A new way to classify dinosaurs

AS EVERY school-aged aficionado of dinosaurs knows, those terrible reptiles are divided into two groups: the Saurischia and the Ornithischia—or, to people for whom that is all Greek, the lizard-hipped and the bird-hipped. The names go back 130 years, to 1887, when they were invented and applied by Harry Seeley, a British palaeontologist.

Seeley determined that the arrangement of the bones in a dinosaur’s pelvis—specifically, whether the pubic bone points forwards (Saurischia) or backwards (Ornithischia)—could be used to assign that species to one of these two groups. In his view, and that of subsequent palaeontologists, the evolution of other features of dinosaur skeletons supported the idea that these two hip-defined groups were what are now referred to as clades, each having a single common ancestor. Seeley thereby thought he had overthrown the dinosaurs as a true clade themselves: he believed Saurischia and Ornithischia were descended separately from a group called the thecodonts.

Subsequent analysis suggests he was wrong about that. The dinosaurs do seem to be a proper clade, with a single thecodont ancestor. But the basic division Seeley made of them,…Continue reading
Source: Economist

Powerful whirlwinds explain an odd feature of the Atacama desert

Crystal clear?

THE Salar de Gorbea, at the southern end of the Atacama desert, in Chile, is one of the most hostile places on Earth. It receives virtually no rainfall and the little water it does host is contained in ponds both acidic and salty. It therefore has no vegetation. It is, though, the site of some of the most extraordinary dunes on Earth.

Most dunes are made of sand: grains of silica that are 2mm across, or less. There are exceptions. The White Sands National Monument in New Mexico, for example, is so called because the ingredients of its dunes are sand-grain-sized crystals of gypsum. But this exception proves the rule, because the point about a dune is that it is created by the wind, and when it comes to minerals, the wind can generally pick up and move around only sand-sized objects. The dunes of Salar de Gorbea, however, are an exception that proves no rule at all. They, too, are white, because they are also made of gypsum. But the gypsum in question includes crystals more than 20cm long. How such dunes could form by wind action has long been a mystery. Kathleen Benison, of West Virginia University, thinks, however, that she has solved…Continue reading
Source: Economist

The findings of medical research are disseminated too slowly

ON JANUARY 1st the Bill & Melinda Gates Foundation did something that may help to change the practice of science. It brought into force a policy, foreshadowed two years earlier, that research it supports (it is the world’s biggest source of charitable money for scientific endeavours, to the tune of some $4bn a year) must, when published, be freely available to all. On March 23rd it followed this up by announcing that it will pay the cost of putting such research in one particular repository of freely available papers.

To a layman, this may sound neither controversial nor ground-breaking. But the crucial word is “freely”. It means papers reporting Gates-sponsored research cannot be charged for. No pay walls. No journal subscriptions. That is not a new idea, but the foundation’s announcement gives it teeth. It means recipients of Gates’ largesse can no longer offer their wares to journals such as Nature, the New England Journal of Medicine or the Proceedings of the National Academy of Sciences, since reading the contents of these publications costs money.

That will hurt. Publication in…Continue reading
Source: Economist

An outbreak of yellow fever in Brazil

“ALL gone,” sighs Valmir Rossman as he scans the jungle surrounding his holding outside Santa Maria, a village in the state of Espírito Santo, north-east of Rio de Janeiro. Mr Rossman is a coffee farmer. Afternoons at his plantation used to echo to the calls of howler monkeys (pictured above) proclaiming their territories to potential interlopers. Since mid-February, however, he says he has neither heard nor seen a single one of them—except for two fresh carcasses he stumbled across where the coffee bushes give way to Atlantic rainforest, in the hills that mark the plantation’s edge.

Espírito Santo’s howler-monkey population is crashing. Mr Rossman’s corpses are two among 900 found this year by Sergio Mendes, a primatologist at the state’s federal university (UFES), and his team. In a typical year Dr Mendes would have expected his searchers to come across perhaps half a dozen such bodies during the same period. And something similar is happening in Minas Gerais, Espírito Santo’s inland neighbour. Analysis of the remains suggests the culprit is yellow fever.

It is easy to think of yellow fever, a mosquito-transmitted viral…Continue reading
Source: Economist

Strange signals from the sky may be signs of aliens

ON AUGUST 24th 2001 the Parkes Observatory, in Australia, picked up an unusual signal. It was a burst of radio waves coming more or less from the direction of the Small Magellanic Cloud, a miniature galaxy that orbits the Milky Way. This burst was as brief as it was potent. It lasted less than 5 milliseconds but, during that period, shone with the power of 100m suns. It was, though, noticed by astronomers only in 2007, when they were poking around in Parkes’s archived data. As far as they can tell, it has never been repeated.

