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  • richardmitnick 11:05 am on September 28, 2020 Permalink | Reply
    Tags: , "The testimony of trees: How volcanic eruptions shaped 2000 years of world history", , , University of Cambridge,   

    From University of Cambridge via phys.org- “The testimony of trees: How volcanic eruptions shaped 2000 years of world history” 

    U Cambridge bloc

    From University of Cambridge

    via


    phys.org

    September 28, 2020
    Sarah Collins, University of Cambridge

    1
    Driftwood in Siberia. Credit: University of Cambridge.

    Researchers have shown that over the past two thousand years, volcanoes have played a larger role in natural temperature variability than previously thought, and their climatic effects may have contributed to past societal and economic change.

    The researchers, led by the University of Cambridge, used samples from more than 9000 living and dead trees to obtain a precise yearly record of summer temperatures in North America and Eurasia, dating back to the year 1 CE. This revealed colder and warmer periods that they then compared with records for very large volcanic eruptions as well as major historical events.

    Crucial to the accuracy of the dataset was the use of the same number of data points across the entire 2000 years. Previous reconstructions of climate over this extended period have been biased by over-representation of trees from more recent times.

    The results, reported in the journal Dendrochronologia, show that the effect of volcanoes on global temperature changes is even greater than had been recognised, although the researchers stress that their work in no way diminishes the significance of human-caused climate change.

    Instead, the researchers say, the study contributes to our understanding of the natural causes and societal consequences of summer temperature changes over the past two thousand years.

    “There is so much we can determine about past climate conditions from the information in tree rings, but we have far more information from newer trees than we do for trees which lived a thousand years or more ago,” said Professor Ulf Büntgen from Cambridge’s Department of Geography, the study’s lead author. “Removing some of the data from the more recent past levels the playing field for the whole 2000-year period we’re looking at, so in the end, we gain a more accurate understanding of natural versus anthropogenic climate change.”

    Comparing the data from tree rings against evidence from ice cores, the researchers were able to identify the effect of past volcanic eruptions on summer temperatures.

    Large volcanic eruptions can lower global average temperatures by fractions of a degree Celsius, with strongest effects in parts of North America and Eurasia. The main factor is the amount of sulphur emitted during the eruption that reaches the stratosphere, where it forms minute particles that block some sunlight from reaching the surface. This can result in shorter growing seasons and cooler temperatures, that lead in turn to reduced harvests. Conversely, in periods when fewer large eruptions occurred, the Earth is able to absorb more heat from the Sun and temperatures rise.

    “Some climate models assume that the effect of volcanoes is punctuated and short,” said Büntgen. “However, if you look at the cumulative effect over a whole century, this effect can be much longer. In part, we can explain warm conditions during the 3rd, 10th and 11th centuries through a comparative lack of eruptions.”

    Reconstructed summer temperatures in the 280s, 990s and 1020s, when volcanic forcing was low, were comparable to modern conditions until 2010.

    Compared with existing large-scale temperature reconstructions of the past 1200-2000 years, the study reveals a greater pre-industrial summer temperature variability, including strong evidence for the Late Antique Little Ice Age (LALIA) in the 6th and 7th centuries.

    Then, working with historians, the scientists found that relatively constant warmth during Roman and medieval periods, when large volcanic eruptions were less frequent, often coincided with societal prosperity and political stability in Europe and China. However, the periods characterised by more prolific volcanism often coincided with times of conflict and economic decline.

    “Interpreting history is always challenging,” said Dr. Clive Oppenheimer, the lead volcanologist of the study. “So many factors come into play—politics, economics, culture. But a big eruption that leads to widespread declines in grain production can hurt millions of people. Hunger can lead to famine, disease, conflict and migration. We see much evidence of this in the historical record.

    “We knew that large eruptions could have these effects, especially when societies were already stressed, but I was surprised to see the opposite effect so clearly in our data—that centuries with rather few eruptions had warmer summers than the long-term average.”

    The new temperature reconstructions provide deeper insights into historical periods in which climactic changes, and their associated environmental responses, have had an outsized impact on human history. This has clear implications for our present and future. As climate change accelerates, extreme events, such as floods, drought, storms and wildfires, will become more frequent.

    “Humans have no effect on whether or not a volcano erupts, but the warming trend we are seeing right now is certainly related to human activity,” said Büntgen. “While nothing about the future is certain, we would do well to learn how climate change has affected human civilisation in the past.”

    See the full article here .

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    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 1:39 pm on September 21, 2020 Permalink | Reply
    Tags: "Astronomers discover the first ‘ultrahot Neptune’: one of nature’s improbable planets", , , , , LTT 9779 is a Sun-like star located at a distance of 260 light years- a stone’s throw in astronomical terms., LTT 9779 is metal-rich having twice the amount of iron in its atmosphere than the Sun., LTT 9779b exists in the ‘Neptunian Desert’- a region devoid of planets when we look at the population of planetary masses and sizes., , The planet orbits so close to its star that its year lasts only 19 hours., Ultra Short Period planets, University of Cambridge   

    From University of Cambridge- “Astronomers discover the first ‘ultrahot Neptune’: one of nature’s improbable planets” 

    U Cambridge bloc

    From University of Cambridge

    21 Sep 2020

    An international team of astronomers, including researchers from the University of Cambridge, has discovered a new class of planet, an ‘ultrahot Neptune’, orbiting the nearby star LTT 9779.

    1
    Artist’s impression of LTT 9779b. Credit: icardo Ramirez, Universidad de Chile.

    The planet orbits so close to its star that its year lasts only 19 hours, and stellar radiation heats the planet to over 1700 degrees Celsius.

    At these temperatures, heavy elements like iron can be ionised in the atmosphere and molecules disassociated, providing a unique laboratory to study the chemistry of planets outside the solar system.

    Although the planet weighs twice as much as Neptune, it is also slightly larger and has a similar density. Therefore, LTT 9779b should have a huge core of around 28 Earth masses, and an atmosphere that makes up around 9% of the total planetary mass.

