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NASA: Cassini Spacecraft Maps 101 Geysers and More on Icy Saturn Moon Enceladus

NASA: Cassini Spacecraft Maps 101 Geysers and More on Icy Saturn Moon Enceladus | Amazing Science | Scoop.it
Scientists using mission data from NASA's Cassini spacecraft have identified 101 distinct geysers erupting on Saturn's icy moon Enceladus.


This graphic shows a 3-D model of 98 geysers whose source locations and tilts were found in a Cassini imaging survey of Enceladus' south polar terrain by the method of triangulation. While some jets are strongly tilted, it is clear the jets on average lie in four distinct "planes" that are normal to the surface at their source location.


Dotted vectors indicate five jets whose sources were determined from images acquired too closely in time to determine tilts accurately. Consequently their 3-D configuration has a large uncertainty associated with it. Two geysers, indicated by crosses in PIA17188, have no tilt determinations at all and are not shown here.


A movie showing a 360-degree view of this model is also presented here. The still graphic and the movie illustrate some of the findings reported in a paper by Porco, DiNino, and Nimmo, and published in the online version of the Astronomical Journal in July 2014: http://dx.doi.org/10.1088/0004-6256/148/3/46. .


Post-equinox images like this, clearly showing the different projected locations of the intersection between the shadow and the curtain of jets from each fracture, were useful for scientists in checking the triangulated positions of the geysers, as described in a paper by Porco, DiNino, and Nimmo, and published in the online version of the Astronomical Journal in July 2014: http://dx.doi.org/10.1088/0004-6256/148/3/45.


A companion paper, by Nimmo et al. is available at: http://dx.doi.org/10.1088/0004-6256/148/3/46.


The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.


For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org.

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

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Human embryos make viral proteins within days of fertilization, a new study shows

Human embryos make viral proteins within days of fertilization, a new study shows | Amazing Science | Scoop.it

A fertilized human egg may seem like the ultimate blank slate. But within days of fertilization, the growing mass of cells activates not only human genes but also viral DNA lingering in the human genome from ancient infections. Now researchers at the Stanford University School of Medicine have found that the early human cells produce viral proteins, and even become crowded with what appear to be assembled viral particles. These viral proteins could manipulate some of the earliest steps in human development, affecting gene expression and even possibly protecting the cells from further viral infection.


The finding raises questions as to who, or what, is really pulling the strings during human embryogenesis. “It’s both fascinating and a little creepy,” said Joanna Wysocka, PhD, associate professor of developmental biology and of chemical and systems biology. “We’ve discovered that a specific class of viruses that invaded the human genome during recent evolution becomes reactivated in the early development of the human embryo, leading to the presence of viral-like particles and proteins in the human cells.” A paper describing the findings was published online April 20 in Nature.


Retroviruses are a class of virus that insert their DNA into the genome of the host cell for later reactivation. In this stealth mode, the virus bides its time, taking advantage of cellular DNA replication to spread to each of an infected cell’s progeny every time the cell divides. HIV is one well-known example of a retrovirus that infects humans.


When a retrovirus infects a germ cell, which makes sperm and eggs, or infects a very early-stage embryo before the germ cells have arisen, the viral DNA is passed along to future generations. Over evolutionary time, however, these viral genomes often become mutated and inactivated. About 8 percent of the human genome is made up of viral sequences left behind during past infections.


One retrovirus, HERVK, however, infected humans repeatedly until relatively recently — within about 200,000 years. Much of HERVK’s genome is still snuggled, intact, in each of our cells.

Most of these sequences are inactive in mature cells, but recent research has shown that they can spring to life in tumor cells or in human embryonic stem cells. A study published in February in Cell Stem Cell by researchers from Singapore’s Genome Institute showed that sequences from a primate virus called HERVH are also activated in early human development.


Now the Stanford researchers have shown for the first time that viral proteins are abundantly present in the developing human embryo and assemble into what appear to be viral particles in electron microscopy images. By following up with additional studies in human embryonic cells grown in vitro, scientists showed that these viral proteins affect gene expression in the developing embryo and may protect the cells from infection by other viruses.


But it’s not clear whether this sequence of events is the result of thousands of years of co-existence, a kind of evolutionary symbiosis, or if it represents an ongoing battle between humans and viruses. “Does the virus selfishly benefit by switching itself on in these early embryonic cells?” said Grow. “Or is the embryo instead commandeering the viral proteins to protect itself? Can they both benefit? That’s possible, but we don’t really know.”

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Propagating mutations throughout an entire population: What are the risks and rewards?

Propagating mutations throughout an entire population: What are the risks and rewards? | Amazing Science | Scoop.it

Major strides in genetics from Gregor Mendel to Barbara McClintock have changed the way we see how genes are inherited. Because of this, we can calculate with reasonable confidence how genes will propagate from one generation to the next. But what if a scientist wants to bias how some alleles are transmitted, increasing their chance of being spread to the next generation? This already happens in the natural world. Transposable elements, for example, can insert and remove themselves throughout the genome. In a recent article, scientists developed an ingenious technique to create homozygous mutations that pass themselves to the next generation. This method can completely transform the genome of an entire population after several generations. Using the CRISPR-Cas9 system, Scientists from UC- San Diego created a mutagenic chain reaction (MCR) to greatly alter how genes are inherited.


To start, the researchers developed a bacterial construct that contained a Cas9 endonuclease and a gRNA that targets a gene of interest surrounded by homology arms that match sequences in the gene of interest. They inject this construct along with already made Cas9s and gRNAs to cut one allele of the gene and allow the construct to integrate using homologous recombination. The inserted construct will be transcribed, creating the Cas9 and gRNA which will then make a cut on the other chromosome. This allows for another round of homologous recombination, and the knockout of the other allele of the gene. This will interrupt the gene of interest, likely rendering it silent. Not only will insertion help create double knockouts, but when passed on to the next generation, the normally heterozygous mutations will now knockout the allele inherited from the other parent. This will create homozygous knockout progeny.


Their work show that after incorporating the cassette as an embryo, flies would emerge as homozygous knockouts. Even more incredible, the next generation showed complete knockouts. The gRNA targeted a gene in the X chromosome, that when homozygously mutated produced a lighter, yellow tinted fly. If the cassette was injected into a male fly, knocking out the gene, and this fly then mated with a wild type female, they found 100% of the female progeny were homozygous mutants, yellow, and all the males were wild type, a normal color. If the cassette was injected into a female fly, and mated to a wild type male fly, the investigators found 97% of the progeny were homozygous knockouts. In normal Mendelian crosses, one would expect 0% of the progeny to be homozygous for the knockout.


One name for such a system is a gene drive. The idea has been around since the 1960s and has picked up steam in the past years. Until recently, it had remained theoretical. However, with the major advances in genome engineering, it has now become a reality. We have seen similar work to what is presented here done in yeast at George Church's lab at Harvard. This technique has a lot of pros. It drastically decreases the amount of time it takes to make a stable mutant line. Also, there is less risk losing the mutation through mishaps with breeding (although this could be seen as a con if one fly escapes into another mutant line). Doing genetic screens too will be far easier and faster with this technique. A key use for this system is delivering transgenes into pests or disease carrying insects like mosquitos to help eradicate the spread of deadly diseases. In a similar vein, gene drives could help control invasive species. There are, however, some severe downsides to this method.


