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  • richardmitnick 1:23 pm on May 13, 2017 Permalink | Reply
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    From Cambridge via phys.org: “Scientists investigate debris disk in a nearby planetary system” 

    U Cambridge bloc

    Cambridge University

    phys.org

    May 11, 2017
    Tomasz Nowakowski

    2
    ALMA band 7 (0.86 mm) continuum image of 61 Vir with natural weights and corrected by the primary beam response (FWHM∼ 1700). Credit: Marino et al., 2017.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    Astronomers have recently presented new results of observations of a nearby planetary system known as 61 Virginis (or 61 Vir for short). The observations were focused on investigating the system’s debris disk, which could hold many clues to the nature of planetary formation beyond our solar system. The study is available in a paper published May 4, 2017.

    61 Vir is a G-type, 4.6-billion-year-old main-sequence star about the size of our sun, located approximately 28 light years away. The star is known to be orbited by at least three planets that are five, 18 and 23 times more massive than Earth. One of the most intriguing features of this system is a debris disk extending from 30 to at least 100 AU from the star.

    Debris disks are clouds of planetesimals and dust found in orbits around many stars. Studying such disks could improve our understanding about planet formation and the migration history of planets in planetary systems. With this aim in mind, a team of astronomers led by Sebastian Marino of the University of Cambridge in the U.K., has performed observations of 61 Vir’s debris disk using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. These observations were complemented by data from the Submillimetre Common-User Bolometer Array 2 (SCUBA2) installed in the James Clerk Maxwell Telescope (JCMT) at Mauna Kea Observatory in Hawaii.

    East Asia Observatory James Clerk Maxwell telescope, Mauna Kea, Hawaii, USA

    “In this paper, we present the first observations of 61 Vir with ALMA at 0.86 mm, obtained with the aim of studying its debris disc to reveal the location of the parent planetesimals, and place constraints on the presence of planets at large separations that can shape the mass distribution in the disc. (…) In order to obtain the best disc constraints, in our analysis we combine new ALMA band 7 observations and new data at 0.85 mm from SCUBA2 installed on JCMT, thus, incorporating information from small and large angular scale structure,” the researchers wrote in the paper.

    The new study reveals that the debris disk is larger than previously thought. Marino’s team found that it extends from 30 to at least 150 AU. Combined ALMA and SCUBA2/JMCT observations also show that at 0.86 mm the total disc emission is about 3.7 mJy and the disk has a surface density distribution of millimeter sized grains with a power law slope of approximately 0.1.

    Moreover, the researchers assume that a yet unseen fourth planet may lurk somewhere in the system between 61 Vir d at 0.5 AU and the inner edge of the disc. They argue that if the disc was stirred at 150 AU by an additional planet, that unseen alien world should have a mass of at least 10 Earth masses and should orbit its host at a distance between 10 and 20 AU.

    “We found that in order to have stirred the disc out to 150 AU, the planet must be more massive than 10 Earth masses and a semi-major axis between 10 and 20 AU if it has an eccentricity lower than 0.1. Otherwise, for higher eccentricities, it could have a lower mass and a semi-major axis between 4 and 20 AU,” the team concluded.

    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 10:58 am on September 7, 2016 Permalink | Reply
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    From U Cambridge: “Massive holes ‘punched’ through a trail of stars likely caused by dark matter” 

    U Cambridge bloc

    Cambridge University

    07 Sep 2016
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    Artist’s impression of dark matter clumps around a Milky Way-like galaxy. Credit: V. Belokurov, D. Erkal, S.E. Koposov (IoA, Cambridge). Photo: Colour image of M31 from Adam Evans.

    The discovery of two massive holes punched through a stream of stars could help answer questions about the nature of dark matter, the mysterious substance holding galaxies together.

    Researchers have detected two massive holes which have been ‘punched’ through a stream of stars just outside the Milky Way, and found that they were likely caused by clumps of dark matter, the invisible substance which holds galaxies together and makes up a quarter of all matter and energy in the universe.

    The scientists, from the University of Cambridge, found the holes by studying the distribution of stars in the Milky Way. While the clumps of dark matter that likely made the holes are gigantic in comparison to our Solar System – with a mass between one million and 100 million times that of the Sun – they are actually the tiniest clumps of dark matter detected to date.

    The results, which have been submitted to the Monthly Notices of the Royal Astronomical Society, could help researchers understand the properties of dark matter, by inferring what type of particle this mysterious substance could be made of. According to their calculations and simulations, dark matter is likely made up of particles more massive and more sluggish than previously thought, although such a particle has yet to be discovered.

    “While we do not yet understand what dark matter is formed of, we know that it is everywhere,” said Dr Denis Erkal from Cambridge’s Institute of Astronomy, the paper’s lead author. “It permeates the universe and acts as scaffolding around which astrophysical objects made of ordinary matter – such as galaxies – are assembled.”

    Current theory on how the universe was formed predicts that many of these dark matter building blocks have been left unused, and there are possibly tens of thousands of small clumps of dark matter swarming in and around the Milky Way. These small clumps, known as dark matter sub-haloes, are completely dark, and don’t contain any stars, gas or dust.

    Dark matter cannot be directly measured, and so its existence is usually inferred by the gravitational pull it exerts on other objects, such as by observing the movement of stars in a galaxy. But since sub-haloes don’t contain any ordinary matter, researchers need to develop alternative techniques in order to observe them.

    The technique the Cambridge researchers developed was to essentially look for giant holes punched through a stream of stars. These streams are the remnants of small satellites, either dwarf galaxies or globular clusters, which were once in orbit around our own galaxy, but the strong tidal forces of the Milky Way have torn them apart. The remnants of these former satellites are often stretched out into long and narrow tails of stars, known as stellar streams.

