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Haast's Eagle Was Big & Strong Enough to Prey on Humans

Haast's Eagle Was Big & Strong Enough to Prey on Humans | Amazing Science | Scoop.it

The strongest and biggest bird of prey that ever lived was the Haast’s Eagle (Harpagornis moorei) of New Zealand, and it became extinct around the 1400s soon after the Maori settled the South Island of New Zealand.

 

H. moorei was powerful enough to attack and prey on giant flightless birds, the moa, weighing 10 to 15 times their own body weight. Comparatively to its body size, the Haast’s Eagle’s wingspan was short, at about 9 feet. It’s believed that the raptor would swoop down at speeds of nearly 50 mph to attack the moa. It used its talons to kill them on the ground and didn’t carry off its prey.

 

It’s believed that the Haast’s Eagle and moa evolved due to island gigantism, a phenomenon in which animals isolated from other, more diverse populations, end up much larger than they would be on mainland. When the Maori first arrived in New Zealand, there were no land animals. Birds and reptiles evolved to fill up these empty ecological niches that would have been typically filled up by larger mammals.

 

Evolutionarily speaking, Haast’s Eagle took the place of the apex predator that hunted grazers, a space taken up by the moa species. When the Maori hunted the moa to extinction in the 1400s, barely a century after their arrival, there was no prey large enough to sustain the Haast’s Eagles, so they became extinct quickly. No evidence has been found that Haast’s Eagle preyed on humans, but researchers believe it was big and strong enough to do so.

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20,000+ FREE Online Science and Technology Lectures from Top Universities

20,000+ FREE Online Science and Technology Lectures from Top Universities | Amazing Science | Scoop.it

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Scientists observe the "forbidden" infrared spectrum of a charged molecule for the first time

Scientists observe the "forbidden" infrared spectrum of a charged molecule for the first time | Amazing Science | Scoop.it

Researchers at the University of Basel in Switzerland have succeeded in observing the "forbidden" infrared spectrum of a charged molecule for the first time. These extremely weak spectra offer perspectives for extremely precise measurements of molecular properties and may also contribute to the development of molecular clocks and quantum technology. The results were published in the scientific journal Nature Physics.

Spectroscopy, the study of the interaction between matter and light, is probably the most important method for investigating the properties of molecules. Molecules can only absorb light at well-defined wavelengths which correspond to the difference between two quantum-mechanical energy states. This is referred to as a spectroscopic transition. An analysis of the wavelengths and the intensity of the transitions provides information about the chemical structure and molecular motions, such as vibration or rotation.


In certain cases, however, the transition between two energy levels is not permitted. The transition is then called "forbidden". Nevertheless, this restriction is not categorical, meaning that forbidden transitions can still be observed with an extremely sensitive method of measurement. Although the corresponding spectra are extremely weak, they can be measured to an exceptionally accurate degree. They provide information on molecular properties with a level of precision not possible within allowed spectra.


In the present study, individual charged nitrogen molecules (ions) were generated in a well-defined molecular energy state. The ions were then implanted into a structure of ultra-cold, laser-cooled calcium ions – a Coulomb crystal – in an ultra-high vacuum chamber. The molecular ions were thus cooled to a few thousandths of a degree above absolute zero to localize in space. In this isolated, cold environment, the molecules could be investigated without perturbations over long periods of time. This enabled the researchers to excite and observe forbidden transitions in the infrared spectral domain using an intensive laser.

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High-energy gamma ray bursts have 100-times the energy output of a supernova

High-energy gamma ray bursts have 100-times the energy output of a supernova | Amazing Science | Scoop.it

In the 1960s a series of satellites were built as part of Project Vela.  Project Vela was intended to detect violations of the 1963 ban on above ground testing of nuclear weapons.  The Vela satellites were designed to detect bursts of gamma rays, which are high energy electromagnetic waves produced by radioactive decay.  If any nuclear weapon was detonated in space, the resulting radioactive decay would release a large amount of gamma rays which would be detected by the Vela satellites.

In 1967, two of the Vela probes detected a large spike of gamma rays.  But the signature of this spike was very different from those of a nuclear explosion.  Soon more gamma ray spikes were detected, and these likewise differed from the expected signature of a nuclear test.  Since the bursts were observed by multiple satellites, the Vela team was able to compare the arrival of the bursts between different satellites, and it soon became clear that the bursts had an extraterrestrial source.  Of course the Vela project was classified, so it wasn't until 1973 that the results were declassified and published in Astrophysical Journal.  It was only then that astronomers were made aware of these gamma ray bursts (GRBs).


We now know that GRBs are very common.  On average, about one gamma ray burst occurs every day.   They appear randomly in all directions of the sky, and this means they aren't produced in our galaxy.  If they were, then GRBs would mostly be found along the plane of the Milky Way.


Some gamma ray bursts (known as long bursts) can last more than two seconds.  These bursts have afterglow caused by gamma rays colliding with interstellar material near the event, causing the emission of light at other wavelengths.  This afterglow allows us to measure the redshift of these events, and what we find is that they are quite distant.  The closest observed gamma ray burst occurred at a distance of 100 million light years, and many occurred billions of light years away.


We aren't entirely sure what causes a gamma ray burst.  Because of their distance, and apparent brightness, they must be extraordinarily energetic, with about 100 times more energy than a supernova.  They may be caused by huge supernova explosions known as hypernova, or they may be caused by supernova explosions occur with a rotational axis pointing in our direction, causing a jet-like burst of energy.  Short burst GRBs, lasting less than 2 seconds, may be due to collisions between neutron stars.


Given the huge energy of GRBs, one might wonder if one could occur in our galaxy.  Given the average rate of GRBs and the huge distances at which they typically occur, the rate at which one happens in our galaxy is probably about once every 5 million years.

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Star of David: New star-shaped molecule of interlocking rings is the most complex of its kind ever created

Star of David: New star-shaped molecule of interlocking rings is the most complex of its kind ever created | Amazing Science | Scoop.it

Known as a 'Star of David' molecule, scientists have been trying to create one for over a quarter of a century and the team's findings are published in the 21 September 2014 issue of Nature Chemistry.


Consisting of two molecular triangles, entwined about each other three times into a hexagram, the structure's interlocked molecules are tiny – each triangle is 114 atoms in length around the perimeter. The molecular triangles are threaded around each other at the same time that the triangles are formed, by a process called 'self-assembly', similar to how the DNA double helix is formed in biology.


The molecule was created at The University of Manchester by PhD student Alex Stephens. Professor David Leigh, in Manchester's School of Chemistry, said: "It was a great day when Alex finally got it in the lab. In nature, biology already uses molecular chainmail to make the tough, light shells of certain viruses and now we are on the path towards being able to reproduce its remarkable properties.


