Climate cause and effect
I read with interest about what the IPCC “didn’t tell us” about climate change (10 February, p 7). I was amazed by the illogicality of the sceptics who claim that a large part of global warming is due to changes in solar radiation. They seem to argue that if it were not entirely our fault, we wouldn’t have to do very much about it.
Even if a large portion of warming is due to non-human causes, we will still be heading for disaster, and we are obliged to do whatever we can about it. Since we have no control over the sun’s radiation, but can control our carbon dioxide emissions, we may still be able offset any change in the sun’s radiation by reducing our atmospheric CO2 level. All it means is that we must reduce it even more if we have to compensate for the sun’s extra radiation as well.
People hoping to justify minimising any reduction in their CO2 emissions by shifting some of the blame to the sun may have shot themselves in the foot. They have made things worse for themselves, because their argument implies even more stringent targets.
Conserving carbon
Ian Jackson asks about carbon dioxide emissions from bush fires (27 January, p 20). I estimate that the 2003 conflagration in Victoria, Australia, released around 88 million tonnes of CO2 into the atmosphere in a few weeks. If we add to this 12 months’ deficit in photosynthesis due to the denuded forests, the number increases to around 120 million tonnes of CO2, or over twice the total CO2 emission from all forms of transport for the whole of Australia for a year. The ledger is still open for 2006.
The sad truth is that if we stop the official hand-wringing and adopt timely interventions, a lot of these fires could be stopped at their source.
From William Hughes-Games
Logging, if done correctly, could help defeat global warming. Pluck a mahogany tree out of the jungle and turn it into fine furniture or quality houses; every tonne of dry wood sequesters more than 1.5 tonnes of CO2. Light reaching the floor of the jungle starts a race for survival between seedlings, so the new trees produce high-quality, knot-free timber. Everything depends on leaving the jungle or forest intact and selectively removing trees here and there.
Clear-cutting doesn’t produce the same quality second-growth timber. And, of course, a fully mature forest does not remove CO2. It is carbon-neutral.
Waipara, New Zealand
The editor writes:
鈥� Of course, very little timber harvested is currently made into “fine furniture”. There’s the matter of timing, too: on a century timescale, growing and still-standing trees are a carbon sink. Equally, while a bush fire may be carbon-neutral on a timescale that includes the vegetation regrowing, it produces a surge of CO2 now.
Personal trauma
In considering post-traumatic stress disorder (PTSD), it seems to me to be questionable to compare the traumatic impact of events such as rape, physical attacks or distressing tours of duty against events like large-scale terrorist attacks or natural disasters (3 February, p 40). The attacks on 11 September 2001 and the 2004 Asian tsunami have reverberated in the affected societies’ consciousness for years after the event, with wide media coverage. The people affected will have exchanged thoughts and feelings. Both these features would surely reduce the prevalence of PTSD.
In contrast, after events that affect people on their own or in small groups there is less opportunity for communication of feelings. There is no exposure to the incident after it has happened, and the potential for feelings of isolation is greater.
Perhaps the disparities observed in the percentages of people who develop PTSD after traumatic events are, in part, due to the natures of the events.
From Pam Lunn
Towards the end of her article on post-trauma mental health issues Laura Spinney draws attention to the differing patterns of response between, say, 11 September 2001 or the London bombings of July 2005, and hurricane Katrina.
An attack in a public place is limited in time and space. The survivors go home, specifically to their own home, as well as to wider familiar neighbourhoods and networks.
Large-scale natural disasters, such as Katrina, are extensive in both time and space. There is no home to return to. There are no familiar neighbourhoods or networks to return to 鈥� these are precisely what has been destroyed. There is no “normality” into which the victims can reinsert themselves.
Kenilworth, Warwickshire, UK
Wait for clinical trials
Ralph Moss of states that dichloroacetate (DCA) has “never been tested in humans, only in cell lines and experimental animals” (3 February, p 20). But according to Environmental Health Perspectives (vol 106, supplement 4) “DCA toxicity is predicated mainly on data obtained in inbred rodent strains administered DCA at doses thousands of times higher than those to which humans are usually exposed. In these animals, chronic administration of DCA induces hepatotoxicity and neoplasia. Ironically, the DCA doses used in animal toxicology experiments are very similar to those used clinically for the chronic or acute treatment of several acquired or hereditary metabolic or cardiovascular diseases. As a medicinal, DCA is generally well tolerated… It remains to be determined whether important differences in its metabolism and toxicology exist in humans between environmentally and clinically relevant doses.”
I think we have to wait for clinical trials of DCA in people with cancer and not exaggerate a possible negative outcome beforehand.
