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Science & Technology News (891)

Finding How Memories are Made

Category: Science & Technology
Posted: May 1, 2015 02:48PM
Author: Guest_Jim_*

The brain is an extraordinary organ that humanity may never fully grasp, but that does not stop us from trying. One of the fundamental functions of the human brain is to store memories, and for some the brain has difficulty forming new memories, so a better understanding of the processes involved could lead to treatments for them. Now researchers at Vanderbilt University have found a link between a signaling protein and the formation of memories.

Neurons have two types of fibers that reach out from them, dendrites and axons, with the axons sending signals that dendrites receive. Each dendrite is covered in filaments called filopodia that will develop into spines when they touch an axon, and these connections are what store memories. The Vanderbilt researchers found that the signaling protein Asef2 promotes spine formation by activating another protein, and is used by another to guide specific spines. Previously Asef2 has been linked to disorders including autism, Alzheimer's, and Down Syndrome. Autism has been associated with immature spines, which fail to form good connections, and Alzheimer's is well known for disrupting a person's memory.

The hope is to one day understand the mechanisms well enough to develop treatments to restore spine formation. Until then, we have a lot more studying to do to unravel our brains at a cellular and molecular level.

Source: Vanderbilt University



New Technique Discovered for Creating Terahertz Radiation

Category: Science & Technology
Posted: May 1, 2015 06:15AM
Author: Guest_Jim_*

When X-ray photography was first discovered, it allowed us to peer into places previously impossible, and we may see a revolution like that happen again with terahertz radiation. Though at a much lower frequency, this form of light can be used to identify various illnesses and materials, at range and without damaging the subject. To best accomplish this though, a wide range of frequencies need to be created, and researchers at the University of Rochester have found a new way of doing so at a lower power than thought possible.

Specific frequencies of terahertz radiation can be made by special diodes and lasers, but these are only good for imaging work. Spectroscopy, which identifies materials by how light interacts with it, requires a broadband light source, which is made by a microplasma. To produce such a plasma requires either two powerful lasers of different frequencies, or one even more powerful laser. The Rochester researchers wondered if maybe working with special polarizations of light could improve efficiencies. It turns out this is not the case, but once the researchers learned why this did not work and the underlying physics, they found another solution. This new approach allows for the creation of the microplasma with a single laser at a much lower power than previously thought possible, and it may go even lower, by changing the gas used.

One thing interesting about this technique is that the terahertz waves go in a different direction than the laser beam, which should make it easier to couple the waves to a waveguide in a microchip.

Source: University of Rochester



Lithium-Ion Batteries Observed While Exploding in Real-Time

Category: Science & Technology
Posted: April 30, 2015 02:11PM
Author: Guest_Jim_*

Lithium-ion batteries are used in so many devices they practically surround us, and while most of the time this is not an issue, there are rare occasions when these batteries will explode. Obviously it is not good when a single battery explodes, but often one explosion can cause a chain reaction and neighboring batteries will explode as well. Researchers at University College London, Imperial College London, and the European Synchrotron Radiation Facility (ESRF) have now performed the first analysis of the internal structure of a battery as it explodes, in real-time.

The researchers studied two specific battery types, with one having an internal support and one not, and what occurs when thermal runaway happens. To do this they used one of the ESRF beamlines, which is capable of high speed 3D image capture. As the batteries were exposed to temperatures above 250 ºC, the researchers were able to watch the structures inside. The battery with the internal support apparently hit temperatures around 1000 ºC internally, because the copper support melted, and the heat spread out from there. In the other battery the tightly packed core collapsed, which would increase the risk of short circuits and damage to nearby objects.

While this study only worked with two types of battery, it demonstrates the feasibility of this analysis method for other types. Now the researchers are going to study a larger sample of batteries and examine the microscopic changes involved with failure.

 

 

Source: University College London



New Trillion FPS Camera Developed

Category: Science & Technology
Posted: April 30, 2015 05:22AM
Author: Guest_Jim_*

For most people, it may be hard to imagine something happening in a trillionth of a second, but for some researchers, that is how fast the processes they are trying to study occur. As you can guess, that tremendous speed makes studying these processes difficult, which is why one group of researchers have created a new camera to capture what happens. As reported by The Optical Society, researchers from Japan have succeeded in creating a camera capable of capturing 4.4 trillion frames per second.

