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  • richardmitnick 12:08 pm on July 31, 2018 Permalink | Reply
    Tags: Book review, , NATURE   

    From Nature: “Ideal witness: a physicist takes on the world” 

    Nature Mag
    From Nature

    30 July 2018

    Robert P. Crease enjoys Steven Weinberg’s rationalist view of science and its history.

    Part of the ring tunnel at the Large Hadron Collider near Geneva, Switzerland.Credit: Thomas Pflaum/VISUM/eyevine

    Third Thoughts Steven Weinberg Belknap (2018)

    In his 1974 book The First Three Minutes (1977), physicist and Nobel laureate Steven Weinberg pictured his ideal reader as “a smart old attorney” who might not know much science, but “expects nonetheless to hear some convincing arguments”. That’s still his approach in Third Thoughts. This essay collection (his third for a lay readership, hence the title), ranges widely over science, the history of science and current affairs, taking on everything from dark energy and quantum field theory to socio-economic inequity and the wastefulness of crewed space missions.

    Steven Weinberg, U Texas, Larry D. Moore CC BY-SA 3.0., https://en.wikipedia.org/wiki/File:Steven_weinberg_2010.jpg

    The volume mixes new pieces with others previously published in The New York Review of Books. Weinberg acknowledges the help he received from the review’s formidable editor, the late Robert Silvers. He clearly apprenticed well: if his ideal reader is an astute lawyer, Weinberg might be described as an ideal witness. He is clear, to the point, frank and transparent about his perspective — “rationalist, realist, reductionist, and devoutly secular”.

    Among half a dozen pieces on particle physics are lucid explications of, for instance, the Higgs boson, Hilbert space and the Large Hadron Collider. Weinberg has a knack for capturing a complex concept in a succinct, unforgettable image. He compares quantum superposition, in which a particle has two states at once, to a musical chord; when measurement collapses the particle to one state, it “somehow shifts all the intensity of the chord to one of the notes, which we then hear on its own”. And he describes the discovery that nature obeys symmetries whose consequences can be worked out as “like having a spy in the enemy’s high command”.

    A few of the essays delve into history. Weinberg has irked professionals in the field by venturing into their territory, but not because he gets his facts wrong. As a self-confessed ‘Whig’ historian, he believes that the past should be judged by values of the present (the term springs from the name of the long-defunct British political party whose members thought history had been building towards Parliamentary government). Weinberg offers a curious panorama that demotes certain canonical figures, such as Democritus, Francis Bacon and René Descartes.

    The ancient Greek philosopher Democritus didn’t make observations, so, although he correctly proposed that matter is made of atoms, Weinberg argues that he “was wrong about how to learn about the world”. Yet Democritus is of supreme importance for the understanding of science history (as Weinberg admits) because he inspired atomic theorists of the early modern period, such as Robert Boyle and other corpuscular philosophers, in their efforts to explain nature without using theology or teleology. Similarly, Bacon and Descartes, although sometimes scientifically misguided by today’s standards, were vastly important for ushering in the mechanical thinking that Weinberg himself practises. Two essays here convey Weinberg’s responses to critics of his Whig convictions, but I wish he had put the arguments and counter-arguments more forcefully and at greater length.

    Weinberg is at his most interesting when probing the big uncertainties in physics. Ultimately, he is not sure, for instance, that he knows what an ‘elementary particle’ actually is, or how best to interpret quantum mechanics. These moments reveal Weinberg’s considerable integrity, where — as one of the smartest and most diligent scientists around — he describes himself as somewhat lost. He has surveyed the present, and all the best paths forward proposed by other scientists; yet, at gut level, he is confident that nothing on the horizon is fully satisfactory, and that other possibilities might be out there. These admissions imply that Weinberg suspects future historians may harbour a perception of today’s thinking very different from ours.

    The articles on public and personal matters — Weinberg’s thoughts about taxes, his disappointment with former US President Barack Obama for failing to confront economic disparities more directly, and educators who are honoured with burial in Texas State Cemetery — are less interesting. Yet here, as elsewhere, he is clever: “The only technology for which the manned space flight program is well suited is the technology of keeping people alive in space. And the only demand for that technology is in the manned space flight program itself.”

    I read the penultimate essay with anticipation. Weinberg reveals in the introduction that he had not published it before because nobody who read it liked it. You can see why. It’s an earnest piece of amateur philosophizing that compares creativity in theoretical physics to that in the arts, building on Weinberg’s feeling that success in each depends on “a sense of inevitability”. He would have been clearer had he consulted a few philosophical concepts, such as Immanuel Kant’s idea that a beautiful work creates the feeling that it has the inevitability of a product of nature. But Weinberg (whose 1992 book Dreams of a Final Theory contains a chapter entitled ‘Against Philosophy’) was not about to take that route. In all these essays, his directness both enlightens and illuminates flaws in his own arguments. Witnesses, of course — even ideal ones — have blind spots. The best thing about Weinberg’s essays is that they do, indeed, make you feel like a smart old attorney.

    See the full article here .


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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

  • richardmitnick 11:07 am on November 15, 2017 Permalink | Reply
    Tags: , But scientists contacted by Nature have raised concerns about CSNS’s location saying that Dongguan lacks services and infrastructure such as schools and universities that will persuade top scientist, China fires up next-generation neutron-science facility, NATURE, , , Spallation neutron sources produce neutrons by slamming protons onto a metal target — CSNS uses tungsten   

    From Nature: “China fires up next-generation neutron-science facility” 

    Nature Mag

    14 November 2017
    David Cyranoski

    Beam generator puts country in elite company for doing experiments in materials science and other fields.

    Engineers work on an instrument at the China Spallation Neutron Source in Dongguan. Jin Liwang/Xinhua via ZUMAPRESS

    China is revving up its next-generation neutron generator and will soon start experiments there. That will lift the country into a select group of nations with facilities that produce intense neutron beams to study the structure of materials.

    The China Spallation Neutron Source (CSNS) in Dongguan, a 2.2-billion-yuan (US$331-million) centre, will allow the country’s growing pool of top-notch physicists and material scientists, along with international collaborators, to compete in multiple physics and engineering fields. Its designers also hope that the facility will lead to commercial products and applications ranging from batteries and bridges to aeroplane engines and cancer therapy.

    “It is not only a big step forward for Chinese scientists, but also a significant event for the international scientist community,” says Wang Xun-Li, a physicist at the City University of Hong Kong who has been involved in planning the facility.

    Beam bombardment

    Spallation neutron sources produce neutrons by slamming protons onto a metal target — CSNS uses tungsten. They are more cost effective and safer than other methods, which use nuclear reactors to produce neutron beams. As neutrons have no charge, they can penetrate materials more easily than some other probing methods, and they are more senstive to light elements such as hydrogen, making them useful for evaluating candidate materials for fuel cells. Similar facilities exist only in the United Kingdom, United States, Japan and Switzerland, and one is under construction in Sweden.

