Tagged: phys.org Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 4:50 pm on July 11, 2017 Permalink | Reply
    Tags: 800 million years is the current frontier in reionization studies, , , , , , , Determining when the first galaxies formed is a challenge, LAEs-Lyman alpha emitting galaxies, phys.org   

    From phys.org: “Distant galaxies ‘lift the veil’ on the end of the cosmic dark ages” 

    physdotorg
    phys.org

    July 11, 2017

    1
    False color image of a 2 square degree region of the LAGER survey field, created from images taken in the optical at 500 nm (blue), in the near-infrared at 920 nm (red), and in a narrow-band filter centered at 964 nm (green). The last is sensitive to hydrogen Lyman alpha emission at z ~ 7. The small white boxes indicate the positions of the 23 LAEs discovered in the survey. The detailed insets (yellow) show two of the brightest LAEs; they are 0.5 arcminutes on a side, and the white circles are 5 arcseconds in diameter. Credit: Zhen-Ya Zheng (SHAO) & Junxian Wang (USTC).

    Astronomers studying the distant Universe have found that small star-forming galaxies were abundant when the Universe was only 800 million years old, a few percent of its present age. The results suggest that the earliest galaxies, which illuminated and ionized the Universe, formed at even earlier times.

    Long ago, about 300,000 years after the beginning of the Universe (the Big Bang), the Universe was dark. There were as yet no stars and galaxies, and the Universe was filled with neutral hydrogen gas. At some point the first galaxies appeared, and their energetic radiation ionized their surroundings, the intergalactic gas, illuminating and transforming the Universe.

    While this dramatic transformation is known to have occurred sometime in the interval between 300 million years and 1 billion years after the Big Bang, determining when the first galaxies formed is a challenge. The intergalactic gas, which is initially neutral, strongly absorbs and scatters the ultraviolet light emitted by the galaxies, making them difficult to detect.

    To home in on when the transformation occurred, astronomers take an indirect approach. Using the demographics of small star-forming galaxies to determine when the intergalactic gas became ionized, they can infer when the ionizing sources, the first galaxies, formed. If star forming galaxies, which glow in the light of the hydrogen Lyman alpha line, are surrounded by neutral hydrogen gas, the Lyman alpha photons are readily scattered, much like headlights in fog, obscuring the galaxies. When the gas is ionized, the fog lifts, and the galaxies are easier to detect.

    A new study [ApJ] taking this approach has discovered 23 candidate Lyman alpha emitting galaxies (LAEs) that were present 800 million years after the Big Bang (at a redshift of z~7), the largest sample detected to date at that epoch. The study, “Lyman-Alpha Galaxies in the Epoch of Reionization” (LAGER), was carried out by an international team of astronomers from China, the US, and Chile using the Dark Energy Camera (DECam) on the CTIO 4-m Blanco telescope.

    Dark Energy Survey

    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam

    2
    Milestones in the history of the Universe (not to scale). The intergalactic gas was in a neutral state from about 300,000 years after the Big Bang until light from the first generation of stars and galaxies began to ionize it. The gas was completely ionized after 1 billion years. The LAGER study takes a close look at the state of the Universe at 800 million years (yellow box) to investigate when and how this transformation occurred. Credit: NAOJ.

    While the study detected many LAEs, it also found that LAEs were 4 times less common at 800 million years than they were a short time later, at 1 billion years (at a redshift of z~5.7). The results imply that the process of ionizing the Universe began early and was still incomplete at 800 million years, with the intergalactic gas about half neutral and half ionized at that epoch. The low incidence rate of LAEs at 800 million years results from the suppression of their Lyman alpha emission by neutral intergalactic gas.

    The study shows that “the fog was already lifting when the universe was 5% of its current age”, explained Sangeeta Malhotra (Goddard Space Flight Center and Arizona State University), one of the co-leads of the survey.

    Junxian Wang (USTC), the organizer of the study, further explained, “Our finding that the intergalactic gas is 50% ionized at z ~ 7 implies that a large fraction of the first galaxies that ionized and illuminated the universe formed early, less than 800 million years after the Big Bang.”

