Amazing Science
769.9K views | +188 today
Amazing Science
Amazing science facts - 3D_printing • aging • AI • anthropology • art • astronomy • bigdata • bioinformatics • biology • biotech • chemistry • computers • cosmology • education • environment • evolution • future • genetics • genomics • geosciences • green_energy • history • language • map • material_science • math • med • medicine • microscopy • nanotech • neuroscience • paleontology • photography • photonics • physics • postings • robotics • science • technology • video
Your new post is loading...
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Fixing a Million-Year Clock by Settling the Half-Life of Iron-60 for a Versatile Astrophysical Chronometer

Fixing a Million-Year Clock by Settling the Half-Life of Iron-60 for a Versatile Astrophysical Chronometer | Amazing Science | Scoop.it

Radioactive iron-60 (60Fe) is produced at the core of large stars and in supernovae, and it has a half-life of roughly a million years, so its abundance can be used to date astrophysical events on a similar time scale. Scientists have, for example, used the small amount of 60Fe deposited in deep-sea crust to trace the history of supernovae near our Solar System, which may have affected Earth’s climate in the past. But the best measures of 60Fe’s half-life—one performed in 1984, the other in 2009—disagree by nearly a factor of 2. Now, a new experiment settles the discrepancy, enabling more astrophysical studies based on the isotope, such as the monitoring of nucleosynthesis in stars.


To derive the half-life of a long-lived isotope, scientists use samples containing a known number of the nuclei and detect how many of them decay per second. In the case of 60Fe, its decays are monitored by detecting the gamma rays emitted by its daughter nucleus, cobalt-60. But the main uncertainty in earlier experiments has been the initial number of decaying 60Fe nuclei. Working with an iron sample extracted from irradiated copper, Anton Wallner, at the Australian National University, and his colleagues used accelerator mass spectrometry to determine the small concentration of 60Fe isotopes. By comparing this number to the concentration of 55Fe, another rare isotope, they were able to “cancel out” some of the systematic errors that plagued earlier experiments and accurately gauge the 60Fe amount. The half-life they find agrees well with the 2009 value; averaging the two together, Wallner et al. report a value of 2.60 million years and a 2% uncertainty.


This research is published in Physical Review Letters.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Scientists find hydrogen production in an extremophile bacterium (Halanaerobium hydrogeninformans)

Scientists find hydrogen production in an extremophile bacterium (Halanaerobium hydrogeninformans) | Amazing Science | Scoop.it

Dr. Melanie Mormile, professor of biological sciences at Missouri S&T, and her team discovered the bacterium "Halanaerobium hydrogeninformans" in Soap Lake, Washington. It can "produce hydrogen under saline and alkaline conditions in amounts that rival genetically modified organisms," Mormile says.


"Usually, I tend to study the overall microbial ecology of extreme environments, but this particular bacterium has caught my attention," Mormile says. "I intend to study this isolate in greater detail."


Mormile, an expert in the microbial ecology of extreme environments, wasn't searching for a bacterium that could produce hydrogen. Instead, she first became interested in bacteria that could help clean up the environment, especially looking at the extremophiles found in Soap Lake.


An extremophile is a microorganism that lives in conditions of extreme temperature, acidity, alkalinity or chemical concentration. Living in such a hostile environment, "Halanaerobium hydrogeninformans" has metabolic capabilities under conditions that occur at some contaminated waste sites.


With "Halanaerobium hydrogeninformans," she expected to find an iron-reducing bacterium and describe a new species. What she found was a new species of bacterium that can produce hydrogen and 1, 3-propanediol under high pH and salinity conditions that might turn out to be valuable industrially. An organic compound, 1, 3-propenediol can be formulated into industrial products including composites, adhesives, laminates and coatings. It's also a solvent and can be used as antifreeze.


The infrastructure isn't in place now for hydrogen to replace gasoline as a fuel for planes, trains and automobiles. But if hydrogen becomes an alternative to gasoline, "Halanaerobium hydrogeniformans," mass-produced on an industrial scale, might be one solution – although it won't be a solution anytime soon.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Viruses In Our Genome: Forty Million Years In the Making

Viruses In Our Genome: Forty Million Years In the Making | Amazing Science | Scoop.it

Each year, billions of people get infected with viruses–with common ones like influenza and cold viruses, and rarer ones like polio and Ebola. The viruses don’t stay all that long inside of us. In most cases, our immune systems wipe them out, except for a few refugees that manage to escape to a new host and keep their species alive. In some cases, the viruses kill their unfortunate hosts, and end their own existence as well. But in some exquisitely rare cases, viruses meld with the genome of their hosts and become part of the genetic legacy their hosts pass down to future generations.


Scientists know this melding has happened because viruses have distinctive genes. When scientists scan the human genome, they sometimes come across a stretch of DNA that bears the hallmarks of viruses. The easiest type of virus to recognize are retroviruses, a group that includes HIV. Retroviruses make copies of themselves by infecting cells and then using an enzyme to insert their genes into their host cell’s DNA. The cell then reads the inserted DNA and makes new molecules that assemble into new viruses.


Humans carry about 100,000 pieces of DNA that came from retroviruses–known as endogenous retroviruses. All told, they come to an estimated 5 to 8 percent of the entire human genome. That’s several times more DNA that makes up all 20,000 of our protein-coding genes.


Gkikas Magiorkinis, a University of Oxford virologist, and his colleagues have now carried out large-scale survey of endogenous retroviruses in humans, apes, and Old World monkeys–a group of species that all descend from a common primate ancestor that lived some 40 million years ago. They catalogued the viruses in each species and compared them to the versions in the other primates. They were able to reconstruct the history of our viral DNA in unprecedented detail, even coming up with estimates for the rate at which the viruses inserted new copies into our genome.


The scientists can trace our viral DNA to 30 to 35 separate invasions. Once each virus established itself in our ancestors’ DNA, it produced copies of itself scattered through the genome. The rate at which new copies were inserted rose and fell over time, and at different rates in different branches of the primate tree. Here’s an overall look at the history of the viruses. 


