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  • richardmitnick 2:05 pm on September 12, 2019 Permalink | Reply
    Tags: A star called S0-2 [Andrea Ghez' UCLA Galactic Center Group pet star], , , , , , UCLA   

    From UCLA Newsroom: “Black hole at the center of our galaxy appears to be getting hungrier” 


    From UCLA Newsroom

    September 11, 2019
    Stuart Wolpert
    UCLA
    310-206-0511
    swolpert@stratcomm.ucla.edu

    UCLA astronomers notice brightest light in 24 years of observations.

    1
    Rendering of a star called S0-2 [Andrea Ghez’, UCLA Galactic Center Group, pet star] orbiting the supermassive black hole at the center of the Milky Way. It did not fall in, but its close approach could be one reason for the black hole’s growing appetite. Nicolle Fuller/National Science Foundation.

    Star S0-2 Andrea Ghez Keck/UCLA Galactic Center Group at SGR A*, the supermassive black hole at the center of the milky way

    The enormous black hole at the center of our galaxy is having an unusually large meal of interstellar gas and dust, and researchers don’t yet understand why.

    “We have never seen anything like this in the 24 years we have studied the supermassive black hole,” said Andrea Ghez, UCLA professor of physics and astronomy and a co-senior author of the research. “It’s usually a pretty quiet, wimpy black hole on a diet. We don’t know what is driving this big feast.”

    A paper about the study, led by the UCLA Galactic Center Group, which Ghez heads, is published today in Astrophysical Journal Letters.

    The researchers analyzed more than 13,000 observations of the black hole from 133 nights since 2003. The images were gathered by the W.M. Keck Observatory in Hawaii and the European Southern Observatory’s Very Large Telescope in Chile.

    Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    The team found that on May 13, the area just outside the black hole’s “point of no return” (so called because once matter enters, it can never escape) was twice as bright as the next-brightest observation.

    They also observed large changes on two other nights this year; all three of those changes were “unprecedented,” Ghez said.

    The brightness the scientists observed is caused by radiation from gas and dust falling into the black hole; the findings prompted them to ask whether this was an extraordinary singular event or a precursor to significantly increased activity.

    “The big question is whether the black hole is entering a new phase — for example if the spigot has been turned up and the rate of gas falling down the black hole ‘drain’ has increased for an extended period — or whether we have just seen the fireworks from a few unusual blobs of gas falling in,” said Mark Morris, UCLA professor of physics and astronomy and the paper’s co-senior author.

    The team has continued to observe the area and will try to settle that question based on what they see from new images.

    “We want to know how black holes grow and affect the evolution of galaxies and the universe,” said Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics. “We want to know why the supermassive hole gets brighter and how it gets brighter.”

    The new findings are based on observations of the black hole — which is called Sagittarius A*, or Sgr A* — during four nights in April and May at the Keck Observatory. The brightness surrounding the black hole always varies somewhat, but the scientists were stunned by the extreme variations in brightness during that timeframe, including their observations on May 13.

    “The first image I saw that night, the black hole was so bright I initially mistook it for the star S0-2, because I had never seen Sagittarius A* that bright,” said UCLA research scientist Tuan Do, the study’s lead author. “But it quickly became clear the source had to be the black hole, which was really exciting.”

    One hypothesis about the increased activity is that when a star called S0-2 made its closest approach to the black hole during the summer 2018, it launched a large quantity of gas that reached the black hole this year.

    Another possibility involves a bizarre object known as G2, which is most likely a pair of binary stars, which made its closest approach to the black hole in 2014. It’s possible the black hole could have stripped off the outer layer of G2, Ghez said, which could help explain the increased brightness just outside the black hole.

    Morris said another possibility is that the brightening corresponds to the demise of large asteroids that have been drawn in to the black hole.

    No danger to Earth

    The black hole is some 26,000 light-years away and poses no danger to our planet. Do said the radiation would have to be 10 billion times as bright as what the astronomers detected to affect life on Earth.

    Astrophysical Journal Letters also published a second article by the researchers, describing speckle holography, the technique that enabled them to extract and use very faint information from 24 years of data they recorded from near the black hole.

    Ghez’s research team reported July 25 in the journal Science the most comprehensive test of Einstein’s iconic general theory of relativity near the black hole. Their conclusion that Einstein’s theory passed the test and is correct, at least for now, was based on their study of S0-2 as it made a complete orbit around the black hole.

    Ghez’s team studies more than 3,000 stars that orbit the supermassive black hole. Since 2004, the scientists have used a powerful technology that Ghez helped pioneer, called adaptive optics, which corrects the distorting effects of the Earth’s atmosphere in real time.

    Keck Adaptive Optics

    But speckle holography enabled the researchers to improve the data from the decade before adaptive optics came into play. Reanalyzing data from those years helped the team conclude that they had not seen that level of brightness near the black hole in 24 years.

    “It was like doing LASIK surgery on our early images,” Ghez said. “We collected the data to answer one question and serendipitously unveiled other exciting scientific discoveries that we didn’t anticipate.”

    Co-authors include Gunther Witzel, a former UCLA research scientist currently at Germany’s Max Planck Institute for Radio Astronomy; Mark Morris, UCLA professor of physics and astronomy; Eric Becklin, UCLA professor emeritus of physics and astronomy; Rainer Schoedel, a researcher at Spain’s Instituto de Astrofısica de Andalucıa; and UCLA graduate students Zhuo Chen and Abhimat Gautam.

    The research is funded by the National Science Foundation, W.M. Keck Foundation, the Gordon and Betty Moore Foundation, the Heising-Simons Foundation, Lauren Leichtman and Arthur Levine, and Howard and Astrid Preston.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 9:42 am on August 21, 2019 Permalink | Reply
    Tags: "Technique could make better membranes for next-generation filtration", , “We have demonstrated a platform that we believe will enable researchers to use their new materials in a large thin asymmetric membrane configuration testable in real-world applications.”, In the T-FLO technique the active layer is cast as a liquid on a sheet of glass or metal and cured to make the active layer solid., , More advanced materials to be used for desalination and other processes., T-FLO, The new membrane was also able to remove organic materials from solvent waste and to separate greenhouse gases., UCLA   

    From UCLA Newsroom: “Technique could make better membranes for next-generation filtration” 


    From UCLA Newsroom

    August 20, 2019
    Writer
    Wayne Lewis

    Media Contact
    Nikki Lin
    310-206-8278
    nlin@cnsi.ucla.edu

    UCLA scientists’ method will allow more advanced materials to be used for desalination and other processes.

    1
    UCLA postdoctoral scholar Brian McVerry and doctoral student Mackenzie Anderson examine an ultra-thin membrane film on a glass plate used in the T-FLO process. Marc Roseboro/UCLA

    Deriving drinkable water from seawater, treating wastewater and conducting kidney dialysis are just a few important processes that use a technology called membrane filtration.

