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  • richardmitnick 9:14 am on June 4, 2019 Permalink | Reply
    Tags: "For The First Time Physicists Have Produced a Stunning Type of Plasma Jet in The Lab", , , Rice University   

    From Rice University via From Science Alert: “For The First Time, Physicists Have Produced a Stunning Type of Plasma Jet in The Lab” 

    Rice U bloc

    From Rice University

    via

    ScienceAlert

    From Science Alert

    4 JUN 2019
    DAVID NIELD

    1
    OMEGA laser. (Rather Anonymous/Flickr/CC BY NC 2.0)

    Plasma, that super-hot mix of electrified atomic particles, plays a key role in the evolution of stars, black holes, and other cosmic elements. For closer study though, plasma needs to be recreated in a lab – and researchers have just managed to generate a particular type of plasma jet for the first time.

    The key characteristics of this lab-created plasma jet are its stability and its magnetism. Further study of the jet could help us unlock some more of the secrets of the Universe.

    Not only that, the scientists were able to run some advanced diagnostics on the jet – getting readings for its density, temperature, length, coherence, and magnetic field – which helps them better compare it to plasma out in space.

    “We are now creating stable, supersonic, and strongly magnetised plasma jets in a laboratory that might allow us to study astrophysical objects light years away,” says one of the team leaders, astrophysicist Edison Liang from Rice University in Texas.

    The researchers trained 20 individual laser beams into a circular shape on a plastic target to produce puffs of plasma, which were then pressurised as they expanded to create a plasma jet four millimetres (0.16 inches) in length, with a magnetic field strength of over 100 tesla (about 10,000 times stronger than a small bar magnet).

    Those original laser beams weren’t any ordinary lights, though – they were produced by the OMEGA laser at the Laboratory for Laser Energetics, part of the University of Rochester in New York. It’s one of the most powerful lasers in the world, capable of focussing huge energy bursts on very small targets.

    U Rochester OMEGA EP Laser System


    U Rochester Omega Laser

    Thanks to the diagnostic work the researchers carried out on the plasma jet, they now have a baseline to use to see how the plasma reacts under different conditions.

    Future tests will involve different types of plasma-related phenomena, such as using an external magnetic field to see if the jet grows in size and becomes more collimated (with parallel rays).

    The researchers also want to try the same experiment with the National Ignition Facility at Lawrence Livermore National Laboratory, which has no fewer than 192 laser beams – half of those could contribute to the plasma laser ring.

    “It would have a larger radius and thus produce a longer jet than that produced using OMEGA,” says one of the lead researchers, physicist Lan Gao from the Princeton Plasma Physics Laboratory (PPPL). “This process would help us figure out under which conditions the plasma jet is strongest.”

    The circle method the researchers developed here has the potential to scale up very well, the researchers say, and is similar to the plasma offshoots that might be observed from a newborn star – only easier to study up close.

    As the research continues, we should learn more about this special state of matter and the role it plays in the wider cosmos (as well as any ordinary microwave, if the right conditions are met).

    “This is groundbreaking research because no other team has successfully launched a supersonic, narrowly beamed jet that carries such a strong magnetic field, extending to significant distances,” says Liang.

    “This is the first time that scientists have demonstrated that the magnetic field does not just wrap around the jet, but also extends parallel to the jet’s axis.”

    The research has been published in The Astrophysical Journal Letters.

    See the full article here .


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


    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 11:55 am on May 6, 2019 Permalink | Reply
    Tags: "Organ bioprinting gets a breath of fresh air", 3D printing replacement organs, , , , Rice University,   

    From Rice University and UW Medicine: “Organ bioprinting gets a breath of fresh air” 

    U Washington
    University of Washington

    UW Medicine Newsroom

    Rice U bloc

    From Rice University

    May 2, 2019
    David Ruth
    713-348-6327
    david@rice.edu

    Jade Boyd
    713-348-6778
    jadeboyd@rice.edu

    Bioengineers clear major hurdle on path to 3D printing replacement organs.

    Bioengineers have cleared a major hurdle on the path to 3D printing replacement organs with a breakthrough technique for bioprinting tissues.

    1
    The May 3 issue of Science features a breakthrough bioprinting technique developed by Rice University bioengineer Jordan Miller and colleagues. (Reprinted with permission from AAAS. Photo by Dan Sazer, Jeff Fitlow and Jordan Miller/Rice University)

    The new innovation allows scientists to create exquisitely entangled vascular networks that mimic the body’s natural passageways for blood, air, lymph and other vital fluids.

    The research is featured on the cover of this week’s issue of Science. It includes a visually stunning proof-of-principle — a hydrogel model of a lung-mimicking air sac in which airways deliver oxygen to surrounding blood vessels. Also reported are experiments to implant bioprinted constructs containing liver cells into mice.

    The work was led by bioengineers Jordan Miller of Rice University and Kelly Stevens of the University of Washington (UW) and included 15 collaborators from Rice, UW, Duke University, Rowan University and Nervous System, a design firm in Somerville, Massachusetts.

    “One of the biggest road blocks to generating functional tissue replacements has been our inability to print the complex vasculature that can supply nutrients to densely populated tissues,” said Miller, assistant professor of bioengineering at Rice’s Brown School of Engineering. “Further, our organs actually contain independent vascular networks — like the airways and blood vessels of the lung or the bile ducts and blood vessels in the liver. These interpenetrating networks are physically and biochemically entangled, and the architecture itself is intimately related to tissue function. Ours is the first bioprinting technology that addresses the challenge of multivascularization in a direct and comprehensive way.”

    Stevens, assistant professor of bioengineering in the UW College of Engineering, assistant professor of pathology in the UW School of Medicine, and an investigator at the UW Medicine Institute for Stem Cell and Regenerative Medicine, said multivascularization is important because form and function often go hand in hand.

    3
    Rice University bioengineering graduate student Bagrat Grigoryan led the development of a new technique for 3D printing tissue with entangled vascular networks similar to the body’s natural passageways for blood, air and other vital fluids. (Photo by Jeff Fitlow/Rice University)

    “Tissue engineering has struggled with this for a generation,” Stevens said. “With this work we can now better ask, ‘If we can print tissues that look and now even breathe more like the healthy tissues in our bodies, will they also then functionally behave more like those tissues?’ This is an important question, because how well a bioprinted tissue functions will affect how successful it will be as a therapy.”

