Letters : Timber traffic
South Turramurra, NSW, Australia
I was most interested in the article on biodegradable cars (“Cars that grow
on trees”, 1 February, p 36).
It just proves the old adage that history repeats itself. Without realising
it in the past, car manufacturers have produced various levels of biodegradable
cars, such as the GN (and others) in the 1920s, which had wooden chassis rails.
In the 1950s, the British sports car manufacturer Marcos was making cars with a
full plywood monocoque frame. Frank Costin, the noted aeronautical engineer, was
responsible for the Marcos design as well as some timber-framed cars built
later, under his own name.
Then there was the innovative aircraft manufacturer De Havilland, where
Costin got his training, which built the famous Mosquito fighter/ bomber of the
Second World War, a very biodegradable aeroplane with its almost totally wooden
construction.
Some cynics would say that a number of cars from the 1950s and later are very
biodegradable, because of the speed they return to iron oxide.
Letters : Balls for boats
Spalding, Lincolnshire
The missing mouse balls might have been discovered (Feedback, 4 January,
Letters, 18 January, p 48, and 8 February, p 51). According to the February
issue of Classic Boat, a team of Irish boat enthusiasts is partially
recreating Ernest Shackleton’s Antarctic expedition of 1914 to 1917. To this end
they have built the Tom Crean, a replica of the James Caird, Shackleton’s ship’s
lifeboat, in which he sailed 800 miles to South Georgia.
The new boat is of cold-moulded timber construction and includes seven
watertight compartments which were fitted with a ton of computer mouse balls and
gravel for ballast.
Letters : Rocks on ice
Williamstown, Massachusetts
Meteorites from Mars are not worth the recent auction price, but not only for
the reasons given by Phil Bagnall (Forum, 1 February, p 50).
We don’t have to wait for another meteorite from Mars to fall to Earth. There
are many sitting on the ice in Antarctica waiting to be picked up, the way most
meteorites are found these days.
All it would take is for the million dollars to be added to the underfunded
Antarctic research programmes, instead of spent at auction in New York.
杏吧原创s on snowmobiles could bring home more meteorites, not only for
collecting but also for science.
Letters : Fake security
by e-mail
I liked the story about the OK/Cancel keys (Feedback, 8 February). I think
that this is more common than most people realise, and that a lot of barriers
are purely imaginary. If something looks impressive and formidable, people
assume it’s not worth their time trying to break it.
Take, for example, Microsoft’s 17-digit key for its Windows 95 discs (it
takes the form xxxxx-OEM-xxxxxxx-xxxxx) [sic]. Excluding the possibility that
some digits are predetermined, there should be less chance of guessing the right
code than there is of winning the lottery jackpot two weeks running. So why is
it that I can put any of our Windows 95 CDs into a machine then pick any of
their codes at random and it in stalls.
Yet Microsoft’s desire to prevent software piracy at other times is intrusive
to the point of being ridiculous. Trying to install a new hard disc, which the
manufacturer had sent without instructions, I looked in vain for help from
Microsoft, whose operating system software it was that required configuring. A
keyword search of their online help found three entries on how to tell whether
preinstalled software on a hard disc is legitimate, but none on how to set up a
newly installed disc.
Letters : Your own voice
Norwich, Norfolk
I was surprised that in Alison Motluk’s “Cutting out stuttering” (1 February,
p 32), there was no follow-up to the statement “there is virtually no auditory
self-monitoring”. Surely that could be the key to the whole matter. Speech is
basically a muscular activity and all muscular activity relies on feedback to
determine whether the messages sent to the muscles are having the correct
effect.
Let’s say that the brain has sent the appropriate signals to the appropriate
muscles around the mouth to produce the initial sound of the word
“stutter”鈥攁 hissing sound. In a non-stutterer, a message would return,
effectively saying that the “s” sound had been heard. Having digested this
message, the brain could then commission the next sound, the “t”鈥攁nd so
on.
However, in the case of a stutterer, the feedback message that the “s” sound
has been heard is perhaps missing, so the brain repeats the command again,
and again, and again, thus producing a ssssssssstutter.
How does this fit in with the situation when a stutterer reads out aloud in
time with a non-stutterer and fails to stutter? My interpretation would be based
on the following.
If you scratch your head, you hear a loud sound. Do the same to someone else
and you hear very little. In other words ,sound transmits very well through our
heads. Does the brain of the stutterer not hear the internal sound transmission,
for whatever reason, but can substitute the sound of another person’s voice if
it is producing the right sounds at the right time?
Letters : . . .
