You expect me to what?! AS THE legions of gym bunnies and jogging enthusiasts who race out into the spring sunshine every year clearly demonstrate, running can be fun. More specifically, running triggers the release of brain chemicals called endocannabinoids that create a potent feeling of pleasure. As their name suggests, these endocannabinoids work in the same way as the active ingredient of marijuana.From an evolutionary standpoint this surge of endocannabinoids, and the “runner’s high” it creates, make sense. For ancient humans, remaining fit enough to run after game and away from predators and enemies was vital for survival. Yet whether other mammals are also driven to exercise by endocannabinoids has remained a mystery. Now a study led by David Raichlen of the University of Arizona has revealed that the runner’s high does exist in other species, but not in all.Dr Raichlen hypothesised that endocannabinoid-driven exercise highs would be found in those mammals that gain an evolutionary benefit from being fast on their feet: antelopes, horses and wolves, for example. However, he also...

THE phrase “indoor solar power” sounds like an oxymoron. But there is growing interest in the idea of using photoelectric cells to run gadgets as well as power grids—and doing so even when those gadgets are inside buildings. Much of the light these cells used would, of necessity, come from incandescent bulbs, fluorescent tubes and light-emitting diodes (LEDs) rather than through the window from the sun. But if the right sorts of cells were available this could be cheaper than constantly replacing the batteries that currently power electronic gizmos.On April 8th G24 Innovations, a firm based in Wales, announced that it may have come up with just such a cell. The latest version of its special, dye-based photoelectric devices has set a new record for the conversion of light from bulbs into electricity: an efficiency of 26%, compared with the 15% which previous ones can manage. That lifts dye-based cells to the point where they might be widely deployable for indoor power.Dye-based cells are similar to the silicon-based variety found on rooftops around the world in that both rely on a semiconductor to assist the conversion of luminous energy into the electrical sort. The difference is that in the case of silicon cells, this conversion happens directly. That means the frequency of light absorbed is constrained by the physical properties of silicon itself.In the case of dye-based...

Less is more IF YOU are a suspicious type you may be disturbed by the fact that, despite reassurances of the safety of the procedure, dentists and their technicians, when administering X-rays, usually step out of the room while the deed is done. Not only that, they often drape a lead-lined apron over your body to protect your vital organs. Well, all but one: your brain.A study by Elizabeth Claus, of Yale University, just published in Cancer, suggests your suspicions might be justified. Dr Claus thinks she has identified, in those who have had dental X-rays often, a significant rise in the admittedly small risk of developing a brain tumour.In rich countries, five men in every 200,000, and twice as many women, develop tumours called meningiomas that affect the membranes surrounding the brain. Meningiomas account for a third of primary brain tumours. Only about 2% of them are malignant, but non-malignant does not mean non-dangerous. Even a “benign” meningioma can kill. Around 30% do so within five years of diagnosis. Symptoms can include seizures and blindness, and...

ONCE upon a time the overstressed executive bellowing orders into a telephone, cancelling meetings, staying late at the office and dying of a heart attack was a stereotype of modernity. That was before the Whitehall studies, a series of investigations of British civil servants begun in the 1960s. These studies found that the truth is precisely the opposite. Those at the top of the pecking order actually have the least stressful and most healthy lives. Cardiac arrest—and, indeed, early death from any cause—is the prerogative of underlings.Such results have since been confirmed many times, both in human societies and in other primate species with strong social hierarchies. But whereas the pattern is well-understood, the biological mechanisms underlying it are not. A study just published in the Proceedings of the National Academy of Sciences, however, sheds some light on the matter.In it, a group of researchers led by Jenny Tung and Yoav Gilad at the University of Chicago looked at the effects of status on rhesus macaques. Experience has shown that these monkeys display the simian equivalent...

Home, sweet home ONLY one drug of every ten successfully tested in laboratory animals ends up working in people. One reason, of course, is that mice are not men. Another, though, might have to do with the fact that whereas human patients are afforded all manner of creature comforts, their animal proxies are not.Although medical science’s favourite critters relish temperatures of a little over 30°C, laboratories routinely keep them at five or ten degrees below that. This is not in order to torture the beasts but, rather, because when kept warm they are unmanageably aggressive. The downside is that they have to eat more than they otherwise would, in order to keep their bodies warm. That changes their physiology. And that in turn alters the way they metabolise drugs, with possibly confusing results.Joseph Garner, of Stanford University, thinks the answer is to keep the labs cool, but let mice cope with the low temperatures as they do in their natural habitat: not by eating more but by building nests. So far, though, no one has a clear idea of how much nesting material is needed to keep...