"It's the next step on the road to man-made molecular chainmail, which could lead to the development of new materials which are light, flexible and very strong. Just as chainmail was a breakthrough over heavy suits of armour in medieval times, this could be a big step towards materials created using nanotechnology. I hope this will lead to many exciting developments in the future."

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Battling superbugs: New strategies for combating MRSA and other drug-resistant bacteria

Battling superbugs: New strategies for combating MRSA and other drug-resistant bacteria | Amazing Science | Scoop.it

In recent years, new strains of bacteria have emerged that resist even the most powerful antibiotics. Each year, these superbugs, including drug-resistant forms of tuberculosis and staphylococcus, infect more than 2 million people nationwide, and kill at least 23,000. Despite the urgent need for new treatments, scientists have discovered very few new classes of antibiotics in the past decade. 


MIT engineers have now turned a powerful new weapon on these superbugs. Using a gene-editing system that can disable any target gene, they have shown that they can selectively kill bacteria carrying harmful genes that confer antibiotic resistance or cause disease. 

Led by Timothy Lu, an associate professor of biological engineering and electrical engineering and computer science, the researchers described their findings in the Sept. 21 issue of Nature Biotechnology.


Last month, Lu’s lab reported a different approach to combating resistant bacteria by identifying combinations of genes that work together to make bacteria more susceptible to antibiotics.

Lu hopes that both technologies will lead to new drugs to help fight the growing crisis posed by drug-resistant bacteria.


“This is a pretty crucial moment when there are fewer and fewer new antibiotics available, but more and more antibiotic resistance evolving,” he says. “We’ve been interested in finding new ways to combat antibiotic resistance, and these papers offer two different strategies for doing that.”


Most antibiotics work by interfering with crucial functions such as cell division or protein synthesis. However, some bacteria, including the formidable MRSA (methicillin-resistant Staphylococcus aureus) and CRE (carbapenem-resistant Enterobacteriaceae) organisms, have evolved to become virtually untreatable with existing drugs.


In the new Nature Biotechnology study, graduate students Robert Citorik and Mark Mimee worked with Lu to target specific genes that allow bacteria to survive antibiotic treatment. The CRISPR genome-editing system presented the perfect strategy to go after those genes.


CRISPR, originally discovered by biologists studying the bacterial immune system, involves a set of proteins that bacteria use to defend themselves against bacteriophages (viruses that infect bacteria). One of these proteins, a DNA-cutting enzyme called Cas9, binds to short RNA guide strands that target specific sequences, telling Cas9 where to make its cuts.


Lu and colleagues decided to turn bacteria’s own weapons against them. They designed their RNA guide strands to target genes for antibiotic resistance, including the enzyme NDM-1, which allows bacteria to resist a broad range of beta-lactam antibiotics, including carbapenems. The genes encoding NDM-1 and other antibiotic resistance factors are usually carried on plasmids — circular strands of DNA separate from the bacterial genome — making it easier for them to spread through populations.


When the researchers turned the CRISPR system against NDM-1, they were able to specifically kill more than 99 percent of NDM-1-carrying bacteria, while antibiotics to which the bacteria were resistant did not induce any significant killing. They also successfully targeted another antibiotic resistance gene encoding SHV-18, a mutation in the bacterial chromosome providing resistance to quinolone antibiotics, and a virulence factor in enterohemorrhagic E. coli.


In addition, the researchers showed that the CRISPR system could be used to selectively remove specific bacteria from diverse bacterial communities based on their genetic signatures, thus opening up the potential for “microbiome editing” beyond antimicrobial applications.

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New LED-based lab-on-a-chip device screens for 170,000 different molecules in blood

New LED-based lab-on-a-chip device screens for 170,000 different molecules in blood | Amazing Science | Scoop.it

Ecole polytechnique fédérale de Lausanne (EPFL; Lausanne, Switzerland) researchers have developed a new light-emitting diode (LED)-based handheld device that is able to test a large number of proteins in our body all at once. Professor Hatice Altug and postoctoral fellow Arif Cetin from EPFL in collaboration with professor Aydogan Ozcan from UCLA (Los Angeles, CA) developed the compact and inexpensive "optical lab on a chip" to quickly analyze up to 170,000 different molecules in a blood sample--simultaneously identifying insulin levels, cancer and Alzheimer markers, or even certain viruses.


Instead of analyzing the biosample by looking at the spectral properties of the sensing platforms as has traditionally been the case, this new technique uses changes in the intensity of the light to do on-chip imaging, eliminating sometimes clunky spectrometers in the process.


Only 7.5 cm high and weighing 60 g, the device is able to detect viruses and single-layer proteins down to 3 nanometers thick. Detailed in a publication in Nature Light: Science & Application, the recipe is simple and contains few ingredients: an off-the-shelf CMOS chip, an LED, and a 10 square millimeter gold plate pierced with arrays of extremely small holes less than 200 nm wide.


Nanoholes on the gold substrates are compartmented into arrays of different sections, where each section functions as an independent sensor. Sensors are coated with special biofilms that are specifically attracting targeted proteins. Consequently, multiple different proteins in the biosamples could be captured at different places on the platform and monitored simultaneously. The LED light shines on the platform, passes through the nanoscale openings and its properties are recorded onto the CMOS chip. Since light going through the nanoscale holes changes its properties depending on the presence of biomolecules, it is possible to easily deduce the number of particles trapped on the sensors.

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The Sahara Is Millions of Years Older Than Thought

The Sahara Is Millions of Years Older Than Thought | Amazing Science | Scoop.it

The great desert was born some 7 million years ago, as remnants of a vast sea called Tethys closed up. The movement of tectonic plates that created the Mediterranean Sea and the Alps also sparked the drying of the Sahara some 7 million years ago, according to the latest computer simulations of Earth’s ancient climate.


Though North Africa is currently covered by the world’s largest non-polar desert, climate conditions in the region have not been constant there for the last several million years. Subtle changes in Earth’s tilt toward the sun periodically increase the amount of solar energy received by the Northern Hemisphere in summer, altering atmospheric currents and driving monsoon rains. North Africa also sees more precipitation when less of the planet’s water is locked up in ice. Such increases in moisture limit how far the Sahara can spread and can even spark times of a “green Sahara”, when the sparse desert is replaced by abundant lakes, plants and animals.


Before the great desert was born, North Africa had a moister, semiarid climate. A few lines of evidence, including ancient dune deposits found in Chad, had hinted that the arid Sahara may have existed at least 7 million years ago. But without a mechanism to explain how it emerged, few scientists thought that the desert we see today could really be that old. Instead, most scientists argue that the Sahara took shape just 2 to 3 million years ago. Terrestrial and marine evidence suggest that North Africa underwent a period of drying at that time, when the Northern Hemisphere started its most recent cycle of glaciation.


