Eyes down
As your correspondent points out, the advice to remember to blink frequently
while using a computer is not at all silly
(Letters, 18 July, p 56). The problem
of fixating on the screen and forgetting to blink is well known, and much effort
has been directed towards encouraging better ergonomic practice.
In particular, putting the computer on the desk and the screen on top of that
may mean that many operators are looking up to the screen and widening their
eyes in doing so.
Instead, we are advised to lower the screen relative to the keyboard, so that
the direction of gaze is between 10掳 and 15掳 below the horizontal. One
effect of this is a reduction in the exposed area of the eye, so evaporative
loss is reduced. It has also been found that this smaller opening results in a
thicker tear film.
These two effects greatly improve the stability of the film, and reduce the
risk of occasional film break-up and the formation of damaging dry spots on the
cornea.
Abnormal knees
The reason that Schwartz and his colleagues have found abnormalities in
magnetic resonance imaging scans of children’s knees
(This Week, 25 July, p 11)
may have something to do with the fact that the scans are apparently taken with
the children standing on their heads (see the picture).
If they took them in the normal orientation, things might appear
differently.
Princeton doubter
I am glad that you printed
(Letters, 11 July, p 59) my letter crediting the
late Cecilia Payne-Gaposchkin of Harvard for discovering that hydrogen is the
element that is dominant in stars. I mistakenly and absent-mindedly wrote that
it was Arthur Eddington who doubted her, when in fact it was Henry Norris
Russell of Princeton who held up acceptance of her revolutionary idea for
several years.
Letter
Richard Taylor traces the etymology of “bugs” back to the 1950s, but while
the computer variety may date from that era, technical bugs are much older
creatures.
According to Edward Tenner, in Why Things Bite Back: New Technology and
the Revenge Effect, the bug was well-established as a species by 1878, when
Thomas Edison wrote: “The first step [in the invention process] is an intuition
and it comes with a burst, then difficulties arise鈥攖his thing gives out
and then that鈥擿Bugs’鈥攁s such little faults and difficulties are
called鈥攕how themselves, and months of intense watching, study and labor are requisite before
commercial success鈥攐r failure鈥攊s certainly reached.”
Letter
A couple of years ago an ant colony took up residence in my PC. With ant
corpses festooning the motherboard and eggs in the CD drive, the effect was
terminal.
Just after I discovered the nest, a friend told me that he’d installed the
game SimAnt on his computer. I’m sure it was far more entertaining than
RealAnt.
Letter
I’ve never had spiders in my computer, but I have had carpet beetle larvae in
my video player. In this undisturbed habitat they found a good supply of fluff
to eat, and even the odd video to watch鈥攅ven if they died in the
attempt.
I never did manage to evict them, and got so fed up with ruined tapes and
cleaning the sticky mess off the video heads that I had to buy a new
machine.
Bugged machines
Richard Taylor is far from being alone with his spider’s web
(Letters, 18 July, p 56).
Now that PCs are no longer kept in a protected environment in
sealed rooms, they are as prone to infestation as any other equipment. And that
extra bite in a floppy disc may not be helpful.
Booklice, house dust mites, thrips and furniture mites commonly cause
problems, perhaps attracted by the heat generated, by scales of skin left by
operators, and by crumbs of food from those too dedicated to leave their
desks.
Spiders and thunderflies (thrips) can also activate movement detectors in
security alarm systems.
Clarifying californium
It seems, judging by your article at the end of last year, that the
well-established technology and applications of californium-252 neutron sources
are not widely known
(“Neutrons for sale”, 13 December, p 32).
You state that californium produces no more than 107 neutrons per second and
requires special handling facilities for the “gas”. In fact, the Radiochemical
Engineering Development Center at Oak Ridge National Laboratory in Tennessee can
load enough Cf-252 into a cylindrical capsule 5 centimetres long and 1
centimetre in diameter to produce more than 1011 neutrons per second.
Californium does not exist as a gas except at extremely high temperatures,
beyond those encountered during source fabrication or accident conditions.
Although some companies may be reluctant to handle “radioactive gases”, sealed
capsules containing Cf-252 sources are remarkably durable and have successfully
withstood tests involving 10 pounds of high explosive, aviation fuel and oil
well fires. They have even survived being run over by railroad cars and shot out
of a 50-calibre machine gun into a concrete wall.
Although the article correctly points out that neutron sources with an on-off
switch (fusion devices and accelerators) have advantages, californium remains
very cost-competitive as a continuous, maintenance-free source over a wide range
of neutron source intensities. Californium is widely used for non-reactor
neutronics and commercial applications such as nondestructive and on-line coal
and minerals analysis, landmine and unexploded ordnance detection, neutron
calibration and dosimetry standards, and cancer therapy.
