Letters : . . .
Christchurch, New Zealand
You seem to have printed an article destined for the 1 April edition eight
weeks late. Or perhaps the writer had overdosed on Miami Vice or Nancy
Reagan’s memoirs.
Letters : Prize pair
Ontario, Canada
While the review (11 May, p 42) by David Bradley of Making PCR
concisely indicated what to expect from reading about this fascinating
biological discovery, both your journal and several others have failed to
indicate that the very visible Kary Mullis shared the Nobel prize with Michael
Smith of the University of British Columbia鈥攚ho, incidentally, donated
half of his part of the prize for the establishment of scholarships and awards
to promising young scientists.
Letters : Neolithic retsina
Emsworth, Hampshire
While browsing through John Gerard’s The Herbal or General History of
Plants (originally published in 1633) I came across a reference on the
turpentine tree which may shed some light on why Stone Age people may have drunk
wine tainted with this substance (This Week, 8 June, p 5). It seems that a
concoction made from the turpentine “beans” blended with egg yolk and white wine
was a sure cure for gonorrhoea: “It helpeth most speedily the Gonorrhoea鈥�
commonly at the first time, but the medicine never faileth at the second time of
taking it.”
However, as well as being a remedy for this disease, the fruit of the tree
may also be responsible for people catching it, as the same treatise claims it
“stirreth up fleshly lust”.
Letters : . . .
London
If Patrick McGovern and Hazel Muir had joined the Greeks or myself in a glass
of retsina, they would realise the timelessness of 7000 years of viniculture and
how wrong they were to assume that white wine smelling and tasting of turpentine
produced by pine resin additives cannot be enjoyed without a hangover.
Letters : Borage is best
Maldon, Essex
As a result of work in gene transfer from borage plants to tobacco, we learn
that commercially viable levels of gamma-linolenic acid (GLA) in seed oil crops
are probably one to two years away (Technology, 8 June p 21).
But there is no need to wait if you want to increase your intake of GLA.
Borage has successfully been cultivated as a source of GLA in Britain and
elsewhere for at least eight years. You can buy the encapsulated oil from a
number of reputable chemists and health food shops.
Letters : Heart of the matter
Halifax, West Yorkshire
I am appalled by the idea that Chlamydia pneumoniae is implicated in
coronary heart disease but is not well into large scale human studies seven
years after the idea was first put forward (“Can you
catch a heart attack?”, 8 June, p 38).
It is surely irresponsible to delay research. The cost of this would surely
be a fraction of the present cost of mortality, morbidity and treatment.
If studies are not started soon, they may well become impossible. Most GPs
faced with a patient with heart disease and, say bronchitis, would be completely
justified in prescribing a broad-spectrum antibiotic鈥攚hich just happens to
treat C. pneumoniae, as well as the bronchitis. If this scenario is
commonplace, we will never be able to find enough people with the untreated
bacterium to test for the link with heart disease.
Letters : Super gas
Bromsgrove, Worcestershire
I’ve got another reference to the meaning of the name CS
(Letters, 25 May, p 59).
Seymour M. Hersh, in Chemical and Biological Warfare (Panther 1970),
describes CN, CS and DM, the three US military riot control agents then
available. CN is (-chloroacetophenone (C6H5COCH2Cl),
and is the mildest of the three. CS, which is ortho
-chlorobenzalmalonitrile (ClC6H4CHC(CN)2), was
developed to be faster-acting and more toxic than CN. DM, the nastiest (“not
approved for use in operations where deaths are not acceptable”) is the German
First World War agent adamsite, or diphenylaminochloroarsine (NH(C6
H4)2AsCl).
According to Hersh the “S” in CS stands for “super”. That’s all he says.
Perhaps CN and DM were simply letters taken from their chemical names, then CN
was thought of as “Control Normal” so the upgrade became “Control Super”.
I read once that the installers of the Electronic Random Number Indicator
Equipment-at Lytham St Annes disrespectfully and unofficially named it after
their foreman, Ernie.
We thought it was named after Ernie Marples, the Postmaster
骋别苍别谤补濒鈥抬诲
Letters : Snap and shrink
Dorking, Surrey
I regard your article on the manufacture of satellites as an advertising puff
for the American company promoting its carbon composite structures
(“Snap-together satellites”, 23 March, p 34).
The article failed to mention some of the problems with carbon composites,
which include shrinkage and possible distortion in long-term exposure to vacuum
and its poor electrical conductivity compared with aluminium. Designers also
have less confidence in composite materials, and so apply greater safety factors
for mechanical loading, particularly for fittings involving adhesive
bonding.
