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During harvest last year, banana farmers in Jordan and Mozambique made a chilling discovery. Their plants were no longer bearing the soft, creamy fruits they'd been growing for decades. When they cut open the roots of their banana plants, they saw something that was turning banana plants into a rotting mass.
Scientists first discovered the fungus that is turning banana plants into this rotting mass in Southeast Asia in the 1990s. Since then the pathogen, known as the Tropical Race 4 strain of Panama disease, has slowly but steadily ravaged export crops throughout Asia. The fact that this vicious soil-borne fungus has now made the leap to Mozambique and Jordan is frightening. One reason is that it’s getting closer to Latin America, where at least 70% of the world’s $8.9-billion-a-year worth of exported bananas is grown.
Chiquita, the $548-million fruit giant with the world’s largest banana market share, is downplaying the risk. ”It’s certainly not an immediate threat to banana production in Latin America [where Chiquita's crops are],” Ed Lloyd, spokesman for Chiquita, told the Charlotte Business Journal in late December, explaining that the company is using a “risk-mitigation program” to approach the potential spread.
Even if it takes longer to arrive, the broader ravaging of the commercial banana appears inevitable. And we don’t need to imagine what that would mean for banana exports—the exact scenario has already happened. Starting in 1903, Race 1, an earlier variant of today’s pathogen, ravaged the export plantations of Latin America and the Caribbean. Within 50 years, Race 1 drove the world’s only export banana species, the Gros Michel, to virtual extinction. That’s why 99% of the bananas eaten in the developed world today are a cultivar called the Cavendish, the only export-suitable banana that could take on Race 1 and live to tell.
Over the half-century it took to wipe out the Gros Michel, Race 1 caused at least $2.3 billion in damage (around $18.2 billion in today’s terms.) And that was in the commercial heart of global banana production. Tropical Race 4, by comparison, has damaged $400 million in banana crops in the Philippines alone.
But the bigger difference now is that, compared its 20th-century cousin, Tropical Race 4 is a pure killing machine—and not just for Cavendishes. Scores of other species that are immune to Race 1 have no defenses against the new pathogen. In fact, Tropical Race 4 is capable of killing at least 80%—though possibly as much as 85%—of the 145 million tonnes (160 million tons) of bananas and plantains produced each year, says Ploetz.
In humans, a tiny area in the center of the retina called the fovea is critically important to viewing fine details. Densely packed with cone photoreceptor cells, it is used while reading, driving and gazing at objects of interest. Some animals have a similar feature in their eyes, but researchers believed that among mammals the fovea was unique to primates — until now.
University of Pennsylvania vision scientists report that dogs, too, have an area of their retina that strongly resembles the human fovea. What’s more, this retinal region is susceptible to genetic blinding diseases in dogs just as it is in humans.
“It’s incredible that in 2014 we can still make an anatomical discovery in a species that we’ve been looking at for the past 20,000 years and that, in addition, this has high clinical relevance to humans,” said William Beltran, an assistant professor of ophthalmology in Penn’s School of Veterinary Medicine.
The word “fovea” comes from the Latin meaning “pit,” owing to the fact that in humans and many other primates, the inner layers of the retina are thin in this area, while the outer layers are packed with cone photoreceptor cells. It is believed that this inner layer thinning allows the foveal cone cells privileged access to light.
It is known that dogs have what is called an area centralis, a region around the center of the retina with a relative increase in cone photoreceptor cell density. But dogs lack the pit formation that humans have, and, before this study, it was believed that the increase in cone photoreceptor cell density didn’t come close to matching what is seen in primates. Prior to this study, the highest reported density in dogs was 29,000 cones per square millimeter compared to more than 100,000 cones per square millimeter seen in the human and macaque foveas.
It turns out that previous studies in dogs had missed a miniscule region of increased cell density. In this study, while examining the retina of a dog with a mutation that causes a disease akin to a form of X-linked retinal degeneration in humans, the Penn researchers noticed a thinning of the retinal layer that contains photoreceptor cells.
Zeroing in on this region, they examined retinas of normal dogs using advanced imaging techniques, including confocal scanning laser ophthalmoscopy, optical coherence tomography and two-photon microscopy. By enabling the scientists to visualize different layers of the retina, these techniques allowed them to identify a small area of peak cone density and then estimate cone numbers by counting the cells in this unique area.
Based on their observations, the researchers found that cone densities reached more than 120,000 cells per square millimeter in a never-before-described fovea-like region within the area centralis — a density on par with that of primate foveas.
Human patients with macular degeneration experience a loss of photoreceptor cells — the rods and cones that process light — at or near the fovea, resulting in a devastating loss of central vision. To see whether the fovea-like region was similarly affected in dogs, the Penn researchers used the same techniques they had employed to study normal dogs to examine animals that had mutations in two genes (BEST1 and RPGR) that can lead to macular degeneration in humans.
In both cases, the onset of disease affected the fovea-like region in dogs in a very similar way to how the diseases present in humans -- with central retinal lesions appearing earlier than lesions in the peripheral retina.
This is the clearest evidence that our ancestors speared and killed the extinct giant.
