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  • richardmitnick 11:03 am on July 10, 2017 Permalink | Reply
    Tags: , , , eGaIn a liquid alloy of indium and gallium, Magnetic Liquid Metals, The Earth's liquid outer core made of iron is crucial to creating Earth’s magnetic field, University of Maryland Three Meter dynamo experiment, Yale   

    From Yale: “Study of the Center of the Earth” 

    Yale University bloc

    Yale University

    June 30, 2017
    Sonia Wang

    Study of the Center of the Earth | Yale Scientific

    What would you do with two million dollars? Chances are dim that your first answer would be to build and buy enough liquid sodium to fill a three-meter radius spherical tank. But for some scientists, this investment—the University of Maryland Three Meter dynamo experiment—paid off, serving as a key step to understanding the age-old question of how Earth’s magnetic field is generated.

    Earth’s magnetic field not only shields us from the sun’s damaging radiation, but also helps us navigate the Earth. Geophysicists have long studied the magnetic field created by Earth’s liquid core, but attempts to re-create them in the lab have previously been unsuccessful due to the prohibitively high costs of building equipment to do so.

    However, in a study published in January[Physical Review Fluids], a team of Yale researchers in Mechanical Engineering Professor Eric Brown’s lab developed a method for producing liquid metal with improved magnetic properties. The researchers created a protocol to create these Magnetic Liquid Metals (MLM) after studying a suspension of magnetic iron particles in eGaIn, a liquid alloy of indium and gallium. Such a technique could enable researchers to conduct dynamo experiments, which model the generation of Earth’s magnetic field, on a far smaller size scale.

    Magnetic Field’s Liquid Beginnings

    By studying earthquakes as they travel through the planet, seismologists know that the Earth has a fluid outer core surrounding a solid iron inner core. The liquid outer core, made of iron, is crucial to creating Earth’s magnetic field and is an example of a magnetohydrodynamic (MHD) phenomenon—magnetic properties resulting from an electrically conductive fluid. Movement of the outer core in the presence of Earth’s magnetic field induces electrical currents, which then create their own magnetic field aligning with Earth’s overall magnetic field. This process sustains itself and allows for the maintenance of Earth’s magnetic field over the years.

    The Earth’s magnetic field is responsible for phenomenon such as the Northern Lights, which occurs when the sun’s radiation is deflected by the magnetic field and collides with atmospheric particles. Image courtesy of Kristian Pikner, Wikimedia Commons.

    Magnetohydrodynamic phenomena only occur at a high magnetic Reynolds number, which describes the magnetohydrodynamic properties of an object; at a high Reynolds number, MHD phenomena are more likely. The magnetic Reynolds number depends on several properties, such as the system size, the fluid velocity, electrical conductivity, and magnetic susceptibility—the response of the fluid to a magnetic influence. Something as large as a planet would have an extremely high Reynolds number, making MHD phenomena more natural. However, re-creating such phenomena in a laboratory setting is extremely difficult, requiring materials with high magnetic and electrical properties.

    Traditional studies of MHD have used liquid metals and plasmas because they have the highest electric conductivities of any known materials. Liquid sodium has the highest conductivity and has been used to create a dynamo experiment in the past, but is both expensive and dangerous; sodium reacts explosively with water and needs to be heated above its high melting temperature. Looking for a safer and easier alternative, the researchers sought to use a different liquid metal base for the study.

    However, as noted before, other factors such as the magnetic susceptibility also affect the Reynolds number. Despite having a good electrical conductivity, pure eGaIn has a low magnetic susceptibility and therefore a low Reynolds number. To boost the Reynolds number, the researchers proposed creating a new material by suspending magnetic particles in liquid metals to increase their magnetic susceptibility and take advantage of the liquid metals natural high conductivity.

    Acid’s Key Role

    While scientists have previously attempted to suspend magnetic particles in liquid metals, they have not been very successful because of metallic oxidation. The oxidation of the metal causes a new “rusted” oxidation layer on the liquid metal, with its own set of properties. As this layer is more solid, it prevents some of the delicate suspension effects.

    eGaIn shows stronger magnetic properties than liquid sodium. Image courtesy of Florian Carle.

    Initially, stirring iron particles into the liquid eGaIn failed to create a successful suspension, since a solid oxide layer formed at the surface of the liquid upon exposure to air. Despite vigorous stirring to break the oxide skin, the particles clung to the oxide skin due to the strength of the interactions between the two layers.

    Seeking solutions to this problem, the scientists used hydrochloric acid (HCl), at a dangerously low pH of 0.69 capable of corroding skin, as a chemical cleaner or purifying agent; in eGaIn, hydrochloric acid removes the oxide layer on the liquid metal and iron particles, allowing for more liquid-like properties in the metal and increasing the conductivity of the iron particles. The suspension process was successful after the researchers added enough HCl to cover the metals and prevent further contact with air.

    Design Your Own Fluid

    The new material has increased magnetohydrodynamic properties compared to the original eGaIn. The resulting MLM had a Reynolds number over 5 times higher than that of pure liquid metal, or two times higher than liquid sodium. Thus, a dynamo experiment that would previously have required a three-meter radius tank might be possible on a much smaller size scale—10 square centimeters rather than three meters. “Until this study, no one thought about doing dynamo experiments with eGaIn because the quantity needed for these experiments make it cost prohibitive,” said Florian Carle, the lead author of the paper.

    Furthermore, certain properties of the MLM can be customized for different purposes and different applications. As long as the conductivity of the iron particles you would like to suspend is higher than that of the liquid metal base, nearly any material can be used for the liquid and suspended particles. “It’s basically Design Your Own Fluid…you can suspend silver, graphene, diamond…you can tune the size of the particles within this huge range,” Carle said. Changing the quantity of iron particles in eGaIn will modify the material viscosity—the more particles, the more viscous the fluid. Furthermore, changing the type of particle used can further affect the conductivity and magnetic properties of the material; using highly conductive particles will increase conductivity, and using magnetic particles like iron or steel can increase magnetic properties.

    The applications are myriad. Separately controlling the viscosity and the magnetic properties of the material will allow scientists to isolate the effects of magnetohydrodynamics, which is indicated by the Reynolds number, and turbulence, a measure affected by fluid viscosity and velocity that indicates how chaotic the flow of the material is.

    Carle designed the paper to be easily accessible, so that even a scientist without special training could re-create the material. He hopes that more scientists will apply the procedure to their research: “Now that we can tune the properties…hopefully people will start picking up on that and be able to use that. I hope in the near future we will see more and more experiments using MLMs,” Carle said.

    Of Sustainability and Superfluids

    Though Carle has moved on to work at the Yale Quantum Institute, research continues in the Brown lab on the material. One challenge the group is investigating is in keeping the magnetic liquid metals fresh during storage: after six months of storage, samples exhibited a loss in magnetic susceptibility as the hydrochloric acid slowly ate away at the iron particles.

    “It’s a bit of a conflict, since you need to protect the eGaIn with HCl, but then the HCl will eat the iron,” Carle said. Further research is being done to develop storage methods for eGaIn, including solidifying the samples or removing HCl to allow formation of a protective oxide layer on the surface of the fluid during storage.

    Carle further speculates that there are applications beyond MHD and dynamo experiments, since it is a customizable new material. And perhaps an MLM could eventually be created out of sodium, which has the highest electric conductivity of any known liquid metal. Adding magnetic particles to that suspension could allow scientists to attain a Reynolds number off the charts. “You would have a superfluid…maybe we would see phenomena we haven’t seen anywhere before,” Carle said.