The most obvious downside to willingly releasing an organism into the wild with a gene drive are unseen results of the mutation. Nearly permanent changes introduced into a species will likely have many unknown effects on the population and environment. Furthermore, other mutations could occur through chance or off-target effects creating unforeseen mutants. Releasing these creatures into the wild in the hopes it will change the species for the better is incredibly hazardous. The risk of working with this protocol in the lab has drawbacks as well. If one is working with animals like flies or mice (although, to my knowledge, this hasn't been tested in mice), they can escape labs and potentially spread the homozygous mutations to the wild populations. There is a chance that the induced mutation would decrease the fitness of the animals, eventually weeding itself out of the population, but that isn't something we can depend on.


The authors acknowledged that there are substantial risks involved with such an experiment. They went through extensive steps to prevent the escape of animals. To George Church, however, it's the escape of the protocol that is dangerous. My thoughts are that with enough regulation, research with these methods can be done safely, but it must be taken seriously. There are several measures that would limit the broad impact of the experiments. One could target specific genes only found in a small subset of the greater population. Propagation could also be made in a way that it is easily reversible. In the work linked to above using gene drives in yeast, the authors split the locations of the Cas9 and gRNA, preventing the organism from being completely sufficient in driving changes throughout the population. The broader impacts of gene drives are enormous and we must take strides early by starting a dialogue and holding regulatory meetings to prevent any catastrophe.


Gene drives present an ethical conundrum. There is a thin line between positive results, and potentially dangerous mutations running rampant. It is imperative that measures are put in place quickly to contain all aspects of the materials and limit outside exposure. The invention and use of such a superb technique needs to be used safely and with great care.


References:


Bohannon, J. Biologists devise invasion plan for mutations. Science, 347, 1300 (2015).


Burt, A. Site-Specific selfish genes as tool for the control and genetic engineering of natural populations. Proceedings of the biological sciences B, 270, 921-928 (2003).


Esvelt, K.M., Smidler, A.L., Catteruccia, F., Church, G.M. Concerning RNA-guided gene drives for the alteration of wild populations. eLife, 2014;3:e03401.


Gantz, V.M., Bier, E. The mutagenic chain reaction: A method for converting heterozygous to homozygous mutations. Science Express, DOI: 10.1126/science.aaa5945 (2015).


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Is this ET? Mystery of strange radio bursts from space

Is this ET? Mystery of strange radio bursts from space | Amazing Science | Scoop.it

Mysterious radio wave flashes from far outside the galaxy are proving tough for astronomers to explain. Is it pulsars? A spy satellite? Or an alien message?


BURSTS of radio waves flashing across the sky seem to follow a mathematical pattern. If the pattern is real, either some strange celestial physics is going on, or the bursts are artificial, produced by human – or alien – technology. Telescopes have been picking up so-called fast radio bursts (FRBs) since 2001. They last just a few milliseconds and erupt with about as much energy as the sun releases in a month. Ten have been detected so far, most recently in 2014, when the Parkes Telescope in New South Wales, Australia, caught a burst in action for the first time. The others were found by sifting through data after the bursts had arrived at Earth. No one knows what causes them, but the brevity of the bursts means their source has to be small – hundreds of kilometres across at most – so they can't be from ordinary stars. And they seem to come from far outside the galaxy. The weird part is that they all fit a pattern that doesn't match what we know about cosmic physics.


To calculate how far the bursts have come, astronomers use a concept called the dispersion measure. Each burst covers a range of radio frequencies, as if the whole FM band were playing the same song. But electrons in space scatter and delay the radiation, so that higher frequency waves make it across space faster than lower frequency waves. The more space the signal crosses, the bigger the difference, or dispersion measure, between the arrival time of high and low frequencies – and the further the signal has travelled.


Michael Hippke of the Institute for Data Analysis in Neukirchen-Vluyn, Germany, and John Learned at the University of Hawaii in Manoa found that all 10 bursts' dispersion measures are multiples of a single number: 187.5 (see chart). This neat line-up, if taken at face value, would imply five sources for the bursts all at regularly spaced distances from Earth, billions of light-years away. A more likely explanation, Hippke and Lerned say, is that the FRBs all come from somewhere much closer to home, from a group of objects within the Milky Way that naturally emit shorter-frequency radio waves after higher-frequency ones, with a delay that is a multiple of 187.5 (arxiv.org/abs/1503.05245).


They claim there is a 5 in 10,000 probability that the line-up is coincidence. "If the pattern is real," says Learned, "it is very, very hard to explain." Cosmic objects might, by some natural but unknown process, produce dispersions in regular steps. Small, dense remnant stars called pulsars are known to emit bursts of radio waves, though not in regular arrangements or with as much power as FRBs. But maybe superdense stars are mathematical oddities because of underlying physics we don't understand.


It's also possible that the telescopes are picking up evidence of human technology, like an unmapped spy satellite, masquerading as signals from deep space. The most tantalising possibility is that the source of the bursts might be a who, not a what. If none of the natural explanations pan out, their paper concludes, "An artificial source (human or non-human) must be considered."


"Beacon from extraterrestrials" has always been on the list of weird possible origins for these bursts. "These have been intriguing as an engineered signal, or evidence of extraterrestrial technology, since the first was discovered," says Jill Tarter, former director of the SETI Institute in California. "I'm intrigued. Astronomers have long speculated that a mathematically clever message – broadcasts encoded with pi, or flashes that count out prime numbers, as sent by aliens in the film Contact – could give away aliens' existence. Perhaps extraterrestrial civilizations are flagging us down with basic multiplication. Stay tuned."

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Proto-suns teeming with prebiotic molecules which can lead to sugars, amino acids and nucleotides

Proto-suns teeming with prebiotic molecules which can lead to sugars, amino acids and nucleotides | Amazing Science | Scoop.it

One of science’s greatest challenges is learning about the origin of life and its precursor molecules. Formamide (NH2CHO) is an excellent candidate for helping to search for answers as it contains four essential elements (nitrogen, hydrogen, carbon and oxygen), and can synthesise amino acids, carbohydrates, nucleic acids and other key compounds for living organisms.


However, this molecule is also abundant in space, mainly in molecular clouds or the concentrations of gas and dust where stars are born. This has been confirmed by an international team of researchers, including Spanish investigators, after searching for formamide in ten star-forming regions.


“We have detected formamide in five protosuns, which proves that this molecule (in all probability also true for our Solar System) is relatively abundant in molecular clouds and is formed in the very early stages of evolution towards a star and its planets,” explains Ana López Sepulcre, lead author of the study and researcher at the University of Tokyo (Japan), to SINC.


The other five objects where formamide has not been detected are less evolved and colder, “which indicates that a minimum temperature is needed for it to be detected in the gas,” adds the scientist. The study, which has just been published in the ‘Monthly Notices of the Royal Astronomical Society’, also offers clues on how formamide could be created in interstellar conditions. “We propose that it is formed on the surface of the dust grains of the molecular clouds from isocyanic acid (HNCO), by a process of hydrogenation or addition of hydrogen atoms,” says López Sepulcre.


“Formamide formed in this way remains attached to the dust grain until the temperature is high enough (in other words, until the protostar evolves) to cause its sublimation,” she argues. “And that is when we can detect it with radio telescopes”.


Yet formamide is not the only potentially prebiotic organic molecule analysed in space. Just this month the detection of methyl cyanide (CH3CN) around the young star MWC 480, already in a protoplanetary stage, has been published in the journal ‘Nature’.


“This other study demonstrates that complex molecules survive until the later stages of stellar formation, and even continue forming afterwards,” López Sepulcre notes, but formamide does have some advantages: “It contains oxygen (another essential element for life) and is a strong candidate as a precursor of prebiotic material, as not only amino acids can be formed from it (which could also be synthesised from CH3CN), but also nucleic acids and bases, or rather genetic material”.