Normally if someone wants to study some ultrafast processes, they have to utilize the pump-probe method to record what is happening. While this method can achieve astounding framerates, it can only capture a frame at a time. To create movies using the method requires repeating the process multiple times, which is not always viable. The new camera, called STAMP (Sequentially Timed All-optical Mapping Photography) however can capture multiple frames and at a resolution of 450x450 pixels. It works by splitting an ultrashort pulse of light into colored flashes, like sunlight dispersing into a rainbow. These flashes then strike the target at different times and can be analyzed to create a motion picture. As electrical and mechanical cannot keep up with the necessary processing speed, STAMP uses optical components exclusively.

The applications for STAMP are numerous, including studying nuclear fusion and lattice vibrations, and it is almost certain many have not yet been imagined. Currently the researchers are working on an improved STAMP system that will be capable of catching 25 sequential images, while the original was only able to capture 6. Eventually this could be pushed up to 100 frames.

Source: The Optical Society



Taking Better 3D Images Faster with a New Camera

Category: Science & Technology
Posted: April 29, 2015 02:26PM
Author: Guest_Jim_*

I think it is safe to say that the people behind the Kinect at Microsoft probably did not anticipate the myriad of ways people would use it. Beyond gaming the sensor has applications for robotics, cars, medicine, and much more, but it also has several limitations. Researchers at Northwestern University decided to see if they could overcome those limitations, and have with a new 3D scanning system.

Both versions of the Kinect rely on projecting a pattern of light onto the environment, and capturing how it lands on objects with a camera. While this works quickly, it is not very precise compared to other methods, so the images produced are of low quality. Single-point scanners that scan a laser across an area are more precise but can be slower. To get around that the Northwestern researchers incorporated how our eyes work, which is to only update the parts of an image when they change.

Another limitation of the Kinect sensor is that it cannot work outside, because Sunlight can overcome the sensor. This new sensor however uses a laser brighter than ambient light, so it can work in any environment.

 

 

Source: Northwestern University



Reducing Noise in Aircraft with New Membrane

Category: Science & Technology
Posted: April 29, 2015 06:04AM
Author: Guest_Jim_*

The engines of planes and helicopters can be very loud, but there is little that can be done about it. Modern aircraft bodies use a honeycomb-like structure to stay light, but they do little to block noise and adding insulation would add too much weight to be viable. Researchers at North Carolina State University and MIT may have a solution though, in the form of a membrane.

The membrane is made of rubber and stretched over the honeycomb structure, similar to the skin on a drum. When sound hits it, the waves reflect off instead of passing through, reducing the sound energy by a factor of 100 to 1000 for low frequencies, like those from aircraft engines. At just 0.25 millimeters thick the membrane also only adds about 6% to the weight of a honeycomb panel, keeping things pretty light. On top of that, the membrane can be cheaply produced from a number of materials, so it will not interfere with the panel's structural integrity.

Source: North Carolina State University



Could the Universe be a Hologram?

Category: Science & Technology
Posted: April 28, 2015 02:28PM
Author: Guest_Jim_*

Holography is an interesting field of science with how it can create three-dimensional views with two-dimensional systems. This is something you can see in credit cards and even some banknotes, and back in 1997 it was suggested that the principles of holography could be applied to the Universe itself. Now researchers at the Vienna University of Technology have discovered an unexpected level of correspondence between two theories that apply to the Universe.

Holograms create images with so many dimensions by combining two systems of lower dimension. If applied to the Universe that would mean it can be described mathematically with one fewer dimension than we think. We already know that the holographic principle can be applied to some spaces by a correspondence between gravitational theories, which have three dimensions, and quantum field theories, which were calculated in just two dimensions, but those spaces would have to be curved in a negative direction, while the Universe has flat curvature, or positive over great distances. The Vienna researchers however have found that the correspondence actually does still exist in a flat space. To do this they had to find properties of one theory in the other, such as quantum entanglement in gravitational theory.

While this work does indicate that the correspondence principle does likely apply to our Universe, it does not immediately mean the Universe is actually a hologram.

Source: Vienna University of Technology



Liquid Nanolaser with Tunable Wavelength Developed

Category: Science & Technology
Posted: April 28, 2015 06:13AM
Author: Guest_Jim_*

Since their creation, lasers have proven an invaluable tool for analysis, and that is not going to change anytime soon. With a push towards developing lab-on-a-chip technologies, lasers may become even more useful, in their smallest forms. Researchers at Northwestern University have recently created a nanolaser that is partially liquid and tunable, which would be of great use in various technologies, including lab-on-a-chip devices.

