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For the reaction below, the equilibrium constant is Kc = 3.2×
10−10 at 25 °C.
Pb(s) + 2 Cr3+(aq) ⇌ Pb2+(aq) + 2 Cr2+(aq)
Excess Pb(s) is added to a solution for which the initial concentration of Cr3+(aq) is 2.0 mol L−1. What are the equilibrium concentrations of Pb2+ and Cr2+ ?
Enter values accurate to 2 significant figures. Do not include units.
[Pb2+]eq = (0%) mol L−1
[Cr2+]eq = (0%) mol L−1
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Experiment generates THz radiation 20,000 times brighter than anyone else
Gwyn Williams, JLab's FEL Basic Research Program manager, led a multi-lab experiment that generated nearly 20 watts of terahertz radiation - a world record.
An experiment conducted by the Department of Energy's Jefferson Lab generates THz radiation 20,000 times brighter than anyone else; breakthrough lights way for application development
An experiment conducted with Jefferson Lab's Free-Electron Laser (FEL) has shown how to make a highly useful form of light - called terahertz radiation - 20,000 times brighter than ever before. Jefferson Lab is a Department of Energy laboratory located in Newport News, Virginia.
The name "terahertz radiation" derives from the frequency of the radiation - of the order of one trillion oscillations per second. The corresponding wavelength is of the order of tenths of a millimeter. Terahertz radiation is thus located in the spectrum of electromagnetic radiation between the upper end of the microwave range (mm wavelength) and the far infrared (hundredths of mm). Terahertz radiation is non-ionizing and shares with microwaves the capability to penetrate a wide variety of non-conducting materials.
Gwyn Williams, JLab's Free-Electron Laser Basic Research Program manager, conceived and led the multi-laboratory team conducting the experiment, which took place during November 2001. The results were published in the Nov. 14, 2002, issue of the international science journal Nature.
Among the prospective benefits, the breakthrough lights the way toward better detection of concealed weapons, hidden explosives and land mines; improved medical imaging and more productive study of cell dynamics and genes; real-time "fingerprinting" of chemical and biological terror materials in envelopes, packages or air; better characterization of semiconductors; and widening the frequency bands available for wireless communication.
To produce, for the first time ever, intense terahertz radiation, researchers from JLab and two other Department of Energy laboratories — Brookhaven National Lab and Lawrence Berkeley National Lab — made use of the fact that the driver linac of JLab's Free-Electron Laser is made up of intense electron bunches that are a few tenths of a millimeter long, i.e. comparable to the wavelength of terahertz radiation. Sending any energetic electron beam through a magnetic field makes the beam emit radiation, so-called synchrotron radiation, a process that is greatly enhanced (coherent synchrotron radiation) when the length of the electron bunches is as short or shorter than the radiation wavelength of interest.
Terahertz radiation has much scientific potential.
Researchers paving way for T-ray applications
For over a decade, scientists worldwide have been pressing the study of light in the terahertz region and looking for better ways to generate and use it. The light is also referred to occasionally as T-rays, T-light or T-lux. An August 16 Science magazine article, "Revealing the Invisible," reported that "much research is being directed toward the development of T-ray sources and detectors, particularly for applications in medical imaging and security scanning systems." Xi-Cheng Zhang, a T-ray expert at Rensselaer Polytechnic Institute, predicts that terahertz light will be "the future 'killer application' ... in biomedicine."
Picometrix Tochigi Nikon Corporation and Teraview — a Cambridge, England, start-up associated with Toshiba — have begun commercializing low-power terahertz systems. A few hospitals are already testing comparatively dim sources of terahertz light for detecting skin cancer.
Overall, though, terahertz light still constitutes a gap in the science of light and energy. It inhabits a region of the electromagnetic spectrum not that well understood. Now that a way to generate it at high power has been demonstrated, terahertz light can potentially extend and add widely to the wave-based technologies that have defined the last 150 years: from the telegraph, radio and X-rays to computers, and cell phones.
Up to this point, no other method of generating terahertz waves had yielded more than two-thousandths of a watt in power. But Williams and his colleagues extracted nearly 20 watts — some 20,000 times more. "Think of a candle and then think of a floodlight," says Williams.
Left to right: Gwyn Williams and his two JLab co-authors for the Nature paper — George Neil and Kevin Jordan — stop for a quick photo in the FEL vault.
But no matter how bright they are, terahertz light rays can't penetrate metal or water. So they can't be used to inspect cargo containers on arriving ships or to diagnose conditions deep inside the human body. "Nevertheless," says Williams, "the growing awareness of terahertz light's usefulness is like what happened a century ago with X-rays — only terahertz light will have a much wider range of applications. The task now will be to develop those uses."
Bringing 10-year-old idea to fruition
About 10 years ago Williams wrote a paper proposing a method for generating large amounts of terahertz light. In the mid-90s he started following the development of JLab's Free-Electron Laser. Williams came to Jefferson Lab from Brookhaven National Lab in the spring of 2000; he actively began pursuing his experiment last June, when he drove a van to Brookhaven to bring back a spectrometer on loan from his old laboratory. Kevin Jordan and George Neil, both JLab staff, soon had it installed and proof-of-principle experiments took place. The final run, with a better spectrometer and detector, took place in early November 2001 and included Larry Carr from Brookhaven, and Michael Martin and Wayne McKinney from Lawrence Berkeley National Lab.
"We didn't create something new," Williams explains. "The terahertz light had always been there inside of the FEL's vacuum-sealed beam pipe. We just figured out how to open the pipe, put in a window to let the light out, and how to measure it." Williams is looking forward to performing proof-of-principle experiments of the capabilities of THz light with the upgraded FEL and a newly designed section of FEL beam pipe that should allow even more of the light out.
Williams and his collaborators presented their results at the First International Conference on Terahertz Radiation in December of 2001, and shortly thereafter he wrote the experiment up and submitted it to Nature. Due to the novel arena, it took some time before the paper was accepted, but it finally was.
While the U.S. Navy funded the FEL's construction to investigate the science and technology of high-power laser beams whose precise wavelength can be selected, the funding to run Williams' and his colleagues' experiment was from the Commonwealth of Virginia.
Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE Applied Technologies, manages and operates the Thomas Jefferson National Accelerator Facility, or Jefferson Lab, for the U.S. Department of Energy's Office of Science.DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov. | <urn:uuid:da162bde-8335-46e0-98b8-e12244492a69> | 3.359375 | 1,547 | News (Org.) | Science & Tech. | 36.25384 | 95,513,701 |
Hallo, this time we’ll talk about Latest Technology News from headline Scientists seize first picture of new child planet. Need to know what sort of evaluations? right here we now have summarized for you.
Newest Information : Scientists seize first picture of new child planet
Scientists on the Max Planck Institute for Astronomy in Germany snapped the spectacular image of a planet forming across the star PDS 70 from the Very Massive Telescope (VLT) in Chile.
Operated by the European Southern Observatory (ESO), the telescope has one of the subtle planet-hunting devices in existence, often called SPHERE.
Recognized in full as Spectro-Polarimetric Excessive-contrast Exoplanet REsearch, SPHERE made the primary strong detection of a new child planet by measuring the totally different wavelengths of sunshine by means of its environment.
The photographs that the group captured present the planet as a vibrant level beside the black filter protecting the star on the centre of the picture.
Named PDS 70b, the planet is orbiting the central star at a distance of round three billion kilometres – much like the place Uranus is in our galaxy.
In accordance with the researchers’ evaluation, the planet is a gasoline big which is much more large than Jupiter, and has a floor temperature of round 1000C.
The filter – formally often called a coronagraph – blocks the sunshine from the central star and permits astronomers to detect the a lot fainter planet and the discs surrounding the star.
“These discs round younger stars are the birthplaces of planets, however to date solely a handful of observations have detected hints of child planets in them,” mentioned Dr Miriam Keppler.
“The issue is that till now, most of those planet candidates may simply have been options within the disc,” defined Dr Keppler, who lead the group behind the invention of the planet.
The invention was introduced in two papers to be revealed within the Astronomy & Astrophysics journal.
Each research used the hi-tech capabilities of ESO’s SPHERE instrument, which makes use of a method referred to as high-contrast imaging to filter out the indicators of planets from stars.
Thomas Henning, director on the Max Planck Institute for Astronomy and chief of each of the groups, mentioned: “After greater than a decade of monumental efforts to construct this high-tech machine, now SPHERE allows us to reap the harvest with the invention of child planets!”
Overview : Scientists seize first picture of new child planet
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Be certain that to maintain up-to-date on the latest techno news introduced by EastSpace Network. See you on one other Information replace. | <urn:uuid:830dd507-5c6a-447c-8c88-4400c4676996> | 2.78125 | 597 | News Article | Science & Tech. | 35.821989 | 95,513,702 |
The extension of bioenergy as the cultivation of maize leads to problems to biological diversity in agrarian regions. With different accompanying measures, such as the conservation of near-nature areas, however, these effects could be partly reduced. Photo: Jan Engel/ FSU Jena
2009, are again used for intensive agricultural production. Ecologically, it would make more sense, however, to take at least a portion of the area in the future from agricultural use and waste land and to develop field margins. How important are such extensive forms of agriculture for conservation had shown ecologists, for example, with reference to amphibians in Romania's Transylvania. (http://www.ufz.de/index.php?en=21768)
Photo: Tilo Arnhold/UFZ
These tendencies in today's intensive agriculture can be partly counteracted by the preservation of remaining nearly natural areas and field margins. However, it was also shown that both the extent of the resulting risks and the effectiveness of the counteracting conservation measures depend upon the structure of the particular agricultural landscape and the size of the fields. The larger and more homogeneous the landscape, the more important is the conservation of highly diverse nearly natural areas and field margins.The Eurasian skylark is the most common open land field bird in central Europe. The intensification of agriculture in recent years has resulted in a decline of around one third in their numbers. "The Eurasian skylark is a type of indicator for the ecological state of many regions used for agriculture, because they have settled in different areas of this intensively utilised open land, bred over many months on the ground in fields and fed on mainly insects and, additionally, the seeds of wild herbs and grains found there", explains Jan Engel, the first author of the UFZ-study, who is working at the University of Jena in the meantime. "This bird species is representative for important areas of the agrarian ecosystem. An improvement in the habitat quality for the skylark would therefore also support vegetation, insects and other ground-breeding bird species". In addition to the Eurasian skylark (Alauda arvensis), the researchers are currently investigating the effects on other field birds such as the Yellow wagtail (Motacilla flava) and the Corn bunting (Emberiza calandra) with their model in order to be able to make more extensive statements in future.
Tilo Arnhold | UFZ News
Further reports about: > Biodiversity > Ecological Impact > Environmental Research > Eurasian > Helmholtz > Production line > Reduced > UFZ > agricultural land > bioenergy > bird population > bird species > computer model > conservation measures > energy production > environmental risk > natural areas > natural resource > nature conservation > waste material > water resource
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
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A lithoautotroph (or chemolithoautotroph) is a microbe which derives energy from reduced compounds of mineral origin. Lithoautotrophs are a type of lithotrophs with autotrophic metabolic pathways. Lithoautotrophs are exclusively microbes; macrofauna do not possess the capability to use mineral sources of energy. For lithoautotrophic bacteria, only inorganic molecules can be used as energy sources. Most lithoautotrophs belong to the domain Bacteria. The term "Lithotroph" is created from the terms 'lithos' (rock) and 'troph' (consumer); literally, it may be read "eaters of rock". Many lithoautotrophs are extremophiles, but this is not universally so.
Lithoautotrophs are extremely specific in using their energy source. Thus, despite the diversity in using inorganic molecules in order to obtain energy that lithoautotrophs exhibit as a group, one particular lithoautotroph would use only one type of inorganic molecules to get its energy.
Lithoautotrophs participate in many geological processes, such as the weathering of parent material (bedrock) to form soil, as well as biogeochemical cycling of sulfur, potassium, and other elements. They may be present in the deep terrestrial subsurface (they have been found well over 3 km below the surface of the planet), in soils, and in endolith communities. As they are responsible for the liberation of many crucial nutrients, and participate in the formation of soil, lithoautotrophs play a crucial role in the maintenance of life on Earth.
Acid mine drainage
Lithoautotrophic microbial consortia are responsible for the phenomenon known as acid mine drainage, whereby energy-rich pyrite present in mine tailing heaps and in exposed rock faces is metabolized to form sulfites, which form potentially corrosive sulfuric acid when dissolved in water and exposed to aerial oxygen. Acid mine drainage drastically alters the acidity and chemistry of groundwater and streams, and may endanger plant and animal populations. Activity similar to acid mine drainage, but on a much lower scale, is also found in natural conditions such as the rocky beds of glaciers, in soil and talus, and in the deep subsurface. | <urn:uuid:b9b1da60-ff3b-49a0-a783-59a72aa7689a> | 3.46875 | 490 | Knowledge Article | Science & Tech. | 14.278121 | 95,513,717 |
Fixed values are called “Literals”.
Variable values are called “Variables”.
The most important rules for the writing fixed values are:
Numbers are written with or without decimals:
<p id="demo"></p> <script> document.getElementById("demo").innerHTML = 10.50; </script> | <urn:uuid:523e7e97-cba8-4e86-99e9-68496f6eec32> | 2.609375 | 78 | Truncated | Software Dev. | 47.071846 | 95,513,743 |
As solar power becomes increasingly popular, there's one issue standing in the way of its widespread adoption: space. Erecting enough solar panels to effectively offset the use of fossil fuel-based energies requires a lot of sunlit space, and that often gets in the way of other necessary developments—in rural areas, solar farms can displace food farms, and in urban areas, the space is either already taken by buildings or needs to be reserved for more.
Creative solutions to this problem are beginning to pop up, such as solar fields that double as farms for shade-happy agriculture, panels that look like normal roof tiles, floating solar farms that sit atop the ocean or other bodies of water, or, most recently, a solar paneled highway.
Built in Jinan, the capital of China’s Shandong Province, the solar panel highway stretches one kilometer (.62 miles) and contains over 10,000 photovoltaic panels. The panels convert sunlight into electricity just like any other solar panels and functions just like a normal road, if not better—the paneled road is said to have safety standards that surpass that of traditional asphalt highways. The highway can handle 10 times more pressure than a normal asphalt road and will generate 1 million kWH of electricity a year.
The highway is built with transparent concrete with electromagnetic induction coils installed underneath. In addition to collecting sunlight and converting it into electricity, the road also allows electric cars to recharge wirelessly as they drive. Additionally, the energy collected by the panels can be used to warm the road in the winter, thus melting the snow and making it safer to drive.
On top of all that, the panels contain sensors that will collect data on the use of the road, which will help inform the future use of this highway as well as any others that may be installed around the world.
The road "charges" into future: the 1-kilometer solar highway has three layers including translucent concrete on top, silicon panels in the middle, and insulation at bottom. Next plan is to charge electric vehicles traveling above it https://t.co/cHRIDWue0w pic.twitter.com/NWg0Err3tY— China Xinhua News (@XHNews) December 29, 2017
The project in China defies nay-sayers, who have said while using that already-exposed and open space for solar paneling is a good idea, it's impractical in practice—too expensive, not able to collect enough power to make it worthwhile, and ultimately not safe enough (though China's roadway has disproved this last point).
The other points may be true—the road in China cost much more than a normal highway and some say this method collects 20 percent less energy than standard rooftop panels—but for solar-ambitious China, it's worth the cost. China became the world’s top solar-energy producer 2016 by upping its photovoltaic capacity to 78 gigawatts. It’s aiming for 105 by 2020. The Chinese city Huainan also operates the world’s biggest floating solar farm, which will eventually power up to 94,000 homes.
Though China claims this is the "world's first solar highway," France made the same claim with a highway of similar length in 2016. Before that, the Netherlands laid a bike path embedded with solar panels in 2014. No matter who was first, China certainly won't be the last. An American company, Solar Roadways, raised over $2 million to launch a pilot program in Sandpoint, Idaho, which should come to fruition soon.
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Using the Subaru Telescope, researchers at the Special Astrophysical Observatory in Russia and Kyoto University in Japan have found evidence that enigmatic objects in nearby galaxies - called ultra-luminous X-ray sources (ULXs) - exhibit strong outflows that are created as matter falls onto their black holes at unexpectedly high rates.
The strong outflows suggest that the black holes in these ULXs must be much smaller than expected. Curiously, these objects appear to be "cousins" of SS 433, one of the most exotic objects in our own Milky Way Galaxy.
Multi-color optical image around the ULX "X-1" (indicated by the arrow) in the dwarf galaxy Holmberg II, is located in the direction of the constellation Ursa Major, at a distance of 11 million light-years. The image size corresponds to 1,100 × 900 light-years at the galaxy. The red color represents spectral line emission from hydrogen atoms.
Credit: Special Astrophysical Observatory/Hubble Space Telescope
The team's observations help shed light on the nature of ULXs, and impact our understanding of how supermassive black holes in galactic centers are formed and how matter rapidly falls onto those black holes.
X-ray observations of nearby galaxies have revealed these exceptionally luminous sources at off-nuclear positions that radiate about million times higher power than the Sun. The origins of ULXs have been a subject of heated debate for a long time.
The basic idea is that a ULX is a close binary system consisting of a black hole and a star. As matter from the star falls onto the black hole, an accretion disk forms around the black hole. As the gravitational energy of the material is released, the innermost part of the disk is heated up to a temperature higher than 10 million degrees, which causes it to emit strong X-rays.
The unsolved key question about these objects asks: what is the mass of the black hole in these bright objects? ULXs are typically more than a hundred times more luminous than known black hole binaries in the Milky Way, whose black hole masses are at most 20 times the mass of the Sun.
There are two different black hole scenarios proposed to explain these objects: (1) they contain very "big" black holes that could be more than a thousand times more massive than the Sun (Note 1), or (2) they are relatively small black holes, "little monsters" with masses no more than a hundred times that of the Sun, that shine at luminosities exceeding theoretical limits for standard accretion (called "supercritical (or super-Eddington) accretion," Note 2). Such supercritical accretion is expected to produce powerful outflow in a form of a dense disk wind.
To understand which scenario explains the observed ULXs researchers observed four objects: Holmberg II X-1, Holmberg IX X-1, NGC 4559 X-7, NGC 5204 X-1, and took high-quality spectra with the FOCAS instrument on Subaru Telescope for four nights. Image 1 shows an optical multi-color image toward Holmberg II X-1 as observed with Hubble Space Telescope. The object X-1, indicated by the arrow, is surrounded by a nebula (colored in red), which is most likely the gas heated by strong radiation from the ULX.
The team discovered a prominent feature in the optical spectra of all the ULXs observed. It is a broad emission line from helium ions, which indicates the presence of gas heated to temperatures of several tens of thousands of degrees in the system. In addition, they found that the width of the hydrogen line, which is emitted from cooler gas (with a temperature of about 10,000 K), is broader than the helium line. The width of a spectral line reflects velocity dispersion of the gas and shows up due to the Doppler effect caused by a distribution of the velocities of gas molecules. These findings suggest that the gas must be accelerated outward as a wind from either the disk or the companion star and that it is cooling down as it escapes.
Distant ULXs and a Similar Mysterious Object in the Milky Way:
The activity of these ULXs in distant galaxies is very similar to a mysterious object in our own Milky Way. The team noticed that the same line features are also observed at SS 433, a close binary consisting of an A-type star and most probably a black hole with a mass less than 10 times that of the Sun. SS 433 is famous for its persistent jets with a velocity of 0.26 times the speed of light. It is the only confirmed system that shows supercritical accretion (that is, an excessive amount of accretion that results in a very powerful outflow). By contrast, such features have not been observed from "normal" black hole X-ray binaries in the Milky Way where sub-critical accretion takes place.
After carefully examining several possibilities, the team concluded that huge amounts of gas are rapidly falling onto "little monster" black holes in each of these ULXs, which produces a dense disk wind flowing away from the supercritical accretion disk. They suggest that "bona-fide" ULXs with luminosities of about million times that of the Sun must belong to a homogeneous class of objects, and SS 433 is an extreme case of the same population. In these, even though the black hole is small, very luminous X-ray radiation is emitted as the surrounding gas falls onto the disk at a huge rate.
Image 3 is a schematic view of the ULXs (upper side) and SS 433 (lower side). If the system is observed from a vertical direction, it's clear that the central part of the accretion disk emits intense X-rays. If SS 433 were observed in the same direction, it would be recognized as the brightest X-ray source in the Milky Way. In reality, since we are looking at SS 433 almost along the disk plane, our line-of-sight view towards the inner disk is blocked by the outer disk. The accretion rate is inferred to be much larger in SS 433 than in the ULXs, which could explain the presence of persistent jets in SS 433.
Such "supercritical accretion" is thought to be a possible mechanism in the formation of supermassive black holes at galactic centers in very short time periods (which are observed very early in cosmic time). The discovery of these phenomena in the nearby universe has significant impacts on our understanding of how supermassive black holes are formed and how matter rapidly falls onto them.
There are still some remaining questions: What are the typical mass ranges of the black holes in ULXs? In what conditions can steady baryonic jets as observed in SS 433 be produced? Dr. Yoshihiro Ueda, a core member of the team, expresses his enthusiasm for future research in this area. "We would like to tackle these unresolved problems by using the new X-ray observations by ASTRO-H, planned to be launched early next year, and by more sensitive future X-ray satellites, together with multi-wavelength observations of ULXs and SS 433," he said.
This work has been published online in Nature Physics on 2015 June 1 (Fabrika et al. 2015, "Supercritical Accretion Discs in Ultraluminous X-ray Sources and SS 433", 10.1038/nphys3348). The research was supported by the Japan Society for the Promotion of Science's KAKENHI Grant number 26400228.
Sergei Fabrika (Special Astrophysical Observatory, Russia; Kazan Federal University, Russia)
Yoshihiro Ueda (Department of Astronomy, Kyoto University, Japan)
Alexander Vinokurov (Special Astrophysical Observatory, Russia)
Olga Sholukhova (Special Astrophysical Observatory, Russia)
Megumi Shidatsu (Department of Astronomy, Kyoto University, Japan)
1. Generally, black holes with masses between about 100 and about 100,000 times that of the Sun are called "intermediate-mass black holes," although there is no strict definition for the mass range.
2. In a spherically symmetric case, matter cannot fall onto a central object when the radiation pressure exceeds the gravity. This luminosity is called the Eddington limit, which is proportional to the mass of the central object. When matter is accreted at rates higher than that corresponding to the Eddington limit, it is called "supercritical (or super-Eddington) accretion." In the case of non-spherical geometry, such as disk accretion, supercritical accretion may happen.
Associate Professor, Kyoto University
Public Information Officer/Scientist, Subaru Telescope, National Astronomical Observatory of Japan
Hideaki Fujiwara | EurekAlert!
Computer model predicts how fracturing metallic glass releases energy at the atomic level
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A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
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Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
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After months of almost but not quite breaking away from Antarctica, a trillion-ton chunk of the Larsen C Ice Shelf finally detached itself in July and drifted off into the Southern Ocean. As it so happens, this chilly divorce may have been a good thing, as it’s exposed a brand-new, never-before-seen ecosystem hiding just beneath the waves, IFL Science reports.
It’s never ideal when ice shelves disintegrate. They expose the glaciers behind them to open waters, where they can fall in and push up sea levels.
However, researchers working at various institutions, from the British Antarctic Survey (BAS), Germany’s Alfred Wegener Institute for Polar and Marine Research, and the Korea Polar Research Institute have all said that they intend to conduct biological expeditions to the exposed area.
As reported by Nature News, as soon as it’s safe to sail there, all three will venture into the area. The earliest anyone will reach it will be 2019 in what will essentially be an exhilarating zoological race to the finish.
This area has been shielded from the surface for as long as 120,000 years. Every time an ice shelf breaks off, or anytime anyone is daring enough to dive underneath the ice cover itself, new species are discovered – and this time is likely to be no different.
Additionally, species that normally can’t live in such harsh conditions will have found that, since being exposed to sunlight, the zone is far more habitable than it used to be. With sunlight, you get photosynthesizing plankton. When they die, their nutrients fall to the seafloor – food for plenty of aquatic lifeforms there.
“I cannot imagine a more dramatic shift in environmental conditions in any ecosystem on Earth,” Julian Gutt, a marine ecologist at the Alfred Wegener Institute, told Nature.
If the area exposed by the breakaway iceberg – known as A68 – isn’t already a treasure trove of life, it soon will be. That’s why the BAS and others have worked hard to make sure it’s designated as a Special Area of Scientific Study.
“An international agreement is now in place to give special protection to the area of ocean left exposed when one of the largest icebergs ever recorded broke free from the Larsen C Ice Shelf in July this year,” a recent BAS press release reads.
Ultimately, as A68 continues to move northwards, “it will leave behind a 5,818-square kilometer [2,246 square miles] area of seabed exposed to open marine conditions.”
WN.com, Jim Berrie
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A Paperback edition by Robert M. M. Crawford in English (Dec 1, 2013)
$72.84 + FREE delivery
Short Description: The Arctic Tundra and adjacent Boreal Forest or Taiga support the most cold-adapted flora and fauna on Earth. The evolutionary capacity of both plants and animals to adapt to these... Read more
The Arctic Tundra and adjacent Boreal Forest or Taiga support the most cold-adapted flora and fauna on Earth. The evolutionary capacity of both plants and animals to adapt to these thermally limiting conditions has always attracted biological investigation and is a central theme of this book. How the polar biota will adapt to a warmer world is creating significant and renewed interest in this habitat. The Arctic has always been subject to climatic fluctuation and the polar biota has successfully adapted to these changes throughout its evolutionary history. Whether or not climatic warming will allow the Boreal Forest to advance onto the treeless Tundra is one of the most tantalizing questions that can be asked today in relation to terrestrial polar biology.
Tundra-Taiga Biology provides a circum-polar perspective of adaptation to low temperatures and short growing seasons, together with a history of climatic variation as it has affected the evolution of terrestrial life in the Tundra and the adjacent forested Taiga. It will appeal to researchers new to the field and to the many students, professional ecologists and conservation practitioners requiring a concise but authoritative overview of the biome. Its accessibility also makes it suitable for undergraduate and graduate students taking courses in tundra, taiga, and arctic ecology.
Tundra-Taiga Biology Paperback edition by Robert M. M. Crawford
- Robert M. M. Crawford
- Oxford University Press
- Publication date
- Dec 1, 2013
- Product dimensions
- 190 x 246 x 13mm
1. Arctic climate history ; 2. The Holocene at high latitudes ; 3. Human arrival in the Arctic ; 4. Tundra diversity ; 5. Taiga and bog ; 6. Arctic survival in mammals and birds ; 7. Plant survival in cold habitats ; 8. Demography and reproduction ; 9. Evolution in the Arctic ; 10. Disturbance, pollution, conservation, and the future | <urn:uuid:5e231d9f-d95d-4fb5-81fa-e4088ec6cbea> | 3.0625 | 468 | Product Page | Science & Tech. | 40.596744 | 95,513,806 |
+44 1803 865913
By: John AH Benzie(Author)
368 pages, 234 plates
The genus Daphnia is one of the most widely known groups of the freshwater zooplankton. Member species are used as fundamental models in teaching biology and are widely used as test organisms in toxicology. Despite this, the taxonomy of the group remains confused. The status of the most common taxa has been the subject of debate for most of this century. A considerable effort made over the last twenty years in the molecular genetic analysis of extensive collections made over a range of geographical scales is now bearing fruit for the North American faunas, and is being extended to other regions. The present work has focussed largely on published material in order to synthesise the present state of affairs, and provide a tool to assist the collection of more useful information for the continuing revision of the genus.
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Monday, November 22, 2010
Water takes forbidden form
With at least fifteen different crystal forms, two different disordered solid phases (glasses), and perhaps two different liquid states, water is a prodigious shape-shifter. But Valeria Molinero and colleagues at the University of Utah, US now claim that water has still more tricks up its sleeve. They say that, when water is confined between two flat plates just 8.5 Angstroms apart - room enough for just two molecular layers - it can adopt a quasicrystalline state which appears to have a 'forbidden' twelve-fold symmetry.
Although there have been speculations that water might adopt such a solid form, there has previously been no firm evidence that it might exist. What's more, all earlier quasicrystals have been mixtures of two or more components, making this the first to be composed of just one. So far, however, it's just a prediction based on computer simulations - the Utah group hasn't observed quasicrystalline water experimentally.
Quasicrystals were first discovered in 1984 in an alloy of manganese and aluminium. Like crystals, they generate x-ray diffraction patterns with symmetrically arranged bright spots, but with symmetries - five-, ten- and twelve-fold - that can't be produced by any regular, orderly packing of constituent particles. Instead, quasicrystals are not perfectly periodic: they contain local atomic arrangements with these forbidden symmetries, but which do not repeat exactly.
Water seems a good candidate for making an ice-like quasicrystal, because hydrogen bonding between the molecules favours the formation of pentagonal rings.
Molinero and colleagues simulated water between the two plates at pressures of up to 5000 atmospheres: the pressure promotes pentagonal rings rather than the hexagonal rings of regular ice, because they are more compact. The researchers found one crystal phase made up of pentagons linked with four-fold symmetry, and another phase composed of both pentagons and hexagons, with twelvefold quasi-symmetry. Hideki Tanaka of Okayama University in Japan, a specialist in simulations of water and ice, says that the findings are 'of significant interest', although he adds that he's not convinced it will prove possible to observe it experimentally.
Molinero admits that the conditions of the simulations are hard to create experimentally, but adds the researchers have also found that the quasicrystal state can be stabilised without applying pressure, by tuning the strength of the water-surface interaction. So it might conceivably be made by depositing a thin film of water onto a single flat surface. 'Our holy grail is vapour deposition of the quasicrystal,' she says. 'But I expect it will take us a while, or a stroke of good luck, to be able to predict the surfaces and temperatures needed for that.
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este es un trabajo ke hice para quimica general... algo ke todos hicimos hahaahhah y weno.... me dijeroooon, ke debia postiarloooo NO SE KE... | <urn:uuid:5e81a1be-e5bd-48af-a5f7-7c22d47b6fa2> | 3.34375 | 752 | Personal Blog | Science & Tech. | 35.875039 | 95,513,811 |
Metabolism (//, from Greek: μεταβολή metabolē, "change") is the set of life-sustaining chemical transformations within the cells of organisms. The three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells, in which case the set of reactions within the cells is called intermediary metabolism or intermediate metabolism.
Metabolism is usually divided into two categories: catabolism, the breaking down of organic matter for example, the breaking down of glucose to pyruvate, by cellular respiration, and anabolism, the building up of components of cells such as proteins and nucleic acids. Usually, breaking down releases energy and building up consumes energy.
The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy that will not occur by themselves, by coupling them to spontaneous reactions that release energy. Enzymes act as catalysts that allow the reactions to proceed more rapidly. Enzymes also allow the regulation of metabolic pathways in response to changes in the cell's environment or to signals from other cells.
The metabolic system of a particular organism determines which substances it will find nutritious and which poisonous. For example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the metabolic rate, influences how much food an organism will require, and also affects how it is able to obtain that food.
A striking feature of metabolism is the similarity of the basic metabolic pathways and components between even vastly different species. For example, the set of carboxylic acids that are best known as the intermediates in the citric acid cycle are present in all known organisms, being found in species as diverse as the unicellular bacterium Escherichia coli and huge multicellular organisms like elephants. These striking similarities in metabolic pathways are likely due to their early appearance in evolutionary history, and their retention because of their efficacy.
Most of the structures that make up animals, plants and microbes are made from three basic classes of molecule: amino acids, carbohydrates and lipids (often called fats). As these molecules are vital for life, metabolic reactions either focus on making these molecules during the construction of cells and tissues, or by breaking them down and using them as a source of energy, by their digestion. These biochemicals can be joined together to make polymers such as DNA and proteins, essential macromolecules of life.
Proteins are made of amino acids arranged in a linear chain joined together by peptide bonds. Many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, a system of scaffolding that maintains the cell shape. Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Amino acids also contribute to cellular energy metabolism by providing a carbon source for entry into the citric acid cycle (tricarboxylic acid cycle), especially when a primary source of energy, such as glucose, is scarce, or when cells undergo metabolic stress. | <urn:uuid:1c977850-0df0-4a65-a9d2-1ecfa404d04e> | 3.5625 | 773 | Knowledge Article | Science & Tech. | 15.491198 | 95,513,849 |
The gas to be analyzed (Helium or Argon) is passed through a detection chamber and is submitted to an intense electromagnetic field created between two electrodes by a high frequency generator.
Under these conditions, it becomes the center of a luminous phenomenon, the characteristics of which are modified by any foreign elements in the initial gas passing through the chamber. An interfering filter is used to isolate the spectral ray from Nitrogen.
The filtered luminous intensity is then converted into an electrical current using a photoelectrical cell and amplified by an electrometer.
The tension created is proportional to the level of concentration of Nitrogen in (Argon or Helium). | <urn:uuid:d08ece77-1b18-4366-82d8-96d3f6bd9107> | 2.546875 | 131 | Product Page | Science & Tech. | 18.844333 | 95,513,852 |
Constructed wetlands have been shown to be capable of removing a wide variety of contaminants, including bacterial pollution. Wetlands are known to act as biofilters through a combination of physical, chemical and biological factors which all participate in the reduction of the number of bacteria. Five constructed wetlands in the Czech Republic were studied during 1994 and 1995 in order to determine removal of total and faecal coliform bacteria and Enterobacteriaceae. In addition, total count of aerobic and anaerobic bacteria were determined in water. Populations of nitrogen cycle bacteria were monitored on roots and rhizomes ofGlyceria maxima in the system at Doksy. The results revealed that the retention of coliform bacteria is very high and exceeds common retention values for conventional systems. The measurements also indicated that nitrifying bacteria were not present in wastewater, however, quite large numbers were found on the surface of roots and rhizomes of Glyceria. This fact can explain the significant nitrification observed in this system.
Research Article|March 01 1997
Microbial characteristics of constructed wetlands
Water Sci Technol (1997) 35 (5): 117-123.
Vlasta Ottová, Jarmila Balcarová, Jan Vymazal; Microbial characteristics of constructed wetlands. Water Sci Technol 1 March 1997; 35 (5): 117–123. doi: https://doi.org/10.2166/wst.1997.0177
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Scientists have revealed details of the world's most extreme deep-sea volcanic vents, 5 kilometres down in a rift in the Caribbean seafloor.
The undersea hot springs, which lie 0.8 kilometres deeper than any seen before, may be hotter than 450 °C and are shooting a jet of mineral-laden water more than a kilometre into the ocean above.
Despite these extreme conditions, the vents are teeming with thousands of a new species of shrimp that has a light-sensing organ on its back. And having found yet more 'black smoker' vents on an undersea mountain nearby, the researchers suggest that deep-sea vents may be more widespread around the world than anyone thought.
Reporting in the scientific journal Nature Communications this week, a team led by marine geochemist Dr Doug Connelly at the National Oceanography Centre in Southampton and marine biologist Dr Jon Copley of the University of Southampton has revealed details of the world's deepest known 'black smoker' vents, so-called for the smoky-looking hot fluids that gush from them.
During an expedition in April 2010 aboard the Royal Research Ship James Cook, the scientists used the National Oceanography Centre's robot submarine called Autosub6000 and a deep-diving vehicle, HyBIS, manufactured by the British firm, Hydro-Lek to locate and study the vents at a depth of five kilometres in the Cayman Trough, an undersea trench south of the Cayman Islands.
The vents, which the team named the Beebe Vent Field after the first scientist to venture into the deep ocean, are gushing hot fluids that are unusually rich in copper, and shooting a jet of mineral-laden water four times higher into the ocean above than other deep-sea vents. Although the scientists were not able to measure the temperature of the vents directly, these two features indicate that the world's deepest known vents may be hotter than 450 ºC, according to the researchers. "These vents may be one of the few places on the planet where we can study reactions between rocks and 'supercritical' fluids at extreme temperatures and pressures," says Connelly.
The team found a new species of pale shrimp congregating in hordes (up to 2,000 shrimp per m2) around the six-metre tall mineral spires of the vents. Lacking normal eyes, the shrimp instead have a light-sensing organ on their backs, which may help them to navigate in the faint glow of deep-sea vents. The researchers have named the shrimp Rimicaris hybisae, after the deep-sea vehicle that they used to collect them.
The Cayman shrimp is related to a species called Rimicaris exoculata, found at other deep-sea vents 4,000 kilometres away on the Mid-Atlantic Ridge. Elsewhere at the Beebe Vent Field, the team saw hundreds of white-tentacled anemones lining cracks where warm water seeps from the sea bed. "Studying the creatures at these vents, and comparing them with species at other vents around the world; will help us to understand how animals disperse and evolve in the deep ocean," says Copley.
The researchers also found black smoker vents on the upper slopes of an undersea mountain called Mount Dent. Mount Dent rises nearly three kilometres above the seafloor of the Cayman Trough, but its peak is still more than three kilometres beneath the waves. The mountain formed when a vast slab of rock was twisted up out of the ocean floor by the forces that pull the plates of the Earth's crust apart.
"Finding black smoker vents on Mount Dent was a complete surprise," says Connelly. "Hot and acidic vents have never been seen in an area like this before, and usually we don't even look for vents in places like this." Because undersea mountains like Mount Dent may be quite common in the oceans, the discovery suggests that deep-sea vents might be more widespread around the world than previously thought.
The vents on Mount Dent, which the team has named the Von Damm Vent Field to commemorate the life of geochemist Karen Von Damm, are also thronged with the new species of shrimp, along with snake-like fish, and previously unseen species of snail and a flea-like crustacean called an amphipod. "One of the big mysteries of deep-sea vents is how animals are able to disperse from vent field to vent field, crossing the apparently large distances between them," says Copley. "But maybe there are more 'stepping stones' like these out there than we realised."
The UK expedition that revealed the vents followed a US expedition in November 2009, which detected the plumes of water from deep-sea vents in the Cayman Trough. A second US expedition is currently using a deep-diving remotely operated vehicle to investigate the vents further and the UK team also plans to return to the Cayman Trough in 2013 with Isis, the National Oceanography Centre's deep-diving remotely operated vehicle, which can work at depths of up to six kilometres.
Dr Jon Copley | EurekAlert!
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A new NASA study has concluded California accumulated a debt of about 20 inches of precipitation between 2012 and 2015 -- the average amount expected to fall in the state in a single year. The deficit was driven primarily by a lack of air currents moving inland from the Pacific Ocean that are rich in water vapor.
In an average year, 20 to 50 percent of California's precipitation comes from relatively few, but extreme events called atmospheric rivers that move from over the Pacific Ocean to the California coast.
"When they say that an atmospheric river makes landfall, it's almost like a hurricane, without the winds. They cause extreme precipitation," said study lead author Andrey Savtchenko at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Savtchenko and his colleagues examined data from 17 years of satellite observations and 36 years of combined observations and model data to understand how precipitation has varied in California since 1979. The results were published Thursday in Journal of Geophysical Research - Atmospheres, a journal of the American Geophysical Union.
The state as a whole can expect an average of about 20 inches of precipitation each year, with regional differences. But, the total amount can vary as much as 30 percent from year to year, according to the study.
In non-drought periods, wet years often alternate with dry years to balance out in the short term. However, from 2012 to 2014, California accumulated a deficit of almost 13 inches, and the 2014-2015 wet season increased the debt another seven inches, for a total 20 inches accumulated deficit during the course of three dry years.
The majority of that precipitation loss is attributed to a high-pressure system in the atmosphere over the eastern Pacific Ocean that has interfered with the formation of atmospheric rivers since 2011.