“This proves the significance of our study,” emphasises the researcher, who sums it up as: “formamide, a significant biomolecule, is already formed in regions where stars like our Sun are born in the very early stages and in relatively high amounts”.


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Giant Galaxies Die From Within When They Stop Making Stars

Giant Galaxies Die From Within When They Stop Making Stars | Amazing Science | Scoop.it

Galaxies are star factories. But for some, such as massive elliptical galaxies, their star-forming days are now over. All of their available gas has already been turned into more than a hundred billion stars. Collectively, these galaxies contain about half of all the stars that have ever existed in the universe.


In a new study, published in Science, astronomers have tracked down how the fire of star formation burnt out within these galaxies. It appears that most of the time, the star formation is first quenched within the heart of the galaxy, and it’s not until a few billion years later that the outer regions run out of gas and stop producing stars.


This discovery that giant galaxies die from the inside-out is useful for astronomers trying to understand the mechanisms that promote and hinder star formation. And, ultimately, it’s about unravelling the history of the universe and understanding why we see the kinds of galaxies that exist today.


The light emitted from the 22 galaxies investigated in this study has taken more than 10 billion years to reach us. We are seeing these galaxies from a time when the universe was around three billion years old. It was the heyday of the universe, when galaxies were vigorously forming stars at a rate about 20 times faster than occurs today. Each year, massive galaxies were producing the equivalent of hundreds of sun-like stars. In comparison, our Milky Way Galaxy creates just four sun-like stars a year.


And when the universe was young, it was the most massive galaxies that were undergoingthe fastest growth, as confirmed by the Galaxy and Mass Assembly (GAMA) project, a major study being undertaken in Australia with the Anglo-Australian TelescopeSo how does the growth slow down?


To answer this, PhD student Sandro Tacchella (ETH Zurich, Switzerland) and colleagues used observations from both the Hubble Space Telescope (HST) and the European Southern Observatory’s Very Large Telescope (VLT). Images from the HST, were used to trace the distribution of older stars within the galaxies – the locations where star formation had previously occurred. Using an instrument known as SINFONI on the VLT, the astronomers looked for regions where star formation was actively occurring. This is done by searching for hydrogen gas that has been excited or ionized by the radiation emitted from young, hot stars.


To be useful, both sets of observations needed to track changes across small spatial scales. The HST can do this because it’s in space and doesn’t have to deal with the blurring effects of the Earth’s atmosphere. It’s harder for the VLT to resolve small parts of the distant galaxies because the telescope sits on Earth’s surface, in Chile, and must cancel out Earth’s atmospheric effects. The VLT does this by monitoring an artificial star (produced by a laser), then keeps the starlight steady by deforming its mirrors, making the results even more impressive.

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Artificial Photosynthesis Advance Hailed As Major Breakthrough

Artificial Photosynthesis Advance Hailed As Major Breakthrough | Amazing Science | Scoop.it

In what's being called a win-win for the environment and the production of renewable energy, researchers at Lawrence Berkeley National Laboratory and the University of California, Berkeley, have achieved a major breakthrough in artificial photosynthesisThe scientists have created a system that can capture carbon dioxide emissions before they're released into the atmosphere and convert it into fuels, pharmaceuticals, plastics, and other valuable products.


Carbon dioxide is the principal greenhouse gas produced by the burning of fossil fuels and has been identified as a major contributor to rising global temperatures"Our system has the potential to fundamentally change the chemical and oil industry in that we can produce chemicals and fuels in a totally renewable way, rather than extracting them from deep below the ground," Dr. Peidong Yang, a chemist with the materials sciences division at Berkeley Lab and one of the researchers behind the breakthrough, said in a written statement.


Scientists around the world have spent decades looking for a practical way to mimic photosynthesis. That's the process in which green plants use energy from sunlight to convert water and carbon dioxide into oxygen and carbohydrates. But it's proven to be a difficult technical challenge.


"The real issue comes from the balance of energy efficiency, cost, and stability, Dr. Amanda J. Morris, assistant professor of chemistry at Virginia Tech in Blacksburg and an expert in sustainable energy, told The Huffington Post in an email. "Electrons, which are required, are very expensive (either produced from gasoline, oil, coal or solar) and so, the process must be very efficient in terms of electron and energy balances."


Morris, who was not involved in the new research, called it "important," adding that it would guide future efforts in the field. The heart of the new system is an array of minute silicon and titanium oxide wires studded with Sporomusa ovata bacteria. The "nanowires" capture light energy and deliver it the bacteria, which convert carbon dioxide in the air into acetatea key building block for the more complex organic molecules in fuels, biodegradable plastics, and pharmaceuticals.


"We are currently working on our second-generation system, which has a solar-to-chemical conversion efficiency of 3 percent," Yang said in the statement. "Once we can reach a conversion efficiency of 10 percent in a cost-effective manner, the technology should be commercially viable."

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Cold Spot suggests largest structure in the observable universe is a supervoid 1.3 billion light years across

Cold Spot suggests largest structure in the observable universe is a supervoid 1.3 billion light years across | Amazing Science | Scoop.it

In 2004, astronomers examining a map of the radiation left over from the Big Bang discovered the Cold Spot, a larger-than-expected unusually cold area of the sky. The physics surrounding the Big Bang theory predicts warmer and cooler spots of various sizes in the infant universe, but a spot this large and this cold was unexpected.


Now, a team of astronomers led by Dr István Szapudi of the Institute for Astronomy at the University of Hawaii at Manoa may have found an explanation for the existence of the Cold Spot, which Szapudi says may be "the largest individual structure ever identified by humanity." The researchers report their findings in the journal Monthly Notices of the Royal Astronomical Society.


If the Cold Spot originated from the Big Bang itself, it could be a rare sign of exotic physics that the standard cosmology (basically, the Big Bang theory and related physics) does not explain. If, however, it is caused by a foreground structure between us and the CMB, it would be a sign that there is an extremely rare large-scale structure in the mass distribution of the universe.


Using data from Hawaii's Pan-STARRS1 (PS1) telescope located on Haleakala, Maui, and NASA's Wide Field Survey Explorer (WISE) satellite, Szapudi's team discovered a large supervoid, a vast region 1.8 billion light-years across, in which the density of galaxies is much lower than usual in the known universe. This void was found by combining observations taken by PS1 at optical wavelengths with observations taken by WISE at infrared wavelengths to estimate the distance to and position of each galaxy in that part of the sky.


Earlier studies, also done in Hawaii, observed a much smaller area in the direction of the Cold Spot, but they could establish only that no very distant structure is in that part of the sky. Paradoxically, identifying nearby large structures is harder than finding distant ones, since we must map larger portions of the sky to see the closer structures. The large three-dimensional sky maps created from PS1 and WISE by Dr András Kovács (Eötvös Loránd University, Budapest, Hungary) were thus essential for this study. The supervoid is only about 3 billion light-years away from us, a relatively short distance in the cosmic scheme of things.


Imagine there is a huge void with very little matter between you (the observer) and the CMB. Now think of the void as a hill. As the light enters the void, it must climb this hill. If the universe were not undergoing accelerating expansion, then the void would not evolve significantly, and light would descend the hill and regain the energy it lost as it exits the void. But with the accelerating expansion, the hill is measurably stretched as the light is traveling over it. By the time the light descends the hill, the hill has gotten flatter than when the light entered, so the light cannot pick up all the speed it lost upon entering the void. The light exits the void with less energy, and therefore at a longer wavelength, which corresponds to a colder temperature.