    The system itself is around two billion years old, and given the intense irradiation, a Neptune-like planet would not be expected to keep its atmosphere for so long, providing a puzzle for astronomers to solve; how such an improbable system came to be. The results are reported in the journal Nature Astronomy.

    LTT 9779 is a Sun-like star located at a distance of 260 light years, a stone’s throw in astronomical terms. It is metal-rich, having twice the amount of iron in its atmosphere than the Sun. This could be a key indicator that the planet was originally a much larger gas giant, since these bodies tend to form close to stars with the highest iron abundances.

    Initial indications of the existence of the planet were made using the Transiting Exoplanet Survey Satellite (TESS), as part of its mission to discover small transiting planets orbiting nearby and bright stars across the whole sky.

    NASA/MIT TESS replaced Kepler in search for exoplanets.

    Planet transit. NASA/Ames.

    Such transits are found when a planet passes directly in front of its parent star, blocking some of the starlight, and the amount of light blocked reveals the companion’s size. Planets like these, once fully confirmed, can allow astronomers to investigate their atmospheres, providing a deeper understanding of planet formation and evolution processes.

    The transit signal was confirmed in early November 2018 as originating from a planetary mass body, using observations taken at the ESO la Silla Observatory in northern Chile.

    ESO/HARPS at La Silla.

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    HARPS uses the Doppler Wobble method to measure planet masses and orbital characteristics. When objects are found to transit, Doppler measurements can be organized to confirm the planetary nature in an efficient manner. In the case of LTT 9779b, the team were able to confirm the planet’s existence after only one week of observations.

    Professor James Jenkins from the Department of Astronomy at the Universidad de Chile, who led the team, said: “The discovery of LTT 9779b so early in the TESS mission was a complete surprise; a gamble that paid off. The majority of transit events with periods less than one day turnout to be false-positives, normally background eclipsing binary stars.”

    The planet was uncovered in only the second of 26 sectors of observations that TESS would be observing across the whole sky. Since no similar types of planets were detected in the TESS precursor missions Kepler and K2, the finding was even more exciting.

    “We selected this candidate from a TESS alert due to its very short orbital period. After inspecting the light curve, we found it was a good candidate for an upcoming week-long observation campaign using the HARPS spectrograph in La Silla,” said co-author Matías Díaz, also from the Universidad de Chile. “We planned the observations carefully, to maximize the use of the spectrograph and sample the orbit of the candidate in an optimal way. During the first nights of data we saw the observations matched the predicted period of the candidate. Further analysis of the seven nights of observations in November were consistent with a massive Neptune planet.”

    LTT 9779b exists in the ‘Neptunian Desert’, a region devoid of planets when we look at the population of planetary masses and sizes. Although icy giants seem to be a fairly common by-product of the planet formation process, this is not the case very close to their stars. The researchers believe these planets get stripped of their atmospheres over cosmic time, ending up as so-called Ultra Short Period planets.

    The Kepler mission found that Ultra Short Period planets, those that orbit their stars in one day or less, come mainly in the form of large gas giants or small rocky planets. Models tell us that planets like LTT 9779b should be stripped of their atmospheres through a process called photoevaporation as they move close to their stars. The large gas giants, on the other hand, have strong gravitational fields that can hold onto their atmospheres, and so we end up with a dearth of planets like Neptune with the shortest orbital periods.

    “Planetary structure models tell us that the planet is a giant core dominated world, but crucially, there should exist two to three Earth-masses of atmospheric gas,” said Jenkins. “But if the star is so old, why does any atmosphere exist at all? Well, if LTT 9779b started life as a gas giant, then a process called Roche Lobe Overflow could have transferred significant amounts of the atmospheric gas onto the star.”

    Roche Lobe Overflow is a process whereby a planet comes so close to its star that the star’s stronger gravity can capture the outer layers of the planet, causing it to transfer onto the star and so significantly decreasing the mass of the planet. Models predict outcomes similar to that of the LTT 9779 system, but they also require some fine-tuning.

    “It could also be that LTT 9779b arrived at its current orbit quite late in the day, and so hasn’t had time to be stripped of the atmosphere. Collisions with other planets in the system could have thrown it inwards towards the star. Indeed, since it is such a unique and rare world, more exotic scenarios may be plausible,” said Jenkins.

    Members of the Cambridge Astronomy department are part of the Next-Generation Transit Survey (NGTS). The NGTS team conducted follow-up observations of LT9779b’s transit to help confirm the planetary nature of the system and better constrain its properties.

    “LTT 9779b is an intriguing planet, being the first of its kind discovered,” said co-author Dr Ed Gillen, from Cambridge’s Cavendish Laboratory. “It is particularly exciting because of its peculiarity: how did this planet come to arrive on such a short period orbit and why does it still possess an atmosphere? Fortunately, the planetary system is located nearby so we can study it in detail, which promises new insights into how such planets come to be and what they are made of.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 1:06 pm on September 7, 2020 Permalink | Reply
    Tags: , "Study identifies limits on the efficiency of techniques for reducing noise in quantum resources", , Despite their huge potential most quantum systems are inherently susceptible to errors and noise., PI-Perimeter Institute of Theoretical Physics, Quantum technologies could thus soon help humans to tackle a variety of problems more efficiently., Quantum technologies such as quantum computers; quantum sensing devices; and quantum memory have often been found to outperform traditional electronics in speed and performance ., The findings improve the understanding of the fundamental principles of quantum mechanics., The new "no-purification" theorems they have introduced are expected to play critical roles in the scientific and practical development of quantum physics, They mathematically proved the existence of a series of universal limits on the accuracy and efficiency of methods to purify different types of quantum resources associated with practical applications, University of Cambridge, University of Cambridge U.K. and Perimeter Institute for Theoretical Physics tried to gain a theoretical understanding of the limitations of techniques for "purifying" noisy quantum resources.   

