Innovation and Technology Weekly – No. 30, 2014

This is the online version of UNU-MERIT’s I&T Weekly which is sent out by email every Friday. If you wish to subscribe to this free service, please submit your email address in the box to the right.

Issue 30, 2014

This week's headlines:

Paralysed rats walk, orchestrated by computer
September 25, 2014

It's a strange sight: a paralyzed rat walking on its hind legs in a precise cadence, all controlled by a computer. A new study by researchers from Ecole Polytechnique Federale in Lausanne describes their efforts to use electronics to restore fluid, realistic movements to paralysed animals. The study is part of a wider effort to help paralyzed people walk again by zapping their spinal cords with electrical pulses. These signals can replace commands normally sent out by the brain, but which are interrupted when the spinal cord is injured.

This spring, researchers from the University of Louisville and the University of California said four men who had been paralysed for years were able to regain movement in their legs, hips, ankles, and toes, and even stand using an implanted device that stimulated their spinal cords, a technique called epidural stimulation.

A limit to epidural stimulation so far is that the electrical pulses don't produce complex, coordinated movement. Also, in human tests, the stimulators are controlled manually. That's where the new system could come into play. By filming the rats as they walked, the Swiss team fed the images to software that quickly adjusted the pattern of stimulation to produce synchronized stepping movements. Such a system could help a person walk rhythmically and maintain his balance.

To produce their results, the Swiss scientists severed the spinal cords of a half-dozen rats and then implanted flexible electrodes into the lower part of their spinal cords. The animals were also given a serotonin agonist, which readies the spinal cord to communicate with the legs, an ability that's depleted after an injury. With their weight supported by a harness, the rats were placed on a treadmill or on a runway with obstacles. Each of the rats walked at least a thousand successive steps and successfully navigated rodent-sized stairs. The team hopes to test its ideas in a human volunteer next year.

Full story: Technology Review / Science Translational Medicine Back to top

Solar cell powers water-to-hydrogen conversion
September 25, 2014

A class of materials that has quickly become the rising star of the solar cell world could enable production of hydrogen fuel using sunlight. Researchers from the Ecole Polytechnique Federale de Lausanne in Switzerland built a photovoltaic device using cheap and abundant materials called perovskites.

The group created a device that uses sunlight to split water into oxygen and hydrogen gas with 12.3% efficiency. That figure puts the device above the 10% benchmark for useful solar-to-hydrogen conversion. Hydrogen holds promise as clean fuel to power cars or produce electricity.

Over the last five years, perovskites have been found to rival the efficiency and cost of silicon in converting sunlight to electricity. The Swiss team created its device using perovskite cells and a catalyst made from nickel, iron, oxygen and hydrogen.

Perovskite photovoltaics also generate higher voltages than silicon cells, making them better at powering the water-splitting reaction. A similar device developed by MIT researchers used three or four silicon solar cells in series to produce the necessary voltage while the Swiss one used only two.

Full story: Science News / Science Back to top

Your brain waves could reveal what you forgot
September 24, 2014

During interviews and interrogations, detectives often ask subjects whether they recall pieces of information pertaining to a crime or crime scene. Because our brains are constantly processing huge amounts of information, it can be difficult or even impossible to recall data that wasn't salient enough to notice, at least consciously. And if information is incriminating, we might resist voluntarily giving it up.

But what if such information could be extracted without relying on a subject's memory at all? According to a new study by Northwestern University researchers that could be possible via a particular brain wave known as P300, circumventing both our fallible memory and refusal to give up potentially incriminating evidence.

The study examined 24 subjects using a recognition test that examines whether a subject recognizes crime-relevant information. Each subject was equipped with a wearable camera that recorded information over a 4-hour period. The video footage was analyzed by the team. The people were divided into two groups, 12 test subjects and 12 control subjects. For the test subjects, the researchers compiled individual lists of things the test subjects had seen over the course of the day, as well as similar things they hadn't seen.

While there were individual lists for the 12 test subjects, the researchers made a single generic list for the 12 control subjects. The researchers then read items off the list to the subjects, and measured their P300 brain waves. The control subjects, who were presented with a list of things they hadn't seen that day, showed no measurable change in P300 size. When the test subjects heard the name of something they had seen the previous day, the P300 wave appeared larger than when they heard the name of something they hadn't seen.

