Wash'n'dry
Your Patents column mentions inventor Raymond Johnson’s claim that millions
of cases of food poisoning in the food industry and cross-infection in hospitals
result from improperly washed hands
(This Week, 12 December 1998, p 11).
However, it has been known for some time that drying your hands is more
important than washing them. Wet, well-washed hands can transmit as many as 60
000 microorganisms on contact, whereas similarly washed hands that have been
thoroughly dried transmit a mere 200鈥攖his from a study reported in
Antipodes in your Australian edition
(“Wet hands given a towelling”, 13 June 1998, p 50).
Moisture is an effective medium for the transfer of microorganisms, and since
it is almost impossible to get hands absolutely clean, stopping the bugs being
transferred to other surfaces is a more effective way of dealing with the
problem than washing per se. Ideally, hands should be dried with a towel
followed by hot air drying.
Johnson’s patented device for detecting improperly washed hands using
coloured soap and a video camera would do better if set up to detect improperly
dried hands鈥攕omething which is surely within the capabilities of the same
technology.
Letter
There are two problems with chairs that are not mentioned in the article.
The first is that chairs are often too small for those sitting on them,
meaning that the angle between back and legs can be much less than 90 degrees.
I, a six-foot sixth former, am expected to spend all day sitting on chairs
designed for people a foot shorter than me.
Second, one particular area in which using standard chairs is simply
ridiculous is in an orchestra. For wind players, it results in the well-known
squashed lungs. For string players, careful arrangement is needed to ensure that
the bow does not collide with your legs. For all, sitting in right-angled chairs
results in bad posture and back problems.
Some musicians use blocks to tilt their chairs forward to alleviate the
problem, but this doesn’t help if the chairs are too short in the first
place.
Floored by chairs
As a third-year undergraduate, most of my life involves sitting with my torso
at 90 degrees to my legs in computer labs, lecture theatres or the student bar.
I welcome the advice in your article on the perils of sitting to make this angle greater
(“The only good chair”, 19 December 1998, p 76), although whether this
would alleviate or antagonise lower back problems is another matter.
Last year, one of our lecture blocks was refurbished with cinema-style,
flip-down seats. Being designed by fine human engineers, the hinge, which locked
at 90 degrees in the first week, locked at 95 degrees in the second鈥攁nd
the angle steadily increased until the end of term.
By this time the seats resembled the Swedish “perching chairs” in which the
user/victim is gradually tipped forward onto the floor while their trousers ride
high into an eye-popping wedgie. In light of your article, I must consider this
progress.
Heavenly halos
Further to your item on circular rainbows in the Last Word
(19 December 1998, p 84):
in Scotland, the circular halo often seen round the Sun, and particularly
the Moon, is known as a broch. It is caused by light being reflected by
otherwise invisible ice crystals in the atmosphere.
The higher this layer is in the atmosphere, the closer the halo, (or broch)
appears to the Sun or Moon. Hence the old and trusted saying: “Broch be near,
storm be far; broch be far, storm be near.”
Thinking machines
I believe Michael Cross is mixing up two completely different things in his
article on the possibility of building a conscious computer
(Forum, 28 November 1998, p 52).
He speaks of a “Turing machine” as having “functions
indistinguishable from a conscious entity”. However, I think he meant to refer
to “a machine that can pass the Turing test” rather than a “Turing machine”.
The Turing test is a test conceived by Alan Turing in which people are asked
to communicate with a machine and a human being, not knowing which is which, and
pick out the machine. A Turing machine is something completely different, namely
a theoretical description of a conceptual universal machine.
Land of opportunity
A truly homogeneous population provides a unique opportunity to extract new
knowledge with implications far beyond current comprehension.
The Icelandic genetic database is therefore among the greatest revolutions
ever in medical history
(Editorial, 5 December 1998, p 3 and
This Week, 5 December 1998, p 20).
As such, the Icelandic initiative should be treated with admiration and respect,
and the authorities given due support. The outcome will doubtlessly benefit not
only Iceland, but the whole of humanity.
Creeping radiation
After the recent finding in the US that radioactive waste can effectively
clamber up tree roots and thus reach the surface, Tam Dalyell asked British
Nuclear Fuels (BNFL) about the situation here
(Thistle Diary, 5 December 1998, p 51).
Reading that a BNFL director, Colin Duncan, told him that “now we know the
mechanism, measures can be taken to stop it happening” sent a chill through my
body. What other mechanisms do we not yet know of?
Why do those responsible for the disposal of nuclear waste always
underestimate the natural world? Bacteria, slimes and all plant life migrate.
That is nature.
This is a long-term problem, and I am not persuaded that BNFL and the others
fully recognise it. It is in my interest as a retired long-term nuclear industry
employee and local resident that they do.