    Fujio Maekawa, a specialist in neutron sources at the Japan Proton Accelerator Research Complex in Tokaimura, says that although the CSNS delivers neutrons at a lower density than other spallation sources — which means that experiments will take longer — a planned upgrade will bring it in line with other facilities. And given their scarcity, “neutron users around the world always welcome new sources”, he says.

    The CSNS will have capacity to host 20 beam lines, supplying as many instruments. Preliminary tests of its first three instruments began on 1 November. “Neutrons arrived at the samples as expected,” says Wang Fangwei, head of the neutron-science division at CSNS. Although debugging might take a couple of years, he expects the instruments to be calibrated and ready for initial experiments by the end of 2017.

    Chinese physicists are eager to use the facility to analyse the underlying magnetic properties of materials, an area in which the country has significant experience. Wang Xun-Li says that several planned instruments will give scientists the chance to move to the forefront of fields such as the physics of skyrmions — vortex-like excitations in magnetic materials — and high-temperature superconductivity. “There are a whole bunch of early- to mid-career scientists who are hungry to use the facility for studying magnetism,” says Wang Xun-Li.

    Global appeal

    Wang Xun-Li thinks that the latest facility will encourage Chinese researchers to remain in the country instead of pursuing careers elsewhere. “In the past, it was common to see Chinese scientists go abroad for these kinds of studies,” he says.

    The facility’s first instruments are also attracting international researchers. German material scientist Frank Klose says that the CSNS was a major factor when he and material scientist Christine Rehm, his wife, decided to join the new Guangdong Technion Israel Institute of Technology in Shantou, 400 kilometres east of Dongguan. Klose’s research focuses on designing data-storage devices and sensors that could be used in hydrogen-powered cars. He helped design one of the facility’s instruments to investigate the magnetic properties of spintronic devices, which take advantage of the spin of electrons to store data.

    But scientists contacted by Nature have raised concerns about CSNS’s location, saying that Dongguan lacks services and infrastructure, such as schools and universities, that will persuade top scientists and their families to move there. “I believe CSNS is suffering from a lack of first-grade scientists who actually are based in Dongguan,” says a researcher familiar with the facility, who asked for anonymity because of the sensitivity of the issue. Potential users have also expressed some frustration that only 3 instruments will be ready this year, despite the facility’s capacity to host 20.

    But more instruments are already being built. Shenzhen’s government is funding two that are expected to be ready by the end of 2019, including one designed to model high-pressure environments, such as the Earth’s core. Mao Ho-Kwang, a geophysicist at the Carnegie Institution for Science in Washington DC, is keen to use it to simulate what happens to materials in high-pressure conditions. “The CSNS instruments will be a great asset for Earth, environmental and energy science, as well as physics, chemistry and material science,” says Mao. “I am very excited, and the whole neutron community is getting very excited too”.

    See the full article here .

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

  • richardmitnick 12:59 pm on November 1, 2017 Permalink | Reply
    Tags: Astronomers race to learn from first interstellar asteroid ever seen, , , , , NATURE   

    From Naure: “Astronomers race to learn from first interstellar asteroid ever seen” 

    Nature Mag

    31 October 2017
    Ken Croswell

    Wonky orbit confirms that this visitor isn’t from around here.

    The interstellar asteroid A/2017 U1 (circled) is rushing away from Earth and is currently traversing the Pisces constellation. Alan Fitzsimmons, Queen’s University Belfast/Isaac Newton Group, La Palma.

    Scientists are trying to learn everything that they can from the first interstellar asteroid they have ever observed crossing into our Solar System. Spotted less than two weeks ago, the object is now whizzing across the constellation Pisces and, in a couple of months, will be too faint and far away for even the largest telescopes to see.

    “It’s fascinating,” says astronomer David Jewitt of the University of California, Los Angeles. “We are seeing a body from elsewhere in the Galaxy passing through our Solar System. It’s the first time we’ve seen such a thing.”

    Unfortunately, the asteroid, dubbed A/2017 U1, is dashing away, never to return. “It’s going really fast,” says Jewitt. “So we have a limited time to get any measurements at all.” Astronomers would love to know what it’s made of, but it’s so dim that spectra — light that observers use to determine the compositions of celestial objects — have so far revealed little information1. Nor can anyone say what solar system it came from, or how old it is.

    A curious path

    Researchers with the Pan-STARRS1 telescope atop Haleakala in Maui, Hawaii, spied the first images of the intruder, made during the new Moon, in mid-October.

    Pann-STARS telescope, U Hawaii, Mauna Kea, Hawaii, USA, 4,207 m (13,802 ft) above sea level

    “It didn’t move like comets or asteroids normally do,” says astronomer Rob Weryk at the University of Hawaii at Manoa, who first noticed the object on the morning of 19 October.

    Comets and asteroids usually move on elliptical orbits around the Sun. These orbits have an eccentricity — a measure used to describe orbital shape — of less than 1. But an object zipping through the Solar System from beyond should instead follow a hyperbolic orbit, whose eccentricity exceeds 1.

    The latest observations of the asteroid’s changing position indicate that its orbital eccentricity is a whopping 1.20. “It is virtually certain that the object moves in a hyperbolic trajectory,” says Carlos de la Fuente Marcos, an astronomer at the Complutense University of Madrid.

    The asteroid skirted the Sun on 9 September, when it was inside Mercury’s orbit, and then passed by Earth at a distance of 24 million kilometres on 14 October.

    On the lookout

    Astronomers know little else about the exotic visitor. It’s faint, which means that it’s small: fewer than 400 metres across. And despite its excursion near the Sun, it did not develop a tail — as a comet would — and so astronomers are currently classifying it as an asteroid.

    The path of A/2017 U1, an interstellar object that swung through our Solar System. NASA/JPL-Caltech

    Researchers have anticipated interstellar visitors for years. “We have waited a long time,” says planetary scientist Alan Stern at the Southwest Research Institute in Boulder, Colorado, who studied the matter in the 1990s.

    That expectation is based on the knowledge that the gravitational pulls of the giant planets Jupiter, Saturn, Uranus and Neptune catapulted trillions of comets and asteroids from the young Solar System into interstellar space. Planets in other solar systems presumably did the same, littering interstellar space with rogue objects. “By measuring how many there are sweeping through our Solar System, we can get a gauge of how many are in the entire Galaxy, and how many solar systems have contributed to that population,” says Stern.

    “If one hadn’t been discovered fairly soon, that would start to worry me a bit,” says astronomer David Hughes, emeritus professor at the University of Sheffield, UK.

    The asteroid came from the direction of the constellation Lyra, which is roughly where our Solar System is heading. Given this trajectory, researchers are expecting to see more objects coming from this direction than from elsewhere, just as runners heading into the rain encounter more drops on their chests than their backs.

    A/2017 U1 is the first of many such objects, predicts Jewitt.