    The key to the process is the membrane filter — a thin, semi-porous film that allows certain substances such as water to pass through while separating out other, unwanted substances. But in the past 30 years, there have been no significant improvements in the materials that make up the key layers of commercially produced membrane filters.

    Now, UCLA researchers have developed a new technique called thin-film liftoff, or T-FLO, for creating membrane filters. The approach could offer a way for manufacturers to produce more effective and energy-efficient membranes using high-performance plastics, metal-organic frameworks and carbon materials. To date, limitations in how filters are fabricated have prevented those materials from being viable in industrial production.

    A study describing the work is published in the journal Nano Letters.

    “There are a lot of materials out there that in the lab can do nice separations, but they’re not scalable,” said Richard Kaner, UCLA’s Dr. Myung Ki Hong Professor of Materials Innovation and the study’s senior author. “With this technique, we can take these materials, make thin films that are scalable, and make them useful.”

    In addition to their potential for improving types of filtration that are performed using current technology, membranes produced using T-FLO could make possible an array of new forms of filtration, said Kaner, who also is a distinguished professor of chemistry and biochemistry, and of materials science and engineering, and a member of the California NanoSystems Institute at UCLA. For example, the technique might one day make it feasible to pull carbon dioxide out of industrial emissions — which would enable the carbon to be converted to fuel or other applications while also reducing pollution.

    Filters like the ones used for desalination are called asymmetric membranes because of their two layers: a thin but dense “active” layer that rejects particles larger than a specific size, and a porous “support” layer that gives the membrane structure and allows it to resist the high pressures used in reverse osmosis and other filtering processes. The first asymmetric membrane for desalination was devised by UCLA engineers in the 1960s.

    Today’s asymmetric membranes are made by casting the active layer onto the support layer, or casting both concurrently. But to manufacture an active layer using more advanced materials, engineers have to use solvents or high heat — both of which damage the support layer or prevent the active layer from adhering.

    In the T-FLO technique, the active layer is cast as a liquid on a sheet of glass or metal and cured to make the active layer solid. Next, a support layer made of epoxy reinforced with fabric is added and the membrane is heated to solidify the epoxy.

    The use of epoxy in the support layer is the innovation that distinguishes the T-FLO technique — it enables the active layer to be created first so that it can be treated with chemicals or high heat without damaging the support layer.

    The membrane then is submerged in water to wash out the chemicals that induce pores in the epoxy and to loosen the membrane from the glass or metal sheet.

    Finally, the membrane is peeled off of the plate with a blade — the “liftoff” that gives the method its name.

    “Researchers around the world have demonstrated many new exciting materials that can separate salts, gases and organic materials more effectively than is done industrially,” said Brian McVerry, a UCLA postdoctoral scholar who invented the T-FLO process and is the study’s co-first author. “However, these materials are often made in relatively thick films that perform the separations too slowly or in small samples that are difficult to scale industrially.

    “We have demonstrated a platform that we believe will enable researchers to use their new materials in a large, thin, asymmetric membrane configuration, testable in real-world applications.”

    The researchers tested a membrane produced using T-FLO for removing salt from water, and it showed promise for solving one of the common problems in desalination, which is that microbes and other organic material can clog the membranes. Although adding chlorine to the water can kill the microbes, the chemical also causes most membranes to break down. In the study, the T-FLO membrane both rejected the salt and resisted the chlorine.

    In other experiments, the new membrane was also able to remove organic materials from solvent waste and to separate greenhouse gases.

    Mackenzie Anderson, a UCLA doctoral student, is co-first author of the study.

    The research was supported by the U.S./China Clean Energy Research Center for Water-Energy Technologies and the National Science Foundation. The project is aligned with UCLA’s Sustainable LA Grand Challenge.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 12:16 pm on July 17, 2019 Permalink | Reply
    Tags: , , Glass technology, , , UCLA   

    From UCLA Newsroom: “UCLA researchers toughen glass using nanoparticles” 


    From UCLA Newsroom

    July 16, 2019
    Matthew Chin

    Process could be useful for applications in manufacturing and architecture.

    1
    An electron microscope image of a new, tougher glass developed at UCLA, showing how nanoparticles (rounded, irregular shapes) deflect a crack and force it to branch out. SciFacturing Lab/UCLA

    UCLA mechanical engineers and materials scientists have developed a process that uses nanoparticles to strengthen the atomic structure of glass. The result is a product that’s at least five times tougher than any glass currently available.

    The process could yield glass that’s useful for industrial applications — in engine components and tools that can withstand high temperatures, for instance — as well as for doors, tables and other architectural and design elements.

    The study was published online in the journal Advanced Materials and will be included in a future print edition. The authors wrote that same approach could also be used for manufacturing tougher ceramics that could be used, for example, in spacecraft components that are better able to withstand extreme heat.

    In materials science, “toughness” measures how much energy a material can absorb — and how much it can deform — without fracturing. While glass and ceramics can be reinforced using external treatments, like chemical coatings, those approaches don’t change the fact that the materials themselves are brittle.

    To solve that issue, the UCLA researchers took a cue from the atomic structure of metals, which can take a pounding and not break.

    “The chemical bonds that hold glass and ceramics together are pretty rigid, while the bonds in metals allow some flexibility,” said Xiaochun Li, the Raytheon Professor of Manufacturing at the UCLA Samueli School of Engineering, and the study’s principal investigator. “In glass and ceramics, when the impact is strong enough, a fracture will propagate quickly through the material in a mostly straight path.

    “When something impacts a metal, its more deformable chemical bonds act as shock absorbers and its atoms move around while still holding the structure together.”

    The researchers hypothesized that by infusing glass with nanoparticles of silicon carbide, a metal-like ceramic, the resulting material would be able to absorb more energy before it would fail. They added the nanoparticles into molten glass at 3,000 degrees Fahrenheit, which helped ensure that the nanoparticles were evenly dispersed.

    Once the material solidified, the embedded nanoparticles could act as roadblocks to potential fractures. When a fracture does occur, the tiny particles force it to branch out into tiny networks, instead of allowing it to take a straight path. That branching out enables the glass to absorb significantly more energy from a fracture before it causes significant damage.

    Sintering, in which a powder is heated under pressure, and then cooled, is the main method used to make glass. It also was the method used in previous experiments by other research groups to disperse nanoparticles in glass or ceramics. But in those experiments, the nanoparticles weren’t spread evenly, and the resulting material had uneven toughness.

    The glass blocks that the UCLA team developed for the experiment were somewhat milky, rather than clear, but Li said the process could be adapted to create clear glass.