Instead of using a lasing material between two mirrors to stimulate and amplify light of a specific frequency, this new lasers uses gold nanoparticles in a solution. Thanks to plasmonics, the gold nanoparticles concentrate the light around themselves, amplifying it. Plasmonic lasers have been made before, but always with a solid gain material, so this is the first liquid nanolaser. Among the advantages to using a liquid is that the liquid can be manipulated to alter the laser, such as changing the index of refraction to tune the frequency of the laser. This tuning can even be done in real time.

While lab-on-a-chip devices may be one of the best examples of an application for this technology, it could also be used in optical data storage and lithography. All of these applications would likely benefit from how relatively inexpensive the design is and its stability, as the gain molecules can be constantly replaced.

Source: Northwestern University



Special Cloud Security System Built Into Chips

Category: Science & Technology
Posted: April 27, 2015 05:26AM
Author: Guest_Jim_*

Securing our data can be very important, especially if that data is something sensitive like credit or medical information. This can be tricky to accomplish though, as many systems are moving to the Cloud, where a user's data may be on the same server as an attacker. Two years ago researchers at MIT designed a way to thwart some of these attacks, and now they have successfully built it into chips, which would make actually deploying it much simpler.

Many people may think that so long as data cannot be read, it is protected, but actually attackers can learn a great deal without ever seeing the data. Instead they can look to what a system does with it, such as how it calls the memory. To secure against such attacks, the MIT researchers developed a technique that calls multiple memory addresses at a time, obfuscating what the desired address was from the attacker. This was accomplished by treating all of the addresses as nodes in a tree, with one node immediately above, and several nodes below. When calling one address, the entire path of nodes from it to the top of the tree is called, and so the entire path is written to as well.

By building this method into hardware, it can be run much more efficiently, but to achieve this, the researchers had to develop some interesting tricks. For example, writing to a path on the tree is difficult to do on hardware, because it would normally require sorting. By adding an extra memory circuit though, the information can be stored there and then written to the main memory once its location has been determined. This writing is also done on only ever fifth read, to further improve efficiency.

Source: MIT



MRI Records Vocal Movements at 100 FPS

Category: Science & Technology
Posted: April 24, 2015 02:38PM
Author: Guest_Jim_*

Our voices and how we speak are part of how we stand apart from each other, but as we age, these can change. Over time the muscles and tissues involved degrade, leading to weaker or strained voices, but some researchers at the Beckman Institute are interested in finding ways to prevent or reverse this. To that end the researchers have used an advanced MRI technique that allows for detailed images to be captured at an unprecedented speed of 100 frames per second.

There are over one hundred muscles involved with speech, spanning from our chest and neck to our jaw, tongue, and lips. To understand how they all work together and how they change over time, the researchers needed a view inside the human body, while the subject was speaking. Actually the subject was singing 'If I Only Had a Brain.' Obviously the person does, as you can see it in the MRI, and much more. The MRI technique was also developed at the Beckman Institute, and at 100 FPS is significantly faster than any other technique. Typical MRIs operate at around 10 FPS.

 

 

Source: Beckman Institute for Advanced Science and Technology



New Potential Discovered for Double-Walled Nanotubes

Category: Science & Technology
Posted: April 24, 2015 05:59AM
Author: Guest_Jim_*

Nanotubes are among the carbon allotropes that have piqued the interest of many since their discovery, thanks to their special properties. One of the hopes for these materials is that they can be used to create advanced electronic devices. Now researchers at Rice University have found that some important properties can be tuned for double-walled nanotubes.

Carbon nanotubes are long cylinders of carbon atoms, arranged in hexagons, and come in various forms, include single and multi-walled. Single-walled nanotubes are made of a single cylinder, whereas multi-walled nanotubes are comprised of multiple concentric tubes, and are stronger and stiffer than the single-walled versions. It turns out that double-walled nanotubes exist in a nice place as they have some of the useful properties of single-walled nanotubes, while still being stronger and stiffer. Now the Rice researchers have determined, with atomic-level models, that the properties of double-walled nanotubes can be tuned by manipulating specific properties. For example, the band gap can be controlled by altering the separation between the inner and outer tubes, if the inner tube is semiconducting and outer tube is metallic.

At the moment there is sadly no way to control the growth of double-walled nanotubes with the necessary accuracy, but this research still indicates a great future for such efforts. Also other configurations of nanotubes could have other properties beneficial for various applications.