Now Zhongshi Zhang of the Bjerknes Centre for Climate Research in Bergen, Norway, and colleagues have run simulations of climate change in North Africa over the last 30 million years. Their simulations take into account changes in Earth’s orbital position, atmospheric chemistry and the ratio of land to ocean as driven by tectonic forces. The models shows that precipitation in North Africa declined by more than half about 7 million years ago, causing the region to dry out. But this effect could not be explained by changes in vegetation, Earth’s tilt or greenhouse gas concentrations—leaving tectonic action.


About 250 million years ago, a huge body of water called the Tethys Sea separated the supercontinents of Laurasia to the north and Gondwana to the south. As those supercontinents broke apart and shuffled around, the African plate collided with the Eurasian plate, birthing the Alps and the Himalayas but closing off the bulk of the Tethys Sea. As the plates kept moving, the sea continued to shrink, eventually diminishing into the Mediterranean.


What set off the aridification in Africa was the replacement of the western arm of the Tethys Sea with the Arabian Peninsula around 7 to 11 million years ago. Replacing water with land, which reflects less sunlight, altered the region’s precipitation patterns. This created the desert and heightened its sensitivity to changes in Earth’s tilt, the researchers conclude in a study published today in Nature.

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Ultrasensitive graphene sensor tracks down cancer biomarkers

Ultrasensitive graphene sensor tracks down cancer biomarkers | Amazing Science | Scoop.it
An ultrasensitive biosensor made from the wonder material graphene has been used to detect molecules that indicate an increased risk of developing cancer. The biosensor has been shown to be more than five times more sensitive than bioassay tests currently in use, and was able to provide results in a matter of minutes, opening up the possibility of a rapid, point-of-care diagnostic tool for patients.


The biosensor has been shown to be more than five times more sensitive than bioassay tests currently in use, and was able to provide results in a matter of minutes, opening up the possibility of a rapid, point-of-care diagnostic tool for patients. The biosensor has been presented today, 19 September, in IOP Publishing's journal 2D Materials.


To develop a viable bionsensor, the researchers, from the University of Swansea, had to create patterned graphene devices using a large substrate area, which was not possible using the traditional exfoliation technique where layers of graphene are stripped from graphite.


Instead, they grew graphene onto a silicon carbide substrate under extremely high temperatures and low pressure to form the basis of the biosensor. The researchers then patterned graphene devices, using semiconductor processing techniques, before attaching a number of bioreceptor molecules to the graphene devices. These receptors were able to bind to, or target, a specific molecule present in blood, saliva or urine.


The molecule, 8-hydroxydeoxyguanosine (8-OHdG), is produced when DNA is damaged and, in elevated levels, has been linked to an increased risk of developing several cancers. However, 8-OHdG is typically present at very low concentrations in urine, so is very difficult to detect using conventional detection assays, known as enzyme-linked immunobsorbant assays (ELISAs).


In their study, the researchers used x-ray photoelectron spectroscopy and Raman spectroscopy to confirm that the bioreceptor molecules had attached to the graphene biosensor once fabricated, and then exposed the biosensor to a range of concentrations of 8-OHdG.

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Stephen Wolfram: Introducing Tweet-a-Program

Stephen Wolfram: Introducing Tweet-a-Program | Amazing Science | Scoop.it

Wouldn't it be great if you could just call up a supercomputer and ask it to do your data-wrangling for you? Actually, scratch that, no-one uses the phone anymore. What'd be really cool is if machines could respond to your queries straight from Twitter. It's a belief that's shared by Wolfram Research, which has just launched the Tweet a Program system to its computational knowledge engine, Wolfram Alpha. In a blog post, founder Stephen Wolfram explains that even complex queries can be executed within the space of 140 characters, including data visualizations.


In the Wolfram Language a little code can go a long way. And to use that fact to let everyone have some fun with the introduction of Tweet-a-ProgramCompose a tweet-length Wolfram Language program, and tweet it to @WolframTaP. TheTwitter bot will run your program in the Wolfram Cloud and tweet the result back to you. One can do a lot with Wolfram Language programs that fit in a tweet. It’s easy to make interesting patterns or even complicated fractals. Putting in some math makes it easy to get all sorts of elaborate structures and patterns.


The Wolfram Language not only knows how to compute π, as well as a zillion other algorithms; it also has a huge amount of built-in knowledge about the real world. So right in the language, you can talk about movies or countries or chemicals or whatever. And here’s a 78-character program that makes a collage of the flags of Europe, sized according to country population. There are many, many kinds of real-world knowledge built into the Wolfram Language, including some pretty obscure ones. The Wolfram Language does really well with words and text and deals with images too.

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Fermi Paradox: Where is the Great Filter and Where Are We?

Fermi Paradox: Where is the Great Filter and Where Are We? | Amazing Science | Scoop.it

As many stars as there are in our galaxy (100 - 400 billion), there are roughly an equal number of galaxies in the observable universe -- so for every star in the colossal Milky Way, there's a whole galaxy out there. All together, that comes out to the typically quoted range of between 10**22 and 10**24 total stars, which means that for every grain of sand on Earth, there are 10,000 stars out there.


The science world isn't in total agreement about what percentage of those stars are "sun-like" (similar in size, temperature, and luminosity) -- opinions typically range from 5 percent to 20 percent. Going with the most conservative side of that (5 percent), and the lower end for the number of total stars (10**22), gives us 500 quintillion, or 500 billion billion sun-like stars.


There's also a debate over what percentage of those sun-like stars might be orbited by an Earth-like planet (one with similar temperature conditions that could have liquid water and potentially support life similar to that on Earth). Some say it's as high as 50 percent, but let's go with the more conservative 22 percent that came out of a recent PNAS study. That suggests that there's a potentially-habitable Earth-like planet orbiting at least 1 percent of the total stars in the universe -- a total of 100 billion billion Earth-like planets.


So there are 100 Earth-like planets for every grain of sand in the world. Think about that next time you're on the beach. Moving forward, we have no choice but to get completely speculative. Let's imagine that after billions of years in existence, 1 percent of Earth-like planets develop life (if that's true, every grain of sand would represent one planet with life on it). And imagine that on 1 percent of those planets, the life advances to an intelligent level like it did here on Earth. That would mean there were 10 quadrillion, or 10 million billion intelligent civilizations in the observable universe.


Moving back to just our galaxy, and doing the same math on the lowest estimate for stars in the Milky Way (100 billion), we'd estimate that there are 1 billion Earth-like planets and 100,000 intelligent civilizations in our galaxy.


So where is everybody?

Welcome to the Fermi Paradox. There is something called "The Great Filter". The Great Filter theory says that at some point from pre-life to Type III intelligence, there's a wall that all or nearly all attempts at life hit. There's some stage in that long evolutionary process that is extremely unlikely or impossible for life to get beyond. That stage is The Great Filter.  If this theory is true, the big question is, Where in the timeline does the Great Filter occur? This article gives different possibilities and scenarios.

