Friday, 30 March 2007

Genetically modified crops, ten years on

Is the expansion of genetically modified (GM) crops still seen as risky, or will it in fact help with the doubling of the food supply required as Earth’s population hits nine billion within the next 40 years?

Ten years after the first GM crops were planted, evidence is mounting that the technology can increase crop yields with apparently little environmental impact, particularly in developing countries. In India, for example, GM cotton has increased yields by around 150 per cent, trebled small farmers’ profits, and reduced pesticide volumes by 80 per cent. In Australia, GM cotton has also significantly decreased pesticide use while raising farmers’ yields.

Anti-GM groups, however, argue that in many developing countries, GM crops are now grown mainly for export by big farmers, not for local consumption, and that there are big effects of this monoculture cropping.

Most Australian states, including Victoria and New South Wales, have imposed moratoria on GM crops until 2008. But according to a 2005 ABARE report, ongoing moratoria could result in Australia losing billions of dollars in foregone profits over the next decade, particularly as global warming impacts crop environments.

University of Melbourne agronomist Rob Norton claims that the vigorous seedling growth of hybrid GM canolas helps them compete against weeds and shortens the interval to harvest, reducing exposure to heat at the end of the growing season, and meaning less irrigation is required. This trait would allow canola plantings to be expanded into drier areas, potentially boosting annual Australian production of canola by 295,000 tonnes annually.

More information is available from CSIRO's press release


Thursday, 29 March 2007

Present day mammalian ancestors walked in the time of dinosaurs

Scientists have long thought that the mass extinction of the dinosaurs around 65 millions years ago opened the door for modern mammal species to proliferate. But a new, complete 'tree of life' tracing the history of all 4,500 mammals on Earth shows that they did not diversify as a result of the death of the dinosaurs, researchers claim.

The study, conducted by an international team of researchers from Munich, the U.S., the U.K. and Australia, contradicts the previously accepted theory that the Mass Extinction Event (MEE) that wiped out the dinosaurs 65 million years ago prompted the rapid rise of the mammals we see on the earth today.

“This is the first time such a large history of mammal evolution has been constructed,” said team member Marcel Cardillo, a visiting fellow at the School of Botany and Zoology at The Australian National University.

By comparing data from a range of sources including the fossil and molecular records, the researchers show that most existing mammal orders first appeared between 100 and 85 million years ago, well before the meteor impact that is thought to have killed the dinosaurs.

However, throughout the Cretaceous epoch, when dinosaurs walked the earth, these mammal species were relatively few in number, and were prevented from diversifying and evolving in ecosystems dominated by dinosaurs, scientists say.

The tree of life shows that after the MEE, certain mammals did experience a rapid period of diversification and evolution. However, most of these groups have since either died out completely, such as Andrewsarchus (an aggressive wolf-like cow), or declined in diversity, such as the group containing sloths and armadillos.

The researchers believe that our 'ancestors', and those of all other mammals on earth now, began to radiate around the time of a sudden increase in the temperature of the planet – ten million years after the death of the dinosaurs.

“Our study shows that modern mammal ancestors appeared millions of years before the dinosaurs disappeared, and then chugged along at low rates of species diversity for many more millions of years before exploding into the multitude of species we see today,” Cardillo said.

Cardillo said it would take many more years of study to find out the reasons why modern mammal ancestors were around for so long before they diversified, but suggested that it could be the result of complex relations between mammals and other animal species, and variations in the Earth’s climate, geology and atmosphere.

More information is available from the Australian National University’s press release.


Wednesday, 28 March 2007

Cane toads invade new Australian terrain

As the nursery rhyme goes, there was an old lady who swallowed a fly. To catch the fly, she swallowed a spider. To catch the spider she swallowed a bird … and so on, until she died, of course.

Cane toads first reached Australian soil under similar premises. When they were introduced to the Northern Territory in 1935, they were expected to combat the cane beetle, which is a pest of sugar cane crops. While the toads did not alleviate the problem with beetles, they did quickly become accustomed to the Australian climate, and they bred fast. Farmers soon found themselves faced with larger, wartier pests than cane beetles – the cane toads themselves.

For the past 70 years, residents of Perth and Adelaide have watched cane toads spread from the Northern Territory through tropical Australia, and thought it had nothing much to do with them. But new research by an international team of scientists, including ecologist Rick Shine of the Sydney University’s School of Biological Science, claims otherwise.

March of the toads

Previous predictions about the behaviour of cane toads, which go by the scientific name Bufo marinus, indicated that the species would be limited to tropical environments like those in Central and South America, from which the toads were originally imported.

Confounding these beliefs, the toads were now found to have adapted to dry conditions and temperatures ranging from 5 to 27 degrees Celsius.

