Sustainable economics
In his critique of sustainable economics, Thomas Hogg ignores the fundamental argument in its favour: that unrestrained growth will eventually bankrupt the planet (8 November, p 20). Instead, he claims that scientists do not realise that zero growth is a feature of recession and therefore, he assumes, inherently bad.
He completely misses the point that a truly sustainable economy would not be remotely similar to a dysfunctional greed-economy during a downswing. Hogg accuses you of proposing a system of “authoritarian control” by an “all-knowing central agency”. Yet no contributor to your special report on economic growth (18 October, p 40) advocated anything of the sort. Instead, all the suggestions were precisely of the kind that Hogg claims were lacking: sound economic incentives to encourage more sustainable behaviour.
Tim Jackson suggests that our model of economic growth is doomed (18 October, p 42). This need not be so. Thanks to digital technology, while I cannot grow my CD collection forever, I can grow my MP3 collection. I can also expect better-quality movies, computer games and software almost indefinitely. We can rearrange the molecules that we have into more valuable possessions 鈥� recycling our shoulder-padded jackets and tape recorders into fashionable clothing and iPods. As long as we have energy 鈥� the sun is good for a while yet 鈥� we can reverse entropy locally using techniques such as robotic sorting, biorefining and plasma extraction to recycle forever.
On the intellectual side, there is no reason we cannot continue to grow in our understanding and in our artistic accomplishments through continued research and programming. The one thing we cannot grow safely is our population. Fortunately, our biology lets one child embody the hopes and dreams of two parents, so a non-traumatic solution to the problem may be possible.
Richmond, British Columbia, Canada
鈥� Our contributors are agreed that we have to replace growth in quantity with qualitative growth 鈥� development in other words. We also have to deal with the “rebound effect”, exemplified by someone earning money with minimal environmental impact by developing computer games but then spending it to fly off to go snowboarding.
Testosterone screening
Contrary to what your report says, I am satisfied with the latest guidelines on who to screen for testosterone deficiency and how to treat it (1 November, p 8). I do not think they should go further, especially not until there is more evidence in relation to diabetes.
The European Association of Urology guidelines do state that doctors should check testosterone levels in all men with erectile dysfunction. If further trials give evidence of improvements in metabolic and cardiovascular function when diabetic men receive testosterone replacement therapy, then men with diabetes should be screened for low levels of the hormone. However, hypogonadism 鈥� poor functioning of the testes 鈥� has non-specific symptoms that are present in many men and may be due to other conditions. Up to 70 per cent of men with type 2 diabetes have erectile dysfunction and our study published in Diabetes Care in 2007 () showed that a high proportion of men with diabetes have tiredness and fatigue, reduced muscle strength and mood changes. This does not mean that they are all testosterone deficient.
We did find testosterone replacement had beneficial effects on insulin sensitivity and cardiovascular disease, and there appear to be no adverse effects using it in men with diabetes. We now need larger and longer-term studies 鈥� which will be expensive.
From Andre Araujo,
I was disappointed to see that you missed one critical point: the updated guidelines are at odds with current drug labelling that warns against giving testosterone to men with a history of prostate cancer. Clinical guidelines should be conservative, not ahead of the evidence, which these appear to be.
Watertown, Massachusetts, US
Unreliable ritual
Mark Buchanan’s discussion of spurious causality (1 November, p 15) reminds me of an observation I repeatedly make when advising on risk analysis: that the attention given to a countermeasure or procedure is often inversely related to its effectiveness, especially when no clear measure of its effectiveness is available.
Fairly effective are: orbit predictions, vaccination, insurance cover, short-term weather forecasts and good policing. Pretty ineffective are: tarot cards, lucky charms, petition to a deity, long-term stock-market or political forecasts, faith healing and increasing the penalties for crime.
So an effective measure 鈥� such as polio vaccination 鈥� is routinely carried out with no fuss. An ineffective one 鈥� like a human sacrifice to boost the harvest 鈥� is accompanied by much incantation and knife-blessing. Any success is then put down to the sacrifice, whereas failure is laid at the door of incorrect ritual.
Where something absolutely must be done, but no really effective measure exists, ritual 鈥� including oratory 鈥� is all we have.
Renewable energy
Your discussion of renewable energy was heavily focused on its large-scale applications (11 October, p 30). These are an option, but we can think far more progressively and make the change to renewables concurrent with a change towards a decentralised power supply.
What happened to the idea of moderately self-sustaining solar-powered homes that receive back-up help from the grid? Have power companies successfully shifted the focus on renewables toward a market based on the same ideology and supply chain as our current system?
Solar is the only real solution without massive problems of infrastructure and environmental disturbance. Even here in Philadelphia, hardly part of the “sun belt”, current technology is more than capable of sustaining most of a home’s energy supply at a cost that is only slightly out of reach for most consumers. We need to get away from the idea of corporate control over energy, because individual energy production gives far more empowerment, control and monetary incentive to those using the energy.
