Technology :: Cheetah robot breaks land speed record

YOU can run, but you won't escape... A robot named Cheetah has broken the speed record for four-legged robots by reaching almost 30 kilometres an hour (see the video at bit.ly/robocheet).

Much like a real cheetah, the robot uses a short, hopping gait at low speeds before increasing its stride and pace by flexing and unflexing its back with each step.

Cheetah is being developed by Boston Dynamics of Waltham, Massachusetts, with funding from the US Defense Advanced Research Projects Agency. The current version of the robot is powered by a hydraulic pump and has only been tested on a treadmill, where it is tethered to ensure it stays on track. The firm aims to test a free-running prototype this year.

Last year Boston Dynamics unveiled BigDog, designed as a military pack mule, and the humanoid PETMAN, which runs on two legs and can do press-ups.

Technology :: Tevatron collider's mighty boost for Higgs hunt

EVEN from beyond the grave it is possible to help tease apart the nature of matter. Newly processed measurements from the now defunct Tevatron particle collider have led to the most precise estimate yet of the mass of the W boson. That in turn constrains the mass of the long-sought Higgs boson.

The Tevatron was housed at Fermilab in Batavia, Illinois, and turned off in September 2011, but researchers are still combing through the data it produced.

Their latest sums, combined with earlier data from other detectors, place the W boson's mass at 80.385 gigaelectronvolts, plus or minus 0.015 GeV. The previous estimate was 80.4 GeV, give or take 0.045 GeV.

Thanks to relationships laid out in the standard model of physics - our best picture of the menagerie of particles and forces that make up the universe - the improved W boson mass hones estimates for the mass of the Higgs, the missing piece of the standard model.

Last December, physicists at the Large Hadron Collider at CERN, near Geneva, Switzerland, announced hints of a Higgs with a mass of about 125 GeV. The new W boson mass boosts confidence in that result, as it is consistent with a Higgs weighing between 115 and 127 GeV. "It's all fitting together nicely," says Dmitri Denisov of DZero, one of the Tevatron's two main detectors.

Technology :: Fukushima's fate inspires nuclear safety rethink

The crisis that unfolded at the Fukushima Daiichi nuclear plant after Japan's megaquake and tsunami is rewriting the nuclear safety guide.

The European Union, for instance, has ordered a risk assessment of all nuclear power plants in its member states. These assessments are supposed to consider each plant's ability to withstand a full range of potential hazards – from earthquakes and floods to plane crashes and terrorist attacks.

The Japanese disaster did bring some positive news. The reactors along Japan's Pacific coast suffered no serious damage from the earthquake, even though its magnitude exceeded the worst-case scenarios assumed in their designs. That bodes well for the ability of reactors worldwide to withstand major earthquakes.

But Fukushima Daiichi was doomed by a decision to plan for a maximum tsunami height of only 5.7 metres, well short of the wave of up to 15 metres that engulfed the plant on 11 March 2011. In the light of this error, regulators worldwide are reassessing whether other plants are vulnerable to catastrophic floods, caused by tsunami, swollen rivers or failed dams.

Shake-proofing

Since the Japanese megaquake, much has been made of the fact that many reactors may face quakes that exceed those they were designed to withstand. In the US, the Nuclear Regulatory Commission is giving plant operators in central and eastern parts of the country 18 months to revise their hazard assessments, following a new report reconsidering the risks posed by the region's geological faults.

Although this may result in seismic upgrades at some facilities, the performance of Japan's plants after last year's magnitude-9.0 quake suggests that existing reactors are able to survive ground shaking greater than anticipated by their designers.

Even the Onagawa plant, which sits closer to the megaquake's epicentre than Fukushima, shut down with no major damage. "Onagawa had the world's best stress test, and it seems to have passed," says Peter Yanev, a seismic risk consultant based in Orinda, California.

It was a similar story in 2007, when the Kashiwazaki-Kariwa plant in western Japan was rocked by a magnitude-6.6 quake, and last year, when a magnitude-5.8 quake hit less than 20 kilometres from the North Anna plant in Virginia. Both quakes exceeded the plants' design specifications, yet the reactors remained intact.

This resilience reflects the caution of reactor designers, who build a margin of error into their seismic engineering.

Inadequate flood protection

By contrast, a wall built to withstand a 5.7-metre tsunami offers no protection from a 15-metre wave. And according to those who have analysed Japan's history of tsunamis, the engineers who built Fukushima Daiichi should have known that their protection was inadequate (see graphic).

Johannis Nöggerath, president of the Swiss Nuclear Society, seismologist Robert Geller of the University of Tokyo, and Viacheslav Gusiakov, who heads the Russian Academy of Sciences' Tsunami Laboratory in Novosibirsk, have looked at the historical record of tsunamis that was available when Fukushima Daiichi was designed in the mid-1960s (Bulletin of the Atomic Scientists, vol 67, p 37).

They note that tsunamis rising up to 38 metres had already hit parts of Japan's Pacific coast some 200 kilometres to the north, and say that it would have been prudent to plan for a similar onslaught. Instead, based on waves seen at Fukushima in 1960, generated by a magnitude-9.5 quake across the Pacific in Chile, the plant's designers initially assumed that the worst-case scenario was a 3.1-metre tsunami. That figure was revised to 5.7 metres in 2002.

