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  • richardmitnick 9:47 am on April 24, 2017 Permalink | Reply
    Tags: Columbia U, Lithium batteries,   

    From Columbia via phys.org: “Freezing lithium batteries may make them safer and bendable” 

    Columbia U bloc

    Columbia University

    phys.org

    [THIS IS IMPORTANT AS WE SEE GREATER USE OF LITHIUM BATTERIES]

    April 24, 2017

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    Schematic of vertically aligned and connected ceramic channels for enhancing ionic conduction. In the left figure, ceramic particles are randomly dispersed in the polymer matrix, where ion transport is blocked by the polymer matrix with a low conductivity. In the right one, vertically aligned and connected structure facilitates ion transport, which can be realized by the ice-templating method. Credit: Yuan Yang/Columbia Engineering.

    Yuan Yang, assistant professor of materials science and engineering at Columbia Engineering, has developed a new method that could lead to lithium batteries that are safer, have longer battery life, and are bendable, providing new possibilities such as flexible smartphones. His new technique uses ice-templating to control the structure of the solid electrolyte for lithium batteries that are used in portable electronics, electric vehicles, and grid-level energy storage. The study is published online April 24 in Nano Letters.

    Liquid electrolyte is currently used in commercial lithium batteries, and, as everyone is now aware, it is highly flammable, causing safety issues with some laptops and other electronic devices. Yang’s team explored the idea of using solid electrolyte as a substitute for the liquid electrolyte to make all-solid-state lithium batteries. They were interested in using ice-templating to fabricate vertically aligned structures of ceramic solid electrolytes, which provide fast lithium ion pathways and are highly conductive. They cooled the aqueous solution with ceramic particles from the bottom and then let ice grow and push away and concentrate the ceramic particles. They then applied a vacuum to transition the solid ice to a gas, leaving a vertically aligned structure. Finally, they combined this ceramic structure with polymer to provide mechanical support and flexibility to the electrolyte.

    “In portable electronic devices, as well as electric vehicles, flexible all-solid-state lithium batteries not only solve the safety issues, but they may also increase battery energy density for transportation and storage. And they show great promise in creating bendable devices,” says Yang, whose research group is focused on electrochemical energy storage and conversion and thermal energy management.

    Researchers in earlier studies used either randomly dispersed ceramic particles in polymer electrolyte or fiber-like ceramic electrolytes that are not vertically aligned. “We thought that if we combined the vertically aligned structure of the ceramic electrolyte with the polymer electrolyte, we would be able to provide a fast highway for lithium ions and thus enhance the conductivity,” says Haowei Zhai, Yang’s PhD student and the paper’s lead author. “We believe this is the first time anyone has used the ice-templating method to make flexible solid electrolyte, which is nonflammable and nontoxic, in lithium batteries. This opens a new approach to optimize ion conduction for next-generation rechargeable batteries.”

    In addition, the researchers say, this technique could in principle improve the energy density of batteries: By using the solid electrolyte, the lithium battery’s negative electrode, currently a graphite layer, could be replaced by lithium metal, and this could improve the battery’s specific energy by 60% to 70%. Yang and Zhai plan next to work on optimizing the qualities of the combined electrolyte and assembling the flexible solid electrolyte together with battery electrodes to construct a prototype of a full lithium battery.

    “This is a clever idea,” says Hailiang Wang, assistant professor of chemistry at Yale University. “The rationally designed structure really helps enhance the performance of composite electrolyte. I think that this is a promising approach.”

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    See the full article here .

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    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

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  • richardmitnick 2:09 pm on March 13, 2017 Permalink | Reply
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    From Columbia: “New Study Finds Radiation from Nearby Galaxies Helped Fuel First Monster Black Holes” 

    Columbia U bloc

    Columbia University

    March 13, 2017
    Kim Martineau

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    The massive black hole shown at left in this drawing is able to rapidly grow as intense radiation from a galaxy nearby shuts down star-formation in its host galaxy. Illustration Courtesy of John Wise, Georgia Tech

    The appearance of supermassive black holes at the dawn of the universe has puzzled astronomers since their discovery more than a decade ago. A supermassive black hole is thought to form over billions of years, but more than two dozen of these behemoths have been sighted within 800 million years of the Big Bang 13.8 billion years ago.

