Bone to pick
Chris Williams and Emma Nsugbe claim that their constructions are bone-like
(16 September, p 7).
Although they may look like bones, in one respect they are completely different.
The main feature of these architects’ constructions seems to be that they are
the product of a single relatively simple equation. The final shape of a bone,
on the other hand, is determined by individual bone-creating and bone-destroying
cells acting in accordance with the local state of strain, or damage, in the
bone. Damage is very different at different sites in the same bone, depending on
usage.
Perhaps even more striking is the way that, within the same bone, sites
separated by very small distances may undergo opposite actions. At one there
might be formation of bone, while nearby there is resorption. The cells may be
using the same algorithm to guide their local behaviour, but this algorithm will
only have inputs over a distance of a few tens of micrometres. There is no
overall guiding equation that can account for the architecture of a bone without
very local inputs.
It is of course interesting, and it happens often in biology, that completely
different routes can reach such similar end results.
Digital harassment
Your scenarios of daily life when the Internet becomes ubiquitous through
mobile devices fill me with dread
(21 October, p 33).
Your writers seem to assume that the quality of life will improve as Internet-connected devices
automatically profile and anticipate the needs and wants of Joe Public.
Current experience suggests this is way off beam. With existing technology,
many people already find the volume and culture of e-mailing has reached
disruptive and intrusive levels. I bet few New 杏吧原创 readers relish
the question “Did you get my e-mail?”, with its implication “Why haven’t you
replied already?” Instant delivery seems to require instant response. Imagine
what it will be like when people know that you can receive these horrors on the
move.
Automated profiling will bring its own set of nightmares. Somehow I have
already been classified as a middle-aged, stressed-out middle manager, and among
my 200 daily messages I find two or three targeting me as a likely consumer of
mail-order Viagra. Do I really want a future where my WAP-enabled PDA will start
vibrating every time I walk past a pharmacist? I enjoy information technology
enormously, but insist on regular breaks. I sincerely hope the “everything,
anywhere” scenario bombs.
Blinkered arrogance
Michael Snowden’s declaration that astronomy’s success in Western societies
is attributable to the Renaissance
(7 October, p 48)
does not stand up to close
scrutiny and smacks of cultural arrogance. Didn’t Egypt have some of the world’s
finest astronomers, millennia before the Renaissance? And wasn’t Chile largely
colonised by post-Renaissance Europeans?
It is true that astronomy, like many other aspects of science, does not
thrive in most developing countries, but surely poverty is at the root of the
matter. In a society where most people have to worry more about where their next
meal or medical costs are coming from, rather than pondering supernovae and
black holes, it is unrealistic to expect a sophisticated ethos of investigative
science to flourish.
Only someone in a wealthy nation could be blinkered enough to suggest that an
accident of distant European history is a more powerful force shaping today’s
“developed” societies than grinding poverty is for the “underdeveloped”.
Climate caution
I read Ehsan Masood’s interview with Paul Reiter with great interest
(23 September, p 41).
Being a seasoned climate change researcher, I am at present
serving as a lead author with the Intergovernmental Panel on Climate Change.
Reiter contends that there are serious arguments against there being a
significantly increased risk of malaria from global warming. His claim is
important as it challenges one of the “damage” cases of global warming which has
been all but undisputed publicly.
I believe that global warming is real. And I believe we must use our fossil
fuel resources carefully and limit emissions. But it would be helpful if the
right arguments were brought forward.
In that context I was disturbed by Masood’s comment: “But can you see why
some scientists go on about climate change and infectious disease? It’s taken a
long, hard fight to get the US to take global warming seriously, and scientists
don’t want to throw that away. Even the slightest contrarian messages can be
used by the oil and auto lobby to obstruct efforts to address global warming.”
It suggests that political correctness is more important than scientific
accuracy.
When dealing with the prospect of global warming, we should keep in mind that
climate science is not a value-neutral science. It may be OK for a politician to
emphasise the risks of global warming “if it’ll lead to greater public awareness
and investment in things like climate change research”. But scientists should
strive for scientific soundness. My impression is that Reiter gets that
straight.
Road blocks
Tam Dalyell is mistaken in thinking that devices which warn drivers of
traffic jams would reduce congestion and save fuel
(14 October, p 53).
Picture this: you’re driving to work when your device warns you of congestion
on your normal route. You decide to take an alternative route which is a couple
of miles longer, but might be less congested. Unfortunately, most other drivers
on the road heed the warning, and the alternative route soon becomes just as
congested as the direct route. The overall effect is increased congestion,
increased miles travelled and increased fuel use.
The only ways to reduce congestion and save fuel are to build more efficient
cars, provide fast, convenient, efficient public transport, and plan cities that
encourage walking, cycling and use of public transport rather than excessive
driving.
Divisive electron
The article “Double or quit”
(14 October, p 24)
seems to confuse the wave
function of an electron and the probability distribution associated with it.
According to the orthodox interpretation associated with Max Born, the founder
of quantum mechanics, the measurable attributes of the electron are linked to
the square of the modulus鈥攐r “size”鈥攐f the wave function. It is
surely this that Humphrey Maris must have measured.
At low temperature, liquid helium takes on the characteristic of a large
single particle. In terms of the Maris experiment, being able to change the
probability distribution associated with an electron says nothing about whether
an individual electron has been split. To find the physical significance of the
experiment one has to deal with all the wave functions to find the correct
probability distribution function.
Letter
Splitting a wave function is no new trick. Every interference pattern splits
a wave function into many (even an infinite number of) pieces, with the
probability of finding a particle is zero at each minimum in the interference
pattern. Only measurement allows us to know where the particle really is in this
pattern. I suggest that the “electrinos” are merely parts of a split wave
function, and that no measurement can be made of a partial charge. When a
measurement is made, the electron is found to be whole at a certain place and
the other parts of its wave function are immaterial.
Letter
Maris may, or may not, have hit upon something really big. How predictable
that some of the objections raised in Chown’s article appear to be based on the
tried and trusted reaction that “he can’t be right because he’s wrong”. New
theories have to be tested just like the old ones were, and this one’s going to
be fun to watch.
Pass the algae
If space vehicles can support an ecology of sorts
(14 October, p 34)
then it should be possible to develop self-sustaining closed ecosystems without having
to worry about the impact of microgravity on regular food crops. Astronauts on
trips to the planets wouldn’t need to carry several years’ worth of packed
lunches with them, space stations wouldn’t require constant restocking, and
sci-fi stories about “having to check the algae tanks” might become a reality.
Of course, two years of eating textured protein might prove a bit testing, but
“Earth foods” could be reserved for special occasions.
The future of humanity in space moves one little step forward!