Tobacco doublespeak?
I am flummoxed by the logic in your feature on smoking in China
(This Week, 28 November 1998, p 18).
Paragraph four states of Richard Peto: “And he argues that almost no disease
has a single cause and that it is bad science to suggest it does.”
By paragraph nine, you say of Peto’s second “smaller” study: “Both
investigations show that today about 12 per cent of Chinese male deaths are
caused by tobacco.”
Is this Orwellian “doublespeak”?
Home testing
In a short article, you report that a home urine test could give diabetics an
accurate analysis of their glucose levels
(This Week, 12 December 1998, p 19).
However, for many years urine sugar measurements have been superseded by
blood glucose measurement for home monitoring of diabetic patients. This gives a
much better indication of patients’ status “now”, as opposed to what it was up
to four hours ago as revealed by a urine test.
Blood glucose devices for the home can, with proper training, give results
almost as accurate as hospital-based machines. These sensors cost a mere
拢30.45 and give a result seconds after blood is applied.
Blood tests are indeed better for people with severe diabetes who need
up-to-the-minute information on their glucose levels. The sensor described is
intended for mild diabetics who prefer urine tests to the discomfort of taking a
blood sample鈥擡d
Sex is best
To most evolutionary biologists with an interest in sexual reproduction, the
high mortality rates among cloned mammals will be a relief rather than a puzzle
(This Week, 19 December 1998, p 4).
There has been a long-standing debate about what factors counter the
“two-fold cost of sex”. This cost refers to the fact that a female reproducing
by parthenogenesis鈥攊n which unfertilised eggs develop into
adults鈥攚ould usually pass on twice as many of her genes per generation as
a sexually reproducing female. The selective pressure against sexual
reproduction is therefore strong.
There are two main reasons why sexual reproduction might be maintained in
populations despite this cost. The first is that it produces resistance to
parasites, through the mixing of defence genes to give combinations to which
parasites are not adapted.
The second concerns the mutational load in populations. According to this
theory, sexual reproduction can remove deleterious mutations when, by chance,
they get lumped into what might be termed a “sacrificial lamb”, a hopeless
genome which cannot function but allows the production of genomes with no
deleterious mutations. Experiments with fruit flies show that the mutational
load may well be high enough to support this theory.
During the growth of multicellular organisms, mutations occur in somatic cell
lines, producing an organism with a mosaic of cells that are slightly different
to each other. Blemishes such as birth marks or moles in humans are an example
of this. A large proportion of mutations with a phenotypic effect will be
deleterious, so when a cell is selected for a cloning experiment there is a
chance that this cell will have suffered a deleterious mutation, and the
resulting clone will not survive.
During sexual reproduction, on the other hand, these mutations are weeded out
through the production of gametes and the shuffling of genomes. There is also
some evidence that mammals “test-drive” embryos by stressing them, to remove
substandard genomes. Natural abortion rates are thought to be between 30 and 80
per cent in humans.
So the failure of many clones is not in the least surprising, and supports
one of the main theories for the maintenance of sexual selection.
Steer clear of bats
Your article on fruit bats made compelling reading and captured something of
the dismay experienced by bat biologists (including myself) when it was first
discovered that Australian bats carry life-threatening diseases, just as they do
on other continents
(“Bats out of hell”, 5 December, p 40, and Letters, 9 January, p 48).
Coming just days before the second human death in Australia from lyssavirus,
the article was prophetic and underlined the need for the public to be well
informed about bat-borne diseases, so the risk can be minimised.
Some bat devotees have sought to downplay or deny human health risks because
they see more need to protect bats from the public than the public from bats. To
me, this is neither ethical nor conducive to scientific credibility, and could
easily result in increased persecution of bats by a public that thinks it has
been misled.
One point not discussed in the article is the threat posed to bat populations
by human or human-borne disease from other captive animals. There seems little
doubt that the best policy is to keep bats (and other wild animals) and people
at arm’s length.
Letter
Incompatibilities between paternal and maternal imprinted nuclear genes could
also explain developmental problems in cloned animals as well as the size
disparities found when different species of mice are crossed
(This Week, 12 December 1998, p 16).
However, we shouldn’t forget another possibility. Some of the proteins that
make up mitochondria, the powerhouses of cells, are coded for by DNA found in
the mitochondria, whereas others are coded for by DNA in the nucleus. Size
disparities may result from a lack of concordance between mitochondrial proteins
from these different sources. Optimal mitochondrial function is essential for
normal growth and function.
The strict requirements for harmony between the nucleus and mitochondria have
been demonstrated in cell systems as well as in whole animals. This should be
borne in mind when discussing cloning and the rather scary issue of human embryo
“rescue” by cytoplasmic transfer.
