Sense about size
Once again your pages mention PM10, the magic number that describes the notorious particles that must be removed at all cost (Technology, 29 April). Indeed they must, but should we not be considering the larger particulate as well?
Inspirable particles range in size from 0.01 to over 100, and tracheobronchial from 5 to 50 micrometres. Perhaps one should also contemplate the ultimate size of larger particles after they have been subjected to a range of climatic forces. It his not impossible that some particulates emitted at 50 micrometres or larger break down to form the source of tomorrow’s respirable particulate.
Maybe if we start to consider PM100 seriously, we will end up with a lot less PM10.
Tiger tally
In your report on India’s tigers, (This Week, 13 May), you stated that the World Conservation Union (IUCN) has put the number of tigers in India at around 3000, and that it predicted that the tiger could be extinct in India by the end of the century.
In a written statement at a press conference in Delhi on 30 March I said: “The tiger will be virtually extinct in the wild by 1999 unless India and the other range states declare open war on poachers and illegal traders and throw all the resources required into the battle. Some scattered individuals will remain and produce some young for a decade or two in the 21st century, but, in fact, we shall have seen the end of the tiger.”
As to the number of tigers in India, the official census in 1993 put the figure at 3750. An analysis of the reports from the States and tiger reserves by the Vice Chairman (Asia) of the Cat Specialist Group, Valmik Thapar, who is a non-official member of the Project Tiger Steering Committee suggested that the figure could be as low as 2750.
Unfortunately, more than half India’s tigers are without active protection because they are not in the 23 special tiger reserves and some other well-maintained national parks and sanctuaries. Well-organised poaching and illegal trade to provide tiger bones for Chinese medical systems is devastating tiger populations throughout the range.
Ullas Karanth is not carrying out a census; his project aims to obtain data on tiger density in a few representative areas of India.
Chocoholic rats
While the British Government and the chocolate industry wrangle over whether to spend a 拢4 million bonanza on genetic research into cocoa (This Week 13 May), such work continues on a shoestring.
About 30 per cent of the world’s chocolate is gobbled up by rats and squirrels before it is even harvested from the cacao tree. Self-funded scientists at the University of the West Indies in Trinidad have identified that rodents prefer to consume cocoa pods which are crunchy and thin-walled. The results, published in the tropical biology journal Biotropica, were a surprise, as most animals prefer soft fruit. Most fruit soften upon ripening, whereas cocoa pods become harder and hence more attractive to rodents
Identifying what squirrels like about eating chocolate has allowed the genetic selection of cacao trees immune to rodents. One particular clone has been found which is never touched by rats or squirrels. This appears to be related to a repellent odour not detectable to the human nose
Attempts to identify the chemical responsible for repelling rodents stumbled upon a novel antibiotic compound in the pods of a cocoa clone being used as a control. The compound appears to endow the tree with disease resistance to several fungal pathogens. If the chocolate industry is successful in securing the 拢4 million from the government for research, then attempts to identify the gene involved in the production of this antibiotic or the mysterious rodent repellent properties of some cocoa pods may benefit greatly.
Gripping problem
Ivor Watts questions a racing car’s ability to accelerate and decelerate at g levels in excess of unity (Letters 13 May). Your editorial comment attributes the achieved performance to aerodynamic down-force. While this is true, it only partly explains the phenomenon.
Current racing tyres have a “coefficient of friction” of 1.8 to 2.0. Of course this cannot be true coefficient of friction, and these levels of adhesion rely on envelopment of the micro-surface of the road and local bonding to the road, as well as classic friction.
The achieved “coefficient of friction” is strongly dependent on the structure of the road surface, the rubber compound and the tread temperature 鈥� optimally around 120 掳C. How to make a tyre grip the road is probably the key remaining black art of motor racing.
Not many galaxies
In “Big is beautiful in astronomy” (Review, 6 May), a typographical error of significant magnitude occurred. David Hughes asked the question: “Why are there only 109 galaxies?” The number in the question is really 109, that is, 10 to the power 9.