    For Zhenya Zheng (Shanghai Astronomical Observatory, CAS), the lead author of the paper describing these results, “800 million years is the current frontier in reionization studies.” While hundreds of LAEs have been found at later epochs, only about two dozen candidate LAEs were known at 800 million years prior to the current study. The new results dramatically increase the number of LAEs known at this epoch.

    “None of this science would have been possible without the widefield capabilities of DECam and its community pipeline for data reduction,” remarked coauthor James Rhoads. “These capabilities enable efficient surveys and thereby the discovery of faint galaxies as well as rare, bright ones.”

    To build on these results, the team is “continuing the search for distant star forming galaxies over a larger volume of the Universe”, said Leopoldo Infante (Pontificia Catolica University of Chile and the Carnegie Institution for Science), “to study the clustering of LAEs.” Clustering provides unique insights into how the fog lifts. The team is also investigating the nature of these distant galaxies.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 2:48 pm on July 10, 2017 Permalink | Reply
    Tags: , , , How do you build a metal nanoparticle?, phys.org, , U Pittsburgh   

    From U Pittsburgh via phys.org: “How do you build a metal nanoparticle?” 

    University of Pittsburgh

    phys.org

    July 10, 2017

    1
    A structure of a ligand-protected Au25 nanocluster. Credit: Computer-Aided Nano and Energy Lab (C.A.N.E.LA.)

    Although scientists have for decades been able to synthesize nanoparticles in the lab, the process is mostly trial and error, and how the formation actually takes place is obscure. However, a study recently published in Nature Communications by chemical engineers at the University of Pittsburgh’s Swanson School of Engineering explains how metal nanoparticles form.

    Thermodynamic Stability of Ligand-Protected Metal Nanoclusters (DOI: 10.1038/ncomms15988) was co-authored by Giannis Mpourmpakis, assistant professor of chemical and petroleum engineering, and PhD candidate Michael G. Taylor. The research, completed in Mpourmpakis’ Computer-Aided Nano and Energy Lab (C.A.N.E.LA.), is funded through a National Science Foundation CAREER award and bridges previous research focused on designing nanoparticles for catalytic applications.

    “Even though there is extensive research into metal nanoparticle synthesis, there really isn’t a rational explanation why a nanoparticle is formed,” Dr. Mpourmpakis said. “We wanted to investigate not just the catalytic applications of nanoparticles, but to make a step further and understand nanoparticle stability and formation. This new thermodynamic stability theory explains why ligand-protected metal nanoclusters are stabilized at specific sizes.”

    A ligand is a molecule that binds to metal atoms to form metal cores that are stabilized by a shell of ligands, and so understanding how they contribute to nanoparticle stabilization is essential to any process of nanoparticle application. Dr. Mpourmpakis explained that previous theories describing why nanoclusters stabilized at specific sizes were based on empirical electron counting rules – the number of electrons that form a closed shell electronic structure, but show limitations since there have been metal nanoclusters experimentally synthesized that do not necessarily follow these rules.

    “The novelty of our contribution is that we revealed that for experimentally synthesizable nanoclusters there has to be a fine balance between the average bond strength of the nanocluster’s metal core, and the binding strength of the ligands to the metal core,” he said. “We could then relate this to the structural and compositional characteristic of the nanoclusters, like size, number of metal atoms, and number of ligands.

    “Now that we have a more complete understanding of this stability, we can better tailor the nanoparticle morphologies and in turn properties, to applications from biolabeling of individual cells and targeted drug delivery to catalytic reactions, thereby creating more efficient and sustainable production processes.”

    See the full article here. .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The University of Pittsburgh is a state-related research university, founded as the Pittsburgh Academy in 1787. Pitt is a member of the Association of American Universities (AAU), which comprises 62 preeminent doctorate-granting research institutions in North America.

    From research achievements to the quality of its academic programs, the University of Pittsburgh ranks among the best in higher education.

    Faculty members have expanded knowledge in the humanities and sciences, earning such prestigious honors as the National Medal of Science, the MacArthur Foundation’s “genius” grant, the Lasker-DeBakey Clinical Medical Research Award, and election to the National Academy of Sciences and the Institute of Medicine.

