Letters : Flintstone first
Manchester
I read with amusement Barbara Moran’s comments on the robot walking downhill
using passive dynamics (“Back to basics”, 7 September, p 32). This is a very
good description of a toy I had when young (a lot longer ago than 1989) in which
Barney Rubble and Fred Flintstone, joined at the waist, would scuttle down a
ramp, with their legs swinging forward in turn.
Maybe scientists should ask toy companies to get involved in manufacturing
other robots or satellites?
Letters : Not so nutty
Killiney, Co. Dublin, Ireland
Regarding your amazement that the makers of Mini Shredded Wheat should find
it necessary to advise customers on the possible presence of nuts in a product
that describes itself as “100 per cent whole wheat”: it is crazy, but not for
the reason you put forward (Feedback, 7 September).
My son has a nut allergy, among others, so I have been reading labels for
years. However, I learnt only recently (via a list of gluten-free foods on the
Net) that while manufacturers must list all of the ingredients in a product,
they don’t need to specify any details of the packaging or production process.
So even if a brand of, say, chewing gum is gluten-free, the conveyor belt at the
manufacturers might be dusted with flour.
Buckwheat flakes are naturally gluten-free, but if they are packed on
machinery that is also used for wheat flakes, there will be problems for
coeliacs. For cereals, plain Shredded Wheat might be packed on the same line as
a honey nut cereal, thus raising the very real possibility of
cross-contamination.
It’s easier to print a disclaimer than to modify a process. There has been
quite a vigorous debate recently on the Net over the merits of more stringent
labelling legislation, but many people with allergies feel that it would be
better simply to have a wider range of products we can actually eat.
Letters : Heed the warning
Address not supplied
Regarding manufacturers’ daft warnings, the following may be of interest to
you, as it shows you were wrong to criticise the warning on the antitheft device
mentioned (Feedback, 31 August). The basic instruction for these car locks is to
hook them round the clutch and the steering wheel鈥攂ut not the brake and
the steering wheel, as a colleague of mine did recently.
The colleague, Bill, went to a football match with three friends, all of whom
were off-duty policemen. Bill duly parked the car in the cinder-covered car
park, but unwisely fitted his lock between the brake and the steering wheel. The
group went to see the match, enjoyed it and left at the end for a pint.
From the hostelry they got back to the car, by which time it was dark. They
got in quickly as it was raining hard. Bill started the car, engaged gear and
shot out of the space. He then attempted to turn smartly left to clear the car
parked opposite, found that he could not, and attempted to brake sharply, only
to find that he could not do that either. Frantic heaving on the handbrake
locked the rear wheels, allowing the car to slide gently over the cinders into
one of the other parked cars.
If you do not want unpleasant things to happen, you should obviously heed the
warning to remove the device before attempting to drive. However, perhaps the
manufacturers are themselves in error, in that they have not made the warning
illuminated at night (and preferably flashing as well).
Letters : . . .
Liverpool
As an ex car thief, may I add a note of warning about manual crook
locks. If a car owner puts the hook from the foot brake to the steering wheel,
there is a lot less play than with the other pedals.
The foot brake depresses only slightly, whereas the clutch and accelerator go
right down to the floor, allowing the car thief to bend the wheel some distance.
When releasing the clutch or accelerator after bending the wheel downwards, the
lock can sometimes be easily unhooked.
Most car thieves glance straight at the pedals to see which one the lock is
on and if it can be taken off easily. A car with a lock attached to the foot
brake is usually given a miss.
Letters : Smell of sex
Las Vegas, Nevada
I was delighted to see your report on the study by Astrid Jutte about men’s
response to the scent of ovulating women (New 杏吧原创, Science, 7
September, p 16).
This research confirms speculation by Harold Persky as described in
Psychoendocrinology of Human Sexual Behaviour (Praeger, London, 1987) on
page 108: ” . . . a form of communication exists between the two partners
whereby the female informs the male that she has ovulated and he responds, like
the dominant rhesus monkey, with an increase in his testosterone level
facilitating his entire sexual response cycle.”
Of particular note, however, is that you then state: “[Jutte] was unable to
prove that ovulation affects [men’s] attraction to women.” A cross-species
comparison in the light of data on the testosterone increase and general
acceptance of the causal relationship between testosterone and male sexual
behaviour may not be proof that the pheromones of women affect the behaviour of
men. But you might well have added that if Jutte’s findings are not proof, there
will be no proof.