    In a new study in the journal Nature Astronomy, a team of researchers from Dublin City University, Columbia University, Georgia Tech, and the University of Helsinki, add evidence to one theory of how these ancient black holes, about a billion times heavier than our sun, may have formed and quickly put on weight.

    In computer simulations, the researchers show that a black hole can rapidly grow at the center of its host galaxy if a nearby galaxy emits enough radiation to switch off its capacity to form stars. Thus disabled, the host galaxy grows until its eventual collapse, forming a black hole that feeds on the remaining gas, and later, dust, dying stars, and possibly other black holes, to become super gigantic.

    “The collapse of the galaxy and the formation of a million-solar-mass black hole takes 100,000 years — a blip in cosmic time,” says study co-author Zoltan Haiman, an astronomy professor at Columbia University. “A few hundred-million years later, it has grown into a billion-solar-mass supermassive black hole. This is much faster than we expected.”

    In the early universe, stars and galaxies formed as molecular hydrogen cooled and deflated a primordial plasma of hydrogen and helium. This environment would have limited black holes from growing very big as molecular hydrogen turned gas into stars far enough away to escape the black holes’ gravitational pull. Astronomers have come up with several ways that supermassive black holes might have overcome this barrier.

    In a 2008 study, Haiman and his colleagues hypothesized that radiation from a massive neighboring galaxy could split molecular hydrogen into atomic hydrogen and cause the nascent black hole and its host galaxy to collapse rather than spawn new clusters of stars.

    A later study led by Eli Visbal, then a postdoctoral researcher at Columbia, calculated that the nearby galaxy would have to be at least 100 million times more massive than our sun to emit enough radiation to stop star-formation. Though relatively rare, enough galaxies of this size exist in the early universe to explain the supermassive black holes observed so far.

    The current study, led by John Regan, a postdoctoral researcher at Ireland’s Dublin City University, modeled the process using software developed by Columbia’s Greg Bryan, and includes the effects of gravity, fluid dynamics, chemistry and radiation.

    After several days of crunching the numbers on a supercomputer, the researchers found that the neighboring galaxy could be smaller and closer than previously estimated. “The nearby galaxy can’t be too close, or too far away, and like the Goldilocks principle, too hot or too cold,” said study coauthor John Wise, an associate astrophysics professor at Georgia Tech.

    Though massive black holes are found at the center of most galaxies in the mature universe, including our own Milky Way, they are far less common in the infant universe. The earliest supermassive black holes were first sighted in 2001 through a telescope at New Mexico’s Apache Point Observatory as part of the Sloan Digital Sky Survey.


    SDSS Telescope at Apache Point Observatory, NM, USA

    The researchers hope to test their theory when NASA’s James Webb Space Telescope, the successor to Hubble, goes online next year and beams back images from the early universe.

    Other models of how supermassive black holes evolved, including one in which black holes grow by merging with millions of smaller black holes and stars, await further testing. “Understanding how supermassive black holes form tells us how galaxies, including our own, form and evolve, and ultimately, tells us more about the universe in which we live,” said Regan, at Dublin City University.

    See the full article here .

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    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

     
  • richardmitnick 1:19 pm on December 3, 2016 Permalink | Reply
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    From Columbia U. : “Increasing tornado outbreaks—Is climate change responsible?” 

    Columbia U bloc

    Columbia University

    Dec. 1, 2016
    No writer credit found

    1

    Study raises new questions about what climate change will do to tornado outbreaks and what is responsible for recent trends.

    Tornadoes and severe thunderstorms kill people and damage property every year. Estimated U.S. insured losses due to severe thunderstorms in the first half of 2016 were $8.5 billion. The largest U.S. impacts of tornadoes result from tornado outbreaks, sequences of tornadoes that occur in close succession. Last spring a research team led by Michael Tippett, associate professor of applied physics and applied mathematics at Columbia Engineering, published a study showing that the average number of tornadoes during outbreaks—large-scale weather events that can last one to three days and span huge regions—has risen since 1954. But they were not sure why.

    In a new paper, published December 1 in Science via First Release, the researchers looked at increasing trends in the severity of tornado outbreaks where they measured severity by the number of tornadoes per outbreak. They found that these trends are increasing fastest for the most extreme outbreaks. While they saw changes in meteorological quantities that are consistent with these upward trends, the meteorological trends were not the ones expected under climate change.