Atmospheric rivers occur all over the world. They are narrow, concentrated tendrils of water vapor that travel through the atmosphere similar to, and sometimes with, the winds of a jet stream. Like a jet stream, they typically travel from west to east. The ones destined for California originate over the tropical Pacific, where warm ocean water evaporates a lot of moisture into the air. The moisture-rich atmospheric rivers, informally known as the Pineapple Express, then break northward toward North America.
Earlier this year, a NASA research aircraft participated in the CalWater 2015 field campaign to improve understanding of when and how atmospheric rivers reach California.
Some of the water vapor rains out over the ocean, but the show really begins when an atmospheric river reaches land. Two reached California around Dec. 1 and 10, 2014, and brought more than three inches of rain, according to NASA's Tropical Rainfall Measuring Mission (TRMM)'s multi-satellite dataset. The inland terrain, particularly mountains, force the moist air to higher altitudes where lower pressure causes it to expand and cool. The cooler air condenses the concentrated pool of water vapor into torrential rains, or snowfall as happens over the Sierra Nevada Mountains, where water is stored in the snowpack until the spring melt just before the growing season.
The current drought isn't the first for California. Savtchenko and his colleagues recreated a climate record for 1979 to the present using the Modern-Era Retrospective Analysis for Research and Applications, or MERRA. Their efforts show that a 27.5 inch deficit of rain and snow occurred in the state between 1986 and 1994.
"Drought has happened here before. It will happen again, and some research groups have presented evidence it will happen more frequently as the planet warms," Savtchenko said. "But, even if the climate doesn't change, are our demands for fresh water sustainable?"
The current drought has been notably severe because, since the late 1980s, California's population, industry and agriculture have experienced tremendous growth, with a correlating growth in their demand for water. Human consumption has depleted California's reservoirs and groundwater reserves, as shown by data from NASA's Gravity Recovery and Climate Experiment (GRACE) mission, leading to mandatory water rationing.
"The history of the American West is written in great decade-long droughts followed by multi-year wet periods," said climatologist Bill Patzert at NASA's Jet Propulsion Laboratory in Pasadena, California. He was not involved in the research. "Savtchenko and his team have shown how variable California rainfall is."
According to Patzert, this study added nuance to how scientists may interpret the atmospheric conditions that cause atmospheric rivers and an El Niño's capacity to bust the drought. Since March, rising sea surface temperatures in the central equatorial Pacific have indicated the formation of El Niño conditions. El Niño conditions are often associated with higher rainfall to the western United States, but it's not guaranteed.
Savtchenko and his colleagues show that El Niño contributes only six percent to California's precipitation variability and is one factor among other, more random effects that influence how much rainfall the state receives. While it's more likely El Niño increases precipitation in California, it's still possible it will have no, or even a drying, effect.
A strong El Niño that lasts through the rainy months, from November to March, is more likely to increase the amount of rain that reaches California, and Savtchenko noted the current El Niño is quickly strengthening.
The National Oceanic and Atmospheric Administration (NOAA), which monitors El Niño events, ranks it as the third strongest in the past 65 years for May and June. Still, it will likely take several years of higher than normal rain and snowfall to recover from the current drought.
"If this El Niño holds through winter, California's chances to recoup some of the precipitation increase. Unfortunately, so do the chances of floods and landslides," Savtchenko said. "Most likely the effects would be felt in late 2015-2016."
For more information about NASA's Precipitation Measurement missions, visit: http://pmm.
Ellen Gray | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
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Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
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- Research news
- Open Access
Transcription factors link rhizobia, legumes
© BioMed Central Ltd 2005
Published: 21 June 2005
Scientists have identified two putative plant transcription factors that are essential links in the symbiosis of rhizobial bacteria and legumes, according to two reports in this week's Science. The transcription factors–GRAS family proteins NSP1 and NSP2–may play distinct yet cooperative roles in regulating the development of nodules on the plant roots where the nitrogen-fixing bacteria reside.
"The interesting aspect of this is that we have a couple of GRAS proteins here that are fairly well positioned in the signaling pathway with clear phenotypic effects," Michael Udvardi, of the Max Planck Institute of Molecular Plant Physiology, Golm, Germany, and coauthor of a Perspective accompanying the studies, told The Scientist.
Legumes initiate the symbiotic relationship between bacteria and plant by emitting flavonoid compounds that are recognized by the bacteria. Rhizobia then produce Nod factors, oligosaccharides that elicit dramatic alterations in the gene expression and metabolism of both organisms. In the past few years, scientists have identified genes for "the small set of key regulators"–including a Nod factor receptor and possible plastid cation channels–in the initial steps of symbiosis, according to Ton Bisseling at Wageningen University, the Netherlands, coauthor of one of the papers. But for the first time, researchers have identified players at the first step that is specific to the rhizobia/legume interaction—what the authors of the second paper call Nod factor response factors.
Previous studies had demonstrated that nsp1 and nsp2 mutants were unable to produce the burst of gene expression that usually follows Nod factor stimulation and calcium spiking in epidermal root cells. The two teams used map-based cloning in the model legume Medicago truncatula to identify genes encoding the putative transcription factors NSP1 and NSP2.
According to the reports, the findings were consistent with earlier evidence that related proteins in the GRAS family are known to regulate transcription in other plants and contain structural elements–including leucine-rich regions and homopolymeric stretches in the N-terminal region–often found in transcriptional regulators.
Using green fluorescence protein tagging, the authors found that NSP1 and NSP2 localized to the nucleus, where they compensated for the nodulation defects in nsp1 and nsp2 mutants. That placed the proteins near the nuclear calcium/calmodulin-dependent protein kinase (CCaMK), which is known to act upstream, and to potential DNA targets. The authors conclude that this localization implies roles in calcium transduction for NSP1, which is constitutively active, and for NSP2, which shifts to the nucleus from the nuclear envelope.
It will now be important to look for "interactions between key regulators," such as the genes "directly activated by NSP1 and 2" and the potential dimer interaction of the proteins, Bisseling said in an E-mail. According to Udvardi, the next steps in this research will also involve "deciphering the subsequent changes" in the plant's gene expression, which he said "is more difficult genetically because of pleiotropic effects downstream." The next wave of genetic tools–functional genomics approaches such as DNA profiling assays–will be crucial to complement classic methods, he said.
Udvardi said the implications of the studies may go beyond legumes. Though legumes are the only plants that use rhizobia for their nitrogen fixing needs, 90% of land plants have been using part of the same signaling pathway for the past 460 million years to get help from arbuscular mycorrhizal fungi in obtaining phosphate and water from the soil, he said. And less than 20 million years ago, plant nematodes appropriated the same pathway elements to invade legumes.
According to David Bird of North Carolina State's Center for the Biology of Nematode Parasitism, who did not participate in this study, a paper he coauthored earlier this year suggests that these parasites may even have acquired genes directly from Rhizobia through horizontal transfer. The imminent completion of model legume genome sequencing projects–by this year or the next, according to Bird–mean that discoveries made here could quickly be transferable to other plant species, Udvardi said.
- Michael Udvardi, [http://www.mpimp-golm.mpg.de/leute/udvardi.html]
- M.K. Udvardi, W.R. Scheible, "GRAS genes and the symbiotic green revolution," Science, 308(5729):1749–50, June 17, 2005.Google Scholar
- A. Constans, "Giving a Nod2 the right target," The Scientist, Feb. 14, 2005., [http://www.the-scientist.com/2005/2/14/24/1]
- E. Limpens et al., "LysM domain receptor kinases regulating rhizobial Nod factor-induced infection," Science, 302(5645):630–3, 2003. Google Scholar
- H. Imaizumi-Anraku et al., "Plastid proteins crucial for symbiotic fungal and bacterial entry into plant roots," Nature, 433(7025):527–31, Feb. 3, 2005.Google Scholar
- Ton Bisseling, [http://www.mscwu.nl/tbisseling.htm]
- P. Smit et al., "NSP1 of the GRAS protein family is essential for rhizobial Nod factor-induced transcription," Science, 308(5729):1789–91, June 17, 2005.Google Scholar
- P. Kalo et al., "Nodulation signaling in legumes requires NSP2, a member of the GRAS family of transcriptional regulators," Science, 308(5729):1786–9, June 17, 2005.Google Scholar
- G.E. Oldroyd, S.R. Long, "Identification and characterization of nodulation-signaling pathway 2, a gene of Medicago truncatula involved in Nod actor signaling," Plant Physiol, 131(3):1027–32, 2003.Google Scholar
- M. Anderson, "Whisper down the vine: Plant communication," The Scientist, July 14, 2003., [http://www.the-scientist.com/2003/7/14/20/1]
- David Bird, [http://www.cals.ncsu.edu:8050/plantpath/people/faculty/bird/]
- R.R. Weerasinghe et al., "Root-knot nematodes and bacterial Nod factors elicit common signal transduction in Lotus japonicus," PNAS, 102: 3147–52, Feb. 22, 2005.Google Scholar | <urn:uuid:3de5fae5-462d-40f0-ae40-50f29a7ede3b> | 2.703125 | 1,474 | Truncated | Science & Tech. | 50.611599 | 95,513,891 |
How do I understand which is which?
C6H6 + energry -> C6H6
NaCl + energy -> Na+Cl
CH4 + 2O2 -> CO2 + 2H2O + energy
Turn on thread page Beta
Intermolecular Intra Molecular Forces watch
- Thread Starter
- 28-02-2018 15:32
- 01-03-2018 13:54
Assuming you mean:
- C6H6(l) + energy → C6H6(g), you can say that the reaction affected intermolecular forces because the single molecules don't change. The broken bonds were between molecules of benzene.
- NaCl(l) + energy → Na+(aq) + Cl-(aq) Sodium chloride is technically not a molecule, but you can see that the strong ionic bonds intra-NaCl are broken.
- This is a combustion reaction, in which the products are totally different. Both the inter- and intra- molecular bonds are affected. | <urn:uuid:e3551ed9-6cd6-425a-9a73-7c7ed1f70d83> | 2.765625 | 213 | Comment Section | Science & Tech. | 59.81542 | 95,513,908 |
Microsoft Visual Studio
Screenshot of Visual Studio 2013, editing a program's C++ source code
|Stable release||2017 version 15.7.5 (July 10, 2018[±])|
|Written in||C++ and C#|
|Available in||Chinese, Czech, English, French, German, Italian, Japanese, Korean, Polish, Portuguese (Brazil), Russian, Spanish and Turkish|
|Type||Integrated development environment|
Microsoft Visual Studio is an integrated development environment (IDE) from Microsoft. It is used to develop computer programs, as well as web sites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development platforms such as Windows API, Windows Forms, Windows Presentation Foundation, Windows Store and Microsoft Silverlight. It can produce both native code and managed code.
Visual Studio includes a code editor supporting IntelliSense (the code completion component) as well as code refactoring. The integrated debugger works both as a source-level debugger and a machine-level debugger. Other built-in tools include a code profiler, forms designer for building GUI applications, web designer, class designer, and database schema designer. It accepts plug-ins that enhance the functionality at almost every level—including adding support for source control systems (like Subversion and Git) and adding new toolsets like editors and visual designers for domain-specific languages or toolsets for other aspects of the software development lifecycle (like the Team Foundation Server client: Team Explorer).
The most basic edition of Visual Studio, the Community edition, is available free of charge.
The currently supported Visual Studio version is 2017. Microsoft announced 2019 on June 6, 2018, with its release timing to be shared "in the coming months," promising "to deliver ... quickly and iteratively."
- 1 Architecture
- 2 Features
- 3 Supported products
- 4 Editions
- 5 History
- 6 Related products
- 7 See also
- 8 References
- 9 External links
Visual Studio does not support any programming language, solution or tool intrinsically; instead, it allows the plugging of functionality coded as a VSPackage. When installed, the functionality is available as a Service. The IDE provides three services: SVsSolution, which provides the ability to enumerate projects and solutions; SVsUIShell, which provides windowing and UI functionality (including tabs, toolbars and tool windows); and SVsShell, which deals with registration of VSPackages. In addition, the IDE is also responsible for coordinating and enabling communication between services. All editors, designers, project types and other tools are implemented as VSPackages. Visual Studio uses COM to access the VSPackages. The Visual Studio SDK also includes the Managed Package Framework (MPF), which is a set of managed wrappers around the COM-interfaces that allow the Packages to be written in any CLI compliant language. However, MPF does not provide all the functionality exposed by the Visual Studio COM interfaces. The services can then be consumed for creation of other packages, which add functionality to the Visual Studio IDE.
Support for programming languages is added by using a specific VSPackage called a Language Service. A language service defines various interfaces which the VSPackage implementation can implement to add support for various functionalities. Functionalities that can be added this way include syntax coloring, statement completion, brace matching, parameter information tooltips, member lists and error markers for background compilation. If the interface is implemented, the functionality will be available for the language. Language services are implemented on a per-language basis. The implementations can reuse code from the parser or the compiler for the language. Language services can be implemented either in native code or managed code. For native code, either the native COM interfaces or the Babel Framework (part of Visual Studio SDK) can be used. For managed code, the MPF includes wrappers for writing managed language services.
Visual Studio does not include any source control support built in but it defines two alternative ways for source control systems to integrate with the IDE. A Source Control VSPackage can provide its own customised user interface. In contrast, a source control plugin using the MSSCCI (Microsoft Source Code Control Interface) provides a set of functions that are used to implement various source control functionality, with a standard Visual Studio user interface. MSSCCI was first used to integrate Visual SourceSafe with Visual Studio 6.0 but was later opened up via the Visual Studio SDK. Visual Studio .NET 2002 used MSSCCI 1.1, and Visual Studio .NET 2003 used MSSCCI 1.2. Visual Studio 2005, 2008 and 2010 use MSSCCI Version 1.3, which adds support for rename and delete propagation as well as asynchronous opening.
Visual Studio supports running multiple instances of the environment (each with its own set of VSPackages). The instances use different registry hives (see MSDN's definition of the term "registry hive" in the sense used here) to store their configuration state and are differentiated by their AppId (Application ID). The instances are launched by an AppId-specific .exe that selects the AppId, sets the root hive and launches the IDE. VSPackages registered for one AppId are integrated with other VSPackages for that AppId. The various product editions of Visual Studio are created using the different AppIds. The Visual Studio Express edition products are installed with their own AppIds, but the Standard, Professional and Team Suite products share the same AppId. Consequently, one can install the Express editions side-by-side with other editions, unlike the other editions which update the same installation. The professional edition includes a superset of the VSPackages in the standard edition and the team suite includes a superset of the VSPackages in both other editions. The AppId system is leveraged by the Visual Studio Shell in Visual Studio 2008.
The Visual Studio code editor also supports setting bookmarks in code for quick navigation. Other navigational aids include collapsing code blocks and incremental search, in addition to normal text search and regex search. The code editor also includes a multi-item clipboard and a task list. The code editor supports code snippets, which are saved templates for repetitive code and can be inserted into code and customized for the project being worked on. A management tool for code snippets is built in as well. These tools are surfaced as floating windows which can be set to automatically hide when unused or docked to the side of the screen. The Visual Studio code editor also supports code refactoring including parameter reordering, variable and method renaming, interface extraction and encapsulation of class members inside properties, among others.
Visual Studio features background compilation (also called incremental compilation). As code is being written, Visual Studio compiles it in the background in order to provide feedback about syntax and compilation errors, which are flagged with a red wavy underline. Warnings are marked with a green underline. Background compilation does not generate executable code, since it requires a different compiler than the one used to generate executable code. Background compilation was initially introduced with Microsoft Visual Basic but has now been expanded for all included languages.
Visual Studio includes a debugger that works both as a source-level debugger and as a machine-level debugger. It works with both managed code as well as native code and can be used for debugging applications written in any language supported by Visual Studio. In addition, it can also attach to running processes and monitor and debug those processes. If source code for the running process is available, it displays the code as it is being run. If source code is not available, it can show the disassembly. The Visual Studio debugger can also create memory dumps as well as load them later for debugging. Multi-threaded programs are also supported. The debugger can be configured to be launched when an application running outside the Visual Studio environment crashes.
The debugger allows setting breakpoints (which allow execution to be stopped temporarily at a certain position) and watches (which monitor the values of variables as the execution progresses). Breakpoints can be conditional, meaning they get triggered when the condition is met. Code can be stepped over, i.e., run one line (of source code) at a time. It can either step into functions to debug inside it, or step over it, i.e., the execution of the function body isn't available for manual inspection. The debugger supports Edit and Continue, i.e., it allows code to be edited as it is being debugged. When debugging, if the mouse pointer hovers over any variable, its current value is displayed in a tooltip ("data tooltips"), where it can also be modified if desired. During coding, the Visual Studio debugger lets certain functions be invoked manually from the
Immediate tool window. The parameters to the method are supplied at the Immediate window.
Visual Studio includes a host of visual designers to aid in the development of applications. These tools include:
- Windows Forms Designer
- The Windows Forms designer is used to build GUI applications using Windows Forms. Layout can be controlled by housing the controls inside other containers or locking them to the side of the form. Controls that display data (like textbox, list box and grid view) can be bound to data sources like databases or queries. Data-bound controls can be created by dragging items from the Data Sources window onto a design surface. The UI is linked with code using an event-driven programming model. The designer generates either C# or VB.NET code for the application.
- WPF Designer
- The WPF designer, codenamed Cider, was introduced with Visual Studio 2008. Like the Windows Forms designer it supports the drag and drop metaphor. It is used to author user interfaces targeting Windows Presentation Foundation. It supports all WPF functionality including data binding and automatic layout management. It generates XAML code for the UI. The generated XAML file is compatible with Microsoft Expression Design, the designer-oriented product. The XAML code is linked with code using a code-behind model.
- Web designer/development
- Class designer
- The Class Designer is used to author and edit the classes (including its members and their access) using UML modeling. The Class Designer can generate C# and VB.NET code outlines for the classes and methods. It can also generate class diagrams from hand-written classes.
- Data designer
- The data designer can be used to graphically edit database schemas, including typed tables, primary and foreign keys and constraints. It can also be used to design queries from the graphical view.
- Mapping designer
- From Visual Studio 2008 onwards, the mapping designer is used by LINQ to SQL to design the mapping between database schemas and the classes that encapsulate the data. The new solution from ORM approach, ADO.NET Entity Framework, replaces and improves the old technology.
- Open Tabs Browser
- The open tabs browser is used to list all open tabs and to switch between them. It is invoked using
- Properties Editor
- The Properties Editor tool is used to edit properties in a GUI pane inside Visual Studio. It lists all available properties (both read-only and those which can be set) for all objects including classes, forms, web pages and other items.
- Object Browser
- The Object Browser is a namespace and class library browser for Microsoft .NET. It can be used to browse the namespaces (which are arranged hierarchically) in managed assemblies. The hierarchy may or may not reflect the organization in the file system.
- Solution Explorer
- In Visual Studio parlance, a solution is a set of code files and other resources that are used to build an application. The files in a solution are arranged hierarchically, which might or might not reflect the organization in the file system. The Solution Explorer is used to manage and browse the files in a solution.
- Team Explorer
- Team Explorer is used to integrate the capabilities of Team Foundation Server, the Revision Control System into the IDE (and the basis for Microsoft's CodePlex hosting environment for open source projects). In addition to source control it provides the ability to view and manage individual work items (including bugs, tasks and other documents) and to browse TFS statistics. It is included as part of a TFS install and is also available as a download for Visual Studio separately. Team Explorer is also available as a stand-alone environment solely to access TFS services.
- Data Explorer
- Data Explorer is used to manage databases on Microsoft SQL Server instances. It allows creation and alteration of database tables (either by issuing T-SQL commands or by using the Data designer). It can also be used to create queries and stored procedures, with the latter in either T-SQL or in managed code via SQL CLR. Debugging and IntelliSense support is available as well.
- Server Explorer
- The Server Explorer tool is used to manage database connections on an accessible computer. It is also used to browse running Windows Services, performance counters, Windows Event Log and message queues and use them as a datasource.
- PreEmptive Protection-Dotfuscator Community Edition
- Visual Studio includes a free 'light' version of Dotfuscator by PreEmptive Solutions which obfuscates and hardens applications to help secure trade secrets (IP), reduce piracy/counterfeiting, protect against tampering and unauthorized debugging. Dotfuscator works with all flavors of .NET including ASP.NET, Xamarin, Unity and UWP.
- Text Generation Framework
- Visual Studio includes a full text generation framework called T4 which enables Visual Studio to generate text files from templates either in the IDE or via code.
- ASP.NET Web Site Administration Tool
- The ASP.NET Web Site Administration Tool allows for the configuration of ASP.NET websites.
- Visual Studio Tools for Office
- Visual Studio Tools for Office is a SDK and an add-in for Visual Studio that includes tools for developing for the Microsoft Office suite. Previously (for Visual Studio .NET 2003 and Visual Studio 2005) it was a separate SKU that supported only Visual C# and Visual Basic languages or was included in the Team Suite. With Visual Studio 2008, it is no longer a separate SKU but is included with Professional and higher editions. A separate runtime is required when deploying VSTO solutions.
Visual Studio allows developers to write extensions for Visual Studio to extend its capabilities. These extensions "plug into" Visual Studio and extend its functionality. Extensions come in the form of macros, add-ins, and packages. Macros represent repeatable tasks and actions that developers can record programmatically for saving, replaying, and distributing. Macros, however, cannot implement new commands or create tool windows. They are written using Visual Basic and are not compiled. Add-Ins provide access to the Visual Studio object model and can interact with the IDE tools. Add-Ins can be used to implement new functionality and can add new tool windows. Add-Ins are plugged into the IDE via COM and can be created in any COM-compliant languages. Packages are created using the Visual Studio SDK and provide the highest level of extensibility. They can create designers and other tools, as well as integrate other programming languages. The Visual Studio SDK provides unmanaged APIs as well as a managed API to accomplish these tasks. However, the managed API isn't as comprehensive as the unmanaged one. Extensions are supported in the Standard (and higher) versions of Visual Studio 2005. Express Editions do not support hosting extensions.
Visual Studio 2008 introduced the Visual Studio Shell that allows for development of a customized version of the IDE. The Visual Studio Shell defines a set of VSPackages that provide the functionality required in any IDE. On top of that, other packages can be added to customize the installation. The Isolated mode of the shell creates a new AppId where the packages are installed. These are to be started with a different executable. It is aimed for development of custom development environments, either for a specific language or a specific scenario. The Integrated mode installs the packages into the AppId of the Professional/Standard/Team System editions, so that the tools integrate into these editions. The Visual Studio Shell is available as a free download.
After the release of Visual Studio 2008, Microsoft created the Visual Studio Gallery. It serves as the central location for posting information about extensions to Visual Studio. Community developers as well as commercial developers can upload information about their extensions to Visual Studio .NET 2002 through Visual Studio 2010. Users of the site can rate and review the extensions to help assess the quality of extensions being posted. An extension is stored in a VSIX file. Internally a VSIX file is a ZIP file that contains some XML files, and possibly one or more DLL's. One of the main advantages of these extensions is that they do not require Administrator rights to be installed. RSS feeds to notify users on updates to the site and tagging features are also planned.
- Microsoft Visual C++
- Microsoft Visual C++ is Microsoft's implementation of the C and C++ compiler and associated languages-services and specific tools for integration with the Visual Studio IDE. It can compile either in C mode or C++ mode. For C, it follows the 1990 version of the ISO C standard with parts of C99 specification along with MS-specific additions in the form of libraries. For C++, it follows the ANSI C++ specification along with a few C++11 features. It also supports the C++/CLI specification to write managed code, as well as mixed-mode code (a mix of native and managed code). Microsoft positions Visual C++ for development in native code or in code that contains both native as well as managed components. Visual C++ supports COM as well as the MFC library. For MFC development, it provides a set of wizards for creating and customizing MFC boilerplate code, and creating GUI applications using MFC. Visual C++ can also use the Visual Studio forms designer to design UI graphically. Visual C++ can also be used with the Windows API. It also supports the use of intrinsic functions, which are functions recognized by the compiler itself and not implemented as a library. Intrinsic functions are used to expose the SSE instruction set of modern CPUs. Visual C++ also includes the OpenMP (version 2.0) specification.
- Microsoft Visual C#
- Microsoft Visual C#, Microsoft's implementation of the C# language, targets the .NET Framework, along with the language services that lets the Visual Studio IDE support C# projects. While the language services are a part of Visual Studio, the compiler is available separately as a part of the .NET Framework. The Visual C# 2008, 2010 and 2012 compilers support versions 3.0, 4.0 and 5.0 of the C# language specifications, respectively. Visual C# supports the Visual Studio Class designer, Forms designer, and Data designer among others.
- Microsoft Visual Basic
- Microsoft Visual Basic is Microsoft's implementation of the VB.NET language and associated tools and language services. It was introduced with Visual Studio .NET (2002). Microsoft has positioned Visual Basic for Rapid Application Development. Visual Basic can be used to author both console applications as well as GUI applications. Like Visual C#, Visual Basic also supports the Visual Studio Class designer, Forms designer, and Data designer among others. Like C#, the VB.NET compiler is also available as a part of .NET Framework, but the language services that let VB.NET projects be developed with Visual Studio, are available as a part of the latter.
- Microsoft Visual Web Developer
- Microsoft Visual Web Developer is used to create web sites, web applications and web services using ASP.NET. Either C# or VB.NET languages can be used. Visual Web Developer can use the Visual Studio Web Designer to graphically design web page layouts.
- Team Foundation Server
- Team Foundation Server is intended for collaborative software development projects and acts as the server-side backend providing source control, data collection, reporting, and project-tracking functionality. It also includes the Team Explorer, the client tool for TFS services, which is integrated inside Visual Studio Team System.
- Visual FoxPro
- Visual FoxPro is a data-centric object-oriented and procedural programming language produced by Microsoft. It derives from FoxPro (originally known as FoxBASE) which was developed by Fox Software beginning in 1984. Visual FoxPro is tightly integrated with its own relational database engine, which extends FoxPro's xBase capabilities to support SQL queries and data manipulation. Visual FoxPro is a full-featured, dynamic programming language that does not require the use of an additional general-purpose programming environment. In 2007, Visual FoxPro was discontinued after version 9 Service Pack 2. It was supported until 2015.
- Visual SourceSafe
- Microsoft Visual SourceSafe is a source control software package oriented towards small software-development projects. The SourceSafe database is a multi-user, multi-process file-system database, using the Windows file system database primitives to provide locking and sharing support. All versions are multi-user, using SMB (file server) networking. However, with Visual SourceSafe 2005, other client–server modes were added, Lan Booster and VSS Internet (which used HTTP/HTTPS). Visual SourceSafe 6.0 was available as a stand-alone product and was included with Visual Studio 6.0, and other products such as Office Developer Edition. Visual SourceSafe 2005 was available as a stand-alone product and included with the 2005 Team Suite. Team Foundation Server has superseded VSS as Microsoft's recommended platform for source control.
- Microsoft Visual J++/Microsoft Visual J#
- Microsoft Visual J++ was Microsoft's implementation of the Java language (with Microsoft-specific extensions) and associated language services. It was discontinued as a result of litigation from Sun Microsystems, and the technology was recycled into Visual J#, Microsoft's Java compiler for .NET Framework. J# was available with Visual Studio 2005 (supported until 2015) but was discontinued in Visual Studio 2008.
- Visual InterDev
- Visual InterDev was used to create web applications using Microsoft Active Server Pages (ASP) technologies. It supports code completion and includes database server management tools. It has been replaced with Microsoft Visual Web Developer.
The Community edition was announced on 12 November 2014, as a new free version similar in functionality to Visual Studio Professional. Prior to this date, the only free editions of Visual Studio were the feature-limited Express variants. Unlike the Express variants, Visual Studio Community supports multiple languages, and provides support for extensions. However, the license restricts use to individual developers or to teams developing open source projects. Visual Studio Community is oriented towards individual developers and small teams.
As of Visual Studio 2010, the Professional edition is the entry level commercial edition of Visual Studio. (Previously, a more feature restricted Standard edition was available.) It provides an IDE for all supported development languages. MSDN support is available as MSDN Essentials or the full MSDN library depending on licensing. It supports XML and XSLT editing, and can create deployment packages that only use ClickOnce and MSI. It includes tools like Server Explorer and integration with Microsoft SQL Server also. Windows Mobile development support was included in Visual Studio 2005 Standard, however, with Visual Studio 2008, it is only available in Professional and higher editions. Windows Phone 7 development support was added to all editions in Visual Studio 2010. Development for Windows Mobile is no longer supported in Visual Studio 2010; it is superseded by Windows Phone 7.
In addition to the features provided by the Professional edition, the Enterprise edition provides a new set of software development, database development, collaboration, metrics, architecture, testing and reporting tools.
The Test Professional edition was introduced with Visual Studio 2010. Its focus is the dedicated tester role. It includes support for the management of test environments, the ability to start and report on tests and to connect to Team Foundation Server. It does not include support for development or authoring of tests.
Visual Studio Express is a stripped-down version of Visual Studio for students and hobbyists, first introduced with Visual Studio 2005 and discontinued with Visual Studio 2015. Originally, it consisted of several editions, each of which targeted a single programming language. Visual Studio Express 2005, 2008 and 2010 consisted of the following editions that could have been installed side-by-side:
- Visual Basic Express
- Visual C++ Express
- Visual C# Express
- Visual J# Express (2005 only)
- Visual Web Developer Express
- Visual Studio Express for Windows Phone (2010 only)
Visual Studio 2012, 2013 and 2015 consist of editions geared towards different platforms instead:
- Express for Web: focuses on developing web apps
- Express for Windows: focuses on developing Universal Windows Platform apps
- Express for Desktop: focuses on developing traditional apps for Windows, using Windows API
- Team Foundation Server Express: provides source control and application lifecycle management
- Express for Windows Phone (2012 only): focuses on software development for Windows Phone 7.5 and 8.0
Versions prior to 2013 Update 2 do not include support for plug-ins. x64 compilers are not included in the Visual Studio Express edition IDEs, but are available as part of a Windows Software Development Kit that can be installed separately. After an initial announcement that the Express 2012 release would be restricted to creating Windows 8 Metro-style apps, Microsoft responded to negative developer feedback by reversing that decision and announcing that desktop application development would also be supported.
The first version of Visual Studio was Visual Studio 97. Before that, Visual Basic, Visual C++, Visual FoxPro and Visual SourceSafe were sold as separate products.
|Visual Studio 2019||Unknown||16.0||To be announced||To be announced||To be announced|
|Visual Studio 2017||Dev15
|15.0||3.5 – 4.7||1.0-1.1, 2.0||March 7, 2017|
|Visual Studio 2015||Dev14
|14.0||2.0 – 4.6||1.0||July 20, 2015|
|Visual Studio 2013||Dev12
|12.0||2.0 – 4.5.2||N/A||October 17, 2013|
|Visual Studio 2012||Dev11
|11.0||2.0 – 4.5.2||N/A||September 12, 2012|
|Visual Studio 2010||Dev10, Rosario||10.0||2.0 – 4.0||N/A||April 12, 2010|
|Visual Studio 2008||Orcas||9.0||2.0, 3.0, 3.5||N/A||November 19, 2007|
|Visual Studio 2005||Whidbey||8.0||2.0, 3.0||N/A||November 7, 2005|
|Visual Studio .NET 2003||Everett||7.1||1.1||N/A||April 24, 2003|
|Visual Studio .NET (2002)||Rainier||7.0||1.0||N/A||February 13, 2002|
|Visual Studio 6.0||Aspen||6.0||N/A||N/A||June 1998|
|Visual Studio 97||Boston||5.0||N/A||N/A||February 1997|
Microsoft first released Visual Studio (codenamed Boston, for the city of the same name, thus beginning the VS codenames related to places) in 1997, bundling many of its programming tools together for the first time. Visual Studio 97 came in two editions: Visual Studio Professional and Visual Studio Enterprise, the professional edition has three CDs, and the enterprise on four CDs. It included Visual J++ 1.1 for Java programming and introduced Visual InterDev for creating dynamically generated web sites using Active Server Pages. There was a single companion CD that contained the Microsoft Developer Network library.
Visual Studio 97 was Microsoft's first attempt at using the same development environment for multiple languages. Visual J++, InterDev, and the MSDN Library had all been using the same 'environment', called Developer Studio.
Visual Studio was also sold as a bundle with the separate IDEs used for Visual C++, Visual Basic and Visual FoxPro.
The next version, version 6.0 (codenamed Aspen, after the ski resort in Colorado), was released in June 1998 and is the last version to run on the Windows 9x platform. Each version of each language in part also settled to v6.0, including Visual J++ which was prior v1.1, and Visual InterDev at the 1st release. The v6 edition of Microsoft was the core environment for the next four releases to provide programmers with an integrated look-alike platform. This led Microsoft to transition the development on the platform independent .NET Framework.
Visual Studio 6.0 was the last version to include Visual J++, which Microsoft removed as part of a settlement with Sun Microsystems that required Microsoft Internet Explorer not to provide support for the Java virtual machine.
Visual Studio 6.0 came in two editions: Professional and Enterprise. The Enterprise edition contained extra features not found in Professional edition, including:
- Application Performance Explorer
- Automation Manager
- Microsoft Visual Modeler
- RemAuto Connection Manager
- Visual Studio Analyzer
Visual Studio was also sold as a bundle with the separate IDEs used for Visual C++, Visual Basic and Visual FoxPro.
Microsoft released Visual Studio .NET (VS.NET), codenamed Rainier (for Washington's Mount Rainier), in February 2002 (the beta version was released via Microsoft Developer Network in 2001). The biggest change was the introduction of a managed code development environment using the .NET Framework. Programs developed using .NET are not compiled to machine language (like C++ is, for example) but instead to a format called Microsoft Intermediate Language (MSIL) or Common Intermediate Language (CIL). When a CIL application executes, it is compiled while being executed into the appropriate machine language for the platform it is being executed on, thereby making code portable across several platforms. Programs compiled into CIL can be executed only on platforms which have an implementation of Common Language Infrastructure. It is possible to run CIL programs in Linux or Mac OS X using non-Microsoft .NET implementations like Mono and DotGNU.
Visual Studio .NET 2002 shipped in four editions: Academic, Professional, Enterprise Developer, and Enterprise Architect. Microsoft introduced C# (C-sharp), a new programming language, that targets .NET. It also introduced the successor to Visual J++ called Visual J#. Visual J# programs use Java's language-syntax. However, unlike Visual J++ programs, Visual J# programs can only target the .NET Framework, not the Java Virtual Machine that all other Java tools target.
Visual Basic changed drastically to fit the new framework, and the new version was called Visual Basic .NET. Microsoft also added extensions to C++, called Managed Extensions for C++, so .NET programs could be created in C++.
Visual Studio .NET can produce applications targeting Windows (using the Windows Forms part of the .NET Framework), the Web (using ASP.NET and Web Services) and, with an add-in, portable devices (using the .NET Compact Framework).
The Visual Studio .NET environment was rewritten to partially use .NET. All languages are versions of Visual Studio, it has a cleaner interface and greater cohesiveness. It is also more customizable with tool windows that automatically hide when not in use. While Visual FoxPro 7 started out as part of Visual Studio .NET 2002, and early VS betas allowed debugging inside VFP-based DLLs, it was removed before release to follow its own development track.
The internal version number of Visual Studio .NET 2002 is version 7.0. Microsoft released Service Pack 1 for Visual Studio .NET 2002 in March 2005.
In April 2003, Microsoft introduced a minor upgrade to Visual Studio .NET called Visual Studio .NET 2003, codenamed Everett (for the city of the same name). It includes an upgrade to the .NET Framework, version 1.1, and is the first release to support developing programs for mobile devices, using ASP.NET or the .NET Compact Framework. The Visual C++ compiler's standards-compliance improved, especially in the area of partial template specialization. Visual C++ Toolkit 2003 is a version of the same C++ compiler shipped with Visual Studio .NET 2003 without the IDE that Microsoft made freely available. As of 2010[update] it is no longer available and the Express Editions have superseded it. The internal version number of Visual Studio .NET 2003 is version 7.1 while the file format version is 8.0.
Visual Studio .NET 2003 shipped in four editions: Academic, Professional, Enterprise Developer, and Enterprise Architect. The Visual Studio .NET 2003 Enterprise Architect edition includes an implementation of Microsoft Visio 2002's modeling technologies, including tools for creating Unified Modeling Language-based visual representations of an application's architecture, and an object-role modeling (ORM) and logical database-modeling solution. "Enterprise Templates" were also introduced, to help larger development teams standardize coding styles and enforce policies around component usage and property settings.
Service Pack 1 was released 13 September 2006.
Visual Studio 2005, codenamed Whidbey (a reference to Whidbey Island in Puget Sound region), was released online in October 2005 and to retail stores a few weeks later. Microsoft removed the ".NET" moniker from Visual Studio 2005 (as well as every other product with .NET in its name), but it still primarily targets the .NET Framework, which was upgraded to version 2.0. It is the last version available for Windows 2000 and also the last version to be able to target Windows 98, Windows Me and Windows NT 4.0 for C++ applications.
Visual Studio 2005's internal version number is 8.0 while the file format version is 9.0. Microsoft released Service Pack 1 for Visual Studio 2005 on 14 December 2006. An additional update for Service Pack 1 that offers Windows Vista compatibility was made available on 3 June 2007.
Visual Studio 2005 was upgraded to support all the new features introduced in .NET Framework 2.0, including generics and ASP.NET 2.0. The IntelliSense feature in Visual Studio was upgraded for generics and new project types were added to support ASP.NET web services. Visual Studio 2005 additionally introduces support for a new task-based build platform called Microsoft Build Engine (MSBuild) which employs a new XML-based project file format. Visual Studio 2005 also includes a local web server, separate from IIS, that can host ASP.NET applications during development and testing. It also supports all SQL Server 2005 databases. Database designers were upgraded to support the ADO.NET 2.0, which is included with .NET Framework 2.0. C++ also got a similar upgrade with the addition of C++/CLI which is slated to replace the use of Managed C++. Other new features of Visual Studio 2005 include the "Deployment Designer" which allows application designs to be validated before deployments, an improved environment for web publishing when combined with ASP.NET 2.0 and load testing to see application performance under various sorts of user loads. Starting with the 2005 edition, Visual Studio also added extensive 64-bit support. While the host development environment itself is only available as a 32-bit application, Visual C++ 2005 supports compiling for x86-64 (AMD64 and Intel 64) as well as IA-64 (Itanium). The Platform SDK included 64-bit compilers and 64-bit versions of the libraries.
Microsoft also announced Visual Studio Tools for Applications as the successor to Visual Basic for Applications (VBA) and VSA (Visual Studio for Applications). VSTA 1.0 was released to manufacturing along with Office 2007. It is included with Office 2007 and is also part of the Visual Studio 2005 SDK. VSTA consists of a customized IDE, based on the Visual Studio 2005 IDE, and a runtime that can be embedded in applications to expose its features via the .NET object model. Office 2007 applications continue to integrate with VBA, except for InfoPath 2007 which integrates with VSTA. Version 2.0 of VSTA (based on Visual Studio 2008) was released in April 2008. It is significantly different from the first version, including features such as dynamic programming and support for WPF, WCF, WF, LINQ, and .NET 3.5 Framework.
Visual Studio 2008, and Visual Studio Team System 2008 codenamed Orcas (a reference to Orcas Island, also an island in Puget Sound region, like Whidbey for the previous 2005 release), were released to MSDN subscribers on 19 November 2007 alongside .NET Framework 3.5. The source code for the Visual Studio 2008 IDE is available under a shared source license to some of Microsoft's partners and ISVs. Microsoft released Service Pack 1 for Visual Studio 2008 on 11 August 2008. The internal version number of Visual Studio 2008 is version 9.0 while the file format version is 10.0. Visual Studio 2008 is the last version to support targeting Windows 2000 for C++ applications.