    From University of Cambridge and Perimeter Institute via phys.org: “Study identifies limits on the efficiency of techniques for reducing noise in quantum resources” 

    U Cambridge bloc

    From University of Cambridge

    Perimeter Institute
    Perimeter Institute

    via


    phys.org

    September 7, 2020
    Ingrid Fadelli

    1
    A drawing representing distillation—a fundamental subroutine for quantum technologies. Credit: Fang & Liu.

    Quantum technologies, such as quantum computers, quantum sensing devices and quantum memory, have often been found to outperform traditional electronics in speed and performance, and could thus soon help humans to tackle a variety of problems more efficiently. Despite their huge potential, most quantum systems are inherently susceptible to errors and noise, which poses a serious challenge to implementing and using them in real-world settings.

    To enable the large-scale implementation of quantum technologies, researchers have been trying to develop techniques that could make them more resilient to noise and less prone to errors. While some of these methods, such as quantum error correction and fault tolerance, have proved to be useful and are now cornerstones of quantum information science, the factors that limit the performance of quantum systems in real-world applications are still poorly understood.

    Researchers at University of Cambridge in the U.K. and Perimeter Institute for Theoretical Physics in Canada have recently tried to gain a theoretical understanding of the limitations of techniques for “purifying” noisy quantum resources. In a paper published in Physical Review Letters, they mathematically proved the existence of a series of universal limits on the accuracy and efficiency of methods to purify different types of quantum resources associated with practical applications, which play a key role in the functioning of quantum technologies.

    “The ideas and techniques discussed in our paper originate from the general ‘one-shot quantum resource theory,’ which we outlined in one of our earlier Physical Review Letters papers,” Zi-Wen Liu, one of the researchers who carried out the study, told Phys.org. “The key idea is to analyze an information-theoretic quantity called the quantum hypothesis testing relative entropy, which is shown to induce universal limitations on noisy-state to pure-state transformations.”

    2
    Credit: Fang & Liu.

    Using mathematical theorems, Liu and his colleagues proved a series of fundamental limitations on the extent to which generic noisy resources can be purified, which stem from the laws of quantum mechanics. The calculations they carried out apply to virtually all types of quantum resources.

    “More explicitly, we derive nontrivial lower bounds on the error of converting any full-rank noisy state to any target pure-resource state by any free protocol (including probabilistic ones)—and find that it is impossible to achieve perfect resource purification, even probabilistically,” Liu explained. “In particular, there is a nontrivial tradeoff bound between the success probability and the accuracy of the protocol, which is akin to an ‘uncertainty relation.'”

    The mathematical theorems introduced by this team of researchers imply the existence of strong limits to the efficiency of distillation, a technique to purify quantum resources that underpins a wide variety of blueprinted quantum technologies. More specifically, these theorems introduce the first explicit lower bounds on the costs of magic state distillation, which is considered to be a leading scheme for realizing scalable and fault-tolerant quantum computation.

    “Remarkably, our theorems allowed us to establish the first rigorous understanding of the necessary resource costs of large-scale quantum computing and other quantum technologies,” Liu said. “We expect that our results will serve as important guidelines and find wide-ranging applications in practical scenarios. Moreover, we are writing a follow-up work on extending the no-purification theorems to quantum channels, which are directly applicable to important dynamical scenarios like quantum channel simulation and circuit synthesis, to make the theory more complete.”

    In addition to shedding light on the costs and limitations of quantum technologies, the findings improve the understanding of the fundamental principles of quantum mechanics. Like the celebrated no-go theorems, the no-cloning theorem and the uncertainty principle, the new “no-purification” theorems they have introduced are expected to play critical roles in the scientific and practical development of quantum physics. In the future, they could spark further research into how well these limits can be achieved, ultimately paving the way to more efficient quantum technologies for practical real-world applications.

    See the full article here .

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    Stem Education Coalition

    Perimeter Institute is a leading centre for scientific research, training and educational outreach in foundational theoretical physics. Founded in 1999 in Waterloo, Ontario, Canada, its mission is to advance our understanding of the universe at the most fundamental level, stimulating the breakthroughs that could transform our future. Perimeter also trains the next generation of physicists through innovative programs, and shares the excitement and wonder of science with students, teachers and the general public.

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 11:34 am on July 29, 2020 Permalink | Reply
    Tags: "‘Quantum negativity’ can power ultra-precise measurements", Metrology is the science of estimations and measurements., , University of Cambridge   

    From University of Cambridge: “‘Quantum negativity’ can power ultra-precise measurements” 

    U Cambridge bloc

    From University of Cambridge

    29 Jul 2020
    Sarah Collins
    sarah.collins@admin.cam.ac.uk
    Communications team

    1
    Artist’s impression of a quantum metrology device. Credit:Hugo Lepage

    The researchers, from the University of Cambridge, Harvard and MIT, have shown that quantum particles can carry an unlimited amount of information about things they have interacted with. The results reported in the journal Nature Communications, could enable far more precise measurements and power new technologies, such as super-precise microscopes and quantum computers.

    Metrology is the science of estimations and measurements. If you weighed yourself this morning, you’ve done metrology. In the same way as quantum computing is expected to revolutionise the way complicated calculations are done, quantum metrology, using the strange behaviour of subatomic particles, may revolutionise the way we measure things.

    We are used to dealing with probabilities that range from 0% (never happens) to 100% (always happens). To explain results from the quantum world however, the concept of probability needs to be expanded to include a so-called quasi-probability, which can be negative. This quasi-probability allows quantum concepts such as Einstein’s ‘spooky action at a distance’ and wave-particle duality to be explained in an intuitive mathematical language. For example, the probability of an atom being at a certain position and travelling with a specific speed might be a negative number, such as –5%.

    An experiment whose explanation requires negative probabilities is said to possess ‘quantum negativity.’ The scientists have now shown that this quantum negativity can help take more precise measurements.

    All metrology needs probes, which can be simple scales or thermometers. In state-of-the-art metrology however, the probes are quantum particles, which can be controlled at the sub-atomic level. These quantum particles are made to interact with the thing being measured. Then the particles are analysed by a detection device.

    In theory, the greater number of probing particles there are, the more information will be available to the detection device. But in practice, there is a cap on the rate at which detection devices can analyse particles. The same is true in everyday life: putting on sunglasses can filter out excess light and improve vision. But there is a limit to how much filtering can improve our vision — having sunglasses which are too dark is detrimental.

