Cassini gets a glimpse of Titan's sunlit seas

A near-infrared, colour mosaic from NASA's Cassini spacecraft shows the sun glinting off of Titan's north polar seas. Click to expand image. [Credit: NASA]

NASA's Cassini spacecraft has captured an image of bright sunlight reflecting off hydrocarbon seas on Saturn's large moon Titan.

The sunglint is in the south of Titan's largest sea, Kraken Mare, just north of an island archipelago separating two separate parts of the sea and is helping scientists get a better idea of Titan's terrain.

Titan's seas are mostly liquid methane and ethane. Cassini has found great fields of sand dunes near the moon's equator and lower latitudes, and lakes and seas near the poles, particularly in the north.

The southern portion of Kraken Mare has what NASA has described as a "bathtub ring" – a bright margin of evaporate deposits indicating that the sea was larger at some point in the past and has become smaller due to evaporation. The deposits are material left behind after the methane and ethane liquid evaporates, in the way a saline crust is left on a salt flat.

A labyrinth of channels connect Kraken Mare to another large sea, Ligeia Mare, which is partially covered in its northern reaches by a bright, arrow-shaped complex of clouds made of liquid methane droplets that could be actively refilling the lakes with rainfall.

The view was acquired during Cassini's 21 August 2014. The image above contains real colour information, although it is not the natural colour the human eye would see. The unaided human eye would see little but haze.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. More information is available on the NASA website.

Graphene technology that could revolutionise light detection

Graphene, a single sheet of interconnected carbon atoms, has great potential and Monash University researchers may have found a new use for it. [Credit: iStock]

Graphene, a single sheet of interconnected carbon atoms, has great potential and Monash University researchers may have found a new use for it. [Credit: iStock]

We're always on the lookout for stories about practical applications of graphene. It's an amazing substance, obviously, but one which, for all the promise, has so far fallen short of real breakthrough applications.

So we were excited to catch up with work by a team of researchers at Monash University to create a light detector based on the material – a single sheet of interconnected carbon atoms. 

The detector has the potential to revolutionise chemical sensing and night vision technology as it can detect light over an unusually broad range of wavelengths, even terahertz waves that lie between infrared and microwave radiation, where sensitive light detection is most difficult. 

“We have demonstrated light detection from terahertz to near-infrared frequencies, a range about 100 times larger than the visible spectrum,” Professor Michael Fuhrer, of the School of Physics at Monash, said.

“Detection of infrared and terahertz light has numerous uses, from chemical analysis to night vision goggles, and body scanners used in airport security.”

Terahertz detection already exists, but technological applications are limited, as the detectors using current technology need to be kept extremely cold to maintain sensitivity. But, according to Fuhrer, the new detector works at room temperature, and is already as sensitive as any existing room-temperature detector technology in the terahertz range, but was also more than a million times faster. 

The key to it is the hot-electron photo thermoelectric effect of the grapheme lattice structure. Photoexcited carriers rapidly heat up due to strong electron-electron interactions, but lose energy to the lattice more slowly.

Fuhrer has written about his discovery here

One property of graphene that interested me was that bilayer graphene (two layers stacked one on another) has a bandgap — the basic property of a semiconductor — that can be tuned by applying an electric field to the material.
I teamed up with researchers at the University of Maryland to try to measure this bandgap using infrared light, since infrared photons have energies which are similar to bilayer graphene’s bandgap. When we measured the conductance of our bilayer graphene under infrared illumination, we found that it changed much more than we expected. 
In fact, the change in conductance in our graphene was greater than that of the commercial silicon photodetector we were using to measure the power of our infrared beam! For some reason, our graphene was an excellent photodetector. 
We knew enough about graphene to figure out what was happening. When the electrons in graphene absorb light, they heat up. In most materials, the electrons quickly lose energy to vibrations of the atoms, which we sense as heat. 
But in graphene this process of heat loss is very inefficient, which gives graphene its extraordinarily high electrical conductivity. What we realised is that bilayer graphene with a bandgap has a conductance that varies strongly with electron temperature, allowing us to read out the change in electron temperature caused by the light heating the electrons.

Fuhrer also discusses the problems of working out how best to use new materials such as graphene to make the most of their potential.

As a researcher working on new materials, I am constantly asked “what is it good for?” To answer this, the first thing we researchers often try is to imagine the new material as a replacement for an existing one in an existing technology. 

But he says there is a better approach.

...a better question — though much more difficult to answer — is to ask what a new material might enable us to do that no other material has before. The answers to that question don’t always come immediately, and sometimes they come serendipitously. 

 

 

Why are there so few women economists?

