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  • richardmitnick 8:57 pm on September 22, 2014 Permalink | Reply
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    From Astronomy: “Most metal-poor star hints at universe’s first supernovae” 

    Astronomy magazine

    Astronomy Magazine

    Monday, September 22, 2014
    No Writer Credit

    Typical massive stars could have produced this star’s elemental abundance if they underwent a special type of explosion.
    Artist’s conception of a supernova of a first star with jets. Kavli IPMU

    A team of researchers led by Miho N. Ishigaki at the Kavli IPMU, the University of Tokyo, pointed out that the elemental abundance of the most iron-poor star can be explained by elements ejected from supernova explosions of the universe’s first stars. Their theoretical study revealed that massive stars, which are several tens of times more immense than the Sun, were present among the first stars. The presence of these massive stars has great implications on the theory of star formation in the absence of heavy elements.

    Iron-poor stars provide insight about the early universe where the first generation of stars and galaxies formed. The recent discovery of the most iron-poor star SMSS J031300.36–670839.3 (SMSS J0313–6708) was big news in early 2014, especially for astronomers working on so-called “galactic archaeology.”

    When the universe first began, only light elements such as hydrogen and helium existed. As these first stars ended their short but wild lives, the universe became enriched with heavy elements, which are essential to form the materials found on Earth, including humans. Hence, iron-poor stars are much older than the Sun and were born when the universe only contained trace amounts of heavy elements.

    SMSS J0313–6708 is the most iron-poor star ever found. Its spectrum lacks iron absorption lines. The estimated upper limit for its iron abundance is about a ten-millionth of that of the Sun, and its iron content is about a hundred times lower than the previous record for the most iron-poor star.

    “We received the news of the most iron-poor star with a great excitement,” Ken’ichi Nomoto at the Kavli IPMU said, “since this star may be the oldest fossil record and may elucidate the unknown nature of the first stars.” The first stars, which formed in the early universe, likely had a large impact on their environments. For example, the strong ultraviolet light emitted by the first stars helped ionize the early universe. In addition, their supernova explosions ejected heavy elements that have helped form subsequent generations of stars and galaxies.

    “The impact of these stars on the surrounding environment depends critically on their masses when they were born,” Ishigaki said. “However, direct observational constraints of the first stars’ masses are not available since most of them likely died out a long, long time ago.”

    Due to its unusual chemical composition, some astrophysicists have speculated that SMSS J0313–6708 was born from the gas enriched by a first star, which has a mass 60 times that of the Sun, and synthesized a small amount of calcium through a special nucleosynthesis.

    On the other hand, Ishigaki’s team focused on its very large carbon enhancement relative to iron and calcium. Previous studies by Nozomu Tominaga at Konan University/Kavli IPMU suggested that such a feature is consistent with a supernova in which the synthesized elements fall back. However, the question was whether this scenario can also explain the most extreme abundance pattern in SMSS J0313–6708, the most iron-poor star.

    The team compared the observed abundances and theoretical calculations of the elements ejected by the supernova of first stars with masses 25 and 40 times that of the Sun. They concluded that the observed abundance pattern can be reproduced if stars with those masses undergo a special type of supernova in which most of the ejected matter falls back to the central remnant. A highly asymmetric explosion involving a jet-like feature should produce this type of supernova. As a consequence of the jet, iron and calcium, which are located deep inside massive stars, are ejected along with the jet, but a large fraction of the ejected material falls back along the equatorial plane. Because carbon is largely contained in the outer region, it is almost entirely ejected without falling back. This model successfully explains the low abundance of calcium, the non-detection of iron, and the high abundance of carbon observed in SMSS J0313–6708.

    “If such supernovae are actually possible,” Nomoto said, “the result supports the theoretical prediction that the first stars could be typical massive stars rather than monster-like objects with masses more than several hundred times that of the Sun.” Since heavy elements play a role in star formation through the gravitational pull of interstellar gas, the first stars, which formed without heavy elements, should display quite different characteristics compared to what is typically observed in the present Milky Way Galaxy. In particular, without heavy elements, some researchers have suggested that stars could be as massive as a few hundred times that of the Sun. The presence of stars much less massive than such monster-like objects among the first stars may affect the theory of star formation in the absence of heavy elements. In future studies, researchers should employ simulations for the formation of the first stars in the early universe that reproduce the present result.

    “The next issue is to determine if these less massive stars are typical first stars,” Ishigaki said. “In the near future, more data from a number of iron-poor stars will be available. Applying the method we used in this study to these data will shed light on the unknown nature of the first stars.”

    See the full article here.

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  • richardmitnick 8:40 pm on September 22, 2014 Permalink | Reply
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    From Huff Post: “Will ET Be Here Soon? NASA Brings Scientists, Theologians Together To Prepare” 

    Huffington Post
    The Huffington Post

    Lee Speigel

    Looking for extraterrestrial life is akin to a search for a cosmic needle-in-a-haystack, as evidenced by the above incredible Hubble Space Telescope image showing approximately 10,000 galaxies.


    NASA Hubble Telescope
    NASA/ESA HUbble

    In large part, thanks to NASA’s Kepler spacecraft, more than 1,400 planets have been identified beyond Earth.

    NASA Kepler Telescope

    A few days ago, NASA tried closing the gap between life on Earth and the possibilities of life elsewhere. The space agency and the Library of Congress (image below left) brought together scientists, historians, philosophers and theologians from around the world for a two-day symposium, “Preparing For Discovery.” Their agenda: To explore how we prepare for the inevitable discovery of extraterrestrial life, be it simple microbial organisms or intelligent beings.


