Tainted aid
It is untrue to say that Zimbabwe, or any other country in Southern Africa, has refused food aid that contains genetically modified maize, as you state in your Editorial (3 August, p 3). What they have turned away, as your report on page 4 says, is unmilled GM maize that could be planted. I understand that requests to the donor to mill it have so far been rejected. Zimbabwe is not the only country to have made this request.
The unfortunate implication that this is due to a lack of understanding in the region about the implications of GM technology is very far from the truth. Indeed, the GM debate here seems to be conducted at a far higher and less hysterical level than I see it is in Britain.
This is not just a Zimbabwean issue, but one that affects the whole of southern Africa. All the countries in the region are being forced to consider their response to the importing of GM food products. All are currently working on issues concerned with biosafety and local biodiversity, having endorsed the Cartagena Protocol on Biosafety, and the nub of the problem is a simple one. This part of the world exports food mainly to Europe for the high-quality end of the market. Its beef, in particular, is renowned not only for its excellent taste, but also for the fact that it can all be guaranteed wholly organic. The concern amongst agronomists here is that this market strength will vanish if there is even the slightest suspicion that products can no longer be guaranteed GM-free.
As the ActionAid statement pointed out, there is a widely expressed concern here that the refusal to mill GM maize before sending it as food aid may be an attempt to undermine the viability of the region’s agricultural sector by bringing its organic and GM-free status into question, thereby opening up the area to the high-tech seed multinationals. I have no means of judging the validity of this argument, but it would not be out of line with the general experience of the region. On the one hand, government subsidies on maize production have been discontinued under pressure from the World Trade Organization 鈥� precipitating, for example, a widespread switch from maize to cotton in Namibia. And on the other, Irish butter is dumped on the market and sells for 拢1 per kilogram, suppressing the local dairy industry.
It now seems that it’s OK for the starving here to eat subsidised maize, just as long as it is GM and grown in America.
People aren't bananas
Your report about genetic differences between people in different parts of the world was interesting (10 August, p 17). Apparently “modern inhabitants of Paris鈥� share an average of 50 per cent of their genes with people from Baghdad”.
Compare this with the frequently cited statistic: “Humans share 50 per cent of their genes with a banana.” Does this mean that the residents of Baghdad are bananas?
This is a common source of confusion, and no wonder. There are many different ways of comparing genetic similarity. The often quoted fact that people are genetically nearly identical to chimps, for example, comes from the analysis of amino acids coded for by just a couple of genes that we share with chimps. 98 per cent of those amino acids are the same.
The 50 per cent figure for people and bananas roughly means that half of our genes have counterparts in bananas. For example, both of us have some kind of gene that codes for cell growth, though these aren’t necessarily made up of the same DNA sequences.
The figures quoted for human populations are much more specific and are about gene variants. In this study, what is meant is that 50 per cent of the genes of all the people in Europe, on average, are specific types that have come directly from Middle Eastern populations. So no, the people of Baghdad are not bananas, and neither are we 鈥� Ed.
Weightless rocket
Your article claims that controlling gravity will not help launch spacecraft, because making them lighter will reduce the weight of the propellant (17 August, p 20). This, in turn, will reduce the rocket’s thrust.
However, the thrust of a rocket depends on the mass ejected in the exhaust, not its weight. Otherwise rockets would become less effective the further they were from a planet.
The thrust would only be decreased if the spaceship’s weight was lowered by reducing its mass. So perhaps research into antigravity is not so useless after all.
Richard Glover is correct. We failed to distinguish between a system that reduces gravity, and one that reduces mass 鈥� Ed.
Lives come first
The idea that avoiding radio interference is more important than saving lives is very offensive to me, as I’m sure it is to most people (3 August, p 8). Perhaps the management at the Radio Authority should adopt a more humane rather than bureaucratic approach.
Active ingredient
You report research that suggests semen may have antidepressant effects, and specifically that it contains hormones that reduce depression (29 June, p 5).
In 1985 I suggested that depression is due to reduced levels of dehydroepiandrosterone (DHEA), and research since then has supported this. In response to your article, here’s a quote from a 1976 paper: “In a group of men with established fertility, dehydroepiandrosterone sulphate had the highest concentration [in semen] and testosterone sulphate had the lowest” (Clinical Endocrinology, vol 5, p 253). I suggest that the antidepressant effects of semen are due to DHEA.
Wisdom in the stars
Brian Davies speculates on what science would be like if astronomy didn’t exist (10 August, p 22).
In the late 1980s Douglas Adams asked what a society would be like if no stars were visible from its planet. In Adams’s Life, The Universe and Everything, the people of Krikkit only discover that they are not alone when an alien spaceship crashes on their planet.