Source: Rice University



3D Printed Graphene Aerogel May Improve Various Technologies

Category: Science & Technology
Posted: April 23, 2015 02:28PM
Author: Guest_Jim_*

Aerogels are a fun class of materials as they are unbelievably light and have some unique uses, such as collecting dust from a comet's tail. By making them out of different materials, one can get special properties, but some materials are harder to work with than others. Researchers at Lawrence Livermore National Laboratory have recently managed to create an aerogel out of graphene by 3D printing, which is something many have tried and failed to do before.

Aerogels sometimes referred to as 'liquid smoke' and are made by replacing the liquid component of a gel with a gas. Attempts at making one from graphene have more or less failed because the pore structure has been so random, making it impossible to control its mass transport and mechanical properties. The LLNL researchers solved this problem though by turning to a kind of 3D printing called direct ink writing. The ink in this case was an aqueous solution of graphene oxide, mixed with silica, and it was extruded from a micronozzle to form the 3D structure. This allows for the necessary control over pore structure and physical properties.

The resulting aerogel is electrically conductive, lightweight, has a high surface area, and demonstrates supercompressibility. The material could end up finding uses in energy storage, sensors, nanoelectronics, catalysis and separations, and more thanks to the ability to print almost any complex structure desired.

 

 

Source: Lawrence Livermore National Laboratory



Forums Can be Good for Well-Being and More

Category: Science & Technology
Posted: April 23, 2015 06:50AM
Author: Guest_Jim_*

It has been interesting to see how the Internet has changed over the past decade, with social media effectively replacing forums as a means of interacting with others. Despite that change though, forums are still regularly used by many, and are impacting people's lives. That impact may be more than you expect though, as researchers at the University of Exeter have found forum use can significantly improve a user's well-being.

For their study, the researchers surveyed users of forums with stigmatized and non-stigma-related topics, such as mental health issues for the former, and golf for the latter. The survey asked about why people joined the forum, how their expectations were fulfilled, how they identified with other users, their satisfaction with life, and their offline engagement with forum issues. What the researchers found is that those who sought out forums for answers also found them to be sources of support, especially for stigmatizing issues. As the users engaged more, regardless of the nature of the topic, they became more willing to get involved in related offline activities.

As the researchers sum up, by putting more into a forum, the users can get more back. As this also results in more offline engagement and activities, such as volunteering and donating, society can come to be significantly impacted as well.

Source: University of Exeter



Tabletop Particle Detector May Measure the Energy of an Electron

Category: Science & Technology
Posted: April 22, 2015 02:28PM
Author: Guest_Jim_*

Right now billions of neutrinos are streaming through your body, without interacting with any of your cells. Neutrinos are weird particles like that, as they do not interact with much of anything, so we have little knowledge of them. Researchers at MIT, however, may be bringing us closer to determining their mass with a new particle detector.

Many processes emit neutrinos, including the decay of tritium into an isotope of helium. When this happens, a neutrons turns into a proton and emits an electron and a neutron. As the sum of the output must add up to the input, researchers want to narrow down the energy of a single electron to determine the mass of a single neutrino. To that end the MIT researchers have built a particle detector that can pick up the emissions of a single electron. It works by trapping the electron in a magnetic bottle, and then, when the electron moves through a magnetic field, it emits radio waves, which can be used to analyze the electron.

This new detector is small enough to fit on a table top and the area the electrons are tracked in is smaller than a stamp. This in comparison to an advanced spectrometer being used elsewhere that barely fit in city streets. Currently the detector has only worked with krypton, but in a couple years it should be able to move up to tritium.

Source: MIT



Graphene Converts Light to Electricity at Amazing Speeds

Category: Science & Technology
Posted: April 22, 2015 06:02AM
Author: Guest_Jim_*

One day we may be able to say graphene has no secrets left, but that time has not come yet. One of the material's potential uses is for converting light to electrical signals, which could find it applications in cameras, sensors, solar cells, and data communication. Now researchers at the Institute of Photonic Sciences (ICFO) have determined just how fast this conversion process is; under 50 femtoseconds.

Graphene is an atom-thick sheet of carbon atoms that has some special electrical properties, including very fast and efficient interactions between electrons. These interactions naturally come into play with this high conversion speed. When a pulse of light strikes graphene, the researchers found, it causes the electrons to disperse and their temperatures to rise very quickly. This electron heat is converted into a voltage when it comes to the interface between graphene regions with different doping. Thus the effect is actually photo-thermoelectric and occurs almost instantly.

This research could obviously lead to ultra-fast optoelectronic conversion systems, which could be put to use for data transmission, amongst other applications.

