Degraded land
There is little doubt that transgenic technology and other forms of plant breeding will produce plenty of crops like trehalose-rich rice that can grow better on salty, drought-prone soils in cold and arid conditions (30 November, p 10).
But has anyone questioned the wisdom of continuing to grow crops in regions where soils have been ruined by centuries of overgrazing and inappropriate irrigation?
There is also the issue of introducing arable farming into desert regions that harbour fragile and valuable ecosystems. People in these areas desperately need to produce food for themselves, but more than this they need access to agricultural methods that ensure that this can be sustained 鈥� if such methods exist.
By developing plant varieties that allow damaging agricultural practices to persist we run the risk of exacerbating existing soil salination problems, and may increase the demand for irrigation in areas where water resources are growing scarce.
The search for sustainable food supplies in arid saline areas is primarily about finding sustainable agricultural strategies, and should not be sidetracked by debates about plant-breeding methods. I hope that the Rockefeller Institute, which backed the rice project, is also considering what effects these new cereal varieties might have on environments that are already seriously degraded.
Is wholemeal refined?
I was interested in Douglas Fox’s article suggesting that the rush of insulin after eating refined flours was to blame for acne (7 December, p 23). Does the concept of refined flours include modern wholemeal flour?
Letter
鈥� Wholemeal products could also produce a significant glucose spike, and therefore contribute to the problem. This is because wholemeal products are milled and ground into very small particles just like white flour is. As a result, the starches are broken down by enzymes just as rapidly. There is, however, a bread that does not produce such a significant glucose (and insulin) spike: this bread. In wholegrain bread, grains are left more or less intact rather than being ground into fine particles, and so are digested much more slowly.
Cleaning diesel
The fact that some diesel engines are still being built without effective soot filters is not due to a lack of adequate technical solutions (30 November, p 53).
Peugeot and Citro毛n have been selling cars equipped with these exhaust filters, such as the Peugeot 607, since 1999. The filters have been proved effective by independent bodies such as the ADAC (the German equivalent of the British Automobile Association), and found to remain 99.9 per cent effective after 80,000 kilometres.
The only obstacles to our enjoying the full environmental benefits that diesel engines can offer are political, and to a lesser extent commercial.
Dishwashers and sinks
Your article on dishwashers is a little misleading (7 December, p 27). If you want to compare the water consumption of a dishwasher with the amount used when washing dishes by hand, you must include the water involved in the construction of the dishwasher. While I agree that certain manual dishwashing methods will use more water than a dishwasher, there are a number of other issues which need to be included in the final equation.
This may seem pedantic, but the “cradle-to-grave” approach to environmental impact assessment is crucial in allowing people to make a fully informed decision.
Forecast forecasts
Feedback makes fun of the idea of trying to forecast the weather forecast (7 December). But predicting forecasts may be a very sensible thing to do, at least in the world of finance.
Stock market traders use weather forecasts in well determined ways to set the price of, say, oil and cocoa futures. So the way to make money is not to waste time on predicting the weather, which is horribly complicated, but instead predict the forecasts, which is much simpler. If you know what tomorrow’s forecast will be, you can predict which the way the futures will move and cash in on the difference.
Or so I have been told.
True prophesies
Sherwood Idso describes Irakli Loladze and, by implication, anyone else who does not believe that vastly elevated carbon dioxide levels are an unalloyed benefit to humanity, as “Cassandras” (30 November, p 26). He needs to reread his classics.
Cassandra was cursed by Apollo so that her prophecies would always be true and never be heeded. The Trojans ignored her warnings about the war with the Greeks and as a result their entire culture was destroyed. While I fear that this analogy may prove to be all too accurate, I suspect it is not the impression Idso intended to convey.
Printing for history
Martin Rees expresses a reluctance to “go to the wall to defend print journals” (23 November, p 27). For him, the electronic preprint archives, among other things, render science more “democratic”, since new ideas aren’t quickly squelched by all those tired old editors of the mainstream print journals.
But what would be lost if print journals disappeared is any sense of historical progression in science. E-prints might capture an audience for a time, but without a presence in the real archive 鈥� print journals 鈥� theirs would be but a fleeting popularity, always vulnerable to the next scientific fad to come along. To make matters worse, e-print archives may not be secure. When stored on hard drives they are prone to physical decay, and guidelines for their ownership and maintenance are unclear.
