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Cracked metal heals itself: Unexpected result shows that pulling apart makes cracks in metal fuse together

Cracked metal heals itself: Unexpected result shows that pulling apart makes cracks in metal fuse together | Amazing Science |

It was a result so unexpected that MIT researchers initially thought it must be a mistake: Under certain conditions, putting a cracked piece of metal under tension — that is, exerting a force that would be expected to pull it apart — has the reverse effect, causing the crack to close and its edges to fuse together.

The surprising finding could lead to self-healing materials that repair incipient damage before it has a chance to spread. The results were published in the journal Physical Review Letters in a paper by graduate student Guoqiang Xu and professor of materials science and engineering Michael Demkowicz.

“We had to go back and check,” Demkowicz says, when “instead of extending, [the crack] was closing up. First, we figured out that, indeed, nothing was wrong. The next question was: ‘Why is this happening?’”

The answer turned out to lie in how grain boundaries interact with cracks in the crystalline microstructure of a metal — in this case nickel, which is the basis for “superalloys” used in extreme environments, such as in deep-sea oil wells.

By creating a computer model of that microstructure and studying its response to various conditions, “We found that there is a mechanism that can, in principle, close cracks under any applied stress,” Demkowicz says. 

Most metals are made of tiny crystalline grains whose sizes and orientations can affect strength and other characteristics. But under certain conditions, Demkowicz and Xu found, stress “causes the microstructure to change: It can make grain boundaries migrate. This grain boundary migration is the key to healing the crack,” Demkowicz says.

The very idea that crystal grain boundaries could migrate within a solid metal has been extensively studied within the last decade, Demkowicz says. Self-healing, however, occurs only across a certain kind of boundary, he explains — one that extends partway into a grain, but not all the way through it. This creates a type of defect is known as a “disclination.”

Disclinations were first noticed a century ago, but had been considered “just a curiosity,” Demkowicz says. When he and Xu found the crack-healing behavior, he says, “it took us a while to convince ourselves that what we’re seeing are actually disclinations.”

These defects have intense stress fields, which “can be so strong, they actually reverse what an applied load would do,” Demkowicz says: In other words, when the two sides of a cracked material are pulled apart, instead of cracking further, it can heal. “The stress from the disclinations is leading to this unexpected behavior,” he says.

Having discovered this mechanism, the researchers plan to study how to design metal alloys so cracks would close and heal under loads typical of particular applications. Techniques for controlling the microstructure of alloys already exist, Demkowicz says, so it’s just a matter of figuring out how to achieve a desired result.

“That’s a field we’re just opening up,” he says. “How do you design a microstructure to self-heal? This is very new.” 

The technique might also apply to other kinds of failure mechanisms that affect metals, such as plastic flow instability — akin to stretching a piece of taffy until it breaks. Engineering metals’ microstructure to generate disclinations could slow the progression of this type of failure, Demkowicz says.

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

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Saberes Sin Fronteras OVS's curator insight, November 30, 2014 5:33 PM

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Bringing neural networks to cellphones

Bringing neural networks to cellphones | Amazing Science |

In recent years, the best-performing artificial-intelligence systems — in areas such as autonomous driving, speech recognition, computer vision, and automatic translation — have come courtesy of software systems known as neural networks.


But neural networks take up a lot of memory and consume a lot of power, so they usually run on servers in the cloud, which receive data from desktop or mobile devices and then send back their analyses.


Last year, MIT associate professor of electrical engineering and computer science Vivienne Sze and colleagues unveiled a new, energy-efficient computer chip optimized for neural networks, which could enable powerful artificial-intelligence systems to run locally on mobile devices.


Now, Sze and her colleagues have approached the same problem from the opposite direction, with a battery of techniques for designing more energy-efficient neural networks. First, they developed an analytic method that can determine how much power a neural network will consume when run on a particular type of hardware. Then they used the method to evaluate new techniques for paring down neural networks so that they’ll run more efficiently on handheld devices.


The researchers describe the work in a paper they’re presenting next week at the Computer Vision and Pattern Recognition Conference. In the paper, they report that the methods offered as much as a 73 percent reduction in power consumption over the standard implementation of neural networks, and as much as a 43 percent reduction over the best previous method for paring the networks down.

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Neural stem cells steered by electric fields can repair brain damage

Neural stem cells steered by electric fields can repair brain damage | Amazing Science |

Limited migration of neural stem cells in adult brain is a roadblock for the use of stem cell therapies to treat brain diseases and injuries. Here, scientists report a strategy that mobilizes and guides migration of stem cells in the brain in vivo. They developed a safe stimulation paradigm to deliver directional currents in the brain. Tracking cells expressing GFP demonstrated electrical mobilization and guidance of migration of human neural stem cells, even against co-existing intrinsic cues in the rostral migration stream. Transplanted cells were observed at 3 weeks and 4 months after stimulation in areas guided by the stimulation currents, and with indications of differentiation. Electrical stimulation thus may provide a potential approach to facilitate brain stem cell therapies.

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Human liver cells seeded in mouse expands 50-fold to functional organoid

Human liver cells seeded in mouse expands 50-fold to functional organoid | Amazing Science |

Scientists worked out the cellular assembly for seeding a whole new organ. To grow a liver, researchers led by MIT engineer Sangeeta Bhatia started by carefully designing a cellular scaffold for the organ to grow on. They first got human liver cells (hepatocytes) and connective tissue cells (fibroblasts) to grow together in clumps. Then they used a micro-tissue molding to create ropes endothelial cells, which make up the lining of blood and lymphatic vessels. Last, they carefully assembled rows of the cell clumps in between strands of endothelial chords and held the structure together with a biodegradable hydrogel.