Getting through a supervoid takes hundreds of millions of years, even at the speed of light, so this measurable effect, known as the Integrated Sachs-Wolfe (ISW) effect, might provide the first explanation of one of the most significant anomalies found to date in the CMB, first by a NASA satellite called the Wilkinson Microwave Anisotropy Probe (WMAP), and more recently, by Planck, a satellite launched by the European Space Agency.

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Mummified bodies from 18th century Europe found to have multiple tuberculosis infections

Mummified bodies from 18th century Europe found to have multiple tuberculosis infections | Amazing Science | Scoop.it

Bodies found in a 200 year-old Hungarian crypt have revealed the secrets of how tuberculosis (TB) took hold in 18th century Europe, according to a research team involving UCL scientists.


A new study published in Nature Communications details how samples taken from naturally mummified bodies found in an 18th century crypt in the Dominican church of Vác in Hungary have yielded 14 TB genomes, suggesting that mixed infections were common when TB was at peak prevalence in Europe.


The research team included collaborators from the Universities of Warwick and Birmingham, UCL, the Hebrew University in Jerusalem and the Hungarian Natural History Museum in Budapest. Lead author Professor Mark Pallen, from Warwick Medical School, said the discovery was significant for current and future infection control and diagnosis.


Professor Pallen said: “Microbiological analyses of samples from contemporary TB patients usually report a single strain of TB per patient. By contrast, five of the eight bodies in our study yielded more than one type of TB – remarkably from one individual we obtained evidence of three distinct strains.”


The team used a technique called “metagenomics” to identify TB DNA in the historical specimens—that is direct sequencing of DNA from samples without growing bacteria or deliberately fishing out TB DNA. This approach draws on the remarkable throughput and ease of use of modern DNA sequencing technologies.

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Electrically controlling quantum bits in silicon may lead to large quantum computers

Electrically controlling quantum bits in silicon may lead to large quantum computers | Amazing Science | Scoop.it

An UNSW-led research team has encoded quantum information in silicon using simple electrical pulses for the first time, bringing the construction of affordable large-scale quantum computers one step closer to reality. The idea is to exploit the advanced fabrication methods developed in semiconductor nanoelectronics and create quantum bits (qubits) that are both highly coherent and easy to control and couple to each other — a challenging task.


The findings were published in the open-access journal Science AdvancesThe UNSW team, which is affiliated with the ARC Centre of Excellence for Quantum Computation & Communication Technology, was first to demonstrate single-atom spin qubits in silicon, reported in Nature in 2012 and 2013. The team later improved the control of these qubits to an accuracy of above 99% and established the world record for how long quantum information can be stored in the solid state, as published in Nature Nanotechnology in 2014.


The researchers have now demonstrated a key step that had remained elusive since 1998: using electric fields instead of pulses of oscillating magnetic fields. Lead researcher Andrea Morello, a UNSW Associate Professor from the School of Electrical Engineering and Telecommunications, said the method works by distorting the shape of the electron cloud attached to the atom, using a very localized electric field. “This distortion at the atomic level has the effect of modifying the frequency at which the electron responds. “Therefore, we can selectively choose which qubit to operate.”


The findings suggest that it would be possible to locally control individual qubits with electric fields in a large-scale quantum computer using only inexpensive voltage generators, rather than requiring expensive high-frequency microwave sources.


Moreover, this specific type of quantum bit can be manufactured by placing qubits inside a thin layer of specially purified silicon, containing only the silicon-28 isotope. “This isotope is perfectly non-magnetic and, unlike those in naturally occurring silicon, does not disturb the quantum bit,” Morello said.


The purified silicon was provided through collaboration with Keio University in Japan.

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New shape-shifting molecule tricks viruses into mutating themselves to death

New shape-shifting molecule tricks viruses into mutating themselves to death | Amazing Science | Scoop.it

A newly developed spectroscopy method is helping to clarify the poorly understood molecular process by which an anti-HIV drug induces lethal mutations in the virus’ genetic material. The findings from the University of Chicago and the Massachusetts Institute of Technology could bolster efforts to develop the next generation of anti-viral treatments.


Viruses can mutate rapidly in order to adapt to environmental pressure. This feature also helps them become resistant to anti-viral drugs. But scientists have developed therapeutic anti-viral agents for HIV, hepatitis C and influenza using a strategy called lethal mutagenesis.

This strategy seeks to extinguish viruses by forcing their already high mutation rates above an intolerable threshold. If viruses experience too many mutations, they can’t properly manage their genetic material.


“They can’t replicate and so are quickly eliminated,” said Andrei Tokmakoff, the Henry G. Gale Distinguished Service Professor in Chemistry at UChicago. “In order to make this work, you need a stealth mutagen. You need something sneaky, something that the virus isn’t going to recognize as a problem.”


Tokmakoff and his associates at UChicago and MIT reported new details of the stealthy workings of the anti-HIV agent KP1212 in March in the Proceedings of the National Academy of Sciences. Supporting data were collected with two-dimensional infrared spectroscopy, an advanced laser technique that combines ultrafast time resolution with high sensitivity to chemical structure.


Scientists design lethally mutagenic molecules such as KP1212 to resemble natural DNA bases, the adenine-thymine, cytosine-guanine base pairs. “These analogs can bind to the wrong base partners and therefore lead to genetic mutations,” said the study’s lead author, Sam Peng, who was a visiting graduate research assistant at UChicago.


KP1212 is a cytosine variation, which normally would pair with guanine during replication. But biochemical experiments and clinical trials have shown that KP1212 induces mutations by pairing with adenine. A leading proposal suggested that KP1212 derived its mutagenicity by shape shifting—converting into a different molecular structure by repositioning its hydrogen atoms on nitrogen and oxygen atoms.


Most experimental tools would have difficulty distinguishing between the normal and shape-shifted structures because they interconvert very rapidly. With two-dimensional infrared spectroscopy, the UChicago team was able to distinguish between the two structures. The team also was able to measure how rapidly the shape shifting occurs under physiological conditions: in 20 billionths of a second.


The research team expected to find only two dominant tautomers, but their experiments showed that many more exist. In addition to taking on different forms as a neutral molecule, KP1212 also could accept an extra proton, giving it a positive charge at physiological levels of acidity—pH of approximately five and a half to seven—that made possible even more rearrangements and tautomer structures.


“The number of possibilities exploded,” Tokmakoff said. The experiments also showed that both the protonated and non-protonated forms facilitated the viral mutation rate. Even in the absence of the protonated form, the virus still mutated, just at a lower rate. “We found that under physiological pHs, KP1212 is significantly protonated and this protonated form induces even higher mutation rates, reaching approximately 50 percent,” Peng said.

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A Scan Of 100,000 Galaxies Shows No Sign Of Alien Mega-Civilizations (K3s)

A Scan Of 100,000 Galaxies Shows No Sign Of Alien Mega-Civilizations (K3s) | Amazing Science | Scoop.it
A pioneering infrared scan of 100,000 galaxies by Penn State astronomers has failed to detect any signs of galaxy-spanning extraterrestrial supercivilizations. This result, though very preliminary, may be a sign that aliens aren't capable of conquering entire galaxies.


Back in the 1960s, Russian cosmologist Nikolai Kardashev devised the famous scale that now bears his name . He proposed a simple numbering system — from one to three — that can be used to classify hypothetical alien civilizations according to the amount of energy at their disposal. According to the scale, a K1 civ has captured the entire energy output of its home planet, while a K2 civ has tapped into all the power produced by its home star.