    “Stellar streams are actually simple and fragile structures,” said co-author Dr Sergey Koposov. “The stars in a stellar stream closely follow one another since their orbits all started from the same place. But they don’t actually feel each other’s presence, and so the apparent coherence of the stream can be fractured if a massive body passes nearby. If a dark matter sub-halo passes through a stellar stream, the result will be a gap in the stream which is proportional to the mass of the body that created it.”

    The researchers used data from the stellar streams in the Palomar 5 globular cluster to look for evidence of a sub-halo fly-by. Using a new modelling technique, they were able to observe the stream with greater precision than ever before. What they found was a pair of wrinkled tidal tails, with two gaps of different widths.

    By running thousands of computer simulations, the researchers determined that the gaps were consistent with a fly-by of a dark matter sub-halo. If confirmed, these would be the smallest dark matter clumps detected to date.

    “If dark matter can exist in clumps smaller than the smallest dwarf galaxy, then it also tells us something about the nature of the particles which dark matter is made of – namely that it must be made of very massive particles,” said co-author Dr Vasily Belokurov. “This would be a breakthrough in our understanding of dark matter.”

    The reason that researchers can make this connection is that the mass of the smallest clump of dark matter is closely linked to the mass of the yet unknown particle that dark matter is composed of. More precisely, the smaller the clumps of dark matter, the higher the mass of the particle.

    Since we do not yet know what dark matter is made of, the simplest way to characterise the particles is to assign them a particular energy or mass. If the particles are very light, then they can move and disperse into very large clumps. But if the particles are very massive, then they can’t move very fast, causing them to condense – in the first instance – into very small clumps.

    “Mass is related to how fast these particles can move, and how fast they can move tells you about their size,” said Belokurov. “So that’s why it’s so interesting to detect very small clumps of dark matter, because it tells you that the dark matter particle itself must be very massive.”

    “If our technique works as predicted, in the near future we will be able to use it to discover even smaller clumps of dark matter,” said Erkal. “It’s like putting dark matter goggles on and seeing thousands of dark clumps each more massive than a million suns whizzing around.”

    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 9:34 am on September 5, 2016 Permalink | Reply
    Tags: , , U Cambridge   

    From U Cambridge: “New exoplanet think tank will ask the big questions about extra-terrestrial worlds” 

    U Cambridge bloc

    Cambridge University

    05 Sep 2016
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    Artist’s impression of the ultracool dwarf star TRAPPIST-1 from the surface of one of its planets Credit: ESO/M. Kornmesser

    ESO Trappist InteriorESO Trappist National Telescope at La Silla
    ESO Belgian Trappist National Telescope at Cerro La Silla, Chile

    An international exoplanet ‘think tank’ is meeting this week in Cambridge to deliberate on the ten most important questions that humanity could answer in the next decade about planets outside our solar system.

    With funding from The Kavli Foundation, the think tank will bring together some of the major researchers in exoplanetary science – arguably the most exciting field in modern astronomy – for a series of annual meetings to address the biggest questions in this field which humanity could conceivably answer in the next decade.

    “We’re really at the frontier in exoplanet research,” said Dr Nikku Madhusudhan of Cambridge’s Institute of Astronomy, who is leading the think tank. “The pace of new discoveries is incredible – it really feels like anything can be discovered any moment in our exploration of extra-terrestrial worlds. By bringing together some of the best minds in this field we aim to consolidate our collective wisdom and address the biggest questions in this field that humanity can ask and answer at this time.”

    Tremendous advances have been made in the study of exoplanets since the first such planet was discovered around a sun-like star in 1995 by the Cavendish Laboratory’s Professor Didier Queloz. Just last month, a potentially habitable world was discovered in our own neighbourhood, orbiting Proxima Centauri, the nearest star to the sun.

    Pale Red Dot
    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker
    ESO/Pale Red Dot; Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    However, there are still plenty questions to be answered, such as whether we’re capable of detecting signatures of life on other planets within the next ten years, what the best strategies are to find habitable planets, how diverse are planets and their atmospheres, and how planets form in the first place.

    With at least four space missions and numerous large ground-based facilities scheduled to become operational in the next decade, exoplanetary scientists will be able to detect more and more exoplanets, and will also have the ability to conduct detailed studies of their atmospheres, interiors, and formation conditions. At the same time, major developments are expected in all aspects of exoplanetary theory and data interpretation.

    In order to make these major advances in the field, new interdisciplinary approaches are required. Additionally, as new scientific questions and areas emerge at an increasingly fast pace, there is a need for a focused forum where emerging questions in frontier areas of the field can be discussed. “Given the exciting advancements in exoplanetary science now is the right time to assess the state of the field and the scientific challenges and opportunities on the horizon,” said Professor Andy Fabian, director of the Institute of Astronomy at Cambridge.

    The think tank will operate in the form of a yearly Exoplanet Symposium series which will be focused on addressing pressing questions in exoplanetary science. One emerging area or theme in exoplanetary science will be chosen each year based on its critical importance to the advancement of the field, relevance to existing or imminent observational facilities, need for an interdisciplinary approach, and/or scope for fundamental breakthroughs.

    About 30 experts in the field from around the world will discuss outstanding questions, new pathways, interdisciplinary synergies, and strategic actions that could benefit the exoplanet research community.