    “This study raises new questions about what climate change will do to severe thunderstorms and what is responsible for recent trends,” says Tippett, who is also a member of the Data Science Institute and the Columbia Initiative on Extreme Weather and Climate. “The fact that we don’t see the presently understood meteorological signature of global warming in changing outbreak statistics leaves two possibilities: either the recent increases are not due to a warming climate, or a warming climate has implications for tornado activity that we don’t understand. This is an unexpected finding.”

    The researchers used two NOAA datasets, one containing tornado reports and the other observation-based estimates of meteorological quantities associated with tornado outbreaks. “Other researchers have focused on tornado reports without considering the meteorological environments,” notes Chiara Lepore, associate research scientist at the Lamont-Doherty Earth Observatory, who is a coauthor of the paper. “The meteorological data provide an independent check on the tornado reports and let us check for what would be expected under climate change.”

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    Annual 20th, 40th, 60th and 80th percentiles of the number of E/F1+ tornadoes per outbreak (6 or more E/F1+ tornadoes), 1954-2015 (solid lines), and quantile regression fits to 1965-2015 assuming linear growth in time (dashed lines).—Figure by Michael Tippett

    U.S. tornado activity in recent decades has been drawing the attention of scientists. While no significant trends have been found in either the annual number of reliably reported tornadoes or of outbreaks, recent studies indicate increased variability in large normalized economic and insured losses from U.S. thunderstorms, increases in the annual number of days on which many tornadoes occur, and increases in the annual mean and variance of the number of tornadoes per outbreak. In the current study, the researchers used extreme value analysis and found that the frequency of U.S. outbreaks with many tornadoes is increasing, and is increasing faster for more extreme outbreaks. They modeled this behavior using extreme value distributions with parameters that vary to match the trends in the data.

    Extreme meteorological environments associated with severe thunderstorms showed consistent upward trends, but the trends did not resemble those currently expected to result from global warming. The researchers looked at two factors: convective available potential energy (CAPE) and a measure of vertical wind shear, storm relative helicity. Modeling studies have projected that CAPE will increase in a warmer climate leading to more frequent environments favorable to severe thunderstorms in the U.S. However, they found that the meteorological trends were not due to increasing CAPE but instead due to trends in storm relative helicity, which has not been projected to increase under climate change.

    “Tornadoes blow people away, and their houses and cars and a lot else,” says Joel Cohen, coauthor of the paper and director of the Laboratory of Populations, which is based jointly at Rockefeller University and Columbia’s Earth Institute. “We’ve used new statistical tools that haven’t been used before to put tornadoes under the microscope. The findings are surprising. We found that, over the last half century or so, the more extreme the tornado outbreaks, the faster the numbers of such extreme outbreaks have been increasing. What’s pushing this rise in extreme outbreaks is far from obvious in the present state of climate science. Viewing the thousands of tornadoes that have been reliably recorded in the U.S. over the past half century or so as a population has permitted us to ask new questions and discover new, important changes in outbreaks of these tornadoes.”

    Adds Harold Brooks, senior scientist at NOAA’s National Severe Storms Laboratory, who was not involved with this project, “The study is important because it addresses one of the hypotheses that has been raised to explain the observed change in number of tornadoes in outbreaks. Changes in CAPE can’t explain the change. It seems that changes in shear are more important, but we don’t yet understand why those have happened and if they’re related to global warming.”

    Better understanding of how climate affects tornado activity can help to predict tornado activity in the short-term, a month, or even a year in advance, and would be a major aid to insurance and reinsurance companies in assessing the risks posed by outbreaks. “An assessment of changing tornado outbreak size is highly relevant to the insurance industry,” notes Kelly Hererid, AVP, Senior Research Scientist, Chubb Tempest Re R&D. “Common insurance risk management tools like reinsurance and catastrophe bonds are often structured around storm outbreaks rather than individual tornadoes, so an increasing concentration of tornadoes into larger outbreaks provides a mechanism to change loss potential without necessarily altering the underlying tornado count. This approach provides an expanded view of disaster potential beyond simple changes in event frequency.”

    Tippett notes that more studies are needed to attribute the observed changes to either global warming or another component of climate variability. The research group plans next to study other aspects of severe thunderstorms such as hail, which causes less intense damage but is important for business (especially insurance and reinsurance) because it affects larger areas and is responsible for substantial losses every year.