    “We’re looking at all scenarios about finding life. If you find microbes, that’s one thing. If you find intelligence, it’s another. And if they communicate, it’s something else, and depending on what they say, it’s something else!” said astronomer, symposium organizer and former chief NASA historian, Steven J. Dick.

    “The idea is not to wait until we make a discovery, but to try and prepare the public for what the implications might be when such a discovery is made,” Dick told The Huffington Post. “I think the reason that NASA is backing this is because of all the recent activity in the discovery of exoplanets and the advances in astrobiology in general.

    “People just consider it much more likely now that we’re going to find something — probably microbes first and maybe intelligence later,” he added. “The driving force behind this is from a scientific point of view that it seems much more likely now that we are going to find life at some point in the future.”

    Among the many speakers at last week’s astrobiology symposium, one has raised a few international eyebrows in recent years.

    “I believe [alien life exists], but I have no evidence. I would be really excited and it would make my understanding of my religion deeper and richer in ways that I can’t even predict yet, which is why it would be so exciting,” Brother Guy Consolmagno, a Jesuit priest, astronomer and Vatican planetary scientist told HuffPost senior science editor David Freeman.

    Consolmagno has publicly stated his belief that “any entity — no matter how many tentacles it has — has a soul,” and he’s suggested that he would be happy to baptize any ETs, as long as they requested it.

    “There has to be freedom to do science. Being a good scientist means admitting we never have the whole truth — there’s always more to learn.” Consolmagno also doesn’t think the public would panic when or if it’s revealed that alien life has been found.

    “I really think it would be a three-day wonder and then we’d go back to worrying about reality TV or the crazy things going on in Washington — that’s the way human beings are. Because I think most people are like me: we expect it’s out there. And our reaction would be, ‘Wow, thank heavens. It’s about time.”

    Earth is no longer the center of the universe, nor is it flat — at least that’s the currently accepted thinking among most scientists. And we now know, conclusively, that there are a lot more planets than the ones in our own solar system.

    “The number of habitable worlds in our galaxy is certainly in the tens of billions, minimum, and we haven’t even talked about the moons. And the number of galaxies we can see, other than our own, is about 100 billion,” Seth Shostak, senior astronomer at California’s SETI Institute told HuffPost.

    At the NASA/Library of Congress symposium, Shostak gave out some startling numbers about how many stars there are in the part of the universe that we can see. “It’s a big number: 10,000 billion, billion. And we know that most of those stars have planets — 70 or 80 percent. If all of those planets are sterile, and you’re the only interesting thing happening in the cosmos, then you are a miracle. That would be exceptional in the extreme. So, the middle-of-the-road approach is to say, ‘You’re not a miracle, you’re just another duck in a row of ducks.'”

    “The bottom line of this,” Shostak said, “is something like one in five of all stars may have an analog to Earth. That’s a lot of habitable worlds, and, indeed, the number of Earths in our own galaxy might be on the order of 50 billion.”

    Those are big numbers to ponder.

    The D.C. conference included a great deal of discussion about the upcoming mission of the Hubble’s long-anticipated successor: the James Webb Space Telescope. As large as a tennis court, this deep space observatory is scheduled for a 2018 launch and will orbit beyond our moon. The Webb telescope will focus on new planetary discoveries and collect data from the atmospheres of those planets, looking for certain things that might point to what we would consider possible indicators of life.

    NASA Webb Telescope
    NASA/ WEbb

    HuffPost asked Dick, an astrobiologist, for his opinion on the continuing output of UFO reports around the world.

    “I try to keep an open mind on this. Ninety-some percent can be explained by natural phenomena, etc. The question is what to do with the other 3 or 4 percent,” Dick said. “My opinion is that they should be studied further, on the one hand. By definition, they’re something that we don’t know what they are. They could be some physical, psychological or social phenomena that we don’t know about. But I think it’s jumping to a conclusion that they’re extraterrestrial. I don’t see that evidence.

    “I haven’t looked at the evidence close enough to say that there’s intelligence behind it. But I’ve seen enough to know that there are unexplained things that we should look at more, and right now, the U.S. government is not doing that.”

    See the full article, with video, here.

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  • richardmitnick 8:15 pm on September 22, 2014 Permalink | Reply
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    From Chandra: “Vela Pulsar Jet: New Chandra Movie Features Neutron Star Action 

    NASA Chandra

    A new Chandra movie of the Vela pulsar shows it may be “precessing,” or wobbling as it spins. This movie contains 8 images from observations taken between June and September 2010. The Vela pulsar, found about 1,000 light years from Earth, formed when a massive star collapsed. The pulsar spins faster than a helicopter rotor and spews out a jet of particles at about 70% the speed of light.

    The included movie [see original post]from NASA’s Chandra X-ray Observatory shows a fast moving jet of particles produced by a rapidly rotating neutron star , and may provide new insight into the nature of some of the densest matter in the universe.

    The star of this movie is the Vela pulsar, a neutron star that was formed when a massive star collapsed. The Vela pulsar is about 1,000 light years from Earth, spans about 12 miles in diameter, and makes over 11 complete rotations every second, faster than a helicopter rotor. As the pulsar whips around, it spews out a jet of charged particles that race out along the pulsar’s rotation axis at about 70% of the speed of light. In this still image from the movie, the location of the pulsar and the 0.7-light-year-long jet are labeled.

