ÐÓ°ÉÔ­´´

Letters : . . .

Correction: The item “Neutrinos reveal the Sun’s secret heart” (New
ÐÓ°ÉÔ­´´, Science, 21 September, p 20) stated incorrectly that the
experiment in the Homestake mine detects neutrinos using a large tank of oil. In
fact, the tank contains perchloroethylene. Neutrinos passing through the fluid
cause the production of argon gas.

Letters : Pigeon pie

Cardiff

Regarding your article on Berlin’s pigeon problem (Feedback, 21 September p
88), you state that the authorities are to spend £17 000 every three
months on pigeon contraceptive pills in order to reduce the current population
of 6000 by half.

I would like to volunteer my services to do the job for £8 500 every
three months (a saving of 50 per cent). My technique of population control for
the “flying rats” is a little simpler. Just give me half an hour and a shotgun.
I’ll even sweep up afterwards.

Anyone know where I can buy 500 kilograms of shortcrust pastry?

Letters : Creating Darwin

Taunton, Somerset

Stephen Jay Gould is my idol: the author above all others who would accompany
me to my desert island. He is obviously a scientist of unimpeachable integrity,
and would go to the stake rather than fiddle a quotation to fit his own
doctrine.

In his third essay in Dinosaur in a Haystack, he concludes by
quoting Darwin’s final sentence in On the Origin of Species, as
capturing the essence of Gould’s most cherished tenets, and it reads:
“…life, having been originally breathed into a few forms or into
one”.

My edition of Darwin appears to be a “popular impression” of 1920 (I won it
as a school prize in 1933). In this edition the last sentence reads “originally
breathed by the Creator into a few forms or into one”.

I would really like to know how and when the Creator got in. Did Gould leave
him out—perish the thought!—or did some pious prat working for the
publisher of my edition slip it past the proofreader?

Letters : . . .

Lockerley, Southampton

Andrew Pomiankowski reviewed Darwin’s Black Box: The Biochemical
Challenge to Evolution and considered that the author, Michael Behe, has
attempted “to put God back into nature” (Review, 14 September, p 44). He
continues: “But don’t be fooled by his claim that molecular systems are
irreducibly complex, or that a supernatural designer is needed.” In the second
paragraph of the review is this statement: “Darwin knew all about the problem of
`organs of extreme perfection and complication’. He devoted a brilliant chapter
to them in On the Origin of Species.”

Let us look at this brilliant chapter. Consider the paragraph starting with,
“It is scarcely possible to avoid comparing the eye to a telescope.” Later we
find this: “Have we any right to assume that the Creator works by intellectual
powers like that of man?” Then at the end of that paragraph: “…and may we not
believe that a living optical instrument might thus be formed as superior to one
of glass, as the works of the Creator are to those of man.”

Now turn to the last paragraph of every edition of the book: “There is
grandeur in this view of life, with its several powers, having been originally
breathed by the Creator into a few forms or into one.”

A designer or a Creator—what is the difference?

Letters : Wrong primate

London

Presumably Kate Charlesworth, in “Life, the Universe and (almost) everything”
(31 August, p 45), intended to compare the galago’s brain size to that of a
marmoset.

A marmot is not a “higher primate”. It is, I understand, a rodent.

Letters : Bomber magpies

Kuching, Sarawak, Malaysia

Magpies certainly attack small boys during the nesting season (This Week, 31
August, p 7) but from my experience as a small boy many, many years ago in
Wollongong, New South Wales, they did so most often because of
provocation…by small boys.

The thrill of being dive-bombed by a magpie, and the associated attempt to
try to crash the bird with a branch raised above your head at just the right
moment (signalled by your mates from safety), was well nigh irresistible. We
never succeeded in the latter attempt—which bears witness to the excellent
manoeuvrability and climbing powers of magpies.

Magpies tend to nest in tall trees commanding a good view of the
surroundings—a common situation in urban developments where only a few
trees are left standing. They will, in my experience, attack anything which
approaches the nesting tree. People, other than small boys, and animals such as
dogs and cats quickly learn to give the tree a wide berth.

Magpies are also “magpies”—they collect brightly coloured objects,
mainly white or blue, and will do so even at some danger to themselves around
the nesting season. Thus reflections from a bald man’s head or baubles on a pram
are more likely triggers for attacks by magpies than memories of past
chick-stealing by senior citizens or nursing mothers.