In all, they called the organ starter kit SEED, for “In Situ Expansion of Engineered Devices.” To test out the SEEDs, the researchers implanted them into the belly fat of healthy mice and mice with a genetic disorder that causes liver damage.  In the healthy mice, the liver seeds didn’t grow very much. But in the rodents with liver damage—which were circulating liver-regenerating growth factors and other molecular signals to repair their damaged liver—the organ SEEDs sprouted.


Eighty days after implantation, there was a 50-fold cellular expansion along the SEED’s scaffold. The liver organoid formed precursor bile ducts and contained clusters of red blood cells, suggesting vasculature formation. The organoid also pumped out standard human liver proteins, including albumin and transferrin.


There’s a lot more work to go before researchers have a human-sized, functional liver, but the team is optimistic. “We believe that this work sets the stage for using SEEDs as an alternative strategy for scale-up of engineered organs, one that uses native developmental, injury, or regenerative signals to expand prefabricated constructs in situ,” they conclude.


Stevens et al., Science Translational Medicine (2017). DOI: 10.1126/scitranslmed.aah5505 (About DOIs).

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Projecting a visual image directly into the brain, bypassing the eyes

Projecting a visual image directly into the brain, bypassing the eyes | Amazing Science |
Imagine replacing a damaged eye with a window directly into the brain — one that communicates with the visual part of the cerebral cortex by reading from a million individual neurons and simultaneously stimulating 1,000 of them with single-cell accuracy, allowing someone to see again.

That’s the goal of a $21.6 million DARPA award to the University of California, Berkeley (UC Berkeley), one of six organizations funded by DARPA’s Neural Engineering System Design program announced this week to develop implantable, biocompatible neural interfaces that can compensate for visual or hearing deficits.*

The UCB researchers ultimately hope to build a device for use in humans. But the researchers’ goal during the four-year funding period is more modest: to create a prototype to read and write to the brains of model organisms — allowing for neural activity and behavior to be monitored and controlled simultaneously. These organisms include zebrafish larvae, which are transparent, and mice, via a transparent window in the skull.


“The ability to talk to the brain has the incredible potential to help compensate for neurological damage caused by degenerative diseases or injury,” said project leader Ehud Isacoff, a UC Berkeley professor of molecular and cell biology and director of the Helen Wills Neuroscience Institute. “By encoding perceptions into the human cortex, you could allow the blind to see or the paralyzed to feel touch.”


To communicate with the brain, the team will first insert a gene into neurons that makes fluorescent proteins, which flash when a cell fires an action potential. This will be accompanied by a second gene that makes a light-activated “optogenetic” protein, which stimulates neurons in response to a pulse of light.


To read, the team is developing a miniaturized “light field microscope.” Mounted on a small window in the skull, it peers through the surface of the brain to visualize up to a million neurons at a time at different depths and monitor their activity. This microscope is based on the revolutionary “light field camera,” which captures light through an array of lenses and reconstructs images computationally in any focus.


The combined read-write function will eventually be used to directly encode perceptions into the human cortex — inputting a visual scene to enable a blind person to see. The goal is to eventually enable physicians to monitor and activate thousands to millions of individual human neurons using light.


Isacoff, who specializes in using optogenetics to study the brain’s architecture, can already successfully read from thousands of neurons in the brain of a larval zebrafish, using a large microscope that peers through the transparent skin of an immobilized fish, and simultaneously write to a similar number.


The team will also develop computational methods that identify the brain activity patterns associated with different sensory experiences, hoping to learn the rules well enough to generate “synthetic percepts” — meaning visual images representing things being touched — by a person with a missing hand, for example. This technology has a lot of potential in the future.

Donald Schwartz's curator insight, July 18, 7:08 PM

Science fiction no more. Now this is what I call visualization.

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Why Do Corals Glow in the Dark? A new study suggests they use fluorescence for photosynthesis

Why Do Corals Glow in the Dark? A new study suggests they use fluorescence for photosynthesis | Amazing Science |

It’s one of the ocean’s most beautiful and striking mysteries: Why do corals fluoresce? In shallow waters, they glow a brilliant pink and purple. In deeper waters, corals turn red and green against a dim blue background. The view is most unforgettable at night with a flashlight and mask filter, when the fluorescent corals provide a “psychedelic adventure.”


Jörg Wiedenmann, a coral reef scientist at University of Southampton, had previously found that the pink and purple fluorescence in shallow waters act as a kind of sunscreen. The fluorescent pigments absorb damaging wavelengths of light and emit it as pink or purple light, protecting the single-celled organisms called zooxanthellae that live symbiotically inside coral. Zooxanthellae are photosynthetic and they provide the coral with food in exchange for shelter.


This “sunscreen” effect was interesting, but it didn’t explain why corals fluoresce in deeper water, where light was not intense enough to harm zooxanthellae. In fact, in those dim blue waters, the problem was more likely too little light. Wiedenmann and his colleagues now have a new study, in which they present a novel function for deep water fluorescence. And again, it has to do with the zooxanthellae: Coral may be converting blue light into orange-red light that penetrates deeper into the coral tissue, where photosynthetic zooxanthellae live. Fluorescence, by definition, is the absorption of light in one color and the emission in another.

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Switchable DNA mini-machines store information: They change shape in a cascade

Switchable DNA mini-machines store information: They change shape in a cascade | Amazing Science |
Biomedical engineers have built simple machines out of DNA, consisting of arrays whose units switch reversibly between two different shapes. The arrays' inventors say they could be harnessed to make nanotech sensors or amplifiers. Potentially, they could be combined to form logic gates, the parts of a molecular computer.