Janet L. Yellen, the chair of the US Federal Reserve, is the first woman to lead the central bank. She graduated from Brown University with a degree in Economics in 1967, when very few women enrolled. Things have improved but still only half the number of women as men read economics at university.

Janet L. Yellen, the chair of the US Federal Reserve, is the first woman to lead the central bank. She graduated from Brown University with a degree in Economics in 1967, when very few women enrolled. Things have improved but still only half the number of women as men read economics at university.

Scientists in the UK have confirmed what anecdotally we all knew – there are far fewer women economists than men.

Less than half the number of young women than men apply for economics on leaving school, which means there are fewer to take up jobs in think tanks, ministries, central banks and international organisations, like the IMF and the World Bank.

"This underrepresentation of women economics degrees could have major implications in policy making," says lead author of the study Dr Mirco Tonin.

It looks like the problem starts earlier, at school, where almost half the number of girls study maths until their final year as boys.

The Southampton University study found that only 10% of females enrol at university with an A level in maths, compared to 19% of males.

Women account for just 27% of economics students, despite them making up 57% of the undergraduate population in UK universities.

It may be having a dramatic effect on the direction our world is taking. Previous studies have shown women favour different policy decisions to men, with men more likely to want to cut costs associated with government interventions in the labour market, for example.

The researchers lack of women with degrees in economics could also be contributing to the gender pay gap, since economics graduates tend to receive relatively high average earnings.

The researchers took a a random sample of administrative data covering all university applications in 2008. They say there was no discrimination against females in the university application process and, once they've applied, females are as likely as males to receive an offer of a place on an economics course.

But the young women who do apply to study economics are better prepared than the boys. They tend to have a stronger maths background and better grades.

The study, is published in the CESifo Economic Studies journal (pdf). It highlights other studies which suggest the gender gap in mathematics disappears in more gender equal societies.

"This suggests that cultural rather than biological factors are behind the gender gap and that a positive loop may develop, with more equality leading to better education achievement by girls, leading in turn to more equality," says co-author Professor Jackline Wahba.

"We believe that enrolment in Economics may be an important channel in this loop. If more girls become proficient in Maths, more are likely to enrol into an Economics degree and, in turn, more are likely to access positions of influence in policy making, from where they can promote a more gender equal society."

So where are we with the search for an Ebola vaccine?

An article by Paul Howard, the director of the Manhattan Institute’s Center for Medical Progress, gives a useful update to our overview of the fight against Ebola. Howard looks specifically at the progress towards a vaccine, which he says is the best hope of stopping it – and our best hope of that lies with the US. As Howard writes: "If Uncle Sam doesn’t shell out the money to help develop and then buy an Ebola vaccine, no one else will."

If the virus continues on its current trajectory, our best hope to stop it lies in the development of a successful vaccine. Vaccines against Ebola have been tested on macaque monkeys since the 1990s. After 9/11, the U.S. began investing heavily in Ebola research, concerned about the virus’s potential as a bioweapon. Various pieces of legislation, including Project BioShield in 2004 (reauthorized in 2013), and billions of federal dollars have been focused on financing the development and stockpiling of “medical countermeasures” against likely agents of bioterrorism—including hemorrhagic fevers like Ebola and Marburg.

The good news is we might have a vaccine by next year.

Johnson & Johnson is partnering with a Danish company to produce its own vaccine. Unlike GSK’s vaccine, J&J’s prototype requires two vaccinations, but may provide longer-lasting immunity. Even more promising, J&J has suggested that it could have 250,000 doses of its vaccine produced in 2015, a massive accomplishment (if it works). Pfizer and other companies have stepped up to partner with those firms to share production facilities.

The bad news is that it might not be enough to stop the disease's spread in many places.

Health authorities worry they might not be able to distribute an effective vaccine widely enough to halt Ebola’s spread in the most severely stricken regions. Only time will tell.

Meanwhile, University of Western Australia medical microbiologist Tim Inglis, has called on Australia to stop panicking about the disease and lend a hand.

He and his team are preparing to test a mobile lab in the tropical conditions of northern Western Australia in the coming weeks and hopes to be working in West Africa by the end of the year.

He argues in Nature that the best defence for developed countries is to act now rather than risk waiting when the crisis could be far worse.

The threat posed by a few imported cases of Ebola is low: Australia has the procedures, resources and facilities here to minimize the risk of secondary transmission. And other developed countries are willing to accept that risk because they understand the crucial and urgent need to tackle the outbreak in Africa. Mathematical models predict that transmission will continue for many months, even if the rate of expansion levels out soon. The large number of infections clearly increases the probability of exports and that the virus's genome will continue to mutate. The real issue is that the threat to Australia, the United States and other developed countries will be much higher in six months. The best defence is to act now and in Africa.