In a bitter irony, before construction at Fukushima Daiichi began, the site was excavated by more than 20 metres. This was done in part to allow the reactors to be built on bedrock to improve their seismic resilience, but it put the plant directly in harm's way when the tsunami hit.

Worse, the diesel generators needed to power emergency cooling systems, and switching gear that connects the plant to the electricity grid and controls core cooling, were not in waterproof buildings. Once they flooded, a disaster was almost inevitable.

Swiss example

It needn't have been this way. Swiss reactors, which could face flash floods from Alpine rivers, house their backup cooling systems in waterproof bunkers. They also have filtered venting systems so that even if cooling fails and pressure starts to build in the containment building, radioactive iodine and caesium can be removed from the steam before it is released. Had Fukushima Daiichi been designed to similar specifications, says Nöggerath, "I'm convinced that it would have prevented the accident".

Operators of reactors that are vulnerable to severe floods may now decide to follow the Swiss example. But flooding is just one of many possible hazards, some of which are difficult to anticipate. "You always worry about what you haven't analysed," says Chip Lagdon, chief of nuclear safety with the US Department of Energy.

Flora and Fauna :: What made 30 dolphins come ashore in Brazil?

It was just another day on the beach for holidaymakers off the coast of Rio de Janeiro, Brazil, when a pod of about 30 dolphins swam ashore on Monday. Beachgoers quickly came to the rescue, rushing into the sea and dragging the dolphins by their fins and tails into deeper water.

The whole episode was captured by Gerd Traue in a video (above), which has racked up over a million views online.

What can experts learn from the footage? The species involved, for one. These are common dolphins (Delphinus delphis), which typically live a long way off shore, says Mark Simmonds of the Whale and Dolphin Conservation Society, a global charity.

However the video does not reveal what caused the stranding – fishing boats or sonar are two possibilities.

Had experts rescued the dolphins, says Simmonds, they may have examined the individuals for damage, such as net marks, that may have provided clues. But he says the dolphins in the video appear to be healthy.

Out of their depth

The topography of the coastline may have disoriented the dolphins, says Michael Moore of the Wood's Hole Oceanographic Institution in Massachusetts. It would not be surprising if offshore dolphins like these had trouble navigating the sandbars and silty seabeds found in shallow waters.

Nor is it surprising that such a large number of dolphins would head for land together. Dolphins are social creatures, so it would take only one member of the pod to go astray – say, if it was diseased – and the others would follow.

This social behaviour is what makes mass strandings of cetaceans so common. In the last month, for example, 179 dolphins have reportedly been stranded in Cape Cod, Massachusetts.

Call in the experts

Understanding what's going on in such cases is especially hard because scientists must rely largely on postmortem evidence. Moore and others are trying to develop early warning systems to get to the dolphins while they're still alive.

Sensors deployed in regions where strandings are common, for example, could detect the sounds of the cetaceans nearing shore and send a text message warning officials of an imminent stranding.

The Brazilian video has widely been greeted as a good news story. But Simmonds is uneasy about this.

"There's a clock ticking, so it's important to respond quickly, but it's also important to move them in the right ways," he says. Typically it's best not to touch the animals and to call in experts instead, he says. "Pulling their flippers can dislocate their bones, or even pull a flipper right off."

Economyc :: Midlife needn't be a crisis

people may run the world, but you would hardly know it from their public image.

Film-makers and advertisers specialise in admiring portrayals of teens and twenty-somethings, but those in the middle decades of their lives are usually depicted as doing little more than serving time between the turbulence of youth and the decline of old age - and occasionally being tipped into crisis by the sheer ennui of their mundane existence.

The assumption that middle age is a pretty nondescript phase of life seems to have extended to scientists too: paediatricians and gerontologists abound, but there are few "middle-age-ologists".

But look past the spreading waistlines and the reading glasses and it becomes apparent that middle age is actually both rare and remarkable. Humans are the only animals to enjoy a lengthy post-reproductive, pre-decrepitude chapter in our lives. There's a case to be made for looking at middle age as ...

Science :: Metal detector can identify buried bombs

Metal detector could one day tell whether buried objects are unexploded bombs or just harmless junk.

The world is riddled with unexploded bombs left behind following munitions tests and warfare. Governments want to dig them up so the land they are in can be used again. The problem is, "it's difficult to distinguish the unexploded bombs from man-made clutter or junk", says Eugene Lavely of BAE Systems in Burlington, Massachusetts.

Lavely and his colleagues have developed a technique, called time-domain electromagnetic induction, to tell risks from rubbish. Like "a fancy metal detector", it uses a coil to send an electromagnetic pulse 15 metres into the ground, Lavely reported at the American Physical Society meeting in Boston last week. The pulse makes the things it hits reverberate like a struck drum, and the team have identified the reverberation signal of a torpedo-shaped metal object with a hollow core - where explosives may lie.

The researchers are now refining the method so that it is accurate enough to meet US standards, which require 99.9 per cent confidence that all bombs have been dug up before land can be used.