From Colin Gray,
Helen Knight gives a somewhat alarming projection of the variability of electricity supply if it were to be generated from 100 per cent renewable sources. What about the contribution of biomass burners and anaerobic digestion to energy supply?
Like well-understood hydro schemes, such systems can produce a steady, or on-demand, source of energy. Many of their renewable feedstocks 鈥� wood, refuse-derived fuel, animal slurry, food wastes and straw 鈥� are already providing electricity to grids through co-firing with coal. Then we have dedicated biomass burners and gas turbines running off the methane generated from anaerobic digesters, many in turn providing heat to local houses, schools, industry and so forth.
Gateshead, Tyne and Wear, UK
Battery bonus
Owen Clarke expressed concern about “peak lithium” and the limits it might place on the production of electric-car batteries (11 October, p 20). A lithium-ion battery with a capacity of 60 kilowatt-hours would contain about 5 kilograms of lithium, according to .
The US Bureau of Mines reported in 1990 that the available world resources of lithium are about 13 million tonnes, although geologist R. Keith Evans . Either figure allows for the production of several billion batteries for several billion cars. And the lithium is recyclable, so batteries can be renewed without requiring new lithium. “Peak lithium” is not a concern in the same sense as is “peak oil”.
Computer says go
I appreciate your concern that the use of brain scans in evidence could result in wrongful convictions (4 October, p 5). But a more useful question is: might fMRI scans prevent or overturn some wrongful convictions?
In 1998, criminologist cautiously estimated that 2 per cent of prisoners had been wrongly convicted. Extrapolating to today’s prison population implies that 1600 people in the UK could now be suffering undeserved imprisonment. I understand that the and the law lord Harry Woolf have suggested even higher figures.
The question that should be researched with all deliberate speed is this: could fMRI identify these wrongly convicted prisoners? There are interest groups that could identify cohorts of people who have completed their sentences while protesting their innocence. We could compare their scans with innocent volunteer controls, and with volunteer serving prisoners who have admitted their crimes.
A dog in time
I am struck once again that scientists researching animal cognition 鈥� in this case, thinking backwards and forwards in time 鈥� assume that other animals are fundamentally different from us unless proved otherwise (1 November, p 32). Why is this? We are, after all, part of the same evolutionary continuum. Charles Darwin believed that differences between human and non-human animals were quantitative rather than qualitative.
In the specific case of memory and planning, I find it hard to believe that real learning (excluding conditioned reflex) can occur without memory. You have previously reported that in humans the same brain pathways are used when remembering real events and when imagining possible events 鈥� the basis of planning (24 March 2007, p 36). Is there any reason to assume that this is not true of other animals?
Being able to learn from experience, and adjust future behaviour accordingly, must have such an impact on survival and success that it is surely selected for. It seems to me more likely that a wide range of animals can do this, with varying degrees of competence, than that there is a fundamental difference in the way in which humans think.
I was dumbfounded at your article on episodic memory and foresight in animals, and so was my dog. Any human who has watched a greedy Labrador discover an unexpected pile of edible material abandoned in the woods and then been forcibly dragged back by the dog on the next and following days will recognise that the dog has recorded a unique experience; can locate the place in which it happened; find a route to it; and has hopeful expectancy of a repeat experience.
I have no doubt that the dog’s dreams are full of the experience. Can it dream and hope without being aware? Nonsense! And that is fairly simple dog behaviour.
Comparative psychologists should get out more, and keep their eyes and minds open when they do so. Or are they frightened of the implications of being surrounded by aware creatures?
Sutton Coldfield, West Midlands, UK
Marvel at mind mystery
A. C. Grayling muses on why it is so difficult for the brain to understand itself (4 October, p 50). Is this because it’s too marvellous, or because it is not marvellous enough?
For the record
鈥� We reported questions over the stability of NASA’s Ares I rocket design in winds of 20 kilometres per hour, based on a (1 November, p 6). At a NASA press briefing on 29 October, the agency said that the true figure is 63 kilometres per hour, and that this is only reached about 0.3 per cent of the time.
鈥� The figures in our table on travel risk were for transport accidents (not including sporting “travel”) and were from the UK’s Department for Transport, not the UN as stated in a caption (30 August, p 34).
鈥� We misattributed a study of the language-trained chimpanzee Panzee pointing to previously hidden objects to Emil Menzel (1 November, p 32). It was conducted by Emil’s son, Charles R. Menzel.
鈥� We referred to an Eileen Todd at the California Environmental Protection Agency (11 October, p 12). That should have been Eileen Tutt. Sorry.
Long and windy path for turbines
Practical considerations will limit most wind turbine projects and installations to the 2.5 to 3-megawatt size range (11 October, p 33). Component size, fabrication, transportability and erection become increasingly overwhelming and costly as the desired power output rises. The blades of a 5-megawatt turbine will be 90 metres long, and those for a 10-megawatt turbine 115 metres. How do you transport such blades thousands of kilometres to the erection site in one piece?