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Time dilation directly measured at 40% of the speed of light — ions show that clocks do run slow at high speed

Time dilation directly measured at 40% of the speed of light — ions show that clocks do run slow at high speed | Amazing Science | Scoop.it

Einstein is most famous for general relativity, which is really a theory of gravity. But his theory of special relativity has been just as important. Special relativity is all about how to interpret measurements: if you measure the speed of an object from a moving vehicle, how do I reconcile that number with a measurement I make from the side of the road? At low speeds this is a fairly simple task, but at very high speeds things start to get strange. This strangeness arises as a consequence of the speed of light being constant.


Tests of the validity of special relativity abound, but they've been limited to a few classes of objects. The ones done in the lab are usually very sensitive experiments performed on relatively slow-moving objects, while natural tests use the motion of the Earth or other astronomical objects.


Now, a German facility has measured time dilation very accurately. But in a twist, these measurements were performed on things moving at just under 40 percent of the speed of light in the laboratoryThe researchers tested how clocks slow down when they are in motion. For example, if you are in motion relative to me, and I can see the watch on your hand, I should observe that it runs slightly slow compared to the one I'm wearing. Indeed, if you put an atomic clock in an airplane and fly it around the world, it will end up with a slightly different time than an identical clock that remained at the airport.


This time dilation is a consequence of a feature of physics called Lorentz invariance. Lorentz invariance is a way of saying that no matter where we are in the Universe, or how fast we are traveling, the Universe and its rules are basically the same.


The scientists verified in a very elegant experiment that special relativity and Lorentz invariance is true to one part in a billion. These results were also used to test some extensions to the Standard Model of physics, but these results were too inaccurate to provide much insight about the Standard Model. But there are competing models that may have much stronger deviations from Lorentz invariance. In these cases, the fact that these experiments didn't see any deviations will certainly be able to tell us something.


More importantly, though, the whole experiment is Earth-based, so we are not relying on any assumptions about astronomical objects. And even cooler, the experiment is in a regime where the objects actually have a speed that is quite high compared to normal lab experiments, which offers a whole new window on special relativity and Lorentz invariance.

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AAAS: Global Population Won't Stabilize This Century

AAAS: Global Population Won't Stabilize This Century | Amazing Science | Scoop.it
The population of Earth is unlikely to stabilize this century, according to a new analysis published in the 19 September issue of the journal Science. The findings are contrary to past studies, which have predicted that the world population will peak around 2050 and then level off or decline.

The results — based on a statistical analysis of the most recent population projections from the United Nations — suggest the global population will continue to grow through and beyond 2100. Based on their analysis, the researchers estimate an 80% probability that the world population, now 7.2 billion, will increase to between 9.6 and 12.3 billion by 2100.

"This finding is not completely in line with the conventional wisdom of the past 15 years," said co-author Adrian Raftery, professor of statistics and sociology at the University of Washington, "and this made us check all our results even more carefully."

"Our work," he said, "showed different results for two main reasons: new data and new methods."

The main driver of global population growth in their study is an increase in the projected population of Africa, the researchers found. Demographers had projected that the decline in fertility seen in Asia and Latin America since 1950 would continue in Africa, too, but Raftery and colleagues show that this decline has actually stalled in Africa.

What's more, many African women are still having larger families (the median size is 4.6 children), in part due to a lack of contraceptives. Mortality from HIV has been reduced in Africa as well, and the results of the study show the clear impact of this improvement.
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The first flexible graphene display paves the way for folding electronics

The first flexible graphene display paves the way for folding electronics | Amazing Science | Scoop.it
The first flexible display device based on graphene has been unveiled by scientists in the UK, who say it is the first step on the road towards next generation gadgets that can be folded, rolled or crumpled up without cracking the screen.
 
The device is the result of a collaboration between Plastic Logic, a company that specialises in flexible displays, and researchers led by Andrea Ferrari at the University of Cambridge. Although others have successfully used graphene to make screen components before, this is the first example of a flexible screen that uses graphene-based electronics.

‘What we have done here is to include graphene in the actual backplane pixel technology,’ says Ferrari. ‘This shows that in principle the properties of graphene – conductivity, flexibility and so on – can be exploited within a real-world display.’

Graphene researcher Jonathan Coleman from Trinity College Dublin in Ireland, who was not involved in the research, described the advance as a ‘major landmark’ that could help kick-start the commercialisation of graphene devices. ‘We need some sort of big win, and this could very well be it,’ he says.

The team’s prototype is an electrophoretic display containing the kind of ‘electronic ink’ found in e-readers that works by reflecting – rather than emitting – light. Plastic Logic have been working on making these displays flexible for some time by replacing the glass with bendy plastic, and using non-brittle components in the electronic layer. Graphene is an ideal material for this, as it is more flexible and more conductive than the metals currently used. The team managed to make the graphene electrode in a way that is compatible with electronics manufacturing, using solution processing rather than chemical vapour deposition, which often requires temperatures exceeding 1000°C.

‘All the major companies are trying to make bendable and flexible gadgets,’ says Ferrari. ‘We think that graphene will be a powerful addition to that, and if we manage to make the process easy, scalable and cheap enough, then it should be considered very strongly by industry.’

As current displays go, the team’s prototype is basic, capable of showing images in black and white at a resolution of 150 pixels per inch – akin to that of a basic e-reader. But Ferrari’s team are working on applying the same technology to make a graphene-based LCD and OLED displays like those used in smartphones and tablets, capable of showing full colour images and playing video. Their goal is to have these ready within the next 12 months.

Coleman thinks this target is achievable. ‘These solution processed graphene products tick a lot of the boxes that are required to develop these technologies,’ he says. ‘It’s hard to say whether they’ll get there, but I would be confident. The partners here are very well suited to achieve these goals.’
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World's manmade CO2 emissions must be cut by 7% per year to stop Earth's temperature rising by over 2˚C

World's manmade CO2 emissions must be cut by 7% per year to stop Earth's temperature rising by over 2˚C | Amazing Science | Scoop.it

Emissions of greenhouse gases are rising so fast that within one generation the world will have used up its margin of safety for limiting global warming to 2°C (3.6°F), an international team of scientists warned.


A report by the Global Carbon Project (GCP), published two days ahead of the UN climate summit on Tuesday, found that carbon dioxide (CO2) emissions from fossil-fuel combustion and cement production grew by 2.3 percent in 2013, reaching a record 36 billion tonnes of CO2. It predicted a further 2.5-percent increase in 2014.


It means that the world's "carbon quota" is fast being used up, according to the GCP research. Like an allowance, the quota is the maximum of heat-trapping gas that can be emitted before warming breaches 2°C as compared to the start of the Industrial Revolution in 1750.