    Pitt students have earned Rhodes, Goldwater, Marshall, and Truman Scholarships, among other highly competitive national and international scholarships.

    Alumni have pioneered MRI and TV, won Nobels and Pulitzers, led corporations and universities, served in government and the military, conquered Hollywood and The New York Times bestsellers list, and won Super Bowls and NBA championships.

     
  • richardmitnick 2:58 pm on July 4, 2017 Permalink | Reply
    Tags: , , , , e-MERLIN radio array, NGC 5194 and NGC 5195, phys.org   

    From phys.org: “Shocking case of indigestion in supermassive black hole July 4, 2017” 

    physdotorg
    phys.org

    July 4, 2017
    No writer credit found

    1
    False colour image of NGC 5195 created by combining the VLA 20 cm radio image (red), the Chandra X-ray image (green), and the Hubble Space telescope H-alpha image (blue). The image shows the X-ray and H-alpha arcs, as well as the radio outflows from the supermassive black hole at the centre of NGC 5195. Credit: NRAO / AUI / NSF / NASA / CXC / NASA / ESA / STScI / U. Manchester / Rampadarath et al.

    A multi-wavelength study of a pair of colliding galaxies has revealed the cause of a supermassive black hole’s case of ‘indigestion.’ Results will be presented by Dr Hayden Rampadarath at the National Astronomy Meeting at the University of Hull.

    Once every couple of hundred million years, the small galaxy NGC 5195 falls into the outer arms of its larger companion, NGC 5194, also known as the Whirlpool galaxy. Both galaxies are locked in a gravitational dance that will result – billions of years in the future – in the formation of a single galaxy.

    As NGC 5195 plunges into the Whirlpool, matter streams onto the supermassive black hole at NGC 5195’s centre and forms an accretion disc. The disc grows to a point where the supermassive black hole can no longer accrete or ‘digest’ efficiently and matter is blasted out into the surrounding interstellar medium. Last year, NASA’s Chandra X-Ray observatory spotted arcs of X-ray emission that appeared to result from this ‘force-feeding.’

    NASA/Chandra Telescope

    Now, new high-resolution images of the core of NGC 5195, taken with the e-MERLIN radio array, and archive images of the surrounding area from the Very Large Array (VLA), Chandra and the Hubble Space Telescope, reveal in detail how these blasts occur and spread. The study was led by astronomers at the University of Manchester’s Jodrell Bank Centre for Astrophysics.

    eMerlin Radio Telecope Array, England

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

    NASA/ESA Hubble Telescope

    3
    e-MERLIN maps of the nuclear region of NGC 5195 at 1.4 GHz (left) and 5 GHz (right). The images display a partially resolved source with possible parsec-scale outflows. Credit: e-MERLIN / U. Manchester / Rampadarath et al.

    The supermassive black hole at the centre of NGC 5195 has a mass equivalent to 19 million Suns. When the accretion process breaks down, immense forces and pressures create a shock wave that pushes matter out into the interstellar medium. Electrons, accelerated close to the speed of light, interact with the magnetic field of the interstellar medium and emit energy at radio wavelengths. The shock wave then inflates and heats up the interstellar medium, which emits in the X-ray, and strips the electrons from surrounding neutral hydrogen atoms to make ionised hydrogen gas. This inflated bubble creates the arcs detected by Chandra and Hubble.

    Rampadarath explains: “Comparing the VLA images at radio wavelengths to Chandra’s X-ray observations and the hydrogen-emission detected by Hubble, shows that features are not only connected, but that the radio outflows are in fact the progenitors of the structures seen by Chandra and Hubble. This is an event of galactic proportions that we can see right across the electromagnetic spectrum.”