ONE stereotype of wisdom is a wizened Zen-master smiling benevolently at the antics of his pupils, while referring to them as little grasshoppers or some such affectation, safe in the knowledge that one day they, too, will have been set on the path that leads to wizened masterhood. But is it true that age brings wisdom? A study two years ago in North America, by Igor Grossmann of the University of Waterloo, in Canada, suggested that it is. In as much as it is possible to quantify wisdom, Dr Grossmann found that elderly Americans had more of it than youngsters. He has, however, now extended his investigation to Asia—the land of the wizened Zen-master—and, in particular, to Japan. There, he found, in contrast to the West, that the grasshoppers are their masters’ equals almost from the beginning.Dr Grossmann’s study, just published in Psychological Science, recruited 186 Japanese from various walks of life and compared them with 225 Americans. Participants were asked to read a series of pretend newspaper articles. Half described conflict between groups, such as a debate between residents of...

AMERICANS may no longer fret about being showered with nuclear-tipped ballistic missiles, but the idea that an atom bomb might enter their country in a shipping container or on the back of a lorry is still one that keeps the security services awake at night. They may sleep more easily, though, if an idea being developed by Michael Staib of the Florida Institute of Technology, in Melbourne, and his colleagues comes to fruition.Mr Staib is using naturally generated subatomic particles called muons to look inside places where such bombs, or the nuclear explosives needed to make them, may have been hidden by smugglers. At first sight this seems crazy. The muons in question drizzle down from the atmosphere at the rate of only one per square centimetre a minute. But, as Mr Staib told a meeting in Atlanta of the American Physical Society on April 2nd, this is enough for a practical muon scanner.Muons are like electrons, though heavier and unstable. They are produced when cosmic rays (fast-moving atomic nuclei from space) hit the atmosphere. The reason they might be useful for detecting nuclear explosives is that they are scattered more by heavy atomic nuclei, such as those of uranium and plutonium, than by lighter ones—even including relatively heavy elements such as lead. Clever electronics can tell the difference. Someone wanting to smuggle uranium or plutonium might shield...

THE biggest conceptual breakthrough in the war on cancer was the realisation by the 1980s that it is always a genetic disease. Sometimes the genetic flaw is inherited. Sometimes it is the result of exposure to an outside agent such as tobacco smoke or radioactivity. Sometimes it is plain bad luck; a miscopying of a piece of DNA during the normal process of cell division.Turning that breakthrough into medicine, though, is hard. No one has worked out how to repair DNA directly. It is, rather, a question of discovering the biochemical consequences of the genetic damage and trying to deal with those instead. But recently, another pattern has emerged. It is too early to call it a breakthrough as significant as the cancer-is-caused-by-broken-genes finding, but it might be.The pattern in question is that many of the genes whose breakage leads to cancer are themselves involved in a specific sort of genetic regulation, known as epigenetics. This switches genes on and off by plastering either their DNA or the proteins which support that DNA in chromosomes with clusters of atoms called methyl and acetyl groups. The nature...

Have you seen Cameron’s latest?  JAMES CAMERON knows how to make a splash. Literally. On March 25th the director of “The Terminator”, “Titanic” and “Avatar” plunged into the Challenger Deep of the Mariana Trench, 500km (300 miles) from Guam. When he reached the bottom, he sent a self-congratulatory tweet, and then tootled about for a couple of hours before taking Deepsea Challenger, his lime-green one-man submarine, back up the 11km to the surface.This venture certainly scores high in the jaw-dropping department. The only other people to plumb the Challenger Deep—as its name suggests, the most profound point in the ocean—were Jacques Piccard and Don Walsh, who did so in 1960, in a vessel called Trieste. The latest dive, however, was not very successful on the scientific front. It brought back no specimens.This was in sharp contrast to a less publicised mission, to the paltry depth of 2.5km, where the pressure is a mere 250 times that of the atmosphere (the Challenger Deep’s pressure is...

“IS SIN original?” That is the question addressed by Shaul Shalvi, a psychologist at the University of Amsterdam, in a paper just published in Psychological Science. Dr Shalvi and his colleagues, Ori Eldar and Yoella Bereby-Meyer of Ben-Gurion University in Israel, wanted to know if the impulse to cheat is something that grows or diminishes when the potential cheater has time for reflection on his actions. Is cheating, in other words, instinctive or calculating?Appropriately, the researchers’ apparatus for their experiment was that icon of sinful activity, the gambling die. They wanted to find out whether people were more likely to lie about the result of a die roll when asked that result immediately, or when given time to think.To carry out their experiment, Dr Shalvi, Dr Eldar and Dr Bereby-Meyer gave each of 76 volunteers a six-sided die and a cup. Participants were told that a number of them, chosen at random, would earn ten shekels (about $2.50) for each pip of the numeral they rolled on the die. They were then instructed to shake their cups, check the outcome of the rolled die and remember this roll. Next, they were asked to roll the die two more times, to satisfy themselves that it was not loaded, and, that done, to enter the result of the first roll on a computer terminal. Half of the participants were told to complete this procedure within...