    The study was partially funded by Columbia University Research Initiatives for Science and Engineering (RISE) award; the Office of Naval Research; NOAA’s Climate Program Office’s Modeling, Analysis, Predictions and Projections; Willis Research Network; and the National Science Foundation.

    See the full article here .

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    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

     
  • richardmitnick 7:55 am on September 23, 2016 Permalink | Reply
    Tags: Columbia U, Hybrid Organic Inorganic Perovskites (HOIPs), More Efficient Solar Cells   

    From Columbia U: “Columbia Chemists Find Key to Manufacturing More Efficient Solar Cells” 

    Columbia U bloc

    Columbia University

    September 22, 2016
    No writer credit found

    1
    A new class of solar cells – Graphic by Nicoletta Barolini

    In a discovery that could have profound implications for future energy policy, Columbia scientists have demonstrated it is possible to manufacture solar cells that are far more efficient than existing silicon energy cells by using a new kind of material, a development that could help reduce fossil fuel consumption.

    The team, led by Xiaoyang Zhu, a professor of Chemistry at Columbia University, focused its efforts on a new class of solar cell ingredients known as Hybrid Organic Inorganic Perovskites (HOIPs). Their results, reported in the prestigious journal Science, also explain why these new materials are so much more efficient than traditional solar cells—solving a mystery that will likely prompt scientists and engineers to begin inventing new solar materials with similar properties in the years ahead.

    “The need for renewable energy has motivated extensive research into solar cell technologies that are economically competitive with burning fossil fuel,” Zhu says. “Among the materials being explored for next generation solar cells, HOIPs have emerged a superstar. Until now no one has been able to explain why they work so well, and how much better we might make them. We now know it’s possible to make HOIP-based solar cells even more efficient than anyone thought possible.”

    Solar cells are what turn sunlight into electricity. Also known as photovoltaic cells, these semiconductors are most frequently made from thin layers of silicon that transmit energy across its structure, turning it into DC current.

    Silicon panels, which currently dominate the market for solar panels, must have a purity of 99.999 percent and are notoriously fragile and expensive to manufacture. Even a microscopic defect—such as misplaced, missing or extra ions—in this crystalline structure can exert a powerful pull on the charges the cells generate when they absorb sunlight, dissipating those charges before they can be transformed into electrical current.

    In 2009, Japanese scientists demonstrated it was possible to build solar cells out of HOIPs, and that these cells could harvest energy from sunlight even when the crystals had a significant number of defects. Because they don’t need to be pristine, HOIPs can be produced on a large scale and at low cost. The Columbia team has been investigating HOIPs since 2014. Their findings could help boost the use of solar power, a priority in the age of global warming.

    Over the last seven years, scientists have managed to increase the efficiency with which HOIPs can convert solar energy into electricity, to 22 percent from 4 percent. By contrast, it took researchers more than six decades to create silicon cells and bring them to their current level, and even now silicon cells can convert no more than about 25 percent of the sun’s energy into electrical current.

    This discovery, Zhu said, meant that “scientists have only just begun to tap the potential of HOIPs to convert the sun’s energy into electricity.”

    Theorists long ago demonstrated that the maximum efficiency silicon solar cells might ever reach— the percentage of energy in sunlight that might be converted to electricity we can use—is roughly 33 percent. It takes hundreds of nanoseconds for energized electrons to move from the part of a solar cell that infuses them with the sun’s energy, to the part of the cell that harvests the energy and converts it into electricity that can ultimately be fed into a power grid. During this migration across the solar cell, the energized electrons quickly dissipate their excess energy. But those calculations assume a specific rate of energy loss. The Columbia team discovered that the rate of energy loss is slowed down by over three-orders of magnitude in HOIPs – making it possible for the harvesting of excess electronic energy to increase the efficiency of solar cells.

    “We’re talking about potentially doubling the efficiency of solar cells,” says Prakriti P. Joshi, a Ph.D. student in Zhu’s lab who is a coauthor on the paper. “That’s really exciting because it opens up a big, big field in engineering.” Adds Zhu, “This shows we can push the efficiencies of solar cells much higher than many people thought possible.”

    After demonstrating this, the team then turned to the next question: what is it about the molecular structure of HOIPs that gives them their unique properties? How do electrons avoid defects? They discovered that the same mechanism that slows down the cooling of electron energy also protects the electrons from bumping into defects. This “protection” makes the HOIPs turn a blind eye to the ubiquitous defects in a material developed from room-temperature and solution processing, thus allowing an imperfect material to behave like a perfect semiconductor.

