ’tis plain and obvious. Without all that inconvenient ice in the way, cable-laying ships can put in place a direct optical link along the between New York and Tokyo, shaving precious microseconds off arbitrage deals on financial markets. To a select few traders, it could be worth billions.
Cracoe, North Yorkshire, UK