Visual Studio 2008 is focused on development of Windows Vista, 2007 Office system, and Web applications. For visual design, a new Windows Presentation Foundation visual designer and a new HTML/CSS editor influenced by Microsoft Expression Web are included. J# is not included. Visual Studio 2008 requires .NET 3.5 Framework and by default configures compiled assemblies to run on .NET Framework 3.5, but it also supports multi-targeting which lets the developers choose which version of the .NET Framework (out of 2.0, 3.0, 3.5, Silverlight CoreCLR or .NET Compact Framework) the assembly runs on. Visual Studio 2008 also includes new code analysis tools, including the new Code Metrics tool (only in Team Edition and Team Suite Edition). For Visual C++, Visual Studio adds a new version of Microsoft Foundation Classes (MFC 9.0) that adds support for the visual styles and UI controls introduced with Windows Vista. For native and managed code interoperability, Visual C++ introduces the STL/CLR, which is a port of the C++ Standard Template Library (STL) containers and algorithms to managed code. STL/CLR defines STL-like containers, iterators and algorithms that work on C++/CLI managed objects.
Visual Studio Debugger includes features targeting easier debugging of multi-threaded applications. In debugging mode, in the Threads window, which lists all the threads, hovering over a thread displays the stack trace of that thread in tooltips. The threads can directly be named and flagged for easier identification from that window itself. In addition, in the code window, along with indicating the location of the currently executing instruction in the current thread, the currently executing instructions in other threads are also pointed out. The Visual Studio debugger supports integrated debugging of the .NET 3.5 Framework Base Class Library (BCL) which can dynamically download the BCL source code and debug symbols and allow stepping into the BCL source during debugging. As of 2010[update] a limited subset of the BCL source is available, with more library support planned for later.
The Visual Studio 2010 IDE was redesigned which, according to Microsoft, clears the UI organization and "reduces clutter and complexity." The new IDE better supports multiple document windows and floating tool windows, while offering better multi-monitor support. The IDE shell has been rewritten using the Windows Presentation Foundation (WPF), whereas the internals have been redesigned using Managed Extensibility Framework (MEF) that offers more extensibility points than previous versions of the IDE that enabled add-ins to modify the behavior of the IDE.
Visual Studio 2010 comes with .NET Framework 4 and supports developing applications targeting Windows 7. It supports IBM DB2 and Oracle databases, in addition to Microsoft SQL Server. It has integrated support for developing Microsoft Silverlight applications, including an interactive designer. Visual Studio 2010 offers several tools to make parallel programming simpler: in addition to the Parallel Extensions for the .NET Framework and the Parallel Patterns Library for native code, Visual Studio 2010 includes tools for debugging parallel applications. The new tools allow the visualization of parallel Tasks and their runtime stacks. Tools for profiling parallel applications can be used for visualization of thread wait-times and thread migrations across processor cores. Intel and Microsoft have jointly pledged support for a new Concurrency Runtime in Visual Studio 2010 and Intel has launched parallelism support in Parallel Studio as an add-on for Visual Studio.
The Visual Studio 2010 code editor now highlights references; whenever a symbol is selected, all other usages of the symbol are highlighted. It also offers a Quick Search feature to incrementally search across all symbols in C++, C# and VB.NET projects. Quick Search supports substring matches and camelCase searches. The Call Hierarchy feature allows the developer to see all the methods that are called from a current method as well as the methods that call the current one. IntelliSense in Visual Studio supports a consume-first mode which developers can opt into. In this mode, IntelliSense does not auto-complete identifiers; this allows the developer to use undefined identifiers (like variable or method names) and define those later. Visual Studio 2010 can also help in this by automatically defining them, if it can infer their types from usage. Current versions of Visual Studio have a known bug which makes IntelliSense unusable for projects using pure C (not C++).
Visual Studio 2010 features a new Help System replacing the MSDN Library viewer. The Help System is no longer based on Microsoft Help 2 and does not use Microsoft Document Explorer. Dynamic help containing links to related help topics based on where the developer was in the IDE has been removed in the shipping product, but can be added back using a download from Microsoft.
Visual Studio Ultimate 2010 replaces Visual Studio 2008 Team Suite. It includes new modeling tools, such as the Architecture Explorer, which graphically displays projects and classes and the relationships between them. It supports UML activity diagram, component diagram, (logical) class diagram, sequence diagram, and use case diagram. Visual Studio Ultimate 2010 also includes Test Impact Analysis which provides hints on which test cases are impacted by modifications to the source code, without actually running the test cases. This speeds up testing by avoiding running unnecessary test cases.
Visual Studio Ultimate 2010 also includes a historical debugger for managed code called IntelliTrace. Unlike a traditional debugger that records only the currently active stack, IntelliTrace records all events, such as prior function calls, method parameters, events and exceptions. This allows the code execution to be rewound in case a breakpoint was not set where the error occurred. Debugging with IntelliTrace causes the application to run more slowly than debugging without it, and uses more memory as additional data needs to be recorded. Microsoft allows configuration of how much data should be recorded, in effect, allowing developers to balance the speed of execution and resource usage. The Lab Management component of Visual Studio Ultimate 2010 uses virtualization to create a similar execution environment for testers and developers. The virtual machines are tagged with checkpoints which can later be investigated for issues, as well as to reproduce the issue. Visual Studio Ultimate 2010 also includes the capability to record test runs that capture the specific state of the operating environment as well as the precise steps used to run the test. These steps can then be played back to reproduce issues.
The final build of Visual Studio 2012 was announced on 1 August 2012 and the official launch event was held on 12 September 2012.
On 16 September 2011, a complete 'Developer Preview' of Visual Studio 11 was published on Microsoft's website. Visual Studio 11 Developer Preview requires Windows 7, Windows Server 2008 R2, Windows 8, or later operating systems. Versions of Microsoft Foundation Class Library (MFC) and C runtime (CRT) included with this release cannot produce software that is compatible with Windows XP or Windows Server 2003 except by using native multi-targeting and foregoing the newest libraries, compilers, and headers. However, on 15 June 2012, a blog post on the VC++ Team blog announced that based on customer feedback, Microsoft would re-introduce native support for Windows XP targets (though not for XP as a development platform) in a version of Visual C++ to be released later in the fall of 2012. "Visual Studio 2012 Update 1" (Visual Studio 2012.1) was released in November 2012. This update added support for Windows XP targets and also added other new tools and features (e.g. improved diagnostics and testing support for Windows Store apps).
On 24 August 2011, a blog post by Sumit Kumar, a Program Manager on the Visual C++ team, listed some of the features of the upcoming version of the Visual Studio C++ IDE:
- Semantic colorization: Improved syntax coloring, various user-defined or default colors for C++ syntax such as macros, enumerations, typenames and functions.
- Reference highlighting: Selection of a symbol highlights all of the references to that symbol within scope.
- New Solution Explorer: The new Solution Explorer allows for visualization of class and file hierarchies within a solution/project. It can search for calls to functions and uses of classes.
- Automatic display of IntelliSense list: IntelliSense is automatically displayed whilst typing code, as opposed to previous versions where it had to be explicitly invoked through use of certain operators (i.e. the scope operator (::)) or shortcut keys (Ctrl-Space or Ctrl-J).
- Member list filtering: IntelliSense uses fuzzy logic to determine which functions/variables/types to display in the list.
- Code snippets: Code snippets are included in IntelliSense to automatically generate relevant code based on the user's parameters, custom code snippets can be created.
The source code of Visual Studio 2012 consists of approximately 50 million lines of code.
During Visual Studio 11 beta, Microsoft eliminated the use of color within tools except in cases where color is used for notification or status change purposes. However, the use of color was returned after feedback demanding more contrast, differentiation, clarity and "energy" in the user interface.
In Visual Studio 2012 RC, a major change to the interface is the use of all-caps menu bar, as part of the campaign to keep Visual Studio consistent with the direction of other Microsoft user interfaces, and to provide added structure to the top menu bar area. The redesign was criticized for being hard to read, and going against the trends started by developers to use CamelCase to make words stand out better. Some speculated that the root cause of the redesign was to incorporate the simplistic look and feel of Metro programs. However, there exists a Windows Registry option to allow users to disable the all-caps interface.
The preview for Visual Studio 2013 was announced at the Build 2013 conference and made available on 26 June 2013. The Visual Studio 2013 RC (Release Candidate) was made available to developers on MSDN on 9 September 2013.
The final release of Visual Studio 2013 became available for download on 17 October 2013 along with .NET 4.5.1. Visual Studio 2013 officially launched on 13 November 2013 at a virtual launch event keynoted by S. Somasegar and hosted on events
Initially referred to as Visual Studio "14", the first Community Technology Preview (CTP) was released on 3 June 2014 and the Release Candidate was released on 29 April 2015; Visual Studio 2015 was officially announced as the final name on 12 November 2014.
Visual Studio 2015 RTM was released on 20 July 2015. Visual Studio 2015 Update 1 was released on 30 November 2015. Visual Studio 2015 Update 2 was released on 30 March 2016. Visual Studio 2015 Update 3 was released on 27 June 2016.
Initially referred to as Visual Studio "15", it was released on 7 March 2017. The first Preview was released on 30 March 2016. Visual Studio "15" Preview 2 was released 10 May 2016. Visual Studio "15" Preview 3 was released on 7 July 2016. Visual Studio "15" Preview 4 was released on 22 August 2016. Visual Studio "15" Preview 5 was released on 5 October 2016.
On 14 November 2016, for a brief period of time, Microsoft released a blog post revealing Visual Studio 2017 product name version alongside upcoming features.
On 7 March 2017, Visual Studio 2017 was released for general availability.
On 14 March 2017, first fix was released for Visual Studio 2017 due to failures during installation or opening solutions in the first release.
On 5 April 2017, Visual Studio 2017 15.1 was released and added support for targeting the .NET Framework 4.7.
On 10 May 2017, Visual Studio 2017 15.2 was released and added a new workload, "Data Science and Analytical Applications Workload". An update to fix the dark color theme was released on 12 May 2017.
On 14 August 2017, Visual Studio 2017 15.3 was released and added support for targeting .NET Core 2.0. An update (15.3.1) was released four days later to address a Git vulnerability with submodules (CVE 2017-1000117).
On October 10, 2017, Visual Studio 15.4 was released.
On December 4, 2017, Visual Studio 15.5 was released. This update contained major performance improvements, new features, as well as bug fixes.
On March 6, 2018, Visual Studio 15.6 was released. It includes updates to unit testing and performance.
Visual Studio 2017 offers new features like support for EditorConfig (a coding style enforcement framework), NGen support, .NET Core and Docker toolset (Preview), and Xamarin 4.3 (Preview). It also has XAML Editor, improved IntelliSense, live unit testing, debugging enhancement and better IDE experience and productivity.
This section needs expansion. You can help by adding to it. (June 2018)
On June 6 2018 Microsoft announced Visual Studio 2019 (version 16).
On 13 November 2013, Microsoft announced the release of a software as a service offering of Visual Studio on Microsoft Azure platform; at the time, Microsoft called it Visual Studio Online. Previously announced as Team Foundation Services, it expands over Team Foundation Server by making it available on the Internet and implementing a rolling release model. Customers could use Azure portal to subscribe to Visual Studio Online. Subscribers receive a hosted Git-compatible version control system, a load-testing service, a telemetry service and an in-browser code editor codenamed "Monaco". During the Connect(); 2015 developer event on 18 November 2015, Microsoft announced that the service name is changed to Visual Studio Team Services.
Microsoft offers Basic, Professional, and Advanced subscription plans for Team Services. The Basic plan is free of charge for up to five users. Users with an MSDN subscription of Visual Studio can be added to a plan with no additional charge.
Application Lifecycle Management
Visual Studio Application Lifecycle Management (ALM) is a collection of integrated software development tools developed by Microsoft. These tools currently consist of the IDE (Visual Studio 2015 Community and greater editions), server (Team Foundation Server), and cloud services (Visual Studio Team Services). Visual Studio ALM supports team-based development and collaboration, Agile project management, DevOps, source control, packaging, continuous development, automated testing, release management, continuous delivery, and reporting tools for apps and services.
In Visual Studio 2005 and Visual Studio 2008, the brand was known as Microsoft Visual Studio Team System (VSTS). In October 2009, the Team System brand was renamed Visual Studio ALM with the Visual Studio 2010 (codenamed 'Rosario') release.
Visual Studio Team Services debuted as Visual Studio Online in 2013 and was renamed in 2015.
Visual Studio LightSwitch
Microsoft Visual Studio LightSwitch is an extension and framework specifically tailored for creating line-of-business applications built on existing .NET technologies and Microsoft platforms. The applications produced are architecturally 3-tier: the user interface runs on either Microsoft Silverlight or HTML 5 client, or as a SharePoint 2013 app; the logic and data-access tier is built on WCF Data Services and exposed as an OData feed hosted in ASP.NET; and the primary data storage supports Microsoft SQL Server Express, Microsoft SQL Server and Microsoft SQL Azure. LightSwitch also supports other data sources including Microsoft SharePoint, OData and WCF RIA Services.
LightSwitch includes graphical designers for designing entities and entity relationships, entity queries, and UI screens. Business logic may be written in either Visual Basic or Visual C#. LightSwitch is included with Visual Studio 2012 Professional and higher. Visual Studio 2015 is the last release of Visual Studio that includes the LightSwitch tooling.
The user interface layer is now an optional component when deploying a LightSwitch solution, allowing a service-only deployment.
The first version of Visual Studio LightSwitch, released 26 July 2011, had many differences from the current[when?] release of LightSwitch. Notably the tool was purchased and installed as a stand-alone product. If Visual Studio 2010 Professional or higher was already installed on the machine, LightSwitch would integrate into that. The second major difference was the middle tier was built and exposed using WCF RIA Services.
As of 14 October 2016, Microsoft no longer recommends LightSwitch for new application development.
Visual Studio Code
Visual Studio Code is a source code editor, along with other features, for Linux, macOS, and Windows. It also includes support for debugging and embedded Git Control. It is open-source, and on 14 April 2016 was released as version 1.0.
Visual Studio Team System Profiler
Visual Studio Team System Profiler (VSTS Profiler) is a tool to analyze the performance of .NET projects that analyzes the space and time complexity of the program. It analyzes the code and prepares a report that includes CPU sampling, instrumentation, .NET memory allocation and resource contention.
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VLT infrared images reveal unexpected horde of low-mass objects
An international team has made use of the power of the HAWK-I infrared instrument on ESO's Very Large Telescope (VLT) to produce the deepest and most comprehensive view of the Orion Nebula to date. Not only has this led to an image of spectacular beauty, but it has revealed a great abundance of faint brown dwarfs and isolated planetary-mass objects. The very presence of these low-mass bodies provides an exciting insight into the history of star formation within the nebula itself.
This spectacular image of the Orion Nebula star-formation region was obtained from multiple exposures using the HAWK-I infrared camera on ESO's Very Large Telescope in Chile. This is the deepest view ever of this region and reveals more very faint planetary-mass objects than expected.
Credit: ESO/H. Drass et al.
The famous Orion Nebula spans about 24 light-years within the constellation of Orion (constellation), and is visible from Earth with the naked eye, as a fuzzy patch in Orion's sword. Some nebulae, like Orion, are strongly illuminated by ultraviolet radiation from the many hot stars born within them, such that the gas is ionised and glows brightly.
The relative proximity of the Orion Nebula makes it an ideal testbed to better understand the process and history of star formation, and to determine how many stars of different masses form.
Amelia Bayo (Universidad de Valparaíso, Valparaíso, Chile; Max-Planck Institut für Astronomie, Königstuhl, Germany), a co-author of the new paper and member of the research team, explains why this is important: "Understanding how many low-mass objects are found in the Orion Nebula is very important to constrain current theories of star formation. We now realise that the way these very low-mass objects form depends on their environment."
This new image has caused excitement because it reveals a unexpected wealth of very-low-mass objects, which in turn suggests that the Orion Nebula may be forming proportionally far more low-mass objects than closer and less active star formation regions.
Astronomers count up how many objects of different masses form in regions like the Orion Nebula to try to understand the star-formation process . Before this research the greatest number of objects were found with masses of about one quarter that of our Sun. The discovery of a plethora of new objects with masses far lower than this in the Orion Nebula has now created a second maximum at a much lower mass in the distribution of star counts.
These observations also hint tantalisingly that the number of planet-sized objects might be far greater than previously thought. Whilst the technology to readily observe these objects does not exist yet, ESO's future European Extremely Large Telescope (E-ELT), scheduled to begin operations in 2024, is designed to pursue this as one of its goals.
Lead scientist Holger Drass (Astronomisches Institut, Ruhr-Universität Bochum, Bochum, Germany; Pontificia Universidad Católica de Chile, Santiago, Chile) enthuses: "Our result feels to me like a glimpse into a new era of planet and star formation science. The huge number of free-floating planets at our current observational limit is giving me hope that we will discover a wealth of smaller Earth-sized planets with the E-ELT."
Nebulae such as the famous one in Orion are also known as H II regions to indicate that they contain ionised hydrogen. These immense clouds of interstellar gas are sites of star formation throughout the Universe.
The Orion Nebula is estimated to lie about 1350 light-years from Earth.
This information is used to create something called the Initial Mass Function (IMF) -- a way of describing how many stars of different masses make up a stellar population at its birth. This provides an insight into the stellar population's origins. In other words, determining an accurate IMF, and having a solid theory to explain the origin of the IMF is of fundamental importance in the study of star formation.
This research was presented in a paper entitled "The bimodal initial mass function in the Orion Nebula Cloud", by H. Drass et al., published in Monthly Notices of the Royal Astronomical Society.
The team is composed of H. Drass (Astronomisches Institut, Ruhr-Universität Bochum, Bochum, Germany; Pontificia Universidad Católica de Chile, Santiago, Chile), M. Haas (Astronomisches Institut, Ruhr-Universität Bochum, Bochum, Germany), R. Chini (Astronomisches Institut, Ruhr-Universität Bochum, Bochum, Germany; Universidad Católica del Norte, Antofagasta, Chile), A. Bayo (Universidad de Valparaíso, Valparaíso, Chile; Max-Planck Institut für Astronomie, Königstuhl, Germany) , M. Hackstein (Astronomisches Institut, Ruhr-Universität Bochum, Bochum, Germany), V. Hoffmeister (Astronomisches Institut, Ruhr-Universität Bochum, Bochum, Germany), N. Godoy (Universidad de Valparaíso, Valparaíso, Chile) and N. Vogt (Universidad de Valparaíso, Valparaíso, Chile).
ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become "the world's biggest eye on the sky".
Pontificia Universidad Católica de Chile / Astronomisches Institut, Ruhr-Universität Bochum
Santiago / Bochum, Chile / Germany
Universidad de Valparaíso / Max-Planck Institut für Astronomie
Valparaíso / Königstuhl, Chile / Germany
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Richard Hook | EurekAlert!
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences | <urn:uuid:d980da79-dd6b-4504-a061-8890973415e6> | 3.390625 | 2,242 | Content Listing | Science & Tech. | 32.640088 | 95,513,924 |
Foraging honey bees make unique research animals in part because they communicate in a language humans can decode, said University of Illinois entomology and neuroscience professor Gene Robinson, who led the study. After a successful hunt, a forager performs a highly stylized “dance” that tells her peers what direction to go to find the food, how good it is and how far away it is. The bee does a “round dance” if the food is close to home, while a “waggle dance” indicates it is farther away.
(You can watch a video of activity in the honey bee hive, including the dances here: http://www.youtube.com/watch?v=lE-8QuBDkkw&feature=player_embedded)
The new study used an established method for altering a honey bee’s perception of distance as she flew through a tunnel to gather food. Vertical stripes or a busy pattern on the tunnel walls can trick a bee into thinking she is traveling a greater distance, while horizontal stripes or a sparse pattern indicate a shorter distance – even though the tunnels are the exact same length. At the end of the flight, a researcher watches the honey bee dance to find out how far she thinks she flew.
“This is a great example of what you can learn if you are able to manipulate an animal to be able to tell you what it’s thinking,” Robinson said.
Using microarray analysis, which tracks the activity of thousands of genes at once, the researchers compared gene expression in the brains of bees that thought they had traveled shorter or longer distances. The team focused on two brain regions: the optic lobes, which process visual information, and the mushroom bodies, which integrate sensory information and have been implicated in learning and memory.
Some bees (labeled S®S bees) traveled the “short” distance repeatedly to get to the food, while others (the S®L bees) trained on the “short” distance and then were switched to the “long” distance tunnel. Brain gene expression differed between the groups. A total of 29 annotated genes (for which sequence, location in the genome and function are known) were “differentially regulated between the S®L and S®S bees, either in the optic lobes, mushroom bodies, or both,” the researchers wrote.
Surprisingly, the patterns of gene expression (which genes were turned up, down, on or off in response to the experience) were similar in both brain regions, Robinson said, suggesting that similar molecular pathways are involved in responding to distance information in different parts of the brain. The fact that gene activity changes in the mushroom bodies may indicate that some of the information is encoded in memory, he said, “which makes sense because bees need to remember their flight distance long enough to communicate it to hive-mates by dance language.”
This study adds a new dimension to the ongoing exploration of the socially responsive genome, Robinson said. The genome is not a static blueprint for life, as was once believed, he said. “Instead we see how responsive the genome is to environmental stimuli and especially socially relevant stimuli. Here is another piece of the world that the genome is responding to that we didn’t know about before.”This study was supported by the National Science Foundation and the Illinois Sociogenomics Initiative.
Editor’s note: Gene Robinson directs the Neuroscience Program and is a theme leader at the Institute for Genomic Biology at Illinois. To contact Robinson, call 217-265-0309; e-mail email@example.com. The paper, "Distance-responsive genes found in dancing honey bees," is available online.
Diana Yates | University of Illinois
World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
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17.07.2018 | Power and Electrical Engineering | <urn:uuid:c7255890-4ff1-4ad9-99ad-6abe00a6e2c5> | 3.78125 | 1,443 | Content Listing | Science & Tech. | 41.5579 | 95,513,937 |
Plastic water bottles. One of the biggest problems that we are facing today is the lack of recycling of these bottles. We see them as quick and easy for on the go travel but the planet see's them as toxic. Our land fills are filling up with these bottles just because most are too lazy to recycle them at the proper facility.
I recently found an article that directly relates to this problem and has a solution to it! This article (Koreans make plastics without fossil fuel chemicals) was posted on the front of cnn's website and caught my attention.
It seems that these Korean scientists have found a way to produce the polymer that is used in everyday plastic products like water bottles without using fossil fuel chemicals. This means that these plastic polymers are planet friendly and biodegradable! Currently, these types of polymers are being made from fossil fuel chemicals which of course are hurting the planet.
Although the article did not mention when these new polymers will start to be mass produced, it will be a huge defeat over the traditional plastics we are using today. I can't wait for the day when water bottles are actually not hurting the environment! | <urn:uuid:b8bbd632-5202-481a-9ecd-c0e29bddb7e4> | 2.84375 | 235 | Personal Blog | Science & Tech. | 50.821502 | 95,513,942 |
Call it weird, call it extreme, maybe even call it the new normal. Wild weather in the United States in the past decade has amassed a long list of toppled records and financial disasters.
Some of these exceptional weather events included unusually heavy rain and snow. Now, a new study confirms that everywhere except in the Atlantic Plains region, more rain and snow is falling during wet and dry seasons alike. The Atlantic Plains are the flatlands along the central and southern Atlantic Coast that stretch from Massachusetts to Mississippi. On average, the total precipitation in the contiguous United States has increased 5.9 percent, according to the U.S. Environmental Protection Agency.
What's more, the timing has changed too. In some parts of the United States, dry seasons are arriving earlier and wet seasons are starting later than they did 80 years ago. The time shift does not necessarily extend the length of dry or wet seasons, because most areas have transitional periods in between these precipitation extremes. In the Ohio River Valley, the fall dry season starts two to three weeks earlier today, the researchers report. In east New York, the wet season now kicks off on Jan. 8 instead of Feb. 1. And in the Southwest, the summer monsoon is starting later than it did during the middle of the 20th century. [In Images: Extreme Weather Around the World]
"The effects vary from region to region," said Indrani Pal, lead study author and a water resources engineer at the University of Colorado in Denver. "This study has a lot of implications from an ecology and water management perspective, and for extreme events like droughts and floods as well."
Flood conditions appear far worse in April 2011 than a year earlier, as the Wabash, Ohio, Black, and Mississippi Rivers are all considerably higher. Credit: NASA, MODIS Rapid Response Team, Goddard Space Flight Center.
Altering the timing of dry and wet season starts can significantly affect agriculture and cities, Pal said. In the Southwest, water contracts rely on the timing of spring snowmelt and summer monsoons to generate hydroelectric power and water for farming and millions of residents.
Pal and her colleagues analyzed data from 774 weather stations across the United States with a continuous record since 1930. They found an overall drop in dry spells (the number of days without precipitation) between 1930 and 2009 in most regions of the country. For instance, there were 15 more precipitation days (rain or snow) during the dry season in the Central and Great Plains, and 20 more precipitation days during the wet season in the Midwest and intermountain regions today than 80 years ago. However, the length of dry spells during the wet season, a drought indicator, increased by 50 percent in the Atlantic Plains.
Pal said the study cannot answer whether climate change is causing the seasonal shifts in precipitations. "This opens many other research doors," she told LiveScience. "We would like to find what is actually affecting this shift. It's probably a mixture of natural variability and climate change," Pal said.
The findings were published July 19 in the journal Geophysical Research Letters.
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Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. | <urn:uuid:1c277feb-c656-4cb7-99d6-23ce90d27b55> | 3.71875 | 696 | News Article | Science & Tech. | 48.347556 | 95,513,955 |
A team of researchers has prepared to study the Thwaites Glacier. Armed with the latest equipment, they aim to gather more data to support their claims that the cork glaciers are at risk.
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The results of a study conducted at Carnegie Mellon University propose that Google algorithms tend to discriminate against female job-seekers.
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Engineers at Binghamton University have developed an inexpensive method to produce foldable batteries made from paper. The new technology uses microbial respiration to generate enough power to operate a paper-based biosensor.
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Gravity waves could soon be detected by astronomers using the LIGO detectors. What could this teach us about the nature of the universe?
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Americans support science, and even enjoy hearing about discoveries and advancements in the fields of science and technology. So, why do so many remain ignorant of basic scientific facts?
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Photographs, illustrations, videos, and more demonstrating the beauty of science and nature have been judged by the National Science Foundation, the journal Science, and the public. Here are the winners.
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Simple “spin models” used to explain magnetism can precisely reproduce any possible phenomenon in classical, non-quantum physics, according to scientists at the MPQ and UCL.
This is the first time such simple ‘universal models’ have been found to exist. The study, published this week in Science, builds on pioneering work from the ‘80s which is at the interface between theoretical computer science and physics. Extremely simple computers are universal: they can in principle compute anything that can be computed. These new results show that something analogous occurs in physics.
Spin systems are a very simplified, stripped-down model of the interactions between particles making up a material. In the simplest of these models, each particle or “spin” can only be in one of two possible states: “up” or “down”. The interactions between neighbouring particles try to align them either in the same or in the opposite direction, which is known as the Ising model, after the physicist Ernst Ising who studied it in his 1924 PhD thesis.
“Models in different dimensions or with different kinds of symmetries show very different physical behaviour. Our study shows that if one considers models with irregular coupling strengths, all these differences disappear as they are all equivalent to universal models,” says Dr. Gemma De las Cuevas from the MPQ, Munich.
Previous work by Dr. De las Cuevas and others pointed the way, by showing something similar occurred for thermodynamic properties in more complicated models. This new work shows that the result holds for all of classical physics and for much simpler models. Moreover, by connecting the underlying physics to complexity theory – a branch of theoretical computer science – the results also explain where this universality comes from, and tell us exactly which models are universal and which are not.
“These results will perhaps not surprise computer scientists, who are used to the idea that universal computers can simulate anything, even other computers,” said co-author Dr Toby Cubitt from UCL Computer Science. “But the fact that a similar phenomenon occurs in physics is much more surprising, and this insight has not been applied in this way before. We are realising as a community that ideas from theoretical computer science can give us deep insights into physics, backed up by rigorous mathematical proofs. It’s a very exciting time to be working at the interface between these fields!”
He added, “This is not the same as the well-known phenomenon of ‘universality’ in statistical physics. In a sense, it’s the exact opposite. Universality explains why many different microscopic models all behave in the same way, whereas our universal models can behave in all kinds of different ways – in fact, in all possible ways!”
“Spin models are not only used in physics, but also to model other complex systems, such as neural networks, proteins or social networks. All these systems can be modeled by objects (such as neurons, aminoacids or persons) that are interconnected with and influenced by each other,” says De las Cuevas. The new results may hence allow to gain insights into these other systems too.
The researchers are now exploring whether their theoretical findings can be applied in practice to improve numerical simulations of many-body systems. Or to help engineer, in the laboratory, novel complex systems previously thought to be beyond the reach of current technology.
The research has been funded by the EU integrated project SIQS, the Royal Society (UK), and the John Templeton Foundation.
Gemma De las Cuevas and Toby S. Cubitt
Simple universal models capture all classical spin physics
Science, 11 March, 2016
Dr. Gemma de las Cuevas
Max Planck Institute of Quantum Optics
85748 Garching, Germany
Phone: +49 (0)89 / 32 905 - 343
Dr. Toby S. Cubitt
University College London
Department of Computer Science
66-72 Gower Street
London WC1E 6EA
Phone: +44 (0)20 3108 7158
Dr. Olivia Meyer-Sreng
Press & Public Relations
Max Planck Institute of Quantum Optics
85748 Garching, Germany
Phone: +49 (0)89 / 32 905 - 213
Dr. Olivia Meyer-Streng | Max-Planck-Institut für Quantenoptik
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Materials Sciences
18.07.2018 | Life Sciences
18.07.2018 | Health and Medicine | <urn:uuid:4e183555-8020-49fe-95f8-9a1d9ea1d065> | 3.328125 | 1,558 | Content Listing | Science & Tech. | 43.523169 | 95,513,979 |
All I want to do is to ask the user to keep inputting a "1" for tossing the coin. The program should keep a running total of how many "heads" and "tails". When the the user enters "2" the program should output the running total for both heads and tails.
As it codes now, the user is prompted only one time because I wanted to test for bugs and for logic errors, keeping it simple.
Here is my test class:
And here is my source class:
posted 8 years ago
NEVERMIND, I just figured out the answer to my question. Amazing how a cup of coffee will jolt the mind into powerdrive! :
I edited your post to have code tags. They preserve spacing and make code much easier to read. To use them yourself, you can click the button above where you type your post, the tags drop in, then paste your code between them.
Thanks, and welcome to the Ranch!
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors | <urn:uuid:885335d3-c69b-4be5-b90c-1fe969203358> | 2.96875 | 226 | Q&A Forum | Software Dev. | 67.201696 | 95,513,998 |
I've been going through some past papers and I've been losing marks for not using the correct number of significant figures in my answers. In maths, it was generally accepted that 3 sig figs were the most appropriate when necessary. However, in this physics course, it seems that they only want 2 sig figs most of the time.
Anybody know why this is? Should I definitely use 2 sig figs in the exam?
Turn on thread page Beta
Sig Figs in A2 OCR Physics B watch
- Thread Starter
- 28-01-2010 11:39
- 28-01-2010 13:36
This question comes up quite a lot. Some boards don't seem to have a consistent policy for physics.
The usual answer is that the result should have an "appropriate" number of sig figs.
"Appropriate" is determined by the number of sig figs in the data in the question. Strictly speaking, the data in the question should all be given to the same number of sig figs (3 usually) and you give your answer to the same. However, if the data is given to a mixture of 2 and 3 sig figs, you cannot meaningfully give your answer to a precision greater that the least number of sig figs in the data.
Part of the confusion is that people confuse "number of decimal places" with "number of significant figures". It is not the same thing.
Most of the boards I've looked at point out that certain calculations, such as those using atomic mass values to calculate mass deficit and thus energy in nuclear reactions, are given to 5 sig figs. The answer should be expressed accordingly.
Keep all intermediate values that are used later in the calculation to their maximum precision. | <urn:uuid:057d519e-6423-4f70-8246-afa4c20bcdfe> | 2.625 | 365 | Comment Section | Science & Tech. | 63.729058 | 95,514,009 |
Sergey Tarassov, (Canada) [email protected]
Weather prediction is a very complicated process dependent on various factors. Temperature, pressure, magnetic fields, sunspots, and human activity - everything has its part in the process of weather formation. Some of these can be described by corresponding differential equations; others are only an object of scientific observation. The influence of sunspots on life on Earth (including weather) is studied nowadays in different countries. But what about the cosmic neighbors of the Earth – the planets of our solar system and smaller cosmic objects? What if they also have some influence on the weather? Are there any correlations between these extraterrestrials and some processes on the Earth? Planets have some physical parameters that can be calculated, such as, their mass, velocity, parameters of their orbits, distances, etc. We propose some other approach that allows for taking into account any correlations between some weather parameters and some astronomical characteristics of the planets.
We are not alone in this thinking or the first in this field. There has been some research on the subject during past decades in different countries. Worth mentioning are the theoretical attempts of three great Russian thinkers of the Twentieth Century - Vernadsky, Tsiolkovsky and Chizhevsky. We also need to recognize the work of Dr. John Nelson for NASA (John Nelson, "Short-wave Radio Propagation Correlation with Planetary Positions" RCA Review, March 1951). Dr. Theodore Landscheidt made an overview of his research of solar activity in his books and articles.
We have spent many years trying to answer one simple question: are there any correlations between cosmic factors and different physical processes? If there are, what are they? It took us some years to create instruments for our research. Now we want to apply these instruments, i.e., our software programs, in some areas of our special interest. We have already used these programs in analyzing large data series. We have found that there are correlations between cosmic factors and some processes on the Earth. We have also found that such correlations are non-linear. But to find a correlation is not everything. The most important thing is to use this correlation for modeling and forecasting a real physical process. This article is our attempt to explain our approach to weather forecasting and the forecasting of sunspot activity.
We analyzed the time series for high temperatures in Hartford, Connecticut; data included the period from 1.1.1949 up to 7.31.1998 (18,000 research points). We chose this data only because of their availability. (We are willing to repeat this analysis for any other data set).
First of all, we prepared the data for the analysis. It means that for the research on temperature we take into account the annual trends and work with normalized temperatures.
Then we calculated planetary positions, their velocities, accelerations, distances and angles between planets, and some major asteroids, etc. all within the time interval that is defined by our data set.
The next step is to compare these two data sets in order to find any correlation. We used different modifications of regular statistical methods for this comparison.
And finally - we used the results of the previous step for the forecast. To perform this, we have developed a specialized neural network. This neural network works with a huge amount of data (for example, the specialized neural network for sunspot activity analysis has approximately 5000 inputs; we have used about 50000 points for the learning process). The reason behind using the neural network is in the nature of cosmic factors. We have found that their influence is non-linear (we will not show this in this article though it has been found in stock market analysis).
It is NOT a 100% forecast and we are not answering all questions about the process analyzed. We only humbly assume that it will help to add some more percentages to the accurate forecast made by various professionals in the field. Our approach is rather universal - it can be used for any data sets. Its purpose is finding correlations of the process analyzed and some cosmic (or extraterrestrial) factors.
One of the methods used for analysis is the Efficiency Test. The idea is very simple. We find the average parameter for: all dates when some cosmic factor occurs, all dates a day before and a day after this event, all dates two days before and two days after the event, all dates three days before and three days after, etc. We then put all these average meanings into a diagram that shows the changes of the parameter analyzed around the date of the cosmic event. It gives us an idea about possible correlations. Here we can make a hypothesis. Then we go back and simply count the number of times when such a hypothesis worked and when it does not. Thus, we arrived at a statistic for our data sample to help us to draw a conclusion about the hypothesis.
What do we do practically? We define the time interval for analysis and look for some cosmic factor within this interval. The "cosmic factor" could be a special position of some planet, some angle between two planets, some special cosmic pattern involving two or more planets or objects (for example, eclipse that involves the Sun, the Moon, the Earth), - anything that takes place in the space and can be described as a single, discreet event. This event occurs at some dates within the interval; it is our sample. For every single date of this sample, we normalize the parameter analyzed (i.e., temperature) around the date of the event, i.e., we mark the date when the cosmic event occurs as day "0"; we take the high temperature of this day as 0: [T(0)-T(0)=0]. The day before this event will be a day "-1". The high temperature of this day is taken according to the temperature of the day "0": [T(-1)-T(0)]. We do the same for a day after an event (day "1"), for two days before and after (days "-2" and "2"), three days, etc. We have tried even 10 days before and after the event, but the smaller intervals usually show the picture rather well. Then we take all temperatures for all days "0" and find their average (that is =0, of course); it is a central point of the diagram. After that we take temperatures for all days "1", calculate their average and put it into the diagram. We do the same for all days "2", "3", "4" ..., "-1", "-2", "-3", "-4" ... The results that are shown on a diagram allow us to make a hypothesis about the correlation between this cosmic event and the high daytime temperature.
For example, let us study such event as the change of the direction of planetary motion. Planets, of course, always move in the same direction inside the heliocentric coordinate system. Change of direction relates to geocentric system of coordinates. Within this system, the Earth is the center, and planets move around on different trajectories. To an observer somewhere on the Earth's surface, planets go in one direction (called direct motion), then move slower until they stop. After that, they go backwards (called retrograde motion), until the next stop. Then they renew their direct motion. We assume that it is worth a try to analyze the process happening on the Earth’s surface within the geocentric system of coordinates, and the important points of planetary trajectory within this system may give us some results.
To be more specific, we define the event researched as Venus becoming direct. The Efficiency Test for this event is shown here (Fig.1):
Fig.1. The Efficiency Test for Venus becoming direct; temperature drops.
This research has been done with the program "Market Trader Expert" developed for financial market analysis, and there are some financial symbols in the windows. We use this program to analyze other data sets, not only financial ones. So please - don't bother with all the prices and dollar signs, all necessary symbols will be explained.
The program has found that within the observed interval, Venus becomes direct 29 times. The temperature change distribution is shown on a histogram in the right part of the window. You can see that the temperature begins to drop 3 days before this event and goes up the next day after that. The temperature drop during 4 days (3 days before the event and a day after) is about 10% (comparing to the temperature of the day "0") and is shown by the blue arrow; it takes place 21 times and does not happen only 8 times.
Another arrow combines days when the temperature goes up after Venus becomes direct; it shows 20 up and 9 down (Fig.2).
Fig.2. The Efficiency Test for Venus becoming direct; temperature goes up.
Here we can make two hypotheses: 1) temperature drops three days before Venus becomes direct and a day after that; 2) temperature goes up the next day after Venus becomes direct. The first hypothesis is true 21 times from 29; the second hypothesis is true 20 times from 29. Looks like these hypotheses work quite well and we can use this hypothesis for weather forecasts. Dates when Venus becomes direct can be easily calculated astronomically, and next time when it will take place we can assume the temperature drops 3 days before the event and the temperature rises the following day. But our example has only 29 dates for analysis; it does not allow for a statistically reliable conclusion. We need to test this hypothesis with more data.
A similar research has been done for all points when Venus becomes retrograde (not shown here). In these cases, the temperature primarily goes up.
Now, let's take another event: Mercury becomes retrograde. The Efficiency Test for this event is shown on Fig.3:
Fig.3. The Efficiency Test for Mercury becoming retrograde.