In those years so long ago, we small boys all knew that girls dressed in all
their finery for going out on a Saturday afternoon were in danger quite some
distance from the tree, far farther than on weekdays on the way to school.

Letters : Beneficial bees

Redmarley D’Abitot, Gloucestershire

Your feature article “The sweet smell of death” (7 September, p 28) raises
questions relating to the effect of changes in aphid-deterrent plant odour on
beneficial insects.

The yield of many crops, including field beans, is not only dependent on
fertility and the absence of pests but also on pollination. The Ministry of
Agriculture, Fisheries and Food has this year informed farmers of estimates
suggesting that they can greatly increase their yield and their profits by
having beehives in their fields, even allowing for the usual fee for the service
to the beekeeper.

There is no mention in Stephen Day’s research paper on how plant odour
changes affect bees and other pollinating insects, which would seem essential
before persuading farmers to experiment blindly with this interesting
technique.

Letters : Wish you were here

Scott Base, Antarctica

Just one small comment I would like to make concerning that almost excellent
Forum article written by Phil Bagnall (Forum, 6 July, p 45).

Phil, your essay on time did while away the time for a short time. But, if I
were an Adélie penguin, you’d make my quills stand on end with your
comment: “It is even possible to holiday in Antarctica. And so people
do—although heaven knows why.”

Firstly, I apologise for my late response to your essay. We just had our
August Starlifter (C141) supply flight and it’s taken about two months for
New ÐÓ°ÉÔ­´´ to finally make its way down here to Ross Island. Phil,
please come down to Antarctica and experience Antarctic tourism at first hand
before making such sweeping, hopefully tongue-in-cheek statements.

Letters : Not so secondary

Southampton

We were astonished that Stephen Wolfram thinks most of the important research
in his field is done by industry and that “universities are pretty secondary
entities” (“Millionaires’ row”, 14 September, p 33).

Is he not aware that Mathematica’s nearest competitor, Maple, was developed
in 1980 at the University of Waterloo, Canada, and continues to be closely
associated with the university? Or is this a subtle attempt to discount the
competition?

Letters : Proper path

Upwey, Victoria, Australia

Dan Thisdell says that the critical path is “the theoretical shortest
distance between the start and finish of a manufacturing project” (Review, 31
August, p 40).

Distance? Shortest? In a properly joined network of all the relevant
activities making up a project, if each activity is measured by the time it
takes to complete it, the critical path is the longest path—measured by
time—through the project (that is, from start to finish).

That path also happens to be the shortest time it will take to complete the
project, which is probably where the confusion arises. (Another part of the
definition of “critical path” states that a delay of x time units to
any activity on the critical path inevitably results in a delay of x
time units to the entire project.)

While we’re on the subject of engineering terms, could you also remember that
“learning curve” is both a misnomer and a record, not a prediction. The
so-called learning curve shows how long it took (not will take) for you (or
whoever) to learn how to do a new task efficiently. You start with 0 per cent
proficiency and end with 100 per cent proficiency. You cannot know how long that
will be until you’ve finished learning.

As it is impossible to say exactly when you had, say, 50 per cent or any
other degree of partial knowledge, the learning curve might just as well be a
straight line, not a curve. What’s more, the steeper the line the better. It
means you achieved 100 per cent proficiency in a shorter time than you would
have done if the line had been shallower.

Letters : Aliens welcome

Berkhamsted, Hertfordshire

John Drewett is clearly a Vulcan infiltrator (Forum, 14 September, p 48). His
proposal that there should be mandatory controls on alien species is as
unearthly as it is arrogant.

Emotional, biophilic bonds between humans and wild creatures—ruddy
ducks, say—are part of local ecologies, just as alien species are often
crucial colonisers of degraded land. Indian balsam, for example, berated “as
detrimental to the native flora”, is often naturalised by the side of grossly
polluted rivers where more sensitive plants have long vanished. And, in
spectacular flower right now, long after most “native” species, it supports a
vast array of autumnal insect life.

Our lot, simply by being an island in a rapidly changing climate, is to face
a remorseless trickle of wildlife extinctions. If it were not for an equally
steady trickle of opportunist colonisers—escapees, stowaways,
naturalisations—our wildlife estate would become progressively more
impoverished and predictable. We should be grateful for their resilience.

Letters : Carping comments

Bristol

Is anybody safe from the snide carping of the people who write for your Forum
section?

