Myriad myriadth
Mike Holderness is right to say that in 21st-century science big numbers are
more common than ever before
(28 April, p 45).
But he is a bit behind the times in his implication that the problem of
writing down and visualising such numbers is at all new.
Take Archimedes, for instance. Around 225 BC he showed that the total number
of sand grains that would fill the Universe (as then conceived) could be written
down if you used a number equivalent to 10(8 ^times; 1016).
Not having modern notation, he had to express this as “a myriad myriad units of
numbers of the myriad myriadth order of the myriad myriadth period”.
And in China before the 6th century AD, the anonymous author of the book
Shushu jiyi, “Memoirs on the mathematical arts”, constructed ways of
writing numbers up to 104096 with ease: he was almost certainly working
on the basis of Buddhist ideas imported from India.
Mathematicians all over the world in past centuries have often “boldly gone”
to places that practical scientists have only needed to visit fairly recently.
That is, of course, why it is worthwhile for society to continue to pay
mathematicians to go on doing apparently useless things.
Asking for trouble
I always find it amusing when scientists express how predictable something is
after the event. Perhaps we should invent a new word: “A team of scientists has
just postdicted a raging foot and mouth epidemic.”
However, David Tilman’s statement, “Epidemic losses of livestock are . . . a
predictable outcome of high animal densities and low genetic diversity”, is a
salient one
(21 April, p 11).
It is one we should keep in mind when a genetic
engineering company inevitably announces a new engineered sheep breed that is
resistant to foot and mouth and suggests it be the base stock of our national
sheep population.
The introduction of such a breed would offer a selection pressure that would
favour any virus that could thrive in such a consistent genetic
environment鈥攑erhaps a new strain of foot and mouth. Not only would our new
sheep have no resistance to it, but the new strain would also be one that our
already flagging vaccines could not stop.
Convenient births
Your correspondent John Crowhurst, commenting on the connection between
impaired mother-child bonding and epidural anaesthesia, has mixed up unrelated
issues
(21 April, p 54).
It is true that analgesics can be immensely effective in women who have
particular health issues that affect their ability to cope with pain. But these
women are in a small minority.
The increase in the use of anaesthetic is linked more to the increase in
induced births, which are associated with stronger contractions and more pain.
Induced births are being scheduled for the convenience of medical staff rather
than the mother and baby. Giving birth is not a pathological process but a
natural one.
It is also true that even low doses of epidural painkillers affect the
bonding process. Epidural anaesthesia reduces the cooperation between mother and
baby that can sometimes happen during birth, which is not always recognised by
medical staff. Long-term effects of epidural often include headaches and loss of
vitality for the mother鈥攃omplaints which are frequently ignored when
reported.
The increasing use of Caesarean section as an obstetric procedure holds even
greater psychological risks. Obviously Caesareans can save lives, but the trend
towards performing more of them is for the convenience of medical staff (and in
the US to avoid lawsuits) rather than to benefit mother or child. Caesareans
increase the risk of postnatal depression in mothers. Bonding is also often
adversely affected. Babies born by Caesarean are more likely to have
difficulties sleeping or feeding. They are also slower to develop some motor and
social interaction skills.
Your correspondent Angela Graham points out that women should be able to make
informed choices, but is unclear about what the choice is. Lack of bonding can
lead to a variety of asocial conditions in society as a whole as well as within
the family. This needs to be weighed against the benefits of reduced pain when
giving birth. Graham suggests that because we live in a “far-from-optimal
society” the net effect of bonding is somehow less important. I suggest the
opposite.
Balance upset
In his letter, Alan Herod points out important facts about the global carbon
cycle and climate change鈥攂ut draws dangerously erroneous conclusions
(28 April, p 53).
In the absence of large-scale human interference or natural environmental
change, movements of carbon between the atmosphere and land surface are roughly
in balance. Roughly 120 gigatonnes of carbon per year are fixed by vegetation
through photosynthesis, about half of which is rapidly returned from plants back
to the atmosphere and half enters the soil. In the long term, again in the
absence of external interference, soil moves towards an equilibrium carbon
content, with inputs from plants and outputs as CO2 from the activity
of soil organisms being approximately equal at 60 gigatonnes of carbon per
year.
