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Three computer scientists have announced the largest-ever mathematics proof: a file that comes in at a whopping 200 terabytes1, roughly equivalent to all the digitized text held by the US Library of Congress. The researchers have created a 68-gigabyte compressed version of their solution — which would allow anyone with about 30,000 hours of spare processor time to download, reconstruct and verify it — but a human could never hope to read through it.
Computer-assisted proofs too large to be directly verifiable by humans have become commonplace, and mathematicians are familiar with computers that solve problems in combinatorics — the study of finite discrete structures — by checking through umpteen individual cases. Still, “200 terabytes is unbelievable”, says Ronald Graham, a mathematician at the University of California, San Diego. The previous record-holder is thought to be a 13-gigabyte proof2, published in 2014.
The puzzle that required the 200-terabyte proof, called the Boolean Pythagorean triples problem, has eluded mathematicians for decades. In the 1980s, Graham offered a prize of US$100 for anyone who could solve it. (He duly presented the cheque to one of the three computer scientists, Marijn Heule of the University of Texas at Austin, earlier this month.) The problem asks whether it is possible to colour each positive integer either red or blue, so that no trio of integers a, b and c that satisfy Pythagoras’ famous equation a2 + b2 = c2 are all the same colour. For example, for the Pythagorean triple 3, 4 and 5, if 3 and 5 were coloured blue, 4 would have to be red.
In a paper posted on the arXiv server on 3 May, Heule, Oliver Kullmann of Swansea University, UK, and Victor Marek of the University of Kentucky in Lexington have now shown that there are many allowable ways to colour the integers up to 7,824 — but when you reach 7,825, it is impossible for every Pythagorean triple to be multicoloured1. There are more than 102,300 ways to colour the integers up to 7,825, but the researchers took advantage of symmetries and several techniques from number theory to reduce the total number of possibilities that the computer had to check to just under 1 trillion. It took the team about 2 days running 800 processors in parallel on the University of Texas’s Stampede supercomputer to zip through all the possibilities. The researchers then verified the proof using another computer program.
A team of physicists at the University of California has uploaded a paper to the arXiv preprint server in which they suggest that work done by a team in Hungary last year might have revealed the existence of a fifth force of nature. Their paper has, quite naturally, caused quite a stir in the physics community as several groups have set a goal of reproducing the experiments conducted by the team at the Hungarian Academy of Science's Institute for Nuclear Research.
The work done by the Hungarian team, led by Attila Krasznahorkay, examined the possible existence of dark photons—the analog of conventional photons but that work with dark matter. They shot protons at lithium-7 samples creating beryllium-8 nuclei, which, as it decayed, emitted pairs of electrons and positrons. Surprisingly, as they monitored the emitted pairs, instead of a consistent drop-off, there was a slight bump, which the researchers attributed to the creation of an unknown particle with a mass of approximately 17 MeV. The team uploaded their results to the arXiv server, and their paper was later published by Physical Review Letters. It attracted very little attention until the team at UoC uploaded their own paper suggesting that the new particle found by the Hungarian team was not a dark photon, but was instead possibly a protophobic X boson, which they further suggested might carry a super-short force which acts over just the width of an atomic nucleus—which would mean that it is a force that is not one of the four described as the fundamental forces that underlie modern physics.
The paper uploaded by the UoC team has created some excitement, as well as public exclamations of doubt—reports of the possibility of a fifth force of nature have been heard before, but none have panned out. But still, the idea is intriguing enough that several teams have announced plans to repeat the experiments conducted by the Hungarian team, and all eyes will be on the DarkLight experiments at the Jefferson Laboratory, where a team is also looking for evidence of dark photons—they will be shooting electrons at gas targets looking for anything with masses between 10 and 100 MeV, and now more specifically for those in the 17 MeV region. What they find, or don't, could prove whether an elusive fifth force of nature actually exists, within a year's time.
More information: arxiv.org/pdf/1604.07411v1.pdf A. J. Krasznahorkay et al. Observation of Anomalous Internal Pair Creation in: A Possible Indication of a Light, Neutral Boson, Physical Review Letters (2016).
A pair of researchers with Leibniz University of Hannover has demonstrated the means by which robots might be programmed to experience something akin to pain in animals. As part of their demonstration at last week's IEEE International Conference on Robotics and Automation held in Stockholm, Johannes Kuehn and Sami Haddaddin showed how pain might be used in robots, by interacting with a BioTac fingertip sensor on the end of a Kuka robotic arm that had been programmed to react differently to differing amounts of "pain."
The researchers explained that the reason for giving robots pain sensors is the same as for existing biological adaptations—to ensure a reaction that will lessen the damage incurred by our bodies, and perhaps, even more importantly, to help us to remember to avoid similar situations in the future. In the case of the robots, the researchers have built an electric network behind the fingertip sensor meant to mimic nerve pathways below the skin in animals, allowing the robot to "feel" what has been programmed to describe various types, or degrees of pain.
In the demonstration, the researchers inflicted varying degrees of pain on the robot, explaining the reasoning behind the programmed reaction: When experiencing light pain or discomfort, for example, the robot recoiled slowly, removing itself from the problem. Moderate pain, on the other hand called for a rapid response, moving quickly away from the source, though it had the option to move back, albeit, tentatively, if need be. Severe pain, on the other hand, is often indicative of damage, thus the robot had been programmed to become passive to prevent further damage.