The arrays' inventors say they could be harnessed to make nanotech sensors or amplifiers. Potentially, they could be combined to form logic gates, the parts of a molecular computer.

The arrays' properties are scheduled for publication online by Science. The DNA machines can relay discrete bits of information through space or amplify a signal, says senior author Yonggang Ke, PhD, an assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory.


"In the field of DNA-based computing, the DNA contains the information, but the molecules are floating around in solution," Ke says. "What's new here is that we are linking the parts together in a physical machine."


Similarly, several laboratories have already made nanotech machines such as tweezers and walkers out of DNA. Ke says his team's work with DNA arrays sheds light on how to build structures with more complex, dynamic behaviors.


The arrays' structures look like accordion-style retractable security gates. Extending or contracting one unit pushes nearby units to change shape as well, working like a domino cascade whose tiles are connected. The arrays' units get their stability from the energy gained when DNA double helices stack up. To be stable, the units' four segments can align as pairs side by side in two different orientations. By leaving out one strand of the DNA at the edge of an array, the engineers create an external trigger. When that strand is added, it squeezes the edge unit into changing shape.


To visualize the DNA arrays, the engineers used atomic force microscopy. They built rectangular 11x4 and 11x7 arrays, added trigger strands and could observe the cascade propagate from the corner unit to the rest of the array. The arrays' cascades can be stopped or resumed at selected locations by designing break points into the arrays. The units' shape conversions are modulated by temperature or chemical denaturants.


For reference, the rectangular arrays are around 50 nanometers wide and a few hundred nanometers long -- slightly smaller than a HIV or influenza virion.

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Solar paint offers endless energy from water vapor: Compound catalyses splitting of water molecules

Solar paint offers endless energy from water vapor: Compound catalyses splitting of water molecules | Amazing Science |
Researchers have developed a compound that draws moisture from the air and splits it into oxygen and hydrogen. The hydrogen can be captured as a clean fuel source.


The paint contains a newly developed compound that acts like silica gel, which is used in sachets to absorb moisture and keep food, medicines and electronics fresh and dry. But unlike silica gel, the new material, synthetic molybdenum-sulphide, also acts as a semi-conductor and catalyses the splitting of water molecules into hydrogen and oxygen.


Lead researcher Dr Torben Daeneke, from RMIT University in Melbourne, Australia, said: "We found that mixing the compound with titanium oxide particles leads to a sunlight-absorbing paint that produces hydrogen fuel from solar energy and moist air.


"Titanium oxide is the white pigment that is already commonly used in wall paint, meaning that the simple addition of the new material can convert a brick wall into energy harvesting and fuel production real estate. "Our new development has a big range of advantages," he said. "There's no need for clean or filtered water to feed the system. Any place that has water vapor in the air, even remote areas far from water, can produce fuel." Watch the video: colleague, Distinguished Professor Kourosh Kalantar-zadeh, said hydrogen was the cleanest source of energy and could be used in fuel cells as well as conventional combustion engines as an alternative to fossil fuels. "This system can also be used in very dry but hot climates near oceans. The sea water is evaporated by the hot sunlight and the vapor can then be absorbed to produce fuel.


"This is an extraordinary concept -- making fuel from the sun and water vapor in the air."

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Astronomers Detect Orbital Motion in Pair of Supermassive Black Holes

Astronomers Detect Orbital Motion in Pair of Supermassive Black Holes | Amazing Science |
VLBA images detect orbital motion of two supermassive black holes as they circle each other at the center of a distant galaxy.


Using the supersharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA), astronomers have made the first detection of orbital motion in a pair of supermassive black holes in a galaxy some 750 million light-years from Earth. The two black holes, with a combined mass 15 billion times that of the Sun, are likely separated by only about 24 light-years, extremely close for such a system.


"This is the first pair of black holes to be seen as separate objects that are moving with respect to each other, and thus makes this the first black-hole 'visual binary,'" said Greg Taylor, of the University of New Mexico (UNM). Supermassive black holes, with millions or billions of times the mass of the Sun, reside at the cores of most galaxies. The presence of two such monsters at the center of a single galaxy means that the galaxy merged with another some time in the past. In such cases, the two black holes themselves may eventually merge in an event that would produce gravitational waves that ripple across the universe.


"We believe that the two supermassive black holes in this galaxy will merge," said Karishma Bansal, a graduate student at UNM, adding that the merger will come at least millions of years in the future. The galaxy, an elliptical galaxy called 0402+379, after its location in the sky, was first observed in 1995. It was studied in 2003 and 2005 with the VLBA. Based on finding two cores in the galaxy, instead of one, Taylor and his collaborators concluded in 2006 that it contained a pair of supermassive black holes.


The latest research, which Taylor and his colleagues are reporting in the Astrophysical Journal, incorporates new VLBA observations from 2009 and 2015, along with re-analysis of the earlier VLBA data. This work revealed motion of the two cores, confirming that the two black holes are orbiting each other. The scientists' initial calculations indicate that they complete a single orbit in about 30,000 years.

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The multi-colored photons that might change quantum information science

The multi-colored photons that might change quantum information science | Amazing Science |

With leading corporations now investing in highly expensive and complex infrastructures to unleash the power of quantum technologies, INRS researchers have achieved a breakthrough in a light-weight photonic system created using on-chip devices and off-the-shelf telecommunications components. In their paper published in Nature, the team demonstrates that photons can become an accessible and powerful quantum resource when generated in the form of color-entangled quDits.


