Letters: Genes and madness
A major flaw in the neurological and brain-imaging research which your
article describes, and perhaps the reason for the absence of a single and
coherent ‘scientific’ explanation for ‘schizophrenia’ to date, is the question
of whether it is legitimate to search for an aetiological explanation common
to all cases diagnosed as schizophrenic. Richard Bentall, professor of clinical
psychology at Liverpool University, for example, has argued that the diagnostic
criteria for ‘schizophrenia’ are highly over-inclusive and that any two
‘schizophrenics’ might be suffering from a completely different cluster
of symptoms. He rightly suggests that research should concentrate on classifying
research subjects according to the presence of discrete symptom types such
as ‘hallucinations’ or ‘delusions’ in order to gain an understanding of
the mechanisms maintaining each separate phenomenon, thus avoiding categorical
errors and confusion.
Other research avenues contributing to our understanding of schizophrenic
symptoms include cognitive experimental psychology. Work on reasoning processes
in subjects suffering from delusions, for example, is beginning to tease
out the similarities and differences between ‘normal’ and ‘delusional’ reasoning.
Schizophrenia research and treatment could benefit much from an integrated
approach, leading to the development of a broader spectrum of anti-schizophrenic
drug treatments, and to the continued development of a cognitive therapy
approach. This form of therapy empowers patients through helping them gain
an understanding of their bizarre and frightening experiences, addressing
their emotional distress and employing psychological techniques to enable
them to control, for example, the frequency and intensity of hallucinatory
experiences, or to reduce the degree of conviction in a delusional belief
and to improve appropriate drug compliance.
Ronald Siddle and Douglas Turkington Newcastle Cognitive Therapy Centre
Carolyn John Durham University
Letters: Warming or cooling?
Did you not carry an article to the effect that global warming is not
happening – in fact, that there is a slight cooling trend (‘Not warming,
but cooling’, 9 July)? My reaction was that for once the US decision to
wait for more information was justified.
In ‘All gas and guesswork’ (30 July), your ‘best estimate’ in the table
on how global temperature is likely to rise is 3.5 degree C by 2100.
Should not this article at least have mentioned the alternative findings
you so recently published, instead of accepting global warming as a fact,
albeit hard to quantify?
John Sankey London
* * *
Fred Pearce writes: There is no ‘global cooling’, but there is growing
evidence that local cooling caused by aerosols (for instance sulphates from
power stations) is cancelling out global warming over some industrialised
areas – most noticeably central Europe. This won’t stop ice melting over
Antarctica and Greenland, causing the sea level to rise. Nor will it stop
global warming elsewhere around the world.
It certainly does not alter the fact that humanity is drastically interfering
with the atmospheric chemistry that helps determine climate. For a crude
analogy, if you pull one side of a rubber band to the left, hold tight and
then pull the other side to the right, the effect isn’t cancelled out –
you are more likely to snap the band.
Letters: Central by-products
Tim Brown of the National Society for Clean Air and Environmental Protection
expressed the view that biodiesel production does not make sense in energy
terms because the ‘energy output’ from its use is of the same order of magnitude
as the energy input for production (Letters, 23 July). He also stated that
proponents of biodiesel ‘justify’ production of the fuel by factoring in
the by-products of the process, rapemeal and glycerol.
Firstly, I would like to make the point that inclusion of by-products
in an energy and economic assessment of biodiesel is not an artificial means
of ‘justifying’ production. Rather, an assessment which did not account
for the by-products would be unrealistic as both rapeseed and glycerol have
a realisable value which is exploited by existing biodiesel manufacturers.
Studies have shown that even where no by-products are considered, there
is a net energy gain resulting from biodiesel production under all but the
most catastrophic conditions. Inclusion of the by-products meal and glycerol
in the calculation gives an energy output to input ratio of around 3 to
1. This figure compares reasonably well with the ratio for fossil diesel
(which has been reported as 5 to 1, excluding energy used in oil exploration)
and there is potential to improve this ratio through modification of agricultural
practice and utilisation of rape straw.