    HOIPs contain lead, and are also water soluble, meaning the solar cells could begin to dissolve and leach lead into the environment around them if not carefully protected from the elements.

    With the explanation of the mysterious mechanisms that give HOIPs their remarkable efficiencies, Zhu knew, material scientists would likely be able to mimic them with more environmentally-friendly materials.

    “Now we can go back and design materials which are environmentally benign and really solve this problem everybody is worried about,” Zhu says. “This principle will allow people to start to design new materials for solar energy.”

    The research team was spearheaded by Haiming Zhu and Kiyoshi Miyata, two postdoctoral fellows at Columbia. Other members include graduate students Jue Wang, Prakriti P. Joshi, Kristopher W. Williams and postdoc Daniel Niesner, all of Columbia; Yongping Fu and Song Jin, collaborators from the University of Wisconsin–Madison; and the team was led by Columbia Chemistry Prof. Xiaoyang Zhu. This research received funding from the U.S. Department of Energy and the National Science Foundation.

    See the full article here .

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    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

     
  • richardmitnick 10:04 am on June 26, 2016 Permalink | Reply
    Tags: , , Columbia U, Contagious Cancers Are Spreading Among Several Species of Shellfish,   

    From Columbia: “Contagious Cancers Are Spreading Among Several Species of Shellfish, Study Finds” 

    Columbia U bloc

    Columbia University

    June 22, 2016
    No writer credit found


    Acess mp4 video here .

    Direct transmission of cancer among some marine animals may be more common than once thought, suggests a new study published in Nature by researchers at Columbia University Medical Center (CUMC).

    The study, led by Stephen Goff, PhD, the Higgins Professor of Biochemistry in the Department of Biochemistry & Molecular Biophysics and the Department of Microbiology & Immunology at CUMC in collaboration with researchers from Canada and Spain, revealed that in several species of bivalves, including mussels, cockles, and clams, cancer cells spread from animal to animal through the sea water. The cancer, known as disseminated neoplasia, is a leukemia-like disease that affects bivalves in many parts of the world.

    Direct transmission of cancer cells is quite rare. Until recently, the phenomenon had only been observed in two species of mammals.

    Last year, Dr. Goff’s team found a third example in the soft shell clam (Mya arenaria) after initially suspecting that the culprit behind the cancer cluster was a virus.

    The team then wondered if cancers in other mollusks are also caused by contagious cells. To find out, Dr. Goff’s team examined the DNA of cancers and normal tissue from mussels (Mytilus trossulus), cockles (Cerastoderma edule), and golden carpet shell clams (Polititapes aureus) collected from the coasts of Canada and Spain.

    In each species, the researchers discovered that the cancers were caused by independent clones of cancer cells that were genetically distinct from their hosts. They also found that in one species, the carpet shell clam, the infectious cancer cells came from a related but distinct species. The researchers concluded that this cancer was due to a case of cross-species transmission.

    “Now that we have observed the spread of cancer among several marine species, our future research will investigate the mutations that are responsible for these cancer cell transmissions,” said Dr. Goff.

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    Left to right: 1. Mussels (Mytilus trossulus) at Copper Beach in West Vancouver, Canada 2. Cockles (Cerastoderma edule) collected in the ria of Arousa in Galicia, Spain 3. Golden carpet shell clams (Polititapes aureus) collected in the ria of Arousa in Galicia, Spain

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    Tumor cells in cockle tissue. (Credit: Antonio Villalba and María J. Carballal)

    About

    The study is titled, Widespread transmission of independent cancer lineages within multiple bivalve species. Additional authors are Michael Metzger (Columbia University Medical Center and Howard Hughes Medical Institute, New York, NY); Antonio Villalba (Centro de Investigacións Mariñas, Vilanova de Arousa, and University of Alcalá, Alcalá, Spain); Maria J. Carballal, and David Iglesias (Centro de Investigacións Mariñas); James Sherry and Carol Reinisch (Environment Canada, Burlington, Ontario, Canada); Annette Muttray (University of British Columbia and SLR Consulting Canada, Vancouver, Canada); and Susan Baldwin (University of British Columbia).

