Knit wit
I enjoyed your article on knitting Klein bottle hats
(22/29 December, p 38),
although I think it is a bit much to claim they have only just been invented by
Cliff Stoll, since I have been making them for family and friends since the
early 1970s鈥攂ut perhaps not many people knew that.
My reason for writing, however, is not to lay claim to ownership of the idea
but to point out an interesting quirk of the knitted Klein bottle. When knitted
with horizontal stripes everything matches up nicely, but when the stripes are
vertical it becomes obvious that the surfaces, although they join together
neatly, are transposed.
Animals and mirrors
Your fascinating and disturbing feature on animals in captivity
(26 January, p 34)
refers to the use of mirrors in horses’ stables to mimic social
interaction.
Some time ago, I placed a sizeable mirror outside our house because I had
nowhere else to put it. Our two small dogs ignore it, but our two domestic ducks
carry on animated conversations with their images, regularly nap beside them and
occasionally look behind the mirror to see where their friends really are. A
white-faced heron that has taken up residence nearby also talks to his image
and, when he thinks it isn’t looking, darts quickly behind to attack
it鈥攍ooking greatly puzzled to find empty air.
McNothing
Feedback mentions McDonald’s “40312 possible combinations” advertising
campaign, and notes that “reader Sally Baker points out that in fact there are
only 255 possible combinations of eight foods”
(9 February).
Baker is not quite right: there are actually 256 possible combinations of
eight foods. She left out the most important combination鈥攏ot having any of
them at all. That’s certainly my favourite.
Senior chickens
Jimmy Shadbolt wonders how long a chicken should live
(2 February, p 52).
This depends on the breed. The large ones such as Cochins
and Brahmas rarely live more than five years, but the little bantams such as the
Dutch can go on until 12 or 13. Hybrid egg layers usually only manage two years
before they are worn out.
Incidentally, I am not only a vet, but also keep, breed, show and judge
poultry and am secretary of the Dorking Breed Club. Dorkings are one of the
oldest British breeds and live until they are 9 or 10 years old.
Letter
Glasgow Zoo’s website states that the laying life of a domestic chicken is
about 12 years. The website of People for the Ethical Treatment of Animals
(PETA) cites a lifespan of 12 to 15 years, while most other sites give figures
between 5 and 8 years.
The oldest chicken I have met was 10 years old. She had stopped laying a
couple of years earlier and was going bald, but appeared otherwise in good
health. This kind of lifespan seems to be in line with other poultry, taking
into account relative size. I know of a turkey that was still alive at 14, a
duck that lived to 9 and another to 20.
Letter
Your article stated that until now no crater was known that might be
responsible for the extinctions at the end of the Devonian 360 million years
ago. However, in Sweden, 250 kilometres north-west of Stockholm, there is the
Siljan Ring鈥攏amed after one of the lakes near the rim of the crater. It
dates from 360 to 370 million years ago and is about 40 kilometres across.
Although the Siljan crater is much smaller than Woodleigh, it might have
contributed to the Devonian extinctions. And the violent upheavals caused by the
impact can still to be seen along its rim, so at least the Siljan crater beats
Woodleigh from a tourist’s point of view.
Squeeze wheeze
Regarding your article about Eunok Jung’s experiments with the “valveless pump”
(2 February, p 39),
the water in the length of rigid pipe linked with the
flexible section will behave like a metal rod suspended between two springs and
will have its own resonant frequency.
Such oscillations will distort the flexible section and change its cross
section on each side. Phase differences between the frequencies of oscillation
and squeezing explain the flow reversal as the latter speeds up. The researchers
could save money by contacting a consultancy in fluid dynamics rather than
relying on DIY and reinventing the wheel.
Save our teddies and their bugs
What in the name of all that’s cute and cuddly did the teddy Nazis think
that they would find when they tested the teddies
(2 February, p 7)?
Just teddy organisms? Of course the average teddy harbours “bugs”.
Teddies and related species, Pandas, Piglets and the odd Noddy add a great
deal to cold, sterile waiting rooms. I suspect the waiting rooms of the doctors
involved in this teddy-bashing exercise need all the humanising a good scruffy
teddy can manage.
Soft cuddly toys and their relations are important “prods” for immature
immune systems. I have been active in healthcare for 30 years. An elderly
gentleman once explained: “If a child has not eaten his or her own weight in
dirt by the time they are two, they may not make it.” This man possessed far
more insight than these soulless GPs.
Who is next on their hit list? The Tooth Fairy? Heaven knows what she has
lurking on her wings.