These unique photographs seen by the world for the first time show the wounded vertebrae of the woolly mammoth found in Siberia. Forensic evidence proves the hole was made by a spear or javelin, meaning the huge creature was slain by ancient man some 13,470 years ago. It does not answer the conundrum that still puzzles scientists: why did the mammoths vanish from the face of the planet? Man's butchery may have been a factor, but can it really be the only one? Our exclusive pictures from Khanty-Mansiysk show the remains of a mammoth located a dozen years ago close to the confluence of the rivers Ob and Irtysh in the west of Siberia.
The images show the thoracic vertebrae of a mammoth, which in all probability was marooned in a clay swamp when the hunters went in for the kill. It is believed the weapon was thrown with great force at the creature. The vertebrae is pierced by a cone-shaped hole resulting from the penetration of a notched point, and there are fragments of quartzite flakes lodged inside, according to Russian scientists.
The discovery was made at the Lugovskoe 'mammoth graveyard' by scientists Alexander Pavlov and Eugeny Mashchenko in a swampy area where thousands of bones of mammals - mainly mammoths - have been unearthed by scientists since the 1990s. It remains unclear to what extent our ancestors ate the woolly mammoth when other, perhaps more succulent, food sources were available. Yet a related discovery last year in Lugovskoe was the remains of a 13,270 year old fireplace belonging to early men in this region.
The current theory is that mammoth bone was burned with charcoal, the fat from the bone giving a superior heat. Anton Rezvy, 39, head of the palaeontological department of the Khanty-Mansiysk Museum of Nature and Man, explained: 'The vertebra was found in Lugovskoe mammoth cemetery.'
There’s a scene in the 1988 movie Rain Man in which Raymond Babbitt (played by Dustin Hoffman) recites a waitress’s phone number. Naturally the waitress is shocked. Instead of mental telepathy, Raymond had memorized the entire telephone book and instantly recognized the name on her nametag. Hoffman’s character was heavily influenced by the life of Kim Peek, a real memory savant who recently passed away. Peek was born without a corpus callosum, the fibers that connect the right and left hemispheres of the brain. He was also born missing parts of the cerebellum, which is important for motor control and the learning of complex, well-rehearsed routines. But what Peek lacked in brain connections and conceptual cognitive functioning, he more than made up for in memory. He had the extraordinary ability to memorize any text in just one sitting. With two pages in front of him, he had the uncanny ability for each eye to focus on a different page. His repertoire included the Bible, the complete works of Shakespeare, U.S. area codes and zip codes, and roughly 12,000 other books. He was known to stop performances to correct actors and musicians who had made a mistake! He could also tell you what day of the week your birthday fell on in any year.
Savantism disproportionately affects males, with about five male savants for every one female, and the syndrome generally occurs in people with IQs between 40 and 70. Like others with ASD, when savants take IQ tests they tend to score higher on nonverbal problems than verbal problems. As Darold Treffert, a world-renowned expert on savant syndrome, observes, “IQ scores, in my experience with savants, fail to adequately capture and reflect the many separate elements and abilities that contribute to ‘intelligence’ overall in everyone.”
Even so, savants vary markedly in their abilities. Savant skills fall along a continuum, ranging from “splinter skills” (such as memorization of license plates), to “talented” savants who have musical or artistic skills that exceed what is expected based on their handicap, to “prodigious” savants where the skill is so remarkable it would be impressive with or without the disability. To date, fewer than 100 prodigious savants have been documented. Interestingly, there is almost always no “dreaded trade-off ” between the incredible skills of savants and their development of language, social skills, and daily living functioning.
How can we explain the extraordinary feats of savants? No one knows the whole story, but there are some clues. Bernard Rimland, who passed away in 2006, maintained the largest database in the world of people with autism (more than 34,000 cases). He observed that the savant skills that were most frequently present were right-hemisphere skills, and their deficits were most strongly associated with left-hemisphere functions.
It is estimated that as much as 99% of medicinal molecules administered during a therapy don't reach their targets and subsequently stay in the body of the patient. Some of these molecules can be very toxic, especially cancer drugs, and the potential side effects of many therapeutic drugs can be downright frightening – just read the instruction leaflet that comes with your pills.These effects often occur when a drug is active throughout the body, not just where and when it is needed. As opposed to having patients simply swallow a pill, health care professionals have long envisioned delivering specific quantities of medicines to targeted areas of the body, thereby increasing the treatment’s effectiveness while reducing side effects. In order to achieve this, a 'vehicle' of sorts is needed to safely and accurately deliver the medicine to the desired location within the body.
The ultimate goal of nanotechnology-enabled drug delivery, especially with regard to cancer therapy, is to ferry most of the administered drug to the target, while eliminating the accumulation of the drug at any non-target tissues.
Nanomedicine applications with targeted nanoparticles are expected to revolutionize cancer therapy. The use of such nanoparticles to deliver therapeutic agents is currently being studied as a promising method by which drugs can be effectively targeted to specific cells in the body, such as tumor cells.Biological barriers – the skin, mucosal membranes, the blood-brain barrier and cell/nuclear membranes – seriously limit the delivery of drugs into the desired sites within the body, resulting in a low delivery efficacy, poor therapeutic efficacy, and high cost.Nanomedicine researchers have developed numerous biological, chemical, and physical strategies to overcome these barriers.