But then there are K3 civs — so-called supercivilizations — who have tapped into virtually all of the energy produced by their own galaxy. As study co-author Jason Wright told io9: "Type III civilizations in the sense that Nikolai Kardashev originally defined them, were 'maximal' energy users: they command all of the starlight in their galaxy." This could be accomplished by ETIs in any number of ways, including vast complexes of Dyson spheres and the establishment of Matrioshka Brains.


K3 civilizations should be reasonably easy to detect from a distance. According to fundamental thermodynamics, the energy pulled in by a K3 civ must still be radiated away as heat in the mid-infrared wavelengths. These galactic-scale signatures, though far away, can still be detected from Earth.


With this in mind, a team of astronomers from Penn State recently completed a survey, known as the Glimpsing Heat from Alien Technologies Survey (G-HAT), of 100,000 galaxies to see if they could find traces of galaxy-spanning supercivilizations. Their results now appear in theAstrophysical Journal.


The G-HAT team, led by postbaccalaureate researcher Roger Griffith, analyzed practically the entire catalog of detections made by NASA's WISE orbiting observatory. That's nearly 100 million entries. The researchers honed this list down to ~100,000 of the most promising candidates, looking for objects consistent with galaxies emitting too much mid-infrared radiation.


No obvious alien-filled galaxies were detected. That said, 50 galaxies did feature higher-than-usual levels of mid-infrared radiation. Further analysis will be required to determine if they are caused by some natural astronomic process, or if they're an indication of highly advanced extraterrestrial civilizations not filling up the whole galaxy.


This poses a bit of a problem for astrobiologists. Back in 1975, astronomer Michael H. Hart conjectured that super-advanced aliens should be able to colonize an entire galaxy within a reasonably short amount of time, at least from a cosmological perspective. Either that or humanity is alone in the Milky Way. It's this line of reasoning that led the Penn State researchers to conduct their inter-galactic survey. "There has been a line of argument, originating with Michael Hart, that there should not be any advanced civilization in the Milky Way, because if there were, they would have taken over the entire galaxy by now. If this is correct, then a search for civilizations spanning other galaxies is the best approach.


The next step for the G-HAT team is to scale things down a bit to see if less energy-intensive civilizations might exist in these galaxies. This is where Carl Sagan's adjunct to the Kardashev Scale might come in handy. "On Sagan's scale, we want to push down from Type 3.0 to Type 2.9 or 2.8," says Wright. "That is, search for civilizations using 10% or even 1% of the starlight in a galaxy."

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World's Oldest Stone Tools Found That Predate Modern Humans By 500,000 Years

World's Oldest Stone Tools Found That Predate Modern Humans By 500,000 Years | Amazing Science | Scoop.it

Scientists working in East Africa say they've unearthed the oldest stone tools ever found. They were apparently made 500,000 years before the human lineage evolved. A team led by Sonia Harmand from Stony Brook University in New York found the tools in Kenya, near Lake Turkana. It's an area that's yielded numerous fossils and tools from early humans. These newly discovered tools have been reliably dated to 3.3 million years ago, according to scientists who've reviewed the research. That's 700,000 years older than the previous record for the oldest stone tools ever found.


That's remarkable because it's well before the human genus, Homo, emerged 2.8 million years ago. So clearly these early humans didn't make these tools. The team presumes they were made by an early ancestor of humans, probably a member of a genus called Australopithecus. The famous ape-like creature known as Lucy was from that genus and first appeared in Africa about four million years ago.


Leading stone tool experts who've seen the tools say they have the markings of a process called "knapping." Knapping a piece of stone produces flakes that can have sharp edges and are useful for working with plants, nuts or meat. These flakes can be distinguished from naturally occurring pieces of rock. Knapping also leaves characteristic marks on the rock from which the flakes are chipped.


Richard Potts, head of the Human Origins Program at the Smithsonian Institution, has examined the tools. He tells NPR they're a "mixed bag," with some quite crude and others a little more sophisticated. Potts says they're not as advanced as most early human-made tools, but "there's no doubt it's purposeful" tool-making. And it's more sophisticated than the kind of tool-making that chimpanzees do, he adds, such as shaping sticks to probe for termites in their underground mounds.

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Intact Proteins Found in Fossils That Are Supposedly 8-18 Million Years Old

Intact Proteins Found in Fossils That Are Supposedly 8-18 Million Years Old | Amazing Science | Scoop.it
Recently, I ran across a very interesting study that adds to the list of surprises for those who think that some fossils are millions of years old. The authors were analyzing the fossilized shells of an extinct group of marine mollusks from the genus Ecphora. Unlike many mollusk groups, the fossilized shells of the Ecphora are colored reddish-brown. The authors decided to find out what produces this colorization, so they soaked the fossils in weak acid to remove the minerals. What remained were thin sheets of organic residue that had all the characteristics one would expect if they were made of proteins.

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Internet Replacing Radio: Norway Will Be the First Country to Turn Off FM Radio in 2017

Internet Replacing Radio: Norway Will Be the First Country to Turn Off FM Radio in 2017 | Amazing Science | Scoop.it

Norway’s Minister of Culture announced this week that a national FM-radio switch off will commence in 2017, allowing the country to complete its transition over to digital radio. It’s the end of an era.


As Radio.no notes, Digital Audio Broadcasting (DAB) will provide Norwegian listeners more diverse radio channel content than ever before. Indeed, DAB already hosts 22 national channels in Norway, as opposed to FM radio’s five, and a TNS Gallup survey shows that 56% of Norwegian listeners use digital radio every day. While Norway is the first country in the world to set a date for an FM switch-off, other countries in Europe and Southeast Asia are also in the process of transitioning to DAB.


requency modulation, or FM, radio was patented in 1933 and has been recording and sharing the human story for nearly a century. But its days are clearly waning. According to a 2012 Pew Study, while over 90% of Americans still listen to AM/FM radio at least weekly, more people are choosing to forgo analog radio for Internet-only services each year. It seems like it’s only a matter of time before many countries follow Norway’s example, although I’m not so sure I’m ready to part with my 80’s-era Grundig. Thing still sounds like a dream.

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Photon afterglow could transmit information without transmitting energy

Photon afterglow could transmit information without transmitting energy | Amazing Science | Scoop.it

Physicists have theoretically shown that it is possible to transmit information from one location to another without transmitting energy. Instead of using real photons, which always carry energy, the technique uses a small, newly predicted quantum afterglow of virtual photons that do not need to carry energy. Although no energy is transmitted, the receiver must provide the energy needed to detect the incoming signal—similar to the way that an individual must pay to receive a collect call.


The physicists, Robert H. Jonsson, Eduardo Martín-Martínez, and Achim Kempf, at the University of Waterloo (Martín-Martínez and Kempf are also with the Perimeter Institute), have published a paper on the concept in a recent issue of Physical Review LettersCurrently, any information transmission protocol also involves energy transmission. This is because these protocols use real photons to transmit information, and all real photons carry energy, so the information and energy are inherently intertwined.


Most of the time when we talk about electromagnetic fields and photons, we are talking about real photons. The light that reaches our eyes, for example, consists only of real photons, which carry both information and energy. However, all electromagnetic fields contain not only real photons, but also virtual photons, which can be thought of as "imprints on the quantum vacuum." The new discovery shows that, in certain circumstances, virtual photons that do not carry energy can be used to transmit information.


The physicists showed how to achieve this energy-less information transmission by doing two things: "First, we use quantum antennas, i.e., antennas that are in a quantum superposition of states," Kempf told Phys.org. "For example, with current quantum optics technology, atoms can be used as such antennas. Secondly, we use the fact that, when real photons are emitted (and propagate at the speed of light), the photons leave a small afterglow of virtual photons that propagate slower than light. This afterglow does not carry energy (in contrast to real photons), but it does carry information about the event that generated the light. Receivers can 'tap' into that afterglow, spending energy to recover information about light that passed by a long time ago."