I could have sworn I ordered this in blue ONE of the most interesting technological trends of the past few years has been the rise of additive manufacturing. This technique, which uses three-dimensional printing to make objects ranging from violins to pilotless aircraft, allows the construction of individual objects at the whim of the designer. Now, a small Californian company, the Gene Duplication Corporation, based in San Melito, proposes to push the technology to its limits. On Sunday it will announce plans to use 3D printing to make bespoke pets.GeneDupe, as the firm is known colloquially, has previously focused on the genetic engineering of animals. However Paolo Fril, the company’s boss, is keen to expand into manufacturing them from scratch. PrintaPet does just that.The idea of printing organs such as kidneys for transplant has been around for several years. It works by growing separate cultures of individual cell types, and then spraying them out, layer by layer, in combination with a binding agent called a hydrogel, to build up the correct shape.Printing an organ this way is...

IN THE winter of 2006 beekeepers in America noticed something odd—lots of their hives were dying for no obvious reason. As the months passed, reports of similar phenomena began coming in from their European counterparts. Mystified scientists coined the label “colony collapse disorder” (CCD) to describe what was happening. Since then, much brow-sweat has been expended trying to work out just what CCD really is.Dying bees are a problem, and not just for apiarists. Bees pollinate many of the world’s crops—a service estimated to be worth $15 billion a year in America alone. And there is no shortage of theories to explain the insects’ decline. Climate change, habitat destruction, a paralysing virus, fungal infection and even a plague of parasitic mites have all been proposed. But one of the leading ideas is that the bees are suffering from the effects of neonicotinoids, a class of commonly used pesticides, introduced in the 1990s, which are toxic to insects but much less so to mammals.Two papers published this week in Science lend weight to this idea. The first, from a group led by Penelope...

Journey’s end MADAGASCAR is renowned for its unusual animals, particularly its lemurs, a group of primates extinct elsewhere on the planet. Its human population, though, is equally unusual. The island was one of the last places on Earth to be settled, receiving its earliest migrants in the middle of the first millennium AD. Moreover, despite Madagascar’s proximity to Africa (400km, or 250 miles, at the closest point) those settlers have long been suspected of having arrived from the Malay Archipelago—modern Indonesia—more than 6,000km away.There are three reasons for this suspicion. First, it has been recognised for centuries that the Malagasy language, though distinct, borrows a lot of words from Javanese, Malay and the tongues of Borneo and Sulawesi. Second, the islanders’ culture includes artefacts ranging from boats with outriggers to xylophones, and crops such as bananas and rice, that are (or, rather, were then) characteristically Asian, not African. And third, genetic evidence has linked the modern Malagasy with people living in eastern Indonesia as well as farther off in...

FOUR weeks ago researchers at the OPERA collaboration, in Italy, discovered a glitch that may account for their startling finding last September that elusive particles called neutrinos move faster than light, in flagrant disregard of Albert Einstein’s theory of relativity. Now the first crosscheck from a rival experiment seems to vindicate the overwhelming majority of physicists who were convinced all along that an error must have crept in to OPERA’s analysis. On March 16th members of the ICARUS collaboration posted a paper on arXiv, an online repository, which reports that neutrinos they looked at are not travelling faster than light.Both OPERA and ICARUS study neutrinos sent from Europe’s main particle-physics laboratory, CERN. The particles are created in one of CERN’s accelerators, located just outside Geneva, and travel through the Earth’s crust to a laboratory beneath Gran Sasso, a mountainous massif in the Apennines. ICARUS’s measurements, all seven of them (not bad, given neutrinos’ unwillingness to interact with anything, including detectors), were taken at the end of last year, after the beam had been tweaked to improve the accuracy of the data.OPERA, too, tapped the modified beam, but reported in November that its un-Einsteinian result persisted. But then, on February 23rd, its researchers owned up to discovering what could be a source of...

DECK officers on American aircraft carriers use hand gestures to guide planes around their vessels. These signals are fast, efficient and perfect for a noisy environment. Unfortunately, they work only with people. They are utterly lost on robotic drones—and even if a drone is under the control of a remote pilot deep in the bowels of the ship, that pilot often has difficulty reading them. Since drones are becoming more and more important in modern warfare, this is a nuisance. Life would be easier for all if drones were smart enough to respond directly to a deck officer’s gesticulations.Making them that smart is the goal of Yale Song, a computer scientist at the Massachusetts Institute of Technology. He is not there yet but, as he reports in ACM Transactions on Interactive Intelligent Systems, he and his colleagues David Demirdjian and Randall Davis have developed a promising prototype.To try teaching drones the language of hand signals Mr Song and his colleagues made a series of videos in which various deck officers performed to camera a set of 24 commonly used gestures. They then fed these...