After rapidly developing of a space programme, they behold the Universe for the first time and decide that it has to be destroyed. Millennia of isolation have left them believing that they are the centre of the Universe. Finding that this is not the case destroys their sense of identity and prompts them to embark on a xenocidal war lasting 2000 years.
Letter
Your articles states: “Astrophysics and cosmology would have had to wait for 1950s technology 鈥� specifically planes such as the X-15 that could fly at high altitude, above the clouds.” I suggest that this more than a little unfair to pioneers of, say, cosmic ray studies. Victor Hess did experiments in a balloon in 1912, and Robert Millikan’s 1923 Nobel prizewinning work involved a Condor bomber. Not everything would have had to wait for the X-15.
Chemical sceptics
In your article on dopamine and belief in the paranormal (27 July, p 17) you say: “Whether or not you believe in the paranormal may depend entirely on your brain chemistry. People with high levels of dopamine are more likely to find significance in coincidences, and pick out meaning and patterns where there are none.”
But perhaps it is rather that insufficient levels of dopamine in the brains of sceptics prevent them from seeing what is actually there.
Go away, ET
You suggest making no reply if we detect an alien civilisation for fear of oppression (17 August, p 5). But surely this cuts both ways. If all ET civilisations have the same fear, none will be sending out signals, making the whole SETI project futile.
Letter
Perhaps the lack of detectable ET communications is because they have not been programmed in by the creators of our virtual world (27 July, p 48). Maybe this means that the simulation we live in isn’t designed to go much beyond the point were we have the technology to observe ET. Does this mean we have reached the end of our useful lives and are about to get switched off?
Letter
There is another reason why there have been very few SETI transmissions (17 August, p 27). Unlike passive SETI, you are 100 per cent certain not to receive a reply in your lifetime.
Silent teachers
Your article suggests that memorial services for medical school cadavers are uncommon (10 August, p 40). But there is also an annual event at Dundee University to give thanks to people who left their bodies to science. It is without doubt the busiest day of the year for the university’s chaplains.
One eulogy prepared by a student and read at the service described those who had chosen to donate their bodies as “silent teachers” who provide more than any book or computer-based simulation.
All shades of black
The comment that the black paint from Halfords is suitable “for all shades of black” is actually a useful piece of advice, and not worthy of Feedback’s scorn (10 August). There are over 2000 “shades” of black defined by the automotive coatings industry. Many of these are very similar but have different specifications from different companies, or the same company over a period of years.
Once you notice the number of black vintage cars on the road, you can understand that sometimes very old specifications are important. A difference of as little as 0.01 per cent in the amount of light absorbed would be easily discernable to the owner. And the tonal quality of the black, such as a blue or brown undertone, is also very important.
Pure dog dung
Brian Robinson states that “pure” was a term for the dog excrement used in infusions to treat skins and hides, but I am more familiar with the spelling “puer” (17 August, p 28). Dog dung contains pancreatic enzymes which were used in solution to attack the non-collagenous proteins in skins or hides. This was a purifying rather than a curing step, to clean the material prior to tanning. It also means that biotechnology has been used in the leather industry for at least 5000 years.
I have always been curious as to the origin of the term puer, although it is only one of many strange bits of jargon surrounding the art. I can only think that the job was so unpleasant that the “puermaster” left the handling of the materials to his lad, or puer in Latin.
Treating skins with dog dung was always called puering, and the use of infusions of bird guano was called “mastering”. Happily, the dung treatment is now obsolete, and nowadays the same general process is called “bating”, and typically involves manufactured bacterial or pancreatic enzymes. The process that it’s part of is one of humanity’s oldest technologies.
Weapons on planes
Further to Rachel Cave’s glass clubs (Feedback, 10 August), on a recent trip to Britain my partner and I were lolling about in the Qantas business lounge at Sydney airport. I decided to avail myself of the lavish fare spread out on a nearby sideboard, and noticed that alongside the handsome metal forks and spoons were plastic knives. Oh well, I thought, at least I’m safe from any evil-doers who want to run amok.
Some hours later, as I was being served the first meal of the flight, I was appalled to find that I was provided with a metal knife. I had half a mind to jump up brandishing the offending item, bellowing my indignation at whoever would listen, but you’ll be pleased to hear that I managed to sit quietly all the way to Singapore.
There, I boarded a KLM flight for Amsterdam, and again found myself given a vicious looking stainless-steel knife, while my nail clippers were stashed in the hold.
Humble words
Finding “The Who” on Google is fun, given the way the search engine ignores “humble” words (Feedback, 3 August). But how about this? I recently wanted to acquire some CDs by a band headed up by Matt Johnson. The band’s name? “The The”.