Bottlenose dolphins use auditory (or echoic) information to recognize their environments, and many studies have described their echolocation perception abilities. However, relatively few systematic studies have examined their visual perception. A team of scientists now tested dolphins on a visual-matching task using two-dimensional geometric forms including various features. Based on error patterns, they used multidimensional scaling to analyze perceptual similarities among stimuli. In addition to dolphins, they conducted comparable tests with terrestrial species: chimpanzees were tested on a computer-controlled matching task and humans were tested on a rating task. The overall perceptual similarities among stimuli in dolphins were similar to those in the two species of primates. These results clearly indicate that the visual world is perceived similarly by the three species of mammals, even though each has adapted to a different environment and has differing degrees of dependence on vision.
Because dolphins have adapted to an underwater environment, they have developed a perceptual system that differs considerably from that of terrestrial mammals such as primates. One strikingly different aspect of the perceptual system of dolphins is echolocation1,. They can recognize shapes, materials, and the texture of objects using this form of biological sonar. Many echolocation studies on cetaceans have been conducted both in the laboratory and in the wild4. A few studies have investigated dolphins' ability to use cross-modal integration through vision–echolocation matching5, 6,. In these studies, dolphins were very accurate in matching three-dimensional complex objects using information gathered via echolocation. On the other hand, these results indirectly suggest that dolphins may also visually discriminate complex objects. Dolphins (e.g., bottlenose dolphins) have poorer in-air and underwater visual acuity (12.6 min of visual angle from a distance of 2.5 m) than that of primates10. Nevertheless, they still visually recognize and discriminate human gestural signs11, 12, 13, mirror images of themselves14, 15, numbers of objects16, three-dimensional objects4, 17, and two-dimensional forms17, 18. Moreover, researchers have used visual stimuli to study the basic features of the vision and various cognitive abilities of dolphins17, 18.
How can a super-thin 3-inch disk levitate something 70,000 times its own weight? In a riveting demonstration, Boaz Almog shows how a phenomenon known as quantum locking allows a superconductor disk to float over a magnetic rail -- completely frictionlessly and with zero energy loss. Experiment: Prof. Guy Deutscher, Mishael Azoulay, Boaz Almog, of the High Tc Superconductivity Group, School of Physics and Astronomy, Tel Aviv University.
It is three years since India last reported a case of polio. Patralekha Chatterjee reports on how the country appears to have finally managed to beat the disease. Despite a healthcare system beset by severe problems, India has ushered in the new year with an achievement to be proud of.
In 2009, India reported 741 polio cases, more than any other country in the world, according to the Global Polio Eradication Initiative. The last case was reported from the eastern state of West Bengal in 2011, when an 18-month-old girl was found to have contracted the disease.
The country faced unique challenges in eradicating polio.
Among them was the high population density and birth rate, poor sanitation, widespread diarrhea, inaccessible terrain and reluctance of a section of the population, notably members of the Muslim community in certain pockets, to accept the polio vaccine.
Nicole Deutsch, head of polio operations in India for UN children's charity Unicef, said: "Despite these obstacles, India proved to the world how to conquer this disease: through the strong commitment of the government, seamless partnership comprising the government, Rotary clubs, WHO and Unicef, and above all the tireless hard work of millions of front-line workers - vaccinators, social mobilisers and community and health workers - who continue to implement innovative strategies to rid India of polio,"
The introduction of bivalent oral polio vaccine in 2010 also helped India to battle the disease. Previously, India had been using a monovalent vaccine that protected only against type 1 poliovirus transmission, not type 3. which was causing repeated disease outbreaks.
But it was organisation that was key in enabling India to cover the last mile in its battle against polio.
Apple is accelerating the race to make smartphone applications easier and safer to use in cars.
Ferrari, Mercedes-Benz and Volvo are previewing Apple's iPhone technology for cars this week at an auto show in Geneva. The partnerships give Apple an early lead over Google's loosely knit family of Android phones in a duel to make mobile applications more accessible while drivers are behind the wheel. Apple's iOS mobile software and Google's Android operating system power most of the smartphones in the world.
Just two months ago, Google Inc. announced it is working with several major automakers to turn Android phones into an essential part of cars. Google hopes to finish work on its system for tethering Android phones to cars by the end of this year.
Apple Inc. announced its automobile ambitions nine months ago when it unveiled its "iOS in the Car" initiative—a reference to the operating system that powers the iPhone and iPad. Now that the idea is moving closer to reality, Apple is renaming the technology "CarPlay."
The system announced Monday enables iPhones to plug into cars so drivers can call up maps, make calls and request music with voice commands or a touch on a vehicle's dashboard screen.
By making smartphones work more seamlessly with automobiles, both Apple and Google are hoping to immerse their services even deeper into peoples' lives. In doing so, the companies expect to make money by selling advertising, applications and upgrades on smartphones that will become even more indispensable.
"IPhone users always want their content at their fingertips and CarPlay lets drivers use their iPhone in the car with minimized distraction," said Greg Joswiak, Apple's vice president of iPhone and iOS product marketing.
Automakers are hoping vehicles that are compatible with the top-selling smartphones will be easier to sell to consumers who can't fathom living without the devices.