Our monkey-like ancestors 40 million years ago acquired new virus copies at a fast clip–much faster than in our own lineage in the past couple million years. One virus in particular, known as HERV-H, was responsible for most of the new copies. It may have evolved adaptations that made it into a superspreader inside the genome.


In the past million years, only a single virus has continued to multiply–known as HERV-K. Today, you can find some HERV-K copies in some people and not in others. The pattern of these copies suggests that as recently as 250,000 years ago, HERV-K was still making new copies.


It’s possible that HERV-K is completely dead now. There’s no evidence that HERV-K or any other endogenous retrovirus is actively spreading or causing cancer. It’s hard to say at this point why humans have put the brakes on endogenous retroviruses. But Magiorkinis has one suggestion: our ancestors may have reduced their odds of picking up new viruses.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Technique greatly extends duration of fragile quantum states, pointing toward practical quantum computers

Technique greatly extends duration of fragile quantum states, pointing toward practical quantum computers | Amazing Science | Scoop.it

Quantum computers are experimental devices that promise exponential speedups on some computational problems. Where a bit in a classical computer can represent either a 0 or a 1, a quantum bit, or qubit, can represent 0 and 1 simultaneously, letting quantum computers explore multiple problem solutions in parallel. But such “superpositions” of quantum states are, in practice, difficult to maintain.


In a paper appearing this week in Nature Communications, MIT researchers and colleagues at Brookhaven National Laboratory and the synthetic-diamond company Element Six describe a new design that in experiments extended the superposition time of a promising type of qubit a hundredfold.


In the long term, the work could lead toward practical quantum computers. But in the shorter term, it could enable the indefinite extension of quantum-secured communication links, a commercial application of quantum information technology that currently has a range of less than 100 miles.


The researchers’ qubit design employs nitrogen atoms embedded in synthetic diamond. When nitrogen atoms happen to be situated next to gaps in the diamond’s crystal lattice, they produce “nitrogen vacancies,” which enable researchers to optically control the magnetic orientation, or “spin,” of individual electrons and atomic nuclei. Spin can be up, down, or a superposition of the two.


To date, the most successful demonstrations of quantum computing have involved atoms trapped in magnetic fields. But “holding an atom in vacuum is difficult, so there’s been a big effort to try to trap them in solids,” says Dirk Englund, the Jamieson Career Development Assistant Professor in Electrical Engineering and Computer Science at MIT and corresponding author on the new paper.


“In particular, you want a transparent solid, so you can send light in and out. Crystals are better than many other solids, like glass, in that their atoms are nice and regular and their electronic structure is well defined. And amongst all the crystals, diamond is a particularly good host for capturing an atom, because it turns out that the nuclei of diamond are mostly free of magnetic dipoles, which can cause noise on the electron spin.”

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Infants create new knowledge while sleeping

Infants create new knowledge while sleeping | Amazing Science | Scoop.it

There is no rest for a baby's brain – not even in sleep. While infants sleep they are reprocessing what they have learned. Working with researchers from the University of Tübingen, scientists from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig have discovered that babies of the age from 9 to 16 months remember the names of objects better if they had a short nap. And only after sleeping can they transfer learned names to similar new objects. The infant brain thus forms general categories during sleep, converting experience into knowledge. The researchers also showed that the formation of categories is closely related to a typical rhythmic activity of the sleeping brain called sleep spindles: Infants with high sleep spindle activity are particularly good at generalizing their experiences and developing new knowledge while sleeping.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Human male gives birth to two dipterian children

Human male gives birth to two dipterian children | Amazing Science | Scoop.it

Entomologists are not like other people. Lucky enough to score a cool parasitic larva burrowing in your skin after a visit to Central America? The obvious thing to do is to rear your maggot out in your body until it’s an adult fly. For science.


In the last week, two entomologists proudly issued bot fly “birth” announcements of their little monsters. For one of them, it was his second try at rearing out the flesh-eating maggots to adults. His first unsuccessful attempt at bot fly rearing in 2013 did result in a research publication, though, so it wasn’t a wasted effort.


Piotr Nasrecki documented the entire process of his bot fly maggot rearing in a fascinating video. Yes, there is some blood. But you’ll also learn a lot about flies - and entomologists.


Below are excerpts from both scientists’ accounts of their maggoty pregnancies; I highly recommend reading both. Both Naskrecki and Wizen have written great explanations of the bot fly life cycle, with beautiful photos.


“Raising two dipteran [fly] children was an interesting experience. It was embarrassing on a few occasions, when both of my arms started bleeding profusely in public; painful at times, to the point of waking me up in the middle of the night; and inconvenient during the last stages of the flies’ development, when I had to tape plastic containers to my arms to make sure that I will not lose the emerging larvae. But other than those minor discomforts it was really not a big deal. Perhaps my opinion would have been different had the bot flies decided to develop in my eyelids, but I actually grew to like my little guests, and watched their growth with the same mix of pleasure and apprehension as when I watch the development of any other interesting organism under my care.”

Piotr Naskrecki


Sitting at my dentist chair for 40 minutes and suffering through the shrill sound of the ultrasonic cleaner, I suddenly started to feel contractions from my chest. Oh, no. Not now. Is it really happening? If it happens now this will be a visit I will never forget. Am I getting into labor?… In the end, the contractions I felt at the dentist were a false alarm, and I could not feel anything when the larva eventually emerged.
Gil Wizen


more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Self-propelled subatomic particles accelerate without a push, extending lifetime of unstable isotopes

Self-propelled subatomic particles accelerate without a push, extending lifetime of unstable isotopes | Amazing Science | Scoop.it

Some physical principles have been considered immutable since the time of Isaac Newton: Light always travels in straight lines. No physical object can change its speed unless some outside force acts on it.


Not so fast, says a new generation of physicists: While the underlying physical laws haven’t changed, new ways of “tricking” those laws to permit seemingly impossible actions have begun to appear. For example, work that began in 2007 proved that under special conditions, light could be made to move along a curved trajectory — a finding that is already beginning to find some practical applications.