Source: The Institute of Photonic Sciences



Increasing Public Wireless Bandwidth with WiFO

Category: Science & Technology
Posted: April 21, 2015 02:25PM
Author: Guest_Jim_*

As people rely on their mobile devices more and more, we also come to depend on wireless networks. In our homes and on our private networks, bandwidth may not be a problem, but in public places where large numbers of devices may try to connect to the same network, speeds can drop significantly. To help speed things back up, researchers at Oregon State University have developed WiFO, which leverages LEDs for faster transmissions.

Current Wi-Fi networks use radio waves that work well for covering large areas, but have some speed limitations. By shifting to higher frequencies of light, transmission rates can be increased, so many researchers have been working on ways to use LEDs for sending information. The Oregon researchers are using recent advances that allow for faster modulation of LEDs, which is necessary for high speed transmissions, in their WiFO system. The system is more than just LED transmitters though as it is a hybrid system that works across multiple ceiling-mounted LEDs and existing Wi-Fi systems.

Potentially the WiFO LEDs could transmit at 100 Mbps, and as numerous LEDs would be used across an area, each covering about a square meter, users could see 50 – 100 Mbps. Of course devise will need a compatible receiver, which are small photodiodes that cost less than a dollar and could use USB ports on old devices, or integrated into future ones.

Source: Oregon State University



Lithium Ions Replaced with Magnesium

Category: Science & Technology
Posted: April 21, 2015 06:13AM
Author: Guest_Jim_*

Battery technology is important all over the world, so a great many are working on ways to advance the field. One of the ways of doing this is to change the chemistry involved and move away from lithium ions, to something more potent. This is what researchers at the University of Illinois at Chicago have been working towards, by replacing lithium with magnesium.

Lithium ions possess a single positive charge, which translates to a single electron that a battery can release or store. Magnesium ions though have two positive charges, so a magnesium-ion battery would have double the energy density and power. Actually creating a magnesium-ion battery is not easy, but the Illinois researchers have made an important step by successfully swapping them in for lithium in part of a battery. It is important to show that magnesium ions can move in and out of the electrodes of a battery like lithium ions already do, before a battery can be realized, and that is what the researchers have achieved.

What the researchers have built is still only part of a battery, but it demonstrates the reaction we would find in a battery. Obviously more work needs to be done to reach that goal, but you can believe many are going to take this research and run with it.

Source: University of Illinois at Chicago



Self-Powered Camera Created

Category: Science & Technology
Posted: April 20, 2015 02:03PM
Author: Guest_Jim_*

Something you may not realize when looking at them is that solar panels and digital cameras operate in very similar ways. Both technologies rely on photodiodes to convert light to an electrical current, but while one uses the current for power, the other measures it for optical information. Researchers at Columbia University decided to combine these two purposes and built a camera that is actually able to power itself.

The camera is housed in a 3D printed body, consists of 40 x 30 pixels, and each pixel is made up of just two transistors. When in operation, the pixels switch between image capture and energy harvesting modes, charging capacitors to provide the necessary power. The researchers could have used a rechargeable battery instead, but opted for capacitors to better demonstrate the self-powered design. If the camera is not set up to record images, it can be used to power other devices.

The hope for this first fully self-powered video camera is to lead to camera capable of running for very long durations, or even forever, as it is not reliant on an external power source. It could also be developed into a compact solid-state imaging chip.

 

 

Source: Columbia University



Miniature Track Pad Developed for Easy Access

Category: Science & Technology
Posted: April 20, 2015 06:04AM
Author: Guest_Jim_*

From track pads to touchscreens, touch-based interfaces are around us every day, somehow improving how we connect and use a device. Sometimes our hands are filled though, or cannot reach for our phones or laptops, so some other solution is needed. Researchers at MIT may have come up with just such a solution by building a trackpad the size of a thumbnail.

Named NailO, the device consists of a capacitive sensor and corresponding chip, microcontroller, Bluetooth radio, and small battery. At first the sensor was made of copper electrodes printed onto flexible polyester sheets, but later these were replaced with off-the-shelf sheets already used in some trackpads. All of these were designed to fit on our thumbnail, where a user can comfortable reach and use it. As the thumbnail is hard and lacks nerve endings, it can be affixed and used without causing any discomfort.

Obviously the technology has applications for subtly controlling devices, but it will likely find other uses as well. It really depends on how we decide to interact with devices in the future.

