The sweet smell of dad
Reading Mairi Macleod’s article about the effect that the presence of a girl’s biological father has on the age she reaches puberty, I am surprised that more thought has not been given to the importance of chemical communications (10 February, p 38).
Something so fundamental to all life forms as pheromones should be expected to have a powerful influence on us too. Could it be that men’s pheromones have decreased because of the increase in bathing in the past 150 years or the more recent use of deodorants, which are known to be powerfully influential chemicals?
Our pheromones presumably evolved because they served a purpose. Have we disturbed a human communication medium that is critical to childhood development?
No quick carbon fix
While Richard Branson’s offer of $25 million for the first person to devise a way of scrubbing greenhouse gases out of the atmosphere is no doubt made with the best of intentions, it is misguided and more likely to be counterproductive to the cause (17 February, p 5).
First, it is exceedingly unlikely that there is any “magic bullet” solution to atmospheric scrubbing. We must bear in mind that several gases are involved, and the scale of the atmosphere.
Secondly, any research in this area will probably be specific to particular industrial processes. It will thus be conducted irrespective of whether or not there is a Branson prize.
Thirdly, and more seriously, the existence of this prize may well reinforce the inertial mindset within the broad population: “OK, we’ve got a problem, but science will come to the rescue, it usually does, so we don’t really need to change our behaviour, business as usual, while awaiting the scientific ‘fix’.”
From Charles Wartnaby
Ian Jones of the Ocean Technology Group at the University of Sydney, Australia, has suggested expending energy to synthesise fertiliser and using it to grow plankton in the ocean to capture carbon dioxide. Meanwhile, your article on urine recycling explained that CO2 would be saved by separating urine from sewage to avoid the cost of removing nitrogen and phosphorus (23/30 December 2006, p 45).
So why not combine these benefits and dump separated urine directly into sunny areas of open ocean? This notwithstanding the problem of hormones or their mimics in the urine, raised by Barbara Lai (27 January, p 21).
Meanwhile, ever-tighter vehicle emissions regulations, focused on air quality rather than climate change, are leading engine makers to fit new diesel exhaust systems with selective catalytic reduction units in which nitrogen oxides are removed by reacting them with urea. Urea is generally made energy-intensively from natural gas, through hydrogen and ammonia intermediates. As the new systems come on-stream, large quantities of urea will be required for the diesel vehicle fleet.
Recycling urine to yield urea solution could produce a useful energy saving, though some have joked that truck drivers could top up their tanks directly. I eagerly await my cheque for $25 million.
Cambridge, UK
The more the merrier
Paul Schaffner notes that Feedback is campaigning against reducible fractions, such as “twice every two hours” (10 February, p 19). Let me add that statistically, finding 3 in 300 is a more precise and probably more accurate result than 1 in 100. Even in a deterministic orbit of Mars, just as “1000 orbits in 1000 hours” conveys far more exact information than “once per hour”, “twice in two hours” conveys slightly more information than the reduced fraction.
Multiple worlds
Perhaps it is “dear old dualism” that causes our free-will illusion, as Bjarne Hellemann suggests (10 February, p 18). But perhaps there is more “philosophical confusion” in the common assumption that the subjective world, like the objective world, is a single entity.
It is obviously multiple. There are as many subjective worlds as there are subjects. Thus society as much as possible seeks both to tolerate subjective incompatibilities (between “the superior beings residing above the profane material world”, in Hellemann’s phrase, and within “belief in purely spiritual beings”) and simultaneously to make them conform to each other.
Surely we are justified in going further into dualism by recognising that the single science of the objective has, partially at least, taken the place of multiple religions in subjective worlds.
Mammal mia!
Alongside Jeff Hecht’s interesting news about Jurassic mammals, you say “mammals evolved from a group of reptiles called Dicynodonts” (3 February, p 35). This sentence contains two inaccuracies.
The dicynodonts were a side branch of the therapsids and did not give rise to mammals. The ancestors of mammals were therapsids named cynodonts.