    Masiero, J. Preprint at http://arxiv.org/abs/1710.09977 (2017).

    See the full article here .

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

  • richardmitnick 9:35 am on September 27, 2017 Permalink | Reply
    Tags: A new way to hunt for superconductors, , Discovering new states of matter, NATURE, Physicist Gil Lonzarich,   

    From Nature: “A quantum pioneer unlocks matter’s hidden secrets” 

    Nature Mag

    27 September 2017
    Elizabeth Gibney

    Physicist Gil Lonzarich has sparked a revolution in the study of phase transitions driven by quantum fluctuations.

    In 1989, surgery for detached retinas left Gilbert Lonzarich blind for a month. Rather than feel shaken or depressed, the condensed-matter physicist at the University of Cambridge, UK, seized the opportunity, inviting his graduate students to his house to share with them how exciting it was to adapt to life without sight. Lonzarich’s embrace of the experience perfectly captures his approach to life, says Andrew Mackenzie, then one of those students and now a director at the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany. “Gil is one of the most positive people I’ve ever met. He finds interest in everything,” he says.

    For more than 40 years, that optimism and curiosity has led Lonzarich to probe materials in ways never thought possible. In pioneering experiments in the 1990s, his team showed that pushing magnetic compounds to extreme pressures and close to absolute zero can make some of them conduct electricity without resistance [1]. This flew in the face of convention, which declared that magnetism and superconductivity could never mix. “It was as if nowadays you were talking about finding aliens or something,” says Malte Grosche, a colleague at Cambridge.

    That work showed physicists a new way to hunt for superconductors, which lie at the heart of technologies such as magnetic resonance imagers and particle accelerators. In recent years, it has offered a potential explanation for why some materials remain superconductors at temperatures much higher than absolute zero, which could pave the way to developing efficient, cheap devices that superconduct at room temperature.

    But the experiments have had an impact well beyond superconductivity. Lonzarich’s method of subjecting materials to extreme conditions has become a general recipe for discovering new states of matter. Around the world, physicists now use this approach to probe a range of materials in which the collective interactions of electrons can give rise to unusual behaviour. Some of these phenomena could potentially revolutionize computing.

    Lonzarich’s research may be legendary in his community, but the physicist’s humility and generosity are what endear him to his colleagues. He is famously unconscious of time; a casual conversation with Lonzarich can easily lead to an hours-long random walk through the byways of physics, philosophy, politics and history. That might mean a missed lunch, says Michael Sutherland, a Cambridge colleague — “but it’s the most productive few hours you’ll have all week”. Phone calls with peers frequently last into the small hours of the morning, and on the rare occasions when Lonzarich goes to a conference, he invariably attracts a mass of fellow attendees. “People who meet him even once or twice develop a sense of attachment and awe,” says Louis Taillefer, another former student, who is now a physicist at the University of Sherbrooke in Canada.

    At 72, Lonzarich now has a part-time role in the Cambridge quantum-matter group, but he is still making new discoveries by pushing materials to ever-greater extremes. He sees this little-explored realm as just as fundamental to unravelling the laws of physics as the high-energy experiments at particle colliders, and expects that there is plenty more to discover. “Gil has never believed that we’re now just filling in the details,” says Piers Coleman, a theoretical physicist at Rutgers University in Piscataway, New Jersey. “He really views the exploration of quantum matter as a true frontier.”

    Collective efforts

    Walking around a timeworn study at Trinity College, Cambridge, Lonzarich is eager to point out a portrait of the economist John Kenneth Galbraith, one of his heroes, and he talks enthusiastically about the impressive work of his colleagues. But when conversation turns to his own achievements, Lonzarich becomes reticent. It is human nature is to celebrate heroes, he says, but science is a collective activity, and singling out individuals for praise stifles a team.

    Although colleagues are quick to highlight Lonzarich’s influence, he never would — a practice that could be traced back to his upbringing, by Italian parents, on the Istria peninsula. His father told him to “always cut the larger slice of the pie for the other person”, he recalls. At school, he learnt about the Roman Republic and was intrigued by the importance placed on reason, compromise and collaborative governance.

    His family moved to the United States when he was nine. By the 1960s, Lonzarich had grown into a studious young man. His interest in physics began at the University of California, Berkeley, where he earned a liberal arts degree. It was there that he met Gerie Simmons (now Lonzarich). The pair had admired each other from afar before she engineered their meeting by pretending to need a physics tutor; they married in 1967.

    “On the rare occasions I’ve seen pictures of him from those days, he had long hair. He was a physics hippy,” says Coleman. But although Lonzarich felt strongly that people should challenge the government, including the United States’ nascent war in Vietnam, he became disillusioned with the counter-culture’s free use of drugs and rejection of family. “I wanted to be able to do something tangible, to make good use of life. I didn’t think we were doing that,” he says.

    After a they spent a spell at the University of Minnesota in Minneapolis, the darker side of the movement eventually drove Gerie and Gil away from the United States altogether, to the University of British Columbia in Vancouver, Canada. There, Lonzarich became fascinated with magnetism, while working on his PhD in a new laboratory led by condensed-matter physicist Andrew Gold. When he left in 1976 for a stint at Cambridge, he found his new Rome. The collegiate structure had no real hierarchy and boasted two giants of condensed-matter physics — Brian Pippard and David Shoenberg. What was intended to be a one-year European adventure ended up lasting more than 40 years.

    Lonzarich arrived at Cambridge wanting to study magnets — materials in which the spins of electrons all spontaneously align. His approach raised a few eyebrows at first: he developed his own mathematical notation and would spend weeks preparing his experiments while seeming to do nothing. But his methods soon began to bear fruit.

    In magnetic materials, spins maintain their orderly arrangement only up to a point; above a certain temperature, electrons have so much energy that they can easily overcome the forces that cause their spins to align. Lonzarich reckoned that the best way to understand magnetic materials was to push them to that point, where they would be poised on the knife-edge between order and disorder. In particular, he was interested in exploring what might happen if the magnetic transition were shifted so that quantum effects could potentially alter the material’s state. At higher pressures, the transition occurs at lower temperatures. And with enough pressure, a material can be ‘tuned’ so that its magnetic transition point occurs close to absolute zero. Here, thermal vibrations don’t provide enough energy for the material to lose its magnetic order. Instead, quantum fluctuations — transient changes in electron properties, such as velocity and position, caused by the inherent uncertainty of the quantum world — dominate and can cause the material to switch states. In this regime, a region around a spot at absolute zero called the quantum critical point, magnetic materials become unstable and teeter on the brink of magnetism: they lack order but itch to align.

    With larger physical forces suppressed around the quantum critical point, ordinarily weak interactions between electrons could have huge effects. And they might, Lonzarich reasoned, give rise to new states of matter through their collective interaction. “It’s like in a forest; the little plants won’t grow until the big tree is cut down,” he says.