"With current emission rates. the remaining 'quota' to surpass 2°C of global warming will be used up in around 30 years—or one generation," its authors said. "Total future CO2 emissions cannot exceed 1,200 billion tonnes for a likely—66 percent—chance of keeping average global warming under 2°C since pre-industrial times."


Member states have agreed to limit global warming to 2°C above pre-industrial levels, although they have not set a date by which this should be achieved.


The negotiations are supposed to climax in Paris at the end of 2015, providing a global pact that should come into force in 2020. But the talks are complex and bitterly-fought, with divisions over who should shoulder the burden of curbing the emissions.



Read more at: http://phys.org/news/2014-09-world-greenhouse-emissions-threaten-goal.html#jCp

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Engineered proteins from mussles and barnacles stick like glue—even in water

Engineered proteins from mussles and barnacles stick like glue—even in water | Amazing Science | Scoop.it
Shellfish such as mussels and barnacles secrete very sticky proteins that help them cling to rocks or ship hulls, even underwater. Inspired by these natural adhesives, a team of MIT engineers has designed new materials that could be used to repair ships or help heal wounds and surgical incisions.


To create their new waterproof adhesives, the MIT researchers engineered bacteria to produce a hybrid material that incorporates naturally sticky mussel proteins as well as a bacterial protein found in biofilms—slimy layers formed by bacteria growing on a surface. When combined, these proteins form even stronger underwater adhesives than those secreted by mussels.


This project, described in the Sept. 21, 2014 issue of the journal Nature Nanotechnology, represents a new type of approach that can be exploited to synthesize biological materials with multiple components, using bacteria as tiny factories.


"The ultimate goal for us is to set up a platform where we can start building materials that combine multiple different functional domains together and to see if that gives us better materials performance," says Timothy Lu, an associate professor of biological engineering and electrical engineering and computer science (EECS) and the senior author of the paper.


The researchers tested the adhesives using atomic force microscopy, a technique that probes the surface of a sample with a tiny tip. They found that the adhesives bound strongly to tips made of three different materials—silica, gold, and polystyrene. Adhesives assembled from equal amounts of mussel foot protein 3 and mussel foot protein 5 formed stronger adhesives than those with a different ratio, or only one of the two proteins on their own.


These adhesives were also stronger than naturally occurring mussel adhesives, and they are the strongest biologically inspired, protein-based underwater adhesives reported to date, the researchers say. The team also plans to try to create "living glues" consisting of films of bacteria that could sense damage to a surface and then repair it by secreting an adhesive.

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Physicists design zero-friction quantum engine

Physicists design zero-friction quantum engine | Amazing Science | Scoop.it

Scientists have devised a way to run a quantum cycle based on the use of quantum shortcuts to adiabaticity, where friction-like effects are quenched. In real physical processes, some energy is always lost any time work is produced. The lost energy almost always occurs due to friction, especially in processes that involve mechanical motion. But in a new study, physicists have designed an engine that operates with zero friction while still generating power by taking advantage of some quantum shortcuts.


The laws of thermodynamics successfully describe the concepts of work and heat in a wide variety of systems, ranging from refrigerators to black holes, as long as the systems are macroscopic. But for quantum technologies on the micro- and nano-scale, quantum fluctuationsthat are insignificant on large scales start to become prominent. As previous research as shown, the large quantum effects call for a complete reformulation of the thermodynamics laws.


What a quantum version of thermodynamics might look like is not yet known, and neither are the limitations or possible advantages of the quantum devices that would be described by such laws. However, one intriguing question is whether it may be possible to build a reversible quantum engine—one in which the engine's operation can be reversed without energy dissipation (an "adiabatic" process).


In the new paper, the physicists have shown one example of a quantum engine that is "super-adiabatic." That is, the engine uses quantum shortcuts to achieve a state that is usually achieved only by slow adiabatic processes. This engine can achieve a state that is fully frictionless; in other words, the engine reaches its maximum efficiency, while still generating some power.


"Shortcuts allow us to 'mimic' what would be achieved by running a cycle quasi-statically, i.e., very slowly, while performing transformations at finite time," coauthor Mauro Paternostro at Queen's University in Belfast, UK, told Phys.org. "Now, consider for instance a compression or expansion stage of a cycle run using a piston. When doing it at finite time, i.e., non-zero velocity, friction might affect the performance of the transformation. Yet, by using a shortcut to adiabaticity, friction-like effects would get quenched, the cycle performance being the same as that of a quasistatic motor."


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Global greenhouse gas emissions on course to reach record high of over 40bn tonnes in 2014

Global greenhouse gas emissions on course to reach record high of over 40bn tonnes in 2014 | Amazing Science | Scoop.it

Children born today will see the world committed to dangerous and irreversible levels of climate change by their young adulthood at current rates, as the world poured a record amount of greenhouse gases into the atmosphere this year.


Annual carbon dioxide emissions showed a strong rise of 2.5% on 2013 levels, putting the total emitted this year on track for 40bn tonnes. That means the global ‘carbon budget’, calculated as the total governments can afford to emit without pushing temperatures higher than 2C above pre-industrial levels, is likely to be used up within just one generation, or in thirty years from now.


Scientists think climate change is likely to have catastrophic and irreversible effects, including rising sea levels, polar melting, droughts, floods and increasingly extreme weather, if temperatures rise more than 2C. They have calculated that this threshold is likely to be breached if global emissions top 1,200 billion tonnes, giving a “carbon budget” to stick to in order to avoid dangerous warming.


Dave Reay, professor of carbon management at the University of Edinburgh, said: “If this were a bank statement it would say our credit is running out. We’ve already burned through two-thirds of our global carbon allowance and avoiding dangerous climate change now requires some very difficult choices. Not least of these is how a shrinking global carbon allowance can be shared equitably between more than 7bn people and where the differences between rich and poor are so immense.”


The study, by the Global Carbon Project, also found that China’s per capita emissions had surpassed those of Europe for the first time, between 2013 and 2014.


It comes ahead of a climate summit on Tuesday in New York, at which the UN secretary-general Ban Ki-moon will bring together heads of state and government from more than 120 countries to discuss climate change, and encourage them to make commitments on emissions reductions in the run-up to a crunch meeting in Paris late next year, at which a new global agreement on emissions is expected to be signed.


Emissions for 2014, according to the research, are set to rise to 40bn tonnes. That compares with emissions of 32bn tonnes in 2010, showing how fast the output is rising.


The rising trend has continued despite increasingly alarming warnings from scientists over the future of the climate, and commitments by developed countries to cut their carbon and from major developing economies to curb their emissions growth. There was a brief blip in global emissions growth at the time of the banking crisis, but this “breathing space” was quickly overtaken by an expansion in fossil fuel demand.