Most Australian scientists agree. As Dr Jennifer Todd is a Senior Lecturer in the School of Health & Society at the University of Wollongong says:

 "...containing the virus is the only way we will keep it from jumping to other countries via wild secondary cases, or mutating virus. We must move not at bureaucratic speed, but at viral speed if we have any hope of staying ahead of this pathogen."

But Professor Nikolai Petrovsky, the Director of Endocrinology at the Flinders University School of Medicine and the Executive Director of biotech firm Vaxine is not quite on the same page. He wonders if there is value in studying the disease on the frontline and just what Inglis intends to do there.

"I am not entirely sure how basing more 'scientists' at the front line is necessarily going to help, and certainly supporting such a team is going to consume local resources that might be directed elsewhere, but partly this is because the article doesn't explain what exactly Tim proposes to do in his mobile laboratory that is likely to impact on the overall Ebola crisis. If we knew what exactly was intended and the object of the exercise, then the risk–benefit equation may be more clearly in favour of benefit. Without such an explanation this proposal is likely to be considered by many foolhardy. Nevertheless it is a brave step into an unknown world, and definitely a good topic for discussion.

 

Hubble spies the ghost light of long-dead galaxies

The massive galaxy cluster Abell 2744, nicknamed Pandora's Cluster, where the starlight from the cluster has been coloured blue. The galaxies that are not colored blue lie either in the foreground or background and are not part of the cluster. Click to expand image. [Credit: NASA, ESA, M. Montes (IAC), and J. Lotz, M. Mountain, A. Koekemoer, and the HFF Team]

NASA’s Hubble Space Telescope has picked up the faint, ghostly glow of stars ejected from ancient galaxies that were gravitationally ripped apart several billion years ago.

As many as six galaxies were torn apart inside Abell 2744, an immense collection of nearly 500 galaxies nicknamed “Pandora’s Cluster", some 4 billion light-years away. The scattered stars are no longer bound to any one galaxy, and drift between galaxies in the cluster.

Hubble astronomers believe the six galaxies were torn apart over a period of 6 billion years.

Computer modeling of the gravitational dynamics among galaxies in a cluster suggests that galaxies as big as our Milky Way are the likely candidates as the source of the stars.

The doomed galaxies might have been destroyed as they plunged through the centre of the galaxy cluster where gravitational tidal forces are strongest.

Astronomers have long hypothesised that the light from scattered stars should be detectable after such galaxies are disassembled. However, the predicted “intracluster” glow of stars is very faint and was therefore a challenge to identify.

“The Hubble data revealing the ghost light are important steps forward in understanding the evolution of galaxy clusters,” said Ignacio Trujillo of the Instituto de Astrofisica de Canarias (IAC), La Laguna, Tenerife, Spain, one of the researchers involved in the study. “It is also amazingly beautiful in that we found the telltale glow by utilizing Hubble’s unique capabilities.”

The phantom stars are rich in heavier elements such as oxygen, carbon, and nitrogen. This means the scattered stars must be second- or third-generation stars that were enriched with the elements forged in the hearts of the universe’s first-generation stars.

With the mass of 4 trillion suns, Abell 2744 is a target in the Frontier Fields three-year program looking at select massive galaxy clusters to help astronomers probe the remote universe.

Scientists build a stomach from stem cells

In a world first, scientists in Cincinatti have used stem cells to create functional, three dimensional human stomach tissue in a laboratory. The project provides hope for the 10% of the world's population suffering from stomach diseases including peptic ulcers and cancer.

The researchers at the Cincinnati Children's Hospital Medical Center reported in Nature that they had used the miniature stomachs to study infection by H. pylori bacteria, a major cause of stomach disease. They are also studying some of the underpinnings of obesity related diabetes.

"Until this study, no one had generated gastric cells from human pluripotent stem cells," said Jim Wells, the team leader. "In addition, we discovered how to promote formation of three-dimensional gastric tissue with complex architecture and cellular composition."

This is important because differences between species in the embryonic development and architecture of the adult stomach make mouse models less than optimal for studying human stomach development and disease, Wells added.

The scientists first identified the steps involved in normal stomach formation during embryonic development. By manipulating these normal processes, the scientists were able to coax pluripotent stem cells toward becoming stomach. 

Brain activity is a clear giveaway to your political leanings

Brain activity can predict which side of the political fence we stand. [Credit: iStock]

Brain activity can predict which side of the political fence we stand. [Credit: iStock]

You can tell a person's political persuasion simply by how they react to a disgusting image, scientists have found.

Inspired by evidence that people's political affiliations are almost as heritable as their heights, Virginia Tech researcher P. Read Montague decided to try and work out how close the connections were.

