Letters : Now you see it…
Australian science has suffered a serious setback with the federal
government’s decision to decline an invitation for Australian membership of the
European Southern Observatory (ESO) and take part in the building of the world’s
largest telescope鈥攖he Very Large Telescope (VLT). Australia will miss out
on a crucial element of the future for optical and infra-red astronomy
(Editorial, 18 May, p 3 and This Week, 18 May, p 7).
In a recent review sponsored by the Academy of Science, membership of ESO and
the VLT project was recommended as the top priority initiative for advancing
Australian astronomy into the 21st century. ESO membership would provide access
to facilities which complement Australia’s existing world-class telescopes and
provide other benefits to all Australian astronomers. It also offers new
opportunities for Australian industry, particularly those in high technology
areas, to engage in major collaborations with European partners.
Now the Minister for Science, Peter McGauran, has said that while the case
for membership is strong, the government cannot find the funds. Hard economic
times require tough decisions, but we believe that the government should look to
its winners to support and astronomy has proved itself as our best performing
science, producing the most impact internationally.
Without guaranteed access to telescopes like the VLT, Australia’s enviable
international reputation in astronomy, built by hard work over many decades,
will be a thing of the past.
Letters : Magnificent machine
Cambridge
Apart from Condom Nautilus, the methods of human-powered underwater
propulsion described in “Wacky Races” (11 May, p 38) are extremely conventional.
It is surprising that no mention is made of a remarkable British invention which
showed there can be more to it than pedals, paddles and propellers.
The Aqueon, manufactured by Unitex, Knaresborough, Yorkshire, was powered by
the synchronised action of flexion and extension of both legs operating a pair
of wings that went up and down like ailerons. It was claimed to have a
propulsion efficiency of 86 per cent with a possible mean static thrust
exceeding 95 lb, and speeds in excess of 5.5 knots (10 kph) as well as an
ability to maintain an average speed of some 2.5 knots over considerable
distances of even some 30 kilometres.
Although I am a comparatively weak swimmer I was amazed at the sense of power
it gave, more like flying than swimming. It had the ability to overcome tides
and currents and had great potential for rescue work. The only problem was that
it could not go into reverse, and all I ever got was water down my snorkel
tube.
It struck me as having enormous possibilities for development鈥攆or
example, side-by-side models for two people or arm-powered models for the
lower-limb handicapped, but for some reason it all came to nothing. My Aqueon
now lies in the attic for lack of constant replacements for the rubber band
needed in the transmission. And who knows what happened to Unitex?
Letters : Centre that glitters
Bristol
In “Caught in the goldrush” (11 May, p 14), Fred Pearce implied that RTZ
“ran” the Exploratory hands-on science centre in Bristol. This is incorrect. The
Exploratory is an independent educational charity dedicated to helping the
public understanding of science, particularly with children. We receive support
from many companies throughout Britain. RTZ sponsored our chemistry programme
from 1990 to 1993 and we are most grateful for their contribution to our work at
that time.
Letters : . . .
Corsham, Wiltshire
The article is illustrated with photographs of AP mines and a bomblet of
Italian, US and probably Soviet origin. The most abominable aspect of these
mines is that each device contains its own triggering mechanism鈥攗nlike the
Claymore. Each mine is designed to lie and wait鈥攁nd, being well designed and
manufactured, will probably do so for a hundred years鈥攗ntil someone treads
on it. I occasionally tread among them, and do so with my fingers crossed, if
not my legs.
The Claymore is no less lethal鈥攔ather more so, in fact鈥攂ut it is
directional and designed to be fired either by the user, lying in wait, or by
the victim(s) but via a separate triggering mechanism such as tripwire.
Since neither the operator nor a tripwire across a road will lie in wait for
decades after a war is over, it is perhaps best to classify such devices as the
Claymore with other weapons such as rifles or mortar bombs, which are much more
target-specific and readily and safely removable. Those AP mines designed to be
buried or scattered are perhaps best regarded as an extreme form of
environmental pollutant which any damned fool can spread but which poison the
land for generations.
Letters : . . .
Warwick
Your article failed to mention that millimetre-wave cameras, IR sensors,
ultra wideband radio, NQR or any eventual combination as “sensor fusion”, will
make little difference in most mined areas of the world.
While of use to the military in the developed world, high tech solutions do
nothing to empower indigenous mine clearers in, for example, rural Africa (the
most mined continent in the world). They will be too expensive to buy, too
complicated to use and too costly to maintain. Bear in mind that the landmine
problem will be around for decades, and that the poorer people in post-conflict
countries cannot rely on a bottomless pit of foreign money and expertise.
That said, you might expect me to support Stephen Salter’s proposed
mechanical mine clearance device called the Dervish (Technology, 9 March, p 25).
I do, with one reservation. The Dervish may not be of much use in minefields
that were laid a long time ago (and some of the African wars have gone on for
decades). Mined agricultural land can quickly revert to jungle or bush.
Letters : Monkey madness
Daly City, California
NASA’s Bion project should and does outrage many in the scientific community,
not just “animal activists” (This Week, 4 May, p 5).
The rationale for Bion is that NASA is concerned about the effects of
weightlessness on astronauts on prolonged space flights, especially loss of
muscle mass and strength reduction in bone density.
NASA claims that the loss of muscle mass can be elucidated by implanting
needle electrodes in the muscle mass of monkeys, who are fully immobilised in
restraint chairs during a 14-day space flight. The problem with this is that
immobility itself produces muscle weakness and atrophy, quite a bit in fact,
even within two weeks. I see this in my practice in patients on bed-rest, and
this problem has already been studied in humans with far more sophisticated
methods, including muscle biopsy, than would be used in Bion.