    He adds: “The age of the arcs in NGC 5195 is 1-2 million years. To put that into context, the first traces of matter were being forced out of the black hole in this system at about the time that our ancestors were learning to make fire. That we are able to observe this event now through such a range of astronomical facilities is quite remarkable.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 4:01 pm on July 1, 2017 Permalink | Reply
    Tags: , phys.org, , , Van der Waals interactions repulsive in confinement   

    From phys.org: “Researchers refute textbook knowledge in molecular interactions” 

    physdotorg
    phys.org

    June 29, 2017

    1
    Repulsive ground state interaction E rep (solid lines) and the sum of repulsion and London attraction (E att) energy (broken lines) for argon and methane dimers on a perfectly reflecting surface. Credit: arXiv:1610.09275 [cond-mat.mes-hall]

    Van der Waals interactions between molecules are among the most important forces in biology, physics, and chemistry, as they determine the properties and physical behavior of many materials. For a long time, it was considered that these interactions between molecules are always attractive. Now, for the first time, Mainak Sadhukhan and Alexandre Tkatchenko from the Physics and Materials Science Research Unit at the University of Luxembourg found that in many rather common situations in nature the van der Waals force between two molecules becomes repulsive. This might lead to a paradigm shift in molecular interactions.

    “The textbooks so far assumed that the forces are solely attractive. For us, the interesting question is whether you can also make them repulsive,” Prof Tkatchenko explains. “Until recently, there was no evidence in scientific literature that van der Waals forces could also be repelling.” Now, the researchers have shown in their paper, published in the renowned scientific journal Physical Review Letters, that the forces are, in fact, repulsive when they take place under confinement.

    The ubiquitous van der Waals force was first explained by the German-American physicist Fritz London in 1930. Using quantum mechanics, he proved the purely attractive nature of the van der Waals force for any two molecules interacting in free space. “However, in nature molecules in most cases interact in confined spaces, such as cells, membranes, nanotubes, etc. In is this particular situation, van der Waals forces become repulsive at large distances between molecules,” says Prof Tkatchenko.

    Mainak Sadhukhan, the co-author of the study, developed a novel quantum-mechanical method that enabled them to model van der Waals forces in confinement. “We could rationalize many previous experimental results that remained unexplained until now. Our new theory allows, for the first time, for an interpretation of many interesting phenomena observed for molecules under confinement,” Mainak Sadhukhan says.

    The discovery could have many potential implications for the delivery of pharmaceutical molecules in cells, water desalination and transport, and self-assembly of molecular layers in photovoltaic devices.

    Prof Tkatchenko’s research group is working on methods that model the properties of a wide range of intermolecular interactions. Only in 2016, they found that the true nature of these van der Wals forces differs from conventional wisdom in chemistry and biology, as they have to be treated as coupling between waves rather than as mutual attraction (or repulsion) between particles.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 7:19 pm on June 26, 2017 Permalink | Reply
    Tags: , , It is a dream come true to follow in such detail how a glassy state of water transforms into a viscous liquid which almost immediately transforms to a different even more viscous liquid of much lower , phys.org, , Stockholm University, The pioneer of X-ray radiation Wolfgang Röntgen himself speculated that water can exist in two different forms, Water exists as two different liquids   

    From phys.org: “Water exists as two different liquids” 

    physdotorg
    phys.org

    June 26, 2017

    1
    Artist’s impression of the two forms of ultra-viscous liquid water with different density. On the background is depicted the x-ray speckle pattern taken from actual data of high-density amorphous ice, which is produced by pressurizing water at very low temperatures. Credit: Mattias Karlén

    We normally consider liquid water as disordered with the molecules rearranging on a short time scale around some average structure. Now, however, scientists at Stockholm University have discovered two phases of the liquid with large differences in structure and density.

    2

    The results are based on experimental studies using X-rays, which are now published in Proceedings of the National Academy of Science (US).

    Most of us know that water is essential for our existence on planet Earth. It is less well-known that water has many strange or anomalous properties and behaves very differently from all other liquids. Some examples are the melting point, the density, the heat capacity, and all-in-all there are more than 70 properties of water that differ from most liquids. These anomalous properties of water are a prerequisite for life as we know it.

    “The new remarkable property is that we find that water can exist as two different liquids at low temperatures where ice crystallization is slow”, says Anders Nilsson, professor in Chemical Physics at Stockholm University. The breakthrough in the understanding of water has been possible through a combination of studies using X-rays at Argonne National Laboratory near Chicago, where the two different structures were evidenced and at the large X-ray laboratory DESY in Hamburg where the dynamics could be investigated and demonstrated that the two phases indeed both were liquid phases. Water can thus exist as two different liquids.