As is typical when a researcher attempts to link biologically relevant data
to human behaviour, all that can be done is to reflect upon an animal model of
behaviour. According to some people, animal models of behaviour should not be
applied to human behaviour. Thus, whether human pheromones influence human
behaviour remains a mystery.
Letters : No food fix
Leighton Buzzard, Bedfordshire
David Hall is the one who has the connection between biodiversity and hunger
wrong (Letters, 7 September, p 48). The principal cause of the Irish potato
famine was the blight and, as he says, the effects of the blight were
exacerbated by the British occupying forces. The point he misses is that had the
Irish grown several dozen varieties of potato, there would have been less
starvation.
It is also true that modern high-yielding varieties have fed the world’s
expanding population and that loss of biodiversity has not yet caused mass
starvation. But the loss of old varieties and original wild relatives of modern
farmed crops severely reduces the gene pool that Hall agrees we will need to
breed new varieties.
Further, the use of genetic engineering to move genes from one species into
another is clearly financially attractive in the short term. But in the long
term, where will our food supplies be when everybody grows the same, or similar,
engineered varieties and the bugs finally evolve around the new hurdles that we
have erected鈥攁s they will? The history of rice varieties developed in the
Philippines, for instance, shows that every time a “super rice” comes along, a
“super bug” appears and devastates the crop.
There is no quick fix that will guarantee food security. Our future food
supplies are best safeguarded by keeping, and growing, the broadest selection of
all our food crops so that we can continually fine-tune what we grow to suit
local circumstances. Any gardener will tell David Hall that different varieties
respond to environmental challenges in different ways.
Letters : Towering turbos
Cheltenham, Gloucestershire
I am very surprised that the US physicist Melvin Prueitt has been able to
obtain patents on his energy-producing towers (This Week, 31 August, p 7). They
bear a remarkable similarity to the Carson towers devised by the American
physicist Philip Carson in 1975.
Carson suggested giant towers to make cheap electricity from falling air. He
suggested that a hollow tube at least 1 kilometre long should be stood on end to
form the tower. Then, tonnes of sea water should be pumped up it and sprayed
into its top. The water would evaporate and thus cool the air. Cold air falls,
and the cooled air would fall down the tube at 60 kilometres per hour. Wind
turbines mounted at the bottom of the tube could then produce a large,
controllable amount of constant electricity.
In theory, Carson towers (sometimes called “energy towers”) could supply all
the world’s electricity needs several times over. And the electricity would be
very cheap, costing about a third of the cost of electricity from coal-fired
power stations. Laboratory studies show that they should work. The Technion in
Haifa has produced detailed designs for a 50-megawatt prototype Carson tower
which would only be 200 metres tall.
But this would only demonstrate the principles. Proving the economics of the
process would require construction of a tower at least 900 metres tall, and that
would cost at least $650 million. Nobody is yet willing to take that
gamble. The only real difference between Carson towers and Prueitt towers seems
to be their height.
Letters : . . .
Cambridge
I have read about such chimneys before. I would refer the reader to the
science fiction short story, “Shortsack”, by Walt and Leigh Richmond. This story
has many similarities to your article.
Was the patent office granting Prueitt’s patents aware of this? The copyright
date is 1964. It would seem to place much of this invention in the public domain
long ago.
Letters : More is worse
Darmstadt, Germany
“A thousand channels in every home” (10 August, p 32)? Maybe, but what are
they going to show?
Given that the overwhelming majority of TV is garbage, who wants a hundred
times more crap than we already have? Count me out.
Britain has a very high standard of TV programmes in comparison to most
places. Here in Germany, thirty or so channels come down the line, mainly
garbage.
New programmes cost money. Good new programmes need good ideas and good
producers, and cost more money. So companies end up just recycling the same old
stuff. One thousand channels of movie reruns? I can hardly wait.
Letters : Burning cows
Cambridge
Dead cows may not belch or fart methane (This Week, 31 August, p 5), but if
the majority of carcasses from the cull are disposed of by incineration, for
example in power stations (In Brief, 22 June, p 11), then the effect of the BSE
crisis in reducing Britain’s greenhouse gas emissions may not be as great as has
been suggested. Estimates of the number of cattle which should be culled in
order to eradicate BSE vary widely but, on a cow-for-cow basis, carcass
incineration of an average sized beast comprising 18 per cent carbon may yield
over 160 000 litres of carbon dioxide. This is roughly equivalent to the amount
produced through respiration by a single animal in a month.