Now, in a new variation on the methods used to bend light, physicists at MIT and Israel’s Technion have found that subatomic particles can be induced to speed up all by themselves, almost to the speed of light, without the application of any external forces. The same underlying principle could also be used to extend the lifetime of some unstable isotopes, perhaps opening up new avenues of research in basic particle physics.


The findings, based on a theoretical analysis, were published in the journal Nature Physics by MIT postdoc Ido Kaminer and four colleagues at the Technion. The new findings are based on a novel set of solutions for a set of basic quantum-physics principles called the Dirac equations; these describe the relativistic behavior of fundamental particles, such as electrons, in terms of a wave structure. (In quantum mechanics, waves and particles are considered to be two aspects of the same physical phenomena). By manipulating the wave structure, the team found, it should be possible to cause electrons to behave in unusual and counterintuitive ways.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Stomach-acid-powered micromotors first-time tested in living animal

Stomach-acid-powered micromotors first-time tested in living animal | Amazing Science | Scoop.it

Imagine a micromotor fueled by stomach acid that can take a bubble-powered ride inside a mouse — and that could one day be a safer, more efficient way to deliver drugs or diagnose tumors for humans.

That’s the goal of a team of researchers at the University of California, San Diego. The experiment is the first to show that these micromotors can operate safely in a living animal, said Professors Joseph Wang and Liangfang Zhang of the NanoEngineering Department at the UC San Diego Jacobs School of Engineering.


Wang, Zhang and others have experimented with different designs and fuel systems for micromotors that can travel in water, blood and other body fluids in the lab. “But this is the first example of loading and releasing a cargo in vivo,” said Wang. “We thought it was the logical extension of the work we have done, to see if these motors might be able to swim in stomach acid.”


In the experiment, the mice ingested tiny drops of solution containing hundreds of the micromotors, which are 20 micrometers long. The motors become active as soon as they hit the stomach acid and zoom toward the stomach lining at a speed of 60 micrometers per second. They can self-propel like this for up to 10 minutes. This propulsive burst improved how well the cone-shaped motors were able to penetrate and stick in the mucous layer covering the stomach wall, explained Zhang. “It’s the motor that can punch into this viscous layer and stay there, which is an advantage over more passive delivery systems,” he said.


The researchers found that nearly four times as many zinc micromotors found their way into the stomach lining compared with platinum-based micromotors, which don’t react with and can’t be fueled by stomach acid.


The researchers explain that stomach acid reacts with the zinc body of the motors to generate a stream of hydrogen microbubbles that propel the motors forward. In their open-access study published in the journal ACS Nano, the researchers report that the motors lodged themselves firmly in the stomach lining of mice. As the zinc motors are dissolved by the acid, they disappear within a few days leaving no toxic chemical traces.


Wang said it may be possible to add navigation capabilities and other functions to the motors, to increase their targeting potential. Now that his team has demonstrated that the motors work in living animals, he noted, similar nanomachines soon may find a variety of applications including drug delivery, diagnostics, nanosurgery and biopsies of hard-to-reach tumors.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

55,000-Year-Old Skull Fragment May Be Linked to 1st Europeans

55,000-Year-Old Skull Fragment May Be Linked to 1st Europeans | Amazing Science | Scoop.it

An ancient human skull fragment found in Israel may come from a close relative of the first modern humans to colonize Europe, researchers say.

The finding sheds light on the migration of modern humans out of Africa, and could provide insights into when modern humans first interbred with Neanderthals, scientists added.


Modern humans first arose between 150,000 and 200,000 years ago in Africa. Scientists have suggested the African exodus of modern humans started between 60,000 and 70,000 years ago, but much remains a mystery about this dispersal because of the scarcity of human fossils from this time.


Now, researchers have discovered a 55,000-year-old partial skull in Israel, from about the time when modern humans expanded out of Africa. The investigators say the anatomy of this fossil may offer clues about what the first modern human Europeans were like.


The fossil was discovered accidentally in 2008, when a bulldozer unearthed a cave during a construction project at the modern settlement of Manot, in northern Israel. The original entrance to the cave was sealed off by a rockfall about 30,000 years ago, making it a relatively pristine time capsule, according to co-lead study author Ofer Marder, an archaeologist at Ben-Gurion University of the Negev in Israel.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Science pours in from the Rosetta comet mission

Science pours in from the Rosetta comet mission | Amazing Science | Scoop.it

The first major haul of research from the European Space Agency’s Rosetta mission, published in seven papers1–7 in Science on 22 January, reveals a rich and diverse landscape on 67P/Churyumov–Gerasimenko, the most studied comet in history.  The visible and infrared portrait of 67P’s surface, obtained by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS), shows an abundance of opaque, organic compounds, but very little water ice. This would be consistent with an origin for the comet in the distant Kuiper belt — beyond the orbit of Neptune — rather than closer to Jupiter, as its current orbit would suggest4.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

NASA, Microsoft Collaboration Will Allow Scientists to 'Work on Mars'

NASA, Microsoft Collaboration Will Allow Scientists to 'Work on Mars' | Amazing Science | Scoop.it
NASA and Microsoft have teamed up to develop software called OnSight, a new technology that will enable scientists to work virtually on Mars using wearable technology called Microsoft HoloLens.

Developed by NASA's Jet Propulsion Laboratory in Pasadena, California, OnSight will give scientists a means to plan and, along with the Mars Curiosity rover, conduct science operations on the Red Planet.

"OnSight gives our rover scientists the ability to walk around and explore Mars right from their offices," said Dave Lavery, program executive for the Mars Science Laboratory mission at NASA Headquarters in Washington. "It fundamentally changes our perception of Mars, and how we understand the Mars environment surrounding the rover."

OnSight will use real rover data and extend the Curiosity mission's existing planning tools by creating a 3-D simulation of the Martian environment where scientists around the world can meet. Program scientists will be able to examine the rover's worksite from a first-person perspective, plan new activities and preview the results of their work firsthand.

"We believe OnSight will enhance the ways in which we explore Mars and share that journey of exploration with the world," said Jeff Norris, JPL's OnSight project manager.

Until now, rover operations required scientists to examine Mars imagery on a computer screen, and make inferences about what they are seeing. But images, even 3-D stereo views, lack a natural sense of depth that human vision employs to understand spatial relationships.