    ANL/APS

    DESY Petra III


    DESY Helmholtz Centres & Networks

    “It is very exciting to be able to use X-rays to determine the relative positions between the molecules at different times”, says Fivos Perakis, postdoc at Stockholm University with a background in ultrafast optical spectroscopy. “We have in particular been able to follow the transformation of the sample at low temperatures between the two phases and demonstrated that there is diffusion as is typical for liquids”.

    When we think of ice it is most often as an ordered, crystalline phase that you get out of the ice box, but the most common form of ice in our planetary system is amorphous, that is disordered, and there are two forms of amorphous ice with low and high density. The two forms can interconvert and there have been speculations that they can be related to low- and high-density forms of liquid water. To experimentally investigate this hypothesis has been a great challenge that the Stockholm group has now overcome.

    “I have studied amorphous ices for a long time with the goal to determine whether they can be considered a glassy state representing a frozen liquid”, says Katrin Amann-Winkel, researcher in Chemical Physics at Stockholm University. “It is a dream come true to follow in such detail how a glassy state of water transforms into a viscous liquid which almost immediately transforms to a different, even more viscous, liquid of much lower density”.

    “The possibility to make new discoveries in water is totally fascinating and a great inspiration for my further studies”, says Daniel Mariedahl, PhD student in Chemical Physics at Stockholm University. “It is particularly exciting that the new information has been provided by X-rays since the pioneer of X-ray radiation, Wolfgang Röntgen, himself speculated that water can exist in two different forms and that the interplay between them could give rise to its strange properties”.

    “The new results give very strong support to a picture where water at room temperature can’t decide in which of the two forms it should be, high or low density, which results in local fluctuations between the two”, says Lars G.M. Pettersson, professor in Theoretical Chemical Physics at Stockholm University. “In a nutshell: Water is not a complicated liquid, but two simple liquids with a complicated relationship.”

    These new results not only create an overall understanding of water at different temperatures and pressures, but also how water is affected by salts and biomolecules important for life. In addition, the increased understanding of water can lead to new insights on how to purify and desalinate water in the future. This will be one of the main challenges to humanity in view of the global climate change.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 1:00 pm on June 17, 2017 Permalink | Reply
    Tags: , , phys.org,   

    From phys.org: “No Universe without Big Bang” 

    physdotorg
    phys.org

    June 15, 2017

    1
    Credit: J.-L. Lehners (Max Planck Institute for Gravitational Physics)

    According to Einstein’s theory of relativity, the curvature of spacetime was infinite at the big bang. In fact, at this point all mathematical tools fail, and the theory breaks down. However, there remained the notion that perhaps the beginning of the universe could be treated in a simpler manner, and that the infinities of the big bang might be avoided. This has indeed been the hope expressed since the 1980s by the well-known cosmologists James Hartle and Stephen Hawking with their “no-boundary proposal”, and by Alexander Vilenkin with his “tunnelling proposal”. Now scientists at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in Potsdam and at the Perimeter Institute in Canada have been able to use better mathematical methods to show that these ideas cannot work.

    One of the principal goals of cosmology is to understand the beginning of our universe. Data from the Planck satellite mission shows that 13.8 billion years ago the universe consisted of a hot and dense soup of particles. Since then the universe has been expanding. This is the main tenet of the hot big bang theory, but the theory fails to describe the very first stages themselves, as the conditions were too extreme. Indeed, as we approach the big bang, the energy density and the curvature grow until we reach the point where they become infinite.

    As an alternative, the “no-boundary” and “tunneling” proposals assume that the tiny early universe arose by quantum tunnelling from nothing, and subsequently grew into the large universe that we see. The curvature of spacetime would have been large, but finite in this beginning stage, and the geometry would have been smooth – without boundary (see Fig. 1, left panel). This initial configuration would replace the standard big bang. However, for a long time the true consequences of this hypothesis remained unclear. Now, with the help of better mathematical methods, Jean-Luc Lehners, group leader at the AEI, and his colleagues Job Feldbrugge and Neil Turok at Perimeter Institute, managed to define the 35 year old theories in a precise manner for the first time, and to calculate their implications [Physical Review D]. The result of these investigations is that these alternatives to the big bang are no true alternatives. As a result of Heisenberg’s uncertainty relation, these models do not only imply that smooth universes can tunnel out of nothing, but also irregular universes. In fact, the more irregular and crumpled they are, the more likely (see Fig. 1, right panel). “Hence the “no-boundary proposal” does not imply a large universe like the one we live in, but rather tiny curved universes that would collapse immediately”, says Jean-Luc Lehners, who leads the “theoretical cosmology” group at the AEI.