    In particular, Lonzarich predicted that antiferromagnets — magnetic materials in which neighbouring spins align in opposite directions below a certain temperature — would become superconducting near the quantum critical point. On the verge of magnetism, he reasoned, the electrons would be so eager to align that they might spontaneously form pairs with opposite spins. Such antiparallel pairs would stick together, and their attraction to each other would stabilize their journey through the material’s atomic lattice (see ‘Hidden powers‘).



    Since the mid-1980s, various theorists had suggested that such magnetically mediated superconductivity could arise, but Lonzarich’s team was the first to provide solid experimental proof. When the group pushed a sample of the antiferromagnet cerium indium-3 close to the quantum critical point by cooling it at high pressure, the researchers saw it flip into a superconducting phase — something never before seen in a magnetic material1.

    The work, which was performed in 1994, demonstrated a new category of superconductor. It also provided a road map by which to search for other superconducting materials. Today, physicists routinely push the phase transition in magnetic materials down to absolute zero to see whether this behaviour emerges.

    New terrain

    The quantum critical point, and the strong quantum interactions that can take place around it, can give rise to other exotic states, not just superconductivity. “It’s like a breeding ground for discovering new states of matter,” says Cambridge physicist Stephen Rowley. Physicists around the world now manipulate a range of different factors — pressure, magnetic fields and chemical composition — to push phase transitions towards lower temperatures and so approach a quantum critical point.

    In the late 1990s, this method led Lonzarich and then-student Christian Pfleiderer to discover strange behaviour in the material manganese silicide [2]. Experiments done in the past few years have hinted that this may be connected to swirling two-dimensional magnetic vortices, known as skyrmions, that were later described by Pfleiderer and his colleagues [3] and are now being touted as a super-efficient way to store information. By probing around a quantum critical point of strontium ruthenate oxide, in 2007 Mackenzie and his team confirmed the existence of a new phase of matter, in which electrons flow but still show an orderly spatial structure [4].

    Fellow physicists say Lonzarich is unique in that he is not only a good theorist but also an exceptional experimenter. “You have to look back to Enrico Fermi to someone able to think so deeply about theory and do really good experiments,” says David Pines, a physicist and distinguished research professor at the University of California, Davis. Lonzarich grows his own samples to extreme levels of purity and pioneered a technique, known as quantum oscillation, that allows physicists to determine the electronic structure of complex, interacting systems [5]. Patricia Alireza, who runs the high-pressure laboratory at Cambridge’s Cavendish Laboratory, says that Lonzarich will often encourage her to create devices that squeeze samples well beyond what was thought possible. “Gil will smile and say, ‘I think we could probably do a factor of 100 better than that’,” she says. “And you know what? We always do.”

    Many of Lonzarich’s students have continued in physics and flourished. Suchitra Sebastian, for example, led work with Lonzarich a few years ago on samarium hexaboride, an insulator that exhibits metal-like behaviour when exposed to strong magnetic fields [6]. She says that without his advice she would probably have left the field. “He is not just teaching you ‘this is how you do physics’ but ‘this is how to survive in the world of physics’,” she says. Lonzarich is modest about how much he contributed to the success of those he has mentored, saying that they taught him at least as much as the other way around.

    One thing he always has for people is time, says Rowley. It helps that he is adept at escaping unnecessary bureaucracy, adds Pines. “He has many different offices so he can always hide at one.” But Lonzarich’s freedom to think is largely enabled by his wife, Gerie. She ensures that grant applications are handed in on time and that flights are caught. Gil says his wife is like the Sun: “So big and important that sometimes you forget it’s the reason everything is there.”

    Lingering mystery

    In the past few years, Lonzarich’s ideas about the intimate link between superconductivity and magnetism have gained new relevance. Physicists explain conventional superconductivity using BCS theory [7], named after the initials of the surnames of the three people who published it in 1957. The theory states that an electron speeding through some materials creates a positively charged distortion in the atomic lattice behind it. This pulls in a second electron, which follows the first like a cyclist riding in a competitor’s slipstream. If enough of these relatively stable ‘Cooper pairs’ form, they create an ordered state in which the two electrons keep one another on course and flow without resistance.

    But this explanation cannot account for sandwiches of copper-based insulators known as cuprates and for iron-based semiconductors. These two classes of superconductor can carry currents without resistance at temperatures up to 133 kelvin. If such transitions can be boosted to room temperature, around 300 kelvin, those superconductors could allow for cheaper energy, medical imaging and transportation. But debate about how they work has raged for 30 years.

    From the start, one camp thought that magnetic interaction — which can be more resilient to temperature than are interactions caused by distortions in the lattice — might somehow bind electrons together to create superconductivity in cuprates. Lonzarich theorized that this magnetic glue might stem from the same quantum fluctuations that ramp up around antiferromagnet quantum critical points. This idea is now hotly debated, and gained some supporting evidence last year in experiments conducted by Taillefer’s team, with collaborators at the National Laboratory for Intense Magnetic Fields in Toulouse, France. The group found that stripping a cuprate of its superconductivity with a powerful magnetic field and adding increasing levels of impurities revealed a sharp phase transition — an otherwise hidden quantum critical point [8]. Although the precise nature of that point is still not clear, it seems likely that antiferromagnetic correlations are at play, says Taillefer. “Which would mean Gil had a hell of an intuition,” he says.

    Lonzarich is now looking beyond conventional high-temperature superconductors. With Rowley and other colleagues, he is examining the nature of ferroelectrics, a little-studied class of ionic materials that generate their own electric field. At low temperature, ferroelectrics can become superconductors in a manner that parallels how superconductivity emerges in magnetic materials. Lonzarich has a hunch that in ferroelectric materials that also exhibit magnetism, electron pairs bind so strongly that the state could survive to room temperature.

    The Universe is richer than most scientists give it credit for, Lonzarich says. Each newly discovered state of matter emerges only when conditions are right and a material is sufficiently pure. Lonzarich speculates that probing the boundaries around those states could reveal more phases, and studying the boundaries of those could reveal yet more, with discoveries unfolding in a fractal manner. “What if each quantum critical point is just the beginning of another generation? There’s some indication we’re heading in that direction,” he says.

    The idea is highly speculative, but Taillefer says people would be wise to listen. The notion that a now-familiar principle could hide deep, complex behaviour “is typical Gil”, he says. “I would definitely put my money on him.”

    See the full article for references.

    See the full article here .

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

  • richardmitnick 1:26 pm on August 26, 2017 Permalink | Reply
    Tags: , , , , , , NATURE, , Rumours swell over new kind of gravitational-wave sighting,   

    From Nature: “Rumours swell over new kind of gravitational-wave sighting” 

    Nature Mag

    24 August 2017
    Davide Castelvecchi

    Gossip over potential detection of colliding neutron stars has astronomers in a tizzy.

    The galaxy NGC 4993 (fuzzy bright spot) in the constellation Hydra, where detectors are rumoured to have spotted gravitational waves from a neutron star merger. Digitized Sky Survey

    Astrophysicists may have detected gravitational waves last week from the collision of two neutron stars in a distant galaxy — and telescopes trained on the same region might also have spotted the event.