    Featured Art by Isa del Toro Mijares

    See the full article here .

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    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

  • richardmitnick 11:49 am on July 7, 2017 Permalink | Reply
    Tags: , , , , Yale   

    From Yale: “A cosmic barbecue: Researchers spot 60 new ‘hot Jupiter’ candidates” 

    Yale University bloc

    Yale University

    July 6, 2017

    Jim Shelton


    Yale researchers have identified 60 potential new “hot Jupiters” — highly irradiated worlds that glow like coals on a barbecue grill and are found orbiting only 1% of Sun-like stars.

    Hot Jupiters constitute a class of gas giant planets located so close to their parent stars that they take less than a week to complete an orbit.

    Second-year Ph.D. student Sarah Millholland and astronomy professor Greg Laughlin identified the planet candidates via a novel application of big data techniques. They used a supervised machine learning algorithm — a sophisticated program that can be trained to recognize patterns in data and make predictions — to detect the tiny amplitude variations in observed light that result as an orbiting planet reflects rays of light from its host star.

    Millholland recently presented the research at a Kepler Science Conference at the NASA Ames Research Center in California. She and Laughlin are authors of a study about the research, which has been accepted for publication in the Astronomical Journal.

    The Yale technique pioneers a new discovery method that identifies more planets from the publicly available Kepler data, said the researchers.

    The Doppler velocity method is a well-established technique that enables the detection of wobbling motion in a star due to the gravitational influence of an orbiting planet. Since hot Jupiters are so massive and close to their stars, the stellar wobbles they induce are large and readily detectable.

    A new, Yale-designed instrument known as EXPRES, which is being installed on the Discovery Channel Telescope in Arizona, may attempt to make confirmations later this year.

    NSF funded Extreme Precision Spectrograph, EXPRES. The spectrograph will be commissioned at the Discovery Channel Telescope, part of the Lowell Observatory, near Flagstaff, Arizona

    Discovery Channel Telescope at Lowell Observatory, Happy Jack AZ, USA

    See the full article here .

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  • richardmitnick 9:50 am on July 3, 2017 Permalink | Reply
    Tags: , , Yale   

    From Yale: “Expanding the Quantum Computing Toolbox” 

    Yale University bloc

    Yale University

    January 17, 2017 [Just found this in social media.]
    Noah Kravitz

    In 2011, Canadian tech company D-Wave stunned the world by announcing that it would market a functioning quantum computer. Soon, companies ranging from Google to NASA bought versions of the device, and scientists began scrambling to evaluate what potentially was the biggest technological breakthrough of the century. One third-party test, in which the new quantum computer solved a complex math problem 3,600 times faster than a cutting-edge IBM supercomputer, seemed to substantiate D-Wave’s claims of quantum computation. Other tests found no evidence of quantum activity at all.

    Quantum computing, an idea which has captivated physicists and computer scientists alike since its conception in the 1980s, has proven difficult to realize in practice. Because quantum computers rely on the uncertainty built into the laws of quantum physics, they are extremely sensitive to their environments. A small imperfection in even a single component of the design can be devastating. One technical challenge is that heat energy can disrupt the fragile quantum states, so quantum technology is usually cooled almost to absolute zero (-273 degrees Celsius). D-Wave’s quantum computer is small enough to hold in the palm of your hand but has to be housed in a 10-foot-tall refrigerator.

    Yale researchers, led by Professor of Electrical Engineering and Physics Hong Tang, have developed a new version of a device called a piezo-optomechanical resonator that could allow quantum computers to operate at higher temperatures. The paper [Physical Review Letters], which is co-authored by graduate students Xu Han and Chang-Ling Zou, describes an improved method of connecting information in physical and electrical domains. This advance could be used as the basis for reliable memory storage for quantum computers—an important step towards stronger quantum computing.

    D-Wave’s putative quantum computer made headlines as possibly realizing decades’ worth of theoretical physics research. Here, qubits are assembled on a circuit board, much like the layout of a classical computer. Image courtesy of Wikipedia

    From Schrodinger’s cat to national security

    Quantum computing fundamentally differs from classical computing in that it relies on the non-intuitive quantum properties of light and matter. In familiar classical computation, information is stored as bits which can take on the values 0 and 1—they are simple on/off electrical switches, and it is easy to check their positions. The computer then performs tasks using sequences of logical operations on the bits. For example, it might say that if bit A is 0, then bit B should be set to 0, but if bit A is 1, then bit B should be set to 1; or that bit C should be set to 1 only if bits A and B are different.

    In quantum computing, by contrast, the situation is not so straightforward. First of all, information is stored in qubits (short for “quantum bits”) which have more than two possible values: 0, 1, and a combination of 0 and 1. These qubits are particles with distinct measurable quantum states corresponding to “0” and “1,” but one of the principles of quantum physics is that sometimes we can predict the result of a measurement only in terms of probabilities. So in quantum mechanics, even though sometimes we might know that we will always measure the particle as “0,” there can also exist a scenario in which there is a 50 percent chance of finding the particle in the “0” state and a 50 percent chance of finding it in the “1” state. The surprising part is that, mathematically speaking, the latter particle is actually in both states equally until we measure it as being in one or the other, and it is meaningful to think of such a qubit as having value ½ representing a “mixed” state even though ½ is not a possible measurement.

    Another useful property of quantum mechanics called entanglement links the measurements of different particles. For example, if particles A and B are entangled, then we might know that whenever we measure both particles, we will get one “0” and one “1.” In this case, measuring one qubit immediately determines the value of the other, and it is possible to use this property to “teleport” information!

    Unlike classical bits, which have only two possible values, qubits have a range of values from 0 to 1. In this common model of a qubit (where the North pole of the sphere represents the “0” state and the South pole the “1” state), the state of the qubit can be visualized as a point on the surface of the sphere. For instance, the value of any point above the equator is between 0 and ½, and the value of any point below the equator is between ½ and 1. Image courtesy of Columbia Science Review

    The unique logical underpinnings of quantum computation allow quantum computer to approach old problems in new ways. Since qubits are more complex than regular bits, quantum algorithms are often more streamlined than their classical counterparts, especially when searching for optimal solutions to problems. For example, if we want to find a car that is hidden behind one door out of a million, a classical computer would have to check the doors one by one, and, in the worst-case scenario, it would have to make a million queries. A quantum computer, by contrast, can use a probabilistic algorithm to find the car in at most only a thousand queries.

    Quantum computation has potential applications in many problems that would take classical computers longer than the age of the Earth. In the best-known example of this principle of “quantum speedup,” computer scientists have created a quantum algorithm that can factor large numbers (essentially a needle-in-a-haystack problem like the car example above) exponentially faster than is possible for any classical algorithm. Although this problem may not seem very exciting, it in fact underlies many more complex processes such as cryptography. Similar principles apply to choosing cost-effective combinations of building materials and even to identifying keywords for news articles. Unsurprisingly, quantum computation is often the best way to model complex natural systems.

    We have made significant progress over the past few decades towards meeting the challenges of quantum computing. As early as the mid-1990s, we have manipulated qubits and written codes to correct spontaneous errors in quantum computers. In the 2000s, we demonstrated long-distance entanglement. In 2013, Hong Tang and his team contributed to the corpus of knowledge when they determined a method for measuring quantum systems without permanently altering them. Now, in 2016, the Tang Lab at Yale has once again expanded the quantum computing toolbox, this time in the stubbornly challenging field of information storage and transfer.