Controlling hedgehogs
Hugh Warwick is right to feel annoyed that Scottish Natural Heritage ignored his own studies of translocated hedgehogs when advocating a cull of the population in the Hebrides (10 February, p 16). SNH also ignored several of my own published papers showing that translocated animals can cope well and do not suffer “slow and lingering deaths”.
An exemplary eradication of a mammal population was carried out in the 1980s, when coypu were removed from the UK. That operation was managed according to a population model that predicted the trapping effort needed to achieve likely end dates.
The SNH operation is not science-based but conducted on a “suck it and see” basis, a methodology that conservation managers should have left behind long ago. Clearly, eradication is not feasible with the present catching effort and will become even more difficult as numbers decline. Yet SNH has refused to reconsider its actions and has already spent 拢90,000 in one year on this cull, killing just 66 hedgehogs. It has no projected end date. This is public money spent doing what the public clearly do not want 鈥� killing hedgehogs that could be released alive somewhere else.
Supersize, no surprise
Certain participants in the Swedish overfeeding study showed apparent resistance to becoming “supersized” despite excess food intake (27 January, p 28). This should be no surprise.
A number of experiments with pairs of identical twins have reported that twins gain almost exactly as much weight as each other, though there are marked differences between pairs of twins. This suggests that genetics play a large role in determining responses to chronic overfeeding.
The same variability is seen in responses to weight-loss interventions through diet and/or exercise. Clearly, not every person who consumes excess calories will become obese, and conversely not every overweight person who diets and exercises will experience identical weight loss.
It seems that during past times of food scarcity, “thrifty genes” ensured survival. Unfortunately, these same genes now contribute to the development of obesity in our current “obesigenic” environment.
Brains aren't that simple
Douglas Fox in writing about “the mind chip” perpetrates the sort of hype that exists in artificial intelligence (AI) research (3 February, p 28). As a neuroscientist, I applaud Kwabena Boahen’s aim of understanding the brain 鈥� but to me the approach seems rather misguided.
It assumes that computation in the brain is supported only by chemical synaptic communication between neurons. This doctrine dominates both neuroscience and AI. It is now apparent, however, that cells of the glia 鈥� often thought of as the connective tissue of the nervous system 鈥� such as astrocytes also have roles in computation. Although we are still in the process of understanding how this works in concert with neuronal networks, the majority of AI research ignores it.
The ways in which glial cells signal (both with each other and with neurons) require different mechanisms from that of neuronal-neuronal communication. This fact is also ignored. There are also many coordinated structural changes that occur with both neuronal dendritic and glial processes that mediate complex communication.
Who says we're unique?
Adrian Barnett argues that humans are “unique” because “we are the only living member of our genus” (3 February, p 47). It was, of course, a human, Carolus Linnaeus, who invented the system of classification. As well as making sure that he himself was not in the same genus as his closest relatives, the other great apes, he worked out a system of “race” in which Europeans like himself were supposedly members of a superior race as well being a “unique” species.
Muscle power
Stephanie Pain describes the strength and stamina of trireme rowers 2500 years ago (10 February, p 46). Only 150 years ago a trained railway “navvy” in the UK was expected to dig out 1 ton of material a day, as I read in a biography of the Victorian civil engineer Robert Stephenson. The steel plates for the box girder sections of his 1850 Britannia Bridge across the Menai Strait were forged by men wielding 40-pound (18-kilogram) sledgehammers. The standard heavy sledge in use today is 14-pound (6.3 kilograms). I have used a 28-pound (13-kilogram) hammer, but it is not something I would recommend, even if you can still get them.
A 19th-century potter throwing flowerpots would use half a tonne of clay in a day. In 1972 in Uttar Pradesh, India, I witnessed 1.5-metre-tall labourers, who could not have weighed more than about 45 kilograms, lifting bags of rice probably weighing 70 kilograms, by rolling the hessian at the top to obtain a grip and hoisting them up and onto their backs with ease.
I suspect working toughness is what is missing now 鈥� something not possible to acquire in a gym.
Teens' substance abuse
In describing “Robo-tripping” you say the abuse of cough medicines such as DXM is “driven largely by the internet” (3 February, p 48). Many websites offer information, but I cannot believe this has led many more kids to abuse DXM.
Listening to peers and following fads is the number one factor. There are songs and cartoons that glorify tripping on the magic syrup, such as MC Chris’s The Tussin. If anything, the internet is educating teens how to “safely” trip, by suggesting products with only DXM as an active ingredient.
Cool running
Jean-Jacques Juillet, who is helping to build the Planck probe to get better measurements of the cosmic microwave background, claims that parts of the electronics “will be the coldest objects in the universe during their lifetime”, at 0.1 kelvin (10 February, p 5).