Unfortunately, two factors have disrupted this happy
equilibrium鈥攄eforestation and the insertion into the atmosphere of fossil
carbon from coal, oil and natural gas that has been outside the biological cycle
for millions of years. In addition, there has in the past been some release of
carbon from soil caused by cultivating grasslands such as the North American
prairies.
The logical approach is to tackle the factors causing the disequlibrium, by
slowing deforestation and aiming for maximum replacement of fossil fuels by
renewables. In addition, it makes sense to adopt practices that increase the
amount of carbon held in soils and vegetation. The Intergovernmental Panel on
Climate Change estimates that there is potential for increasing land sinks by
about 100 gigatonnes in the next 50 years. This could be achieved by a
combination of reforestation, slowing deforestation and changes in agricultural
management.
All of these approaches are valuable because, given the political will and
financial incentives, they can start immediately and will deliver a range of
additional environmental benefits. But they are not alternatives to cutting
fossil fuel emissions. Soil and vegetation sinks will reach a new equilibrium
value after 50 to 100 years and then cause no further net removal of
CO2 from the atmosphere.
It's hot in space
How can 20,000 K be called relatively cool
(21 April, p 38)?
Background radiation is only 3 K, isn’t it? What temperature is the rest of space?
Stephen Battersby writes: As well as the 3 K background radiation,
intergalactic space is filled with a tenuous gas at millions of kelvin. Atoms in
a gas have to collide to emit radiation, and these widely separated atoms rarely
do, so they can’t cool down.
Who goes with you?
May I suggest an evolutionary advantage to the sense of a “presence” so
beautifully described in your article on religious feelings
(21 April, p 24).
In many cases, people who have survived exposure to extremes of danger have
described such a sense of an extra person with them. I think of explorer Admiral
Byrd in the Antarctic, and the members of the Shackleton expedition,
particularly during their walk over the uncharted mountains to the whaling
station.
Reading these stories, I get a strong impression that the sense of an extra
person gave them added strength, permitting survival under circumstances where
it seems almost impossible that anyone would have the endurance to survive.
In our world, only a few people are exposed to such extreme danger, but in
the world of early humans danger was a more normal part of experience. They
would secure real advantages from sensing a “friend in need”. One can surmise
that this sensation evolved from the sense of deep trust which pack animals
place in a strong leader.
Ill wind
I couldn’t help but laugh when I read your Newswire report on the “perfect” dirtstorm
(28 April, p 19).
American meteorologist Douglas Westphal said the
path of a dust cloud containing pollutants that has been drifting over the US
was “worrying”. He added that such events could become more common if China
maintains its rate of industrialisation.
That’s rich coming from the biggest polluters in the world. At least China is
going to sign the Kyoto treaty.
Safe vaccine
In his article on Peter Lachmann’s suggestion that prize animals could be
given immediate protection from foot-and-mouth disease by injection of antibodies
(7 April, p 17),
Andy Coghlan quotes Chris Bostock as being sceptical
because the serum from the vaccinated animals might still harbour the virus.
There is a simple solution to that perceived problem. The imine which is
currently used worldwide to kill the virus for the preparation of the
inactivated vaccines has no effect on the antibodies present in the serum. Hans
Bahnemann, my colleagues and I demonstrated this several years ago.
Consequently, I still think it’s a great idea. Emil von Behring, who used
this approach more than a century ago in the treatment of diphtheria, would have
approved. He was rewarded in 1901 with the first Nobel prize awarded for
Physiology or Medicine for this approach to disease control.
Healing oils
So “aromatherapy has no direct effect on the brain”
(21 April, p 16).
Who claims that it ever did? The choice of oils used in the German study appears
rather odd. I am unaware of any claims that these particular oils increase
reaction times.
