Forgot your password?

+ - Mathematicians Solve The Topological Mystery Behind The "Brazuca" Soccer Ball

Submitted by KentuckyFC
KentuckyFC (1144503) writes "In the 1970 World Cup in Mexico, teams used a new kind of ball called the Telstar made from 12 black pentagonal panels and 20 white hexagonal panels. This ball has icosahedral symmetry and its own molecular analogue in the form of C60, the famous soccer ball-shaped fullerene. In 2006, a new ball called the TeamGeist was introduced at the World Cup in Germany. This was made of 14 curved panels that together gave it tetrahedral symmetry. This also had a molecular analogue with tetrahedral symmetry among the fullerenes. Now teams at the current World Cup in Brazil are playing with yet another design: the Brazuca, a ball constructed from six panels each with a four-leaf clover shape that knit together like a jigsaw to form a sphere. This has octahedral symmetry. But here's question that has been puzzling chemists, topologists fans: is there a molecular analogue of the Brazuca? Or put another way, can fullerenes have octahedral symmetry? Now a pair of mathematicians have finally solved this problem. They've shown that fullerenes can indeed have octahedral symmetry just like the Brazuca, although in addition to hexagonal and pentagonal carbon rings, the ball-shaped molecules must also have rings of 4 and 8 carbon atoms. The next stage is to actually synthesis one of these fullerenes, perhaps something to keep chemists occupied until the 2018 World Cup in Russia."

+ - Tractor Beam Created Using Water Waves

Submitted by KentuckyFC
KentuckyFC (1144503) writes "The idea that light waves can push a physical object is far from new. But a much more recent idea is that a laser beam can also pull objects like a tractor beam. Now a team of Australian physicists has used a similar idea to create a tractor beam with water waves that pulls floating objects rather than pushes them. Their technique is to use an elongated block vibrating on the surface of water to create a train of regular plane waves. When the amplitude of these waves is small, they gradually push the surface of the water along, creating a flow that pushes floating objects with it. However, when the amplitude increases, the waves become non-linear and begin to interact with each other in a complex way. This sets up a flow of water on the surface in the opposite direction to the movement of the waves. The result is that floating objects--ping pong balls in the experiment--are pulled towards the vibrating block, like a tractor beam."

+ - New Class of Stars Are Totally Metal, Says Astrophysicist->

Submitted by KentuckyFC
KentuckyFC (1144503) writes "Stars form when clouds of gas and dust collapse under their own gravity, generating enough heat and pressure to fuse the atoms inside them together. When this cloud of dust and gas is the remnants of a supernova, it can contain all kinds of heavy elements in addition to primordial hydrogen, helium and lithium. Now one astrophysicist has calculated that a recently discovered phenomenon of turbulence, called preferential concentration, can profoundly alter star formation. He points out that turbulence is essentially vortices rotating on many scales of time and space. On certain scales, the inertial forces these eddies create can push heavy particles into the calmer space between the vortices, thereby increasing their concentration. In giant clouds of interstellar gas, this concentrates heavy elements, increasing their gravitational field, attracting more mass and so on. The result is the formation of a star that is made entirely of heavy elements rather than primordial ones. Astrophysicists call the amount of heavy elements in a star its "metallicity". Including preferential concentration in the standard model of star formation leads to the prediction that 1 in 10,000 stars should be totally metal. Now the race is on to find the first of this new class of entirely metal stars."
Link to Original Source

+ - Secret Of The Banjo's Unique Sound Discovered By Nobel Prize-Winning Physicist

Submitted by KentuckyFC
KentuckyFC (1144503) writes "The banjo is a stringed instrument that produces a distinctive metallic sound often associated with country, folk and bluegrass music. It is essentially a drum with a long neck. Strings are fixed at the end of the neck, stretched across the drum and fixed on the other side. They are supported by a bridge that sits on the drum membrane. While the instrument is straightforward in design and the metallic timbre easy to reproduce, acoustics experts have long puzzled over exactly how the instrument produces its characteristic tones. Now David Politzer, who won the Nobel prize for physics in 2004, has worked out the answer. He says the noise is the result of two different kinds of vibrations. First there is the vibration of the string, producing a certain note. However, the drum also vibrates and this pushes the bridge back and forth causing the string to stretch and relax. This modulates the frequency of the note. When frequency of this modulation is below about 20 hertz, it creates a warbling effect. Guitar players can do the same thing by pushing a string back and forth after it is plucked. But when the modulating frequency is higher, the ear experiences it as a kind of metallic crash. And it is this that gives the banjo its characteristic twang. If you're in any doubt, try replacing the drum membrane with a piece of wood and the twang goes away. That's because the wood is stiffer and so does not vibrate to the same extent. Interesting what Nobel prize-winning physicists do in their spare time."