Cars of recent vintage increasingly feature electronics designed to cater to drivers' high-tech desires, but those systems still haven't attracted a widespread following. That has led more automakers to conclude that it makes sense to work directly with technology companies such as Apple and Google to turn their cars into smartphone extensions.
CarPlay requires Apple's latest mobile software, iOS 7, and an iPhone 5, 5C or 5S.
Researchers in the US have taken an important step towards understanding exactly how single-walled carbon nanotubes (SWCNTs) boost the performance of lithium-ion batteries. The team found that metallic SWCNTs are able to accommodate more lithium atoms than semiconducting SWCNTs, which could lead to better performance. The research also reveals how semiconducting SWCNTs could be made to take up more lithium. The work could have a broad practical impact because lithium-ion batteries are used in a range of portable electronic devices.
SWCNTs are frequently employed as additives in lithium-ion batteries to improve the lifetime of the battery and its charge and discharge rates. However, SWCNTs come in two electronic flavours – metallic and semiconducting – and it was not clear whether both types were boosting performance or if one flavour was responsible for the bulk of the improvement.
Now, researchers at Northwestern University and the Argonne National Laboratory in the US have found that a nanotube's electronic type affects how easily it can accommodate lithium. Their research also reveals that the spacing between nanotubes in a battery also appears to influence the uptake of lithium.
The team, led by Mark Hersam of Northwestern, used a technique called density gradient ultracentrifugation (DGU) to separate metallic and semiconducting SWCNTs. SWCNTs are always produced in a mix of both electronic types – typically 33% metallic and 67% semiconducting.
The researchers dispersed unsorted tubes in water using two surfactants. Because the surfactant wraps around the tubes in a different way depending on their electronic type, the metallic and semiconducting tubes end up with different buoyant densities and can therefore be separated using DGU.
After sorting the tubes into metallic and semiconducting batches, the team processed them into freestanding films using vacuum filtration. The films were subsequently used as the cathodes in lithium-ion half-cell batteries with the lithium metal as the anode. The researchers measured properties such as cell capacity, charge-transfer (or Coulomb) efficiency, and battery cycling rates of devices made from each type of tube to determine how easily each one took up lithium. These studies were augmented with theoretical calculations.
Hersam and colleagues found that metallic SWCNTs accommodate lithium much more efficiently than their semiconducting counterparts. Another important discovery was that, if made denser, the semiconducting SWCNT films also begin to take up lithium at levels that are comparable to metallic SWCNTs. This is because lithium is more easily accommodated at the junctions between tubes, says Hersam.
That the Universe is largely composed of a cosmic web consisting of narrow filaments upon which galaxies and intergalactic gas and dust are concentrated has been known for more than a decade. While a great deal of evidence for this has accumulated, visual evidence has been difficult to find. Astronomers have now photographed what appears to be a segment of a cosmic filament stimulated into fluorescence by irradiation from a nearby quasar.
The filaments of the cosmic web are difficult to see visually. They consist primarily of dark matter and intergalactic gas and dust, none of which have a visible signature detectable across billions of light years. As a result, our knowledge of filaments primarily comes from gravitational lensing studies, radio observations, and x-ray telescopes.
Now a team, led by researchers at the University of California, Santa Cruz (UCSC), has found an unusual configuration of celestial objects that appears to make visible a part of a filament that is ten billion light years distant. The section of the filament that is visible takes the form of a huge asymmetric nebula of diffuse intergalactic gas.
Normally this gas would not emit significant amounts of light, but in this case the intergalactic gas is being irradiated by extreme UV light from a nearby quasar; the active center of a galaxy. This irradiation ionized the gas (mostly consisting of atomic hydrogen), which then emits the characteristic light of atomic hydrogen (Lyman-alpha radiation) when the ionized atoms regain their electrons. When redshift (z~2.27) is taken into account, the Lyman-alpha radiation appears to our instruments as a violet glow.
The map above is also a product of the SDSS, which used a 2.5 meter telescope to image and determine redshift (and thereby distance) for galaxies in the cosmic vicinity of the Milky Way galaxy. It includes galaxies and quasars located in a thin slice of the sky above the Earth's equator out to a distance of two billion light years. One's first impression is of a slice through a foam of luminous bodies that lay on the boundary of huge voids.
Rather solid evidence also exists for the existence of filaments with a goodly share of dark matter, as illustrated in the above figure of just such a dark matter filament. This filament stretches about sixty million light years between the galaxy clusters Abell 222 and 223. X-ray emissions from the filament suggest that nearly 10 percent of the filament's mass consists of hot gas. This filament comprises at least dark matter and intergalactic gas.
The team published a report in the January 19, 2014, issue of Nature of their discovery of a rather unusual configuration of celestial objects in the early history of the Universe (about three billion years after the Big Bang) that provides additional evidence for the existence of the cosmic web.
A black hole with extremely powerful jets has been found in the nearby galaxy Messier 83 (M83) by a team of Australian and American researchers, as we report in the journal Science today.
Black holes are by definition invisible, but when matter falls towards (and then into) them, they turn into a very efficient class of engines.
