Replacing resources
The current technology-driven rush on tantalum, gallium, indium and other rare elements (26 May, p 34) brings to mind some earlier crises. One was the great thorium rush of 1892, which followed Carl Auer von Welsbach’s introduction of thorium dioxide-impregnated gas mantles the previous year. The price of thorium leapt tenfold in a few months. As gas mantles were replaced by incandescent bulbs, demand for thorium eased, and a shortage was averted.
This in turn was followed by a world shortage of the very rare element osmium, introduced in 1897 as a filament metal in early electric bulbs. The osmium shortage threatened to bring the infant incandescent-lamp industry to an end, until it became technically possible to use far more plentiful elements 鈥� tantalum and then tungsten 鈥� for filaments.
Another osmium crisis followed when, in the early years of the 20th century, German chemists Fritz Haber and Carl Bosch appropriated virtually the entire world supply for use as a catalyst in the synthetic ammonia process they were pioneering. When they found that iron (with a little molybdenum) was an equally good catalyst, osmium became available once again. Such shifting technologies may “release” some of the elements in critically short supply now.
From Peter McCarthy, Australasian Institute of Mining and Metallurgy
It seems that David Cohen has made the same fundamental mistake in estimating the Earth’s mineral resources that the Club of Rome made in its 1972 report Limits to Growth. Published estimates of mineral resources and ore reserves tell us something about the historical exploration effort, but very little about the actual contents of the Earth’s crust. For any mineral or metal, the resources discovered as a result of historical expenditure on exploration reflect commercial decisions in an environment of changing commodity prices. Most of the deposits defined and exploited in the past were discovered from surface outcrops, whereas future mineral production will come from deeper deposits discovered using remote-sensing technologies yet to be developed.
Carlton South, Victoria, Australia
Let them eat yellowcake
You report that the US is planning 30 new nuclear power stations and the UK 10 (26 May, p 6). Is it coincidence that in the same issue you report that at today’s rate of use, uranium deposits will be exhausted in 59 years (p 38)? What will these stations (and those planned by China, Russia and other EU countries) run on?
War in the air
You say that the International Crisis Group is planning to “start talking about whether to include [climate change] in its analyses” (2 June, p 12). We have been looking at climatic factors in the conflicts we cover for some time, but we find the suggestion of a “link between climate change and conflict” overly simplistic. We certainly have no intention of adding rainfall measurements to our regular assessments of conflicts worldwide, which are made instead on the basis of our field analysts’ extensive interviews with the warring parties and other relevant agents.
Crisis Group has no relationship with Marc Levy, who is researching drought and conflict, though it is entirely possible that he uses our freely available reports and conflict analyses as he conducts his studies. We particularly reject any association with the idea that the crisis in Darfur is a “climate change war”.
The humanitarian disaster in Darfur results primarily from the Sudanese government’s extremely brutal counter-insurgency campaign, which has used proxy militias to carry out mass atrocities, resulting in over 200,000 deaths and 2.5 million displaced. Look not to the cloudless skies but to Khartoum.
Pain mechanism
The novel class of pH-dependent NMDA antagonists for pain relief is very interesting (2 June, p 11). You suggest that they may help a subset of patients who do not respond well to treatment with gabapentin. Although gabapentin was originally made to mimic the GABA neurotransmitter, it is now widely believed that its clinical efficacy is a result of modulating voltage-gated calcium channels (namely a2d1 subunits), rather than enhancing the GABA system as stated in your article.
Though there is some controversy over gabapentin’s exact mode of action, pharmacological evidence suggests that it does not bind to members of the GABA receptor family nor can its actions be blocked with GABA antagonists. Furthermore, the reduction of a2d1 activity inhibits the release of multiple neurotransmitters (rather than just GABA) within the central nervous system, attenuating the abnormal hyperexcitability observed in neuronal networks in many disorders or conditions, including pain, anxiety and epilepsy.
Selling drugs
I feel that Nic Oatridge’s defence of medical marketing may indicate that he has led a sheltered life in this respect (9 June, p 26). I worked for 17 years in an environment in which pharmaceutical reps vied with each other to obtain the attentions of senior medical staff by means of gifts.