According to this diagram (Fig.3), we can make a hypothesis: the temperature drops during 4 days after Mercury become retrograde. This event has occurred 146 times within the time interval researched. The hypothesis works 83 times and does not work 63 times out of the 146.
This result can be approved statistically; a chi-squared test of statistical significance (i.e. Pearson test) gives 1.369 amount for 1 degree of freedom and P=0.15. To continue the statistical analysis, we should test the hypothesis that such a correlation exists (i.e., a null hypothesis is that the temperature drops and ups are 50-50; a researched hypothesis is that the temperature goes down whenever Mercury becomes retrograde). We won't do that because of two considerations: 1) we are not sure that random temperature drops are 50% of all temperature changes; 2) we are doubtful that here we are dealing with the normal distribution, so we must use the methods of nonparametric statistics. Also, our research on financial markets shows that the cosmic factor correlations are non-linear. We propose another way: to create a working forecasting model instead of doing time-consuming statistical calculations; the Efficiency Test can be used only as an instrument to find some tendencies or an hypothesis that could (or could not) be true.
Efficiency Tests for other planetary directions are shown below (Fig.4, 5, 6). Some considerations on statistical results for these examples have been mentioned above.
Fig.4. The Efficiency Test for Jupiter becoming direct.
Here, the temperature goes down 2 days after Jupiter goes direct; it is true 29 times out of 42 (29 down/13 up).
Fig.5. The Efficiency Test for Saturn becoming direct.
The temperature goes up 4 days before Saturn becomes direct and then begins to drop; it is true for 27 times out of 45 (27 down/18 up).
Fig.6. The Efficiency Test for Mars becoming retrograde.
The temperature drops until the 4th day after Mars has become retrograde; it works 15 times out of 23 (15 down/8 up).
We can make the same analysis for any cosmic factor. Let's try now another one that involves position and distance between planets; for example, the 120-degree angle between Jupiter and Uranus (we take the distance as an angle, or the difference of the ecliptic longitudes for the two cosmic objects). Fig.7 shows the Efficiency Test for this event:
Fig.7. The Efficiency Test for 120-degree angle between Jupiter and Uranus.
Within the observed interval, this event happened 13 times. We assume (according to the Efficiency Test) that the temperature goes up two days after this event; the temperature goes up 11 times against just 2 drops. So, next time the angle between Jupiter and Uranus is 120 degrees (astronomers can tell us about that), we should suppose the temperature would go up the same day. (And it will drop 4 days before...). Some considerations on statistical results for this example have been mentioned above.
Above, we have shown results of the Efficiency Tests for just two types of cosmic factors: change of the direction of planetary motion and the angle between planets. For our data sample, some of them have correlations to the temperature change (temperature drops within three days before Venus becomes direct and goes up a day after that; temperature goes up during two days after reaching the exact angle between Jupiter and Uranus at 120 degrees); other correlations are not so obvious (temperature drops when Mercury becomes retrograde). We can take any cosmic event and check its correlation to temperature changes. But, as we have mentioned above, effect of cosmic factors on physical processes has a non-linear structure. One of the best methods to create a model of a non-linear system is a neural network.
According to Nikola K. Kasabov's book "Foundations of Neural Networks, Fuzzy Systems, and Knowledge Engineering" (The MIT Press, 1998), the neural network is "a biologically inspired computational model which consists of processing elements (called neurons) and connections between them with coefficients (weights) bound to the connections, which constitute the neuronal structure, and training and recall algorithms attached to the structure. Neural networks are called connectionist models because of the main role of the connections in them." The neural net studies the information about the process researched and adjusts it to the synaptic connections existing between the neurons. It is called the learning process. "Learning typically occurs by example through training, or exposure to a truthed set of input/output data where the training algorithm iteratively adjusts the connection weights (synapses). These connection weights store the knowledge necessary to solve the specific problems" (PNNL, Battelle Memorial Institute Bulletin).
We have developed our own special neural network (its type is a multi layer perceptron) that uses the astronomical factors as input neurons and gives the normalized temperature as output. But the universal structure of the neural networks allows for adding input other than astronomical factors.
The available data set (high temperature for Connecticut, 18,000 research points) has been divided onto two parts: the learning interval and testing interval. Points from Jan. 1, 1949 to Mar. 7, 1995 are used as a learning interval for the neural net; other points (Mar. 8, 1995 up to Jul. 31, 1998) serve to test these models.
The result is shown on Fig.8:
Here, the light green line is the normalized temperature; the dark green line shows the neural net's forecast. The vertical line for Mar 7 1995 is the bound between the learning interval and forecast. The closer to the bound, the more accurate the forecast is. Both green lines, light and dark, have the same time and ordinate scales; we estimate these lines visually. Here we need to use a correlation coefficient between a real physical process and neural net forecast. But it is not discussed here, because right now we are on the step of model searching; correlation coefficients are the next step.
Fig.9 and Fig.10 show the forecasts for the following dates:
Further results become chaotic (Fig.11, 12, and 13):
The farther from the bound, the lesser the accuracy. To make the forecast more accurate, the neural net should be learned on some new sets of data (i.e., we need to move the bound between learning and testing intervals from time to time).
We have some considerations upon the reasons of forecast fading through the time which can be discussed.
Beside the temperature, we have tried to analyze sunspot activity. We have some predecessors in this field:
"In summation, after more than 25 years of research in this field of solar system science, I can say without equivocation that there is very strong evidence that the planets, when in certain predictable arrangements, do cause changes to take place in those solar radiations that control our ionosphere. I have no solid theory to explain what I have observed, but the similarity between an electric generator with its carefully placed magnets and the Sun with its ever-changing planets is intriguing. In the generator, the magnets are fixed and produce a constant electrical current. If we consider that the planets are magnets and the Sun is the armature, we have a considerable similarity to the generator. However, in this case, the magnets are moving. For this reason, the electrical-magnetic stability of the solar system varies widely. This is what one would expect."
- John H. Nelson, RCA Communications. Cosmic Patterns. 1974.
"It is found empirically that solar activity is preceded by planetary conjunctions. A long-range prediction technique has been in use for 2.5 years, which predicts flares and proton events months in advance."
- J.B. Blizzard, Denver University. American Physical Society Bulletin #13, June 1968.
We have done some research on this correlation (planetary conjunctions) for sunspot activity data for the years 1849 - 2002 (August) presented by World Data Center for sunspot index. The data from 1848 to 1996 y.y. were used as a learning interval, other data - as a test of the forecast ability.
We began with the Efficiency Test. Here are some examples (Fig.14 and 15) exposing the correlation between planetary conjunctions and Sunspot activity:
Fig.14. Efficiency Test for Jupiter - Mars conjunction and sunspot activity index.
The Efficiency Test shows that for Jupiter - Mars conjunction (in heliocentric system) the sunspot activity index goes down 4 days before the conjunction and begins to rise at the day of the event. Within the interval observed, it has happen 43 times of 63 tries; it was not true 20 times. Some considerations on statistical results for this example have been mentioned above.
Fig.15. Efficiency Test for Jupiter - Mercury conjunction and Sunspot activity index.
Jupiter - Mercury conjunction (in heliocentric system) takes place more often than Jupiter - Mars. So here we have 625 points for analysis. The sunspot activity index goes down 4 days before the exact conjunction; it continues to go down two more days after, and during these two days the drop is bigger. So hypothesis in this case sounds as "The sunspot activity index goes down two days after the exact conjunction between Jupiter and Mercury takes place". This hypothesis works 380 times and does not work 245 times within the interval observed. This result is statistically approved. We tested it with null hypothesis. We could not choose a null hypothesis as "The sunspot activity index equally goes up and down" - because a simple observation of the diagram of this index shows equal change of the index, not amount of ups and downs. This index goes up fast (like receives some impulse) and then goes down slower. So we could not take the null hypothesis as 50% ups and downs. We did it this way: we chose 625 random points and created the Efficiency Test for this random data. Then we repeated this process for 625 other random points, five more times. Standard statistic methods for this random data show the average amounts of downs and ups as 340.6 and 284.4. It allows us to do the Pearson test for statistical significance and gives a chi-square amount as 4.5 and p=0.04; it means that the hypothesis about the sunspot activity index drop at the Jupiter - Mercury conjunction with a reliability of 96%. (If we take into account the dispersion of the Efficiency Test results, we have the reliability of this hypothesis 70% through 96%.)
If we take the opposition of Jupiter - Mercury, the Efficiency Test will show the rise of the sunspot activity index (Fig.16):
Fig.16. Efficiency Test for Jupiter - Mercury opposition and sunspot activity index.
Planets can form other angles between them, not a conjunction alone; some of these angles have a correlation to the sunspot activity index. We can continue to do the Efficiency Test for every possible angle between every possible pair of planets, or we can use another technique that is called “Composite." The idea behind these methods is to represent the data of the sunspot activity index in angular coordinates; then we look for a relationship between the sunspot activity index and the angle of some pair of planets. The composite for angle between Jupiter and Saturn (Fig.17) yields quite interesting results:
Fig.17. Composite for sunspot activity index as a function of the angle between Jupiter and Saturn.
The upper diagram shows how the sunspot activity index depends on the angle between Jupiter and Saturn (heliocentric system).
But again - all the above results must be tested for statistical reliability. Or we can use them all as a hypothesis that will be used as input for the neural network. The neural network for the sunspot activity index forecast gives us such results (Fig.18):
Fig.18. Neural net model for sunspot activity index.
Here, the diagram represents a normalized sunspot activity index (the light green line) and its forecast by the neural net (the dark green line). The vertical line is a border between learning and forecasting intervals; the neural net forecast can be seen after this border. The target function used here is (I - IMA10)/IMA500, where I stands for the Sunspot Index, and IMA10 and IMA500 stand for the moving average of the index within 10-days and 500-days intervals accordingly. We tried to receive the short-term forecast. In this case, the neural net uses heliocentric planetary angles as input.
Figs.18 and 19 through 22 show the results for different models and different neural net analysis for the sunspot activity index (the learning bound is May 26, 1995). These pictures illustrate our work in process.
Fig. 19. Another neural net model for sunspot activity index (continued on Fig. 19 - 21).
Fig. 20. Neural net model for sunspot activity index
Fig. 21. Neural net model for sunspot activity index
Fig. 22. Neural net model for sunspot activity index
As we have mentioned above, the nature of the impact of cosmic factors to the physical process is non-linear. A single factor (i.e., the angle between Mars and Venus) does not influence the same way all the time. It looks as if these single factors act as a complex. It means that the number of hidden neurons of the neural net is rather large and such a neural net takes a lot of time for learning. Now, we try to understand the following: a) what cosmic factors are more important for modeling a specific physical process (the standard techniques of finding the most significant factors like "boxing counting" cannot be used because of huge volume of input); b) how these factors should be formalized when they are used as neural network inputs (we use now Fuzzy NN mostly); c) what is the optimal structure of this neural network (number of neurons at the hidden layers and type of activation function). We continue our research on the subject. Solving the problem takes time because we try different models and hypothesis as variable inputs for the neural net. But even now we can be sure that the neural net exactly models the process of geomagnetic activity (or other physical processes - in other cases).
We created our neural net as an open system. It means that we can analyze any time series of data and use as input any parameters (not only astronomical) that are related to the process researched.
Correlations between extraterrestrial factors and physical processes on the Earth are reality nowadays. Methods described in this article allow investigating them. As it was mentioned above, we are not creating new physical models or theories for some real processes. It is a task for others. To our mind, one of the possible ways to explain how these correlations work is in minor variations of the gravity potential. It fits to the modern scientific paradigm (especially non-linear dynamics) and appeals to non-equilibrium processes at atmosphere boundary layers. But this is a theme for future discussion.
Besides, the neural net we have created works now as a black box: it takes data and finds the connection weights. We see results, but we don’t know exactly how every parameter works. There are some ways to extract the knowledge from the neural net; we work on it also trying to make this “black box” at least “a grey one”.
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The Earth's atmosphere shields life from deadly ultraviolet radiation from the sun and provides the planet with stable temperatures. It contains a number of layers, the most well known of which are the troposphere, stratosphere, mesosphere and thermosphere. The vast majority of the weather occurs in the troposphere, but some clouds can appear higher up in the stratosphere and mesosphere.
Life forms on the planet inhabit the troposphere, the lowest level of the atmosphere, which extends from the surface to between 7 and 20 kilometers (4 to 12 miles) above it. It creates almost all the known weather phenomena, and clouds that reside there generate rain, hail and snow. Stratus clouds are the lowest type found in the troposphere; they are often found at ground level as fog or mist. Displaying a dull gray appearance, they rarely produce any precipitation.
The stratosphere, where jetliners fly, can be found in the zone between 20 and 50 kilometers (12 to 31 miles) from the surface. Water vapor can only be found at a very low concentration in the stratosphere, making the presence of clouds very rare. Volcanic eruptions, however, can eject vast amounts of dust into the stratosphere, and this sometimes combines with ice particles to produce nacreous clouds that often have a colorful appearance.
The mesosphere can be found between 50 and 85 kilometers (31 to 53 miles) from the surface. Its position makes it very difficult for scientists to study, since it is too high for balloons or planes to fly in and yet too low for orbital spacecraft. This makes the mesosphere one of the most poorly understood regions of the atmosphere. Noctilucent clouds were found to exist within the mesosphere in the late 1800s. These special clouds only form when water vapor is released by methane in a chemical reaction. The increase in methane within the Earth's atmosphere has led to an increase in the observation of noctilucent clouds.
The thermosphere extends from 90 kilometers (56 miles) to between 500 and 1,000 kilometers (310 and 620 miles) above the Earth's surface. Although it is considered a part of the Earth's atmosphere, the air density is so low that it can be considered space. The International Space Station orbits within the thermosphere at an altitude of approximately 370 kilometers. No clouds are found within the thermosphere. | <urn:uuid:f4dcad72-4469-41e4-8071-df4866a94561> | 4.21875 | 483 | Knowledge Article | Science & Tech. | 43.423143 | 95,514,018 |
Community Contributor | Jul 3, 2018 | 0
What the El Nino Southern Oscillation means for us
El Nino and its driving force, the Southern Oscillation, are back in the news. Not because of their presence, but because of a possible resurgence. Should this occur, what would it mean for us?
The entire Namibia is climatically labelled as an arid country. As per this description, Namibia is the driest country in the maritime, southern hemisphere. Aridity means the deserts of the world will be found within this geographical range.
But Namibia has an identifiable rainfall season across “summer to autumn” – from January, February, March and with April as a useful addition in cooler conditions. Across the country, these four months would provide over 80% of the recorded rainfall totals, with statistics supporting those expectations across the individual stations’ rainfall history. So when any comment is made regarding weather/climate prospects for a given year, the focus will be on January to April first and foremost.
The remainder of the year has little practical meaning. This emphasizes a focus on both the overall farming/agricultural world and those who would have to support it should spasmodic rains or drought prevail.
With just over a century’s worth of daily data on hand, there is the realisation that ENSO-dominated years are drought-prone with heavier falls limited to a premium, wetter events similarly restricted or absent, the January to April range beleaguered.
The two most recent ENSO events, 2007 and 2010 for short, without the individual month range of influence, were both in the dry range. Climate change did see the northern quarter of Namibia enjoy a more ordered wet January to April range in 2010 but for the remainder (usually drier in any case) of the country, 2010 matched the dry scenario.
But elsewhere, 2010 gained another, differing aspect.
2010 saw an ENSO pattern at variance from the usual. Pressures did decrease at Tahiti, but Darwin lay for months beneath the Inter-Tropical Convergence Zone. With global warming, the southern hemisphere high pressure belt lay some 10 degrees further south. There has been little change from 2008 until our present 2012 with high barometer values equally consistent. This departure from normal was frequently remarked by the Australian commentators. Australia’s calendar 2010 saw widespread rains, breaking a 6-year dry to drought-ridden sequence, also from April La Nina trends were appearing, but not in control, in the Pacific. Their move currently is to dub 2010 as La Nina year, calendar year but that is based on their local conditions in that particular year.
For Namibia, 2010 is in the ENSO stable acknowledging the drier January to April records from central and southern Namibia. The danger of reclassifying 2010 lies not in the actual rainfall but in the perception, hence in forecasts based on the weather experience of that year.
Medium term forecasts are now generally in agreement that by the second half of this year, conditions in the Pacific Ocean will have returned to ENSO neutral. The implication is that there is a 50/50 chance for the Pacific to switch to El Nino by the end of the year. El Nino means drought for southern Africa but if the definition does not comfortably fit our local conditions it might as well just mean an average year.
Currently La Nina, although weaker than last year, is still in control as witnessed by the prominent north-south-north airflow. For us the remainder of the season will not be above average but as long as ENSO conditions are not neutral (yet), rainfall can continue up to the beginning of May. | <urn:uuid:5b9d374a-f67d-4819-9982-21aaa61fa5cc> | 3.125 | 761 | News Article | Science & Tech. | 44.879671 | 95,514,027 |
DropSynth can make thousands of genes at once for just a few dollars apiece
A new technique pioneered by UCLA researchers could enable scientists in any typical biochemistry laboratory to make their own gene sequences for only about $2 per gene. Researchers now generally buy gene sequences from commercial vendors for $50 to $100 per gene.
The approach, DropSynth, which is described in the January issue of the journal Science, makes it possible to produce thousands of genes at once. Scientists use gene sequences to screen for gene’s roles in diseases and important biological processes.
“Our method gives any lab that wants the power to build its own DNA sequences,” said Sriram Kosuri, a UCLA assistant professor of chemistry and biochemistry and senior author of the study. “This is the first time that, without a million dollars, an average lab can make 10,000 genes from scratch.”
Increasingly, scientists studying a wide range of subjects in medicine — from antibiotic resistance to cancer — are conducting “high-throughput” experiments, meaning that they simultaneously screen hundreds or thousands of groups of cells. Analyzing large numbers of cells, each with slight differences in their DNA, for their ability to carry out a behavior or survive a drug treatment can reveal the importance of particular genes, or sections of genes, in those abilities.
Such experiments require not only large numbers of genes but also that those genes are sequenced. Over the past 10 years, advances in sequencing have enabled researchers to simultaneously determine the sequences of many strands of DNA. So the cost of sequencing has plummeted, even as the process of generating genes has remained comparatively slow and expensive.
“There’s an ongoing need to develop new gene synthesis techniques,” said Calin Plesa, a UCLA postdoctoral research fellow and co-first author of the paper. “The more DNA you can synthesize, the more hypotheses you can test.”
The current methods for synthesizing genes, he said, either limit the length of a gene to about 200 base pairs — the sets of nucleotides that made up DNA — or are prohibitively expensive for most labs.
The new method involves isolating small sections of thousands of genes in tiny droplets of water suspended in an oil. Each section of DNA is assigned a molecular “bar code,” which identifies the longer gene to which it belongs.
Then, the sections, which initially are present in only very small amounts, are copied many times to increase their number. Finally, small beads are used to sort the mixture of DNA fragments into the right combinations to make longer genes, and the sections are combined. The result is a mixture of thousands of the desired genes, which can be used in experiments.
To show that technique worked, the scientists used DropSynth to make thousands of bacterial genes — each as long as 669 base pairs in length. Each gene encoded a different bacterium’s version of the metabolic protein phosphopantetheine adenylyltransferase, or PPAT, which bacteria need to survive. Because PPAT is critical to bacteria that cause everything from sinus infections to pneumonia and food poisoning, it’s being studied as a potential antibiotic target.
The researchers created a mixture of the thousands of versions of PPAT with DropSynth, and then added each gene to a version of E. coli that lacked PPAT and tested which ones allowed E. coli to survive. The surviving cells could then be used to screen potential antibiotics very quickly and at a low cost.
DropSynth could potentially also be useful in engineering new proteins. Currently, scientists can use computer programs to design proteins that meet certain parameters, such as the ability to bind to certain molecules, but DropSynth could offer researchers hundreds or even thousands of options from which to choose the proteins that best fit their needs.
The team is still working on reducing DropSynth’s error rate. In the meantime, though, the scientists have made the instructions publicly available on their website. All of the chemical substances needed to replicate the approach are commercially available.
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WASHINGTON, Sept. 19 - Combining an old concept, existing equipment and new ideas, NASA gave shape on Monday to President Bush's promise to send humans back to the Moon by the end of the next decade.
Michael D. Griffin, the agency's new administrator, detailed a $104 billion plan that he said would get astronauts to the Moon by 2018, serve as a steppingstone to Mars and beyond, and stay within NASA's existing budget.
The plan would use a new spacecraft similar to the Apollo command capsule of the original Moon program, and new rockets made up largely of components from the space shuttle program.
"It is very Apollo-like," Dr. Griffin said, "but bigger. Think of it as Apollo on steroids."
The plan drew a mixture of praise and criticism from lawmakers and space experts. [News analysis, Page A15.]
The chairman of the House Science Committee, Representative Sherwood Boehlert, Republican of New York, said it appeared to be "the safest, least expensive and most efficient way" of moving forward in space exploration, but added that current cost overruns in other NASA programs might make it hard to develop the new vehicle on schedule.Continue reading the main story
The outlines of the plan had been disclosed informally over the last two months by NASA officials and space experts. But Dr. Griffin's announcement laid out a timetable and a budget, putting flesh on the bones of a proposal that Mr. Bush announced in January 2004 but had never described in detail.
Dr. Griffin said that after adjusting for inflation, the program would cost just 55 percent of what it cost to put a dozen men on the lunar surface from 1969 to 1972.
The pay-as-you-go plan, approved by the White House last week, would stay within NASA's $16-billion-a-year budget through a combination of retiring the space shuttle, finishing the International Space Station and reallocating money from other NASA programs. And Dr. Griffin said the nation could well afford it, despite concern about tight budgets in the wake of Hurricane Katrina.
"We're talking about returning to the Moon in 2018," he said at a news conference here in Washington. "There will be a lot more hurricanes and a lot more other natural disasters to befall the United States and the world in that time, I hope none worse than Katrina.
"But the space program is a long-term investment in our future. We must deal with our short-term problems while not sacrificing our long-term investments in our future. When we have a hurricane, we don't cancel the Air Force. We don't cancel the Navy. And we're not going to cancel NASA."
Dr. Griffin and other space advocates, including influential members of Congress, have said the United States needs a replacement for the aging shuttle fleet as a matter of national security. Russia and China are currently capable of human spaceflight, and other countries have expressed interest in following suit. Dr. Griffin said the nation must maintain an independent capability to send people into space after the shuttle retires in 2010.
The new craft, called the crew exploration vehicle, would perch the astronauts' capsule above the rockets that power it into space, rather than alongside them as with the shuttle. NASA officials said it would be 10 times as safe as the shuttle, with a projected failure rate of 1 in 2,000, as opposed to 1 in 220 for the shuttle. The increased safety, they said, will be due in part to escape rockets that will be able to jettison the capsule away from the booster rocket in the event of an accident.
Dr. Griffin said the vehicle would be able to take as many as six astronauts to the space station, or fewer astronauts and some cargo. Or it could fly robotically without a crew, he added, carrying up some 25 tons of cargo, about as much as a shuttle can carry. The wingless craft, weighing 50 percent more than the Apollo, could carry a crew of four to the Moon.
As envisioned, the craft would resemble a larger version of the Russian spacecraft Soyuz, including solar-power panels deployed after launching. It would be carried aloft on a modified version of one of the shuttle's solid-fueled rocket boosters and a new second stage using one of the shuttle's main liquid-fueled engines. For Moon voyages, the craft would rendezvous in Earth orbit with lunar components lifted on a big new cargo rocket.
This heavy-cargo rocket, which could put 125 tons into orbit, would comprise two extended shuttle solid-fuel boosters attached to a liquid hydrogen-oxygen first stage made of an extended shuttle external fuel tank with five shuttle main engines. Atop this would be a new second stage using one or more of the shuttle main engines.
The bigger rocket, capable of lifting the payload of the Saturn V, which sent men to the Moon decades ago, would put into Earth orbit another rocket that could carry a landing craft and the crew vehicle to the Moon.
The Moon mission would be accomplished in stages. First, a vehicle with a lunar lander and a Moon rocket would be launched into Earth orbit. The crew capsule would be launched as much as a month later and would meet the first vehicle in orbit.
The joined craft would then be propelled to lunar orbit. From there, the landing craft would fly to the surface, and its crew of four would spend up to a week exploring.
Afterward, the top part of the two-piece lander would take the crew back to lunar orbit to rendezvous with the crew vehicle, which would have been left there unmanned, for the trip back to Earth. The bottom part of the lander could be left behind with equipment that might be used by future crews that land nearby, the agency said.
Nearing Earth, the crew vehicle would jettison its equipment module before the crew capsule plunged into the atmosphere. Parachutes would slow the capsule before it landed in the water or on land, possibly at Edwards Air Force Base in California. The landing would be cushioned by air bags on the craft's bottom or small rockets that fire just before touchdown.
Some of the big military contractors that stand to win multibillion-dollar contracts to launch and maintain the new mission vehicles said they were pleased by Monday's announcement.
"This is a big deal for us," said Michael Coats, chief of space exploration for the nation's largest military contractor, the Lockheed Martin Corporation, one of two teams competing to build the crew exploration vehicle. "Today's announcement means that we will have a stable program for a while. It would be great for us to compete and win a piece of the business."
Lockheed is the leader of a consortium that currently has a $28 million contract to design the crew exploration vehicle. Another team, headed by the Boeing Company and Northrop Grumman, has an identical contract to design an alternative. NASA is expected to select the winning design next spring.
John E. Pike, a space policy expert with the consulting firm GlobalSecurity.org, said NASA needed to sell more people on the value of a Moon program if it is to preserve future budgets and continue space exploration. The Moon may be a source of the rare element helium-3, for instance, which could fuel fusion reactors to provide abundant electricity on Earth, he said.
"NASA," Mr. Pike said, "needs to have reasons like this to go back to the Moon so the program has more stakeholders who see its value and want to protect it."Continue reading the main story | <urn:uuid:43bd0a3b-55dc-4e40-8cf1-6f4f917ebffd> | 2.546875 | 1,547 | Truncated | Science & Tech. | 54.087973 | 95,514,059 |
Scientists capture massive iceberg breaking — and it comes with a serious reminder
Recently published by the university, the footage shows an approximately 6.4-kilometre-long chunk of ice breaking off the Helheim Glacier.
It was captured by NYU scientists David and Denise Holland around 11:30 p.m. local time on June 22, while they were on a research expedition.
“We were almost ready to go to bed, we were closing down the camp and getting ready to go to sleep,” Denise, who works at NYU’s Environmental Fluid Dynamics Laboratory, recounted to Global News.
“I heard a noise that lasted longer than normal, sort of a loud booming sound.”
WATCH: Italian concert pianist plays atop melting ‘iceberg’ in the Arctic Ocean
She immediately turned on her camera and captured the event, which she explained is not necessarily rare in itself — but capturing it is.
“It’s rare that people are in the right place for such a large event with cameras pointed. We were really fortunate and quite amazed.”
The resulting iceberg, according to the university, is about the size of “lower Manhattan up to Midtown in New York City.”
But the scientists say it sheds light on something far more serious.
David, who is a professor of mathematics at NYU, explained that the breaking of ice from glaciers is known as calving and it contributes to rising sea levels.
WATCH: NASA images provide new look at iceberg which broke off Larsen C ice shelf
“In the video, you can actually see how the sea level changes,” David said in an interview. “When ice falls, it’s like adding an ice cube to a glass of water.”
The video was recorded over a span of 30 minutes, but condensed to less than two minutes by the university.
It shows one large piece of ice travel into the water, as well as several smaller portions known as “pinnacle bergs.”
David added that Greenland is an ideal place to study such issues, but other places on the planet are more of a threat to global sea levels as climate change occurs.
“The same process is happening down south in Antarctica and the scales are very much larger,” he said. “There sea-level change can actually have a very, very large impact on the planet.”
According to NASA’s National Snow and Ice Data Center, the mass of Greenland’s ice sheet “rapidly declined” between 2002 and 2016. Much of that was due to surface melting and iceberg calving.
WATCH: Scientists heading on expedition to Antarctica to view new ecosystem following iceberg’s split from ice shelf
Greenland shed about 280 gigatons of ice yearly during the period, and it led to the global sea level rising by 0.08 millimetres each year.
Greenland holds most of the world’s Arctic ice, but it’s not just Greenland’s glaciers that are predicted to contribute to rising sea levels.
A 2017 study by glaciologists at the University of California, Irvine (UCI) found that Canada’s glaciers have become a major contributor to sea-level changes.
The Queen Elizabeth Islands, which include Ellesmere Island and dozens more, saw surface melt on ice caps and glaciers accelerate by 900 per cent over the course of a decade.
It went from three gigatons per year in 2005 to 30 gigatons per year in 2015, the research showed.
Rising sea levels have a number of consequences on human life, especially those living in coastal areas. It also puts the habitats of wildlife in danger.
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the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky. Although its motion is not readily apparent, the entire galaxy is rotating about the Milky Way's center. Relative to the universe, the galaxy is moving at a speed of c.370 mi per sec (c.590 km per sec) in the same direction that the constellation Leo lies relative to the earth; it is also moving at c.60 mi per sec (c.100 km per sec) relative to the center of mass of the Local Group of galaxies. The sun, traveling at a speed of c.150 mi per sec (c.240 km per sec) in a nearly circular orbit, takes some 230 million years to complete one revolution.
Among the constellations the Milky Way passes through are Carina, Crux (the Southern Cross), Sagittarius (where it is brightest), Scorpius, Aquila, Cygnus, Perseus, Cassiopeia, Auriga, and Gemini. In the direction of Cygnus is the Great Rift, a band of dark matter that lies along the Milky Way, dividing it into two forks. Another dark region is the Coalsack, in Crux. Once believed to be vast empty regions in space, these dark areas are now known to be clouds of dark matter blotting out the light behind them. Such nonluminous clouds of dust and gas, called dark nebulae, obscure many parts of the sky from sight; in the direction of the galactic center, the view is almost entirely obscured.
The Milky Way is a large barred spiral galaxy comprising an estimated 200 billion stars (some estimates range as high as 400 billion) arrayed in the form of a disk, with a central elliptical bulge (some 12,000 light-years in diameter) of closely packed stars lying in the direction of Sagittarius. It is surrounded by a flat disk marked by six spiral arms that project from a dense, elongated concentration of stars, or bar, that runs through the bulge—four major and two minor—which wind out from the nucleus like a giant pinwheel. Our sun is situated in one of the smaller arms, called the Local or Orion Arm, that connect the more substantial next inner arm and the next outer arm. The sun lies roughly 27,000 light-years from the center of the galaxy, and in the galactic plane. When we look in the plane of the disk we see the combined light of its stars as the Milky Way. The diameter of the disk is c.100,000 light-years; its average thickness is 10,000 light-years, increasing to 30,000 light-years at the nucleus.
Certain features of the region near the sun suggested that our galaxy resembles the Andromeda Galaxy. In 1951 a group led by William Morgan detected evidence of spiral arms in Orion and Perseus. Another bright arm stretches from Sagittarius to Carina in the southern sky. With the development of radio astronomy, scientists have extended a nearly complete map of the spiral structure of the galaxy by tracing regions of hydrogen that dominate the spiral arms. The development of telescopes that could be placed in orbit led by 2005 to confirmation that the Milky Way was a barred spiral galaxy, not a spiral one as had been believed.
Surrounding the galaxy is a large spherical halo of globular star clusters that extends to a diameter of about 130,000 light-years; this is called the stellar halo. The galaxy also has a vast outer spherical region called the corona, or dark halo, which is as much as 600,000 light years in diameter and, in addition to dark matter which accounts for most of the Milky Way's mass, includes some distant globular clusters, the two nearby galaxies called the Magellanic clouds, and four smaller galaxies.
The stars, gas, and dust that make up the Milky Way can be grouped into two broad stellar populations that suggest how the galaxy evolved. The spiral arms and central plane of the Milky Way contain the interstellar gas, cosmic dust, and bright young stars categorized as Population I. The halo, spaces between the spiral arms, and central core of the galaxy contain the older, less spectacular stars that are categorized as Population II. This distribution can be explained by an evolutionary model in which an enormous cloud of gas and dust began to condense to form what are now Population II stars. The remaining gas and dust then collapsed, either suddenly or in stages, into the relatively thin disk in which Population I stars were (and still are being) formed.
Like other galaxies, the Milky Way is growing by absorbing small satellite galaxies. It is currently merging with the Large and Small Magellanic Clouds, a process that will be completed in about 100 million years. In 2003 a previously unknown galaxy was found to be colliding with the Milky Way. Its distinctive red stars are slowly being pulled into the Milky Way, and the dwarf will soon lose all its structure. Called the Canis Major dwarf galaxy after the constellation in which it lies, it is about 25,000 light years away from the solar system and 42,000 light years from the center of the Milky Way. This is closer than the Sagittarius dwarf galaxy, discovered in 1994, which is also colliding with the Milky Way. Several other galaxies are also, apparently, on a collision course with the Milky Way. The biggest and most spectacular collision will be with the Andromeda Galaxy. In about 2 billion years, massive tidal gravitational effects will tear spiral arms apart and start to shred the pinwheels from the outside in. The result will be an elliptical rather than a spiral Milky Way.
- See Alfaro, E. J.;Delgado, A. J., The Formation of the Milky Way (1995).
- The Milky Way (2002). ,
Faint luminous band that encircles the sky at an angle of about 63° to the celestial equator. It is irregular and patchy and varies from about...
The diffuse band of light that is seen, on a clear moonless night, stretching across the sky. It is composed of innumerable stars that are too...
Grouping of millions or billions of stars, held together by gravity. There are billions of galaxies in the universe. There are different types, inclu | <urn:uuid:1705966c-d6b3-4908-9d8b-062fb78e4741> | 3.734375 | 1,318 | Content Listing | Science & Tech. | 58.326234 | 95,514,072 |
At the same time, a little bit of warming may actually move certain organisms, particularly insects, in the high latitudes closer to their optimal temperature, the researchers say.
"In the tropics, most of the organisms we have studied, from insects to amphibians and reptiles, are already living at their optimal physiological temperatures," said Curtis Deutsch, UCLA assistant professor of atmospheric and oceanic sciences and co-author of the study. "When warming starts, they do less well as they move toward the hottest end of their comfort range. Even a modest increase in temperature appears rather large to them and negatively impacts their population growth rates."
Why should we be concerned with the fate of insects in the tropics?
"The biodiversity of the planet is concentrated in tropical climates, where there is a tremendous variety of species," Deutsch said. "This makes our finding that the impacts of global warming are going to be most detrimental to species in tropical climates all the more disturbing. In addition, what hurts the insects hurts the ecosystem. Insects carry out essential functions for humans and ecosystems — such as pollinating our crops and breaking down organic matter back into its nutrients so other organisms can use them. Insects are essential to the ecosystem."
At least for the short term, the impact of global warming will have opposing effects. In the tropics, warming will reduce insects' ability to reproduce; in the high latitudes, the ability of organisms to reproduce will increase slightly, Deutsch said. If warming continues, the insects in the high latitudes would eventually be adversely affected as well.
"Our results imply that in the absence of any adaptation or migration by these populations in the tropics, they will experience large declines in their population growth rate," Deutsch said. "This could lead to a fairly rapid population collapse, but organisms are adaptable; the question is, what will their response be? They could migrate toward the poles or toward higher elevations, for instance."
"We don't think this is restricted to insect species," Deutsch said. "Data on turtles, lizards, frogs and toads show patterns that are very similar to what we find for insects. They will do much worse in the tropics than in the high latitudes."
Scientists have measured in laboratories how sensitive different species are to changes in temperature. For insects, the data is comprehensive and includes information on how temperature affects the population growth rate for species, Deutsch said. He and his colleagues — who included Joshua Tewksbury, assistant professor of biology at the University of Washington, and Raymond Huey, professor of biology at the University of Washington — studied the data, then went to climate models and analyzed what the predicted temperature change in various regions implied about species' future growth rate.
According to climate predictions, more rapid rates of warming of the Earth's surface will occur in the higher latitudes, especially in the polar regions, than at the equator, Deutsch said.
"You would think a larger warming in Alaska would have a greater impact on the organisms living there than a much smaller increase in, say, Panama or Costa Rica," he said. "We found the opposite will be true. A 1-degree temperature change in Panama will not be felt the same way by an organism as a 1-degree temperature change in Alaska."
The range of temperature tolerance that an organism has is largely dependent on how much temperature variability it experiences. In the tropics, the amount of temperature variability is very small; there is little difference between summer and winter, while in Alaska, the seasons are dramatically different.
To live in their environments, organisms in the tropics should have a relatively narrow tolerance for temperature change, while in the high latitudes, organisms should be able to tolerate a much wider variation in temperature.
"The magnitude of the impact of global warming depends largely on what we do to slow it down," Deutsch said.
Stuart Wolpert | EurekAlert!
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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What Is the Progress Towards Understanding the Selection Webs Influencing Melanic Polymorphisms in Insects?
Industrial melanism refers to a correlation between high frequencies of melanic forms of an insect and regions of industrialization. This phenomenon in the peppered moth Biston betularia (L.) is the classic textbook example of the evolution of an adaptive trait in response to a changing environments involving the spread of adapted pheno-types by natural selection. The accounts include information about the central hypothesis of a change in the relative crypsis of non-melanic and melanic phenotypes due to blackening of the resting background of the moths by industrial air pollution. The entomologist, J.W. Tutt, writing at the end of the last century, presented particularly graphic descriptions of the essential features of this hypothesis (e.g. Tutt 1896). We can now ask: how much further have we actually progressed in our understanding since then and what has the theory of population genetics contributed to this understanding?
KeywordsVisual Selection Foliose Lichen Fruticose Lichen Melanic Form Pepper Moth
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- Shellard HC (1976) Wind. In: Chandler TJ, Gregory S (eds) The climate of the British Isles. Longman, London New York, pp 39–73Google Scholar
- Tutt JW (1896) British moths. RoutledgeGoogle Scholar | <urn:uuid:617dc39e-1f8b-4069-bff2-0ae55f56bcf4> | 2.65625 | 875 | Truncated | Science & Tech. | 43.611746 | 95,514,100 |
In a paper published online on April 25 in the journal Physical Review D, the two physicists show that matter as we know it will remain as the universe expands at an ever-increasing clip. That is, the current status quo between matter and its alter ego, radiation, will continue as the newly discovered force of dark energy pushes the universe apart.
“Diamonds may actually be forever,” quips Krauss, professor of physics and astronomy at Case Western Reserve University (CWRU) who is spending the year at Vanderbilt. “One of the only positive things that has arisen from the dark-energy dominated universe is that matter gets to beat radiation forever.”
This viewpoint runs contrary to conventional wisdom among cosmologists. Today, there is more matter than radiation in the universe. But there were periods during the early universe that were dominated by radiation due to particle decays. The generally accepted view of the distant future has been that ordinary matter particles – protons and neutrons in particular – will gradually decay into radiation over trillions upon trillions of years, leaving a universe in which radiation once again dominates over matter; a universe lacking the material structures that are necessary for life.
It is only in the last decade that the existence of dark energy has been recognized. Before that Krauss and collaborators argued for its existence based on indirect evidence, but the first direct evidence came in 1998 when a major survey of exploding stars, called supernovae, revealed that the universe is apparently expanding at an increasing rate. Dark energy acts as a kind of anti-gravity that drives the expansion of the universe at large scales. Because it is associated with space itself, it is also called “vacuum energy.” A number of follow-up observations have supported the conclusion that dark energy accounts for about 70 percent of all the energy in the universe.