 

 

Source: MIT



Games Offer More Than Just Fun for the Player

Category: Science & Technology
Posted: April 17, 2015 04:38PM
Author: Guest_Jim_*

It is certainly true that there are some games in my library that I play just for fun, but there are also some, I would say go farther. Apparently this is not unique to me as researchers at Penn State have come to the same conclusion in a recent study.

The study took 512 gamers and split them into two groups. Both groups were asked to rate their perceptions about a game they played, but as one group had a particularly fun game, the other had a more meaningful game. The two groups agreed the games were fun to play, but those playing the more meaningful game appreciated the experience more.

This finding is probably not that surprising, but may still be important, to show that video games do have a place with other media forms, for giving the consumer a meaningful entertainment experience that is deeply appreciated. Given the interactive nature of video games, the experience could be even stronger, compared to books or movies. While there is nothing wrong with just silly, fun games, this shows that it can be worth it for developers to create the emotional stories and narratives of some games.

Source: Penn State



Temperature Observed in Quantum System

Category: Science & Technology
Posted: April 17, 2015 06:49AM
Author: Guest_Jim_*

Never expect anything to be simple in quantum mechanics, but then somethings in classical mechanics can be very complicated as well. Temperature is one such example as that simple value describes absurdly complex and chaotic activity. Researchers at the Vienna University of Technology have at long last succeeded in studying how gases behave with temperature, when their quantum properties are brought out.

The molecules in the air around us are zipping around and bouncing off of each other and other objects so much that it would be impossible to track them all, but luckily scientists do not have to, in order to describe them. Instead they rely on statistical physics to determine the properties of the entire gas, but this has led to the question of how one gets from statistical mechanics to quantum mechanics. To answer that, the Vienna researchers used a microchip to catch and cool several thousand atoms to a little above absolute zero, to bring out their quantum properties. By manipulating the chip, the quantum gas could be manipulated as well, and the researchers found the gas could take on multiple temperatures at the same time. Though predicted, this behavior has never been observed before.

For now this research should lead to an improved understanding of quantum mechanics and its relationship to thermodynamics. Someday it may lead to new technological applications as well as how our classical laws of physics emerge from those of quantum mechanics.

Source: EurekAlert!



Probabilistic Programming Brought to Computer Vision

Category: Science & Technology
Posted: April 16, 2015 02:14PM
Author: Guest_Jim_*

One of the many uses of machine learning is computer vision, whereby a computer analyzes a scene and identifies the objects in it, without them exactly matching known models. Building these algorithms can requires thousands of lines of code, but some are turning to probabilistic programming languages to simplify the work. In the case of the Picture language MIT researchers developed, those thousands of lines can be simplified to less than 50.

Probabilistic programming differs from deterministic programming by being based more on inference, which fits well with machine learning. Instead of requiring very specific descriptions, programmers can describe a vague model that the program runs through inference schemes to solve, using inverse-graphics reasoning. The MIT researchers have tested Picture by giving it the simple description of the human face as having two symmetrically placed eyes, with the nose and mouth positioned beneath them. Armed just with that knowledge and examples, the program was tasked with working through 2D images to construct 3D models, and was able to match the thousand-line programs, and in some cases surpass them.

Technically more code than 50 lines is involved behind Picture, as it draws on multiple inference algorithms, but the model for the task itself is still much simpler. This is actually one of the purposes of probabilistic programming languages, where the language is generic and can be used with many inference algorithms, depending on the task.

Source: MIT



First All-Photonic Quantum Repeaters Designed

Category: Science & Technology
Posted: April 16, 2015 05:53AM
Author: Guest_Jim_*

One day we may see the construction of a quantum Internet that will be far more secure than today's global network. This is thanks to quantum encryption, which protects data from being read and alerts users to eavesdroppers. For it to work though, we need the ability to transmit photons in a quantum state over great distances, and researchers at the University of Toronto have designed a technology to help with that.

Even modern optical communications require repeaters to ensure classical signals survive their travels, so more fragile quantum signals need special repeaters to preserve the information. The current technology for doing so is complicated, acting like a mini quantum computers, requires low temperatures, and is kind of slow. What the Toronto researchers have created is an all-photonic quantum repeater that comes with several benefits. Just by being all photonic the system is much simpler, as it no longer requires a physical quantum memory system, or an interface between matter and light. It is also able to operate at room temperatures, has a higher communication rate, and a superior fault-tolerance.