The system uses a small and cost-effective photonic chip fabricated through processes similar to those used for integrated electronics. With an on-chip micro-ring resonator excited by a laser, photons are emitted in pairs that share a complex quantum state. The photons are constructed in a state featuring a number of superimposed frequency components: The photons have several colors simultaneously, and the colors of each photon in a pair are linked (entangled), regardless of their separation distance.


With each frequency -- or color -- representing a dimension, the photons are generated on-chip as a high-dimensional quantum state (quDit). Thus far, quantum information science has largely focused on the exploitation of qubits, based on two-dimensional systems where two states are superimposed (for example, 0 AND 1 at the same time, in contrast to classical bits, which are 0 OR 1 at any time). Working in the frequency domain allows the superposition of many more states (for example, a high-dimensional photon can be red AND yellow AND green AND blue, although the photons used here were infrared for telecommunications compatibility), enhancing the amount of information in a single photon.


To date, Professor Roberto Morandotti, who leads the INRS research team, confirms the realization of a quantum system with at least one hundred dimensions using this approach, and the technology developed is readily extendable to create two-quDit systems with more than 9,000 dimensions (corresponding to 12 qubits and beyond, comparable to the state of the art in significantly more expensive/complex platforms). 


The use of the frequency domain for such quantum states enables their easy transmission and manipulation in optical fibre systems. "By merging the fields of quantum optics and ultrafast optical processing, we have shown that high-dimensional manipulation of these states is indeed possible using standard telecommunications elements like modulators and frequency filters," stresses telecommunications system expert Professor José Azaña, co-supervisor of the conducted research.

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Genes change locations: Growing cells remix their genes

Genes change locations: Growing cells remix their genes | Amazing Science |

Moving genes about could help cells to respond to change according to scientists at the Babraham Institute in Cambridge, UK and the Weizmann Institute, Israel. Changing the location of a gene within a cell alters its activity. Like mixing music, different locations can make a gene ‘louder’ or ‘quieter’, with louder genes contributing more actively to the life of a cell.

Contrary to expectations, this latest study reveals that each gene doesn’t have an ideal location in the cell nucleus. Instead, genes are always on the move. Published in the journal Nature, researchers examined the organisation of genes in stem cells from mice. They revealed that these cells continually remix their genes, changing their positions as they progress though different stages. This work, which has also inspired a musical collaboration, suggests that moving genes about in this way could help cells to fine-tune the volume of each gene to suit the cell’s needs.

Scientists had believed that the location of genes in cells are relatively fixed with each gene having it’s rightful place. Different types of cells could organise their genes in different ways, but genes weren’t thought to move around much except when cells divide. This is the first time that gene organisation in individual cells has been studied in detail. The results provide snapshots of gene organisation, with each cell arranging genes in unique ways.

Co-first authors, Dr Takashi Nagano in the UK and Yaniv Lubling in Israel have collected and individually analysed information one-by-one from over 4000 cells for this study. Speaking about the work, Dr Nagano said: “We’ve never had access to this level of information about how genes are organised before. Being able to compare between thousands of individual cells is an extremely powerful tool and adds an important dimension to our understanding of how cells position their genes.”

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Untreatable gonorrhoea on the rise worldwide

Untreatable gonorrhoea on the rise worldwide | Amazing Science |

Gonorrhoea is becoming as incurable as it was in the 1920s, before the first drugs to treat it were discovered. More than 60% of countries surveyed around the world have reported cases that resist last-resort antibiotics, according to an announcement by the World Health Organization (WHO) on 6 July, 2017. The announcement included information about a new gonorrhoea drug in development.


Since the 1930s, several classes of antibiotics have been used to kill the bacterium that causes gonorrhoea, Neisseria gonorrhoeae. Widespread use — and misuse — of these drugs, however, has led to a rise of antibiotic-resistant strains of the bacteria. “The best time to have had gonorrhoea was the eighties, since there were many drugs to treat it with,” says Ramanan Laxminarayan, director of the Center for Disease Dynamics, Economics and Policy in Washington DC. Increasingly, that's no longer the case, he says.


Health agencies in the United States, Europe and Canada have in recent years flagged drug-resistant gonorrhoea as an emerging threat. If left untreated, gonorrhoea can increase a woman’s risk of developing HIV infection, infertility or ectopic pregnancy — among other effects. When the WHO partnered with the Drugs for Neglected Diseases initiative (DNDi), a non-governmental organization in Geneva, Switzerland, in May 2016 to confront antimicrobial resistance, gonorrhoea was at the top of the list.

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In a Lost Baby Tooth, Scientists Find Ancient Denisovan DNA

In a Lost Baby Tooth, Scientists Find Ancient Denisovan DNA | Amazing Science |

More than 100,000 years ago in a Siberian cave there lived a child with a loose tooth. One day her molar fell out, and fossilized over many millenniums, keeping it safe from the elements and the tooth fairy.


But she wasn’t just any child. Scientists say she belonged to a species of extinct cousins of Neanderthals and modern humans known today as the Denisovans. And in a paper published Friday in the journal Science Advances, a team of paleoanthropologists reported that she is only the fourth individual of this species ever discovered.


“We only have relatively little data from this archaic group, so having any additional individuals is something we’re very excited about,” saidViviane Slon, a doctoral candidate at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and lead author of the study.


The scant fossil record for these ancient hominins previously included only two adult molars and a finger bone. The Denisovans were only correctly identified in 2010 by a team of researchers led by Svante Paabo, who used the finger bone to sequence the species’ genome.

