Deep thrust
Scott Taylor’s use of deep ocean pressure to replace hundreds of tonnes of
start-up thrust to launch a rocket is environmentally and economically
attractive. I hope you continue to report his progress.
A man of numbers
The distinguished, itinerant and recently deceased mathematician Paul
Erd枚s developed the Erd枚s number, which measured the “distance”
between him and others, in much the same way Mark Newman’s algorithm does
(25 November, p 10).
Erd枚s had a profound effect on contemporary mathematics,
especially number theory and various unsolved problems.
If you co-authored a paper with Erd枚s then you had an Erd枚s number
of 1. If you wrote a paper with someone who had written a paper with Erd枚s
then your number was 2.
Erd枚s had a very large ego and made the (unproved) conjecture that every
living mathematician had a finite Erd枚s number.
Wibble wobble
I read with interest the article about the 拢5 million of damping
required on the Millennium Bridge in London.
May I suggest it might be far cheaper to set up a Ministry of Funny Walks to
encourage pedestrians to walk out of step. I’m sure John Cleese would be more
than happy to act as a consultant to the project.
Floppy friends
We all have enormous sympathy for Charlotte Morley who lost her project work
(25 November, p 59).
When typing on a computer it is very easy to delete a
paragraph before you have saved your work, and even that is enough to bring on
an attack of computer rage.
When I first started word processing about 15 years ago, the computer had no
hard drive, and consequently everything was written directly to a floppy disc.
Old habits die hard, and in all that time I have never lost a major document. I
still have access to every word I have written since then.
Those who teach computing should make it clear that a hard drive is
untrustworthy. Write directly onto a floppy, or at least transfer the file when
a session closes. Subdivide your text into sections kept as separate files, and
preferably on separate discs. If you are really neurotic, keep a set of copies
elsewhere, then fire or flood will not destroy your magnum opus.
Graphics files are often too big for a floppy, but most computers now have a
CD-writer, which is not just for pirating your music鈥擟Ds will carry dozens
of big graphics files.
This might all seem very trite, but prevention rather than cure is simple,
cheap and, apparently, the biggest blind spot of most computing instructors.
Responsible mining
Your article “Tails of Woe”
(11 November, p 46) concerning environmental
disasters caused by dumping mine tailings is very topical given the recent
collapse of a dam wall at a gold mine in Romania.
However, a simple final flotation step could remove the remaining sulphides
(mainly pyrite) prior to tailings being discharged. This step produces a benign
silicate waste, which does not cause pollution because it contains insufficient
sulphide to generate acid. The pyrite concentrate can be further treated or
returned to the mine as backfill. Wastes containing cyanide can easily be
treated to make the toxic chemicals harmless prior to discharge.
I could not let your article pass without attempting to present the
enlightened and responsible position of the mining and metallurgical industry
today.
Viral vigilance
Your article suggesting that text e-mails may contain viruses is misleading
(9 December, p 14).
The bulk of the article makes it clear that the messages you
say could be infected with viruses are “HTML-encoded” messages, rather than
plain text e-mails.
Any system, such as HTML, that allows the sender of a message to remotely
execute programs, such as Word macros, Java applets, or Visual Basic Script, is
vulnerable to abuse. Mail tools that start these programs put our machines at
risk. HTML-encoded messages are littered with tags, but if the mail tools do not
try to execute the tags, the computer will not be put at risk.
On balance
Generalisations are risky, so before stereotyping cyclists as innocent victims
(2 December, p 52)
Kevin Tilbrook should spend a day in the English city
where I work (Cambridge) and answer the following questions: How often do you
see a motorist cross a traffic light thirty seconds after it’s gone red? How
often do you see a cyclist do it?
How many cars do you spot going the wrong way down a one-way street? And how
many bicycles? How often do you see a motorist driving on the pavement? And
cyclists? Most important of all, how many cars do you see without lights after
dark? Now, what about bicycles? And which are harder to see?
Many car drivers are thoughtless idiots. Regrettably, so are many cyclists,
and we all pay to put them back together again. Please, let’s keep some balance
in the debate.
