Kathmandu was a geological time bomb

[Credit: Cosmos]

[Credit: Cosmos]

The 7.9 magnitude earthquake that hit Nepal and north India today, causing at least 1,500 casualties and widespread damage in Kathmandu, with the death toll rising all the time, was only too predictable as Cosmos reported in July last year - see Kathmandu's earthquake nightmare.

As Kate Ravilious wrote then

Earthquakes are a fact of life in Nepal. India is slamming into Asia at a rate of four centimetres a year and the strain that accumulates in the tectonic plates periodically releases itself in the form of earthquakes. This collision of continents has forced up the vast Himalayan mountain chain as the Indian plate slides beneath Asia. Tremors of magnitude 4 or 5 happen more than 10 times every year. But the real worry is the “great” earthquakes – magnitude 8 or more – that occur every century or so as strain in subsections of the fault up to 200 km long suddenly and violently releases.

Since the last great quake – a magnitude 8.4 –  in 1934 the population of Nepal has risen fivefold.

Geologists such as Paul Tapponnier have been working for years trying to understand the mechanics of the geology of the region, convinced that, if they can, they will better be able to predict major new earthquakes. But the geology is tricky.

As Kate wrote last year

Despite decades of searching no one had ever managed to find the rupture from the 1934 quake, leading many geologists to conclude that Nepal’s earthquakes are “blind” – the movement occurring deep underground but never quite slicing all the way up to the surface.
But Tapponnier was never convinced by that theory. “For me the idea of a ‘blind’ great earthquake is a paradox. We don’t find them in other parts of the world so the theory seems very strange.” It was a tantalising problem, the solution to which had potentially tremendous rewards for Nepal. “If a fault is blind then there is very little you can do except sit and wait for the earthquake – but if you know exactly where the earthquake tore the ground you can really start to prepare and reduce risk,” he says. In 2006, after a case of high-altitude pulmonary oedema made it dangerous for Tapponnier to continue working on the Tibetan plateau, he decided to descend to the plains of Nepal and try to solve the “blind” earthquake puzzle. 

He, and other scientists like him, warned that another major earthquake was overdue. In fact Tapponnier anticipated a major quake in exactly the location in which the current earthquake happened.

“The place I’m worried about now is central Nepal. I suspect that this central segment of thrust produced the great earthquake of the 14th century, which damaged much of Kathmandu. If that segment has a consistent recurrence time then the next great quake could be due there very soon,” he said.


Stem-cell therapy points to treatment of breast cancer metastases

Dr Khalid Shah

Dr Khalid Shah

A new stem-cell-based therapy could eliminate metastatic cells from the brain that develop from lung, breast or skin cancers, researchers at  Harvard Stem Cell Institute (HSCI) says.

"Metastatic brain tumours - often from lung, breast or skin cancers - are the most commonly observed tumours within the brain and account for about 30% of advanced breast cancer metastases," says Khalid Shah, an HSCI Principal Faculty member who led the study.

"Our results are the first to provide insight into ways of targeting brain metastases with stem-cell-directed molecules that specifically induce the death of tumor cells and then eliminating the therapeutic stem cells."

Shah's team first developed a mouse model that more closely mimics what is seen in patients. They found that injecting into the carotid artery breast cancer cells that express markers allowing them to enter the brain - cells labelled with bioluminescent and fluorescent markers to enable tracking by imaging technologies - resulted in the formation of many metastatic tumours throughout the brain, mimicking what is seen in advanced breast cancer patients. Current therapeutic options for such patients are limited, particularly when there are many metastases.

The scientists then engineered a population of neural stem cells to express a potent version of a gene called TRAIL, which codes for a molecule that activates cell-death-inducing receptors found only on the surface of cancer cells.

Previous research by Shah and his colleagues had shown that two types of stem cells are naturally attracted toward tumours in the brain.