    A new approach to quantum memory

    You probably carry around in your pocket a crucial piece of the new Yale device: Smartphones contain the materials that Tang and his team used to bridge the mechanical-electrical gap. Piezoelectrics are materials, usually crystals, that accumulate charge when compressed, twisted or bent. For instance, when a piezoelectric sheet is creased, a net negative charge forms at the fold, and net positive charges form at the ends. Conversely, when an external magnetic field causes charges in a piezoelectric to move, the object responds by changing shape physically. In this way, vibrations in physical objects and electrical fields can easily be connected, or, as physicists say, coupled. Piezoelectrics in smartphones often power tiny speakers— they convert electrical signals into sound waves, which arise from physical pulses.

    The Yale piezo-optomechanical device consists of a pair of tiny resonators: a silicon wafer and a wire loop situated above it. “It is useful to think of a resonator like a tuning fork because it responds most powerfully to a particular resonant frequency,” said Han, an electrical engineering Ph.D candidate who worked on the project. The two ends of the wire loop do not quite connect, so electrical charges tend to bounce back and forth around the circle, which functions as an electrical resonator in the microwave region of the electromagnetic spectrum. The wafer, which is about as thick as five sheets of paper, functions as an acoustic, or mechanical, resonator. This resonator is coated with a thin layer of aluminum nitride, a piezoelectric material, which facilitates the exchange of oscillations—and energy— between mechanical and electrical components. “If you want to transfer information between two systems, it is necessary to have an efficient coupling mechanism,” Han said.

    Professor Hong Tang (right) and graduate students Chang-Ling Zou (left) and Xu Han (not pictured) developed a piezo-optomechanical resonator that has applications to quantum memory storage. Image courtesy of Hong Tang

    The idea of coupling between mechanical and microwave electrical domains is not new; the Yale team’s innovation is achieving stronger coupling on a smaller scale. The key is using resonators with a higher frequency: Whereas other designs have used frequencies on the order of a few million oscillations per second, the Yale design runs at ten billion oscillations per second. As a result, the device is solidly in the so-called strong-coupling regime —meaning that the rate of information transfer is greater than the natural energy dissipation rates of the individual systems—and transmitted signals are clearer and longer-lasting. Yet high frequency comes at the cost of increased construction difficulties. “Since the device is small, it is more susceptible to perturbations in the environment,” Tang said. As a result, the design carefully balances considerations of compactness and robustness.

    The researchers believe that applications of their breakthrough lie mostly in the far future. “This is fundamental research, so it’s not immediately pertinent to daily life,” Han said. Instead, the piezo-optomechanical resonator’s real value is as a component of more complex systems. Because of the strong coupling achieved, it is well suited for quantum uses where “noise” from ambient heat (analogous to TV static) would otherwise be disruptive. “For high-frequency devices, the temperature requirement is not as low,” Han said. Chang-Ling Zou, a postdoctoral student in Tang’s lab, hopes to develop this strength into a basis for quantum memory storage, which is currently unfeasible at most temperatures. Small vibrating crystals would serve as physical memory, and the resonators would convert between these crystals and the computational part of the computer, which would likely operate in the microwave domain.

    The Yale team is also looking to incorporate visible light into their design. “The next step is integrating an optical resonator and using the acoustic resonator as an intermediary between microwave and optics,” Han said. Accomplishing this feat could improve computer signal processing, radio receiving efficiency, and information transmission across long distances via optical fiber cables.

    Given its versatility, the piezo-optomechanical resonator may find its way into all kinds of applications. From analyzing the stock market to sending trans-Atlantic messages, you can expect to hear more about this small device in big-time situations.

    See the full article here .

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  • richardmitnick 4:50 pm on June 28, 2017 Permalink | Reply
    Tags: , Transferring New Energy to an Old Rule: Pushing the Boundaries of Classical Physics, Yale   

    From Yale: “Transferring New Energy to an Old Rule: Pushing the Boundaries of Classical Physics” 

    Yale University bloc

    Yale University

    January 16, 2017
    Chunyang Ding

    Cover image: A synchrotron, similar to the one pictured above, was used to determine the composition of fossils, an analysis key to understanding the preservational features of the Tully Monster. Image courtesy of John O’Neill

    Time after time, brilliant scientists make claims about science’s future that prove completely wrong. In a quote often misattributed to Lord Kelvin, Albert Michelson famously declared that “there is nothing new to be discovered in physics now; all that remains is more and more precise measurement.” Classical mechanics, the tradition of physics that originated with Newton, Kepler, and Galileo, is often seen as something we already understand, and something we have understood for a long time. This is simply not true. Even today, new discoveries made with classical mechanics are transforming the world of science as we know it.

    In a recent breakthrough, a Yale physics lab shows new behaviors in a phenomenon that some had considered fully understood. Associate professor of physics Jack Harris and post-doctoral researcher Haitan Xu report in Nature their use of ultra-precise lasers and tiny vibrating sheets that appear to violate classical predictions. Their experiment, transferring energy by very slowly tuning the vibrations, has major implications for a decades-old theorem in mechanics: the adiabatic theorem. This newly discovered phenomenon occurs in all systems with friction, and may fundamentally shift the way physicists view systems.

    A dance for the ages

    Although Xu’s research focuses on how energy can be transferred between two different regions, the core of this new research deals with systems, a very general way of describing things that interact. Most things in the world are systems: the traffic through a busy city, the movement of the planets, or even a large ballroom dance.

    In a ballroom dance, each person on the dance floor obeys the rules of the dance, and as they move, they interact with other people harmoniously. There might be a set number of dance moves that eventually bring them back to the starting point. Essentially, Xu’s research found that there are certain moves that when danced “clockwise,” return you to the same position, but when danced “counter-clockwise,” present you with a new partner. This non-symmetrical form has serious implications for any system, and offers a new way that scientists could control these systems.

    Any system, even our solar system, can be represented in a parameter space, where different parameters are plotted against each other. Through careful control, the Harris lab was able to navigate the parameters of their vibrating membrane around an exceptional point, showing an extension to the adiabatic theorem. Image courtesy of Sida Tang

    The research provides an extension of the adiabatic theorem, a theorem that governs how systems change as the parameters of the systems change. These parameters can be any controlled quality of the system — the dance moves performed, the tension in a wire, or the controls in a computer. The adiabatic theorem says that if the parameters are slowly restored to their original state, the system will appear to have not changed at all. This is very powerful in physics, because for a certain experiment on a system, scientists can restore previous states without being concerned exactly in what way the parameters changed. Yet, it is not very exciting. After all, you only end up where you begin.

    Imagine for a moment that we had a small dial allowing us to change the masses of Jupiter and the Sun. Through our understanding of the laws of gravity, we could predict how the orbits of the planet change if Jupiter became more massive and if the Sun became less massive. The paths of the planets may become chaotic, but the adiabatic theorem provides a simple solution: when all of the parameters are back to where they began, the system would appear to have never changed.

    However, there is one caveat to the above examples. The only way that the adiabatic theorem has been proven is through assuming systems that do not have any friction, or energy loss. Only in those cases does the adiabatic theorem work as expected. Still, physicists applied this theorem to systems with friction by assuming such systems would behave very similarly to those without friction. What physicists did not expect, however, was that the system could change completely. Although mathematicians predicted anomalies using what they called “exceptional points,” physicists were unable to see these anomalies in actual systems — until now.

