Letters: Hot blast
The waste heat generated by a 250 cc engine is more than adequate for
the purpose. Since internal combustion engines are generally somewhat less
than 50 per cent efficient, this means that around 10 kilowatts of waste
power is available for heating, much more than you get from your average
domestic electric heater. In conventional cars only a small proportion of
the waste heat is used for cabin heating, the bulk being removed via the
radiator.
Graeme Bushell Sydney, Australia
Letters: Fat facts
Figures from the recent Health Survey for England 1991 by the Office
of Population Censuses and Surveys are considerably more alarming than those
quoted by Helen Saul in her article ‘Fat is a pharmaceutical issue’ (24
July). This survey found that 13 per cent of adult men and 15 per cent of
adult women are obese with a total of 53 per cent of adult men and 44 per
cent of adult women overweight.
It is unlikely that many of the Health of the Nation targets will be
achieved unless the upward trend in obesity is abated. Although Saul makes
it clear that neither dieting nor diet pills alone are viable options for
controlling the nation’s weight problem, she gives no consideration as
to why so many people are becoming overweight and then obese.
Prevention is in itself a complex issue. It is necessary to increase
understanding and awareness of the problem and its effects on degenerative
diseases while not increasing the incidence of eating disorders and ‘yo-yo’
dieting among individuals with no or only a little excess body weight. In
addition, it is still uncertain whether obese ‘pear’ shaped individuals
are at as much risk as their ‘apple’ shaped counterparts.
Adequate nutrition and health education are vital, as are initiatives
such as product development (which, contrary to Saul’s article, can be more
than just producing fat substitutes). A concerted effort to increase physical
activity levels among all age groups is also essential. These strategies,
however, will be difficult to implement.
Fat is much more than just a pharmaceutical issue.
Adrienne Cullum British Nutrition Foundation London
Letters: Forced diet
The scandal is not that the food industry is failing to fortify its
products with folic acid but that they extract it (and many other vitamins)
in the first place. Not only do they sell impoverished bread and flour but
they try to tell us how good they are in replacing the few vitamins which
the law requires of them. If the wheat germ was not extracted in the first
place you would not have to worry about the folic acid masking the effects
of vitamin B12 deficiency because you would be getting B12 as well. There
is only one name for white bread . . . Mothers’ Ruin.
W. J. Agnew Southampton, Hampshire
Letters: Forced diet
Your readers may need to know that the drug Salazapyrin/Sufasalazine
is actively antagonistic to folic acid. This drug is frequently prescribed
for bowel disorders such as colitis and Crohn’s disease. My experience in
the early 1980s was that no warning is given by the GP, resulting in gradually
increasing stress and irritability over a period of weeks, leading to twitching,
irrationality and weakness. The cure was simple: high concentration B vitamins
twice daily.
I have no doubt at all that there are other drugs which affect folic
acid levels in the body. I have little confidence that the medical profession
will see fit to inform its patients of this fact. The only sensible course
of action must be for those patients taking drugs also to take a multi-vitamin
supplement each day, as a prophylactic.
Alan Thurley Clacton-on-Sea, Essex
Letters: Forced diet
As a pregnant woman very much aware of the link between folic acid and
neural tube defects, I was dismayed at the suggestion that folic acid should
be added to staple foods like bread (‘The great folic acid scandal’, 17
July). I feel the blanket imposition of any dietary supplement on the
whole population is inappropriate.
Do we know the long term effects of high doses of folic acid? It worries
me that people are suggesting yet more folic acid should be added to my
already relatively folic acid rich diet. I would draw comparisons with the
controversy over the fluoridation of water, with its possible side effects
of increased heart disease, cancer, etc. More recently the link has been
revealed between childhood cancer and the administration of vitamin K to
newborn babies for the prevention of haemorrhagic disease.
I can see the sense in targeting at-risk women, identified in your article
as those from deprived backgrounds. However, I can only see putting folic
acid in bread as a quick-fix solution. Surely most important is good health
education and addressing the issues of poverty and poor social and environmental
conditions. We need to ensure good general diet for those at risk not only
of neural tube defects but congenital abnormalities, premature birth and
poor child health. Perhaps then those people from deprived backgrounds could
make a real choice about what they eat, including folic acid supplements
if they choose.