One aspect to this design that is particularly interesting is that its components have already had proof-of-principle demonstrations made. This work started as an attempt to transmit polarization over long distances, but then the researchers decided to try for the 'fancier' quantum teleportation, which teleports the entire state of a particle from one location to another.

Source: University of Toronto



Invisibility Achieved Without Metamaterials

Category: Science & Technology
Posted: April 15, 2015 02:26PM
Author: Guest_Jim_*

People have been fascinated with the idea of invisibility for millennia, but only in modern times may we actually achieve it. Metamaterials are man-made materials with properties impossible to find in Nature and can be used to cloak objects. As it turns out though, there is a simpler way of achieving invisibility, and researchers at ITMO University, Ioffe Institute and Australian National University have done just that.

What the researchers have done is take advantage of a classical problem concerning the scattering of light from a homogeneous sphere that was solved almost a century ago. When light strikes an object of high refractive index it can scatter by two mechanisms: resonant and non-resonant scattering. Instead of a sphere, the researchers were working with a glass cylinder filled with water, which they change the refractive index of by changing the water's temperature. By doing this correctly, the resonant and non-resonant mechanisms scattered waves of opposite phases, causing them to cancel each other out, making the object invisible. This was achieved for microwaves at 1.9 GHz and by changing the temperature of the water from 90 ºC to 50 ºC.

Though the current work dealt with microwaves, it could be applied to the visible spectrum of light. It could also have applications for the development of nanoantennas, such as building invisible support structures. As these structures would not need special, metamaterial coatings, they would be much simpler to make.

Source: ITMO University



New Observations Reveal More Secrets of Dark Matter

Category: Science & Technology
Posted: April 15, 2015 05:56AM
Author: Guest_Jim_*

Humans have been looking to the sky for probably as long as we have had eyes, and there are still many mysteries to solve. Among these is dark matter, a source of gravitational force that may have a link to galaxy formation and the continued existence of galaxies as well. Now researchers at the European Southern Observatory have found dark matter interacting with itself in an unpredicted way.

Nobody knows what dark matter is, but we do know we cannot see it. That is not the reason we refer to it as being 'dark' though, or at least it is not the only reason. It is also called dark because it does not interact directly with normal, light matter, which also interacts with light. It even seems that dark matter does not interact with itself, except through gravity. The only means we have to observe dark matter is by the bending of light its gravity causes as light travels through the Universe. The ESO researchers looked to a collision of four galaxies and mapped the distribution of dark matter in the collision, finding one clump of it lagging behind the galaxy it surrounds. The amount of lag cannot be described by gravity though, which means there must be some other force involved. Whether that force is something we already know or something completely exotic can only be determined with more research.

This research nicely pairs with that of another team looking at collisions of galaxy clusters, which also indicated that dark matter interacts with itself. Together these studies put brackets on the behavior of dark matter, and eventually we may be able to squeeze down to whatever dark matter really is.

Source: ESO



Manipulating Magnetism for Spin-Orbitronics

Category: Science & Technology
Posted: April 14, 2015 02:03PM
Author: Guest_Jim_*

Currently our computers rely on the charge of electrons to operate, but in the future computers may use electron spin instead, as it offers many benefits. Often these two properties seem to be kept separate, but by combining coupling these properties we can develop spin-orbitronics. Devices based on this field can be smaller, faster, and more energy efficient and researchers at Berkeley Lab have made a discovery to bring them closer to reality.

Central to many of our computers and the Internet is magnetic data storage, which relies on magnetic domains in magnetic films. What the Berkeley researchers have found concerns the walls between these domains and how they react to electrical currents. Within magnetic domains all of the spins of electrons are aligned either up or down, but the walls between them can be much more interesting. These walls can have spins that rotate in a helical spiral or in a cycloidal spiral, and either can have right or left-handed chirality. When a current runs through them the walls, depending on their spin, can be propelled with the current, against the current, or to the left or right. The researchers also found that the handedness of the walls can be flipped by controlling the strain on the film.

Spin-orbitronics could open up new ways to store data in magnetic memory devices. This would include storage devices that rely on electrical currents, instead of mechanical systems to retrieve data.

Source: Berkeley Lab



Qubits Controlled with Electric Fields for First Time

Category: Science & Technology
Posted: April 14, 2015 05:30AM
Author: Guest_Jim_*

It is hard to say exactly when, but eventually we are going to have quantum computers capable of quickly performing operations even the best modern computers cannot. Much needs to be done before then though, both in terms of developing new technologies, and refining them to be easily produced. Researchers at the University of New South Wales have recently achieved both by successfully altering a qubit inside a silicon chip with an electric field.