    Tiny vibrating membranes

    While the previous systems may be simple to imagine, they would be nearly impossible to actually control and measure. In order to actually see the effects of the adiabatic theorem, Xu’s research involved vibrating a tiny membrane between two mirrors while using lasers both to control and to measure the vibrations of the membrane. The reason this is considered a system is because the membrane has two vibrational modes, or methods of vibration, and the frequency of each vibration can be controlled by the laser. Vibrational modes are like vertical waves and a horizontal waves that pass by each other, and can be thought of as two separate strings, each vibrating independently.

    Vibrating strings are familiar to anyone who has played a string instrument, whether it be a guitar, a violin, or an erhu. When you pluck a single string, the other strings do not react, as each string has a different resonating frequency. However, if you tune two strings to have the same resonating frequency, the vibrating energy can transfer from one string to the other. In this experiment, the resonating frequencies are being changed so that the two different strings are first tuned together, and then returned to their original resonating frequencies. If we then apply the adiabatic theorem, we would predict that whatever vibrations are in the strings now are the same as the vibrations in the strings that we started with.

    The lab group, (Luyao Jiang, Haitan Xu, David Mason and Professor Jack Harris in 8, Professor Jack Harris, Haitan Xu, David Mason and Luyao Jiang in 9) pose before their experimental apparatus. Along with the Doppler group from the Vienna University of Technology, this lab was the first to discover experimental proof for the exceptional points. Image courtesy of George Iskander

    However, Xu’s research group discovered that this is not always the case in a system that has some amount of friction. In rare situations that involve the “exceptional point” in parameter space, the energy can end up transferring from the first string to the second string. Every time the parameters were changed counter-clockwise around the exceptional point, they found drastic changes to the final systems. They found that whenever the parameters created a path that encircled the exceptional point, this change happened, regardless of the actual shape of the path.

    Teleporting between different sheets

    Exceptional points are fairly difficult to imagine for a good reason: They are the result of two 2D sheets intersecting each other in a 4D space. One way to picture these exceptional points is a fire pole connecting two floors of a fire station. While each floor is distinct, they “meet” at the fire pole. However, oddly, when you walk counter-clockwise around the pole on the first floor, you would find yourself on the second floor, without having climbed the pole at all! The phenomenon here is due to the bizarre spatial geometry, similar to shapes like a Mobius strip or a Klein bottle. The exceptional points are mathematically similar, connecting surfaces that appear to be separated.

    The example with the fire station may be hard to visualize, but the actual experiment is even more abstract, as there is no actual movement around anything. Instead, when the parameters of the vibrations travel in this loop, the energy of the system shifts. The experimental group was able to quantitatively measure the energy differences in this single membrane by spying on the vibrations with a low-powered laser even as a high-powered laser changed the parameters. This research, the first of its type, provides solid evidence that the mathematicians were right: Exceptional points exist in parameter space, and physicists can utilize them to control the system.

    In the same issue of Nature, a separate group also published on this topic, but the group used a completely different method. While the Yale group was able to dynamically change the vibrations using the laser, a group from the Vienna University of Technology led by Jorg Doppler found similar effects through pre-fabricated waveguides, which are equally impressive in the ability to control waves. Together with the Xu research, these experiments provide the first empirical proof of exceptional points.

    Taking control of our world

    Like a Klein bottle, the geometries of parameter space may seem to be non-orientable, allowing for this phenomenon to occur. This bizarre discovery shows experimentally what was previously hypothesized mathematically. Image courtesy of Wikimedia

    The most powerful implication of this new research may be in its application for controlling systems. The adiabatic theorem, as well as this extension of the theorem, are particularly robust. They do not seem to care what path you take, as long as you return to the same position. This property is analogous to blindly driving through a dark two-lane icy tunnel, but finding that you always end up on the right side of the road at the end. These robust theorems are extremely helpful for experiments, especially in preventing disruptions to the system. “It’s a new type of control over really pristine systems,” Harris said.

    Even the classical adiabatic theorem and its offshoots are being used to predict magnetic effects and provide a deeper understanding for many quantum phenomena. This new extension of the adiabatic theorem will provide insight for physicists as they apply it to other systems, like NMRs and MRIs. In fact, this extended adiabatic theorem, as a fundamental physical theorem, could be more broadly applied to any system — so this research could theoretically be applied to anything that can be modeled as a system. However, this isn’t the end of the line on this research for the Harris lab; they have a paper forthcoming regarding the application of this technique to very different kinds of vibrations.

    Our understanding of every branch of science is constantly evolving and changing. Just when we think we understand everything about a field, we realize that particles can interact with themselves, that the fabric of space and time can stretch, and that the universe is expanding. Classical mechanics is no different; the extended adiabatic theorem from this study shows just that. At a certain point, we might as well expect to be surprised. If you find yourself walking around a fire pole on the first floor and ending up on the second, don’t be alarmed. Bizarre Twilight Zone scenarios like that are what can help physicist control, bend, and structure our world — no matter how strange those truths may be.

    See the full article here .

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  • richardmitnick 8:16 pm on June 8, 2017 Permalink | Reply
    Tags: , , Mammograms: Are we overdiagnosing small tumors?, , Yale   

    From Yale- “Mammograms: Are we overdiagnosing small tumors?” 

    Yale University bloc

    Yale University

    June 7, 2017

    Renee Gaudette
    (203) 671-8156

    (© stock.adobe.com)

    An analysis of breast cancer data revealed that many small breast cancers have an excellent prognosis because they are inherently slow growing, according to Yale Cancer Center experts. Often, these cancers will not grow large enough to become significant within a patient’s lifetime and subsequently early detection could lead to overdiagnosis, said the reseachers. In contrast, large tumors that cause most breast cancer deaths often grow so quickly that they become intrusive before they can be detected by screening mammography, they note.

    The study, published June 8 in the New England Journal of Medicine, questions the value of breast cancer early detection.

    “Our analysis explains both how mammography causes overdiagnosis and also why it is not more effective in improving outcomes for our patients. More importantly, it questions some of our fundamental beliefs about the value of early detection,” said Donald R. Lannin, M.D., professor of surgery at Yale School of Medicine and lead author on the paper.

    The research team analyzed invasive breast cancers diagnosed between 2001 and 2013 in the Surveillance, Epidemiology, and End Results (SEER) database and divided them into three prognostic groups based on biologic factors: grade, estrogen receptor (ER) status, and progesterone-receptor (PR) status. The three biologic categories were defined as favorable, intermediate, and unfavorable.

    The team, which also included Shiyi Wang, M.D., assistant professor of epidemiology at Yale School of Public Health, then used the expected rate of overdiagnosis of 22% to model the types of breast cancers and patient age ranges that likely account for the majority of overdiagnosis. The results showed that most overdiagnosis occurred in older patients with biologically favorable, slow-growing tumors.

    “Until now, we thought that the lead time, or time until a cancer becomes problematic for a patient, for most breast cancers was about three or four years. This paper shows that lead times vary widely depending on the tumor type. A large portion of aggressive cancers have a lead time of two years or less, whereas another large portion of breast cancers grow so slowly that the lead time is 15 to 20 years,” Lannin explained.