Because californium remains the standard for evaluating new developments in
neutron source technology, attempts to undersell californium’s capabilities as a
way to oversell competing technologies are not surprising.
Symptomatic lice
What is consistently overlooked in the issue of the decline of sea trout in Scotland
(This Week, 4 July, p 23)
is that two separate questions are involved.
Do sea lice from farmed salmon find their way onto wild sea trout? Are sea
lice the root cause of the decline in sea trout populations?
The answer to the first is undoubtedly “Yes”. Given the numbers of larvae
released from salmon farms, it would be strange indeed if some of them did not
attach themselves to sea trout.
The second question is more difficult to answer, and the evidence collected
to date is contradictory and inconclusive. What is certain is that ectoparasites
such as sea lice thrive on sick and stressed fish. Indeed, ectoparasites are
increasingly being used as indicators of environmental change, particularly
pollution. The presence of large numbers of lice on sea trout can therefore be
interpreted as evidence of an environmental problem.
Is it not time that we put more effort into identifying the nature of this
problem rather than concentrating on what is probably its most obvious
symptom?
Plague of caterpillars
Alaskan forests are not alone in suffering the ravages of munching
caterpillars
(This Week, 18 July, p 12).
This spring, the Cumbrian fells in Britain were infested with vast numbers of
antler moth caterpillars (Cerapteryx graminis), which ate the
vegetation normally grazed by sheep. As in Alaska, it has been suggested that
this caterpillar plague was caused by abnormal weather.
Mind games
I agree that antidepressants may be no more effective than placebos, but this knowledge may not have simple implications (Editorial, 11 July, p 3, and This Week, p 13).
As a GP starting out 14 years ago, I had great faith in antidepressants. I prescribed them confidently and they worked. I then developed my counselling skills and used medications less and less. This also worked. Adding antidepressants did very little and I usually ended up stopping them and continuing with counselling alone.
This experience, as well as some literature research, resulted in my concluding that they probably worked by placebo effect only. My confidence in antidepressants plummeted. I could no longer prescribe them and earnestly promise efficacy. I still promised, but I am not a good actor-the earnestness was gone. They hardly worked.
Recently I have done more research on the placebo effect and I believe it is more efficacious than I first thought. My faith in antidepressants is therefore restored. I can now prescribe them with confidence and expect them to start working again.
Unfortunately, I’m unable to do the necessary study-a trial of placebos versus placebos where half the people being tested are told they are on an ineffective pill, and the other half are told they’re on a fantastic treatment. This would be revealing, but unethical.
Why don’t the pharmaceuticals companies release their placebo pills onto the market and call them “Obecalp”? I’d prescribe them all the time.
Cars for all
It is almost a defining characteristic of governments that they expect to be
able to legislate for water to flow uphill, but it is surprising that your
editorial and Mick Hamer’s article are so uncritical of John Prescott’s
desperately ostrich-like transport initiative
(Editorial, 25 July, p 3, and
This Week, p 5).
I would suggest that there are two unassailable facts that have been ignored.
First, public transport initiatives tend to have only a local impact on road
traffic and even then not an absolute impact鈥攔oad traffic may be removed
from the city centre only to appear instead in the suburbs, on routes to and
from the new light railway’s car parks, or whatever.
Second, such schemes affect far too small a percentage of the populace.
Banning cars from central London would undoubtedly increase the ease of Cabinet
ministers’ chauffeur-driven rides to Whitehall, but would have an insignificant
effect on traffic levels across the nation as a whole.
The flaw lies in believing that tinkering with the supply of public transport
will answer the demands of citizens who want personal transport. Isn’t it time
we accepted that people want cars and therefore that in a democracy there will
be more cars in the future?
Let’s turn our attention to developing the transport mechanisms we want:
giving everyone equal access to personal transport; designing, manufacturing and
operating cars to be less environmentally expensive; designing and managing the
road network in a way that doesn’t introduce congestion and delay.
Letter
Our battle against bacteria may have backfired. This strikes a chord with H.
G. Wells’s War of the Worlds. But instead of Martians eliminating their
own bacteria and invading Earth, it’s us who seem to be eliminating our own
bacteria and planning to invade Mars.
Letter
This explains why dropped toast always lands buttered side down. It is
nature’s way of ensuring it picks up enough germs to keep us healthy.
Letter
The best answer in Britain would be for the government to get behind city
farms, which always seem to be struggling, and make them into an important
feature.
At the age of two, there’s nothing like getting your face into the hide of a
goat or donkey to promote psychological and physical health.
