Behind the fridge door
The easiest way to check if the fridge light is really going out when the door is closed is simply to close the door and leave the fridge running for a couple of hours (Feedback, 3 December). Then open the door and feel the lamp housing. If it is warm, the door switch needs adjusting. If the lamp housing is cold 鈥� all is well.
Incidentally, if the light is on permanently it will cost about an extra 拢40 a year in electricity bills and replacement bulbs, so it really is worth checking.
From Colin Gordon
Most mobile phones allow you to record short video clips. Start recording a video clip, put the phone in the fridge (lens side up) for a few seconds with the door closed, then remove from the fridge and play the clip.
I can only wonder how many people will record the inside of their fridge on reading this.
Glasgow, UK
Life in Lincolnshire
Further to the correspondence regarding the dynamism of Lincolnshire life (26 November, p 23), in his book The Pursuit Of Oblivion: A social history of drugs, Richard Davenport-Hines speculates that high levels of opiate use in 18th-century Lincolnshire were possibly due to life in the county being “so dull…that it was rarely worthwhile to remain fully conscious”. Little has changed, wallpaper exhibitions notwithstanding.
For the record
鈥� The Word article about junk DNA in 19 November issue (p 54) wrongly stated that the human genome contains a greater proportion of junk DNA than any other species. In fact, the ratio of junk DNA to protein-coding DNA is higher in certain other species, notably some amphibians, than it is in humans.
鈥� The citation in our recent article about faltering currents in the North Atlantic was incorrect (3 December, p 6). It should have been Nature, vol 438, p 655.
Right-handed selection
In your recent article on handedness, you mention that hand preference is widely supposed to be genetic, that humans are unusual in not having a 50-50 split of hand preference, and also the “right-shift factor” genes suggested by Marian Annett (5 November, p 36). I would like to suggest a contribution to this preference provided by simple selection pressure.
Due to the asymmetry of our digestive systems, gravity assists the digestive process of a baby lying on its left side, stomach or somewhere in between. The somewhere-in-between is very simply achieved by holding a baby with its neck and left shoulder in the crook of your left arm and your hand between its legs, so that the baby lies facing away from you and downwards with its chest and tummy along your forearm. This is a comfortable and secure hold for both baby and minder and will calm, in particular, a colicky baby.
A strongly right-handed mother will instinctively hold her baby in her left arm, leaving her dominant hand free for other tasks, so it would seem that right-handedness of a mother would be advantageous for both mother and baby. It wouldn’t be the first peculiar trait we have evolved as a result of the abnormally protracted infancy of our species.
Poor citizens of Rome
Poor, poor citizens (and beagles) of Rome, soon to be subjected to the dark skies policy (19 November, p 4). It’s probably not politically correct to say so, but I don’t appreciate Tucson’s dark skies, and I would venture to say that my beagle, Ike, doesn’t either.
We live in midtown Tucson and when we first came here, I thought that the reason blocks of my neighbourhood were pitch black was because this is a poor city that can’t afford to power street lamps. We moved here from Alexandria, Virginia, where I walked Ike in the dark winter evenings and at bedtime without a second thought, because there was a street lamp on every corner and a bright supermarket parking lot to put our minds at ease. In Tucson I am not at ease with after-dark walks because I can’t see the faces, or any other aspect, of people around me. Poor Ike — he just gets a quick sniff of the perimeter before bed now.
Nominative palindromy
Reading your piece about nominative palindromy reminded me of when I was a student at Cranfield University (Feedback, 3 December). One of the lecturers, Joe Nellis, told us about his previous post, where his office was next door to that of a Joan Ellis. No doubt this kept the receptionist highly amused when visitors called to see one of them.
From Hugh Newbury
There’s a possible extension to nominative palindromy. There is a China specialist in Washington DC named Bates Gill — you may Google for him. This is more than just a case of nominative palindromy with Bill Gates. I would call it nominative Spoonerpalindromy.