    The inaugural symposium, “Kavli ExoFrontiers 2016”, is being held this week in Cambridge. The goal of this first symposium is to bring together experts from different areas of exoplanetary science to share their visions about the most pressing questions and future outlook of their respective areas. These visions will help provide both a broad outlook of the field and identify the ten most important questions in the field that could be addressed within the next decade. “We hope the think tank will provide a platform for new breakthroughs in the field through interdisciplinary and international efforts while bringing the most important scientific questions of our time to the fore,” said Madhusudhan. “We are in the golden age of exoplanetary science.”

    More information about the Kavli ExoFrontiers 2016 Symposium is available at: http://www.ast.cam.ac.uk/meetings/2016/kavli.exofrontiers.2016.symposium

    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 6:49 am on August 30, 2016 Permalink | Reply
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    From U Cambridge: “Tiny changes in Parkinson’s protein can have “dramatic” impact on processes that lead to the disease” 

    U Cambridge bloc

    Cambridge University

    30 Aug 2016
    Tom Kirk
    tdk25@cam.ac.uk

    1
    Image of “amyloid fibrils”; thread-like structures which form after the protein alpha-synuclein aggregates. Plaques (protein deposits) consisting of this protein have been found in the brains of Parkinson ’s Disease patients and linked to disease. Credit: Patrick Flagmeier

    In a new study, a team of academics at the Centre for Misfolding Diseases, in the Department of Chemistry at the University of Cambridge, show that tiny changes in the amino acid sequence of the protein alpha-synuclein can have a dramatic effect on microscopic processes leading to its aggregation that may occur in the brain, eventually resulting in someone being diagnosed with Parkinson’s Disease.

    Alpha-synuclein is a protein made up of 140 amino acids, and under normal circumstances plays an important part in helping with the smooth flow of chemical signals in the brain.

    Parkinson’s Disease is thought to arise because, for reasons researchers still do not fully understand, the same protein sometimes malfunctions. Instead of adopting the specific structural form needed to do its job, it misfolds and begins to cluster, creating toxic, thread-like structures known as amyloid fibrils. In the case of Parkinson’s Disease, these protein deposits are referred to as Lewy-bodies.

    The new study examined mutated forms of alpha-synuclein which have been found in people from families with a history of Parkinson’s Disease. In all cases, these mutations involved just one change to the protein’s amino acid sequence.

    Although the differences in the sequence are small, the researchers found that they can have a profound effect on how quickly or slowly fibrils start to form. They also found that the mutations strongly influence a process called “secondary nucleation”, in which new fibrils are formed, in an auto-catalytic manner, at the surface of existing ones and thus enable the disease to spread.

    The study stresses that these findings do not explain why humans get the disease. Parkinson’s Disease does not always emerge as a result of the mutations and has multiple, complex causes, which are not fully understood.

    Patrick Flagmeier, a PhD student at St John’s College, University of Cambridge, and the study’s lead author, said: “As a finding, it helps us to understand fundamental things about the system by which this disease emerges. In the end, if we can understand all of this better, that can help us to develop therapeutic strategies to confront it. Our hope is that this study will contribute to the global effort towards comprehending why people with these mutations get the disease more frequently, or at a younger age.”

    Although people who do not have mutated forms of alpha-synuclein can still develop Parkinson’s Disease, the five mutations studied by the research team were already known as “familial” variants – meaning that they recur in families where the disease has emerged, and seem to increase the likelihood of its onset.

    What was not clear, until now, is why they have this effect. “We wanted to know how these specific changes in the protein’s sequence influence its behaviour as it aggregates into fibrils,” Flagmeier said.

    To understand this, the researchers conducted lab tests in which they added each of the five mutated forms of alpha-synuclein, as well as a standard version of the protein, to samples simulating the initiation of fibril formation, their growth and their proliferation.

    The first round of tests examined the initiation of aggregation, using artificial samples recreating conditions in which misfolded alpha-synuclein attaches itself to small structures that are present inside brain cells called lipid vesicles, and then begins to cluster.

    The researchers then tested how the different versions of the protein influence the ability of pre-formed fibrils to extend and grow. Finally, they tested the impact of mutated proteins on secondary nucleation, in which, under specific conditions, the fibrils can multiply and start to spread.

    Overall, the tests revealed that while the mutated forms of alpha-synuclein do not notably influence the fibril growth, they do have a dramatic effect on both the initial formation of the fibrils, and their secondary nucleation. Some of the mutated forms of the protein made these processes considerably faster, while others made it almost “undetectably slow”, according to the researchers’ report.

    “We have only recently discovered the autocatalytic amplification process of alpha-synuclein fibrils, and the results of the present study will help us to understand in much more detail the mechanism behind this process, and in what ways it differs from the initial formation of aggregates.” said Dr. Alexander Buell, one of the senior authors on the study.

    Why the mutations have this impact remains unclear, but the study opens the door to understanding this in detail by identifying, for the first time, that they have such a dramatic impact on very particular stages of the process.

    Dr. Céline Galvagnion, another of the senior authors on the study, said: “This study quantitatively correlates individual changes in the amino acid sequence of alpha-synuclein with its tendency to aggregate. However, the effect of these mutations on other parameters such as the loss of the protein’s function and the efficiency of clearance of alpha-synuclein needs to be taken into account to fully understand the link between the familial mutations of alpha-synuclein and the onset of Parkinson’s Disease.”

    “The effects we observed were changes of several orders of magnitude and it was unexpected to observe such dramatic effects from single-point mutations,” Flagmeier said. “It seems that these single-point mutations in the sequence of alpha-synuclein play an important role in influencing particular microscopic steps in the aggregation process that may lead to Parkinson’s Disease.”

    The full study, which also involves Professors Chris Dobson and Tuomas Knowles, is published in the journal, Proceedings of the National Academy of Sciences.