Lottery losses
In the light of R. L. Sinclair’s responses (Letters, 13 May) to my letter of 22 April, perhaps I should make it clear that I intended readers of my letter to draw the conclusion that you should not play the National Lottery. This is undoubtedly the best strategy for minimising your expected loss.
Marvel of maggots
With reference to the item in volving Sir Alexander Fleming (Feedback, 13 May), a Canadian who served in World War One told me this story: During the battle of Passchendaele, an allied soldier, injured and out of reach in no-man’s-land, called for help incessantly for (I forget how many) days 鈥� just take it that it was an abnormally long time. When he was brought in and examined, it was found that his multiple wounds were remarkably clean. This was put down to the quantities of maggots removed from his injuries.
After the war, my friend qualified as a medical practitioner and established himself in the Nova Scotia fishing port of Lunenburg. One summer’s day he was brought a sailor badly injured in the groin. The man had unfortunately been eight days getting home to port. The wound was already gangrenous and required surgery at the main hospital facility in Halifax, 68 miles distant by car. Before sending him off, the doctor paid a couple of lads to go down to the waterfront and fetch him a jar of maggots.
He contained the maggots around the wound with a contraption he rigged from plaster and bandages, complete with perforated cover. By the time the patient got to the hospital, the wound was clean.
The surgeons were outraged and filed a complaint with the medical board. It failed. My friend’s mode of treatment may have been unconventional but it had its pedigree in inadvertent experiment, as he explained, and no-one could argue with its efficacy.
You may guess the conclusion. It was that (as you report Sir Alexander Fleming’s opinion on the use of maggots) they had been an excellent idea, but their use was not advised in general practice.
Feedback thinks Sir Alexander Fleming was behind the times in considering maggots beneficial for wound healing. But the idea, like so many, has come full circle. In 1987 that illustrious journal New 杏吧原创 described a “Maggoty cure for injured soldiers” (Science, 6 August). In January 1995, wound specialist Ronald Sherman addressed a meeting of the European Tissue Repair Society on the use of maggots for wound healing. Zoologists at Oxford University are now breeding maggots for what is delicately called “bio-surgery”.
Chamber pot cheer
Whatever A. James might think of it (Letters, 29 April), Ralph Estling’s version of the ancient German creation myth certainly cheered me up no end. At last I know why the Universe is the way it is. What else can one expect of an improvised chamber pot created in a hurry by a drunken god?
Bog standard
Every house has at least one; its design little changed for almost two hundred years. The humble water closet sits there dripping with condensation, rotting the bathroom carpet, a forgotten victim of a stagnant technology. Now suddenly, we are threatened with the inconvenience of a new European Union imposition, the Euroloo, a potentially pungent design which lacks a U-bend.
The truth of the matter is that the traditional British loo is costing us dear. After each flush the cistern fills up with cold water which slowly warms up by absorbing energy from its surroundings. Placing a temperature sensor connected to a data logger in a family toilet for 24 hours in mid-March revealed a total temperature rise after flushes of 28.5 掳C. As the toilet cistern holds 11.3 kilograms of water this equates to an energy consumption of 0.4 kilowatt-hours per day. This calculation is on the conservative side as it ignores the water in the bowl, which will also absorb energy.
Assuming that this energy consumption is typical of the six winter months and that no energy is consumed in the six summer months, the annual energy consumption per toilet is 70 kilowatt-hours. At a typical cost of 3p per kilowatt-hour this amounts to 拢2.10 per toilet per year. Not a lot admittedly, but during the long life of a toilet this will add up to a significant amount. We must also consider that there must be at least 40 million toilets in this country consuming on average 600 megawatts of power.
We must not allow an ill-informed bureaucratic decision to rush us into a new standard design until the technology is thoroughly tried and tested. The new toilet must be odourless with improved insulation, quieter flushes and reduced water consumption.