Similar unrepeated signals have since been noted elsewhere in the heavens. So far, 17 such “fast radio bursts” (FRBs) have been recognised. They do not look like anything observed before, and there is much speculation about what causes them. One possibility is magnetars—highly magnetised, fast-rotating superdense stars. Another is a particularly exotic sort of black hole, formed when the centrifugal force of a rotating, superdense star proves no longer adequate to the task of stopping that star collapsing suddenly under its own gravity. But, as Manasvi Lingam of Harvard University and Abraham Loeb of the…Continue reading
Source: Economist

A new job for DNA

WHAT lies beneath? It is a pressing question for those prospecting for oil, planning shale-fracturing or seeking geothermal-energy sites. Underground reservoirs of water, oil and gas are connected in extensive, circuitous networks that can change with time or with drilling. Knowing those networks’ particulars can make a big difference to beliefs about how much can safely be extracted from them.

To acquire such knowledge, drillers often use tracers. These are materials that can be injected into the ground in small amounts at one point and then detected reliably if they turn up in other places—thus showing that those places have subterranean links to the point of injection. The supply of decent tracers, however, is limited. About 100, mostly dyes or mildly radioactive materials, are in routine use. This constrains the number of possible injection points in a particular area, and thus the amount of tracking that can actually be done. Yet in many cases—for example, a long well that runs horizontally through a particular rocky stratum—more than 100 injection points might ideally be required. The numerical constraint on tracers extends, moreover,…Continue reading
Source: Economist

The ecological impact of spiders

A light snack

ARACHNOPHOBIA is a common and powerful fear. Spiders sit high in the pantheon of species that have an outsized terror-to-danger ratio. But, unsettling though they may be, the eight-legged do excel at keeping six-limbed pests in check. They prey upon insects in vast quantities, while, for the most part, leaving people alone. Indeed, in 1957 William Bristowe, a British arachnologist, wondered whether British spiders might kill prey equivalent in mass to all of the people then living in Britain.

In research published this week in the Science of Nature, Martin Nyffeler of the University of Basel, in Switzerland, and Klaus Birkhofer of Lund University, in Sweden, attempt to put some numbers on spiders’ dining habits. Starting with the available data on the mass of spiders found per square metre in Earth’s main habitat types—forests, grasslands, fields of crops and so on, they calculated the amount of prey required in each habitat to support the weight of spiders there, based on spiders’ known food requirements per unit of body weight. That done, they extrapolated their habitat-based…Continue reading
Source: Economist

An insect’s eye inspires a new camera for smartphones

Ready for my close-up

MALES of a species called Xenos peckii have an unusual eye for the ladies. X. peckii is a member of the Strepsiptera, a group of insects that parasitise other insects. Its victim of choice is the paper wasp, inside the abdomen of which it develops from larva to adult by eating its host from the inside. Females of the species are blind—there is, after all, little to see in their abode. But males have a pair of eyes (see picture) that are unique to the Strepsiptera, and vital for one brief and important task. When he matures, a male X. peckii must leave his host and find a mate quickly, because he will die within a few hours. A group of researchers working for the Fraunhofer Society, a German government research organisation, have now copied the way male X. peckii eyes work, and used the method as the basis of a new miniature camera for smartphones.

Many animals (human beings and octopuses are good examples), have eyes that use a single lens to focus light onto a sheet of receptor cells at the back of the eye, called a retina, to form an…Continue reading
Source: Economist

Aluminium batteries could let submarine drones range farther

MUCH is made of the potential of flying drones. But drones are useful at sea, too. Unmanned underwater vehicles (UUVs), as they are known technically, are employed for things ranging from prospecting for oil and gas to naval warfare. Like their aerial cousins, though, ocean-going drones have limited ranges—limits that are often imposed by their batteries.

At the moment those batteries are usually either alkaline or lead-acid. Lithium-ion batteries, fashionable elsewhere, have not conquered the UUV world. Their tendency to catch fire counts against them. And they are sensitive to pressure, which is undesirable in devices that operate underwater. But a firm in Massachusetts, called Open Water Power (OWP), is offering an alternative: batteries based on aluminium. With these, its engineers hope to extend the ranges of underwater drones tenfold.

Each of OWP’s battery cells has a block of aluminium as its anode. The cell’s cathode is made of nickel. In a working battery, these anodes and cathodes alternate, and are bathed in an electrolyte made of seawater with some potassium hydroxide dissolved in it. This chemical keeps the battery…Continue reading
Source: Economist

The rise of the medical selfie

OF THE millions of photos shared online every day, which most faithfully represent their subjects? The popular #nofilter hashtag would suggest it is those that have not been digitally altered. But photographs of the same thing can differ greatly, depending on ambient light and the distance and angle they were taken from. So the right manipulation can actually make a picture more honest—and therefore more useful for medical purposes.

That is the idea behind an app from Healthy.io, an Israeli firm. Dip.io, as this app is known, uses mobile-phone cameras for clinical-grade urine analysis. The patient follows the instructions, waits for the colours on the dipstick to develop and then takes a picture of it against the background of a proprietary colour card. The app uses the card to correct the colours so that the dipstick appears as if in a neutral, standard ambient light. The result is then analysed automatically, in light of the patient’s medical history. If this analysis suggests a consultation or prescription is needed, that can also be arranged automatically.

The first urine-dipstick test was developed in 1956, to look for glucose,…Continue reading
Source: Economist