But then you describe an experiment that will cool several million rubidium atoms to “a few millionths of a degree above absolute zero” (p 26). In which case, won’t they be the coldest objects in the universe?
Dichloroacetate and cancer
It is fascinating to see that Evangelos Michelakis has revived the theory that glycolysis and lactic acid metabolism are involved in cancer (20 January, p 13). This was first proposed by the Nobel-prizewinning biochemist Otto Warburg in The Metabolism of Tumours (1930).
The idea was mentioned by Rachel Carson in Silent Spring (1962) and pursued over some years by Joseph Gold of the Syracuse Cancer Research Institute, New York. He has described it in a series of publications: for example, “Proposed Treatment of Cancer by Inhibition of Gluconeogenesis” in Oncology, vol 22, p 185, in 1968 and “Cancer Cachexia and Gluconeogenesis”, Annals of the New York Academy of Sciences, vol 230, p 103, in 1974.
In 1975 Gold proposed the use of hydrazine sulphate, better known as a rocket fuel, as an inhibitor of gluconeogenesis and to strengthen the effects of various anti-tumour agents (Oncology, vol 31, p 44), and this experimental treatment was also tried in the Soviet Union by V. A. Filov at the Petrov Research Institute of Oncology in what was then Leningrad (Cancer Treatment Reports, vol 60, p 933, and in publications by the Petrov Research Institute and the Tomsk Institute of Medicine, 1977).
Hydrazine sulphate has more recently been reported as an internet quack cure, and newspaper warnings have appeared about liver and kidney failure. The new research by Michelakis using the drug dichloroacetate seems a more promising treatment and one that will perhaps encourage people to revisit the original ideas of Warburg and his followers.
Fires, forests and climate
The effect of forest and bush fires on the amount of carbon dioxide in the atmosphere is a “hot” topic of research around the world (27 January, p 20). Whether it increases the CO2 burden or not seems to depend on geography and on the timescale over which estimates are made as well as other factors.
The Australian Greenhouse Office, within the government’s Department of the Environment and Water Resources, says: “The amount of carbon emitted to the atmosphere during bush fires is, when averaged over time, balanced by the amount taken up in subsequent forest regrowth. This relationship holds so long as the fire regime remains unchanged. However, if there is a shift to more frequent and/or more intense fire regimes due to climate change, there could be a discernable decline in forest carbon stocks” ().
For fires in forests near the Arctic, there appears to be an initial warming effect, but averaged over the longer fire cycle of 80 years a cooling effect occurs (Science, vol 314, p 1130).
This all goes to show that we need to understand these and all of the other complex effects involved in climate change better before offering carbon credits willy-nilly to all and sundry.
No time riots
Your interesting article on the origin of the Gregorian calendar (23 December 2006, p 40) and the follow-up letter pointing out that due to the calendar change people had paid rent for non-existent days (20 January, p 19) may leave the impression that the English population did indeed riot against the government’s removal of 11 days from the calendar in 1752. In fact, these supposed riots are a myth 鈥� albeit an appealing one.
Careful research by the historian Robert Poole has shown that there were no riots, only some discontent at the upset to the rhythm of familiar festivals, notably Christmas. The only explicit contemporary reference to the notorious “lost” 11 days appears to be William Hogarth’s satirical painting of 1755, An Election Entertainment, which shows a placard on the floor with the words “Give us our eleven days”. It refers to a rowdy election in Oxfordshire in 1754, two years after the calendar change. Poole’s research appears in History Today, vol 49, p 40.
Repair liability
Richard Holroyd suggests that the lifetime of products such as microwaves would be extended if users learned to replace internal fuses (10 February, p 18). This hints at a dilemma for product designers.
Fuses used to be unreliable and their current ratings were often chosen by informed guesswork. Now they are reliable, and safety testing has made the accurate selection of fuse rating a necessity.
A fuse blowing in a modern piece of equipment is (generally) caused by an internal fault. Replacing it with one of the correct rating results in the new fuse blowing, though perhaps not immediately. This, of course, can be “cured” by replacing the fuse by one of higher current rating; a piece of kitchen foil or a nail are even less likely to fail [do not try this at home 鈥� Ed.].
If the user does this, the manufacturer is in serious danger of an accusation that the product caused a fire, perhaps even loss of life. It may be quite difficult to prove otherwise, especially if kitchen foil was used, because it would have disappeared in the fire.
This serious legal problem can be solved by making the fuses inaccessible without the use of a tool. If the owner uses a tool, that shows an intention to do something he or she is not trained to know how to do.