The OnSight system uses holographic computing to overlay visual information and rover data into the user's field of view. Holographic computing blends a view of the physical world with computer-generated imagery to create a hybrid of real and virtual.

To view this holographic realm, members of the Curiosity mission team don a Microsoft HoloLens device, which surrounds them with images from the rover's Martian field site. They then can stroll around the rocky surface or crouch down to examine rocky outcrops from different angles. The tool provides access to scientists and engineers looking to interact with Mars in a more natural, human way.

"Previously, our Mars explorers have been stuck on one side of a computer screen. This tool gives them the ability to explore the rover's surroundings much as an Earth geologist would do field work here on our planet," said Norris.
more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Gigantic ring system around exoplanet J1407b found – much larger and heavier than Saturn's

Gigantic ring system around exoplanet J1407b found – much larger and heavier than Saturn's | Amazing Science | Scoop.it

VIDEO presentation


Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn. The ring system - the first of its kind to be found outside our solar system - was discovered in 2012 by a team led by Rochester's Eric Mamajek.


A new analysis of the data, led by Leiden's Matthew Kenworthy, shows that the ring system consists of over 30 rings, each of them tens of millions of kilometers in diameter. Furthermore, they found gaps in the rings, which indicate that satellites ("exomoons") may have formed. The result has been accepted for publication in the Astrophysical Journal.


"The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings," says Kenworthy. "The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn's rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon."


"This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn's rings are today," said co-author Mamajek, professor of physics and astronomy at the University of Rochester. "You could think of it as kind of a super Saturn."


The astronomers analyzed data from the SuperWASP project - a survey that is designed to detect gas giants that move in front of their parent star. In 2012, Mamajek and colleagues at the University of Rochester reported the discovery of the young star J1407 and the unusual eclipses, and proposed that they were caused by a moon-forming disk around a young giant planet or brown dwarf.


In a third, more recent study also led by Kenworthy, adaptive optics and Doppler spectroscopy were used to estimate the mass of the ringed object. Their conclusions based on these and previous papers on the intriguing system J1407 is that the companion is likely to be a giant planet - not yet seen - with a gigantic ring system responsible for the repeated dimming of J1407's light.


The light curve tells astronomers that the diameter of the ring system is nearly 120 million kilometers, more than two hundred times as large as the rings of Saturn. The ring system likely contains roughly an Earth's worth of mass in light-obscuring dust particles.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Exotic, gigantic molecules - predicted since 1970 - fit inside each other like Russian nesting dolls

Exotic, gigantic molecules - predicted since 1970 - fit inside each other like Russian nesting dolls | Amazing Science | Scoop.it

University of Chicago scientists have experimentally observed for the first time a phenomenon in ultracold, three-atom molecules predicted by Russian theoretical physicist Vitaly Efimov in 1970.


In this quantum phenomenon, called geometric scaling, the triatomic molecules fit inside one another like an infinitely large set of Russian nesting dolls. “This is a new rule in chemistry that molecular sizes can follow a geometric series, like 1, 2, 4, 8…,” said Cheng Chin, professor in physics. “In our case, we find three molecular states in this sequence where one molecular state is about 5 times larger than the previous one.”

Chin and four members of his research group published their findings Dec. 9, 2014, in Physical Review Letters.


“Quantum theory makes the existence of these gigantic molecules inevitiable, provided proper—and quite challenging—conditions are created,” said Efimov, now at the University of Washington. The UChicago team observed three molecules in the series, consisting of one lithium atom and two cesium atoms in a vacuum chamber at the ultracold temperature of approximately 200 nanokelvin, a tiny fraction of a degree above absolute zero (minus 459.6 degrees Fahrenheit).


Given an infinitely large universe, the number of increasingly larger molecules in this cesium-lithium system also would extend to infinity. This remarkable idea stems from the exotic nature of quantum mechanics, which conforms to different laws of physics than those that govern the universe on a macroscopic scale.


“These are certainly exotic molecules,” said Shih-Kuang Tung, the postdoctoral scholar, now at Northwestern University, who led the project. Only under strict conditions could Tung and his colleagues see the geometric scaling in their Efimov molecules. It appears that neither two-atom nor four-atom molecules can achieve the Efimov state. “There’s a special case for three atoms,” Chin said.


Efimov’s reaction to the research was twofold: “First, I am amazed by the predictive power of the quantum theory,” he said. “Second, I am amazed by the skill of the experimentalists who managed to create those challenging conditions.”

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Clonal Expansion of Early to Mid-Life Mitochondrial DNA Mutations Drives Mitochondrial Dysfunction during Human Aging

Clonal Expansion of Early to Mid-Life Mitochondrial DNA Mutations Drives Mitochondrial Dysfunction during Human Aging | Amazing Science | Scoop.it

Age-related decline in the integrity of mitochondria is an important contributor to the human aging process. In a number of ageing stem cell populations, this decline in mitochondrial function is due to clonal expansion of individual mitochondrial DNA (mtDNA) point mutations within single cells. However the dynamics of this process and when these mtDNA mutations occur initially are poorly understood. Using human colorectal epithelium as an exemplar tissue with a well-defined stem cell population, researchers have now analyzed samples from 207 healthy participants aged 17–78 years using a combination of techniques (Random Mutation Capture, Next Generation Sequencing and mitochondrial enzyme histochemistry), and show that: 1) non-pathogenic mtDNA mutations are present from early embryogenesis or may be transmitted through the germline, whereas pathogenic mtDNA mutations are detected in the somatic cells, providing evidence for purifying selection in humans, 2) pathogenic mtDNA mutations are present from early adulthood (<20 years of age), at both low levels and as clonal expansions, 3) low level mtDNA mutation frequency does not change significantly with age, suggesting that mtDNA mutation rate does not increase significantly with age, and 4) clonally expanded mtDNA mutations increase dramatically with age. These data confirm that clonal expansion of mtDNA mutations, some of which are generated very early in life, is the major driving force behind the mitochondrial dysfunction associated with ageing of the human colorectal epithelium.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Energy-Harvesting Piezoelectric Flags

Energy-Harvesting Piezoelectric Flags | Amazing Science | Scoop.it

The movement of a flag made of piezoelectric elements could be used to convert the wind’s mechanical energy into electrical power. In a steady wind flow, instabilities arising from the flag-wind interaction can lead to self-sustained flapping, which generates current in a coupled output circuit, as shown by a number of recent studies. However, the design of an optimal circuit remains a challenge: The circuit can induce a feedback coupling to the piezoelectric material, which, under some conditions, hinders flapping and lowers device efficiency. Yifan Xia, from École Polytechnique, France, and colleagues have now calculated that with an optimized resonant circuit, stable flapping motion, robust to velocity fluctuations, can be achieved at lower flow velocities than in previous studies. The scheme could open the way to efficient piezoelectric technologies that can harvest energy from a wide range of fluids (wind, tides, rivers, etc.)