Such robots are likely to incite a host of questions, of course, if they become more common—if a robot acts the same way a human does when touching a hot plate, are we to believe it is truly experiencing pain? And if so, will lawmakers find the need to enact laws to prevent cruelty to robots, as is the case with animals? Only time will tell of course, but one thing that is evident in such demonstrations—as robotics technology advances, researchers are more often forced to make hard decisions, some of which may fall entirely outside the domain of engineers.
Monsters, moonshine and shadows sound like the ingredients for an excellent fairy tale. They are also part of a fascinating mathematical story that brings together some of our favorite things – number theory, group theory, string theory and even quantum gravity – as well as some of our favorite mathematicians.
The monster in question comes from group theory – the mathematical study of symmetry. A group is a set of things (usually called elements) and a rule for how these elements interact so the resulting system is self contained and satisfies some simple rules. You can read all the details in The power of groups.
One of the original inspirations for group theory came from studying symmetry groups – the symmetries that can exists together in an object. For example the symmetries of a rectangle are reflection in the vertical axis, reflection in the horizontal axis and a half-turn around the centre. These symmetries of a rectangle, together with the identity symmetry (that does nothing), form the Klein 4-group – one of the smallest groups.
There are also infinite groups, such as the set of whole numbers which form a group under addition. But every group, finite or infinite, is made up of building blocks called simple groups in an analogous way to every number being uniquely expressible as a product of prime factors.
One of the greatest mathematical achievements of the last century was the classification of the finite simple groups, an enormous theorem that took over 30 years, 100 mathematicians and 10,000 pages to prove. This result gave a description of every type of finite simple group: they were either one of 18 well-understood infinite families (such as addition modulo a prime number, eg. addition modulo 7) or they were one of 26 other individual possibilities (called the sporadic groups). The largest of these 26 outsiders is the Monster group, which consists of a mind-boggling
It turns out that every group, whether it's the symmetries of a rectangle or the whole numbers under addition, can be represented using mathematical objects called matrices. These are extensions of one-dimensional linear functions, such as , to higher dimensions. Each element of the group corresponds to a matrix that acts in -dimensional space, and these matrices behave in the same way that the original group elements (that is if for elements , and in the group, then for the corresponding matrices , and in the group's representation).
A single group can even have several different representations in terms of matrices. The smallest irreducible representation of the Monster group is as a group of matrices representing rotations in 196,883-dimensional space. The next largest is in 21,296,876-dimensional space, the one after that is in 842,609,326-dimensional space, and there are 194 such representations of the Monster group (including the trivial 1-dimensional one where all elements of the group act like the identity) in all.
NASA's Kepler mission has verified 1,284 new planets – the single largest finding of planets to date.
“This announcement more than doubles the number of confirmed planets from Kepler,” said Ellen Stofan, chief scientist at NASA Headquarters in Washington. “This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”
Analysis was performed on the Kepler space telescope’s July 2015 planet candidate catalog, which identified 4,302 potential planets. For 1,284 of the candidates, the probability of being a planet is greater than 99 percent – the minimum required to earn the status of “planet.” An additional 1,327 candidates are more likely than not to be actual planets, but they do not meet the 99 percent threshold and will require additional study. The remaining 707 are more likely to be some other astrophysical phenomena. This analysis also validated 984 candidates previously verified by other techniques.
"Before the Kepler space telescope launched, we did not know whether exoplanets were rare or common in the galaxy. Thanks to Kepler and the research community, we now know there could be more planets than stars,” said Paul Hertz, Astrophysics Division director at NASA Headquarters. "This knowledge informs the future missions that are needed to take us ever-closer to finding out whether we are alone in the universe."
Kepler captures the discrete signals of distant planets – decreases in brightness that occur when planets pass in front of, or transit, their stars – much like theMay 9 Mercury transit of our sun. Since the discovery of the first planets outside our solar system more than two decades ago, researchers have resorted to a laborious, one-by-one process of verifying suspected planets.
This latest announcement, however, is based on a statistical analysis method that can be applied to many planet candidates simultaneously. Timothy Morton, associate research scholar at Princeton University in New Jersey and lead author of the scientific paper published in The Astrophysical Journal, employed a technique to assign each Kepler candidate a planet-hood probability percentage – the first such automated computation on this scale, as previous statistical techniques focused only on sub-groups within the greater list of planet candidates identified by Kepler.
"Planet candidates can be thought of like bread crumbs,” said Morton. “If you drop a few large crumbs on the floor, you can pick them up one by one. But, if you spill a whole bag of tiny crumbs, you're going to need a broom. This statistical analysis is our broom."
In the newly-validated batch of planets, nearly 550 could be rocky planets like Earth, based on their size. Nine of these orbit in their sun's habitable zone, which is the distance from a star where orbiting planets can have surface temperatures that allow liquid water to pool. With the addition of these nine, 21 exoplanets now are known to be members of this exclusive group.
"They say not to count our chickens before they're hatched, but that's exactly what these results allow us to do based on probabilities that each egg (candidate) will hatch into a chick (bona fide planet)," said Natalie Batalha, co-author of the paper and the Kepler mission scientist at NASA's Ames Research Center in Moffett Field, California. “This work will help Kepler reach its full potential by yielding a deeper understanding of the number of stars that harbor potentially habitable, Earth-size planets -- a number that's needed to design future missions to search for habitable environments and living worlds.”