The proposed protocol has another somewhat unusual requirement: it can only take place in spacetimes with dimensions in which virtual photons can travel slower than the speed of light. For instance, the afterglow would not occur in our 3+1 dimensional spacetime if spacetime were completely flat. However, our spacetime does have some curvature, and that makes the afterglow possible.


These ideas also have implications for cosmology. In a paper to be published in a future issue of Physical Review Letters, Martín-Martínez and collaborators A. Blasco, L. Garay, and M. Martin-Benito have investigated these implications. "In that work, it is shown that the afterglow of events that happened in the early Universe carries more information than the light that reaches us from those events," Martín-Martínez said. "This is surprising because, up until now, it has been believed that real quanta, such as real photons of light, are the only carriers of information from the early Universe."

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High-intensity magnetic field close to supermassive black hole found

High-intensity magnetic field close to supermassive black hole found | Amazing Science | Scoop.it

The Atacama Large Millimeter/submillimeter Array (ALMA) has revealed an extremely powerful magnetic field, beyond anything previously detected in the core of a galaxy, very close to the event horizon of a supermassive black hole.


This new observation helps astronomers to understand the structure and formation of these massive inhabitants of the centers of galaxies, and the twin high-speed jets of plasma they frequently eject from their poles. The results appear in the 17 April 2015 issue of the journal Science.


Supermassive black holes, often with masses billions of times that of the Sun, are located at the heart of almost all galaxies in the Universe. These black holes can accrete huge amounts of matter in the form of a surrounding disc. While most of this matter is fed into the black hole, some can escape moments before capture and be flung out into space at close to the speed of light as part of a jet of plasma. How this happens is not well understood, although it is thought that strong magnetic fields, acting very close to the event horizon, play a crucial part in this process, helping the matter to escape from the gaping jaws of darkness.


Up to now, only weak magnetic fields far from black holes -- several light-years away -- had been probed. In this study, however, astronomers from Chalmers University of Technology and Onsala Space Observatory in Sweden used ALMA to detect signals directly related to a strong magnetic field very close to the event horizon of the supermassive black hole in a distant galaxy named PKS 1830-211. This magnetic field is located precisely at the place where matter is suddenly boosted away from the black hole in the form of a jet. The team measured the strength of the magnetic field by studying the way in which light was polarized as it moved away from the black hole.


"Polarization is an important property of light and is much used in daily life, for example in sun glasses or 3D glasses at the cinema," says Ivan Marti-Vidal, lead author of this work. "When produced naturally, polarization can be used to measure magnetic fields, since light changes its polarization when it travels through a magnetized medium. In this case, the light that we detected with ALMA had been traveling through material very close to the black hole, a place full of highly magnetized plasma."


The astronomers applied a new analysis technique that they had developed to the ALMA data and found that the direction of polarization of the radiation coming from the center of PKS 1830-211 had rotated. These are the shortest wavelengths ever used in this kind of study, which allow the regions very close to the central black hole to be probed.


"We have found clear signals of polarization rotation that are hundreds of times higher than the highest ever found in the Universe," says Sebastien Muller, co-author of the paper. "Our discovery is a giant leap in terms of observing frequency, thanks to the use of ALMA, and in terms of distance to the black hole where the magnetic field has been probed -- of the order of only a few light-days from the event horizon. These results, and future studies, will help us understand what is really going on in the immediate vicinity of supermassive black holes."

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New technique simultaneously reveals structure and function of proteins critical in DNA repair

New technique simultaneously reveals structure and function of proteins critical in DNA repair | Amazing Science | Scoop.it

By combining two highly innovative experimental techniques, scientists at the University of Illinois at Urbana-Champaign have for the first time simultaneously observed the structure and the correlated function of specific proteins critical in the repair of DNA, providing definitive answers to some highly debated questions, and opening up new avenues of inquiry and exciting new possibilities for biological engineering.


Scientists who study biological systems at the molecular level have over the years looked to the structure of protein molecules—how the atoms are organized—to shed light on the diverse functions each performs in the cell. The inverse is also true: observing the specific work particular protein molecules perform has provided important clues as to the conformation of the respective molecules. But until recently, our most advanced laboratory experiments could only investigate one at a time—static form or dynamic function—and from the results, deduce the other. This indirect method often doesn’t provide definitive answers.


Now Illinois biological physicists Taekjip Ha and Yann Chemla have combined two cutting-edge laboratory techniques that together directly get at the structure-function relationship in proteins. Ha, who co-directs the Center for the Physics of Living Cells at Illinois, is well recognized for his innovative single molecule fluorescence microscopy and spectroscopy techniques. Chemla is a top expert in optical trapping techniques. Their combined method—simultaneous fluorescence microscopy and optical trapping—yields far more definitive answers to questions relating structure to function than either technique could independently.


Working in collaboration, Ha and Chemla each applied the above techniques in their laboratories, with conclusive results. The findings of these experiments have been published in two separate articles in the April 17 issue of the journal Science.

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Tiniest circuits: Light-controlled molecule switching for single-molecule information processing and storing

Tiniest circuits: Light-controlled molecule switching for single-molecule information processing and storing | Amazing Science | Scoop.it

Scientists at the University of Konstanz and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) are working on storing and processing information on the level of single molecules to create the smallest possible components that will combine autonomously to form a circuit. As recently reported in the academic journal Advanced Science, the researchers can switch on the current flow through a single molecule for the first time with the help of light.


Dr. Artur Erbe, physicist at the HZDR, is convinced that in the future molecular electronics will open the door for novel and increasingly smaller -- while also more energy efficient -- components or sensors: "Single molecules are currently the smallest imaginable components capable of being integrated into a processor." Scientists have yet to succeed in tailoring a molecule so that it can conduct an electrical current and that this current can be selectively turned on and off like an electrical switch.


This requires a molecule in which an otherwise strong bond between individual atoms dissolves in one location -- and forms again precisely when energy is pumped into the structure. Dr. Jannic Wolf, chemist at the University of Konstanz, discovered through complex experiments that a particular diarylethene compound is an eligible candidate. The advantages of this molecule, approximately three nanometres in size, are that it rotates very little when a point in its structure opens and it possesses two nanowires that can be used as contacts. The diarylethene is an insulator when open and becomes a conductor when closed. It thus exhibits a different physical behaviour, a behaviour that the scientists from Konstanz and Dresden were able to demonstrate with certainty in numerous reproducible measurements for the first time in a single molecule.


A special feature of these molecular electronics is that they take place in a fluid within a test-tube, where the molecules are contacted within the solution. In order to ascertain what effects the solution conditions have on the switching process, it was therefore necessary to systematically test various solvents. The diarylethene needs to be attached at the end of the nanowires to electrodes so that the current can flow. "We developed a nanotechnology at the HZDR that relies on extremely thin tips made of very few gold atoms. We stretch the switchable diarylethene compound between them," explains Dr. Erbe.


When a beam of light then hits the molecule, it switches from its open to its closed state, resulting in a flowing current. "For the first time ever we could switch on a single contacted molecule and prove that this precise molecule becomes a conductor on which we have used the light beam," says Dr. Erbe, pleased with the results. "We have also characterized the molecular switching mechanism in extremely high detail, which is why I believe that we have succeeded in making an important step toward a genuine molecular electronic component."