    The other authors of the study are Qiang-Guo Jiang, a visiting scholar in Li’s SciFacturing Laboratory; Chezheng Cao and Ting-Chiang Lin, who received their doctorates from UCLA in 2018; and Shanghua Wu, an engineering professor at Guangdong University of Technology, China.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 1:04 pm on June 26, 2019 Permalink | Reply
    Tags: , Atomic electron tomography, , , , Nucleation — capturing how the atoms rearrange at 4D atomic resolution, UCLA   

    From UCLA Newsroom: “Atomic motion is captured in 4D for the first time” 


    From UCLA Newsroom

    June 26, 2019
    Wayne Lewis

    Media Contact

    Nikki Lin
    310-206-8278
    nlin@cnsi.ucla.edu

    1
    The image shows 4D atomic motion captured in an iron-platinum nanoparticle at three different times. Alexander Tokarev

    Everyday transitions from one state of matter to another — such as freezing, melting or evaporation — start with a process called “nucleation,” in which tiny clusters of atoms or molecules (called “nuclei”) begin to coalesce. Nucleation plays a critical role in circumstances as diverse as the formation of clouds and the onset of neurodegenerative disease.

    A UCLA-led team has gained a never-before-seen view of nucleation — capturing how the atoms rearrange at 4D atomic resolution (that is, in three dimensions of space and across time). The findings, published in the journal Nature, differ from predictions based on the classical theory of nucleation that has long appeared in textbooks.

    “This is truly a groundbreaking experiment — we not only locate and identify individual atoms with high precision, but also monitor their motion in 4D for the first time,” said senior author Jianwei “John” Miao, a UCLA professor of physics and astronomy, who is the deputy director of the STROBE National Science Foundation Science and Technology Center and a member of the California NanoSystems Institute at UCLA.

    Research by the team, which includes collaborators from Lawrence Berkeley National Laboratory, University of Colorado at Boulder, University of Buffalo and the University of Nevada, Reno, builds upon a powerful imaging technique previously developed by Miao’s research group. That method, called “atomic electron tomography,” uses a state-of-the-art electron microscope located at Berkeley Lab’s Molecular Foundry, which images a sample using electrons. The sample is rotated, and in much the same way a CAT scan generates a three-dimensional X-ray of the human body, atomic electron tomography creates stunning 3D images of atoms within a material.

    Miao and his colleagues examined an iron-platinum alloy formed into nanoparticles so small that it takes more than 10,000 laid side by side to span the width of a human hair. To investigate nucleation, the scientists heated the nanoparticles to 520 degrees Celsius, or 968 degrees Fahrenheit, and took images after 9 minutes, 16 minutes and 26 minutes. At that temperature, the alloy undergoes a transition between two different solid phases.

    Although the alloy looks the same to the naked eye in both phases, closer inspection shows that the 3D atomic arrangements are different from one another. After heating, the structure changes from a jumbled chemical state to a more ordered one, with alternating layers of iron and platinum atoms. The change in the alloy can be compared to solving a Rubik’s Cube — the jumbled phase has all the colors randomly mixed, while the ordered phase has all the colors aligned.

    In a painstaking process led by co-first authors and UCLA postdoctoral scholars Jihan Zhou and Yongsoo Yang, the team tracked the same 33 nuclei — some as small as 13 atoms — within one nanoparticle.

    “People think it’s difficult to find a needle in a haystack,” Miao said. “How difficult would it be to find the same atom in more than a trillion atoms at three different times?”

    The results were surprising, as they contradict the classical theory of nucleation. That theory holds that nuclei are perfectly round. In the study, by contrast, nuclei formed irregular shapes. The theory also suggests that nuclei have a sharp boundary. Instead, the researchers observed that each nucleus contained a core of atoms that had changed to the new, ordered phase, but that the arrangement became more and more jumbled closer to the surface of the nucleus.

    Classical nucleation theory also states that once a nucleus reaches a specific size, it only grows larger from there. But the process seems to be far more complicated than that: In addition to growing, nuclei in the study shrunk, divided and merged; some dissolved completely.

    “Nucleation is basically an unsolved problem in many fields,” said co-author Peter Ercius, a staff scientist at the Molecular Foundry, a nanoscience facility that offers users leading-edge instrumentation and expertise for collaborative research. “Once you can image something, you can start to think about how to control it.”

    The findings offer direct evidence that classical nucleation theory does not accurately describe phenomena at the atomic level. The discoveries about nucleation may influence research in a wide range of areas, including physics, chemistry, materials science, environmental science and neuroscience.

    “By capturing atomic motion over time, this study opens new avenues for studying a broad range of material, chemical and biological phenomena,” said National Science Foundation program officer Charles Ying, who oversees funding for the STROBE center. “This transformative result required groundbreaking advances in experimentation, data analysis and modeling, an outcome that demanded the broad expertise of the center’s researchers and their collaborators.”

    Other authors were Yao Yang, Dennis Kim, Andrew Yuan and Xuezeng Tian, all of UCLA; Colin Ophus and Andreas Schmid of Berkeley Lab; Fan Sun and Hao Zeng of the University at Buffalo in New York; Michael Nathanson and Hendrik Heinz of the University of Colorado at Boulder; and Qi An of the University of Nevada, Reno.

    The research was primarily supported by the STROBE National Science Foundation Science and Technology Center, and also supported by the U.S. Department of Energy.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 9:38 am on May 29, 2019 Permalink | Reply
    Tags: "Nerve stimulation could provide new treatment option for most common type of stroke", A new nerve stimulation therapy to increase blood flow could help patients with the most common type of stroke up to 24 hours after onset., , , Stroke treatments, UCLA   

    From UCLA Newsroom: “Nerve stimulation could provide new treatment option for most common type of stroke” 


    From UCLA Newsroom

    May 24, 2019
    Sandy Van

    1
    The treatment uses a small neurostimulator electrode that is temporarily implanted through the roof of the mouth. BrainsGate

    Research [The Lancet] led by a UCLA scientist found that a new nerve stimulation therapy to increase blood flow could help patients with the most common type of stroke up to 24 hours after onset.

    A study of 1,000 patients found evidence that the technique, called active nerve cell cluster stimulation, reduced the patients’ degree of disability three months after they suffered an acute cortical ischemic stroke, which affects the surface of the brain.

    Dr. Jeffrey Saver, director of the UCLA Comprehensive Stroke Center, was the co-principal investigator of the study, which was conducted at 73 medical centers in 18 countries.

    “We believe this represents the advent of an entirely new treatment for patients with acute ischemic stroke,” said Saver, who also is senior associate vice chair for clinical research in neurology at the David Geffen School of Medicine at UCLA. The study is published today in The Lancet.

    Unlike the two currently approved therapies for acute stroke, which open blocked arteries by dissolving or removing a clot, the new approach applies electrical stimulation to nerve cells behind the nose, increasing blood flow in the brain by dilating undamaged arteries and bypassing the blockage to treat the threatened region of the brain.