That the speed of light in free space c is constant has been a pillar of modern physics since the derivation of Maxwell and in Einstein’s postulate in special relativity.
That the speed of light in free space c is constant has been a pillar of modern physics since the derivation of Maxwell and in Einstein’s postulate in special relativity. This has been a basic assumption in light’s various applications. However, a physical beam of light has a finite extent such that even in free space it is by nature dispersive. The field confinement changes its wavevector, hence, altering the light’s group velocity vg. Here, a group of scientists now reports the subluminal vg and consequently the dispersion in free space of Laguerre-Gauss (LG) beam, a beam known to carry orbital angular momentum. The vg of LG beam, calculated in the paraxial regime, is observed to be inversely proportional to the beam’s divergence θ0, the orbital order ℓ and the radial order p. LG beams of higher orders travel relatively slower than that of lower orders. As a consequence, LG beams of different orders separate in the temporal domain along propagation. This is an added effect to the dispersion due to field confinement.
These results are useful for treating information embedded in LG beams from astronomical sources and/or data transmission in free space.
Researchers at Tsinghua University in Beijing have created a mirror-image version of a protein that performs two of the most fundamental processes of life: copying DNA and transcribing it into RNA.
The work is a “small step” along the way to making mirror-image life forms, says molecular biologist Jack Szostak of Harvard Medical School in Boston, Massachusetts. “It’s a terrific milestone,” adds his Harvard colleague George Church, who hopes one day to create an entire mirror-image cell.
Many organic molecules are ‘chiral’: that is, they can exist in mirror-image forms that cannot be superimposed, like a right-handed and left-handed glove. But life almost always employs one version: cells use left-handed amino acids, and have DNA that twists like a right-handed screw, for instance.
Life forms created in this mirrored way would not be able to use any of the biological material of our normal world.
In their research paper, the Tsinghua researchers also present their work as an effort to investigate why life’s chirality is the way it is. This remains mysterious: it may simply be down to chance, or it could have been triggered by a fundamental asymmetry in nature.
But Steven Benner, at the Foundation for Applied Molecular Evolution in Alachua, Florida, says it’s unlikely that creating a mirror form of biochemical life could shed any light on this question. Almost every physical process behaves identically when viewed in a mirror. The only known exceptions — called ‘parity violations’ — lie in the realm of subatomic physics. Such tiny differences would never show up in these biochemical experiments, says Benner. (He is also interested in making DNA that can avoid unwanted degradation by natural enzymes or viruses, but rather than using mirror-DNA, he has created artificial DNA with non-natural building blocks.)
Church’s ultimate goal, to make a mirror-image cell, faces enormous challenges. In nature, RNA is translated into proteins by the ribosome, a complex molecular machine. “Reconstructing a mirror-image of the ribosome would be a daunting task,” says Zhu. Instead, Church is trying to mutate a normal ribosome so that it can handle mirror-RNA.
Church says that it is anyone’s guess as to which approach might pay off. But he notes that a growing number of researchers are working on looking-glass versions of biochemical processes. “For a while it was a non-field,” says Church. “But now it seems very vibrant.”
Sharing genetic information from millions of cancer patients around the world could revolutionize cancer prevention and care, according to a paper in Nature Medicine by the Cancer Task Team of the Global Alliance for Genomics and Health (GA4GH). Hospitals, laboratories and research facilities around the world hold huge amounts of this data from cancer patients, but it’s currently held in isolated “silos” that don’t talk to each other, according to GA4GH, a partnership between scientists, clinicians, patients, and the IT and Life Sciences industry, involving more than 400 organizations in over 40 countries. GA4GH intends to provide a common framework for the responsible, voluntary and secure sharing of patients’ clinical and genomic data.
“Imagine if we could create a searchable cancer database that allowed doctors to match patients from different parts of the world with suitable clinical trials,” said GA4GH co-chair professor Mark Lawler, a leading cancer expert fromQueen’s University Belfast. “This genetic matchmaking approach would allow us to develop personalized treatments for each individual’s cancer, precisely targeting rogue cells and improving outcomes for patients.
“This data sharing presents logistical, technical, and ethical challenges. Our paper highlights these challenges and proposes potential solutions to allow the sharing of data in a timely, responsible and effective manner. We hope this blueprint will be adopted by researchers around the world and enable a unified global approach to unlocking the value of data for enhanced patient care.”
GA4GH acknowledges that there are security issues, and has created a Security Working Group and a policy paper that documents the standards and implementation practices for protecting the privacy and security of shared genomic and clinical data.
Examples of current initiatives for clinico-genomic data-sharing include the U.S.-based Precision Medicine Initiative and the UK’s 100,000 Genomes Project, both of which have cancer as a major focus.
Australian researchers have created a “bionic spinal cord.” They claim that this device could give paralyzed people significant hope of walking again. And if that’s not enough, it could do it utilizing the power of thought and without the necessity of open brain surgery.
Developed under DARPA’s Reliable Neural-Interface Technology (RE-NET) program, the Stentrode can potentially safely expand the use of brain-machine interfaces (BMIs) in the treatment of physical disabilities and neurological disorders.
