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  • richardmitnick 1:07 pm on December 3, 2018 Permalink | Reply
    Tags: , , , , MESO devices, , Multiferroics, UC Berkeley   

    From UC Berkeley: “New quantum materials could take computing devices beyond the semiconductor era” 

    UC Berkeley

    From UC Berkeley

    December 3, 2018
    Robert Sanders
    rlsanders@berkeley.edu

    1
    MESO devices, based on magnetoelectric and spin-orbit materials, could someday replace the ubiquitous semiconductor transistor, today represented by CMOS. MESO uses up-and-down magnetic spins in a multiferroic material to store binary information and conduct logic operations. (Intel graphic)

    Researchers from Intel Corp. and UC Berkeley are looking beyond current transistor technology and preparing the way for a new type of memory and logic circuit that could someday be in every computer on the planet.

    In a paper appearing online Dec. 3 in advance of publication in the journal Nature, the researchers propose a way to turn relatively new types of materials, multiferroics and topological materials, into logic and memory devices that will be 10 to 100 times more energy-efficient than foreseeable improvements to current microprocessors, which are based on CMOS (complementary metal–oxide–semiconductor).

    The magneto-electric spin-orbit or MESO devices will also pack five times more logic operations into the same space than CMOS, continuing the trend toward more computations per unit area, a central tenet of Moore’s Law.

    The new devices will boost technologies that require intense computing power with low energy use, specifically highly automated, self-driving cars and drones, both of which require ever increasing numbers of computer operations per second.

    “As CMOS develops into its maturity, we will basically have very powerful technology options that see us through. In some ways, this could continue computing improvements for another whole generation of people,” said lead author Sasikanth Manipatruni, who leads hardware development for the MESO project at Intel’s Components Research group in Hillsboro, Oregon. MESO was invented by Intel scientists, and Manipatruni designed the first MESO device.

    Transistor technology, invented 70 years ago, is used today in everything from cellphones and appliances to cars and supercomputers. Transistors shuffle electrons around inside a semiconductor and store them as binary bits 0 and 1.

    2
    Single crystals of the multiferroic material bismuth-iron-oxide. The bismuth atoms (blue) form a cubic lattice with oxygen atoms (yellow) at each face of the cube and an iron atom (gray) near the center. The somewhat off-center iron interacts with the oxygen to form an electric dipole (P), which is coupled to the magnetic spins of the atoms (M) so that flipping the dipole with an electric field (E) also flips the magnetic moment. The collective magnetic spins of the atoms in the material encode the binary bits 0 and 1, and allow for information storage and logic operations.

    In the new MESO devices, the binary bits are the up-and-down magnetic spin states in a multiferroic, a material first created in 2001 by Ramamoorthy Ramesh, a UC Berkeley professor of materials science and engineering and of physics and a senior author of the paper.

    “The discovery was that there are materials where you can apply a voltage and change the magnetic order of the multiferroic,” said Ramesh, who is also a faculty scientist at Lawrence Berkeley National Laboratory. “But to me, ‘What would we do with these multiferroics?’ was always a big question. MESO bridges that gap and provides one pathway for computing to evolve”

    In the Nature paper, the researchers report that they have reduced the voltage needed for multiferroic magneto-electric switching from 3 volts to 500 millivolts, and predict that it should be possible to reduce this to 100 millivolts: one-fifth to one-tenth that required by CMOS transistors in use today. Lower voltage means lower energy use: the total energy to switch a bit from 1 to 0 would be one-tenth to one-thirtieth of the energy required by CMOS.

    “A number of critical techniques need to be developed to allow these new types of computing devices and architectures,” said Manipatruni, who combined the functions of magneto-electrics and spin-orbit materials to propose MESO. “We are trying to trigger a wave of innovation in industry and academia on what the next transistor-like option should look like.”

    Internet of things and AI

    The need for more energy-efficient computers is urgent. The Department of Energy projects that, with the computer chip industry expected to expand to several trillion dollars in the next few decades, energy use by computers could skyrocket from 3 percent of all U.S. energy consumption today to 20 percent, nearly as much as today’s transportation sector. Without more energy-efficient transistors, the incorporation of computers into everything – the so-called internet of things – would be hampered. And without new science and technology, Ramesh said, America’s lead in making computer chips could be upstaged by semiconductor manufacturers in other countries.

    “Because of machine learning, artificial intelligence and IOT, the future home, the future car, the future manufacturing capability is going to look very different,” said Ramesh, who until recently was the associate director for Energy Technologies at Berkeley Lab. “If we use existing technologies and make no more discoveries, the energy consumption is going to be large. We need new science-based breakthroughs.”

    Paper co-author Ian Young, a UC Berkeley Ph.D., started a group at Intel eight years ago, along with Manipatruni and Dmitri Nikonov, to investigate alternatives to transistors, and five years ago they began focusing on multiferroics and spin-orbit materials, so-called “topological” materials with unique quantum properties.

    “Our analysis brought us to this type of material, magneto-electrics, and all roads led to Ramesh,” said Manipatruni.

    Multiferroics and spin-orbit materials

    Multiferroics are materials whose atoms exhibit more than one “collective state.” In ferromagnets, for example, the magnetic moments of all the iron atoms in the material are aligned to generate a permanent magnet. In ferroelectric materials, on the other hand, the positive and negative charges of atoms are offset, creating electric dipoles that align throughout the material and create a permanent electric moment.

    MESO is based on a multiferroic material consisting of bismuth, iron and oxygen (BiFeO3) that is both magnetic and ferroelectric. Its key advantage, Ramesh said, is that these two states – magnetic and ferroelectric – are linked or coupled, so that changing one affects the other. By manipulating the electric field, you can change the magnetic state, which is critical to MESO.

    The key breakthrough came with the rapid development of topological materials with spin-orbit effect, which allow for the state of the multiferroic to be read out efficiently. In MESO devices, an electric field alters or flips the dipole electric field throughout the material, which alters or flips the electron spins that generate the magnetic field. This capability comes from spin-orbit coupling, a quantum effect in materials, which produces a current determined by electron spin direction.

    In another paper that appeared earlier this month in Science Advances, UC Berkeley and Intel experimentally demonstrated voltage-controlled magnetic switching using the magneto-electric material bismuth-iron-oxide (BiFeO3), a key requirement for MESO.

    “We are looking for revolutionary and not evolutionary approaches for computing in the beyond-CMOS era,” Young said. “MESO is built around low-voltage interconnects and low-voltage magneto-electrics, and brings innovation in quantum materials to computing.”

    Other co-authors of the Nature paper are Chia-Ching Lin, Tanay Gosavi and Huichu Liu of Intel and Bhagwati Prasad, Yen-Lin Huang and Everton Bonturim of UC Berkeley. The work was supported by Intel.

