Termite history
The use of termites as indicators of mineral deposits has a longer history than Beth Geiger mentions (30 June, p 35). Maps of Rhodesia (now Zimbabwe), about 60 kilometres north of Que Que (now Kwe Kwe) show a gold mine named Termite founded by the Black brothers in the 1920s. They established the presence of gold by collecting a mass of termites from a mound, rendering them down and sampling the residue. They used the same methods to establish the nearby Leopard, Leopardess and Lion mines.
Not scared, just insecure
Dorothy Rowe links attention deficit hyperactivity disorder symptoms with a child’s fear of adults (16 June, p 24). Surely a more likely explanation of these symptoms is stress and anxiety caused by insecurity.
We know that the major problem children say they face daily is bullying, and we know that the bully is usually using this behaviour to cope with his or her own insecurity. The important issue is why children now suffer more from insecurity. The answer is not that children are now more insecure than previous generations, but that the support is often lacking to cope with the insecurity, both from parents and from the neighbourhood.
A quarter of children in the UK are in broken families. Even where the family relationship is strong, the parents are often themselves insecure in their jobs or facing severe financial pressure, and this insecurity transfers to the children.
Increased mobility and migration mean that the support that can be offered by an extended family is often lacking. The grandparents may now be thousands of miles away, while neighbours may come from a different culture.
In short, the old cosy certainties have gone. Add to this insecurity the taste for high-fat, high-sugar foods, which are proven to cause many of the symptoms linked to ADHD, and British society is on a roller coaster.
Either live with the consequences or jump off, as thousands of families are doing every year, heading for my corner of Europe.
Cloning people
Hugh McLachlan’s discussion of arguments against human cloning is mostly perceptive and accurate (21 July, p 20). It is not the case, however, that cloning poses only “risks that we accept in other methods of reproduction”.
All other methods of assisted reproduction merely facilitate the union of sperm and egg, and the creation of a new genome. Cloning does not involve conception: it is replication rather than reproduction. IVF allows us to circumvent fertility problems; cloning is an entirely new method of creating children.
It is obviously true that it is better to be born a clone than never to exist. This does not mean that there are not good utilitarian reasons for prohibiting cloning.
If a man and woman are infertile and decide to clone themselves to create a family, their children (if they have one boy and one girl) will have no genes in common, and will each greatly resemble one of their parents on reaching adulthood. Even assuming that these clones do not find each other attractive (as their parents presumably did), this would create a very strange family dynamic.
Cloning should remain illegal because the possible consequences of permitting the practice outweigh the marginal benefit that it would bring to a very few infertile couples. People seek fertility treatment because they want to create babies together, not because they want to raise their identical twins as children.
Sick at heart
Jim Giles’s review of Sicko unfortunately misses the real point at the heart of this film (14 July, p 49). Why is a nation like the US, which claims to be the world leader in decency and democracy, so incredibly and systematically cruel to its most disadvantaged citizens?
Medical insurance and healthcare are just the tip of the iceberg of this country’s inward-directed cruelty towards, and hatred of, the unfortunate.
For example, the US judicial system devotes much effort to the persecution of the poor, who lack the means of legal defence, through selective enforcement of invasive laws that criminalise insignificant actions. In this way it provides a mechanism for racial and economic discrimination.
Reviewers of the film in the US have failed to note this major theme. Instead they have become caught up in the film’s healthcare sideshow, and have missed this broader and more painful critique of our culture.
From Ann Logan
Jim Giles refers to Moore’s previous documentaries such as Fahrenheit 9/11. The US administration hated that film, and called it “scurrilous”. If the film was full of “half-truths” as Giles argues, why was Moore not sued? Moore lists all the research sources for the film on his website ().
The question Giles asks does remain important: can a film such as Sicko lead to real change? Let’s hope that it can, despite the half-truths already being told about it.
Blue Hill, Maine, US
From Yadviga Halsey
Can Jim Giles enumerate for us the half-truths of Michael Moore? Here I am in the US, having been conversant with our so-called healthcare system for a long time, and way curious now to hear about these half-truths, which I did not notice when I saw the film.
Seattle, Washington, US
Jim Giles writes:
鈥� The most obvious half-truths were the slanted depictions of the healthcare systems in the UK, France and Cuba. The British NHS can be great, but waiting lists are often long and access to certain drugs can depend on where a patient lives. France’s system is indeed highly rated, but Moore did not mention the very high taxes there. Cuba’s public health is far above what would be expected for a country with limited resources and suffering the consequences of the US trade embargo, but it also restricts access to certain drugs and technologies.