    Rumours to that effect are spreading fast online, much to researchers’ excitement. Such a detection could mark a new era of astronomy: one in which phenomena are both seen by conventional telescopes and ‘heard’ as vibrations in the fabric of space-time. “It would be an incredible advance in our understanding,” says Stuart Shapiro, an astrophysicist at the University of Illinois at Urbana–Champaign.

    Scientists who work with gravitational-wave detectors won’t comment on the gossip because the data is still under analysis. Public records show that telescopes around the world have been looking at the same galaxy since last week, but astronomers caution that they could have been picking up signals from an unrelated source.

    As researchers hunt for signals in their data, Nature explains what is known so far, and the possible implications of any discovery.

    What is the gossip?

    The Laser Interferometer Gravitational-Wave Observatory (LIGO) in Louisiana and Washington state has three times detected gravitational waves — ripples in the fabric of space-time — emerging from colliding black holes.

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    But scientists have been hoping to detect ripples from another cosmic cataclysm, such as the merger of neutron stars, remnants of large stars that exploded but were not massive enough to collapse into a black hole. Such an event should also emit radiation across the electromagnetic spectrum — from radio waves to γ-rays — which telescopes might be able to pick up.

    On 18 August, astronomer J. Craig Wheeler of the University of Texas at Austin began the public rumour mill when he tweeted, “New LIGO. Source with optical counterpart. Blow your sox off!” An hour later, astronomer Peter Yoachim of the University of Washington in Seattle tweeted that LIGO had seen a signal with an optical counterpart (that is, something that telescopes could see) from a galaxy called NGC 4993, which is around 40 million parsecs (130 million light years) away in the southern constellation Hydra. “Merging neutron-neutron star is the initial call”, he followed up. Some astronomers who do not want to be identified say that rumours had been privately circulating before Wheeler’s and Yoachim’s tweets.

    If gravitational-wave researchers saw a signal, it is plausible that they could know very quickly whether it emerged from colliding black holes or neutron stars, because each type of event has its own signature, even though data must be studied carefully to be more precise about an event’s origin.

    It’s also possible that LIGO’s sister observatory Virgo in Pisa, Italy, which has been helping LIGO to hunt for gravitational waves since August, after taking a break for an upgrade, might have spotted the event.

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    That would give researchers more confidence about its source. (Virgo has an average sensitivity for neutron-star mergers of only 25 million to 27 million parsecs, but in some regions of the sky, it can see farther, up to 60 million parsecs away, says physicist Giovanni Losurdo, who led the detector’s upgrade work.)

    Both Wheeler and Yoachim declined to comment, and Wheeler later apologized on Twitter. “Right or wrong, I should not have sent that tweet. LIGO deserves to announce when they deem appropriate. Mea culpa,” he wrote.

    What about the telescope observations?

    Public records show that NASA’s Fermi Gamma-ray Space Telescope has spotted γ-rays emerging from the same region of sky as the potential gravitational-wave source.

    NASA/Fermi Telescope

    A senior Fermi member declined to comment on the observation, but it would be consistent with expectations that neutron-star collisions may be behind the enigmatic phenomena known as short γ-ray bursts (GRBs), which typically last a couple of seconds and are usually followed by an afterglow of visible light and sometimes, radio waves and x-rays, lasting up to a few days.

    But although the Fermi telescope has seen a GRB, it may not be able to pinpoint its origin with high precision, astronomers caution.

    A simulation of the merger of a binary neutron star: magnetic field lines are in white. Simulations by M. Ruiz, R. N. Lang, V. Paschalidis and S. L.Shapiro at the University of Illinois at Urbana-Champaign, with visualization assistance from the Illinois Relativity REU team.

    Other telescopes were also turned to look at NGC 4993 after an alert about a potential gravitational wave sighting. On 22 August, a Twitter feed called Space Telescope Live, which provides live updates of what the Hubble Space Telescope is looking at, suggested that a team of astronomers was looking at a binary neutron-star merger using the probe’s on-board spectrograph, which is what astronomers would normally use to look at the afterglow of a short GRB. The Hubble tweet has since been deleted. Public records also confirm that multiple teams have used the Hubble Space Telescope over the last week to examine NGC 4993, and state as their reason that they are trying to follow up on a candidate observation of gravitational waves.

    On 23 August, a commenter on the blog of astrophysicist Peter Coles, of Cardiff University in the UK, noted that NASA’s Chandra X-ray observatory had jumped into the action, too.

    The Chandra website contains a public record of an observation made on 19 August.

    NASA/Chandra Telescope

    The telescope pointed at celestial coordinates in the galaxy NGC 4993 and observed an event called SGRB170817A — indicating ‘short GRB of 2017-August-17’. The most revealing part of the report is the “trigger criteria” section, which explains the reason for over-riding any previously scheduled observation to turn the telescope in that direction. It says: “Gravitational wave source detected by aLIGO, VIRGO, or both.”

    Publicly available records from other major astronomy facilities — including the European Southern Observatory’s Very Large Telescope and the world’s premiere radio observatory, the Atacama Large Millimeter/submillimeter Array (ALMA), both in Chile — show that those also targeted NGC 4993 on 18 and 19 August.

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

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

    What could we learn from a neutron-star merger?

    Gravitational-wave signals from black-hole mergers are brief, typically lasting a second or less. But a neutron-star merger could yield a signal that lasts up to a minute: neutron stars are less massive than black holes and emit less-powerful gravitational waves, so it takes longer for their orbits to decay and for the stars to spiral into each other. Longer events enable much more precise tests of Albert Einstein’s general theory of relativity, which predicts gravitational waves — perhaps giving more clues to the origins of neutron stars.

    The short GRB that telescopes might have observed would be significant, too — not least because if it is associated with gravitational waves, it would validate decades of astrophysical theorizing that GRBs are associated with neutron-star collisions. “Only gravitational waves could give us the smoking gun,” says Eleonora Troja, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

    Still, a short GRB would be an important discovery on its own. Most such events are seen in the distant Universe, billions of parsecs away. NGC 4993, at 40 million parsecs away, would probably be the closest short GRB ever detected, says astrophysicist Derek Fox of Pennsylvania State University in University Park.

    Details of the gravitational waves at the time of the collision and in the following instances could also reveal information about the structure of neutron stars — which is largely unknown — and whether their merger resulted again in a neutron star or in the formation of a new black hole.

    When will we know?

    On 25 August, LIGO and Virgo will end their current data-collecting run. After that, researchers will post only a “top-level update”, meaning a brief note indicating whether the observatories have picked up potential ‘candidate events’ that need further analysis, says David Shoemaker, a physicist at the Massachusetts Institute of Technology who is LIGO’s spokesperson.

    “It will take time to do justice to the data, and ensure that we publish things in which we have very high confidence,” he says.