    “It is important that we educate physicians, patients, and the public on the indolent, slow-growing nature of some breast cancers. This knowledge will allow us to individualize treatment options, provide ‘personalized medicine,’ and avoid the major harms of overdiagnosis, which can result in overtreatment and the anxiety and fear that a cancer diagnosis causes,” Lannin said.

    See the full article here .

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    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

  • richardmitnick 6:19 am on April 25, 2017 Permalink | Reply
    Tags: , At Yale’s newest STEM labs teaching takes a bold step forward, , Yale   

    From Yale: “At Yale’s newest STEM labs, teaching takes a bold step forward” 

    Yale University bloc

    Yale University

    April 24, 2017

    Jim Shelton

    All photos by Michael Helfenbein

    At Sterling Chemistry Laboratory, students in an organic chemistry class learn a variety of skills that can be applied in research and industry.

    Even state-of-the-art laboratory fume hoods can’t contain the youthful exuberance spilling out of Christine DiMeglio’s organic chemistry class these days. It’s gotten to the point where, one day recently, a student stopped to give DiMeglio a friendly hug on the way out of the lab.

    The same vibrancy is also pouring forth from Iain Dawson’s microbiology class, Aruna Pawashe’s molecular biology classes, Stephen Irons’ physics classes — and throughout the newly renovated Sterling Chemistry Lab (SCL). Whether they’re isolating bacteria or chilling lasers, students are finding that an upgrade in the physical environment has led to an upgrade in learning.

    “In science, you look for the emergent properties,” said Dale Tager ’17, as he stepped away from his microscope in a second-floor biology lab at SCL. “Having a markedly better lab translates directly into having a better morale and a more cohesive environment for learning.”

    Christine DiMeglio (in red) talks with one of the students in her organic chemistry class.

    The faculty clearly concurs. “What we have now is an integrated science space,” said Jonathan Parr, who teaches general chemistry and inorganic chemistry on the third floor of SCL. “It’s a mood, and it’s meaningful. “We’re integrating the idea of being in the lab with the idea of being at the center of the university.”

    The new SCL, which debuted last September, has state-of-the-art labs for five Yale science departments: molecular biophysics & biochemistry; molecular, cellular and developmental biology; ecology and evolutionary biology; chemistry; and physics.

    Renovations to SCL encompassed 159,000 square feet, of which 31,600 is additional space. The result included not only the new teaching labs, but also an overhaul of mechanical systems and new lounge areas and student lockers.

    Meanwhile, Yale’s laboratory renaissance continues just down the hill on Prospect Street at the School of Engineering and Applied Science (SEAS).

    Coinciding with the opening of the new residential colleges in the fall, SEAS will open six new undergraduate teaching labs, along with two wet labs with fume hoods. The project brings together labs from all disciplines in engineering — currently scattered over four buildings — into one space.

    By having all the teaching labs together, students from different disciplines will have more chances to interact. For instance, a mechanical engineering major will be able to seek advice from a nearby electrical engineering student, or a chemical and environmental engineering study group will be able to borrow tools normally used in biomedical engineering.

    In addition to existing gear from current labs, the new labs will be outfitted with new equipment and computers. The labs also have collapsible walls to allow labs with a 24-student capacity to triple in size. Additional storage space and portable equipment will allow labs to be readily adapted for different courses from one semester to the next.

    Students collaborate on a class project in one of the physics labs in SCL.

    “This is an entirely new way of thinking about hands-on, interdisciplinary teaching,” said SEAS Dean T. Kyle Vanderlick. “It’s flexible, adaptive, and efficient. Students and faculty members from all disciplines will learn from each other and make the most of the full SEAS experience.”

    If the experience at SCL is any indication, it won’t take long for the benefits to take hold.

    Sparking the imagination

    The SCL physics labs, for example, are a veritable hive of scientific activity.

    It starts with Physics 205, a laboratory near the main hallway on the second floor. The room is outfitted with groupings of lab benches — all equipped with electrical and Internet capability — and drop-down power outlets on spindles attached to the ceiling, ready to power up projects.

    “Today I have them working on electricity and electric fields integration, how moving charges interact with magnetic fields,” explained Irons, who is the director of instructional labs for physics. “Last week we were studying oscilloscopes. We could just plug one into our AV projector and show everyone all of the features at once, rather than bringing it around to each table.”

    This room adjoins another lab where these students will continue their physics journey. Here, there are undergraduates investigating the principle of Fourier synthesis, working with superconductors, investigating x-ray diffraction, and getting to know their way around a small interferometer station. There are darkrooms, a seminar room, and a prep room where they can store tools and instructors can create new experiments.

    A series of curtained work areas and rooms devoted to advanced experiments adjoin this laboratory. Some students in this space are building a magneto-optical trap while others are conducting a quantum oscillation experiment. Meanwhile, small groups of faculty and students congregate and collaborate, including professor Steve Lamoreaux and associate professor Reina Maruyama.

    “You can really keep tabs on everyone here. It’s much more efficient — we’re no longer isolated,” Lamoreaux said. Noted Maruyama, “You can feel the energy here and hear the din of activity. The students are feeding off of each other and learning from one another, and they can look up and see what they’ll be doing next semester.”

    Students in Physics 205 studied how electricity and electric fields interact.

    They get to work on cutting-edge stuff, as well. In a corner room, Nir Navon, an assistant professor who arrived at Yale just a few months ago, is setting up an advanced lab that will produce a quantum gas in the next two years or so. Navon will divide the tasks so that students can be part of the process, learning new skills while gaining an understanding of what it is like to be involved in a major Yale physics project.

    “These experiments are all stepping stones to faculty research,” said senior lecturer Sidney Cahn, who oversees the advanced labs. “They spark the imagination.”

    A boost for biology

    In another part of SCL’s second floor, Dawson has wrapped up a microbiology lab session. His students (most of them will continue on to medical school) are taking off their white lab coats and clearing their workbenches.

    The lab layout is arranged in “islands,” to encourage student interaction. As befits a biology laboratory, there are neatly organized test tubes and beakers at the ready, as well as microscopes and refrigerators for storing samples.

    In this session, the students isolated bacteria from the human body and conducted a range of biochemical tests to identify the types of bacteria they found.

    Dawson said one of the advantages of a top-shelf biology laboratory is something students never see: the quality of the air. Especially during spring and autumn, airborne fungal spores might easily contaminate biological specimens and samples that students are working on in class. Having the latest air control technology safeguards those specimens.

    “It makes a huge difference,” Dawson said. “A great deal of thought has gone into everything here, right down to the windows that allow us to see our colleagues and classmates across the hall.”

    Lab adventures

    Back on the third floor of SCL, the air in DiMeglio’s organic chemistry lab includes a faint smell of bananas.

    This is because her students are at work making isopentyl acetate, or banana oil. One student weighs her banana oil product at the end of a reaction; another performs thin-layer chromatography on her purified banana oil; a third student completes the purification of his banana oil via distillation.

    Jonathan Tyson, a first-year graduate student, is a teaching assistant in chemistry.

    “Every day is an adventure in this lab,” DiMeglio said. “We’re preparing our students for the techniques and safety standards they’ll encounter in industry and research.”

    DiMeglio wears a red lab coat, identifying her as an instructor. The undergraduates around her wear white coats and graduate teaching assistants wear blue lab coats.

    Near a centrally located whiteboard, a group of students focuses on teaching assistant Jonathan Tyson, a first-year graduate student. He’s organized an in-class competition for students during a break from their isopentyl acetate work.