+ - Human Language Is Biased Towards Happiness, Say Computational Linguists

Submitted by KentuckyFC
KentuckyFC (1144503) writes "The idea that people tend to use positive words more often the negative ones is now known as the Pollyanna hypothesis, after a 1913 novel by Eleanor Porter about a girl who tries to find something to be glad about in every situation. But although widely known, attempts to confirm the hypothesis have all been relatively small studies and so have never been thought conclusive. Now a group of researchers at Computational Story Lab at the University of Vermont have repeated this work on a corpus of 100,000 words from 24 languages representing different cultures around the world. They first measured the frequency of words in each language and then paid native speakers to rate how they felt about each word on a scale ranging from the most negative or sad to the most positive or happy. The results reveal that all the languages show a clear bias towards positive words with Spanish topping the list, followed by Portuguese and then English. Chinese props up the rankings as the least happy. They go on to use these findings as a ‘lens’ through which to evaluate how the emotional polarity changes in novels in various languages and have set up a website where anybody can explore novels in this way. The finding that human language has universal positiver bias could have a significant impact on the relatively new science of sentiment analysis on social media sites such as Twitter. If there is a strong bias towards positive language in the first place, and this changes from one language to another, then that is obviously an important factor to take into account."

+ - Evidence Of A Correction To The Speed of Light

Submitted by KentuckyFC
KentuckyFC (1144503) writes "In the early hours of the morning on 24 February 1987, a neutrino detector deep beneath Mont Blanc in northern Italy picked up a sudden burst of neutrinos. Three hours later, neutrino detectors at two other locations picked up a second burst. These turned out to have been produced by the collapse of the core of a star in the Large Magellanic Cloud that orbits our galaxy. And sure enough, some 4.7 hours after this, astronomers noticed the tell-tale brightening of a blue supergiant in that region, as it became a supernova, now known as SN1987a. But why the delay of 7.7 hours from the first burst of neutrinos to the arrival of the photons? Astrophysicists soon realised that since neutrinos rarely interact with ordinary matter, they can escape from the star's core immediately. By contrast, photons have to diffuse through the star, a process that would have delayed them by about 3 hours. That accounts for some of the delay but what of the rest? Now one physicist has the answer--the speed of light through space requires a correction. As a photon travels through space, there is a finite chance that it will form an electron-positron pair. This pair exists for only a brief period of time and then goes on to recombine creating another photon which continues along the same path. This is a well-known process called vacuum polarisation. The new idea is that the gravitational potential of the Milky Way must influence the electron-positron pair because they have mass. This changes the energy of the virtual electron-positron pair, which in turn produces a small change in the energy and speed of the photon. And since the analogous effect on neutrinos is negligible, light will travel more slowly than them through a gravitational potential. According to the new calculations which combine quantum electrodynamics with general relativity, the change in speed accounts more or less exactly for the mysterious time difference. Voila!"

+ - First Movie Of An Entire Brain's Neuronal Activity

Submitted by KentuckyFC
KentuckyFC (1144503) writes "One of the goals of neuroscience is to understand how brains process information and generate appropriate behaviour. A technique that is revolutionising this work is optogenetics--the ability to insert genes into neurons that fluoresce when the neuron is active. That works well on the level of single neurons but the density of neurons in a brain is so high that it has been impossible to tell them apart when they fluoresce. Now researchers have solved this problem and proved it by filming the activity in the entire brain of a nematode worm for the first time and making the video available. Their solution comes in two parts. The first is to ensure that the inserted genes only fluoresce in the nuclei of the neurons. This makes it much easier to tell individual neurons in the brain apart. The second is a new techniques that scans the entire volume of the brain at a rate of 80 frames per second, fast enough to register all the neuronal activity within it. The researchers say their new technique should allow bigger brains to be filmed in the near future opening up the potential to study how various creatures process information and trigger an appropriate response for the first time."

+ - The Computer Security Threat From Ultrasonic Networks

Submitted by KentuckyFC
KentuckyFC (1144503) writes "It’s easy to imagine that computer security experts have a good idea of the kind of attacks they are likely to experience in future. They may not know the details but they should at least know the channels that are vulnerable so that they can allocate security resources accordingly. Perhaps not! Security researchers in Germany have demonstrated an entirely new way to attack computer networks and steal information without anybody knowing. The new medium of attack is ultrasonic sound. It relies on software that uses the built-in speakers on a laptop to broadcast at ultrasonic frequencies while nearby laptops listen out for the transmissions and pass them on, a set up known as a mesh network. The team has tested this kind of attack on a set of Lenovo T400 laptops infected with key-logging software. They say it is possible to transmit ultrasonic signals covertly at data rates of 20 bits per second at distances of up to 20 metres in an office environment. Interestingly, the team created the covert system by adapting a protocol designed for underwater acoustic communication. They've also tested various strategies for defeating this kind of attack. An obvious option is to disable all speakers and microphones but this also prevents ordinary activities such as VOIP communication. Instead, they suggest filtering the audio signals to prevent ultrasonic transmissions or converting them into an audible frequency."

