Letter
I want a remote control now. Pedestrian liberation will be achieved as soon as we can create instant diversions. The possibilities for dance performances are interesting, too 鈥� set, obviously, to a waltz remix of Kraftwerk’s Autobahn.
For the record
鈥� Apologies to Kristian Dixon, lead researcher on the team developing a robot that can reveal fingerprints on suspect packages (New 杏吧原创, 1 May, p 24). We erroneously called him Kristian Thomas. We also omitted to mention that his team included engineers at the University of Toronto as well as the University of Calgary. Apologies 鈥� Ed
Cone-o-rama
Reading Max Glaskin’s article on proposed robot traffic cones I had an immediate mental image of those cones being “liberated” (1 May, p 25). They would be attractive to, for example, amateur robotics enthusiasts, those wanting access to cheap GPS, anyone needing a powerful but cheap electric motor, and hackers who want to launch their own version of Battle of the Bots using modified traffic cones.
Traffic cones of today only have to contend with being wiped out occasionally by careless driving or kidnapping due to their unfortunate proximity to someone’s stag night (their souvenir value falls with growing sobriety, I can attest). Make them mobile and fill them with electronic goodies, and you’re virtually guaranteeing that every cone-lined road will become coneless overnight.
Could we see a return of the night watch, updated for the 21st century, huddled over brightly glowing braziers and equally bright laptop plasma screens monitoring their charges while they jostle for position along the roadside, occasionally sidestepping smartly as shadowy figures attempt to kidnap them under cover of darkness?
Letter
Will GPS enable those robotic traffic cones to determine precisely which statue’s head some drunken student has placed them on? Will they be able to dislodge themselves from said statue and return unaided to their intended position?
Security breach
I was fascinated by Feedback’s story (8 May) about artist Clayton Campbell wishing to create a montage from the identification photos of women who worked on building the atom bomb at Los Alamos during the second world war. This was nixed by a security officer at Los Alamos National Laboratory, who forbade the release of photos taken in 1945 鈥� incredibly enough on the basis that it could constitute a risk to national security.
At the risk of incurring the wrath of the Department of Energy, and possibly of being rounded up by Homeland Security and detained indefinitely, I shall tell you where you can find such a photo montage. Our article “Women of the Manhattan Project” can be found in the November/December 1993 issue of the magazine Technology Review. It is illustrated by a montage of identification badge photos of five women scientists from Los Alamos superimposed on a New Mexico landscape, as well as by photos of other women who worked on the Manhattan project.
Snake mimicry
Harry Greene cites examples of non-venomous snakes mimicking the colour, morphology and behaviour of venomous snakes 鈥� for example, gopher snakes pretending to be rattlesnakes (1 May, p 46).
In 1989 I was involved in an environmental study on Wetar Island in Indonesia, and was privileged to see a number of snake species, including pythons, tree snakes, racers, pit vipers and sea snakes. In terms of mimicry, however, the most surprising was the ular kepala dua (two-headed snake), Cylindrophis rufus.
This delightful little reptile is about 20 centimetres long, as thick as a pencil, and striped in orange and tan. It has distinctive markings on its head and tail, which resemble an inverted Greek omega (&Ogr;) with large black dots, and look like the markings on a cobra’s head. When disturbed, the snake hides its head under leaves or bark and rears up its tail in a cobra-like fashion 鈥� flattening the tail, swaying it back and forth and “striking” vigorously.
How this harmless snake (its mouth is so tiny that it would have trouble killing a tadpole) developed this behaviour is a real mystery, since cobras do not occur on Wetar. The islanders are terrified of it and believe it is highly venomous, the most dangerous part being its tail.
Hot on warming
Before demeaning science any further by making any more of his preposterous statements about global warming 鈥� “more dangerous than international terrorism”, “by the end of this century the only continent able to support us will be Antarctica” 鈥� may I beg David King to learn some basic facts of botany (17 January, p 13)?
Carbon dioxide is not the dreaded greenhouse gas that he cracks it up to be. It is in fact the most important airborne fertiliser in the world, and without it there would be no green plants at all. In fact, a doubling of the levels of this gas in the atmosphere would bring about a marked rise in plant production 鈥� good news for everyone, especially those malnourished millions who can’t afford chemical fertilisers or the spray booms to spread them.