    Reference:

    Flagmeier, P. et. al: Mutations associated with familial Parkinson’s disease alter the initiation and amplification steps of α-synuclein aggregation. PNAS (2016): DOI: 10.1073/pnas.1604645113

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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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 12:17 pm on August 24, 2016 Permalink | Reply
    Tags: Astronomers identify a young heavyweight star in the Milky Way, , , U Cambridge   

    From U Cambridge: “Astronomers identify a young heavyweight star in the Milky Way” 

    U Cambridge bloc

    Cambridge University

    22 Aug 2016
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    A young star over 30 times more massive than the Sun could help us understand how the most extreme stars in the Universe are born.
    Credit: A. Smith, Institute of Astronomy, Cambridge

    Astronomers have identified a young star, located almost 11,000 light years away, which could help us understand how the most massive stars in the Universe are formed. This young star, already more than 30 times the mass of our Sun, is still in the process of gathering material from its parent molecular cloud, and may be even more massive when it finally reaches adulthood.

    The researchers, led by a team at the University of Cambridge, have identified a key stage in the birth of a very massive star, and found that these stars form in a similar way to much smaller stars like our Sun – from a rotating disc of gas and dust. The results will be presented this week at the Star Formation 2016 conference at the University of Exeter, and are reported in the Monthly Notices of the Royal Astronomical Society.

    In our galaxy, massive young stars – those with a mass at least eight times greater than the Sun – are much more difficult to study than smaller stars. This is because they live fast and die young, making them rare among the 100 billion stars in the Milky Way, and on average, they are much further away.

    “An average star like our Sun is formed over a few million years, whereas massive stars are formed orders of magnitude faster — around 100,000 years,” said Dr John Ilee from Cambridge’s Institute of Astronomy, the study’s lead author. “These massive stars also burn through their fuel much more quickly, so they have shorter overall lifespans, making them harder to catch when they are infants.”

    The protostar that Ilee and his colleagues identified resides in an infrared dark cloud – a very cold and dense region of space which makes for an ideal stellar nursery. However, this rich star-forming region is difficult to observe using conventional telescopes, since the young stars are surrounded by a thick, opaque cloud of gas and dust. But by using the Submillimeter Array (SMA) in Hawaii and the Karl G Jansky Very Large Array (VLA) in New Mexico, both of which use relatively long wavelengths of light to observe the sky, the researchers were able to ‘see’ through the cloud and into the stellar nursery itself.

    CfA Submillimeter Array Hawaii SAO
    CfA Submillimeter Array Hawaii SAO

    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA
    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    By measuring the amount of radiation emitted by cold dust near the star, and by using unique fingerprints of various different molecules in the gas, the researchers were able to determine the presence of a ‘Keplerian’ disc – one which rotates more quickly at its centre than at its edge.

    “This type of rotation is also seen in the Solar System – the inner planets rotate around the Sun more quickly than the outer planets,” said Ilee. “It’s exciting to find such a disc around a massive young star, because it suggests that massive stars form in a similar way to lower mass stars, like our Sun.”

    The initial phases of this work were part of an undergraduate summer research project at the University of St Andrews, funded by the Royal Astronomical Society (RAS). The undergraduate carrying out the work, Pooneh Nazari, said, “My project involved an initial exploration of the observations, and writing a piece of software to ‘weigh’ the central star. I’m very grateful to the RAS for providing me with funding for the summer project — I’d encourage anyone interested in academic research to try one!”

    From these observations, the team measured the mass of the protostar to be over 30 times the mass of the Sun. In addition, the disc surrounding the young star was also calculated to be relatively massive, between two and three times the mass of our Sun. Dr Duncan Forgan, also from St Andrews and lead author of a companion paper, said, “Our theoretical calculations suggest that the disc could in fact be hiding even more mass under layers of gas and dust. The disc may even be so massive that it can break up under its own gravity, forming a series of less massive companion protostars.”

    The next step for the researchers will be to observe the region with the Atacama Large Millimetre Array (ALMA), located in Chile. This powerful instrument will allow any potential companions to be seen, and allow researchers to learn more about this intriguing young heavyweight in our galaxy.

    This work has been supported by a grant from the European Research Council.

    References:
    J.D. Ilee et al. ‘G11.92-0361 MM1: A Keplerian disc around a massive young proto O-star. Monthly Notices of the Royal Astronomical Society (2016): DOI: 10.1093/mnras/stw1912

    D. H. Forgan et al. Self-gravitating disc candidates around massive young stars. Monthly Notices of the Royal Astronomical Society (2016): DOI: 10.1093/mnras/stw1917

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    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 1:26 pm on August 11, 2016 Permalink | Reply
    Tags: , , , , U Cambridge   

    From U Cambridge: “Gene signature in healthy brains pinpoints the origins of Alzheimer’s disease” 

    U Cambridge bloc

    Cambridge University

    10 Aug 2016
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    In healthy tissues, a gene expression signature associated with amyloid-beta and tau aggregation echoes the progression of AD well before the onset of the disease. Credit: J. Freer

    A specific gene expression pattern maps out which parts of the brain are most vulnerable to Alzheimer’s disease, decades before symptoms appear, and helps define the molecular origins of the disease.

    Researchers have discovered a gene signature in healthy brains that echoes the pattern in which Alzheimer’s disease spreads through the brain much later in life. The findings, published in the journal Science Advances, could help uncover the molecular origins of this devastating disease, and may be used to develop preventative treatments for at-risk individuals to be taken well before symptoms appear.

    The results, by researchers from the University of Cambridge, identified a specific signature of a group of genes in the regions of the brain which are most vulnerable to Alzheimer’s disease. They found that these parts of the brain are vulnerable because the body’s defence mechanisms against the proteins partly responsible for Alzheimer’s disease are weaker in these areas.