It was this big . . .
Why stop at old cars and submarines to make artificial reefs
(25 November, p 59)?
A really large structure鈥攁 disused Shell oil rig, say, would really
keep the trawlers away.
Finding the energy
It is depressing that discussion of alternative sources of energy so often
refers to “renewable energy”
(2 December, p 3).
The concept is contrary to the established laws of science. It is the exact
equivalent of perpetual motion which beguiled some people a century ago.
That the term should have such wide currency is a sorry reflection on the
decline in scientific literacy over the past century. A better term for wind,
water and solar energy would be “ambient energy”, reflecting the low intensity
of such sources, their essentially unreliable nature, and their unsuitability
for anything other than trivial local use.
Complex societies are synonymous with intrinsically high energy consumption.
The only concentrated primary sources of energy (excluding local and limited
hydroelectric power) are nuclear or carbon-based. A society that demands
exponential economic growth and simultaneously vetoes both increased burning of
carbon and development of nuclear energy is not only intellectually deranged but
is truly possessed of a death wish.
Agony and ecstasy
I was amazed at the suggestion that salt should be added to bottled water in
order to prevent “water intoxication” and two deaths per year as a result of using ecstasy
(25 November, p 11). It has been estimated that in Britain today,
mean salt intakes are more than twice the recommended level. Simply not adding
salt during cooking, even though not enough to bring intakes down to the
preferred level of about 5 grams a day, would still lower the incidence of
strokes and heart disease by 26 per cent and 15 per cent respectively.
I agree that ecstasy users should be protected from “water intoxication”, but
not at the expense of others in the community. If the drug were produced and
sold under controlled (legal) conditions, it would be possible to add salt
during manufacture. Moreover I think that the rest of us should be protected
from stroke and heart disease through control of the salt content in
ready-cooked meals, bread and breakfast cereals, which are the main products
damaging our health.
Wearing out hair
I am pleased that the “aquatic ape” theory
(25 November, p 28) is being given
another airing, considering the weight of evidence in its favour. However, the
pattern of our baldness suggests that another factor was involved in the
disappearance of the hair.
Like chimpanzees, we have little hair on our hands or feet or face. Tufts of
hair in the armpits and groin are useful for scent signalling. Elsewhere, we
have most hair on our heads, next most on arms and legs, followed by the upper
trunk, and least on the lower trunk. In other words, we have least hair where we
are most likely to wear clothes.
Clothes-wearing people have little use for hair, and it only makes life
easier for parasites anyway. So, let’s look for our ancestors along the ancient
seashores, and also in temperate climates where they might have worn
clothes.
Roots of HIV
In his book, The River, Edward Hooper proposes that an oral polio
vaccine tested in the former Belgian Congo in the late 1950s by the Wistar
Institute of Philadelphia was manufactured in the cells of chimpanzees infected
with the precursor of HIV-1, the cause of the AIDS epidemic
(16 September, p 4).
He also describes a correlation between putative early AIDS cases and sites of
vaccination.
At a meeting held in September at the Royal Society, published and
unpublished documents, plus the testimony of numerous scientists with first-hand
involvement in the manufacture of the vaccine, agreed that it was produced in
macaque and not chimpanzee cells. This was confirmed by sensitive tests on
remaining vaccine samples, which also proved negative for AIDS-related viruses.
In addition, accurate epidemiological information contradicted any relationship
between vaccination and AIDS. Moreover, data on molecular analysis of HIV
evolution, virus distribution in chimpanzees and survival of HIV under the
conditions of vaccine manufacture presented by various laboratories at the
meeting were inconsistent with the polio-virus hypothesis.
Against this avalanche of facts, Hooper musters hearsay, speculation and a
heavy dose of effrontery. In his latest letter (14 October, p 54) he admits
having no witnesses for the central idea that the polio vaccine was produced in
chimpanzee cells. According to the same letter, Hooper still believes that he is
in a horse race, but he has failed to notice that the horse he is flogging is
dead.