+ - The Emerging Revolution In The Science Of Deflector Shields

Submitted by KentuckyFC
KentuckyFC (1144503) writes "One curious feature on the Moon's surface are “lunar swirls”, wisp-like regions that are whiter than surrounding areas and that, until recently, astronomers could not explain. But one team of physicists recently showed that these areas are protected by weak magnetic fields that deflect high energy particles from the Sun and so prevent the darkening effect this radiation has. The problem they had to solve was how a weak field could offer so much protection, when numerous studies of long duration spaceflight have shown that only very powerful fields can act like radiation shields. The team now says that these previous studies have failed to take into account an important factor: the low density plasma that exists in space. It turns out that this plasma is swept up by a weak magnetic field moving through space, creating a layer of higher density plasma. That's important because the separation of charge within this layer creates an electric field. And it is this field that deflects the high energy particles from the Sun. That explains the lunar swirls but it also suggests that the same effect could be exploited to protect astronauts on long duration missions to the moon, to nearby asteroids and beyond. This team has now produced the first study of such a shield and how it might work. Their shield would use superconducting coils to create a relatively weak field only when it is needed, during solar storms, for example. And it would create a plasma by pumping xenon into the vacuum around the vehicle, where it would be ionised by UV light. The entire device would weigh around 1.5 tonnes and use about 20 KW of power. That's probably more than mission planners could currently accommodate but it is significantly less than the science fiction-type power requirements of previous designs. And who knows what other tricks of plasma physics engineers might be able to exploit to refine this design. All of a sudden, long duration space flight looks a little more feasible."

+ - Wikipedia Mining Algorithm Reveals The Most Influential People In History 1

Submitted by KentuckyFC
KentuckyFC (1144503) writes "In 1978, the American researcher Michael Hart published "The 100: A Ranking of the Most Influential Persons in History", a book that became an international best seller. Since then, various others have published similar lists. But all suffer the same drawback: they are subjective list ultimately influenced by numerous cultural factors. Now data scientists have come up with a way to extract an objective list of the 100 most influential people in history using the network of links between biographical articles on Wikipedia and how they vary between 24 different language editions, including English, Chinese, Russian Arabic and so on. The researchers assume that people who are highly ranked in different language editions are influential across both language cultures and that the more appearances they make in different language editions, the more influential they are. But the actual ranking is done by PageRank-like algorithms that consider a biographical article important if it is pointed to by other important articles. The resulting lists of the most influential men and women might surprise. The top PageRanked individual is Carl Linnaeus, the 18th century Swedish botanist who developed the modern naming scheme for plants and animals, followed by Jesus. The top PageRanked women are: Elizabeth II followed by Mary (mother of Jesus). For comparison, just under half of the top 100 most influential also appear in Hart's 1978 book. But this is just the beginning. By counting the individuals from one culture that influence other cultures, the team is able to work out which cultures have dominated others. And by looking only at people born before certain dates, they can see how the influence of different cultures has waxed and waned throughout 35 centuries of recorded history."

+ - Astronomers Solve Puzzle Of Mysterious Streaks In Radio Images Of The Sky 2

Submitted by KentuckyFC
KentuckyFC (1144503) writes "Back in 2012, astronomers constructed an array of 256 radio antennas in the high deserts of New Mexico designed to listen for radio waves produced by gamma ray bursts, one of the most energetic phenomena in universe and thought to be associated with the collapse of a rapidly rotating stars to form neutron stars and black holes. The array generates all sky images of signals produced in the 25 MHz to 75 MHz region of the spectrum. But when researchers switched it on, they began to observe puzzling streaks across the sky that couldn't possibly be generated by gamma ray bursts. One source left a trail covering more than 90 degrees of the sky in less than 10 seconds. This trail then slowly receded to an endpoint which glowed for around 90 seconds. Now the first study of these transient radio signals has discovered that they are almost certainly produced by fireballs as they burn up after entering the Earth's atmosphere. The conclusion comes after the researchers were able to match several of the radio images with visible light images of fireballs gathered by NASA's All Sky Fireball Network. That solves the mystery but not without introducing another to keep astrophysicists busy in future. The question they're scratching their heads over now is how the plasma trails left by meteors can emit radio waves at this frequency."