    Support for the study was provided by the Howard Hughes Medical Institute and Training Grant T32 CA009503. Additional support was provided by the Consellería do Mar da Xunta de Galicia, project PGIDIT-CIMA 13/03.

    The researchers declare no conflicts of interest.

    See the full article here .

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  • richardmitnick 6:40 pm on January 3, 2016 Permalink | Reply
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    From Columbia: “An Eye Doctor’s Tool Helps With Brain Tumor Removal” 

    Columbia U bloc

    Columbia University

    Dec 25, 2015
    No writer credit found

    Temp 1

    Has your child’s primary care doctor seen him for eye pain or a scratch on the cornea? If so, she may have used a dye and a fluorescent light to look for problems.

    It turns out that this same dye may help neurosurgeons to identify and more easily remove brain tumor tissue. Dr. Neil Feldstein, Dr. Jeffrey Bruce and their team recently reported on their experience using the dye, known as fluorescein sodium, to aid in the safe removal of a brain tumor called a tectal plate glioma.

    A glioma is a tumor of the brain involving cells that hold the nerves in place. The tectal plate lies in an area of the brain called the midbrain. As its name implies, it’s located below the frontal area, which controls thinking, and above the base area, which controls functions such as breathing. However, many important parts of the brain are located near the tectum, including those that control hearing, vision and movement of the eyes.

    Also nearby is a canal that helps drain fluid from the brain. When a tumor grows, the fluid doesn’t drain as easily, leading to a condition called hydrocephalus (excess fluid in the brain), which can cause symptoms such as headache and vomiting.

    Many tectal plate gliomas can be watched or controlled without surgery. Most commonly, chemotherapy is used. However, the patient described by Drs. Feldstein and Bruce had a potentially more serious type of tumor that needed to be removed. Because of the structures near the tumor, surgery would be more difficult than in many other areas of the brain.

    Fortunately, fluorescein sodium dye—that same orange dye used by doctors to view scratches on the cornea—will enter tumor tissue, but not normal brain tissue, when given through a peripheral vein (intravenously). Cells of normal brain tissue keep many chemicals from entering the brain from the bloodstream. However, tumor cells don’t have this ability and will let the fluorescein enter. When it does, the surgeon can view the dye by using a special light filter, which turns the tumor tissue a bright green.

    As they reported in the Journal of Neurosurgery: Pediatrics, Drs. Feldstein and Bruce and their team used fluorescein dye during surgery on the patient. Since the surgeons were able to more accurately see what was tumor tissue and what was normal, they were able to completely remove the tumor and leave normal brain tissue intact. They have found fluorescein to be both safe and effective.

    See the full article here .

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  • richardmitnick 5:14 pm on September 16, 2015 Permalink | Reply
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    From Columbia: “New Support For Converging Black Holes” 

    Columbia U bloc

    Columbia University

    Sep 16 2015
    Kim Martineau

    Crash Expected in 100,000 Years – Far Sooner than Previously Predicted, Says Study

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    Columbia researchers predict that a pair of converging supermassive black holes in the Virgo constellation will collide sooner than expected. Above, an artist’s conception of a merger. (P. Marenfeld/NOAO/AURA/NSF)

    Earlier this year, astronomers discovered what appeared to be a pair of supermassive black holes circling toward a collision so powerful it would send a burst of gravitational waves surging through the fabric of space-time itself.

    Now, in a new study in the journal Nature, astronomers at Columbia University provide additional evidence that a pair of closely orbiting black holes is causing the rhythmic flashes of light coming from quasar PG 1302-102.

    Based on calculations of the pair’s mass—together, and relative to each other—the researchers go on to predict a smashup 100,000 years from now, an impossibly long time to humans but the blink of an eye to a star or black hole. Spiraling together 3.5 billion light-years away, deep in the Virgo constellation, the pair is separated by a mere light-week. By contrast, the closest previously confirmed black hole pair is separated by 20 light-years.

    “This is the closest we’ve come to observing two black holes on their way to a massive collision,” said the study’s senior author, Zoltan Haiman, an astronomer at Columbia. “Watching this process reach its culmination can tell us whether black holes and galaxies grow at the same rate, and ultimately test a fundamental property of space-time: its ability to carry vibrations called gravitational waves, produced in the last, most violent, stage of the merger.”

    At the center of most giant galaxies, including our own Milky Way, lies a supermassive black hole so dense that not even light can escape. Over time, black holes grow bigger—millions to billions times more massive than the sun–by gobbling up stars, galaxies and even other black holes.