    Update 25 August: The LIGO–Virgo collaboration posted its top-level update, saying: “Some promising gravitational-wave candidates have been identified in data from both LIGO and Virgo during our preliminary analysis, and we have shared what we currently know with astronomical observing partners. We are working hard to assure that the candidates are valid gravitational-wave events, and it will require time to establish the level of confidence needed to bring any results to the scientific community and the greater public. We will let you know as soon we have information ready to share.”

    See the full article here .

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    • Jose 5:40 am on October 29, 2017 Permalink | Reply

      The detection of the gravitational waves produced by the merger of two neutron stars –GW170817– has allowed scientists to fix at 70 km/s per megaparsec * the value of the increase in speed of the expansion of the universe in the 130 million light years that separate us from the origin of said merger.
      As these calculations approach the speed of light throughout the age of the universe, we can do the inverse calculation to determine the average increase in the velocity of expansion so that the observable universe is of the age stated by the Big Bang Theory.
      The result is 300.000 km/s /(13.799/3,26) Mpc =70,820 km/s Mpc. https://molwick.com/en/gravitation/072-gravitational-waves.html#big-bang


    • richardmitnick 7:09 am on October 29, 2017 Permalink | Reply

      Thanks for visiting sciencesprings. I went to your site. Beautiful and instructive.


    • Jose 12:34 pm on October 29, 2017 Permalink | Reply

      Thank you too. My pleasure!


  • richardmitnick 5:36 pm on July 11, 2017 Permalink | Reply
    Tags: , , Female astronomers of colour face daunting discrimination, NATURE, Not in this article but so do caucasion women esp in Physics and Astronomy   

    From Nature: “Female astronomers of colour face daunting discrimination” 

    Nature Mag

    11 July 2017
    Rachael Lallensack

    Two-fifths report feeling unsafe at work, and 21% have concerns about attending conferences.

    Women of colour working in astronomy and planetary science experience high rates of harassment at work, a study finds. In a survey, a striking 40% of these scientists reported feeling unsafe in their workplaces owing to their gender, and 28% reported feeling unsafe on account of their race.

    The findings, published on 10 July in the Journal of Geophysical Research: Planets [1], illustrate a well-researched phenomenon: a woman’s risk of being subjected to gendered or race-based harassment is higher if she belongs to multiple minority groups. Women of colour were more likely than white women or men of colour to recall a negative workplace experience during a five-year period from 2011-2015. Such incidents included having their mental or physical ability questioned.

    “This is something that I’ve known about, that I’ve seen and experienced, as someone of colour, for as long as I’ve been in the field. So I’m not surprised,” says Cristina Thomas, an astronomer at the Planetary Science Institute who is based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “I was very happy to see someone quantify what was happening so other people would see it.”

    The study, whose participants ranged from undergraduate students to senior researchers, suggests that the negative environment experienced by many female scientists of colour is often apparent to colleagues of other genders or ethnicities.

    Eighty-eight per cent of the 474 participants — a group that was 84% white and included both men and women — had heard remarks that were racist, sexist or directed at a person’s gender or intelligence in their current workplace.

    Survey respondents included 45 women of colour, who collectively accounted for 11% of participants. That proportion is double the percentage of minority women in the United States who hold bachelor’s degrees in physical science. [That is a sad statistic. In The U.S. we suck at acknowledging talent and we just lose it.]

    The analysis is the first of its kind in the astronomy and planetary-science fields, and one of few in a science, technology, engineering or medicine discipline that specifically examines the experiences of women of colour, says study co-author Christina Richey, former chair of the American Astronomical Society’s Committee on the Status of Women in Astronomy in Washington DC. The research team was made up of two planetary scientists and two social scientists, including anthropologist Kathryn Clancy of the University of Illinois at Urbana-Champaign, who led a high-profile survey of harassment in scientific fieldwork that was published in 2014 in PLoS ONE [2]

    The latest study found that harassment and discrimination can have a heavy impact on an individual’s career decisions. Twenty-one per cent of men of colour, 18% of women of colour and 12% of white women reported avoiding a class, conference or professional event because they did not feel safe attending. [Think of the talent lost.] Such events can help to foster professional networks, mentorship and opportunities for collaboration — connections that can advance a scientist’s career, says Zuleyka Zevallos, a sociologist at Swinburne University of Technology in Melbourne, Australia.

    Systemic solutions

    “If a culture of hostility remains in place, it doesn’t matter what we do at the individual level because the system is broken. The pipeline is broken,” says Zevallos, who helped to implement gender-education programmes at universities in her former position at the Australian Academy of Science in Canberra.

    The analysis has sparked intense discussion online among astronomers and planetary scientists. Several female scientists of colour have shared their stories on Twitter, describing the significant, but sometimes subtle, consequences of harassment and discrimination in their own lives.

    Chanda Prescod-Weinstein, a theoretical physicist at the University of Washington in Seattle, tweeted that when faced with events that she thought might expose her to harassment, discrimination or other negative experiences, she sometimes brought her husband along. But that created an extra financial burden for the couple.

    In recent years, professional societies such as the American Astronomical Society and American Geophysical Union have taken steps to prevent harassment at their meetings. The latest study suggests several actions that research institutions, funding agencies and scientific societies can take to reduce harassment. These include updating their codes of conduct to bar harassment; instituting mandatory cultural-awareness training; encouraging leading researchers to model appropriate behaviour; and putting in place swift sanctions for perpetrators.

    “It’s time to pivot away from the conversation of, ‘Is gender equity and racism a problem in science?’, and shift to taking action,” Zevallos says. “We can’t afford to lose more women of colour, white women and under-represented minorities.”

    [Think about it: if a back Jewish female lesbian magician pulled a rabbit out of a hat, no one would give a rat’s ass about her race, religion or sexual preference. She just pulled a rabbit out of a hat.]

    See the full article here .

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  • richardmitnick 10:12 am on July 5, 2017 Permalink | Reply
    Tags: , “...Full and continued engagement” with the United Kingdom in FP9 would be “an obvious win-win for the UK and the EU”, , , Europe’s next big science-funding programme urged to double its budget, FP9-Framework Programme Nine, , Less bureaucracy, NATURE, One-fifth of the number of fast-growing start-up firms that the United States does, Pascal Lamy, Science Europe, The region trails South Korea on business-research spending, Uncertainty over Brexit negotiations   

    From Nature: “Europe’s next big science-funding programme urged to double its budget” 

    Nature Mag

    04 July 2017
    Alison Abbott

    Pascal Lamy. Julien Warnand/EPA.

    Midway through the European Union’s sprawling 7-year, €75-billion (US$85-billion) research-funding programme known as Horizon 2020 (H2020), scientists are already angling for more money and less red tape in its successor.