    Healthy individuals with this specific gene signature are highly likely to develop Alzheimer’s disease in later life, and would most benefit from preventative treatments, if and when they are developed for human use.

    Alzheimer’s disease, the most common form of dementia, is characterised by the progressive degeneration of the brain. Not only is the disease currently incurable, but its molecular origins are still unknown. Degeneration in Alzheimer’s disease follows a characteristic pattern: starting from the entorhinal region and spreading out to all neocortical areas. What researchers have long wondered is why certain parts of the brain are more vulnerable to Alzheimer’s disease than others.

    “To answer this question, what we’ve tried to do is to predict disease progression starting from healthy brains,” said senior author Professor Michele Vendruscolo of the Centre for Misfolding Diseases at Cambridge’s Department of Chemistry. “If we can predict where and when neuronal damage will occur, then we will understand why certain brain tissues are vulnerable, and get a glimpse at the molecular origins of Alzheimer’s disease.”

    One of the hallmarks of Alzheimer’s disease is the build-up of protein deposits, known as plaques and tangles, in the brains of affected individuals. These deposits, which accumulate when naturally-occurring proteins in the body fold into the wrong shape and stick together, are formed primarily of two proteins: amyloid-beta and tau.

    “We wanted to know whether there is something special about the way these proteins behave in vulnerable brain tissue in young individuals, long before the typical age of onset of the disease,” said Vendruscolo.

    Vendruscolo and his colleagues found that part of the answer lay within the mechanism of control of amyloid-beta and tau. Through the analysis of more than 500 samples of healthy brain tissues from the Allen Brain Atlas, they identified a signature of a group of genes in healthy brains. When compared with tissue from Alzheimer’s patients, the researchers found that this same pattern is repeated in the way the disease spreads in the brain.

    “Vulnerability to Alzheimer’s disease isn’t dictated by abnormal levels of the aggregation-prone proteins that form the characteristic deposits in disease, but rather by the weaker control of these proteins in the specific brain tissues that first succumb to the disease,” said Vendruscolo.

    Our body has a number of effective defence mechanisms which protect it against protein aggregation, but as we age, these defences get weaker, which is why Alzheimer’s generally occurs in later life. As these defence mechanisms, collectively known as protein homeostasis systems, get progressively impaired with age, proteins are able to form more and more aggregates, starting from the tissues where protein homeostasis is not so strong in the first place.

    Earlier this year, the same researchers behind the current study identified a possible ‘neurostatin’ that could be taken by healthy individuals in order to slow or stop the progression of Alzheimer’s disease, in a similar way to how statins are taken to prevent heart disease. The current results suggest a way to exploit the gene signature to identify those individuals most at risk and who would most benefit from taking a neurostatin in earlier life.

    Although a neurostatin for human use is still quite some time away, a shorter-term benefit of these results may be the development of more effective animal models for the study of Alzheimer’s disease. Since the molecular origins of the disease have been unknown to date, it has been difficult to breed genetically modified mice or other animals that repeat the full pathology of Alzheimer’s disease, which is the most common way for scientists to understand this or any disease in order to develop new treatments.

    “It is exciting to consider that the molecular origins identified here for Alzheimer’s may predict vulnerability for other diseases associated with aberrant aggregation – such as ALS, Parkinson’s and frontotemporal dementia,” said Rosie Freer, a PhD student in the Department of Chemistry and the study’s lead author. “I hope that these results will help drug discovery efforts – that by illuminating the origin of disease vulnerability, there will be a clearer target for those working to cure Alzheimer’s.”

    “The results of this particular study provide a clear link between the key factors that we have identified as underlying the aggregation phenomenon and the order in which the effects of Alzheimer’s disease are known to spread through the different regions of the brain,” said study co-author Professor Christopher Dobson, who is Master of St John’s College, Cambridge. “Linking the properties of specific protein molecules to the onset and spread of neuronal damage is a crucial step in the quest to find effective drugs to combat this dreadful neurodegenerative condition, and potentially other diseases related to protein misfolding and aggregation.”

    Addressing these problems represents the core programme of research of the Centre for Misfolding Diseases, which is directed by Chris Dobson, Tuomas Knowles and Michele Vendruscolo. The primary mission of the Centre is to develop a fundamental understanding of the molecular origins of the variety of disorders associated with the misfolding and aggregation of proteins, which include Parkinson’s disease, ALS and type II diabetes as well as Alzheimer’s disease, and then to use such understanding for the rational design of novel therapeutic strategies.

    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 12:49 pm on August 8, 2016 Permalink | Reply
    Tags: , Liquid light switch could enable more powerful electronics, U Cambridge   

    From U Cambridge: “Liquid light switch could enable more powerful electronics” 

    U Cambridge bloc

    Cambridge University

    1
    Polariton fluid emits clockwise or anticlockwise spin light by applying electric fields to a semiconductor chip. Credit: Alexander Dreismann

    Researchers have built a miniature electro-optical switch which can change the spin – or angular momentum – of a liquid form of light by applying electric fields to a semiconductor device a millionth of a metre in size. Their results, reported in the journal Nature Materials, demonstrate how to bridge the gap between light and electricity, which could enable the development of ever faster and smaller electronics.

    There is a fundamental disparity between the way in which information is processed and transmitted by current technologies. To process information, electrical charges are moved around on semiconductor chips; and to transmit it, light flashes are sent down optical fibres. Current methods of converting between electrical and optical signals are both inefficient and slow, and researchers have been searching for ways to incorporate the two.