    “We’ve adapted tools from standard information theory to quasi-probabilities and shown that filtering quantum particles can condense the information of a million particles into one,” said lead author Dr David Arvidsson-Shukur from Cambridge’s Cavendish Laboratory and Sarah Woodhead Fellow at Girton College. “That means that detection devices can operate at their ideal influx rate while receiving information corresponding to much higher rates. This is forbidden according to normal probability theory, but quantum negativity makes it possible.”

    An experimental group at the University of Toronto has already started building technology to use these new theoretical results. Their goal is to create a quantum device that uses single-photon laser light to provide incredibly precise measurements of optical components. Such measurements are crucial for creating advanced new technologies, such as photonic quantum computers.

    “Our discovery opens up exciting new ways to use fundamental quantum phenomena in real-world applications,” said Arvidsson-Shukur.

    Quantum metrology can improve measurements of things including distances, angles, temperatures and magnetic fields. These more precise measurements can lead to better and faster technologies, but also better resources to probe fundamental physics and improve our understanding of the universe. For example, many technologies rely on the precise alignment of components or the ability to sense small changes in electric or magnetic fields. Higher precision in aligning mirrors can allow for more precise microscopes or telescopes, and better ways of measuring the earth’s magnetic field can lead to better navigation tools.

    Quantum metrology is currently used to enhance the precision of gravitational wave detection in the Nobel Prize-winning LIGO Hanford Observatory. But for the majority of applications, quantum metrology has been overly expensive and unachievable with current technology. The newly-published results offer a cheaper way of doing quantum metrology.

    “Scientists often say that ‘there is no such thing as a free lunch’, meaning that you cannot gain anything if you are unwilling to pay the computational price,” said co-author Aleksander Lasek, a PhD candidate at the Cavendish Laboratory. “However, in quantum metrology this price can be made arbitrarily low. That’s highly counterintuitive, and truly amazing!”

    Dr Nicole Yunger Halpern, co-author and ITAMP Postdoctoral Fellow at Harvard University, said: “Everyday multiplication commutes: Six times seven equals seven times six. Quantum theory involves multiplication that doesn’t commute. The lack of commutation lets us improve metrology using quantum physics.

    “Quantum physics enhances metrology, computation, cryptography, and more; but proving rigorously that it does is difficult. We showed that quantum physics enables us to extract more information from experiments than we could with only classical physics. The key to the proof is a quantum version of probabilities — mathematical objects that resemble probabilities but can assume negative and non-real values.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 5:24 pm on January 23, 2020 Permalink | Reply
    Tags: "Large Amounts of Oxygen Detected in Ancient Star’s Atmosphere", , , , , Halo stars-roughly spherical distribution around the Milky Way, , Old star J0815+4729, , University of Cambridge   

    From UC San Diego: “Large Amounts of Oxygen Detected in Ancient Star’s Atmosphere” 

    From UC San Diego

    Cynthia Dillon, 858-822-0142, cdillon@ucsd.edu


    This animation illustrates the earliest epoch of our universe, just after the Big Bang, when the first elements of hydrogen, helium and lithium were created in the still hot cosmos. These atoms eventually collected to form the first generation of massive stars, which in turn produced heavier elements such as carbon, oxygen and nitrogen. As these massive stars exploded as supernovae, they released these heavier elements into the universe, eventually collecting on next generation stars such as J0815+4729. Video courtesy of Gabriel Pérez, SMM (IAC); IACVideos, YouTube

    An international team of astronomers from the University of California San Diego, the Instituto de Astrofísica de Canarias (IAC) and the University of Cambridge have detected large amounts of oxygen in the atmosphere of one of the oldest and most elementally depleted stars known—a primitive star scientists call “J0815+4729.” This new finding, reported in The Astrophysical Journal Letters, provides an important clue about how oxygen and other important elements were produced in the universe’s first generations of stars.

    1
    Artistic image of the supernova explosions of the first massive stars that formed in the Milky Way. The star J0815+4729 was formed from the material ejected by these first supernovae. Image courtesy of Gabriel Pérez, SMM (IAC).

    After hydrogen and helium, oxygen is the third most abundant element in the universe and important to all life forms on Earth. It serves as a chemical basis of respiration and a building block of carbohydrates, as well as the main element in the Earth’s crust. Absent from the early universe, it emerged through nuclear fusion reactions that occurred deep inside the most massive stars—stars roughly 10 times or more massive than the sun.

    To trace this early production of oxygen and other elements, astronomers study the oldest existing stars. J0815+4729 is one of them. It was first discovered by the IAC team in 2017 using the Grand Canary Telescope in La Palma, in the Canaries, Spain.

    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    It resides over 5,000 light years away toward the constellation Lynx.

    “Stars like J0815+4729 are referred to as halo stars,” explained UC San Diego Professor of Physics Adam Burgasser, a co-author of the study. “This is due to their roughly spherical distribution around the Milky Way, as opposed to the more familiar flat disk of younger stars that include the sun.”

    Halo stars like J0815+4729 are truly ancient stars, allowing astronomers a peek into the universe’s early history of element production. The research team observed J0815+4729 with the W. M. Keck Observatory’s Keck I 10-meter telescope on Mauna Kea, Hawaii, using a high resolution spectrograph called HIRES.

    Keck Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope, Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft) above sea level

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

    The data, which required more than five hours of staring at the star over a single night, were used to measure the abundances of 16 chemical species in the star’s atmosphere, including oxygen.

    “The primitive composition of the star indicates that it was formed during the first hundreds of millions of years after the Big Bang, possibly from the material expelled from the first supernovae of the Milky Way,” said Jonay González Hernández, an IAC Ramón y Cajal postdoctoral researcher and lead author of the study.

    The chemical composition of the star was found to be very unusual. While it has relatively large amounts of carbon, nitrogen and oxygen, approximately 10, 8 and 3 percent of the abundances measured in the sun, other elements like calcium and iron have abundances around one millionth that of the sun.

    “Only a few such stars are known in the halo of our galaxy, but none have such an enormous amount of carbon, nitrogen and oxygen compared to their iron content,” said David Aguado, a postdoctoral researcher at the University of Cambridge and co-author of the study.