Katie Rogers Ipswich, Suffolk
Letters: Corny question
Mixing ordinary kitchen cornflour with about an equal amount of water
to form a thick mixture reveals some interesting events. Pushing a spoon
in it slowly allows slow progress as the mixture acts like a liquid. However,
any attempt at quick motion of the spoon will result in no progress and
mixture acts like a solid. More dramatically, if you push the spoon down
into the mixture when pouring, the result is a solid stream.
Is this cornflour mixture smart?
Peter Naylor Leatherhead, Surrey
Letters: Not trainspotters
It didn’t all get scrapped – several coaches (I think a complete train)
survive forlornly on an isolated piece of track at the Crew Heritage Centre,
doing duty as the centre’s cafeteria. PS I do not carry a notebook.
Ian Sinclair Reepham, Norfolk
Letters: Not trainspotters
Feedback stated on 17 July:
‘Feedback’s man-at-the-end-of-the-platform-with-anorak-and-notebook
writes: ‘The APT was last spotted in 1986 being broken up in a scrapyard
in Doncaster’.’
Well, Feedback’s informant can’t have been a real trainspotter, or he
would have known that there is an APT (advanced passenger train) rusting
away at the back of the railway museum at York. PS I’m not a trainspotter.
R. J. F. Maines Jarrow, Tyne & Wear
Letters: Mind over muscle
Your correspondent F. G. Grisley (Letters, 3 July) would no doubt be
interested in the experiment carried out by Rodolfo Llinas with the help
of an artist friend, Arnold Gross. The artist was asked to draw a large
sketch of the face of a young woman, using mainly his elbow and shoulder
joints. He was then asked to draw a similar sketch, but on a much smaller
scale (about 1:10), with his drawing hand resting on the table (that is,
using finger movements alone). The small drawing was then photographically
enlarged and superimposed on the larger.
The accuracy of the degree of register between the two is remarkable.
It would seem that the ‘picture’ is complete in the mind of the artist,
and whichever muscles are used they merely transfer this picture to the
surface. One could postulate that if the artist had practised drawing with
his foot to acquire the required degree of control, the same picture would
result. If this is true of a drawing, which is ‘invented’ each time by the
artist, it should certainly be true of the far more ‘reflex’ process of
writing.
John Ralphs Ledbury, Herefordshire
Letters: Nice scientists
In his review of Jurassic Park, David Gale misses a couple of important
points (Review, 17 July). Jurassic Park may be limited in its degree of
scientific depth, but Gale is clearly forgetting the wide-ranging scientific
ability of Spielberg’s target audience – everyone from 7 to 70. The continuing
success of television programmes such as Tomorrow’s World is testament enough
to the validity of the so-called ‘popcorn science’ approach. To dismiss
the film on the grounds of lacking scientific meat is to denigrate the director’s
achievements, for he has reached a far greater audience than a dozen editions
of the aforementioned television programme ever could.
Secondly, this film is an excellent, but alas increasingly rare, example
of positive science fiction. Sure, the dinos go on the rampage – but for
once it is the scientists who save the day, rather than being the principal
perpetrators of the crime. The blame is placed firmly on the shoulders of
those who manipulate the technology.
The scientific community needs films like this to counteract the negative
propaganda of films like the hugely successful Terminator 2. Who can forget
Sarah Connor’s rant in that film against the scientific world: ‘You (scientists)
think you’re so creative. All you know how to create is death and destruction.’
In a world where it is all too easy to popularise anti-science, Jurassic
Park is a refreshing breath of fresh air, unpolluted by mad scientists who
want to rule the world.
Christian Graham Stafford
Letters: Hot blast
Illustration (omitted)
Clearly Norman Jenkins does not ride a motorcycle (Letters, 24 July).
If he did he would notice, every time he stopped at a traffic light, the
blast of heat rising from the engine. He would not be able to touch the
engine casings of even a 250 cc engine at idling speed, let alone the exhaust
pipes. There’s plenty of heat there. What it says about the efficiency of
the petrol engine is another matter.
