Category Archives: Science and Technology

What makes good music?

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HIT songs are big business, so there is an incentive for composers to try to tease out those ingredients that might increase their chances of success. This, however, is hard. Songs are complex mixtures of features. How to analyse them is not obvious and is made more difficult still by the fact that what is popular changes over time. But Natalia Komarova, a mathematician at the University of California, Irvine, thinks she has cracked the problem. As she writes in Royal Society Open Science this week, her computer analysis suggests that the songs currently preferred by consumers are danceable, party-like numbers. Unfortunately, those actually writing songs prefer something else.

Dr Komarova and her colleagues collected information on music released in Britain between 1985 and 2015. They looked in public repositories of music “metadata” that are used by music lovers and are often tapped into by academics. They compared what they found in these repositories with what had made it into the charts.

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Metadata are information about the nature of a song that can give listeners an idea of what that song is like before they hear it. The repositories presented Dr Komarova and her team with more than 500,000 songs that had been tagged by algorithms which had been trained to detect numerous musical features. The tags included a dozen binary variables (dark or bright timbre; can or cannot be danced to; vocal or instrumental; sung by a man or a woman; and so on). The team fed all of this information into a computer and compared the features of songs that had made it into the charts (roughly 4% of those in the repositories) with those of songs that had not.

Overall, the team’s results suggested that songs tagged as happy and bright have become rarer during the past 30 years; the opposites have therefore appeared with greater frequency. That was not, however, reflected in what made it into the charts. Chart successes were happier and brighter (though also less relaxed), than the average songs released during the same year. Chart toppers were also more likely than average songs to have been performed by women. All this is important information for executives of music companies.

Dr Komarova used these results to train her computer to try to predict whether a randomly presented song was likely to have been a hit in a given year. The machine correctly predicted success 75% of the time, compared with the 4% rate that guessing success at random from the music database would yield—something else music executives might pay attention to.

Content is not everything. As might be expected, circumstances—particularly any fame already attaching to a recording artist or artists—had an effect, too. But not a huge one. Adding in information about who was performing a song increased the accuracy of prediction to 85%. That suggests that musical fame is actually attached to talent, rather than to hype. And this, perhaps, is a third lesson for an industry that some believe is not wedded to talent enough.

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Source: https://www.economist.com/news/science-and-technology/21742686-composers-and-listeners-disagree-what-makes-good-music?fsrc=rss%7Csct

Colombia’s national survey of its biodiversity is ambitious

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“BLOODY plants! Always in the way.” That is not the sort of expostulation expected of a researcher from the Royal Botanic Gardens, Kew. But Lee Davies is not a botanist, he is a mycologist—an expert in fungi—who, at home in London, helps curate Kew’s fungarium. And, although history and convenience mean the study of fungi is often lumped together with that of plants, Dr Davies is keen to point out that mushrooms and their kin have nothing in common with the vegetable kingdom beyond their sedentary way of life.

His sentiment was particularly understandable on this occasion. Being ankle deep in mud, on a narrow trail traversing a precipitous hillside that was sloping down who-knew-how-far-or-where, and then trying to collect a specimen hidden just out of reach behind a tangle of greenery, would fray anyone’s nerves. But the specimen was duly acquired, popped in a plastic bag, labelled and carried back to base camp for processing and identification.

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Dr Davies and his compadres were in Colombia, in the Serranía de las Quinchas, an area of cloud- and rain-forest in the foothills of the Cordillera Oriental that was, until a peace deal signed in 2016, part of the sphere of influence of the FARC, a group of rebels fighting to overthrow the government. The FARC did not encourage visitors. As a consequence areas they controlled, which amounted at their height to about 40% of the country, are often more or less pristine from an ecological point of view. They are also, as far as flora, fauna and fungi are concerned, poorly catalogued.

That, though, is changing as a result of Colombia BIO, an attempt by the government to take advantage of the FARC’s departure and to explore what is living in the recently vacated habitats. So far, since 2016, the project has sponsored 13 expeditions staffed by botanists, mycologists, entomologists, ornithologists, herpetologists and many other sorts of biologists. The figure should rise to 20 by the end of the year.

The hope is to run 100 more expeditions over the next decade, by which time Colombia’s forests, swamps and mountains will have been comprehensively sampled and recorded. Dr Davies and his colleagues were there because, to bolster Colombia’s still-small regular army of pertinent experts, the country’s government has recruited several groups of foreign mercenaries.

Hi ho! Hi ho! It’s off to work we go

Colombia BIO is the brainchild of the country’s president, Juan Manuel Santos. Just as, in the 19th century, many countries set up geological surveys to assess their mineral assets, so Mr Santos aspires to survey, in a comprehensive and systematic way, Colombia’s biological assets.