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Stanford researchers create a decoy version of Axl that may stop cancer from spreading

Stanford researchers create a decoy version of Axl that may stop cancer from spreading | Amazing Science | Scoop.it

A team of Stanford researchers has developed a protein therapy that disrupts the process that causes cancer cells to break away from original tumor sites, travel through the blood stream and start aggressive new growths elsewhere in the body. This process, known as metastasis, can cause cancer to spread with deadly effect.

"The majority of patients who succumb to cancer fall prey to metastatic forms of the disease," said Jennifer Cochran, an associate professor of bioengineering who describes a new therapeutic approach in Nature Chemical Biology. Today doctors try to slow or stop metastasis with chemotherapy, but these treatments are unfortunately not very effective and have severe side effects.


The Stanford team seeks to stop metastasis, without side effects, by preventing two proteins – Axl and Gas6 – from interacting to initiate the spread of cancer. Axl proteins are expressed on the surface of cancer cells, poised to receive biochemical signals from Gas6 proteins. When two Gas6 proteins link with two Axls, the signals that are generated enable cancer cells to leave the original tumor site, migrate to other parts of the body and form new cancer nodules.

To stop this process Cochran generated a harmless version of Axl that acts like a decoy ("dominant negative version of Axl). This decoy Axl latches on to Gas6 proteins in the blood stream and prevents them from linking with and activating the Axls present on cancer cells.

In collaboration with Professor Amato Giaccia, who heads the Radiation Biology Program in Stanford's Cancer Center, the researchers gave intravenous treatments of this bioengineered decoy protein to mice with aggressive breast and ovarian cancers.

Mice in the breast cancer treatment group had 78 percent fewer metastatic nodules than untreated mice. Mice with ovarian cancer had a 90 percent reduction in metastatic nodules when treated with the engineered decoy protein.

"This is a very promising therapy that appears to be effective and non-toxic in pre-clinical experiments," Giaccia said. "It could open up a new approach to cancer treatment."

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Physicists teleport the quantum state of a photon to a crystal over 25 kilometers of optical fiber

Physicists teleport the quantum state of a photon to a crystal over 25 kilometers of optical fiber | Amazing Science | Scoop.it

Physicists at the University of Geneva have succeeded in teleporting the quantum state of a photon to a crystal over 25 kilometers of optical fiber. The experiment, carried out in the laboratory of Professor Nicolas Gisin, constitutes a first, and simply pulverises the previous record of 6 kilometres achieved ten years ago by the same UNIGE team. Passing from light into matter, using teleportation of a photon to a crystal, shows that, in quantum physics, it is not the composition of a particle which is important, but rather its state, since this can exist and persist outside such extreme differences as those which distinguish light from matter. The results obtained by Félix Bussières and his colleagues are reported in the latest edition of Nature Photonics.


Quantum physics, and with it the UNIGE, is again being talked about around the world with the Marcel Benoist Prize for 2014 being awarded to Professor Nicolas Gisin, and the publication of experiments in Nature Photonics. The latest experiments have enabled verifying that the quantum state of a photon can be maintained whilst transporting it into a crystal without the two coming directly into contact. One needs to imagine the crystal as a memory bank for storing the photon's information; the latter is transferred over these distances using the teleportation effect.


The experiment not only represents a significant technological achievement but also a spectacular advance in the continually surprising possibilities afforded by the quantum dimension. By taking the distance to 25 kilometres of optical fibre, the UNIGE physicists have significantly surpassed their own record of 6 kilometres, the distance achieved during the first long-distance teleportation achieved by Professor Gisin and his team in 2003.

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New insights on an ancient plague could improve modern treatments for infections

New insights on an ancient plague could improve modern treatments for infections | Amazing Science | Scoop.it
While bubonic plague would seem a blight of the past, there have been recent outbreaks in India, Madagascar and the Congo. And it's mode of infection now appears similar to that used by other well-adapted human pathogens, such as the HIV virus.


In their study, the Duke and Duke-NUS researchers set out to determine whether the large swellings that are the signature feature of bubonic plague -- the swollen lymph nodes, or buboes at the neck, underarms and groins of infected patients -- result from the pathogen or as an immune response.


It turns out to be both. "The bacteria actually turn the immune cells against the body," said senior author Soman Abraham, Ph.D. a professor of pathology at Duke and professor of emerging infectious diseases at Duke-NUS. "The bacteria enter the draining lymph node and actually hide undetected in immune cells, notably the dendritic cells and monocytes, where they multiply. Meanwhile, the immune cells send signals to bring in even more recruits, causing the lymph nodes to grow massively and providing a safe haven for microbial multiplication."


The bacteria are then able to travel from lymph node to lymph node within the dendritic cells and monocytes, eventually infiltrating the blood and lungs. From there, the infection can spread through body fluids directly to other people, or via biting insects such as fleas.
Abraham, St. John and colleagues note that there are several potential drug candidates that target the trafficking pathways that the bubonic plague bacteria use. In animal models, the researchers successfully used some of these therapies to prevent the bacteria from reaching systemic infection, markedly improving survival and recovery.


"This work demonstrates that it may be possible to target the trafficking of host immune cells and not the pathogens themselves to effectively treat infection and reduce mortality," St. John said. "In view of the growing emergency of multi-resistant bacteria, this strategy could become very attractive."

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Lilia Hernández's curator insight, Today, 7:06 AM

No lo puedo evitar, la microbiología siempre será mi más grande pasión. Noticias de cazadores de microbios :)

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A 15 Centimeter Hagfish Nano-thread With Near Gigapascal Tensile Strength Is Wound Up In A Single Cell

A 15 Centimeter Hagfish Nano-thread With Near Gigapascal Tensile Strength Is Wound Up In A Single Cell | Amazing Science | Scoop.it

In self-defense the hagfish produces from its glands a slime that is composed of nanometer width threads and what is likely sugar or glyco-modifications.  The slime is thought to impede capture by making the hagfish slippery, and possibly by clogging the gills of a predator.  The nanothreads are remarkable: comparable to spider silk in tensile strength (800 megapascals or near 1 gigapascal) and lightness, and 5 times stronger than steel on a weight basis. Moreover, each thread is only 12 nanometers wide but 15 centimeters long.  Amazingly, a full thread is wrapped up in so that it fits within a single cell, highly specialized and called a gland thread cell (GTC).


Scientists have uncovered, using electron microscopy, the organization of a single hagfish nano-sized thread, helping resolve the mystery of why extrusion of such a long (compared to its width) thread from the cell does not cause tangling.  The thread is coiled up in a conical “skein” in 15-20 layers.  As a GTC matures, its nucleus migrates to an extreme pole, leaving most of the cell volume packed with a single coil of thread.