Injecting the TRAIL-expressing stem cells into the carotid artery, a likely strategy for clinical application, led to significantly slower tumor growth and increased survival, compared with animals receiving unaltered stem cells or control injections.

Shah and his team are currently developing similar animal models of brain metastasis from lung cancers and from melanoma.

Vale the Sumatran rhino – now officially extinct in the wild in Sabah

The Sumatran rhino is the only  the smallest of the living rhinoceroses and the only Asian rhino with two horns. [Credit: WWF]

The Sumatran rhino is the only  the smallest of the living rhinoceroses and the only Asian rhino with two horns. [Credit: WWF]

There are no Sumatran rhinos left in the wild in the Malaysian state of Sabah, government minister Masidi Manjun says.

The Sumatran rhino once roamed as far away as the foothills of the Eastern Himalayas in Bhutan and eastern India, through Myanmar, Thailand, possibly to Vietnam and China, and south through the Malay Peninsula. 

In 2008, there were an estimated 50 rhinos in Sabah state, their last stand. By 2013 that was down to just 10 and now there are none.

"We are facing the prospect of our Sumatran rhinos going extinct in our lifetime,” Manjun told an environment seminar. 

Sabah's rhino is a distinct subspecies of Sumatran rhino, known as the Bornean rhino (Dicerorhinus sumatrensis harrissoni), and it looks increasingly possible that the Bornean rhino may only be represented by three surviving individuals, all of which are held in fenced, natural conditions at the Borneo Rhinoceros Sanctuary in Sabah. These include one male, Tam, and two females, Iman and Puntung. 
"If numbers of baby Sumatran rhinos can quickly be boosted in the coming few years, there is still hope to save the species from extinction," said John Payne, the Executive Director of the Borneo Rhino Alliance and one of the world's top experts on the species. "The only way now to achieve that is to use in vitro fertilization to produce the embryos and to have a few fertile females in well-managed fenced facilities, under excellent care, as the surrogate mothers." 

Vanishing habitat is the main culprit. Borneo was once covered almost completely in rainforest. Today its remnants are badly degraded by logging that began in the 1960s. More than 80% of Borneo's forests were removed, the timber sold overseas, mainly to the US and Japan.

The animals that survived that devastation then had to contend with widespread poaching.

Why do mosquitoes bite some people and leave others alone?

Dengue fever, Chikungunya virus and Zika virus are spread by the bite of an infected Aedes mosquito. [Credit: Universal History Archive/UIG via Getty images]

Dengue fever, Chikungunya virus and Zika virus are spread by the bite of an infected Aedes mosquito. [Credit: Universal History Archive/UIG via Getty images]

It could be in your genes, researchers say.

"Female mosquitoes display preferences for certain individuals over others, which is determined by differences in volatile chemicals produced by the human body and detected by mosquitoes," researchers at the London School of Hygiene and Tropical Medicine write.

"Body odour can be controlled genetically but the existence of a genetic basis for differential attraction to insects has never been formally demonstrated."

Their study investigated heritability of attractiveness to mosquitoes by evaluating the response of Aedes aegypti – the mosquito that can spread dengue fever, chikungunya, yellow fever viruses, and other diseases – to odours from the hands of identical and non-identical twins.

"Volatiles from individuals in an identical twin pair showed a high correlation in attractiveness to mosquitoes, while non-identical twin pairs showed a significantly lower correlation," the study says.

The scientists are still not entirely sure how this works, and say further research is needed to understand the specific genetic mechanisms that might be at play.

"In the future, we may even be able to take a pill which will enhance the production of natural repellents by the body and ultimately replace skin lotions," study author James Logan, a medical entomologist, said.

Could nuclear waste power our way to the stars?

[Credit: iStock]

[Credit: iStock]

The European Space Agency thinks it might. It has funded a program to produce americium-241 – the end product of the decay of plutonium isotopes found in the fuel of civil nuclear reactors.

Tim Tinsley, of the National Nuclear Laboratory in the UK, explains why this is an important development.