    Labeled Vela Pulsar Jet

    The Chandra data shown in the movie, containing 8 images obtained between June and September 2010, suggest that the pulsar may be slowly wobbling, or precessing, as it spins. The shape and the motion of the Vela jet look strikingly like a rotating helix, a shape that is naturally explained byprecession, as shown in this animation. If the evidence for precession of the Vela pulsar is confirmed, it would be the first time that a jet from a neutron star has been found to be precessing in this way.

    One possible cause of precession for a spinning neutron star is that it has become slightly distorted and is no longer a perfect sphere. This distortion might be caused by the combined action of the fast rotation and “glitches”, sudden increases of the pulsar’s rotational speed due to the interaction of the superfluid core of the neutron star with its crust.

    A paper describing these results [was] published in The Astrophysical Journal on January 10, 2013.

    This is the second Chandra movie of the Vela pulsar, with the original having been released in 2003. The first Vela movie contained shorter, unevenly spaced observations so that the changes in the jet were less pronounced and the authors did not argue that precession was occurring. However, based on the same data, Avinash Deshpande of Arecibo Observatory in Puerto Rico and the Raman Research Institute in Bangalore, India, and the late Venkatraman Radhakrishnan, argued in a 2007 paper that the Vela pulsar might be precessing.

    Arecibo Observatory
    Arecibo Observcatory

    The Earth also precesses as it spins, with a period of about 26,000 years. In the future Polaris will no longer be the “north star” and other stars will take its place. The period of the Vela precession is much shorter and is estimated to be about 120 days.

    Wide field Optical and X-ray
    Credit NASA/CXC/Univ of Toronto/M.Durant et al
    Release Date January 7, 2013

    The <a href=””>supernova that formed the Vela pulsar exploded over 10,000 years ago. This optical image from the Anglo-Australian Observatory’s UK Schmidt telescope shows the enormous apparent size of the supernova remnant formed by the explosion. The full size of the remnant is about eight degrees across, or about 16 times the angular size of the moon. The square near the center shows the Chandra image with a larger field-of-view than used for the movie, with the Vela pulsar in the middle.

    Anglo Australian Telescope Exterior
    Anglo Australian Telescope Interior
    Anglo Australian Telescope

    See the full article,with video, here.

    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

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  • richardmitnick 6:44 pm on September 22, 2014 Permalink | Reply
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    From Stanford: “Stanford researchers create ‘evolved’ protein that may stop cancer from spreading” 

    Stanford University Name
    Stanford University

    September 21, 2014
    Tom Abate

    Experimental therapy stopped the metastasis of breast and ovarian cancers in lab mice, pointing toward a safe and effective alternative to chemotherapy.

    A team of Stanford researchers has developed a protein therapy that disrupts the process that causes cancer cells to break away from original tumor sites, travel through the bloodstream and start aggressive new growths elsewhere in the body.

    This process, known as metastasis, can cause cancer to spread with deadly effect.

    “The majority of patients who succumb to cancer fall prey to metastatic forms of the disease,” said Jennifer Cochran, an associate professor of bioengineering who describes a new therapeutic approach in Nature Chemical Biology.

    Today doctors try to slow or stop metastasis with chemotherapy, but these treatments are unfortunately not very effective and have severe side effects.

    The Stanford team seeks to stop metastasis, without side effects, by preventing two proteins – Axl and Gas6 – from interacting to initiate the spread of cancer.

    Axl proteins stand like bristles on the surface of cancer cells, poised to receive biochemical signals from Gas6 proteins.

    When two Gas6 proteins link with two Axls, the signals that are generated enable cancer cells to leave the original tumor site, migrate to other parts of the body and form new cancer nodules.

    To stop this process Cochran used protein engineering to create a harmless version of Axl that acts like a decoy. This decoy Axl latches on to Gas6 proteins in the bloodstream and prevents them from linking with and activating the Axls present on cancer cells.

    In collaboration with Professor Amato Giaccia, co-director of the Radiation Biology Program in the Stanford Cancer Center, the researchers gave intravenous treatments of this bioengineered decoy protein to mice with aggressive breast and ovarian cancers.

    Jennifer Cochran and Amato Giaccia are members of a team of researchers who have developed an experimental therapy to treat metastatic cancer.

    Mice in the breast cancer treatment group had 78 percent fewer metastatic nodules than untreated mice. Mice with ovarian cancer had a 90 percent reduction in metastatic nodules when treated with the engineered decoy protein.

    “This is a very promising therapy that appears to be effective and nontoxic in preclinical experiments,” Giaccia said. “It could open up a new approach to cancer treatment.”

    Giaccia and Cochran are scientific advisors to Ruga Corp., a biotech startup in Palo Alto that has licensed this technology from Stanford. Further preclinical and animal tests must be done before determining whether this therapy is safe and effective in humans.

    Greg Lemke, of the Molecular Neurobiology Laboratory at the Salk Institute, called this “a prime example of what bioengineering can do” to open up new therapeutic approaches to treat metastatic cancer.

    “One of the remarkable things about this work is the binding affinity of the decoy protein,” said Lemke, a noted authority on Axl and Gas6 who was not part of the Stanford experiments.

    “The decoy attaches to Gas6 up to a hundredfold more effectively than the natural Axl,” Lemke said. “It really sops up Gas6 and takes it out of action.”
    Directed evolution

    The Stanford approach is grounded on the fact that all biological processes are driven by the interaction of proteins, the molecules that fit together in lock-and-key fashion to perform all the tasks required for living things to function.