Further, dicynodonts and cynodonts were not reptiles. The therapsids and pelycosaurs belonged to a group of vertebrates called the synapsids, which also includes mammals. These diverged from the early amniote vertebrates before the reptiles diversified. While many books call the therapsids and pelycosaurs “mammal-like reptiles”, a more accurate term is “non-mammalian synapsid”.
The editor writes:
鈥� Sorry, we did get our cynodonts and dicynodonts mixed up. But we decided that the clearest way to describe mammalian origins briefly is that they evolved from reptiles. Cynodonts, though not technically reptiles, were very reptilian indeed.
Dissident disagreement
I have recalculated your chart showing the total numbers of dissidents imprisoned for online activities by country (10 February, p 21). Adjusted for population, it looks different: the highest rate is for Libya, at about 0.18 per million population, followed by Syria (0.17), Tunisia (0.1), Vietnam (0.04), then China (0.03) and lastly Iran at 0.01.
I am no apologist for China, but you have to consider that the total number of people using the internet and the percentage of population using it are factors.
Don't bet on it
Stephen Oh claims that 70 per cent of 200 users of his Accuscore game predictor “said they were up ‘a little or a lot’ in their betting” (3 February, p 36). This statistic is virtually worthless.
How were the 200 users chosen? Presumably they were the respondents to a request sent to all users, in which case there is bias right away: only successful betters are likely to want to brag of their success. Losers will tend to ignore the survey.
Even if the 200 betters were a representative sample of all users, there would still likely be positive bias in the results. Some, perhaps many, respondents will make a quick, intuitive assessment of their success without actually going through their records and doing the calculations. Memory is notoriously unreliable and biased to the positive when making intuitive assessments.
There is further positive bias in that losers may lie about their results. Even some of the diligent respondents will gild the lily a bit. How often do gamblers tell you of their failures?
So we have no way of knowing how accurate the claim is, except to say that it almost certainly overstates the truth to a significant degree.
Look again at trauma
I was disappointed that in discussing post-traumatic stress disorder (PTSD) Laura Spinney dismissed eye movement desensitisation and reprocessing (EMDR) as if it was just slightly better than snake oil (3 February, p 40). There is an impressive body of robust research showing that this modern therapy for trauma is, in fact, effective. It is endorsed as such by many prestigious institutions worldwide, including the American Psychiatric Association in its practice guidelines for the treatment of PTSD, which gives EMDR the same status as cognitive behavioural therapy as an effective treatment for the symptoms of both acute and chronic PTSD.
The UK Department of Health and many other international health and governmental agencies have also endorsed EMDR. Documentation of the broad research base for this endorsement is readily available to any earnest reporter at the EMDR International Association website at .
Solar warming
You report the suggestion by Henrik Svensmark and others that changes in solar activity, which possibly result in changes in the level of cosmic radiation entering the atmosphere, may be partly to blame for global warming (10 February, p 9). It should be pointed out that solar activity shows a slight downward trend since the middle of the 20th century, as recorded by the international Wolf sunspot numbers. These cover the past 300 years and are the only reasonably reliable long-term measure.
Solar activity varies in approximately 11-year cycles; we are currently at a minimum. The peak of the most recent cycle was only 60 per cent as high as that in the 1950s. It was not as high as some of the peaks in the 1700s, when global temperatures were significantly lower than at present. These observations seem to be at variance with Svensmark’s thesis.
Enforced waste
Daniel Boyd has a point: our economy does depend on a throwaway society (10 February, p 18). It has, of course, been made before. George Bernard Shaw personified this in his 1929 play The Apple Cart as “Breakages, Limited”. And the classic 1951 Ealing comedy The Man in the White Suit relies on the horror of factory owner and union alike that Alec Guinness’s character might make a fabric that never wears out. We are lucky that we have so many more things to throw away now.
For the record
鈥� Jonathan Marks did not conduct research at the Hoover Institution, contrary to our report (10 February, p 13). He has seen a copy of documents archived at the institution. The documents are not classified but they will not be open for public inspection until 2010.
