Canadian scientists probing two sites in the High Arctic have found fresh evidence pointing to a fiery Siberian suspect in the greatest mass extinction of all time - a planet-wide cataclysm that wiped out more than 90 per cent of the Earth's species about 250 million years ago.

The so-called "Great Dying" at the end of the Permian geological era killed off a larger proportion of species than any of the 25 other mass extinctions scientists have identified from sudden and widespread gaps in the fossil record at certain layers of rock corresponding to specific periods of time.

The precise cause of the biological catastrophe 252 million years ago has been debated by scientists for decades. But nothing else in Earth history compares to the Late Permian disaster, which eclipsed 95 per cent of all marine life and about 70 per cent of species on land.

Some have argued that a massive meteorite strike - like the one widely presumed to have triggered the end of the dinosaur age 65 million years ago - must have been to blame. Others point to extreme climate change linked to ocean acidification, oxygen depletion, mercury poisoning or other species-snuffing effects as the main driver of the extinctions.

And without discounting the other forces as potential contributors to the Great Dying, a growing number of scientists - including several groups of Canadian researchers who are among the world's leading investigators of the die-off - have fingered a prolonged series of enormous volcanic eruptions in northern Asia known as the "Siberian Traps" as the main culprit in the Permian extinction.

The interior of a living cell is a crowded place, with proteins and other macromolecules packed tightly together. A team of scientists at Carnegie Mellon University has approximated this molecular crowding in an artificial cellular system and found that tight quarters help the process of gene expression, especially when other conditions are less than ideal.

As the researchers report in an advance online publication by the journal Nature Nanotechnology, these findings may help explain how cells have adapted to the phenomenon of molecular crowding, which has been preserved through evolution. And this understanding may guide synthetic biologists as they develop artificial cells that might someday be used for drug delivery, biofuel production and biosensors.

"These are baby steps we're taking in learning how to make artificial cells," said Cheemeng Tan, a Lane Postdoctoral Fellow and a Branco-Weiss Fellow in the Lane Center for Computational Biology, who led the study. Most studies of synthetic biological systems today employ solution-based chemistry, which does not involve molecular crowding. The findings of the CMU study and the lessons of evolution suggest that bioengineers will need to build crowding into artificial cells if synthetic genetic circuits are to function as they would in real cells.

The research team, which included Russell Schwartz, professor of biological sciences; Philip LeDuc, professor of mechanical engineering and biological sciences; Marcel Bruchez, professor of chemistry; and Saumya Saurabh, a Ph.D. student in chemistry, developed their artificial cellular system using molecular components from bacteriophage T7, a virus that infects bacteria that is often used as a model in synthetic biology.

Discovery Date: July 8, 2013

Magnitude: 16.8 mag

Discoverer: Gennady Borisov (Crimean Laboratory of the Sternberg Astronomical Institute)
The orbital elements are published on M.P.E.C. 2013-N51.

Discovery Date: July 5, 2013

Magnitude: 21.4 mag

Discoverer: Pan-STARRS 1 telescope (Haleakala)
The orbital elements are published at the MPC Ephemerides and Orbital Elements.

Discovery Date: July 4, 2013

Magnitude: 20.7 mag

Discoverer: Pan-STARRS 1 telescope (Haleakala)
The orbital elements are published on M.P.E.C. 2013-N50.

A series of "fast radio bursts" detected by an Australian lab has scientists puzzling over its origin.

Every now and then things go "bump!" in the cosmic night, releasing torrents of energy that astronomers can't easily explain. Not that they mind: most times an energetic riddle flares up in their view of the sky, major epoch-setting discoveries are sure to follow. This was the pattern for pulsars - rapidly spinning city-size stellar remnants that steadily chirp in radio. It was also the pattern for gamma-ray bursts - extreme explosions at the outskirts of the observable universe thought to be caused by stellar mergers and collapsing massive stars. Now the pattern is playing out again, with last week's announcement that an international team of researchers has detected brief, bright bursts of radio waves washing over Earth from mysterious sources that may be billions of light-years away. The findings, reported in the July 5 Science, could open an entirely new window on the universe by allowing scientists to measure the composition and dynamics of the intergalactic medium - the cold, diffuse plasma that lies between galaxies.