Measured by number of species, these are enormous. Its tropical location and topographical variety mean Colombia’s biodiversity is second only to Brazil’s. How valuable such assets are, though, is a different question. Some habitats are clearly crucial. In particular, there are worries deforestation will upset the hydrologic cycle in certain places, threatening water supplies and hydroelectric power generation. Also, trees have value as timber. But that is not quite what Mr Santos means when he speaks of turning Colombia into a “bioeconomy”. The government’s aspiration is that biodiversity itself might be harnessed as an economic resource, and that this might contribute as much as 2½% of Colombia’s GDP by 2030.

Exactly what constitutes part of a bioeconomy is a bit hazy. At the moment, those involved tend to throw into the pot anything that might vaguely count: ecotourism; wild fruits and nuts that can command a premium price; cosmetics made from forest products that appeal to the virtue-signalling middle classes. But the long-term aspiration is more ambitious. It is that some of the organisms to which Colombia plays host might act as feedstock for a future in which genes and metabolic pathways can be monetised in the ways that gold and other minerals once were. And for them to be so monetised, they must first be catalogued and analysed.

Making that happen is the remit of Alejandro Olaya Dávila, the director of Colciencias, Colombia’s government science agency. This is Colombia BIO’s parent body. The samples collected are destined for a national repository, whence they will be distributed for study. There are also, according to Dr Dávila, plans for a national research centre for biotechnology and a government-backed venture-capital fund that will finance start-ups in the field—an endeavour helped by the recent repeal of a law specifically preventing academics at state universities from doing this.

The repository is at the Alexander von Humboldt Biological Resources Research Institute, in Bogotá. Brigitte Luis Guillermo Baptiste, the Humboldt’s director and herself an ecologist, says she was sceptical about the likelihood of a grandiose project like Colombia BIO succeeding. She changed her mind, though, when initial expeditions proved successful in discovering new species and rediscovering old ones thought extinct. Her doubts now centre on whether the government can act fast enough to protect those areas vacated by the FARC. She cites an example of a stretch of river, tributary to the Amazon, that was almost completely denuded of its fish a mere 15 days after the guerrillas left.

Silvia Restrepo, a mycologist who is vice-president of research at the University of the Andes, one of Colombia’s leading academic institutions, points to other obstacles. Perhaps the most curious is that ecological researchers—even Colombian nationals—not only have to obtain permits to collect specimens but also have to pay a levy of 15,000 pesos (about $5) on every specimen taken. And that means every specimen. Collect 100 mosquitoes, for example, and you pay 100 times. This makes collecting an expensive business.

It is also hard to export specimens for study abroad. That would matter less if Colombia’s own facilities for things like genetic sequencing were up to snuff. But they are not. Yet such sequencing is a vital starting-point for any serious investigation of the economic potential of a species.

Another complaint by researchers involved in Colombia BIO is money. In theory there is plenty. By law, 10% of the royalties raised by the government on extracted oil and gas are supposed to be set aside for scientific research. Last year, that amounted to $390m. Although the royalties are collected centrally, the cash is then disbursed to the administrations of the country’s 32 provinces. Colombia BIO’s central budget is tiny—about $4m a year. The bulk of the money for the expeditions comes from the provinces in which those expeditions are mounted. It is the governors of these provinces, therefore, who decide what science gets funded and, indeed, what the definition of “science” is. Speculative surveys of the country’s biodiversity are not always top of the list.

Nor are they top of the list for many other people. The newly liberated land is a target for squatters, whose modus operandi is to clear the trees for profit and then run cattle over the resulting pasture. Local politicians often turn a blind eye to such activity, especially if bribed to do so. And the average Colombian, whether urban-dweller or rural smallholder, is less concerned with rarefied matters like biodiversity and its possible role in a speculative biotechnological future, than with the immediate business of making ends meet.

And speculative that future is. How big a role biotechnology will play in the economy of the 21st-century world is hard to predict. It could be huge, with products now unimaginable becoming available as a result of new techniques of gene editing and the creation of synthetic genomes. Or it could, as now, be an important factor in agriculture and medicine but of little wider resonance. At least at the moment, successful biotechnologies are more often derived from microbes and fungi than from the plants and animals that attract the attention of most conservationists. That argues for recruiting more Restrepos and Davieses to the effort. Moreover, if Colombia really is to benefit from its genetic patrimony, it will need to build up its scientific base and get rid of red tape that stands in the way of research. In the end, therefore, Colombia BIO will survive or fall depending on its support from the top.