鈥� The story “Air rescue comes to Everest” (17 February, p 23) was truncated in a production error. It should conclude: “The helicopter will begin trial flights in the Himalayas in January 2008.”
鈥� In the article on “unnatural selection” (17 February, p 6) we accidentally added an “e” to Christian Roberge’s first name.
Look behind you!
A left-handed neutrino with mass will appear right-handed, Amanda Gefter writes, if you travel past it, turn around and look back at it (20 January, p 26). But turning around is forbidden by very special relativity.
I know I am out of my depth here, but surely if the spacecraft had a rear-facing observation window there would be no need for it to turn around.
Eat, drink and forget it
Lisa Melton’s article on the effects of acetaldehyde had a stark persuasive simplicity (10 February, p 31). By the end of the first page it was obvious I would have to severely limit my alcohol consumption in future. Acetaldehyde had been forming adducts willy-nilly with my muscle tissues, organs and DNA. No wonder I had been feeling so bad 鈥� and I thought it was only a cold.
By the end of the second page it became obvious that only complete abstinence would do. Even small quantities of alcohol were deadly. I could no longer rely upon the good old “French paradox” that had been keeping me healthy by the moderate and frequent sipping of red wine. It was starting to feel as though extreme lifestyle changes were going to be not only desirable but absolutely essential.
On the third page I found that acetaldehyde was produced not only by alcoholic drinks and smoking, but was also in the air, due to vehicle emissions, and in tea, coffee, yogurt, ripe fruit, bread and cheese. Yet worse, bacteria in my mouth and gut have been spewing the stuff out incessantly. So whilst riding the temperance wagon it seems I must also give my teeth a good brushing, recolonise my gut with friendly flora, avoid most foods and develop a habit for amino-acid chewing gum.
Alternatively, I found that after a few drinks I completely forgot about the perils of acetaldehyde.
Soul train
I was surprised to see that some 530 US congregations are celebrating Charles Darwin’s theory of evolution (10 February, p 4). I had always assumed that the Christian opposition to evolution had less to do with literal interpretation of the Bible and more with the major problem that confronts religious people who accept evolution. That is: at what point does the transition take place between animal and human being? Presumably there was an occasion when two animals without souls produced a human being with a soul.
I would be interested in any light that religiously minded readers can shed on this problem.
Advanced calendar
Andrew Robinson says that the Rosetta Stone was “dated 27 March 196 BC” (3 February, p 46). The people who carved out that stone were really clever!
The editor writes:
鈥� We could find neither a hieroglyphic nor an Ancient Egyptian Cursive font, and though we expect our readers are familiar with 2nd-century-BC dating systems, we decided to translate anyway.
Sausage r么le
Feedback mocks the brewer Batemans for suggesting that its vegan-friendly ale should accompany Lincolnshire sausages (3 February). But of course! The Redwood Wholefood Company makes vegan Lincolnshire-style sausages, sold in Holland & Barrett in the UK. Vegans can now enjoy caviar, ice cream, vegan pork pies, fishless fingers聽– even black pudding!
Population pressure
I was pleased to see that your graph showing different scenarios for climate change included population, though this was not followed up in the text (10 February, p 8). Considering that the human population has risen from 2.5 billion in 1945 to a staggering 6.5 billion today, it stands to reason that the extra millions must be contributing to global warming. Yet in all the talk generated by this debate there is no suggestion that population control or family planning and birth control might be a useful adjunct to carbon trading and airport taxes. Has anyone, I wonder, computed how much better off the planet would be now if world population had stabilised in the mid-20th century?
That said, surely climate per se is a function of planetary dynamics and solar activity.
The editor writes:
鈥� We receive many letters linking climate change and other issues to population. Population is expected to peak around 10 billion in mid-century. But its growth is almost entirely in the countries where per-capita emissions of most pollutants (including carbon dioxide) are least. So the effect of reducing population growth will depend entirely on which population you control. For example, stopping one child being born in the US will have about 20 times the effect of stopping an Indian child being born.