    So researchers are delighted with an influential 3 July report that urges the EU to double the budget of its next funding scheme, called Framework Programme Nine (FP9), which is due to launch in 2021. The report says that FP9’s structure should be largely similar to that of H2020, but with less bureaucracy, and suggests that it includes a few major ‘moonshot’ missions in areas such as energy and information technology.

    “Scientists are generally happy with the report because it mostly confirms our thinking,” says Stephan Kuster, the acting director of Science Europe, a Brussels-based organization that represents member-state research agencies. But it lacks details on some of its aims, he says: in particular, how to persuade politicians to approve such a large budget hike.

    The report comes from a group of academic and industry experts invited by the European Commission to formulate a vision for future research plans, headed by a former director-general of the World Trade Organization, Pascal Lamy. Commission insiders say its ideas will strongly influence the shape of FP9 — set to be the first major EU funding programme to take place after the United Kingdom leaves the union in 2019.

    Uncertainty over Brexit negotiations means that the commission isn’t close to determining its total post-2020 budget, and it will not propose what FP9 might look like until the end of this year. That has not stopped advocates asking for more cash: in June, a research committee for the European Parliament proposed a €120-billion budget for FP9, assuming that, like H2020, it will run for 7 years.

    In an interview with the European Commission alongside his report, Lamy calls that “a bare minimum”. His team’s report says that whatever the result of Brexit negotiations, “full and continued engagement” with the United Kingdom in FP9 would be “an obvious win-win for the UK and the EU”. The programme should also be opened up more widely to non-EU countries, the report says.

    Falling success rates

    European scientists have a love–hate relationship with the EU’s massive research programmes. Researchers appreciate the funding and the support of collaborative projects, but deplore the bureaucracy and the way each new programme changes the rules. An interim evaluation of H2020, published in May, suggests it has been more popular than its predecessors, in part because of cuts to red tape.

    Still, the evaluation noted that H2020 is heavily oversubscribed, with barely 1 in 9 applications funded — well down on its predecessor programme, which funded nearly 1 in 5. FP9 should return to earlier levels, the Lamy report says.

    Success rates are even lower, below 1 in 10, at the prestigious European Research Council (ERC), which as part of H2020 was given a €13.1-billion budget to fund basic research for 2014–20. The ERC is supposed to reward excellence, but in some of its grant programmes, half of the projects deemed “excellent” by reviewers have gone unfunded. “We would need to double our budget to make sense of our mission,” says ERC president Jean-Pierre Bourguignon.

    The Lamy report recommends keeping H2020’s broad divisions into grants for excellent science, for industrial-innovation projects, and for multinational collaborations that meet societal grand challenges. It suggests that rules of participation be made simpler — with documentation and reporting obligations kept to a minimum, and audits restricted to cases where fraud is suspected. And it proposes that FP9 adopt broader measures of the ‘impact’ of work — going beyond scientific impact to capture effects on policymaking and industrial competitiveness, for instance.

    The EU has an ‘innovation gap’ compared with its trading partners, the report says, noting that the region trails South Korea on business-research spending, and has one-fifth of the number of fast-growing start-up firms that the United States does.

    The report also argues that FP9 should do more to involve Europe’s citizens, including involving them in choosing ‘moonshot’ missions in areas of societal importance, such as climate change, that set targets to be achieved within precise time frames. (As an example, it suggests producing carbon-free steel by 2030.)

    In general, scientists should get better at communicating their work using stories that citizens can understand, the report says: “Communicating on science should become part of researchers’ career and their reward system.”

    See the full article here .

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  • richardmitnick 1:15 pm on June 25, 2017 Permalink | Reply
    Tags: , , Bacteriophages, , Genetically modified viruses, NATURE   

    From Nature: “Modified viruses deliver death to antibiotic-resistant bacteria” 

    Nature Mag

    21 June 2017
    Sara Reardon

    Engineered microbes turn a bacterium’s immune response against itself using CRISPR.

    Phages (green) attack a bacterium (orange). Researchers are hoping to use engineered versions of these viruses to fight antibiotic resistance. AMI Images/SPL

    Genetically modified viruses that cause bacteria to kill themselves could be the next step in combating antibiotic-resistant infections [Nature].

    Several companies have engineered such viruses, called bacteriophages, to use the CRISPR gene-editing system to kill specific bacteria, according to a presentation at the CRISPR 2017 conference in Big Sky, Montana, last week. These companies could begin clinical trials of therapies as soon as next year.

    Initial tests have saved mice from antibiotic-resistant infections that would otherwise have killed them, said Rodolphe Barrangou, chief scientific officer of Locus Biosciences in Research Triangle Park, North Carolina, at the conference.

    Bacteriophages isolated and purified from the wild have long been used to treat infections in people, particularly in Eastern Europe. These viruses infect only specific species or strains of bacteria, so they have less of an impact on the human body’s natural microbial community, or microbiome, than antibiotics do. They are also generally thought to be very safe for use in people.

    But the development of phage therapy has been slow, in part because these viruses are naturally occurring and so cannot be patented. Bacteria can also quickly evolve resistance to natural phages, meaning researchers would have to constantly isolate new ones capable of defeating the same bacterial strain or species. And it would be difficult for regulatory agencies to continually approve each new treatment.

    CRISPR-fuelled death

    To avoid these issues, Locus and several other companies are developing phages that turn the bacterial immune system known as CRISPR against itself. In Locus’ phages, which target bacteria resistant to antibiotics, the CRISPR system includes DNA with instructions for modified guide RNAs that home in on part of an antibiotic-resistance gene. Once the phage infects a bacterium, the guide RNA latches on to the resistance gene. That prompts an enzyme called Cas3, which the bacterium normally produces to kill phages, to destroy that genetic sequence instead. Cas3 eventually destroys all the DNA, killing the bacterium. “I see some irony now in using phages to kill bacteria,” says Barrangou.

    Another company, Eligo Bioscience in Paris, uses a similar approach. It has removed all the genetic instructions that allow phages to replicate, and inserted DNA that encodes guide RNAs and the bacterial enzyme Cas9. Cas9 cuts the bacterium’s DNA at a designated spot, and the break triggers the bacterium to self-destruct. The system will target human gut pathogens, says Eligo chief executive Xavier Duportet, although he declined to specify which ones.

    The two companies hope to start clinical trials in 18–24 months. Their first goal is to treat bacterial infections that cause severe disease. But eventually, they want to develop phages that let them precisely engineer the human microbiome by removing naturally occurring bacteria associated with conditions such as obesity, autism and some cancers.

    Both Barrangou and Duportet acknowledge that for now, causal links between the human microbiome and these conditions are tenuous at best. But they hope that by the time their therapies have been proved safe and effective in humans, the links will be better understood. Phages could also allow researchers to manipulate the microbiomes of experimental animals, which could help them to untangle how certain bacteria influence conditions such as autism, says Timothy Lu, a synthetic biologist at the Massachusetts Institute of Technology in Cambridge and a co-founder of Eligo.