The researchers describe their “proof-of-concept results” which come from a study conducted on sheep, demonstrating high-fidelity measurements taken from the region of the brain responsible for controlling voluntary movement (called the motor cortex) with the use of the novel device which, as it happens, is just about the size of a paperclip.
Notably, the device records neural activity that has been shown in pre-clinical trials to move limbs through an exoskeleton.
The team, led by neurologist Thomas Oxley, M.D., published their study in an article in the journal Nature Biotechnology.
More than 130 scientists, lawyers, entrepreneurs, and government officials from five continents gathered at Harvard this week for an “exploratory” meeting to discuss the topic of creating genomes from scratch — including, but not limited to, those of humans, said George Church, Harvard geneticist and co-organizer of the meeting. The meeting was closed to the press, which drew the ire of prominent academics.
Synthesizing genomes involves building them from the ground up — chemically combining molecules to create DNA.Similar work by Craig Venter in 2010 created what was hailed as the first synthetic cell, a bacterium with a comparatively small genome.
In recent months, Church has been vocal in saying that the much-hyped genome-editing technology called CRISPR, which is only a few years old and which he helped develop, would soon be obsolete. Instead of changing existing genomes through CRISPR, Church has said, scientists could build exactly the genomes they want from scratch, by stringing together off-the-shelf DNA letters.
The topic is a heavy one, touching on fundamental philosophical questions of meaning and being. If we can build a synthetic genome — and eventually, a creature — from the ground up, then what does it mean to be human?
“This idea is an enormous step for the human species, and it shouldn’t be discussed only behind closed doors,” said Laurie Zoloth, a professor of religious studies, bioethics, and medical humanities at Northwestern University.
In response, she co-authored an article with Drew Endy, a bioengineering professor at Stanford University, calling for broader conversations around the research.
Church said that the meeting was originally going to be “an open meeting with lots of journalists engaged.” It was supposed to be accompanied by a peer-reviewed article on the topic. But, he said, the journal (which Church declined to identify) wanted the paper to include more information about the ethical, social, and legal components of synthesizing genomes — things that were discussed at the meeting.
Physicists at the Swiss Nanoscience Institute and the University of Basel have succeeded in measuring the very weak van der Waals forces between individual atoms for the first time. To do this, they fixed individual noble gas atoms within a molecular network and determined the interactions with a single xenon atom that they had positioned at the tip of an atomic force microscope. As expected, the forces varied according to the distance between the two atoms; but, in some cases, the forces were several times larger than theoretically calculated. These findings are reported by the international team of researchers in Nature Communications.
Van der Waals forces act between non-polar atoms and molecules. Although they are very weak in comparison to chemical bonds, they are hugely significant in nature. They play an important role in all processes relating to cohesion, adhesion, friction or condensation and are, for example, essential for a gecko's climbing skills.
Van der Waals interactions arise due to a temporary redistribution of electrons in the atoms and molecules. This results in the occasional formation of dipoles, which in turn induce a redistribution of electrons in closely neighboring molecules. Due to the formation of dipoles, the two molecules experience a mutual attraction, which is referred to as a van der Waals interaction. This only exists temporarily but is repeatedly re-formed. The individual forces are the weakest binding forces that exist in nature, but they add up to reach magnitudes that we can perceive very clearly on the macroscopic scale - as in the example of the gecko.
To measure the van der Waals forces, scientists in Basel used a low-temperature atomic force microscope with a single xenon atom on the tip. They then fixed the individual argon, krypton and xenon atoms in a molecular network. This network, which is self-organizing under certain experimental conditions, contains so-called nano-beakers of copper atoms in which the noble gas atoms are held in place like a bird egg. Only with this experimental set-up is it possible to measure the tiny forces between microscope tip and noble gas atom, as a pure metal surface would allow the noble gas atoms to slide around.
The researchers compared the measured forces with calculated values and displayed them graphically. As expected from the theoretical calculations, the measured forces fell dramatically as the distance between the atoms increased. While there was good agreement between measured and calculated curve shapes for all of the noble gases analyzed, the absolute measured forces were larger than had been expected from calculations according to the standard model. Above all for xenon, the measured forces were larger than the calculated values by a factor of up to two.
Whether you have a huge honker, a puny proboscis, or a snubbed schnoz, the shape of your nose is in your genes. Now, researchers have sniffed out five of those stretches of DNA that control nose and chin shape. The team sequenced the genomes of more than 6000 men and women in Central and South America and used photographs of the participants to categorize 14 of their facial features—from cheekbone protrusion to lip shape. Then, the scientists analyzed whether any of the features were associated with certain genes. GLI3 and PAX1, both known to be involved in cartilage growth, were linked to the breadth of a person’s nostrils;DCHS2, also related to cartilage, controlled nose pointiness; RUNX2, which drives bone development, was associated with the width of the nose bridge, the upper area of the nose; and EDAR, which has previously been linked to ear and tooth shape and hair texture, affected chin protrusion. The results, published online today in Nature Communications, may help shed light on how the human face evolved and why different ethnicities have distinct facial features. Moreover, the research could help forensic scientists reconstruct faces based on genetic samples.
