Letters : Seek and destroy
rhld2@cam.ac.uk
Ian Anderson’s report of a novel method of spotting landmines
(This Week, 2 August, p 13)
interests me very much, as I am the appeal organiser for the
Dervish mine detonation project (“Dervish dances through killing fields”, 9
March 1996, p 25).
My response is simple. Just as one needs a set of clubs to play golf, so
those engaged in clearing landmines require a battery of methods in order to rid
the world of this scourge. The machine we promote, the Dervish, destroys
landmines in the process of detecting them, and so prevents them from being
lifted, made safe, and then sold on for laying elsewhere鈥攁s happened with
many landmines cleared from Kuwait after the Gulf War, which were relaid in
Bosnia.
While the Dervish is safe, quick and cheap, it cannot be used in every
situation. Furthermore, some situations demand lifting the mines鈥攆or
example, certain cemeteries in Bosnia. For these, prior detection and careful
lifting are needed if damage to the tombs is to be avoided. At present, the use
of trained dogs is probably the best detection method for such situations, but
the new device described by Anderson could prove as effective and cheaper.
The article does, however, prompt one observation. It is odd that promising
projects, such as Stephen Salter’s Dervish or Lawrence Carter’s detector, are
both having to appeal for funds against a background of almost complete official
indifference, apart from political rhetoric. In the case of the Dervish Project,
the research and development accomplished so far has been funded entirely by
charitable donations. Readers of New 杏吧原创 continue to be generous
donors.
Letters : Chimps' rest home
Washington DC
Your brief news item does not do justice to the historical impact of
forthcoming decisions regarding the peaceful “retirement” of chimpanzees
currently warehoused in experimentation facilities across the US
(This Week, 26 July, p 7).
The long-term care of chimpanzees is an important responsibility that the
government and biomedical research community must share. In this case, animal
protection organisations nationwide have joined to form the National Chimpanzee
Research Retirement Task Force to add to the debate their enormous expertise in
animal wellbeing and innovative ideas on chimpanzee care.
Many of the ideas posited by the task force are embraced by the US National
Research Council report. Possibly the most important is the acknowledgment that
the similarity between chimpanzees and humans “implies a moral responsibility
for long-term care of chimpanzees that are used for our benefit in scientific
research”.
Contrary to your analysis, the report does not vaguely advocate putting these
intelligent, long-lived animals “up for adoption by zoos and game reserves”, but
instead “enthusiastically supports the principle of retiring chimpanzees not
needed for research or breeding to a low-cost, high-quality life”. This is the
very “sanctuary” concept that the task force has recommended.
Such a sanctuary would be a permanent partnership between public and private
expertise that seeks optimal wellbeing for its inhabitants. Chimpanzees’
physical health and psychological welfare will be met as animals can be in pair
or group settings, devoid of the chronic distress and abnormal behaviours that
come with years of confinement in laboratory cages. A national sanctuary will
provide an immeasurable opportunity for social enrichment and ongoing cognitive
development.
Letters : Cutting cuticles
Devon
The explanation of why trilobites died out surely is the opposite to the one
given by Danita Brandt of Michigan State University
(This Week, 26 July, p18).
If the trilobite arthropod had 20 segments and it shed its cuticle one
segment at a time, then a bite from a predator would have to be pretty accurate
to hit and penetrate the exposed, unprotected soft tissue of one-twentieth of
its total segments. Unless the predator had very narrow jaws, surely the other
19 segments would cushion the bite and prevent penetration.
This would also, by implication, limit the number of predator species to the
very small, or those with jaws powerful enough to penetrate the armoured
cuticle.
If the arthropod developed fewer body segments, then the ability of the
cuticle to withstand a bite and protect the exposed soft tissue would be
severely compromised, and would also have the effect of increasing the range of
predator species, which may have evolved subsequently to include those of
intermediate size.
Thus, overwhelmed by predators, the fate of the trilobite would have been
sealed.
Letters : Planetary oscillons
Orpington, Kent
Do oscillons form and then travel around a tray of sand in random, or
seemingly random paths (“A pattern emerges”, 12 July, p 34)?