Qubits, or quantum bits, are what quantum computers rely on, and unlike electronic bits that stores zeroes or ones, qubits are capable of representing both zero and one at the same time. This is thanks to the quantum mechanics phenomenon known as superposition. Manipulating qubits is somewhat challenging, in part because of how fragile they are, but the New South Wales researchers were able to control one using electric fields. The qubit was actually a phosphorus atom within silicon-28, an isotope of silicon that is completely non-magnetic and does not disturb the qubit. Normally manipulating such a qubit requires pulses of oscillating magnetic fields.

By achieving control over single qubits with just electric fields, a quantum computer could be made much more cheaply, by using voltage generators instead of high-frequency microwave sources. Also the manufacturing process needed to produce the qubit is similar to that used to create computer chips, further reducing costs.

Source: EurekAlert!



Keeping Electrons Cool to Make Efficient Electronics

Category: Science & Technology
Posted: April 13, 2015 02:27PM
Author: Guest_Jim_*

Efficiency has always been a priority when it comes to designing electronics, and with today's nanotechnologies, the ways to achieve it are more becoming much more advanced. Researchers at the University of Texas at Arlington have been awarded a $300,000 grant from the NSF to work on a new transistor design that could improve efficiency by a factor of ten.

This new transistor design is quite different from traditional designs as all of the components are contained in a single nanopillar, less than 50 nm in diameter, and arranged vertically, so they can still be packed in on a chip. Besides its geometry, the transistors are also special because the electrons can flow through them without heating up. This is achieved by passing the electrons through a quantum well, which will cool them down to -228 ºC at room temperature, and without special external means. By keeping the electrons cool, the transistors can operate with less energy, and of course generate less heat. The results would be longer battery lives and/or lighter loads to carry.

Source: University of Texas at Arlington



Cosmological Mile Markers Less Standard than Thought

Category: Science & Technology
Posted: April 13, 2015 06:23AM
Author: Guest_Jim_*

For any scientific endeavor, you must have accurate measurements because without them a slew of calculations can be thrown off or produce incorrect results. A research team, led by researchers at the University of Arizona, has discovered that certain cosmological measurements are inaccurate, and that our understanding of dark energy may be off.

For a long time it was believed that the size of the Universe was constant, and then it was determined to be expanding, but today we know the expansion is actually accelerating. The exact cause of this acceleration is not known, but has been given the name dark energy. It was discovered by measuring the light emitted by type Ia supernovas, which are explosions of white dwarf stars, throughout the history of the Universe, and comparing their brightness. It has long been believed that this type of supernova is constant and thus always produces the same light, thereby allowing them to act as cosmic candles. What the researchers discovered is that these supernovae are not as constant as believed, as one looks back in time. Instead the researchers found that two distinct populations exist, with those nearer to us being more red than those farther away, from when the Universe was younger.

This discovery was only made possible thanks to the ultraviolet capabilities of the NASA Swift satellite, as the differences in visible light are much more subtle. The researchers found this different both in their own datasets and in others. The exact implications this discovery may have on our understanding of dark energy and astronomy are not yet known and will require a great deal more data to determine.

Source: University of Arizona



Phonon Tunneling Explains Heat Transfer Across Small Gaps

Category: Science & Technology
Posted: April 10, 2015 02:24PM
Author: Guest_Jim_*

Whether it is hot or cold, heat transfer is important to us and in most cases it is well understood. For situations are covered by convection, conduction, or radiation, but at the small scale of a nanometer or less, things get harder to explain. That has changed now, thanks to researchers at MIT who have found that quantum tunneling can explain how heat can jump the gap.

When discussing heat at small scales, phonons must be part of the conversation as they are the energy units for vibrational energy and heat. Exactly explaining how phonons move has been a challenge for a long time now, as some theories skip over what happens at the atomic scale and others have obvious flaws to them. To find the solution, the MIT researchers turned to the microscopic Maxwell's equations, which are a form of the better known Maxwell's equations that govern electricity and magnetism. When these were applied the researchers found that phonons could actually tunnel across gaps between objects separated by just one nanometer or less. Tunneling is a quantum mechanical phenomenon where a particle or wave will skip over, or tunnel through a barrier it normally should not be able to.

With this answer, we have a more complete understanding of how heat flows, as now that understanding finally reaches to the nanoscale. It of course has practical applications wherever heat transfers, especially at very small scales.

Source: MIT



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