    The search for stars of this type involves dedicated projects that sift through hundreds of thousands of stellar spectra to uncover a few rare sources like J0815+4729 and follow-up observation to measure their chemical composition. This star was first discovered in data obtained with the Sloan Digital Sky Survey (SDSS).

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude2,788 meters (9,147 ft)

    According to Rafael Rebolo, IAC director and co-author of the paper, the institute began studying the presence of oxygen in the oldest stars of the galaxy 30 years ago, with results indicating that this element was produced enormously in the first generations of supernovae.

    “However, we could not imagine that we would find a case of enrichment as spectacular as that of this star,” Rebolo noted.

    The researchers acknowledge Heather Hershley and Sherry Yeh at Keck Observatory for their assistance with the observations; financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) under the 2013 Ramón y Cajal program (RYC-2013-14875); the Spanish Ministry project MICIU (AYA2017-86389-P) and Leverhulme Trust.

    UC San Diego’s Department of Physics in the Division of Physical Sciences offers one of the top graduate programs in the U.S. Many of its faculty are active at the Center for Astrophysics and Space Sciences (CASS), an interdisciplinary research unit for research and graduate study in astronomy, astrophysics and space sciences. Areas of specialization include high-energy astrophysics, optical and ultraviolet astronomy, infrared astronomy, radio astronomy, theoretical astrophysics, cosmology, solar physics, space plasma physics, interferometry and astronomical instrumentation.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of California, San Diego (also referred to as UC San Diego or UCSD), is a public research university located in the La Jolla area of San Diego, California, in the United States.[12] The university occupies 2,141 acres (866 ha) near the coast of the Pacific Ocean with the main campus resting on approximately 1,152 acres (466 ha).[13] Established in 1960 near the pre-existing Scripps Institution of Oceanography, UC San Diego is the seventh oldest of the 10 University of California campuses and offers over 200 undergraduate and graduate degree programs, enrolling about 22,700 undergraduate and 6,300 graduate students. UC San Diego is one of America’s Public Ivy universities, which recognizes top public research universities in the United States. UC San Diego was ranked 8th among public universities and 37th among all universities in the United States, and rated the 18th Top World University by U.S. News & World Report ‘s 2015 rankings.

     
  • richardmitnick 10:13 am on December 7, 2019 Permalink | Reply
    Tags: "Drone images show Greenland Ice Sheet becoming more unstable as it fractures", , , , University of Cambridge   

    From University of Cambridge: “Drone images show Greenland Ice Sheet becoming more unstable as it fractures” 

    U Cambridge bloc

    From University of Cambridge

    12.7.19
    Sarah Collins

    1
    phys.org

    The world’s second-largest ice sheet, and the single largest contributor to global sea level rise, is potentially becoming unstable because of fractures developing in response to faster ice flow and more meltwater forming on its surface.

    Using custom-built drones strong enough to withstand the extreme Arctic conditions, researchers led by the University of Cambridge made the first drone-based observations of how fractures form under meltwater lakes on the Greenland Ice Sheet. These fractures cause catastrophic lake drainages, in which huge quantities of surface water are transferred to the sensitive environment beneath the ice.

    The study, published in the Proceedings of the National Academy of Sciences, shows how the water is transferred and how the ice sheet responds. The researchers found that inflowing meltwater expanded the lake and drainage began when the edge of the lake intersected a fracture, which formed one year earlier.

    2
    U Cambridge

    Each summer, thousands of lakes form on the Greenland Ice Sheet as the weather warms. Many of these lakes can drain in just a few hours, creating caverns known as moulins, through which water descends to the bottom of the ice sheet.

    These cavities typically stay open for the remainder of the melt season, as meltwater from streams and rivers on the surface descends beneath the ice. Given that the ice sheet is typically a kilometre thick or more, the flow of water into the moulins may well be the world’s largest waterfalls.

    While conducting the research from a camp on Store Glacier in northwest Greenland, the team witnessed how this fracture became active and how it propagated 500 metres further into the lake, causing the lake to drain rapidly. In multiple drone flights, the team was able to document the flow of water into the fracture and the water’s subsequent pathway under the ice.

    3
    After draining, lakes leave behind holes called ‘moulins’, which allow meltwater to continue to travel to the bottom of the ice sheet.

    In a detailed reconstruction of the event, which is rarely observed directly, the team, which also included researchers from Aberystwyth and Lancaster Universities, showed how the meltwater causes the formation of new fractures, as well as the expansion of dormant fractures.

    In just five hours, five million cubic metres of water – the equivalent of 2,000 Olympic-sized swimming pools – drained to the bottom of the ice sheet via the fracture, causing a new cavity to form and reducing the lake to a third of its original volume. This caused the ice flow to accelerate from a speed of two metres per day to more than five metres per day as surface water was transferred to the bed, which in turn lifted the ice sheet by half a metre.

    The drone footage supports computer models used by the same team of researchers to show that drainage of melt lakes in Greenland can occur in a chain reaction. The new study provides an insight as to how these chain reactions might be triggered, via lakes that can drain through existing fractures.

    “It’s possible we’ve under-estimated the effects of these glaciers on the overall instability of the Greenland Ice Sheet,” said first author Tom Chudley, a PhD student at the Scott Polar Research Institute and the team’s drone pilot. “It’s a rare thing to actually observe these fast-draining lakes – we were lucky to be in the right place at the right time.”

    “These glaciers are already moving quite fast, so the effect of the lakes may not appear to be as dramatic as it is on slower-moving glaciers elsewhere, but the overall effect is in fact very significant,” said Dr Poul Christoffersen, who led the expedition. “To date, most observations are provided by satellites. These allow us to see what’s happening over the whole ice sheet, but drone-based observations give a lot more nuance to our understanding of these lake drainages. We can also observe the formation and re-opening of fractures, which isn’t possible from satellites.”

    The drones, which were built at the Scott Polar Research Institute, were fitted with autopilot and navigated autonomously along pre-programmed flight paths in missions that lasted up to an hour each. By also fitting on-board GPS, the team was able to accurately geo-locate and stitch together hundreds of photos taken during each survey. The photos were used to create detailed 3D reconstructions of the ice sheet surface.