“The discovery of dark energy has changed everything, but it has changed the view of the future more than the past. It is among the worst of all possible futures for life,” says Krauss, who has spent the last few years exploring its implications. In an eternally expanding universe there is at least a chance that life could endure forever, but not in a universe dominated by vacuum energy, Krauss and CWRU collaborator Glenn Starkman have concluded.
As the universe expands, the most distant objects recede at the highest velocity. The faster that objects recede, the more that the light coming from them is “red-shifted” to longer wavelengths. When their recessional velocity reaches light speed, they disappear because they are traveling away faster than the light that they emit. According to Krauss and Starkman, the process of disappearance has already begun: There are objects that were visible when the universe was half its present age that are invisible now. However, the process won’t become really noticeable until the universe is about 100 billion years old. By ten trillion years, nothing but our local cluster of galaxies will be visible.
From the perspective of future civilizations, this process puts a finite limit on the amount of information and energy that will be available to maintain life. Assuming that consciousness is a physical phenomenon, this implies that life itself cannot be eternal, Krauss and Starkman argue.
“Our current study doesn’t change the process, but it does make it a little friendlier for matter and less friendly for radiation,” says Scherrer, professor of physics at Vanderbilt.
In their paper, Krauss and Scherrer analyzed all the ways that ordinary matter and dark matter could decay into radiation. (Dark matter is different from dark energy. It is an unknown form of matter that astronomers have only been able to detect by its gravitational effect on the ordinary matter in nearby galaxies.
At this point, the physicists have no idea whether it is stable or will ultimately decay like ordinary matter.) Given known constraints on these various decay processes, the two show that none of them can produce radiation densities that exceed the density of the remaining matter. This is counter-intuitive because, when matter turns into energy, it does so according to Einstein’s equation, E=mc2, and produces copious amounts of energy.
“The surprising thing is that radiation disappears as fast as it is created in a universe with dark energy,” says Krauss.
The reason for radiation’s vanishing act involves the expansion of space. Expanding space diminishes the density of radiant energy in two ways. The first is by increasing the separation between individual photons. The second is by reducing the amount of energy carried by individual photons. A photon’s energy is contained entirely in its electromagnetic field. The shorter its wavelength and the higher its frequency, the more energy it contains. As space itself expands, the wavelengths of all the photons within it lengthen and their frequency drops. This means that the amount energy that individual photons contain also decreases. Taken together, these two effects dramatically reduce the energy density of radiation.
Protons and neutrons, by contrast, only suffer from the separation effect. Most of the energy that they carry is bound up in their mass and is not affected by spatial expansion. In an accelerating universe, that is enough of an advantage to maintain matter’s dominance - forever.
The research was funded by grants from the National Science Foundation and the U.S. Department of Energy.
David Salisbury | Vanderbilt University
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences | <urn:uuid:8c921b76-dedb-443a-9c4d-9b4600ce5e57> | 3.34375 | 1,682 | Content Listing | Science & Tech. | 36.858416 | 95,514,106 |
Methods and Applications
Two geostatistical approaches are traditionally used to build numerical models of facies spatial distributions: the variogram-based approach and the object-based approach. Variogram-based techniques aim at generating simulated realizations that honor the sample data and reproduce a given semivariogram that models the two-point spatial correlation of the facies. However, because the semivariogram is only a measure of linear continuity, variogram-based algorithms give poor representations of curvilinear or geometrically complex actual facies geometries. In contrast, object-based techniques allow modeling crisp geometries, but the conditioning on sample data requires iterative trial-and-error corrections that can be time consuming, particularly when the data are dense relative to the average object size. This chapter presents an alternative approach that combines the easy conditioning of pixel-based algorithms with the ability to reproduce shapes of object-based techniques, without being too time and memory demanding.
In this new approach, the geological structures believed to be present in the subsurface are characterized by multiple-point statistics, which express joint variability or joint continuity at many more than two locations at a time. Multiple-point statistics cannot be inferred from typically sparse sample data, but they can be read from training images depicting the expected patterns of geological heterogeneity. Training images are simply graphical representations of a prior geological or structural concept; they need not carry any locally accurate information about the field to be modeled. The multiple-point patterns borrowed from the training image(s) are exported to the model, where they are anchored to the actual subsurface data, both hard and soft, using a pixel-based sequential simulation algorithm.
This multiple-point statistics simulation algorithm is tested on the modeling of a fluvial hydrocarbon reservoir where flow is controlled by meandering sand channels. The simulated numerical model reproduces channel patterns and honors exactly all well data values at their locations. The methodology proposed appears to be easy to apply, general, and fast. | <urn:uuid:aea23eda-36da-48b4-ba70-56f49ce77238> | 2.546875 | 408 | Academic Writing | Science & Tech. | 3.054085 | 95,514,133 |
Researchers from Nexus Spine LLC and Brigham Young University have Developed New, High-Tech Device for Transferring DNA into Cells
The ability to transfer a gene or DNA sequence from one animal into the genome of another plays a critical role in a wide range of medical research—including cancer, Alzheimer’s disease, and diabetes.
This SEM (scanning electron microscope) image shows the nanoinjector next to a latex bead the same size as an egg cell. You can see the size of the nanoinjector and its lance compared to a cell.
But the traditional method of transferring genetic material into a new cell, called “microinjection,” has a serious downside. It involves using a small glass pipette to pump a solution containing DNA into the nucleus of an egg cell, but the extra fluid can cause the cell to swell and destroy it—resulting in a 25 to 40 percent cell death rate.
Now, thanks to the work of researchers from Brigham Young University, there’s a way to avoid cell death when introducing DNA into egg cells. In Review of Scientific Instruments, the team describes its microelectromechanical system (MEMS) nanoinjector, which was designed to inject DNA into mouse zygotes (single-cell embryos consisting of a fertilized egg).
“Essentially, we use electrical forces to attract and repel DNA—allowing injections to occur with a tiny, electrically conductive lance,” explained Brian Jensen, associate professor in the Department of Mechanical Engineering at Brigham Young University. “DNA is attracted to the outside of the lance using positive voltage, and then the lance is inserted into a cell.”
The MEMS nanoinjector’s lance is incredibly small and no extra fluid is used with this technique, so cells undergo much less stress compared to the traditional microinjection process.
This ability to inject DNA into cells without causing cell death leads to “more efficient injections, which in turn reduces the cost to create a transgenic animal,” according to Jensen.
One of the team’s most significant findings is that it’s possible to use the electrical forces to get DNA into the nucleus of the cell—without having to carefully aim the lance into the pronucleus (the cellular structure containing the cell’s DNA). “This may enable future automation of the injections, without requiring manual injection,” Jensen says.
It may also mean that injections can be performed in animals with cloudy or opaque embryos. “Such animals, including many interesting larger ones like pigs, would be attractive for a variety of transgenic technologies,” said Jensen. “We believe nanoinjection may open new fields of discovery in these animals.”
As a next step, Jensen and colleagues are performing injections into cells in a cell culture using an array of lances that can inject hundreds of thousands of cells at once. “We expect the lance array may enable gene therapy using a culture of a patient’s own cells,” he noted.
The article "A Self-Reconfiguring Metamorphic Nanoinjector for Injection into Mouse Zygotes" by Quentin T. Aten, Brian D. Jensen, Sandra H. Burnett, and Larry L. Howell will be published in the journal Review of Scientific Instruments on Tuesday, May 13, 2014 (DOI: 10.1063/1.4872077). After that date, it will be available at: http://scitation.aip.org/content/aip/journal/rsi/85/5/10.1063/1.4872077
The paper's first author Quentin Aten participated in this research while at Brigham Young University. He is now working at Nexus Spine LLC.
ABOUT THE JOURNAL
The journal Review of Scientific Instruments, which is produced by AIP Publishing, presents innovation in instrumentation and methods across disciplines. See: http://rsi.aip.org/
Jason Socrates Bardi | newswise
O2 stable hydrogenases for applications
23.07.2018 | Max-Planck-Institut für Chemische Energiekonversion
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
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23.07.2018 | Life Sciences | <urn:uuid:209144f7-5547-4d63-b97f-acdb838db84d> | 3.578125 | 1,433 | Content Listing | Science & Tech. | 41.948646 | 95,514,135 |
In linear algebra, a diagonal matrix is a matrix in which the entries outside the main diagonal are all zero. The term usually refers to square matrices. An example of a 2-by-2 diagonal matrix is ; the following matrix is a 3-by-3 diagonal matrix:. An identity matrix of any size, or any multiple of it, will be a diagonal matrix.
As stated above, the off-diagonal entries are zero. That is, the matrix D = (di,j) with n columns and n rows is diagonal if
However, the main diagonal entries are unrestricted.
Rectangular diagonal matricesEdit
The term diagonal matrix may sometimes refer to a rectangular diagonal matrix, which is an m-by-n matrix with all the entries not of the form di,i being zero. For example:
Symmetric diagonal matricesEdit
The following matrix is a symmetric diagonal matrix:
In the remainder of this article we will consider only square matrices.
A square diagonal matrix with all its main diagonal entries equal is a scalar matrix, that is, a scalar multiple λI of the identity matrix I. Its effect on a vector is scalar multiplication by λ. For example, a 3×3 scalar matrix has the form:
For an abstract vector space V (rather than the concrete vector space ), or more generally a module M over a ring R, with the endomorphism algebra End(M) (algebra of linear operators on M) replacing the algebra of matrices, the analog of scalar matrices are scalar transformations. Formally, scalar multiplication is a linear map, inducing a map (send a scalar λ to the corresponding scalar transformation, multiplication by λ) exhibiting End(M) as a R-algebra. For vector spaces, or more generally free modules , for which the endomorphism algebra is isomorphic to a matrix algebra, the scalar transforms are exactly the center of the endomorphism algebra, and similarly invertible transforms are the center of the general linear group GL(V), where they are denoted by Z(V), follow the usual notation for the center.
The operations of matrix addition and matrix multiplication are especially simple for symmetric diagonal matrices. Write diag(a1, ..., an) for a diagonal matrix whose diagonal entries starting in the upper left corner are a1, ..., an. Then, for addition, we have
- diag(a1, ..., an) + diag(b1, ..., bn) = diag(a1 + b1, ..., an + bn)
and for matrix multiplication,
- diag(a1, ..., an) · diag(b1, ..., bn) = diag(a1b1, ..., anbn).
- diag(a1, ..., an)−1 = diag(a1−1, ..., an−1).
In particular, the diagonal matrices form a subring of the ring of all n-by-n matrices.
Multiplying an n-by-n matrix A from the left with diag(a1, ..., an) amounts to multiplying the ith row of A by ai for all i; multiplying the matrix A from the right with diag(a1, ..., an) amounts to multiplying the ith column of A by ai for all i.
Operator matrix in eigenbasisEdit
As explained in determining coefficients of operator matrix, there is a special basis, e1, ..., en, for which the matrix takes the diagonal form. Hence, in the defining equation , all coefficients with i ≠ j are zero, leaving only one term per sum. The surviving diagonal elements, , are known as eigenvalues and designated with in the equation, which reduces to . The resulting equation is known as eigenvalue equation and used to derive the characteristic polynomial and, further, eigenvalues and eigenvectors.
The determinant of diag(a1, ..., an) is the product a1...an.
The adjugate of a diagonal matrix is again diagonal.
A square matrix is diagonal if and only if it is triangular and normal.
Any square diagonal matrix is also a symmetric matrix.
A symmetric diagonal matrix can be defined as a matrix that is both upper- and lower-triangular. The identity matrix In and any square zero matrix are diagonal. A one-dimensional matrix is always diagonal.
Diagonal matrices occur in many areas of linear algebra. Because of the simple description of the matrix operation and eigenvalues/eigenvectors given above, it is typically desirable to represent a given matrix or linear map by a diagonal matrix.
In fact, a given n-by-n matrix A is similar to a diagonal matrix (meaning that there is a matrix X such that X−1AX is diagonal) if and only if it has n linearly independent eigenvectors. Such matrices are said to be diagonalizable.
Over the field of real or complex numbers, more is true. The spectral theorem says that every normal matrix is unitarily similar to a diagonal matrix (if AA∗ = A∗A then there exists a unitary matrix U such that UAU∗ is diagonal). Furthermore, the singular value decomposition implies that for any matrix A, there exist unitary matrices U and V such that UAV∗ is diagonal with positive entries.
In operator theory, particularly the study of PDEs, operators are particularly easy to understand and PDEs easy to solve if the operator is diagonal with respect to the basis with which one is working; this corresponds to a separable partial differential equation. Therefore, a key technique to understanding operators is a change of coordinates–in the language of operators, an integral transform–which changes the basis to an eigenbasis of eigenfunctions: which makes the equation separable. An important example of this is the Fourier transform, which diagonalizes constant coefficient differentiation operators (or more generally translation invariant operators), such as the Laplacian operator, say, in the heat equation.
Especially easy are multiplication operators, which are defined as multiplication by (the values of) a fixed function–the values of the function at each point correspond to the diagonal entries of a matrix. | <urn:uuid:04c59c85-61be-44f1-9b97-72f997b45cbb> | 3.390625 | 1,336 | Knowledge Article | Science & Tech. | 47.593273 | 95,514,193 |
Spin: The Quantum Property That Should Have Been Impossible
How a quantum number that made no physical sense turned out to be real… and irreplaceable.
In the early 1920s, physicists were first working out the mysteries of the quantum Universe. Particles sometimes behaved as waves, with indeterminate positions, momenta, energies, and other properties. There was an inherent uncertainty to a great many properties that we could measure, and physicists raced to work out the rules.
Amidst this frenzy, a young Dutch researcher named George Uhlenbeck implored Paul Ehrenfest, his research supervisor at the University of Leiden, not to submit the paper he wrote with Samuel “Sam” Goudsmit about a new quantum number called spin. It was not correct, Uhlenbeck told him in a frenzy. Let’s just drop it and start over, he implored.
Uhlenbeck and Goudsmit, both then in their mid-20s, had just showed their joint result to the great Dutch physicist Hendrik Lorentz who had found what seemed like a major error. Electrons, he pointed out, couldn’t possibly rotate fast enough to generate the magnetic moment (interaction strength between a particle and an external magnetic field) that the duo had predicted. The particles would need to whirl faster than the sacred speed limit of light. How could they? The spin paper is unphysical, Uhlenbeck told Ehrenfest, and should not be published.
Ehrenfest’s reply was curt. “It is too late,” he told Uhlenbeck. “I have already submitted the paper. It will be published in two weeks.” Then he added, “Both of you are young and can afford to do something stupid.”
Ehrenfest’s words certainly weren’t comforting. Surely, Uhlenbeck didn’t want to start off his career with a foolish error. Luckily, however, the spin quantum number, interpreted abstractly and having nothing whatsoever to do with rotation despite its name, has become an essential feature of modern physics. Electrons somehow acted in a magnetic field as if they were whirling, even thought they really couldn’t be. Uhlenbeck and Goudsmit’s roulette wheel bet on a weird new concept had paid off handsomely.
One of the harshest critics of spin was the acerbic physicist Wolfgang Pauli. Pauli, like Ehrenfest was born in Vienna, and moved elsewhere for his career. Like Lorentz, Pauli believed at first that spin was unphysical. (In January 1925, German American researcher Ralph Kronig had made a similar suggestion to Pauli, which he had immediately rejected and was never published.) He changed his mind only after Llewellyn Thomas demonstrated a phenomenon called “Thomas precession” that examined spin using special relativity.
Pauli and Ehrenfest shared a blunt demeanor and willingness to criticize others in matters of science. They had first met in 1922 at the “Bohrfestspiele” (celebration of Niels Bohr’s work around the time of his Nobel Prize ) in Göttingen, Germany. Pauli, then in his early 20s, was already famous as a “wunderkind” for an excellent article about general relativity that appeared in a scientific encyclopedia edited by German physicist Arnold Sommerfeld. Ehrenfest and his wife had contributed a piece on statistical mechanics for the same volume. Pauli and Ehrenfest’s initial conversation centered on those respective works.
As physicist Oskar Klein reported: “On that occasion Ehrenfest stood a little away from Pauli, looked at him mockingly and said: ‘Herr Pauli, I like your article better than I like you! To which Pauli very calmly replied: ‘That is funny, with me it is just the opposite!’”
It was ironic that Pauli was initially opposed to spin, given that one of his key proposals — the exclusion principle — was one of the main motivators for its development. Introduced in early 1925, it stated that no two electrons (later extended to an entire class of particles called fermions) could occupy exactly the same quantum state. (Other types of particles, such as photons, that don’t obey that law are called bosons.)
Quantum states in atoms (such as hydrogen) can be characterized by quantum numbers denoting the properties of an electron occupying such a state. The principal quantum number, introduced by Bohr, described the energy of an electron due to its electric interaction with the nucleus. The second and third quantum numbers, introduced by Sommerfeld, pertained to aspects of an electron’s angular momentum (a measure of the shape and configuration of its orbit). Traditionally, each of those quantum numbers were integers — counting numbers denoting a finite set of possibilities, such as the seat and row numbers in an arena. In tandem, those three quantum numbers determine how the probability clouds representing the electrons position themselves in the “stadium” surrounding the nucleus. That intricate pattern, well known by chemists, helps explain the periodic table.
However, as Goudsmit realized in May 1925, there was a problem with using pure integers to characterize the quantum states. If you did, the exclusion principle couldn’t be maintained. Two electrons in the ground state (lowest energy level) of an atom would have identical set of those three quantum numbers. Goudsmit found that by introducing a fourth quantum number, representing a kind of intrinsic or extra angular momentum, that could take on only one of two possible values — either +½ or -½ — he could preserve the Pauli exclusion principle. The ground state could still have two electrons, but their fourth quantum numbers would be opposite: if one was +½, the other would be -½.
Introducing a half-integer quantum number without physical justification was a rather audacious move. In a stadium concert, if an agency issued two tickets for the same seat A11 by labeling them A10½ & A11½ that would seem like chicanery. In hindsight, Goudsmit freely admitted that his physical understanding was not developed enough to justify such a move. He was working part time with Pieter Zeeman on atomic spectral lines, but had yet to see the connection. Zeeman had found extra spectral lines when an atom was placed in a magnetic field for which there was no explanation. Luckily Ehrenfest paired Goudsmit with Uhlenbeck, who knew a greater deal of foundational physics.
As Goudsmit recalled, “Ehrenfest said: ‘You should work together with him for a while, then he may learn something about the new atomic structure and all that spectral business.’ What he clearly thought, of course, was: ‘Perhaps I might learn a little bit of real physics from Uhlenbeck.’”
Uhlenbeck learned from Goudsmit about the anomalous spectral lines as well as his theory of a half-integer quantum number and brilliantly connected the two ideas. The fourth quantum number, Uhlenbeck pointed out, made sense if the electron generated its own magnetic field like a spinning ball of charge. If it was a mini-magnet that could spin either clockwise or counterclockwise, it would have two different energy states in the presence of an external magnet — either aligned or anti-aligned — which would explain the split in spectral lines. Goudsmit was convinced. They wrote up their results and gave them to Ehrenfest, who promptly submitted them to a journal.
The young physicists were lucky that Ehrenfest could be impulsive. If he had discussed the spin idea with others, probably few in the physics community (except, potentially, for Werner Heisenberg, who was also thinking about half-integer quantum numbers) would have supported it. But once it was published, and the spin idea was re-interpreted as an abstract quantum number, it seemed the perfect way of understanding Pauli’s exclusion principle. Integer “stadium seating” for electrons was out, half-integer was in.
When they left Leiden, Uhlenbeck and Goudsmit conducted a different kind of experiment, dubbed the “Michigan experiment,” when they both took on roles as Assistant Professors at the University of Michigan at the same time. They even collaborated on training graduate students, including Dutch physicist Max Dresden (who would become the research supervisor of this author and carry on the pedagogical tradition handed down by Ehrenfest, Uhlenbeck, and Goudsmit.) Open-minded inquiry was the hallmark of that school of thought — which splendidly led to the important concept of spin.
Paul Halpern is the author of fifteen popular science books, including The Quantum Labyrinth: How Richard Feynman and John Wheeler Revolutionized Time and Reality.
Starts With A Bang is now on Forbes, and republished on Medium thanks to our Patreon supporters. Ethan has authored two books, Beyond The Galaxy, and Treknology: The Science of Star Trek from Tricorders to Warp Drive. | <urn:uuid:2249bbfd-8fde-49e8-b6f3-f1ae4d5de42e> | 2.859375 | 1,921 | Nonfiction Writing | Science & Tech. | 39.827519 | 95,514,196 |
Sulfur Periodic Table
Posted on Jul 15, 2018 by Maria Nieto
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These two infrared images of C/2013 (Comet Siding Spring) were taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard NASA's Mars Reconnaissance Orbiter (MRO) on Oct. 19, 2014.
Comet Siding Spring – an Oort Cloud comet that may contain material from the formation of the solar system some 4.6 billion years ago – was making its first voyage through the inner solar system. CRISM and many other instruments and spacecraft combined to provide an unprecedented data set for an Oort Cloud comet.
CRISM acquired the first image at 2:16 pm EDT on Oct. 19, just prior to the comet's closest approach to Mars at 2:27 pm EDT, when it came within roughly 88,000 miles of the planet. The second image was taken 37 minutes later, during which the comet – traveling at approximately 34 miles per second – had traversed one-third of the way across the Martian sky.
The scale of the left image is approximately 4 kilometers per pixel; for the right image, it is about 5 kilometers per pixel. The images, which have had brightness and color enhancements, provide very different perspectives on this intriguing comet.
The images show the inner part of the cloud of dust, called the coma, that is generated around the nucleus by the warmth of the sun. The solid nucleus itself is not resolved. CRISM observed 107 different wavelengths of light in each pixel. Here, only three colors are shown.
Researchers think the appearance of color variations in the inner coma could be due to the properties of the comet's dust, possibly dust grain size or composition. The full spectra will be analyzed to better understand the reason for the color variations.
CRISM is one of six instruments on NASA's Mars Reconnaissance Orbiter. The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland provided and operates CRISM; Lockheed Martin Space Systems in Denver built the orbiter.
NASA's Jet Propulsion Laboratory in Pasadena, California manages MRO for NASA's Science Mission Directorate, Washington, D.C. For more information about NASA Mars missions, visit: www.nasa.gov/mars
The Applied Physics Laboratory, a not-for-profit division of The Johns Hopkins University, meets critical national challenges through the innovative application of science and technology. For more information, visit www.jhuapl.edu
Geoffrey Brown | newswise
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
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- Open Access
Asymmetric dihedral angle offsets for large-size lunar laser ranging retroreflectors
© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB. 2011
- Received: 21 July 2011
- Accepted: 9 November 2011
- Published: 12 December 2011
The distribution of two-dimensional velocity aberration is off-centered by 5 to 6 microradians in lunar laser ranging, due to the stable measurement geometry in the motion of the Earth and the Moon. The optical responses of hollow-type retroreflectors are investigated through numerical simulations, especially focusing on large-size, single-reflector targets that can ultimately minimize the systematic error in future lunar laser ranging. An asymmetric dihedral angle offset, i.e. setting unequal angles between the three back faces, is found to be effective for retroreflectors that are larger than 100 mm in diameter. Our numerical simulation results reveal that the optimized return energy increases approximately 3.5 times more than symmetric dihedral angle cases, and the optimized dihedral angle offsets are 0.65–0.8 arcseconds for one angle, and zeroes for the other two angles.
Laser ranging has been the most precise method to directly measure the Earth-Moon distance since the Apollo-Lunokhod era. Beginning in 1969, the Apollo astronauts placed three panels with 100 or 300 retroreflectors of 38mm diameter, and the Lunokhod rovers left two panels with 14 triangular retroreflectors of 106-mm length of each side. The optical energy of a return signal is very low in lunar laser ranging—typically well below the one photon level, even by using 1- to 1.5-m telescopes located at high altitudes. Therefore, there have been only a handful of laser ranging stations in the world that can receive echoes from these lunar targets. Up to now, the majority of lunar laser ranging data has come from the echoes from the Apollo-15 array that is made up of 300 retroreflectors. The targets of Apollo-11, -14 and Lunokhod-2 have been also tracked. It was recently reported that the long-lost Lunokhod-1 target was successfully tracked by the Apache Point laser ranging station with its 3.5-metre telescope (Murphy et al., 2010b).
Feasibility studies with larger-size reflectors are actively ongoing for future lunar laser ranging targets. For instance, Currie et al. (2011) have designed and tested a 10-cm-diameter uncoated prism retroreflector. Otsubo et al. (2010) have demonstrated a numerical optical simulation which suggested that velocity aberration should be taken into account for a large-size retroreflector. The primary advantage of the concept of the single retroreflector system is to ultimately minimize the so-called target signature effect, which makes measurement less precise due to the multiple reflection points and the resultant pulse spreading. In comparison with the prism retroreflectors that have been placed on the Moon and a number of artificial satellites, hollow-type retroreflectors (also known as open retroreflectors) are generally lighter, and are expected to perform better per mass provided that the two types of retroreflectors behave the same in the Moon environment. This paper focuses on a numerical simulation for hollow-type retroreflectors as we proposed for the SELENE-2 project (Tanaka et al., 2008), but a similar approach is surely possible for prismtype retroreflectors.
It should be mentioned that the actual optical behavior is also affected by manufacturing error and the time-varying environment at the Moon’s surface, which are the on-going issues in and around our group, but such an investigation is out of the scope of this paper.
2. Two-dimensional Velocity Aberration in Lunar Laser Ranging
It should be emphasized that such two-dimensional modeling is not required for Earth-orbiting artificial satellites at low or middle altitudes, because the azimuth angle of incidence toward a retroreflector varies in time and space. In the case of lunar laser ranging, however, the azimuthal distribution of the velocity aberration vector is shifted to one side.
Now let us construct a target-fixed reference frame (X Y Z) T whose axes are aligned to the principal axes of the lunar moment of inertia (Archinal et al., 2011), whereas a precise definition is not critical in this study. The X-axis is taken positive approximately toward the Mean Earth, and the Z-axis is taken positive approximately toward the mean rotation-axis direction of the Moon. The Y-axis is chosen so that the (X Y Z) T coordinates are right-handed.
We see from Fig. 2 that the velocity aberration is not evenly distributed in the Y-Z plane at all, and is off-centered to the area where the Y -component is between +4 to +7 microradians and the Z-component is between −2to +2 microradians. This is interpreted as a result of the fact that the orbital motion of the Moon is dominating in the velocity field, and its direction is always close to the −Y direction. It should also be noted that the velocity of a station on the rotating Earth also has an impact on the velocity aberration, but is always below half of the orbital motion of the Moon.
3. Asymmetric Dihedral Angle Offsets
A dihedral angle offset is defined as a deviation from the right angle of the angles between two neighboring faces. Dihedral angle offsets have been set to 0.5 to 2.0 arcseconds for the retroreflectors on Earth-orbiting artificial satellites to enlarge the far-field diffraction and to compensate for the velocity aberration. The three dihedral angles between the three back faces have typically been set to be symmetric in these cases, as was the case in Otsubo et al. (2010). Symmetrical dihedral angle offsets symmetrically expand the far-field diffraction pattern. In this study, however, the search of the best dihedral angle offsets is extended by making one dihedral angle offset (“δ2” in Fig. 1) free from the other two. We now attempt to evaluate the far-field diffraction pattern with such asymmetric dihedral angle offsets.
Let us focus on hollow-type retroreflectors in this simulation to evaluate the feasibility of large-size retroreflectors in lunar laser ranging. The diameter of a hollow retroreflector is set to be variable from 60–250 mm with circular front faces. The wavelength of the incident laser beam is set to 532 nm, which is common in the current laser ranging network. The software used in this study is an updated version of our previous study (Otsubo et al., 2010), and the mathematical background is well documented in Hecht (2002).
In Fig. 3, the first graph (a) shows the case of no dihedral angles, which makes the optical energy too concentrated at the centre, out of the velocity aberration area. The weighted average of intensity is 34 times that of an Apollo retroreflector. The second graph (b) is the best case in Otsubo et al. (2010), when the dihedral angle offsets are symmetrically set to 0.35 arcseconds. This pattern indeed illuminates the velocity aberration area and the intensity amounts to 169 Apollo retroreflectors, but its energy is two-dimensionally scattered beyond the required area. The last graph (c) shows the most efficient case of a large number of numerical tests: the dihedral angle offsets are asymmetric, (δ1,δ2, δ3) = (0.00, 0.65, 0.00) arcseconds. The weighted average intensity corresponds to 599 Apollo retroreflectors, about 3.5 times that of the case (b). The far-field diffraction pattern in graph (c) has only two illuminating areas, one of which efficiently shows the velocity aberration region given in Fig. 2.
We always obtain optimum results at τ1 = τ3 = 0. When these two angles deviate from zero, the diffraction pattern symmetrically expands toward the −Z and +Z directions. The intensity in the velocity aberration region becomes attenuated, and, therefore, dihedral angle offsets for τ1 = τ3 are not preferred.
Optimized performance of hollow retroreflector and dihedral angle offsets.
Aperture diameter (mm)
Optimum dihedral angle offset (arcseconds)
Optimum intensity (× Apollo retroreflector)
(0.00, 0.00, 0.00)
(0.00, 0.25, 0.00)
(0.00, 0.80, 0.00)
(0.00, 0.80, 0.00)
(0.00, 0.75, 0.00)
(0.00, 0.70, 0.00)
(0.00, 0.65, 0.00)
(0.00, 0.65, 0.00)
(0.00, 0.65, 0.00)
When the reflector size is small, no dihedral angle offsets are required. This is because the diffraction spread is large enough to cover the velocity aberration within the first minimum ring. The transition occurs around 80–100-mm size, where there is almost no difference between zero dihedral angle offset and the optimum dihedral angle offset for a large-size retroreflector mentioned below. In the case of a larger reflector size, the dihedral angle offsets becomes advantageous and the optimum combination stays around (0.00, 0.65–0.80, 0.00) arcseconds.
An empirical study had revealed that the intensity is proportional to the 2.2–2.6th power of diameter in the case of spherical geodetic satellites (Otsubo and Appleby, 2003). However, the optimum intensity in Table 1 suggests that it is proportional to about the 3.5th power of diameter in this study. Since the weight is roughly proportional to the cube of the diameter, this result suggests a groundbreaking theory: the larger a retroreflector is, the stronger is the intensity per unit mass which may be expected.
The condition τ1 = τ3 has been assumed so far, and this is, in fact, harmonic to the orientation of a retroreflector defined in Fig. 1. When this equality is lost, the difference between τ1 and τ3 contributes to the rotation of the diffraction pattern, which makes the situation simply worse on average in this orientation condition. When the azimuthal orientation of a retroreflector was rotated from Fig. 1, such a rotation would be required. Therefore, the condition τ1 = τ3 does not lose generality in the configuration of this study.
Unlike most of Earth-orbiting artificial satellites, the two-dimensional velocity aberration vector in lunar laser ranging is simply off-centered toward the +Y direction by 4–7 microradians, due to the stable measurement geometry. A retroreflector with optimum asymmetric dihedral angle offsets are found to efficiently illuminate this region, about 3.5 times stronger on average than one with optimum symmetric dihedral angle offsets. Such an asymmetric combination is required for a hollow-type retroreflector larger than 100-mm diameter, and the optimum combination is found around (τ1, τ2, τ3) = (0.00, 0.65–0.80, 0.00) arcseconds.
The authors would like to thank the reviewers for their comments which helped to improve the manuscript. This study is supported by a Grant-in-Aid for Young Scientists (B) 70358943 of KAKENHI.
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Using a neutrino detector made of Antarctic ice, astronomers have for the first time pinpointed the source of a handful of high-energy neutrinos from far beyond our galaxy: a powerful blazar shining like a beacon from nearly 4 billion light-years away.
The extragalactic neutrinos and their origins, described in two papers in the journal Science, shed light on the century-old question of where cosmic rays come from and offer the first clear proof of the potential for this nascent brand of astronomy.
"We are not going to solve high-energy astrophysics in the old-fashioned way anymore," said Francis Halzen, a particle astrophysicist at the University of Wisconsin-Madison and principal investigator for IceCube, the frozen observatory that made the discovery.
Neutrinos are exceedingly tiny particles, weighing at less than one ten-billionth the mass of a proton. Many billions of these subatomic particles pass through your fingertip every second. Even though they're plentiful, neutrinos don't interact much with matter, passing through planets, stars, even entire galaxies like speeding subatomic phantoms.
But astronomers hunt for neutrinos anyway, partly because they've suspected that they could solve the mystery of the origins of the cosmic rays that bombard Earth from space.
Cosmic rays are highly energetic charged particles, mostly protons, that have been revved up to enormous energies and hurled across the universe. It would take a powerful cosmic engine -- say, a supermassive black hole at a galaxy's heart, or an enormous supernova -- to accelerate these atomic fragments to such high energies.
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But until now, scientists haven't known for sure where these cosmic rays come from. That's because as they travel intergalactic distances, their paths are warped by the magnetic fields that permeate space -- which means that by the time they get to Earth, they're no longer pointing back at their source.
Neutrinos offer a solution to this problem because these neutral particles are unaffected by magnetic fields. By the time they reach Earth, they're still pointing the way home. On top of that, the kinds of powerful cosmic forges that would generate high-energy cosmic rays also would produce a torrent of high-energy neutrinos.
But the very quality that makes these ghostly particles so useful -- the fact that they don't interact with matter -- also makes neutrinos exceedingly difficult for scientists to catch in action. For every individual high-energy neutrino hit, Halzen said, roughly 10,000 or 100,000 more pass through unscathed.
The IceCube collaboration set out to detect that rare, singular neutrino strike. Composed of more than 5,000 sensors embedded in a cubic kilometer of ice sitting deep beneath the Antarctic surface, IceCube picks up the flashes of blue light caused by secondary particles after a neutrino makes contact. The scientists can analyze that resulting light track to tell what direction the particle came from and how energetic it was when it hit. | <urn:uuid:e0abc4ba-e63a-4d74-9eb1-f7c8a6030dd4> | 3.484375 | 630 | News Article | Science & Tech. | 30.346291 | 95,514,234 |
PeeriMagic-angle-spinning NMR used to probe protein/microtubule assembly at atomic scale
A latticework of tiny tubes called microtubules gives your cells their shape and also acts like a railroad track that essential proteins travel on. But if there is a glitch in the connection between train and track, diseases can occur.
In the Proceedings of the National Academy of Sciences, Tatyana Polenova, professor of chemistry and biochemistry, and her team at the University of Delaware, together with John C. Williams, associate professor at the Beckman Research Institute of City of Hope in Duarte, California, reveal for the first time -- atom by atom -- the structure of one of these proteins bound to a microtubule.
The protein of focus, CAP-Gly, short for "cytoskeleton-associated protein-glycine-rich domains," is a component of dynactin, which binds with the motor protein dynein to move cargoes of essential proteins along the microtubule tracks. Mutations in CAP-Gly have been linked to such neurological diseases and disorders as Perry syndrome and distal spinal bulbar muscular dystrophy.
The research team used magic-angle-spinning nuclear magnetic resonance spectrometry (NMR) in the Department of Chemistry and Biochemistry at UD to unveil the structure of the CAP-Gly protein assembled on polymerized microtubules. The CAP-Gly protein has 1,329 atoms, and each tubulin dimer, which is a building block for microtubules, has nearly 14,000 atoms.
"This is the first time anyone has been able to get an atomic-resolution structure of any microtubule-associated protein assembled on polymerized microtubules," Polenova says. "With magic-angle-spinning NMR, we can look into the structure of this and other assemblies of microtubules and their associated proteins and gain critical insights into their function and dynamics, as well as begin to gather clues as to how mutations cause disease."
In this technique, a sample is placed in the NMR's small, tube-like rotor, which is then spun inside the NMR magnet at an angle of 54.74 degrees -- called the "magic angle" because it suppresses the atoms from interacting magnetically.
The result is a high-resolution protein fingerprint, a graph of hundreds of peaks representing the frequencies of two or more interacting atoms. These data are then used to calculate the 3-D structures.
The 3-D structures of CAP-Gly, which show the spatial arrangement of atoms in the protein molecule, are different between the free state of the protein and its bound state to the microtubule. These structures reveal how the protein interacts with microtubules, predominantly through its loop regions, which adopt specific conformations upon binding.
However, static structures of CAP-Gly do not tell the whole story about the protein.
"Just as we are always moving our arms and legs about, proteins are very dynamic. They do not stand still," Polenova says. "These motions are essential to their biological function, and NMR spectroscopy is the only technique that can record such movements, with atomic resolution, on a variety of time scales, from picoseconds to arbitrarily long time scales -- seconds, days, weeks -- to help us understand the protein's function. We know from our prior studies that CAP-Gly is dynamic on timescales from nano- to milliseconds, and this mobility is essential for the protein's ability to interact with microtubules and with multiple other binding partners."
The research, which has been ongoing since 2008 when the first data sets were collected, required the development of new protocols for preparing the samples, new NMR experiments to gather various information on structure and dynamics, and new protocols for data analysis.
In the future, Polenova and her team envision using NMR in combination with cryo-electron microscopy, in which samples are studied at extremely low temperatures, typically below 200 degrees Fahrenheit, to look at even more complex systems in a highly preserved form.
Polenova's research team at UD included Si Yan, who received her doctorate from the University in 2014, current doctoral student Changmiao Guo, NMR spectroscopist Guangjin Hou and postdoctoral researchers Huilan Zhang and Xingyu Lu. Williams, at Beckman Research Institute, also was a co-author of the study.
The research was supported by the National Institutes of Health through a grant from the National Institute of General Medical Sciences. The National Science Foundation funded one of the NMR spectrometers used in the research.
Peter Bothum | EurekAlert!
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The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
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Despite the considerable evidence showing that dispersal between habitat patches is often asymmetric, most of the metapopulation models assume symmetric dispersal. In this paper, we develop a Monte Carlo simulation model to quantify the effect of asymmetric dispersal on metapopulation persistence. Our results suggest that metapopulation extinctions are more likely when dispersal is asymmetric. Metapopulation viability in systems with symmetric dispersal mirrors results from a mean field approximation, where the system persists if the expected per patch colonization probability exceeds the expected per patch local extinction rate. For asymmetric cases, the mean field approximation underestimates the number of patches necessary for maintaining population persistence. If we use a model assuming symmetric dispersal when dispersal is actually asymmetric, the estimation of metapopulation persistence is wrong in more than 50% of the cases. Metapopulation viability depends on patch connectivity in symmetric systems, whereas in the asymmetric case the number of patches is more important. These results have important implications for managing spatially structured populations, when asymmetric dispersal may occur. Future metapopulation models should account for asymmetric dispersal, while empirical work is needed to quantify the patterns and the consequences of asymmetric dispersal in natural metapopulations.
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Cells invading into the tissue-like collagen-I matrix under the defective basement membrane.
Amit Pathak and his team have found that one small defect in tissue boundaries known as the basement membrane can lead normal cells to take on characteristics of diseased cells, such as cancer cells, and invade the surrounding tissue.
Homeowners know that one little termite can lead to big problems: While termites are efficient at gnawing away at wood, they can do even more damage if the wood is already broken or has another defect.
Mechanical engineers at Washington University in St. Louis have found the same effect in some of the body's tissue: One small defect in tissue boundaries known as the basement membrane can lead normal cells to take on characteristics of diseased cells, such as cancer cells, and invade the surrounding tissue.
In research published online May 16 in Integrative Biology, Amit Pathak, assistant professor of mechanical engineering in the School of Engineering & Applied Science, and his team found this feedback loop with epithelial cells. These simple cell colonies act as the body's defense against the outside world and also line the inside of the throat, intestines, blood vessels and organs, meaning the epithelial cells could provide a little link to a much bigger issue. Knowledge of this relationship could help researchers find new therapies to halt cancer metastasis.