Southampton
Motluk mentioned a functional imaging study on stuttering and the possibility
of lesioning as a therapeutic tool. She referred to the study by Fox et al
(Nature, vol 382, p 158). However, she omitted to mention an earlier study using
positron emission tomography by Wu et al (NeuroReport, vol 6, p 501) who found a
rather different pattern of activations.
There are, of course, differences between the two studies鈥攆or example,
one was based on glucose metabolism, the other on labelled water鈥攂ut it
might be premature to base therapeutic interventions on only one functional
imaging study.
Researchers should also be aware of the lesion literature relating to the
spontaneous recovery of long-standing stuttering after the occurrence of
cerebral pathology. In one study I reviewed in Neurology (vol 35, p
1341), two patients ceased to stutter after developing early signs of multiple
sclerosis. The author, A. E. Miller, thought that bilateral cerebellar
dysfunction might be the therapeutic mechanism.
I wish Fox and his colleagues luck in their attempts to alleviate stuttering
with transcranial magnetic stimulation. They should, if possible, also aim for
the cerebellum in addition to the right superior premotor area. My own view is
that what might work best of all is splitting the corpus callosum.
Letters : . . .
Barry, Glamorgan
There is an alternative to surgery which any sufferer can try.
A former colleague who stuttered badly was, understandably, rather taciturn.
All this changed when he drank. His disability was inversely proportional to his
alcoholic intake. When drunk he became extremely loquacious and fluent.
Fortunately, he was also interesting and witty.
Another point in favour of this treatment is that, even if it doesn’t work,
after a time the stutterer doesn’t give a hoot anyway.
Letters : Blooming group
New York
It is awkward and embarrassing to have to claim credit for one’s own work.
However, Roger Lewin, in his otherwise outstanding article on the revival of the
concept of the superorganism (“All for one, one for all” 14 December, p 28), has
made a misstatement of fact. Lewin outlines the high degree of activity
generated during the past year and a half by the “Group Selection Squad”. He the
identifies the leader of that squad as David Sloan Wilson. Wilson is, by dint of
over 25 years of hard work, the most visible of group’s champions. However, he
is not the Group Selection Squad’s leader.
I founded the Group Selection Squad in August of 1995 to overcome the
resistance which met the original theories about group selection and
superorganisms in my book The Lucifer Principle: a scientific expedition
into the forces of history (Atlantic Monthly Press).
Evolutionary biologists like Wilson had attempted to advance group
selectionist ideas against considerable opposition for the previous 20 years.
Worse, the fear of ostracism engendered by the dominance of individual
selectionism impeded the development of new evolutionary concepts.
To combat this obstacle, I conceived the Group Selection Squad, personally
funded it, named it, recruited its members, led it, worked diligently to make
its efforts (and those of its participants) known in the scientific press, and
literally dropped nearly all other scientific labours for over a year to
generate the self-sustaining momentum the group possesses today.
Letters : Flat flight
Preston, Lancashire
As I am a hobby pilot, Dirk Koopman’s letter on the lifting power of a wing
as a flat plate (Letters, 1 February, p 55) set me thinking. Should I be worried
if the maintenance engineers accidentally bolted flat plates instead of wings on
the flying club machine I normally use?
My normal takeoff airspeed is 55 knots (27 metres per second) and with an
angle of attack of 16 degrees (the stall point of a typical light aircraft
wing), I calculate that this gives an uplift of 133 newtons per square metre.
But the wing loading at maximum takeoff weight is 800 newtons per square metre,
suggesting that, contrary to Koopman’s letter, the flat plate component only
provides a small fraction of the lift.
Moreover, my normal takeoff airspeed incorporates a good margin beyond the
stall, so that the actual angle of attack is considerably less than 16 degrees,
reducing this component further. If I had to rely on the flat plate effect, the
likely outcome would be that I would fail to get airborne and end up bending the
nosewheel and propeller as I overshot the end of the runway. From Civil Aviation
Authority accident reports, this is apparently a favourite pastime of amateur
pilots.
I would suggest, however, that aircraft designers really do need to make use
of Bernoulli’s equation to achieve lift. The effect is quite small (800 newtons
per square metre is less than 0.01 atmospheres), but very effective. If all that
was needed to calculate lift was the swept volume and downward velocity, what
would be the purpose of wind tunnel tests and computational fluid dynamics
codes? Or have aerodynamicists been hiding the truth to protect their
interesting jobs?
Letters : . . .