Web wonder
Has anyone noted the anticipation of your “spiders on drugs” story (This Week, 29 April) in a 1968 sci-fi novel, Charles Harness’s The Ring of Ritornel? At one point the drugged hero’s blood is fed to a spider and the nature of the drug deduced from the resulting web pattern: it’s a mind-controlling “slave drug”, so naturally the spider ends up imprisoned in her own 3D web.
From the book: “A spider dosed with a little alcohol weaves a drunken web. If stimulated with caffeine, she will build one which is a model of engineering precision. With mushroom drugs, she builds one circular strand with a couple of spokes, then hangs in the centre, a spider god in a spider universe.”
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Compensation cost
If the cost of electricity generation, as Stuart Campbell writes (Letters, 13 May), is primarily a function of the discount rate and the amortisation rate, then it must be said that nuclear power is at present getting a handsome discount by being granted limited liability against the costs of a “maximum credible accident”.
The setting of compensation for nuclear accidents is ferociously complex, involving international law (since pollution crosses state boundaries), and delays of up to 30 years between the incident and the appearance of cancers caused by the accident. Factors to be covered include birth abnormalities, cancers, psychological trauma, environmental damage, loss of agricultural produce and land, loss of use of property, loss of profit and productivity, population evacuation and relocation, and the cost of cleanup operations. At least 12 estimates have been made of the cost of major nuclear accidents. None of then gives complete coverage of all the factors, and the results vary from $2 billion to $60 trillion.
The revenue in 1990 for OECD nuclear electricity sales was $109 billion, so that a 10 per cent levy to cover accident liability would yield $10 billion per year, which over 10 years would build up to a kitty of more than $100 billion. This levy would give a modest start to the process of instituting full compensation to victims of any future nuclear accidents. It should be set up without delay, and the figure adjusted as and when more accurate assessments of the damage emerge. Not to do so would be to violate the polluter pays principle and artificially to keep low the market price of nuclear energy.
For nuclear power to remain uninsured would be to impose burdens on the health services and general tax budget in the event of an accident, effectively forcing them to subsidise nuclear power. And we can be sure that at this time of privatisation of nuclear power, nobody would want that to happen.
Weather below
The study of weather is concerned with the transfer of heat and changes of phase between gaseous, liquid and solid water, and the lower boundary of the region usually considered by the science of meteorology is the solid-gas interface on the continents and the liquid-gas interface over the oceans.
The study of plate tectonics is concerned with similar interactions in the layer directly below this, the main differences being that only the solid and liquid states are involved, that changes between the phases are rarely seen, and that the timescales involved are larger by several orders of magnitude.
As a nonparticipant in both sciences, I observe that this distinction is arbitrary. It is well-known that the eruption of volcanoes can affect climate, that upwelling in the ocean depths heats the oceans, and that the drift of continents has a largescale effect on the weather. Why not study the weather right down to the earth’s core?
Until recently, practitioners of both studies were grateful for the distinction. It kept the calculations, already enormously complex, to a reasonable magnitude. It seems to me that with the ever-increasing capacity and speed of computers, it might be possible to study and model the larger system comprising everything from the mantle outwards. This might give valuable insights into both sciences and even give rise to discoveries.
Of course it is dangerous for a layman to speculate like this. For all I know, the combined science which I am proposing already exists, has a name, and is the subject of numerous Phd theses and ongoing studies. On the other hand, it may just be that, as so often happens, the technology has only just arrived at the point where a new idea is realisable. It would be interesting to hear the comments of experts on both sides of the boundary.
Fuel fairness
I was delighted with Judith Hanna’s article proposing a world-wide scheme of Fossil Fuel Rights for all adults (Forum, 29 April).
Calculations I have published in Energy World indicate that this FFR will have to come down to a figure of the order of 0.33 tonnes of oil equivalent (TOE) per capita per annum, before humanity can reach equilibrium with the ecosphere. This is based on the following assumptions:
1. The 1989 total world consumption of fossil carbon fuels (about 7200 million TOE) must be reduced to one-third before we can reach a level of atmospheric CO2 which can be absorbed by natural processes.
