Rising US maize yields due to skewed gains

Rising yields in the US Corn Belt are probably due to the adoption of precision agriculture and disproportionate gains on better soils, a newly developed satellite analysis has shown.

The analysis quantified yield heterogeneity both within and between fields for maize and soybean in the US Midwest. It revealed that heterogeneity in maize yields is rising, with average yield differences between the best and worst soils more than doubling since the turn of the century.

That is both good and bad news, according to David Lobell of Stanford University, US. “It’s good that yields have kept rising, and it’s good that farmers are adopting precision agriculture,” he said. “But there are potential problems with relying on a narrowing base of land for gains, just like in the economy there is a problem of relying on growth only [in the] top income brackets. Generally speaking, broad-based growth is more stable and sustainable.” […]

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When loops become strings

What if our two best hopes for a theory of everything turn out to be the same? Jon Cartwright pulls at the threads

AS THE bell rings for the final round, both fighters are in their corners. The heavyweight champion is panting, against the ropes. The underdog is sprawled on the opposite side, bruised, tired but determined.

Everyone is expecting an exhilarating finale. The challenger has put on a good show, landing a few square punches. Admittedly, it was accused of cheating by ignoring the rules of physics. But that was nothing compared with the favourite’s big trick: dancing in seven invisible dimensions.

This is no ordinary fight: it’s for the honour of successfully explaining the fundamental make-up of the universe. The heavyweight incumbent is string theory, a complex construct that has long had pretensions to be “theory of everything”. The upstart contender, loop quantum gravity, has more modest aspirations – but could still change the face of physics as we know it.

Physicists have long believed they must pin their hopes on just one contender. But as the two rivals walk back into the ring, there’s a turn-up for the books: they reach out for a handshake. If the latest indications are right, it seems the two theories are not so different after all. They might in fact be the same theory in disguise – with implications that reach far and wide. “The next revolution in physics is going to come from people who can cross the  boundary,” says Laurent Freidel, a theorist at the Perimeter Institute in Waterloo, Canada. […]

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Location of El Niño linked to Indonesian fires

Scientists in the US and Taiwan have shown that the occurrence of fires in Indonesia is linked to the location, not the strength, of El Niño weather events.

The study, which examined Pacific El Niños over nearly two decades, revealed that El Niños generating sea-surface temperature anomalies over the eastern Pacific are more likely to result in fires than those generating anomalies over the central Pacific.

“We suggest that projecting the location of El Niño events might be more important than projecting their strength for fire management in southern Borneo,” said Min-Hui Lo of the National Taiwan University in Taipei. […]

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Cine-MRI tracks heart motion

Researchers in France and China have adapted a technique from video processing in computer vision to study regional motion in cine-MRI. The technique, which involves the extraction of intensity parameters such as local magnitude, phase and orientation, could help in the diagnosis of patients with heart failure.

Regular MRI allows clinicians to observe tissue inside the body, but as it does not record information in real time it is poorly suited to study moving organs, such as the heart. To get around this limitation, cine-MRI takes sequential images of the heart during the cardiac cycle using an electrocardiogram as a trigger; the patient is also asked to hold his or her breath so that additional movement is not generated by inhaling or exhaling. The result is a two-dimensional film of a slice of the heart during a beating cycle. […]

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Cine-MRI tracks heart motion

Researchers in France and China have adapted a technique from video processing in computer vision to study regional motion in cine-MRI. The technique, which involves the extraction of intensity parameters such as local magnitude, phase and orientation, could help in the diagnosis of patients with heart failure (Phys. Med. Biol.61 8640).

Regular MRI allows clinicians to observe tissue inside the body, but as it does not record information in real time it is poorly suited to study moving organs, such as the heart. To get around this limitation, cine-MRI takes sequential images of the heart during the cardiac cycle using an electrocardiogram as a trigger; the patient is also asked to hold his or her breath so that additional movement is not generated by inhaling or exhaling. The result is a two-dimensional film of a slice of the heart during a beating cycle. […]

The rest of this article is available here.

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Warming has little effect on maize yields

High temperatures are not a sizeable direct cause of lowered maize yields, but a lack of water is. That’s the conclusion of a US study that attempted to disentangle the effects of temperature and water stress in previously reported yield losses.

“Our study indicates that so long as the crop had sufficient water, the high air temperatures experienced during the study period were not reducing maize yields,” said Elizabeth Carter of Cornell University, US.

More maize is produced than any other crop worldwide, and demand is expected to rise in the developing world by 50% by the middle of the century. Over the same period, average global temperatures are expected to increase by some 2°C. […]

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Waking up to the cosmic dawn

Across Europe, some 10 000 antennas stand courtly, like squat flag poles. They may not look like much, but they are in a sense an incredibly powerful time machine.
Known collectively as the Low-Frequency Array (LOFAR), the antennas are receiving radio signals that have travelled billions of years to get here, from the depths of the cosmos. That means they are looking billions of years into the past, when the universe was almost featureless – and when planets, stars or galaxies didn’t exist.

Because light travels at a finite speed, all telescopes look into the past to some extent. But astrophysicist Professor Dominik Schwarz of Bielefeld University in Germany, who helped to plan the telescope, said the ‘cosmic dawn cannot be seen with any other instrument’. […]

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Crossing Europe on the hydrogen highway

From Bergen in Norway to Bolzano in Italy, specialised refuelling stations mean that drivers of hydrogen-powered cars can now travel right across Europe.
Hyundai, Toyota and Honda have all developed – and commercialised – cars powered by hydrogen gas. While there are just a handful on Europe’s roads at the moment, that’s all about to change because of a concerted effort to put hydrogen technology into the fast lane.

Hydrogen works in a ‘fuel cell’ to generate electricity, which can drive a car’s wheels via an electric motor, emitting nothing but water vapour in the process.

‘Our activities aim to improve accessibility and interoperability of stations,’ explained Dolly Oladini, the assistant project manager for HyFIVE, one of a group of research projects that are working collectively to deploy thousands of hydrogen vehicles across Europe, and set up dozens of refuelling stations. […]

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