Cash for questions, automated
I was excited to read that a computer program had fooled a quarter of the judges into thinking it was human in a 5-minute text-based conversation, thereby winning this year’s Loebner prize (online news, 13 October). This is just under the 30 per cent required to pass their version of the Turing test, which has stood for 50 years as the benchmark to test whether software can think for itself. From the press coverage you might be forgiven for fearing scientient computers were about to march out over the world in a Schwarzenegger-inspired apocalypse.
But, unbeknownst to many, man-made intelligence lives among us and already passes the Turing test. Examples include customer email auto-responders; SMS information services; online interactive assistants; celebrity text lines which respond to users in the signature style of the celebrity; automated flirting software and malicious online robots that stalk gambling sites, preying on unsuspecting humans for real money.
In the real world, a well-designed interface can overcome the problems that brute-force computing cannot. A limited context helps: you would hope a double glazing firm would only get questions about windows. Keep a database of successfully answered questions, back it up with a human operator to handle difficult queries, and if all else fails, pretend to be young, foreign, funny or Ozzy Osbourne.
Most of the time, the user won’t know or won’t care about the origin of the message as long as they get good service. The real test is getting people to pay for meaningful automated interaction and it has already been passed.
鈥� While David Bateman was writing this, Nic Fleming was writing an article on poker-playing robots (15 November, p 28).
Waste not, want not
You report the high environmental cost of meat (13 September, p 28). Vast numbers of animals are killed worldwide as pests, or culled on environmental grounds. I admit that the “Multiple McLocust” may not be a marketing dream, and Australia’s cane toads are unfortunately toxic, but rabbits are an under-used resource. Before anyone complains too much, they should review other attempts at control. Introduced predators (foxes and cats) found local marsupials easier prey, while myxomatosis and calcivirus hardly represent a morally superior solution.
Into the unknown at CERN
Valerie Jamieson ignored one significant source of concern about the experiments to be conducted at the (27 September, p 18), though she did allude to it when referring to “the cultural illiteracy of scientists”.
I suspect the concern arose not from a public ignorance of physics, but from statements made by several of the scientists involved. Intending to ramp up the excitement, they emphasised that they were entering unknown territory.
Well obviously, that is why you do experiments, but it came across as “We don’t know what we are doing”. So people were getting mixed messages: “It’s perfectly safe” and “We haven’t a clue”. Opposition then arose from a concern about due diligence.
Cancer screening
I am concerned that the prostate-specific antigen (PSA) test is often written off as having little if any value, as you do (25 October, p 31). Since I owe my life to the test, I believe it does have real value. With both my father and uncle suffering from prostate cancer, we, the next generation, were clearly at risk and undertook regular tests.
A very slow change over two-and-a-half years, starting at a PSA score of 4.2, might well have meant mild enlargement of the prostate gland. In May 2003, with the figure reaching 6.2, I decided to have a biopsy to confirm the situation. Two out of eight samples showed very minor changes, and four surgeons all said that I had no need to worry unless the figure reached 10.
I decided to take action at a value of 8: in January 2004 it reached 9.5. Radical surgery showed that the cancer was very aggressive, was still contained but was now 50 per cent of the gland. The treatment appears to have been totally successful.
Someone I know has a PSA figure of 70 but it is non-malignant. I suggest that the message needs to be communicated that the test can be of great value. Regular tests are needed: the absolute figure is not as important as spotting sudden changes in the rate of increase.
鈥� For these relatively rare aggressive tumours, PSA may be a lifesaver. The trouble is, for most men with prostate cancer, it is not. All would be better served by tests that specifically recognise aggressive tumours, as the article pointed out.
I was disappointed to find not one mention of breastfeeding as a form of breast cancer prevention even though you wrote at length about treatment of cancer, with numerous references to breast cancer.
The beauty of breastfeeding is that 99 per cent of mothers are capable of it, it’s free, and has many other benefits besides breast cancer prevention. A high-profile, nationwide campaign to promote breastfeeding (with the necessary support provided as standard) would, I dare say, save the NHS a lot more money over the years than screening programmes and the use of modern drugs and/or procedures.
You discuss personalising cancer therapies to specific diseases, and the costs this may engender (25 October, p 5), highlighting the issue of Herceptin being inappropriately prescribed in the US.
This issue is perhaps best highlighted by the drug Vectibix (panitumumab) made by Amgen for use in metastatic colorectal cancer. It is a monoclonal antibody that targets epidermal growth factor receptors. It can work only if the patient has the “wild-type” of a protein called K-ras. However, 36 per cent of patients with advanced colorectal cancer carry a K-ras mutation that means the protein is always “switched on” in the signalling pathway, rendering Vectibix ineffective.
Vectibix is approved in the US and Europe 鈥� but only in Europe is it a condition of prescription that the patient must test negative for the K-ras mutation.
It is worth noting that the US Food and Drug Administration already has biomarker testing requirements for a number of drugs (see ). I hope this practice will be extended as the paradigm shift toward biomarker-directed medicine continues.
Drug companies and governments need to work together to bring about this biotechnology revolution in the way that is most beneficial to society. We must be careful to avoid either pushing or allowing drug companies effectively to use genetic profiling to drive their business model.