    RELATED INFORMATION

    Beyond CMOS computing with spin and polarization Nature Physics

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Founded in the wake of the gold rush by leaders of the newly established 31st state, the University of California’s flagship campus at Berkeley has become one of the preeminent universities in the world. Its early guiding lights, charged with providing education (both “practical” and “classical”) for the state’s people, gradually established a distinguished faculty (with 22 Nobel laureates to date), a stellar research library, and more than 350 academic programs.

    UC Berkeley Seal

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  • richardmitnick 8:33 am on November 25, 2018 Permalink | Reply
    Tags: A magnetic field is helpful in protecting a planetary atmosphere from being blown away by the stellar winds, , , Earth and planetary science, Earth Might Have Once Had a Different Kind of Magnetic Field-one generated by oceans of magma on its surface instead of the rotation of its core, Electrochemistry of moving magma, , UC Berkeley   

    From UC Berkeley via Science Alert: “Earth Might Have Once Had a Different Kind of Magnetic Field, And It’s Good News For Life on Other Planets” 

    UC Berkeley

    From UC Berkeley

    1
    (dottedhippo/iStock)

    23 NOV 2018
    MIKE MCRAE

    A new study suggests that Earth might have once had a different kind of magnetic field – one generated by oceans of magma on its surface, instead of the rotation of its core.

    And that’s good news, because it means more exoplanets than we thought could have a protective magnetic shield sheltering them from the harsh radiation of space, and a chance of hosting life.

    According to the research, long before Earth had a skin, when its molten insides flowed on its outside and its heart was yet to harden, a magnetic cage was already beginning to bloom overhead.

    An analysis of the electrochemistry of moving magma has found sufficiently sized oceans of liquid rock can generate their own magnetic fields, helping us understand not just our own planet’s history, but the chances of life arising on other worlds.

    Two Earth and planetary scientists from UC Berkeley went back to first principles to simulate the surface conditions of young super-Earths – huge rocky worlds with sub-surface pressures and temperatures guaranteed to keep the planets toasty.

    They found the make-up of these molten crusts could give rise to an electrical conductivity large enough to form a planetary dynamo, and it would take a current of rock flowing at a speed of just 1 millimetre per second to manage it.

    “This is the first detailed calculation for higher temperature and pressure conditions, and it finds that the conductivities appear to be a little bit higher, so the fluid motions you would need to make this all work are maybe a little bit less extreme,” says planetary scientist Burkhard Militzer.

    Our own world has a powerful dynamo churning away deep underfoot in the form of a rotating core of liquid iron and nickel swirling amid a gooey soup of lighter minerals and charged particles.

    We should be super thankful for it – without it, we probably wouldn’t be here.

    “A magnetic field is helpful in protecting a planetary atmosphere from being blown away by the stellar winds,” says co-author François Soubiran, now at the École Normale Supérieure in Lyon, France.

    Not only do we need that atmosphere to keep the surface temperature constant and for life-sustaining chemical reactions, it shields the biosphere from lethal doses of radiation.

    Magnetic fields also do a pretty good job of forming an umbrella that deflects high energy particles from bombarding the crust. So it’s a safe bet that no magnetic field equals no life.

    Knowing which planets outside of our own Solar System can generate magnetic fields might help us sort those that are likely to be sterile from the handful that just might be worth studying for biology.

    What’s more, categorising the different ways planets create magnetic fields opens the way to studying the geology of a planet without needing to set down on its surface.

    “On Jupiter, it arises from the convection of liquid metallic hydrogen,” says Militzer.

    “On Uranus and Neptune, it is assumed to be generated in the ice layers. Now we have added molten rocks to this diverse list of field-generating materials.”

    Just how a surface dynamo might interact with core processes is still anybody’s guess, especially given we know so little about our planet’s interior.

    “The interaction between the liquid core magnetic field and the magma ocean is not easy to predict, but could result in a significant – or even dominant – dipolar component,” the authors write.

    Ideally, to form a protective bubble, a magnetic field should have a neat dipole shape, as opposed to a mess of loops like a poodle’s haircut.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase

    This could be good news for anybody hoping to include super-Earths in their list of potential alien hotspots.

    Most of these insanely big planets – massive rocky bodies that fall short of Neptune’s girth – tend to be pulled close to their temper-prone stars, where solar eruptions and constant heat would make short work of any atmosphere.

    A sufficient dipole magnetic field would give some of them a fighting chance of holding onto precious air while shielding the surface from a scouring brush of solar activity.

    Unfortunately any close proximity to a star also increases the chances such a world would be tidally locked, making its day and year more or less the same length. The team’s analysis suggests a distinct dipole formation would require a relatively rapid rotation, ruling out those slower-spinning worlds.

    With the number of exoplanets in our library climbing into the thousands, and a number of Earth-like worlds among them, we’re going to need better ways to study them.

    Hunting for hints of magnetic fields from afar could help us prioritise our search for life among the stars.

    This research was published in Nature Communications.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Founded in the wake of the gold rush by leaders of the newly established 31st state, the University of California’s flagship campus at Berkeley has become one of the preeminent universities in the world. Its early guiding lights, charged with providing education (both “practical” and “classical”) for the state’s people, gradually established a distinguished faculty (with 22 Nobel laureates to date), a stellar research library, and more than 350 academic programs.

    UC Berkeley Seal

     
  • richardmitnick 2:07 pm on November 12, 2018 Permalink | Reply
    Tags: A research team has adapted a powerful electron-based imaging technique to obtain an image of atomic-scale structure in a synthetic polymer., Before these high-resolution images the arrangement and variation of the different types of crystal structures was unknown, , Cryogenic electron microscopy, Images of individual atoms in polymers had only been realized in computer simulations and illustrations, , , Peptoids are synthetically produced molecules that mimic biological molecules including chains of amino acids known as peptides, , Researchers achieved resolution of about 2 angstroms which is two-tenths of nanometer (billionth of a meter), Scientists Bring Polymers Into Atomic-Scale Focus, There are still mysteries about polymers at the atomic scale, UC Berkeley   

    From Lawrence Berkeley National Lab and UC Berkeley: “Scientists Bring Polymers Into Atomic-Scale Focus” 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    November 12, 2018
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    1
    This image shows a rendering (gray and pink) of the molecular structure of a peptoid polymer that was studied by a team led by Berkeley Lab and UC Berkeley. The successful imaging of a polymer’s atomic-scale structure could inform new designs for plastics, like those that form the water bottles shown in the background. (Credit: Berkeley Lab, Charles Rondeau/PublicDomainPictures.net)

    From water bottles and food containers to toys and tubing, many modern materials are made of plastics. And while we produce about 110 million tons per year of synthetic polymers like polyethylene and polypropylene worldwide for these plastic products, there are still mysteries about polymers at the atomic scale.

