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  • richardmitnick 4:00 pm on August 12, 2016 Permalink | Reply
    Tags: , Caltech, Mechanical chains made of soft matter that can transmit signals across long distances,   

    From Caltech: “The Utility of Instability” 

    Caltech Logo

    Caltech

    08/08/2016
    Robert Perkins
    (626) 395-1862
    rperkins@caltech.edu

    1
    A 3-D–printed logic gate with bistable elements linked together by springs to transmit signals. Credit: Dennis Kochmann/Caltech

    A team of researchers from Caltech and Harvard has designed and created mechanical chains made of soft matter that can transmit signals across long distances. Because they are flexible, the circuits could be used in machines such as soft robots or lightweight aircraft constructed from pliable, nonmetallic materials.

    Unlike hard materials, which transit signals readily, soft materials tend to absorb energy as it passes through them. An analogy is hitting a firm punching bag versus a soft one: with the firm bag, the energy of your punch moves through the bag and sends it swinging, but the soft bag deforms your fist like a lump of dough and therefore will swing less.

    To overcome that response, Caltech’s Dennis Kochmann, Chiara Daraio, and their colleagues created an unstable, “nonlinear” system. Their findings have appeared in three papers published over the past few months.

    “Engineers tend to shy away from instability. Instead, we take advantage of it,” says Kochmann, assistant professor of aerospace in the Division of Engineering and Applied Sciences, and one of the lead researchers on the project.

    Stable, or “linear,” systems are attractive to engineers because they are easy to model and predict. Take, for example, a spring: If you push on a spring, it will respond by pushing back with a force that is linearly proportional to how much force you apply. The response of a nonlinear system to that same push, by comparison, is not proportional, and can include sudden changes in the direction or amplitude of the responsive force.

    The nonlinear systems that Kochmann and his colleagues designed rely on bistable elements, or elements that can be stable in two distinct states. The bistable elements that the team developed consist of arches of an elastic material, each a few millimeters in size. The elements can be in either a convex or a concave position—and are stable in either configuration. However, if you push on the element in its convex position, it responds by pushing back against the direction of force until it snaps into a concave position, accompanied by a sudden release of energy in the opposite direction.

    “It’s an elastic response, and then a snap-through,” explains Daraio, professor of aeronautics and applied physics.

    Collaborating with Katia Bertoldi, Jennifer Lewis, and Jordan Raney of Harvard University, Kochmann, Daraio, and Caltech graduate student Neel Nadkarni designed chains of the bistable elements, connected to one another by springs. When one link “pops” from the concave to the convex state, its spring tugs at the link that is next downstream in the chain, popping it to a convex position as well. The signal travels unidirectionally down the chain. The energy released by the popping balances out any energy absorbed by the soft material, allowing the process to continue down the chain across long distances and at constant speed.

    A proof-of-concept version of the design constructed from 3-D printed elements is described in a paper published August 8, 2016 in the Proceedings of the National Academy of Sciences. This paper was the third in the series of publications outlining the new concept for transmitting signals. It outlined how the design can be used to build mechanical AND and OR logic gates such as those used in computer processors. Logic gates are the building blocks of circuits, allowing signals to be processed.

    “These systems could be used as actuators to control robotic limbs, while passively performing simple logic decisions,” Daraio says. Actuators use the transfer of energy to perform mechanical work, and in this case, the transfer of energy would occur via a mechanical rather than an electrical system.

    The first paper in the series was published in March in the journal Physical Review B, and it described Kochmann’s theoretical, mathematical framework for the system. The second paper was published in Physical Review Letters in June, and it describes Daraio’s first experimental model for the system.

    While springs can be employed between the bistable elements, the team also demonstrated in the Physical Review Letters paper how magnets could be used to connect the elements—potentially allowing the chain to be reset to its original position with a reversal of polarity.

    “Though there are many applications, the fundamental principles that we explore are most exciting to me,” Kochmann says. “These nonlinear systems show very similar behavior to materials at the atomic scale but these are difficult to access experimentally or computationally. Now we have built a simple macroscale analogue that mimics how they behave.”

    The PNAS paper is titled Stable propogation of mechanical signals in soft media using stored elastic energy. The authors are Nadkarni, Daraio, and Kochmann of Caltech and Jordan Raney, Jennifer Lewis, and Katia Bertoldi of Harvard University. The work was funded by the National Science Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

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    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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  • richardmitnick 3:54 pm on August 10, 2016 Permalink | Reply
    Tags: , , Caltech, Exploration & Collaboration,   

    From Caltech: “Exploration & Collaboration: The JPL-Caltech Connection” 

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    Caltech

    08/10/2016
    Lori Dajose

    Caltech’s partnership with NASA’s Jet Propulsion Laboratory has made possible countless discoveries about our universe—how and why black holes flare, where the water on Mars went, and how Earth’s carbon cycle works, just to name a few. Current Caltech faculty are participants on 12 missions.

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    See the full article here .

    Please help promote STEM in your local schools.