Chuck in some fuel (any kind of matter will do) and you get a huge amount of energy extracted from it as it falls into the gravitational field of the hole; eventually, the infalling gas crosses the horizon and is lost forever (or not) to our view.
If a car engine could be as energy efficient as a black hole, we could drive to Saturn and back with one litre of petrol (based on typical gasoline combustion efficiency of 45 MJ/kg, compared with the energy released by accretion onto a black hole, about 10 billion MJ/kg).
We don't have black-hole-powered cars because nobody knows how to make pocket-size black holes on Earth. But Nature has found ways of making black holes and using them as compact sources of energy. The most energetic or most explosive sources in the universe (such as quasars and gamma-ray bursts) are powered by the gravitational field of black holes, not by nuclear fusion which powers the sun and all other stars.
The more we explore the cosmos around us, the more evidence we find of active black holes and the effect they have on their surroundings. The newly-identified object in M83 (named MQ1, as the most energetic microquasar in M83) is the latest, striking example.
Measuring the radiative luminosity is relatively straightforward, thanks to orbiting X-ray telescopes such as Chandra, XMM-Newton and Swift.
Measuring the jet power is more tricky. Jets eventually slam into the surrounding interstellar gas, shocking and heating it, so a black hole with powerful jets tends to be surrounded by an expanding, elongated "bubble" of hot ionised gas and free electrons. By measuring the size and luminosity (both the optical and radio emission) of this bubble, we estimate the power of the jets and for how long they have been switched on. This is precisely what we did for MQ1 in the M83 galaxy.
We inferred a huge jet power, a few million times higher than the total power of the sun, but similar to a few other black holes discovered in nearby galaxies over the past decade.
So, MQ1 is not a total oddity or an experimental glitch; but it is the only one in its class (so far) for which we can also constrain the mass of the black hole, via X-ray measurements of the radiation emitted by the infalling gas.
Have you ever wondered why your laptop or smartphone feels warm when you're using it? That heat is a byproduct of the microprocessors in your device using electric current to power computer processing functions — and it is actually wasted energy.
Now, a team led by researchers from the UCLA Henry Samueli School of Engineering and Applied Science has made major improvements in computer processing using an emerging class of magnetic materials called "multiferroics," and these advances could make future devices far more energy-efficient than current technologies.
With today's device microprocessors, electric current passes through transistors, which are essentially very small electronic switches. Because current involves the movement of electrons, this process produces heat — which makes devices warm to the touch. These switches can also "leak" electrons, making it difficult to completely turn them off. And as chips continue to get smaller, with more circuits packed into smaller spaces, the amount of wasted heat grows.
The UCLA Engineering team used multiferroic magnetic materials to reduce the amount of power consumed by "logic devices," a type of circuit on a computer chip dedicated to performing functions such as calculations. A multiferroic can be switched on or off by applying alternating voltage — the difference in electrical potential. It then carries power through the material in a cascading wave through the spins of electrons, a process referred to as a spin wave bus.
A spin wave can be thought of as similar to an ocean wave, which keeps water molecules in essentially the same place while the energy is carried through the water, as opposed to an electric current, which can be envisioned as water flowing through a pipe, said principal investigator Kang L. Wang, UCLA's Raytheon Professor of Electrical Engineering and director of the Western Institute of Nanoelectronics (WIN).
"Spin waves open an opportunity to realize fundamentally new ways of computing while solving some of the key challenges faced by scaling of conventional semiconductor technology, potentially creating a new paradigm of spin-based electronics," Wang said.
The UCLA researchers were able to demonstrate that using this multiferroic material to generate spin waves could reduce wasted heat and therefore increase power efficiency for processing by up to 1,000 times. Their research is published in the journal Applied Physics Letters.
A team of researchers working at the university of Notre Dame has discovered a whole new group of quasicrystals. In their paper published in the journal Nature, the team describes how they accidently created a new kind of quasicrystal as part of a series of experiments designed to learn more about electron distribution in ferrocenecarboxylic acids.
Quasicrystals are groups of molecules bonded together in structures that resemble crystals in that they are organized, but unlike crystals, the structures are not nearly as uniform. In fact, they are quite the opposite—though they are locally symmetric, they lack any sort of long distance periodicity. Because of their chaotic nature, quasicrystals tend to feel slippery to the touch, which is why they have been used to coat the surface of non-stick frying pans. The first quasicrystal was made, also by accident, in 1982, by Daniel Shechtman (who later won a Nobel prize for his work). Since then many more of them have been made in various labs, (one was even found to exist in a meteorite) though most of them have had one thing in common, they were all formed from two or three metal alloys.
In this latest discovery, the quasicrystals self-formed after the researchers placed a layer of iron containing molecules of ferrocenecarboxylic acid on top of a gold surface. The team was expecting to see a linear group of stable molecules pairing up as dimers, but instead were surprised to find that they had formed into five sided rosettes—it was the rosettes that pushed other molecules into bonding forming crystalline shapes, resulting in the formation of 2D quasicrystals that took the form of several different shapes: stars, boats, pentagons, rhombi, etc., all repeated in haphazard fashion.
In studying the quasicrystals using scanning tunnelling microscopy, the researchers found that they were held together by weak hydrogen bonds rather that the strong ionic bonds found in other such molecules. Weak hydrogen bonds are generally more common in organic molecules that exhibit complex structures.
