Australasian Science: Australia's authority on science since 1938

Browse in Brief

By Stephen Luntz

Brief bites of science news for subscribers only.

First Oxygen Dated
The first substantial oxygen appeared in the atmosphere 2.48–2.32 billion years ago, A/Prof Mark Barley of the University of WA has concluded in work published in Nature.

The timing of the Great Oxidation Event, in which enough oxygen entered the atmosphere to affect the planet’s chemistry, has been hotly contested. Ratios of molybdenum, rhenium and uranium in the Hamersley Range place it at 2.5 billion years ago according to one study (AS, Nov/Dec 2007, p.13). However, other estimates are as early as 2.7 billion years ago.

The presence of oxygen can be detected because “aerobic-respiring bacteria which oxidise pyrite released acid that dissolved rocks and soils on land, including chromium, that was then carried to the oceans by the flow of water,” Barley said. The presence of chromium in sedimentary rocks indicates the presence of these bacteria.

Barley claimed that older estimates are a result of alterations to the rocks. “The banded iron formations have good representation of the geochemistry in the earth’s early ocean, but also a lot of [formations] were later altered.”

Bodybuilding Supplement Saves Muscle
L-tyrosine, an amino acid popular with bodybuilders, improves muscle strength and mobility in mice with a wasting disease.

Prof Edna Hardeman of the University of NSW Neuromuscular and Regenerative Medicine Unit led a team that created a genetically modified mouse model with the same genetic changes and symptoms as children with nemaline myopathy (NM). NM is the most common congenital muscle wasting disease, delaying motor development and causing weakness in the limbs, face and throat muscles.

“These mice and have a remarkably similar disease profile to the children, with many of the animals dying young,” said Hardeman. “L-tyrosine is readily available, it is easy to administer, and our data suggest that long-term use is relatively safe.”

The research was published in Brain.

Push-off for Push-Ups
Long-standing fitness assessments, such as the number of push-ups or chin-ups someone can do, are a poor predictor of performance at strength-based tasks, Defence Science and Technology Organisation researcher Greg Carstairs has told the 2011 Defence Human Sciences Symposium.

“Assessments that are directly relevant to specific tasks give a better indication of a person’s ability to perform a role. This means that the person can perform more effectively with a reduced risk of injury,” said Carstairs.

Carstairs argues that accurate tests will be particularly important with the opening of combat roles to women, enabling assessments based on the factors that count rather than gender. He says that the “box lift and place” test represents a better indication of the sort of strength needed during combat.

Muscles Buckle Better
Ultrasound images have overturned longstanding notions of how muscles operate. Instead of muscle fibres lying in straight lines, they buckle when at rest.

“This contradicts previously accepted models of how muscles work, and has never been observed before,” says Prof Simon Gandevia, a muscle function expert at Neuroscience Research Australia. “This new understanding will allow us to build more accurate models of muscle function.”

Besides being a reminder of how many relatively basic bodily operations remain poorly understood, Gandevia says the finding “may also help us better understand conditions with poor muscle performance due to abnormalities in muscle length, such as spasticity in cerebral palsy and multiple sclerosis.”

Southern Ocean Warmer and Fresher
The Southern Ocean is changing in a manner in keeping with Climate Change predictions. An Antarctic Climate and Ecosystems summary of the latest research reports that the Southern Ocean is warming faster than the global oceanic average, and the warming is extending to greater depths as a result of local currents.

Other findings are that the Southern Ocean takes up 40% of the carbon dioxide absorbed by the oceans, and salinity is falling as a result of increased rainfall. The latter matches a long-standing prediction of climatic models. pH levels are falling, and this is affecting shell, skeleton and reef construction, particularly in colder environments.

Moon Mineral Found in WA
Tranquillityite, a mineral first found on the Moon, has been discovered at six locations across Western Australia.

When NASA astronauts brought back lunar rocks, three minerals then unknown on Earth were found among them. Two were fairly quickly detected on Earth, but tranquillityite remained unknown until Prof Birger Rasmussen of Curtin University found examples among hundreds of samples he studied.