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    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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  • richardmitnick 2:45 pm on August 9, 2016 Permalink | Reply
    Tags: , , Caltech, Fiona Harrison,   

    From Caltech: Women in Science – “Fiona Harrison Honored with Massey Award” 

    Caltech Logo

    Caltech

    08/09/2016
    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Fiona Harrison

    Fiona Harrison, principal investigator of NASA’s NuSTAR (Nuclear Spectroscopic Telescope Array) mission, has been selected to receive the 2016 Massey Award, given by the Committee on Space Research (COSPAR).

    NASA/NuSTAR
    NASA/NuSTAR

    Harrison is Caltech’s Benjamin M. Rosen Professor of Physics and the Kent and Joyce Kresa Leadership Chair of the Division of Physics, Mathematics and Astronomy.

    The Massey Award, given in honor of the memory of Sir Harrie Massey, a mathematical physicist who served as the Physical Secretary of the Royal Society of London and a member of the COSPAR Bureau, recognizes “outstanding contributions to the development of space research in which a leadership role is of particular importance,” according to the COSPAR website.

    NuSTAR launched in June 2012, opening a new window to the universe as the first focusing telescope to operate in a high-frequency band of X-rays called hard X-rays. The observatory’s accomplishments include the creation of the first map of radioactive material in a supernova remnant; the discovery of emission from a special type of neutron star called a magnetar, which has an extremely strong magnetic field; and the detection of the brightest pulsar ever recorded.

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    This is the first map of radioactivity in a supernova remnant, the blown-out bits and pieces of a massive star that exploded. The blue color shows radioactive material mapped in high-energy X-rays using NuSTAR. Image credit: NASA/JPL-Caltech/CXC/SAO

    “These and many other discoveries make Fiona Harrison one of the most active leaders of modern high energy astrophysics,” the award citation notes.

    “It has been great to work with such a strong and talented team on NuSTAR,” says Harrison. “The whole team deserves credit in NuSTAR’s success.”

    Harrison has been the principal investigator since the mission was founded in 2005. After earning a doctoral degree in physics from UC Berkeley, she first came to Caltech in 1993 as a research fellow and began her professorial career at the Institute in 1995.

    Among other honors, Harrison received the NASA Outstanding Public Leadership medal in 2013 and the 2015 Rossi Prize for high-energy astrophysics. She was elected to the National Academy of Sciences in 2014.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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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  • richardmitnick 6:48 am on July 29, 2016 Permalink | Reply
    Tags: , , Caltech, , Team of Proteins Works Together to Turn on T Cells   

    From Caltech: “Team of Proteins Works Together to Turn on T Cells” 

    Caltech Logo

    Caltech

    07/15/2016
    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Researchers imaged cells to identify proteins that affect the expression of a genetic switch for T cells. On the right, T cells where the switch is activated glow in yellow. On the left, the rainbow pattern, a hierarchical cluster analysis, tells researchers which genes are controlled by the switch. The horizontal stripes are the genes. If they stripes turn red going from left to right, it means they are turning on; if they turn blue, the genes are turning off. Credit: Caltech

    The fates of various cells in our bodies—whether they become skin or another type of tissue—are controlled by genetic switches. In a new study, Caltech scientists investigate the switch for T cells, which are immune cells produced in the thymus that destroy virus-infected cells and cancers. The researchers wanted to know how cells make the choice to become T cells.

    “We already know which genetic switch directs cells to commit to becoming T cells, but we wanted to figure out what enables that switch to be turned on,” says Hao Yuan Kueh, a postdoctoral scholar at Caltech and lead author of a Nature Immunology report about the work, published on July 4.

    The study found that a group of four proteins, specifically DNA-binding proteins known as transcription factors, work in a multi-tiered fashion to control the T-cell genetic switch in a series of steps. This was a surprise because transcription factors are widely assumed to work in a simultaneous, all-at-once fashion when collaborating to regulate genes.

    The results may ultimately allow doctors to boost a person’s T-cell population. This has potential applications in fighting various diseases, including AIDS, which infects mature T cells.

    “In the past, combinatorial gene regulation was thought to involve all the transcription factors being required at the same time,” says Kueh, who works in the lab of Ellen Rothenberg, Caltech’s Albert Billings Ruddock Professor of Biology. “This was particularly true in the case of the genetic switch for T-cell commitment, where it was thought that a quorum of the factors working simultaneously was needed to ensure that the gene would only be expressed in the right cell type.”

    The authors report that a key to their finding was the ability to image live cells in real-time. They genetically engineered mouse cells so that a gene called Bcl11b—the key switch for T cells—would express a fluorescent protein in addition to its own Bcl11b protein. This caused the mouse cells to glow when the Bcl11b gene was turn on. By monitoring how different transcription factors, or proteins, affected the activation of this genetic switch in individual cells, the researchers were able to isolate the distinct roles of the proteins.

    The results showed that four proteins work together in three distinct steps to flip the switch for T cells. Kueh says to think of the process as a team of people working together to get a light turned on. He says first two proteins in the chain (TCF1 and GATA3) open a door where the main light switch is housed, while the next protein (Notch) essentially switches the light on. A fourth protein (Runx1) controls the amplitude of the signal, like sliding a light dimmer.