Full story: CNET / Psychological Science Back to top

Make tough tasks seem easier by zapping the brain
September 25, 2014

We know pupils dilate with mental effort, when we think about a difficult maths problem, for example. To see if this was also true of physical exertion, researchers from the Catholic University of Louvain in Belgium, measured the pupils of 18 volunteers as they squeezed a device which reads grip strength. Sure enough, the more force they exerted, the larger their pupils.

To see whether pupil size was related to actual or perceived effort, the volunteers were asked to squeeze the device with four different grip strengths. Various tests enabled the researchers to tell how much effort participants felt they used, from none at all to the most effort possible. Comparing the results from both sets of experiments suggested that pupil dilation correlated more closely with perceived effort than actual effort. The fact that both mental effort and perceived physical effort are reflected in pupil size suggests there is a common representation of effort in the brain, according to the researchers.

To see where in the brain this might be, the team looked at which areas were active while similar grip tasks were being performed. They were able to identify areas within the supplementary motor cortex - which plays a role in movement - associated with how effortful a task is perceived to be. Next, they used a non-invasive method called transcranial magnetic stimulation to block activity in that area as people repeated the task. The participants made the same actual effort but to them, it seemed significantly easier.

Full story: New Scientist / Frontiers in Behavioral Neuroscience Back to top

Innovative stone tools sprung up multiple times
September 26, 2014

Innovative Stone Age tools may have been developed by people in Eurasia and - contrary to widely held views - not just invented in Africa. A new study shows evidence that refined stone weapons were developed in Armenia about 325,000 years ago.

The find challenges the theory held by many archaeologists that sophisticated stone tool technology came from Africa then spread to Eurasia as the human population expanded. Experts studied thousands of stone artefacts from the Nor Geghi site in Armenia, which sits between two lava flows dated between 200,000 and 400,000 years old. Analysis of volcanic ash and sediment at the site indicated the artefacts were between 325,000 and 335,000 years old.

The tools were crafted using two different technologies. Bifacal technology, used to produce axes during the Lower Palaeolithic, involves chipping away at a mass of stone until the desired shaped is formed. The chips are discarded. The more sophisticated Levallois technology is where a stone is carved into a convex shape and used as a knife or other sharp object. The discarded flakes are used to produce small tools such as sharp points.

The latter technique appears in the archaeological record across Eurasia between 200 to 300,000 years ago during the Middle Paleolithic period, and earlier in Africa during the Middle Stone Age. The presence of the two technologies at the site in Armenia provides the first clear evidence that local populations developed Levallois technology out of existing biface technology, argue the researchers. Chemical analysis of artefacts shows that humans sourced the stones from outcrops up to 120 kilometres away.

Rather than a 'technical breakthrough' that spread from a single point of origin, the evolution of Levallois technology was gradual and intermittent and occurred within different human populations that share a common technological ancestry, according to the researchers.

Full story: ABC News / Science Back to top

Air-chaeological drones search for ancient treasures
September 24, 2014

In August, two small craft swooped over the ruins of Aphrodisias - the ancient Greek city of Aphrodite in Turkey, built in the 1st century BC. As well as precisely mapping the crumbling amphitheatre, the drones also gathered infrared images, looking for buried features of the ancient civilisation.

The craft belong to Drone Adventures, a non-profit organisation in Lausanne, Switzerland, that specialises in exploring the use of drones in new applications, from wildlife management to geography. The organisation uses drones called eBees, which have a 1-metre wingspan and weigh about half a kilogram. They follow a pre-planned route over an area, mapping as they go.

Data that the drones gathered was used to quickly build an accurate 3D model of the ruins above ground. This allowed archaeologists to precisely measure the size of buildings, or the width of ancient streets without expensive surveying. According to Drone Adventures the work the craft perform in a few hours would take months using traditional techniques. Researchers at the Austrian Archaeological Institute in Vienna, which funded the work, are now analysing the infrared data.

Full story: New Scientist Back to top