In their paper, the researchers suggest their discovery might lead to the creation or discovery of many other similar types of quasicrystals, though it's still not clear to what use they might be put.
When a person suffers a broken bone, treatment calls for the surgeon to insert screws and plates to help bond the broken sections and enable the fracture to heal. These “fixation devices” are usually made of metal alloys.
But metal devices may have disadvantages: Because they are stiff and unyielding, they can cause stress to underlying bone. They also pose an increased risk of infection and poor wound healing. In some cases, the metal implants must be removed following fracture healing, necessitating a second surgery. Resorbable fixation devices, made of synthetic polymers, avoid some of these problems but may pose a risk of inflammatory reactions and are difficult to implant.
Now, using pure silk protein derived from silkworm cocoons, a team of investigators from Tufts University School of Engineering and Beth Israel Deaconess Medical Center (BIDMC) has developed surgical plates and screws that may not only offer improved bone remodeling following injury, but importantly, can also be absorbed by the body over time, eliminating the need for surgical removal of the devices.
The findings, demonstrated in vitro and in a rodent model, are described in the March 4 issue of Nature Communications. “Unlike metal, the composition of silk protein may be similar to bone composition,” says co-senior author Samuel Lin, MD, of the Division of Plastic and Reconstructive Surgery at BIDMC and Associate Professor of Surgery at Harvard Medical School. “Silk materials are extremely robust. They maintain structural stability under very high temperatures and withstand other extreme conditions, and they can be readily sterilized.”
A new species of dinosaur found in Portugal likely used brute force to take down prey, a new study says. Torvosaurus gurneyi, perhaps the biggest predatory dinosaur yet found in Europe, was an especially strong carnivore that likely used its four-inch-long (ten-centimeter-long), blade-shaped teeth and sharp-clawed forearms to rip into its prey.
The 32-foot-long (10-meter-long) beast roamed the Iberian Peninsula—home to modern-day Spain, Portugal, Andorra, and parts of France—about 150 million years ago during the late Jurassic period.
Christophe Hendrickx, a Ph.D. student at the New University of Lisbon in Portugal, discovered the giant while studying bones believed to belong to Torvosaurus tanneri, a related species that lived in North America's Rocky Mountain region around the same time. When the continents were connected as part of the supercontinent Pangaea, dinosaurs could potentially have migrated from North America to Europe or vice versa. But upon closer inspection, these bones—taken from the fossil-rich Lourinhã Formation in west-central Portugal—didn't look like T. tanneri. For one, the upper jaw had fewer teeth, this bone and the tail vertebrae differed—all suggesting that Hendrickx and supervisor Octávio Mateushad revealed a new species.
Discovering planets outside our Solar System has raised hopes that we may one day contact alien lifeforms. But will this ever happen?
Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” So said sci-fi author Arthur C Clarke. We’ve been fascinated by the idea life may exist elsewhere, and for over 50 years the Search for Extra Terrestrial Intelligence (Seti) has been scanning the galaxy for messages from an alien civilisation to no avail.
But the discovery of planets outside our solar system, or exoplanets, has raised hopes that efforts to contact alien lifeforms may one day succeed. BBC’s Horizon joined the planet hunters who discovered a new world called Gliese 581 c. To date, it is one of the most Earth-like planets found around another star, and it may have habitats capable of supporting life.
For the first time, a team of American astronomers has used near-infrared spectroscopy to directly detect water vapor in the atmosphere of a gas giant planet in close orbit around Tau Bootis — a bright star in Bootes that may have even helped Odysseus home from Troy.
But not even Odysseus could have imagined that 21st century spectroscopy would be teasing data from the hellishly hot atmosphere of a 3.8 Jupiter-mass planet around a star only 50 light years from earth.
Water has been detected in the atmospheres of several extrasolar planets using other techniques. However, this detection via thermal emission, as reported in The Astrophysical Journal Letters, enables astronomers to directly characterize the atmospheres of such “hot Jupiters.”
“This discovery of water on Tau Bootis b is absolutely wonderful,” said longtime extrasolar planet hunter Geoff Marcy, an astronomer at the University of California at Berkeley, who along with astronomer Paul Butler, first discovered the planet in 1996.
And it’s all the more “incredible,” says Marcy, considering that only 18 years ago, he and colleagues still thought it “a miracle” to be able to indirectly detect any such extrasolar Jupiter-mass planets, much less study their atmospheres.
Penn State University astronomer Chad Bender, one of the paper’s co-authors, says this is the first time anyone has detected water in a non-transiting planet. That is, a planet having its atmosphere probed by the background glow from its parent star.
That’s important, says Bender, because the population of non-transiting extrasolar planets is much larger than those that from our line of sight appear to transit across the face of their parent stars.
Scientists are mapping out a mission to the metallic asteroid Psyche, which is thought to be the exposed iron core of a protoplanet. The proposed mission would reveal insights about planet formation and afford the first-ever good look at a metal world.
Discovered in 1852, the main-belt asteroid Psyche is unique in that it is believed to be the exposed core of an ancient protoplanet that never completely formed, or whose rocky outer layers were destroyed. It is the most massive known M-type (metallic) asteroid, with a composition of 90-percent iron and nickel, and 10-percent silicate rock — similar to Earth's core.