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UMMC Implants the Worlds Smallest Pacemaker

UMMC Implants the Worlds Smallest Pacemaker | Amazing Science |

The University of Maryland Medical Center’s Stephen Shorofsky, MD, PhD, was one of the first doctors in Maryland to implant the world’s smallest pacemaker for patients with bradycardia.


Recently approved by the U.S. Food and Drug Administration (FDA), the Micra® Transcatheter Pacing System (TPS) is a new type of heart device that provides patients with the most advanced pacing technology at one-tenth the size of a traditional pacemaker.


Micra is the only leadless pacemaker approved for use in the U.S. Bradycardia is a condition characterized by a slow or irregular heart rhythm. As a result, the heart is unable to pump enough oxygen-rich blood to the body during normal activity or exercise, causing dizziness, fatigue, shortness of breath or fainting spells. Pacemakers are the most common way to treat bradycardia to help restore the heart's normal rhythm and relieve symptoms by sending electrical impulses to the heart to increase the heart rate.


Comparable in size to a large vitamin, physicians at UMMC have elected to use the Medtronic Micra TPS because unlike traditional pacemakers, the device does not require cardiac wires (leads) or a surgical “pocket” under the skin to deliver a pacing therapy. Instead, the device is small enough to be delivered through a catheter and implanted directly into the heart with small tines, providing a safe alternative to conventional pacemakers without the complications associated with leads – all while being cosmetically invisible. The Micra TPS is also designed to automatically adjust pacing therapy based on a patient’s activity levels.

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How to turn audio clips into realistic lip-synced video

How to turn audio clips into realistic lip-synced video | Amazing Science |

University of Washington researchers at the UW Graphics and Image Laboratory have developed new algorithms thatturn audio clips into a realistic, lip-synced video, starting with an existing video of  that person speaking on a different topic.


As detailed in a paper to be presented Aug. 2 at  SIGGRAPH 2017, the team successfully generated a highly realistic video of former president Barack Obama talking about terrorism, fatherhood, job creation and other topics, using audio clips of those speeches and existing weekly video addresses in which he originally spoke on a different topic decades ago.


Realistic audio-to-video conversion has practical applications like improving video conferencing for meetings (streaming audio over the internet takes up far less bandwidth than video, reducing video glitches), or holding a conversation with a historical figure in virtual reality, said Ira Kemelmacher-Shlizerman, an assistant professor at the UW’s Paul G. Allen School of Computer Science & Engineering.

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Is anyone home? A way to find out if AI has become self-aware

Is anyone home? A way to find out if AI has become self-aware | Amazing Science |

Based on this essential characteristic of consciousness, a new test for machine consciousness, the AI Consciousness Test (ACT), has been developed. It looks at whether the synthetic minds created have an experience-based understanding of the way it feels, from the inside, to be conscious.


One of the most compelling indications that normally functioning humans experience consciousness, although this is not often noted, is that nearly every adult can quickly and readily grasp concepts based on this quality of felt consciousness. Such ideas include scenarios like minds switching bodies (as in the film Freaky Friday); life after death (including reincarnation); and minds leaving “their” bodies (for example, astral projection or ghosts). Whether or not such scenarios have any reality, they would be exceedingly difficult to comprehend for an entity that had no conscious experience whatsoever. It would be like expecting someone who is completely deaf from birth to appreciate a Bach concerto. Thus, the ACT would challenge an AI with a series of increasingly demanding natural language interactions to see how quickly and readily it can grasp and use concepts and scenarios based on the internal experiences we associate with consciousness. At the most elementary level we might simply ask the machine if it conceives of itself as anything other than its physical self.


At a more advanced level, AI researchers might see how it deals with ideas and scenarios such as those mentioned in the previous paragraph. At an advanced level, its ability to reason about and discuss philosophical questions such as “the hard problem of consciousness” would be evaluated. At the most demanding level, they might see if the machine invents and uses such a consciousness-based concept on its own, without relying on human ideas and inputs.


Consider this example, which illustrates the idea: Suppose one finds a planet that has a highly sophisticated silicon-based life form (call them “Zetas”). Scientists observe them and ponder whether they are conscious beings. What would be convincing proof of consciousness in this species? If the Zetas express curiosity about whether there is an afterlife or ponder whether they are more than just their physical bodies, it would be reasonable to judge them conscious. If the Zetas went so far as to pose philosophical questions about consciousness, the case would be stronger still.


There are also nonverbal behaviors that could indicate Zeta consciousness such as mourning the dead, religious activities or even turning colors in situations that correlate with emotional challenges, as chromatophores do on Earth. Such behaviors could indicate that it feels like something to be a Zeta.


The death of the mind of the fictional HAL 9000 AI computer in Stanley Kubrick’s 2001: A Space Odyssey provides another illustrative example. The machine in this case is not a humanoid robot as in most science fiction depictions of conscious machines; it neither looks nor sounds like a human being (a human did supply HAL’s voice, but in an eerily flat way). Nevertheless, the content of what it says as it is deactivated by an astronaut — specifically, a plea to spare it from impending “death” — conveys a powerful impression that it is a conscious being with a subjective experience of what is happening to it.

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High-temperature superconductivity in B-doped Q-carbon

High-temperature superconductivity in B-doped Q-carbon | Amazing Science |

Researchers at North Carolina State University have significantly increased the temperature at which carbon-based materials act as superconductors, using a novel, boron-doped Q-carbon material. The previous record for superconductivity in boron-doped diamond was 11 Kelvin, or minus 439.60 degrees Fahrenheit. The boron-doped Q-carbon has been found to be superconductive from 37K to 57K, which is minus 356.80 degrees F.

