Scans still safe
Your article on ultrasound scans
(This Week, 12 June, p 23) caused a lot of
alarm among pregnant women. Clearly if there is irrefutable evidence that
ultrasound has caused harm, this is a matter of great public importance.
What concerns me, however, is that the research you published may not apply
to humans. It is also probably flawed. The study was on a very small number of
mice, and it seems that control experiments were not carried out. The process of
immobilising the mouse, shaving its abdomen and applying a large ultrasound
probe for 15 minutes is likely to cause damage not only to the bowel, but to
other organs as well. The damage could also have been due to bubbles in the
mouse’s intestines. Human fetal intestines do not contain bubbles.
Hundreds of experiments have been published on the effects of ultrasound on
mice and the effects reported here are no different to what one might have
expected. Scientific evaluation of these studies has always indicated that
extrapolation to human fetuses is difficult, and there is a consensus of opinion
from the major international bodies regulating ultrasound diagnosis in pregnancy
that it is safe.
Routinely used
In his article about genetically modified crops that are resistant to
broad-spectrum herbicides, Andy Coghlan states incorrectly that: “No herbicides
of this strength have been used in Britain before”
(This Week, 10 July, p 18).
Glyphosate (Roundup) has to my knowledge been cleared for use in this country
for the past twenty years and glufosinate-ammonium for about seven years.
Roundup is used as a pre-harvest desiccant in several crops, including
oilseed rape and cereals, as well as for the treatment of grass swards prior to
silage-making or conserving for hay, for the control of aquatic weeds and for
the protection of fruit trees, among other things. Additionally it is sold in
the amateur sector as Tumbleweed, where it is used liberally by all and
sundry.
Glufosinate-ammonium is similarly cleared for use to protect many vegetables
and crops. It is also sold in the amateur sector.
I have been selling these products in very large volumes, as has the rest of
the distributive trade here and everywhere else in the world, for more than
twenty years.
Andy Coghlan writes: I regret any confusion to readers caused by
the error. But the main point still stands: that if crops tolerant to
broad-spectrum herbicides are accepted and widely grown in
Britain, we can expect farmers to apply far larger quantities of these chemicals
than at present. It is this potential for much wider use of broad-spectrum
agents that worries many environmental organisations.
Creepy corpse
I was interested to read your tale of the “undead” rattlesnakes which are
still capable of striking and wounding unwary people
(This Week, 3 July, p 23).
While on vacation at my rural childhood home a few years ago, my 12-year-old son
Nate and his uncles killed and decapitated a small rattlesnake on the Teton
river in Idaho. Anxious to present this trophy to his squeamish mother, my son
dutifully carried the squirming snake in a cloth fishing creel throughout the
afternoon fishing trip. My wife was suitably horrified when it was dumped onto
the farm’s kitchen table that evening.
As it was late evening by this time, we decided to refrigerate the carcass
overnight before skinning it. After it spent the night in a plastic trash bag in
the vegetable crisper drawer of the refrigerator, we removed its skin and rattle
and threw the still-writhing carcass into the back yard for whatever scavengers
might want it as a snack. We were a bit surprised later to see the carcass raise
its headless (and skinless) trunk and begin moving through the grass.
The snake carcass continued its relatively normal movements in the yard for
three days, and was still moving when we packed up and returned home. Apparently
a snake retains enough of its nervous system to display normal locomotion (and
defensive striking stances) for several days after decapitation. Obviously there
is no such thing as a “completely dead” snake for quite some time “post mortem”
and a supposedly dead rattler with head attached should be treated with extreme
caution.
Better barbecues
Eco-friendly non-flaring gel for lighting barbecues
(This Week, 26 June, p 5)
seems to be another complicated answer to a more easily solved problem. I, and
many other South Africans, keep a few lumps of charcoal in an old jam jar filled
with methylated spirits. After a while the charcoal absorbs enough spirit to
make a most effective nonpolluting firelighter.