    In nature proteins evolve over millions of years. But bioengineers have developed ways to accelerate the process of improving these tiny parts using technology called directed evolution. This particular application was the subject of the doctoral thesis of Mihalis Kariolis, a bioengineering graduate student in Cochran’s lab.

    Using genetic manipulation, the Stanford team created millions of slightly different DNA sequences. Each DNA sequence coded for a different variant of Axl.

    The researchers then used high-throughput screening to evaluate over 10 million Axl variants. Their goal was to find the variant that bound most tightly to Gas6.

    Kariolis made other tweaks to enable the bioengineered decoy to remain in the bloodstream longer and also to tighten its grip on Gas6, rendering the decoy interaction virtually irreversible.

    Yu Rebecca Miao, a postdoctoral scholar in Giaccia’s lab, designed the testing in animals and worked with Kariolis to administer the decoy Axl to the lab mice. They also did comparison tests to show that sopping up Gas6 resulted in far fewer secondary cancer nodules.

    Irimpan Mathews, a protein crystallography expert at SLAC National Accelerator Laboratory, joined the research effort to help the team better understand the binding mechanism between the Axl decoy and Gas6.

    Protein crystallography captures the interaction of two proteins in a solid form, allowing researchers to take X-ray-like images of how the atoms in each protein bind together. These images showed molecular changes that allowed the bioengineered Axl decoy to bind Gas6 far more tightly than the natural Axl protein.
    Next steps

    Years of work lie ahead to determine whether this protein therapy can be approved to treat cancer in humans. Bioprocess engineers must first scale up production of the Axl decoy to generate pure material for clinical tests. Clinical researchers must then perform additional animal tests in order to win approval for and to conduct human trials. These are expensive and time-consuming steps.

    But these early, hopeful results suggest that the Stanford approach could become a nontoxic way to fight metastatic cancer.

    Glenn Dranoff, a professor of medicine at Harvard Medical School and a leading researcher at the Dana-Farber Cancer Institute, reviewed an advance copy of the Stanford paper but was otherwise unconnected with the research. “It is a beautiful piece of biochemistry and has some nuances that make it particularly exciting,” Dranoff said, noting that tumors often have more than one way to ensure their survival and propagation.

    Axl has two protein cousins, Mer and Tyro3, that can also promote metastasis. Mer and Tyro3 are also activated by Gas6.

    “So one therapeutic decoy might potentially affect all three related proteins that are critical in cancer development and progression,” Dranoff said.

    Erinn Rankin, a postdoctoral fellow in the Giaccia lab, carried out proof of principle experiments that paved the way for this study.

    Other co-authors on the Nature Chemical Biology paper include Douglas Jones, a former doctoral student, and Shiven Kapur, a postdoctoral scholar, both of Cochran’s lab, who contributed to the protein engineering and structural characterization, respectively.

    Cochran said Stanford’s support for interdisciplinary research made this work possible.

    Stanford ChEM-H (Chemistry, Engineering & Medicine for Human Health) provided seed funds that allowed Cochran and Mathews to collaborate on protein structural studies.

    The Stanford Wallace H. Coulter Translational Research Grant Program, which supports collaborations between engineers and medical researchers, supported the efforts of Cochran and Giaccia to apply cutting-edge bioengineering techniques to this critical medical need.

    See the full article here.

    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

    Stanford University Seal

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  • richardmitnick 6:20 pm on September 22, 2014 Permalink | Reply
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    From ALMA: “ALMA Studies Infant Sun-like Solar System to Try and Catch the Wind” 

    ESO ALMA Array

    Monday, 22 September 2014


    Dr. Colette Salyk
    National Optical Astronomy Observatory
    950 N Cherry Ave, Tucson AZ 85719 USA

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 467 6258
    Cell: +56 9 75871963

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 434.242.9559

    Richard Hook
    Public Information Officer, ESO
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory Tokyo, Japan
    Tel: +81 422 34 3630

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have studied a special kind of young star, a T Tauri star, to understand why some have disks that glow weirdly in infrared light while others shine in a more predictable fashion. The answer, researchers speculate, may be due to differences in the wind around these stars.


    T Tauri stars are the infant versions of stars like our Sun. They are relatively normal, medium size-stars that are surrounded by the raw materials to build both rocky and gaseous planets. Though nearly invisible in optical light, these disks shine in both infrared and millimeter-wavelength light.

    “The material in the disk of a T Tauri star usually, but not always, emits infrared radiation with a predictable energy distribution,” said Colette Salyk, an astronomer with the National Optical Astronomical Observatory (NOAO) and lead author on a paper published in the Astrophysical Journal, “some T Tauri stars, however, like to act up by emitting infrared radiation in unexpected ways.”

    To account for the different infrared signature around such similar stars, astronomers propose that winds may be emanating from within some T Tauri stars’ protoplanetary disks. These winds could have important implications for planet formation, potentially robbing the disk of some of the gas required for the formation of giant Jupiter-like planets, or stirring up the disk and causing the building blocks of planets to change location entirely. These winds have been predicted by astronomers, but have never been clearly detected.

    Using ALMA, Salyk and her colleagues looked for evidence of a possible wind in AS 205 N, a T Tauri star located 407 light-years away at the edge of a star-forming region in the constellation Ophiuchus, the Snake Bearer. This star seemed to exhibit the characteristically uneven infrared signature that had intrigued astronomers.