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The Resilience of Life to Astrophysical Events

The Resilience of Life to Astrophysical Events | Amazing Science |

Much attention has been given in the literature to the effects of astrophysical events on human and land-based life. However, little has been discussed on the resilience of life itself. A group of scientists now speculates about the statistics of events that completely sterilize an Earth-like planet with planet radii in the range 0.5–1.5R and temperatures of 300 K, eradicating all forms of life. They consider the relative likelihood of complete global sterilization events from three astrophysical sources – supernovae, gamma-ray bursts, large asteroid impacts, and passing-by stars. To assess such probabilities the researchers consider what cataclysmic event could lead to the annihilation of not just human life, but also extremophiles, through the boiling of all water in Earth’s oceans. Surprisingly, they find that although human life is somewhat fragile to nearby events, the resilience of Ecdysozoa such as Milnesium tardigradum renders global sterilization an unlikely event.

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Extended Periodic Table

Extended Periodic Table | Amazing Science |

An extended periodic table theorizes about elements beyond oganesson (beyond period 7, or row 7). Currently seven periods in the periodic table of chemical elements are known and proven, culminating with atomic number 118, which completes the seventh row. If further elements with higher atomic numbers than this are discovered, they will be placed in additional periods, laid out (as with the existing periods) to illustrate periodically recurring trends in the properties of the elements concerned. Any additional periods are expected to contain a larger number of elements than the seventh period, as they are calculated to have an additional so-called g-block, containing at least 18 elements with partially filled g-orbitals in each period.


An eight-period table containing this block was suggested by Glenn T. Seaborg in 1969.[1][2] IUPAC defines an element to exist if its lifetime is longer than 10−14 seconds, which is the time it takes for the nucleus to form an electron cloud.[3] No elements in this region have been synthesized or discovered in nature.[4] The first element of the g-block may have atomic number 121, and thus would have the systematic name unbiunium. Elements in this region are likely to be highly unstable with respect to radioactive decay, and have extremely short half lives, although element 126 is hypothesized to be within an island of stability that is resistant to fission but not to alpha decay. It is not clear how many elements beyond the expected island of stability are physically possible, whether period 8 is complete, or if there is a period 9.


According to the orbital approximation in quantum mechanical descriptions of atomic structure, the g-block would correspond to elements with partially filled g-orbitals, but spin-orbit coupling effects reduce the validity of the orbital approximation substantially for elements of high atomic number. While Seaborg's version of the extended period had the heavier elements following the pattern set by lighter elements, as it did not take into account relativistic effects; models that take relativistic effects into account do not. Pekka Pyykkö and Burkhard Fricke used computer modeling to calculate the positions of elements up to Z = 172, and found that several were displaced from the Madelung rule.[5][6]


Richard Feynman noted[7] that a simplistic interpretation of the relativistic Dirac equation runs into problems with electron orbitals at Z > 1/α ≈ 137 as described in the sections below, suggesting that neutral atoms cannot exist beyond element 137, and that a periodic table of elements based on electron orbitals therefore breaks down at this point. On the other hand, a more rigorous analysis calculates the limit to be Z ≈ 173.


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Praying Mantises Hunt Down Birds Worldwide

Praying Mantises Hunt Down Birds Worldwide | Amazing Science |
A study by zoologists from Switzerland and the US shows: praying mantises all over the globe also include birds in their diet. The Wilson Journal of Ornithology has just published the results.


Praying mantises are carnivorous insects with powerful raptorial front legs that usually depend on arthropods such as insects or spiders as their primary prey. Rather infrequently, they have also been witnessed eating small vertebrates such as frogs, lizards, salamanders or snakes. A new study by the zoologists Martin Nyffeler (University of Basel), Mike Maxwell (National University, La Jolla, California), and James Van Remsen (Louisiana State University) now shows that praying mantises all over the world also kill and eat small birds.


The researchers gathered and documented numerous examples of bird-eating mantises. In a systematic review, they were able to show that praying mantises from twelve species and nine genera have been observed preying on small birds in the wild. This remarkable feeding behavior has been documented in 13 different countries, on all continents except Antarctica. There is also great diversity in the victims: birds from 24 different species and 14 families were found to be the prey of mantises. "The fact that eating of birds is so widespread in praying mantises, both taxonomically as well as geographically speaking, is a spectacular discovery," comments Martin Nyffeler from the University of Basel and lead author of the study.


The researchers assembled 147 documented cases of this feeding behavior from all over the world. However, more than 70 percent were reported in the US, where praying mantises often capture birds at hummingbird feeders or plants pollinated by hummingbirds in house gardens. Consequently, hummingbirds make up the vast majority of birds killed by praying mantises, with the Ruby-throated Hummingbird (Archilochus colubris) being a particularly frequent victim.


Decades ago, several alien species of large mantises (e.g., Mantis religiosa and Tenodera sinensis) were released across North America as biological pest control agents. These imported species now constitute a new potential threat to hummingbirds and small passerine birds. However, there are also large native mantises that prey on birds. "Our study shows the threat mantises pose to some bird populations. Thus, great caution is advised when releasing mantises for pest control," says Nyffeler.

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Surprise methanol detection in Enceladus’s plumes

Surprise methanol detection in Enceladus’s plumes | Amazing Science |

A serendipitous detection of the organic molecule methanol around an intriguing moon of Saturn suggests that material spewed from Enceladus undertakes a complex chemical journey once vented into space. This is the first time that a molecule from Enceladus has been detected with a ground-based telescope. Dr Emily Drabek-Maunder, of Cardiff University, will present the results on Tuesday 4th July at the National Astronomy Meeting at the University of Hull.