    The goal of bioprinting healthy, functional organs is driven by the need for organ transplants. More than 100,000 people are on transplant waiting lists in the United States alone, and those who do eventually receive donor organs still face a lifetime of immune-suppressing drugs to prevent organ rejection. Bioprinting has attracted intense interest over the past decade because it could theoretically address both problems by allowing doctors to print replacement organs from a patient’s own cells. A ready supply of functional organs could one day be deployed to treat millions of patients worldwide.

    “We envision bioprinting becoming a major component of medicine within the next two decades,” Miller said.

    4
    Rice University bioengineers (from left) Bagrat Grigoryan, Jordan Miller and Daniel Sazer and collaborators created a breakthrough bioprinting technique that could speed development of technology for 3D printing replacement organs and tissues. (Photo by Jeff Fitlow/Rice University)

    “The liver is especially interesting because it performs a mind-boggling 500 functions, likely second only to the brain,” Stevens said. “The liver’s complexity means there is currently no machine or therapy that can replace all its functions when it fails. Bioprinted human organs might someday supply that therapy.”

    To address this challenge, the team created a new open-source bioprinting technology dubbed the “stereolithography apparatus for tissue engineering,” or SLATE. The system uses additive manufacturing to make soft hydrogels one layer at a time.

    Layers are printed from a liquid pre-hydrogel solution that becomes a solid when exposed to blue light. A digital light processing projector shines light from below, displaying sequential 2D slices of the structure at high resolution, with pixel sizes ranging from 10-50 microns. With each layer solidified in turn, an overhead arm raises the growing 3D gel just enough to expose liquid to the next image from the projector. The key insight by Miller and Bagrat Grigoryan, a Rice graduate student and lead co-author of the study, was the addition of food dyes that absorb blue light. These photoabsorbers confine the solidification to a very fine layer. In this way, the system can produce soft, water-based, biocompatible gels with intricate internal architecture in a matter of minutes.

    5
    Rice University bioengineer Daniel Sazer prepares a scale-model of a lung-mimicking air sac for testing. In experiments, air is pumped into the sac in a pattern that mimics breathing while blood is flowed through a surrounding network of blood vessels to oxygenate human red blood cells. (Photo by Jeff Fitlow/Rice University)

    Tests of the lung-mimicking structure showed that the tissues were sturdy enough to avoid bursting during blood flow and pulsatile “breathing,” a rhythmic intake and outflow of air that simulated the pressures and frequencies of human breathing. Tests found that red blood cells could take up oxygen as they flowed through a network of blood vessels surrounding the “breathing” air sac. This movement of oxygen is similar to the gas exchange that occurs in the lung’s alveolar air sacs.

    To design the study’s most complicated lung-mimicking structure, which is featured on the cover of Science, Miller collaborated with study co-authors Jessica Rosenkrantz and Jesse Louis-Rosenberg, co-founders of Nervous System.

    “When we founded Nervous System it was with the goal of adapting algorithms from nature into new ways to design products,” Rosenkrantz said. “We never imagined we’d have the opportunity to bring that back and design living tissues.”

    6
    Experiments performed by Rice University and University of Washington researchers explored whether liver cells called hepatocytes would function normally if they were incorporated into a bioprinted implant and surgically implanted in mice for 14 days. (Image courtesy of Jordan Miller/Rice University)

    In the tests of therapeutic implants for liver disease, the team 3D printed tissues, loaded them with primary liver cells and implanted them into mice. The tissues had separate compartments for blood vessels and liver cells and were implanted in mice with chronic liver injury. Tests showed that the liver cells survived the implantation.

    Miller said the new bioprinting system can also produce intravascular features, like bicuspid valves that allow fluid to flow in only one direction. In humans, intravascular valves are found in the heart, leg veins and complementary networks like the lymphatic system that have no pump to drive flow.

    “With the addition of multivascular and intravascular structure, we’re introducing an extensive set of design freedoms for engineering living tissue,” Miller said. “We now have the freedom to build many of the intricate structures found in the body.”

    Miller and Grigoryan are commercializing key aspects of the research through a Houston-based startup company called Volumetric. The company, which Grigoryan has joined full time, is designing and manufacturing bioprinters and bioinks.

    7
    Assistant professor Kelly Stevens (left) and graduate student Daniel Corbett (right) from the University of Washington Departments of Bioengineering and Pathology helped develop a new method to bioprint liver tissue. (Photo by Dennis R. Wise/University of Washington)

    Miller, a longstanding champion of open-source 3D printing, said all source data from the experiments in the published Science study are freely available [see the Science paper above]. In addition, all 3D printable files needed to build the stereolithography printing apparatus are available, as are the design files for printing each of the hydrogels used in the study.

    See the full Rice university article here .
    See the full U Washington Medicine article here .


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

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

    About UW Medicine

    UW Medicine is one of the top-rated academic medical systems in the world. With a mission to improve the health of the public, UW Medicine educates the next generation of physicians and scientists, leads one of the world’s largest and most comprehensive biomedical research programs, and provides outstanding care to patients from across the globe.

    The UW School of Medicine, part of the UW Medicine system, leads the internationally recognized, community-based WWAMI Program, serving the states of Washington, Wyoming, Alaska, Montana and Idaho. The school has been ranked No. 1 in the nation in primary-care training for more than 20 years by U.S. News & World Report. It is also second in the nation in federal research grants and contracts with $749.9 million in total revenue (fiscal year 2016) according to the Association of American Medical Colleges.

    UW Medicine has more than 27,000 employees and an annual budget of nearly $5 billion. Also part of the UW Medicine system are Airlift Northwest and the UW Physicians practice group, the largest physician practice plan in the region. UW Medicine shares in the ownership and governance of the Seattle Cancer Care Alliance with Fred Hutchinson Cancer Research Center and Seattle Children’s, and also shares in ownership of Children’s University Medical Group with Seattle Children’s.

    u-washington-campus
    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 2:05 pm on February 18, 2019 Permalink | Reply
    Tags: "Can we trust scientific discoveries made using machine learning?", , , Machine learning (ML) is a branch of statistics and computer science concerned with building computational systems that learn from data rather than following explicit instructions, Rice University   

    From Rice University: “Can we trust scientific discoveries made using machine learning?” 

    Rice U bloc

    From Rice University

    February 18, 2019

    Jeff Falk
    713-348-6775
    jfalk@rice.edu

    Jade Boyd
    713-348-6778
    jadeboyd@rice.edu

    Rice U. expert: Key is creating ML systems that question their own predictions.