    “We identify the contributions of four regulators of Bcl11b, which are all needed for its activation but carry out surprisingly different functions in enabling the gene to be turned on,” says Rothenberg. “It’s interesting—the gene still needs the full quorum of transcription factors, but we now find that it also needs them to work in the right order. This makes the gene respond not only to the cell’s current state, but also to the cell’s recent developmental history.”

    Team member Kenneth Ng, a visiting student from California Polytechnic State University, says he was surprised by how much detail they could learn about gene regulation using live imaging of cells.

    “I had read about this process in textbooks, but here in this study we could pinpoint what the proteins are really doing,” he says.

    The next step in the research is to get a closer look at precisely how the T cell genetic switch itself works. Kueh says he wants to “unscrew the panels” of the switch and understand what is physically going on in the chromosomal material around the Bcl11b gene.

    The Nature Immunology paper, titled, Asynchronous combinatorial action of four regulatory factors activates Bcl11b for T cell commitment, includes seven additional Caltech coauthors: Mary Yui, Shirley Pease, Jingli Zhang, Sagar Damle, George Freedman, Sharmayne Siu, and Michael Elowitz; as well as a collaborator at the Fred Hutchinson Cancer Research Center, Irwin Bernstein. The work at Caltech was funded by a CRI/Irvington Postdoctoral Fellowship, the National Institutes of Health, the California Institute for Regenerative Medicine, the Al Sherman Foundation, and the Louis A. Garfinkle Memorial Laboratory Fund.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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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  • richardmitnick 3:26 pm on June 30, 2016 Permalink | Reply
    Tags: , Caltech, Sensing seizmic activity   

    From Caltech: “Community Seismic Network Detected Air Pulse From Refinery Explosion” 

    Caltech Logo

    Caltech

    06/30/2016

    Robert Perkins
    (626) 395-1862
    rperkins@caltech.edu

    1
    Models of mode shapes for building motion Credit: Image courtesy of M. Kohler/Caltech

    Tight network of low-cost detectors improve resolution of seismic data gathering and could offer city inspectors crucial information on building damage after a quake.

    On February 18, 2015, an explosion rattled the ExxonMobil refinery in Torrance, causing ground shaking equivalent to that of a magnitude-2.0 earthquake and blasting out an air pressure wave similar to a sonic boom.

    Traveling at 343 meters per second—about the speed of sound—the air pressure wave reached a 52-story high-rise in downtown Los Angeles 66 seconds after the blast.

    The building’s occupants probably did not notice a thing; the building shifted at most three-hundredths of a millimeter in response. But the building’s seismometers—one is installed on every floor, as well as on the basement levels—noted and recorded the motion of each individual floor.

    Those sensors are part of the Community Seismic Network (CSN), a project launched at Caltech in 2011 to seed the Los Angeles area with relatively inexpensive seismometers aimed at providing a high level of detail of how an earthquake shakes the Southern California region, as well as how individual buildings respond. That level of detail has the potential to provide critical and immediate information about whether the building is structurally compromised in the wake of an earthquake, says Caltech’s Monica Kohler, research assistant professor in the Division of Engineering and Applied Science.

    For example, if building inspectors know that inter-story drift—the displacement of each floor relative to the floors immediately below and above it—has exceeded certain limits based on the building’s size and construction, then it is a safe bet that the building has suffered damage in a quake. Alternately, if inspectors know that a building has experienced shaking well within its tolerances, it could potentially be reoccupied sooner—helping an earthquake-struck city to more quickly get back to normal.

    “We want first responders, structural engineers, and facilities engineers to be able to make decisions based on what the data say,” says Kohler, the lead author of a paper detailing the high-rise’s response that recently appeared in the journal Earthquake Spectra.

    The keys to the CSN’s success are affordability and ease of installation of its seismic detectors. Standard, high-quality seismic detectors can cost tens of thousands of dollars and need special vaults to house and protect them that can easily double the price. By contrast, the CSN detectors use $40 accelerometers and other off-the-shelf hardware, cost roughly $300 to build, and require minimal training to install. Approximately 700 of the devices have been installed so far, mostly in Los Angeles.

    However, the CSN sensors are roughly 250 times less sensitive than their more expensive counterparts, which is why the ability to successfully detect and quantify the downtown building’s response to the ExxonMobil explosion was such an important proof-of-concept.

    “It’s a validation of our approach,” says CSN’s project manager, Richard Guy.

    Sonic booms have been noted by seismic networks dozens of times before, beginning in the 1980s with the first detections of seismic shaking caused by space-shuttle reentries. The sonic booms, found Hiroo Kanamori and colleagues at Caltech and the United States Geological Survey, rattled buildings that, in turn, shook the ground around them.

    “Seismologists try to understand what is happening in the earth and how that affects buildings by looking at everything we see on seismograms,” says Kanamori, Caltech’s John E. and Hazel S. Smits Professor of Geophysics, Emeritus, and coauthor of the Earthquake Spectra paper. “In most cases, signals come from the interior of the earth, but nothing prevents us from studying signals from the air. Though rare, the signals from the air provide a new dimension in the field of seismology.”