The authors modeled a simple plane flag covered on both surfaces with piezoelectric patches and connected to a resonant circuit containing inductive and resistive elements. They found that when the flapping frequency was close to the natural frequency of the circuit, the two frequencies locked-in and the whole system resonated. By proper choice of the circuit’s frequency, the amplitude of the flapping and the energy output could be maximized. The frequency lock-in had two other advantages. First, it made flapping and energy harvest more robust: Small fluid velocity fluctuations, which could have shifted the flapping frequency, making it unstable, had little effect. Second, flapping could be induced at lower fluid velocities, at which the flag otherwise would not have flapped, extending the wind-velocity range suitable for energy harvesting.

This research is published in Physical Review Applied.

more...
Laurent RUEL - HGAD Consulting's curator insight, February 25, 2015 5:25 AM

extra power for free for all static consuming units in telecom, ...

Scooped by Dr. Stefan Gruenwald
Scoop.it!

Researchers show a machine learning network for connected devices

Researchers show a machine learning network for connected devices | Amazing Science | Scoop.it

Researchers at Ohio State University have developed a method for building a machine learning algorithm from data gathered from a variety of connected devices. There are two cool things about their model worth noting. The first is that the model is distributed and second, it can keep data private.


The researchers call their model Crowd-ML and the idea is pretty basic. Each device runs a version of a necessary app, much like one might run a version of SETI@home or other distributed computing application, and grabs samples of data to send to a central server. The server can tell when enough of the right data has been gathered to “teach” the computer and only grabs the data it needs, ensuring a relative amount of privacy.


The model uses a variant of stochastic (sub)gradient descent instead of batch processing, to grab data for machine learning, which is what makes the Crowd-ML effort different. Stochastic gradient descent is the basis for a lot of machine learning and deep learning efforts. It uses knowledge gleaned from previous computations to inform the next computations, making it iterative, as opposed to something processed all at once.


The paper goes on to describe how one can tweak the Crowd-ML model to ensure more or less privacy and process information faster or in greater amounts. It tries to achieve the happy medium between protecting privacy and gathering the right amount of data to generate a decent sample size to train the machine learning algorithm.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Mastering multicore: Parallelizing common algorithms

Mastering multicore: Parallelizing common algorithms | Amazing Science | Scoop.it

Every undergraduate computer-science major takes a course on data structures, which describes different ways of organizing data in a computer’s memory. Every data structure has its own advantages: Some are good for fast retrieval, some for efficient search, some for quick insertions and deletions, and so on.


Today, hardware manufacturers are making computer chips faster by giving them more cores, or processing units. But while some data structures are well adapted to multicore computing, others are not. In principle, doubling the number of cores should double the efficiency of a computation. With algorithms that use a common data structure called a priority queue, that’s been true for up to about eight cores — but adding any more cores actually causes performance to plummet.


At the Association for Computing Machinery’s Symposium on Principles and Practice of Parallel Programming in February, researchers from MIT’s Computer Science and Artificial Intelligence Laboratory will describe a new way of implementing priority queues that lets them keep pace with the addition of new cores. In simulations, algorithms using their data structure continued to demonstrate performance improvement with the addition of new cores, up to a total of 80 cores.


A priority queue is a data structure that, as its name might suggest, sequences data items according to priorities assigned them when they’re stored. At any given time, only the item at the front of the queue — the highest-priority item — can be retrieved. Priority queues are central to the standard algorithms for finding the shortest path across a network and for simulating events, and they’ve been used for a host of other applications, from data compression to network scheduling.


With multicore systems, however, conflicts arise when multiple cores try to access the front of a priority queue at the same time. The problem is compounded by modern chips’ reliance on caches — high-speed memory banks where cores store local copies of frequently used data.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Almost half of the processes crucial to maintaining the stability of the planet are dangerously compromised

Almost half of the processes crucial to maintaining the stability of the planet are dangerously compromised | Amazing Science | Scoop.it

An international team of 18 researchers provide new evidence of significant changes in four of the nine systems which regulate the resilience of the Earth. One of the systems which has been seriously affected is the nitrogen-phosphorus cycle which is essential to all life, and is particularly important to both food production and the maintenance of clean water.


"People depend on food, and food production depends on clean water," says Prof. Elena Bennett from McGill's School of the Environment who contributed the research on the nitrogen-phosphorus cycle to the study. "This new data shows that our ability both to produce sufficient food in the future and to have clean water to drink and to swim in are at risk."


The research fixing new planetary boundaries (which represent thresholds or tipping points beyond which there will be irreversible and abrupt environmental change) was published today in the journal Science. It suggests that changes to the Earth's climate, biosphere integrity (a concept covering loss of biodiversity and species extinction), and land-system (through deforestation for example) represent a risk for current and future societies. The fourth process which has become significantly compromised is the nitrogen-phosphorus cycle, which affects both the water we drink and our ability to produce food.