    Because of the difficulty in capturing images of these materials at tiny scales, images of individual atoms in polymers have only been realized in computer simulations and illustrations, for example.

    Now, a research team led by Nitash Balsara, a senior faculty scientist in the Materials Sciences Division at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and professor of chemical and biomolecular engineering at UC Berkeley, has adapted a powerful electron-based imaging technique to obtain an image of atomic-scale structure in a synthetic polymer. The team included researchers from Berkeley Lab and UC Berkeley.

    The research could ultimately inform polymer fabrication methods and lead to new designs for materials and devices that incorporate polymers.

    In their study, published in the American Chemical Society’s Macromolecules journal, the researchers detail the development of a cryogenic electron microscopy imaging technique, aided by computerized simulations and sorting techniques, that identified 35 arrangements of crystal structures in a peptoid polymer sample. Peptoids are synthetically produced molecules that mimic biological molecules, including chains of amino acids known as peptides.

    2
    The simulated atomic-scale structure (top) and the averaged atomic-scale imaging (bottom) of a peptoid polymer sample. The sale bar is 10 angstroms, or 1 billionth of a meter. (Credit: Berkeley Lab, UC Berkeley)

    The sample was robotically synthesized at Berkeley Lab’s Molecular Foundry, a DOE Office of Science User Facility for nanoscience research. Researchers formed sheets of crystallized polymers measuring about 5 nanometers (billionths of a meter) in thickness when dispersed in water.

    “We conducted our experiments on the most perfect polymer molecules we could make,” Balsara said – the peptoid samples in the study were extremely pure compared to typical synthetic polymers.

    The research team created tiny flakes of peptoid nanosheets, froze them to preserve their structure, and then imaged them using an electron beam. An inherent challenge in imaging materials with a soft structure, such as polymers, is that the beam used to capture images also damages the samples.

    The direct cryogenic electron microscopy images, obtained using very few electrons to minimize beam damage, are too blurry to reveal individual atoms. Researchers achieved resolution of about 2 angstroms, which is two-tenths of nanometer (billionth of a meter), or about double the diameter of a hydrogen atom.

    They achieved this by taking over 500,000 blurry images, sorting different motifs into different “bins,” and averaging the images in each bin. The sorting methods they used were based on algorithms developed by the structural biology community to image the atomic structure of proteins.

    “We took advantage of technology that the protein-imaging folks had developed and extended it to human-made, soft materials,” Balsara said. “Only when we sorted them and averaged them did that blurriness become clear.”

    Before these high-resolution images, Balsara said, the arrangement and variation of the different types of crystal structures was unknown.

    “We knew that there were many motifs, but they are all different from each other in ways we didn’t know,” he said. “In fact, even the dominant motif in the peptoid sheet was a surprise.”

    3
    Researchers developed a colorized map (right) to show the distribution of different types of crystal structures (left) that they found in the polymer peptoid sample. The scale bar in the map image is 50 nanometers, or 50 billionths of a meter. (Credit: Berkeley Lab, UC Berkeley)

    Balsara credited Ken Downing, a senior scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging Division who passed away in August, and Xi Jiang, a project scientist in the Materials Sciences Division, for capturing the high-quality images that were central to the study and for developing the algorithms necessary to achieve atomic resolution in the polymer imaging.

    Their expertise in cryogenic electron microscopy was complemented by Ron Zuckermann’s ability to synthesize model peptoids, David Prendergast’s knowledge of molecular dynamics simulations needed to interpret the images, Andrew Minor’s expertise in imaging metals at the atomic scale, and Balsara’s experience in the field of polymer science.

    At the Molecular Foundry, Zuckermann directs the Biological Nanostructures facility, Prendergast directs the Theory facility, and Minor directs the National Center for Electron Microscopy and is also a professor of materials science and engineering at UC Berkeley. Much of the cryo-electron imaging was carried out at UC Berkeley’s Krios microscopy facility.

    Balsara said that his own research into using polymers for batteries and other electrochemical devices could benefit from the research, as seeing the position of polymer atoms could greatly aid in the design of materials for these devices.

    Atomic-scale images of polymers used in everyday life may need more sophisticated, automated filtering mechanisms that rely on machine learning, for example.

    “We should be able to determine the atomic-scale structure of a wide variety of synthetic polymers such as commercial polyethylene and polypropylene, leveraging rapid developments in areas such as artificial intelligence, using this approach,” Balsara said.

    Determining crystal structures can provide vital information for other applications, such as the development of drugs, as different crystal motifs could produce quite different binding properties and therapeutic effects, for example.

    The work was conducted within the Soft Matter Electron Microscopy Program at Berkeley Lab, which is supported by the U.S. Department of Energy’s Office of Science; and by the Bay Area Cryo-EM Consortium.

    See the full article here .

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    Please help promote STEM in your local schools.

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    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a UC Berkeley physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    A U.S. Department of Energy National Laboratory Operated by the University of California.

    University of California Seal

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  • richardmitnick 8:37 am on September 27, 2018 Permalink | Reply
    Tags: , , Biomedical research, CZ Biohub awards $13.7 million for new collaborative health research, , Priscilla Chan, UC Berkeley   

    From UC Berkeley: “CZ Biohub awards $13.7 million for new collaborative health research” 

    UC Berkeley

    From UC Berkeley

    September 26, 2018

    The Chan Zuckerberg Biohub (CZ Biohub), a nonprofit medical research organization, today announced that it is awarding $13.7 million over three years to support cutting-edge biomedical research from seven teams of scientists, physicians and engineers, with faculty members from UC Berkeley, UCSF and Stanford on each team.

    1
    Mark Zuckerberg and Priscilla Chan

    The awards will fund two new programs: the CZ Biohub Microbiome Initiative and the CZ Biohub Intercampus Research Awards.

    “We are thrilled by the extent to which these awards honor and support the notion that our most pressing challenges can only be surmounted by transcending the lines that have too long divided academic disciplines, departments and even institutions,” said UC Berkeley Chancellor Carol Christ. “The awards will also help support our efforts to extend the reach of world-class, fundamental research through initiatives that can speed the translation of discoveries into inventions and services for the benefit of all.”

    “For the first time, these new awards bring together highly talented investigators from all three campuses to collaborate on promising new approaches to major biomedical problems,” said Joe DeRisi, co-president of CZ Biohub. “By drawing on the strengths of all three institutions, we believe these teams will accomplish what is now beyond the reach of individual investigators.”