    The earlier sonic boom detections were made using single-channel devices, which typically record motion in one direction only. While this information is useful for understanding ground shaking, a three-dimensional record of the floor-by-floor motion of a building can reveal how much a building is rocking, swaying, and shifting; two or more sensors installed per floor can show the twisting of the structure.

    “The more sensors you have in a small area, the more detail you’re going to see. If there are things happening on a small scale, you’ll never see it until you have sensors deployed on that scale,” Kohler says.

    Kohler and her colleagues found that the air pressure wave from the explosion had about the same impact on the high-rise as an 8 mile-per-hour gust of wind. A pressure wave about 100 times larger would have been required to have broken windows in the building; a wave 1,000 times larger would have been necessary to cause significant damage to the building.

    The ExxonMobil blast was not the first shaking recorded by the building’s seismometers. A number of earthquakes—including a magnitude-4.2 quake on January 4, 2015, with an epicenter in Castaic Lake, about 40 miles northwest of downtown Los Angeles—also were registered by the seismic detectors on nearly every floor of the building. But the refinery explosion-induced shaking was an important test of the sensitivity of the instruments, and of the ability of researchers to separate earthquake signals from other sources of shaking.

    Other authors of the Earthquake Spectra paper, “Downtown Los Angeles 52-Story High-Rise and Free-Field Response to an Oil Refinery Explosion,” include Caltech’s Anthony Massari, Thomas Heaton, Egill Hauksson, Robert Clayton, Julian Bunn, and K. M. Chandy. Funding for the CSN came from the Gordon and Betty Moore Foundation, the Terrestrial Hazard Observation and Reporting Center at Caltech, and the Divisions of Geological and Planetary Sciences and Engineering and Applied Science at Caltech.

    See the full article here .

    You can be a part of the Quake-Cathcer Network.

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    BOINCLarge

    BOINC WallPaper

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    Please help promote STEM in your local schools.

    STEM Icon

    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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  • richardmitnick 12:00 pm on June 20, 2016 Permalink | Reply
    Tags: , , Caltech, New exoplanet K2-33b   

    From Caltech: “Newborn Exoplanet Discovered Around Young Star” 

    Caltech Logo

    Caltech

    06/20/2016
    Lori Dajose

    1
    K2-33b, shown in this illustration, is one of the youngest exoplanets detected to date and makes a complete orbit around its star in about five days. These two characteristics combined provide exciting new directions for planet-formation theories. K2-33b could have formed on a farther out orbit and quickly migrated inward. Alternatively, it could have formed in situ, or in place. Credit: NASA/JPL-Caltech/R. Hurt

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    The K2-33 system and its planet in comparison to our own solar system. The planet is on a five-day orbit, whereas Mercury orbits our Sun in 88 days. The planet is also nearly ten times closer to its star than Mercury is to the Sun. Credit: NASA/JPL-Caltech

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    When a planet—such as K2-33b—passes in front of its host star, it blocks some of the star’s light. Detecting this periodic dimming, called a transit, from continual monitoring of a star’s brightness allows astronomers to detect planets outside of our solar system with a high degree of certainty. This Neptune-sized planet orbits a star that is between five and 10 million years old. In addition to the planet, the star hosts a disk of planetary debris, seen as a bright ring encircling the star. Credit: NASA/JPL-Caltech/R. Hurt

    Planet transit. NASA/Ames
    Planet transit. NASA/Ames

    Planet formation is a complex and tumultuous process that remains shrouded in mystery. Astronomers have discovered more than 3,000 exoplanets—planets orbiting stars other than our Sun—however, nearly all are middle-aged, with ages of a billion years or more. For astronomers, attempting to understand the life cycles of planetary systems using existing examples is like trying to learn how people grow from babies to children to teenagers, by only studying adults. Now, a team of Caltech-led researchers have discovered the youngest fully-formed exoplanet ever detected. The planet, K2-33b, at 5 to 10 million years old, is still in its infancy.

    The first signals of the planet’s existence were measured by NASA’s Kepler space telescope during its K2 mission. The telescope detected a periodic dimming in the light emitted by the planet’s host star—called K2-33—that hinted at the existence of an orbiting planet. Observations from the W.M. Keck Observatory in Hawaii validated that the dimming was indeed caused by a planet, later named K2-33b. A paper detailing the finding appears in the June 20 advance online issue of the journal Nature.

    “At 4.5 billion years old, the Earth is a middle-aged planet—about 45 in human-years,” says Trevor David, the first author on the paper and a graduate student working with professor of astronomy Lynne Hillenbrand. “By comparison, the planet K2-33b would be an infant of only a few weeks old.”

    “This discovery is a remarkable milestone in exoplanet science,” says Erik Petigura, a postdoctoral scholar in planetary science and a coauthor on the paper. “The newborn planet K2-33b will help us understand how planets form, which is important for understanding the processes that led to the formation of the earth and eventually the origin of life.”