Dorchester, Dorset, UK
Immoral traits
Dan Jones’s article omits two important aspects of the moral equation, which arguably are the cause of the worst of the immoral acts we witness worldwide (26 November, p 34).
One is the identification with a group which treats outsiders as less deserving than those within the group, and the other is conformity, which is arguably the most fundamental of all human behaviours. The combination of these two social traits has led to the worst of human atrocities witnessed in the last century, if not through our entire history.
From Gwydion Williams
Am I the only person to notice that if you actually followed the “moral” advice in the problem 鈥� pitching an innocent man to certain death so as to save five other lives 鈥� you would be guilty of murder under English law and under pretty well any system of law, I would assume.
You can’t have a human society unless people are strongly inhibited from killing each other, regardless of circumstances.
Peterborough, Cambridgeshire, UK
Theory or law?
Lawrence Krauss believes that scientists should not use the word “theory” to describe speculative or unproven ideas, as in “string theory” or “inflationary theory”, since this allows proponents of intelligent design to dismiss evolution as “just another theory” (3 December, p 23). But his suggestion that scientists should define the word differently from common usage is surely the wrong approach.
There is another stronger word already used to describe theories that have stood the test of time, particularly if the theory can be expressed relatively simply. The word is “law” 鈥� as in the laws of thermodynamics, Boyle’s law, Newton’s law of gravity, and so on. Surely Darwin’s “theory” of evolution falls comprehensively into this category.
Intelligent design may be a theory, but it can hardly qualify as a law.
Show me the aliens
Stephen Wolfram states that we could simulate alien society here on Earth, and from that derive all knowledge that an alien could possess (26 November, p 30). But I think he is missing the point. As an active participant in the SETI@Home project over the past five years, I can attest to having no real interest in the knowledge an alien could pass on to us. Here are my key questions: are extraterrestrials out there, where are they, and what are they?
From Billy Huang
Wolfram seems to believe that computer programs might contain the fount of all knowledge. I agree with him. However, I believe we will never be able to extract this knowledge.
If we are given an infinite list of combinations, yes, Hamlet will be there, and also the theory of relativity. But one will also find infinitely many alternate versions of these works. Unless we know exactly what we are looking for, we cannot extract or find the right version. In the infinite world, there is an infinitesimally small possibility of finding what you are looking for.
Edinburgh, UK
From Andrew Thewlis
It seems clear, even at this early stage, that the end result of searching for useful algorithms would take seven-and-a-half million years and yield the answer “42”.
Stockport, Greater Manchester, UK
Where is the heat?
Fred Pearce notes the warmer temperatures enjoyed by Europe as a result of the oceanic currents flowing from the tropics past our shores (3 December, p 6). The article also leads one to believe that a shutdown in the existing current may prompt a temperature drop in Europe, in the order of 5 to 10 掳C.
If the existing current does stop, one unanswered question must surely be, what will happen to the heat energy now carried out of the tropics? As a layman, I can see only three options: the tropics will increase in temperature; an alternative current will develop in the oceans that will shunt the heat away; or the atmosphere will become more turbulent as the convection currents (Hadley cells) increase over time, again shunting heat away from the tropics.
Whatever the mechanism, I suggest that the impact will be much more global than the article suggests.
Death by diet?
The controversy over the finding that overweight people have a lower risk of dying than either obese people or those with a “normal” weight is an example of everyone looking in the wrong direction (26 November, p 38). Instead of asking “is the upper limit of ‘normal’ body mass index wrong?”, we should be looking at the lower limit.
When the US National Health and Nutrition Examination Survey first proposed BMI categories, the lowest figure for the normal range was set at 19.1 for women and 20.7 for men. Arbitrarily, the World Health Organization decided on 18.5 鈥� lower than either value 鈥� for both sexes.
This is absurdly low. I am a 1.75-metre male, and a BMI of 18.5 would have me weighing 55 kilograms at which point my risk of death would be acute. At my actual weight of 68 kilograms my BMI is 22 and I’m lean enough that you can count my ribs.