    The findings show that fast-flowing glaciers in Greenland are subject to significant forcing by surface meltwater. They also show that changes in ice flow occur on much shorter timescales than considered possible so far.

    Christoffersen leads the EU-funded RESPONDER project, of which this study was a part. The RESPONDER team are using the drone footage to identify ‘hotspots’ where the ice sheet behaves sensitively.

    Using drilling equipment, the team is now exploring how the water is accommodated in the basal drainage system and how the ice sheet may change over the coming decades as the climate continues to warm.

    The difference between snow accumulation and loss of ice in Greenland ice sheet currently amounts to one billion tonnes of ice being lost every day. This net loss of ice is growing, making the Greenland Ice Sheet the single largest contributor to global sea level rise.

    The RESPONDER project is funded by the European Research Council under the European Union’s Horizon 2020 programme. Chudley is supported by the Natural Environment Research Council.

    3
    Researchers flew drones over the lake as it was draining, building 3D models of the ice sheet surface as well as capturing spectacular images of waterfalls entering the depths of the ice sheet. Credit: Tom Chudley

    4
    https://smartwatermagazine.com

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 9:10 am on October 26, 2019 Permalink | Reply
    Tags: "‘Artificial leaf’ successfully produces clean gas ", , , , , , , University of Cambridge   

    From University of Cambridge: “‘Artificial leaf’ successfully produces clean gas “ 

    U Cambridge bloc

    From University of Cambridge

    21 Oct 2019
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    Artificial leaf. Credit: Virgil Andrei

    A widely-used gas that is currently produced from fossil fuels can instead be made by an ‘artificial leaf’ that uses only sunlight, carbon dioxide and water, and which could eventually be used to develop a sustainable liquid fuel alternative to petrol.

    The carbon-neutral device sets a new benchmark in the field of solar fuels, after researchers at the University of Cambridge demonstrated that it can directly produce the gas – called syngas – in a sustainable and simple way.

    Rather than running on fossil fuels, the artificial leaf is powered by sunlight, although it still works efficiently on cloudy and overcast days. And unlike the current industrial processes for producing syngas, the leaf does not release any additional carbon dioxide into the atmosphere. The results are reported in the journal Nature Materials.

    Syngas is currently made from a mixture of hydrogen and carbon monoxide, and is used to produce a range of commodities, such as fuels, pharmaceuticals, plastics and fertilisers.

    “You may not have heard of syngas itself but every day, you consume products that were created using it. Being able to produce it sustainably would be a critical step in closing the global carbon cycle and establishing a sustainable chemical and fuel industry,” said senior author Professor Erwin Reisner from Cambridge’s Department of Chemistry, who has spent seven years working towards this goal.

    The device Reisner and his colleagues produced is inspired by photosynthesis – the natural process by which plants use the energy from sunlight to turn carbon dioxide into food.

    On the artificial leaf, two light absorbers, similar to the molecules in plants that harvest sunlight, are combined with a catalyst made from the naturally abundant element cobalt.

    When the device is immersed in water, one light absorber uses the catalyst to produce oxygen. The other carries out the chemical reaction that reduces carbon dioxide and water into carbon monoxide and hydrogen, forming the syngas mixture.

    As an added bonus, the researchers discovered that their light absorbers work even under the low levels of sunlight on a rainy or overcast day.

    “This means you are not limited to using this technology just in warm countries, or only operating the process during the summer months,” said PhD student Virgil Andrei, first author of the paper. “You could use it from dawn until dusk, anywhere in the world.”

    The research was carried out in the Christian Doppler Laboratory for Sustainable SynGas Chemistry in the University’s Department of Chemistry. It was co-funded by the Austrian government and the Austrian petrochemical company OMV, which is looking for ways to make its business more sustainable.

    “OMV has been an avid supporter of the Christian Doppler Laboratory for the past seven years. The team’s fundamental research to produce syngas as the basis for liquid fuel in a carbon neutral way is ground-breaking,” said Michael-Dieter Ulbrich, Senior Advisor at OMV.

    Other ‘artificial leaf’ devices have also been developed, but these usually only produce hydrogen. The Cambridge researchers say the reason they have been able to make theirs produce syngas sustainably is thanks the combination of materials and catalysts they used.

    These include state-of-the-art perovskite light absorbers, which provide a high photovoltage and electrical current to power the chemical reaction by which carbon dioxide is reduced to carbon monoxide, in comparison to light absorbers made from silicon or dye-sensitised materials. The researchers also used cobalt as their molecular catalyst, instead of platinum or silver. Cobalt is not only lower-cost, but it is better at producing carbon monoxide than other catalysts.

    The team is now looking at ways to use their technology to produce a sustainable liquid fuel alternative to petrol.

    Syngas is already used as a building block in the production of liquid fuels. “What we’d like to do next, instead of first making syngas and then converting it into liquid fuel, is to make the liquid fuel in one step from carbon dioxide and water,” said Reisner, who is also a Fellow of St John’s College.

    Although great advances are being made in generating electricity from renewable energy sources such as wind power and photovoltaics, Reisner says the development of synthetic petrol is vital, as electricity can currently only satisfy about 25% of our total global energy demand. “There is a major demand for liquid fuels to power heavy transport, shipping and aviation sustainably,” he said.

    “We are aiming at sustainably creating products such as ethanol, which can readily be used as a fuel,” said Andrei. “It’s challenging to produce it in one step from sunlight using the carbon dioxide reduction reaction. But we are confident that we are going in the right direction, and that we have the right catalysts, so we believe we will be able to produce a device that can demonstrate this process in the near future.”

    The research was also funded by the Winton Programme for the Physics of Sustainability, the Biotechnology and Biological Sciences Research Council, and the Engineering and Physical Sciences Research Council.

    See the full article here .

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    Please help promote STEM in your local schools.