It’s bad enough that we have people setting themselves up as aromatherapists
after a two-week intensive course, and the touchy-feely crowd making claims that
this or that blend of massage oil will settle a “nervous condition”, without a
research group following the same path. The knock-on effect of this piece is
that newspapers have been reporting that essential oils are useless when they
have undoubted benefits. Lavender is great for burns and I find tree oil far
better than anything my GP prescribes for athlete’s foot.
HAL's legacy
Microsoft does say that NT stands for New Technology but there is another
more persuasive derivation
(Feedback, 7 April).
Microsoft hired the architects
for Windows NT from Digital and these engineers wrote WNT as the nominative
successor to the Digital operating system VMS which they had previously worked
on.
In the same way, the name of the computer in 2001: A Space Odyssey,
HAL, was supposedly derived from IBM by changing each letter to the preceding
letter in the alphabet.
Terrifying ride
The efforts of the X-ride designers to create an unpredictable “head over
heels” effect in a revolutionary prototype fairground ride
(28 April, p 32)
have long been pre-empted by the Rocker Planes, which for many years formed part of
the annual fair that visited my town.
This ride consisted of a rotating ferris-wheel frame supporting independently
spinning cars for two people, each weighted at the bottom for self-levelling and
fitted with a dual foot-operated device which locked the car to its axle. Those
brave or foolhardy enough to entrust themselves to an expert rider could expect
not only unpredictable head first plummets and stomach churning jolts, but also
rapid and prolonged spinning, in either direction, as energy stored by keeping
the car upside down was judiciously released. However, the real rush was the
danger. Fear induced by the creaks and the rust lent an edge that a modern ride
could never have.
Dog and bone
I suggest that those who believe the “my dog swallowed my mobile phone” story
(Feedback, 14 April)
try dropping their mobile in a bucket of water, leave to
marinate for a few minutes, and then try calling it from another phone to see
whether or not it rings.
By the way, how do I know whether or not the light in my fridge goes out when
I close the door?
Correction
In our short news item “Sign up for Io”
(5 May, p 7),
we gave the wrong website address for the petition
to keep Galileo’s camera pointing at the Jovian moon Io next January.
It should have been http://fullspeed.to/io
It's not theft when lives are at stake
John Walker equates producing a drug patented by someone else with theft
(21 April, p 54).
This is too simplistic. One can only steal that which is owned
by somebody else, and ownership is a purely legal concept with shades of meaning
dependent on the local legal environment.
In India, drugs companies do not “own” patents on healthcare products,
because the law does not recognise them as property. If the drugs companies have
spent their money developing unpatentable technologies, that is their own
lookout.
Under almost any legal system, the sincere intention to save life is
mitigation or a defence against most charges, up to and including murder. Are we
seriously to believe that developing countries will abandon not only this
pragmatic principle but also their duty to the lives and security of their own
populations in order to enact legislation putting the profits of foreign
corporations first?
Would we expect the US and British governments to abandon their nuclear
programmes to honour patents held in India or China?
Hunger in paradise
I read with great interest your article on the possible adaptive value of
melanin in protecting against skin diseases
(28 April, p 7).
It is a pity that
the account is spoiled by an evolutionary just-so story tagged onto the end of
the article, in which the researcher speculates about the environmental
conditions in which dark and light skin would have evolved.
Briefly, there is no evidence that either our prehistoric ancestors living in
sub-Arctic conditions, or for that matter more recent Arctic foragers, found
themselves particularly short of food. They seem to have managed quite well.
Similarly, your writer’s account of “warm, damp tropics where food was
abundant” owes more to romantic travel imagery than to any ethnographic or
archaeological information. The last decade has in fact seen an active debate
about whether it is possible for hunter-gatherers to survive in tropical forest
without partnerships with farmers, precisely because of cyclical shortages of
nutrients in such environments.
The greater part of Africa’s land area, in any case, is not tropical forest,
and most of our information on modern human evolution comes from areas that
would have been woodland or grassland during the relevant time periods.