    With ALMA’s exceptional resolution and sensitivity, the researchers were able to study the distribution of carbon monoxide around the star. Carbon monoxide is an excellent tracer for the molecular gas that makes up stars and their planet-forming disks. These studies confirmed that there was indeed gas leaving the disk surface, as would be expected if a wind were present. The properties of the wind, however, did not exactly match expectations.

    This different between observations and expectations could be due to the fact that AS 205 N is actually part of a multiple star system – with a companion dubbed AS 205 S, that is itself a binary star.

    This multiple star arrangement may suggest that the gas is leaving the disk surface because it’s being pulled away by the binary companion star rather than ejected by a wind.

    “We are hoping these new ALMA observations help us better understand winds, but they have also left us with a new mystery,” said Salyk, “Are we seeing winds, or interactions with the companion star?”

    The study’s authors are not pessimistic, however. They plan to continue their research with more ALMA observations, targeting other unusual T Tauri stars, with and without companions, to see whether they show these same features.

    T Tauri stars are named after their prototype star, discovered in 1852 – the third star in the constellation Taurus whose brightness was found to vary erratically. At one point, some 4.5 billion years ago, our Sun was a T Tauri star.

    This work is published in the Astrophysical Journal: other authors include Klaus Pontoppidan, Space Telescope Science Institute; Stuartt Corder, Joint ALMA Observatory; Diego Muñoz, Center for Space Research, Department of Astronomy, Cornell University; and Ke Zhang and Geoffrey Blake, Division of Geological & Planetary Sciences, California Institute of Technology.

    See the full article here.

    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small

    ESO 50


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  • richardmitnick 5:10 pm on September 22, 2014 Permalink | Reply
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    From BNL:”Growth of an Ultra-thin Layered Structure Offers Surprises” 

    Brookhaven Lab

    September 22, 2014
    Laura Mgrdichian

    Many new technologies are based on ultra-thin layered structures that are “grown” using precise deposition techniques. Understanding and ultimately controlling this growth at the atomic level – particularly at the interfaces between these layers, where key properties arise – is essential to imparting these structures with properties tailored to possible applications.

    Researchers from the University of Vermont recently investigated an example of “heteroepitaxial” growth, in which one material is grown on the surface of a second material that has a similar crystal structure as the first. They studied a system of bismuth ferrite (BiFeO3, or BFO) grown on strontium titanate (SrTiO3, or STO). The research is published in the February 20, 2014, edition of Physical Review Letters.

    Simulated “maps” for growing bismuth ferrite on strontium titanate

    BFO is a target for materials science researchers because of its diverse ferroelectric properties and possible applications in developing technologies such as nonvolatile memory and data storage. At the National Synchrotron Light Source, the researchers discovered that the BFO forms clusters that grow and coalesce into a single layer in an unexpected way. They found that their data agree well with the “interrupted coalescence model” (ICM) of layer growth. This finding was a bit of a surprise, but they propose that the model may be applicable to other layered systems.

    BNL NSLS Interior

    “In this system, we saw compact, two-dimensional islands come together efficiently over a range of length scales,” said the study’s corresponding scientist, University of Vermont physicist Randall Headrick. “However, the kinetics of the growth process behave more like droplets than what we expected to observe, which was single-layer clusters that grow exponentially in time. This growth mode has implications for the structure of interfaces and ferroelectric domains in these materials, which will have an impact on domain switching in devices.”

    Headrick and his colleagues used a technique called sputter deposition to apply the BFO atoms to the STO surface and “watched” the growth of the BFO layer using x-ray diffraction at NSLS beamline X21. They saw the BFO quickly form islands of varying sizes, with an average size of about 20 nanometers. The small clusters retained their compact shape as they coalesced into bigger clusters. But, this coalescence was kinetically “frozen” when the clusters reached a critical size, leading to the formation of large connected irregularly shaped regions. In the spaces between, smaller islands continued to form and dot the area.

    The group confirmed these observations by studying the final layered structure with atomic force microscopy and additional x-ray diffraction measurements.

    Atomic Force Microscope at Rutgers University

    This work was supported by the
    Office of Basic Energy Sciences within the U.S. Department of Energy’s Office of Science.

    See the full article here.

    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

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  • richardmitnick 4:45 pm on September 22, 2014 Permalink | Reply
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    From RAS: “Finding hints of gravitational waves in the stars” 

    Royal Astronomical Society

    Royal Astronomical Society

    September 22, 2014

    Media contact

    Kendra Snyder
    Manager of Science Communication
    Department of Communications
    American Museum of Natural History
    New York
    Tel: +1 212 496 3419

    Science contacts

    Prof Barry L McKernan
    Department of Astrophysics
    American Museum of Natural History
    New York

    Saavik K Ford
    Associate Professor
    American Museum of Natural History
    New York
    Scientists have shown how gravitational waves—invisible ripples in the fabric of space and time that propagate through the universe—might be “seen” by looking at the stars. The new model proposes that a star that oscillates at the same frequency as a gravitational wave will absorb energy from that wave and brighten, an overlooked prediction of [Albert] Einstein’s 1916 theory of general relativity. The study, which was published today in the journal Monthly Notices of the Royal Astronomical Society: Letters, contradicts previous assumptions about the behaviour of gravitational waves.