The conductivity is perhaps the greatest problem since a conventional
spacecraft structure is used as both a ground plane and a Faraday cage to reduce
interference from radio antennae. Carbon composites are nearly transparent to
radio frequencies.
The quick delivery of the “snap-together” structure is interesting, but
structures are rarely the items that determine the speed of a spacecraft’s
construction. All this has been well known on this side of the Atlantic for 15
years or more and carbon composites are used extensively in European spacecraft
wherever suitable.
Letters : Timber trade
Whiteside, South Africa
The article concerning the scheme designed to encourage British stores to
sell only ecologically sound timber reported claims that the scheme is a
restrictive trade practice and is therefore illegal (This Week, 18 May, p
7).
It would appear that in 1988 a European precedent was established. The
European Community charged Denmark with protectionism when it banned beer and
soft drinks that were not in refillable containers, but lost in the European
Court in 1988. In that case, the court ruled that the need to protect the
environment took precedence over the free trade issue.
Letters : Words on worms
St Albans, Hertfordshire
Although the long-lived mutant nematode strains created by Bernard Lakowski
and Siegfried Hekimi smash the record for artificial life span (New
杏吧原创, Science, 25 May, p 16), they are undoubtedly not the Methuselahs
of the worm world.
Recent research increasingly suggests Caenorhabditis elegans and its
closest relatives are highly specialised ecological r
-strategists鈥攖hat is, they have evolved highly compact reproductive and
developmental cycles, allowing them to multiply very fast in conditions when
food is very abundant. In contrast, most other nematodes鈥攊ncluding some
groups that may be ancestral to Caenorhabditis and
relatives鈥攔eproduce and develop more slowly, having generation times in
the order of weeks or months rather than days.
Life span has never been accurately determined for such species, but is
presumably proportional to generation time. Some nematodes have only one
generation per year, and obviously live much longer than the new mutants.
Letters : Safe journeys
Welwyn Garden City, Hertfordshire
I refer to the article on malaria and its prevention with mefloquine (Lariam)
(“Malaria pill stands accused”, 27 April, p 14). It is disturbing that this
article should appear in your journal. The temptation is to present a lengthy
statement correcting its inaccuracies. That, however, would miss the essential
purpose, which is to provide travellers with the best advice. The facts they
need to know are:
Malaria is a killer disease and protection must be taken appropriately.
Extensive independent clinical studies of Lariam published in scientific
journals show an incidence of serious neuropsychiatric side effects at 1 in 10
000. Other less serious side effects can be expected in about 22 per cent of
travellers as stated on our data sheet.
Travellers who need advice will find answers to questions in the Lariam
patient information leaflet contained in the product pack.
General practitioners, travel nurses and pharmacists can provide further
advice and have access to Roche Products’ medical information services.
We take very seriously reports of side effects on any of our products and
sympathise with any person who encounters them. It is not helpful, though, for
anecdotal, unscientific reports to be regarded as fact. Indeed, where Lariam is
concerned, our principal concern is that recent misleading media reporting may
result in an increase in deaths from malaria. That would be a needless
tragedy.
Letters : . . .
Le Cannet, France
Gullen alleges that plants such as poppy, coca, and tobacco have evolved a
parasitic relationship with humans via the production of addiction-producing
drugs. By stretching one’s imagination slightly further, it is easy to see that
sugar cane and roses have achieved a similar feat: addiction to refined sugar,
and the visual and olfactory delights of roses having spread these vegetable
parasites to every corner of the globe. And what about those endless hectares of
grapevines? Extending the concept into the mineral realm, we might accuse iron
ore deposits of their parasitism in having addicted us to the endless and
insatiable building of automobiles.
Humans have had a quite beneficial relationship with drug-producing plants
for 40 000 years or more: one might even invoke the concept of symbiosis. But
since the institution of drug laws and drug wars, symbiosis apparently has
become parasitism. Either these two concepts are ambiguous, or Gullen has fallen
prey to the 20th-century’s most serious addiction, drug prohibition mania.
Letters : Dirty noise
Munich, Germany
You state that “background noise鈥an actually make it easier to pick
up faint signals”, and add “This extraordinary idea emerged in 1981.” (“Noises
on”, 1 June, p 28).
Well, in the field of control circuitry engineering, this knowledge was put
to good use much earlier, when technicians introduced “dither” signals into
control loops to lower their response thresholds. In other words, they increased
the overall system sensitivity by adding an artificial background noise to an
otherwise clean signal.