+ - Geophysicists Discover How Rocks Produce Magnetic Pulses

Submitted by KentuckyFC
KentuckyFC (1144503) writes "Since the 1960s, geophysicists have known that some earthquakes are preceded by ultra-low frequency magnetic pulses that increase in number until the quake takes place. But this process has always puzzled them: how can rocks produce magnetic pulses? Now a group of researchers has worked out what's going on. They say that rocks under pressure can become semiconductors that produce magnetic pulses under certain circumstances. When igneous rocks form in the presence of water, they contain peroxy bonds with OH groups. Under great temperature and pressure, these bonds break down creating electron-holes pairs. The electrons become trapped at the site of the broken bonds but the holes are free to move through the crystal structure. The natural diffusion of these holes through the rock creates p and n regions just like those in doped semiconductors. And the boundary between these regions behaves like the p-n junction in a diode, allowing current to flow in one direction but not the other. At least not until the potential difference reaches a certain value when the boundary breaks down allowing a sudden increase in current. It is this sudden increase that generates a magnetic field. And the sheer scale of this process over a volume of hundreds of cubic metres ensures that these magnetic pulses have an extremely low frequency that can be detected on the surface. The new theory points to the possibility of predicting imminent earthquakes by triangulating the position of rocks under pressure by searching for the magnetic pulses they produce (although significantly more work needs to be done to characterise the process before then)."

+ - Why David Deutsch's New Theory of Reality is Deeper Than Quantum Mechanics

Submitted by KentuckyFC
KentuckyFC (1144503) writes "In 1948, the Bell Labs mathematician and engineer Claude Shannon published The Mathematical Theory of Communication (pdf). In it, he laid out the basic process of communication and formally introduced ideas such as information, the role of transmitters and receivers as well as the idea of a channel and its capacity to carry information. This theory now forms the basis of all digital communication so it's no exaggeration to say that it has been hugely influential. By contrast, no equivalent theory exists for quantum information, despite decades of work by quantum theorists. That could all change now thanks to the work of David Deutsch, a theoretical physicist, who has developed a theory that links classical and quantum information using a deeper theoretical framework. Deutsch's new approach is called constructor theory and it turns the conventional approach to physics on its head. Physicists currently ply their trade by explaining the world in terms of initial conditions and laws of motion. This leads to a distinction between what happens and what does not happen. By contrast, Deutsch’s new fundamental principle is that all laws of physics are expressible entirely in terms of the physical transformations that are possible and those that are impossible. In other words, the laws of physics do not tell you what is possible and impossible, they are the result of what is possible and impossible. So reasoning about the physical transformations that are possible and impossible leads to the laws of physics. He uses this approach to develop a number of principles that all physical laws must follow, both those that are known and those that are unknown. Consequently, constructor theory must be deeper than all known physical theories such as quantum mechanics and relativity. He draws an analogy between this and conservation laws which are deeper than all other physical laws which must follow them. It's too early to say what impact Deutsch's new approach will have. But he has a spectacular record in physics having been a pioneer of quantum computation in the 1980s and one of the chief exponents of the multiverse, both of which have become mainstream ideas."

+ - The Major Theoretical Blunders That Held Back Progress in Modern Astronomy

Submitted by KentuckyFC
KentuckyFC (1144503) writes "The history of astronomy is littered with ideas that once seemed incontrovertibly right and yet later proved to be bizarrely wrong. Not least among these are the ancient ideas that the Earth is flat and at the centre of the universe. But there is no shortage of others from the modern era. Now one astronomer has compiled a list of examples of wrong-thinking that have significantly held back progress in astronomy. These include the idea put forward in 1909 that telescopes had reached optimal size and that little would be gained by making them any bigger. Then there was the NASA committee that concluded that an orbiting x-ray telescope would be of little value. This delayed the eventual launch of the first x-ray telescope by half a decade, which went on to discover the first black hole candidate among other things. And perhaps most spectacularly wrong was the idea that other solar systems must be like our own, with Jupiter-like planets orbiting at vast distances from their parent stars. This view probably delayed the discovery of the first exoplanet by 30 years. Indeed, when astronomers did find the first exo-Jupiter, the community failed to recognise it as a planet for six years. As Mark Twain once put it: "It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.”"

+ - How The Emerging Science of Proteotronics Will Change Electronics

Submitted by KentuckyFC
KentuckyFC (1144503) writes "The study of proteins has become one of the hottest topics in science in the last 20 years, and not just for biologists. Researchers have been measuring the electrical properties of proteins for some time, discovering that some of them act like switches in certain circumstances. That's potentially useful but without a robust theoretical model of how these properties arise, nobody has been able to incorporate proteins into real devices. Now electronics engineers have developed the first model that reliably describes the real electrical behaviour of proteins and how it changes when they bond to other molecules. It even predicts the behaviour in new situations. That should make it possible to use proteins in the same way as other electronic components such as transistors, diodes and so on. That's leading to an entirely new field of science called proteotronics in which proteins work seemlessly with other components in electronic devices. First up, an electronic nose based on the olfactory receptor OR-17, a protein found in rats, which behaves like an electronic switch when it detects the presence of aldehydes such as octanal."

Power corrupts. And atomic power corrupts atomically.