    “It’s pretty cool that a hundred years after Einstein proposed this theory, we’re still finding hidden gems,” said Barry McKernan, a research associate in the American Museum of Natural History’s Department of Astrophysics, who is also a professor at CUNY’s Borough of Manhattan Community College; a faculty member at CUNY’s Graduate Center; and a Kavli Scholar at the Kavli Institute for Theoretical Physics.

    Gravitational waves can be thought of like the sound waves emitted after an earthquake, but the source of the “tremors” in space are energetic events like supernovae (exploding stars), binary neutron stars (pairs of burned-out cores left behind when stars explode), or the mergers of black holes and neutron stars. Although scientists have long known about the existence of gravitational waves, they’ve never made direct observations but are attempting to do so through experiments on the ground and in space.

    An illustration of the gravitational waves generated by two black holes in orbit around one other. Credit: NASA. Part of the reason why detection is difficult is because the waves interact so weakly with matter. But McKernan and his colleagues from CUNY, the Harvard-Smithsonian Center for Astrophysics, the Institute for Advanced Study, and Columbia University, suggest that gravitational waves could have more of an effect on matter than previously thought.

    The new model shows that stars with oscillations—vibrations—that match the frequency of gravitational waves passing through them can resonate and absorb a large amount of energy from the ripples.

    “It’s like if you have a spring that’s vibrating at a particular frequency and you hit it at the same frequency, you’ll make the oscillation stronger,” McKernan said. “The same thing applies with gravitational waves.”

    If these stars absorb a large pulse of energy, they can be “pumped up” temporarily and made brighter than normal while they discharge the energy over time. This could provide scientists with another way to detect gravitational waves indirectly.

    “You can think of stars as bars on a xylophone—they all have a different natural oscillation frequency,” said co-author Saavik Ford, who is a research associate in the Museum’s Department of Astrophysics as well as a professor at the Borough of Manhattan Community College, CUNY; a faculty member at CUNY’s Graduate Center; and a Kavli Scholar at the Kavli Institute for Theoretical Physics.

    ‘If you have two black holes merging with each other and emitting gravitational waves at a certain frequency, you’re only going to hit one of the bars on the xylophone at a time. But because the black holes decay as they come closer together, the frequency of the gravitational waves changes and you’ll hit a sequence of notes. So you’ll likely see the big stars lighting up first followed by smaller and smaller ones.”

    The work also presents a different way to indirectly detect gravitational waves. From the perspective of a gravitational wave detector on Earth or in space, when a star at the right frequency passes in front of an energetic source such as merging black holes, the detector will see a drop in the intensity of gravitational waves measured. In other words, stars—including our own Sun—can eclipse background sources of gravitational waves.

    “You usually think of stars as being eclipsed by something, not the other way around,” McKernan said.

    The researchers will continue to study these predictions and try to determine how long it would take to observe these effects from a telescope or detector.

    See the full article here.

    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

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    See the full article here.

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  • richardmitnick 3:50 pm on September 22, 2014 Permalink | Reply
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    From Caltech: “Variability Keeps The Body In Balance” 

    Caltech Logo

    Jessica Stoller-Conrad

    Although the heart beats out a very familiar “lub-dub” pattern that speeds up or slows down as our activity increases or decreases, the pattern itself isn’t as regular as you might think. In fact, the amount of time between heartbeats can vary even at a “constant” heart rate—and that variability, doctors have found, is a good thing.


    Reduced heart rate variability (HRV) has been found to be predictive of a number of illnesses, such as congestive heart failure and inflammation. For athletes, a drop in HRV has also been linked to fatigue and overtraining. However, the underlying physiological mechanisms that control HRV—and exactly why this variation is important for good health—are still a bit of a mystery.

    By combining heart rate data from real athletes with a branch of mathematics called control theory, a collaborative team of physicians and Caltech researchers from the Division of Engineering and Applied Sciences have now devised a way to better understand the relationship between HRV and health—a step that could soon inform better monitoring technologies for athletes and medical professionals.

    The work was published in the August 19 print issue of the Proceedings of the National Academy of Sciences.

    To run smoothly, complex systems, such as computer networks, cars, and even the human body, rely upon give-and-take connections and relationships among a large number of variables; if one variable must remain stable to maintain a healthy system, another variable must be able to flex to maintain that stability. Because it would be too difficult to map each individual variable, the mathematics and software tools used in control theory allow engineers to summarize the ups and downs in a system and pinpoint the source of a possible problem.

    Researchers who study control theory are increasingly discovering that these concepts can also be extremely useful in studies of the human body. In order for a body to work optimally, it must operate in an environment of stability called homeostasis. When the body experiences stress—for example, from exercise or extreme temperatures—it can maintain a stable blood pressure and constant body temperature in part by dialing the heart rate up or down. And HRV plays an important role in maintaining this balance, says study author John Doyle, the Jean-Lou Chameau Professor of Control and Dynamical Systems, Electrical Engineering, and Bioengineering.

    “A familiar related problem is in driving,” Doyle says. “To get to a destination despite varying weather and traffic conditions, any driver—even a robotic one—will change factors such as acceleration, braking, steering, and wipers. If these factors suddenly became frozen and unchangeable while the car was still moving, it would be a nearly certain predictor that a crash was imminent. Similarly, loss of heart rate variability predicts some kind of malfunction or ‘crash,’ often before there are any other indications,” he says.

    To study how HRV helps maintain this version of “cruise control” in the human body, Doyle and his colleagues measured the heart rate, respiration rate, oxygen consumption, and carbon dioxide generation of five healthy young athletes as they completed experimental exercise routines on stationary bicycles.