Meaty myth
Rosalind Riley suggests that if everyone stopped eating meat, or at least
reduced their meat consumption, it would help solve the “world food problem”
(Letters, 21 November 1998, p 62).
This simplistic solution is frequently
suggested, but its promoters should bear in mind the following:
Meat from ruminants such as cattle and sheep can be produced without grain.
To state that it requires “16 pounds of grain to produce a pound of beef” is
incorrect. In New Zealand, for example, cattle receive little or no grain.
In North America, cattle do receive large amounts of grain, and the farmers
can make more money by selling their grain as cattle feed than by selling it
directly. If the demand for meat was reduced, the farmers would either stop
farming or switch to something other than grain.
Farmers in North America (and Europe) could double or triple agricultural
production if there was an incentive to do so. The “world food problem” is not a
production problem鈥攊t is a distribution problem.
Quantum Christmas
I have recently received a number of distinctly unfestive e-mails pointing
out the impossibility of Santa Claus delivering presents to all the children in
the world in just one night.
We are all aware of the flaws in the conventional Santa Claus theory, but
seem to accept it quite readily. Children are not quite so gullible and require
a more rigorous proof of his existence. The answer to this problem lies in
quantum theory.
Consider this: On Christmas night, Santa is in a superposition of quantum
states, smeared out all the way round the planet, and each quantum state
delivers presents to a single child. This explains why it is so important that
children are asleep, because if just one child sees Santa, he immediately
collapses into a single state, in accordance with Heisenberg. This would mean
that no other children would receive presents that Christmas.
This theory elegantly avoids all the flaws in the conventional theory. The
only problem is that you will have to explain quantum theory to your children
before you tell them about Santa.
Trolley triumph
Airport and supermarket trolleys with four caster wheels may be difficult to control
(Letters, 19 December 1998, p 104), but there is a reason for having
them. When several trolleys are nested together, they can still be steered,
after a fashion, by the staff. Having fixed wheels, either at the front or the
rear, would make this impossible with more than one or two nested trolleys.
At Athens airport, they have found a solution to this problem. Each trolley
has a fixed front wheel which is raised off the ground when it is nested with
another trolley. A caravan of nested trolleys thus has a single fixed wheel at
the front and many caster wheels behind.
I had been thinking about this problem and was considering some sort of
wheel-locking mechanism that would be released when the trolleys were nested,
but whoever designed the trolleys for Athens airport has come up with a simpler
and more elegant solution.
Letter
The Mandal chair, with its sloping chair and desk, has another, less obvious
benefit besides reducing the strain on your back. There is all the exercise you
get from having to repeatedly pick your pen and pencil up from the floor as they
keep rolling off the sloping desk.
Behind the times
Cunning old New 杏吧原创! According to your Christmas Editorial
(19 December 1998, p 3),
you are still using the Julian calendar. That means you
won’t get zapped by the millennium bug until nearly two weeks after the rest of
us, who have stupidly been using that new-fangled Gregorian version since 1752.
All the best for 1999, whenever it begins for you.
Cold comfort
Your article on snowmen (“Meltdown”, 19 December 1998, p 46) left out one
particularly poignant literary reference鈥攖hat of St Francis’s snow family.
It was recorded that once he made a wife and children out of snow and claimed
that that would have to be enough for him. Mere loneliness might be enough to
make one want to build a snowman, or indeed to create any image.
That minor bug
Yesterday I received my car insurance renewal certificate. Guess what: the
insurance starts on 12 January 1999 and expires on 11 January 1900.
I rang the broker, who shall remain nameless, to check that the insurers
weren’t going to try and weasel their way out of any claims on the basis that my
cover expired 100 years ago. The voice on the other end read out what was
obviously a prepared statement:
“[The broker] and [underwriter] can both assure you that all their IT systems
are fully millennium-compliant. The expiry date of 1900 on your insurance is
merely a minor bug that was introduced when we started issuing certificates with
expiry dates in the year 2000.”
Maybe I should start telling my boss that the code I write is fully
millennium-compliant too. Oh, except for a minor problem鈥攖hat it might not
work correctly after 2000.
Correction:
In “The tortoise and the hare”
(The Year in News, 19 December 1998, p 34),
it was wrongly stated that the human genome has 30 billion
base pairs. The figure should have been 3 billion.
Letter
Regarding your points about the Chinese New Year: the Year of the Rabbit runs
from 16 February 1999 to 4 February 2000, after which it is the Year of the
Dragon up to 23 January 2001.
The Chinese will regard the new millennium as starting with the Year of the
Dragon. Appropriately enough, this is “a year marked by a lot of surprises and
violent acts of nature. The electric atmosphere created by the mighty Dragon
will affect us, one and all”, according to The Handbook of Chinese
Horoscopes by Theodora Lau.
Good timing for a millennium bug, eh?