All spacecraft share the same power source at their hearts, he says, that provides the heat and power essential for them to survive and operate in the cold, dark vacuum of space.

Each derives its power from a few kilograms of red-hot plutonium-238. Without it, the spacecraft would not survive. Solar energy is too weak. The heat from the plutonium is able to keep essential systems warm and to also be converted to electricity using the thermoelectric Seebeck effect. With a half-life of 87.7 years, the plutonium has the potential to provide heat and electricity for well over a century.

But making plutonium-238 is expensive and difficult and stocks are running out.

You need a reactor with the right neutron flux and a supply of neptunium-237 feedstock to produce the plutonium. You also need a small nuclear reprocessing plant to separate the plutonium chemically from the highly radioactive fuel. Over the years, plutonium-238 has been produced by a number of countries including the USA, Russia, and the UK. Historically, some material has even been used to provide the electrical power in heart pacemakers.
In the case of plutonium for space applications, stocks of the material are now running low. The USA is restarting production, but the current stocks and production rate in the near term are unlikely to be high enough to support the broad range of space missions that the US science community might wish to target. 

But americium-241 could be a good alternative. To the nuclear industry it is a waste product that must be removed before plutonium can be reused in nuclear fuel. It is a potentially plentiful and reliable source of americium-241 that would otherwise be disposed of as waste.

But how would it perform in space?

Compared to plutonium-238, which has a half-life of 87.7 years and heat output of 0.4 watts per gram, americium-241 lasts longer with a half-life of 432 years but has a lower heat output of 0.1 watts per gram. The longer half-life means that the heat, and therefore the power output, reduce more slowly through time when compared to systems of equal power output. In addition, the higher isotopic purity of the americium-241 (greater than 99%) partially compensates for the reduced heat and power output. 

Graphene-based materials about to make Holograms a reality

[Credit: iStock]

[Credit: iStock]

Min Gu, Swinburne University of Technology and Xiangping Li, Swinburne University of Technology explain how 3D imagery could move from science fiction to reality in only a few years – and all thanks to the new wonder-material. Read The Myriad uses of amazing graphene.

Three dimensional holographic images and floating displays outside a screen have long been a favourite of science fiction movies such as the rescue message carried by R2-D2 in Star Wars.

The success of James Cameron’s 3D movie Avatar caused a tremendous worldwide interest in flexible, high-definition and floating display devices.

In fact, the dream of optically displaying a 3D object has been constantly driving the revolution of display technologies over the past decade.

At the moment most 3D imagery is only seen with the aid of special glasses. But the revenue generated by this 3D technology market in 2013 exceeded US$93.21 billion (almost double the global solar market), and is expected to grow up to US$279.27 billion by 2018.

High tech screens

The research efforts in nanotechnology have significantly advanced development of display devices. Graphene, an atomic layer of carbon material that won scientists Andre Geim and Konstantin Novoselov the 2010 Nobel Prize in Physics, has emerged as a key component for flexible and wearable displaying devices.

Owing to its fascinating electronic and optical properties, and high mechanical strength, graphene has been mainly used as touch screens in wearable devices such as mobiles.

This technical advance has enabled devices such as smart watches, fitness bands and smart headsets to transition from science fiction into reality, even though the display is still 2D flat.

But wearable displaying devices, in particular devices with a floating display, will remain one of the most significant trends in the industry, which is projected to double every two years and exceed US$12 billion in the year of 2018.

A 3D image with no glasses

In a paper, published today in Nature Communications, we show how our technology realises wide viewing-angle and full-color floating 3D display in graphene based materials. Ultimately this will help to transform wearable displaying devices into floating 3D displays.

A graphene enabled floating display is based on the principle of holography invented by Dennis Gabor, who was awarded the Nobel Prize in Physics in 1971. The idea of optical holography provides a revolutionary method for recording and displaying both 3D amplitude and phase of an optical wave that comes from an object of interest.