Working on the assumption that political ideologies summarise many aspects of life, such as attitudes to sex, family, education, and personal autonomy, Montague and his team decided to see whether functional magnetic resonance images (fMRI) of the brain taken as people passively looked at a series of disgusting, pleasant, and neutral images was enough to give away their political leanings.

Sure enough, they found that disgusting images – especially the mutilated body of an animal  –generated neural responses that were highly predictive of political orientation.

“A single disgusting image was sufficient to predict each subject’s political orientation,” Montague says. “I haven’t seen such clean predictive results in any other functional imaging experiments in our lab or others.”

What is not clear from the study is exactly how or why liberal versus conservative brains differ from each other, but they clearly do, Montague says.

And that knowledge might help us work out how we can develop a less partisan political landscape.

“If we can begin to see that some ‘knee-jerk’ reactions to political issues may be simply that — reactions — then we might take the temperature down a bit in the current boiler of political discourse.”

Montague likened it to the inheritance of height.

“In the same sense that height is highly genetically specified, it’s also true that it’s not predetermined by genetics; nutrition, sleep, starvation, dramatic physical injury, and so on can serve to change one’s ultimate height. However, tall people have tall children, and this is a kind of starting point.”

The research is published in Current Biology.

Australian PM's science prize winners announced

The Australian Prime Ministers Prizes for Science have been announced. They will be presented tonight at a dinner in the Great Hall of Parliament House.

The winners are:

Sam Berkovic and Ingrid Scheffer

Sam Berkovic and Ingrid Scheffer

Sam Berkovic and Ingrid Scheffer, who have changed the way the world thinks about epilepsy. They will receive the $300,000 Prime Minister’s Prize for Science. Their discoveries of the links between epilepsy and genes have opened the way to better targeted research, diagnosis, management and treatment for many forms of epilepsy.

The winners are associated with the University of Melbourne, the Florey Institute of Neuroscience and Mental Health, and Austin Health.





Matthew Hill

Matthew Hill

Matthew Hill, who has created crystals that are set to transform industry. His metal-organic frameworks — the world’s most porous materials — can be used as efficient and long-lasting filters to clean up natural gas, water, pollution and can safely store hydrogen, carbon dioxide and other gases. Dr Hill from CSIRO will receive the $50,000 Malcolm McIntosh Prize for Physical Scientist of the Year.



Ryan Lister

Ryan Lister

Ryan Lister, who has mapped how our genes are turned on and off, revealing why a leaf cell is different to a root cell or a stem cell differs from a skin cell. He will receive the $50,000 Frank Fenner Prize for Life Scientist of the Year. Professor Lister’s work at the University of Western Australia has the potential to transform agriculture, regenerative medicine and our understanding of the workings of the brain.

 

 

Geoff McNamara

Geoff McNamara

Geoff McNamara, who has created a hot-house of science learning for all his students at Melrose High School in Canberra. Mr McNamara will receive the $50,000 Prime Minister’s Prize for Excellence in Science Teaching in Secondary Schools. From dinosaurs to galaxies, weather stations to genetics, his classes explore the impact of science in daily life. For higher-achieving science students he connects students with practicing scientists and real-world science investigations.


Brian Schiller

Brian Schiller

Brian Schiller, who has integrated play, science and languages at Seacliff Primary School in Adelaide. Mr Schiller will receive the $50,000 Prime Minister’s Prize for Excellence in Science Teaching in Primary Schools. He nurtures creativity in the classroom through student-initiated investigations, where the students bring the questions and Brian guides them in setting up investigations to get the answers. Then they communicate their work in conversation, writing, pictures, and even in Japanese.

Melbourne researchers hope for Alzheimer's blood test in three years

Professor Andrew Hill (third from left back row) and his team. [Credit: University of Melbourne]

Professor Andrew Hill (third from left back row) and his team. [Credit: University of Melbourne]

A simple blood test to diagnose early onset Alzheimer's disease could be as close as three years away, according to researchers at the University of Melbourne.

Professor Andrew Hill and his team looked at the gene-regulating molecules of microRNA in people with Alzheimer's disease and compared them with those who did not.

"The first part of the study we sequenced 50 people - 23 had Alzhimer's and 23 were controls and then there were another few that were in an in-between stage," Professor Hill told Australian television. He said his team could identify 16 out of 1,400 microRNA that had changed in Alzheimer's patients.

Early detection could lead to treatments that slows the onset of the crippling disease, he said. Hill's team will also now investigate whether microRNA was involved in the progress of the Alzheimer's.

"That's something that we haven't been able to show so far, we just are basically looking for a marker of Alzheimer's disease using a simple laboratory test that measures the number of these microRNAs in the blood samples," he said.

The work has taken three years so far and if the results are validated, a blood test could be rolled out in three to five years, Hill said.