    Hence one cannot circumvent the big bang so easily. Lehners and his colleagues are now trying to figure out what mechanism could have kept those large quantum fluctuations in check under the most extreme circumstances, allowing our large universe to unfold.

    The big bang, in its complicated glory, retains all its mystery.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 8:06 am on June 14, 2017 Permalink | Reply
    Tags: , , phys.org, , Water circling drain experiments offer insight into black holes   

    From phys.org: “Water circling drain experiments offer insight into black holes” 

    physdotorg
    phys.org

    June 14, 2017
    Bob Yirka

    1
    This artist’s concept depicts a supermassive black hole at the center of a galaxy. The blue color here represents radiation pouring out from material very close to the black hole. The grayish structure surrounding the black hole, called a torus, is made up of gas and dust. Credit: NASA/JPL-Caltech

    A small international team of researchers has found that water waves created due to scattering from a spinning vortex can show rotational superradiance—an effect astrophysicists have predicted likely to occur in black holes, but which has never been replicated in a lab experiment. In their paper published in the journal Nature Physics, the group explains how they observed and measured waves propagating on the surface of water near a draining vortex and what they found.

    As the researchers explain, when a wave strikes an obstacle, it tends to scatter, as can be observed at virtually any seashore. But more difficult to see is that some of the wave is reflected as well as partially transmitted. This led to a theory back in 1954 by Robert Dicke that suggests if an object is spinning, the waves can be amplified by extracting energy from the parts of the wave that are scattered—a phenomenon called superradiance. In this new effort, the researchers conducted experiments designed to prove the theory correct.

    The experiments consisted of placing water in a 3 x 1.5 meter tank with a 4 cm hole at the center to serve as a drain—the researchers took measurements of wave activity by sensors mounted on the side of the tank (and by a high-speed, three-dimensional air–fluid interface sensor) as pumped-in water was drained, creating a vortex. The researchers report that they observed waves propagating on the surface and that measurements confirmed the waves were amplified after scattering occurred. They further report that the largest amplification recorded was 14 percent +/– 8 percent with waves of 3.70Hz in water that was just 6.25 cm deep. They claim their findings agree with theory, and therefore that their findings can be applied to research surrounding black holes. This is because they believe the scattering of shallow waves on water is analogous to the action that occurs at the event horizon of a black hole. They also note that new, more sensitive gravitational wave detectors might someday be able to measure roughly the same behavior with real black holes.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 8:35 am on June 4, 2017 Permalink | Reply
    Tags: De-sensitising the immune system, Gene therapy could 'turn off' severe allergies, , phys.org, , UQ Diamantina Institute   

    From U Queenland: “Gene therapy could ‘turn off’ severe allergies” 

    Queens U bloc

    Queens University

    MedicalXpress

    June 2, 2017

    1
    Associate Professor Ray Steptoe. Credit: The University of Queensland

    A single treatment giving life-long protection from severe allergies such as asthma could be made possible by immunology research at The University of Queensland.

    A team led by Associate Professor Ray Steptoe at the UQ Diamantina Institute has been able to ‘turn-off’ the immune response which causes allergic reaction in animals.

    “When someone has an allergy or asthma flare-up, the symptoms they experience results from immune cells reacting to protein in the allergen,” Professor Steptoe said.

    “The challenge in asthma and allergies is that these immune cells, known as T-cells, develop a form of immune ‘memory’ and become very resistant to treatments.

    “We have now been able ‘wipe’ the memory of these T-cells in animals with gene therapy, de-sensitising the immune system so that it tolerates the protein.

    “Our work used an experimental asthma allergen, but this research could be applied to treat those who have severe allergies to peanuts, bee venom, shell fish and other substances.”