Sheila Batchelor Scottish Agricultural College Aberdeen, Scotland
Letters: Seeds of doubt
The article ‘Battle for the world’s seed banks’ (This Week, 2 July)
contains numerous inaccuracies. It suggests the World Bank’s efforts to
lead the Consultative Group on International Agricultural Research out of
its present financial crisis might be conditional on ‘gaining the control
it wants’ over the CGIAR’s germplasm collections.
The Bank is one among 42 members of the CGIAR. Throughout its 23 years
of co-sponsorship of the CGIAR, the bank’s policy, based on good experience
with the CGIAR’s performance, was that international agricultural research
should remain an independent venture ‘at arm’s length from the bank’.
The article says the international agricultural research centres signed
an agreement with the UN Food and Agricultural Organization. An agreement
to put the CGIAR collections under the auspices of the FAO Commission on
Plant Genetic Resources had been drafted, agreed upon, but not yet signed.
The article continues ‘this plan . . . was rejected at the meeting in
Delhi . . .’. The CGIAR meeting (in Delhi) endorsed the draft with two
provisos: first to seek clarification whether the agreement needs to be
modified to recognise that the entire CGIAR collections are being brought
into the FAO network of germplasm collections, not just 11 centre genebanks;
secondly, to obtain assurance from the International Committee of the Convention
on Biological Diversity (ICCBD) that the agreement is in harmony with the
intentions of the convention. This assurance has been obtained in Nairobi;
the former proviso is being clarified, and the CGIAR expects to be able
to sign the agreement within the next few months.
The article accuses the chairman of proposing to establish centralised
committees, headed by the World Bank, to control funding, research and intellectual
property rights.
Committees for Oversight chaired by Switzerland and for Finance chaired
by the World Bank had already been established in 1993. The Delhi meeting
created a Steering Committee with the combined membership and terms of reference
of the existing committees, while retaining the latter.
On intellectual property rights the Delhi meeting established a committee
on genetic resources chaired by the International Plant Genetic Resources
Institute.
The article says: ‘In Nairobi . . . Serageldin . . . said he was talking
to officials at the GATT world trade organisation . . .’ Mr Serageldin did
not attend the Nairobi meeting; his written statement to the ICCBD (in Nairobi)
mentions neither GATT nor the World Trade Organisation.
Alexander von der Osten Consultative Group on International Agricultural
Research, Washington DC
Letters: Scottish water
In his review of Coming Clean: The Politics of Water and the Environment
(30 July), Fred Pearce criticises the privatised British water industry
and its failure to live up to the ideals of proper water resource management.
The English water industry maybe, but in Scotland circumstances are quite
different. Here, water and sewerage services are provided by local government,
including Strathclyde Regional Council, and water quality monitoring is
carried out by the River Purification Boards, not the National Rivers Authority.
River water quality in Strathclyde is good (over 90 per cent is class
one) and charges to domestic users lower than in England. There are, coincidentally,
no shareholders to consider. Is this too good to be true? The government
proposes to change the arrangements. As part of the proposed reorganisation
of local government in Scotland, it intends to remove control of water and
sewerage to new, specially created water authorities (quangos) accountable
to the Secretary of State.
The government emphatically insists this is not privatisation, but the
great majority of Scottish opinion including this council, rejects the proposals,
believing the current arrangements in Scotland to be preferable.
Adrian Shaw Strathclyde Regional Council Glasgow
Letters: Wrong country
The map presented with the story ‘Europe’s top 100 polluters’ (This
Week, 30 July) appears to locate the two Russian smelters at Nikel and Montsegorsk
in Finmark, Norway. For the sake of good order, I want to point out that
Norway is not a member of the sulphur league and has no sources in the
top 100 list.
The total Norwegian emissions of sulphur dioxide were some 37 kilotonnes
in 1993 – that is, far lower than the emission list required from a single
source (150 kilotonnes) to enter the top 100 list.