The conical shape of the coiling seems to be controlled by the shape of the nucleus of the GTC which deforms over time from being round to being elongated.  The first layer of coils observed by the researchers is round with subsequent layers becoming more elongated.  Therefore the nucleus provides an evolving “obstruction” which restricts the freedom of the thread and organizes it over the maturation time.


The authors used a method known as Focused Ion Beam Scanning Electron Microscopy or (FIB-SEM) to scan a matured GTC.  The great advantage of FIB-SEM is the ability to acquire image slices through a succession of scanned planes.   Software then takes image slices to reconstruct a 3D representation.


Attempts to industrialize strong, natural nanofibers with extraordinary properties have met with limited success.  Harvesting silk from the silk worm in bulk is routine and has a history of thousands of years.  But silk does not have the tensile properties of spider or hagfish thread.  Harvesting spider silk is not doable on an industrial scale partly due to our inability to amass sufficient production volume, although there are some ongoing efforts to engineer the proteins into another organism such as a silkworm or bacteria that affords better control over production capacity.

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Intel putting 3D scanners in consumer tablets next year, phones to follow

Intel putting 3D scanners in consumer tablets next year, phones to follow | Amazing Science | Scoop.it

Intel has been working on a 3D scanner small enough to fit in the bezel of even the thinnest tablets. The company aims to have the technology in tablets from 2015, with CEO Brian Krzanich telling the crowd at MakerCon in New York on Thursday that he hopes to put the technology in phones as well.


"Our goal is to just have a tablet that you can go out and buy that has this capability," Krzanich said. "Eventually within two or three years I want to be able to put it on a phone."


Krzanich and a few of his colleagues demonstrated the technology, which goes by the name "RealSense," on stage using a human model and an assistant who simply circled the model a few times while pointing a tablet at the subject. A full 3D rendering of the model slowly appeared on the screen behind the stage in just a few minutes. The resulting 3D models can be manipulated with software or sent to a 3D printer.


"The idea is you go out, you see something you like and you just capture it," Krzanich explained. He said consumer tablets with built in 3D scanners will hit the market in the third or fourth quarter of 2015, with Intel also working on putting the 3D scanning cameras on drones.


The predecessor to the 3D scanning tablets demonstrated on stage were announced earlier this month in the form of the Dell Venue 8 7000 series Android tablet sports Intel's RealSense snapshot depth camera, which brings light-field camera-like capabilities to a tablet. It will be available later this year.

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Study shows how epigenetic memory is passed across generations

Study shows how epigenetic memory is passed across generations | Amazing Science | Scoop.it

A growing body of evidence suggests that environmental stresses can cause changes in gene expression that are transmitted from parents to their offspring, making "epigenetics" a hot topic. Epigenetic modifications do not affect the DNA sequence of genes, but change how the DNA is packaged and how genes are expressed. Now, a study by scientists at UC Santa Cruz shows how epigenetic memory can be passed across generations and from cell to cell during development.

The study, published September 19, 2014 in Science, focused on one well studied epigenetic modification--the methylation of a DNA packaging protein called histone H3. Methylation of a particular amino acid (lysine 27) in histone H3 is known to turn off or "repress" genes, and this epigenetic mark is found in all multicellular animals, from humans to the tiny roundworm C. elegans that was used in this study.


"There has been ongoing debate about whether the methylation mark can be passed on through cell divisions and across generations, and we've now shown that it is," said corresponding author Susan Strome, a professor of molecular, cell and developmental biology at UC Santa Cruz.


Strome's lab created worms with a mutation that knocks out the enzyme responsible for making the methylation mark, then bred them with normal worms. Using fluorescent labels, they were able to track the fates of marked and unmarked chromosomes under the microscope, from egg cells and sperm to the dividing cells of embryos after fertilization. Embryos from mutant egg cells fertilized by normal sperm had six methylated chromosomes (from the sperm) and six unmarked or "naked" chromosomes (from the egg).


As embryos develop, the cells replicate their chromosomes and divide. The researchers found that when a marked chromosome replicates, the two daughter chromosomes are both marked. But without the enzyme needed for histone methylation, the marks become progressively diluted with each cell division.


"The mark stays on the chromosomes derived from the initial chromosome that had the mark, but there's not enough mark for both daughter chromosomes to be fully loaded," Strome said. "So the mark is bright in a one-cell embryo, less bright after the cell divides, dimmer still in a four-cell embryo, and by about 24 to 48 cells we can't see it anymore."


The researchers then did the converse experiment, fertilizing normal egg cells with mutant sperm. The methylation enzyme (called PRC2) is normally present in egg cells but not in sperm, which don't contribute much more than their chromosomes to the embryo. So the embryos in the new experiment still had six naked chromosomes (this time from the sperm) and six marked chromosomes, but now they also had the enzyme.


"Remarkably, when we watch the chromosomes through cell divisions, the marked chromosomes remain marked and stay bright, because the enzyme keeps restoring the mark, but the naked chromosomes stay naked, division after division," Strome said. "That shows that the pattern of marks that was inherited is being transmitted through multiple cell divisions."

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Helen Teague's curator insight, September 19, 9:54 PM

A growing body of evidence suggests that environmental stresses can cause changes in gene expression that are transmitted from parents to their offspring, making "epigenetics" a hot topic. Epigenetic modifications do not affect the DNA sequence of genes, but change how the DNA is packaged and how genes are expressed. Now, a study by scientists at UC Santa Cruz shows how epigenetic memory can be passed across generations and from cell to cell during development.

The study, published September 19, 2014 in Science, focused on one well studied epigenetic modification--the methylation of a DNA packaging protein called histone H3. Methylation of a particular amino acid (lysine 27) in histone H3 is known to turn off or "repress" genes, and this epigenetic mark is found in all multicellular animals, from humans to the tiny roundworm C. elegans that was used in this study.

 

"There has been ongoing debate about whether the methylation mark can be passed on through cell divisions and across generations, and we've now shown that it is," said corresponding author Susan Strome, a professor of molecular, cell and developmental biology at UC Santa Cruz.

 

Strome's lab created worms with a mutation that knocks out the enzyme responsible for making the methylation mark, then bred them with normal worms. Using fluorescent labels, they were able to track the fates of marked and unmarked chromosomes under the microscope, from egg cells and sperm to the dividing cells of embryos after fertilization. Embryos from mutant egg cells fertilized by normal sperm had six methylated chromosomes (from the sperm) and six unmarked or "naked" chromosomes (from the egg).

 

As embryos develop, the cells replicate their chromosomes and divide. The researchers found that when a marked chromosome replicates, the two daughter chromosomes are both marked. But without the enzyme needed for histone methylation, the marks become progressively diluted with each cell division.

 

"The mark stays on the chromosomes derived from the initial chromosome that had the mark, but there's not enough mark for both daughter chromosomes to be fully loaded," Strome said. "So the mark is bright in a one-cell embryo, less bright after the cell divides, dimmer still in a four-cell embryo, and by about 24 to 48 cells we can't see it anymore."