Key points:

  • The concept of planetary boundaries has been updated with new assessments and quantifications.
  • Climate change and biosphere integrity identified as core planetary boundaries. Significantly altering either of these "core boundaries" would "drive the Earth System into a new state".
  • Four boundaries are assessed to have been crossed, placing humanity in a danger zone: climate change, loss of biosphere integrity (biodiversity loss and species extinction), land-system change, altered biogeochemical cycles (fertiliser use - phosphorus and nitrogen).
  • Crossing boundaries raises the risks to current and future societies of destabilising the Earth System – the complex interactions of land, ocean, atmosphere, ice sheets, life and people.
  • Internationally agreed upper climate limit of 2 degrees lies beyond the climate change boundary: which makes 2 degrees a risky target for humanity, and therefore an absolute minimum target for the global climate negotiations.


Nine planetary boundaries:

  • Climate change
  • Change in biosphere integrity (biodiversity loss and species extinction)
  • Stratospheric ozone depletion
  • Ocean acidification
  • Biogeochemical flows (phosphorus and nitrogen cycles)
  • Land-system change (for example deforestation)
  • Freshwater use
  • Atmospheric aerosol loading (microscopic particles in the atmosphere that affect climate and living organisms)
  • Introduction of novel entities (e.g. organic pollutants, radioactive materials, nanomaterials, and micro-plastics).
more...
Charlie Dare's curator insight, January 31, 2015 6:59 AM

Unfortunately countries like India and China are hell bent on so called progress spewing more CO2 in the atmosphere in greater amounts.The Chinese are going to create rain by weather manipulation therefore making it dryer some where else. "Axis of evil " was a term used by Reagan but is just as applicable to planet destroying nations that really need direct action to bring them to brook for their irresponsible behaviour~

Scooped by Dr. Stefan Gruenwald
Scoop.it!

Astrobiology and sustainability: What's the average life-span of a civilization in the universe?

Astrobiology and sustainability: What's the average life-span of a civilization in the universe? | Amazing Science | Scoop.it

What exactly is the average lifetime of a technological civilization? 500 years? 50,000 years? Much depends upon the answer, for it helps us calculate the likelihood that other civilizations are out there, some of them perhaps making it through the challenges of adapting to technology and using it to spread into the cosmos. A high number would also imply that we too can make it through the tricky transition and hope for a future among the stars.


Sullivan, University of Washington, and Frank, University of Rochester, believe that even if the chances of a technological society emerging are as few as one in 1000 trillion, there will still have been 1000 instances of such societies undergoing transitions like ours in “our local region of the cosmos.” The authors refer to extraterrestrial civilizations as Species with Energy-Intensive Technology (SWEIT) and discuss issues of sustainability that begin with planetary habitability and extend to mass extinctions and their relation to today’s Anthropocene epoch, as well as changes in atmospheric chemistry, comparing what we see today with previous eras of climate alteration, such as the so-called Great Oxidation Event, the dramatic increase in oxygen levels (by a factor of at least 104) that occurred some 2.4 billion years ago.


Out of this comes a suggested research program that models SWEIT evolution and the evolution of the planet on which it arises, using dynamical systems theory as a theoretical methodology. As with our own culture, these ‘trajectories’ (development paths) are tied to the interactions between the species and the planet on which it emerges.


Each SWEIT’s history defines a trajectory in a multi-dimensional solution space with axes representing quantities such as energy consumption rates, population and planetary systems forcing from causes both “natural” and driven by the SWEIT itself. Using dynamical systems theory, these trajectories can be mathematically modeled in order to understand, on the astrobiology side, the histories and mean properties of the ensemble of SWEITs, as well as, on the sustainability science side, our own options today to achieve a viable and desirable future.


Using these modeling techniques could allow us to explore whether the atmospheric changes our own civilization is seeing are an expected outcome for technological societies based on the likely energy sources being used in the early era of technological development. Rapid changes to Earth systems are, the authors note, not a new phenomenon, but as far as we know, this is the first time where the primary agent of causation is watching it happen.


Sustainability emerges as a subset of the larger frame of habitability. Finding the best pathways forward involves the perspectives of astrobiology and planetary evolution, both of which imply planetary survival but no necessary survival for a particular species. Although we know of no extraterrestrial life forms at this time, this does not stop us from proceeding, because any civilization using energy to work with technology is also generating entropy, a fact that creates feedback effects on the habitability of the home planet that can be modeled.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Frilled Sharks - Strange and Fascinating Fish of the Deep with a 3 1/2 Year Pregnancy

Frilled Sharks - Strange and Fascinating Fish of the Deep with a 3 1/2 Year Pregnancy | Amazing Science | Scoop.it

The frilled shark is a fascinating and very strange fish that looks more like an eel than a shark. It has a wide head with a huge mouth and a long, slender body. Frilled sharks are sometimes called “living fossils” because they’re thought to be very similar to a prehistoric ancestor which lived millions of years ago. The mouth of the frilled shark is located at the end of the body instead of behind the tip of the snout as in most other sharks. The first pair of gill slits are especially long, extending from the sides of the body to underneath the throat. The gills have frilly structures on their edges, giving the shark its name.


Frilled sharks spend most of their time in deep water close to the sea bottom. Some people suggest that this shark is the basis of the sea serpent legends. It has the right shape to be mistaken for a sea serpent but it isn’t long enough, since it reaches a maximum length of only just under two meters.


Two living species of frilled sharks have been discovered. We know more about Chlamydoselachus anguineus, known simply as the “frilled shark”, than about the African frilled shark, Chlamydoselachus africana. Even so, there are lots of unanswered questions about the lives of these fish.


The frilled shark has a wide range in both the Pacific and the Atlantic Oceans, but it's found in only scattered patches in these areas. It may live in water as deep as 1000 to 1500 meters below the ocean surface, but it's usually located at depths between 500 and 1000 meters. In some Japanese waters frilled sharks have been found at depths between 50 and 200 meters.


The frilled shark is said to have an "ovoviviparous" method of reproduction, like many other sharks. The eggs are retained in the female's body instead of being laid. The embryos feed on the egg yolk inside the eggs. The eggs hatch inside the female's body and the pups are born live.