    When stars form, they are encircled by dense regions of gas and dust, called protoplanetary disks, from which planets form. By the time a young star is a few million years old, this disk has largely dissipated and planet formation is mostly complete.

    The star orbited by K2-33b has a small amount of disk material left, indicated by observations from NASA’s Spitzer space telescope, demonstrating that it is in the final stages of dissipating. K2-33b was previously identified as a planet candidate in a survey of stars done with the K2 mission, the extended mission phase of the Kepler Space Telescope.

    “Astronomers know that star formation has just completed in this region, called Upper Scorpius, and roughly a quarter of the stars still have bright protoplanetary disks,” David says. “The remainder of stars in the region do not have such disks, so we reasoned that planet formation must be nearly complete for these stars, and that there would be a good chance of finding young exoplanets around them.”

    K2-33b, like many other exoplanets, was detected due to the periodic dimming in the central star’s light as the planet passes in front of it. By studying the frequency of dips in the star’s light and measuring by how much the light dimmed, the team was able to determine the size and orbital period of the planet. K2-33b is “a remarkable world,” according to Petigura. The exoplanet, which is about six times the size of Earth, or about 50 percent larger than Neptune, makes a complete orbit around its host star in about five days. This implies that it is 20 times closer to its star than Earth is to the Sun.

    K2-33b is a large planet like the gas giants in our solar system. In our solar system these giant planets are all far from the Sun. As it turns out, the proximity of the giant planet K2-33b to its star is not too out of the ordinary for planets in our galaxy—many have been discovered “close in,” often completing an orbit around their parent star in weeks or even days. The explanation for this is that large planets can be formed far from their star and migrate inward over time. The position of K2-33b so close to its parent star at such an early age implies that if migration occurred, it must have occurred quickly. Alternatively, the planet could be evidence against the migration theory, suggesting that giant planets can in fact form close in to their stars.

    “Discovering and studying K2-33b required using several of the most powerful astronomical instruments available, both in space and on Earth,” says Sasha Hinkley, now a senior lecturer at Exeter University and co-author on the study. As a NASA Sagan Postdoctoral Fellow at Caltech, Hinkley acquired data from the Keck telescope which was later used to help confirm the existence of the planet.

    K2-33b is fully formed, but it may still evolve over time. The next step is to measure the planet’s mass and determine its density. These measurements will offer insights into the planet’s fate later in life—whether it will stay roughly the same size or if it will cool and contract.

    “In the last 20 years, we have learned that nature can produce a staggering diversity of planets—from planets that orbit two stars to planets that complete a full orbit every few hours,” Petigura says. “We have much to learn, and K2-33b is giving us new clues.”

    The findings are detailed in a paper titled, A Neptune-sized transiting planet closely orbiting a 5–10 million-year-old star.” The work was supported by a National Science Foundation Graduate Research Fellowship and included data funded by NASA. Professor Lynne Hillenbrand, staff scientist David Ciardi, and senior faculty associate in astronomy Charles Beichman were additional Caltech coauthors on this paper.

    See the full article here .

    Please help promote STEM in your local schools.

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    Caltech campus
    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.”

     
  • richardmitnick 11:21 am on June 10, 2016 Permalink | Reply
    Tags: , , Caltech, Laura Shou, ,   

    From Caltech: Women in Science “Shou Receives Fellowship for Graduate Studies in Germany” Laura Shou 

    Caltech Logo
    Caltech

    06/09/2016
    Lori Dajose

    1
    Laura Shou. Credit: Courtesy of L. Shou

    Laura Shou, a senior in mathematics, has received a Graduate Study Scholarship from the German Academic Exchange Service (DAAD) to pursue a master’s degree in Germany. She will spend one year at the Ludwig-Maximilians-Universität München and the Technische Universität München, studying in the theoretical and mathematical physics (TMP) program.

    The DAAD is the German national agency for the support of international academic cooperation. The organization aims to promote international academic relations and cooperation by offering mobility programs for students, faculty, and administrators and others in the higher education realm. The Graduate Study Scholarship supports highly qualified American and Canadian students with an opportunity to conduct independent research or complete a full master’s degree in Germany. Master’s scholarships are granted for 12 months and are eligible for up to a one-year extension in the case of two-year master’s programs. Recipients receive a living stipend, health insurance, educational costs, and travel.

    “As a math major, I was especially interested in the TMP course because of its focus on the interplay between theoretical physics and mathematics,” Shou says. “I would like to use mathematical rigor and analysis to work on problems motivated by physics. The TMP course at the LMU/TUM is one of the few programs focused specifically on mathematical physics. There are many people doing research in mathematical physics there, and the program also regularly offers mathematically rigorous physics classes.”

    At Caltech, Shou has participated in the Summer Undergraduate Research Fellowship (SURF) program three times, conducting research with Professor of Mathematics Yi Ni on knot theory and topology, with former postdoctoral fellow Chris Marx (PhD ’12) on mathematical physics, and with Professor of Mathematics Nets Katz on analysis. She was the president of the Dance Dance Revolution Club and a member of the Caltech NERF Club and the Caltech Math Club.

    Following her year in Germany, Shou will begin the mathematics PhD program at Princeton.

    See the full article here .

    Please help promote STEM in your local schools.

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    Caltech campus

    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.”

     
  • richardmitnick 7:28 pm on June 8, 2016 Permalink | Reply
    Tags: , Caltech, ,   

    From Caltech: “Solving Molecular Structures” 

    Caltech Logo

    Caltech

    06/08/2016
    Lori Dajose

    1
    The various steps of the atomic structure determination by X-ray crystallography are shown from left to right: crystals of the green fluorescent protein variant mPlum; a single mPlum crystal X-ray diffraction pattern obtained at Caltech’s Molecular Observatory; the calculated electron density map (blue) interpreted with the the positioning of all mPlum polypeptide chain atoms (shown in ball-and-stick representation); and the entire atomic structure of mPlum shown in ribbon representation. Credit: Hoelz Laboratory/Caltech

    Determining the chemical formula of a protein is fairly straightforward, because all proteins are essentially long chains of molecules called amino acids. Each chain, however, folds into a unique three-dimensional shape that helps produce the characteristic properties and function of the protein. These shapes are more difficult to determine (or “solve”); scientists traditionally do so using a technique called X-ray crystallography, in which X-rays are shot through a crystallized sample and scatter off the atoms in a distinctive pattern.

    This spring, Caltech students had the opportunity to use the technique to solve protein structures themselves in a new course taught by Professor of Chemistry André Hoelz.

    Although the Institute has a long history in the fields of structural biology and X-ray crystallography, the chance to get hands-on experience with the technique is rare at most universities, Caltech included. Indeed, the method is more commonly performed at specialized facilities with high-energy X-ray beam lines, including the Stanford Synchrotron Radiation Laboratory (SSRL).

    SLAC/SSRL
    SLAC/SSRL

    However, in 2007, thanks to a gift from the Gordon and Betty Moore Foundation, Caltech opened the Molecular Observatory—a dedicated, completely automated radiation beam line at SSRL.

    1
    Graeme Card examines the sample mount holder in SSRL’s Molecular Observatory for Structural Molecular Biology at Beamline 12. (Courtesy: SLAC)

    “The Molecular Observatory gives us lots of beam time,” notes Hoelz. “Recently, I also received a grant from the Innovation in Education Fund from the Provost’s Office that was matched by the Division of Chemistry and Chemical Engineering, and this allowed me the opportunity to develop this course and train students in a way not commonly found at universities.”

    In the new course, “Macromolecular Structure Determination with Modern X-ray Crystallography Methods” (BMB/Ch 230), Hoelz’s students have been using the Molecular Observatory and other on-campus crystallization resources to solve the structures of various proteins, in particular, variants of green fluorescent proteins (GFPs)—proteins that exhibit bright green fluorescence under certain wavelengths of light. “These proteins are crucial tools in biology because they can be visualized by fluorescence techniques. It’s important to know their physical structure, because it affects the intensity and wavelength at which the protein fluoresces,” says Anders Knight, a first-year graduate student studying protein engineering with Frances Arnold, the Dick and Barbara Dickinson Professor of Chemical Engineering, Bioengineering and Biochemistry, and one of nine students—including two undergraduates—in the inaugural class.

    During the first few weeks of the course, students determined the proper conditions—the pH levels and the mix of salts and buffer solutions—that are required to get a protein to crystallize. These conditions vary from protein to protein, making it tricky to “grow” perfect single crystals of the proteins. “Most of the ones we are working with have known 3-D structures, and they crystallize relatively easily, so they are a great place to start learning about the technique of X-ray crystallography,” Knight says. “But some of us were also given protein variants that had never been crystallized before.”

    Once the students crystallized their proteins, single crystals were mounted in tiny nylon loops that are attached to small metal bases, frozen in liquid nitrogen, and loaded into pucks that were shipped to SSRL. There, the pucks were loaded into a robotic machine—remotely controllable from Caltech and operated by the students—that placed them, one by one, into a powerful X-ray beam. X-rays are scattered at characteristic angles by the electrons within the crystallized samples, generating a diffraction pattern that can be converted into a so-called electron-density map, which is then used to determine the 3-D location of all of the atoms.

    “The electron density map doesn’t exactly show you what the protein’s structure is,” Knight says. “You do have to correctly interpret the electron density map to determine where the protein’s atoms will go. It’s difficult, but this class is designed to give us practice doing that. Collecting data at SSRL was a great learning experience. It was interesting to be able to accurately mount and position the crystals—each smaller than a millimeter—on the beamline from hundreds of miles away. The data collection went fairly quickly, taking around eight minutes.”

    For their final assignment, students will write a mock journal paper about their methods and the final protein structure. Most of the structures had been determined previously, but one student did solve a previously unknown GFP structure, a bright red fluorescent protein called dTomato.

    “dTomato is a product of directed evolution in protein engineering, created by subjecting its parent, DsRed, through several rounds of random genetic mutations,” says Phong Nguyen, a graduate student in the lab of Doug Rees, Roscoe Gilkey Dickinson Professor of Chemistry and Howard Hughes Medical Institute Investigator, and the student who solved the structure of dTomato in Hoelz’s class. “By solving its structure, we can see how directed evolution—a method developed by Frances Arnold to create new proteins using the principles of evolution—changed the protein from its parent. Specifically, we are able to explain how individual mutations contributed to the structural outcome of the protein and consequently to differing chemical and physical properties from the parent. We all are so excited to solve a new structure and contribute knowledge to the field of GFP protein engineering.”

    “Having the Molecular Observatory at Caltech allows us to train students with very sophisticated technology,” says Hoelz, who is now envisioning a second, related course. “Students would learn recombinant protein expression and purification, directly prior to this course, so they can purify the proteins themselves with cutting-edge technology and then go on to determine their 3D structure by X-ray crystallography,” he says.

    “In my opinion, learning by doing is the best way to master how to determine crystal structures and this new course will solidify the strong roots Caltech has in X-ray crystallography,” Hoelz adds. “Not only will this new course accelerate the otherwise slow learning process for this technique, but it will also allow non-structural biology laboratories on campus to determine crystal structures of their favorite proteins using Molecular Observatory, a unique and spectacular facility at Caltech.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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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  • richardmitnick 3:59 pm on May 27, 2016 Permalink | Reply
    Tags: , Caltech, Majorana fermions,   

    From Caltech: “Engineering Nanodevices to Store Information the Quantum Way” 

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    Caltech

    05/27/2016
    Jessica Stoller-Conrad

    Creating quantum computers which some people believe will be the next generation of computers, with the ability to outperform machines based on conventional technology—depends upon harnessing the principles of quantum mechanics, or the physics that governs the behavior of particles at the subatomic scale. Entanglement—a concept that Albert Einstein once called “spooky action at a distance”—is integral to quantum computing, as it allows two physically separated particles to store and exchange information.

    1
    Stevan Nadj-Perge, assistant professor of applied physics and materials science. Credit: Photo courtesy of S. Nadj-Perge

    Stevan Nadj-Perge, assistant professor of applied physics and materials science, is interested in creating a device that could harness the power of entangled particles within a usable technology. However, one barrier to the development of quantum computing is decoherence, or the tendency of outside noise to destroy the quantum properties of a quantum computing device and ruin its ability to store information.

    Nadj-Perge, who is originally from Serbia, received his undergraduate degree from Belgrade University and his PhD from Delft University of Technology in the Netherlands. He received a Marie Curie Fellowship in 2011, and joined the Caltech Division of Engineering and Applied Science in January after completing postdoctoral appointments at Princeton and Delft.

    He recently talked with us about how his experimental work aims to resolve the problem of decoherence.

    What is the overall goal of your research?

    A large part of my research is focused on finding ways to store and process quantum information. Typically, if you have a quantum system, it loses its coherent properties—and therefore, its ability to store quantum information—very quickly. Quantum information is very fragile and even the smallest amount of external noise messes up quantum states. This is true for all quantum systems. There are various schemes that tackle this problem and postpone decoherence, but the one that I’m most interested in involves Majorana fermions. These particles were proposed to exist in nature almost eighty years ago but interestingly were never found.

    Relatively recently theorists figured out how to engineer these particles in the lab. It turns out that, under certain conditions, when you combine certain materials and apply high magnetic fields at very cold temperatures, electrons will form a state that looks exactly as you would expect from Majorana fermions. Furthermore, such engineered states allow you to store quantum information in a way that postpones decoherence.

    How exactly is quantum information stored using these Majorana fermions?

    The fascinating property of these particles is that they always come in pairs. If you can store information in a pair of Majorana fermions it will be protected against all of the usual environmental noise that affects quantum states of individual objects. The information is protected because it is not stored in a single particle but in the pair itself. My lab is developing ways to engineer nanodevices which host Majorana fermions. Hopefully one day our devices will find applications in quantum computing.

    Why did you want to come to Caltech to do this work?

    The concept of engineered Majorana fermions and topological protection was, to a large degree, conceived here at Caltech by Alexei Kiteav [Ronald and Maxine Linde Professor of Theoretical Physics and Mathematics] who is in the physics department. A couple of physicists here at Caltech, Gil Refeal [professor of theoretical physics and executive officer of physics] and Jason Alicea [professor of theoretical physics], are doing theoretical work that is very relevant for my field.

    Do you have any collaborations planned here?

    Nothing formal, but I’ve been talking a lot with Gil and Jason. A student of mine also uses resources in the lab of Harry Atwater [Howard Hughes Professor of Applied Physics and Materials Science and director of the Joint Center for Artificial Photosynthesis], who has experience with materials that are potentially useful for our research.

    How does that project relate to your lab’s work?

    There are two-dimensional, or 2-D, materials that are basically very thin sheets of atoms. Graphene—a single layer of carbon atoms—is one example, but you can create single layer sheets of atoms with many materials. Harry Atwater’s group is working on solar cells made of a 2-D material. We are thinking of using the same materials and combining them with superconductors—materials that can conduct electricity without releasing heat, sound, or any other form of energy—in order to produce Majorana fermions.

    How do you do that?

    There are several proposed ways of using 2-D materials to create Majorana fermions. The majority of these materials have a strong spin-orbit coupling—an interaction of a particle’s spin with its motion—which is one of the key ingredients for creating Majoranas. Also some of the 2-D materials can become superconductors at low temperatures. One of the ideas that we are seriously considering is using a 2-D material as a substrate on which we could build atomic chains that will host Majorana fermions

    What got you interested in science when you were young?

    I don’t come from a family of scientists; my father is an engineer and my mother is an administrative worker. But my father first got me interested in science. As an engineer, he was always solving something and he brought home some of the problems he was working. I worked with him and picked it up at an early age.

    How are you adjusting to life in California?

    Well, I like being outdoors, and here we have the mountains and the beach and it’s really amazing. The weather here is so much better than the other places I’ve lived. If you want to get the impression of what the weather in the Netherlands is like, you just replace the number of sunny days here with the number of rainy days there.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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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  • richardmitnick 4:46 pm on May 21, 2016 Permalink | Reply
    Tags: , Caltech, , The Power of Entanglement: A Conversation with Fernando Brandão   

    From Caltech: “The Power of Entanglement: A Conversation with Fernando Brandão” 

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    Caltech

    05/20/2016
    Written by Lori Dajose

    1
    Fernando Brandão. Credit: Courtesy of F. Brandão

    Computers are a ubiquitous part of modern technology, utilized in smartphones, cars, kitchen appliances, and more. But there are limits to their power. New faculty member Fernando Brandão, the Bren Professor of Theoretical Physics, studies how quantum computers may someday revolutionize computing and change the world’s cryptographic systems.

    What do you do?

    My research is in quantum information science, a field which seeks to merge two of the biggest discoveries of the last century: quantum mechanics and computer science. Particularly, I am interested in studying quantum entanglement.

    Entanglement is a special kind of correlations only found in quantum mechanics. We are all familiar with the concept of correlations. For example, the weather in Southern California is pretty well-correlated from one day to the next—if it is sunny today, it will likely be sunny tomorrow. Quantum systems can be correlated in an even stronger way. Entanglement was first seen as a weird feature of quantum mechanics—Einstein famously referred to it as a “spooky action at a distance.” But with the advancement of quantum information science, entanglement is now seen as a physical resource that can be used in information processing, such as in quantum cryptography and quantum computing. One part of my research is to develop methods to characterize and quantify entanglement. Another is to find new applications of entanglement, both in quantum information science and in other areas of physics.

    What is a quantum computer?

    At the most basic level, computers are made up of millions of simple switches called transistors. Transistors have two states—on or off—which can be represented as the zeroes or ones that make up binary code. With a quantum computer, its basic building blocks (called qubits) can be either a one or a zero, or they can simultaneously exist as a one and a zero. This property is called the superposition principle and, together with entanglement and quantum interference, it is what allows quantum computers to, theoretically, solve certain problems much faster than normal, or “classical,” computers could. It will take a long time until we actually have quantum computers, but we are already trying to figure out what they can do.

    What is an example of a problem only solvable by a quantum computer?

    It is a mathematical fact that any integer number can be factored into the product of prime numbers. For example, 21 can be written as 3 x 7, which are both prime numbers. Factoring a number is pretty straightforward when it is a small number, but factoring a number with a thousand digits would actually take a classical computer billions and billions of years—more time than the age of the universe! However, in 1994 Peter Shor showed that quantum computers would be so powerful that they would be able to factor numbers very quickly. This is important because many current cryptographic systems—the algorithms that protect your credit card information when you make a purchase online, for example—are based on factoring large numbers with the assumption that some codes cannot be cracked for billions of years. Quantum computing would change the way we do cryptography.

    What got you interested in quantum information?

    During my undergraduate education, I was looking online for interesting things to read, and found some lecture notes about quantum computation which turned out to be by Caltech’s John Preskill [Richard P. Feynman Professor of Theoretical Physics]. They are a beautiful set of lecture notes and they were really my first contact with quantum information and, in fact, with quantum mechanics. I have been working in quantum information science ever since. And now that I’m on the Caltech faculty, I have an office right down the hall from Preskill!

    What is your background?

    I am originally from Brazil. I did my bachelors and masters degrees there in physics, and my PhD at Imperial College London. After that, I moved among London, Brazil, and Switzerland for various postdocs. Then I became faculty at University College London. Last year I was working with the research group at Microsoft, and now I am here at Caltech. The types of problems I have worked on have varied with time, but they are all within quantum information theory. It is stimulating to see how the field has progressed in the past 10 years since I started working on it.

    What are you particularly excited about now that you are at Caltech?

    I can’t think of a better place than Caltech to do quantum information. There are many people working on it from different angles, for example, in the intersection of quantum information and condensed-matter physics, or high-energy physics. I am very excited that I get to collaborate with them.

    What do you like to do in your free time?

    I used to go traveling a lot, but six months ago my wife and I had a baby, so he is keeping us busy. Along with work and exercise, that basically takes up all my time.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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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