John Humbach HQ NATO BFPO 49
Letters: Lateral challenge
I enjoyed reading your interesting article on ‘Maps that shape the world’
(3 July). However, I believe there is an error in the description of the
Lambert conic conformal projection on page 22. In the Lambert projection,
surface detail is projected onto a truncated cone arranged to intersect
with the Earth’s surface along two parallels of latitude. Normally these
parallels are towards the top and bottom third of the map. The article stated
that the cone intersects the earth along two ‘circles of longitude’. This
is clearly not possible.
Peter May Institution of Engineers, Australia Barton, ACT, Australia
Letters: Soil asset
Your article ‘Aerial tour of Britain’s changing landscape’ (This Week,
24 July) attributes the national soil databases to the Natural Environmental
Research Council. In fact, the one for England and Wales, LandIS, is managed
and developed by Cranfield’s Soil Survey and Land Research Centre (SSLRC)
with funding from the Ministry of Agriculture Fisheries and Food and that
for Scotland by the Macaulay Land Use Research Institute (MLURI) with funding
from the Scottish Office Agriculture and Fisheries Department.
The most comprehensive of their kind in Europe, these databases together
represent a major national asset, capable of rapid response on a wide range
of agricultural, environmental and geotechnical issues.
Peter Bullock and J. S. Gauld Cranfield Institute of Technology Bedford
Letters: Safety first
Referring to the Feedback article on the Safety Critical Systems Club
(10 July): The club is managed by the Institution of Electrical Engineers,
the British Computer Society, and the Centre for Software Reliability at
the University of Newcastle upon Tyne. The ‘systems’ referred to are software-based
systems in safety-critical applications – such as fly-by-wire aircraft,
railway signals and chemical plants.
The components of the systems discipline are drawn from a number of
domains, particularly safety engineering, software and systems engineering,
human factors and quality management. Academics are attempting to weave
these disciplines into new technologies, and there is a need both to bring
these new technologies to the attention of the system developers and to
transfer existing technologies between industries.
The objectives of the Safety Critical Systems Club are to facilitate
both technology transfer and the raising of awareness. It achieves these
objectives by a programme which includes a regular newsletter, seminars,
an annual symposium with published proceedings and many ad hoc initiatives.
Membership is open to all, and enquiries may be made to Mrs Atkinson, The
University, 20 Windsor Terrace, Newcastle upon Tyne, NE1 7RU; Tel: 091 212
4040.
Felix Redmill London
Letters: Better for coffins
I write to express my amazement that elm was, according to Calvin Hedley
(Letters, 3 July), used for the manufacture of long bows in the Hundred
Years’ War.
As woodworking craftsmen know full well, elm is of interlocked, short
and brittle grain, without any functional elasticity and easily given to
snapping off when thin lengths are bent. A more unsuitable wood for long
bows can hardly be imagined. Elm is very suitable for coffin boards, wooden
wheel bosses, the sides and floors of muck carts, wheelbarrows, large gate
posts, and traditional seat tops for country chairs and stools.
Traditionally, bows were made of English yew and there should not have
been any shortage of this. Ash would have made a relatively good substitute,
being noted for its flexibility, although not so resistant to compression.
Ash could have been cleaved from the log, whereas both elm and yew would
have to have been sawn over the pit – thus cutting right across the curly
grain of the elm especially.
We did lose the Hundred Years’ War did we not – just hanging on to Calais
by the skin of our teeth? Small wonder with elm bows.
Ray Heaton Solihull, West Midlands
Letters: Nearly killed
In the article by Mike Gaines on the ability of modern aircraft to generate
G forces sufficient to cause loss of consciousness in the pilot (‘Who’d
fly a superfighter?’ 10 July)), he says that ‘older fighters are just not
up to it.’ But my own experience as a pilot in the Royal Navy almost forty
years ago included an incident of loss of consciousness caused by G-forces,
which I only survived by a narrow margin.