Will the end, will the means

Whether the president’s aspirations are shared by other national politicians will soon become clear. On May 27th, Mr Santos having served as president for the maximum period permitted by law, Colombians go to the polls to elect a replacement. After a possible second round in June, the winner will take office in August.

Amid Colombia’s many problems, not least making the peace settlement with the FARC stick, biodiversity would be easy to forget about. But it is not forgotten entirely. One candidate, Iván Duque, talks of an “orange economy” of knowledge-based production, which might bode well for aspiring biotechnologists. A second, Gustavo Petro, is a former guerrilla who says he is keen on renewable ways of creating wealth. And a third, Sergio Fajardo, a maths professor who was once mayor of Medellín, also seems interested.

Whether such inclinations would translate into action in office remains to be seen. But, at the very least, Colombia BIO offers an opportunity to clarify which parts of the country’s wild areas most deserve protection at a moment when the offer of protection is still meaningful. And, since no one actually knows how the biotechnological future will turn out, just possibly the surveys it is sponsoring will reveal riches that make the gold rushes of the 19th century look like chump change.

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Source: https://www.economist.com/news/science-and-technology/21742685-will-it-survive-forthcoming-presidential-election-colombias-national?fsrc=rss%7Csct

Arctic ice brings an understanding of ancient Europe’s economy

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GREENLAND’S icy mountains are not an obvious place to search for an archive of economic history, but a study just published in the Proceedings of the National Academy of Sciences shows that they provide one. Joseph McConnell of the Desert Research Institute, in Reno, Nevada, and his colleagues have tracked economic activity in Europe and the Mediterranean over the centuries by measuring variations in the amount of lead in a core of Greenlandic ice. Lead is a good proxy for economic activity because it is a by-product of silvermaking (lead and silver often occur in the same ore, known as galena), and therefore of the money supply. Extracting silver from galena involves boiling off the lead. Winds from Europe carried to Greenland enough lead pollution from this process for it to be preserved in the layers of snow that, compacted, form the island’s ice cap.

Although the lead concentration in the core that Dr McConnell looked at shows many peaks and troughs, some overall patterns are clear. Emissions began to rise in around 1000BC. This corresponds to the spread of Phoenician traders and settlers from their home cities in the Levant into the western Mediterranean, and the consequent exploitation of galena mines in Iberia.

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The rise and fall of Rome is also visible. An increase in lead concentration coincided with Rome’s victories in the Punic wars, against Carthage, the largest Phoenician colony, during in the third and second centuries BC. This was followed by a fall during the civil strife of the first century BC, a rise again when Augustus abolished the Republic and brought the pax Romana of the Empire, and another fall during the third century AD, when the state was engulfed once more by civil war, and also suffered invasion from the east.

The decline in lead pollution was enhanced by Rome’s switch from the silver denarius, which had been increasingly debased with copper, to a gold standard. Even allowing for that, though, the European dark ages, during which Spain was occupied by the Visigoths, are clearly visible in the record—as is the point when civilisation starts to return with the rise of the Frankish state that, under Charlemagne, became the “Holy Roman Empire”, and with the takeover of Spain by the Umayyad caliphate.

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Source: https://www.economist.com/news/science-and-technology/21742687-core-values-arctic-ice-brings-understanding-ancient-europes-economy?fsrc=rss%7Csct

The two ways to measure how fast the universe is growing do not agree

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ONE of the most basic facts about the universe is that it is expanding. This observation, made by Edwin Hubble (pictured) in 1929, leads to all sorts of mind-stretching ideas. That the universe is growing implies it was smaller in the past—possibly a lot smaller. Which leads to the thought that a “Big Bang” kicked everything off. It also opens the question of whether the universe will expand for ever, or will eventually see its expansion halted and reversed by gravity, thus ending in a Big Crunch.

Things got stranger in 1998, when a group of astrophysicists discovered that the rate of expansion is increasing, for this finding raised another question in turn. The acceleration of the expansion was so great that it seemed something was actively pushing the universe apart. Thus was born the notion of “dark energy”—a new component of the cosmos, invoked to balance the equations.

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Trying to work out what dark energy really is (or if it even exists) requires accurate measurements, particularly of the rate at which the universe is expanding. This rate is known as the Hubble constant, and there are two ways of measuring it. Unfortunately, the answers these methods come up with disagree. That is not necessarily a problem. Previous observational conflicts (for example, that the oldest stars in the universe were older than the universe itself) have gone away as measurements improved. But in this case a new set of measurements has confirmed the discrepancy. And that has got those who study astrophysics flummoxed.

