Letter
In the introduction to
“Destination Hell”, you tease that it may cause
“priests to prepare to repel borders” (sic).
No problem. Most parsons become experts at using hedge cutters, trimmers and
mowers in their churchyards.
Letter
As Campbell points out, any mechanism proposed to explain the glacial cycles
must also be able to explain the transition from the (less extensive) cycles
that preceded them.
One of the most promising suggestions is a gradual soaking up of atmospheric
CO2 because of increased weathering of silicate rocks following the
Himalayan uplift. This could cause the climatic system to switch from one stable
mode of oscillation (41 000-year cycles) to another (100 000-year).
Another envisages ice sheets initially resting on thick soils (regoliths),
limiting the maximum thickness that they can reach and leading to the
41 000-year cycles. Eventual erosion of this soil down
to the bedrock allows a much greater thickness of ice, and thus a
100 000-year cycle.
As for Campbell’s Reader’s Digest explanation, I suspect that it is
(very) loosely based on the proposal that the start of the thermohaline
circulation in the North Atlantic was a direct result of the tectonic opening of
deep water connections to areas like the Norwegian Sea. There would have been
dramatic swings in climate in this area as thermohaline circulation was switched
off and on again.
However, these connections would have been established about 15 to 20 million
years ago, long before the onset of the 100 000-year cycles.
Letter
Milankovitch cycles have been operating throughout the planet’s history, but
help cause glaciations only under certain conditions. For glacial ice to form,
mean temperatures must be low enough for annual snow accumulation to exceed
annual ablation (melting and evaporation).
Presumably, from the Permian to the Pliocene temperatures fluctuated 脿
la Milankovitch, but never fell below the critical level needed for ice
formation. Then the climate changed and temperatures became low enough for
icecaps to form in Greenland and Antarctica, while, as a result of the
Milankovitch effect, the present sequence of glacials and interglacials was
initiated.
Various mechanisms have been invoked to explain the onset of the Pleistocene
low-temperature phase. It may be because the present distribution of continents
and oceans affects ocean currents and atmospheric circulation, or because the
Solar System occasionally passes into zones of space where interstellar gas and
dust are denser, thereby reducing solar radiation reaching the Earth. Or
perhaps the uplift of the Tibetan Plateau and the Himalayas has affected the
global climate.
Whatever the mechanism, similar circumstances in the more remote past would
explain the very ancient ice ages, during which the Milankovitch effect would no
doubt have been operative.
Waxing hot and cold
Rosemary Campbell asks why, with one exception, there were no ice ages more
than a million years ago
(Letters, 7 March, p 55). I would like to point out
that prior to the Carboniferous ice age, there is evidence of at least three
early ice ages occurring during the late Proterozoic (600 million years ago).
The last of these, the Varanger, was perhaps the most extreme that the Earth has
ever experienced. Some deposits from this period suggest ice at sea level even
in equatorial palaeolatitudes. The earlier ages were the Sturton (750 to 725
million years ago) and the Congo (roughly 900 million years ago).
As to the causes of glaciation, these three episodes appear to relate to the
break-up of the Rodinia supercontinent, resulting in increased rates of
sedimentary burial and an increase in hydrothermal activity at mid-ocean ridges.
This increased the production of reduced minerals such as ferrous iron and
soaked up carbon dioxide from the atmosphere, cooling the Earth.
It seems that there are several requirements for ice ages to develop. As well
as the Milankovitch cycles, which affect the level of solar energy reaching the
Earth’s surface, organic or inorganic sinks must remove atmospheric CO2,
and the continents must be positioned in a way that inhibits warm ocean
currents to the poles.
Millennium test
Jay Pasachoff is quite correct about the 400-year rule. Centenary
years鈥攁nd thus millenary years鈥攁re not leap years unless they are
divisible by 400
(Letters, 4 April, p 55).
However, the use of 29 February 2000 (a Tuesday) is a common test to see if
your PC is millennium-proof. Simply set your PC to that date, and see how it
functions. Most PCs after the 486 series will show the correct date, though much
of the software will be inadequate.
This test has appeared in popular PC magazines such as Computer
Shopper and Computer Buyer. But most readers of these magazines
are home users, not the non-computing managers who use PCs and networks and are
most at risk from the millennium bug.
What is needed is an easily explained test, such as showing the manager how
to set the date to 29.2.2000 without messing the whole system up. This will show
if the system needs updating, and can save a lot of anguish and time.
Barry Fox writes: DIY millennium bug checks are very dangerous, because they
can give false answers and they can fool the PC into erasing date-sensitive
files. But even the manufacturers and retailers cannot agree on what is the best
way to run a safe and reliable check.