Future shock
Most digital watches I have bought for about 拢25 have calendars that
will work between 1990 and 2039, which is more than adequate for the expected
life of the watch. So I was quite impressed last year when I bought a pocket
travel clock for 拢15 whose calendar works from 1901 to 2099. It will
definitely see me out.
Last week I bought a mini-databank, the MiniPad, from Bluebird Toys. It was
originally priced at 拢7.50, but I paid a “clearance” price of 拢1.87.
Not only does this brightly coloured “toy” allow the input of any date between 1
and 9999, but it also correctly adjusts for leap years in years ending in “00”
over this range, following the Gregorian calendar. That is, it adds a 29
February to years ending in “00” only if they are divisible by 400.
When I tried it out, this device proudly indicated that 7200 will be a leap
year and 7300 will not. For just 拢1.87, I have a device that will store 20
telephone numbers, do floating-point arithmetic and keep track of the Gregorian
calendar for the next 8000 years.
I think I will have it placed in my coffin, so that archaeologists of the
distant future will have a convenient way of knowing the date when they find my
remains.
Signals at sea
As a true naval Briton, I suggest that the inventor of radio was actually
Captain Henry Jackson of the Royal Navy
(Letters, 10 July, p 56). He sent
signals by radio from ship to ship in 1896 and only later became a friend of
Guglielmo Marconi.
Where it hurts
Jeff Oliver should widen his research on the stinging sensation caused by burping Coke
(Feedback, 26 June).
It’s not only Coke that has the effect he has
noted, nor solely on nasal mucous membranes. No one who has ever had the idea
that those lovely little bubbles in a mouthful of Champagne might have a
stimulating effect if applied topically during an amatory experience will ever
try the experiment twice. This is true regardless of gender.
I am nevertheless interested in Oliver’s suggestion that it may be a warning
mechanism telling you to come up for air.
Correction:
In Ralph Estling’s letter about the article “Cosmic lottery”
(3 July, p 56),
the article’s author was given as Robert Matthews. It was in fact Jeff Hecht.
Tricks of the trade
Academic fraud should come as no surprise to anyone
(“Your mission is鈥�”, 3 July, p 38).
We have all seen examples, often even before we make
the decision to aim for a scientific career. How many New 杏吧原创
readers altered their experimental results in school to avoid losing marks when
an experiment failed?
One of the reasons why I turned my back on biochemistry was an incident that
happened at university. The experimental setup was quite simple. To study the
kinetics of an enzyme-driven reaction we looked at the rate at which the enzyme
bleached a blue dye. The experiment failed because the dye solution was too
strong. I diluted it and it worked perfectly, so that’s how I wrote it up. All
of the rest of the year obtained perfect results鈥攄espite using a solution
too opaque to register on the spectrophotometer. I asked the previous year’s
students how the experiment worked for them. They had also handed in perfect
results despite failing to get a single reading.
The technician who made the solution hadn’t noticed any problems. It looked
just like the ones she had made up in the previous five years.
Thankfully I now work in a more honest field. Advertising.
Letter
I am a PhD student at one of Britain’s top universities. A couple of months
ago a fellow graduate student was summoned to his supervisor’s office to discuss
his experiments and was told that “you have been having negative results for too
long”. When the student asked what he was expected to do about it, the
supervisor looked at him in silence as if the answer was obvious.
I am astonished that as few as 18 per cent of scientists know of students
plagiarising data. I suspect the real figure is much higher. The question should
be: who is causing students to feel that they need to plagiarise data?
Young people are leaving research in droves. When I finish my PhD I will be
one of them. I see too many academics I have no desire to emulate.
Lies, lies, lies
Another disadvantage of the polygraph
(Opinion, 19 June, p 52) is that it can
lead to complacency. For example, the CIA, which has used the polygraph
routinely for many years, has placed far too much trust in it.
More than a hundred people had access to the identities of all the American
agents in the Soviet Union. One of those hundred was, of course, Aldrich Ames,
who passed a polygraph test after he became a Soviet agent.