Four legs good
A man’s bipedal gait is 75 per cent more economical than that of a knuckle-walking chimpanzee, “supporting the idea that bipedalism evolved to allow our ancestors to move around more efficiently” (21 July, p 14). Really? Should we therefore conclude that knuckle-walking evolved to allow the chimp’s ancestors to move around less efficiently?
The comparison between chimps’ and humans’ performance on a treadmill is meaningless. We move around efficiently now, after 5 or 6 million years of progressively restructuring our legs, feet, spines, skulls, and muscular and vascular anatomy to facilitate doing so. For our ancestors bipedalism would not have been more efficient.
In 1973 Richard Taylor and V. J. Rowntree , either on two legs or on four legs as required, and measured the amount of oxygen consumed. It was exactly the same when the animals ran on two legs as when they ran on four.
Sunshade safety
All alternatives to cutting carbon emissions to reduce global warming carry risks, but the methods reviewed by David Chandler seem particularly unfavourable (21 July, p 42). The simplest and cheapest method is to cover up to 10 per cent of the ocean surface with a material that has the optical properties of snow. This would reflect nearly 90 per cent of the solar radiation falling on it, as well as radiating as much heat as is currently radiated from that area of ocean, if not more.
The required properties could probably be achieved by treating conventional polymers to make this “artificial snow”. The necessary production capacity already exists, if we are prepared to forgo excessive packaging on our goods for a year or so. The cooling effect can be dramatic, as described in the section on modelling the effect of snow cover on my website .
Whatever method is chosen, something will inevitably go wrong. The risks with sulphur dioxide 鈥� which is a greenhouse gas and a powerful source of acid rain 鈥� are obvious. The chances of correcting the effect of tonnes of pico-satellites in space are small. A reflective ocean blanket, by contrast, would be relatively easy to adjust.
There is a further disadvantage of the high-tech shading methods. The technology will be controlled by the richest, most powerful country at the time, which will, in effect, control the climate of the whole planet. Less influential countries may be unhappy with the climate that they get. A relatively low-tech solution would permit a genuine negotiation over climate.
Boycott 鈥� or not
The letter from Hilda Meers (30 June, p 22) contains some mistakes. Universities and colleges in Israel do not have military checkpoints at the gate. They have civilian security guards, like the guards at the entrance to restaurants, supermarkets and kindergartens. These are similar to airport security and are there for precisely the same reason.
Secondly, although I have been in Israeli academic circles for many years, I do not recall any incidents of college students being imprisoned for their choice of reading material. As a college librarian I would certainly have heard of this.
Lastly, as a practising Orthodox Jew, I was not aware that Zionism, (the desire of Jews to live in a Jewish country located where the Jewish Bible and tradition place it) was not inherent to Judaism.
Drought doubt
A mere month after Rachel Nowak’s article emotively headed “The continent that ran dry” and your editorial (16 June, p 8 and p 5) the drought that gripped south-eastern Australia from 2001 to 2006 broke with a vengeance. There was widespread flooding in eastern parts of the state of Victoria.
I have been studying water management at a large mine site in central New South Wales, where the average annual rainfall over the 150 years up to 1999 for which there are records was exceeded in the first six months of 2007. Farmers are rejoicing because all indicators suggest that agricultural production in eastern Australia for 2007 will be the highest on record. So much for the dire warnings that this was a deep greenhouse-driven drought that would not break for at least decades to come and that agricultural production in eastern Australia would never recover to pre-greenhouse levels.
It is interesting that 2007 marks not only the collapse of the El Ni帽o conditions that generally applied from 2001, but also entry into the final quarter of the approximately 22-year Hale cycle of solar activity, in which annual rainfall has generally recovered to average levels or higher.
It is also relevant that a recent study suggests that precipitation and total atmospheric water have increased at about the same rate over the past two decades. This runs counter to the predictions of global climate models that global precipitation would only increase by 1 to 3 per cent per degree of surface warming while the total amount of water in the atmosphere would increase by 7 per cent per degree.
Oil's well
I have to take issue with the statement that oil production will start to decline after 2030 (7 July, p 28). For all of the time I have worked in the petroleum industry (nearly 60 years), the pundits have predicted the oil would run out in 20 to 30 years.
The earlier estimates have now been proved grossly inaccurate. Why? Because they were based on the technology available at the time. In the early 1950s no one dreamed of producing oil from the North Sea or other deep waters, still less from Arctic lands or seas. Economic processing of highly viscous crude oils like some now produced in Venezuela was similarly improbable. The same applies to the Athabasca tar sands in Canada.