The frilled shark is believed to have a slow metabolism, since it lives mainly in cold, deep water. The development of the pups is also slow. It's thought that a three and a half year gestation period may be needed, which would be the longest of any vertebrate. Around six pups are born on average, although the number ranges from two to fifteen. In Japanese waters, and perhaps in other areas too, frilled sharks breed at any time of the year.


more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Doomsday Clock Set at 3 Minutes to Midnight

Doomsday Clock Set at 3 Minutes to Midnight | Amazing Science | Scoop.it
Frustrated with a lack of international action to address climate change and shrink nuclear arsenals, The Bulletin of the Atomic Scientists decided to push the minute hand of its iconic Doomsday Clock to 11:57.


It's the first time the clock hands have moved in three years; since 2012, the clock had been fixed at 5 minutes to symbolic doom, midnight. The Bulletin of the Atomic Scientists doesn't use the clock to make any real doomsday predictions. Rather, the clock is a visual metaphor to warn the public about how close the world is to a potentially civilization-ending catastrophe. Each year, the magazine's board analyzes threats to humanity's survival to decide where the Doomsday Clock's hands should be set.


Experts on the board said they felt a sense of urgency this year because of the world's ongoing addiction to fossil fuels, procrastination with enacting laws to cut greenhouse gas emissions and slow efforts to get rid of nuclear weapons.


Sharon Squassoni, a board member and director of the Proliferation Prevention Program at the Center for Strategic and International Studies, said nuclear disarmament efforts have "ground to a halt" and many nations are expanding, not scaling back, their nuclear capabilities. Russia is upgrading its nuclear program, India plans to expand its nuclear submarine fleet, and Pakistan has reportedly started operating a third plutonium reactor, Squassoni said. She also said the United States has good rhetoric on nuclear nonproliferation, but at the same time is in the midst of a $335 billion overhaul of its nuclear program.


"The risk from nuclear weapons is not that someone is going to press the button, but the existence of these weapons costs a lot of time, effort and money to keep them secure," Squassoni said, adding that there have been troubling safety discrepancies reported in recent years at power plants. The Bulletin of the Atomic Scientists was founded in 1945 by scientists who created the atomic bomb as part of the Manhattan Project and wanted to raise awareness about the dangers of nuclear technology.


The Doomsday Clock first appeared on a cover of the magazine in 1947, with its hands set at 11:53 p.m. The clock's hands shifted quite a bit over the following seven decades. They were closest to midnight in 1953, set at 11:58 p.m., after both the United States and the Soviet Union conducted their first tests of the hydrogen bomb. The clock's hands were pushed all the way back to 11:43 p.m., 17 minutes to midnight, in December 1991, after the world's superpowers signed the Strategic Arms Reduction Treaty, which at the time, seemed like a promising move toward nuclear disarmament.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Qubits as detectors show that space is not squeezed

Qubits as detectors show that space is not squeezed | Amazing Science | Scoop.it
Ever since Einstein proposed his special theory of relativity in 1905, physics and cosmology have been based on the assumption that space looks the same in all directions -- that it's not squeezed in one direction relative to another. A new experiment by physicists used partially entangled atoms -- identical to the qubits in a quantum computer -- to demonstrate more precisely than ever before that this is true: to one part in a billion billion.


The classic experiment that inspired Albert Einstein was performed in Cleveland by Albert Michelson and Edward Morley in 1887 and disproved the existence of an "ether" permeating space through which light was thought to move like a wave through water. What it also proved, said Hartmut Häffner, a UC Berkeley assistant professor of physics, is that space is isotropic and that light travels at the same speed up, down and sideways.


"Michelson and Morley proved that space is not squeezed," Häffner said. "This isotropy is fundamental to all physics, including the Standard Model of physics. If you take away isotropy, the whole Standard Model will collapse. That is why people are interested in testing this."


The Standard Model of particle physics describes how all fundamental particles interact, and requires that all particles and fields be invariant under Lorentz transformations, and in particular that they behave the same no matter what direction they move.


Häffner and his team conducted an experiment analogous to the Michelson-Morley experiment, but with electrons instead of photons of light. In a vacuum chamber he and his colleagues isolated two calcium ions, partially entangled them as in a quantum computer, and then monitored the electron energies in the ions as Earth rotated over 24 hours.


If space were squeezed in one or more directions, the energy of the electrons would change with a 12-hour period. It didn't, showing that space is in fact isotropic to one part in a billion billion (1018), 100 times better than previous experiments involving electrons, and five times better than experiments like Michelson and Morley's that used light.


The results disprove at least one theory that extends the Standard Model by assuming some anisotropy of space, he said.


Häffner and his colleagues, including former graduate student Thaned Pruttivarasin, now at the Quantum Metrology Laboratory in Saitama, Japan, will report their findings in the Jan. 29 issue of the journal Nature.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

11.2 Billion-year-old ancient star system reveals Earth-sized planets forming near start of universe

11.2 Billion-year-old ancient star system reveals Earth-sized planets forming near start of universe | Amazing Science | Scoop.it

A Sun-like star with orbiting planets, dating back to the dawn of the Galaxy, has been discovered by an international team of astronomers. At 11.2 billion years old, it is the oldest star with Earth-sized planets ever found and proves that such planets have formed throughout the history of the Universe.


The discovery, announced on 28 January (AEDT) in the Astrophysical Journal, used observations made by NASA's Kepler satellite. The scientific collaboration was led by the University of Birmingham and contributed to by the University of Sydney.


The star, named Kepler-444, hosts five planets smaller than Earth, with sizes varying between those of Mercury and Venus. "We've never seen anything like this -- it is such an old star and the large number of small planets make it very special," said Dr Daniel Huber from the University's School of Physics and an author on the paper. "It is extraordinary that such an ancient system of terrestrial-sized planets formed when the universe was just starting out, at a fifth its current age. Kepler-444 is two and a half times older than our solar system, which is only a youthful 4.5 billion years old.


"This tells us that planets this size have formed for most of the history of the universe and we are much better placed to understand exactly when this began happening." Dr Tiago Campante, the research leader from the University of Birmingham said, "We now know that Earth-sized planets have formed throughout most of the Universe's 13.8-billion-year history, which could provide scope for the existence of ancient life in the Galaxy."


Together with their international colleagues the University's astronomy team used asteroseismology to determine the age of the star and planets. This technique measures oscillations -- the natural resonances of the host star caused by sound waves trapped within it.