Aylesbury, Buckinghamshire
Naturally, when the lift force is being discussed, the focus is on how this
force is coupled to the wing, rather than on how it is balanced by the
downwash.
Koopman is on the right track when he points out that preventing the airflow
from detaching from the wing increases lift as a corollary of increasing
downwash, but he has failed to follow through this line of thought. The downwash
is driven by air that flows over the upper wing surface. This airflow can only
exert an upwards reaction on the wing in a negative sense. The reduction in its
pressure effectively makes the wing buoyant in the air mass. This accounts for
the strength of the lift force, since the mass of the entire air column is
recruited to hold the wing aloft.
Letters : Flight and fight
Cambridge
Pat Shipman provided an excellent review of the evidence for the possible
dinosaurian origins of birds (“Birds do it . . . did dinosaurs?”, 1 February, p
26). A “tree down” model of the origin of flight in birds sees feathers partly
as a device for controlling high-speed collisions鈥攚ith the ground. But
ground-dwelling predatory dinosaurs would have had another type of thump to
contend with鈥攃olliding with their (often larger) prey after a running
chase and attacking leap.
Feathers presumably arose originally for insulation and display, but a row of
feathers along the arms and tail could have given a small, dromaeosaur-like
early dinosaur another advantage: they could help it to jump higher, stay in the
air longer, and land more safely. Feathers around the tail would assist
stability and help to ensure that it landed feet first.
With even a little bit of extra time in the air, a dinosaur might be able to
slash using both its hind legs, and choose a better position for biting its prey
or rival. Each improvement in the “wings” would enhance this advantage, until in
very small dinosaurs something like powered flight was achieved.
Letters : . . .
Abingdon, Oxfordshire
Shipman correctly cites T. H. Huxley as the first to claim a dinosaur
ancestry for archaeopteryx, in 1868. The curious feature of this is that Huxley
entered the fray so late; before 1867, he considered that birds and dinosaurs
shared a common Triassic ancestor, and dismissed archaeopteryx as being too
recent to be of significance.
Between them, the great Victorian scientists considered most of the
possibilities, such as warm-bloodedness, being debated today. Some read so much
into the archaeopteryx specimen that Hugh Falconer, the palaeontologist, was
moved to write in 1865: “Tomorrow you will find the liver and lights; and, in
the long run, the fossil song.”
Letters : Cracking down
London
You state that RSA Data Security’s 40-bit code is the most powerful that can
be exported from the US (This Week, 8 February, p 5). Actually, 56-bit RSA can
be exported, but only by companies that agree to key escrow. And, of course,
this is the real agenda.
RSA and the US government want the market to demand stronger keys, so that
American software companies will be forced to agree to key escrow in order to
compete in the world marketplace. Many of the larger American software companies
are currently refusing to play ball at all: Netscape and Microsoft spring to
mind.
Everyone knew before Ian Golberg did it that 40-bit RSA would be cracked
rapidly. But that doesn’t make much of a news story, especially since the code
had been cracked before. Of course, doing it again shouldn’t be much of a news
story, either, but the US government moves in mysterious ways.
Goldberg is being naive when he says “there is no good reason for these
controls”. Of course there is a good reason鈥攖he US government can crack
56-bit RSA with ease. They are hoping that the rest of the world will “catch up”
and outlaw strong encryption. The rest of the world’s governments will surely
see the wisdom of this, even if their citizens don’t.
An example of this process is a meeting to be held in Dublin soon, hosted by
the US Justice Department, where 22 countries, Britain included, will sign an
accord to ban the sale of encrypting telephones.
Letters : Insect worship
Sydney
Judith Hanna of London is a little confused about cane toads and beetles
(Letters, 8 February, p 50). Moths of various kinds were introduced into
Australia, particularly the most famous, Cactoblastis. This has been
given star status as a triumph of biological control, having cleared about 25
000 hectares of land that had been invaded by the prickly pear cactus.
Within a few years the cactus was reduced to pulp, and the ecstatic farming
community of Boonarga built a Cactoblastis Memorial Hall to show their gratitude
to the insects.
The situation with cane beetles, a pest of sugar cane, and cane toads was
completely different. The cane toad was brought into Australia by cane growers,
despite warnings from scientists. No research had been carried out on the cane
beetle.
The cane toad failed to do the job, even though it had proved useful in other
parts of the world on different species of insect pests.
Today, governments are well aware of the dangers of unwise species
introductions. Rigorous research is always carried out before a new animal or
plant is brought into this country. We have learnt wisdom after the disastrous
early years of white settlement, when the newcomers tried to recreate Europe in
this new country.