The data generated by Bion, moreover, would be worse than redundant; it would
be misleading. Every aspect of muscle physiology would be altered by the
monkeys’ complete immobility so that the data would reflect chiefly the effects
of disuse weakness and atrophy rather than of weightlessness.
Will this project appreciably contribute to the health of astronauts on
future space missions? Having reviewed the Bion protocols, my opinion is that it
will not. The rationale for Bion is nowhere near sufficient to justify its
continuation, let alone its $33.2 million price tag. NASA should simply
end this set of experiments, which are essentially crude holdovers from the
early phase of the space programme.
Letters : Sperm and diet
Ammanford, Carmarthen
Niels Skakkebaek’s hypothesis that rising levels of oestrogen-like compounds
in our environment suppress sperm counts should not be expected to account for
all the observations (This Week, 11 May, p 10). If Skakkebaek is right that
sperm counts are going down, selenium deficiency could be another important
factor, and may help account for the geographical distribution and time
variability. It’s well known that selenium deficiency impairs spermatogenesis
and reduces sperm viability.
Selenium soil levels are low in Britain and much of northern Europe.
Consequently, the levels in our bread, milk and meat are inadequate. Our
selenium intake fell from 60 micrograms per day in the late 1970s to 36
micrograms a day in one study in 1994, reflecting a switch in our source of
flour from Canadian selenium-rich wheat to low-selenium homegrown or European
wheat.
Finnish soils are notoriously low in available selenium and the Finns’
mid-1970s intake was 25 micrograms of selenium a day. This was dramatically
changed in 1984 by the Finnish government’s decision that every bag of
fertiliser should supply a certain level of selenium per hectare.
The levels in cereals, meat and dairy products soared, and human intake rose
to 90 micrograms a day, conferring protection against heart disease. It can be
deduced that adequate dietary selenium may account for the high sperm count
recorded for Finnish men.
Variations in sperm count between states in the US may well reflect the
source of flour and other foods, and also losses in processing. The overall high
sperm count in the years 1976 to 1977 should be examined to see whether they
reflect a continent-wide drought: drought would oxidise selenite to the more
available selenate and increase selenium uptake by the crops.
These considerations should in no way detract from Skakkebaek’s hypothesis.
Selenium deficiency may be a major, minor or contributory cause, depending on
the circumstances.
Letters : Up in smoke
Salisbury
Kurt Kleiner reports that 88 per cent of Americans have traces of nicotine in
their blood, supposedly caused by exposure to environmental tobacco smoke and
measured by cotinine analysis (This Week, 4 May, p 9).
The use of cotinine as a measure of such exposure is open to doubt. In the
New England Journal of Science (August 1993), Edward Domino reported that one
microgram of nicotine would be absorbed by consuming the following amounts of
common vegetables: 8 ounces of ripe tomatoes, 2.5 oz of green tomatoes, 5 oz of
potatoes, 1.5 oz of pur茅ed potatoes, 2 oz of cauliflower, 0.25 oz of
aubergine.
Ruth Etzel has also questioned the reliability of cotinine as an indicator of
exposure (Preventive Medicine, vol 19, 1990), noting that high levels
of cotinine had been found in people not exposed to tobacco smoke, a finding
noted in the present work.
It is also worth noting that the 1993 report by the US Environmental
Protection Agency quoted by Kleiner caused a furore amongst American scientists
because of its highly selective use of data. Its findings were based on 11
American studies while ignoring some 19 other studies not of US origin, it used
meta-analysis which ignored virtually all accepted rules for combining results
in such studies and it used 90 per cent confidence limits rather the generally
accepted 95 per cent limits which, incidentally, would have shown no significant
risk.
Similarly, the work on chickens was criticised because of the unrealistically
high exposure levels, some of the early work being equivalent to a daily
consumption of millions of cigarettes a day.
It is stated that the new study shows that almost everyone is exposed to
cigarette smoke every day. This is difficult to reconcile with the statement
that more than half of the people studied neither work nor live with
smokers.
In 1990, an American epidemiologist admitted: “Yes, it’s rotten science, but
it’s a worthy cause.” Six years later, things have hardly changed.
Letters : Heavy duty
Kenilworth, Warwickshire
There is too much killing, and too little thought, in “The science of
killing” (4 May, p 37).
The Claymore mine is an infantry weapon. That means it must be portable.
Seven hundred balls, each weighing 150 grammes, tot up to more than 100
kilograms. Allowing for explosive and casing, that suggests an all-in weight of
perhaps 150 kilograms. The US evidently bred mighty strong infantrymen in the
1950s, a period when the average rifle or machinegun bullet weighed half an
ounce鈥攍ess than 15 grams (they have become lighter since).
The whole mine debate is bedevilled by humanitarians who will swallow the
most implausible assertions without undertaking even elementary arithmetic. The
Valdara mine on your cover is a case in point. It has recently figured in bank
advertisements which give it the ability to cut all bystanders to pieces at a
distance where the probability is ten to one against it even touching them.
Weapons designers do not maximise killing potential. Their aim is to maximise
incapacitation. A corpse can be forgotten, but a seriously injured man
incapacitates two or more others while he is carried from the field and is
nursed as he recovers. Killing him is counterproductive. That is why minefields
leave so many footless farmers. Anti-personnel mines are not intended to
kill.