    An engineered solution

    Other companies are working to get phages to perform different tasks. ‘Supercharged’ phages, created by a group at Synthetic Genomics in La Jolla, California, could contain dozens of special features, including enzymes that break down biofilms or proteins that help to hide the phages from the human immune system.

    But engineered phages still have to overcome some hurdles. Treating an infection might require a large volume of phages, says Elizabeth Kutter, a microbiologist at Evergreen State College in Olympia, Washington, and it’s unclear whether this would trigger immune reactions, some of which could interfere with the treatment. Phages could also potentially transfer antibiotic-resistance genes to non-resistant bacteria, she notes.

    Lu adds that bacteria may still develop resistance even to the engineered phages. So researchers might have to frequently modify their phages to keep up with bacterial mutations.

    But as antibiotic resistance spreads, Kutter says, there will be plenty of space for both engineered phages and natural phage therapies, which are also growing in popularity. “I think they’ll complement the things that can be done by natural phages that have been engineered for hundreds of thousands of years,” she says.

    Related stories and links
    See the full article for further references with links

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  • richardmitnick 8:09 pm on June 2, 2017 Permalink | Reply
    Tags: , , , , NATURE   

    From Nature: “Next-generation cancer drugs boost immunotherapy responses” 

    Nature Mag

    02 June 2017
    Heidi Ledford

    Early clinical trial data suggest that combining medicines improves treatment.

    Combining cancer treatments can boost remission rates in patients with kidney cancer. David McCarthy/SPL

    An approach to unleashing immune responses against cancer is showing promise in early clinical trials, and may boost the effectiveness of existing therapies.

    The experimental drugs target a protein called IDO, which starves immune cells by breaking down the crucial amino acid tryptophan. IDO can suppress immune responses and rein in potentially damaging inflammation. But it can also halt the body’s natural immune response to cancer and allow tumours to grow unchecked. Some tumours even express IDO to shield themselves from the immune system.

    Researchers will present the latest round of clinical data from IDO-inhibiting drugs at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago, Illinois, on 2–6 June. The results add to mounting evidence that IDO inhibitors boost the effectiveness of treatments called immunotherapies, which bolster immune responses against cancer. “It’s almost like you’re taking down a tumour force field,” says Michael Postow, a cancer researcher at the Memorial Sloan Kettering Cancer Center in New York City.

    One problem is that tumours express a host of proteins that shut down immune responses, so blocking PD-1 may simply allow another protein to step in. Researchers are frantically searching for ways to boost the success rates of PD-1 inhibitors by combining them with drugs that can block these other proteins. “There are ways around every single one of these checkpoint proteins,” says immunologist Andrew Mellor of Newcastle University, UK. “Therein lies the problem — and therein lies the solution.”

    Greater than the sum of its parts?

    Pharmaceutical companies have been racing to test the effectiveness of combining experimental IDO-inhibiting drugs with approved PD-1 inhibitors. NewLink Genetics in Ames, Iowa, announced in April that combining its IDO-pathway inhibitor indoximod with an anti-PD1 drug shrank tumours in 31 of 60 people with advanced melanoma in the trial.

    And data to be presented at the ASCO meeting suggest that an IDO inhibitor called epacadostat, made by Incyte of Wilmington, Delaware, could boost response rates to anti-PD-1 drugs in lung and kidney cancers. Thirty-five percent of people with non-small-cell lung cancer responded to the combination. In kidney cancer, the combination shrank tumours in 47% of trial participants.

    Other companies are also testing IDO inhibitors — including a firm co-founded by cancer researcher Benoit Van den Eynde of the Ludwig Institute for Cancer Research in Brussels. In 2003, Van den Eynde’s team became the first to demonstrate that IDO is expressed in human tumours1. His company, iTeos Therapeutics in Gosselies, Belgium, has partnered with the pharmaceutical giant Pfizer in New York City, and brought its IDO inhibitor into clinical trials last year.

    It is still early, cautions cancer immunologist Thomas Gajewski of the University of Chicago in Illinois, who has worked on clinical trials of IDO inhibitors. The trials so far have been small and lack a control group that received only PD-1 inhibitors. As a result, researchers can only compare the results of drug combinations with the historical success rates of PD1 inhibitors.

    And there is still a lot to learn about how IDO interacts with the immune system, or what effects an IDO inhibitor could have elsewhere in the body, says Michael Platten, an oncologist at the German Cancer Research Center in Heidelberg. IDO is expressed in many tissues. “This is still a relatively new field,” says Platten. “We do not really understand the molecular mechanism.”

    But an encouraging sign, adds Gajewski, is that so far, the combination of drugs to inhibit IDO and PD-1 seems to be relatively safe, and lacks the toxicity seen when PD-1 inhibitors are used with some other cancer drugs. “In some of the combinations, it looks like there’s benefit beyond anti-PD-1 alone, but without toxicity,” he says. “For me, that’s really an opportunity.”

    See the full article here .

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  • richardmitnick 12:42 pm on May 31, 2017 Permalink | Reply
    Tags: , , , , NATURE, Roque de los Muchachos in La Palma the Canary Islands - the back up site,   

    From Nature: “Canada weighs scientific consequences of moving a mega-telescope’ 

    Nature Mag

    30 May 2017
    Alexandra Witze

    Existing telescopes atop Mauna Kea take advantage of the mountain’s world-class astronomical observing conditions. Babak Tafreshi/NGC

    Is second-best good enough? That’s the question Canadian astronomers will confront this week as they analyze how relocating the planned Thirty Meter Telescope (TMT) could affect their science plans.

    TMT-Thirty Meter Telescope, proposed for Mauna Kea, Hawaii, USA

    A study looking at the consequences of such a move, which researchers will present on 31 May at a meeting of the Canadian Astronomical Society in Edmonton, finds that they’ll still be able to do most of what they want to do — but not everything.

    Legal challenges to the construction of the TMT on the Hawaiian mountain of Mauna Kea meant the international collaboration behind the facility had to consider an alternate site. But less than ideal observing conditions at their back-up site could keep scientists from pursuing what is likely to be one of the hottest topics in astronomy in the coming decade: investigating exoplanet atmospheres.

    The mega-telescope is “a critical component of the Canadian astronomical landscape,” says Michael Balogh, an astronomer at the University of Waterloo in Ontario. The country — one of six major international partners — has committed CAN$243 million (US$180 million) to the project. “If we have to move, it’s effectively a de-scope in the project,” says Balogh.
    A long, hard look

    The back-up site, Roque de los Muchachos in La Palma, the Canary Islands, is lower in elevation than Mauna Kea, and its skies are more turbulent than those above the Hawaii mountain.

    Isaac Newton Group telescopes, at Roque de los Muchachos Observatory on La Palma in the Canary Islands, Spain

    That means that observing conditions are not quite as good; in particular, the extra atmosphere above La Palma interferes with much of the observing in mid-infrared wavelengths of light, the sweet spot for looking at exoplanet atmospheres.

    See the full article here .

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