Using a year's worth of data gathered from some 10 percent of the sky by the 64-meter Parkes radio telescope in Australia, the team detected four bursts from far outside the galactic plane, each occurring only once and lasting a few thousandths of a second. According to Dan Thornton, a PhD candidate at the University of Manchester in England who led the study, the results suggest that these "fast radio bursts," or FRBs, probably occur as often as every 10 seconds or so, nearly 10,000 times a day. "If we had radio telescopes watching the entire sky, that's how many we think we'd see each day," Thornton says. "We haven't seen more of these until now only because we've been looking at small regions of the sky for small amounts of time."

DARPA's newest military robotic creation is a little too close to our sci-fi imaginations.

Called "Atlas," the robot is designed to travel across rough terrain, use human tools and climb using its hands and feet. DARPA - formally known as the U.S. Defense Department' Defense Advanced Research Projects Agency - is currently challenging teams to create new software for the 6-foot-tall robot's brain.

Biologists at Tufts University have removed the head and brain of a worm by decapitation, and then watched as it regenerated both its head and brain - and, somewhat miraculously, the memories stored inside. At first glance, this finding would seem to confirm cellular memory - the theory that data can be somehow stored by cells that are outside of the brain. More research will undoubtedly have to occur before such a highly contested hypothesis is confirmed, however.

The Tufts researchers tested the memory of planarians, simple flatworms that are renowned for their regenerative properties. These worms can be cut up into pieces, and then each piece will grow into a whole new worm. In a previous study, a piece as small as 1/279th of the original worm regrew into a complete organism within a few weeks.

This astonishing regeneration is due to a large number of pluripotent stem cells, which make up around 20% of the worm. These adult stem cells, called neoblasts, can become any of the cell types required by the regenerating planarian - including brain cells.

While research tends to become very specialized and entire communities of scientists can work on specific topics with only a little overlap between them, physicist Dr Nicolas Brunner and mathematician Professor Noah Linden worked together to uncover a deep and unexpected connection between their two fields of expertise: game theory and quantum physics.

Dr Brunner said: "Once in a while, connections are established between topics which seem, on the face of it, to have nothing in common. Such new links have potential to trigger significant progress and open entirely new avenues for research."

Game theory -- which is used today in a wide range of areas such as economics, social sciences, biology and philosophy -- gives a mathematical framework for describing a situation of conflict or cooperation between intelligent rational players. The central goal is to predict the outcome of the process. In the early 1950s, John Nash showed that the strategies adopted by the players form an equilibrium point (so-called Nash equilibrium) for which none of the players has any incentive to change strategy.

Two new studies of earthquakes near injection wells have seismologists using words rarely heard these days in earthquake science: prediction and warning. The research has also renewed calls for better seismic monitoring and reporting in regions experiencing man-made earthquakes.

"Shale gas operations have completely changed our energy policy and people are injecting in places they've never injected before. If we're going to do this safely, we need to address the environmental issues, including protecting water supplies and earthquake risk," said Cliff Frohlich, a seismologist at the University of Texas Institute for Geophysics who was not involved in the new studies.The two reports appear in today's (July 11) issue of the journal Science.
Links between injection and earthquakes

In the Midwest, researchers discovered a warning signal that moderate-sized earthquakes may strike near injection wells, where mining companies dispose of waste fluids. At three sites in Oklahoma, Colorado and Texas, passing seismic waves from faraway earthquakes - the recent massive temblors in Japan, Sumatra and Chile - triggered swarms of small earthquakes. The seismic activity continued until magnitude-4 and magnitude-5 earthquakes struck, such as the large earthquakes near Prague, Okla., in November 2011.