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A round-up of the latest science and news from Australasia.

Early Signs of Arthritis in the Mouth

A common gum disease may indicate a person’s risk of developing rheumatoid arthritis later in life, according to a report published in Medical Hypotheses.

Toad-Proof Fence

Toad-proof fences around dams can prevent the pests from cooling down in the hot, arid zones of Australia, killing them in large enough numbers to stop their spread. “This is the first study to demonstrate long-term control of cane toads,” says A/Prof Mike Letnic of UNSW

Dark Matter Estimates for the Milky Way Halved

A new measurement of dark matter in the Milky Way has revealed there is half as much of the mysterious substance as previously thought.

Astrophysicist Dr Prajwal Kafle of The University of Western Australia node of the International Centre for Radio Astronomy Research probed the edge of the Milky Way, looking closely for the first time about 5 million trillion kilometres from Earth, and found that the weight of dark matter in our own galaxy is 800 billion times the mass of the Sun.

Glaciers Reveal the Regional Nature of Climate Change

Research into the survival of New Zealand’s glaciers at the end of the last ice age has revealed that climate change in the Northern Hemisphere does not directly affect the climate in the Southern Hemisphere. Indeed, the study showed that future changes to climate may have different impacts in the two hemispheres, so a generalised global approach isn’t the solution to climate issues.

When the Universe Cooled

An international team has found evidence that the Universe broke its rising “fever” and began to cool about 11 billion years ago.

New Life for Old Malaria Drug

Chloroquine could be given a new lease of life as an anti-malarial treatment simply by being administered differently.

The parasite that causes malaria has developed resistance to chloroquine, but research carried out at the Australian National University has shown that the parasite protein that causes resistance has an Achilles’ heel. “We studied diverse versions of this protein, and in all cases found that it is limited in its capacity to remove the drug from the parasite,” said Dr Rowena Martin. “This means malaria could once again be treated with chloroquine if it is administered twice-daily rather than just once a day.”

Fluorescent Biosensor Lights Up Cancer

Researchers from the Garvan Institute have developed a mouse that expresses a fluorescing biosensor in every cell of its body, allowing diseased cells and drugs to be tracked and evaluated in real time and in three dimensions.

The biosensor mimics the action of a target protein known as Rac, which drives cell movement in many types of cancer. Rac behaves like a switch: when it’s active, the biosensor picks up chemical cues and glows blue. When Rac is inactive the biosensor glows yellow.

Using sophisticated imaging techniques it is possible to follow Rac activation in any organ at any time, or watch moment-by-moment oscillation of Rac activity at the front or back of cells as they move in the body. This technology has been used to monitor Rac activity in many organs in response to drug treatment.

Penguins Retreat from Sea-Ice

By Stephen Luntz

For the first time, emperor penguins have been found nesting on ice shelves, sometimes 40 metres above the ocean rather than the much lower sea-ice they normally frequent.

It is unknown if this is a well-established behaviour that has not been observed before, or a response to global warming.

Although breeding colonies have been spotted on small islands, a paper in PLoS One notes: “Emperor penguins have previously been considered sea-ice obligate species”. However, the authors report that four colonies have now been spotted on ice shelves.

Two colonies are newly discovered and have only been observed on shelves, while another two have been seen shifting to ice shelves in years when sea-ice conditions are poor.

Small Crater Responsible for the Great Dying

By Stephen Luntz

An Australian scientist believes he has identified the crater responsible for the greatest extinction in our planet’s history.

The crater was once considered far too small to have caused the event known as The Great Dying, but a new angle suggests that its formation might indeed have been the cause.

The Chicxulub crater in Mexico is thought to have been formed by the asteroid that wiped out the dinosaurs. However, one-quarter of the animal and plant species alive during the Cretaceous survived that event.

Sneaky Males Switch on Their Female Brain

Researchers at The University of Otago have observed how males of some species disguise themselves as females in order to improve their chances of mating.