Researchers already knew that in cancer, epithelial cells transition into mesenchymal types that can degrade the basement membrane, a process stimulated by enzymes called matrix metalloproteinases (MMPs). This process causes further defects in healthy tissue and allows cancer to metastasize. Pathak's team is the first to discover that the reverse also is true — preexisting defects in the basement membrane, such as a wound or small incision, are enough to encourage the normal cells to take on disease characteristics, leading to further degradation of the basement membrane.
Pathak and his team fabricated a basement membrane model using a hydrogel coated with collagen IV, a protein that is the main and most important structural component of the basement membrane. They added normal epithelial cells, which like to stick together, then made a small cut in the gel. After six days, the cells started to break apart, move around and invade the gel, mimicking a tumor invading healthy tissue.
"Because of the defect, the cells started to show signatures of diseased cells," Pathak said. "If there was no defect, they would have stayed the same. This small defect of less than one-tenth of a millimeter caused this whole process of these cells changing."
To show that the cells would have remained the same without the defect, Pathak and his team treated them with an inhibitor of MMPs, which are known to degrade the basement membrane in wound healing. The cells did not change and did not invade the basement membrane.
Previously, researchers believed that once tumor cells became malignant, they would degrade the basement membrane.
"This finding shows that we shouldn't take basement membrane degradation as an inevitable outcome," Pathak said. "In addition to targeting tumor cells, we can determine therapeutic strategies that make the basement membrane more stable. If it is more stable, then we can at least slow down and possibly reverse metastasis."
In addition to the hydrogel model, Pathak and his team made a computational model integrating the biochemical and biophysical effects of the defects on the cellular transitions, which allowed them to make predictions on which they will base future experiments.
The School of Engineering & Applied Science at Washington University in St. Louis focuses intellectual efforts through a new convergence paradigm and builds on strengths, particularly as applied to medicine and health, energy and environment, entrepreneurship and security. With 94 tenured/tenure-track and 28 additional full-time faculty, 1,300 undergraduate students, 1,200 graduate students and 20,000 alumni, we are working to leverage our partnerships with academic and industry partners — across disciplines and across the world — to contribute to solving the greatest global challenges of the 21st century.
Walter C, Davis J, Mather J, Pathak A. "Physical defects in basement membrane-like collagen-IV matrices trigger mesenchymal transition and invasion in normal epithelial cells." Integrative Biology. Online May 16, 2018. http://dx.doi.org/10.1039/C8IB00034D
Funding for this research was provided by the National Science Foundation and the Edward Mallinckrodt, Jr. Foundation. | <urn:uuid:f7455c90-712f-4a38-a5eb-b8ddbdd662f8> | 3.5625 | 926 | News (Org.) | Science & Tech. | 34.836806 | 95,514,251 |
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Researchers at the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) established a new world efficiency record for quantum dot solar cells, at 13.4%.
Colloidal quantum dots are electronic materials and because of their astonishingly small size (typically 3-20 nanometers in dimension) they possess fascinating optical properties. Quantum dot solar cells emerged in 2010 as the newest technology on an NREL chart that tracks research efforts to convert sunlight to electricity with increasing efficiency. The initial lead sulfide quantum dot solar cells had an efficiency of 2.9%. Since then, improvements have pushed that number into double digits for lead sulfide reaching a record of 12% set last year by the University of Toronto. The improvement from the initial efficiency to the previous record came from better understanding of the connectivity between individual quantum dots, better overall device structures and reducing defects in quantum dots.
NREL scientists Joey Luther and Erin Sanehira are part of a team that has helped NREL set an efficiency record of 13.4% for a quantum dot solar cell.
The latest development in quantum dot solar cells comes from a completely different quantum dot material. The new quantum dot leader is cesium lead triiodide (CsPbI3), and is within the recently emerging family of halide perovskite materials. In quantum dot form, CsPbI3 produces an exceptionally large voltage (about 1.2 volts) at open circuit.
“This voltage, coupled with the material’s bandgap, makes them an ideal candidate for the top layer in a multijunction solar cell,” said Joseph Luther, a senior scientist and project leader in the Chemical Materials and Nanoscience team at NREL. The top cell must be highly efficient but transparent at longer wavelengths to allow that portion of sunlight to reach lower layers. Tandem cells can deliver a higher efficiency than conventional silicon solar panels that dominate today’s solar market.
This latest advance, titled “Enhanced mobility CsPbI3 quantum dot arrays for record-efficiency, high-voltage photovoltaic cells,” is published in Science Advances. The paper was co-authored by Erin Sanehira, Ashley Marshall, Jeffrey Christians, Steven Harvey, Peter Ciesielski, Lance Wheeler, Philip Schulz, and Matthew Beard, all from NREL; and Lih Lin from the University of Washington.
The multijunction approach is often used for space applications where high efficiency is more critical than the cost to make a solar module. The quantum dot perovskite materials developed by Luther and the NREL/University of Washington team could be paired with cheap thin-film perovskite materials to achieve similar high efficiency as demonstrated for space solar cells, but built at even lower costs than silicon technology--making them an ideal technology for both terrestrial and space applications.
“Often, the materials used in space and rooftop applications are totally different. It is exciting to see possible configurations that could be used for both situations,” said Erin Sanehira a doctoral student at the University of Washington who conducted research at NREL.
The NREL research was funded by DOE’s Office of Science, while Sanehira and Lin acknowledge a NASA space technology fellowship.
NREL is the U.S. Department of Energy's primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC. | <urn:uuid:062354fc-9905-498c-bca9-4678826c6e69> | 3.4375 | 732 | News Article | Science & Tech. | 31.23427 | 95,514,259 |
The revolution of nanomaterials: superabsorbers that trap sunlight
- News 05 February 2018 772 hits
ICMAB researchers have designed ultrathin materials that maximize the absorption of light in a large range of the solar spectrum. The followed strategy, low cost and fully scalable, is based on combining the thin layer deposition of semiconductors on metals, and the nanostructuring of the material forming photonic crystals. The obtained superabsorbers materials have many potential applications, especially in the field of photovoltaic energy and photodetection.
One of the challenges in the field of photovoltaic energy is to maximize the sunlight absorbed using the minimum quantity of material, in order to maximize its efficiency.
Researchers from ICMAB, led by Dr. Agustín Mihi, have created materials that largely absorb a wide range of the solar spectrum, between 400 and 1500 nm, using an ultrathin layer of less than 100 nm thick of material.
The followed strategy combines thin layers of semiconductors on a metal support (in this case, germanium on gold), to maximize the absorption in the visible range (400-700 nm), and the nanostructuring through nanolithography of the germanium layer in a square matrix, so that it acquires plasmonic and photonic properties, and maximizes the absorption in the near-infrared area (700-1500 nm).
The procedure to synthesize this photonic structure is completely scalable, which adds interest to the aforementioned advantageous optical properties. Moreover, the researchers provide, in the study published in Advanced Materials, the design guidelines to synthesize other types of materials following the same strategy.
The resulting superabsorber material has a great potential in applications in which a large quantity of light is wanted to convert into electrons, such as photodetection, photocatalysis, and in the field of photovoltaic energy to obtain electrical energy. We are heading for a future with thinner and more efficient solar panels!
Figure: a) Coloured Scanning Electron Microscopy (SEM) image of the germanium photonic structure fabricated over a gold layer; b) (left axis) Solar spectral irradiance that reaches the sea level (yellow) with the fraction absorbed by our architecture (Orange) and the total absorption of our superabsorber (right axis).
Reference article: Ultrathin Semiconductor Superabsorbers from the Visible to the Near-Infrared. Pau Molet, Juan Luis Garcia-Pomar, Cristiano Matricardi, Miquel Garriga, Maria Isabel Alonso and Agustín Mihi. Advanced Materials, 12 January 2018. DOI: 10.1002/adma.201705876.
UPDATE: This news appeared in La Vanguardia: read it here.
Related Topics: Websites | <urn:uuid:d0e8eda8-29d4-4cd7-83e9-8f615635afff> | 2.96875 | 591 | News (Org.) | Science & Tech. | 20.073579 | 95,514,260 |
Moss brought back to life after 1,500 years frozen in ice
Researchers from the British Antarctic Survey and Reading University have demonstrated that, after over 1,500 years frozen in Antarctic ice, moss can come back to life and continue to grow.
For the first time, this vital part of the ecosystem in both polar regions has been shown to have the ability to survive century to millennial scale ice ages. This provides exciting new insight into the survival of life on Earth.
The team, reporting in Current Biology this week, observed moss regeneration after at least 1,530 years frozen in permafrost. This is the first study to show such long-term survival in any plant; similar timescales have only been seen before in bacteria.
Mosses are known to survive environmental extremes in the short-term with previous evidence confirming up to a 20 year timescale for survival. Their potential to survive much longer timescales had not previously been examined.
Mosses are an important part of the biology of both polar regions. They are the dominant plants over large areas and are a major storer of fixed carbon, especially in the north.
Co-author Professor Peter Convey from the British Antarctic Survey explains:
"What mosses do in the ecosystem is far more important than we would generally realise when we look at a moss on a wall here for instance. Understanding what controls their growth and distribution, particularly in a fast-changing part of the world such as the Antarctic Peninsula region, is therefore of much wider significance."
The team took cores of moss from deep in a frozen moss bank in the Antarctic. This moss would already have been at least decades old when it was first frozen. They sliced the frozen moss cores very carefully, keeping them free from contamination, and placed them in an incubator at a normal growth temperature and light level.
After only a few weeks, the moss began to grow. Using carbon dating, the team identified the moss to be at least 1,530 years of age, and possibly even older, at the depth where the new growth was seen.
According to Professor Convey:
"This experiment shows that multi-cellular organisms, plants in this case, can survive over far longer timescales than previously thought. These mosses, a key part of the ecosystem, could survive century to millennial periods of ice advance, such as the Little Ice Age in Europe.
"If they can survive in this way, then recolonisation following an ice age, once the ice retreats, would be a lot easier than migrating trans-oceanic distances from warmer regions. It also maintains diversity in an area that would otherwise be wiped clean of life by the ice advance.
"Although it would be a big jump from the current finding, this does raise the possibility of complex life forms surviving even longer periods once encased in permafrost or ice."
Issued by the British Antarctic Survey Press Office.
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Tel: +44 (0) 118 378 7115
Notes for editors
The paper: Millennial timescale regeneration in a moss from Antarctica by Esme Roads, Royce E. Longton and Peter Convey is published in Current Biology on Monday 17 March 2014. View the paper at
Images are available on request.
Permafrost: Rock or soil that remains frozen throughout the year.
British Antarctic Survey (BAS), an institute of the Natural Environment Research Council (NERC), delivers and enables world-leading interdisciplinary research in the Polar Regions. Its skilled science and support staff based in Cambridge, Antarctica and the Arctic, work together to deliver research that uses the Polar Regions to advance our understanding of Earth as a sustainable planet. Through its extensive logistic capability and know-how BAS facilitates access for the British and international science community to the UK polar research operation. Numerous national and international collaborations, combined with an excellent infrastructure help sustain a world leading position for the UK in Antarctic affairs. For more information visit http://www.antarctica.ac.uk.
Paul Seagrove | EurekAlert!
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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18.07.2018 | Health and Medicine | <urn:uuid:917cf081-c948-4f87-94ab-4f927e9a30c9> | 3.75 | 1,508 | Content Listing | Science & Tech. | 42.977564 | 95,514,281 |
Underground Life Powered by ElectronsJuly 04, 2016 / Written by: Miki Huynh
Scanning electron microscopy showing attachment of Delftia sp. WE1-13 on carbon cloth fibers, and in vivo fluorescent image of Delftia sp. WE1-13 cells attached to an electrode during electrochemical analysis. Image source: Y. Jangir and M.Y. El-Naggar (USC).
Scientists from the University of Southern California Life Underground team are taking a close look at microorganisms that have developed unique strategies for surviving below the Earth’s surface in oxygen-poor but mineral-rich environments.
In the research paper “Isolation and characterization of electrochemically active subsurface Delftia and Azonexus species,” published in Frontiers of Microbiology, the scientists analyze microbes within a fractured-rock aquifer in Death Valley, CA, using electrodes to draw out and isolate types that gain energy through a process called extracellular electron transfer (EET).
The study is part of growing research on microorganisms able to “live off of electricity.” A recent article from Quanta Magazine followed USC biophysicist Moh El-Naggar and graduate student Yamini Jangir as they examine microbes found in an old gold mine in the Black Hills of South Dakota. The story looks at the history of electron-eating microbial research and suggests how an increased understanding could tell us about life that may grow on other mineral surfaces on Earth, Mars, and beyond.
The research was supported by the NASA Astrobiology Institute.
- Life Underground - Available to Play
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- Yosemite Granite Tells New Story About Earth's Geologic History
- Supporting SHERLOC in the Detection of Kerogen as a Biosignature
- New Estimates of Earth's Ancient Climate and Ocean pH
- How Microbes From Spacecrafts Survive Clean Rooms
- Radical Factors in the Evolution of Animal Life
- Understanding Oxygen as an Exoplanet Biosignature
- Recap of the 2018 Astrobiology Graduate Conference (AbGradCon)
- Astrobiologist Rebecca Rapf Receives Inaugural Maggie C. Turnbull Early Career Award | <urn:uuid:f14ab37a-41e7-40e6-a432-724c1b56ba99> | 3.171875 | 470 | News (Org.) | Science & Tech. | 16.253762 | 95,514,290 |
An international team of researchers presents fresh evidence that confirms the existence of the superheavy chemical element 115. The experiment was conducted at the GSI Helmholtz Center for Heavy Ion Research, an accelerator laboratory located in Darmstadt.
photo: G. Otto, GSI Helmholtz Center for Heavy Ion Research
GSI linear accelerator
Under the lead of physicists from Lund University in Sweden, the group, which included researchers from Johannes Gutenberg University Mainz (JGU) and the Helmholtz Institute Mainz (HIM), was able to present a way to directly identify new superheavy elements. Elements beyond atomic number 104 are referred to as superheavy elements. They are produced at accelerator laboratories and generally decay after a short time. Initial reports about the discovery of an element with atomic number 115 were released from a research center in Russia in 2004. The then presented indirect evidence for the new element, however, was insufficient for an official discovery.
For the new experiment, scientists at the Institute of Nuclear Chemistry at Mainz University took a sample of the exotic element americium. They deposited an americium layer on a thin foil, which was subsequently bombarded with calcium ions at the GSI facility. For the first time, the exploitation of a new detector system allowed registering photons along with the alpha-decay of the new element and its daughter products. Measured photon energies correspond to those expected for X-rays from these products and thus serve as the element's fingerprint.
"This can be regarded as one of the most important experiments in the field in recent years, because at last it is clear that even the heaviest elements' fingerprints can be taken", agreed Professor Dirk Rudolph from Lund University in Sweden and Professor Christoph Düllmann, professor at Mainz University and leading scientist at GSI Darmstadt and HIM. "The result gives high confidence to previous reports. It also lays the basis for future measurements of this kind."
The element 115 is yet to be named: a committee comprising members of the international unions of pure and applied physics and chemistry will review the new findings and decide whether further experiments are needed to acknowledge the discovery of the element. Only after such final acceptance, a name may be proposed by the discoverers.
Besides the X-ray events, the researchers have also obtained data giving them a deeper insight into the structure and properties of the heaviest currently known atomic nuclei. This paves the way towards improved predictions for properties of nuclei beyond the border of current knowledge.
The new findings will soon be presented in the scientific journal The Physical Review Letters.
Dr. Christoph Düllmann | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
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Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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19.07.2018 | Life Sciences | <urn:uuid:ae5ea6bb-a298-47a5-ae50-8e07e5961eb1> | 2.890625 | 1,174 | Content Listing | Science & Tech. | 37.317213 | 95,514,292 |
It’s February, and the night is soft. A high stratus blanket filters the moonlight and moistens your eyelashes. Wet season has been under way for three months now, and soils are saturated. Shallow water stands in boggy slumps, roadside ditches, and semi-permanent mud puddles. Such are locales for a great late-winter expression of amphibian fecundity: the annual gathering of countless Pacific chorus frogs to breed.
A small but iconic member of our bioregion, the tiny frog is widely recognized and loved for its “rib-it” call. While its name may have changed (from Hyla regilla to Pseudacris regilla and from Pacific tree frog, which many people still say, to Pacific chorus frog), the species’ presence in our winter soundscape holds a timeless resonance for humans.
When hundreds or thousands of males occupy a pond, to compete for the company of somewhat fewer females, and night temperatures dip no lower than 51 degrees Fahrenheit, a burst of new rainfall will set off a pulse of tree frog calling and breeding. If you are listening (often haplessly if you live nearby), you are apt to hear a sudden drop to utter silence. Something has alarmed the singers. Then, soon enough, a single frog voice chimes, then several more, then quickly dozens to many hundreds or several thousand—and all at once the collective din swells to vibrate your diaphragm and rib cage as well as your ear bones.
For a creature that weighs only about two grams, this little amphibian—collectively—has plenty of heft. The males emit their two-note “advertisement” calls to try and attract the silent females. Essentially they are using sound to establish how much space each male can claim around a pond. A flashlight might reveal a dense lineup of bright pearlescent globes along the water’s margin—the inflated throats of male tree frogs holding air for the next chorus.
Each female lurking in or near the water makes her choice of a calling male and approaches him to mate. But the close-packed males may continue competing, using a second kind of call to repel their rivals. Their “encounter” call is a shrill trill—and while males use it to establish territory amid the crowd, it actually repels females! Adding to the chaos, physical conflict can occur between males, with individuals grappling for space and dominance.
Ultimately, the purpose for all this activity rules the night. Once a female approaches a male, he abandons his song territory and wraps her from behind, in a position called amplexus; then the female propels them both into quiet, shallow water, where she deposits batches of eggs on aquatic vegetation or other substrates. The male emits sperm to fertilize the multiple clusters of eggs—hundreds of prospective new chorus frogs. Then the female leaves the party (the pond), and the male resumes advertising for another chance to mate.
This seasonal crowd-sourcing of next-generation froglets occurs after each burst of saturating rain that’s followed by warm night temperatures. There can be two such pulses (each several nights long) of chorusing and breeding in February, another two in March, and possibly one in April.
Pacific chorus frog abundance is due to the species’ successful breeding strategy and ability to survive in developed areas with water, its resilience in the face of fungal disease afflicting other amphibians, and the survival of wetland habitat despite massive land-use change. The frogs are found from British Columbia to Baja California, from the coast eastward to Montana and Arizona, and from sea level to 10,000 feet in the Sierra—where there is gradation among forms currently recognized as separate species.
Where do the chorus frog crowds go when ponds begin drying up? Outward to a distance of several hundred yards—or up to a half-mile away! Supposing that each tiny individual travels just a few inches in a single bound, how many reps must he/she perform to travel 1,000 yards?
As dry season advances, skin-moist creatures such as salamanders and frogs must surround themselves with dampness. Like other amphibians adapted to our Mediterranean climate, chorus frogs seek out wet niches in the landscape. Many make use of rodent burrows, where soil moisture persists and invertebrates—their food—abound.
And true to the species’ long-standing common-name identity, these tiny frogs do occasionally climb high in the coastal conifer forest. Web cameras placed in bald eagle nests atop trees so tall they scrape the fog for moisture have documented chorus frogs hopping about capturing insects.
Individual frogs may continue to sing occasionally throughout the year, with a lone voice emanating from the woodshed or a folded deck chair, a sweet reminder of the frog frenzy that marks a mild California winter.
Claire Peaslee is a naturalist, writer, editor, graphic designer, and improvisational theater artist whose home is Point Reyes.
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Gas mixing ratios of SO2, NO2 and HNO3 and nitrate and sulfate concentrations in rainwater have been measured at six sites in Indonesia. The sites, Jakarta, Serang, Cilegon, Merak and Bogor, in Java, and Bukit Koto Tabang in Sumatra, provide a range of pollution regimes in Indonesia. Jakarta and Bogor are heavily polluted sites in Java, whereas Bukit Koto Tabang is a clean air station in a relatively unpopulated area on the west coast of equatorial Sumatra. At these sites rainwater was collected daily and gas samples weekly during 1996. The other three sites Serang, Cilegon and Merak represent smaller regional towns in west Java. At these sites rainwater samples were collected weekly from June 1991 until June 1992. The results show that Jakarta has the highest volume-weighted mean sulfate concentrations in rainwater while the lowest were measured at Bukit Koto Tabang. Volume-weighted mean nitrate concentration was about 24 mu eq L-1 at Jakarta and Bogor, significantly higher than the 0.8 mu eq L-1 measured at Bukit Koto Tabang. Sulfur dioxide mixing ratios ranged from 4-7 ppbv in Jakarta to an average of 1.3 ppbv at Bukit Koto Tabang. Nitrogen dioxide mixing ratio was highest in Jakarta averaging 28 ppbv compared with the background mixing ratio of 1.2 ppbv at Bukit Koto Tabang. Using dry deposition velocities estimated during a separate study in the similar conditions of Malaysia enabled dry deposition estimates of SO2, HNO3 and NO2. Results of estimated total acidic S and N deposition (wet and dry) were greater than 250 meq m(-2) yr(-1) at the Jakarta and Bogor sites compared with about 23 meq m(-2) yr(-1) at Bukit Koto Tabang. At Jakarta and Bogor dry deposition accounted for more than 50% of the total deposition estimates compared with about 20% at Bukit Koto Tabang. Such deposition rates are high when compared to critical loads estimated for Indonesia by the RAINS-Asia model. In this model, critical loads in western Java and equatorial western Sumatra fall into one of two classes: 50-100 and 20-50 meq m(-2) yr(-1). Thus acidic deposition flux at Jakarta and Bogor was found to be above the predicted critical loads even for the more acid insensitive soils.
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London: With increasing human population and rise in agricultural land use in India’s Western Ghats, a number of bat species are findings it difficult to adjust with the changed landscape brought about by deforestation, says a new study.
The researchers found that while bats do not favour tea plantations, some species can survive in coffee plantations.
To assess the impact of rainforest fragmentation and plantations on bats, a team of researchers from National Centre for Biological Sciences, Bangalore, Nature Conservation Foundation, Mysore, and University of Leeds in Britain surveyed bats in the souther Western Ghats.
The researchers found that several species are having difficulty in the transformed landscape – but also found hopeful signs that remaining forest fragments and wildlife-friendly agriculture could offer a lifeline.
“The Western Ghats region is the eighth most biodiverse place in the world but has the highest human population of any of the biodiversity hotspots,” said professor John Altringham from University of Leeds in Britain.
“Historical land use change and development has left only six percent of the original habitat in the region. By looking at bats — which are excellent bioindicators — we are able to learn not only what these changes in the environment mean for bats, but also for wildlife in general,” Altringham pointed out.
The researchers used geographic information system (GIS) computer modelling to look at the relationships between the presence of 10 different bat species and the features of the habitats in which they were found.
The bats were located by a combination of capture and recording of echolocation calls.
The researchers used the information gathered over three years to build ‘habitat suitability models’, to predict what areas would be good habitat for each species across the entire study area.
“Most species preferred forest fragments and the rivers associated with them. No species favoured tea plantations, though a number could make use of them,” lead researcher Claire Wordley from University of Leeds pointed out.
“Two of the bat species we studied, the lesser woolly horseshoe bat and the lesser false vampire bat, were never seen in tea plantations,” Wordley noted.
“Further deforestation would be a serious threat to these species, but the good news is that they are, for the moment, surviving in small forest patches, riverine habitats and in coffee plantations,” Wordley said.
The study was published in the journal Biological Conservation. | <urn:uuid:eb268365-c3ca-4d52-83f2-e4bb3a561be7> | 3.34375 | 505 | News Article | Science & Tech. | 26.864259 | 95,514,316 |
Gastropoda | Archaeogastropoda
Environment / Climate / Range
Northeast Pacific: British Columbia, Canada to Mexico.
Length at first maturity / Size / Weight / Age
Maturity: Lm ? range ? - ? cm Max length : 3.0 cm SHD male/unsexed; (Ref. 95344); common length : 2.5 cm TL male/unsexed; (Ref. 312); max. reported age: 28 years (Ref. 2823)
Shell is thick and dark purple to black; foot is black on the sides (Ref. 312).
It has a shell length of 2.5 cm. Fisheries: Over-harvesting for food in the early 1900s, mainly by Southern European immigrants, caused a drastic drop in population numbers. Today they are still harvested by both Americans of Southern European and Asian ancestries; heavy regulation by the Department of Fish and Game has allowed populations to recover (Ref. 312). Habitat: Occurs in high to middle intertidal zones on rocky surfaces or in pools not covered in algae. Diet: eats many species of algae including micro and macroscopic. Life span: up to 25 years (Ref. 312). Members of the order Archaeogastropoda are mostly gonochoric and broadcast spawners. Life cycle: Embryos develop into planktonic trocophore larvae and later into juvenile veligers before becoming fully grown adults (Ref. 833).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Members of the order Archaeogastropoda are mostly gonochoric and broadcast spawners. Life cycle: Embryos develop into planktonic trocophore larvae and later into juvenile veligers before becoming fully grown adults.
Gallivan, G. and J. Danforth. 1999. (Ref. 312)
IUCN Red List Status (Ref. 115185)
CITES status (Ref. 108899)
Threat to humans
| FishSource |
Estimates of some properties based on models
): 9.5 - 17.9, mean 11.1 (based on 132 cells). | <urn:uuid:7de71210-6174-4965-a210-89a8352222bd> | 3.484375 | 463 | Knowledge Article | Science & Tech. | 55.866825 | 95,514,322 |
Scientists from the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have built and delivered a high-resolution X-ray spectrometer for the largest and most powerful laser facility in the world. The diagnostic, installed on the National Ignition Facility (NIF) at the DOE's Lawrence Livermore National Laboratory, will analyze and record data from high-energy density experiments created by firing NIF's 192 lasers at tiny pellets of fuel. Such experiments are relevant to projects that include the U.S. Stockpile Stewardship Program, which maintains the U.S. nuclear deterrent without full-scale testing, and to inertial confinement fusion, an alternative to the magnetic confinement fusion that PPPL studies.
PPPL has used spectrometers for decades to analyze the electromagnetic spectrum of plasma, the hot fourth state of matter in which electrons have separated from atomic nuclei, inside doughnut-shaped fusion devices known as tokamaks.
The three spectrometer channels inside the instrument.
Credit: Elle Starkman
These devices heat the particles and confine them in magnetic fields, causing the nuclei to fuse and produce fusion energy. By contrast, NIF's high-powered lasers cause fusion by heating the exterior of the fuel pellet. As the exterior vaporizes, pressure extends inward towards the pellet's core, crushing hydrogen atoms together until they fuse and release their energy.
NIF tested and confirmed that the spectrometer was operating as expected on September 28. During the experiment, the device accurately measured the electron temperature and density of a fuel capsule during the fusion process.
"Measuring these conditions is key to achieving ignition of a self-sustaining fusion process on NIF," said PPPL physicist Lan Gao, who helped design and build the device. "Everything worked out very nicely. The signal level we got was just like what we predicted."
The spectrometer will focus on a small capsule of simulated fuel that includes the element krypton to measure how the density and temperature of the hot electrons in the plasma change over time. "The fusion yield is very sensitive to temperature," said Marilyn Schneider, leader of NIF's Radiation Physics and Spectroscopic Diagnostics Group. "The spectrometer will provide the most sensitive temperature measurements to date. The device's ability to plot temperature against time will also be very helpful."
Other PPPL researchers who contributed to this project include Principal Research Physicist Ken Hill; the Head of the Plasma Science & Technology Department Phil Efthimion; and graduate student Brian Kraus.
PPPL, on Princeton University's Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas -- ultra-hot, charged gases -- and to developing practical solutions for the creation of fusion energy. The Laboratory is managed by the University for the U.S. Department of Energy's Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov
Raphael Rosen | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Foundations Of Potential Theory
by Oliver Dimon Kellog
Publisher: Springer 1929
Number of pages: 406
The present volume gives a systematic treatment of potential functions. It takes its origin in two courses, one elementary and one advanced, which the author has given at intervals during the last ten years, and has a two-fold purpose: first, to serve as an introduction for students whose attainments in the Calculus include some knowledge of partial derivatives and multiple and line integrals; and secondly, to provide the reader with the fundamentals of the subject, so that he may proceed immediately to the applications, or to the periodical literature of the day.
Home page url
Download or read it online for free here:
by Willard Miller - Academic Press
The book studies the role played by special function theory in the formalism of mathematical physics. It demonstrates that special functions which arise in mathematical models are dictated by symmetry groups admitted by the models.
by W. Wilson - Dutton
The purpose of the present work is to present an account of the theoretical side of physics which, without being too elaborate, will be sufficiently comprehensive to be useful to teachers and students. This volume deals with mechanics and heat.
by Cumrun Vafa, Eric Zaslow - American Mathematical Society
The book provides an introduction to the field of mirror symmetry from both a mathematical and physical perspective. After covering the relevant background material, the monograph is devoted to the proof of mirror symmetry from various viewpoints.
by Alex Madon - Wikibooks
The goal of this book is to propose an ensemble view of modern physics. The coherence between various fields of physics is insured by following two axes: a first is the universal mathematical language; the second is the study of the N body problem. | <urn:uuid:aac980ab-42ba-44e3-9699-6fd7de3d1c27> | 2.609375 | 364 | Content Listing | Science & Tech. | 24.898624 | 95,514,341 |
An eco-hydrological project on Turkey Creek watershed, South Carolina, U.S.A.
The low-gradient, forested wetland landscape of the southeastern United States’ Coastal Plain represents an important eco-hydrologic system, yet there is a very little information available on the region’s ecological, hydrological and biogeochemical processes. Long-term hydrologic monitoring can provide the information needed to understand basic hydrologic processes and their interactions with climatic variation, ecosystem processes, land use change, and other natural and anthropogenic disturbances. Monitoring also provides researchers with baseline data for evaluating responses, generating new scientific hypotheses, and testing eco-hydrologic models. This information is crucial for the sustainable management of present and future water resources in the southeastern Coastal Plain region, with its growing population, rapidly expanding development, and intensive timber and agricultural industries. This paper presents a multi-collaborative approach for building a monitoring and modeling framework for conducting long-term eco-hydrological studies on a 5,000 ha watershed in the South Carolina Coastal Plain.
You can request print copies of our publications at this email address: firstname.lastname@example.org
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
- Our on-line publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS webmaster if you notice any errors which make this publication unuseable.
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Swift offers three different ways of joining strings. The first is using the
+ operator to join two strings to make a third:
let string1 = "Hello, " let string2 = "world" let combined1 = string1 + string2
The second is user string interpolation to make a new string”
let combined2 = "\(string1) \(string2)"
The last is using the
+= operator to add and assign a string to an existing string:
var combined3 = "Goodbye, " combined3 += "cruel world"
Available from iOS 8.0
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Mon 16th Jul 2018
Seventh Sunday after Trinity
Featured: In Search of the Lost Movado
This entire site Copyright© 1997-2018 Don C. Warrington. All rights reserved.
This routine computes the principal stresses, maximum shear stresses and direction cosines for a set of normal and shear stresses in a solid body. The basic theory is described here, you should familiarise yourself with both of these monographs and their referenced documents:
You can use any system of units as long as it's consistent, i.e, use the same units of stress for all stresses. The routine can calculate results either for the full stress set or the deviatoric one, but you must input the full stresses. | <urn:uuid:ac8dc32d-e394-4bb6-bcbe-631b1de84906> | 2.671875 | 149 | Documentation | Science & Tech. | 53.633966 | 95,514,373 |
NASA News & Feature Releases
Bright Is The New Black: New York Roofs Go Cool
On the hottest day of the New York City summer in 2011, a white roof covering was measured at 42°F cooler than the traditional black roof it was being compared to, according to a study including NASA scientists that details the first scientific results from the city's unprecedented effort to brighten rooftops and reduce its "urban heat island" effect.
The dark, sunlight-absorbing surfaces of some New York City roofs reached 170°F on July 22, 2011, a day that set a city record for electricity usage during the peak of a heat wave. But in the largest discrepancy of that day, a white roofing material was measured at about 42° cooler. The white roof being tested was a low-cost covering promoted as part of Mayor Michael Bloomberg's effort to reduce the city's greenhouse gas emissions 30 percent by 2030.
On average through the summer of 2011, the pilot white roof surface reduced peak rooftop temperature compared to a typical black roof by 43°, according to the study, which was the first long-term effort in New York to test how specific white roof materials held up and performed over several years.
Widespread installation of white roofs, like New York City is attempting through the NYC CoolRoofs program, could reduce city temperatures while cutting down on energy usage and resulting greenhouse gas emissions, said Stuart Gaffin, a research scientist at Columbia University, and lead author on a paper detailing the roof study. The paper published online Mar. 7, 2012, in Environmental Research Letters.
The urban landscape of asphalt, metal, and dark buildings absorbs more energy from sunlight than forests, fields or snow- and ice-covered landscapes, which reflect more light. The absorption leads to what scientists call an "urban heat island," where a city experiences markedly warmer temperatures than surrounding regions. New York City's urban heat island has a more pronounced effect at night, typically raising nighttime temperatures between 5 and 7°F relative to what they would be without the effect, according to Gaffin's previous research.
The problem leads to everything from spikes in electricity usage and greenhouse gas emissions to poorer air quality and increased risk of death during heat waves. In recent years, city planners worldwide have discussed cutting into this effect by converting dark roofs to either "living" roofs covered in plants or to white roofs, the far less expensive option. The options tested in this study included two synthetic membranes requiring professional installation and a do-it-yourself (DIY), white-paint coating that is being promoted by the city's white roof initiative.
"Cities have been progressively darkening the landscape for hundreds of years. This is the first effort in New York to reverse that. It's an ambitious effort with real potential to lower city temperatures and energy bills," said Gaffin. "City roofs are traditionally black because asphalt and tar are waterproof, tough, ductile and were easiest to apply to complex rooftop geometries. But from a climate and urban heat island standpoint, it makes a lot of sense to install bright, white roofs. That's why we say, 'Bright is the new black.'"
With climate change, the urban heat island problem will likely intensify in coming decades, said Cynthia Rosenzweig, a scientist at NASA's Goddard Institute for Space Studies in New York City and a co-author on the paper.
"Right now, we average about 14 days each summer above 90° in New York. In a couple decades, we could be experiencing 30 days or more," Rosenzweig said.
The study found similar temperature reduction when all the surfaces were first installed, but that the professionally installed membranes maintained their reflectivity better over multiple years.
The fraction of incoming solar radiation reflected skyward determines what is called a surface's albedo. The citywide program is in effect an "albedo enhancement" program. In addition to measuring rooftop surface temperature, the study also looked at how the reflectivity and emissivity of the white surfaces held up over time. Reflectivity measures how much light a surface immediately reflects skyward. Emissivity measures how much infrared radiation a surface emits after absorbing solar radiation.
Both the reflectivity and emissivity of the professionally installed white membrane coverings (which cost about $15 to $28 per square foot) held up remarkably well after even four years in use. These surfaces continued to meet Energy Star standards, set by the EPA's Energy Star Reflective Roof program. The effectiveness of the white coating (which only costs about 50 cents per square foot) was about cut in half after two years, ultimately falling below the Energy Star standard. However, Gaffin said, the low-cost surface improved albedo markedly over typical black, asphalt roofs.
"It's the lowest hanging fruit. It's very cheap to do; it's a retro-fit. You don't need a skilled labor force. And you don't have to wait for a roof to be retired," said Gaffin referring to the DIY acrylic method. "So if you really talk about ways in which you brighten urban albedo, this is the fastest, cheapest way to do it."
NASA studies the urban heat island effect to better understand and model how urban surfaces and expanding urbanization might impact regional and global climate, said Marc Imhoff, a biospheric scientist at NASA Goddard Space Flight Center, Greenbelt, Md.
"We're trying to build a capability where we can expand our knowledge with data on more locations, and ultimately develop computer models that would allow us to predict urban heat islands and urban temperatures on a town level," Imhoff said. "Eventually, we could incorporate our findings into large-scale, global climate models."
Gaffin, S.R., M. Imhoff, C. Rosenzweig, R. Khanbilvardi, A. Pasqualini, A.Y.Y. Kong, D. Grillo, A. Freed, D. Hillel, and E. Hartung, 2012: Bright is the new black — multi-year performance of high-albedo roofs in an urban climate. Environ. Res. Lett., 7, 014029, doi:10.1088/1748-9326/7/1/014029.
Leslie McCarthy, NASA Goddard Institute for Space Studies, New York, N.Y., 212-678-5507, firstname.lastname@example.org
This article was originally prepared by Patrick Lynch as a NASA portal Looking at Earth news feature. | <urn:uuid:605e5369-3a58-4061-bae6-726ad3ffbbf0> | 3.40625 | 1,358 | News (Org.) | Science & Tech. | 48.271621 | 95,514,393 |
The hypercube and hypersphere: breaking them down and building them up
September 24, 2013
Bailey Hall 207
Refreshments will be served in Bailey Hall 204 at 4:45
A sphere in three-dimensional space can be broken into two congruent connected pieces in essentially only one way (two hemispheres). In four dimensions, the object that corresponds to the sphere can also be broken into two hemispheres, but can it be formed from two congruent connected pieces in any other way? In this talk, we investigate this question through an analysis of the four-dimensional cube, and use that to develop an interesting decomposition of the four-dimensional sphere that has no analog in three dimensions. Along the way, we learn some techniques for visualizing objects in four dimensions, and view computer images of objects from the fourth dimension. No prior experience with four dimensions is required.
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Comments to: email@example.com
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The .NET runtime enforces role-based security using techniques and syntax similar to those we described in Chapter 7 for code-access security. In your applications, you protect functionality by making role-based security demands that specify the identity or role that the thread's principal must contain. If the thread's principal does not contain the demanded identity and role, then the demand causes an exception.
System.Security.Principal namespace includes
IPrincipal interfaces to represent identities and
principals. By using interfaces to represent identities and
principals, .NET provides flexibility, which means that it is
relatively easy to create concrete role-based security
implementations to support many different authentication and
authorization mechanisms. The .NET class library
contains four concrete RBS
implementations that use the
Provides a role-based authentication mechanism for use in ASP.NET
applications. Forms authentication only provides an implementation of
IIdentity; we discuss Forms authentication in
Provides a generic role-based security implementation that is independent of any specific authentication and authorization mechanism. See Section 10.2.5 for details.
Provides a role-based authentication mechanism that relies on the Microsoft Passport .NET web-based service to authenticate users. ... | <urn:uuid:0f7d1b2f-70cf-4373-bc0c-0877cfcf3e94> | 2.515625 | 266 | Documentation | Software Dev. | 15.13625 | 95,514,451 |
But in a new study, published online October 9, 2006 in The Anatomical Record, the official journal of the American Association of Anatomists, researchers suggest that the remains are, in fact, a Homo sapiens with microcephaly, an abnormally small head. The study is available via Wiley InterScience at http://www.interscience.wiley.com/journal/ar.
The main specimen of the remains, dated at about 18,000 years ago, consists of a skull and partial skeleton from a dentally adult individual (LB1). Using femur length to extrapolate height, the stature of the skeleton was estimated to be 106 cm. Other notable features were the absence of a chin in the jawbone and a very small cranial capacity. In addition to LB1, fragments of eight other individuals were found, along with advanced stone tools. The initial conclusion was that H. floresiensis was a new species, a dwarf derived from Home erectus.