There is no doubt that petroleum is a finite resource, but at present I see little sign that the progress of technology in finding, producing and processing it is slowing down. I would therefore be prepared to take on a bet with anyone that the prediction in the article is a serious underestimate. Unfortunately, it would up to my heirs to collect on the bet.
Laying down the laws
I am afraid Paul Davies has failed in laying down the laws of his own approach to flexi-laws in physics (30 June, p 30). Why would he use the term “law” for whatever is above the quantum domain, and “rule” for whatever is within it? Is there a difference between the two terms? If yes (as Davies seems to imply) he still has to tell us: how did the rules of quantum physics arise? Otherwise the solution he proposes to the Goldilocks enigma or “anthropic principle” is that the laws of nature are there because they obey quantum rules. How then, were those rules laid down?
Pragmatic non-realists
Eric Van implies that quantum non-realists are chasing down some elusive goal (21 July, p 23). On the contrary.
For many non-realists the only “reality” behind what we observe is that we (and our instruments) cannot actually experience any reality behind what we observe. And so we attend to modelling what we observe instead. This is hardly an elusive goal.
An unsurprise
Your discussion of nanobacteria and their possible link with calcification in the body is exciting (23 June, p 38). It should not have come as a surprise, however, that tetracycline has an effect on calcification: it a well-known calcium chelator.
For the record
鈥� A letter, “Ocean of doubt”, implied that deposits of calcium carbonate, from the shells of plankton, on shallow sea floors could help sequester carbon dioxide (28 July, p 22). In fact, the formation of calcium carbonate releases CO2 into seawater. Only the formation of sediments containing organic matter removes carbon dioxide.
If program, then…
I have a bit of an issue with some of the definitions of “programmable” Noel Sharkey uses in discussing the programmable robot of ancient Greece (7 July, p 32). He confuses “protocol” with “programming”.
A sequence of instructions is not a program, it’s just a protocol. Just because one can change the protocol sequence doesn’t make something programmable in any useful sense of the word. A programmable machine needs to follow a protocol but in addition it must have runtime flow control. That is, program = protocol + flow-control.
Noel Sharkey writes:
鈥� In the historical context of the article I used the term “simple programming language” in a very general sense to mean a set of coded instructions that enables a machine, especially a computer, to perform a desired sequence of operations. In the context of modern computer science we do discuss and debate the formal requirements for what is and what is not a programming language.
It is also possible to make a case that the instructions for Hero’s robot conform to a more formal definition of a programming language that includes flow control. On an abstract analysis, there are conditionals in the language (at least implicitly), for example if peg then reverse the direction of movement or, at a stretch, while left axle paused, do turn robot to right. Using modern computing terminology, all these decisions were fixed at “compile time” 鈥� when the “code” of the pegs was generated. If Hero had used some sort of feedback control such as a bump sensor, which could have been possible, then we could have had a type of runtime flow control.
The key issue for me here is that the device is reprogrammable and could support a very large number of different behaviours. The surprising thing was that this type of machine programming was going on as early as the first century AD.
Colourful language
The introduction to your interview with linguist Annie Mollard-Desfour (30 June, p 44), after mentioning Berlin and Kay’s work on basic colour vocabulary, adds that Mollard-Desfour “too is convinced that colour perception is culturally defined”. This implies that Berlin and Kay themselves emphasised cultural determination of basic colour vocabulary.
I believe they saw their work as evidence against the common idea that different cultures freely divide up the spectrum in different ways, and as evidence for a universal pattern of historical development of colour vocabulary. Berlin and Kay suggest that all languages begin with a binary division of the colour field into cool/dark and warm/light, then develop a term for red, then one for either blue or green (“grue”), followed by green or blue (whichever was not carved out of the colour field at the earlier stage), and so on.
From Brett Reynolds
Annie Mollard-Desfour makes the claim that to a Japanese person the brightness of a colour is more important than its hue and that the Japanese language has a large number of words for white.
I’m afraid that after spending ten years in Japan I had never noticed any of this, so I put it to my Japanese wife. She was as perplexed as me. We had a look in the Kenkyusha New English-Japanese Dictionary, 5th edition, and could find only a single translation for the colour white. Oh, there were words like “cream” and compounds like “snow white”, but only one word for “white”.
This, of course, brings to mind the great Eskimo vocabulary hoax (i.e., Eskimos have umpteen words for snow) and the endless “snowclones” that people love to rehearse in exoticising a language or a people.
Since Mollard-Desfour is a linguist and a lexicographer, I’m sure she’s not simply making this stuff up. I, therefore, look forward to seeing the examples or citations that my wife and I must have overlooked.