Jan Thompson Ministry of Environement Norway
Letters: Generations
In the last paragraph of the article ‘Ancient bacteria are frozen in
time’ (New 杏吧原创, Science, 16 July), it is stated that a time span of
100 000 years represents 1500 human generations.
Presumably, 1500 is a misprint for 3500, which would correspond to the
generally accepted interval of about 30 years between successive generations.
R. R. Hamilton Surrey
Letters: Special spots
During all the excitement of the comet crash on Jupiter, it has sometimes
been hard to know what was real and what was not. But one should correct
the impression given in your report (This Week, 30 July) that historical
visual drawings of Jupiter may show previous comet impacts. Jupiter always
has spots on it, sometimes quite prominent and often in rows; these are
its normal vigorous weather systems. The present impact scars are so big
and dark, and appeared so suddenly, that they are clearly unique in the
history of observation. Anyone with a 3-inch telescope should take a look
at this amazing sight while it lasts.
John Rogers British Astronomical Association Linton, Cambridgeshire
Letters: No failure
It was certainly never intended that only grades A to C of the GCSE
would be considered as pass grades (Letters, 30 July). The misnomer came
about because of the attempt to relate the grades of the new GCSE to those
awarded in the old GCE and CSE exams. Grades A to C were those required
to meet the university matriculation requirements while the entire range
was intended to reward levels of achievement that were worthy of recognition.
In simple terms anything other than U represents some benefit to the
pupil who took the course. The only measure of failure is a purely relative
one. For some, attaining a grade E will represent an exceptional achievement;
for others, it would be the depth of failure. The concept is that we should
measure levels of achievement.
I cannot say whether the designers of GCSE have succeeded in their objective
but if the public perception of grades D to G is one of varying degrees
of failure then their intent has not been communicated. That is, they
have failed.
Francis Glassborow Oxford
Letters: English is best
From time to time, you publish letters from the advocates of various
constructed languages, most recently Glosa and Esperanto (Letters, 7 May
and 11 June). It is difficult to see what the supporters of such curiosities
can hope to achieve.
There is a language, which, for want of a suitable name, we call English.
(Neo-English is a more accurate term, since English, that is, the language
of the Anglo-Saxons, is only one element in its composition.) This language
draws on Norse, French, Latin, Greek, original English and many others.
It incorporates all the major tongues of the EU (original English having
been akin to German and Dutch).
Neo-English is spoken by 400 million people worldwide and is the chief
language of business, science and diplomacy. It may have some oddities
such as spelling, but they could be reformed away. If anyone is looking
for an international world language, surely, Neo-English, which exists and
is used daily by 400 million people, is the best bet. (New 杏吧原创 must
believe so, because it is written in Neo-English.) For diplomatic reasons,
its chances might be improved if it were known, colloquially, by a more
appropriate name than ‘English’.
Robert Craig Weston-Super-Mare, Avon
Letters: Futile flies
Once again summer is with us and so are flies and partially opened windows.
In this period we are, yet again, faced with the age-old conundrum of why
flies persist in banging their heads against the closed portion of the window
instead of flying out of the open part.
It has occurred to us that this may not be due to simple stupidity on
behalf of the fly, but may have a good physiological reason. Flies are probably
sensitive to polarised light and it is possible that the flies are selectively
flying towards the more polarised light that comes through the glass. Maybe
other readers can comment upon the validity of this theory.
Douglas Adams once wrote upon this very subject in his legendary guide.
He described the alien creation of a ‘superfly’ that was capable of flying
out of the open window. Perhaps modern genetics on Earth could engineer
a fly that lacked polarised light sensitivity and did the same.
Simon Archer and Joe Hirano Oristiano, Italy
Letters: Very big cars
Re ‘Bigger cars for clearer roads’ by Tony Holkham (Forum, 30 July).
Step one, a stretch limousine.