    In previous studies to understand the mechanism by which the treatment would work, scientists found that the nerve cell cluster stimulation not only increases blood flow, but also preserves the blood-brain barrier, which prevents brain swelling. It also improved neurons’ ability to compensate for injury and form new connections.

    In a study subset of 520 people who had major deficits and confirmed injury to the cerebral cortex, 40% of those who did not have the stimulation had favorable outcomes, versus 50% of those who did have the stimulation. Although those results fell just short of statistical significance, when the data are combined with similar findings from an earlier trial, the cumulative statistics indicate that the therapy is effective when administered eight to 24 hours after the onset of a cortical acute ischemic stroke.

    The treatment uses a small neurostimulator electrode that is temporarily implanted through the roof of the mouth. (The implant requires only local anesthesia.) During the study, the electrode actively stimulated the nerve cell cluster four hours a day for five consecutive days.

    The first treatment for ischemic stroke, the clot-dissolving drug alteplase, was approved by the Food and Drug Administration in 1996. When administered soon after onset, the drug, which is also called tPA, can sometimes clear a blocked artery, restore blood flow and avert stroke damage. However, its effectiveness diminishes if treatment is delayed beyond three hours, it does not work for all patients, and some people have conditions that preclude its use.

    More recently, the FDA has approved clot-retrieval devices that are threaded through arteries to capture and remove blockages. Used alone or in conjunction with tPA, those devices have extended treatment time to 24 hours after the onset of stroke in some patients, although earlier treatment is more effective. But the devices require expertise that may be absent outside of major medical centers.

    “Stroke continues to be a major cause of death and disability in the United States and around the world, making it imperative that we develop new, effective treatments to complement existing therapies, including in the extended treatment window,” Saver said.

    The trial found that the new stimulation treatment can be safe and effective for people who are not eligible for clot-dissolving medication, Saver said. Future studies will determine the effectiveness of the new therapy when it is used with clot-dissolving medications and clot-retrieving devices.

    Saver and Dr. Natan Bornstein of Tel Aviv University and the Shaare Zedek Medical Center in Israel, were the study’s co-first authors.

    The research was funded by device manufacturer BrainsGate Ltd. Saver, Bornstein and other authors were paid by BrainsGate for serving on a steering committee that provided guidance on the study’s design and approach.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 7:16 pm on May 22, 2019 Permalink | Reply
    Tags: , , carbon and ice, , , , Most people behave differently when under extreme pressure. Carbon and ice are no different., , UCLA   

    From UCLA Newsroom: “New insights about carbon and ice could clarify inner workings of Earth, other planets” 


    From UCLA Newsroom

    Media Contact

    Stuart Wolpert
    UCLA
    310-206-0511
    swolpert@stratcomm.ucla.edu

    May 22, 2019
    Christopher Crockett

    1
    New simulations suggest that carbon (C) routinely bonded with iron (Fe), silicon (Si) and oxygen (O) deep within the magma ocean that covered Earth when it was young. Natalia Solomatova/École Normale Supérieure de Lyon.

    2
    ORNL super-cold states of water. phys.org

    Most people behave differently when under extreme pressure. Carbon and ice are no different.

    Two new studies show how these key planetary ingredients take on exotic forms that could help researchers better understand the composition of Earth’s core as well as the cores of planets across the galaxy. Craig Manning, a UCLA professor of geology and geochemistry, is a co-senior author of one of the papers, which was published today in the journal Nature, and senior author of the other, which was published in Nature Communications in February.

    The Nature Communications paper revealed that high pressure deep inside the young Earth may have driven vast stores of carbon into the planet’s core while also setting the stage for diamonds to form. In the Nature report, researchers found that water ice undergoes a complex crystalline metamorphosis as the pressure slowly ratchets up.

    Scientists have long understood that the amount of carbon sequestered in present-day Earth’s rocks, oceans and atmosphere is always in flux because the planet shuffles the element around in a vast cycle that helps regulate climate. But researchers don’t know whether the Earth locked away even more carbon deep in its interior during its formative years — information that could reveal a little more about how our planet and others like it are built.

    To pursue an answer to that question, Manning and colleagues calculated how carbon might have interacted with other atoms under conditions similar to those that prevailed roughly 4.5 billion years ago, when much of Earth was still molten. Using supercomputers, the team created simulations to explore what would happen to carbon at temperatures above 3,000 degrees Celsius (more than 5,400 degrees Fahrenheit) and at pressures more than 100,000 times of those on Earth’s surface today.

    The experiment revealed that under those conditions, carbon tends to link up with iron, which implies that there might be considerable quantities of carbon sealed in Earth’s iron core today. Researchers had already suspected that in the young planet’s magma ocean, iron atoms hooked up with one another and then dropped to the planet’s center. But the new research suggests that this molten iron rain may have also dragged carbon down with it. Until now, researchers weren’t even sure whether carbon exists down there.

    The team also found that as the pressure ramps up, carbon increasingly bonds with itself, forming long chains of carbon atoms with oxygen atoms sticking out.

    “These complex chains are a form of carbon bonding that we really hadn’t anticipated at these conditions,” Manning said.

    Such molecules could be a precursor to diamonds, which consist of many carbon atoms linked together.

    Solving an icy enigma

    The machinations of carbon under pressure provide clues as to how Earth-like planets are built. Frozen planets and moons in other solar systems, however, may also have to contend with water ice. In a separate paper, Manning and another team of scientists looked at how the molecular structure of extremely cold ice changes when put under intense pressure.

    Under everyday conditions, water ice is made up of molecules laid out in honeycomb-like mosaics of hexagons. But when ice is exposed to crushing pressure or very low temperature — in labs or possibly deep inside remote worlds — the molecules can assume a bewildering variety of patterns.

    One of those patterns, known as amorphous ice, is an enigma. In amorphous ice, the water molecules eschew rigid crystalline order and take on a free-form arrangement. Manning and colleagues set out to try and understand how amorphous ice forms.

    First, they chilled normal ice to about 170 degrees below zero Celsius (about 274 degrees below zero Fahrenheit). Then, they locked the ice in the jaws of a high-tech vice grip inside a cryogenic vacuum chamber. Finally, over the span of several hours, they slowly stepped up the pressure in the chamber to about 15,000 times atmospheric pressure. They stopped raising the pressure periodically to fire neutrons through the ice so that they could see the arrangement of the water molecules.

    Surprisingly to the researchers, the amorphous ice never formed. Instead, the molecules went through a series of previously known crystalline arrangements.

    However, when the researchers conducted the same experiment but raised the pressure much more rapidly — this time in just 30 minutes — amorphous ice formed as expected. The results suggest that time is the secret ingredient: When pressure increases slowly, tiny seeds of crystalline ice have time to form and take over the sample. Otherwise, those seeds never get a chance to grow.