Enceladus's plumes are thought to originate in water escaping from a subsurface ocean through cracks in the moon's icy surface. Eventually these plumes feed into Saturn's second-outermost ring, the E-ring. Drabek-Maunder says: "Recent discoveries that icy moons in our outer Solar System could host oceans of liquid water and ingredients for life have sparked exciting possibilities for their habitability. But in this case, our findings suggest that that methanol is being created by further chemical reactions once the plume is ejected into space, making it unlikely it is an indication for life on Enceladus."


Past studies of Enceladus have involved the NASA/ESA Cassini spacecraft, which has detected molecules like methanol by directly flying into the plumes. Recent work has found similar amounts of methanol in Earth's oceans and Enceladus's plumes.


In this study, Dr Jane Greaves of Cardiff University and Dr Helen Fraser of the Open University detected the bright methanol signature using the IRAM 30-metre radio telescope in the Spanish Sierra Nevada. "This observation was very surprising since it was not the main molecule we were originally looking for in Enceladus's plumes," says Greaves.


The team suggests the unexpectedly large quantity of methanol may have two possible origins: either a cloud of gas expelled from Enceladus has been trapped by Saturn's magnetic field, or gas has spread further out into Saturn's E-ring. In either case, the methanol has been greatly enhanced compared to detections in the plumes. Team member Dr Dave Clements of Imperial College, points out: "Observations aren't always straightforward. To interpret our results, we needed the wealth of information Cassini gave us about Enceladus's environment. This study suggests a degree of caution needs to be taken when reporting on the presence of molecules that could be interpreted as evidence for life."


Cassini will end its journey later this year, leaving remote observations through ground- and space-based telescopes as the only possibility for exploring Saturn and its moons -- at least for now. Drabek-Maunder adds: "This finding shows that detections of molecules at Enceladus are possible using ground-based facilities. However, to understand the complex chemistry in these subsurface oceans, we will need further direct observations by future spacecraft flying through Enceladus's plumes."

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Neutrons detect elusive Higgs amplitude mode in quantum material

Neutrons detect elusive Higgs amplitude mode in quantum material | Amazing Science |

A team led by the Department of Energy's Oak Ridge National Laboratory has used sophisticated neutron scattering techniques to detect an elusive quantum state known as the Higgs amplitude mode in a two-dimensional material.


The Higgs amplitude mode is a condensed matter cousin of the Higgs boson, the storied quantum particle theorized in the 1960s and proven experimentally in 2012. It is one of a number of quirky, collective modes of matter found in materials at the quantum level. By studying these modes, condensed matter researchers have recently uncovered new quantum states known as quasiparticles, including the Higgs mode.


These studies provide unique opportunities to explore quantum physics and apply its exotic effects in advanced technologies such as spin-based electronics, or spintronics, and quantum computing.


"To excite a material's quantum quasiparticles in a way that allows us to observe the Higgs amplitude mode is quite challenging," said Tao Hong, an instrument scientist with ORNL's Quantum Condensed Matter Division. Although the Higgs amplitude mode has been observed in various systems, "the Higgs mode would often become unstable and decay, shortening the opportunity to characterize it before losing sight of it," Hong said.


The ORNL-led team offered an alternative method. The researchers selected a crystal composed of copper bromide, because the copper ion is ideal for studying exotic quantum effects, Hong explained. They began the delicate task of "freezing" the material's agitating quantum-level particles by lowering its temperature to 1.4 Kelvin, which is about minus 457.15 degrees Fahrenheit.


The researchers fine-tuned the experiment until the particles reached the phase located near the desired quantum critical point -- the sweet spot where collective quantum effects spread across wide distances in the material, which creates the best conditions to observe a Higgs amplitude mode without decay.


With neutron scattering performed at ORNL's High Flux Isotope Reactor, the research team observed the Higgs mode with an infinite lifetime: no decay. "There's an ongoing debate in physics about the stability of these very delicate Higgs modes," said Alan Tennant, chief scientist of ORNL's Neutron Sciences Directorate. "This experiment is really hard to do, especially in a two-dimensional system. And, yet, here's a clear observation, and it's stabilized."

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Milky Way could harbor 100 billion brown dwarfs

Milky Way could harbor 100 billion brown dwarfs | Amazing Science |

Our galaxy could have 100 billion brown dwarfs or more, according to work by an international team of astronomers, led by Koraljka Muzic from the University of Lisbon and Aleks Scholz from the University of St Andrews. On Thursday 6 July Scholz will present their survey of dense star clusters, where brown dwarfs are abundant, at the National Astronomy Meeting at the University of Hull.


Brown dwarfs are objects intermediate in mass between stars and planets, with masses too low to sustain stable hydrogen fusion in their core, the hallmark of stars like the Sun. After the initial discovery of brown dwarfs in 1995, scientists quickly realised that they are a natural by-product of processes that primarily lead to the formation of stars and planets.


All of the thousands of brown dwarfs found so far are relatively close to the Sun, the overwhelming majority within 1500 light years, simply because these objects are faint and therefore difficult to observe. Most of those detected are located in nearby star forming regions, which are all fairly small and have a low density of stars.


In 2006 the team began a new search for brown dwarfs, observing five nearby star forming regions. The Substellar Objects in Nearby Young Clusters (SONYC) survey included the star cluster NGC 1333, 1000 light years away in the constellation of Perseus. That object had about half as many brown dwarfs as stars, a higher proportion than seen before.