Some 42 years ago, renowned theoretical physicist Stephen Hawking proposed that not everything that comes in contact with a black hole succumbs to its unfathomable nothingness. Tiny particles of light (photons) are sometimes ejected back out, robbing the black hole of an infinitesimal amount of energy, and this gradual loss of mass over time means every black hole eventually evaporates out of existence.
Known as Hawking radiation, these escaping particles help us make sense of one of the greatest enigmas in the known Universe, but after more than four decades, no one’s been able to actually prove they exist, and Hawking’s proposal remained firmly in hypothesis territory.
But all that could be about to change, with two independent groups of researchers reporting that they’ve found evidence to back up Hawking’s claims, and it could see one of the greatest living physicists finally win a Nobel Prize.
Materials scientists are creating next-generation mixtures with remarkable properties.
At first glance, the machine seems to be building a miniature cityscape. A ring of nozzles fires four jets of powdered metal into a downward-pointed laser beam, which fuses the colliding grains in a bright orange glow. The mixed grains then solidify on the growing tip of a small pillar of metal alloy. Once the pillar is 1–2 centimeters high, the platform that holds it shifts to the side, and the machine starts to build another one right next door. The result looks like a forest of toy skyscrapers.
In reality, these towers, generated at the Ames Laboratory in Iowa, reflect a major shift in how researchers think about alloys. The standard recipe — used for technologies ranging from ancient swords and arrowheads to modern jet-engine turbines — is to take a useful metal and mix in a pinch of this or a touch of that to improve its properties. One classic example is the addition of carbon to iron to make steel.
But the machine at Ames is making experimental samples of 'high-entropy' alloys, which consist of four, five or more elements mixed together in roughly equal ratios. This deceptively simple recipe can yield alloys that are lighter and stronger than their conventional counterparts, while being much more resistant to corrosion, radiation or severe wear. Eventually, researchers hope, this approach could even produce alloys that have magnetic or electrical properties never seen before, leading to whole new generations of technology.
“We have almost explored everything for traditional alloys,” says Yong Zhang, a materials scientist with the State Key Laboratory for Advanced Metals and Materials at the University of Science and Technology Beijing. “For high-entropy alloys, the science is very new,” he says — so new that no such alloy has yet made the leap from lab to market. But some researchers are working to make that happen, eyeing potential applications that range from high-temperature furnace linings to ultralightweight aerospace materials. And the field has attracted funding from research agencies in China, Europe, the United States and elsewhere.
“We're not talking about a narrow class of materials, but an extremely broad philosophy on how to combine elements,” says Daniel Miracle, a materials scientist at the Air Force Research Laboratory at the Wright-Patterson Air Force Base in Ohio. “The opportunity to find something new and exciting is very high.” Last year, he and his colleagues estimated1 that almost 313,560 different alloys can be made by combining exactly equal proportions of 3, 4, 5 or 6 metallic elements from a set of just 26. More possibilities can come from varying the proportions or expanding the choice of elements.
But not every combination is a winner, says Easo George, a materials engineer at Ruhr University Bochum in Germany. Scientists are still learning what works and what doesn't. Still, he says, “the space available for exploration is really huge, and we have only looked at a small portion of the Universe”.
The consumer marketplace is flooded with a lively assortment of smart wearable electronics that do everything from monitor vital signs, fitness or sun exposure to play music, charge other electronics or even purify the air around you - all wirelessly.
Now, a team of University of Wisconsin-Madison engineers has created the world's fastest stretchable, wearable integrated circuits, an advance that could drive the Internet of Things and a much more connected, high-speed wireless world.
Led by Zhenqiang "Jack" Ma, the Lynn H. Matthias Professor in Engineering and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison, the researchers published details of these powerful, highly efficient integrated circuits today, May 27, 2016, in the journal Advanced Functional Materials.
The advance is a platform for manufacturers seeking to expand the capabilities and applications of wearable electronics—including those with biomedical applications—particularly as they strive to develop devices that take advantage of a new generation of wireless broadband technologies referred to as 5G.
With wavelength sizes between a millimeter and a meter, microwave radio frequencies are electromagnetic waves that use frequencies in the .3 gigahertz to 300 gigahertz range. That falls directly in the 5G range.
In mobile communications, the wide microwave radio frequencies of 5G networks will accommodate a growing number of cellphone users and notable increases in data speeds and coverage areas.
In an intensive care unit, epidermal electronic systems (electronics that adhere to the skin like temporary tattoos) could allow health care staff to monitor patients remotely and wirelessly, increasing patient comfort by decreasing the customary tangle of cables and wires.
What makes the new, stretchable integrated circuits so powerful is their unique structure, inspired by twisted-pair telephone cables. They contain, essentially, two ultra-tiny intertwining power transmission lines in repeating S-curves.
This serpentine shape—formed in two layers with segmented metal blocks, like a 3-D puzzle—gives the transmission lines the ability to stretch without affecting their performance. It also helps shield the lines from outside interference and, at the same time, confine the electromagnetic waves flowing through them, almost completely eliminating current loss. Currently, the researchers' stretchable integrated circuits can operate at radio frequency levels up to 40 gigahertz.
And, unlike other stretchable transmission lines, whose widths can approach 640 micrometers (or .64 millimeters), the researchers' new stretchable integrated circuits are just 25 micrometers (or .025 millimeters) thick. That's tiny enough to be highly effective in epidermal electronic systems, among many other applications.