The new measurements were made by a team led by Adam Riess, one of the researchers who discovered the accelerating expansion. Dr Riess works at the Space Telescope Science Institute in Baltimore. In a study just uploaded to the arXiv, a repository of papers awaiting formal approval for publication, he and his colleagues offer a new set of measurements of 50 stars of a type known as Cepheid variables.

Cepheids are important to astronomers because they are a rung on what is known as the cosmic distance ladder. A Cepheid pulsates at a frequency related to its intrinsic brightness. This makes it possible, by comparing the intrinsic brightness of such a star with its apparent brightness, as seen from Earth, to work out how far away it is relative to other Cepheids. Then, if the actual distances to some nearby Cepheids can be measured directly, those relative distances can be turned into absolute ones.

This is done by observing their parallax. As Earth orbits the sun, the positions of nearby stars will seem to shift relative to those farther away, in the same way that, to a passenger on a train, trees in the middle distance appear to move with respect to far-off mountains. This means their distances can be worked out by triangulation. The result is a method that has been used since Hubble’s day to work out the distances to nearby galaxies in which individual Cepheids, which are extremely bright stars, can be detected. Then, with this rung in place, other objects, such as certain sorts of supernovae that have predictable energy outputs, can be observed in galaxies of known distance and used to extend the ladder.

The accuracy of the ladder, though, depends on the measurement of each rung. With this in mind, Dr Riess and his colleagues combined data from two space telescopes—Hubble, which has been in orbit since 1990, and Gaia, launched in 2013—to measure with unprecedented accuracy the distances to nearby Cepheids in the hope that this might make the cosmic-ladder-based estimate of the Hubble constant converge with one derived from observations of the Cosmic Microwave Background (CMB), a thin soup of radiation suffusing the universe that is left over from its earliest moments. It did not. Rather, it confirmed the previous estimate.

According to the cosmic ladder, the universe is expanding at a rate of 73.24km per second per megaparsec. (In English, this means that for each additional megaparsec of distance—about 3.3m light years—the speed at which galaxies are moving away from each other rises by 73km per second.) According to the CMB method the rate is 67km per second. That suggests there really is something wrong with current understanding of the universe. Perhaps this is no more than a mismeasurement of one of the other steps on the cosmic distance ladder. But it could be quite profound. Which is good news for the employment prospects of astrophysicists.

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Source: https://www.economist.com/news/science-and-technology/21742689-and-suggests-understanding-cosmology-wrong-two-ways-measure-how?fsrc=rss%7Csct

The world’s lightest wireless flying machine lifts off

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DRONES are getting ever smaller. The latest is the first insect-sized robot to take to the air without a tether delivering its power.

To get their device aloft, Sawyer Fuller of the University of Washington, in Seattle, and his colleagues, who will be presenting their work at the International Conference on Robotics and Automation in Brisbane later this month, had to overcome three obstacles. One is that the propellers and rotors used to lift conventional aircraft are not effective at small scales, where the viscosity of air is a problem. A second is that making circuitry and motors light enough for a robot to get airborne is hard. The third is that even the best existing batteries are too heavy to power such devices. Nature’s portable power supply, fat, packs some 20 times more energy per gram than a battery can.

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In 2013 Dr Fuller, then at Harvard, was part of a team which overcame the first of these hurdles, making a robotic insect that weighed just 80mg. The team copied nature by equipping their device with a pair of wings which flapped 120 times a second (close to the frequency of a fly’s wing beat). They partly overcame the second hurdle by doing away with conventional motors and driving the wings using a piezoelectric ceramic that flexes in response to electrical currents. The third, however, stumped them. Their drone was powered by means of a thin cable—and this cable also served to send control signals from equipment too heavy to be installed on the drone.

Dr Fuller and his new colleagues have now—almost—cracked the remaining problems. They have made the electronics which flap the wings lighter, by cutting the circuitry from copper foil using a laser, rather than printing the pattern onto a base. They have also added an 8mg solar cell to their device. Focusing a laser on this cell lets them power the robot without wires. They have dubbed their gizmo “RoboFly”.

The caveat is that, because they have not yet developed a way to make the power laser track the drone, as soon as it flies out of the beam it drops unceremoniously to the bench top. Solving this should not, however, be too hard—and once it is done they hope RoboFly will be flapping happily around their laboratory.

After that, it is a question of adding sensors and a communications capability to permit their tiny automaton to be controlled remotely, so that it can actually be used for something. The result, the team think, will be sure to make a buzz.

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Source: https://www.economist.com/news/science-and-technology/21742557-robofly-unleashed-worlds-lightest-wireless-flying-machine-lifts?fsrc=rss%7Csct