No function
The ingenuity of biologists can always find an evolutionary function for any
trait, however slight and unpromising
(2 February, p 26).
This ingenuity has therefore made the general creed that there must always be
such a function irrefutable and, accordingly, meaningless.
Like the earlier belief in God’s all-justifying providence, this creed
persists simply as a matter of piety, producing empty speculation. Why shouldn’t
many traits have no significant evolutionary effect at all? This would be much
more compatible with the鈥攏ow widely accepted鈥攂elief in punctuated
equilibrium, with long quiet periods between disasters. Neo-providentialism is a
superstition that should be dropped.
Letter
Lynn Dicks is right to look for an evolutionary advantage to a mechanism that
seems to encourage inbreeding. But she is not necessarily right to assume (as
she seems to) that there must be one.
It could be that inbreeding is always worse for us, but that there is another
mechanism at work, giving us some other genetic advantage that just happens to
have the side effect of dampening our drive for outbreeding. It could be, for
instance, that the mechanism is primarily there to promote bonding between
parents and offspring, and thereby boost the numbers of offspring surviving to
create the next generation.
Shark fin cruelty
I was disappointed that New 杏吧原创 has again ignored sickening
animal cruelty
(2 February, p 6).
Your article offered a light-hearted appraisal
of shark-fin fishing, while ignoring the horrific reality of this practice.
Sharks are hauled into boats with massive hooks, dismembered of their fins
with crude knives or axes, and then cast into the sea where they suffer a
prolonged and painful death. As a rational publication that emphasises
progressive thinking, it is saddening that New 杏吧原创 often ignores
the moral dimension of factory farming and other animal treatment, while
constantly discussing the ethical concerns surrounding nuclear power,
genetically modified organisms or unconscious embryos.
Autopsy vote
I was most interested in the articles about post-mortems, particularly the
assertion that an opt-out scheme in Austria, Sweden and Switzerland resulted in
a much higher autopsy rate than the “compulsory in some circumstances only”
system operated in Britain and the US
(2 February, p 16).
I would like to draw your attention to the website www.autopsychoice.com,
which has been advocating such a system for over a year. The site is polling
visitors and displaying the results, and it also has links to government
materials.
I am confident that the introduction of an opt-out scheme that gives
individuals the freedom to express an absolute veto would improve the social
standing and working conditions of pathologists. Instead of being seen as
ghoulish butchers compelled by law, they would be seen as, and indeed be,
professionals performing a service for the deceased and their relatives.
Dare to mislead
Anyone who has read the research on DARE knows what a sham it is鈥攁nd
what a very expensive sham
(2 February, p 44).
DARE’s attempts to “educate” our children about drugs can have the
indirect effect of killing them. In effect, when you teach kids that cannabis is
to be lumped with heroin, crack, methamphetamine and all the other dangerous,
addictive and deadly substances (which cannabis has been proven not to be) the
murder begins.
Sooner or later many (most?) of those kids will experiment with cannabis.
They will learn the truth that it is relatively harmless鈥攁nd much less
harmful, dangerous, addictive and deadly than the legal drugs alcohol and
tobacco. They will conclude that they were lied to about heroin and everything
else. We now have record numbers of teen heroin deaths.
Crater confusion
We were surprised to read that an asteroid “wiped out huge swathes of life
when it collided with Earth 360 million years ago”
(26 January, p 11).
The resulting Woodleigh crater is apparently “120 kilometres wide” and the impact
happened at “the time of a mass extinction towards the end of the Devonian
period, when 85 per cent of all species were wiped out”. These statements are
not borne out by close scrutiny. Controversy surrounds the crater’s diameter,
and its age has yet to be determined accurately.
The Late Devonian date for Woodleigh is based on dating of clay minerals from
the shocked granitic rocks. But dating clay minerals is not considered a
definitive way of establishing the age of an impact event, since there are many
alternative interpretations for the origin of the minerals. The clays most
likely formed over a long period of time, probably due to a water-driven thermal
event that occurred some considerable time after the impact. Moreover, marine
fossil fauna from the Late Devonian in northern Western Australia shows that
there was not a single mass extinction event, but a number of smaller
extinctions, readily explained by earthbound processes.
Critics of the 120-kilometre-diameter interpretation鈥攁nd there are
many鈥攕uggest that it is nearer 60 kilometres in diameter, based on the
available geophysical data. The Woodleigh impact would indeed have “created one
hell of a bang”. Until we know when it happened, any purported association with
mass extinctions or global environmental effects is pure geofantasy.