Fleckfinger
Question: My fingernails are often flecked with white. I understand this is
caused by some sort of dietary deficiency or damage, creating air bubbles in the
growing nail. I have been told by numerous people that it is a lack of calcium,
sulphur and any number of vitamins. None of these have convinced me so far.
Why do the nails on my left hand have more flecks than my right (I鈥檓
right-handed)? And why not my toenails? Please someone, put me out of my
misery鈥攂efore I gnaw the phenomenon away completely!
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Answer: White discoloration of the fingernails is known as leuconychia. In
its 鈥渢rue鈥� form it affects the nail itself. There is also a false form which
affects the tissues that are found under the nail.
False leuconychia (which disappears on pressing the base of the nail) occurs
in severe albumin deficiency, when it appears as transverse bands of white
across the nails. True leuconychia can occasionally be caused by fungal
infection, but this rarely affects the whole of the nail. Broad bands of true
leuconychia have been attributed to deficiency of zinc or vitamin B6.
The commonest cause of true leuconychia, which appears as small white spots
of up to a few millimetres across, is percussive trauma. The best evidence of
this that I have seen was in a young man who had a shower of white spots on the
nail of only one finger, the one he used for drumming on the belly of his
guitar.
The questioner may be right-handed, but if he has more flecks on the nails of
his left hand, perhaps he uses that hand for drumming or some other traumatic
activity.
Jeff Aronson
Oxford
Answer: The main cause of this condition is minor trauma to the affected
area, involving the nail plate. It can arise from anything from an occupational
injury to overenthusiastic manicuring. Detergents, organic chemicals and oils
may produce similar results.
Leuconychia in the toenails is often seen in people who participate in
sporting activities, especially those sports which involve kicking.
Matt Newell
Kidderminster, Hereford and Worcester
Bottled up
Question: How do they get a fully grown pear inside a bottle of Poire William
liqueur?
Answer: The bottlers go into the pear groves and place empty bottles over the
pear buds. As they mature, they grow in the bottle. When nearly ripe, they are
picked and then the bottles are filled with the liqueur.
Steve Andrews
New York
Answer: I have successfully grown pears inside bottles a number of times.
Wait until the blossom has dropped off and the pear is at its earliest stage of
development. Place the bottle over this proto-pear, tie it securely in place,
and allow the fruit to mature inside the bottle as normal.
I find that it helps to blow air through the bottle (or to shade it) on
particularly hot days, and to remove any competing pears from the same branch.
This helps to stop the fruit rotting, and directs all the nutrients to the pear
growing inside the bottle. It can be cut from the branch when it is mature.
Refinements, such as peeling the pear inside the bottle, call for a good set
of appropriate tools and a steady hand.
Gavin Whittaker
Heriot, Midlothian
Answer: Some Japanese farmers grow melons inside cube-shaped containers. As
they grow they fill the container and end up as cubes. Although edible, these
melons lack flavour and are primarily ornamental.
Edward Edmondson
Barnwood, Gloucestershire
Answer: The idea of bottling fruit while it is still on the tree has been
taken up in California, where they grow aubergines in plastic moulds to make
them look like the faces of celebrities such as Elvis and Bill Clinton. Always
expect California to go one better.
Henrik Schmidt
Copenhagen, Denmark
Silkware
Question: What is the optimum life of a spider鈥檚 web? What happens to the web
after this period?
(continued)
Answer: The optimum life of a spider鈥檚 web is between one day and several
years. One-day webs are eaten daily by the spider to conserve proteins. Most
spiders use their webs for longer and renew them if they get damaged.
Examples of spiders with long-living webs are the house spider鈥攁s you
can witness if you crawl under your floorboards鈥攁nd the golden orb spider,
which make webs up to a metre square that may last for years.
Pacific islanders use the silk of the web from this latter spider to make
fishing lines, because it is so strong.
Ed Nieuwenhuys
Badhoevedorp, The Netherlands
This week鈥檚 questions
Free-fall falconry: According to the Audubon Society, the peregrine falcon
can dive at speeds of up to 270 kilometres per hour. However, I have also seen
publications that state a speed of anywhere between 320 and 450 km/h. Is there
not a terminal velocity that limits diving birds鈥� speed through the
atmosphere?
Jimmy Jones
Birmingham, Alabama
Nuke `em: It has been suggested that intercontinental ballistic missiles with
nuclear warheads could be used to destroy or deflect comets or asteroids that
are on a collision course with Earth.
For a comet with a velocity and size of Hale-Bopp, how much energy would it
take (in kilotons of TNT) and how far from Earth would the missile have to
intercept the intruder in order to respectively destroy or deflect it? And are
the missiles we now have fast and manoeuvrable enough?
Stein Jarving
Norway
Long-distance cone call: As a child in New Zealand, I was told that the
Krakatoa eruption in Indonesia was heard in Auckland. (At the time, the sound
was allegedly interpreted as the Russian Navy having a spot of artillery
practice.) By what mechanism could the sound of the eruption remain audible
after being transmitted for several thousand kilometres?
Michael Buckley
Zetland, New South Wales
Food scare: Why are you not supposed to refreeze meat which has defrosted? At
what stage of defrosting does it become unsafe to refreeze the meat?
John Provis
Asutsuare, Ghana
Beeline: My girlfriend tells me it impossible to explain how the bumblebee
flies. Apparently it defies the laws of physics. Is this true?
Torbj酶rn Solbakken
Norway