Step two, make the limousine even bigger, then give it an upper floor
with room for fifty people in all.
Step three, call it a bus.
D. Burnett Sherborne, Dorset
Letters: Genes and madness
I was interested to read your article on the causes of schizophrenia,
especially ideas concerning its evolution (‘Understanding the inner voices’,
9 July). I believe this problem, and that of other major mental illnesses,
can be solved by Maynard Smith’s discussion of genetic diversity in The
Theory of Evolution, although in that book the author confined his comments
to populations of captive fruitflies.
Genes are carried on chromosomes which are made of DNA. Most animals
receive one set of chromosomes from their father and one set from their
mother. Thus they have two copies of each gene. Sometimes the two versions
of any one gene in an individual may be the same (this is called homozygous)
or sometimes they may be different (heterozygous). Often, when an animal
gets a different version of a gene from each parent, it does better in an
evolutionary sense. This is called heterosis or heterozygote advantage.
What is sometimes overlooked is that frequently many genes, each located
at a different spot on a chromosome, contribute to any one characteristic
of an individual. This is polygenic inheritance. Thus it is possible that
an individual is homozygous at most or even all of the genes that contribute
to a characteristic. However, the greater the number of versions of each
gene there are in the population the less likely it is this will occur,
since it is unlikely that both parents would carry the same versions. It
is easy to see that the odds decrease even further as the number of genes
that contribute to a characteristic, such as schizophrenia, goes up.
The possibility that schizophrenia may be more common in people who
are homozygous in some or all of these genes would account for the consistency
and rather high frequency of schizophrenia around the world (high, given
that schizophrenics have less children). Secondly, varying patterns of homozygosity
could result in varying degrees of severity, and kinds, of mental illness.
It would also explain why searches for a single schizophrenic gene remain
unsuccessful.
It is particularly interesting to speculate at what levels the heterozygotic
advantage operates; one can imagine molecular, physiological or psychological/behavioural
reasons, which could act separately or in combination. Concerning behaviour,
for example, it is conceivable that an attenuated level of obsession (although
almost any hallmark of the major mental illnesses can be substituted at
this point) is of advantage to, say, uninspired disinterest, and so on.
Jim Mackintosh New South Wales, Australia
Letters: Danger bends
Re ‘Moving target guides drivers round the bend’ (New 杏吧原创, Science,
30 July).
It has long been known, as David Lee confirms, that drivers fix their
eyes on the tangent point of a bend – but not on a two-way road curving
to the right, as shown in the diagram. You can readily check by driving
round a right-hand bend in the left lane. If the tangent point you look
at is on the inside edge you feel uncomfortable and unsafe, but not if
it is on the centre line of the road. On a left-hand bend, however, the
preferred tangent point is on the inside edge. I suspect, therefore, that
Lee’s right-hand bend was on a one-way road without centre lines.
The driving strategy identified by Lee, of constantly adjusting steering
‘to trace out a curve of roughly constant radius’ is interesting, because
it helps to confirm that bends should also be of constant radius. But on
British roads it is normal for the entry, or transition, curve to be a
spiral. The resulting shallow curvature of the tangent point can deceive
a driver into entering a bend too fast, and is a major cause of accidents.
I experimentally modified three accident prone bends by slightly trimming
the inside of the road to remove the spiral and to give uniform, circular
curvature. Construction cost was minimal, and accident rate fell by 80 per
cent.
The rationale for using transition curves is dangerously flawed, and
originated in an inappropriate transfer from railway technology early this
century. Although standard in Britain, these curves are not normally used
in, for example, the US. A recent Californian study of several hundred bends
showed that they had 73 per cent more accidents with transition curves than
without, so their use was not recommended. In Britain, several thousand
casualties per year can be attributed to transition curves.
The response from our Department of Transport to the Californian report
was that its ‘current approach to transitions . . . is satisfactory’. Yet
the DoT has never investigated the effect of transition curves on accidents.
Douglas Stewart University of Aberdeen