    The findings, published May 23 in the journal Nature [above], could be useful to researchers who study worlds orbiting other suns and are curious about what conditions might be like deep inside frozen planets.

    “It’s entirely likely that there are planets dominated by ice in other solar systems that could obtain these pressures and temperatures with ease,” Manning said. “We have to have this right if we’re going to have a baseline for understanding the interiors of cold worlds that may not be like Earth.”

    Both papers were funded in part by the Deep Carbon Observatory, a 10-year program started in 2009 to investigate the quantities, movements, forms and origins of deep carbon inside Earth. The Nature Communications paper was also funded by the European Research Council and was co-authored by researchers at the Ecole Normale Supérieure de Lyon in France, one of whom — Natalia Solomatova — completed her undergraduate studies at UCLA. The Nature paper was co-authored by UCLA geologist Adam Makhluf and researchers from Oak Ridge National Laboratory and the National Research Council of Canada.

    See the full article here .
    See also in phys.org here.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 2:36 pm on March 8, 2019 Permalink | Reply
    Tags: "New UCLA fellowship aims to make environmental science more inclusive", “Diversity provides comfort in a work environment and shows that you can do anything despite your race religious beliefs or sexuality” said Thompson., “If you don’t have women in science you’re missing some of that talent pool” McKinnon said., “The experience of having only a small number of female peers was challenging because you always felt just a little bit out of place” said Karen McKinnon of UCLA, Center for Diverse Leadership in Science’s inaugural fellows seek to build network of support., Change is coming in the demographics of science and like most things the earliest examples come from California, Climate change touches every life on the planet — so why are so many environmental scientists white men?, In the United States 86 percent of the environmental science workforce is white and 70 percent is male., Its goal: to inspire a generation of leaders that actually matches the demographics of the U.S. population., Lack of diversity in such programs can have global implications when it comes to environmental issues., Last year UCLA became the first university to launch a center for diversity in environmental science to counter the problem., Next year Thompson will be paired with a faculty fellow for one-on-one mentorship a cornerstone of the fellowship program., Ronald Thompson a second-year environmental science student from Sacramento said he is one of few black students in most of his classes, The fellows aim to break barriers that prevent women and minorities from pursuing academic careers in the sciences through group collaboration., The inaugural fellows class consists of 47 high school undergraduate students graduate students and postdoctoral researchers along with 22 faculty fellows from UCLA., UCLA   

    From UCLA Newsroom: “New UCLA fellowship aims to make environmental science more inclusive” 


    From UCLA Newsroom

    March 07, 2019
    Sonia Aronson

    Center for Diverse Leadership in Science’s inaugural fellows seek to build network of support.

    1
    Justin Caram, assistant professor of chemistry and biochemistry in the UCLA College, and graduate student Dayanni Bhagwandin.

    Climate change touches every life on the planet — so why are so many environmental scientists white men?

    Last year, UCLA became the first university to launch a center for diversity in environmental science to counter the problem. Its goal: to inspire a generation of leaders that actually matches the demographics of the U.S. population.

    This year, the Center for Diverse Leadership in Science’s first class of fellows takes flight, building a critical mass to ensure students and faculty of diverse backgrounds have what they’ll need to succeed, from funding to a supportive community of scientists with similar backgrounds.

    “With challenges like climate change, the stakes have never been higher for ensuring we have scientific literacy coupled with representation and innovation,” said Aradhna Tripati, the center’s founder and a UCLA climate scientist. “We need every person’s imagination to overcome some of the greatest challenges our society has faced.”

    Karen McKinnon, a professor in the UCLA Institute of the Environment and Sustainability knows only too well how that sense of isolation affects a student. As one of just a few women in her doctoral program, McKinnon experienced first-hand what it’s like to be a minority in an academic setting.

    “The experience of having only a small number of female peers was challenging because you always felt just a little bit out of place,” said McKinnon, who is also a professor of statistics. “It was a visual reminder that I was not the ‘typical’ scientist.”

    In the United States, 86 percent of the environmental science workforce is white and 70 percent is male, despite the fact that the EPA found in a 2018 study that non-white communities had a 28 percent higher health burden from environmental issues. Those under the poverty line had a 35 percent higher health burden.

    The inaugural fellows class consists of 47 high school, undergraduate students, graduate students and postdoctoral researchers, along with 22 faculty fellows from UCLA. The students will work in groups on research and outreach campaigns while the faculty fellows serve as mentors and role models.

    2
    Postdoctoral scientist Adeyemi Adebiyi and Jasper Kok, associate professor of atmospheric and oceanic sciences.

    The fellows aim to break barriers that prevent women and minorities from pursuing academic careers in the sciences through group collaboration, workshop training sessions and community outreach. Students are paid for their work with financial support from the National Science Foundation and private donations.

    Ronald Thompson, a second-year environmental science student from Sacramento, said he is one of few black students in most of his classes.

    “Diversity provides comfort in a work environment and shows that you can do anything despite your race, religious beliefs or sexuality,” said Thompson, who wants to pursue a research career in conservation biology. “It lets you be comfortable with what you’re doing and makes you feel like you’re not being judged or looked at differently.”

    For his research component of the fellowship, Thompson works with other undergraduates in a group overseen by a doctoral candidate to analyze sediment from ancient lakes across the western United States. Their research aims to discover how those lakes persisted through past changes in climate — and how they might react to modern climate change. While the work is fulfilling, Thompson said the best part is working with others just as passionate as himself about the environment.

    “People go above and beyond what is required of them out of pure passion for the work they do,” Thompson said. “Everyone wants to be a part of the change that promotes a better future.”

    Next year, Thompson will be paired with a faculty fellow for one-on-one mentorship, a cornerstone of the fellowship program.

    Having a continuum of scientists at all levels — from high school students to professors — is an effective strategy to build professional communities for disenfranchised groups, Tripati said.

    “Homogenous environments cause feelings of isolation which can be detrimental to success,” Tripati said.

    Lack of diversity in such programs can have global implications when it comes to environmental issues, she added.

    “If you don’t have women in science, you’re missing some of that talent pool,” McKinnon said. “There remain a lot of fundamental questions to answer about how the climate system responds to human influence.”

    One way to make students more comfortable in class is to encourage teachers to embrace inclusive teaching techniques, said Jasper Kok, who is one of the faculty fellows and an associate professor of atmospheric and oceanic sciences in the UCLA College. Every class includes a 10-minute exercise during which students work with their neighbors.

    “Techniques that engage students and let them work collaboratively help those students who feel like they don’t belong feel more at home and more likely to stay in that field,” he said.

    For student fellow Thompson, the benefits are more personal.