In the current article, Professor Robert D. Martin of The Field Museum in Chicago, IL, and colleagues painstakingly analyze the anatomy of the remains in order to put forth the case that they are H. sapiens that had suffered from some kind of pathology. Although the original paper following the discovery dismissed the idea of microcephaly because the skeletal features did not seem to fit with this condition, the authors note that the skeleton displays many features of syndromes of microcephaly in modern man, of which there are more than 400 types often associated with severe short stature. They note that whatever condition afflicted the individual would not have prevented survival to adulthood, which is entirely possible with certain forms of microcephaly. According to their analysis, if the height, body mass, head circumference, and other anatomical anomalies attributed to H. floresiensis were compared to modern human standards, the result would be a believable, although malformed, individual. "All of these abnormalities taken together would lead to diagnosis of a severe short stature with microcephaly syndrome, although data are not sufficient to match this to a specific known syndrome," the authors state. They also point out that all microcephaly syndromes typically derive from an autosomal recessive gene and can easily recur in a small, inbred population, which would explain the presence of more than one specimen on an isolated island. In addition, they analyze several microcephalic syndromes that could be applied to the LB1 skull. "We find that this group of syndromes shares several features with the LB1 fossil, including very similar small stature and head size, a small and receding jaw, and dental anomalies," they write.
With regard to the stone tools found near the specimens, the authors note that they "clearly belong to types that are consistently associated with Homo sapiens and have not previously been associated with H. erectus or any other early hominid." In fact, they find it questionable whether H. erectus ever made his way to Flores, as the main evidence for his arrival, namely stone tools found in another location but dated much earlier, is equivocal. The authors conclude that "the features of LB1 best support the interpretation that it is a pathological, microcephalic specimen of Homo sapiens."
David Greenberg | EurekAlert!
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
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DescriptionAn introduction to multivectors, dyadics, and differential forms for electrical engineers
While physicists have long applied differential forms to various areas of theoretical analysis, dyadic algebra is also the most natural language for expressing electromagnetic phenomena mathematically. George Deschamps pioneered the application of differential forms to electrical engineering but never completed his work. Now, Ismo V. Lindell, an internationally recognized authority on differential forms, provides a clear and practical introduction to replacing classical Gibbsian vector calculus with the mathematical formalism of differential forms.
In Differential Forms in Electromagnetics, Lindell simplifies the notation and adds memory aids in order to ease the reader's leap from Gibbsian analysis to differential forms, and provides the algebraic tools corresponding to the dyadics of Gibbsian analysis that have long been missing from the formalism. He introduces the reader to basic EM theory and wave equations for the electromagnetic two-forms, discusses the derivation of useful identities, and explains novel ways of treating problems in general linear (bi-anisotropic) media.
Clearly written and devoid of unnecessary mathematical jargon, Differential Forms in Electromagnetics helps engineers master an area of intense interest for anyone involved in research on metamaterials.
1.1 The Grassmann algebra.
1.2 Vectors and dual vectors.
1.5 Geometric interpretation.
2 Dyadic Algebra.
2.1 Products of dyadics.
2.2 Dyadic identities.
2.4 Inverse dyadic.
2.5 Metric dyadics.
2.6 Hodge dyadics.
3 Differential Forms.
3.2 Differentiation theorems.
3.4 Affine transformations.
4 Electromagnetic Fields and Sources.
4.1 Basic electromagnetic quantities.
4.2 Maxwell equations in three dimensions.
4.3 Maxwell equations in four dimensions.
4.5 Super forms.
5 Medium, Boundary, and Power Conditions.
5.1 Medium conditions.
5.2 Conditions on boundaries and interfaces.
5.3 Power conditions.
5.4 The Lorentz force law.
5.5 Stress dyadic.
6 Theorems and Transformations.
6.1 Duality transformation.
6.3 Equivalence of sources.
7 Electromagnetic Waves.
7.1 Wave equation for potentials.
7.2 Wave equation for fields.
7.3 Plane waves.
7.4 TE and TM polarized waves.
7.5 Green functions.
Appendix A: Multivector and Dyadic Identities.
Appendix B: Solutions to Selected Problems.
About the Author. | <urn:uuid:0e8df15d-0ec7-490c-87aa-2eae180f7416> | 3 | 564 | Product Page | Science & Tech. | 44.294781 | 95,514,531 |
In a new paper published in the Nanoletters journal, scientists from the University of Valencia point to a new family of materials with promising applications in solid-state cooling.
When Thomas Edison wanted a filament for his light bulb, he scoured the globe collecting thousands of candidates before settling on bamboo. (It was years before people were able to make tungsten work properly.) That's our ...
A Dartmouth College scientist and his collaborators have created an artificial protein that organizes new materials at the nanoscale.
Research scientists at INM - Leibniz-Institute for New Materials have developed luminous particles that can also withstand high temperatures. When activated by UV light or x-rays, they glow orange red.
New robotic gripping surface for sensitive devices adds a new dimension to handling: a boost for Industry 4.0
Components with highly sensitive surfaces are used in automotive, semiconductor, display and optical technologies.
Thermoelectric materials, which can directly and reversibly convert heat to electrical energy, are used in a variety of applications, including cooling of electronic devices and waste heat energy conversion.
A new technology that is easy to manufacture and uses commercially available materials makes it possible to continuously remove oils and other pollutants from water, representing a potential tool for environmental cleanup.
The INM – Leibniz Institute for New Materials has joined forces with a manufacturer of analytical equipment to reduce particles losses and avoid false negatives.
In 2004 British national Dhiren Barot was arrested for conspiring to commit a public nuisance by the use of radioactive materials, among other charges. Authorities claimed that Barot had researched the production of "dirty ... | <urn:uuid:9d374970-7cb6-42e8-ba30-378330ffb8e3> | 2.78125 | 337 | Content Listing | Science & Tech. | 21.575763 | 95,514,566 |
The age of the central star is estimated from gyrochronology
to be 100-300 Myr.
Washington, July 12 ( ANI ): A new technique called gyrochronology
has helped the scientists to determine the accurate ages of the Sun-like stars from its rotation period.
TEHRAN (FNA)- A team of astronomers devised a new technique to measure the age of a star by using its spin -- gyrochronology.
Since the stars had a known age, astronomers could use them to calibrate the gyrochronology "clock".
If a relationship between stellar rotation and age can be established by studying stars in clusters, then measuring the rotation period of any star can be used to derive its age -- a technique called gyrochronology | <urn:uuid:77667e38-95ea-4e5d-9757-3b215ed6b0d3> | 3.84375 | 157 | News Article | Science & Tech. | 23.902446 | 95,514,573 |
10 Bizarre Discoveries That Scientists Can’t Explain
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A lot of discoveries can be easy to explain, while other discoveries remain a total mystery. There are some things that simply have no explanation for why they exist at all. And we’re not sure why our own brain kills its own cells, but one thing is certain, you will walk away from this thinking the universe is stranger than you thought.
10. Lizard Fish – In the depths of the ocean’s abyss lurks the world’s deepest living superpredator, the Lizard Fish. It resembles something from a horror creature film. It’s given its name Bathysaurus ferox, which means “fierce deep-sea lizard” from its lizard shaped head, which is mostly mouth filled with hinged teeth.
9. Secret subatomic event – A pair of physicists demonstrated that two tiny particles called bottom quarks could fuse together in a powerful flash. The resulting quarksplosion would be more powerful than individual nuclear fusion reactions such as those in the cores of hydrogen bombs.
8. Killing neurons – A new study has shown that as we learn, a burst of new cells is created to help the brain deal with the new information. When this happens, the brain decides which of the new cells work the best while getting rid of the extras that it doesn’t need in a survival-of-the-fittest contest.
7. Fierce female Viking – A high status Viking warrior’s bones were found inside a grave and most believed it to be the burial site of a great male Viking warrior. You would think this since throughout history, most great warriors were male.
6. The elongated skulls of Paracas in Peru – Paracas is a desert peninsula located on the south coast of Peru. In 1928 a massive and elaborate graveyard was found here that had tombs filled with the remains of individuals who had the largest elongated skulls ever found.
5. A huge stone sphere discovered in mid-March 2016 in Bosnia – Many prehistoric stone balls have been discovered in Europe. But none as big as the ball uncovered in Bosnia.
4. Two-headed flatworm – Researchers have sent a lot of animals to space and have been doing this for decades. But something unexpected happened when a flatworm that was sent to space came back with two heads.
3. Huge jelly blobs spotted off norway coast – Mysterious jelly blobs suddenly appeared off of the coast of Norway and nobody has been able to identify what they are. Some experienced divers have reported seeing mysterious 1-meter, or 3.3 feet wide diameter jelly-like blobs. Could they be eggs? Aliens?
2. The Giant Stone Balls of Costa Rica – These giant stone balls that were found in Costa Rica are considered a great unsolved archeological mystery.
1. Dark matter – To pinpoint exactly what dark matter is will leave you with more questions that are unknown that what is known about the subject. But now it is thought that dark matter is ordinary neutrons that have decayed. | <urn:uuid:bf9c41f7-694d-46e0-ad3e-e9d8ffc5f148> | 2.96875 | 663 | Listicle | Science & Tech. | 61.58543 | 95,514,585 |
Quantum chromodynamics binding energy
The quantum chromodynamics binding energy (QCD binding energy), gluon binding energy or chromodynamic binding energy is the energy binding quarks together into hadrons. It is the energy of the field of the strong force, which is mediated by gluons. QCD binding energy can have positive or negative contribution to hadron's mass.
Source of mass
Most of the mass of hadrons is actually QCD binding energy, through mass-energy equivalence. This phenomenon is related to chiral symmetry breaking. In the case of nucleons – protons and neutrons – QCD binding energy forms about 99% of the nucleon's mass. That is if assuming that the kinetic energy of the hadron's constituents, moving at near the speed of light, which contributes greatly to the hadron mass, is part of QCD binding energy. For protons, the sum of the rest masses of the three valence quarks (two up quarks and one down quark) is approximately 9.4 MeV/c2, while the proton's total mass is about 938.3 MeV/c2. For neutrons, the sum of the rest masses of the three valence quarks (two down quarks and one up quark) is approximately 11.9 MeV/c2, while the neutron's total mass is about 939.6 MeV/c2. Considering that nearly all of the atom's mass is concentrated in the nucleons, this means that about 99% of the mass of everyday matter (baryonic matter) is, in fact, chromodynamic binding energy.
While gluons are massless, they still possess energy – chromodynamic binding energy. In this way, they are similar to photons, which are also massless particles carrying energy – photon energy. The amount of energy per single gluon, or "gluon energy", cannot be calculated. Unlike photon energy, which is quantifiable, described by the Planck-Einstein relation and depends on a single variable (the photon's frequency), no formula exists for the quantity of energy carried by each gluon. While the effects of a single photon can be observed, single gluons have not been observed outside of a hadron. Due to the mathematical complexity of quantum chromodynamics and the somewhat chaotic structure of hadrons, which are composed of gluons, valence quarks, sea quarks and other virtual particles, it is not even measurable how many gluons exist at a given moment inside a hadron. Additionally, not all of the QCD binding energy is gluon energy, but rather, some of it comes from the kinetic energy of the hadron's constituents. Therefore, only the total QCD binding energy per hadron can be stated. However, in the future, studies into quark-gluon plasma might be able to overcome this.
- Current quark and constituent quark
- Strong force
- Quantum chromodynamics
- Chiral symmetry breaking
- Photon energy
- Invariant mass and relativistic mass
- Binding energy
- Strassler, Matt (15 April 2013). "Protons and Neutrons: The Massive Pandemonium in Matter". Of Particular Significance. Retrieved 30 May 2016.
- Cho, Adrian (2 April 2010). "Mass of the Common Quark Finally Nailed Down". Science Magazine. AAAS. Retrieved 30 May 2016. | <urn:uuid:9572ce58-f882-46fa-81c3-a4330f3b87ea> | 3.484375 | 718 | Knowledge Article | Science & Tech. | 49.875081 | 95,514,608 |
Latest posts by H. Sterling Burnett (see all)
- Paris Climate Participants Miss Targets While U.S. Reduces Its Emissions - July 12, 2018
- Pope Francis’s Misguided War on Fossil Fuels - July 6, 2018
- Climate Fight Loses a Warrior - July 1, 2018
Time and again, climate models and the outlandish claims made based upon them are found wanting when confronted with hard data and real world experimentation as opposed to unverified assumptions.
The latest evidence of the weaknesses of arguments supporting the idea of dangerous anthropogenic climate change comes from studies of sea levels and cosmic rays.
Two new studies by Australian researchers Albert Parker and Clifford D. Ollier, published in the journal Earth Systems and Environment, call into question estimates used by the United Nations (UN) to back its claim human-caused climate change is increasing the rate of global sea level rise.
One study, using sea level measurements in three locations around the Indian Ocean dating back to the 1800s, discovered the raw sea level measurements show no rise in sea levels. This contrasts with UN claims Indian Ocean sea levels have risen dramatically. The UN’s sea level rise estimates rely on data from the UK’s Permanent Service for Mean Sea Level (PSMSL). PSMSL claimed raw data were insufficient for accurate coverage, and thus it “adjusted” the data to reflect measurements at other locations. Parker and Ollier show the adjustments were done in “arbitrary” ways, using methods that consistently show higher sea levels than are actually measured.
“The adjustments are always in the direction of increasing the alarm,” Ollier told Fox News. “If the raw data show no alarming rise, and you want to create an alarm, you have to alter the raw data.”
Parker and Ollier’s second study shows the UN often uses data from locations with only short-term records, which miss large scale, long-term, decadal and multi-decadal oscillations that shift sea levels upwards and downwards. Using multiple analyses of tide gauges along the U.S. Pacific and Atlantic coasts, the researchers show when these oscillations are accounted for sea levels have experienced on average a much more modest rise since the beginning of the twentieth century than estimated by the UN.
“Limited data from limited areas of study are … unsuitable for making predictions about the whole world sea level. Yet, people continue to make such predictions, often on an alarming scale,” write Parker and Ollier. “Without incorporating these oscillations, it is impossible to make useful assessments of present global accelerations and reliable predictions of future changes of sea level. Furthermore, it is well known that local sea-level changes occur also because of local factors such as subsidence due to groundwater or oil extraction, or tectonic movements that may be either up or down.”
Ollier estimates sea levels are rising only half as fast (about half a foot per century) as claimed by the UN. He says much if not all of the sea level rise may be due to entirely natural factors.
The significance of clouds on climate cannot be debated but their significance when compared to the significance of carbon dioxide just became better understood, and claims concerning the dominance of carbon dioxide suffered a beat down.
New research published in Nature Communications seems to confirm the sun’s role in climate is underestimated by climate models. Climate models assume solar activity has a direct but minimal effect on global temperatures and climate. This research is the first to use experimental data to confirm a powerful indirect effect of solar and cosmic activity on Earth’s climate.
The data indicate cosmic rays from supernovae, and from fluctuations in solar irradiance, lead to changes in cloud formation on Earth, producing an effect five to seven times stronger than the direct effect of changes solar irradiance alone.
The experiments show as cosmic rays increase so does cloud cover, and visa-versa. As clouds increase, they block the amount of sunlight and solar radiation reaching Earth’s surface and trap some amount of outgoing radiation, with more clouds on balance having a cooling effect. The Intergovernmental Panel on Climate Change admits the causes and consequences of cloud formation are poorly understood, with climate models’ treatment of clouds being one of the primary weaknesses limiting the accuracy of their projections.
The experiments described in Nature show how cosmic rays affect cloud formation: When solar activity is low, more cosmic rays reach Earth, forming more low clouds, and the world is cooler. When the sun is active, fewer cosmic rays reach Earth, fewer low clouds form, and the world warms.
Lead author Henrik Svensmark told the Global Warming Policy Foundation the new research explains why, over geologic time scales, the correlation between climate variation and changes in cosmic rays is much larger and closer than the correlation between climate variation and shifts in greenhouse gases. The idea that carbon dioxide has been controlling climate on long time scales is wrong.
The Medieval Warm Period and Little Ice Age coincide with changes in solar activity, as does the recent pause in rising global temperatures extending from the late twentieth to the early twenty-first centuries, which has occurred during a time of remarkably low solar activity.
“[This research] gives a physical foundation to the large body of empirical evidence showing that solar activity is reflected in variations in Earth’s climate,” said Svensmark in a media statement accompanying the release of the Nature study. “For example, the Medieval Warm Period around year 1000AD and the cold period in the Little Ice Age 1300-1900 AD both fit changes in solar activity,”
The Australian reports Svensmark concluding, “The logical consequence is that the climate sensitivity of [carbon dioxide] is smaller than what climate models suggest …, since both carbon dioxide and solar activity has had an impact.” | <urn:uuid:920a7ef0-13eb-4494-81ba-17188dcd98e1> | 2.859375 | 1,215 | News (Org.) | Science & Tech. | 30.26951 | 95,514,614 |
The NASA/ESA Hubble Space Telescope is providing astronomers with extraordinary views of comet 73P/Schwassmann-Wachmann 3 as it disintegrates before our eyes. Recent Hubble images have uncovered many more fragments than have been reported by ground-based observers. These observations provide an unprecedented opportunity to study the demise of a comet nucleus.
Hubble Space Telescope is providing astronomers with extraordinary views of Comet 73P/Schwassmann-Wachmann 3. The fragile comet is rapidly disintegrating as it approaches the Sun. Hubble images have uncovered many more fragments than have been reported by ground-based observers. These observations provide an unprecedented opportunity to study the demise of a comet nucleus. The comet is currently a chain of over 33 separate fragments, named alphabetically, stretching across the sky by several times the angular diameter of the Moon. Hubble caught fragment B during three days shortly after large outbursts in activity (from top to bottom: 18 April, 19 April and 20 April). Hubble shows several dozen "mini-comets” trailing behind each main fragment, probably associated with the ejection of house-sized chunks of surface material. Deep-freeze relics of the early Solar System, cometary nuclei are porous and fragile mixes of dust and ices that can break apart due to the thermal, gravitational, and dynamical stresses of approaching the Sun. Whether any of the many fragments survive the trip around the Sun remains to be seen in the weeks ahead. Credit: NASA, ESA, H. Weaver (APL/JHU), M. Mutchler and Z. Levay (STScI)
Amateur and professional astronomers around the world have been tracking the spectacular disintegration of 73P/Schwassmann-Wachmann 3 for years. As it plummets towards a close encounter with the Sun, swinging round the Sun on 7 June and heading away to begin another loop round the Solar System, the comet will pass the Earth on 12 May, at a distance of 11.7 million kilometres, or 30 times the distance between Earth and the Moon.
The comet currently comprises a chain of over 33 separate fragments, named alphabetically, and stretching across several degrees on the sky (the Sun and Moon each have an apparent diameter of about 1/2 a degree). Ground-based observers have noted dramatic brightening events associated with some of the fragments indicating that they are continuing to break up and that some may disappear altogether.
Lars Christensen | alfa
First evidence on the source of extragalactic particles
13.07.2018 | Technische Universität München
Simpler interferometer can fine tune even the quickest pulses of light
12.07.2018 | University of Rochester
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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13.07.2018 | Life Sciences | <urn:uuid:e0ee28b4-8438-4456-be88-942a784199cf> | 3.78125 | 1,134 | Content Listing | Science & Tech. | 39.747279 | 95,514,629 |
Introduction: How to Perform the Genie in a Bottle Demonstration
This Demonstration shows the catalytic decomposition of hydrogen peroxide.
100mL of 30% hydrogen peroxide is pour into a flask that is wrapped in aluminum foil. A small packet of 2 grams of manganesse dioxide MnO2 is wedged between the rubber stopper and the rim of the glass. When opened the packet releases and the reaction starts.
*****Important Note- There must be hole in the rubber stopper (use a 1 hole or two holed rubber stopper) incase the MnO2 reacts prematurely with the H2O2. It is not a sealed container and will not explode.
Bomber907 made it! | <urn:uuid:12d772bd-f548-4f30-9cc4-88e41ba03a9d> | 3.1875 | 149 | Tutorial | Science & Tech. | 50.198962 | 95,514,639 |
Report on Erta Ale (Ethiopia) — April 2018
Bulletin of the Global Volcanism Network, vol. 43, no. 4 (April 2018)
Managing Editor: Edward Venzke. Report research and preparation by: Liz Crafford.
Erta Ale (Ethiopia) New eruptive event forms lava lake and multiple large flow fields 3 km S of South Pit Crater, January 2017-March 2018
Please cite this report as:
Global Volcanism Program, 2018. Report on Erta Ale (Ethiopia). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 43:4. Smithsonian Institution.
13.6°N, 40.67°E; summit elev. 613 m
All times are local (unless otherwise noted)
Ethiopia's Erta Ale basaltic shield volcano has had at least one active lava lake since the mid-1960s, and possibly much earlier. Two active craters (North Pit and South Pit) within the larger oval-shaped Summit Caldera have exhibited periodic lava fountaining and lava lake overflows over the years. A new eruptive event located about 3 km SE of the Summit Crater appeared on 21 January 2017. Activity at the eruption site increased during subsequent months, sending lava flows several kilometers NE and SW from a newly formed lava lake. This report discusses activity from February 2017 through March 2018 as the flows traveled as far as 16 km from the main vent. Information comes from satellite thermal and visual imagery, and photographs and reports from ground-based expeditions that periodically visit the site.
Summary of activity, February 2017-March 2018. The 21 January 2017 activity at Erta Ale was the first time a vent outside of the Summit Caldera has been observed (figure 50). The initial vent or vents created multiple lava flows that traveled generally NE and SW from their sources, creating at least one lava lake that persisted for about a year (figure 51). The flows began inside an older caldera at a location about 3 km SE of the South Pit Crater, but eventually overflowed the caldera rim in multiple directions. As the flow fields enlarged, thermal imagery captured hot-spots along the flows that were likely produced by breakouts, skylights into lava tunnels, and hornitos, as well as multiple surges of flows across the growing fields (figure 52). The imagery also showed the locations of the advancing flow fronts which had reached over 5 km SW of the source by August 2017 and over 16 km NE of the source by March 2018, eventually reaching the alluvial plain NE of Erta Ale. Thermal anomaly data indicated that the maximum thermal energy output happened in April 2017, gradually decreasing through March 2018. The far NE front of the northeast flow field was still active at end of March 2018.
When the new eruptive episode began, the lava lake at the South Pit Crater drained rapidly to around 80-100 m below the rim, according to visitors to the site a few weeks later. The crater was emitting a strong thermal signal by early March 2017 as the lake level rose again. Visitors in April witnessed a fluctuating lake level rising and falling by up to 20 m every 30 minutes over several days. The thermal signal remained strong at the South Pit Crater through March 2018. Due to significant political instability in the area, ground visits are intermittent, but high-quality photographs were taken in February 2017, December 2017, and January 2018 that show the new lava lake and parts of the new flow fields.
Activity during late January-March 2017. The new eruptive event at Erta Ale began in late January 2017 at the northern end of the Southeast Caldera located; the first lava flows observed were locatedabout 3 km SE from the main Summit Caldera (figure 45 (BGVN 42:07) and figure 50). Two separate vent areas appeared active initially. The northern vent sent lava flows to the NE for several kilometers and to the SW a much shorter distance. The southern vent sent a stream of lava to the S. By the end of January 2017 the North and South Pit Craters at the Summit Caldera were still thermally active, but the signals were much stronger from the new vent areas in the Southeast Caldera (figure 53). A faint thermal signal from about 5 km E of the northern vent suggested the extent of the new flows in that direction.
A small group of travelers led by Ethiopian geologist Enku Mulugeta visited Erta Ale during the first half of February 2017. They reported that within the main Summit Caldera, the hornito in the North Pit Crater had collapsed and the lava lake in the South Pit Crater was about 80-100 m below the caldera floor level. The eruption in the Southeast Caldera was still very active, and they photographed the sizable new lava field which contained numerous pahoehoe flows, actively spattering hornitos, and a large lava lake (figures 51, 52, and 54). During the following months activity remained high both at the new eruption site and at the Summit Caldera where the lava lake in the South Pit Crater gradually rose back up to about 50 m below the caldera floor. Culture Volcan annotated a series of Sentinel-2 satellite thermal images which show the progression of the lava flows through the following year.
By 10 March 2017 only the southern vent area was active inside the Southeast Caldera. It continued to feed the lava field; lava was actively flowing S from the vent towards the W rim of the Southeast Crater, and NE, breaking out from lava tubes which blocked the thermal signal until about 2.6 km NE of the vent (figure 55). Thermal signals from both the North and South Pit Craters were distinct and stronger than in late January.
A site visit to the South Pit Crater on 20 March 2017 demonstrated that the lake level had risen significantly since its drop in early February, and was once again actively convecting (figure 56). By the end of March 2017, satellite thermal imagery made clear the increasing thermal signal at the South Pit Crater, and in the Southeast Caldera, the major increase in effusion to the NE from the main vent. The width of the flow field had increased to about 1,400 m, and the farthest front was about 3,400 m NE from the vent (figure 57). The lava at the source measured about 180 x 75 m in size, suggesting a lava lake; a smaller overflow to the SW appeared to have reached the W rim of the Southeast Caldera by 30 March 2017 near the area where a new flow had first appeared in a 23 January 2017 satellite image (see figure 46, BGVN 42:07).
Activity during April-May 2017. In the next Sentinel-2 satellite image from 9 April (figure 58), the distance to the farthest front of the lava flow had increased to about 4,600 m from the lava lake, and a new flow had appeared a few hundred meters east of the lake that extended about 1,100 m ENE from its source. Lava also flowed SW from the source to the SW rim of the Southeast Crater, appearing to pond against and flow slightly beyond the rim.
A group visited Erta Ale during 11-15 April 2017 in collaboration with Addis Ababa University geologist Enku Mulugeta. They noted that fluctuating lava lake levels at the South Pit Crater were cycling every 30 minutes or so between 40 and 50 m below the caldera floor (figures 59 and 60). Lava tubes from the walls of the crater would feed the lake with fresh lava after it drained. Two coalesced hornitos, about 7 m high, were present in the NE part of the crater, emitting SO2 gas and occasional lava. At the North Crater Pit, noisy degassing of SO2 from several hornitos at the center of the solidified crust was apparent. Observers at the Southeast Caldera could see the lava lake with the top about 10 m below its crater rim, and minor fountaining during the night, but they were not able to get closer than about 700 m due to the active flows.
|Figure 59. The lava lake level at the South Pit Crater at Erta Ale during April 2017 was fluctuating by 10-20 m every 30 minutes or so. The high-stand of the lava is shown here. Courtesy of Toucan Photo.|
|Figure 60. The lava lake level at the South Pit Crater at Erta Ale during April 2017 was fluctuating by 10-20 m every 30 minutes or so. The low stand of the lava is shown here as the lava drains away. Courtesy of Toucan Photo.|
By the end of April 2017 satellite thermal imagery indicated that the northeast flow field at the Southeast Caldera extended more than 7 km NE from the lake and was curving towards the E (figure 61). The lava lake was still thermally active, as was the South Pit Crater to the NW.
Eleven days later, activity was quite different in the Southeast Caldera. Satellite imagery from 9 May 2017 (figure 62) showed a new, relatively narrow but bright lava flow moving NE for 2-3 km originating in a location slightly NE of the original lava lake; activity farther NE had diminished from the previous image. A subsequent image on 18 May looked similar, but by 19 May the narrow flow had been replaced by a much broader area of thermal anomaly in the region immediately E of the source. By 29 May 2017, the source of the lava appeared to have shifted several hundred meters SE of the earlier location, and a strong thermal signal once again extended NE across the northeast flow field from the new source for about two kilometers (figure 63).
Activity during June-August 2017. The rapidly changing flow field was significantly different again less than two weeks later in satellite imagery captured on 8 June 2017. Lava was flowing N, SE, and S across the northeast lava field, extending beyond the rim of the Southeast Caldera to the N and E. Another very strong thermal signal emerged from the SW corner of the Southeast Caldera where lava was flowing W and S outside the caldera rim forming a new southwest lava field (figure 64).
During June 2017, the most aggressive flow activity contributed to significant growth of the southwest lava field. By 28 June, infrared imaging detected flow fronts 4,500 m SW of the vent; they had extended to about 5,100 m, nearing the base of the SW flank of Erta Ale, by 5 July (figure 65). Flow activity also persisted in the northeast flow field with activity concentrated about 1.5 km NE of the vent on 28 June. Movement increased at the northeast flow field beginning in late June and it had extended to about 3.5 km NE of the lava lake by 5 July 2017.
Significant movement to the NE in the northeast flow field was apparent in satellite images beginning on 21 July 2017; the head of the flow had reached about 9.5 km from the lava lake by 28 July 2017, mostly focused in a narrow channel (figure 66). Activity decreased in the southwest flow field during July; the lava front had advanced only a few hundred meters by the end of July from its position on 5 July.
During August 2017, lava continued to flow from the Southeast Caldera lava lake in two directions. The northeast flow front extended to 12 km from the vent by 17 August and had reached over 14 km by 7 September. The southwest flow field, while it remained in roughly the same area, had a decreased but still significant thermal signature in early September, suggesting continued but diminished activity throughout the period (figures 67).
Activity during September-December 2017. In a Sentinel-2 satellite image from 26 September 2017, it was clear that the South Crater Pit was still thermally active, and that the southwest flow field had largely cooled with only a small area on its NW edge still producing a thermal anomaly (figure 68). In contrast, the northeast flow field had advanced about 1 km in the previous three weeks and was less than a kilometer from the edge of the valley alluvium. It finally reached the edge of the older lava field and began to advance across the alluvium NE of the volcano, more than 16 km from the lava lake, on 16 October 2017 (figure 69). Based on satellite imagery, Cultur Volcan interpreted that activity slowed significantly during November 2017, and while the thermal signal remained strong near the head of the flow, it did not advance significantly across the alluvium.
Visitors to the South Pit Crater in mid-December 2017 reported that its lava lake continued to be active and its level was about 60 m below the rim. They were also able to visit the Southeast Caldera lava lake, 2.7 km SE of the South Pit Crater, and take photographs from its rim; it was about 200 m long and 100 m wide and filled with slowly convecting lava (figures 70, 71). Satellite imagery from 25 December 2017 showed the active lake at the South Pit Crater, the active lake at the Southeast Caldera, and numerous skylights and overflows along the 16-km-long northeast flow field (figure 72).
|Figure 71. The Southeast Caldera lava lake at Erta Ale was slowly convecting during mid-December 2017. Photographed by FB88, courtesy of Culture Volcan (Un point sur l'activité à l'Erta Ale, 31 décembre 2017).|
Activity during January-March 2018. By mid-January 2018 thermal activity was concentrated a few kilometers back from the front of the northeast flow, about 12 km from the lava lake (figure 73). A Volcano Discovery tour group visited during 13-26 January 2018 and was able to access and photograph both the North and South Pit Craters and the new lake and flow fields around the Southeast Caldera with ground-based and aerial drone photography (figures 74-84).
|Figure 80. Lava splashes as it flows into the Southeast Caldera lava lake at Erta Ale in January 2018. Photograph by Anastasia Ganuschenko taken during 13-26 January 2018, courtesy of Volcano Discovery.|
|Figure 81. Downwelling consumes lava inside the Southeast Caldera lava lake at Erta Ale in January 2018. Photograph by Stefan Tommasini taken during 13-26 January 2018, courtesy of Volcano Discovery.|
|Figure 83. Many layers of fresh Pahoehoe lava flows were cool enough to walk on in some areas of the Southeast Caldera lava fields in January 2018. Photograph by Stefan Tommasini taken during 13-26 January 2018, courtesy of Volcano Discovery.|
By late March 2018 no thermal signal appeared in satellite imagery at the site of the Southeast Caldera lava lake, although the South Pit Crater was still visible. A large increase in the area of fresh flows and multiple thermal anomalies were present at the flow front of the northeast lava field 14-16 km from the former lava lake (figure 85). During the second half of March, the flow progressed several hundred meters out into the alluvial plain.
MIROVA thermal anomaly data. The MIROVA thermal anomaly data captures information about the distance of the anomalies from the summit as well as the radiative power released from Erta Ale. Both sets of information agree well with observations from the Sentinel-2 and Landsat satellite data. The plot of distance from the summit (figure 86) shows that during August 2016-mid-January 2017 the thermal anomalies were located very close to the summit point, representing heat flow from both the South and North Pit Craters within the Summit Caldera. Beginning on 21 January 2017, the jump in location of the anomalies corresponded with the beginning of the eruption in the Southeast Caldera. The MIROVA thermal anomalies progressed farther from the summit point during March and April 2017, when the northeast flow field was lengthening to the NE. The thermal signal jumps back closer to the summit point in early May corresponding to when new breakouts were spotted near the Southeast Caldera lava lake; the flows again traveled away from the lake during June and July 2017. Active lava flows from mid-August 2017 through March 2018 were visible in satellite imagery 12-16 km from the lava lake, which is reflected in the MIROVA data (figure 86).
The MIROVA data for the radiative power released from Erta Ale during August 2016-March 2018 also corresponds well with satellite and ground observations (figure 87). The levels of radiative power were moderate and constant during August 2016 to mid-January 2017 when only the lava lake and hornitos at the South and North Pit Craters were active (see also figure 47, BGVN 42:07). A moderate spike in the radiative power corresponds to the overflow of the South Pit Crater during 16-20 January 2017, followed by a large spike in radiative power on 21 January when the eruption started in the Southeast Caldera. This was followed by an extended period of increased radiative power as extensive flow fields formed in the Southeast Caldera. The graph is also able to distinguish the movement of the flows from near the Southeast Caldera lava lake to farther away and then near again during March-June 2017. The radiative power graph from 10 March 2017-9 March 2018 clearly shows a gradual decrease in the amount of radiative power over the period, suggesting a decline in flow activity, which corresponds well to satellite observations.
Geologic Background. Erta Ale is an isolated basaltic shield that is the most active volcano in Ethiopia. The broad, 50-km-wide edifice rises more than 600 m from below sea level in the barren Danakil depression. Erta Ale is the namesake and most prominent feature of the Erta Ale Range. The volcano contains a 0.7 x 1.6 km, elliptical summit crater housing steep-sided pit craters. Another larger 1.8 x 3.1 km wide depression elongated parallel to the trend of the Erta Ale range is located SE of the summit and is bounded by curvilinear fault scarps on the SE side. Fresh-looking basaltic lava flows from these fissures have poured into the caldera and locally overflowed its rim. The summit caldera is renowned for one, or sometimes two long-term lava lakes that have been active since at least 1967, or possibly since 1906. Recent fissure eruptions have occurred on the N flank.
Information Contacts: European Space Agency (ESA), Copernicus (URL: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus; Robert Simon, Sr., Data Visualization Engineer, Planet Labs Inc. (URL: http://www.planet.com/) [Images used under https://creativecommons.org/licenses/by-sa/4.0/]; Cultur Volcan, Journal d'un volcanophile (URL: https://laculturevolcan.blogspot.com); Toucan Photo (URL: www.toucan.photo); Tom Pfeiffer, Volcano Discovery (URL: http://www.volcanodiscovery.com/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/). | <urn:uuid:091460cd-fc03-4c5e-b81e-5e177c3a956e> | 2.53125 | 4,014 | Academic Writing | Science & Tech. | 52.618671 | 95,514,663 |
Gas seepage off Norwegian coast spans hundreds of kilometers
Off the coast of Spitsbergen, on the upper continental margin between Bear Island and Kongsfjord, methane gas is emitted from the seafloor at more than a thousand sites. Past expeditions have reported methane gas seeps off the coast of Prins Karls Forland, presumed by some scientists to be a result of the dissociation of methane hydrates in the sediments caused by warming in recent years.
The Research Vessel HEINCKE at the pier at Ny-Ålesund.
Photo: G. Bohrman/MARUM-Center for Marine Environmental Sciences, University of Bremen
The results of two cruises of the Research Vessel HEINCKE in 2015 have revealed, however, that methane emissions are not limited to this site, but extend across five degrees of latitude along the continental margin, and is very likely associated with the Hornsund Fracture Zone. Susan Mau has now published the results together with her colleagues at MARUM – Center for Marine Environmental Sciences at the University of Bremen, and others from the Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung in Bremerhaven and Oregon State University (USA).
The investigations of Susan Mau and her colleagues are based on data from two research cruises in the summer of 2015. The gas discharge sites were identified hydroacoustically as patterns called “flares.” “We already knew about the gas seeps off Prins Karls Forland because that site has been thoroughly studied,” explains Dr. Mau.
Their data, however, reveal the presence of numerous emission sites along the entire coast. The sites follow a fracture zone on the upper continental margin that could be the conduit for the methane rising from depths along this zone. Like air from a perforated bicycle inner tube submerged in water, the rising gas can escape along the fractures and ascend through the sea water. According to Mau, the scientists measured consistently high methane concentrations along the entire slope off the coast of Svalbard. “But they were especially high at the sites where multiple flares were seen.”
In addition, the gas seepage conspicuously occurred at bathymetrically elevated areas rather than in the troughs between them. Susan Mau presumes the reason for this is fine-grained deposits sealing the pathways that gas could otherwise escape from.
Why have so many emission sites been discovered off Prins Karls Forland? Are there even more sites off the coast of Svalbard? These were the initial questions to be addressed by the cruises led by Susan Mau and Gerhard Bohrmann. Furthermore, rock samples and seismic studies have shown that the entire coast is characterized by similar tectonic conditions and glacial history. The gas seeps verified off the coast of Svalbard are interesting primarily because scientists have thought that the methane escaping here is released from methane hydrates. Methane hydrates have a solid ice-like structure that is only stable under specific pressure conditions at rather well defined depths and relatively low temperatures. When the water becomes warmer methane hydrate is no longer stable and methane is released.
Should the water warm up – due to climate change, for example – methane hydrates can only occur in deeper sediments. The boundary zone in which gas hydrates become stable is effectively shifted downward. The gas bubble emissions observed by Mau and her colleagues, however, also occur above this boundary, and thus are not anthropogenically triggered gas released from methane hydrates.
These methane seepage sites are the result, rather, of large amounts of gas from great depths escaping along the Hornsund Fracture Zone, an extensive fault zone in the Earth’s crust, a natural geologic process. This produces high gas concentrations that the team has confirmed over a range of hundreds of kilometers along the coast. The data from the summer of 2015 also indicate that the dissolved methane is oxidized by microbes within the water column and only a small proportion escapes into the atmosphere. The microbes thus prevent an increase in greenhouse gas concentrations in the atmosphere.
From their current results, numerous new questions arise for the geologists Susan Mau and Gerhard Bohrmann: What is the precise course of the actual fracture zone? What is the character of the substratum? Where are the gas reservoirs located? And: What is the age of the escaping gas? In any case, a connection between the large number of gas seeps and human-produced warming of the oceans has not been confirmed.
Because the expeditions off the coast by Mau and her colleagues were carried out in the summer, it is not certain what happens during other colder and stormier seasons. “Our results cry out for long-term studies of the seeps,” Mau emphasizes. “We have to strive to learn the reason for high methane gas concentrations that have occurred repeatedly throughout the Earth’s history. The goal is to observe the seepage sites to find out what happens over the course of the year. Only then will it be possible to draw accurate conclusions – including, for example, whether gas emissions at these depths and at this temperate zone are climate relevant.”