Caledon, Ontario, Canada
Annie Mollard-Desfour writes:
鈥� The importance accorded in Japanese culture to matte-gloss and brightness distinctions is mentioned in numerous linguistics papers dealing with the cultural aspects of language and of naming 鈥� as are these features of Inuit language. True, some linguists currently propose that we need to distinguish terms for an abstract “true white”, that does not refer to any particular instance of “whiteness”, from those that refer to materials such as snow. Japanese certainly has terms for “white in general” and others linked to particular instances of whiteness: and .
It remains the case that the lexicon of colours is difficult to understand and to translate, because the parameters used may be fundamentally different. Hence the controversies: what words translate the French blanc 鈥� and are the whites of snow or other bearers of whiteness true colour terms?
Asteroid deflection
While it is disturbing that someone has chosen to avoid scrutiny of NASA’s asteroid deflection options by making them classified, I disagree with Clark Chapman’s suggestion of using a spaceship as a “gravity tractor” to deflect an asteroid (7 July, p 19). Fashionable though the “gravity tractor” idea may be with some scientists, it is poorly thought out and fundamentally flawed.
To keep a “gravity tractor” spaceship from falling onto an asteroid, the spaceship’s thrusters would have to be pointing towards the asteroid. Unless the thrusters were further apart than the width of the asteroid, their reaction mass would hit the asteroid, pushing it harder than it was being pulled by the gravity of the ship, resulting in a net acceleration in the opposite direction to the pull of the ship’s gravity.
Additionally, the “gravity tractor” approach involves a tremendous fuel cost to get a massive spaceship to reach and match orbit with the asteroid, and requires considerable time first to position the spaceship and then to achieve the necessary trajectory change in the asteroid.
A more effective option would be a controlled bombardment of the asteroid with numerous small explosive charges, effectively turning part of the asteroid’s mass into reaction mass and substantially leveraging the payload of the delivery vehicle. By calibrating the size and rate of the explosions to the asteroid’s properties the risk of break-up could be minimised.
As for the nuclear option, the sad truth is that while we may have decades of warning of an impending asteroid impact, by the time the politicians finish arguing we may not have much time left to implement a deflection plan, so we should have fast-acting options available. Here nuclear explosions have a huge potential advantage, offering a thrust-to mass-ratio up to 10,000 times that of other options, regardless of whether the thrust is used to deflect the asteroid from the Earth itself or from a critical “keyhole” through which it would have to pass to threaten the Earth later.
What we really need is serious public discussion, computer modelling and other analysis of the various proposed asteroid defence options, to determine which options are viable and which aren’t. For example, only computer modelling is likely to distinguish between a disastrous option that causes an asteroid to break up and still mostly hit the Earth, and a more acceptable one that causes a break-up with most or all fragments missing the Earth.
Clark Chapman writes:
鈥� though there wasn’t space in my comment to describe the various deflection technologies, but these things have in fact been thought about.
The thrusters on the gravity tractor would be canted at about a 45-degree angle, so that their thrust misses the asteroid, yet provides the balance required. (It would be a “fatal flaw” and remarkably stupid to do otherwise, for the reason Andrew Hicks mentions.) The gravity tractor that has been discussed need not be massive. The mass of an ordinary deep-space spacecraft is sufficient to move a very small near-Earth object away from the Earth, or an NEO of almost any size away from a keyhole.
As for his preferred option of using a series of explosive charges, they don’t need to be explosive at all. Simply colliding with the asteroid at high velocity provides plenty of wallop. This, indeed, would be the way to deal with cases requiring more momentum than a gravity tractor can provide.
Any method that requires interaction with the surface 鈥� whether those “kinetic impactors”, nuclear blasts, or almost any other approach besides the gravity tractor 鈥� has a lot of uncertainties about how the asteroid will respond. It is not simple like billiard balls. As the Deep Impact mission showed when it fired a projectile into a comet, there can be an enormous blow-back of ejecta, providing additional momentum. You can’t calculate in a computer how much blow-back there will be (or even spallation of a piece off the opposite side of the body) without knowing a lot about what the body is made of, its internal structure, and so on.
That’s the beauty of the gravity tractor. The amount of acceleration is precisely known and continuously measured during the drawn-out deflection phase. Unfortunately, there are cases for which the gravity tractor won’t be powerful enough. The good news, however, is that small NEOs with long warning times are the cases we are most likely to face, not the big ones with short warning times that would have to be dealt with by kinetic impactors or even nukes.