Researchers are coming up with creative ways to pick up biosignatures in far-away planetary atmospheres.
Our galaxy is teeming with planets. Over the last 25 years, astronomers have cataloged about 2,000 worlds in 1,300 systems scattered around our stellar neighborhood. While most of these exoplanets look nothing like Earth (and in some cases, like nothing that orbits our sun), the bonanza of alien worlds implies a tantalizing possibility: There is a lot of real estate out there suitable for life.
We haven’t explored every corner of our solar system. Life might be lurking beneath the surface of some icy satellites or in the soil of Mars. For such locales, we could conceivably visit and look for anything wriggling or replicating. But we can’t travel (yet) to worlds orbiting remote suns dozens of light-years away. An advanced alien civilization might transmit detectable radio signals, but primitive life would not be able to announce its presence to the cosmos.
People have contemplated the possibility of extraterrestrial life since medieval times. We’re still looking for answers today. What would aliens look like? Where should we look to find them? Why are we so obsessed? Science News writers explore these questions and more in this special report.
On Earth, life alters the atmosphere. If plants and critters weren’t around to keep churning out oxygen and methane, those gases would quickly vanish. Water, carbon dioxide, methane, oxygen and ozone are examples of “biosignatures,” key markers of a planet crawling with life as we know it. Setting aside questions about how recognizable alien life might be, detecting biosignatures in the atmosphere of an exoplanet would give astronomers the first strong clue that we are not alone.
Biosignatures aren’t proof of thriving ecosystems. Ultraviolet light from a planet’s sun can zap water molecules and create a stockpile of oxygen; seawater filtering through rocks can produce methane. “We’ll never be able to say 100 percent that a planet has life,” says Sarah Rugheimer, an astrophysicist at the University of St. Andrews in Scotland. But astronomers hope that, given enough information about an exoplanet and the star it orbits, they can build a case for a world where sunlight and geology aren’t enough to explain its chemistry — one where life is a viable possibility. Finding a planet similar to Earth is probably still decades away, but thanks to a couple of upcoming telescopes, astronomers might be on the verge of spying on habitable worlds around nearby stars.
NASA’s Transiting Exoplanet Survey Satellite, or TESS, will launch in 2017 on a quest to detect many of the exoplanets that orbit the stars closest to us. One year later, the James Webb Space Telescope will launch and peek inside some of these newfound atmospheres. With their powers combined, TESS and James Webb could identify nearby planets that are good candidates for life. These worlds will probably be quite different from Earth — they’ll be a bit larger and orbit faint, red suns — but some researchers hope that a few will offer hints of alien biology.
While Earth can have lovely red sunsets, Mars can have a sunset that is truly blue.
Earth has a relatively thick atmosphere, so most of the atmospheric scattering occurs when light strikes a molecule of air, known as Rayleigh scattering. Rayleigh scattering occurs when the object a photon scatters off (the air molecule) is much smaller than the wavelength of the photon. The closer the wavelength is to the size of the molecule, the more likely it is to scatter. This means that red wavelengths (which are the longer wavelengths of visible light) don’t scatter with air molecules much, while blue wavelengths (which are shorter) tend to scatter a lot. In fact blue light is almost 10 times more likely to scatter against air molecules than red light. This is why the sky appears blue, since so much of the blue light is scattered.
When the Sun is low in the sky, it’s light has to travel a long path through the atmosphere to reach you. As the light travels through the atmosphere some of the photons are scattered off the air molecules. When the photons scatter off air molecules, they scatter randomly in all directions, so usually when a photon scatters, it scatters away from your line of sight. Since blue photons scatter much more often than red ones, much of the blue light is scattered away. This leaves red photons to reach your eye. Hence the Sun looks red when low in the sky. When the Sun is overhead, the path it takes to reach you is much shorter, so only a bit of the blue light is scattered. So the Sun looks yellow.
Mars has a much thinner atmosphere, so the amount of Rayleigh scattering is much less. But Mars also has a dry, dusty surface, and a weaker surface gravity, so the atmosphere of Mars is often filled with fine dust particles. These particles are more comparable in size to the wavelengths of visible light, so most of the light is scattered by Mie scattering. One of the main differences between Rayleigh and Mie scattering is that Rayleigh scattering tends to occur in all directions, but Mie scattering varies with scattering angle. What this means is that longer wavelengths (reds) tend to scatter more uniformly, while shorter wavelengths (blues) tend to scatter at slight angles. This means that blue light tends to be deflected less than red light. This means Mars can have a dusty red daytime sky, and a blue sunset.
An international team of scientists has identified a common phenomenon in galaxies that could explain why huge numbers of them turn into cosmic graveyards.
Galaxies begin their existence as lively and colourful spiral galaxies, full of gas and dust, and actively forming bright new stars. However, as galaxies evolve, they quench their star formation and turn into featureless deserts, devoid of fresh new stars, and generally remain as such for the rest of their evolution. But the mechanism that produces this dramatic transformation and keeps galaxies turned off, is one of the biggest unsolved mysteries in galaxy evolution.
Now, thanks to the new large SDSS-IV MaNGA survey of galaxies, a collaborative effort led by the University of Tokyo and involving the University of Oxford has discovered a surprisingly common new phenomenon in galaxies, dubbed "red geysers", that could explain how the process works.