    “It’s an opportunity to give back to communities and be a role model to other college students, high school students and middle school students,” he said.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 11:59 am on February 21, 2019 Permalink | Reply
    Tags: "Rare L.A. mega-storm could overwhelm dam and flood dozens of cities experts say", A government study however used computer models to estimate the effects of 900-year 7500-year and 18000-year storm events, Epic runoff from the San Gabriel Mountains could rapidly overwhelm a flood control dam on the San Gabriel river and unleash floodwaters from Pico Rivera to Long Beach says a recent analysis by the U.S, In a series of recent public hearings corps officials told residents that the 60-year-old Whittier Narrows Dam no longer met the agency’s tolerable-risk guidelines and could fail in the event of a v, In each case catastrophic flooding could extend from Pico Rivera to Long Beach inundating cities including Artesia Bell Gardens Bellflower Carson Cerritos Commerce Compton Cypress Downey Hawaiian Gard, , Scientists call it California’s “other big one”- what experts call an ARkStorm, This rare mega-storm — which some say is rendered all the more inevitable due to climate change — would last for weeks and send more than 1.5 million people fleeing as floodwaters inundated cities, UCLA, Whittier Narrows Dam   

    From L.A. Times via UCLA: “Rare L.A. mega-storm could overwhelm dam and flood dozens of cities, experts say” 

    From L.A. Times

    via

    UCLA bloc

    UCLA

    Feb 18, 2019
    Louis Sahagun

    1
    Lead engineer Douglas Chitwood at the Whittier Narrows Dam. The U.S. Army Corps of Engineers says the aging structure could fail in heavy rains. (Irfan Khan / Los Angeles Times)

    Scientists call it California’s “other big one,” and they say it could cause three times as much damage as a major earthquake ripping along the San Andreas Fault.

    Although it might sound absurd to those who still recall five years of withering drought and mandatory water restrictions, researchers and engineers warn that California may be due for rain of biblical proportions — or what experts call an ARkStorm.

    2
    (Los Angeles Times)

    This rare mega-storm — which some say is rendered all the more inevitable due to climate change — would last for weeks and send more than 1.5 million people fleeing as floodwaters inundated cities and formed lakes in the Central Valley and Mojave Desert, according to the U.S. Geological Survey. Officials estimate the structural and economic damage from an ARkStorm (for Atmospheric River 1,000) would amount to more than $725 billion statewide.

    In heavily populated areas of the Los Angeles Basin, epic runoff from the San Gabriel Mountains could rapidly overwhelm a flood control dam on the San Gabriel river and unleash floodwaters from Pico Rivera to Long Beach, says a recent analysis by the U.S. Army Corps of Engineers.

    3
    An aerial view of the Whittier Narrows Dam in the area between Montebello and Pico Rivera. (Brian van der Brug / Los Angeles Times)

    In a series of recent public hearings, corps officials told residents that the 60-year-old Whittier Narrows Dam no longer met the agency’s tolerable-risk guidelines and could fail in the event of a very large, very rare storm, such as the one that devastated California more than 150 years ago.

    Specifically, federal engineers found that the Whittier Narrows structure could fail if water were to flow over its crest or if seepage eroded the sandy soil underneath. In addition, unusually heavy rains could trigger a premature opening of the dam’s massive spillway on the San Gabriel River, releasing more than 20 times what the downstream channel could safely contain within its levees.

    The corps is seeking up to $600 million in federal funding to upgrade the 3-mile-long dam, and say the project has been classified as the agency’s highest priority nationally, due to the risk of “very significant loss of life and economic impacts.”

    The funding will require congressional approval, according to Doug Chitwood, lead engineer on the project.

    Standing atop the 56-foot-tall dam recently, Chitwood surveyed the sprawl of working-class homes, schools and commercial centers about 13 miles south of Los Angeles and said, “All you see could be underwater.”

    4
    Engineer Douglas Chitwood explains the workings of the Whittier Narrows Dam, which engineers predict would not stand up to a mega-storm. (Irfan Khan / Los Angeles Times)

    The dam — which stretches from Montebello to Pico Rivera and crosses both the San Gabriel and Rio Hondo rivers — is one of a number of flood control facilities overseen by the corps. Throughout much of the year, it contains little water.

    A government study, however, used computer models to estimate the effects of 900-year, 7,500-year and 18,000-year storm events.

    5
    (Los Angeles Times)

    In each case, catastrophic flooding could extend from Pico Rivera to Long Beach, inundating cities including Artesia, Bell Gardens, Bellflower, Carson, Cerritos, Commerce, Compton, Cypress, Downey, Hawaiian Gardens, La Palma, Lakewood, Long Beach, Lynwood, Montebello, Norwalk, Paramount, Rossmoor, Santa Fe Springs, Seal Beach and Whittier. Officials say as many as 1 million people could be affected.

    Among the communities hardest hit in a dam failure would be Pico Rivera, a city of about 63,000 people immediately below the dam. In a worst-case scenario, it could be hit with water 20 feet deep, and evacuation routes would be turned into rivers. Downey could see 15 feet of water; Santa Fe Springs, 10 feet.

    In recent years, officials with the U.S. Department of Interior and the U.S. Geological Survey have sought to raise awareness of the threat of mega-storms and promote emergency preparedness. Part of the challenge, however, has been characterizing the scale of such storms. When scientists speak of a 900-year storm, that does not mean the storm will occur every 900 years, or that such a storm cannot happen two years in a row. It means that such a storm has a 1 in 900 — or .1% — chance of occurring in any given year.

    The estimates used by the U.S. Army Corps of Engineers are intended to protect the region from a storm similar to the one that hit California during the rainy season of 1861-1862. That’s when a series of intense storms hammered the state for 45 days and dropped 36 inches of rain on Los Angeles. So much water fell that it was impossible to cross the Central Valley without a boat, and the state capital was moved temporarily from Sacramento to San Francisco.

    Some researchers, however, say climate change has cast doubt on 20th-century assumptions. They argue [nature climate change] that, in a warming world, regions such as California will experience more whiplashing shifts between extremely dry and extremely wet periods — similar to how California’s long drought was quickly followed by the wettest rainy season on record in 2016-2017. These intense cycles will seriously challenge California’s ability to control flooding as well as store and transport water.

    Daniel Swain, a UCLA climate scientist, said hydrological and forecast data used by the corps must be updated.

    “The Army Corps’ estimates of the impacts of an extremely serious weather event … are categorically underestimated,” he said. “That’s because we only have about a century of records to refer to in California. So, they are extrapolating in the dark.”

    As an example, Swain said until recently it was thought a flood the magnitude of the 1861-1862 event was likely to occur every 1,000 to 10,000 years. New research has changed that view considerably, Swain said.