2. Such a steady state requires, as Hanna agrees, “fair dos for everyone”.
3. The world population has levelled out at between 7000 and 8000 million.
To this ration of fossil fuel as much renewable energy (especially solar, wind, microhydro and biofuels) as can be produced can be added. Nuclear fission cannot be regarded as renewable because it leaves an ever-growing legacy of artificial radioactivity to our descendants.
During the period of nearly 60 years that I have been concerned with energy, I have seen only three brief periods when government policy was to save fuel, whereas the interest of the consumers is to satisfy their needs using as little energy from fuels as possible. The interest of our descendants is that we leave them a permanently sustainable technology.
Flipping extinction
For a long time it has been believed that the extinction of the dinosaurs was caused by the collision of the Earth with a giant meteorite or asteroid that crashed in the Yucatan area of Central America. Another possible cause would have been extensive violent volcanic activity in India as the Deccan Traps were created.
But there is another possible cause for the extinction of the dinosaurs. They could have died from intense radiation exposure caused by a flip of the Earth’s magnetic field. The magnetic field or magnetosphere protects our globe from fast moving particles spewed out by the Sun or other sources such as supernovas.
A flip of the magnetic field means a reversal of its polarity, the north magnetic pole moves into the southern hemisphere and the South Magnetic Pole into the northern hemisphere. In doing so the magnetic field goes right down until there is virtually no magnetic field any more (the most dangerous time for radiation) then slowly increases again with reversed polarity to its former strength.
Such a reversal could also have caused genetic mutation in some species and possibly created new ones. The only species on Earth protected to a certain degree would have been those living at the bottom of the seas.
Perhaps there is evidence of such a flip at the time of the extinction of the dinosaurs and maybe we are at the threshold of the next one.
Euro-emissions
Fred Pearce’s article “Costa del Carbon Dioxide” (6 May) may make good xenophobic journalistic copy, but its two central claims 鈥� that the European Union has agreed that Spanish carbon dioxide emissions should rise by 25 per cent and that this was accepted by the international community at Berlin in April 鈥� are both wrong.
When in 1990 the European Community declared its objective to stabilise total EC CO2 emissions, this was informed by national projections, including big increases projected by all the “cohesion” countries (Spain, Ireland, Portugal and Greece). The general principle that emission reductions from some of the richer and higher emitting states would offset increases from poorer members was quite properly accepted by all parties as the basis of EC stabilisation.
When the cohesion countries signed the Climate Convention at Rio in 1992, they did so explicitly under this EC “umbrella”. Nothing has changed between Rio and Berlin, except that national projections and goals were reported to the Berlin conference, by the countries themselves and collectively by the EU. This does not indicate acceptance of specific national figures, indeed the EU’s report said explicitly that more effort is needed.
Spain’s specific projection of a 25 per cent CO2 emission increase over 1990 levels was, and remains, absurdly high, but it was never formally “accepted” by other member states or by the EU. Rather than negotiate fair allocations, in 1990 the Commission chose to go down the path of trying to agree policy measures, such as the carbon tax. All these efforts have failed.
Your article, obsessed with its veiled anti-Spanish rhetoric, missed the most important point. With the Berlin conference having launched a new round of negotiations towards post-2000 commitments, surely the EU can no longer avoid the need to start negotiating seriously what does constitute a fair allocation of effort between member states 鈥� negotiations that must be founded on a strong, critical and comparable process of assessing the basis of member states’ emission projections and their related energy policies.
Fred Pearce writes: Michael Grubb is right only in the narrow legal sense that there is no formalised agreement to specific increases in Spanish emissions. The formal agreement is on burden-sharing, whose precise terms remain, as the article made clear informal. There is nonetheless a clear understanding, as ministers confirm.
At the final session of the Berlin meeting, the EU took the floor to explain that its members could only agree to the Berlin mandate under its “burden sharing” arrangements, and this was accepted by the meeting without demur. Berlin was the first opportunity at which parties to the convention could voice their acceptance of EU burden sharing. They certainly did not do it in Rio.