Researchers interpret the red geysers as galaxies hosting low-energy supermassive black holes which drive intense interstellar winds. These winds suppress star formation by heating up the ambient gas found in galaxies and preventing it to cool and condense into stars.
The research will be published in the journal Nature. Lead author Dr Edmond Cheung, from the University of Tokyo's Kavli Institute for the Physics and Mathematics of the Universe, said: 'Stars form from the gas, but in many galaxies stars were found not to form despite an abundance of gas. It was like having deserts in densely clouded regions. We knew quiescent galaxies needed some way to suppress star formation, and now we think the red geysers phenomenon may represent how typical quiescent galaxies maintain their quiescence.'
'Stars form from the gas, a bit like the drops of rain condense from the water vapour. And in both cases one needs the gas to cool down, for condensation to occur. But we could not understand what was preventing this cooling from happening in many galaxies,' said Co-author Dr Michele Cappellari, from the Department of Physics at Oxford University. 'But when we modelled the motion of the gas in the red geysers, we found that the gas was being pushed away from the galaxy centre, and escaping the galaxy gravitational pull.'
'The discovery was made possible by the amazing power of the ongoing MaNGA galaxy survey' said Dr Kevin Bundy, from the University of Tokyo, the overall leader of the collaboration. 'The survey allows us to observe galaxies in three dimensions, by mapping not only how they appear on the sky, but also how their stars and gas move inside them.'
Using a near-dormant distant galaxy named Akira as a prototypical example, the researchers describe how the wind's driving mechanism is likely to originate in Akira's galactic nucleus. The energy input from this nucleus, powered by a supermassive black hole, is capable of producing the wind, which itself contains enough mechanical energy to heat ambient, cooler gas in the galaxy and thus suppress star formation.
Just a few hundred thousand years ago, the Red Planet was hardly that.
Had you searched the sky with a telescope just a few hundred thousand years ago, you would have struggled to find a red planet. Instead, you would have seen a gleaming-white ice ball where Mars should be. A team of astronomers led by Isaac Smith, an astrophysicist at the Southwest Research Institute in Boulder, Colorado, has collected the first concrete evidence that Mars has just exited an extreme ice age, one so intense it would have put Earth's recent frosty foray to shame.
Using cameras and a radar-pinging device on board NASA's Mars Reconnaissance Orbiter, Smith's team deduced this history by dating the miles-deep layers of snow and ice packed onto the Red Planet's northern pole. They found that only a mere 370,000 years ago, "Mars would have actually looked more white than red," says Smith. The Mars research is outlined today in the journal Science.
University of Virginia School of Medicine have discovered that a gene called Oct4 — which scientific dogma insists is inactive in adults — actually plays a vital role in preventing ruptured atherosclerotic plaques inside blood vessels, the underlying cause of most heart attacks and strokes.
The researchers found that Oct4 controls the conversion of smooth muscle cells into protective fibrous “caps” inside plaques, making the plaques less likely to rupture. They also discovered that the gene promotes many changes in gene expression that are beneficial in stabilizing the plaques. In addition, the researchers believe it may be possible to develop drugs or other therapeutic agents that target the Oct4 pathway as a way to reduce the incidence of heart attacks or stroke.
The researchers are also currently testing Oct4′s possible role in repairing cellular damage and healing wounds, which would make it useful for regenerative medicine.
Oct4 is one of the “stem cell pluripotency factors” described by Shinya Yamanaka, PhD, of Kyoto University, for which he received the 2012 Nobel Prize. His lab and many others have shown that artificial over-expression of Oct4 within somatic cells grown in a lab dish is essential for reprogramming these cells into induced pluripotential stem cells, which can then develop into any cell type in the body or even an entire organism.
“Finding a way to reactivate this pathway may have profound implications for health and aging,” said researcher Gary K. Owens, director of UVA’s Robert M. Berne Cardiovascular Research Center. “This could impact many human diseases and the field of regenerative medicine. [It may also] end up being the ‘fountain-of-youth gene,’ a way to revitalize old and worn-out cells.”
Alison L. Van Eenennaam, PhD, a geneticist and cooperative extension specialist also at UC-Davis, is working with the Minnesota-based company Recombinetics on, among other things, a project that has produced some of the Holstein dairy cattle that lack horns by editing one allele to match another found in Angus cattle.
“We’ve still got a dairy cow with all the good dairy genetics,” she said. “We’ve just gone in and tweaked a little snippet of DNA at the gene that makes horns and made it so it’s the variant for Angus, which doesn’t grow horns.”
The effects of this sudden release of particles and energy have been observed throughout the solar system and beyond.
In a first, the US space agency has directly observed fundamental process of nature after sending four spacecraft through an invisible whirlpool in space called magnetic reconnection, like sending sensors up into a hurricane. The findings showed that magnetic reconnection is dominated by the physics of electrons - thus providing crucial information about what powers this fundamental process in nature.
Magnetic reconnection is one of the prime drivers of space radiation and a key factor in the quest to learn more about our space environment and protect our spacecraft and astronauts. The effects of this sudden release of particles and energy - such as giant eruptions on the sun or radiation storms in near-Earth space - have been observed throughout the solar system and beyond.