    Launched as a pilot program earlier this year, the CZ Biohub Microbiome Initiative provides $4 million over three years to carry out research on the community of microbes within the human body that influence many aspects of health, from nutrition and immune function to drug metabolism. The Microbiome Initiative brings together eight leading microbiome experts from all three campuses based on their complementary research interests.

    2
    No image caption or credit

    Assembling the Microbiome Initiative team inspired CZ Biohub to create the Intercampus Research Awards. The new competitive awards program promotes collaborative research by bringing together clinicians, biologists, chemists, data scientists, mathematicians, engineers and bioethicists in teams that each include faculty members from all three campuses. The competition drew applications from 83 teams. CZ Biohub initially planned to support three teams but was inspired to increase the number of awards to six, providing $9.7 million over three years.

    “This new collaborative team-based funding allows investigators across the three campuses to tackle demanding problems to enhance health,” said Steve Quake, co-president of CZ Biohub. “These research teams will shed new light on a diverse and challenging set of questions that will advance our understanding while developing technologies that open fresh avenues of research.”

    “We launched the Biohub to bring together some of the brightest scientific minds in the Bay Area with world-class engineering teams, in order to help accelerate the pace of discovery and make faster progress in the fight against disease,” said Priscilla Chan and Mark Zuckerberg, co-founders of the Chan Zuckerberg Initiative and a pediatrician and founder of Facebook, respectively. “Just two years after its launch, it is incredible to see how the Biohub has helped spark promising new collaborations, tools, and research to enable and empower the entire scientific community.”

    The CZ Biohub is an independent non-profit medical research organization collaborating with Stanford, UC Berkeley and UCSF to harness the power of science, technology and human capacity to cure, prevent or manage all disease during our children’s lifetime. For more information about the CZ Biohub, visit https://czbiohub.org.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Founded in the wake of the gold rush by leaders of the newly established 31st state, the University of California’s flagship campus at Berkeley has become one of the preeminent universities in the world. Its early guiding lights, charged with providing education (both “practical” and “classical”) for the state’s people, gradually established a distinguished faculty (with 22 Nobel laureates to date), a stellar research library, and more than 350 academic programs.

    UC Berkeley Seal

     
  • richardmitnick 6:53 pm on September 11, 2018 Permalink | Reply
    Tags: , , , , , , , , , The notorious repeating fast radio source FRB 121102, UC Berkeley   

    From Breakthrough Listen via Science Alert: “Astronomers Have Detected an Astonishing 72 New Mystery Radio Bursts From Space “ 

    From Breakthrough Listen Project

    via

    ScienceAlert

    Science Alert

    11 SEP 2018
    MICHELLE STARR

    A massive number of new signals have been discovered coming from the notorious repeating fast radio source FRB 121102 – and we can thank artificial intelligence for these findings.

    Researchers at the search for extraterrestrial intelligence (SETI) project Breakthrough Listen applied machine learning to comb through existing data, and found 72 fast radio bursts that had previously been missed.

    Fast radio bursts (FRBs) are among the most mysterious phenomena in the cosmos. They are extremely powerful, generating as much energy as hundreds of millions of Suns. But they are also extremely short, lasting just milliseconds; and most of them only occur once, without warning.

    This means they can’t be predicted; so it’s not like astronomers are able to plan observations. They are only picked up later in data from other radio observations of the sky.

    Except for one source. FRB 121102 is a special individual – because ever since its discovery in 2012, it has been caught bursting again and again, the only FRB source known to behave this way.

    Because we know FRB 121102 to be a repeating source of FRBs, this means we can try to catch it in the act. This is exactly what researchers at Breakthrough Listen did last year. On 26 August 2017, they pointed the Green Bank Telescope in West Virginia at its location for five hours.

    In the 400 terabytes of data from that observation, the researchers discovered 21 FRBs using standard computer algorithms, all from within the first hour. They concluded that the source goes through periods of frenzied activity and quiescence.

    But the powerful new algorithm used to reanalyse that August 26 data suggests that FRB 121102 is a lot more active and possibly complex than originally thought. Researchers trained what is known as a convolutional neural network to look for the signals, then set it loose on the data like a truffle pig.

    It returned triumphant with 72 previously undetected signals, bringing the total number that astronomers have observed from the object to around 300.

    “This work is only the beginning of using these powerful methods to find radio transients,” said astronomer Gerry Zhang of the University of California Berkeley, which runs Breakthrough Listen.

    “We hope our success may inspire other serious endeavours in applying machine learning to radio astronomy.”

    The new result has helped us learn a little more about FRB 121102, putting constraints on the periodicity of the bursts. It suggests that, the researchers said, there’s no pattern to the way we receive them – unless the pattern is shorter than 10 milliseconds.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Listen

    Breakthrough Listen is the largest ever scientific research program aimed at finding evidence of civilizations beyond Earth. The scope and power of the search are on an unprecedented scale:

    The program includes a survey of the 1,000,000 closest stars to Earth. It scans the center of our galaxy and the entire galactic plane. Beyond the Milky Way, it listens for messages from the 100 closest galaxies to ours.

    The instruments used are among the world’s most powerful. They are 50 times more sensitive than existing telescopes dedicated to the search for intelligence.

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    UCSC Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA



    GBO radio telescope, Green Bank, West Virginia, USA

    The radio surveys cover 10 times more of the sky than previous programs. They also cover at least 5 times more of the radio spectrum – and do it 100 times faster. They are sensitive enough to hear a common aircraft radar transmitting to us from any of the 1000 nearest stars.

    We are also carrying out the deepest and broadest ever search for optical laser transmissions. These spectroscopic searches are 1000 times more effective at finding laser signals than ordinary visible light surveys. They could detect a 100 watt laser (the energy of a normal household bulb) from 25 trillion miles away.

    Listen combines these instruments with innovative software and data analysis techniques.

    The initiative will span 10 years and commit a total of $100,000,000.

     
  • richardmitnick 12:43 pm on April 11, 2018 Permalink | Reply
    Tags: , , , , UC Berkeley   

    From U Washington via UC Berkeley: “Start of most sensitive search yet for dark matter axion” 

    U Washington

    University of Washington

    UC Berkeley

    UC Berkeley

    April 9, 2018
    Robert Sanders
    rlsanders@berkeley.edu

    1
    The SQUID-based amplifier, which is about a millimeter square, is supercooled to be sensitive to faint signals from axions, should they convert into a microwave photon in the ADMX detector. Sean O’Kelley image

    Thanks to low-noise superconducting quantum amplifiers invented at UC Berkeley, physicists are now embarking on the most sensitive search yet for axions, one of today’s top candidates for dark matter.

    The Axion Dark Matter Experiment (ADMX) reported results today showing that it is the world’s first and only experiment to have achieved the necessary sensitivity to “hear” the telltale signs of dark matter axions.

    The milestone is the result of more than 30 years of research and development, with the latest piece of the puzzle coming in the form of a quantum device that allows ADMX to listen for axions more closely than any experiment ever built.

    John Clarke, a professor of physics in the graduate school at UC Berkeley and a pioneer in the development of sensitive magnetic detectors called SQUIDs (superconducting quantum interference devices), developed the amplifier two decades ago. ADMX scientists, with Clarke’s input, have now incorporated it into the ADMX detector at the University of Washington, Seattle, and are ready to roll.

    “ADMX is a complicated and quite expensive piece of machinery, so it took a while to build a suitable detector so that they could put the SQUID amplifier on it and demonstrate that it worked as advertised. Which it did,” Clarke said.

    The ADMX team published their results online today in the journal Physical Review Letters.

    “This result signals the start of the true hunt for axions,” said Andrew Sonnenschein at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, the operations manager for ADMX. “If dark matter axions exist within the frequency band we will be probing for the next few years, then it’s only a matter of time before we find them.”

    Dark matter: MACHOs, WIMPs or axions?

    U Washington ADMX cutaway rendering of the ADMX detector

    Dark matter is the missing 84 percent of matter in the universe, and physicists have looked extensively for many possible candidates, most prominently massive compact halo objects, or MACHOs, and weakly interacting massive particles, or WIMPs. Despite decades of searching for MACHOs and WIMPs, scientists have struck out; they can see the effects of dark matter in the universe, in how galaxies and stars within galaxies move, but they can’t see dark matter itself.

    Axions are becoming the favored alternative, in part because their existence would also solve problems with the standard model of particle physics today, including the fact that the neutron should have an electric dipole moment, but doesn’t.

    Like other dark-matter candidates, axions are everywhere but difficult to detect. Because they interact with ordinary matter so rarely, they stream through space, even passing through the Earth, without “touching” ordinary matter. ADMX employs a strong magnetic field and a tuned, reflective box to encourage axions to convert to microwave-frequency photons, and uses the quantum amplifier to “listen” for them. All this is done at the lowest possible temperature to reduce background noise.

    Clarke learned of a key stumbling block for ADMX in 1994, when meeting with physicist Leslie Rosenberg, now a professor at the University of Washington and chief scientist for ADMX, and Karl van Bibber, now chair of UC Berkeley’s Department of Nuclear Engineering. Because the axion signal would be very faint, any detector would have to be very cold and “quiet.” Noise from heat, or thermal radiation, is easy to eliminate by cooling the detector down to 0.1 Kelvin, or roughly 460 degrees below zero Fahrenheit. But eliminating the noise from standard semiconductor transistor amplifiers proved difficult.

    They asked Clarke, would SQUID amplifiers solve this problem?

    Supercold amplifiers lower noise to absolute limit

    Though he had built SQUID amplifiers that worked up to 100 MHz frequencies, none worked at the gigahertz frequencies needed, so he set to work to build one. By 1998, he and his collaborators had solved the problem, thanks in large part to initial funding from the National Science Foundation and subsequent funding from the Department of Energy (DOE) through Lawrence Berkeley National Laboratory. The amplifiers on ADMX were funded by DOE through the University of Washington.


    Listening for dark matter: How ADMX employs cold cavities and SQUID amplifiers to find the elusive axion. Courtesy of University of Washington, Seattle.

    Clarke and his group showed that, cooled to temperatures of tens of milliKelvin above absolute zero, the Microstrip SQUID Amplifier (MSA) could achieve a noise that was quantum limited, that is, limited only by Heisenberg’s Uncertainty Principle.

    “You can’t do better than that,” Clarke said.

    This much quieter technology, combined with the refrigeration unit, reduced the noise by a factor of about 30 at 600 MHz so that a signal from the axion, if there is one, should come through loud and clear. The MSA currently in operation on ADMX was fabricated by Gene Hilton at the National Institute of Standards and Technology in Boulder, Colorado, and tested, calibrated and packaged by Sean O’Kelley, a graduate student in Clarke’s research group at UC Berkeley.

    The ADMX team plans to slowly tune through millions of frequencies in hopes of hearing a clear tone from photons produced by axion decay.

    “This result plants a flag,” said Rosenberg. “It tells the world that we have the sensitivity, and have a very good shot at finding the axion. No new technology is needed. We don’t need a miracle anymore, we just need the time.”

    Clarke noted too that the high-frequency, low-noise quantum SQUID amplifiers he invented for ADMX have since been employed in another hot area of physics, to read out the superconducting quantum bits, or qubits, for quantum computers of the future.

    See the full article here .

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    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.

    So what defines us — the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 8:08 am on April 11, 2018 Permalink | Reply
    Tags: Antihydrogen physics, , , , , UC Berkeley   

    From UC Berkeley: “An Improved Method for Antihydrogen Spectroscopy” Berkeley Physics 

    UC Berkeley

    UC Berkeley

    April 4, 2018

    1
    Professor Jonathan Wurtele, undergraduate students Helia Kamal, Nate Belmore, Carlos Sierra, Stefania Balasiu, Cheyenne Nelson, graduate student Celeste Carruth, and Professor Joel Fajans.No image credit

    Berkeley physicists Joel Fajans and Jonathan Wurtele, along with their students and postdocs, have spent over a decade working on antihydrogen physics as part of the ALPHA Collaboration. The quest for precision antihydrogen spectroscopy was realized in a new paper that just appeared in Nature (Characterization of the 1S–2S transition in antihydrogen, Ahmadi et al.)

    Much of the effort of the Berkeley group has been to invent and develop new plasma physics techniques for synthesizing antihydrogen.

    A recent paper in Physical Review Letters, part of the thesis work of Celeste Carruth, reports an improved method for controlling plasma density and temperature, which in turn enabled a factor-of-ten increase in trapping rates. These increased trapping rates enabled reduced statistical and systematic errors that previously limited ALPHA measurements.

    The future is very promising. Improvements to the infrastructure for antiproton generation at CERN will provide on-demand antiprotons after the upcoming two-year CERN accelerator shutdown.

    Further improvements in antihydrogen synthesis may result from very successful plasma cavity cooling experiments by graduate student Eric Hunter. The work, interesting in their own right as a study of coupled nonlinear oscillators, appeared in Physics of Plasmas (Low magnetic field cooling of lepton plasmas via cyclotron-cavity resonance, E. Hunter et al.)

    The research has benefited from nearly two-dozen undergraduate students who have spent a summer at CERN working on ALPHA and worked here on the related plasma physics.

    CERN ALPHA Antimatter Factory

    See the full article here .

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  • richardmitnick 12:11 pm on February 21, 2018 Permalink | Reply
    Tags: , Some black holes erase your past, UC Berkeley   

    From UC Berkeley: “Some black holes erase your past” 

    UC Berkeley

    UC Berkeley

    FEBRUARY 20, 2018
    Robert Sanders
    rlsanders@berkeley.edu

    In the real world, your past uniquely determines your future. If a physicist knows how the universe starts out, she can calculate its future for all time and all space.

    But a UC Berkeley mathematician has found some types of black holes in which this law breaks down. If someone were to venture into one of these relatively benign black holes, they could survive, but their past would be obliterated and they could have an infinite number of possible futures.


    A reasonably realistic simulation of falling into a black hole shows how space and time are distorted, and how light is blue shifted as you approach the inner or Cauchy horizon, where most physicists think you would be annihilated. However, a UC Berkeley mathematician argues that you could, in fact, survive passage through this horizon. Animation by Andrew Hamilton, based on supercomputer simulation by John Hawley.

    Such claims have been made in the past, and physicists have invoked “strong cosmic censorship” to explain it away. That is, something catastrophic – typically a horrible death – would prevent observers from actually entering a region of spacetime where their future was not uniquely determined. This principle, first proposed 40 years ago by physicist Roger Penrose, keeps sacrosanct an idea – determinism – key to any physical theory. That is, given the past and present, the physical laws of the universe do not allow more than one possible future.

    But, says UC Berkeley postdoctoral fellow Peter Hintz, mathematical calculations show that for some specific types of black holes in a universe like ours, which is expanding at an accelerating rate, it is possible to survive the passage from a deterministic world into a non-deterministic black hole.

    What life would be like in a space where the future was unpredictable is unclear. But the finding does not mean that Einstein’s equations of general relativity, which so far perfectly describe the evolution of the cosmos, are wrong, said Hintz, a Clay Research Fellow.

    “No physicist is going to travel into a black hole and measure it. This is a math question. But from that point of view, this makes Einstein’s equations mathematically more interesting,” he said. “This is a question one can really only study mathematically, but it has physical, almost philosophical implications, which makes it very cool.”

    “This … conclusion corresponds to a severe failure of determinism in general relativity that cannot be taken lightly in view of the importance in modern cosmology” of accelerating expansion, said his colleagues at the University of Lisbon in Portugal, Vitor Cardoso, João Costa and Kyriakos Destounis, and at Utrecht University, Aron Jansen.

    As quoted by Physics World, Gary Horowitz of UC Santa Barbara, who was not involved in the research, said that the study provides “the best evidence I know for a violation of strong cosmic censorship in a theory of gravity and electromagnetism.”

    Hintz and his colleagues published a paper describing these unusual black holes last month in the journal Physical Review Letters.

    Beyond the event horizon

    Black holes are bizarre objects that get their name from the fact that nothing can escape their gravity, not even light. If you venture too close and cross the so-called event horizon, you’ll never escape.
    For small black holes, you’d never survive such a close approach anyway. The tidal forces close to the event horizon are enough to spaghettify anything: that is, stretch it until it’s a string of atoms.

    2
    Passing through the outer or event horizon of a black hole would be uneventful for a massive black hole. Animation by Andrew Hamilton, based on supercomputer simulation by John Hawley.

    But for large black holes, like the supermassive objects at the cores of galaxies like the Milky Way, which weigh tens of millions if not billions of times the mass of a star, crossing the event horizon would be, well, uneventful.

    Because it should be possible to survive the transition from our world to the black hole world, physicists and mathematicians have long wondered what that world would look like, and have turned to Einstein’s equations of general relativity to predict the world inside a black hole. These equations work well until an observer reaches the center or singularity, where in theoretical calculations the curvature of spacetime becomes infinite.

    Even before reaching the center, however, a black hole explorer – who would never be able to communicate what she found to the outside world – could encounter some weird and deadly milestones. Hintz studies a specific type of black hole – a standard, non-rotating black hole with an electrical charge – and such an object has a so-called Cauchy horizon within the event horizon.

    The Cauchy horizon is the spot where determinism breaks down, where the past no longer determines the future. Physicists, including Penrose, have argued that no observer could ever pass through the Cauchy horizon point because they would be annihilated.

    As the argument goes, as an observer approaches the horizon, time slows down, since clocks tick slower in a strong gravitational field. As light, gravitational waves and anything else encountering the black hole fall inevitably toward the Cauchy horizon, an observer also falling inward would eventually see all this energy barreling in at the same time. In effect, all the energy the black hole sees over the lifetime of the universe hits the Cauchy horizon at the same time, blasting into oblivion any observer who gets that far.

    You can’t see forever in an expanding universe

    Hintz realized, however, that this may not apply in an expanding universe that is accelerating, such as our own. Because spacetime is being increasingly pulled apart, much of the distant universe will not affect the black hole at all, since that energy can’t travel faster than the speed of light.

    4
    A spacetime diagram of the gravitational collapse of a charged spherical star to form a charged black hole. An observer traveling across the event horizon will eventually encounter the Cauchy horizon, the boundary of the region of spacetime that can be predicted from the initial data. Hintz and his colleagues found that a region of spacetime, denoted by a question mark, cannot be predicted from the initial data in a universe with accelerating expansion, like our own. This violates the principle of strong cosmic censorship. (Image courtesy of APS/Alan Stonebraker)

    In fact, the energy available to fall into the black hole is only that contained within the observable horizon: the volume of the universe that the black hole can expect to see over the course of its existence. For us, for example, the observable horizon is bigger than the 13.8 billion light years we can see into the past, because it includes everything that we will see forever into the future. The accelerating expansion of the universe will prevent us from seeing beyond a horizon of about 46.5 billion light years.

    In that scenario, the expansion of the universe counteracts the amplification caused by time dilation inside the black hole, and for certain situations, cancels it entirely. In those cases – specifically, smooth, non-rotating black holes with a large electrical charge, so-called Reissner-Nordström-de Sitter black holes – an observer could survive passing through the Cauchy horizon and into a non-deterministic world.

    “There are some exact solutions of Einstein’s equations that are perfectly smooth, with no kinks, no tidal forces going to infinity, where everything is perfectly well behaved up to this Cauchy horizon and beyond,” he said, noting that the passage through the horizon would be painful but brief. “After that, all bets are off; in some cases, such as a Reissner-Nordström-de Sitter black hole, one can avoid the central singularity altogether and live forever in a universe unknown.”

    Admittedly, he said, charged black holes are unlikely to exist, since they’d attract oppositely charged matter until they became neutral. However, the mathematical solutions for charged black holes are used as proxies for what would happen inside rotating black holes, which are probably the norm. Hintz argues that smooth, rotating black holes, called Kerr-Newman-de Sitter black holes, would behave the same way.