They lead to miniscule changes or pulses in the star's brightness and allow researchers to measure its diameter, mass, and age. The presence and size of the planets is detected by the dimming that occurs when the planets pass across the face of the star. This fading in the intensity of the light received from the star enables scientists to accurately measure the sizes of the planets relative to the size of the star.


"When asteroseismology emerged about two decades ago we could only use it on the Sun and a few bright stars, but thanks to Kepler we can now apply the technique to literally thousands of stars. Asteroseismology allows us to precisely measure the radius of Kepler-444 and hence the sizes of its planets. For the smallest planet in the Kepler-444 system, which is slightly larger than Mercury, we measured its size with an uncertainty of only 100km," Dr Huber said.


more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Promising use of nanodiamonds to kill chemoresistant cancer stem cells more effectively

Promising use of nanodiamonds to kill chemoresistant cancer stem cells more effectively | Amazing Science | Scoop.it

A study led by the National University of Singapore (NUS) found that attaching chemotherapy drug Epirubicin to nanodiamonds effectively eliminates chemoresistant cancer stem cells. The findings were first published online in ACS Nano, the official journal of the American Chemical Society, in December 2014.


The research team, led by Assistant Professor Edward Chow, Junior Principal Investigator at the Cancer Science Institute of Singapore (CSI Singapore) at NUS, demonstrated the use of nanotechnology to repurpose existing chemotherapy drugs as effective agents against chemoresistant cancer stem cells. Chemoresistance, which is the ability of cancer cells to escape chemotherapy treatment, is a primary cause of treatment failure in cancer. Cancer stem cells, a type of cancer cell which initiates the formation of tumours, are commonly found to be more resistant to chemotherapy than the rest of the bulk tumour, which can lead to cancer recurrence following chemotherapy treatment. As such, there is intense interest in developing new drugs or treatment strategies that overcome chemoresistance, particularly in cancer stem cells.


In this study, widely-used chemotherapy drug Epirubicin was attached to nanodiamonds, carbon structures with a diameter of about five nanometres, to develop a nanodiamond-Epirubicin drug delivery complex (EPND). The researchers found that while both standard Epirubicin as well as EPND were capable of killing normal cancer cells, only EPND was capable of killing chemoresistant cancer stem cells and preventing secondary tumour formation in xenograft models of liver cancer.


Compared to other approaches such as combinatorial therapy of chemotherapy drugs with inhibitors of chemoresistance pathways, delivery of existing chemotherapy drugs with nanomaterials, in this case nanodiamonds, provide a broader range of protection in a package that is both safer and more effective. The study showed that delivery of Epirubicin by nanodiamonds resulted in a normally lethal dosage of Epirubicin becoming a safe and effective dosage. As such, delivery of chemotherapy drugs by nanodiamonds not only enables enhanced killing of chemoresistant cancer stem cells, but may be a useful alternative for patients who cannot tolerate the toxic side effects of standard chemotherapy drugs.


Furthermore, the versatility of the nanodiamond-based drug delivery platform opens up the possibility of future applications of nanodiamonds such as the addition of other similar drugs as well as active targeting components such as antibodies or peptides against tumour cell surface proteins for targeted drug release. In addition, the application of a nanodiamond-drug delivery system is not limited to liver cancer. It offers a promising approach to treating a broad range of difficult cancers, particularly those driven by chemoresistant cancer stem cells. In collaboration with Professor Dean Ho at the University of California Los Angeles and Professor Li Jianzhong at Peking University, Asst Prof Chow's group is working towards completing preclinical work on anthracycline delivery by nanodiamonds and hope to begin clinical trials in the near future.

more...
GLG Pharma's curator insight, February 6, 2015 7:54 AM

Cool new technology!

Scooped by Dr. Stefan Gruenwald
Scoop.it!

Laser may replace copper in computer chips for high-speed, low-energy data transmission

Laser may replace copper in computer chips for high-speed, low-energy data transmission | Amazing Science | Scoop.it

An international team of scientists has constructed the first germanium-tin* semiconductor laser for CMOS silicon chips. By replacing copper wires with optical transmission, the new device promises higher-speed data transmission on computer chips at a fraction of the energy.

The results by scientists from Forschungszentrum Jülich and the Paul Scherrer Institute in Switzerland in cooperation with international partners were published in the journal Nature Photonics.


Transferring data between multiple cores and between logic elements and memory cells is a key bottleneck in fast-developing computer technology. “Signal transmission via copper wires limits the development of larger and faster computers due to the thermal load and the limited bandwidth of copper wires,” explains Prof. Detlev Grützmacher, Director at the Forschungszentrum Jülich Peter Grünberg Institute. “The clock signal alone uses up to 30% of the energy, which can be saved through optical transmission.”


The more than 10% tin content is what enables the new germanium-tin semiconductor optical properties, according to the scientists. The laser is currently limited to low temperatures of up to minus 183 degrees Celsius in the test system. The next big step will be generating laser light with electricity, and without the need for cooling, if possible. The aim is to create an electrically pumped laser that functions at room temperature.


*The basis of chip manufacturing is silicon, an element of main group IV of the periodic table. Typical semiconductor lasers for telecommunication systems, made of gallium arsenide for example, however, are costly and consist of elements from main groups III or V. This has profound consequences on the crystal properties. Such laser components cannot therefore be applied directly onto silicon. They have to be produced externally at great effort and subsequently glued to the silicon wafer. However, the lifetime of this kind of component is greatly reduced due to the fact that the thermal expansion coefficients of these elements are significantly different from that of silicon. In contrast, semiconductors of main group IV — to which both silicon and germanium belong — can be integrated into the manufacturing process without any major difficulties. Neither element by itself is very efficient as a light source, however. They are classed among the indirect semiconductors. In contrast to direct semiconductors, they emit mostly heat and only a little light when excited.

The scientists at Jülich’s Peter Grünberg Institute have now for the first time succeeded in creating a “real” direct main group IV semiconductor laser by combining germanium and tin, which is also classed in main group IV.

more...
No comment yet.