    “A newer study suggests the chances of seeing another flood of that magnitude over the next 40 years are about 50-50,” he said.

    Whittier Narrows, Swain added, is therefore just one of “many pieces of water infrastructure that may not be up to the challenge of the brave new climate of the 21st century.”

    4
    Men ride horseback in the shadow of Whittier Narrows Dam, which Army Corp of Engineers officials say no longer meets their tolerable-risk guidelines. (Irfan Khan / Los Angeles Times)

    Such was the conclusion of a study conducted by UC Irvine researchers and published recently in the scientific journal Geophysical Research Letters. After examining 13 California reservoirs — most of them over 50 years old — the authors argued that the risk of dam failure was likely to increase in a warming climate. The study cited the 2017 crisis at Oroville Dam, when extreme water flows caused the dam spillway to disintegrate and triggered the evacuation of more than 180,000 people.

    In the case of Whittier Narrows Dam, Travis Longcore, a spatial scientist at USC, suggested people had grown complacent about the effectiveness of the area’s flood control system. “People tend to forget about the power of Southern California’s river systems,” he said.

    The San Gabriel River ranks among the steepest rivers in the United States, plunging 9,900 feet from boulder-strewn forks in the mountains down to Irwindale. It then meanders in a gravelly channel before arriving at lush Whittier Narrows — a natural gap in the hills that form the southern boundary of the San Gabriel Valley. From there, its flows are tamed in a concrete-covered channel for most of its final journey to the Pacific Ocean.

    Now, based on the corps’ findings, L.A. County and municipal officials are working with the federal government to develop emergency plans that can be implemented if necessary before the repair project at the dam is completed in 2026.

    Pico Rivera has undertaken an improved preparedness program, but only recently.

    Robert Alaniz, a spokesman for Pico Rivera, said the city was using a $300,000 grant from the California Department of Water Resources to revise its existing evacuation plans, which use major thoroughfares crossing the San Gabriel River to the east and Rio Hondo to the west.

    Separately, Los Angeles County Supervisor Hilda Solis said she discussed the importance of the Whittier Narrows Dam project with members of Congress during a visit to Washington, D.C., in January.

    In the meantime, David Reid, a water historian and expert on the Whittier Narrows area, suggested “the false sense of security included in the phrase ‘900-year flood’ combined with the promises of 20th century water infrastructure have put us in a bind.”

    “That’s because a mega-flood is impossible to predict,” he said. “And if the water infrastructure fails, we’re in big trouble.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 11:09 am on January 23, 2019 Permalink | Reply
    Tags: , , , , H0liCOW collaboration, , Quasar SDSS J1206+4332, Seeing double could help resolve dispute about how fast the universe is expanding, UCLA   

    From UCLA Newsroom: “Seeing double could help resolve dispute about how fast the universe is expanding” 


    From UCLA Newsroom

    January 22, 2019
    Christopher Crockett

    1
    A Hubble Space Telescope picture of a doubly imaged quasar. NASA Hubble Space Telescope, Tommaso Treu/UCLA, and Birrer et al.

    The question of how quickly the universe is expanding has been bugging astronomers for almost a century. Different studies keep coming up with different answers — which has some researchers wondering if they’ve overlooked a key mechanism in the machinery that drives the cosmos.

    Now, by pioneering a new way to measure how quickly the cosmos is expanding, a team led by UCLA astronomers has taken a step toward resolving the debate. The group’s research is published today in Monthly Notices of the Royal Astronomical Society.

    At the heart of the dispute is the Hubble constant, a number that relates distances to the redshifts of galaxies — the amount that light is stretched as it travels to Earth through the expanding universe. Estimates for the Hubble constant range from about 67 to 73 kilometers per second per megaparsec, meaning that two points in space 1 megaparsec apart (the equivalent of 3.26 million light-years) are racing away from each other at a speed between 67 and 73 kilometers per second.

    “The Hubble constant anchors the physical scale of the universe,” said Simon Birrer, a UCLA postdoctoral scholar and lead author of the study. Without a precise value for the Hubble constant, astronomers can’t accurately determine the sizes of remote galaxies, the age of the universe or the expansion history of the cosmos.

    Most methods for deriving the Hubble constant have two ingredients: a distance to some source of light and that light source’s redshift. Looking for a light source that had not been used in other scientists’ calculations, Birrer and colleagues turned to quasars, fountains of radiation that are powered by gargantuan black holes. And for their research, the scientists chose one specific subset of quasars — those whose light has been bent by the gravity of an intervening galaxy, which produces two side-by-side images of the quasar on the sky.

    Light from the two images takes different routes to Earth. When the quasar’s brightness fluctuates, the two images flicker one after another, rather than at the same time. The delay in time between those two flickers, along with information about the meddling galaxy’s gravitational field, can be used to trace the light’s journey and deduce the distances from Earth to both the quasar and the foreground galaxy. Knowing the redshifts of the quasar and galaxy enabled the scientists to estimate how quickly the universe is expanding.

    The UCLA team, as part of the international H0liCOW collaboration, had previously applied the technique to study quadruply imaged quasars, in which four images of a quasar appear around a foreground galaxy. But quadruple images are not nearly as common — double-image quasars are thought to be about five times as abundant as the quadruple ones.

    To demonstrate the technique, the UCLA-led team studied a doubly imaged quasar known as SDSS J1206+4332; they relied on data from the Hubble Space Telescope, the Gemini and W.M. Keck observatories, and from the Cosmological Monitoring of Gravitational Lenses, or COSMOGRAIL, network — a program managed by Switzerland’s Ecole Polytechnique Federale de Lausanne that is aimed at determining the Hubble constant.

    NASA/ESA Hubble Telescope

    Gemini/North telescope at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level,

    2

    Tommaso Treu, a UCLA professor of physics and astronomy and the paper’s senior author, said the researchers took images of the quasar every day for several years to precisely measure the time delay between the images. Then, to get the best estimate possible of the Hubble constant, they combined the data gathered on that quasar with data that had previously been gathered by their H0liCOW collaboration on three quadruply imaged quasars.

    “The beauty of this measurement is that it’s highly complementary to and independent of others,” Treu said.

    The UCLA-led team came up with an estimate for the Hubble constant of about 72.5 kilometers per second per megaparsec, a figure in line with what other scientists had determined in research that used distances to supernovas — exploding stars in remote galaxies — as the key measurement. However, both estimates are about 8 percent higher than one that relies on a faint glow from all over the sky called the cosmic microwave background, a relic from 380,000 years after the Big Bang, when light traveled freely through space for the first time.

    “If there is an actual difference between those values, it means the universe is a little more complicated,” Treu said.

    On the other hand, Treu said, it could also be that one measurement — or all three — are wrong.