    Dr Steptoe said the findings would be subject to further pre-clinical investigation, with the next step being to replicate results using human cells in the laboratory.”

    “We take blood stem cells, insert a gene which regulates the allergen protein and we put that into the recipient.

    “Those engineered cells produce new blood cells that express the protein and target specific immune cells, ‘turning off’ the allergic response.”

    Dr Steptoe said the eventual goal would be a single injected gene therapy, replacing short-term treatments that target allergy symptoms with varying degrees of effectiveness.

    “We haven’t quite got it to the point where it’s as simple as getting a flu jab, so we are working on making it simpler and safer so it could be used across a wide cross-section of affected individuals,” Dr Steptoe said.

    “At the moment, the target population might be those individuals who have severe asthma or potentially lethal food allergies.”

    Dr Steptoe’s research has been funded by the Asthma Foundation and the National Health and Medical Research Council.

    Asthma Foundation of Queensland and New South Wales Chief Executive Officer Dr Peter Anderson said more than two million Australians have asthma, and current statistics show that more than half of those are regularly burdened with symptoms of the disease.

    “Even though there are effective treatments available for the vast majority, patients face a number of obstacles and challenges in their self-management practices,” Dr Anderson said.

    “The Foundation welcomes the findings of this research and looks forward to a day in the future when a safe one-off treatment may be available that has the potential to eliminate any experience of asthma in vulnerable patients.”

    The research is published in JCI Insight.

    See the full article here .

    Please help promote STEM in your local schools .

    STEM Icon

    Stem Education Coalition

    Queens U Campus

    Queen’s University is a community, 170+ years of tradition, academic excellence, research, and beautiful waterfront campus made of limestone buildings and modern facilities. But more than anything Queen’s is people.

    We are researchers, scholars, artists, professors and students with an ambitious spirit who want to develop ideas that can make a difference in the world. People who imagine together what the future could be and work together to realize it.

    Queen’s is one of Canada’s oldest degree-granting institutions, and has influenced Canadian higher education since 1841 when it was established by Royal Charter of Queen Victoria.

    Located in Kingston, Ontario, Canada, it is a mid-sized university with several faculties, colleges and professional schools, as well as the Bader International Study Centre located in Herstmonceux, East Sussex, United Kingdom.

    Queen’s balances excellence in undergraduate studies with well-established and innovative graduate programs, all within a dynamic learning environment.

     
  • richardmitnick 3:22 pm on June 2, 2017 Permalink | Reply
    Tags: Blow-out craters, CAGE Centre for Arctic Gas Hydrate Environment and Climate, , Massive craters formed by methane blow-outs from the Arctic sea floor, phys.org, Seeping methane and other gases, Unbearable pressure builds up   

    From phys.org: ” Massive craters formed by methane blow-outs from the Arctic sea floor” 

    physdotorg
    phys.org

    June 1, 2017
    No writer credit

    1
    The massive craters were formed around 12,000 years ago, but are still seeping methane and other gases. Credit: Andreia Plaza Faverola/CAGE

    A new study in Science shows that hundreds of massive, kilometer-wide craters on the ocean floor in the Arctic were formed by substantial methane expulsions.

    Even though the craters were formed some 12,000 years ago, methane is still leaking profusely from the craters. Methane is a potent greenhouse gas, and of major concern in our warming climate.

    “The crater area was covered by a thick ice sheet during the last ice age, much as West Antarctica is today. As climate warmed, and the ice sheet collapsed, enormous amounts of methane were abruptly released. This created massive craters that are still actively seeping methane ” says Karin Andreassen, first author of the study and professor at CAGE Centre for Arctic Gas Hydrate, Environment and Climate.

    Today more than 600 gas flares are identified in and around these craters, releasing the greenhouse gas steadily into the water column.

    “But that is nothing compared to the blow-outs of the greenhouse gas that followed the deglaciation. The amounts of methane that were released must have been quite impressive.”

    Siberian craters small in comparison

    A few of these craters were first observed in the 90-ties. But new technology shows that the craters cover a much larger area than previously thought and provides more detailed imaging for interpretation

    “We have focused on craters that are 300 meters to 1 kilometre wide, and have mapped approximately 100 craters of this size in the area. But there are also many hundred smaller ones, less than 300 meters wide that is” says Andreassen.