    In order to make electronics faster and more powerful, more transistors need to be squeezed onto semiconductor chips. For the past 50 years, the number of transistors on a single chip has doubled every two years – this is known as Moore’s law. However, as chips keep getting smaller, scientists now have to deal with the quantum effects associated with individual atoms and electrons, and they are looking for alternatives to the electron as the primary carrier of information in order to keep up with Moore’s law and our thirst for faster, cheaper and more powerful electronics.

    The University of Cambridge researchers, led by Professor Jeremy Baumberg from the NanoPhotonics Centre, in collaboration with researchers from Mexico and Greece, have built a switch which utilises a new state of matter called a Polariton Bose-Einstein condensate in order to mix electric and optical signals, while using miniscule amounts of energy.

    Polariton Bose-Einstein condensates are generated by trapping light between mirrors spaced only a few millionths of a metre apart, and letting it interact with thin slabs of semiconductor material, creating a half-light, half-matter mixture known as a polariton.

    Putting lots of polaritons in the same space can induce condensation – similar to the condensation of water droplets at high humidity – and the formation of a light-matter fluid which spins clockwise (spin-up) or anticlockwise (spin-down). By applying an electric field to this system, the researchers were able to control the spin of the condensate and switch it between up and down states. The polariton fluid emits light with clockwise or anticlockwise spin, which can be sent through optical fibres for communication, converting electrical to optical signals.

    “The polariton switch unifies the best properties of electronics and optics into one tiny device that can deliver at very high speeds while using minimal amounts of power,” said the paper’s lead author Dr Alexander Dreismann from Cambridge’s Cavendish Laboratory.

    “We have made a field-effect light switch that can bridge the gap between optics and electronics,” said co-author Dr Hamid Ohadi, also from the Cavendish Laboratory. “We’re reaching the limits of how small we can make transistors, and electronics based on liquid light could be a way of increasing the power and efficiency of the electronics we rely on.”

    While the prototype device works at cryogenic temperatures, the researchers are developing other materials that can operate at room temperature, so that the device may be commercialised. The other key factor for the commercialisation of the device is mass production and scalability. “Since this prototype is based on well-established fabrication technology, it has the potential to be scaled up in the near future,” said study co-author Professor Pavlos Savvidis from the FORTH institute in Crete, Greece.

    The team is currently exploring options for commercialising the technology as well as integrating it with the existing technology base.

    The research is funded as part of a UK Engineering and Physical Sciences Research Council (EPSRC) investment in the Cambridge NanoPhotonics Centre, as well as the European Research Council (ERC) and the Leverhulme Trust.

    See the full article here .

    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 7:44 am on August 6, 2016 Permalink | Reply
    Tags: , , , U Cambridge   

    From U Cambridge: “Carbon dioxide can be stored underground for ten times the length needed to avoid climatic impact” 

    U Cambridge bloc

    Cambridge University

    28 Jul 2016
    Jennifer Hayward
    jeh98@cam.ac.uk

    1
    Study of natural-occurring 100,000 year-old CO2 reservoirs shows no significant corroding of ‘cap rock’, suggesting the greenhouse gas hasn’t leaked back out – one of the main concerns with greenhouse gas reduction proposal of carbon capture and storage.

    New research shows that natural accumulations of carbon dioxide (CO2) that have been trapped underground for around 100,000 years have not significantly corroded the rocks above, suggesting that storing CO2 in reservoirs deep underground is much safer and more predictable over long periods of time than previously thought.

    These findings, published today in the journal Nature Communications, demonstrate the viability of a process called carbon capture and storage (CCS) as a solution to reducing carbon emissions from coal and gas-fired power stations, say researchers.

    CCS involves capturing the carbon dioxide produced at power stations, compressing it, and pumping it into reservoirs in the rock more than a kilometre underground.

    The CO2 must remain buried for at least 10,000 years to avoid the impacts on climate. One concern is that the dilute acid, formed when the stored CO2 dissolves in water present in the reservoir rocks, might corrode the rocks above and let the CO2 escape upwards.

    By studying a natural reservoir in Utah, USA, where CO2 released from deeper formations has been trapped for around 100,000 years, a Cambridge-led research team has now shown that CO2 can be securely stored underground for far longer than the 10,000 years needed to avoid climatic impacts.

    Their new study shows that the critical component in geological carbon storage, the relatively impermeable layer of “cap rock” that retains the CO2, can resist corrosion from CO2-saturated water for at least 100,000 years.

    “Carbon capture and storage is seen as essential technology if the UK is to meet its climate change targets,” says principle investigator Professor Mike Bickle, Director of the Cambridge Centre for Carbon Capture and Storage at the University of Cambridge.

    “A major obstacle to the implementation of CCS is the uncertainty over the long-term fate of the CO2 which impacts regulation, insurance, and who assumes the responsibility for maintaining CO2 storage sites. Our study demonstrates that geological carbon storage can be safe and predictable over many hundreds of thousands of years.”

    The key component in the safety of geological storage of CO2 is an impermeable cap rock over the porous reservoir in which the CO2 is stored. Although the CO2 will be injected as a dense fluid, it is still less dense than the brines originally filling the pores in the reservoir sandstones, and will rise until trapped by the relatively impermeable cap rocks.

    “Some earlier studies, using computer simulations and laboratory experiments, have suggested that these cap rocks might be progressively corroded by the CO2-charged brines, formed as CO2 dissolves, creating weaker and more permeable layers of rock several metres thick and jeopardising the secure retention of the CO2,” explains lead author Dr Niko Kampman.