"We developed a mission called the Magnetospheric Multiscale mission (MMS) that for the first time would have the precision needed to gather observations in the heart of magnetic reconnection," said Jim Burch, principal investigator at the Southwest Research Institute in San Antonio, Texas.
"We received results faster than we could have expected. By seeing magnetic reconnection in action, we have observed one of the fundamental forces of nature," he added. MMS is made of four identical spacecraft that were launched in March 2015. They fly in a pyramid formation to create a full 3D map of any phenomena they observe.
On October 16, 2015, the spacecraft travelled straight through a magnetic reconnection event at the boundary where Earth's magnetic field bumps up against the sun's magnetic field.
In only a few seconds, the 25 sensors on each of the spacecraft collected thousands of observations. By watching these electrons, MMS made the first observation of the predicted breaking and interconnection of magnetic fields in space.
"The data showed the entire process of magnetic reconnection to be fairly orderly and elegant," said Michael Hesse, space scientist at Goddard, in a paper published in the journal Science. There does not seem to be much turbulence present, or at least not enough to disrupt or complicate the process.
This suggests that it is the physics of electrons that is at the heart of understanding how magnetic field lines accelerate the particles.
Since its launch, MMS has made more than 4,000 trips through the magnetic boundaries around Earth, each time gathering information about the way the magnetic fields and particles move.
The promise of short interfering RNA (siRNA) is that it can be harnessed to turn off harmful genes in the cell. The difficulty is getting siRNA into the cell in the first place. In a new approach, nanoengineers have driven siRNA into the cell on acoustically-propelled nanomotors, silencing genes faster and more completely than with current methods (ACS Nano2016, DOI: 10.1021/acsnano.6b01415).
To silence a gene, researchers tap the cell’s own gene suppression system, which quashes the RNA messengers that are produced when a DNA sequence is expressed. The messengers are knocked out by siRNA, complementary to a given messenger RNA, which binds the mRNA and prevents it from being translated into a protein. Scientists can mooch off the cell’s gene suppression infrastructure simply by inserting an engineered siRNA specific to a target into the cell.
But that’s easier said than done. The negatively charged siRNA has to cross a negatively-charged cell membrane, traverse the intracellular milieu, and bump into the cell’s silencing complex before degradation enzymes destroy it.
The delivery challenge has spawned a bounty of possible siRNA carriers: metal particles, lipid bubbles, hydrogels, and more. Most of these strategies rely on some form of chemical camouflage to enter the cell and on diffusion to do the rest. But Yi Chen and Joseph Wang of the University of California, San Diego, thought that ultrasound-propelled nanowires might produce an siRNA transporter with more oomph.
When bombarded with ultrasound, these tiny gold rods—about 4 μm long, 200 nm in diameter, and concave at one end—scurry into motion. They penetrate cells, bounce around like pinballs, and even spin.
“Angular momentum measures how much something is rotating,” one of the study’s researchers, Kyle Ballantine, told Trinity News. “For a beam of light, although traveling in a straight line it can also be rotating around its own axis.” Up until this finding, physicists thought the angular momentum of all forms of light was a multiple of Planck’s constant. Apparently, that’s not so.
To uncover this information, the researchers began by searching for new behaviors of light by shining beams through crystals to create “screw-like structures.” They used the theory of quantum mechanics to analyze these beam structures and realized that the angular momentum of the photon would be a half-integer, not a multiple of Planck’s constant.
This discovery might not sound like much, but researchers suggest that it will influence our knowledge about the very essence of light. “Our discovery will have real impacts for the study of light waves in areas such as secure optical communications,” Professor John Donegan said.
Finding a new form of light is undoubtedly exciting. However, much of the physics community’s real joy comes from validating 30-year-old theoretical physics predictions. In the 1980s, physicists speculated ways in which quantum mechanics would open doors for strange new discoveries, such as particles with fractions of their expected quantum numbers. This research provides the first validation of those predictions. “This discovery is a breakthrough for the world of physics and science alike,” said CRANN Director, Stefano Santo.
Earth’s continuously changing magnetic field is thought to be largely generated by superheated, swirling liquid iron in Earth’s outer core. Other sources of earthly magnetism include minerals in our world’s mantle and crust.
Earth’s ionosphere, magnetosphere and oceans also play a role. The European Space Agency (ESA) now has two years of data from a trio of satellites in Earth-orbit, designed to measure magnetism from these various sources. The mission is called Swarm. At last week’s Living Planet Symposium held in Prague in the Czech Republic (May 9-13, 2016), scientists presented new results from the Swarm satellite trio and provided some recent insights about how Earth’s magnetic field is changing at this time.
Among other things, they said that the field has weakened by about 3.5% at high latitudes over North America, while it has grown about 2% stronger over Asia. The region where the field is at its weakest field – the South Atlantic Anomaly – has moved steadily westward and further weakened by about 2%.
Meanwhile, the magnetic north pole has been wandering east, towards Asia. The animation shown in this article is based partly on results from ESA’s Swarm mission, and partly on information from the CHAMP and Ørsted satellites. It shows how the strength of Earth’s magnetic field changed between 1999 and mid-2016. Blue depicts where the field is weak and red shows regions where the field is strong. As you can see, the changes in field strength are relatively small.
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