The probable explanation for Flegal’s results is that there are many morbidly underweight people in the supposedly normal sample.
As for Thorkild S酶rensen’s finding that people who successfully lose weight have a higher risk of dying sooner, the question is: is it the weight loss or the diet that is killing them? Several diets on the market may well carry health risks.
From Chris Elliott
Your editorial describes BMI as a crude instrument, and in your feature you show how to calculate it. Surely this method of calculation is grossly unfair to tall people.
I am 1.8 metres tall. The calculation assumes that we are two-dimensional beings, since a person’s mass is divided by the square of their height not the cube, so tall people have to be thinner in proportion than short people.
This is well illustrated by calculating the BMI for members of last year’s University of Oxford boat race crew (available at ). Most of the rowers who are tall come out as overweight, while the cox is underweight.
Ampthill, Bedfordshire, UK
From John Lee
James Kingsland’s sensible article contains an example of a type of arrogance which has no place in scientific discourse. One of the scientists interviewed feels that “there is no plausible biological mechanism that could make being overweight a benefit” and that therefore “this ought to be the final nail in the coffin” for the idea.
This is, of course, a non-scientific argument. The fact that a mechanism is not obvious at the time can never be used to negate a finding. The history of science is full of people kicking themselves for doing just that 鈥� and missing an opportunity to discover something new.
For the record, there are plausible mechanisms. For example, fat depots are rapidly mobilised in response to infection to provide fatty acids for membranes and other components of white blood cells. So it is plausible (though not proven) that depleted fat stores might impair responses to infection. There is plenty more to come in this debate.
Rotherham, South Yorkshire, UK
Crop testing
When expressed in transgenic peas, an innocuous bean protein elicits immune reactions in mice, reviving concerns about the allergenic potential of genetically modified foods (26 November, p 3 and p 5). These “surprising results” from researchers in Australia raise several intriguing questions.
Should regulators require the use of animal models? Allergenicity assessments of transgenic proteins in GM crops are usually limited to in vitro tests of digestive stability, database searches for sequence similarities to known allergens, and in some cases a heat stability test. While certainly cheap and convenient for GM crop developers, such tests provide no direct immunological information and cannot rule out allergenic proteins. Both the BALB/c mouse strain used in the Australian pea study and the brown Norway rat have shown promise as predictors of human allergic response.
Also, at present, all testing is performed on a bacterial surrogate of the protein, rather than that produced by the plant. GM crop developers complain that it is too inconvenient to extract sufficient quantities of transgenic protein from their plant. But if peas and beans 鈥� both legumes 鈥� can generate immunologically distinct proteins from the same gene, surely the same is true of bacterium and plant. Thus, results of testing on bacterial surrogates may not reflect the toxic or allergenic profile of the in planta protein people are exposed to.
Other factors also argue against use of bacterial surrogates. For example, allergenic proteins are often glycosylated, and plant glycosylation patterns have been implicated in allergenicity. Bacteria, in contrast, seldom glycosylate proteins.
Finally, perhaps regulators should demand full sequencing of the transgenic proteins in plants. At present, the standard practice is to sequence just 5 to 25 amino acids at the N-terminal as a demonstration of “identity”, even if the putative protein is 600-plus residues long. Since the transformation process 鈥� the insertion of foreign DNA to a cell 鈥� can be sloppy and even point mutations can transform an innocuous protein into an immunogenic/aggregating one, it is unclear why this basic information is not required.
The editor writes:
鈥� These are excellent suggestions, and perhaps such a test regime should also be applied to new conventionally bred varieties. These can sometimes generate unexpected allergens or toxins too. For example, a potato variety called Lenape was withdrawn from the US market in the 1960s when it was found to contain dangerously high levels of potato toxins called solanidine glycosides. And in the mid-1980s, American growers abandoned a variety of celery because it contained high levels of psoralens 鈥� chemicals which become irritants when activated by sunlight. Workers picking the celery developed skin rashes. Psoralens also occur in parsnips, and have been known to cause rashes through skin contact.