By contrast, print journals archives have stood the test of time in academic libraries the world over. There one can find, for example, that Isaac Newton proposed one of the first “pushing gravity” models; that Fritz Zwicky proposed a “tired light” model for galactic red shifts shortly after their discovery by Edwin Hubble; and that J. T. Wilson, one of the founders of plate tectonics, also flirted with an expanding Earth.
That such ideas are with us at all today is in large part because they were once published in print journals. A sure-fire way to marginalise alternative ideas would be to package them solely in e-prints.
Starving plants
Your article on rising carbon dioxide levels and potential nutrient problems with plants was very interesting and raised a vital issue (30 November, p 26). However, the article focused solely on humans and their crops, which I think is only a small part of the overall picture.
The prospect of malnourishment for countless herbivore species, from soil fauna to antelope, is very frightening and would be an unprecedented calamity for all life on the planet. And it’s obviously not possible to provide vitamin supplements for all these organisms.
On the other hand, some plants outperform others with regard to mineral nutrient uptake. In numerous studies of weed competition in crops, many weed species have been shown to draw mineral nutrients from the soil two to three times as fast as crops. In other words, they contain genes that could be incorporated into crops to improve their nutrient uptake. Which would help people (and crop pests) but might not do so much for the rest of Earth’s creatures.
Goose and gander
Menachem Magidor, in his interview with Michael Bond, remains unscientifically evasive about his readiness to accept “heretical” views (30 November, p 44).
He insists on his university’s ideological commitment, while suggesting that his equivalent at Birzeit, the Palestinian university outside Ramallah, should not “be part of any kind of ideological or political agenda”. Not logically coherent 鈥� especially from a mathematician. Be fair!
Letter
鈥� As Matthew Barrett and Martin Bland point out, the Horizon experiment was as powerful statistically as the earlier study by Madeleine Ennis. What concerned critics of the programme was that her study was itself based on a relatively small sample size. As such, neither Ennis’s study nor any replication of it could justify the programme’s title of “Homeopathy 鈥� the Test”.
After discussing the statistical issues behind the experiment, Bland told me: “I am not going to reveal anything which was not in the Horizon programme, as this would certainly prejudice our chances of publication”. I therefore respected his wishes, and quoted him solely on what he was happy to state publicly.
Letter
Robert Matthews accuses the Horizon homeopathy experiment of being flawed because the sample size was too small. It is impossible in a popular television programme to give a full scientific account of a piece of research, and we were unable to discuss this issue on air. I was asked to review the Horizon protocol and concluded that the study had high statistical power to detect a difference of one standard deviation. In my opinion this was adequate. I did not decline to comment on the issue of sample size, as Matthews says, but sent him exactly what I had written for Horizon.
I had not at that time seen the paper by Ennis on which the Horizon protocol was based. But it suggests that the average inhibition of action reported for her histamine dilutions was about 15 per cent. In the Horizon data, the standard deviation of percentage activity in the control tubes was 1.5 and the mean was 10.5, hence one standard deviation was just under 15 per cent. If the difference in the population were similar to that found by Ennis, the probability that our study would detect a difference in the sample would be 90 per cent. I think that this confirms that the sample size was adequate as a replication of Ennis’s study.
To show that water does have a memory, we must have an experimental system which is repeatable in any competent hands and under the most stringent conditions of blinding and randomisation. So far as I know, we do not have this. The Horizon experiment suggests that the system used by Ennis does not match these criteria.
We stick by our trial
We could not help feeling that Robert Matthews’s article claiming that our homeopathy trial was “flawed” was rather mischievous (7 December, p 10). He made no mention of the fact that the experiment was performed to the satisfaction of two of Britain’s top laboratories and under the guidance of John Enderby. All agreed that it was a valid test of the “memory of water” hypothesis.
The sole criticism voiced by Madeleine Ennis 鈥� that the sample size was too small 鈥� was particularly strange since our sample size was, we believe, at least as large as the one she used. Likewise we used the counting method that she recommended to us.
The article went on to state that the Horizon experiment was “incapable of making a definitive conclusion”. This is, of course, a truism: no single experiment is ever definitive.
Lastly, if the unnamed critics believe that our experiment should have been performed differently then they are welcome to perform the experiment themselves, taking rigorous precautions to make it double blind. If James Randi’s million dollar prize doesn’t interest them, then there’s probably also a Nobel prize for whoever can confirm the existence of the memory of water.