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    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 8:51 am on August 12, 2019 Permalink | Reply
    Tags: "Crystal Clocks Serve as Stopwatch for Magma Storage and Travel Times", , , , , The mineral’s composition changes creating a kind of crystal clock., The team used a volcanic mineral called spinel as a crystal stopwatch., University of Cambridge,   

    From U Cambridge via Eos: “Crystal Clocks Serve as Stopwatch for Magma Storage and Travel Times” 

    U Cambridge bloc

    From University of Cambridge

    Via

    AGU
    Eos news bloc

    Eos

    8.12.19
    Mary Caperton Morton

    Magma stored for 1,000 years in an Icelandic volcano journeyed to the surface in just 4 days.

    1
    The 2014–2015 eruption of Iceland’s Holuhraun lava field had an eruption style similar to the Borgarhraun eruption of Iceland’s Theistareykir volcano, which took place 10,000 years ago. Credit: Euan J. F. Mutch

    Volcanic eruptions are just the tip of the iceberg: Hidden deep below ground, the preeruption behavior and movements of magma remain largely mysterious. Two new studies centered around a volcano in Iceland are shedding light on how long magma was stored deep underground and how long it took to travel to the surface before erupting, information that may be used to improve existing models of complex magmatic systems.

    Geophysical monitoring methods can see only so deep beneath the surface of Earth, so to figure out what is happening deep inside a volcano, “you have to be a geological detective,” said Euan Mutch, an igneous petrologist at the University of Cambridge in the United Kingdom and lead author on both of the new studies, published in Science and Nature Geoscience.

    Mutch and colleagues at the University of Cambridge focused on the Borgarhraun eruption of Theistareykir, a volcano in northern Iceland, which took place around 10,000 years ago. Previous studies have shown the magma that fed this eruption came directly from the Mohorovičić discontinuity (the Moho), where Earth’s crust meets its mantle, at a depth of about 24 kilometers—far deeper than geophysical methods can see clearly.

    To determine how long the magma was stored at the Moho before erupting, the team used a volcanic mineral called spinel as a crystal stopwatch.

    “The elements in the crystal want to be in equilibrium with the surroundings,” Mutch explained.

    As the elements equilibrate by diffusing out of the spinel, the mineral’s composition changes, creating a kind of crystal clock. Using known diffusion rates for aluminum and chromium, the team was able to determine how long the minerals were stored in the melt before it erupted, in this case about a thousand years, they wrote in Science.

    2
    Mineral maps like this one show areas of concentrated aluminum in yellow and lower concentrations in red and black. The process of diffusion from high to low concentration can be used to estimate how long the crystal remained in the magma chamber before erupting. Credit: Euan J. F. Mutch

    In the Nature Geoscience study, Mutch and colleagues used a similar diffusion modeling technique on olivine crystals to show that the magma ascended from the Moho to the surface in as little as 4 days, at a rate of 0.02 to 0.1 meter per second.

    The two studies represent some of the first evidence of magmatic timescales for eruptions originating in the deep crust at the Moho boundary, said David Neave, a petrologist at the University of Manchester in the United Kingdom who was not involved in either of the new studies.

    “A lot of progress has been made understanding timescales of shallower volcanoes, but these are the first studies to estimate how long magma is stored in the deep crust before it erupts,” Neave said. “That’s crucial new information.”

    Diffusion modeling is not a new technique. The methods have been around for at least 10 years, Neave said, but Mutch and colleagues “were very clever in working out the uncertainties and arrived at much more precise estimates for these timescales than previous groups have been able to do.”

    The findings also lend support to a growing body of research suggesting that magmatic systems can be much more complex than the textbook model of a volcano fed directly from a single bulbous magma chamber, said Stephen Sparks, a volcanologist at the University of Bristol in the United Kingdom who was not involved in either of the new studies.

    “Their results contribute to the evidence that supports vertically extensive transcrustal magma systems,” Sparks said. The study does not introduce any fundamentally new concepts but “supports this emerging new paradigm. The paper is amongst the most thorough and convincing published so far.”

    Applying the Techniques to Other Volcanoes

    Whether the 1,000-year timescales for magma storage and mere days of travel to the surface are typical of other volcanoes or unique to Theistareykir is unknown, Mutch said. The next steps will be to apply the same diffusion modeling techniques to other eruptions.

    Crystal clocks can be used at a variety of volcano types, not just the basaltic volcanoes found in Iceland, Neave said.

    “Most volcanoes are ultimately underlain by basaltic materials, even if they’re erupting rhyolite or andesite at the surface like at the Cascades volcanoes [in the United States],” he said. “I think this approach will prove to be widely applicable to a range of volcanic settings.”

    The findings may ultimately aid in developing more accurate magmatic and eruption models as well as improving volcanic hazard forecasts, Mutch said. The Nature Geoscience paper in particular showed a link between the magma’s rate of ascent and the release of carbon dioxide, which could be used to predict an impending eruption.

    “At the ascent rates estimated for the Borgarhraun magma, an increase in carbon dioxide flux at the surface would only be detected at most 2 days before the eruption,” Mutch said. However, other volcanic systems may offer more lead time: “This threshold will be different for magmas with different carbon contents and that are stored at different depths before eruption.”

    See the full article here .

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    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 2:26 pm on May 9, 2019 Permalink | Reply
    Tags: , University of Cambridge   

    From University of Cambridge: “Design work on ‘brain’ of world’s largest radio telescope completed” 

    U Cambridge bloc

    From University of Cambridge

    09 May 2019
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    Artist’s impression of the full Square Kilometre Array at night

    An international group of scientists led by the University of Cambridge has finished designing the ‘brain’ of the Square Kilometre Array (SKA), the world’s largest radio telescope. When complete, the SKA will enable astronomers to monitor the sky in unprecedented detail and survey the entire sky much faster than any system currently in existence.

    The SKA’s Science Data Processor (SDP) consortium has concluded its engineering design work, marking the end of five years’ work to design one of two supercomputers that will process the enormous amounts of data produced by the SKA’s telescopes.

    The SDP consortium, led by the University of Cambridge, has designed the elements that will together form the ‘brain’ of the SKA. SDP is the second stage of processing for the masses of digitised astronomical signals collected by the telescope’s receivers. In total, close to 40 institutions in 11 countries took part.