Letter
I grew up on a farm in North Yorkshire in the 1950s and early 1960s
surrounded by animal manure. I always seemed to be hungry and, unbeknown to my
family, regularly ate a delicious pottage of boiled potato peelings and
vegetable scraps that my grandmother prepared in an old copper boiler for our
free-range chickens.
The dirt from the peelings was never removed and formed a scum on the surface
of this soup. I also used to regularly munch on cow cake as a dietary
supplement.
I have always credited this bacteria-rich upbringing for my strong immune
system and hardly any sickness during my 48 years.
Munching muck
Theories about excessive hygiene just don’t hold up in my case
(“Let them eat dirt”, 18 July, p 26).
I grew up in the east end of Sheffield in the 1950s when that area abutted
the Don Valley steelworks. We lived in an old terraced house in a grotty street
forever shrouded in a dirty fog.
As a result of this delightful environment I caught, in rapid succession,
polio, whooping cough, mumps, measles, scarlet fever, chickenpox and glandular
fever, between regular bouts of tonsillitis.
Once we moved to the south of Sheffield, on a new leafy housing estate, my
childhood illnesses were reduced to the odd cold, twice a year.
Letter
Nuclear power stations’ primary protection systems are completely analogue
and are no more sophisticated than a couple of bits of wire connected to trip
units, so the millennium bug is irrelevant.
Furthermore, all nuclear reactors in this country have a big red button
within easy reach on the operator’s desk. Pressing this button unlatches the
rods and instantly shuts the reactor down.
Personally, I’m a coward and wouldn’t go anywhere near anything I thought was
dangerous, so I chose to work at a nuclear power station.
Fully prepared
Your article states that a serious accident could occur in the nuclear
industry because of the millennium bug
(This Week, 25 July, p 13).
In fact, for some time the British nuclear industry has had programmes in
place that address the millennium. The programmes include the systematic
investigation, testing and assurance of all process control, safety and business
systems. Modification or replacement of components or systems will be undertaken
where necessary. These programmes are formally reviewed on an ongoing basis by
the industry regulators. The British nuclear industry is also working with
suppliers and contractors to ensure that their systems are
millennium-compliant.
Indeed, the British nuclear sector is playing a leading role in preparations
for British utilities as a whole. The industry recently hosted a conference to
promote worldwide best practice and meet the millennium challenge. Britain’s key
nuclear operators were asked last year by the Health and Safety Executive’s
Nuclear Installations Inspectorate to include millennium bug matters in their
safety cases. It has also indicated that the British nuclear industry is
addressing the challenge satisfactorily.
Gaian engineering
James Lovelock asks the question: “How can evolution by natural selection
lead to a planet with a self-regulating environment?”
(Letters, 11 July, p 57).
As an electronics engineer I can answer that question easily: any complex system
with many feedback loops will display rapid transitions between unstable states,
and frequent but small noise-induced perturbations in stable states.
An observer is therefore very likely to see an apparently self-regulating
system at any given instant, but may see sudden transitions to other stable or
metastable states if he waits long enough (or looks back far enough). External
influences (for example the Sun) can induce decaying perturbations or trigger
sharp transitions, depending on their magnitude, timing and nature.
No external control or preprogrammed thermostat is needed鈥攊t is simply
an inevitable effect of a complex feedback system. Whether you call this Gaia or
not, it appears to be how our world behaves.
Political maelstrom
Hutton Archer of the Global Environment Facility secretariat claims that it
is doing its best on biodiversity and that there is no evidence to the contrary
(Letters, 11 July, p 58).
But both your original article (This Week, 6 June, p
18) and Archer’s public-relations response fail to mention the politically
hazardous context within which the GEF must work.
Created by European governments to pre-empt more radical ways to finance the
climate change and biodiversity conventions, and asked to green the World Bank
and bring UN agencies together on the environment, the GEF is at the centre of
many conflicting political and institutional pressures.
It must meet vague guidelines from the conferences of the parties to the
conventions while remaining responsive to implementing agencies (the World Bank,
UN Development Programme and UN Environment Programme), powerful donor and
recipient member governments, a vociferous nongovernmental community and various
shadier interests represented on its senior advisory panel.
Therefore, long before global science鈥攊n the shape of its
UNEP-administered scientific and technical advisory panel鈥攇ets a look in,
the GEF has had to “sensitively” select projects for funding. Which means it
must be all motherhood and apple pie in public while the real deals are cut
elsewhere.
The fate of the environment, global or otherwise, tends to be something of a
side issue as this relatively new institution tries to keep a toehold on its
fragile niche in a competitive bureaucratic “ecosystem”鈥攚here conservation
priorities cannot but be some way down the pecking order compared with economic
values and political necessities.