Examples included hard-to-get tickets to rugby matches, Christmas dinners for departments and expenses-paid trips for senior medical staff and partners on the Orient Express. The rep who didn’t find the magic key didn’t get the ear of the medical professional easily.
Crash test dummy?
The fact that Rusty Haight has managed to avoid serious injury in his exhibition crashes has virtually nothing to do with the injury potential of the crash (5 May, p 50). It is due rather to his physical hardiness (some might say foolhardiness) and inclination to take risks in the way he makes his livelihood. While very high-energy collisions almost invariably produce injury and death, the risk of injury in lower-speed collisions of the kind that Haight routinely participates in depends on gender, age and individual frailty far more than on the change in speed in the collision.
Haight’s willingness to repeatedly expose himself to low and moderate-speed collisions is no more relevant to the potential for injury in a crash than is the carefully planned jump from a building by a movie stuntman to the risk from an accidental fall.
Adopt the position…
Feedback’s insurance expert is being honest about the “brace” position to some extent, but also a bit facetious (19 May). If a passenger’s head is waving around like a tree in a gale, upon impact it will whack into the seat in front at high speed, depending upon how quickly the aircraft decelerates. Braced against the seat in front, the head will suffer no greater deceleration than the rest of the body. Meanwhile, the arms around the head protect it from loose objects. An iPod travelling at 250 kilometres per hour does significant damage to the head; it might break an arm, but that can be mended.
In short, the brace position gives passengers the best possible chance of remaining conscious, which is vital, because after the impact their troubles are not over. Rapid evacuation of the wreck is imperative.
Not too long ago, an Italian aircraft ran out of fuel and ditched in the Mediterranean. Most of the passengers survived. Some who did not had misguidedly undone their seat belts, supposing that this would help them to get out more quickly; bad decision.
From Frank Cross
Things are worse than Feedback thinks. As a trauma surgeon, it is my professional view that passengers are encouraged to adopt the brace position so that their cervical vertebrae snap cleanly on impact, thus killing them instantly and painlessly, and sparing them the agony of burning to death in the subsequent fire.
Cabin crew sit with their backs to the direction of travel, thus sparing them the neck fracture, and also right next to the exits.
The military put a slightly higher price on their air passengers’ lives: all seats on military aircraft face towards the rear of the aircraft.
London, UK
For the record
鈥� We said that Ralf Sch眉tzhold’s team could steal the thunder from the Large Hadron Collider (LHC) with a table-top device that mimics conditions in the early universe (9 June, p 11). We omitted to mention that Sch眉tzhold says, “This is only a simulation… The LHC and other accelerators will give us the real thing.”
Replacing resources
David Cohen paints a pessimistic picture of the world’s remaining resources of a number of industrially important metals such as platinum, gallium and indium (26 May, p 34). However, the article did not explore sufficiently the possibility of exploiting the single largest resource of a wide range of industrially valuable metals 鈥� the sea.
For example, you gave world resources of copper as 937 million tonnes, yet there are around 1350 million tonnes in the sea; for gold the figures are 89,700 tonnes and 1.8 million tonnes in the sea; for indium 6000 tonnes and 9000 million tonnes; for uranium 3.3 million tonnes and 1350 million tonnes.
About 30 to 40 years ago a number of papers were published that examined the possibility of recovering metals from the sea, using ion-exchange technology. The proposal was that barrages, such as one across the UK’s Severn estuary, could incorporate huge banks of selective ion-exchangers that would selectively remove gold, uranium and other metals from the seawater. This would have achieved two objectives: the generation of tidal power and the recovery of industrially valuable metals.
Perhaps now is the time to go back to the past and re-evaluate these ideas.
A is for avocado…
There may be a cultural explanation for the apparently surprising consistency in the colours of letters of the alphabet experienced by people with synaesthesia, at least by English-speaking Europeans and North Americans (19 May, p 48). Most people will have learned their alphabet in early life with a pictorial ABC linking each letter with a picture of a common item beginning with that letter in bright primary-school colours.
In addition, the subjects were almost certainly given a set of colours from which to choose, without mixing, thereby drastically reducing their choice: I understand that the human eye can distinguish between 20,000 different shades of green 鈥� how much choice did the subjects have?