    “Here’s a good one,” Tyson said. “Can you define reflux? Can you also tell me why we use it?” The white coats go to work on the question, while Tyson takes a moment to tell a visitor what he likes best about the new Yale labs.

    “It’s the hoods,” he said, nodding toward one of the dozens of glass-enclosed fume hoods that fill the laboratory. “When you have the best equipment, you can do your best work.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

  • richardmitnick 12:25 pm on March 30, 2017 Permalink | Reply
    Tags: , , , Kepler-150 f, Yale   

    From Yale: “Finding a ‘lost’ planet, about the size of Neptune” 

    Yale University bloc

    Yale University

    March 29, 2017
    Jim Shelton

    An artist’s rendering of Kepler-150 f. (Illustration by Michael S. Helfenbein)

    Yale astronomers have discovered a “lost” planet that is nearly the size of Neptune and tucked away in a solar system 3,000 light years from Earth.

    The new planet, Kepler-150 f, was overlooked for several years. Computer algorithms identify most such “exoplanets,” which are planets located outside our solar system. The algorithms search through data from space mission surveys, looking for the telltale transits of planets orbiting in front of distant stars.

    But sometimes the computers miss something. In this case, it was a planet in the Kepler-150 system with a long orbit around its sun. Kepler-150 f takes 637 days to circle its sun, one of the longest orbits for any known system with five or more planets.

    The Kepler Mission found four other planets in the Kepler-150 system — Kepler-150 b, c, d, and e — several years ago. All of them have orbits much closer to their sun than the new planet does.

    “Only by using our new technique of modeling and subtracting out the transit signals of known planets could we then actually see it for what it really was,” said Joseph Schmitt, a graduate student at Yale and lead author of a new paper in The Astronomical Journal describing the planet. “Essentially, it was hiding in plain sight in a forest of other planetary transits.”

    Co-authors of the study are Yale astronomy professor Debra Fischer and Jon Jenkins of NASA’s Ames Research Center.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

  • richardmitnick 10:13 am on March 9, 2017 Permalink | Reply
    Tags: , , , Embryos can be repaired, in vitro fertilization, Triple helix, Yale   

    From Yale: “Gene editing opens the door to a “revolution” in treating and preventing disease” 

    Yale University bloc

    Yale University

    March 8, 2017
    John Dent Curtis

    Today, in vitro fertilization provides a way for couples to avoid passing potentially disease-causing genes to their offspring. A couple will undergo genetic screening. Tests will determine whether their unborn children are at risk. If embryos created through IVF show signs of such a genetic mutation, they can be discarded.

    Flash forward a few years, and, instead of being discarded, those embryos can be repaired with new gene editing technologies. And those repairs will affect not only those children, but all their descendants.

    “This is definitely new territory,” said Pasquale Patrizio, M.D., director of the Yale Fertility Center and Fertility Preservation Program. “We are at the verge of a huge revolution in the way disease is treated.”

    We are at the verge of a huge revolution in the way disease is treated.”
    Pasquale Patrizio, M.D., director of the Yale Fertility Center and Fertility Preservation Program

    In a move that seems likely to help clear the path for the use of gene editing in the clinical setting, on February 14 the Committee on Human Gene Editing, formed by the National Academy of Medicine and the National Academy of Sciences, recommended that research into human gene editing should go forward under strict ethical and safety guidelines. Among their concerns were ensuring that the technology be used to treat only serious diseases for which there is no other remedy, that there be broad oversight, and that there be equal access to the treatment. These guidelines provide a framework for discussion of technology that has been described as an “ethical minefield” and for which there is no government support in the United States.

    A main impetus for the committee’s work appears to be the discovery and widespread use of CRISPR-Cas9, a defense that bacteria use against viral infection. Scientists including former Yale faculty member Jennifer Doudna, Ph.D., now at the University of California, Berkeley, and Emmanuelle Charpentier, Ph.D., of the Max Planck Institute for Infection Biology in Berlin, discerned that the CRISPR enzyme could be harnessed to make precision cuts and repairs to genes. Faster, easier, and cheaper than previous gene editing technologies, CRISPR was declared the breakthrough of the year in 2015 by Science magazine, and has become a basic and ubiquitous laboratory research tool. The committee’s guidelines, said scientists, physicians, and ethicists at Yale, could pave the way for thoughtful and safe use of this and other human gene editing technologies. In addition to CRISPR, the committee described three commonly used gene editing techniques; zinc finger nucleases, meganucleases, and transcription activator-like effector nucleases.

    Patrizio, professor of obstetrics, gynecology, and reproductive sciences, said the guidelines are on the mark, especially because they call for editing only in circumstances where the diseases or disabilities are serious and where there are not alternative treatments. He and others cited such diseases as cystic fibrosis, sickle cell anemia, and thalassemia as targets for gene editing. Because they are caused by mutations in a single gene, repairing that one gene could prevent disease.

    Peter Glazer, M.D. ’87, Ph.D. ’87, HS ’91, FW ’91, chair and the Robert E. Hunter Professor of Therapeutic Radiology and professor of genetics, said, “The field will benefit from guidelines that are thoughtfully developed. This was a step in the right direction.”

    The panel recommended that gene editing techniques should be limited to deal with genes proven to cause or predispose to specific diseases. It should be used to convert mutated genes to versions that are already prevalent in the population. The panel also called for stringent oversight of the process and for a prohibition against use of the technology for “enhancements,” rather than to treat disease. “As physicians, we understand what serious diseases are. Many of them are very well known and well characterized on a genetic level,” Glazer said. “The slippery slope is where people start thinking about modifications in situations where people don’t have a serious disorder or disease.”

    Mark Mercurio, M.D., professor of pediatrics (neonatology), and director of the Program for Biomedical Ethics, echoed that concern. While he concurs with the panel’s recommendations, he urged a clear definition of disease prevention and treatment. “At some point we are not treating, but enhancing.” This in turn, he said, conjures up the nation’s own medical ethical history, which includes eugenics policies in the early 20th century that were later adopted in Nazi Germany. “This has the potential to help a great many people, and is a great advance. But we need to be cognizant of the history of eugenics in the United States and elsewhere, and need to be very thoughtful in how we use this technology going forward,” he said.

    The new technology, he said, can lead to uncharted ethical waters. “Pediatric ethics are more difficult,” Mercurio said. “It is one thing to decide for yourself–is this a risk I’m willing to take—and another thing to decide for a child. It is another thing still further, which we have never had to consider, to decide for future generations.”

    Myron Genel, M.D., emeritus professor of pediatrics and senior research scientist, served on Connecticut’s stem cell commission and four years on the Health and Human Services Secretary’s Advisory Committee on Human Research Protections. He believes that Connecticut’s guidelines on stem cell research provide a framework for addressing the issues associated with human gene editing. “There is a whole regulatory process that has been evolved governing the therapeutic use of stem cells,” he said. “There are mechanisms that have been put in place for effective local oversight and national oversight for stem cell research.”

    Although CRISPR has been the subject of a bitter patent dispute between Doudna and Charpentier and The Broad Institute in Cambridge, Mass., a recent decision by the U.S. Patent Trial and Appeal Board in favor of Broad is unlikely to affect research at Yale and other institutions. Although Broad, an institute of Harvard and the Massachusetts Institute of Technology, can now claim the patent, universities do not typically enforce patent rights against other universities over research uses.