    The UK government, through the Science and Technology Facilities Council (STFC), has committed £100m to the construction of the SKA and the SKA Headquarters, as its share as a core member of the project. The global headquarters of the SKA Organisation are located in the UK at Jodrell Bank, home to the iconic Lovell Telescope

    “It’s been a real pleasure to work with such an international team of experts, from radio astronomy but also the High-Performance Computing industry,” said Maurizio Miccolis, SDP’s Project Manager for the SKA Organisation. “We’ve worked with almost every SKA country to make this happen, which goes to show how hard what we’re trying to do is.”

    The role of the consortium was to design the computing hardware platforms, software, and algorithms needed to process science data from the Central Signal Processor (CSP) into science data products.

    “SDP is where data becomes information,” said Rosie Bolton, Data Centre Scientist for the SKA Organisation. “This is where we start making sense of the data and produce detailed astronomical images of the sky.”

    To do this, SDP will need to ingest the data and move it through data reduction pipelines at staggering speeds, to then form data packages that will be copied and distributed to a global network of regional centres where it will be accessed by scientists around the world.

    SDP itself will be composed of two supercomputers, one located in Cape Town, South Africa and one in Perth, Australia.

    “We estimate SDP’s total compute power to be around 250 PFlops – that’s 25% faster than IBM’s Summit, the current fastest supercomputer in the world,” said Maurizio. “In total, up to 600 petabytes of data will be distributed around the world every year from SDP –enough to fill more than a million average laptops.”

    Additionally, because of the sheer quantity of data flowing into SDP: some 5 Tb/s, or 100,000 times faster than the projected global average broadband speed in 2022, it will need to make decisions on its own in almost real-time about what is noise and what is worthwhile data to keep.

    The team also designed SDP so that it can detect and remove manmade radio frequency interference (RFI) – for example from satellites and other sources – from the data.

    “By pushing what’s technologically feasible and developing new software and architecture for our HPC needs, we also create opportunities to develop applications in other fields,” said Maurizio.

    High-Performance Computing plays an increasingly vital role in enabling research in fields such as weather forecasting, climate research, drug development and many others where cutting-edge modelling and simulations are essential.

    Professor Paul Alexander, Consortium Lead from Cambridge’s Cavendish Laboratory said: “I’d like to thank everyone involved in the consortium for their hard work over the years. Designing this supercomputer wouldn’t have been possible without such an international collaboration behind it.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 10:22 am on February 23, 2019 Permalink | Reply
    Tags: , , , , , , , University of Cambridge   

    From University of Cambridge: “Physicists get thousands of semiconductor nuclei to do ‘quantum dances’ in unison” 

    U Cambridge bloc

    From University of Cambridge

    22 Feb 2019
    Communications office

    1
    Theoretical ESR spectrum buildup as a function of two-photon detuning δ and drive time τ, for a Rabi frequency of Ω = 3.3 MHz on the central transition. Credit: University of Cambridge.

    A team of Cambridge researchers have found a way to control the sea of nuclei in semiconductor quantum dots so they can operate as a quantum memory device.

    Quantum dots are crystals made up of thousands of atoms, and each of these atoms interacts magnetically with the trapped electron. If left alone to its own devices, this interaction of the electron with the nuclear spins, limits the usefulness of the electron as a quantum bit – a qubit.

    Led by Professor Mete Atatüre from Cambridge’s Cavendish Laboratory, the researchers are exploiting the laws of quantum physics and optics to investigate computing, sensing or communication applications.

    “Quantum dots offer an ideal interface, as mediated by light, to a system where the dynamics of individual interacting spins could be controlled and exploited,” said Atatüre, who is a Fellow of St John’s College. “Because the nuclei randomly ‘steal’ information from the electron they have traditionally been an annoyance, but we have shown we can harness them as a resource.”

    The Cambridge team found a way to exploit the interaction between the electron and the thousands of nuclei using lasers to ‘cool’ the nuclei to less than 1 milliKelvin, or a thousandth of a degree above the absolute zero temperature. They then showed they can control and manipulate the thousands of nuclei as if they form a single body in unison, like a second qubit. This proves the nuclei in the quantum dot can exchange information with the electron qubit and can be used to store quantum information as a memory device. The results are reported in the journal Science.

    Quantum computing aims to harness fundamental concepts of quantum physics, such as entanglement and superposition principle, to outperform current approaches to computing and could revolutionise technology, business and research. Just like classical computers, quantum computers need a processor, memory, and a bus to transport the information backwards and forwards. The processor is a qubit which can be an electron trapped in a quantum dot, the bus is a single photon that these quantum dots generate and are ideal for exchanging information. But the missing link for quantum dots is quantum memory.

    Atatüre said: “Instead of talking to individual nuclear spins, we worked on accessing collective spin waves by lasers. This is like a stadium where you don’t need to worry about who raises their hands in the Mexican wave going round, as long as there is one collective wave because they all dance in unison.

    “We then went on to show that these spin waves have quantum coherence. This was the missing piece of the jigsaw and we now have everything needed to build a dedicated quantum memory for every qubit.”

    In quantum technologies, the photon, the qubit and the memory need to interact with each other in a controlled way. This is mostly realised by interfacing different physical systems to form a single hybrid unit which can be inefficient. The researchers have been able to show that in quantum dots, the memory element is automatically there with every single qubit.

    Dr Dorian Gangloff, one of the first authors of the paper [Science] and a Fellow at St John’s, said the discovery will renew interest in these types of semiconductor quantum dots. Dr Gangloff explained: “This is a Holy Grail breakthrough for quantum dot research – both for quantum memory and fundamental research; we now have the tools to study dynamics of complex systems in the spirit of quantum simulation.”

    The long term opportunities of this work could be seen in the field of quantum computing. Last month, IBM launched the world’s first commercial quantum computer, and the Chief Executive of Microsoft has said quantum computing has the potential to ‘radically reshape the world’.

    Gangloff said: “The impact of the qubit could be half a century away but the power of disruptive technology is that it is hard to conceive of the problems we might open up – you can try to think of it as known unknowns but at some point you get into new territory. We don’t yet know the kind of problems it will help to solve which is very exciting.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
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