Switching off, however, does not yet work with the contacted diarylethene, but the physicist is confident: "Our colleagues from the HZDR theory group are computing how precisely the molecule must rotate so that the current is interrupted. Together with the chemists from Konstanz, we will be able to accordingly implement the design and synthesis for the molecule." However, a great deal of patience is required because it's a matter of basic research. The diarylethene molecule contact using electron-beam lithography and the subsequent measurements alone lasted three long years.


Approximately ten years ago, a working group at the University of Groningen in the Netherlands had already managed to construct a switch that could interrupt the current. The off-switch also worked only in one direction, but what couldn't be proven at the time with certainty was that the change in conductivity was bound to a single molecule.


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How malaria is evolving to survive our most potent drug, artemisin

How malaria is evolving to survive our most potent drug, artemisin | Amazing Science | Scoop.it

Bacterial pathogens aren't the only ones that can evolve to evade the drugs we throw at them. In southeast Asia, Plasmodium falciparum, the parasite that causes malaria, has begun to develop resistance to a drug called artemisin.


Artemisin has been the front-line drug used against malaria since the 1990s, when malaria became resistant to the previous drugs used to combat it. Currently, no real alternatives exist. Combating malaria is a pretty serious priority, as it kills a child a minute in Africa. If we lose our most potent weapon against it, that combat will become much more difficult. Artemisin's name comes from its source, sweet wormwood—Artemisia annua—which is related, but not identical, to the wormwood used to make absinthe, Artemisia absinthium.


Understanding resistance is challenging because it is not really clear how artemisin works—which parasitic proteins or processes it disrupts. While genome-wide association studies have identified mutations in resistant strains of the parasite, it has been difficult to figure out how these mutations might interfere with the drug. New work has now shown how these mutations are able to cause resistance; results are reported in Nature.


Artemisin binds to and thereby blocks the activity of a parasitic enzyme called PfPI3K, so you'd expect that to be critical. But no mutations were found in PfPI3K in any artemisin-resistant strains of malaria. Instead, the most prevalent mutation in resistant populations was in a protein called PfKelch13. Currently, we don't know the function of this protein, just that it does not interact with artemisin.


The mammalian protein that is most similar to PfKelch13 is involved in protein degradation, so the researchers thought that PfKelch13 might be as well. They were right. PfKelch13 plays a role in delivering artemisin's target, PfPI3K, to the cellular protein degradation machinery. The mutations in PfKelch13 that cause artemisin resistance do so by preventing it from degrading artemisin's target, PfPI3K.


As a result, resistant strains have about twice as much PfPI3K in them than sensitive strains do; artemisin can't inhibit all of that extra enzyme. This twofold increase in PfPI3K levels was able to increase resistance by a factor of 10, though, suggesting that its effects are amplified by its downstream targets.

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Dark Matter More Complex Than Thought: First Signs of Self-interacting Dark Matter?

Dark Matter More Complex Than Thought: First Signs of Self-interacting Dark Matter? | Amazing Science | Scoop.it

For the first time dark matter may have been observed interacting with other dark matter in a way other than through the force of gravity. Observations of colliding galaxies made with ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope have picked up the first intriguing hints about the nature of this mysterious component of the Universe.


Using the MUSE instrument on ESO’s VLT in Chile, along with images from Hubble in orbit, a team of astronomers studied the simultaneous collision of four galaxies in the galaxy cluster Abell 3827. The team could trace out where the mass lies within the system and compare the distribution of the dark matter with the positions of the luminous galaxies.


Although dark matter cannot be seen, the team could deduce its location using a technique called gravitational lensing. The collision happened to take place directly in front of a much more distant, unrelated source. The mass of dark matter around the colliding galaxies severely distorted spacetime, deviating the path of light rays coming from the distant background galaxy — and distorting its image into characteristic arc shapes.


Our current understanding is that all galaxies exist inside clumps of dark matter. Without the constraining effect of dark matter’s gravity, galaxies like the Milky Way would fling themselves apart as they rotate. In order to prevent this, 85 percent of the Universe’s mass [1] must exist as dark matter, and yet its true nature remains a mystery.


In this study, the researchers observed the four colliding galaxies and found that one dark matter clump appeared to be lagging behind the galaxy it surrounds. The dark matter is currently 5000 light-years (50 000 million million kilometres) behind the galaxy — it would take NASA’s Voyager spacecraft 90 million years to travel that far.


A lag between dark matter and its associated galaxy is predicted during collisions if dark matter interacts with itself, even very slightly, through forces other than gravity [2]. Dark matter has never before been observed interacting in any way other than through the force of gravity.


Lead author Richard Massey at Durham University, explains: “We used to think that dark matter just sits around, minding its own business, except for its gravitational pull. But if dark matter were being slowed down during this collision, it could be the first evidence for rich physics in the dark sector — the hidden Universe all around us.

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Wild chimps look both ways before crossing roads

Wild chimps look both ways before crossing roads | Amazing Science | Scoop.it

In a 29-month survey, researchers observed and recorded 20 instances of wild chimps crossing a busy road in Sebitoli, in the northern part of Uganda's Kibale National Park. They watched 122 chimps cross the highway used by 90 vehicles an hour, many speeding at 70 to 100 kilometres an hour. It's the first report on how chimpanzees behave crossing a very busy asphalt road, says Marie Cibot of the National Museum of Natural History in Paris. "We've described chimpanzee behaviour facing a dangerous situation never described before," she says, pointing out that earlier studies looked at narrower, unpaved and less busy roads.


Chimps are exceptionally cautious when they cross the road. Ninety-two per cent of them looked right, left, or both ways before or during crossing, and 57 per cent ran across – showing that they knew the value of reaching the other side as quickly as possible.


Alpha males led and organised 83 per cent of the road-crossing posses, compared with only 51 per cent of tree-climbing expeditions in the forest studied in parallel. This implies that they recognised the importance of extra vigilance during road crossings.


There was also evidence that healthy and dominant chimps often made sure that stragglers or more vulnerable members of the group crossed safely. Some 86 per cent of the healthy chimps looked back or stopped when at least one vulnerable individual, such as an infant or injured chimp, trailed behind.


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Nanotubes self-organize and wiggle: Evolution of a non-equilibrium system shows maximum entropy production

Nanotubes self-organize and wiggle: Evolution of a non-equilibrium system shows maximum entropy production | Amazing Science | Scoop.it

Physicists Alexey BezryadinAlfred Hubler, and Andrey Belkin from the University of Illinois at Urbana-Champaign, have demonstrated the emergence of self-organized structures that drive the evolution of a non-equilibrium system to a state of maximum entropy production. The authors suggest MEPP underlies the evolution of the artificial system’s self-organization, in the same way that it underlies the evolution of ordered systems (biological life) on Earth. The team’s results are published in Nature Publishing Group’s online journal Scientific Reports.


MEPP may have profound implications for our understanding of the evolution of biological life on Earth and of the underlying rules that govern the behavior and evolution of all nonequilibrium systems. Life emerged on Earth from the strongly nonequilibrium energy distribution created by the Sun’s hot photons striking a cooler planet. Plants evolved to capture high energy photons and produce heat, generating entropy. Then animals evolved to eat plants increasing the dissipation of heat energy and maximizing entropy production.


In their experiment, the researchers suspended a large number of carbon nanotubes in a non-conducting non-polar fluid and drove the system out of equilibrium by applying a strong electric field. Once electrically charged, the system evolved toward maximum entropy through two distinct intermediate states, with the spontaneous emergence of self-assembled conducting nanotube chains.