The 3D hologram are only 1cm in size at the moment – but it’s a start. Xiangping Li, Author provided

The physical realisation of high definition and wide viewing angle holographic 3D displays relies on the generation of a digital holographic screen which is composed of many small pixels.

These pixels are used to bend light carrying the information for display. The angle of bending is measured by the refractive index of the screen material – according to the holographic correlation.

The smaller the refractive index pixels, the larger the bending angle once the beam passes through the hologram. This nanometer size of pixels is of great significance for the reconstructed 3D object to be vividly viewed in a wide angle.

The process is complex but the key physical step is to control the heating of photoreduction of graphene oxides, derivatives of graphene with analogous physical structures but presence of additional oxygen groups.

Through a photoreduction process, without involving any temperature increment, graphene oxides can be reduced toward graphene by absorbing a single femtosecond pulsed laser beam.

During the photoreduction, a change in the refractive index can be created. Through such a photoreduction we are able to create holographically-correlated refractive index pixel at the nanometer scale.

Our technique enables the reconstructed floating 3D object to be vividly and naturally viewed in a wide angle up to 52 degrees.

This result corresponds to an improvement in viewing angles by one-order-of-magnitude compared with the current available 3D holographic displays based on liquid crystal phase modulators, limited to a few degrees.

In addition, the constant refractive index change over the visible spectra in reduced graphene oxides enables full-colour 3D display.

Starting small

At this moment, the demonstrated graphene 3D display can only allow images up to 1cm. But there is no limitation for the up scalability of this technique.

Owing to the excellent mechanical strength of graphene based materials, our technique can help to transit graphene-enabled wearable displaying devices from 2D into floating 3D displays.

It is projected that graphene 3D display at tens of centimetre scale, perfect for the wearable displaying devices, will be available within five years.

This new generation floating 3D display technology also has potential applications for military devices, entertainment, remote education and medical diagnosis.

The demonstrated principle would have potential impacts on the development of versatile holographic components and underpin the soaring development of holographic anti-counterfeit tags, security labels, identification code and so on.

The Conversation

This article was originally published on The Conversation. Read the original article.

Biometric security - 'Once your fingerprint is stolen it's gone forever'

[Credit: iStock]

[Credit: iStock]

Biometric technology – the use of fingerprints, iris scans or voice recognition for user identification – is seen as a more secure option that passwords. But can it really beat the hackers? 

Not always, reports Aarti Shahani, from a security conference in San Francisco.

Hackers have already made dummy fingerprints — using pictures of people's hands available online — to swipe into the iPhone 6 scanner, he says.

And that may be worse than a stolen password, according to David Cowan, whose firm Bessemer Venture Partners has invested $100 million in digital security companies – but not in biometrics.

"Either a password or a biometric can be stolen," he says. "But only the password can be changed. Once your fingerprint is stolen, it's stolen forever, and you're stuck."




Changing climate forces rethink of Aussie farming timetable

Declining autumn rains have hit yields of Aussie winter wheat. [Credit: iStock]

Declining autumn rains have hit yields of Aussie winter wheat. [Credit: iStock]

Anzac Day – 25 April – is not only the day when Australians honour their soldiers, for the country's wheat farmers it is also the the time to start sowing their winter crop. But, thanks to climate change, that may have to change, Australia's peak science research organisation CSIRO says.

..a team of our scientists in the Agriculture team are now recommending sowing earlier; any time from early April onward.
They’ve been trialling early sowing around southern Australia, and the results were staggering. By including early sown wheat in cropping programs, yield was increased by an average 13-47 per cent across all regions.

The CSIRO says that rainfall is critical for the establishment of fast growing wheat varieties and, with the changing climate, autumn rains have been declining. By Anzac Day, the optimal conditions may have passed.

But sowing earlier could cause a whole new set of problems. By shifting sowing earlier, it would mean the fast-growing wheat flowers just as frosts begin to hit. The CSIRO suggests combining staggered sowing from earlier in April and mixing mid- to fast maturing strains.