    By combining the data from these experiments with standard models of the physiological control mechanisms in the human body, the researchers were able to determine the essential tradeoffs that are necessary for athletes to produce enough power to maintain an exercise workload while also maintaining the internal homeostasis of their vital signs.

    Because monitors in hospitals can already provide HRV levels and dozens of other signals and readings, the integration of such mathematical analyses of control theory into HRV monitors could, in the future, provide a way to link a drop in HRV to a more specific and treatable diagnosis. In fact, one of Doyle’s students has used an HRV application of control theory to better interpret traditional EKG signals.

    Control theory could also be incorporated into the HRV monitors used by athletes to prevent fatigue and injury from overtraining, he says.

    “Physicians who work in very data-intensive settings like the operating room or ICU are in urgent need of ways to rapidly and acutely interpret the data deluge,” says Marie Csete, MD (PhD, ’00), chief scientific officer at the Huntington Medical Research Institutes and a coauthor on the paper. “We hope this work is a first step in a larger research program that helps physicians make better use of data to care for patients.”

    “For example, the heart, lungs, and circulation must deliver sufficient oxygenated blood to the muscles and other organs while not raising blood pressure so much as to damage the brain,” Doyle says. “This is done in concert with control of blood vessel dilation in the muscles and brain, and control of breathing. As the physical demands of the exercise change, the muscles must produce fluctuating power outputs, and the heart, blood vessels, and lungs must then respond to keep blood pressure and oxygenation within narrow ranges.”

    Once these trade-offs were defined, the researchers then used control theory to analyze the exercise data and found that a healthy heart must maintain certain patterns of variability during exercise to keep this complicated system in balance. Loss of this variability is a precursor of fatigue, the stress induced by exercise. Today, some HRV monitors in the clinic can let a doctor know when variability is high or low, but they provide little in the way of an actionable diagnosis.

    Because monitors in hospitals can already provide HRV levels and dozens of other signals and readings, the integration of such mathematical analyses of control theory into HRV monitors could, in the future, provide a way to link a drop in HRV to a more specific and treatable diagnosis. In fact, one of Doyle’s students has used an HRV application of control theory to better interpret traditional EKG signals.

    See the full article here.

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
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  • richardmitnick 2:58 pm on September 22, 2014 Permalink | Reply
    Tags: , , , , , Planets   

    From CfA: “Is Pluto a Planet? The Votes Are In “ 

    Harvard Smithsonian Center for Astrophysics

    Center For Astrophysics

    September 22, 2014
    David A. Aguilar
    Director of Public Affairs
    Harvard-Smithsonian Center for Astrophysics

    Christine Pulliam
    Public Affairs Specialist
    Harvard-Smithsonian Center for Astrophysics

    What is a planet? For generations of kids the answer was easy. A big ball of rock or gas that orbited our Sun, and there were nine of them in our solar system. But then astronomers started finding more Pluto-sized objects orbiting beyond Neptune. Then they found Jupiter-sized objects circling distant stars, first by the handful and then by the hundreds. Suddenly the answer wasn’t so easy. Were all these newfound things planets?


    Since the International Astronomical Union (IAU) is in charge of naming these newly discovered worlds, they tackled the question at their 2006 meeting. They tried to come up with a definition of a planet that everyone could agree on. But the astronomers couldn’t agree. In the end, they voted and picked a definition that they thought would work.

    The current, official definition says that a planet is a celestial body that:

    is in orbit around the Sun,
    is round or nearly round, and
    has “cleared the neighborhood” around its orbit.

    But this definition baffled the public and classrooms around the country. For one thing, it only applied to planets in our solar system. What about all those exoplanets orbiting other stars? Are they planets? And Pluto was booted from the planet club and called a dwarf planet. Is a dwarf planet a small planet? Not according to the IAU. Even though a dwarf fruit tree is still a small fruit tree, and a dwarf hamster is still a small hamster.

    Eight years later, the Harvard-Smithsonian Center for Astrophysics decided to revisit the question of “what is a planet?” On September 18th, we hosted a debate among three leading experts in planetary science, each of whom presented their case as to what a planet is or isn’t. The goal: to find a definition that the eager public audience could agree on!

    Science historian Dr. Owen Gingerich, who chaired the IAU planet definition committee, presented the historical viewpoint. Dr. Gareth Williams, associate director of the Minor Planet Center, presented the IAU’s viewpoint. And Dr. Dimitar Sasselov, director of the Harvard Origins of Life Initiative, presented the exoplanet scientist’s viewpoint.

    Gingerich argued that “a planet is a culturally defined word that changes over time,” and that Pluto is a planet. Williams defended the IAU definition, which declares that Pluto is not a planet. And Sasselov defined a planet as “the smallest spherical lump of matter that formed around stars or stellar remnants,” which means Pluto is a planet.

    After these experts made their best case, the audience got to vote on what a planet is or isn’t and whether Pluto is in or out. The results are in, with no hanging chads in sight.

    According to the audience, Sasselov’s definition won the day, and Pluto IS a planet.

    The video of the debate and audience vote can be seen on YouTube at [Or, you can watch it right here.]

    Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

    See the full article here.

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

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  • richardmitnick 2:33 pm on September 22, 2014 Permalink | Reply
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    From New Scientist: Was Aristotle the inventor of science? 


    New Scientist

    22 September 2014
    Nicolas Rasmussen

    The ancient Greek philosopher deserves our homage, and Armand Marie Leroi delivers it in his edifying and excellent book.