    The researchers are now looking for more quasars to improve the precision of their Hubble constant measurement. Treu said one of the most important lessons of the new paper is that doubly imaged quasars give scientists many more useful light sources for their Hubble constant calculations. For now, though, the UCLA-led team is focusing its research on 40 quadruply imaged quasars, because of their potential to provide even more useful information than doubly imaged ones.

    Sixteen other researchers from 13 institutions in seven countries contributed to the paper; the research was supported in part by grants from NASA, the National Science Foundation and the Packard Foundation.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 5:53 pm on November 12, 2018 Permalink | Reply
    Tags: , , , MicroED-micro-electron diffraction, , NMR-nuclear magnetic resonance, , UCLA, ,   

    From Caltech: “From Beaker to Solved 3-D Structure in Minutes” 

    Caltech Logo

    From Caltech

    11/12/2018

    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Graduate student Tyler Fulton prepares samples of small molecules in a lab at Caltech. Credit: Caltech

    2
    Close-up of a powder containing small molecules like those that gave rise to 3-D structures in the new study. (The copper piece is a sample holder used with microscopes.) Credit: Caltech/Stoltz Lab

    3
    Brian Stoltz and Tyler Fulton. Credit: Caltech

    UCLA/Caltech team uncovers a new and simple way to learn the structures of small molecules.

    In a new study that one scientist called jaw-dropping, a joint UCLA/Caltech team has shown that it is possible to obtain the structures of small molecules, such as certain hormones and medications, in as little as 30 minutes. That’s hours and even days less than was possible before.

    The team used a technique called micro-electron diffraction (MicroED), which had been used in the past to learn the 3-D structures of larger molecules, specifically proteins. In this new study, the researchers show that the technique can be applied to small molecules, and that the process requires much less preparation time than expected. Unlike related techniques—some of which involve growing crystals the size of salt grains—this method, as the new study demonstrates, can work with run-of-the-mill starting samples, sometimes even powders scraped from the side of a beaker.

    “We took the lowest-brow samples you can get and obtained the highest-quality structures in barely any time,” says Caltech professor of chemistry Brian Stoltz, who is a co-author on the new study, published in the journal ACS Central Science. “When I first saw the results, my jaw hit the floor.” Initially released on the pre-print server Chemrxiv in mid-October, the article has been viewed more than 35,000 times.

    The reason the method works so well on small-molecule samples is that while the samples may appear to be simple powders, they actually contain tiny crystals, each roughly a billion times smaller than a speck of dust. Researchers knew about these hidden microcrystals before, but did not realize they could readily reveal the crystals’ molecular structures using MicroED. “I don’t think people realized how common these microcrystals are in the powdery samples,” says Stoltz. “This is like science fiction. I didn’t think this would happen in my lifetime—that you could see structures from powders.”

    4
    This movie [animated in the full article] is an example of electron diffraction (MicroED) data collection, in which electrons are fired at a nanocrystal while being continuously rotated. Data from the movie are ultimately converted to a 3-D chemical structure. Credit: UCLA/Caltech

    The results have implications for chemists wishing to determine the structures of small molecules, which are defined as those weighing less than about 900 daltons. (A dalton is about the weight of a hydrogen atom.) These tiny compounds include certain chemicals found in nature, some biological substances like hormones, and a number of therapeutic drugs. Possible applications of the MicroED structure-finding methodology include drug discovery, crime lab analysis, medical testing, and more. For instance, Stoltz says, the method might be of use in testing for the latest performance-enhancing drugs in athletes, where only trace amounts of a chemical may be present.

    “The slowest step in making new molecules is determining the structure of the product. That may no longer be the case, as this technique promises to revolutionize organic chemistry,” says Robert Grubbs, Caltech’s Victor and Elizabeth Atkins Professor of Chemistry and a winner of the 2005 Nobel Prize in Chemistry, who was not involved in the research. “The last big break in structure determination before this was nuclear magnetic resonance spectroscopy, which was introduced by Jack Roberts at Caltech in the late ’60s.”

    Like other synthetic chemists, Stoltz and his team spend their time trying to figure out how to assemble chemicals in the lab from basic starting materials. Their lab focuses on such natural small molecules as the fungus-derived beta-lactam family of compounds, which are related to penicillins. To build these chemicals, they need to determine the structures of the molecules in their reactions—both the intermediate molecules and the final products—to see if they are on the right track.

    One technique for doing so is X-ray crystallography, in which a chemical sample is hit with X-rays that diffract off its atoms; the pattern of those diffracting X-rays reveals the 3-D structure of the targeted chemical. Often, this method is used to solve the structures of really big molecules, such as complex membrane proteins, but it can also be applied to small molecules. The challenge is that to perform this method a chemist must create good-sized chunks of crystal from a sample, which isn’t always easy. “I spent months once trying to get the right crystals for one of my samples,” says Stoltz.

    Another reliable method is NMR (nuclear magnetic resonance), which doesn’t require crystals but does require a relatively large amount of a sample, which can be hard to amass. Also, NMR provides only indirect structural information.

    Before now, MicroED—which is similar to X-ray crystallography but uses electrons instead of X-rays—was mainly used on crystallized proteins and not on small molecules. Co-author Tamir Gonen, an electron crystallography expert at UCLA who began developing the MicroED technique for proteins while at the Howard Hughes Medical Institute in Virginia, said that he only started thinking about using the method on small molecules after moving to UCLA and teaming up with Caltech.

    “Tamir had been using this technique on proteins, and just happened to mention that they can sometimes get it to work using only powdery samples of proteins,” says Hosea Nelson (PhD ’13), an assistant professor of chemistry and biochemistry at UCLA. “My mind was blown by this, that you didn’t have to grow crystals, and that’s around the time that the team started to realize that we could apply this method to a whole new class of molecules with wide-reaching implications for all types of chemistry.”

    The team tested several samples of varying qualities, without ever attempting to crystallize them, and were able to determine their structures thanks to the samples’ ample microcrystals. They succeeded in getting structures for ground-up samples of the brand-name drugs Tylenol and Advil, and they were able to identify distinct structures from a powdered mixture of four chemicals.

    The UCLA/Caltech team says it hopes this method will become routine in chemistry labs in the future.

    “In our labs, we have students and postdocs making totally new and unique molecular entities every day,” says Stoltz. “Now we have the power to rapidly figure out what they are. This is going to change synthetic chemistry.”

    The study was funded by the National Science Foundation, the National Institutes of Health, the Department of Energy, a Beckman Young Investigators award, a Searle Scholars award, a Pew Scholars award, the Packard Foundation, the Sloan Foundation, the Pew Charitable Trusts, and the Howard Hughes Medical Institute. Other co-authors include Christopher Jones,Michael Martynowycz, Johan Hattne, and Jose Rodriguez of UCLA; and Tyler Fulton of Caltech.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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