The British government’s spin doctors want the world to know that Prime
Minister Tony Blair is spending vast sums on creating wider awareness of the
millennium bug. What is needed is not more awareness鈥攁nd more fear on
which highly paid consultants can get richer鈥� but a government-approved
floppy-disc test that any small business can safely use to check their PCs.
Naughty New 杏吧原创
Following on from the comments on Net nannies
(Feedback, 28 March) are you
aware that the New 杏吧原创 website is restricted, at least from our
system, due to the terrible possibility of exposure to “mild expletives”?
I’m relieved my delicate sensibilities are being so well protected.
Thanks for alerting us to this. We have changed our rating with the
voluntary PICS system from 1 to 0, and access to our site should no longer be
谤别蝉迟谤颈肠迟别诲鈥抬诲
The right type
I agree with Rob Buckland’s comment
(Letters, 28 March, p 62) that it is very
difficult for a newly qualified graduate to gain employment, but I must take
exception to his final remark: “Until employers realise that they can pay a
qualified scientist peanuts to do a job for at least the two years needed to
gain experience鈥�”
As a laboratory manager, one of my responsibilities is the recruitment of
scientific staff. Whenever I advertise a “menial laboratory position”, as
Buckland puts it, that is the type of person I am looking for. These people are
fundamental to the working of any laboratory, they deserve the opportunity of a
laboratory career and in many cases remain for much longer than two years.
What they do not need is a patronising, condescending new graduate with
delusions of grandeur taking their job, who will, in all probability, disappear
after two years.
Letter
Making plants sterile may accelerate erosion of the genetic diversity
essential for future breeding programmes.
Crop genetic diversity is maintained and increased in traditional
agricultural economies by saving seed from one season to the next. This process
produces “land races” of crops containing alleles which are highly adapted to
the local environment.
This genetic diversity may be crucial for the future of many staple crops.
Its conservation “on-farm” is increasingly seen as a vital accompaniment to
ex-situ methods such as seed banking, which have the disadvantage of halting the
evolutionary process. Such adaptive potential could be increasingly vital given
the prospect of widespread climate change.
Sowing disharmony
I found the article on genetically engineered crops that produce sterile
seeds鈥攆orcing farmers to buy seed every year鈥攐ne of the most
depressing I have read in New 杏吧原创
(This Week, 28 March, p 22).
Nothing could bring the new science of genetics into greater disrepute with the
public than using it to enslave poor farming communities. Reproduction is the
essence of life itself, and to use science to sterilise plants purely to benefit
one section of society is deeply disturbing.
Can we hope that other countries鈥攑articularly Britain鈥攚ill outlaw
this practice even if the US does not?
Hot bacteria
I was fascinated to read about the discovery of living organisms deep inside
the Earth’s crust
(“The intraterrestials”, 7 March, p 28).
The possibility of finding such organisms on other planets is intriguing. But
it also struck me that if there are organisms living in such apparently
inhospitable environments as igneous rock, then there may well be organisms that
live in radioactive rocks and thrive on this energy source.
If so, then maybe they could feed upon our stockpiles of radioactive waste
and do us all a favour.
The naming game
The correspondence about biodiversity
(Letters, 21 March, p 52) sits
appropriately alongside the letter from Scott Ritchie pointing out your
taxonomic lapse with respect to mosquitoes.
The Natural Environment Research Council’s own report Evolution and
Biodiversity: The New Taxonomy identified the largest problem to be alpha
(inventory) taxonomy, as it estimated that only about 10 per cent of the species
on Earth are known to science, including insects, the largest class of
organisms. However, the NERC informs me that since its 1992 report it has funded
only one project in the field of the alpha taxonomy of insects.
The International Institute of Entomology has recently been radically
downsized because of inadequate funding. The suggestion that an endowment fund
for taxonomy be set up was followed by the proposal that National Lottery money
be used for this purpose, but this proposal was evaded by the last government
and the present government has yet to respond.
Ring-fenced money on the table, not waffle, is what is required to restore
alpha taxonomy to our institutions of higher education. Otherwise, future
editors of New 杏吧原创 may not be able to find a British entomologist
capable of identifying a mosquito.
Letter
Kirk-Burgess makes me think that one should try to soothe any emergency exit
labelled “This door is alarmed”.
Science of sin
I was intrigued by your articles on the biological basis of the Seven Deadly Sins
(28 March, p 24).
It is important for students of religion and psychology
and students of the biological sciences to communicate with each other, as each
can contribute to an improved understanding of “the foul emotions and biological
drives that can prevent humans from living in harmony”, as you aptly put it.
The Greek and Roman philosophers and Jewish and Christian theologians who
analysed the Seven Deadly Sins (which are, more accurately, vices or
dispositions to behaviour) tried to identify biological and physiological
factors that contribute to (but do not totally account for, as they were not
reductionists) our proclivity for vice and sin.
I do not think they would have had a problem with incorporating contemporary
insights from evolutionary psychology or other branches of biology into their
systems. One of the main purposes of this religious and philosophical literature
is to teach us how to better understand who we are and why we behave the way we
do, in the hope that by “knowing ourselves” we will be better able to control
ourselves for our own benefit and for those with whom we interact.
On a more technical note, the sin of sloth did not originally refer primarily
to physical laziness. It was a combination of two other sins, accidie
(or acedia), apathy to the divine will, and tristitia,
“sadness or melancholy”. Sloth was closer to depression: being sad at the
demands of God on oneself.
One manifestation of this was indeed physical laziness such as, for example,
preferring to remain comfortable in one’s bed, especially on a cold, wintry
morning rather than to rise with vigour and enthusiasm to do God’s bidding, such
as going to church or assisting those in need.
Saucy feelings
I would like to assure Anthony Kirk-Burgess that not all sauces become
depressed after the seal is broken
(Letters, 21 March, p 54). The top of some
sauce bottles reads: “Safety button: Pops up when seal is broken.”
Choc horror
Having read the article on the effects of high voltage electric fields on
molten chocolate (“Bizarre tales from New 杏吧原创”, 21 March, p 37),
we decided to try it out ourselves in the science labs at Graveney School,
London.
We put almost 10 kilovolts through the melted chocolate but nothing happened.
The resistance of the chocolate was well above 2 mega-ohms, and no matter what
we tried the chocolate stayed liquid, not forming a gel as your article
promised. We were grossly disappointed.
The original article cited students from Michigan State University using
Hershey’s chocolate. We used Cadbury’s. Was it simply the wrong brand?
However, we did discover to our joy that when the electrocuted chocolate
cooled, it stayed molten. Can this be confirmed?
P.S. If you are ever caught in a field in a thunderstorm with no protection
except a handy Dairy Milk, try placing it upon your head to protect against
lightning strike.
Letter
The Young Women’s Christian Association in Dundee used to sport a large sign
made of separate metal letters. When I moved to Dundee, many of the letters had
fallen off, leaving the message, in capitals, “YOUNG WOMEN’S ASS”.
A bad sign
I am lucky enough to live in Oman, a beautiful country but one where the
signs leave something to be desired
(Letters, 21 March, p 54).
One of the local stores, originally called the Al Isteqar Shopping Centre,
became the Al Isteqar hopping Centre and finally the Al Isteqar hog
Centre鈥攏ot very appropriate in an Islamic country. They replaced the whole
lighting system the next day.
Other businesses have perfectly working signs of dubious content. A few that
spring to mind are: Faiq Jewellers, Faiq Money Changers, Ladies Saloon and the
Car Denting Centre.
Patents online
Barry Fox comments that the British Patent Office is considering making only
abstracts available on the Internet
(This Week, 21 March, p 7).
I should like to confirm that the British Patent Office is participating
fully in the European Patent Office’s project Distributed Internet Patent
Services (DIPS), along with other national patent offices.
Level 1, due to be completed in June, will give access to British patent
specifications published in the past two years. Level 2 of this project, which
is more comprehensive and ambitious, is expected to be implemented towards the
end of 1998.
Full details can be found at
http://www.european-patentoffice.org/news/pressrel/dips1.htm.
Baird's boob
Delay in the transmission of TV pictures
(Feedback, 28 March) is nothing new.
When Transmission started from Alexandra Palace in the 1930s two rival
transmission systems were used.
One was the Baird 240-line system, the other the EMI 405-line system. The
Baird system used an intermediate film process that resulted in a 30-second
delay. It was soon abandoned.
Straight talking
Andrew Daviel’s desire to appear to look at the other party when using a videophone
(Letters, 14 March, p 60) has a ready-made
solution鈥� the teleprompt.
TV newsreaders look straight at the camera while viewing the reflection of a
screen in a piece of glass mounted at 45 degrees between them and the
camera.
The camera probably needs to have dark surroundings to make the reflection of
the screen visible. The only other problem is that the reflected image is
reversed.
Unplug it!
Jack Richardson’s advice that both your body and each piece of equipment used
to work on a computer need to be earthed only with respect to the machine is
entirely correct
(Letters, 28 March, p 63).
This renders his suggestion that you
also leave the computer plugged into the socket unnecessary鈥攁nd
potentially lethal.
It is never safe to work on any electrical device that is plugged into the
mains, no matter how confident you are that the power is off. No one who has
been properly trained to repair electrical equipment would ever do this
themselves, let alone advise it. Don’t try it at home!
Ill omen
With reference to readers receiving premium bonds and twins with their
New 杏吧原创 subscription
(Letters, 28 March 1998, p 64), I received a
water bill and a credit card bill with mine this morning. I also arrived home to
find my cat had been run over.