    “However, these studies were either carried out in the laboratory over short timescales or based on theoretical models. Predicting the behaviour of CO2 stored underground is best achieved by studying natural CO2 accumulations that have been retained for periods comparable to those needed for effective storage.”

    To better understand these effects, this study, funded by the UK Natural Environment Research Council and the UK Department of Energy and Climate Change, examined a natural reservoir where large natural pockets of CO2 have been trapped in sedimentary rocks for hundreds of thousands of years. Sponsored by Shell, the team drilled deep down below the surface into one of these natural CO2 reservoirs to recover samples of the rock layers and the fluids confined in the rock pores.

    The team studied the corrosion of the minerals comprising the rock by the acidic carbonated water, and how this has affected the ability of the cap rock to act as an effective trap over geological periods of time. Their analysis studied the mineralogy and geochemistry of cap rock and included bombarding samples of the rock with neutrons at a facility in Germany to better understand any changes that may have occurred in the pore structure and permeability of the cap rock.

    They found that the CO2 had very little impact on corrosion of the minerals in the cap rock, with corrosion limited to a layer only 7cm thick. This is considerably less than the amount of corrosion predicted in some earlier studies, which suggested that this layer might be many metres thick.

    The researchers also used computer simulations, calibrated with data collected from the rock samples, to show that this layer took at least 100,000 years to form, an age consistent with how long the site is known to have contained CO2.

    The research demonstrates that the natural resistance of the cap rock minerals to the acidic carbonated waters makes burying CO2 underground a far more predictable and secure process than previously estimated.

    “With careful evaluation, burying carbon dioxide underground will prove very much safer than emitting CO2 directly to the atmosphere,” says Bickle.

    The Cambridge research into the CO2 reservoirs in Utah was funded by the Natural Environment Research Council (CRIUS consortium of Cambridge, Manchester and Leeds universities and the British Geological Survey) and the Department of Energy and Climate Change.

    The project involved an international consortium of researchers led by Cambridge, together with Aarchen University (Germany), Utrecht University (Netherlands), Utah State University (USA), the Julich Centre for Neutron Science, (Garching, Germany), Oak Ridge National Laboratory (USA), the British Geological Survey, and Shell Global Solutions International (Netherlands).

    Reference:

    N. Kampman, et al. “Observational evidence confirms modelling of the long-term integrity of CO2-reservoir caprocks” Nature Communications 28 July 2016.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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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 4:17 pm on July 12, 2016 Permalink | Reply
    Tags: , , , Gravitational vortex, , U Cambridge   

    From U Cambridge: “Gravitational vortex provides new way to study matter close to a black hole” 

    U Cambridge bloc

    Cambridge University

    12 Jul 2016
    No writer credit found

    1
    Illustration of gravitational vortex. Credit: ESA/ATG medialab

    An international team of astronomers has proved the existence of a ‘gravitational vortex’ around a black hole, solving a mystery that has eluded astronomers for more than 30 years. The discovery will allow astronomers to map the behaviour of matter very close to black holes. It could also open the door to future investigation of Albert Einstein’s general relativity.

    Matter falling into a black hole heats up as it plunges to its doom. Before it passes into the black hole and is lost from view forever, it can reach millions of degrees. At that temperature it shines x-rays into space.

    In the 1980s, astronomers discovered that the x-rays coming from black holes vary on a range of timescales and can even follow a repeating pattern with a dimming and re-brightening taking 10 seconds to complete. As the days, weeks and then months progress, the pattern’s period shortens until the oscillation takes place 10 times every second. Then it suddenly stops altogether.

    This phenomenon was dubbed a Quasi Periodic Oscillation (QPO). During the 1990s, astronomers began to suspect that the QPO was associated with a gravitational effect predicted by Einstein’s general relativity which suggested that a spinning object will create a kind of gravitational vortex. The effect is similar to twisting a spoon in honey: anything embedded in the honey will be ‘dragged’ around by the twisting spoon. In reality, this means that anything orbiting around a spinning object will have its motion affected. If an object is orbiting at an angle, its orbit will ‘precess’ – in other words, the whole orbit will change orientation around the central object. The time for the orbit to return to its initial condition is known as a precession cycle.

    In 2004, NASA launched Gravity Probe B to measure this so-called Lense-Thirring effect around Earth.

    NASA/Gravity Probe B
    NASA/Gravity Probe B

    By analysing the resulting data, scientists confirmed that the spacecraft would turn through a complete precession cycle once every 33 million years. Around a black hole, however, the effect would be much stronger because of the stronger gravitational field: the precession cycle would take just a matter of seconds to complete, close to the periods of the QPOs.

    An international team of researchers, including Dr Matt Middleton from the Institute of Astronomy at the University of Cambridge, has used the European Space Agency’s XMM-Newton and NASA’s NuSTAR, both x-ray observatories, to study the effect of black hole H1743-322 on a surrounding flat disc of matter known as an ‘accretion disk’.

    ESA/XMM Newton
    ESA/XMM Newton

    NASA/NuSTAR
    NASA/NuSTAR

    Close to a black hole, the accretion disc puffs up into a hot plasma, a state of matter in which electrons are stripped from their host atoms – the precession of this puffed up disc has been suspected to drive the QPO. This can also explain why the period changes – the place where the disc puffs up gets closer to the black hole over weeks and months, and, as it gets closer to the black hole, the faster its Lense-Thirring precession becomes.

    2

    The plasma releases high energy radiation that strikes the matter in the surrounding accretion disc, making the iron atoms in the disc shine like a fluorescent light tube. Instead of visible light, the iron releases X-rays of a single wavelength – referred to as ‘a line’. Because the accretion disc is rotating, the iron line has its wavelength distorted by the Doppler effect: line emission from the approaching side of the disc is squashed – blue shifted – and line emission from the receding disc material is stretched – red shifted. If the plasma really is precessing, it will sometimes shine on the approaching disc material and sometimes on the receding material, making the line wobble back and forth over the course of a precession cycle.