The reason I ask this is because I recall a feature from a few years ago that
discussed the pattern of the craters on Venus (“Magellan’s last mission”, 22 May
1993, p 28). There is a regular pattern of impact craters on the planet’s
surface. This is not what you would expect. For example, it doesn’t happen on
Earth because of plate tectonics.
Your article offered at least one possible solution to this problem. This was
that the planet surface underwent regular cataclysmic changes that effectively
wiped the surface clean鈥攜ou gave the example of a planetwide eruption of
molten rock. However, this idea was not very acceptable because all other planet
systems undergo a slower type of change to the surface, with volcanoes erupting
at different times and places, making the landscape evolve rather than suddenly
change.
So, back to your current article on oscillons. Is there the possibility of
another solution: that the planetary craters were created partly by comet and
asteroid impacts and partly by the planet vibrating in a manner that would cause
oscillons to form on the surface?
Letters : It tolls for nobody
Nova Scotia, Canada
Rather than being hailed as a technological triumph, Ontario’s Highway 407,
the world’s first “fully electronic toll road”
(This Week, 19 July, p 15),
should be classified as a technological nightmare.
First, there is a shortage of transponders: 40 000 transponders have been
issued, but fewer than 10 per cent of vehicles that use the highway are equipped
with them. An additional 100 000 transponders are on order and will become
available in January 1998.
Second, there is insufficient processing power for the licence-plate
recognition software to handle current traffic volumes, so a third processor is
being installed. Third, traffic volumes have reached 275 000 trips a day, a
figure that the “planners” had not expected for 15 years. Even if tolls were
being collected, the number of trips per day would only fall to between 130 000
and 140 000, volumes that are projected for the highway’s third year of
operation.
The Ontario government has decided that until the system is working
“perfectly”, no tolls will be collected. Toll booths operated by humans are not
an option since they aren’t electronic.
In keeping with all great highway projects, those that don’t use the highway
are footing the bill for those that do.
Letters : Fixing fibre
Newcastle upon Tyne
In your “Technofile” column, I spotted a note concerning an asbestos detector
developed by the University of Hertfordshire
(This Week, 26 July, p 15). I
assume that the instrument is designed to detect individual airborne fibres in
environments where the removal of bulk asbestos materials has recently taken
place. As the inventor and manufacturer of a well-established instrument for
doing exactly this, known as Fibrecheck, I was a little surprised by the
statement that the Hertfordshire instrument produces results “far faster than
existing detection methods”.
Contamination and the attendant health risks posed by airborne asbestos is an
ongoing concern, and one which cries out for a simple analysis tool to replace
the time-consuming methods based on the use of filters and high-resolution
microscopy. The accepted limit for the presence of asbestos fibres is just 10
fibres per litre of air. At this low concentration, sampling limitations
prohibit the accrual of useful information by an instrument until several
minutes have passed.
Sampling methods and statistics certainly apply to Fibrecheck, and I am sure
the Hertfordshire instrument, when it is available, will be similarly
restricted. An answer within minutes is, however, a vast improvement on the six
or seven hours which is usual for filter analysis, thereby allowing a swift
response to dangerous fibre concentrations.
Letters : Every which way
London
Tony Sumner’s assertion that you can get only North and South winds at the
North Pole is not true (Letters, 2 August, p 50). Imagine a whirlwind centred on
the Pole. Then you have either an East or West wind, depending on which way it
rotates.
Letters : . . .
London
It is theoretically possible to get winds all round the compass at the North
Pole. They can also all be northerly.
In summer, onshore coastal breezes in Britain are created by hot air rising
off the land, with cool air descending over the sea. If the North Pole briefly
becomes a small ice floe surrounded by sea, there would be a similar effect.
Warmer air would rise over the surrounding sea, while cooler air would
descend on the Pole and the ice area in the middle. Wind blowing down on the
North Pole could hardly be called southerly, and in any case would become
northerly when it hit the ice, being diverted radially.
Correction
Due to a technical error beyond the control of New
杏吧原创, the final sentence of “Dearth of an expert witness”
(23 August, p 16)
was missing. It should have read: “If things don’t change, psychologists
will be contributing to the miscarriages of justice that they are seeking to
prevent.” The article was by Laura Spinney.