To establish whether NGC 1333 was unusual, in 2016 the team turned to another more distant star cluster,RCW 38, in the constellation of Vela. This has a high density of more massive stars, and very different conditions to other clusters.


RCW 38 is 5500 light years away, meaning that the brown dwarfs are both faint, and hard to pick out next to the brighter stars. To get a clear image, Scholz, Muzic and their collaborators used the NACO adaptive optics camera on the European Southern Observatory's Very Large Telescope, observing the cluster for a total of almost 3 hours, and combining this with earlier work.


The researchers found just as many brown dwarfs in RCW 38 – about half as many as there are stars- and realised that the environment where the stars form, whether stars are more or less massive, tightly packed or less crowded, has only a small effect on how brown dwarfs form.


Scholz says: "We've found a lot of brown dwarfs in these clusters. And whatever the cluster type, the brown dwarfs are really common. Brown dwarfs form alongside stars in clusters, so our work suggests there are a huge number of brown dwarfs out there."


From the SONYC survey, Scholz and team leader Koraljka Muzic, estimate that our galaxy, the Milky Way, has a minimum of between 25 and 100 billion brown dwarfs. There are many smaller, fainter brown dwarfs too, so this could be a significant underestimate, and the survey confirms these dim objects are ubiquitous.

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Germans provide big boost for sequencing often ignored organisms

Germans provide big boost for sequencing often ignored organisms | Amazing Science |

One of Germany’s states has provided a big boost for biologists who want to decipher the genomes of organisms that don’t get much attention. This week, the state of Hessen, which includes Frankfurt, awarded its local institutions €17.6 million, the first half of a 7-year grant for sequencing plants, animals, and fungi. The award includes funding for the high-quality sequencing of about 700 organisms, and for the partial sequencing or resequencing of thousands more.


“German scientists are going to take a big step forward in understanding the genomic basis of life,” says W. John Kress, a researcher at the Smithsonian Institution in Washington, D.C., who helped conceive the Earth BioGenome Project, an ambitious effort to sequence much of life on Earth.


The grant will create the new LOEWE-Zentrum für Translationale Biodiversitätsgenomik (LOEWE-TBG)—loosely translated as the Translational Biodiversity Genomics Excellence Center. It is the brainchild of Axel Janke, Markus Pfenninger, and Steffen Pauls, genomics researchers at the Senckenberg Research Institute and Natural History Museum in Frankfurt. The center, scheduled to open in January 2018, will involve the museum, Goethe University Frankfurt, the Justus Liebig University Giessen, and the Fraunhofer Institute for Molecular Biology and Applied Ecology.  

Via Integrated DNA Technologies
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From dry to wet: Rainfall might abruptly increase in Africa’s Sahel zone

From dry to wet: Rainfall might abruptly increase in Africa’s Sahel zone | Amazing Science |
Climate change could turn one of Africa's driest regions into a very wet one by suddenly switching on a Monsoon circulation. For the first time, scientists find evidence in computer simulations for a possible abrupt change to heavy seasonal rainfall in the Sahel, a region that so far has been characterized by extreme dryness. They detect a self-amplifying mechanism which might kick-in beyond 1.5-2 degrees Celsius of global warming – which happens to be the limit for global temperature rise set in the Paris Climate Agreement. Although crossing this new tipping point is potentially beneficial, the change could be so big, it would be a major adaptation challenge for an already troubled region. Further warming might enhance water availability for farming and grazing.

“More rain in a dry region can be good news,” says lead-author Jacob Schewe from the Potsdam Institute for Climate Impact Research (PIK). “Climate change due to greenhouse gases from burning fossil fuels really has the power to shake things up. It is driving risks for crop yields in many regions and generally increases dangerous weather extremes around the globe, yet in the dry Sahel there seems to be a chance that further warming might indeed enhance water availability for farming and grazing.”


Co-author Anders Levermann from PIK and Columbia University’s Lamont-Doherty Earth Observatory adds: “We don’t know what the impacts on the ground will be, this is beyond the scope of our study; but imagine the chance of a greening Sahel. Still, the sheer size of the possible change is mindboggling – this is one of the very few elements in the Earth system that we might witness tipping soon. Once the temperature approaches the threshold, the rainfall regime could shift within just a few years.”

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Scientists recreate an extinct virus, a relative of smallpox

Scientists recreate an extinct virus, a relative of smallpox | Amazing Science |

Scientists at the University of Alberta have put together – from scratch – a relative of the smallpox virus, which serves as a reminder that the threat of deadly viruses created by humans is more than just theoretical.

The smallpox virus, which triggered brutal disease for centuries, was declared eradicated in 1980 after a successful global effort to end its reign of terror. But some scientists fear that it could be revived through what’s known as synthetic biology — the ability to make a virus by putting together by the recipe outlined in its genetic code.

The horsepox virus the Canadian team created is not a threat to human health — or even the health of horses — should it ever escape from a lab. And it’s not the first virus created by putting pieces of DNA together in the right sequence.

Still, the news that a team headed by David Evans, a professor of medical microbiology and immunology, had accomplished this feat — at a relatively low cost of about $100,000 plus labor — was a bit of a wakeup call. The news was first reported Thursday in Science Magazine.

“This is an example of what modern technologies can do,” noted Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

The warnings about the implications of synthetic biology have echoed since Eckard Wimmer of the State University of New York at Stony Brook reported in 2002 that he and his team had made a poliovirus from scratch.

Polioviruses are small in comparison with poxviruses, and a far less complex task. But scientists watching this field feared it was only a matter of time before the obstacles to creating other viruses were surmounted.

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