    EVERY generation of biologist must rediscover Aristotle for itself, to paraphrase Armand Leroi in a BBC documentary, Aristotle’s Lagoon.


    Four years on, Leroi, a biologist at Imperial College London, has written a book with nearly the same name. The full fruits of the author’s decade of immersion in Aristotle, it represents both Leroi’s personal discovery of the ancient Greek and a quest to recover his science for biologists today.

    Once a highway, this path has been trodden by only a few life scientists in four generations. And in taking it, the author retraces Aristotle’s footsteps to Kalloni lagoon on the island of Lesbos, where the philosopher studied nature, providing charming vignettes from his visits there.

    There is a serious purpose, too. Aware that scientists tend to distort past thinkers by imposing present conceptions and values on them, Leroi argues that today’s biologists can think like Aristotle because he forged their basic concepts, and because nature shows us the same phenomena. But to best understand Aristotle, a biologist must see what he saw in Lesbos.

    The Lagoon is an intellectual homage – an admiring, deeply researched and considered reconstruction of Aristotle’s thinking about living things. The effort to get inside his head seems driven by a heartfelt sympathy, a sense of wonder about life on Earth shared across 2300 years, and by the modern scientist’s urge to give credit where credit is due.

    And for Leroi, Aristotle deserves credit for nothing less than inventing biology – perhaps even science. Earlier philosophers, like his teacher Plato, deduced stories about the fundamental causes of natural phenomena from . But physicians in the empirical tradition, to which Aristotle was exposed by his physician father, learned how to predict the course of disease from observation. Aristotle was arguably the first to attempt an evidence-based natural philosophy (or “science”), melding empiricism with logic.

    The book is structured with major sections corresponding to topic areas in Aristotle’s work, such as taxonomy, nutrition, or cosmology, each broken into half a dozen short chapters, often containing Leroi’s Lesbos experiences to make the natural phenomena accessible and intriguing. For example, we learn about the vigorous argument he observed among taverna patrons over whether sardelles and papalinas are really the same fish (they look similar but taste different, and live in different waters). This example of the classification problem nicely introduces Leroi’s discussion of Aristotle’s taxonomic system.

    The prose is so lively, the thinking so lucid, and the use of such devices so artful, one might not notice it all adds up to a 500-page systematic analysis of a massive, dry, sometime jumbled philosophical corpus from a profoundly alien society. That many readers will come away entertained, and with even a slightly better understanding of Aristotle would be a major literary feat even if the book did not offer significant original contributions.

    But it does. Take Leroi’s account of Aristotle’s concept of soul, psyche. It is well thought through, closely argued on textual evidence, and innovative. As my wonderful teacher, classicist Arthur Adkins, said, psyche was “for Greeks only the difference between a dead rabbit and a live rabbit”. In other words, to explain psyche is to explain life.

    Leroi shows that Aristotle was no vitalist, in the sense that he required nothing more than ordinary matter and its properties to explain life. He understands that for Aristotle the soul was its form (eidos, which can also mean species), the order of a creature’s material – a pattern of activity constituting its life.

    Organisation as life is a view remarkably close to modern biology: for Leroi, biology is all about mapping the body’s regular material transformations. I am sympathetic to his effort to credit Aristotle with something very like modern biological insights, and indeed, I find Leroi’s arguments that Aristotle invented the concepts of metabolic networks and feedback control plausible.

    Leroi offers another innovation in finding a “dual-inheritance” theory in Aristotle’s writing, resolving the conundrum of form (eidos again) coming only from the father and the undeniable phenomenon that children resemble both parents. Thus, for Aristotle the movements of the generative fluids of female and male can, without major self-contradiction, transmit details of form (like Socrates’s snub nose) less significant than those defining the species, imparted by the father.

    Elsewhere in Leroi’s discussion of reproduction, we read: “What is the immediate source of the design that we see in living things? It is the information that they inherit from their parents.” Or, to paraphrase the BBC documentary again, Aristotle taught that material self-assembles into organisms only with the help of information.

    Here Leroi goes too far. Despite acknowledging the danger of anachronism, he is actually likening the Aristotelian concept of eidos to modern biology’s notion of genetic information. Biology’s concept of information is less than a century old, deriving from computer science. Psyche, the realisation of a creature’s eidos, was an activity, more like an oscillation than a formula or code.

    Furthermore, the Greeks did not have the problem vitalism and materialism both answer. Our premise that ordinary matter must be utterly passive stems from Reformation Christianity. Without this expectation, the difference between dead and alive is not as radical as we perceive. For ancient Greeks, all matter was dynamic, living matter only more so.

    From this perspective we can see why Aristotle accepted spontaneous generation without anxiety: putrefying matter, already seething with change, could accidentally fall into self-perpetuating patterns of activity and thus spin off organisms –maggots in corpses or oysters in mud. Insufficiently attuned to the animism (or more accurately, hylozoism) of the Greeks, Leroi unfairly scolds Aristotle for inconsistency with his own metaphysics and his mature theory of reproduction.

    Such quibbles are not meant to detract from this marvellous book. Leroi’s Aristotle is a fit hero for the biological century, and The Lagoon is a work as important to a historian and philosopher of science as it is informative to a biologist and entertaining to the general reader. As compelling as Stephen Jay Gould’s best work, it will long outlast most nature writing of recent years.

    Nicolas Rasmussen is professor of history and philosophy of science at the University of New South Wales, Sydney, Australia

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