I am fairly certain that when I was learning the alphabet, A was for a rosy red apple, F for a brown fox, I for black ink, and Z for a black-and-white Zebra. Checking the latest edition of my first abc (Dorling Kindersley, 2004), it sports a red apple on the cover, plus mostly what I remember inside. They have branched out a bit though: A is now for ant, ambulance, avocado, aeroplane, abacus, acorns, and apron, as well as apples.
Surely a true test of whether synaesthesia is driven by understanding would be to get people to colour in letters of an unknown alphabet, or symbols from an unknown discipline that are not linked to any early childhood experiences? A strong correlation in the colours chosen for the symbols of high-energy physics or Feynman diagrams by, say, students of medieval Russian horticulture would be surprising.
Climate confusion
Thank you for your interesting feature on global warming (19 May, p 34). I was surprised, however, that you paid only superficial attention to geological evidence. Numerous studies of the effects of glaciation on rocks show that ice ages have occurred on Earth about every 200 million years: 40, 260, 460, 630 and 850 million years ago.
It is surely more than a coincidence that this is the length of time it takes the solar system to orbit the galaxy. Is it then unthinkable that every 200 million years or so our sun passes through bands of dust or interstellar matter that reduce the radiation reaching Earth?
The presence of bands can be inferred from the variations in the intensity of the cold as represented by the four glacial and three interglacial periods of our present glaciation. Since these typically run for around 150,000 years, our current climatic observations can have no statistical significance whatsoever.
The editor writes:
鈥� We have reported on the idea of dust clouds: for example “Cosmic dust off the hook” (5 August 2006, p 17): Studies of ice cores show that there has been no change in the amount of cosmic dust reaching Earth for at least the past 30,000 years, during which time the climate has changed dramatically as the planet warmed after the last ice age. So whether or not cosmic dust altered the climate in the very distant past, it is not altering it now.
The surly bonds of earth
Before his first experience of weightlessness, cosmologist Stephen Hawking said that he wanted to encourage public interest in space exploration (5 May, p 4). With an ever-increasing risk of being wiped out on Earth, he argued that humans need to colonise space.
Apart from the fact that we need very large human populations and strong societies to pull off space travel (perhaps unlikely to still exist in the event of ecosystem collapses on Earth), does Hawking really believe that humans could sustain themselves in space? It seems to me that he underestimates immensely the extent to which our organism needs Earth: from the bacteria in our guts to the peace of mind that comes from strolls through earthly habitats; from the way that our developing bodies need normal gravity to the ways healthy and happy humans cannot do without the daily and seasonal cycles that our planet provides.
We are “just” part of the ecosystem Earth. Whatever happens to that system will affect us at all organisational levels conceivable. I think it is both very na茂ve and dangerous to think that we can escape our earthly spaceship; better daydream about keeping the ship intact.
Why water?
In his eagerness to promote other chemistries as potential host systems for life, Douglas Fox neglects specifically to mention the principal reason water is exceptional: the hydrogen bond. Terrestrial life takes full advantage of its low bonding energy and full reversibility to maximise system energy efficiency.
It means that DNA can easily zip and unzip, proteins can have stable structure and function, and myriad other low-energy life processes are possible without resorting to a full-strength covalent bond. What other chemistries offer such efficiency?
Adopt the position…
The bright-yellow life jackets are, as Feedback’s insurance expert says, not intended to act as flotation devices (19 May). They are there to make it easier for the recovery services to spot the bodies strewn across rough terrain.
I was once asked to put on a life jacket over central Germany, some 500 kilometres from the sea.
From David Mason
Mythbusters, a TV show produced in California, did a test of the “brace” position in simulated air crashes. They found it made a big difference in reducing injury to the head, neck and torso. It made no difference to the limbs. See
Ormond, Victoria, Australia
From Lawrence Millar
Yes, apparently the brace position does reduce injuries to limbs, but it also ensures that passengers will break their neck on impact, reducing the survival rate and therefore ensuring one less legal case against the airline from a direct survivor of the crash. This was confirmed by my lawyer friend who specialises in aeronautical law and represents some high-profile airlines.
London, UK