    It is this ‘wobble’ that has been observed by the researchers.

    “Just as general relativity predicts, we’ve seen the iron line wobble as the accretion disk orbits the black hole,” says Dr Middleton. “This is what we’d expect from matter moving in a strong gravitational field such as that produced by a black hole.”

    This is the first time that the Lense-Thirring effect has been measured in a strong gravitational field. The technique will allow astronomers to map matter in the inner regions of accretion discs around back holes. It also hints at a powerful new tool with which to test general relativity. Einstein’s theory is largely untested in such strong gravitational fields. If astronomers can understand the physics of the matter that is flowing into the black hole, they can use it to test the predictions of general relativity as never before – but only if the movement of the matter in the accretion disc can be completely understood.

    “We need to test Einstein’s general theory of relativity to breaking point,” adds Dr Adam Ingram, the lead author at the University of Amsterdam. “That’s the only way that we can tell whether it is correct or, as many physicists suspect, an approximation – albeit an extremely accurate one.”

    Larger X-ray telescopes in the future could help in the search because they could collect the X-rays faster. This would allow astronomers to investigate the QPO phenomenon in more detail. But for now, astronomers can be content with having seen Einstein’s gravity at play around a black hole.

    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 7:12 am on July 12, 2016 Permalink | Reply
    Tags: , , U Cambridge   

    From U Cambridge: “Where did it all go wrong? Scientists identify ‘cell of origin’ in skin cancers” 

    U Cambridge bloc

    Cambridge University

    08 Jul 2016
    Craig Brierley
    Craig.Brierley@admin.cam.ac.uk

    1
    Basal cell carcinoma in mouse tail epidermis derived from a single mutant stem cell. Credit: Adriana Sánchez-Danés

    Scientists have identified for the first time the ‘cell of origin’ – in other words, the first cell from which the cancer grows – in basal cell carcinoma, the most common form of skin cancer, and followed the chain of events that lead to the growth of these invasive tumours.

    Our skin is kept healthy by a constant turnover, with dying skin cells being shed and replaced by new cells. The process is maintained by ‘progenitor’ cells – the progeny of stem cells – that divide and ‘differentiate’ into fully-functional skin cells to replenish dying skin. These cells are in turn supported by a smaller population of ‘stem cells’, which remain silent, ready to become active and repair skin when it becomes damaged.

    However, when this process goes awry, cancers can arise: damaged DNA or the activation of particular genes known as ‘oncogenes’ can trigger a cascade of activity that can lead ultimately to unchecked proliferation, the hallmark of a cancer. In some cases, these tumours may be benign, but in others, they can spread throughout the body – or ‘metastasise’ – where they can cause organ failure.

    Until now, there has been intense interest in the scientific field about which types of cell – stem cell, progenitor cell or both – can give rise to tumours, and how those cells become transformed in the process of tumour initiation and growth. Now, in a study published in Nature, researchers led by Professor Cédric Blanpain at the Université Libre de Bruxelles, Belgium, and Professor Ben Simons at the University of Cambridge, have demonstrated in mice how skin stem and progenitor cells respond to the activation of an oncogene. Their studies have shown that, while progenitor cells can give rise to benign lesions, only stem cells have the capacity to develop into deadly invasive tumours.

    The researchers used a transgenic mouse model – a mouse whose genes had been altered to allow the activation of an oncogene in individual stem and progenitor cells. The oncogene was coupled with a fluorescent marker so that cells in which the oncogene was active could be easily identified, and as these cells proliferate, their ‘daughter’ cells could also be tracked. These related, fluorescent cells are known as ‘clones’.

    By analysing the number of fluorescently-labelled cells per clone using mathematical modelling, the team was able to show that only clones derived from mutant stem cells were able to overcome a mechanism known as ‘apoptosis’, or programmed cell death, and continue to divide and proliferate unchecked, developing into a form of skin cancer known as basal cell carcinoma. In contrast, the growth of clones derived from progenitor cells becomes checked by increasing levels of apoptosis, leading to the formation of benign lesions.

    “It’s incredibly rare to identify a cancer cell of origin and until now no one has been able to track what happens on an individual level to these cells as they mutate and proliferate,” says Professor Blanpain. “We now know that stem cells are the culprits: when an oncogene in a stem cell becomes active, it triggers a chain reaction of cell division and proliferation that overcomes the cell’s safety mechanisms.”

    “While this has solved a long-standing scientific argument about which cell types can lead to invasive skin tumours, it is far more than just a piece of esoteric knowledge,” adds Professor Simons from the Cavendish Laboratory at the University of Cambridge. “It suggests to us that targeting the pathways used in regulating cell fate decisions – how stem cells choose between cell proliferation and differentiation – could be a more effective way of halting tumours in their tracks and lead to potential new therapies.”

    The work was supported by the FNRS, TELEVIE, the Fondation Contre le Cancer, the ULB fondation, the foundation Bettencourt Schueller, the foundation Baillet Latour, the European Research Council, Wellcome Trust and Trinity College Cambridge.

    Reference
    Sánchez-Danés, A et al. Defining the clonal dynamics leading to mouse skin tumour initiation. Nature; 8 July 2016; DOI: 10.1038/nature19069

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    U Cambridge Campus

    The University of Cambridge[note 1] (abbreviated as Cantab in post-nominal letters[note 2]) 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.[6] It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk.[7] 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.[8] 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.[9] 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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