Having studied tranquillityite in lunar rocks, Rasmussen was familiar with the conditions under which it was likely to be found, and expressed surprise no one had located it previously.

While tranquillityite is unlikely to have any commercial value, Rasmussen says it is useful for dating the age of rocks in which it is found, and has already been used to increase the age estimates for deposits located underneath some of the tranquillityite samples.

On-Site Pesticide Check
A test that can be conducted in the field for the presence of pesticides in waterways could make it much easier to keep lakes and rivers clean, or at least prevent consumption of contaminated water.

“With diminishing water reserves and increasing pesticide use, our waterways are at growing risk of contamination,” said Dr David Beale of RMIT’s School of Applied Sciences. “Typical pesticide monitoring involves collecting samples on-site then taking them back to a laboratory for analysis, a process that can take several days.”

Beale has used chemiluminescence to detect triazinone, triazines and organophosphates at quantities below the safe drinking guidelines. While confirmation and identification of the specific pollutant would require traditional laboratory techniques, Beale believes his work will lead to an easily portable detector that will enable the early detection of polluted water.

Police Need Sleep
Testing of American police officers reveals that more than 40% have sleep disorders, most of which were not being treated. Publication of the research in the Journal of the American Medical Association has led to calls for changes in work practices.

Lead author A/Prof Shantha Rajaratnam of Monash School of Psychology and Psychiatry said: “We found that excessive sleepiness was common in police officers, and that almost half reported having fallen asleep while driving and about 25% reported that it occurred at least monthly”. Uncontrolled anger towards suspects can also occur as a result of poor sleep.

One-third of officers in the study had obstructive sleep apnoea (OSA), while others suffered from insomnia. Not surprisingly, shift work disorder was common.

“Those who screened positive for OSA were 1.5–2 times more likely to have cardiovascular disease and diabetes,” said Dr Laura Barger of Brigham and Women’s Hospital in Boston. Rajaratnam said Australian police might be similarly affected.

Childless Women Average Poorer Health
Women who have not had children are more likely to experience poor health, a study published at Biomed Central has found.

Oddly, childless women were more likely to have better physical functioning but report less vitality and social functioning and poorer mental and general health.

“While the results of our study might not paint a rosy picture, they do not mean that childlessness is a health hazard for women,” stressed Dr Melissa Graham of Deakin School of Health and Social Developments. “These findings may be a reflection of a number of different factors.” Causality may run the other way, with women in poorer health less likely to have children.

Graham also notes that social pressures towards having children may contribute to the findings. “Our previous research, along with that by others, with women who did not have children suggested that childlessness is perceived predominantly negatively, and this may have consequences for the health of childless women,” she said.

Phone App Restores City
A new mobile phone application allows residents and visitors to Christchurch to see the city as it was before the earthquake. Developed by staff and students at the University of Canterbury, the app provides photographs, three-dimensional models and text about the buildings that have gone.

“Following the earthquakes, many buildings in the inner city have been demolished to make way for reconstruction,” said Prof Mark Billinghurst of the Human Interface Technology Lab NZ. “Even for people who have lived in Christchurch all their lives it is difficult to walk through the city and remember what buildings used to be there. Using CityViewAR people can see virtual 3D models of what buildings looked like pre-earthquake.”

The app combines GPS and compass sensors from the smartphone with live video of Christchurch locations, allowing people to take a virtual tour, as well as being reminded when walking the streets in real life. A planned additional feature will provide feedback to architects and town planners on what people want as the city is rebuilt.

First Light For Imaging System
The first images have been obtained from the University of Technology, Sydney’s DeltaVision OMX Blaze super resolution imaging system. This is a world-first technology capable of obtaining real-time colour images of changes in living cells, including those in response to the presence of microorganisms.

“This new imaging platform is truly amazing. We are at the forefront of being able to actually see infectious disease processes at sub-micron level resolution level in living cells,” said i3 Institute Director Professor Ian Charles.

“This will enable research aimed at better understanding how microorganisms such as malaria, bacteria and viruses cause infection, and has the potential to help develop treatments for life-threatening diseases.”