Joel Lopes Da Silva on the Web!

People come into the world ready to count its wonders

THE baby is just one day old and has not yet left hospital. She is quiet but alert. Twenty centimetres from her face researchers have placed a white card with two black spots on it. She stares at it intently. A researcher removes the card and replaces it by another, this time with the spots differently spaced. As the cards alternate, her gaze starts to wander—until a third, with three black spots, is presented. Her gaze returns: she looks at it for twice as long as she did at the previous card. Can she tell that the number two is different from three, just 24 hours after coming into the world?

Or do newborns simply prefer more to fewer? The same experiment, but with three spots preceding two, shows the same revival of interest when the number of spots changes. Perhaps it is just the newness? When slightly older babies were shown cards with pictures of household objects instead of dots (a comb, a key, an orange and so on), changing the number of items had an effect separate from changing the items themselves. Could it be the pattern that two things make, as opposed to three? No again. Babies paid more attention to rectangles moving randomly on a screen when their number changed from two to three, or vice versa. The effect even crosses between senses. Babies who were repeatedly shown two spots perked up more when they then heard three drumbeats than when they heard just two; likewise when the researchers started with drumbeats and moved to spots. ...

Arguments over what counts as a number

Correction to this article

EVERY now and then mathematics has been convulsed by a row, not over where numbers come from—but over what should be allowed to count as one. Two millennia ago, inspired by such discoveries as the relationship between musical pitch and the lengths of vibrating strings (double the length of the string and the note falls by an octave), the followers of Pythagoras decided that all of Nature must be expressible as ratios of whole numbers. Their discovery that one very simple geometric ratio—that of the length of a square’s diagonal to the length of its side—could not was, according to legend, so shocking that it was kept a secret on pain of death. ...

A new vehicle arrives to break an old record

THE early days of motoring produced a three-horseless race, as it were. To start with, electric and steam-powered vehicles outsold those with newfangled internal-combustion engines. However, the invention of the starter motor and the longer range of the petrol- and diesel-powered models eventually gave those vehicles the edge, and electric and steam-powered cars drifted into obscurity. Now, with the benefit of advanced electronics and lightweight batteries, electric cars are staging a comeback. Could steam cars do the same?

This week, a group of engineers known as the British Steam Car Challenge have been completing the initial test runs of a 7.7-metre (25-foot) steam car which they hope will travel at more than 274kph (170mph). Early next year they will ship it to America for high-speed testing. Eventually, they hope to beat the land-speed record for steam cars. ...

To attract a woman by wearing scent, a man must first attract himself

THE very word “perfume” has feminine overtones to many male ears. Men can be sold “deodorant” and possibly “aftershave”, but the idea of all those dinky little bottles with their fussy paraphernalia is too much for the sensitive male ego. Yet no industry can afford to neglect half its potential market, and perfume-makers are ever keen to crack the shell of male reticence. Now they may know how to do so.

Craig Roberts of the University of Liverpool and his colleagues—working with a team from Unilever’s research laboratory at nearby Port Sunlight—have been investigating the problem. They already knew that appropriate scents can improve the mood of those who wear them. What they discovered, though, as they will describe in a forthcoming edition of the International Journal of Cosmetic Science, is that when a man changes his natural body odour it can alter his self-confidence to such an extent that it also changes how attractive women find him. ...

More signs of universal dark energy

IT IS hardly surprising that something called dark energy is hard to study. It is important, though. If it exists at all, it makes up about three-quarters of the stuff in the universe. And if it does not exist, then existing theories of physics will have to be scrapped.

The latest evidence that dark energy really does exist was produced on December 16th by Alexey Vikhlinin, of the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, and his colleagues. They used an orbiting X-ray telescope called Chandra to study the way that clusters of galaxies grow. They discovered that this growth is stifled in exactly the way that dark-energy theory predicts. ...

Pain is enhanced if deliberately inflicted

IF SOMEONE accidentally steps on your toe, it hurts. But does it hurt more if you think he did it deliberately? That, in essence, is the question Kurt Gray and Daniel Wegner of Harvard University asked in a study they have just published in Psychological Science. And their answer is that it probably does.

Dr Gray and Dr Wegner did not actually tread on people’s toes as part of their experiments. But they did arrange for them to receive electric shocks. Altogether, they induced a group of 43 students to participate with offers of academic credits or, failing that, cold cash. ...

A rare antelope changes its sex strategy as it gets older

THOUGH youth is supposedly the time of life to take foolish risks, it in fact makes more sense to save such things for old age. Young animals should be cautious, to stay alive long enough to reproduce. Old ones should be willing to gamble with their lives since there is not much time left anyway. Although this theory of age and risk makes sense (the risks young animals take are mostly connected with attracting and retaining mates, and are thus worthwhile), proof has been elusive. It requires following a population over the course of several generations. But a study of appropriate proportions has now been done, and it suggests that in one species at least, old age does indeed increase risk-taking.

The study in question was of Nile lechwe, an endangered antelope. The animals were held in an enclosure of 36 hectares (90 acres) at the San Diego Zoo’s Wild Animal Park near Escondido. The site contains ten other species of African ungulate as well as a variety of African birds. The project has resulted in the birth of 176 lechwe calves over the course of 38 years and, since this has happened under the watchful gaze of the zoo’s researchers, a lot of details about these young animals and their mothers have been recorded. ...

Taking fertility drugs may increase women’s risk of cancer

DRUGS designed to coax ovaries to produce at least the requisite one egg a month have been a cause of concern for some time. At first worries centred on the possibility of increased risk of ovarian cancer. Then came concern about breast cancer. But studies have produced mixed results, leaving women and doctors in a bit of a quandary.

Part of the problem is that cancer can take decades to appear, so only a lengthy follow-up will expose an increase in its incidence. It is also well known that women who never give birth are at greater risk of various cancers; studies had trouble untangling that effect from any connection to fertility drugs. ...

Vaccines may help defeat both a scourge of the poor and a rich-world affliction

FOR much of the 19th century, Bagamoyo was a dreadful place, at the heart of the east African slave trade. The very name of the Tanzanian port means “lay down your heart” in Swahili. But that tragic association may be supplanted by a happier one, thanks to an important new study done in the city that shows how to tackle a killer that has long outlasted Bagamoyo’s trade in human beings.

Most malaria experts have pinned their hopes of tackling that disease with new drugs, such as artemisinin-combination therapies, and the use of bed-nets impregnated with long-lasting insecticides. However, the Bagamoyo study suggests that vaccination deserves a serious look. By coincidence, an unrelated report suggests that vaccines may also have an important part to play in tackling Alzheimer’s disease, which tends to afflict longer-lived people in richer countries. ...

Cars are getting better at avoiding collisions. Before long they may be communicating with each other to make roads safer

VOLVO’S new XC60 sport-utility vehicle comes, as you might expect of the safety-conscious Swedish carmaker, with a number of features designed to look after its occupants in the event of a collision. It has airbags, rollover and side-impact protection and so forth. But it is also fitted with mechanisms to help avoid a crash in the first place, including an automated braking system. As more cars acquire features that can assist a driver in a dangerous situation, or even take control, the rules of the road may need rethinking.

The Volvo system, called City Safety, operates at up to 30kph (19mph). This speed range was chosen because it is when most collisions take place, especially rear-end shunts in slow-moving traffic. City Safety uses a laser sensor fitted behind the windscreen to scan the road ahead, calculating relative speeds and distances. It applies the brakes if a collision cannot be avoided. (The system switches off at very low speeds, so that drivers can park close to other vehicles.) ...