On 21 September (p 56) it was artists, Damien Hirst in particular, who came
under assault. Jeremy Burgess may have had his tongue in his cheek, but the
argument was the same as usual—a denigration of another community based on
a completely garbled conception of what it does, followed by the arrogant
assertion that scientists could do better.

Another example was “The trouble with philosophers” (6 July, p 44). A more
ignorant argument than this would be hard to find, especially the assertion that
it is impossible for a heavier mass to orbit a lighter one.

Other groups who have come under attack include ethnographers and
sociologists. Who is next in line to be “sorted out” by your correspondents?

It is not the ideas themselves that I object to, but the way they are
expressed. They are usually the frenetic expression of an inferiority complex
amongst sections of the scientific community.

I have argued myself that the Arts Council should support science, but the
way Burgess wilfully misunderstands art only detracts from many inspiring
projects which bring science and art together.

More seriously though, misinformed attacks on other groups, even in fun, make
scientists look both arrogant and parochial at a time when they need to be taken
seriously.

Letters : Running dry

Ashford, Kent

Fred Pearce seems to be saying that if there is lots of water under the
ground, all we have to do is pump it out and there will be no more shortages
(“Waters still run deep”, 3 August, p 24). But where does this water come
from?

Here in Kent we have several large aquifers—the porous chalk and
sandstone rocks are full of water to great depths—forming a very large
amount of water indeed. But we also have relatively low rainfall and many
boreholes. Already in parts of Kent the amount of water extracted is very close
to the amount reaching the rock from rainfall. It does not take much
arithmetical skill to work out that if the recharge is less than the extraction,
the water table will fall.

Do we want all our rivers and streams to be like the Darent, south of
Dartford, where overextraction is pulling the water table below the porous chalk
river bed and regularly causing it to run dry?

The truth is that there is not really a water shortage at all. We are just
using too much of it—and if we keep using more, at some point we will
reach the limit of the supply. The answer is to use less, not to extract
more—whether rainfall goes up or goes down.

Letters : Shame for sheep

Glasgow

Darryl Mead identifies predation as a possible way to control deer numbers
(Letters, 14 September, p 52). He suggests that “the critical short term
change…must be to reintroduce large native predators… In Scotland
this would mean the wolf, brown bear and the wild boar.”

If I were a reintroduced wolf, I’d forget about deer and concentrate on
sheep. They are easier to spot, cannot run as fast and cannot put up as much of
a fight. Reintroduction of wolves might work if the wolves can be kept in an
enclosed area (say an island) where there are enough deer to support a viable
wolf population and no farmed animals to tempt them from venison. Such places
may be hard to find.

Letters : Funnel it down

Barry, Glamorgan

Tam Dalyell writes that he is concerned to prevent air pollution by ships
(Thistle Diary, 14 September, p 50).

One way to do this would be to discharge exhaust gases underwater. Although
this might not be desirable in confined waters, in the open sea the pollution
would be diluted beyond trace.

If the gases were discharged from many small orifices spread over the hull
surface, their absorption by seawater would be enhanced.

Other benefits might accrue. A film of gas bubbles over the hull would reduce
the wetted area, and its compressible nature might dampen turbulence like the
skin of a dolphin; both effects would reduce hydrodynamic drag.

Also, marine organisms which have fouled the hull in dock might find the
environment sufficiently noxious to drop off again, reducing drag still
further.

Has this idea been tried and, if so, with what result?

Letters : Oodles of glues

Edinburgh

Andy Coghlan presents a fascinating picture of biofilm (“Slime city”,
31 August, p 32), but the idea of a single “glue” alginate is a gross
oversimplification. It is not the only type of glue. Biofilm bacteria produce a
wide range of exopolysaccharides (EPS) each with distinct chemical and physical
properties. Alginate lyases, which degrade bacterial alginates only to a very
limited extent, will have no effect on other types of EPS.

Other enzymes with unique specificities may indeed degrade the EPS and these
may come from the bacteria producing the EPS, but they are also commonly found
in bacteriophages. Use of both bacteriophages and their associated enzymes
provides yet another tool for examining biofilm structure.

Interest in biofilms is fortunately encouraging the study of mixed bacterial
populations after years of concentrating on Escherichia coli
microbiology, but perhaps we should look more closely at the myxobacteria,
populations of which have long been known to possess unique and intriguing
social behaviour. They may well show some similarities to biofilms, not least in
the adhesins and glues used to bind the cells together to form fruiting
bodies.