PASSWORDS are ubiquitous in computer security. All too often, they are also ineffective. A good password has to be both easy to remember and hard to guess, but in practice people seem to plump for the former over the latter. Names of wives, husbands and children are popular. Some take simplicity to extremes: one former deputy editor of The Economist used “z” for many years. And when hackers stole 32m passwords from a social-gaming website called RockYou, it emerged that 1.1% of the site’s users—365,000 people—had opted either for “123456” or for “12345”.That predictability lets security researchers (and hackers) create dictionaries which list common passwords, a boon to those seeking to break in. But although researchers know that passwords are insecure, working out just how insecure has been difficult. Many studies have only small samples to work on—a few thousand passwords at most. Hacked websites such as RockYou have provided longer lists, but there are ethical problems with using hacked information, and its availability is unpredictable.However, a paper to be presented at a security...

THOSE who worry about global warming have a simple answer to the problem. Simple in theory, that is: stop pumping carbon dioxide into the atmosphere. In practice that is rather hard to do. But there is another approach. Having put the stuff into the air, take it out.One proven way of doing this is photosynthesis. Measures to nurture and expand the world’s forests come high on the agenda of environmental proposals. But new forests take up a lot of land. How about a high-tech alternative: capturing the CO2 from air by artificial means and tucking it away in the Earth’s crust?Klaus Lackner, a physicist at Columbia University, started talking about this a decade ago. Peter Eisenberger, also of Columbia, and David Keith, until recently of the University of Calgary, in Canada, and now at Harvard, have taken up the idea as well. All three have formed companies aimed at doing it, with the help of some intrigued billionaires. Dr Lackner was patronised by the late Gary Comer, founder of Lands’ End, a large clothing company. Dr Eisenberger’s backer is Edgar Bronfman, whose fortune came from Seagram, a now defunct distiller...

PARTICLE physics is all very well for addressing trivial matters like “why are we here?” (see article). But some people question its practical usefulness. To answer such naysayers a group of physicists at Fermilab have just submitted a paper to Modern Physics Letters A in which they describe how they have built themselves a neutrino-powered telephone.Naturally, their neutrinophone is digital. A pulse of neutrinos (small, elusive subatomic particles with no electric charge) corresponds to the digit “1” while no pulse corresponds to “0”. The neutrinos themselves are created by smashing bunches of protons into a target made of graphite. They are detected roughly 1km away by researchers who, in their day jobs, work on a neutrino collaboration called MINERvA. By modulating the pulses of protons the group was able to send a message in binary that, when translated, read “neutrino”. Whether this will go down in history alongside Alexander Graham Bell’s first message, “Mr Watson, come here, I want to see you,” remains to be seen.The point, though, apart from sheer wackiness, is that neutrinos are not easily intercepted by collisions with other sorts of matter. If humanity wanted to broadcast its existence to intelligent life forms that might be out in the galaxy listening, a...

Time to start digging for victory MANY plans for reducing the world’s emissions of carbon dioxide—at least, those plans formulated by environmentalists who are not of the hair-shirt, back-to-the-caves persuasion—involve peppering the landscape with wind turbines and replacing petrol-guzzling vehicles with electric ones charged up using energy gathered from renewable resources. The hope is that the level of CO2 in the atmosphere can thus be kept below what is widely agreed to be the upper limit for a tolerable level of global warming, 450 parts per million.Wind turbines and electric vehicles, however, both rely on dysprosium and neodymium to make the magnets that are essential to their generators and motors. These two elements, part of a group called the rare-earth metals, have unusual configurations of electrons orbiting their nuclei, and thus unusually powerful magnetic properties. Finding substitutes would be hard. Motors or generators whose magnets were made of other materials would be heavier, less efficient or both.At the moment, that is not too much of a problem. Though a lot of...

HOT on the heels of results from Fermilab, in America, which reported last week on an esoteric phenomenon called charge-conjugation/parity (CP) violation involving equally esoteric subatomic particles known as D0-mesons, a second research group, the Daya Bay Collaboration of more than 40 institutions, mainly from China and America, has found a related result involving neutrinos. CP violation is an asymmetry between matter and antimatter and the experiment, based at a complex of nuclear reactors 50km (30 miles) north of Hong Kong, has settled a longstanding puzzle that bears on the question of whether neutrinos, too, experience it. That, in turn, is related to the deeper question of why the universe is made of matter rather than having originally had equal amounts of matter and antimatter. If such a primordial equity had prevailed, the two would have annihilated each other, leaving a universe filled only with energy.Strictly speaking, the Daya Bay experiment looked at antineutrinos rather than neutrinos. These particles are a by-product of nuclear fission, and the six reactors at Daya Bay and nearby Ling Ao turn...