It is the long term that is important for global warming but, in the short
term, incineration of carcasses from the BSE cull could provide another reason
for beleaguered British beef farmers to feel hot under the collar.
Letters : Crystal credit
Switzerland
The glueball candidate called fo(1500) is not a forgotten particle originally
classified as a vibrating quark-antiquark pair (New 杏吧原创, Science,
17 August, p 18). It was established in 1994 as a new particle by a team of 70
experimental physicists (the Crystal Barrel Collaboration) which studies the
annihilation of slow antiprotons in collisions with protons at the Low Energy
Antiproton Ring at CERN.
Admittedly, a signal had been spotted before, but the existence of this state
and its properties (mass, spin, lifetime) have been firmly established by the
Crystal Barrel Collaboration, which deserves full credit for this discovery.
These measurements, rather than data archived across the world, have led Frank
Close at the Rutherford Appleton Laboratory in Britain and myself to conclude
that fo(1500) matches the theoretical description of a glueball.
Letters : All in the mind
Coln St Aldwyns, Gloucestershire
Marcus Chown asks, “Are we killing astronomy?” (24 August, p 28). The
argument is that astronomers are being made redundant because the “window”
through which they look into the sky is being blocked by interference caused by
“street lights, satellites and CFCs”.
I would like to reply with the view expressed by Plato in The
Republic, where Glauco asks Socrates what he meant by saying that astronomy
ought to be learnt on a system quite different from the existing one. Socrates
replies: “The heavens tapestried with stars are admittedly the most beautiful
and exact of visible things, but much inferior to the mathematical elements of
motion which they exhibit.”
After amplifying this, he concludes by saying: “We shall pursue astronomy
like geometry by the use of problems, but we shall leave the things in the sky
alone, if we really intend to get hold of astronomy.”
His idea is that geometry deals with diagrams which represent permanent
relations in space and that, although no diagram is ever actually correct, it
stands for a diagram not drawn by the hand or seen by the eye, which is
perfectly exact and indestructible. So if astronomers wish to save themselves
from being “killed”, perhaps they should stop looking up at the stars, but look
down and ask themselves this question. If the “vital information needed to
understand the problems besetting the Earth may be found elsewhere in the
Universe”, why not also in our minds?
Perhaps we should all be asking ourselves that question.
Letters : . . .
Alicante, Spain
Marcus Chown correctly states that an observatory on the far side of the Moon
would be expensive, but goes on to claim that dust stirred up during
construction work could take years to settle.
But haven’t we all seen how the dust kicked up by the Apollo astronauts’
boots fell like lead shot? Surely dust clouds require an appreciable
atmosphere.
Those who followed the Apollo missions will also recall the total
communications blackout experienced as each spacecraft travelled behind the
Moon, a striking demonstration that the far side of |the Moon is perhaps the
best place in the Universe to carry out radio astronomy in the more distant
future.
Letters : Spot on
Portsmouth, Hampshire
John Chapman’s allegations that the construction industry is incapable of
precision in dimensional control cannot go unanswered (Letters, 31 August, p
47).
I have built a number of structures to a high degree of precision. In 1981 I
built a structure with a similar size and shape to an Olympic swimming
pool鈥攖he docking facility for the Isle of Wight car ferry in Portsmouth.
The specification called for a tolerance between hinge and bearing plates, which
were at each end of the structure, of plus or minus 10 millimetres. The
tolerance was in line, level and elevation. We achieved a dimensional envelope
of minus 2 and plus 5 millimetres with cast-in-situ construction. This then
allowed second-fixing of the equipment to a much higher precision. The
construction did, however, tax our skill and patience.
When considering the dimensional accuracy of an Olympic pool, I would have
thought that the main source of error would be temperature effects and material
shrinkage. I presume that the Olympic committee has a measurement service to
establish the start and finish immediately prior to any event, thus allowing
precision in timing to be valid.
Letters : Gone with the guru
Carlton Colville, Suffolk
Further to your piece on “guru meditation” (Feedback,7 September) on early
Amiga computers, the story was not quite complete. The #xxxxxx.yyyyyyy series of
numbers was supposed to give initiates some clue as to what had caused the crash
and where. However, one set of numbers, when translated from the HEX into ASCII
letters, spelt HELP.
It also added a new word to the language, for whenever anything went wrong in
our house my young son would say: “It’s just guru’d, Dad!”