Letters : Methane effect
Baulkham Hills, New South Wales
I was interested to read Fred Pearce’s contributions on greenhouse gases in
which he refers particularly to the important role played by methane (“Trouble
bubbles for hydropower”, 4 May, p 29, and This Week, 25 May, p 7).
I think that its importance has been overestimated. The radiative forcing
effect of methane relative to carbon dioxide鈥攊n other words, its global
warming potential (GWP)鈥攈as been estimated by the Intergovernmental Panel
on Climate Change to be 25 times as great. This value is obtained by integrating
the direct and indirect radiative forcing effects of methane over 100 years.
However, this calculation assumes that all methane has the same effect
regardless of its source. This assumption is not correct. Fossil-fuel-related
methane returns carbon to the atmosphere on a geological timescale, so
it can be considered to add new carbon to the carbon cycle. By contrast, methane
emitted from the biosphere鈥攆rom rice paddies, wetlands, waste dumps,
biomass burning and enteric fermentation in herbivores鈥攔epresents a
redistribution of carbon already in the cycle.
Only the direct radiative forcing effect of biospheric methane should be
included with the direct and indirect effects of fossil fuel-related methane in
calculating its GWP. As the biosphere contributes some 70 to 80 per cent of the
methane now entering the atmosphere, the IPCC’s value of 25 for the GWP of
methane significantly overestimates its contribution to the enhanced greenhouse
effect.
Letters : Overdose
New Zealand
The political and religious factions who favour the continued prohibition of
consensual adult drug use are likely to seize upon the article by David Gullen
(Forum, 25 May, p 53), as it is one of the very few in support of their policies
to appear in a (usually) respectable scientific publication. And perhaps Gullen
himself is a radical prohibitionist. Consider his claim: “Once addicted to plant
chemicals, our greatest abilities鈥攊ntelligence, consciousness and the
ability to introspect and solve problems 鈥攂ecome useless.” This is a myth.
Gullen seems blissfully unaware that the substantial majority of people who are
addicted to drugs are gainfully employed and able to function in society quite
well. This has always been the case.
Far worse, Gullen concludes by recommending that we deal with coca plants,
cannabis, poppies and other sources of (currently) illegal drugs “with the same
ruthlessness as we deal with malaria and other organisms dangerous to human
life”. Can he be serious? Such a scorched earth policy goes far beyond anything
propounded by even the most fire-breathing antidrug warrior.
Letters : Look for the leap
Auckland, New Zealand
You have referred to the year 2000 problem, in which some people assert that
computers will stop working when 31 December 1999 rolls into 1 January 2000
(Letters, 25 May, p 58, and
20 April, p 58, and Feedback, 6 April).
Another aspect of the problem few people have mentioned is that the year 2000
is a leap year. It is the first leap year that occurs on a century (year ending
with 00) since the Gregorian calendar was adopted.
If you ask most computer programmers about the leap year rules as they apply
to computers, they will mumble something about “the four-digit year being evenly
divisible by 4 means a leap year” and they may add that “years ending in 00 are
not leap years”. But many forget that there is a further rule: years evenly
divisible by 400 are leap years.
I know that Knuth has an algorithm for leap years, but a lot of the
self-taught programmers I have met do not look such things up鈥攖hey rely on
general knowledge or they ask someone else who claims to know the rules. Since
they do not know the correct rules they cannot test their systems
completely.
This means that there will be a lot of software out there that will think
that 29 February 2000 is not a valid date and will reject it. The problems this
causes could be minor, such as traffic lights out of order, or the clock on your
PC, VCR or TV being wrong, making you miss an episode of Coronation
Street. But there could also be more serious consequences: for example,
aircraft may have trouble with their guidance systems, resulting in flight
delays or even, conceivably, fatal accidents. Things could go from bad to worse
very quickly and few will wake up to the problem until it is too late.
I suspect that a lot of the leap year problems will occur in software written
during the 1960s, 1970s and 1980s. The people who wrote it probably never even
considered that it might still be running now. Much of it will have been retired
before the millennium comes along, but there will doubtless be a number of
systems still in use by 29 February 2000 that may not recognise the year as a
leap year.
If this fault exists in only one program in a thousand, it could still cause
chaos because so many computer systems either create or use data which are, in
turn, fed to or received from other computers. Computer interdependency means
that all computer systems are only as good as the weakest program, and could
lead to many failures stemming from a single program that relies on incorrect
leap year rules.
It would be ironic if we have to switch off our high-tech computer systems
because something which has been predicted for hundreds of years finally
happens, exactly when it has been predicted to happen, but we find ourselves
unable to handle it because we have not not prepared in time.