    2
    Several hundred of craters in the area. Over one hundred of them are up to one kilometer wide. Credit: K. Andreassen/CAGE

    In comparison, the huge blow-out craters on land on the Siberian peninsulas Yamal and Gydan are 50-90 meters wide, but similar processes may have been involved in their formation.

    The Arctic ocean floor hosts vast amounts of methane trapped as hydrates, which are ice-like, solid mixtures of gas and water.These hydrates are stable under high pressure and cold temperatures. The ice sheet provides perfect conditions for subglacial gas hydrate formation, in the past as well as today.

    Unbearable pressure builds up

    Some 2000 metres of ice loaded what now is ocean floor with heavy weight. Under the ice, methane gas from deeper hydrocarbon reservoirs moved upward, but could not escape. It was stored as gas hydrate in the sediment, constantly fed by gas from below, creating over-pressured conditions.

    3
    The study area is in Bjørnøyrenna close to the Arctic archipelago Svalbard. Credit: K. Andreassen/CAGE

    “As the ice sheet rapidly retreated, the hydrates concentrated in mounds, and eventually started to melt, expand and cause over-pressure. The principle is the same as in a pressure cooker: if you do not control the release of the pressure, it will continue to build up until there is a disaster in your kitchen. These mounds were over-pressured for thousands of years, and then the lid came off. They just collapsed releasing methane into the water column” says Andreassen.

    Similar processes are ongoing under ice sheets today

    Major methane venting events such as this appear to be rare, and may therefore easily be overlooked.

    “Despite their infrequency, the impact of such blow-outs may still be greater than impact from slow and gradual seepage. It remains to be seen whether such abrupt and massive methane release could have reached the atmosphere. We do estimate that an area of hydrocarbon reserves twice the size of Russia was directly influenced by ice sheets during past glaciation. This means that a much larger area may have had similar abrupt gas releases in the overlapping time period ” says Andreassen

    Another fact to consider is that there are reserves of hydrocarbons beneath the load of West Antarctica and Greenland ice sheets today.

    “Our study provides the scientific community with a good past analogue for what may happen to future methane releases in front of contemporary, retreating ice sheets” concludes Andreassen.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 1:54 pm on May 30, 2017 Permalink | Reply
    Tags: , , New antibiotic packs a punch against bacterial resistance, phys.org,   

    From Scripps via phys.org: “New antibiotic packs a punch against bacterial resistance” 

    Scripps
    Scripps Research Institute

    phys.org

    May 29, 2017
    No writer credit found

    1
    A colorized scanning electron micrograph of MRSA. Credit: National Institute of Allergy and Infectious Diseases

    Scientists at The Scripps Research Institute (TSRI) have given new superpowers to a lifesaving antibiotic called vancomycin, an advance that could eliminate the threat of antibiotic-resistant infections for years to come. The researchers, led by Dale Boger, co-chair of TSRI’s Department of Chemistry, discovered a way to structurally modify vancomycin to make an already-powerful version of the antibiotic even more potent.

    “Doctors could use this modified form of vancomycin without fear of resistance emerging,” said Boger, whose team announced the finding today in the journal Proceedings of the National Academy of Sciences.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Scripps Research Institute (TSRI), one of the world’s largest, private, non-profit research organizations, stands at the forefront of basic biomedical science, a vital segment of medical research that seeks to comprehend the most fundamental processes of life. Over the last decades, the institute has established a lengthy track record of major contributions to the betterment of health and the human condition.

    The institute — which is located on campuses in La Jolla, California, and Jupiter, Florida — has become internationally recognized for its research into immunology, molecular and cellular biology, chemistry, neurosciences, autoimmune diseases, cardiovascular diseases, virology, and synthetic vaccine development. Particularly significant is the institute’s study of the basic structure and design of biological molecules; in this arena TSRI is among a handful of the world’s leading centers.

    The institute’s educational programs are also first rate. TSRI’s Graduate Program is consistently ranked among the best in the nation in its fields of biology and chemistry.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: