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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.

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  • 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 .

    Please help promote STEM in your local schools.

    STEM Icon

    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

    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 .

    Please help promote STEM in your local schools.

    STEM Icon

    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 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 .

    Please help promote STEM in your local schools.

    STEM Icon

    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.

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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

  • richardmitnick 2:56 pm on December 23, 2017 Permalink | Reply
    Tags: , , , Cosmic Axion Spin-Precession Experiment (CASPEr), , International Linear Collider in Japan, Large Underground Xenon (LUX) dark matter experiment, LBNL LZ project at SURF Lead SD USA, MACHOs, SIMPs, UC Berkeley,   

    From UC Berkeley: “MACHOs are Dead. WIMPs are a No-Show. Say Hello to SIMPs” 

    UC Berkeley

    UC Berkeley

    December 4, 2017
    Robert Sanders
    rlsanders@berkeley.edu

    The intensive, worldwide search for dark matter, the missing mass in the universe, has so far failed to find an abundance of dark, massive stars or scads of strange new weakly interacting particles, but a new candidate is slowly gaining followers and observational support.

    1
    Fundamental structures of a pion (left) and a proposed SIMP (strongly interacting massive particle). Pions are composed of an up quark and a down antiquark, with a gluon (g) holding them together. A SIMP would be composed of a quark and an antiquark held together by an unknown type of gluon (G). (Kavli IPMU graphic)

    Called SIMPs – strongly interacting massive particles – they were proposed three years ago by UC Berkeley theoretical physicist Hitoshi Murayama, a professor of physics and director of the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) in Japan, and former UC Berkeley postdoc Yonit Hochberg, now at Hebrew University in Israel.

    Murayama says that recent observations of a nearby galactic pile-up [Nature] could be evidence for the existence of SIMPs, and he anticipates that future particle physics experiments will discover one of them.

    Murayama discussed his latest theoretical ideas about SIMPs and how the colliding galaxies support the theory in an invited talk Dec. 4 at the 29th Texas Symposium on Relativistic Astrophysics in Cape Town, South Africa.

    Astronomers have calculated that dark matter, while invisible, makes up about 85 percent of the mass of the universe. The solidest evidence for its existence is the motion of stars inside galaxies: Without an unseen blob of dark matter, galaxies would fly apart. In some galaxies, the visible stars are so rare that dark matter makes up 99.9 percent of the mass of the galaxy.

    Theorists first thought that this invisible matter was just normal matter too dim to see: failed stars called brown dwarfs, burned-out stars or black holes. Yet so-called massive compact halo objects – MACHOs – eluded discovery, and earlier this year a survey of the Andromeda galaxy by the Subaru Telescope basically ruled out any significant undiscovered population of black holes.


    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level

    The researchers searched for black holes left over from the very early universe, so-called primordial black holes, by looking for sudden brightenings produced when they pass in front of background stars and act like a weak lens. They found exactly one – too few to contribute significantly to the mass of the galaxy.

    3
    This Hubble Space Telescope image of the galaxy cluster Abell 3827 shows the ongoing collision of four bright galaxies and one faint central galaxy, as well as foreground stars in our Milky Way galaxy and galaxies behind the cluster (Arc B and Lensed image A) that are distorted because of normal and dark matter within the cluster. SIMPs could explain why the dark matter, unseen but detectable because of the lensing, lags behind the normal matter in the collision.

    “That study pretty much eliminated the possibility of MACHOs; I would say it is pretty much gone,” Murayama said.

    WIMPs — weakly interacting massive particles — have fared no better, despite being the focus of researchers’ attention for several decades. They should be relatively large – about 100 times heavier than the proton – and interact so rarely with one another that they are termed “weakly” interacting. They were thought to interact more frequently with normal matter through gravity, helping to attract normal matter into clumps that grow into galaxies and eventually spawn stars.

    SIMPs interact with themselves, but not others.

    SIMPs, like WIMPs and MACHOs, theoretically would have been produced in large quantities early in the history of the universe and since have cooled to the average cosmic temperature. But unlike WIMPs, SIMPs are theorized to interact strongly with themselves via gravity but very weakly with normal matter. One possibility proposed by Murayama is that a SIMP is a new combination of quarks, which are the fundamental components of particles like the proton and neutron, called baryons. Whereas protons and neutrons are composed of three quarks, a SIMP would be more like a pion in containing only two: a quark and an antiquark.

    4
    Conventional WIMP theories predict that dark matter particles rarely interact. Murayama and Hochberg predict that dark matter SIMPs, comprised of a quark and an antiquark, would collide and interact, producing noticeable effects when the dark matter in galaxies collide. (Kavli IPMU graphic)

    The SIMP would be smaller than a WIMP, with a size or cross section like that of an atomic nucleus, which implies there are more of them than there would be WIMPs. Larger numbers would mean that, despite their weak interaction with normal matter – primarily by scattering off of it, as opposed to merging with or decaying into normal matter – they would still leave a fingerprint on normal matter, Murayama said.

    He sees such a fingerprint in four colliding galaxies within the Abell 3827 cluster, where, surprisingly, the dark matter appears to lag behind the visible matter. This could be explained, he said, by interactions between the dark matter in each galaxy that slows down the merger of dark matter but not that of normal matter, basically stars.

    “One way to understand why the dark matter is lagging behind the luminous matter is that the dark matter particles actually have finite size, they scatter against each other, so when they want to move toward the rest of the system they get pushed back,” Murayama said. “This would explain the observation. That is the kind of thing predicted by my theory of dark matter being a bound state of new kind of quarks.”

    SIMPs also overcome a major failing of WIMP theory: the ability to explain the distribution of dark matter in small galaxies.

    5
    Conventional WIMP theories predict a highly peaked distribution, or cusp, of dark matter in a small area in the center of every galaxy. SIMP theory predicts a spread of dark matter in the center, which is more typical of dwarf galaxies. (Kavli IPMU graphic based on NASA, STScI images)

    “There has been this longstanding puzzle: If you look at dwarf galaxies, which are very small with rather few stars, they are really dominated by dark matter. And if you go through numerical simulations of how dark matter clumps together, they always predict that there is a huge concentration towards the center. A cusp,” Murayama said. “But observations seem to suggest that concentration is flatter: a core instead of a cusp. The core/cusp problem has been considered one of the major issues with dark matter that doesn’t interact other than by gravity. But if dark matter has a finite size, like a SIMP, the particles can go ‘clink’ and disperse themselves, and that would actually flatten out the mass profile toward the center. That is another piece of ‘evidence’ for this kind of theoretical idea.”

    Ongoing searches for WIMPs and axions

    Ground-based experiments to look for SIMPs are being planned, mostly at accelerators like the Large Hadron Collider at CERN in Geneva, where physicists are always looking for unknown particles that fit new predictions.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    Another experiment at the planned International Linear Collider in Japan could also be used to look for SIMPs.

    ILC schematic, being planned for the Kitakami highland, in the Iwate prefecture of northern Japan

    As Murayama and his colleagues refine the theory of SIMPs and look for ways to find them, the search for WIMPs continues. The Large Underground Xenon (LUX) dark matter experiment in an underground mine in South Dakota has set stringent limits on what a WIMP can look like, and an upgraded experiment called LZ will push those limits further. Daniel McKinsey, a UC Berkeley professor of physics, is one of the co-spokespersons for this experiment, working closely with Lawrence Berkeley National Laboratory, where Murayama is a faculty senior scientist.

    Lux Dark Matter 2 at SURF, Lead, SD, USA

    LBNL LZ project at SURF, Lead, SD, USA

    Physicists are also seeking other dark matter candidates that are not WIMPs. UC Berkeley faculty are involved in two experiments looking for a hypothetical particle called an axion, which may fit the requirements for dark matter. The Cosmic Axion Spin-Precession Experiment (CASPEr), led by Dmitry Budker, a professor emeritus of physics who is now at the University of Mainz in Germany, and theoretician Surjeet Rajendran, a UC Berkeley professor of physics, is planning to look for perturbations in nuclear spin caused by an axion field. Karl van Bibber, a professor of nuclear engineering, plays a key role in the (ADMX-HF), which seeks to detect axions inside a microwave cavity within a strong magnetic field as they convert to photons.

    ADMX Axion Dark Matter Experiment at the University of Washington

    “Of course we shouldn’t abandon looking for WIMPs,” Murayama said, “but the experimental limits are getting really, really important. Once you get to the level of measurement, where we will be in the near future, even neutrinos end up being the background to the experiment, which is unimaginable.”

    Neutrinos interact so rarely with normal matter that an estimated 100 trillion fly through our bodies every second without our noticing, something that makes them extremely difficult to detect.

    “The community consensus is kind of, we don’t know how far we need to go, but at least we need to get down to this level,” he added. “But because there are definitely no signs of WIMPs appearing, people are starting to think more broadly these days. Let’s stop and think about it again.”

    Murayama’s research is supported by the U.S. Department of Energy, National Science Foundation and Japanese Ministry of Education, Culture, Sports, Science and Technology. Murayama is also collaborating with Eric Kuflik of Hebrew University, Tomer Volansky of Tel Aviv University and Jay Wacker of Quora Inc. in Mountain View, California, and Stanford University.

    See the full article here .

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  • richardmitnick 1:09 pm on December 9, 2017 Permalink | Reply
    Tags: , Atom interferometry, Blackbody radiation, Hot bodies are attractive, Optical tweezers, , UC Berkeley   

    From UC Berkeley: “Hot bodies are attractive” 

    UC Berkeley

    UC Berkeley

    December 8, 2017
    Robert Sanders
    rlsanders@berkeley.edu

    Our physical attraction to hot bodies is real, according to UC Berkeley physicists.

    To be clear, they’re not talking about sexual attraction to a “hot” human body.

    1
    The blackbody attraction between a hot tungsten cylinder and a cesium atom is 20 times stronger than the gravitational attraction between them. (Holger Müller graphic)

    But the researchers have shown that a glowing object actually attracts atoms, contrary to what most people – physicists included – would guess.

    The tiny effect is much like the effect a laser has on an atom in a device called optical tweezers, which are used to trap and study atoms, a discovery that led to the 1997 Nobel Prize in Physics shared by former UC Berkeley professor Steven Chu, now at Stanford, Claude Cohen-Tannoudji and William D. Phillips.

    Until three years ago, when a group of Austrian physicists predicted it, no one thought that regular light, or even just the heat given off by a warm object – the infrared glow you see when looking through night-vision goggles – could affect atoms in the same way.

    UC Berkeley physicists, who are expert at measuring minute forces using atom interferometry, designed an experiment to check it out. When they measured the force exerted by the so-called blackbody radiation from a warm tungsten cylinder on a cesium atom, the prediction was confirmed.

    The attraction is actually 20 times the gravitational attraction between the two objects, but since gravity is the weakest of all the forces, the effect on cesium atoms – or any atom, molecule or larger object – is usually too small to worry about.

    “It’s hard to find a scenario where this force would stand out,” said co-author Victoria Xu, a graduate student in the physics department at UC Berkeley. “It is not clear it makes a significant effect anywhere. Yet.”

    As gravity measurements become more precise, though, effects this small need to be taken into account. The next generation of experiments to detect gravitational waves from space may use lab-bench atom interferometers instead of the kilometer-long interferometers now in operation. Interferometers typically combine two light waves to detect tiny changes in the distance they’ve traveled; atom interferometers combine two matter waves to detect tiny changes in the gravitational field they’ve experienced.

    3
    Thermal images like this record blackbody radiation, essentially the infrared light given off as a body cools. (iStock image)

    For very precise inertial navigation using atom interferometers, this force would also have to be taken into account.

    “This blackbody attraction has an impact wherever forces are measured precisely, including precision measurements of fundamental constants, tests of general relativity, measurements of gravity and so on,” said senior author Holger Müller, an associate professor of physics. Xu, Müller and their UC Berkeley colleagues published their study in the December issue of the journal Nature Physics.

    Optical tweezers

    Optical tweezers work because light is a superposition of magnetic and electric fields – an electromagnetic wave. The electric field in a light beam makes charged particles move. In an atom or a small sphere, this can separate positive charges, like the nucleus, from negative charges, like the electrons. This creates a dipole, allowing the atom or sphere to act like a tiny bar magnet.
    The electric field in the light wave can then move this induced electric dipole around, just as you can use a bar magnet to shove a piece of iron around.

    Using more than one laser beam, scientists can levitate an atom or bead to conduct experiments.

    With weak, incoherent light, like blackbody radiation from a hot object, the effect is much weaker, but still there, Müller’s team found.

    4
    The shiny tungsten cylinder can be seen at top through a window into the vacuum chamber of the atom interferometer The cesium atoms are launched upwards through the circular opening below the cylinder. (Holger Müller photo)

    They measured the effect by placing a dilute gas of cold cesium atoms – cooled to three-millionths of a degree above absolute zero (300 nanoKelvin) – in a vacuum chamber and launching them upward with a quick pulse of laser light.

    Half are given an extra kick up towards an inch-long tungsten cylinder glowing at 185 degrees Celsius (365 degrees Fahrenheit), while the other half remain unkicked. When the two groups of cesium atoms fall and meet again, their matter waves interfere, allowing the researchers to measure the phase shift caused by the tungsten-cesium interaction, and thus calculate the attractive force of the blackbody radiation.

    “People think blackbody radiation is a classic concept in physics – it was a catalyst for starting the quantum mechanical revolution 100 years ago – but there are still cool things to learn about it,” Xu said.

    The research was funded by the David and Lucile Packard Foundation, National Science Foundation (037166), Defense Advanced Research Projects Agency (033504) and National Aeronautics and Space Administration (041060-002, 041542, 039088, 038706, and 036803). Other co-authors are Philipp Haslinger, Matt Jaffe and Osip Schwartz of UC Berkeley, Matthias Sonnleitner of the University of Glasgow, Monika Ritsch-Marte of the Medical University of Innsbruck in Austria and Helmut Ritsch of the University of Innsbruck.

    See the full article here .

    Please help promote STEM in your local schools.