    A supermassive black hole about to cannibalize its own can be detected by the mysterious flickering of a quasar—the beacon of light produced by black holes as they burn through gas and dust swirling around them. Normally, quasars brighten and dim randomly, but when two black holes are on the verge of uniting, the quasar appears to flicker at regular intervals, like a light bulb on timer.

    Recently, a team led by Matthew Graham, a computational astronomer at the California Institute of Technology, designed an algorithm to pick out repeating light signals from 247,000 quasars monitored by telescopes in Arizona and Australia. Of the 20 pairs of black hole candidates discovered, they focused on the most compelling brightquasar– PG 1302-102. In a January study in Nature, they showed that PG 1302-102 appeared to brighten by 14 percent every five years, indicating the pair was less than a tenth of a light-year apart.

    Intrigued, Haiman and his colleagues wondered if they could build a theoretical model to explain the repeating signal. If the black holes were as close as predicted, one had to be circling a much larger counterpart at nearly a tenth ofthe speed of light, they hypothesized. At that speed, the smaller black hole would appear to brighten as it approached Earth’s line of sight under the relativistic Doppler beaming effect.

    If correct, they predicted they would find a five-year cycle in the quasar’s ultraviolet emissions—only two-and-a-half times more variable in its intensity. Analyzing UV observations collected by NASA’s Hubble and GALEX space telescopes they found exactly that.

    Previous explanations for the repeating signal include a warp in the debris disks orbiting the black holes, a wobble in the axis of one black hole and a lopsided debris disk formed as one black hole draws material off the other–all creating the impression of a periodic flicker from Earth.

    See the full article here .

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    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

     
  • richardmitnick 8:38 pm on February 5, 2015 Permalink | Reply
    Tags: , Columbia U, MId-ocean ridges, ,   

    From Columbia: “Seafloor Volcano Pulses May Alter Climate” 

    Columbia U bloc

    Columbia University

    Columbia U Lamont Doherty Earth Observatory

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    An ocean-bottom seismometer (sailboat-like object) was trapped amid erupting magma in 2006 at the East Pacific Rise. Such instruments are providing new insights into the timing of eruptions. (Dan Fornari/Woods Hole Oceanographic Institution)

    Vast ranges of volcanoes hidden under the oceans are presumed by scientists to be the gentle giants of the planet, oozing lava at slow, steady rates along mid-ocean ridges. But a new study shows that they flare up on strikingly regular cycles, ranging from two weeks to 100,000 years—and, that they erupt almost exclusively during the first six months of each year. The pulses—apparently tied to short- and long-term changes in earth’s orbit, and to sea levels–may help trigger natural climate swings. Scientists have already speculated that volcanic cycles on land emitting large amounts of carbon dioxide might influence climate; but up to now there was no evidence from submarine volcanoes. The findings suggest that models of earth’s natural climate dynamics, and by extension human-influenced climate change, may have to be adjusted. The study appears this week in the journal Geophysical Research Letters.

    “People have ignored seafloor volcanoes on the idea that their influence is small—but that’s because they are assumed to be in a steady state, which they’re not,” said the study’s author, marine geophysicist Maya Tolstoy of Columbia University’s Lamont-Doherty Earth Observatory. “They respond to both very large forces, and to very small ones, and that tells us that we need to look at them much more closely.” A related study by a separate team this week in the journal Science bolsters Tolstoy’s case by showing similar long-term patterns of submarine volcanism in an Antarctic region Tolstoy did not study.

    Volcanically active mid-ocean ridges crisscross earth’s seafloors like stitching on a baseball, stretching some 37,000 miles. They are the growing edges of giant tectonic plates; as lavas push out, they form new areas of seafloor, which comprise some 80 percent of the planet’s crust. Conventional wisdom holds that they erupt at a fairly constant rate–but Tolstoy finds that the ridges are actually now in a languid phase. Even at that, they produce maybe eight times more lava annually than land volcanoes. Due to the chemistry of their magmas, the carbon dioxide they are thought to emit is currently about the same as, or perhaps a little less than, from land volcanoes—about 88 million metric tons a year. But were the undersea chains to stir even a little bit more, their CO2 output would shoot up, says Tolstoy.