“The toads have adapted rapidly to Australian conditions, and now tolerate much higher temperatures than was the case when they first arrived on our shores in 1935,” Shine said. “As a result, toads have managed to spread much further, into climatic zones also found widely through southern Australia – so there is no reason to think they will remain only in the tropics.”

Mathematical modelling by Shine and his team shows now predicts that toads will be able to live and breed in large areas of Western Australia, South Australia and western Victoria, and in several pockets along the New South Wales coast.

Current and projected range of invasive cane toads in Australia - Rick Shane et al

The researchers estimate the toads’ range to be about 1.2 million square kilometres across the Northern Territory and Queensland. This is a dramatic increase from estimates made by the same research team a little over a year ago, in which cane toads were thought to have spread to more than a million square kilometres in tropical and sub-tropical Australia.

Additionally, the rate at which cane toads are invading is not only fast – it’s also getting faster, researchers found. Compared with a rate of only 10 kilometres a year in the 1940s, the toads are now found to be advancing at more than 50 kilometres annually. Researchers speculate that this could be a result of evolution, as toads with longer legs were found to have an evolutionary advantage over shorter-legged counterparts.

Beware warty hitch-hikers

Most of the potential range of the cane toad in southern Australia is separated from the toads’ tropical range by very large expanses of desert, which the researchers expect to be too dry for a toad to cross.

But although the toads may initially be deterred by these dry expanses, Shine said it is likely that the toads will cross such areas as hitch-hikers among rubbish or equipment in the back of a truck.

According to Shine, a nationwide invasion of cane toads is ‘inevitable’.

“[The arrival of cane toads] will probably depend upon fortuitous hitch-hiking events, rather than the toads dispersing all the way under their own steam,” he said. “The toads are superb invaders, and so far, none of the attempts to slow them down seem to have been very successful.”

Due to their toxicity and eating habits, the arrival of cane toads could spell bad news for some native fauna, pets and large predators. However, Shine expects most species to be relatively unaffected.

“Our work in the Northern Territory indicates that the toads dramatically affect only a few species,” he said, “[which are] mostly large predators like goannas, that try to eat the toads and are poisoned as a result.”

The spread of cane toads is expected to provide a good model system for understanding what invasive species will do in general, Shine said. Researchers are now expecting similar shifts in other invaders as well, as they adapt to the Australian climate.


Tuesday, 27 March 2007

Genetically modified pigs could yield organs for human bodies

Recent medical advances may shine new hope on the otherwise dismal shortage of human organ donors, by allowing the organs of animals to be transplanted into human bodies instead. It may be awhile yet before the technology, known as xenotransplantation, reaches medical clinics; but when that happens, accusing someone of being pigheaded may take on a new meaning altogether.

Xenotransplantation has been studied and attempted for over a century, but few operations have been successful to date. According to Muhammad Mohiuddin, who studies xenotransplantation at the U.S. National Heart, Lung, and Blood Institute (NHLBI), the major stumbling block of existing techniques is that the immune system in the animal receiving the organ tends to reject the transplant.

"We are still learning about new immunological hurdles and have to overcome these barriers in non-human transplant models," Mohiuddin said.

To study these immunological issues, scientists have studied xenotransplantation across several animal combinations, including the insertion of hamster organs into rats, and later into mice, as well as the transplantation of organs from pigs to baboons.

In a recent paper published in the esteemed journal PLoS Medicine, Mohiuddin cites a study in which insulin-producing cells, called islets, from pigs were transplanted into monkeys with diabetes. This led to the complete reversal of diabetes for over 100 days, researchers said.

However, suppressing immunological issues in the pig-to-monkey studies involved giving the monkeys drugs called immunosuppressants in doses that would be too large to be administered in humans. To overcome the need for overly large amounts of immunosuppressants, Mohiuddin suggests organs be farmed from pigs that are genetically modified to be more compatible with humans.

"Taking out some molecules which are immunogenic to humans and putting in human molecules [in the pig] will make the pig organ more compatible to humans," he said. "This allows us to use safer immunosuppression methods, which are now routinely used in allotransplantation [organ transplantation from human to human]."

Pigs were chosen as potential donors for their organ size, which is said to be comparable to human organs, their short breeding cycle and large litter size, and our ability to genetically manipulate their immune system, Mohiuddin explained.

While there are still some hurdles between current research and the potential use of pigs in human organ donation, such as the objections of animal rights proponents and concerns to do with the transmission of viruses across species, Mohiuddin believes there is a strong case for further research into xenotransplantation.

"In [the] United States alone there are more than 90,000 patients waiting for organ transplantation and only 25,000 transplants were performed during last year," he said. "Most of these patients will die waiting for the organs."

"Xenotransplantation has the potential to save many lives," he said.