    “That is upsetting, the idea that you could set out with an electrically charged star that undergoes collapse to a black hole, and then Alice travels inside this black hole and if the black hole parameters are sufficiently extremal, it could be that she can just cross the Cauchy horizon, survives that and reaches a region of the universe where knowing the complete initial state of the star, she will not be able to say what is going to happen,” Hintz said. “It is no longer uniquely determined by full knowledge of the initial conditions. That is why it’s very troublesome.”

    He discovered these types of black holes by teaming up with Cardoso and his colleagues, who calculated how a black hole rings when struck by gravitational waves, and which of its tones and overtones lasted the longest. In some cases, even the longest surviving frequency decayed fast enough to prevent the amplification from turning the Cauchy horizon into a dead zone.

    Hintz’s paper has already sparked other papers, one of which purports to show that most well-behaved black holes will not violate determinism. But Hintz insists that one instance of violation is one too many.

    “People had been complacent for some 20 years, since the mid ’90s, that strong cosmological censorship is always verified,” he said. “We challenge that point of view.”

    Hintz’s work was supported by the Clay Mathematics Institute and the Miller Institute for Basic Research in Science at UC Berkeley.

    Viewpoint: A Possible Failure of Determinism in General Relativity, Physics

    See the full article here .

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  • richardmitnick 7:06 am on February 1, 2018 Permalink | Reply
    Tags: , STORM-stochastic optical reconstruction microscopy, , UC Berkeley   

    From UC Berkeley: “Super-resolution microscopy reveals fine detail of cellular mesh” 

    UC Berkeley

    UC Berkeley

    January 30, 2018
    Robert Sanders
    rlsanders@berkeley.edu

    One of today’s sharpest imaging tools, super-resolution microscopy, produces sparkling images of what until now has been the blurry interior of cells, detailing not only the cell’s internal organs and skeleton, but also providing insights into cells’ amazing flexibility.

    1
    Super-resolution microscopy reveals the two-dimensional triangular protein meshwork underlying the membrane of the red blood cell. Ke Xu image.

    In the current issue of the journal Cell Reports, Ke Xu and his colleagues at UC Berkeley use the technique to provide a sharp view of the geodesic mesh that supports the outer membrane of a red blood cell, revealing why such cells are sturdy yet flexible enough to squeeze through narrow capillaries as they carry oxygen to our tissues.

    The discovery could eventually help uncover how the malaria parasite hijacks this mesh, called the sub-membrane cytoskeleton, when it invades and eventually destroys red blood cells.

    “People know that the parasite interacts with the cytoskeleton, but how it does it is unclear because there has been no good way to look at the structure,” said Xu, an assistant professor of chemistry. “Now that we have resolved what is really going on in a normal healthy cell, we can ask what changes under infection with parasites and how drugs affect the interaction.”

    Typical human cells have a two-dimensional skeleton that supports the outer membrane and a three-dimensional interior skeleton that supports all the organelles inside and serves as a transportation system throughout the cell.

    Red blood cells, however, have only the membrane supports and no internal scaffolding, so they’re basically a balloon filled with molecules of oxygen-carrying hemoglobin. Because of their simpler structure, red blood cells are ideal for studying the skeleton that supports the membrane in all cells.

    Electron microscope images earlier showed that the sub-membrane cytoskeleton in red blood cells is a triangular mesh of proteins, reminiscent of a geodesic dome. But measurements of the size of the triangular subunits were made by flattening out the domed membrane of a dead and dried-out cell, which distorts the structure.

    STORMing the cytoskeleton

    Xu was a postdoctoral fellow in the Harvard University lab of one of the inventors of super-resolution microscopy, Xiaowei Zhuang, and is an expert on the version called STORM (stochastic optical reconstruction microscopy). Super-resolution microscopy gives about 10 times better resolution than standard light microscopy and works well with wet and live cells.

    2
    Labeling one end of the spectrin molecule with a dye reveals where it connects with the actin protein at the vertices of the triangular mesh. Super-resolution microscopy revealed a 80-nanometer distance between vertices, as well as unsuspected gaps in the mesh – weak points that may allow the red blood cell to reshape itself without breaking.

    Using STORM, Xu, former Berkeley postdoc Leiting Pan and graduate student Rui Yan were able to image the full sub-membrane cytoskeleton of fresh red blood cells and discovered that the triangles of the mesh are about half the size of found in earlier measurements done with electron microscopy: each side is 80 nanometers long, instead of 190 nanometers.

    The distinction is critical: The building blocks of the mesh are a protein called spectrin, which can be stretched to a maximum of about 190 nanometers in length. If the mesh were made of stretched spectrin, it would be rigid, Xu said. But since its normal length is a relaxed 80 nanometers, it acts like a spring.
    “It is more like a spring in its relaxed state, where it has much flexibility under compression or stretching, so that gives red blood cells a lot of elasticity under different physiological conditions, such as squeezing through a narrow capillary,” Yan said.

    At the vertices of the mesh, where five to six spectrin proteins come together, is a different protein: actin. Actin is a standard part of the sub-membrane cytoskeleton and one of the main structural components of the cell.

    Tears in the mesh

    Interestingly, STORM revealed never-before-seen holes in the cytoskeletal mesh that may also be critical to its flexibility.

    “This is a defect in the network, but there might be a reason for it,” said Xu, who is also a Chan Zuckerberg Biohub Investigator. “The cell would want to change structure rapidly as it goes through the capillaries, and having those defects is helpful in reorganizing the shape without breaking the mesh. It can act as a weak point as they try to squeeze through things, they can start to bend around those points.”

    3
    Labeling of the spectrin molecule in the axon of a neuron, showing that they are stretched to their full length of 190 nanometers.

    Xu actually discovered the key structural role of spectrin. While still at Harvard, he used STORM to look at the skeletal structure of neurons, and discovered that actin proteins form precisely spaced rings along the entire length of the axon – which can be as much as a foot long – much like the ribs of a snake. They are separated by exactly 190 nanometers, and when he looked through textbooks for proteins with that length, he came across spectrin. He subsequently used STORM to confirm that in its stretched state, spectrin proteins are the spacers between the rings, keeping them precisely separated.

    “The ringed skeleton makes the axon a very stable but bendable structure,” Xu said, whereas the regular spacing may be key to its electrical conductivity.

    Super-resolution microscopy employs a trick to overcome the diffraction limit of light microscopy, which prevents conventional light microscopes from resolving things smaller than half the size of the wavelength of the light, which for visible light is about 300 nanometers.

    4
    STORM can provide clear images of the interior skeleton of a cell, such as this epithelial cell.

    STORM involves attaching a blinking light source to individual molecules and then isolating each light’s position independently of the others, building up a complete image much like the 1880s artists who developed pointillism, producing images from individual dots of paint.

    Typically chemists attach these flashing sources to all molecules of the same type in a cell, such as all actin molecules, but since only a small percentage of the sources blink on at any one time, it’s possible to pinpoint the exact location of each. Today’s best resolution is about 10 nanometers, Xu said, which is about the size of a single protein or molecule.

    The work was supported by the National Natural Science Foundation of China, a Pew Biomedical Scholars Award and a Packard Fellowship for Science and Engineering. Coauthor and postdoc Wan Li contributed to experimental design and data analysis.

    See the full article here .

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  • richardmitnick 2:20 pm on January 3, 2018 Permalink | Reply
    Tags: A study by UC Berkeley geochemists presents new evidence that high levels of oxygen were not critical to the origin of animals, , , , , UC Berkeley   

    From UC Berkeley: “Which came first: complex life or high atmospheric oxygen?” 

    UC Berkeley

    UC Berkeley

    January 3, 2018
    Robert Sanders
    rlsanders@berkeley.edu

    We and all other animals wouldn’t be here today if our planet didn’t have a lot of oxygen in its atmosphere and oceans. But how crucial were high oxygen levels to the transition from simple, single-celled life forms to the complexity we see today?

    A study by UC Berkeley geochemists presents new evidence that high levels of oxygen were not critical to the origin of animals.

    1
    By measuring the oxidation of iron in pillow basalts from undersea volcanic eruptions, UC Berkeley scientists have more precisely dated the oxygenation of the deep ocean, inferring from that when oxygen levels in the atmosphere rose to current high levels. Credit: National Science Foundation .

    The researchers found that the transition to a world with an oxygenated deep ocean occurred between 540 and 420 million years ago. They attribute this to an increase in atmospheric O2 to levels comparable to the 21 percent oxygen in the atmosphere today.

    This inferred rise comes hundreds of millions of years after the origination of animals, which occurred between 700 and 800 million years ago.

    “The oxygenation of the deep ocean and our interpretation of this as the result of a rise in atmospheric O2 was a pretty late event in the context of Earth history,” said Daniel Stolper, an assistant professor of earth and planetary science at UC Berkeley. “This is significant because it provides new evidence that the origination of early animals, which required O2 for their metabolisms, may have gone on in a world with an atmosphere that had relatively low oxygen levels compared to today.”

    He and postdoctoral fellow Brenhin Keller will report their findings in a paper posted online Jan. 3 in advance of publication in the journal Nature. Keller is also affiliated with the Berkeley Geochronology Center.

    The history of Earth’s oxygen

    Oxygen has played a key role in the history of Earth, not only because of its importance for organisms that breathe oxygen, but because of its tendency to react, often violently, with other compounds to, for example, make iron rust, plants burn and natural gas explode.

    Tracking the concentration of oxygen in the ocean and atmosphere over Earth’s 4.5-billion-year history, however, isn’t easy. For the first 2 billion years, most scientists believe very little oxygen was present in the atmosphere or ocean. But about 2.5-2.3 billion years ago, atmospheric oxygen levels first increased. The geologic effects of this are evident: rocks on land exposed to the atmosphere suddenly began turning red as the iron in them reacted with oxygen to form iron oxides similar to how iron metal rusts.

    Earth scientists have calculated that around this time, atmospheric oxygen levels first exceeded about a hundred thousandth of today’s level (0.001 percent), but remained too low to oxygenate the deep ocean, which stayed largely anoxic.

    By 400 million years ago, fossil charcoal deposits first appear, an indication that atmospheric O2 levels were high enough to support wildfires, which require about 50 to 70 percent of modern oxygen levels, and oxygenate the deep ocean. How atmospheric oxygen levels varied between 2,500 and 400 million years ago is less certain and remains a subject of debate.

    “Filling in the history of atmospheric oxygen levels from about 2.5 billion to 400 million years ago has been of great interest given O2’s central role in numerous geochemical and biological processes. For example, one explanation for why animals show up when they do is because that is about when oxygen levels first approached the high atmospheric concentrations seen today,” Stolper said. “This explanation requires that the two are causally linked such that the change to near-modern atmospheric O2 levels was an environmental driver for the evolution of our oxygen-requiring predecessors.”

    In contrast, some researchers think the two events are largely unrelated. Critical to helping to resolve this debate is pinpointing when atmospheric oxygen levels rose to near modern levels. But past estimates of when this oxygenation occurred range from 800 to 400 million years ago, straddling the period during which animals originated.

    When did oxygen levels change for a second time?

    Stolper and Keller hoped to pinpoint a key milestone in Earth’s history: when oxygen levels became high enough – about 10 to 50 percent of today’s level – to oxygenate the deep ocean. Their approach is based on looking at the oxidation state of iron in igneous rocks formed undersea (referred to as “submarine”) volcanic eruptions, which produce “pillows” and massive flows of basalt as the molten rock extrudes from ocean ridges. Critically, after eruption, seawater circulates through the rocks. Today, these circulating fluids contain oxygen and oxidize the iron in basalts. But in a world with deep-oceans devoid of O2, they expected little change in the oxidation state of iron in the basalts after eruption.


    Eruption of pillow basalts on the ocean floor.

    “Our idea was to study the history of the oxidation state of iron in these basalts and see if we could pinpoint when the iron began to show signs of oxidation and thus when the deep ocean first started to contain appreciable amounts of dissolved O2,” Stolper said.

    To do this, they compiled more than 1,000 published measurements of the oxidation state of iron from ancient submarine basalts. They found that the basaltic iron only becomes significantly oxidized relative to magmatic values between about 540 and 420 million years ago, hundreds of millions of years after the origination of animals. They attribute this change to the rise in atmospheric O2 levels to near modern levels. This finding is consistent with some but not all histories of atmospheric and oceanic O2 concentrations.

    “This work indicates that an increase in atmospheric O2 to levels sufficient to oxygenate the deep ocean and create a world similar to that seen today was not necessary for the emergence of animals,” Stolper said. “Additionally, the submarine basalt record provides a new, quantitative window into the geochemical state of the deep ocean hundreds of millions to billions of years ago.”

    See the full article here .

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    • stewarthoughblog 12:01 am on January 4, 2018 Permalink | Reply

      Interesting finding and conclusion. What appears to be lacking is why they do not consider it pertinent and critical to the model they are proposing that the essential barrier to cosmic radiation that ozone forms based on some minimum level of oxygen in the atmosphere. The survivability of advanced organisms is highly dependent on the ozone layer, so consideration of the timing of their appearance relative to increase of oxygen levels is significant, unlike Stolper’s incoherent proposition that increasing oxygen levels prompted evolutionary changes that produced advanced organisms.

      Like

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