    3
    Magma from undersea eruptions congealed into forms known as pillow basalts on the Juan De Fuca Ridge, off the U.S. Pacific Northwest. A new study shows such eruptions wax and wane on regular schedules. (Deborah Kelley/University of Washington)

    Some scientists think volcanoes may act in concert with Milankovitch cycles–repeating changes in the shape of earth’s solar orbit, and the tilt and direction of its axis—to produce suddenly seesawing hot and cold periods. The major one is a 100,000-year cycle in which the planet’s orbit around the sun changes from more or less an annual circle into an ellipse that annually brings it closer or farther from the sun. Recent ice ages seem to build up through most of the cycle; but then things suddenly warm back up near the orbit’s peak eccentricity. The causes are not clear.

    Enter volcanoes. Researchers have suggested that as icecaps build on land, pressure on underlying volcanoes also builds, and eruptions are suppressed. But when warming somehow starts and the ice begins melting, pressure lets up, and eruptions surge. They belch CO2 that produces more warming, which melts more ice, which creates a self-feeding effect that tips the planet suddenly into a warm period. A 2009 paper from Harvard University says that land volcanoes worldwide indeed surged six to eight times over background levels during the most recent deglaciation, 12,000 to 7,000 years ago. The corollary would be that undersea volcanoes do the opposite: as earth cools, sea levels may drop 100 meters, because so much water gets locked into ice. This relieves pressure on submarine volcanoes, and they erupt more. At some point, could the increased CO2 from undersea eruptions start the warming that melts the ice covering volcanoes on land?

    That has been a mystery, partly because undersea eruptions are almost impossible to observe. However, Tolstoy and other researchers recently have been able to closely monitor 10 submarine eruption sites using sensitive new seismic instruments. They have also produced new high-resolution maps showing outlines of past lava flows. Tolstoy analyzed some 25 years of seismic data from ridges in the Pacific, Atlantic and Arctic oceans, plus maps showing past activity in the south Pacific.

    4
    Alternating ridges and valleys formed by volcanism near the East Pacific Rise, a mid-ocean ridge in the Pacific Ocean. Such formations indicate ancient highs and lows of volcanic activity. (Haymon et al., NOAA-OE, WHOI)

    The long-term eruption data, spread over more than 700,000 years, showed that during the coldest times, when sea levels are low, undersea volcanism surges, producing visible bands of hills. When things warm up and sea levels rise to levels similar to the present, lava erupts more slowly, creating bands of lower topography. Tolstoy attributes this not only to the varying sea level, but to closely related changes in earth’s orbit. When the orbit is more elliptical, Earth gets squeezed and unsqueezed by the sun’s gravitational pull at a rapidly varying rate as it spins daily—a process that she thinks tends to massage undersea magma upward, and help open the tectonic cracks that let it out. When the orbit is fairly (though not completely) circular, as it is now, the squeezing/unsqueezing effect is minimized, and there are fewer eruptions.

    The idea that remote gravitational forces influence volcanism is mirrored by the short-term data, says Tolstoy. She says the seismic data suggest that today, undersea volcanoes pulse to life mainly during periods that come every two weeks. That is the schedule upon which combined gravity from the moon and sun cause ocean tides to reach their lowest points, thus subtly relieving pressure on volcanoes below. Seismic signals interpreted as eruptions followed fortnightly low tides at eight out of nine study sites. Furthermore, Tolstoy found that all known modern eruptions occur from January through June. January is the month when Earth is closest to the sun, July when it is farthest—a period similar to the squeezing/unsqueezing effect Tolstoy sees in longer-term cycles. “If you look at the present-day eruptions, volcanoes respond even to much smaller forces than the ones that might drive climate,” she said.

    Daniel Fornari, a senior scientist at Woods Hole Oceanographic Institution not involved in the research, called the study “a very important contribution.” He said it was unclear whether the contemporary seismic measurements signal actual lava flows or just seafloor rumbles and cracking. But, he said, the study “clearly could have important implications for better quantifying and characterizing our assessment of climate variations over decadal to tens to hundreds of thousands of years cycles.”

    Edward Baker, a senior ocean scientist at the National Oceanic and Atmospheric Administration, said, “The most interesting takeaway from this paper is that it provides further evidence that the solid Earth, and the air and water all operate as a single system.”

    The research for this paper was funded in large part by the U.S. National Science Foundation.

    See the full article here.

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