The paper on the tricky timing to optimise yields can be found here.

NASA gathers experts to search for life beyond the solar system

The search for life beyond our solar system requires unprecedented cooperation across scientific disciplines, says NASA. [Credit: NASA]

The search for life beyond our solar system requires unprecedented cooperation across scientific disciplines, says NASA. [Credit: NASA]

NASA is bringing together experts from all scientific fields in an initiative dedicated to the search for life on planets outside our solar system.  

“This interdisciplinary endeavor connects top research teams and provides a synthesized approach in the search for planets with the greatest potential for signs of life,” says Jim Green, NASA’s Director of Planetary Science. “The hunt for exoplanets is not only a priority for astronomers, it’s of keen interest to planetary and climate scientists as well.”

The first exoplanet around a star like our sun was only discovered in 1995, but Kepler space telescope, launched six years ago, has identified more than 1,000.

The new initiative – the Nexus for Exoplanet System Science, or “NExSS” – hopes to better understand the various components of an exoplanet, as well as how the planet stars and neighbour planets interact to support life.

NExSS will tap into the collective expertise from each of the science communities supported by NASA’s Science Mission Directorate:
Earth scientists develop a systems science approach by studying our home planet.
Planetary scientists apply systems science to a wide variety of worlds within our solar system.
Heliophysicists add another layer to this systems science approach, looking in detail at how the Sun interacts with orbiting planets.
Astrophysicists provide data on the exoplanets and host stars for the application of this systems science framework.

Meanwhile, there's bad news for those who hoped the Tau Ceti system could be home to an alternate Earth. It seems not.

Tau Ceti is a star in the constellation Cetus that is spectrally similar to the Sun. It is also the second closest star to the Sun, which has made it a popular setting for science fiction writers since at least 1949 when L. Sprague de Camp wrote The Queen of Zamba.  

Dr. Durand Durand – inventor of the Positronic Ray in the 1968 movie Barbarella – came from a planet in the Tau Ceti system and planets from there feature in several Star Trek episodes as well as the movie Star Trek II: The Wrath of Khan.

But, as phys.org reports, Arizona State University researchers say it is looking less probable that life like ours will be found there.

Since December 2012 Tau Ceti has become even more appealing, thanks to evidence of possibly five planets orbiting it, with two of these - Tau Ceti e and f - potentially residing in the habitable zone.
Using the chemical composition of Tau Ceti, the ASU team modeled the star's evolution and calculated its habitable zone. Although their data confirms that two planets (e and f) may be in the habitable zone it doesn't mean life flourishes or even exists there.
"Planet e is in the habitable zone only if we make very generous assumptions. Planet f initially looks more promising, but modeling the evolution of the star makes it seem probable that it has only moved into the habitable zone recently as Tau Ceti has gotten more luminous over the course of its life," explains astrophysicist Michael Pagano.

Thoughts on the power bill of the third little pig

Illustration by British artist Leonard Leslie Brooke about 1904.

Illustration by British artist Leonard Leslie Brooke about 1904.

Physicist Marcus Wilson from the University of Waikato in New Zealand takes issue with the children's fairy story The Three Little Pigs.

Not being an engineer, he has little to say about the structural integrity of the various houses or the likelihood of a big bad wolf being able to blow them down.

But he is concerned about how the third little pig managed to heat a wolf-sized pot of water to a high enough temperature that would scald the animal – and that all in a minute... 

One litre of water takes 4200 joules of energy to raise its temperature by 1 degree C. That's called the 'specific heat capacity'. To raise 100 litres by 75 degrees, we therefore need 4200 times 100 times 75 = 31 500 000 joules. This happens in sixty seconds - thats about half a million joules per second. What does that mean? One joule per second is one watt of power. So here we have about 500 kW of power - a kW (kilowatt) being a thousand watts.  

Bedtime is obviously an improving experience in the Wilson household...