 

The researchers then did the converse experiment, fertilizing normal egg cells with mutant sperm. The methylation enzyme (called PRC2) is normally present in egg cells but not in sperm, which don't contribute much more than their chromosomes to the embryo. So the embryos in the new experiment still had six naked chromosomes (this time from the sperm) and six marked chromosomes, but now they also had the enzyme.

 

"Remarkably, when we watch the chromosomes through cell divisions, the marked chromosomes remain marked and stay bright, because the enzyme keeps restoring the mark, but the naked chromosomes stay naked, division after division," Strome said. "That shows that the pattern of marks that was inherited is being transmitted through multiple cell divisions."

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Making drones more customizable: First-ever standard “operating system” for drones

Making drones more customizable: First-ever standard “operating system” for drones | Amazing Science | Scoop.it

A first-ever standard “operating system” for drones, developed by a startup with MIT roots, could soon help manufacturers easily design and customize unmanned aerial vehicles (UAVs) for multiple applications.


Today, hundreds of companies worldwide are making drones for infrastructure inspection, crop- and livestock-monitoring, and search-and-rescue missions, among other things. But these are built for a single mission, so modifying them for other uses means going back to the drawing board, which can be very expensive.


Now Airware, founded by MIT alumnus Jonathan Downey ’06, has developed a platform — hardware, software, and cloud services — that lets manufacturers pick and choose various components and application-specific software to add to commercial drones for multiple purposes.


The key component is the startup’s Linux-based autopilot device, a small red box that is installed into all of a client’s drones. “This is responsible for flying the vehicle in a safe, reliable manner, and acts as hub for the components, so it can collect all that data and display that info to a user,” says Downey, Airware’s CEO, who researched and built drones throughout his time at MIT.


To customize the drones, customers use software to select third-party drone vehicles and components — such as sensors, cameras, actuators, and communication devices — configure settings, and apply their configuration to a fleet. Other software helps them plan and monitor missions in real time (and make midflight adjustments), and collects and displays data. Airware then pushes all data to the cloud, where it’s aggregated and analyzed, and available to designated users.


If a company decides to use a surveillance drone for crop management, for instance, it can easily add software that stitches together different images to determine which areas of a field are overwatered or underwatered. “They don’t have to know the flight algorithms, or underlying hardware, they just need to connect their software or piece of hardware to the platform,” Downey says. “The entire industry can leverage that.”


Clients have trialed Airware’s platform over the past year — including researchers at MIT, who are demonstrating delivery of vaccines in Africa. Delta Drone in France is using the platform for open-air mining operations, search-and-rescue missions, and agricultural applications. Another UAV maker, Cyber Technology in Australia, is using the platform for drones responding to car crashes and other disasters, and inspecting offshore oilrigs.


Now, with its most recent $25 million funding round, Airware plans to launch the platform for general adoption later this year, viewing companies that monitor crops and infrastructure — with drones that require specific cameras and sensors — as potential early customers.

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Primal pull of a baby crying reaches across species

Primal pull of a baby crying reaches across species | Amazing Science | Scoop.it

There is something primal in a mother's response to a crying infant. So primal, in fact, that mother deer will rush protectively to the distress calls of other infant mammals, such as fur seals, marmots and even humans. This suggests such calls might share common elements – and perhaps that these animals experience similar emotions.


Researchers – and, indeed, all pet owners – know that humans respond emotionally to the distress cries of their domestic animals, and there is some evidence that dogs also respond to human cries. However, most people have assumed this is a by-product of domestication.


However, Susan Lingle, a biologist at the University of Winnipeg, Canada, noticed that the infants of many mammal species have similar distress calls: simple sounds with few changes in pitch. She decided to test whether cross-species responses occur more widely across the evolutionary tree.


So, Lingle and her colleague Tobias Riede, now at Midwestern University in Glendale, Arizona, recorded the calls made by infants from a variety of mammal species when separated from their mother or otherwise threatened. They then played the recordings through hidden speakers to wild mule deer (Odocoileus hemionus) out on the Canadian prairies. They found that deer mothers quickly moved towards the recordings of infant deer, but also towards those of infant fur seals, dogs, cats and humans, all of which call at roughly the same pitch. Even the ultrasonic calls of infant bats attracted the deer mothers if Lingle used software to lower their pitch to match that of deer calls. In contrast, they found the deer did not respond to non-infant calls such as birdsong or the bark of a coyote (American NaturalistDOI: 10.1086/677677).

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Are cosmic high-energy electrons to blame for the right-handedness of DNA on Earth?

Are cosmic high-energy electrons to blame for the right-handedness of DNA on Earth? | Amazing Science | Scoop.it

The DNA of every organism on Earth is a right-handed double helix, but why that would be has puzzled scientists since not long after Francis Crick and James Watson announced the discovery of DNA's double-helical structure in 1953. It's a puzzle because no one has been able to think of a fundamental reason why DNA couldn't also be left-handed.


New research by University of Nebraska-Lincoln physicists and published in the Sept. 12 online edition of Physical Review Letters now gives support to a long-posited but never-proven hypothesis that electrons in cosmic rays -- which are mostly left-handed -- preferentially destroyed left-handed precursors of DNA on the primordial Earth.

The hypothesis, called the Vester-Ulbricht model, was proposed by Frederic Vester of the University of Saarbrucken in Germany and Tilo L.V. Ulbricht of the University of Cambridge in England in 1961 in response to the 1957 discovery that most of the electrons spewing from radioactive beta decay were left-handed.


Joan M. Dreiling and Timothy J. Gay of UNL focused circularly polarized laser light on a specially prepared crystal of gallium-arsenide to produce electrons whose spins were either parallel or anti-parallel to their direction of motion upon emission from the crystal -- essentially artificial beta rays. They then directed these electrons to strike target molecules of a substance called bromocamphor, which comes in both right- and left-handed varieties.


They found that at the lowest electron energies they studied, left-handed electrons preferentially destroyed left-handed molecules and vice versa. This sensitivity to molecular handedness has a mechanical analog: the inability of a left-handed bolt to screw into a right-handed nut. The molecular experiment proves the principle underlying the Vester-Ulbricht hypothesis.


"The circular polarization of the laser light effectively transferred to the spin (handedness) of the electrons emitted by the gallium-arsenide crystal," said Dreiling, a postdoctoral research assistant who received her doctorate from UNL in May. "We are able to reverse the spin-polarization of the electrons just by reversing the circular polarization of the light."


The effect they saw was quite small, they said -- like "looking for an electronic needle in a haystack," Gay said -- but they said they're highly confident in their result. "We have done several different checks with our experiment and I am totally confident that the asymmetry exists," Dreiling said. "The checks all came out showing that this asymmetry is real."

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