The aircraft was a Hawker Seahawk, one of the first generation jet fighters
in British naval service. Despite its conventional configuration and limited
power it was capable of sustained turns of 8G, as measured by the cockpit
accelerometer, and we learned to fly at our personal limit by holding a
turn until vision narrowed and then easing back on the stick slightly.
The loss of consciousness incident occurred during simulated combat
at about twenty thousand feet. The flight of four aircraft was over the
Moray Firth in battle formation. As the number four in the flight it was
my job to scan the right rear quadrant for presumably hostile aircraft.
I noticed an aircraft crossing below and behind us and called a break right,
then rolled into a more than vertical turn, pulling through at what I expected
to be about an 8G diving turn.
In the next moment of consciousness I found myself about ten thousand
feet below the rest of the flight and on a divergent heading. I was flying
in level flight but the aircraft was rolling heavily back and forth about
ninety degrees. I looked down and noticed that my right hand was driving
the stick from one side of the cockpit to the other. In my confused state
I somewhat illogically tried to restrain my right hand by grasping it with
my left. At about this point my convulsions stopped and I returned to the
base without rejoining the flight.
Some months before this, a colleague had been killed in an accident
at another airfield. His aircraft had been observed to be executing violent
and random rolling manoeuvres at low altitude before impact. After my own
experience, I concluded that he was a victim of what is now called G-LOC.
In these years the navy had not yet adopted G-suits.
Loss of consciousness from G forces is a problem that has been around
for several decades, and was known to pilots of late generation piston engine
aircraft.
John Harris Palo Alto, California
Letters: Literary fix
I was disappointed to see the myth of Japan supposedly having the world’s
highest literacy rate given another airing (Comment, 10 July), and amazed
to see it backdated 130 years, which would place it well before the introduction
of universal education in that country, to a time when education was confined
to the (male) nobility and a few merchants.
Like many other myths about Japan (low inflation, low unemployment,
lifetime jobs, excellent education system, etc.) the claims about the literacy
level derive from very selective use of statistics, and simply do not hold
up when subjected to careful scrutiny.
The last thorough investigation of literacy levels in Japan took place
over 40 years ago. It categorised the reading skills of the populace into
10 groups, the last of which, labelled ‘illiterate’, consisted of people
who could not identify more than a few simple characters in one of the syllabaries.
In an amazing sleight of hand, the Education Ministry (Monbusho) declared
everyone else to be ‘literate’, and has been claiming the highest literacy
rates in the world ever since. Journalists and academics have fallen for
this line without hesitation. (Perhaps Western countries could solve their
literacy problems in a similar fashion; simply redefine literacy to mean
recognising four or more letters of the alphabet, and, hey presto, the problem
is gone).
Many Japanese simply do not believe the claims. One has only to look
at the cooking instructions on food packets, which are invariably supplemented
by drawings and cartoon characters, to suspect that the level of illiteracy
might be rather high. I recently heard of some privately sponsored adult
literacy classes in Tokyo, which were developed because of what was seen
to be a real problem. Needless to say, the sponsors were subjected to obstruction
and harassment from the authorities. After all, when the country has claimed
the highest literacy levels in the world, it is rather unpatriotic to act
as though this were not the case.
J. W. Breen Monash University Clayton, Australia
Letters: Right to rot
The analysis that hydroelectric power stations contribute as much CO2
to the greenhouse effect for the energy produced (due to the rotting of
organic material in the reservoirs) as the burning of fossil fuels is flawed
(In Brief, 24 July). All metabolic processes since the beginning of time
have produced CO2, but we do not have a runaway greenhouse effect
as this is part of a cycle where photosynthesis removes it from the atmosphere.
However, assuming the amount of biomass on the Earth’s surface remains constant,
the burning of fossil fuels causes an increased CO2 burden on
the planet – this is the root cause of any climactic change we may now be
experiencing.
Nigel Osborn Westbury-on-Trym, Bristol
* * *
Fred Pearce writes:
You have a point. But the balance is only maintained if new forests
and bogs replace the old. By flooding large areas, we reduce the amount
of biomass on the Earth’s surface.