Organic means safe
Anthony Trewavas suggests that because organic farmers do not use fungicides and most other pesticides, their products must have higher levels of potentially toxic fungal diseases (6 April, p 50). This is an old story and the evidence does not support him.
Many studies have found no significant difference in mycotoxin levels between organic and non-organic food. It is easy to assume that fungal attacks will be higher when no fungicides are used, but farmers often find that fungal attacks fall when they adopt organic methods. This is because there is a link between the use of fertilisers and plants’ susceptibility to fungal and insect attacks. Fertilisers force plants to grow at an unnatural rate, making their cell walls thinner and more prone to external attacks.
Trewavas should really not be encouraging people to consume food containing pesticide residues. The long-term and “cocktail” effect of mixtures of pesticides have not been tested for. In Britain, multiple residues occur in about 12 per cent of our food. The available evidence indicates that the toxicity levels of such mixtures can be very much higher than the “safe” levels for individual pesticides. The Food Standards Agency is now looking into this subject.
Interestingly, organic production also results in food with higher nutrient levels. While government data suggests that nutrient levels in food have fallen substantially since the introduction of agrochemicals, recent reviews of studies of organic food have found higher levels of all the nutritional minerals studied, including significantly higher levels of iron, magnesium, phosphorus and vitamin C, than in non-organic food.
Viewing isn't doing
To say that it is accepted that viewing violence makes children more likely to behave that way, as Alison Motluk does (6 April, p 16), is like saying Ptolemy’s version of the Solar System is accepted. Only highly partial researchers in the US “accept” this view. Those of us who study the media for a living largely refute such claims.
As far back as the 1940s, empirical studies have refuted the suggested effects of mass media on behaviour, yet researchers persist with their claims. Then you have sampling issues, particularly in the context of New York City, which in the period covered has seen a remarkable transformation of its crime rates, peaking in the 1980s, and declining in the later 1990s. Does the study even mention this? How does it relate to violence on TV?
Watching about 3 hours of TV is about the average for viewers in the US, so how come the majority of people aren’t out committing violent acts if TV is to blame? How come that in countries like Britain, and especially Japan, where both average TV viewing rates and levels of violence on TV are comparable to the US, crime rates鈥攑articularly violent crimes such as murder鈥攁re far less common than in the US?
Government and corporate funding for research in the US tends to go to studies that blame TV for crime, rather than, for example, gun laws. In fact, TV is a red herring, and I would have expected your normally astute reporters to know this.
Judge for yourself
Your editorial included false speculation alongside your fair reporting of our statement from Nature that our previous publication of a report of artificial genetic modification in Mexican maize was not after all justified by the available evidence (13 April, p 3).
You speculate that Nature is pressured to find a reason to publish papers, and inadequate ones at that, because of competition. This is simply not the case. There are quite enough first-rate scientific papers for “high-status journals” to publish. We publish fewer than 10 per cent of the papers we receive. Because scientists value quality, competition drives standards up, not down.
You also suggest that we “seem to be failing” in our duty by leaving readers to judge for themselves in this particular case. This transparency related to the supplementary data provided by the authors of the original paper. These data were relevant to the readership in the light of claims being made.
Our primary duty was to publish the criticisms, and to communicate our revised and negative view of the original paper. This we did.
Hubs of disease
Contrary to the assertions made in David Cohen’s report on scale-free networks, concentrating attention on hubs of infection is standard practice in many areas of infectious disease epidemiology (13 April, p 24). Contact tracing and the identification and treatment of hub individuals has been a key component of sexually transmitted disease control in Britain for many years.
This approach was used to develop the sexually transmitted disease hypothesis for HIV infection in the early 1980s. Control of hub individuals is also a central component in the control of food-borne infection鈥攂y putting restrictions of carriers working as food handlers, for example.
Many public health interventions also focus on hub locations. An example is activities for HIV control in clubs, pubs, saunas and cruising spots likely to be used by gay and bisexual people.
It is good news, however, that we now have a more formal description of networks of infection available to us.
What women want
Any male chauvinists who feared that their views were no longer represented in the medical profession must have been reassured by the letter from Mark Donohoe about periods (6 April, p 50.)
Donohoe expresses his “dismay” that the medical profession continues to “interfere with the normal function and physiology of women, most obviously in fertility control, through HRT and during childbirth”. Conveniently for his case, he ignores the statement in the original article (16 March, p 38) that “some of the best evidence that incessant menstruation is not what nature intended comes from our ancestors”.
In support of his case, Donohoe quotes, at length, his experience of his patient with haemochromatosis. This is a rare metabolic condition in which the body is unable to deal with iron, resulting in toxic overload. The traditional treatment for this was regular bloodletting. To argue that all women should have regular periods because this one patient benefited from regular blood loss seems to me to be less than persuasive.
Two of my great-grandmothers had 14 children each. This is the direction in which Donohoe’s “non-interference” would lead us.
Say that again?
There must be something about politicians (13 April, p 53). When I was a reporter at the Saskatoon Star Phoenix responsible for a small item called “Quote of the Day”, my favourite was a quote on a government initiative from a member of the Saskatchewan legislature. It was: “We are halfway down the road but we don’t know how long the road is.”
Correction
In our article on the moves to change the head of the Intergovernmental Panel on Climate Change (20 April, p 16), we said Steve Schneider is at Princeton University, New Jersey. He is actually based at Stanford University, California.
Asian Eden
If botanist Barrie Juniper is correct and the apple did originate in the Tien Shan mountains (13 April, p 46), then the Soviets were right in 1921 to rename the old Tsarist outpost of Verny at the foot of the range “Almaty”. In Kazakh, the name means “Grandfather of the Apples”, appropriate for the original apple breeder, Juniper’s ancient bear.
Leaving your body
Feedback considers that Betty Shine’s suggestion to people meditating鈥攖hat they should pretend they are a tree to “ground” themselves and so avoid the risks of leaving their body and not being able to return鈥攊s inadequate (13 April).
Does Feedback have evidence (even anecdotal will do) that any practitioners using this safety net anywhere in the Universe have been unable to return to their bodies? If not, then I suggest that Shine’s answer is perfectly adequate鈥攁s effective, in fact, as the device I employ in the back garden of my Northamptonshire townhouse to keep elephants away.
Nuclear liability
There has been concern because a reference to liability insurance as part of the external costs of nuclear power appears to have been removed from the final version of the British government’s draft energy review, apparently because of “the difficulty of quantifying the possible costs of accidents” (16 March, p 57, and 6 April, p 50). But if British Nuclear Insurers is prepared to use its unique experience for the public interest by estimating monetary values for environmental risks for new nuclear plants, then there is a good chance of overcoming these difficulties.
I suggest a challenge for BNI. Estimate the possible range of premiums required to provide a selection of realistic limits for nuclear liability insurance for new plants: say 拢5 billion, 拢10 billion, 拢20 billion, 拢50 billion and 拢100 billion. State the difficulties involved in making the estimates. Then collaborate with manufacturers in assessing how insurance costs could be reduced by better plant design.
Nuclear power, like all other existing generation technologies, only has a sustainable future if it can face up to its true external costs and then adapt to reduce them to levels which reflect the value of the power it generates.