    At Yale, scientists and physicians noted that gene editing is years away from human trials, and that risks remain. The issue now, said Glazer, is “How do we do it safely? It is never going to be risk-free. Many medical therapies have side effects and we balance the risks and benefits.” Despite its effectiveness, CRISPR is also known for what’s called “off-target risk,” imprecise cutting and splicing of genes that could lead to unforeseen side effects that persist in future generations. “CRISPR is extremely potent in editing the gene it is targeting,” Glazer said. “But it is still somewhat promiscuous and will cut other places. It could damage a gene you don’t want damaged.”

    Glazer has been working with a gene editing technology called triple helix that hijacks DNA’s own repair mechanisms to fix gene mutations. Triple helix, as its name suggests, adds a third strand to the double helix of DNA. That third layer, a peptide nucleic acid, binds to DNA and provokes a natural repair process that copies a strand of DNA into a target gene. Unlike CRISPR and other editing techniques, it does not use nucleases that cut DNA. “This just recruits a process that is natural. Then you give the cell this piece of DNA, this template that has a new sequence,” Glazer said, adding that triple helix is more precise than CRISPR and leads to fewer off-target effects, but is a more complex technology that requires advanced synthetic chemistry.

    Along with several scientists across Yale, Glazer is studying triple helix as a potential treatment for cystic fibrosis, HIV/AIDS, spherocytosis, and thalassemia.

    Adele Ricciardi, a student in her sixth year of the M.D./Ph.D. program, is working with Glazer and other faculty on use of triple helix to make DNA repairs in utero. She also supports the panel’s decision, but believes that more public discussion is needed to allay fears of misuse of the technology. In a recent presentation to her lab mates, she noted that surveys show widespread public concern about such biomedical advances. One study found that most of those surveyed felt it should be illegal to change the genes of unborn babies, even to prevent disease.

    “There is, I believe, a misconception of what we are using gene editing for,” Ricciardi said. “We are using it to edit disease-causing mutations, not to improve the intelligence of our species or get favorable characteristics in babies. We can improve quality of life in kids with severe genetic disorders.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

  • richardmitnick 3:15 pm on March 7, 2017 Permalink | Reply
    Tags: , , , Yale   

    From Yale: Women in STEM – “Yale-led team puts dark matter on the map” Priyamvada Natarajan 

    Yale University bloc

    Yale University

    March 1, 2017

    Jim Shelton

    Professor Priyamvada Natarajan

    Detailed map of reconstructed dark matter clump distributions in a distant galaxy cluster, obtained from the Hubble Space Telescope Frontier Fields data. The unseen matter in this map is comprised of a smooth heap of dark matter on which clumps form. No image credit.

    A Yale-led team has produced one of the highest-resolution maps of dark matter ever created, offering a detailed case for the existence of cold dark matter — sluggish particles that comprise the bulk of matter in the universe.

    The dark matter map is derived from Hubble Space Telescope Frontier Fields data of a trio of galaxy clusters that act as cosmic magnifying glasses to peer into older, more distant parts of the universe, a phenomenon known as gravitational lensing.

    Yale astrophysicist Priyamvada Natarajan led an international team of researchers that analyzed the Hubble images. “With the data of these three lensing clusters we have successfully mapped the granularity of dark matter within the clusters in exquisite detail,” Natarajan said. “We have mapped all of the clumps of dark matter that the data permit us to detect, and have produced the most detailed topological map of the dark matter landscape to date.”

    Scientists believe dark matter — theorized, unseen particles that neither reflect nor absorb light, but are able to exert gravity — may comprise 80% of the matter in the universe. Dark matter may explain the very nature of how galaxies form and how the universe is structured. Experiments at Yale and elsewhere are attempting to identify the dark matter particle; the leading candidates include axions and neutralinos.

    “While we now have a precise cosmic inventory for the amount of dark matter and how it is distributed in the universe, the particle itself remains elusive,” Natarajan said.

    Dark matter particles are thought to provide the unseen mass that is responsible for gravitational lensing, by bending light from distant galaxies. This light bending produces systematic distortions in the shapes of galaxies viewed through the lens. Natarajan’s group decoded the distortions to create the new dark matter map.

    Significantly, the map closely matches computer simulations of dark matter theoretically predicted by the cold dark matter model; cold dark matter moves slowly compared to the speed of light, while hot dark matter moves faster. This agreement with the standard model is notable given that all of the evidence for dark matter thus far is indirect, said the researchers.

    The high-resolution simulations used in the study, known as the Illustris suite, mimic structure formation in the universe in the context of current accepted theory. A study detailing the findings appeared Feb. 28 in the journal Monthly Notices of the Royal Astronomical Society.

    Other Yale researchers involved in the study were graduate students Urmila Chadayammuri and Fangzhou Jiang, faculty member Frank van den Bosch, and former postdoctoral fellow Hakim Atek. Additional co-authors came from institutions worldwide: Mathilde Jauzac from the United Kingdom and South Africa; Johan Richard, Eric Jullo, and Marceau Limousin from France; Jean-Paul Kneib from Switzerland; Massimo Meneghetti from Italy; and Illustris simulators Annalisa Pillepich, Ana Coppa, Lars Hernquist, and Mark Vogelsberger from the United States.

    The research was supported in part by grants from the National Science Foundation, the Science and Technology Facilities Council, and NASA via the Space Telescope Institute HST Frontier Fields initiative.

    The study can be found online.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

  • richardmitnick 11:27 am on March 6, 2017 Permalink | Reply
    Tags: , , , , , Laboratori Nazionali del Gran Sasso in Italy, , Women in STEM - "Meet the South Pole’s Dark Matter Detective" Reina Maruyama, Yale   

    From Nautilus: Women in STEM – “Meet the South Pole’s Dark Matter Detective” Reina Maruyama 



    Matthew Sedacca

    Reina Maruyama wasn’t expecting her particle detector to work buried deep in ice. She was wrong.

    In the late 1990s, a team of physicists at the Laboratori Nazionali del Gran Sasso in Italy began collecting data for DAMA/LIBRA, an experiment investigating the presence of dark matter particles.

    Gran Sasso LABORATORI NAZIONALI del GRAN SASSO, located in the Abruzzo region of central Italy

    DAMA/LIBRA at Gran Sasso
    DAMA/LIBRA at Gran Sasso

    The scientists used a scintillation detector to spot the weakly interactive massive particles, known as WIMPs, thought to constitute dark matter. They reported seeing an annual modulation in the number of “hits” that the detector receives. This was a potential sign that the Earth is moving through the galaxy’s supposed halo of dark matter—something that few, if any, researchers could claim.

    Reina Maruyama’s job, at a detector buried two-kilometers deep in the South Pole, is to determine whether or not these researchers’ findings are actually valid. Previously, Maruyama worked at the South Pole to detect neutrinos, the smallest known particle. But when it came to detecting dark matter, especially with using detectors buried under glacial ice, she was initially skeptical of the task. In those conditions, she “couldn’t imagine having it run and produce good physics data.”

    Contrary to Maruyama’s expectations, the detector’s first run went smoothly. Their most recent paper, published in Physical Review D earlier this year, affirmed the South Pole as a viable location for experiments detecting dark matter. The detector, despite the conditions, kept working. At the moment, however, “DM-Ice17,” as her operation is known, is on hiatus, with the team having relocated to Yangyang, South Korea, to focus on COSINE-100, another dark matter particle detector experiment, and continue the search for the modulation seen in DAMA/LIBRA.