    Rice University statistician Genevera Allen says scientists must keep questioning the accuracy and reproducibility of scientific discoveries made by machine-learning techniques until researchers develop new computational systems that can critique themselves.

    1
    Genevera Allen (Photo by Tommy LaVergne/Rice University)

    Allen, associate professor of statistics, computer science and electrical and computer engineering at Rice and of pediatrics-neurology at Baylor College of Medicine, will address the topic in both a press briefing and a general session today at the 2019 Annual Meeting of the American Association for the Advancement of Science (AAAS).

    “The question is, ‘Can we really trust the discoveries that are currently being made using machine-learning techniques applied to large data sets?’” Allen said. “The answer in many situations is probably, ‘Not without checking,’ but work is underway on next-generation machine-learning systems that will assess the uncertainty and reproducibility of their predictions.”

    Machine learning (ML) is a branch of statistics and computer science concerned with building computational systems that learn from data rather than following explicit instructions. Allen said much attention in the ML field has focused on developing predictive models that allow ML to make predictions about future data based on its understanding of data it has studied.

    “A lot of these techniques are designed to always make a prediction,” she said. “They never come back with ‘I don’t know,’ or ‘I didn’t discover anything,’ because they aren’t made to.”

    She said uncorroborated data-driven discoveries from recently published ML studies of cancer data are a good example.

    “In precision medicine, it’s important to find groups of patients that have genomically similar profiles so you can develop drug therapies that are targeted to the specific genome for their disease,” Allen said. “People have applied machine learning to genomic data from clinical cohorts to find groups, or clusters, of patients with similar genomic profiles.

    “But there are cases where discoveries aren’t reproducible; the clusters discovered in one study are completely different than the clusters found in another,” she said. “Why? Because most machine-learning techniques today always say, ‘I found a group.’ Sometimes, it would be far more useful if they said, ‘I think some of these are really grouped together, but I’m uncertain about these others.’”

    Allen will discuss uncertainty and reproducibility of ML techniques for data-driven discoveries at a 10 a.m. press briefing today, and she will discuss case studies and research aimed at addressing uncertainty and reproducibility in the 3:30 p.m. general session, “Machine Learning and Statistics: Applications in Genomics and Computer Vision.” Both sessions are at the Marriott Wardman Park Hotel.

    Allen is the founding director of Rice’s Center for Transforming Data to Knowledge (D2K Lab) and a member of the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital. Her research lies in the areas of modern multivariate analysis, graphical models, statistical machine learning and data integration, with a particular focus on statistical methods that help scientists make sense of “big data” from high-throughput genomics, neuroimaging and other applications. Her previous honors include a National Science Foundation CAREER award, the International Biometric Society’s Young Statistician Showcase award and Forbes ’30 under 30′ in science and health care.

    AAAS is the world’s largest multi-disciplinary science society, and the AAAS Annual Meeting, Feb. 14-17, is the world’s largest general scientific gathering. For more information, visit: https://aaas.org.

    See the full article here .


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

    stem

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 12:58 pm on January 7, 2019 Permalink | Reply
    Tags: , , , , Plasma is an electrically conductive mix of electrons and ions, Rice University, Rice University physicists are first to laser cool neutral plasma, Ultracold simulators of super-dense stars   

    From Rice University: ” Ultracold simulators of super-dense stars” 

    Rice U bloc

    From Rice University

    January 3, 2019
    Jade Boyd

    Rice University physicists are first to laser cool neutral plasma.

    Rice University physicists have created the world’s first laser-cooled neutral plasma, completing a 20-year quest that sets the stage for simulators that re-create exotic states of matter found inside Jupiter and white dwarf stars.

    The findings are detailed this week in the journal Science and involve new techniques for laser cooling clouds of rapidly expanding plasma to temperatures about 50 times colder than deep space.

    “We don’t know the practical payoff yet, but every time physicists have laser cooled a new kind of thing, it has opened a whole world of possibilities,” said lead scientist Tom Killian, professor of physics and astronomy at Rice. “Nobody predicted that laser cooling atoms and ions would lead to the world’s most accurate clocks or breakthroughs in quantum computing. We do this because it’s a frontier.”

    Killian and graduate students Tom Langin and Grant Gorman used 10 lasers of varying wavelengths to create and cool the neutral plasma. They started by vaporizing strontium metal and using one set of intersecting laser beams to trap and cool a puff of strontium atoms about the size of a child’s fingertip. Next, they ionized the ultracold gas with a 10-nanosecond blast from a pulsed laser. By stripping one electron from each atom, the pulse converted the gas to a plasma of ions and electrons.

    1
    Rice University physicists reported the first laser-cooled neutral plasma, a breakthrough that could lead to simulators for exotic states of matter that occur at the center of Jupiter or white dwarf stars. (Photo by Brandon Martin/Rice University)

    Energy from the ionizing blast causes the newly formed plasma to expand rapidly and dissipate in less than one thousandth of a second. This week’s key finding is that the expanding ions can be cooled with another set of lasers after the plasma is created. Killian, Langin and Gorman describe their techniques in the new paper, clearing the way for their lab and others to make even colder plasmas that behave in strange, unexplained ways.

    Plasma is an electrically conductive mix of electrons and ions. It is one of four fundamental states of matter; but unlike solids, liquids and gases, which are familiar in daily life, plasmas tend to occur in very hot places like the surface of the sun or a lightning bolt. By studying ultracold plasmas, Killian’s team hopes to answer fundamental questions about how matter behaves under extreme conditions of high density and low temperature.

    To make its plasmas, the group starts with laser cooling, a method for trapping and slowing particles with intersecting laser beams. The less energy an atom or ion has, the colder it is, and the slower it moves about randomly. Laser cooling was developed in the 1990s to slow atoms until they are almost motionless, or just a few millionths of a degree above absolute zero.

    2
    Rice University graduate student Tom Langin makes an adjustment to an experiment that uses dozens of lasers of varying wavelengths to laser-cool ions in a neutral plasma that is made by first laser-cooling strontium atoms and then ionizing them with a high-power laser. (Photo by Brandon Martin/Rice University)

    “If an atom or ion is moving, and I have a laser beam opposing its motion, as it scatters photons from the beam it gets momentum kicks that slow it,” Killian said. “The trick is to make sure that light is always scattered from a laser that opposes the particle’s motion. If you do that, the particle slows and slows and slows.”

    During a postdoctoral fellowship at the National Institute of Standards and Technology in Bethesda, Md., in 1999, Killian pioneered the ionization method for creating neutral plasma from a laser-cooled gas. When he joined Rice’s faculty the following year, he started a quest for a way to make the plasmas even colder. One motivation was to achieve “strong coupling,” a phenomenon that happens naturally in plasmas only in exotic places like white dwarf stars and the center of Jupiter.

    “We can’t study strongly coupled plasmas in places where they naturally occur,” Killian said. “Laser cooling neutral plasmas allows us to make strongly coupled plasmas in a lab, so that we can study their properties.

    “In strongly coupled plasmas, there is more energy in the electrical interactions between particles than in the kinetic energy of their random motion,” Killian said. “We mostly focus on the ions, which feel each other, and rearrange themselves in response to their neighbors’ positions. That’s what strong coupling means.”

    3
    To laser-cool a neutral plasma, Rice University physicists start by vaporizing billions of strontium atoms, which are laser-cooled and laser-ionized to create a rapidly expanding cloud of neutral ions. Another set of lasers cools the ions. (Photo by Brandon Martin/Rice University)

    Because the ions have positive electric charges, they repel one another through the same force that makes your hair stand up straight if it gets charged with static electricity.

    “Strongly coupled ions can’t be near one another, so they try to find equilibrium, an arrangement where the repulsion from all of their neighbors is balanced,” he said. “This can lead to strange phenomena like liquid or even solid plasmas, which are far outside our normal experience.”

    In normal, weakly coupled plasmas, these repulsive forces only have a small influence on ion motion because they’re far outweighed by the effects of kinetic energy, or heat.

    “Repulsive forces are normally like a whisper at a rock concert,” Killian said. “They’re drowned out by all the kinetic noise in the system.”

    In the center of Jupiter or a white dwarf star, however, intense gravity squeezes ions together so closely that repulsive forces, which grow much stronger at shorter distances, win out. Even though the temperature is quite high, ions become strongly coupled.

    4
    Rice University graduate student Tom Langin at the laser-table where beams of various wavelengths were used to make the world’s first ultracold neutral plasma. (Photo by Brandon Martin/Rice University)

    Killian’s team creates plasmas that are orders of magnitude lower in density than those inside planets or dead stars, but by lowering the temperature they raise the ratio of electric-to-kinetic energies. At temperatures as low as one-tenth of a Kelvin above absolute zero, Killian’s team has seen repulsive forces take over.

    “Laser cooling is well developed in gases of neutral atoms, for example, but the challenges are very different in plasmas,” he said.

    “We are just at the beginning of exploring the implications of strong coupling in ultracold plasmas,” Killian said. “For example, it changes the way that heat and ions diffuse through the plasma. We can study those processes now. I hope this will improve our models of exotic, strongly coupled astrophysical plasmas, but I am sure we will also make discoveries that we haven’t dreamt of yet. This is the way science works.”

    The research was supported by the Air Force Office of Scientific Research and the Department of Energy’s Office of Science.

    See the full article here .


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

    stem

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 10:17 pm on May 29, 2018 Permalink | Reply
    Tags: , New role for asthenosphere in plate movements, , Rice University   

    From Rice University: “Flow in the asthenosphere drags tectonic plates along” 

    Rice U bloc

    From Rice University

    May 29, 2018
    Jade Boyd

    Rice University’s 3D model suggests new role for asthenosphere in plate movements.

    1
    A graphic showing the convective heat cycle (red arrows) that drive plate tectonic motion (black arrows) on Earth. Heat flows toward subduction zones through the uppermost mantle layer, the asthenosphere. A realistic new computer model from Rice University finds that the asthenosphere moves and drags plates along with it rather than acting as a brake on plate movements as had been widely believed. (Image courtesy of Surachit/Wikimedia Commons)

    New simulations of Earth’s asthenosphere find that convective cycling and pressure-driven flow can sometimes cause the planet’s most fluid layer of mantle to move even faster than the tectonic plates that ride atop it.

    That’s one conclusion from a new study by Rice University geophysicists who modeled flow in the 100-mile-thick layer of mantle that begins at the base of Earth’s tectonic plates, or lithosphere.

    The study, in the journal Earth and Planetary Science Letters, takes aim at a much-debated question in geophysics: What drives the movement of Earth’s tectonic plates, the 57 interlocking slabs of the lithosphere that slip, grind and bump against one another in a seismic dance that causes earthquakes, builds continents and gradually reshapes the planet’s surface every few million years?

    The tectonic plates of the world were mapped in 1996, USGS.

    “Tectonic plates float on top of the asthenosphere, and the leading theory for the past 40 years is that the lithosphere moves independently of the asthenosphere, and the asthenosphere only moves because the plates are dragging it along,” said graduate student Alana Semple, lead co-author of the new study. “Detailed observations of the asthenosphere from a Lamont research group returned a more nuanced picture and suggested, among other things, that the asthenosphere has a constant speed at its center but is changing speeds at its top and base, and that it sometimes appears to flow in a different direction than the lithosphere.”

    Computational modeling carried out at Rice offers a theoretical framework that can explain these puzzling observations, said Adrian Lenardic, a study co-author and professor of Earth, environmental and planetary sciences at Rice.

    “We’ve shown how these situations can occur through a combination of plate- and pressure-driven flow in the asthenosphere,” he said. “The key was realizing that a theory developed by former Rice postdoc Tobias Höink had the potential to explain the Lamont observations if a more accurate representation of the asthenosphere’s viscosity was allowed for. Alana’s numerical simulations incorporated that type of viscosity and showed that the modified model could explain the new observations. In the process, this offered a new way of thinking about the relationship between the lithosphere and asthenosphere.”

    Though the asthenosphere is made of rock, it is under intense pressure that can cause its contents to flow.

    “Thermal convection in Earth’s mantle generates dynamic pressure variations,” Semple said. “The weakness of the asthenosphere, relative to tectonic plates above, allows it to respond differently to the pressure variations. Our models show how this can lead to asthenosphere velocities that exceed those of plates above. The models also show how flow in the asthenosphere can be offset from that of plates, in line with the observations from the Lamont group”

    The oceanic lithosphere is formed at mid-ocean ridges and flows toward subduction zones where one tectonic plate slides beneath another. In the process, the lithosphere cools and heat from Earth’s interior is transferred to its surface. Subduction recycles cooler lithospheric material into the mantle, and the cooling currents flow back into the deep interior.

    Semple’s 3D model simulates both this convective cycle and the asthenosphere. She credited Rice’s Center for Research Computing (CRC) for its help running simulations — some of which took as long as six weeks — on Rice’s DAVinCI supercomputer.

    Rice DAVinCI IBM iDataPlex supercomputer

    Semple said the simulations show how convective cycling and pressure-driven flow can drive tectonic movement.

    “Our paper suggests that pressure-driven flow in the asthenosphere can contribute to the motion of tectonic plates by dragging plates along with it,” she said. “A notable contribution does come from ‘slab-pull,’ a gravity-driven process that pulls plates toward subduction zones. Slab-pull can still be the dominant process that moves plates, but our models show that asthenosphere flow provides a more significant contribution to plate movement than previously thought.”

    The research was supported by the National Science Foundation. DAVinCI is administered by CRC and was procured in partnership with Rice’s Ken Kennedy Institute for Information Technology.

    See the full article here .


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

    stem

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 10:16 am on March 2, 2018 Permalink | Reply
    Tags: , , , Rice University, Rydberg polarons   

    From Rice: “Dressing atoms in an ultracold soup” 

    Rice U bloc

    Rice University

    February 28, 2018
    Jade Boyd

    Physicists build bizarre molecules called ‘Rydberg polarons’

    Using lasers, U.S. and Austrian physicists have coaxed ultracold strontium atoms into complex structures unlike any previously seen in nature.

    “I am amazed that we’ve discovered a new way that atoms assemble,” said Rice University physicist Tom Killian. “It shows how rich the laws of physics and chemistry can be.” Killian is the lead scientist on a new paper in Physical Review Letters that summarized the group’s experimental findings.

    Killian teamed with experimental physicists from Rice’s Center for Quantum Materials and theoretical physicists from Harvard University and Vienna University of Technology on the two-year project to create “Rydberg polarons” out of strontium atoms that were at least 1 million times colder than deep space.

    The team’s findings, which are summarized in the PRL paper and a companion theoretical study appearing this week in Physical Review A, reveal something new about the basic nature of matter, Killian said.

    “The basic laws that we learn in chemistry class tell us how atoms bond together to form molecules, and a deep understanding of those principles is what allows chemists and engineers to make the materials we use in our everyday lives,” he said. “But those laws are also quite rigid. Only certain combinations of atoms will form stable bonds in a molecule. Our work explored a new type of molecule that isn’t described by any of the traditional rules for binding atoms together.”

    1
    Rice University physicists (clockwise from left) Soumya Kanungo, Tom Killian, Roger Ding, Barry Dunning and Joe Whalen used lasers and an ultracold strontium gas to make “Rydberg polarons,” complex molecules unlike any previously seen in nature. (Photo by Jeff Fitlow/Rice University)

    Killian said the new molecules are only stable at extraordinarily cold temperatures — about a millionth of a degree above absolute zero. At such low temperatures, the constituent atoms stay still long enough to become “glued together” in new, complex structures, he said.

    “One amazing thing is that you can keep attaching an arbitrary number of atoms to these molecules,” Killian said. “It’s just like attaching Lego blocks, which you can’t do with traditional types of molecules.”

    He said the discovery will be of interest to theoretical chemists, condensed matter physicists, atomic physicists and physicists who are studying Rydberg atoms for potential use in quantum computers.

    “Nature takes advantage of a fascinating toolbox of tricks for binding atoms together to make molecules and materials,” Killian said. “As we discover and understand these tricks, we satisfy our innate curiosity about the world we live in, and it can often lead to practical advances like new therapeutic drugs or light-harvesting solar cells. It is too early to tell if any practical applications will come from our work, but basic research like this is what it takes to find tomorrow’s great breakthroughs.”

    The team’s efforts centered around making, measuring and predicting the behavior of a specific state of matter called a Rydberg polaron, a combination of two distinct phenomena, Rydberg atoms and polarons.

    In Rydberg atoms, one or more electrons are excited with a precise amount of energy so that they orbit far from the atom’s nucleus. Rydberg atoms can be described with simple rules written down more than a century ago by Swedish physicist Johannes Rydberg. They have been studied in laboratories for decades and are believed to exist in cold reaches of deep space. The Rydberg atoms in the PRL study were up to one micron wide, about 1,000 times larger than normal strontium atoms.

    2
    Rice University atomic physicist Joe Whalen works on a laser cooling system for ultracold strontium gas. (Photo by Jeff Fitlow/Rice University)

    Polarons are created when a single particle interacts strongly with its environment and causes nearby electrons, ions or atoms to rearrange themselves and form a sort of coating that the particle carries with it. The polaron itself is a collective — a unified object known as a quasiparticle — that incorporates properties of the original particle and its environment.

    Rydberg polarons are a new class of polarons in which the high-energy, far-orbiting electron gathers hundreds of atoms within its orbit as it moves through a dense, ultracold cloud. In the Rice experiments, researchers began by creating a supercooled cloud of several hundred thousand strontium atoms. By coordinating the timing of laser pulses with changes in the electric field, the researchers were able to create and count Rydberg polarons one by one, ultimately forming millions of them for their study.

    While Rydberg polarons had previously been created with rubidium, the use of strontium allowed the physicists to more clearly resolve the energy of the coated Rydberg atoms in a way that revealed previously unseen universal characteristics.

    “I give a lot of credit to the theorists,” said Killian, a professor of physics and astronomy. “They developed powerful techniques to calculate the structure of hundreds of interacting particles in order to interpret our results and identify the signatures of the Rydberg polarons.

    “From an experimental standpoint, it was challenging to make and measure these polarons,” he said. “Each one lived for only a few microseconds before collisions with other particles tore it apart. We had to use very sensitive techniques to count these fragile and fleeting objects.”

    Study co-authors include Joe Whalen, Roger Ding and Barry Dunning, all of Rice; Francisco Camargo, formerly of Rice and now of AMD; Germano Woehl Jr., formerly of Rice and now of the University of the São Paulo; Shuhei Yoshida and Joachim Burgdörfer of Vienna University of Technology; Hossein Sadeghpour of the Harvard-Smithsonian Center for Astrophysics; and Richard Schmidt and Eugene Demler of Harvard University.

    The research was supported by the Air Force Office of Scientific Research, the National Science Foundation, the Robert A. Welch Foundation, the Austrian Science Fund, the Army Research Office, Dr. Max Rössler, the Walter Haefner Foundation and the ETH Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 4:41 pm on December 18, 2017 Permalink | Reply
    Tags: , , Engineers develop microfluidic devices- microelectrodes for gentle implantation, , Nanotubes go with the flow to penetrate brain tissue, Rice University, The device uses the force applied by fast-moving fluids that gently advance insulated flexible fibers into brain tissue without buckling, The electrode is like a cooked noodle that you’re trying to put into a bowl of Jell-O” said Rice engineer Jacob Robinson   

    From Rice: “Nanotubes go with the flow to penetrate brain tissue” 

    Rice U bloc

    Rice University

    December 18, 2017
    Mike Williams

    Rice scientists, engineers develop microfluidic devices, microelectrodes for gentle implantation.

    Rice University researchers have invented a device that uses fast-moving fluids to insert flexible, conductive carbon nanotube fibers into the brain, where they can help record the actions of neurons.

    The Rice team’s microfluidics-based technique promises to improve therapies that rely on electrodes to sense neuronal signals and trigger actions in patients with epilepsy and other conditions.

    Eventually, the researchers said, nanotube-based electrodes could help scientists discover the mechanisms behind cognitive processes and create direct interfaces to the brain that will allow patients to see, to hear or to control artificial limbs.

    The device uses the force applied by fast-moving fluids that gently advance insulated flexible fibers into brain tissue without buckling. This delivery method could replace hard shuttles or stiff, biodegradable sheaths used now to deliver wires into the brain. Both can damage sensitive tissue along the way.

    The technology is the subject of a paper in the American Chemical Society journal Nano Letters.

    Lab and in vivo experiments showed how the microfluidic devices force a viscous fluid to flow around a thin fiber electrode. The fast-moving fluid slowly pulls the fiber forward through a small aperture that leads to the tissue. Once it crosses into the tissue, tests showed the wire, though highly flexible, stays straight.

    1
    Fast-moving fluid pulls a fiber through a microfluidic device to be inserted into brain tissue. The device invented at Rice University could provide a gentler method to implant wires into patients with neurological diseases and help scientists explore cognitive processes and develop implants to help people to see, to hear and to control artificial limbs. Courtesy of the Robinson Lab.

    “The electrode is like a cooked noodle that you’re trying to put into a bowl of Jell-O,” said Rice engineer Jacob Robinson, one of three project leaders. “By itself, it doesn’t work. But if you put that noodle under running water, the water pulls the noodle straight.”

    The wire moves slowly relative to the speed of the fluid. “The important thing is we’re not pushing on the end of the wire or at an individual location,” said co-author Caleb Kemere, a Rice electrical and computer engineer who specializes in neuroscience. “We’re pulling along the whole cross-section of the electrode and the force is completely distributed.”

    “It’s easier to pull things that are flexible than it is to push them,” Robinson said.

    “That’s why trains are pulled, not pushed,” said chemist Matteo Pasquali, a co-author. “That’s why you want to put the cart behind the horse.”

    The fiber moves through an aperture about three times its size but still small enough to let very little of the fluid through. Robinson said none of the fluid follows the wire into brain tissue (or, in experiments, the agarose gel that served as a brain stand-in).

    There’s a small gap between the device and the tissue, Robinson said. The small length of fiber in the gap stays on course like a whisker that remains stiff before it grows into a strand of hair. “We use this very short, unsupported length to allow us to penetrate into the brain and use the fluid flow on the back end to keep the electrode stiff as we move it down into the tissue,” he said.

    “Once the wire is in the tissue, it’s in an elastic matrix, supported all around by the gel material,” said Pasquali, a carbon nanotube fiber pioneer whose lab made a custom fiber for the project. “It’s supported laterally, so the wire can’t easily buckle.”

    Carbon nanotube fibers conduct electrons in every direction, but to communicate with neurons, they can be conductive at the tip only, Kemere said. “We take insulation for granted. But coating a nanotube thread with something that will maintain its integrity and block ions from coming in along the side is nontrivial,” he said.

    Sushma Sri Pamulapati, a graduate student in Pasquali’s lab, developed a method to coat a carbon nanotube fiber and still keep it between 15 to 30 microns wide, well below the width of a human hair. “Once we knew the size of the fiber, we fabricated the device to match it,” Robinson said. “It turned out we could make the exit channel two or three times the diameter of the electrode without having a lot of fluid come through.”

    2
    Rice University researchers have developed a method using microfluidics to implant conductive, thin, flexible fibers into brain tissue. Implanted wires could help patients with neurological diseases and help scientists explore cognitive processes and develop implants to help people to see, to hear and to control artificial limbs. Click on the image for a larger version. Courtesy of the Robinson Lab.

    The researchers said their technology may eventually be scaled to deliver into the brain at once multiple microelectrodes that are closely packed; this would make it safer and easier to embed implants. “Because we’re creating less damage during the implantation process, we might be able to put more electrodes into a particular region than with other approaches,” Robinson said.

    Flavia Vitale, a Rice alumna and now a research instructor at the University of Pennsylvania, and Daniel Vercosa, a Rice graduate student, are lead authors of the paper. Co-authors are postdoctoral fellow Alexander Rodriguez, graduate students Eric Lewis, Stephen Yan and Krishna Badhiwala and alumnus Mohammed Adnan of Rice; postdoctoral researcher Frederik Seibt and Michael Beierlein, an associate professor of neurobiology and anatomy at McGovern Medical School at the University of Texas Health Science Center at Houston; and Gianni Royer-Carfagni, a professor of structural mechanics at the University of Parma, Italy.

    Robinson and Kemere are assistant professors of electrical and computer engineering and adjunct assistant professors at Baylor College of Medicine. Pasquali is a professor of chemical and biomolecular engineering, of materials science and nanoengineering and of chemistry and chair of Rice’s Department of Chemistry.

    Supporting the research are the Defense Advanced Research Projects Agency, the Welch Foundation, the National Science Foundation, the Air Force Office of Scientific Research, the American Heart Association, the National Institutes of Health, the Citizens United for Research in Epilepsy Taking Flight Award and the Dan L. Duncan Family Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 8:13 am on October 23, 2017 Permalink | Reply
    Tags: Antennas, , “Specific radiation efficiency”, , , Nanotube fiber antennas as capable as copper, , Rice University   

    From Rice: “Nanotube fiber antennas as capable as copper” 

    Rice U bloc

    Rice University

    October 23, 2017
    Mike Williams

    1
    Rice University graduate student Amram Bengio sets up a nanotube fiber antenna for testing. Scientists at Rice and the National Institute of Standards and Technology have determined that nanotube fibers made at Rice can be as good as copper antennas but 20 times lighter. Photo by Jeff Fitlow

    Rice researchers show their flexible fibers work well but weigh much less

    Fibers made of carbon nanotubes configured as wireless antennas can be as good as copper antennas but 20 times lighter, according to Rice University researchers. The antennas may offer practical advantages for aerospace applications and wearable electronics where weight and flexibility are factors.

    The research appears in Applied Physics Letters.

    The discovery offers more potential applications for the strong, lightweight nanotube fibers developed by the Rice lab of chemist and chemical engineer Matteo Pasquali. The lab introduced the first practical method for making high-conductivity carbon nanotube fibers in 2013 and has since tested them for use as brain implants and in heart surgeries, among other applications.

    The research could help engineers who seek to streamline materials for airplanes and spacecraft where weight equals cost. Increased interest in wearables like wrist-worn health monitors and clothing with embedded electronics could benefit from strong, flexible and conductive fiber antennas that send and receive signals, Pasquali said.

    The Rice team and colleagues at the National Institute of Standards and Technology (NIST) developed a metric they called “specific radiation efficiency” to judge how well nanotube fibers radiated signals at the common wireless communication frequencies of 1 and 2.4 gigahertz and compared their results with standard copper antennas. They made thread comprising from eight to 128 fibers that are about as thin as a human hair and cut to the same length to test on a custom rig that made straightforward comparisons with copper practical.

    “Antennas typically have a specific shape, and you have to design them very carefully,” said Rice graduate student Amram Bengio, the paper’s lead author. “Once they’re in that shape, you want them to stay that way. So one of the first experimental challenges was getting our flexible material to stay put.”

    2
    Bengio prepares a sample nanotube fiber antenna for evaluation. The fibers had to be isolated in Styrofoam mounts to assure accurate comparisons with each other and with copper. Photo by Jeff Fitlow

    Contrary to earlier results by other labs (which used different carbon nanotube fiber sources), the Rice researchers found the fiber antennas matched copper for radiation efficiency at the same frequencies and diameters. Their results support theories that predicted the performance of nanotube antennas would scale with the density and conductivity of the fiber.

    “Not only did we find that we got the same performance as copper for the same diameter and cross-sectional area, but once we took the weight into account, we found we’re basically doing this for 1/20th the weight of copper wire,” Bengio said.

    “Applications for this material are a big selling point, but from a scientific perspective, at these frequencies carbon nanotube macro-materials behave like a typical conductor,” he said. Even fibers considered “moderately conductive” showed superior performance, he said.

    Although manufacturers could simply use thinner copper wires instead of the 30-gauge wires they currently use, those wires would be very fragile and difficult to handle, Pasquali said.

    “Amram showed that if you do three things right — make the right fibers, fabricate the antenna correctly and design the antenna according to telecommunication protocols — then you get antennas that work fine,” he said. “As you go to very thin antennas at high frequencies, you get less of a disadvantage compared with copper because copper becomes difficult to handle at thin gauges, whereas nanotubes, with their textile-like behavior, hold up pretty well.”

    Co-authors of the paper are, from Rice, graduate students Lauren Taylor and Peiyu Chen, alumnus Dmitri Tsentalovich and Aydin Babakhani, an associate professor of electrical and computer engineering, and, from NIST in Boulder, Colo., postdoctoral researcher Damir Senic, research engineer Christopher Holloway, physicist Christian Long, research scientists David Novotny and James Booth and physicist Nathan Orloff. Pasquali is a professor of chemical and biomolecular engineering, of materials science and nanoengineering and of chemistry.

    The U.S. Air Force supported the research.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 1:03 pm on August 18, 2017 Permalink | Reply
    Tags: , , Hot spot at Hawaii? Not so fast, Hot spots around the globe can be used to determine how fast tectonic plates move, , Paleogeography, Rice University, Seamounts, The Pacific Plate moves relative to the hot spots at about 100 millimeters per year   

    From Rice: “Hot spot at Hawaii? Not so fast” 

    Rice U bloc

    Rice University

    August 18, 2017
    Mike Williams

    Rice University scientists’ model shows global mantle plumes don’t move as quickly as thought

    Through analysis of volcanic tracks, Rice University geophysicists have concluded that hot spots like those that formed the Hawaiian Islands aren’t moving as fast as recently thought.

    Hot spots are areas where magma pushes up from deep Earth to form volcanoes. New results from geophysicist Richard Gordon and his team confirm that groups of hot spots around the globe can be used to determine how fast tectonic plates move.

    1
    Rice University geophysicists have developed a method that uses the average motion of hot-spot groups by plate to determine that the spots aren’t moving as fast as geologists thought. For example, the Juan Fernandez Chain (outlined by the white rectangle) on the Nazca Plate west of Chile was formed by a hot spot now at the western end of the chain as the Nazca moved east-northeast relative to the hotspot forming the chain that includes Alejandro Selkirk and Robinson Crusoe islands. The white arrow shows the direction of motion of the Nazca Plate relative to the hot spot, and it is nearly indistinguishable from the direction predicted from global plate motions relative to all the hot spots on the planet (green arrow). The similarity in direction indicates that very little motion of the Juan Fernandez hot spot relative to other hot spots is needed to explain its trend. Illustration by Chengzu Wang.

    Gordon, lead author Chengzu Wang and co-author Tuo Zhang developed a method to analyze the relative motion of 56 hot spots grouped by tectonic plates. They concluded that the hot-spot groups move slowly enough to be used as a global reference frame for how plates move relative to the deep mantle. This confirmed the method is useful for viewing not only current plate motion but also plate motion in the geologic past.

    The study appears in Geophysical Research Letters.

    Hot spots offer a window into the depths of Earth, as they mark the tops of mantle plumes that carry hot, buoyant rock from deep Earth to near the surface and produce volcanoes. These mantle plumes were once thought to be straight and stationary, but recent results suggested they can also shift laterally in the convective mantle over geological time.

    The primary evidence of plate movement relative to the deep mantle comes from volcanic activity that forms mountains on land, islands in the ocean or seamounts, mountain-like features on the ocean floor. A volcano forms on a tectonic plate above a mantle plume. As the plate moves, the plume gives birth to a series of volcanoes. One such series is the Hawaiian Islands and the Emperor Seamount Chain; the youngest volcanoes become islands while the older ones submerge. The series stretches for thousands of miles and was formed as the Pacific Plate moved over a mantle plume for 80 million years.

    The Rice researchers compared the observed hot-spot tracks with their calculated global hot-spot trends and determined the motions of hot spots that would account for the differences they saw. Their method demonstrated that most hot-spot groups appear to be fixed and the remainder appear to move slower than expected.

    “Averaging the motions of hot-spot groups for individual plates avoids misfits in data due to noise,” Gordon said. “The results allowed us to say that these hot-spot groups, relative to other hot-spot groups, are moving at about 4 millimeters or less a year.

    “We used a method of analysis that’s new for hot-spot tracks,” he said. “Fortunately, we now have a data set of hot-spot tracks that is large enough for us to apply it.”

    For seven of the 10 plates they analyzed with the new method, average hot-spot motion measured was essentially zero, which countered findings from other studies that spots move as much as 33 millimeters a year. Top speed for the remaining hot-spot groups — those beneath the Eurasia, Nubia and North America plates — was between 4 and 6 millimeters a year but could be as small as 1 millimeter per year. That’s much slower than most plates move relative to the hot spots. For example, the Pacific Plate moves relative to the hot spots at about 100 millimeters per year.

    Gordon said those interested in paleogeography should be able to make use of the model. “If hot spots don’t move much, they can use them to study prehistorical geography. People who are interested in circum-Pacific tectonics, like how western North America was assembled, need to know that history of plate motion.

    “Others who will be interested are geodynamicists,” he said. “The motions of hot spots reflect the behavior of mantle. If the hot spots move slowly, it may indicate that the viscosity of mantle is higher than models that predict fast movement.”

    “Modelers, especially those who study mantle convection, need to have something on the surface of Earth to constrain their models, or to check if their models are correct,” Wang said. “Then they can use their models to predict something. Hot-spot motion is one of the things that can be used to test their models.”

    Gordon is the W.M. Keck Professor of Earth Science. Wang and Zhang are Rice graduate students. The National Science Foundation supported the research.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 12:33 pm on July 15, 2017 Permalink | Reply
    Tags: , , , Iinspiration comes from advances in semiconductor manufacturing, , , Provide an alternate path for sight and sound to be delivered directly to the brain, Rice team developing flat microscope for the brain, Rice University, Will focus first on vision   

    From Rice: “Rice team developing flat microscope for the brain” 

    Rice U bloc

    Rice University

    July 12, 2017
    Mike Williams

    1
    Rice University engineers have built a lab prototype of a flat microscope they are developing as part of DARPA’s Neural Engineering System Design project. The microscope will sit on the surface of the brain, where it will detect optical signals from neurons in the cortex. The goal is to provide an alternate path for sight and sound to be delivered directly to the brain. (Credit: Rice University)

    Rice University engineers are building a flat microscope, called FlatScope [TM], and developing software that can decode and trigger neurons on the surface of the brain.

    Their goal as part of a new government initiative is to provide an alternate path for sight and sound to be delivered directly to the brain.

    The project is part of a $65 million effort announced this week by the federal Defense Advanced Research Projects Agency (DARPA) to develop a high-resolution neural interface. Among many long-term goals, the Neural Engineering System Design (NESD) program hopes to compensate for a person’s loss of vision or hearing by delivering digital information directly to parts of the brain that can process it.

    Members of Rice’s Electrical and Computer Engineering Department will focus first on vision. They will receive $4 million over four years to develop an optical hardware and software interface. The optical interface will detect signals from modified neurons that generate light when they are active. The project is a collaboration with the Yale University-affiliated John B. Pierce Laboratory led by neuroscientist Vincent Pieribone.

    Current probes that monitor and deliver signals to neurons — for instance, to treat Parkinson’s disease or epilepsy — are extremely limited, according to the Rice team. “State-of-the-art systems have only 16 electrodes, and that creates a real practical limit on how well we can capture and represent information from the brain,” Rice engineer Jacob Robinson said.

    Robinson and Rice colleagues Richard Baraniuk, Ashok Veeraraghavan and Caleb Kemere are charged with developing a thin interface that can monitor and stimulate hundreds of thousands and perhaps millions of neurons in the cortex, the outermost layer of the brain.

    “The inspiration comes from advances in semiconductor manufacturing,” Robinson said. “We’re able to create extremely dense processors with billions of elements on a chip for the phone in your pocket. So why not apply these advances to neural interfaces?”

    Kemere said some teams participating in the multi-institution project are investigating devices with thousands of electrodes to address individual neurons. “We’re taking an all-optical approach where the microscope might be able to visualize a million neurons,” he said.

    That requires neurons to be visible. Pieribone’s Pierce Lab is gathering expertise in bioluminescence — think fireflies and glowing jellyfish — with the goal of programming neurons with proteins that release a photon when triggered. “The idea of manipulating cells to create light when there’s an electrical impulse is not extremely far-fetched in the sense that we are already using fluorescence to measure electrical activity,” Robinson said.

    The scope under development is a cousin to Rice’s FlatCam, developed by Baraniuk and Veeraraghavan to eliminate the need for bulky lenses in cameras. The new project would make FlatCam even flatter, small enough to sit between the skull and cortex without putting additional pressure on the brain, and with enough capacity to sense and deliver signals from perhaps millions of neurons to a computer.

    Alongside the hardware, Rice is modifying FlatCam algorithms to handle data from the brain interface.

    “The microscope we’re building captures three-dimensional images, so we’ll be able to see not only the surface but also to a certain depth below,” Veeraraghavan said. “At the moment we don’t know the limit, but we hope we can see 500 microns deep in tissue.”

    “That should get us to the dense layers of cortex where we think most of the computations are actually happening, where the neurons connect to each other,” Kemere said.

    A team at Columbia University is tackling another major challenge: The ability to wirelessly power and gather data from the interface.

    In its announcement, DARPA described its goals for the implantable package. “Part of the fundamental research challenge will be developing a deep understanding of how the brain processes hearing, speech and vision simultaneously with individual neuron-level precision and at a scale sufficient to represent detailed imagery and sound,” according to the agency. “The selected teams will apply insights into those biological processes to the development of strategies for interpreting neuronal activity quickly and with minimal power and computational resources.”

    “It’s amazing,” Kemere said. “Our team is working on three crazy challenges, and each one of them is pushing the boundaries. It’s really exciting. This particular DARPA project is fun because they didn’t just pick one science-fiction challenge: They decided to let it be DARPA-hard in multiple dimensions.”

    Baraniuk is the Victor E. Cameron Professor of Electrical and Computer Engineering. Robinson, Veeraraghavan and Kemere are assistant professors of electrical and computer engineering.

    See the full article here .

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    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
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