Plants are very clever things, for their response to an increase in carbon dioxide in the air is to use it wisely, producing more roots than shoots to tap more mineral resources from the soil. That’s good news, and has the added benefit of burying lots more organic humus in the soil, just what soils need, especially when they are over-exploited and beginning to erode.
Please talk to your plants, and, as you do, rest assured that they in effect say “thank you” by recycling your waste carbon dioxide to make sugar and oxygen. Hooray for global warming!
Time after time
The article by Marcus Chown on the illusion of time gave some examples of ways to process information (1 May, p 34). However, all these examples are of behaviour that is the result of conscious thought.
There is some evidence that behaviour is actually the result of unconscious thought, and that conscious thought comes later. It seems you have already started to do something by the time your conscious mind makes the “decision” to do it. In this model, the conscious thought would presumably feed into a “register” and thence into unconscious thought 鈥� so that next time a decision is made unconsciously it is based in part on what you “decided” to do this time and on the outcome.
Bypassing conscious thought would have obvious evolutionary advantages for the frog trying to get the fly. But the frog probably still needs to think about what it is doing in order to enable it to adjust its strategies. A robot built to this model would always be in front, not necessarily by very much, but any improvement would be significant.
Letter
How naive and silly the arguments about time reversal in this article are. The fallacy is revealed in the very first example. A fly flies from a to b in time t. The frog observes and predicts the flight, strikes, is accurate or not, then survives or not.
This contains an absolute definition of the arrow of time, and an acknowledgment of its absolute importance for survival and selection. If the arrow were not a definite feature of the universe (whether the maths allows time and space to be interchangeable or not) then the reflex predict-and-strike reaction would not be universal.
Any other possibility along the lines suggested by this article and the underlying theories it reports would have led to frogs that could move their strike mechanics backwards in time to beat the competition. And that competition, in turn, would inevitably lead to infinite backward extensions until life were stifled at birth. The universe would be desolate and lifeless. And in addition, thermodynamics would not be the force it is.
Radio gaga
The low level of radio noise introduced across the spectrum by ultra-wideband (UWB), described in Danny O’Brien’s article may be too low for most users to notice (24 April, p 28). Radio astronomers, however, study the faintest possible radio radiation from space. Widespread use of UWB would be devastating for radio astronomy, and I sincerely hope that the idea founders on this unchangeable consequence.
Trade tribulation
As a development economist who reads your excellent magazine whenever I can prise it out of the hands of my physicist son, I applaud your coverage of the World Trade Organization’s ruling that US cotton subsidies are illegal (8 May, p 5 and p 8).
I would hesitate, however, to call it a revolution. A major multilateral institution, full of clever people, taking years to openly state the obvious is hardly a revolution 鈥� just a sign that justice and common sense do occasionally raise their head.
The US, should it notice the WTO’s ruling at all, will probably put more effort into reforming WTO rules than reforming its agricultural subsidy system. So revolution? Probably not. First step in a long process that might not work anyway? Probably yes. Will the children of African cotton growers remain hungry while the judgement and appeals go on? Definitely.
Letter
Dumping subsidised agricultural crops on third-world markets is not the only aspect of international trade rules with environmental dimensions. The World Bank’s zeal to induce governments of poor countries to encourage overproduction of exportable cash crops has caused the prices of these crops, on which these countries depend, to fall to their lowest level in decades.
Overproduction of cash crops often takes up the most fertile land that could otherwise be used for food production, and has driven displaced farmers to work more marginal areas, which exacerbates deforestation and desertification. Proposals led by Kenya and Tanzania to allow producing countries to reduce overproduction are also to be discussed soon in WTO negotiations.
Fat is a serious issue
Paul Campos’s comments claiming exaggeration and hysteria about the “obesity epidemic” seem a bit misplaced (1 May, p 20). He claims that studies are distorted by those who would benefit financially by offering “diet” plans. But these studies can also be distorted by the huge pharmaceutical industry which sees financial gains in new drugs to ease the symptoms of obesity.
His use of mortality as a yardstick in measuring the health effect of increased weight on the human body is also questionable. Death should not be the only measure of the effect of being overweight. The societal effects and the burden on the healthcare system must also be taken into consideration.