    COSINE-100 Dark Matter Experiment – Yale University

    The shielding structure of COSINE-100 includes 3 cm of copper, 20 cm of lead, and 3 cm of 37 plastic scintillator panels for cosmic ray muon tagging. 18 5-inch PMTs are attached to the copper box to observe scintillation light from liquid scintillator, and each plastic scintillator has a 2-inch PMT attached on one side (top panels have a PMT on each side). http://cosine.yale.edu/about-us/cosine-100-experiment.

    Dark Matter?Data visuals from COSINE-100, a dark matter experiment in Yangyang, South Korea. Reina Maruyama

    Nautilus sat down with Maruyama at Yale this past January to talk about the potential nature of dark matter, the variety of ways scientists use to search for it, and what it’s like working in the South Pole.

    What do the scientists behind DAMA claim to have discovered?

    What this experiment with DAMA has seen is that in June, the velocity is odd. The sun and Earth are going in the same direction; in December, the velocities are in opposite directions, at about a 10 percent difference. That means in June we expect this signature to occur more frequently than in December. DAMA claims to have seen this annual modulation signature. People started to think about: “Well what is it that DAMA is seeing? Could it be some sort of environmental effect?” We don’t know. They’ve looked at their data, and they’ve argued against every possibility that people have come up with. One thing that the dark matter community has asked them to do is actually release their data, but so far they have refused to do that.

    The original idea of DM-Ice was to go to the southern hemisphere where the seasonal variation is opposite in phase, so if we continue to see the signal, then it would be really hard to attribute that signal to something seasonal. If we don’t see anything, then there is something in their data that they don’t understand.

    University of Wisconsin–Madison, DM-Ice collaborators

    So what is dark matter?

    We don’t know what it is. We know it exerts gravity. This is why we call it matter. We see evidence from it: in how stars move around in a galaxy, and galaxies around each other. When we look out at distant stars and galaxies, we can see light being bent around something that exerts gravity, even on photons, but we don’t see any light, x-rays, or clues of things existing.

    What we saw was that the speed of the rotating objects are much faster than what you would expect for something like that. So that seems to indicate there is more mass between these objects. You can do that by adding a clump of mass between. That’s what we see: not specific objects, but dark matter diffusely spread out all over, typically surrounding galaxies. There must be dark matter inside the orbit of our sun so that we can move at the speed that we are. That means we are going through this halo of dark matter, riding along with the sun and the earth.

    What can we do to prove that dark matter is causing these changes?

    Let’s just pick a volume, your coffee, right there. We are hypothesizing that if dark matter is WIMPs, then there’s a very small possibility that the WIMPs going at 300 kilometers per second could interact with the coffee nuclei. If that happens in our detectors, we can actually see a nucleus being kicked by a WIMP. That’s how a lot of particle detectors work: Either there are some energy transfers to the electrons, or there is some energy transfer into the nuclei, and then we detect the electrons or light emitted from that, or sound waves. If those occur at the right energy, with the right frequency, then we can say maybe we see dark matter in our detectors.

    When there is a knock into a nucleus you can actually collect two different kinds of signals: the charge and photon emissions. When nuclei get kicks, it transfers some of that energy into electrons, and then the electrons move around, and that process emits light, and in some of that, electrons can be collected, and that is a signal. You need some sort of mass, and you need to be able to tell if a nucleus got a kick. The most efficient way to do that is to have a detector that is also the target, where the nuclei is. You want some big volume to increase the likeliness this can occur. DAMA is using sodium iodide detectors. These are very sensitive experiments, and a lot of these can actually tell the difference between an initial electron kick versus an initial nuclear kick. The electron kicks actually occur much more often in these detectors, so you can reject those as background and just keep the nuclear kicks.

    Newer technologies are much more sensitive to nuclear kicks than sodium iodide. Every other experiment that has tried to look for a signature like this has not seen anything. They see nuclear kicks, but mostly attributable to neutrons. They cannot definitively say that this must be dark matter.

    Gamma Ray Shield, or Bath tub?Maruyama said, “We put detectors inside when we need to shield them from gamma rays that are present in a typical room. The box is made of lead bricks.” NO image credit.

    How did you come up with the design for your experiments?

    With DM-Ice, we wanted to be as similar to DAMA as possible: We want sodium iodide, and we want it to be low-background. So we need shielding around it to block the detector from gamma rays and cosmic rays. The only thing that’s changing should be the dark matter. It turns out the South Pole is actually a pretty good environment. You have an entire continent of ice, which is very stable. Once you go two and a half kilometers into the ice, nothing is changing. Ice at the South Pole, it’s super clean.

    Then you need to start worrying about practical things like: Can you get there, and do you have infrastructure to run the experiment? Is it affordable, do you have the right people to do this with? That starts to narrow down the site and the environment. You end up with the a few places in the world you could do this, and then maybe you want to partner with somebody else so that you can afford a bigger detector, and more, better infrastructure that’s more stable. That is the thinking process. Then you have to convince your colleagues in the field that this is a really good idea and need to share a pot of resources available to all U.S. funds. That’s the thought-process behind the experiment.

    What’s it like working in the South Pole?

    First you have to get approved to go, but that’s pretty competitive. A lot of people want to go and so if you have a good reason to go, you go. Before you go, you need to get medical clearance. You get checked out. It’s a remote location. They want to make sure you’re not gonna get sick while you’re there. So you spend one or two nights in Christchurch, New Zealand. You meet a lot of other people who might be going with you: engineers, geologists, biologists, other scientists, firemen, cooks, and bus drivers; a lot of really engaged and very passionate people.

    When you get to the South Pole, you have take it slow, even though you’re excited and working, it’s 10,000 feet, so they ask you to take it easy your first few days. You enter through what looks like a restaurant-refrigerator door. Keep the cold out kind of thing. Very comfortable, get your own room, dormitory-style living. Water is very precious. All of the energy is provided by jet fuel. So airplanes fly in and siphon off the fuel except for what’s needed for to get back. And there’s a power station where they generate electricity. They get water by melting the ice, and it’s a very expensive process. You get like two-minute showers twice a week. It’s on the honor system. That’s what it’s like living in the station.

    What are some problems that you faced when working down there?

    It’s 24/7 sunlight. So the sun circles above your head. Because you’re there to get things done, it’s hard to know when to stop working. But before you know it, it’s two in the morning, and the sun’s bright and shining. So you have to make sure you get enough sleep and ready to work the next day. That was a challenge for me.

    So when you’re not on site what are you doing in terms of research?

    We might have a small-scale detector here and do stress tests on it. Physicists love to tinker: How we can improve these detectors? What if we changed the temperature a lot? How can we make this detector even quieter so that we can look for even smaller signals, or a signal that exists that looks even bigger? People like to say things like we’re looking for a needle in a haystack, so can we reduce the haystack? Can we change the color of the haystack so that the needle looks even more visible?

    What’s the future for DM-Ice?

    Right now there is no drilling happening at the South Pole. We’ll keep pushing to do that experiment. In the meantime, the detector is buried and frozen into the ice, so we might as well just keep it running. We’re focusing on the Korean effort. What we can do there is look for the signal. If we continue to see the same signal, we can try to look for other correlations and cross them off on our own. If we cannot find other causes for it, I think the case for DAMA becomes stronger. Then DAMA’s signal is not specific to DAMA.

    See the full article here .

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