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  • richardmitnick 11:54 am on August 31, 2017 Permalink | Reply
    Tags: Berkeley SETI Research Center, , , , UC Berkeley   

    From UC Berkeley: “Distant galaxy sends out 15 high-energy radio bursts” 

    UC Berkeley

    UC Berkeley

    August 30, 2017
    Robert Sanders
    rlsanders@berkeley.edu

    Breakthrough Listen, an initiative to find signs of intelligent life in the universe, has detected 15 brief but powerful radio pulses emanating from a mysterious and repeating source – FRB 121102 – far across the universe.

    Breakthrough Listen Project

    Fast radio bursts are brief, bright pulses of radio emission from distant but largely unknown sources, and FRB 121102 is the only one known to repeat: more than 150 high-energy bursts have been observed coming from the object, which was identified last year as a dwarf galaxy about 3 billion light years from Earth.

    2
    A sequence of 14 of the 15 detected bursts illustrate their dispersed spectrum and extreme variability. The streaks across the colored energy plot are the bursts appearing at different times and different energies because of dispersion caused by 3 billion years of travel through intergalactic space. In the top frequency spectrum, the dispersion has been removed to show the 300 microsecond pulse spike. Capturing this diverse set of bursts was made possible by the broad bandwidth that can be processed by the Breakthrough Listen backend at the Green Bank Telescope.



    GBO radio telescope, Green Bank, West Virginia, USA

    Possible explanations for the repeating bursts range from outbursts from rotating neutron stars with extremely strong magnetic fields – so-called magnetars – to a more speculative idea: They are directed energy sources, powerful laser bursts used by extraterrestrial civilizations to power spacecraft, akin to Breakthrough Starshot’s plan to use powerful laser pulses to propel nano-spacecraft to our solar system’s nearest star, Proxima Centauri.

    Breakthrough Starshot

    “Bursts from this source have never been seen at this high a frequency,” said Andrew Siemion, director of the Berkeley SETI Research Center and of the Breakthrough Listen program.

    As astronomers around the globe try to understand the mechanism generating fast radio bursts, they have repeatedly turned their radio telescopes on FRB 121102. Siemion and his team alerted the astronomical community to the high-frequency activity via an Astronomer’s Telegram on Monday evening, Aug. 28.

    “As well as confirming that the source is in a newly active state, the high resolution of the data obtained by the Listen instrument will allow measurement of the properties of these mysterious bursts at a higher precision than ever possible before,” said Breakthrough Listen postdoctoral researcher Vishal Gajjar, who discovered the increased activity.

    First detected with the Parkes Telescope in Australia, fast radio bursts have now been seen by several radio telescopes around the world.

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

    FRB 121102 was discovered on Nov. 2, 2012, (hence its name) and in 2015 it was the first fast radio burst seen to repeat, ruling out theories of bursts’ origins that involved the catastrophic destruction of the progenitor, at least in this instance.

    Regardless of FRB 121102’s ultimate source, when the recently detected pulses left their host galaxy, our solar system was less than 2 billion years old, noted Steve Croft, a Breakthrough Listen astronomer at UC Berkeley. Life on Earth consisted only of single-celled organisms; it would be another billion years before even the simplest multi-cellular life began to evolve.

    As part of Breakthrough Listen’s program to observe nearby stars and galaxies for signatures of extraterrestrial technology, the project science team at UC Berkeley added FRB 121102 to its list of targets. In the early hours of Saturday, Aug. 26, Gajjar observed that area of the sky using the Breakthrough Listen backend instrument at the Green Bank Telescope in West Virginia.

    The instrument accumulated 400 terabytes (a million million bytes) of data over a five-hour period, observing across the entire 4 to 8 GHz frequency band. This large dataset was searched for signatures of short pulses from the source over a broad range of frequencies, with a characteristic dispersion, or delay as a function of frequency, caused by the presence of gas in space between Earth and the source. The distinctive shape that the dispersion imposes on the initial pulse is an indicator of the amount of material between us and the source, and hence an indicator of the distance to the host galaxy.

    Analysis by Gajjar and the Breakthrough Listen team revealed 15 new pulses from FRB 121102. The observations show for the first time that fast radio bursts emit at higher frequencies than previously observed, with the brightest emission occurring at around 7 GHz.

    “The extraordinary capabilities of the backend receiver, which is able to record several gigahertz of bandwidth at a time, split into billions of individual channels, enable a new view of the frequency spectrum of FRBs, and should shed additional light on the processes giving rise to FRB emission.” Gajjar said.

    “Whether or not fast radio bursts turn out to be signatures of extraterrestrial technology, Breakthrough Listen is helping to push the frontiers of a new and rapidly growing area of our understanding of the universe around us,” Siemion said.

    See the full article here .
    Previously noted briefly here .

    Please help promote STEM in your local schools.

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    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.

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