The Earth's nickel-iron core is a dynamo that creates a massive magnetic field around the planet. Scientists believe Psyche also generates a magnetic field, perhaps nearly as strong as that of Earth.
Psyche is an irregularly-shaped asteroid measuring about 150 miles (240 kilometers) along its largest side. This makes it the 10th or 11th largest known asteroid (sizes are not known precisely, preventing exact rankings). The largest asteroids, including Ceres and Vesta, are protoplanets – survivors from the early formation of the solar system.
A new technology developed at the Massachusetts General Hospital Center for Systems Biology allows simultaneous analysis of hundreds of cancer-related protein markers from miniscule patient samples gathered through minimally invasive methods.
Minimally invasive techniques – such as fine-needle aspiration or circulating tumor cell analysis – are increasingly employed to track treatment response over time in clinical trials, as such tests can be simple and cheap to perform. Fine needle aspirates are also much less invasive than core biopsies or surgical biopsies, since very small needles are used. The challenge has been to comprehensively analyze the very few cells that are obtained via this method. "What this study sought to achieve was to vastly expand the information that we can obtain from just a few cells," explains Cesar Castro, MD, of the MGH Cancer Centerand CSB, a co-author of the Science Translational Medicine paper. "Instead of trying to procure more tissue to study, we shrank the analysis process so that it could now be performed on a few cells.”
Up until now, pathologists have been able to examine only a handful of protein markers at a time for tumor analyses. But with this new technology, researchers at CSB have demonstrated the ability to look at hundreds of markers simultaneously down to the single-cell level. "We are no longer limited by the scant cell quantities procured through minimally invasive procedures," says Castro. "Rather, the bottleneck will now be our own understanding of the various pathways involved in disease progression and drug target modulation."
The novel method centers on an approach known as DNA-barcoded antibody sensing, in which unique DNA sequences are attached to antibodies against known cancer marker proteins. The DNA 'barcodes' are linked the antibodies with a special type of glue that breaks apart when exposed to light. When mixed with a tumor sample, the antibodies seek out and bind to their targets; then a light pulse releases the unique DNA barcodes of bound antibodies that are subsequently tagged with fluorescently-labeled complementary barcodes. The tagged barcodes can be detected and quantified via imaging, revealing which markers are present in the sample.
After initially demonstrating and validating the technique's feasibility in cell lines and single cells, the team went on to test it on samples from patients with lung cancer. The technology was able to reflect the great heterogeneity – differences in features such as cell-surface protein expression – of cells within a single tumor and to reveal significant differences in protein expression between tumors that appeared identical under the microscope. Examination of cells taken at various time points from participants in a clinical trial of a targeted therapy drug revealed marker patterns that distinguished those who did and did not respond to treatment.
Plants are also able to make complex decisions. At least this is what scientists have concluded from their investigations on Barberry (Berberis vulgaris), which is able to abort its own seeds to prevent parasite infestation. Approximately 2000 berries were collected during this study from different regions of Germany, examined for signs of piercing and then cut open to examine any infestation by the larvae of the tephritid fruit fly (Rhagoletis meigenii).
This parasite punctures the berries in order to lay its eggs inside them. If the larva is able to develop, it will often feed on all of the seeds in the berry. A special characteristic of the Barberry is that each berry usually has two seeds and that the plant is able to stop the development of its seeds in order to save its resources. This mechanism is also employed to defend it from the tephritid fruit fly. If a seed is infested with the parasite, later on the developing larva will feed on both seeds. If however the plant aborts the infested seed, then the parasite in that seed will also die and the second seed in the berry is saved.
When analysing the seeds, the scientists came across a surprising discovery: "the seeds of the infested fruits are not always aborted, but rather it depends on how many seeds there are in the berries", explains Dr. Katrin M. Meyer, who analysed the data at the UFZ and currently works at the University of Goettingen. If the infested fruit contains two seeds, then in 75 per cent of cases, the plants will abort the infested seeds, in order to save the second intact seed. If however the infested fruit only contains one seed, then the plant will only abort the infested seed in 5 per cent of cases. The data from fieldwork were put into a computer model which resulted in a conclusive picture.
Using computer model calculations, scientists were able to demonstrate how those plants subjected to stress from parasite infestation reacted very differently from those without stress. "If the Barberry aborts a fruit with only one infested seed, then the entire fruit would be lost. Instead it appears to 'speculate' that the larva could die naturally, which is a possibility. Slight chances are better than none at all", explains Dr. Hans-Hermann Thulke from the UFZ. "This anticipative behaviour, whereby anticipated losses and outer conditions are weighed up, very much surprised us. The message of our study is therefore that plant intelligence is entering the realms of ecological possibility."
But how does the Barberry know what is in store for it after the tephritid fruit fly has punctured a berry? It is still unclear as to how the plant processes information and how this complex behaviour was able to develop over the course of evolution. The Oregon grape that is closely related to the Barberry has been living in Europe for some 200 years with the risk of being infested by the tephritid fruit fly and yet it has not developed any such comparable defence strategy. These new insights shed some light on the underestimated abilities of plants, while at the same time bringing up many new questions.