In the first state, the “avalanche” regime, the conductive chains aligned themselves according to the polarity of the applied voltage, allowing the system to carry current and thus to dissipate heat and produce entropy. The chains appeared to sprout appendages as nanotubes aligned themselves so as to adjoin adjacent parallel chains, effectively increasing entropy production. But frequently, this self-organization was destroyed through avalanches triggered by the heating and charging that emanates from the emerging electric current streams. (Watch the video.)


“The avalanches were apparent in the changes of the electric current over time,” said Bezryadin.

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3-D human skin map shows relationship between skin, chemicals, microbes and environment

3-D human skin map shows relationship between skin, chemicals, microbes and environment | Amazing Science | Scoop.it

Researchers at the University of California, San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences used information collected from hundreds of skin swabs to produce three-dimensional maps of molecular and microbial variations across the body. These maps provide a baseline for future studies of the interplay between the molecules that make up our skin, the microbes that live on us, our personal hygiene routines and other environmental factors. The study, published March 30 by Proceedings of the National Academy of Sciences, may help further our understanding of the skin's role in human health and disease.


"This is the first study of its kind to characterize the surface distribution of skin molecules and pair that data withmicrobial diversity," said senior author Pieter Dorrestein, PhD, professor of pharmacology in the UC San Diego Skaggs School of Pharmacy. "Previous studies were limited to select areas of the skin, rather than the whole body, and examined skin chemistry and microbial populations separately."

To sample human skin nearly in its entirety, Dorrestein and team swabbed 400 different body sites of two healthy adult volunteers, one male and one female, who had not bathed, shampooed or moisturized for three days. They used a technique called mass spectrometry to determine the molecular and chemical composition of the samples. They also sequenced microbial DNA in the samples to identify the bacterial species present and map their locations across the body. The team then used MATLAB software to construct 3D models that illustrated the data for each sampling spot.

Despite the three-day moratorium on personal hygiene products, the most abundant molecular features in the skin swabs still came from hygiene and beauty products, such as sunscreen. According to the researchers, this finding suggests that 3D skin maps may be able to detect both current and past behaviors and environmental exposures. The study also demonstrates that human skin is not just made up of molecules derived from human or bacterial cells. Rather, the external environment, such as plastics found in clothing, diet, hygiene and beauty products, also contribute to the skin's chemical composition.

The maps now allow these factors to be taken into account and correlated with local microbial communities.
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The First Ever Real Time Video of a Cracking Joint

The First Ever Real Time Video of a Cracking Joint | Amazing Science | Scoop.it

Scientists based out of the University of Alberta have -- for the first time -- imaged a joint cracking in real time, effectively putting to rest a decades-long debate in the process. They revealed their success in the journal PLoS ONEDoubtless you've experienced the physiological wonder that is a cracking knuckle. The audible pop it makes can sometimes be heard across an entire room, making many bystanders wince. But they probably have nothing to cringe about. While joint cracking may sound painful, it's not associated with any adverse health effects -- arthritis, for example.


Everyone knows that bending or stretching a joint is what causes it to crack, but what's going on under the skin? First off, a joint is where two bones meet. At the ends of each bone is soft, cushioning cartilage. Connecting the cartilage -- and thus the bones -- is a synovial membrane that's filled with a thick, lubricating fluid. Bending the joint can cause the membrane to stretch, which in turn causes the pressure inside it to drop and a bubble of dissolved gas to form within the fluid. The whole process is called tribonucleation.


“It’s a little bit like forming a vacuum,” says Professor Greg Kawchuk, the lead researcher. “As the joint surfaces suddenly separate, there is no more fluid available to fill the increasing joint volume, so a cavity is created...” For decades, prevailing wisdom has held that the popping noise is tied to these bubbles, but scientists have debated whether the sound is caused by the bubble's formation or its collapse. Thanks to Kawchuk and his team, we now know it's the former. When they watched a volunteer's knuckles crack inside an MRI machine in real time, the pop clearly occurred when the bubble formed. Moreover, the bubble persisted well after the sound was heard

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‘Spin-orbitronics’ could ‘revolutionize the electronics industry’ by manipulating magnetic domains

‘Spin-orbitronics’ could ‘revolutionize the electronics industry’ by manipulating magnetic domains | Amazing Science | Scoop.it

Researchers at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have found a new way of manipulating the walls that define magnetic domains (uniform areas in magnetic materials) and the results could one day revolutionize the electronics industry, they say. Gong Chen and Andreas Schmid, experts in electron microscopy with Berkeley Lab’s Materials Sciences Division, led the discovery of a technique by which the “spin textures” of magnetic domain walls in ultrathin magnets can be switched between left-handed, right-handed, cycloidal, helical and mixed structures.


The “handedness” or “chirality” of spin texture determines the movement of a magnetic domain wall in response to an electric current, so this technique, which involves the strategic application of uniaxial strain, should lend itself to the creation of domains walls designed for desired electronic memory and logic functions.


“The information sloshing around today’s Internet is essentially a cacophony of magnetic domain walls being pushed around within the magnetic films of memory devices,” says Schmid. “Writing and reading information today involves mechanical processes that limit reliability and speed. Our findings pave the way to use the spin-orbit forces that act upon electrons in a current to propel magnetic domain walls either in the same direction as the current, or in the opposite direction, or even sideways, opening up a rich new smorgasbord of possibilities in the field of spin-orbitronics.”


The study was carried out at at the National Center for Electron Microscopy (NCEM), which is part of the Molecular Foundry, a DOE Office of Science User Facility. The results have been reported in a Nature Communications paper titled “Unlocking Bloch-type chirality in ultrathin magnets through uniaxial strain.”


In addition to carrying a negative electrical charge, electrons also carry a quantum mechanical property known as “spin,” which arises from tiny magnetic fields created by their rotational momentum. For the sake of simplicity, spin is assigned a direction of either “up” or “down.” Because of these two properties, a flow of electrons creates both charge and spin currents. Charge currents are well understood and serve as the basis for today’s electronic devices. Spin currents are just beginning to be explored as the basis for the emerging new field of spintronics. Coupling the flows of charge and spin currents together opens the door to yet another new field in electronics called “spin-orbitronics.” The promise of spin-orbitronics is smaller, faster and far more energy efficient devices through solid-state magnetic memory.


The key to coupling charge and spin currents lies within magnetic domains, regions in a magnetic material in which all of the spins of the electrons are aligned with one another and point in the same direction – up or down. In a magnetic material containing multiple magnetic domains, individual domains are separated from one another by narrow zones or “walls” that feature rapidly changing spin directions.


Applying a technique called “SPLEEM,” for Spin-Polarized Low Energy Electron Microscopy, to a thin-film of iron/nickel bilayers on tungsten, Chen and Schmid and their collaborators were able to stabilize domain walls that were a mixture of Bloch and Neel types. They also showed how the chirality of domain walls can be switched between left-and right-handedness. This was accomplished by controlling uniaxial strain on the thin films in the presence of an asymmetric magnetic exchange interaction between neighboring electron spins.


“Depending on their handedness, Neel-type walls are propelled with or against the current direction, while Bloch-type walls are propelled to the left or to the right across the current,” Chen says. “Our findings introduce Bloch-type chirality as a new spin texture and might allow us to tailor the spin structure of chiral domain walls. This would present new opportunities to design spin–orbitronic devices.”


“Magnetization is a 3D vector, not just a scalar property and in order to see spin textures, the three Cartesian components of the magnetization must be resolved,” Schmid says. “Berkeley Lab’s SPLEEM instrument is one of a mere handful of instruments worldwide that permit imaging all three Cartesian components of magnetization. It was the unique SPLEEM experimental capability that made this spin-orbitronics research possible.”

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