Monday, 26 March 2007

Subconcious tactics of penalty box soccer

Scientists at Hong Kong University have come up with a theory that might prove extremely useful for football players around the world. Had Mark Schwarzer known in the fateful World Cup match against Italy last year what these Hong Kong scientists know today, Australian soccer fans might still be cheering.

As it turns out, a small tweak in where the goal keeper is positioned in the goal can make a player send the ball in a particular direction. By just standing a couple of centimetres to the right or left instead of in the middle of the goal, the goalie might thus be able to subconsciously convince the player to kick the ball into his or her path.

Rich Masters, assistant director of research and associate professor at the Institute of Human Performance at the University of Hong Kong, is one of the researchers behind the report. He became a football fan after spending some time in England.

"I studied for my Ph.D. in England and spent 14 years there. Gradually soccer just seeped into my blood. So I love to watch it, but play badly," he said in an interview.

Masters is an experimental psychologist with further interest in implicit knowledge, which he explained as such: "If something is implicit, it influences your behaviour without your knowledge. The penalty-taking study was a 'what-if' moment."

Football players and fans have long suspected the keeper´s position in the goal is important, and the article published by Masters and his colleagues John van der Kamp and Robin Jackson in the U.S. journal Psychological Science proves these speculations right. By standing six to ten centimetres off the centre of the goal - a displacement the penalty taking player is unlikely to notice - the chances are ten percent higher the player will send it towards the wider space.

Many fans loathe the idea of a game being decided on penalties, and it has been a long running debate both in England and internationally as to what extent this should be allowed to happen. The BBC recently reported on a decision by the English Football Association (FA) that stated that replay matches are still to decide who advances in the domestic FA-cup, instead of penalties as suggested by several managers.

Masters believes this kind of research can be helpful both for other parts of the game and for other sports, also here in Australia. "Recently I have been involved with both your Australian Institute of Sport and the New Zealand Academy of Sport because of the relevance of implicit motor learning to sport."

Perhaps these findings might help change the scene for penalty takers, so that the keeper is at less of a disadvantage, since today only 18 percent of penalty shots are saved.

One can only hope that the next time Francesco Totti rocks up against the Socceroos at the penalty spot in a vital World Cup game, he has not heard about this report.

Reidar von Hirsch is a soccer enthusiast and freelance journalist in Sydney, Australia.


Friday, 23 March 2007

Prepare your body clock for daylight savings

The end of daylight savings time may come with an extra hour on Australian clocks this Sunday, but it won’t necessarily mean more sleep, researchers say.

In fact, according to sleep researcher Sarah Blunden, most people will probably wake up at our body’s usual time, regardless of what the clock says.

“When we set our clocks forward or backward for daylight saving, we also have to re-set our body clocks,” said Blunden, of the University of South Australia’s Centre for Sleep Research. “It’s important to realize that we can’t change our body clock as fast as the clock on the wall.”

To assist in recalibrating one’s body clock, Blunden suggests some exposure to sunlight in the mornings. Light suppresses the sleep-regulating hormone, melatonin, she explained, and the more this melatonin is suppressed in the morning, the more readily it will rise when it is needed in the evening.

Children are expected to find it especially difficult to re-set their body clocks. Blunden said it can take up to a week to get children back on track, and recommends that parents adjust their children’s sleeping and waking schedules gradually, at about 10 to 15 minutes each day.

“This gradual adjustment works really well for most kids and is much better than forcing a child who isn’t sleepy to go to sleep just because the clock says they should," she said.

Parents should also encourage their children to engage in physical activity to burn any excess energy, while being mindful of their exposure to sunlight with minimal exposure in the evenings and maximum exposure in the mornings, Blunden said.

More information is available from the University of South Australia’s press release.


Thursday, 22 March 2007

Metalheads not boneheads

A recent psychological study has drawn links between heavy metal music and gifted youths with low self esteem.

Researchers surveyed 1,057 students aged between 11 and 18 years old to find out about their families, school attitudes, hobbies and media preferences. The students were also asked to rank favoured genres of music.

Rock was found to be the most popular form of music, followed closely by pop. But there were also differences between the type of music the young people liked and their attitudes – with those who liked heavy metal having lower self-esteem and ideas about themselves.

Engineers by day, metal aficionados by night: The Banned Substances - CSE Revue 2006
Further interviews were conducted with 19 gifted students to find out their views on heavy metal. These students said they did not consider themselves to be ‘metalheads’ but identified with specific aspects of this youth culture.

They spoke specifically about using heavy metal for catharsis, literally using the loud and often aggressive music to jump out frustrations and anger. Although the more ardent fans stated that ‘there’s metal out there for every occasion’, many also stated they listen to the music when they are in a bad mood.

Stuart Cadwallader, who conducted the study with professor Jim Campbell of the National Academy for Gifted and Talented Youth at the University of Warwick, speculated that gifted students who feel the pressure of their ability could be using heavy metal music to get rid of negative emotions.

“Perhaps the pressures associated with being gifted and talented can be temporarily forgotten with the aid of music,” he said. “As one student suggests, perhaps gifted people may experience more pressure than their peers and they use the music to purge this negativity.”

More information is available from the University of Warwick's press release.


Wednesday, 21 March 2007

Crikey! Jurassic croc discovered

An ancient sea-going crocodile from the Jurassic era has been discovered in the rocks of a mountain range in the U.S.

Fossilised remains were found imbedded in Jurassic rock in the Blue Mountains in eastern Oregon. About 50% of a 6- to 8- foot reptile was recovered, including long, needlepoint teeth.

The reptile is believed to have been a crocodile-like creature, except that it had a fish tail. It is believed to be from the species Thalottosucia, which is a predator that would have been common around much of the world about 142 to 208 million years ago.

An artist's illustration of what the Jurassic-age crocodile may have looked like in the water - John Hughes

Fossils similar to the Oregon crocodile appear today in many areas around South China, according to University of Oregon geologist William Orr, who also advises the North American Research Group (NARG) that made the discovery.

Orr expects the reptile to have lived in a tropical costal environment somewhere in the western Pacific, probably in area from Japan to East Timor. The remains in Oregon are believed to have migrated eastward in rock by continental drift.

Based on locations where fossils have been found, scientists have theorized that Thalattosuchians may have moved from semi-aquatic freshwater reptiles into fully ocean forms.

The reptiles' short stubby legs would have allowed them to move about land, where they may have laid eggs. But also, the creatures may have had webbed feet, which, in combination with the fish-like tail, would have made them rapid swimmers, allowing them to hunt along the surface of aquatic environments, scientists have theorized.

More information is available from the University of Oregon’s press release.


Tuesday, 20 March 2007

Climate change: a political hot potato

Climate change certainly is the hot topic of recent times, with enviro-friendly doomsayers, businesses and politicians making headlines across the globe.

Australian politicians this month took up a challenge set by studies in the UK and Australia, aiming to reduce greenhouse emissions by 60 percent before the year 2050. With the 2007 federal elections on the horizon, plans for meeting the greenhouse target seem to be on every party’s agenda, with solutions ranging from more effective coal-fired electricity to carbon pricing, nuclear power, better public transport, and investment in more research and development.

Meanwhile, in the U.S., the Bush administration has been charged with interfering with climate science to downplay the significance of global warming. Political appointees are being accused of editing scientific reports to emphasise scientific uncertainty and even trying to silence scientists in some cases.

Elsewhere, a debate rages on about whether global warming even exists. A recent paper by physicist Bjarne Andresen of the Niels Bohr Institute in Denmark asserts that the concept of a ‘global temperature’ is a statistical impossibility, thereby claiming that the entire debate surrounding global warming is more a political than scientific gesture.


Monday, 19 March 2007

Mouth-to-mouth resuscitation could do more harm than good

Skip mouth-to-mouth in emergency first aid; a new study has found that patients are twice as likely to survive a heart attack outside a hospital setting if bystanders perform chest-compression-only resuscitation instead of traditional CPR (cardiopulmonary resuscitation) with mouth-to-mouth breathing.

The study analysed the outcomes of 4,068 cases of resuscitation attempts performed by laypeople on adults who had collapsed from cardiac arrest. The observational study was based in the Kanto area in Japan, and is said to be is the first large-scale account comparing the survival rates of out-of-hospital cardiac arrest patients who were treated either with or without mouth-to-mouth ventilations by bystanders at the scene.

According to the study, which was led by Gordon A Ewy, director of the University of Arizona's Sarver Heart Center, mouth-to-mouth breathing takes too much time away from chest compressions, which have to be continuous to improve the chance of survival.

"We have found that the survival rate is higher even when the blood has less oxygen content, but is moved through the body by continuous chest compressions, than when the blood contains a lot of oxygen but is not circulated well because chest compressions are interrupted for mouth-to-mouth ventilations," Ewy said.

Poolside instructions for performing CPR
Ewy notes that eliminating the need for mouth-to-mouth ventilation not only is more effective, but also should dramatically increase the incidence of bystander-initiated resuscitation efforts, as studies have found that a majority of people currently are deterred from performing mouth-to-mouth on a stranger, partly out of fear of contracting diseases.

The study was published on March 17 in The Lancet. More information is available from the University of Arizona's press release.


Sunday, 18 March 2007

SciNet News launches!

SciNet News is published by Liz Tay, a physicist turned journalist at the University of Technology, Sydney.

Operating on the premise that science is fun (really!), SciNet News encompasses topics ranging from the asexuality of amoeba to the zeroth law of thermodynamics.

Ideas and contributions are always welcome. Contact scinetnews AT liztay DOT net.