(Phys.org) —When the sun sets on a remote desert outpost and solar panels shut down, what energy source will provide power through the night? A battery, perhaps, or an old diesel generator? Perhaps something strange and new.
Physicists at the Harvard School of Engineering and Applied Sciences (SEAS) envision a device that would harvest energy from Earth's infrared emissions into outer space.
Heated by the sun, our planet is warm compared to the frigid vacuum beyond. Thanks to recent technological advances, the researchers say, that heat imbalance could soon be transformed into direct-current (DC) power, taking advantage of a vast and untapped energy source.
Their analysis of the thermodynamics, practical concerns, and technological requirements will be published this week in the Proceedings of the National Academy of Sciences.
"It's not at all obvious, at first, how you would generate DC power by emitting infrared light in free space toward the cold," says principal investigator Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at Harvard SEAS. "To generate power by emitting, not by absorbing light, that's weird. It makes sense physically once you think about it, but it's highly counterintuitive. We're talking about the use of physics at the nanoscale for a completely new application."
A team of interdisciplinary researchers have created "smart" holograms that can monitor health conditions or diagnose diseases, by changing color in the presence of disease indicators in a person's breath or bodily fluids. When developed into a portable medical test, these responsive holograms could make testing for medical conditions and monitoring one's health very easy, the scientists claim.
A person would just have to check the hologram's color against a chart or use a camera phone to read the results. As these holographic sensors don't require batteries, electricity or lasers to function, it's possible to create inexpensive portable tests for healthcare workers to use or people to self-administer, that could help them potentially diagnose diseases in their earliest stages.
"We often see holograms on banknotes, credit cards, as security features, or artwork," Ali Yetisen, a PhD student at the University of Cambridge, UK, who led the research, tells Gizmag. "However, these type of holograms do not response when they encounter a health condition indicator such as glucose or blood electrolytes. We have developed techniques to make these holograms 'smart,' so that they can respond to a wide range of disease markers."
The holographic sensors are made out of hydrogels (a highly absorbent material) that are doped with silver nanoparticles. These silver nanoparticles are then organized into three-dimensional holograms of predetermined shapes using a multi-megawatt laser. The final sensors resemble the iridescent hardened forewings of beetles, and normally diffract light in a green color.
However, when the holographic sensor is exposed to a person's breath, urine, tears or a drop of their blood or saliva, the hydrogel in the sensor, which is sensitive to specific disease indicators, reacts if any of them are present. The hydrogel either swells or shrinks, causing a change in the hologram's color in the entire visible spectrum. It's the first time, the researchers claim, that they've been able to achieve such a result with a colorimetric sensor.
"It's pretty much like a butterfly wing," says Dr. Haider Butt, a Lecturer in Micro Engineering and Nanotechnology, at the University of Birmingham and a co-author of the study. "But this is a butterfly wing that changes color depending on the solution we dip it in."
Three new planets classified as habitable-zone super-Earths are amongst eight new planets discovered orbiting nearby red dwarf stars by an international team of astronomers from the UK and Chile.
The study identifies that virtually all red dwarfs, which make up at least three quarters of the stars in the Universe, have planets orbiting them.
The research also suggests that habitable-zone super-Earth planets (where liquid water could exist and making them possible candidates to support life) orbit around at least a quarter of the red dwarfs in the Sun's own neighbourhood.
These new results have been obtained from analysing data from two high-precision planet surveys – the HARPS (High Accuracy Radial Velocity Planet Searcher) and UVES (Ultraviolet and Visual Echelle Spectrograph) – both operated by the European Southern Observatory in Chile. By combining the data, the team was able to detect signals that were not strong enough to be seen clearly in the data from either instrument alone.
ZFN, TALEN, and CRISPR/Cas systems help scientists dissect the vast amount of information accumulated through the Genomic Revolution.
The Genomic Revolution has promised to advance medicine and biotechnology by providing scientists with enormous amounts of data that can be converted into useful information.
Over 10 years ago, the Human Genome Project produced the first draft of the more than 3 billion base pairs of DNA that make up the genetic code in each of our cells.
More recent efforts like the 1000 Genomes and HapMap Projects have since focused on identifying the differences within these billions of base pairs of DNA between individuals, while genome-wide association studies have pinpointed specific sequences that determine health and disease. The ENCODE Project and other studies have annotated chromatin states, regulatory elements, transcription factor binding sites, and other epigenetic states throughout the genome.
Dozens of other species have since undergone similar analyses, with the number of sequenced genomes continuously growing. Collectively, these efforts have generated an incredibly rich source of data that promises to aid our understanding of the function and evolution of any genome. However, until recently, scientists have been lacking the tools necessary to interrogate the structure and function of these elements.
While conventional genetic engineering methods could be used to add extra genes to cells, they cannot be easily used to modify the sequences or control the expression of genes that already exist within these genomes. These types of tools are necessary to determine not only the function of genes, but also the role of genetic variants and regulatory elements. They can also be used to overcome longstanding challenges in the field of gene therapy. Without these technologies, it has been difficult—and in some cases impossible—for scientists to capitalize on the Genomic Revolution.