Dr. Susan Mau
Telephone: +49 (0) 421-21865059
Susan Mau, Miriam Römer, Martha E. Torres, Ingeburg Bussmann, Thomas Pape, Ellen Damm, Patrizia Geprägs, Paul Wintersteller, Chieh-Wei Hsu, Markus Loher und Gerhard Bohrmann: Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden. Sci. Rep. 7, 42997; doi: 10.1038/srep42997 (2017)
Further information / Photo material:
Telephone: 0421 218 65540
Ulrike Prange | idw - Informationsdienst Wissenschaft
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Materials Sciences
18.07.2018 | Life Sciences
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Do the overall efficiencies of renewable energy sources, such as wind, solar, and geothermal add up in terms of their complete life cycle from materials sourcing, manufacture, running, and decommissioning" Researchers in Greece have carried out a life cycle assessment to find the answer.
Increasing energy consumption and a growing world population implies shrinking reserves of fossil fuels. While the use of fossil fuels brings with it the problem of carbon dioxide emissions and climate change. Our continued dependence on fossil fuels coupled with the pressing global issue of climate change has pushed the concept of renewable energy sources to the top of the agenda.
In looking for alternative energy supplies, there is more to simply adding up the outputs, according to Christopher Koroneos and Yanni Koroneos of the Laboratory of Heat Transfer and Environmental Engineering, at the Aristotle University of Thessaloniki, Greece. They argue that a whole life cycle assessment of any environmentally friendly energy supply must be carried out to ensure its green credentials are valid.
Writing in Inderscience's International Journal of Global Energy Issues, the researchers point out that land use and materials employed are just two aspects of renewable energy development that can have an adverse impact on the otherwise positive environmental picture.
There are three viable renewable energy resources, say the researchers - solar energy, wind power and geothermal energy. They have applied the techniques of life cycle assessment (LCA) to each in order to determine the total environmental impact and to compare this with the effects of equivalent energy release from fossil fuels.
The LCA approach allows an assessment to be made of the flow of material and energy used in the construction, operation and ultimate decommissioning of a renewable energy supply. It also takes into account the manufacturing of components, the possible extraction and supply of fuels as well as waste generated in these processes.
The researchers demonstrate that some renewable energy systems based on wind power and geothermal energy do have valid green credentials in electricity production. The efficiency of these systems is comparable over the complete life cycle than the equivalent fossil fuel system. However, the conversion of solar energy to electricity using photovoltaic solar cells is less efficient in terms of materials production, running, and recycling than non-renewable energy. However, economies of scale come into play with solar power and a large enough area of solar cells would outstrip the fossil fuel system. The team also points out that the life cycle pollution of solar systems is much, much lower than any conventional system although thermodynamic efficiency is lower.
"A significant advantage of the use of renewable energy systems," say the researchers, "is that they are environmentally friendly because overall they result in lower dangerous pollutant emissions, this and one other major factor, they are essentially inexhaustible."
Christopher Koroneos | EurekAlert!
New creepy, crawly search and rescue robot developed at Ben-Gurion U
19.07.2018 | American Associates, Ben-Gurion University of the Negev
The role of Sodium for the Enhancement of Solar Cells
17.07.2018 | Max-Planck-Institut für Eisenforschung GmbH
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
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Lapse rate is the rate at which Earth's atmospheric temperature decreases with an increase in altitude, or increases with the decrease in altitude. Lapse rate arises from the word lapse, in the sense of a gradual change.
A formal definition from the Glossary of Meteorology is:
- The decrease of an atmospheric variable with height, the variable being temperature unless otherwise specified.
In general, a lapse rate is the negative of the rate of temperature change with altitude change, thus:
Convection and adiabatic expansion
The temperature profile of the atmosphere is a result of an interaction between radiation and convection. Sunlight hits the ground and heats it. The ground then heats the air at the surface. If radiation were the only way to transfer heat from the ground to space, the greenhouse effect of gases in the atmosphere would keep the ground at roughly 333 K (60 °C; 140 °F), and the temperature would decay exponentially with height.
However, when air is hot, it tends to expand, which lowers its density. Thus, hot air tends to rise and transfer heat upward. This is the process of convection. Convection comes to equilibrium when a parcel of air at a given altitude has the same density as the other air at the same elevation.
When a parcel of air expands, it pushes on the air around it, doing work (thermodynamics). Since the parcel does work but gains no heat, it loses internal energy so that its temperature decreases. The process of expanding and contracting without exchanging heat is an adiabatic process. The term adiabatic means that no heat transfer occurs into or out of the parcel. Air has low thermal conductivity, and the bodies of air involved are very large, so transfer of heat by conduction is negligibly small.
The adiabatic process for air has a characteristic temperature-pressure curve, so the process determines the lapse rate. When the air contains little water, this lapse rate is known as the dry adiabatic lapse rate: the rate of temperature decrease is 9.8 °C/km (5.38 °F per 1,000 ft) (3.0 °C/1,000 ft). The reverse occurs for a sinking parcel of air.
Note that only the troposphere (up to approximately 12 kilometres (39,000 ft) of altitude) in the Earth's atmosphere undergoes convection: the stratosphere does not generally convect. However, some exceptionally energetic convection processes -- notably volcanic eruption columns and overshooting tops associated with severe supercell thunderstorms -- may locally and temporarily inject convection through the tropopause and into the stratosphere.
Mathematics of the adiabatic lapse rate
These calculation use a very simple model of an atmosphere, either dry or moist, within a still vertical column at equilibrium.
Dry adiabatic lapse rate
Thermodynamics defines an adiabatic process as:
the first law of thermodynamics can be written as
Also, since and , we can show that:
Moist adiabatic lapse rate
The presence of water within the atmosphere(usually the troposphere) complicates the process of convection. Water vapor contains latent heat of vaporization. As a parcel of air rises and cools, it eventually becomes saturated; that is, the vapor pressure of water in equilibrium with liquid water has decreased (as temperature has decreased) to the point where it is equal to the actual vapor pressure of water. With further decrease in temperature the water vapor in excess of the equilibrium amount condenses, forming cloud, and releasing heat (latent heat of condensation). Before saturation, the rising air follows the dry adiabatic lapse rate. After saturation, the rising air follows the moist adiabatic lapse rate. The release of latent heat is an important source of energy in the development of thunderstorms.
While the dry adiabatic lapse rate is a constant 9.8 °C/km (5.38 °F per 1,000 ft, 3 °C/1,000 ft), the moist adiabatic lapse rate varies strongly with temperature. A typical value is around 5 °C/km, (9 °F/km, 2.7 °F/1,000 ft, 1.5 °C/1,000 ft). The formula for the moist adiabatic lapse rate is given by:
, wet adiabatic lapse rate, K/m , Earth's gravitational acceleration = 9.8076 m/s2 , heat of vaporization of water = 501000 J/kg2 , specific gas constant of dry air = 287 J/kg·K , specific gas constant of water vapour = 461.5 J/kg·K , the dimensionless ratio of the specific gas constant of dry air to the specific gas constant for water vapour = 0.622 , the water vapour pressure of the saturated air , the pressure of the saturated air , the mixing ratio of the mass of water vapour to the mass of dry air , temperature of the saturated air, K , the specific heat of dry air at constant pressure, = 1003.5 J/kg·K
Environmental lapse rate
The environmental lapse rate (ELR), is the rate of decrease of temperature with altitude in the stationary atmosphere at a given time and location. As an average, the International Civil Aviation Organization (ICAO) defines an international standard atmosphere (ISA) with a temperature lapse rate of 6.49 K/km (3.56 °F or 1.98 °C/1,000 ft) from sea level to 11 km (36,090 ft or 6.8 mi). From 11 km up to 20 km (65,620 ft or 12.4 mi), the constant temperature is −56.5 °C (−69.7 °F), which is the lowest assumed temperature in the ISA. The standard atmosphere contains no moisture. Unlike the idealized ISA, the temperature of the actual atmosphere does not always fall at a uniform rate with height. For example, there can be an inversion layer in which the temperature increases with altitude.
Effect on weather
The varying environmental lapse rates throughout the Earth's atmosphere are of critical importance in meteorology, particularly within the troposphere. They are used to determine if the parcel of rising air will rise high enough for its water to condense to form clouds, and, having formed clouds, whether the air will continue to rise and form bigger shower clouds, and whether these clouds will get even bigger and form cumulonimbus clouds (thunder clouds).
As unsaturated air rises, its temperature drops at the dry adiabatic rate. The dew point also drops (as a result of decreasing air pressure) but much more slowly, typically about −2 °C per 1,000 m. If unsaturated air rises far enough, eventually its temperature will reach its dew point, and condensation will begin to form. This altitude is known as the lifting condensation level (LCL) when mechanical lift is present and the convective condensation level (CCL) when mechanical lift is absent, in which case, the parcel must be heated from below to its convective temperature. The cloud base will be somewhere within the layer bounded by these parameters.
The difference between the dry adiabatic lapse rate and the rate at which the dew point drops is around 8 °C per 1,000 m. Given a difference in temperature and dew point readings on the ground, one can easily find the LCL by multiplying the difference by 125 m/°C.
If the environmental lapse rate is less than the moist adiabatic lapse rate, the air is absolutely stable — rising air will cool faster than the surrounding air and lose buoyancy. This often happens in the early morning, when the air near the ground has cooled overnight. Cloud formation in stable air is unlikely.
If the environmental lapse rate is between the moist and dry adiabatic lapse rates, the air is conditionally unstable — an unsaturated parcel of air does not have sufficient buoyancy to rise to the LCL or CCL, and it is stable to weak vertical displacements in either direction. If the parcel is saturated it is unstable and will rise to the LCL or CCL, and either be halted due to an inversion layer of convective inhibition, or if lifting continues, deep, moist convection (DMC) may ensue, as a parcel rises to the level of free convection (LFC), after which it enters the free convective layer (FCL) and usually rises to the equilibrium level (EL).
If the environmental lapse rate is larger than the dry adiabatic lapse rate, it has a superadiabatic lapse rate, the air is absolutely unstable — a parcel of air will gain buoyancy as it rises both below and above the lifting condensation level or convective condensation level. This often happens in the afternoon mainly over land masses. In these conditions, the likelihood of cumulus clouds, showers or even thunderstorms is increased.
Meteorologists use radiosondes to measure the environmental lapse rate and compare it to the predicted adiabatic lapse rate to forecast the likelihood that air will rise. Charts of the environmental lapse rate are known as thermodynamic diagrams, examples of which include Skew-T log-P diagrams and tephigrams. (See also Thermals).
The difference in moist adiabatic lapse rate and the dry rate is the cause of foehn wind phenomenon (also known as "Chinook winds" in parts of North America). The phenomenon exists because warm moist air rises through orographic lifting up and over the top of a mountain range or large mountain. The temperature decreases with the dry adiabatic lapse rate, until it hits the dew point, where water vapor in the air begins to condense. Above that altitude, the adiabatic lapse rate decreases to the moist adiabatic lapse rate as the air continues to rise. Condensation is also commonly followed by precipitation on the top and windward sides of the mountain. As the air descends on the leeward side, it is warmed by adiabatic compression at the dry adiabatic lapse rate. Thus, the foehn wind at a certain altitude is warmer than the corresponding altitude on the windward side of the mountain range. In addition, because the air has lost much of its original water vapor content, the descending air creates an arid region on the leeward side of the mountain.
- Mark Zachary Jacobson (2005). Fundamentals of Atmospheric Modeling (2nd ed.). Cambridge University Press. ISBN 0-521-83970-X.
- C. Donald Ahrens (2006). Meteorology Today (8th ed.). Brooks/Cole Publishing. ISBN 0-495-01162-2.
- Todd S. Glickman (June 2000). Glossary of Meteorology (2nd ed.). American Meteorological Society, Boston. ISBN 1-878220-34-9. (Glossary of Meteorology)
- Salomons, Erik M. (2001). Computational Atmospheric Acoustics (1st ed.). Kluwer Academic Publishers. ISBN 1-4020-0390-0.
- Stull, Roland B. (2001). An Introduction to Boundary Layer Meteorology (1st ed.). Kluwer Academic Publishers. ISBN 90-277-2769-4.
- Goody, Richard M.; Walker, James C.G. (1972). "Atmospheric Temperatures" (PDF). Atmospheres. Prentice-Hall.
- Danielson, Levin, and Abrams, Meteorology, McGraw Hill, 2003
- "The stratosphere: overview". UCAR. Retrieved 2016-05-02.
- Landau and Lifshitz, Fluid Mechanics, Pergamon, 1979
- Kittel; Kroemer (1980). "6". Thermal Physics. Freeman. problem 11
- "Dry Adiabatic Lapse Rate". tpub.com. Archived from the original on 2016-06-03. Retrieved 2016-05-02.
- Minder, JR; Mote, PW; Lundquist, JD (2010). "Surface temperature lapse rates over complex terrain: Lessons from the Cascade Mountains". J. Geophys. Res. 115: D14122. Bibcode:2010JGRD..11514122M. doi:10.1029/2009JD013493.
- "Saturation adiabatic lapse rate". Glossary. American Meteorological Society.
- "Mixing ratio". Glossary. American Meteorological Society.
- Manual of the ICAO Standard Atmosphere (extended to 80 kilometres (262 500 feet)) (Third ed.). International Civil Aviation Organization. 1993. ISBN 92-9194-004-6. Doc 7488-CD.
- Whiteman, C. David (2000). Mountain Meteorology: Fundamentals and Applications. Oxford University Press. ISBN 0-19-513271-8.
- Beychok, Milton R. (2005). Fundamentals Of Stack Gas Dispersion (4th ed.). author-published. ISBN 0-9644588-0-2. www.air-dispersion.com
- R. R. Rogers and M. K. Yau (1989). Short Course in Cloud Physics (3rd ed.). Butterworth-Heinemann. ISBN 0-7506-3215-1. | <urn:uuid:b902a2b6-b032-4257-b4b0-b69a5bb61b56> | 4.1875 | 2,822 | Knowledge Article | Science & Tech. | 55.460503 | 95,514,705 |
dProg/dT GEFS Landfall Tool – Control and Mean Inland
Frequently Asked Questions:
What does the diagram show?
If you are viewing the Ensemble Control or Mean IVT AR Landfall or Inland AR tool, you are looking at the magnitude of integrated vapor transport (IVT) at different latitudes along the U.S. West Coast from “today” through the next 7 or 16 days at 3-hour increments. The landfall locations are the black dots in the right-most panel. The IVT magnitude is shaded on a scale from <200 kg/m/s to >1000 kg/m/s. The right map-panel graphically depicts the total 16-day time-integrated IVT for that location in millions of kg/m.
If you are viewing either of the Probabilistic AR Landfall Tools, these contain the probability of having “atmospheric river” conditions, (i.e., high water vapor content) at different latitudes along the U.S. West Coast from “today” through the next 7 or 16 days at 3-hour increments. Evidence suggest that IVT magnitudes >250 kg/m/s are typically consistent with “AR conditions”, wheras IVT magnitudes >500 kg/m/s are consistent with strong ARs. The values of 150 kg/m/s should be used for inland locations. The landfall locations are the black dots in the right-most panel. The probability is shaded on a scale from 0% (blue) to 100% (purple).
The diagram also graphically depicts the number of hours a location along the coast may expect to see AR conditions at different fraction thresholds: Gray bars for number of hours with a probability >50%, black bars for number of hours >75%, and red bards for number of hours >99%. The higher this number, the longer AR conditions are likely and the more precipitation may be expected!
Why is this diagram useful?
These diagrams display the magnitude and probability of AR conditions at the coast, and at inland locations, and thereby provide a representation of whether or not high-impact precipitation events may be likely. As displayed, the diagram is also capable of providing information on the timing, landfall, intensity, coastal propagation, inland penetration, and uncertainty of AR conditions.
How do you read the diagram?
The main diagram (left display) is read from *right* to *left* at a given latitude in order to indicate how many days from today AR conditions are likely at the coast. By plotting the display from *right* to *left*, the display shows you “what is in the pipeline” as storm systems generally move from west to east.
What is meant by AR conditions?
AR conditions are defined as vertically integrated water vapor flux values generally exceeding 250 kilograms per meter per second. This threshold is generally associated with a landfalling atmospheric river and is capable of producing precipitation along the coast and in interior locations.
How is the probability determined?
The probability is derived from the National Center for Environmental Prediction (NCEP) Global Forecast System (GFS) Ensemble Prediction System. The NCEP-GFS Ensemble contains 20 perturbed models and one control model. These 21 models all predict variables that can be used to compute the vertically integrated water vapor flux. The number of models that predict “AR conditions” at the grid point along the coast divided by the total number of models (21) is one model’s depiction of the probability of having AR conditions at the coast. Data beyond day-7 are interpolated every 3 hours from six-hour data.
What did the display look like on *some date in the past*?
The diagram is archived with each 6-hour run of the NCEP GFS Ensemble. For past diagrams, please contact the diagram developer, Jason Cordeira, at j underscore cordeira at plymouth dot edu.
Still have more questions?
Please feel free to contact the diagram developer, Jason Cordeira, at j underscore cordeira at plymouth dot edu. | <urn:uuid:cb9acf4c-b0c8-4478-8563-83ca08de2847> | 2.609375 | 865 | Customer Support | Science & Tech. | 53.190576 | 95,514,712 |
I need help understanding how to solve redox equations. If you could explain this to me in simple terms I would really appreciate it. i have a sample problem and can't even get past it. The problem is:
K2CrO4 + Mg + HCl to CrCl3 + KCl + MgCl2 + h2O
I need to know how to make a balanced equation out of this. Thank you very much.© BrainMass Inc. brainmass.com July 16, 2018, 11:47 pm ad1c9bdddf
Redox stands for oxidation reduction reaction. This means that some element in the reaction is oxidized while another is reduced in charge.
1) The first thing you want to do is assign oxidation numbers to all elements. Hydrogen is usually always +1 and oxygen is usually always +2. Potassium charge is +1 because it is in column 1 of the periodic table. Cl charge is -1. Knowing these charges we can find the other two unknown metal charges.
You'll find that Cr's charge in K2CrO4 is +6
CrCl3 --> Cr is +3
Mg --> is a solid and thus 0
MgCl2 --. Mg is +2
Therefore Mg is oxidized by +2, and Cr is reduced by -3...going from ...
This solution is provided in 494 words. It defines redox and provides steps for balancing a redox reaction. | <urn:uuid:6ec492da-5664-4e1c-9344-c437819e0897> | 3.625 | 307 | Q&A Forum | Science & Tech. | 85.258075 | 95,514,750 |
Материал из Антэкология /// Anthecology
Patchiness in the Dispersion of Nectar Resources: Probable Causes
Populations of Delphinium nelsonii have been shown to be patchy with regard to standing crop of nectar available to pollinators (Pleasants and Zimmerman 1979). Plants with relatively large amounts of nectar ("hot plants") are associated with other hot plants while plants with relatively small amounts of nectar ("cold plants") are found near other cold plants. Two possible explanations for this pattern exist: 1. Plants in close proximity to one another may have similar nectar production rates or; 2. The patterns of foraging bumblebees might create the observed nectar distribution pattern. By sampling standing crop of nectar in a D. nelsonii population during periods of both high and low bumblebee abundance evidence was gathered indicating that hot and cold spots are caused by bumblebees. | <urn:uuid:f11184bb-7966-4724-8e3a-140196b046b6> | 3.546875 | 210 | Academic Writing | Science & Tech. | 34.088529 | 95,514,796 |
Rutherford's assistants did all the work. Rutherford's idea was, "well let's see if these guys (Geiger, Marsden etc.) are good at detecting alpha particles scattered from gold foil. Make them look for them at large angles. That sounds like a really difficult task." But then, Geiger and Marsden actually found particles scattered at extreme angles.
Experiment — alpha particles bombarding gold foil (polonium a source)
A small fraction of the α-particles falling upon a metal plate have their directions changed to such an extent that they emerge again at the side of incidence.
Compared, however, with the thickness of gold which an α-particle can penetrate, the effect is confined to a relatively thin layer. In our experiment, about half of the reflected particles were reflected from a layer equivalent to about 2 mm of air. If the high velocity and mass of the a-particle be taken into account, it seems surprising that some of the α-particles, as the experiment shows, can be tamed within a layer of 6 × 10−5 cm. of gold through an angle of 90°, and even more. To produce a similar effect by a magnetic field, the enormous field of 109 absolute units would be required.
Three different determinations showed that of the incident α-particles about 1 in 8000 was reflected, under the described conditions.
Geiger, Fellow, Marsden, 1909
It was left to Rutherford to make conclusions from their observations
did not deviate
|atoms are mostly empty space|
|there's something positive inside the atom|
|a tiny fraction
|a small positively charged region (nucleus)
contains most of the atom's mass
|electrons orbit the nucleus like a planet
orbiting the sun
Rutherford's own words.
§1 The observations, however, of Geiger and Marsden on the scattering of α rays indicate that some of the α particles, about 1 in 20,000 were turned through an average angle of 90 degrees in passing though a layer of gold-foil about 0.00004 cm. thick, which was equivalent in stopping-power of the a particle to 1.6 millimetres of air…. It seems reasonable to suppose that the deflexion through a large angle is due to a single atomic encounter, for the chance of a second encounter of a kind to produce a large deflexion must in most cases be exceedingly small. A simple calculation shows that the atom must be a seat of an intense electric field in order to produce such a large deflexion at a single encounter….
§2 Consider an atom which contains a charge ±Ne at its centre surrounded by a sphere of electrification containing a charge ∓Ne supposed uniformly distributed throughout a sphere of radius R. e is the fundamental unit of charge, which in this paper is taken as 4.65 x 10−10 E.S. unit. We shall suppose that for distances less than 10−12 cm. the central charge and also the charge on the alpha particle may be supposed to be concentrated at a point. It will be shown that the main deductions from the theory are independent of whether the central charge is supposed to be positive or negative. For convenience, the sign will be assumed to be positive. The question of the stability of the atom proposed need not be considered at this stage, for this will obviously depend upon the minute structure of the atom, and on the motion of the constituent charged parts….
§7 In comparing the theory outlined in this paper with the experimental results, it has been supposed that the atom consists of a central charge supposed concentrated at a point, and that the large single deflexions of the α and β particles are mainly due to their passage through the strong central field.
Ernest Rutherford, 1911
- electrons in orbit experience centripetal acceleration
- accelerating charge produces electromagnetic waves, electromagnetic waves transfer energy
- loss of energy would make atoms unstable (electron should spiral into nucleus)
- discrete spectra from energetic electrons
- bohr's major new idea
- quantization of angular momentum in terms of ℏ = h/2π
- electrons occupy stationary states around the nucleus
- restricted momentums lead to restricted radii and energy levels
- transition between energy levels accompanied by emission, absorption of photon. The atom only gains or loses energy when its electrons are transferred from one stationary state to another.
- sommerfeld's major new idea
- electrons form standing waves around the nucleus
- discrete nature of harmonics leads to quantization of angular momentum
- new dilemma
- one dimensional
- does not work for other elements — anything with more than one electron
- there are additional spectroscopic phenomena where discrete lines will split that it cannot explain (to be discussed elsewhere)
- zeeman effect
- hyperfine splitting
- discrete emission/absorption lines correspond to allowed energy level transitions
- kirchhoff rules (kirchhoff-bunsen rules?)
- hot objects produces light with a continuous spectrum
- an energized gas produces light with a discrete spectrum
- a hot object behind a cooler gas produces light with a nearly continuous spectrum with gaps at discrete wavelengths
- atomic spectra are atomic fingerprints or barcodes or another identification analog
- quantum optical effects
- dissociation (ozone, for example)
- photochromism (orthonitrotoluenes, for example)
- cis-trans isomerism (visual purple, for example; tioindigos, anils, and azo compounds)
- shifting of position of double bonds (ergostgerol converts to vitamin D, for example)
- Light Amplification through the Stimulated Emission of Radiation
- Looking At Source Erases Retina
Niels Bohr (1885–1962) Denmark
Let us at first assume that there is no energy radiation. In this case the electron will describe stationary elliptical orbits….
The circumstance that the frequency can be written as a difference between two functions of entire numbers [whole numbers] suggests an origin of the lines in the spectra in question similar to the one we have assumed for hydrogen; i.e. that the lines correspond to a radiation emitted during the passing of the system between two different stationary states.
Neils Bohr, 1913
For this it will be necessary to assume that the orbit of the electron can not take on all values, and in any event, the line spectrum clearly indicates that the oscillations of the electron cannot vary continuously between wide limits….
Let us now try to overcome these difficulties by applying Planck's theory to the problem….
The subject of direct observation is the distribution of radiant energy over oscillations of the various wave lengths. Even though we may assume that this energy comes from systems of oscillating particles, we know little or nothing about these systems. No one has ever seen a Planck's resonator, nor indeed even measured its frequency of oscillation; we can observe only the period of oscillation of the radiation which is emitted. It is therefore very convenient that it is possible to show that to obtain the laws of temperature radiation it is not necessary to make any assumptions about the systems which emit the radiation except that the amount of energy emitted each time shall be equal to hν, where h is the Planck constant and ν f is the frequency of the radiation….
During the emission of the radiation the system may be regarded as passing from one state to another; in order to introduce a name for these states we shall call them "stationary" states, simply indicating thereby that they form some kind of waiting places between which occurs the emission of the energy corresponding to the various spectral lines….
Under ordinary circumstances a hydrogen atom will probably exist only in the state corresponding to n = 1. For this state W will have its greatest value and, consequently, the atom will have emitted the largest amount of energy possible; this will therefore represent the most stable state of the atom from which the system cannot be transferred except by adding energy to it from without.
Niels Bohr, 1913
In a letter to…
There appears to me one grave difficulty in your hypothesis, which I have no doubt you fully realize, namely, how does an electron decide at what frequency it is going to vibrate at when it passes from one stationary state to the other? It seems to me that you would have to assume that the electron knows beforehand where it is going to stop.
Ernest Rutherford, 1913
Only an integral number of wavelengths fit in an allowed electron orbit.
|L = mvr||=||nh|
|L2 = m2v2r2||=||n2h2|
|r = n2||ε0h2||= n2a0|
|C||=||2πr||=||nλ = n||h|
|r = n2||ε0h2||= n2a0|
Bohr radius, a0…
|a0 =||(8.854 × 10−12 C2/Nm2)
|π(1.602 × 10−19 C)2
|a0 =||= 5.293 × 10−11 m|
Thus the diameter of a hydrogen atom in its ground state is approximately 10−10 m, a unit also known as an ångstrom and represented with the symbol Å.
energy levels of hydrogen: total energy is the sum of the kinetic and electric potential energy of the electron
|E = K + U =||1||mev2 −||1||e2|
Replace speed with the equation derived earlier for the speed of an electron in a classical circular orbit. Then simplify.
Replace radius with the equation derived earlier for the radius of an electron in an allowed orbit. Then simplify.
|En = −||1||e2||⎛
|En = −||e4me||1|
|En = −||E1|
ground state energy, ionization energy of hydrogen
or in electron volts
|E1 =||− 2.179 × 10−18 J||= − 13.6 eV|
|1.602 × 10−19 C/e|
energy level changes are followed by the emission of a photon
ΔE = hf
Spectroscopists like wavelengths, which leads to the following funky formula — the Rydberg equation for hydrogen.
It can be derived from the Bohr model.
Rydberg constant, R∞
|R∞ =||(1.602 × 10−19 C)4 (9.109 × 10−31 kg)|
|8(8.854 × 10−12 C2/Nm2)2
|R∞ =||1.097 × 107 m−1|
spectral lines are classified according to the energy level the electron lands on
- Grotthuss-Draper law: Light must be absorbed by a chemical substance in order for a photochemical reaction to take place. Molecules that do not absorb light of a particular frequency will not undergo a photochemical reaction when irradiated at that frequency
- Stark-Einstein law (photoequivalence law): Each photon of light can cause a photochemical reaction of only one light absorbing molecule.
- The amount of photoreaction that takes place is directly proportional to the product of the light intensity and the time of illumination. In other words, more light produces more photoproduct.
Electrons have three-dimensional extent, but the Bohr model assumes the electron to be a one-dimensional standing wave wrapped around the nucleus.
major new idea
electron forms a three-dimensional standing wave around the nucleus, electron clouds, restricted wavelengths (spherical harmonics)
Erwin Schrödinger (1887–1961) Austria, Abhandlungen zur Wellenmechanik. Wave equation for matter reminiscent of Maxwell's equations for electromagnetic waves. The story I heard is that Schrödinger went to Switzerland with two goals: to keep his mistress happy and to derive a wave equation for matter. How successful he was with the former is open to speculation.
full, time-dependent form
|iℏ||∂||Ψ(r,t) = −||ℏ2||∇2Ψ(r,t) + V(r)Ψ(r,t)|
can be separated into two halves
Ψ(r, t) = ψ(r)φ(t)
spatial, time-independent half
|Eψ(r) = −||ℏ2||∇2ψ(r) + V(r)ψ(r)|
The electrons around an atom are standing, probability waves. It's their interference, when atoms bond and form molecules, that determine molecular structures.
- n — energy quantization, linear momentum quantization? (K, L, M, N, O,… originally A, B,… )
principal quantum number
- ℓ — angular momentum quantization (s, p, d, f, g,… sharp, principal, diffuse, fine/fundamental/faint,… )
(reduced? orbital?) azimuthal quantum number
- m (mℓ) — space quantization
magnetic quantum number
- s (ms) — spin quantization (up, down)
spin quantum number
Wolfgang Pauli (1900–1958) Austria — exclusion principle
The ground states of all elements follow the pattern of the excited states in the hydrogen atom. The structure of the periodic table, which was determined empirically, can be derived theoretically from first principles. Chemistry is sccretly a branch of physics.
|1, 2, 3, 4, 5, 6, 7, 8…||0||0||s||spherical|
|2, 3, 4, 5, 6, 7…||1||+1||p||x||dumbbell|
|3, 4, 5, 6…||2||+2||d||xy||double dumbbell|
|−2||d||x2 − y2||double dumbbell|
|4, 5…||3||+3||f||y(3x2 − y2)||flat triple dumbbell|
|−2||f||z(x2 − y2)||quadruple dumbbell|
|−3||f||x(3y2 − x2)||flat triple dumbbell|
|5…||4||−4 to +4||g||many-lobed|
1928: Dirac developed the relativistic quantum theory. Paul Dirac states his relativistic electron quantum wave equation. Charles G. Darwin and Walter Gordon solve the Dirac equation for a Coulomb potential. Paul Dirac combines quantum mechanics and special relativity to describe the electron.
Is this right?
|Ψ(xν) = 0|
- agrees with special relativity (is Lorentz invariant)
- has four solutions
- contains within it the notion of spin up and spin down (the first two solutions)
- predicts the existance of antimatter (the second two solutions)
Dirac showed that there are no stable electron orbits for more than 137 electrons, therefore the last chemical element on the periodic table will be untriseptium (137Uts) also known informally as feynmanium (137Fy). It's full electron configuration would be something like…
or is it… | <urn:uuid:c530dff8-8656-4c30-a968-c7991b729a20> | 3.8125 | 3,272 | Content Listing | Science & Tech. | 44.182405 | 95,514,813 |
University of Rhode Island ecologist Laura Meyerson and colleague Jim Cronin from Louisiana State University conducted an ambitious large-scale National Science Foundation funded study on native and invasive Phragmites australis (common reed) in North America and Europe. They found that the intensity of plant invasions by non-native species can vary considerably with changes in latitude.
“When looking at a continental scale invasion in particular, we can’t assume that the invasion is uniform across the region because of latitudinal differences in species interactions like herbivore pressure and resistance to herbivory,” said Meyerson, URI associate professor of habitat restoration ecology.
“Some biogeographic regions may be more susceptible to invasions while others are more resistant. So, if we don’t look at invasions at a macro scale, such as for an entire continent, we might misinterpret the invasion process and the strength of its impacts.
“Our continental-scale biogeographic perspective allowed us to have some insights into the heterogeneity of invasions that are not possible for smaller scale studies,” she added.
The research was published this month in the journal Ecology.
In their study of native and non-native sub-species of P. australis on both continents, they also found that herbivores feed upon the native Phragmites in North America at a much greater rate than on the invasive Phragmites.
“Our native Phragmites in North America is getting hammered by both native and introduced insects, whereas the invasive Phragmites in North America suffers far less herbivory than it does in its native Europe,” she said. “That’s partly because when invasives are introduced to a new place, they leave their enemies behind and can devote their resources to greater growth.”
To determine whether differences occurred in resistance to herbivory, Meyerson and Cronin surveyed 13 patches of native Phragmites and 17 patches of non-native Phragmites along the East Coast from Canada to Florida. They conducted similar surveys of 21 patches of Phragmites in Europe from Norway to southern Portugal. (The native European species and the invasive non-native species in North America are the same lineage.)
At each site Meyerson and Cronin measured plant biomass and defenses against herbivores and quantified insect damage by galling, chewing and sucking (aphids) insects to measure the effects of herbivory on Phragmites fitness. They found that chewing and galling insects consumed a greater quantity of the native and non-native plants in the southern part of North America, while aphids were more prevalent at higher latitudes.
“Interactions between herbivores and native plants were much stronger than interactions between herbivores and invasive plants at lower latitudes, making the southern region more susceptible to invasive species,” Cronin said. “This means that the invasive plants suffer less herbivory at lower latitudes than the native plants, giving the invasive Phragmites a greater opportunity to invade.
“This pattern weakens at higher latitudes suggesting that herbivores may be more important in limiting invasion success in the north,” he added.
Based on their results, Meyerson and Cronin believe that efforts to identify an insect that could be used as an agent of biocontrol for the invasive Phragmites may do more damage to the native species than to the invasive variety.
“Because we found that all of the insects perform better on the native than on the invasive type, it suggests to us that if a biocontrol is released in North America, it’s going to harm the native Phragmites more than the invasive,” they said. “Our data suggests that it would be ill advised to release a biocontrol agent against Phragmites.”
Public Information Officer
Todd McLeish | newswise
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences | <urn:uuid:0c27fb73-580d-4228-a513-bb3efd2bd15b> | 3.25 | 1,424 | Content Listing | Science & Tech. | 29.824757 | 95,514,815 |
2004 Earth Feature Story
Average Difference in Leaf Area Index for Houston Metro Area between 2001 and 2002.
This 5 kilometer resolution image of the Houston area shows the differences in Leaf Area Index (LAI) as an average for August between 2001 and 2002. MODIS LAI measurements show, that on average for August between 2001 and 2002, leaf area in some areas within Houston decreased, likely associated with development in the metropolitan area. Non-urban areas to the northwest and west of the city show higher LAI values compared to the 2001-2002 average, indicating more vegetation. This slide underscores the importance of using current LAI data (rather than climatological, as is standard) in models like LIS. Credit: NASA/Land Information Systems
Houston Area Temperatures, August 22, 2002
Surface temperature on August 22, 2002 at 20:00 Greenwich Mean Time (GMT) for the Houston area as predicted by the Land Information System (LIS). As shown, the temperatures in the Houston area are 1-2 degrees Kelvin (K) (1.8-3.6 F) warmer than the surrounding areas. The black areas are lakes or water bodies, which are not currently modeled by the Land Information System. Credit: Credit: NASA/Land Information Systems
Satellites and computers are getting so good, that now they can help study human activity on scales as local as ones own neighborhood, and may answer questions concerning how local conditions affect global processes, like water and energy cycles.
NASAs Land Information System (LIS) uses computer models to predict impacts that cities and other local land surfaces might have on regional and global land and atmospheric processes. Dr. Christa Peters-Lidard, Co-Principal Investigator and Project Manager for LIS, at NASAs Goddard Space Flight Center (GSFC) in Greenbelt, Md., gave a presentation on LIS this week at the annual meeting of the American Meteorological Society in Seattle.
Krishna Ramanujan / Rob Gutro | GSFC
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
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Solar Energy News -- ScienceDaily
Solar Energy Information. Read the latest news and techniques for efficient solar photovoltaic power, new solar energy systems and more.
New solar sailing technology for NASA
19 Jul 2018 at 1:50pm
Researchers is taking solar sailing to the next level with advanced photonic materials. This new class of materials could be used to steer reflected or transmitted photons and enable near-Earth, interplanetary and interstellar space travel.
Traveling to the sun: Why won't Parker Solar Probe melt?
19 Jul 2018 at 1:50pm
This summer, NASA's Parker Solar Probe will launch to travel closer to the Sun, deeper into the solar atmosphere, than any mission before it. Cutting-edge technology and engineering will help it beat the heat.
New battery could store wind and solar electricity affordably and at room tem...
19 Jul 2018 at 1:50pm
A new type of flow battery that involves a liquid metal more than doubled the maximum voltage of conventional flow batteries and could lead to affordable storage of renewable power.
How to build efficient organic solar cells
16 Jul 2018 at 8:45am
Twenty-five researchers from seven research institutes have put their heads together to draw up rules for designing high-efficiency organic solar cells.
How gold nanoparticles could improve solar energy storage
12 Jul 2018 at 8:45am
Star-shaped gold nanoparticles, coated with a semiconductor, can produce hydrogen from water over four times more efficiently than other methods - opening the door to improved storage of solar energy and other advances that could boost renewable energy use and combat climate change, according to researchers.
Conductive property of graphene, advancing promise of solar technology
10 Jul 2018 at 7:16am
Researchers have connected a graphene layer with two other atomic layers (molybdenum diselenide and tungsten disulfide) thereby extending the lifetime of excited electrons in graphene by several hundred times. The work may speed development of ultrathin and flexible solar cells with high efficiency.
Salt is key ingredient for cheaper and more efficient batteries
9 Jul 2018 at 7:11am
A new design of rechargeable battery, created using salt, could lead the way for greener energy. Researchers have designed the novel energy store which allows for greater power while also lasting longer than conventional batteries.
New world record for direct solar water-splitting efficiency
5 Jul 2018 at 8:40am
An international team of researchers has now succeeded in raising the efficiency of producing hydrogen from direct solar water-splitting to a record 19 per cent. They did so by combining a tandem solar cell of III-V semiconductors with a catalyst of rhodium nanoparticles and a crystalline titanium dioxide coating.
Bacteria-powered solar cell converts light to energy, even under overcast skies
5 Jul 2018 at 5:42am
Researchers have found a cheap, sustainable way to build a solar cell using bacteria that convert light to energy. Their cell generated a current stronger than any previously recorded from such a device, and worked as efficiently in dim light as in bright light. This innovation could be a step toward wider adoption of solar power in places like British Columbia and parts of northern Europe where overcast skies are common.
Material could help windows both power your home and control its temperature
3 Jul 2018 at 8:28am
Environmentally friendly building trends have boosted the popularity of window coatings that keep heating and cooling costs down by blocking out unneeded parts of sunlight. They have also inspired scientists and engineers to create thin, see-through solar cells to turn windows into miniature electricity generators. Researchers have gone a step further and combined these two functions into one window-compatible material that could double the energy efficiency of an average household.
High performance nitride semiconductor for environmentally friendly photovolt...
3 Jul 2018 at 8:00am
A research team has shown how n-type and p-type copper nitride semiconductors could potentially replace the conventional toxic or rare materials in photovoltaic cells.
The vanishing nuclear industry
2 Jul 2018 at 12:47pm
Could nuclear power make a significant contribution to decarbonizing the US energy system over the next three or four decades? Probably not.
Breakthrough in perovskite solar cell technology
29 Jun 2018 at 7:25am
A new technique has produced the highest performing inverted perovskite solar cell ever recorded.
A milestone on the path towards efficient solar cells: Singlet fission
27 Jun 2018 at 1:03pm
Generating more electricity from solar cells and conducting further research into so-called singlet fission. Singlet fission could considerably boost the efficiency of solar cells -- and thanks to the latest research it is one step closer to becoming possible.
Major challenge in mass production of low-cost solar cells solved
21 Jun 2018 at 9:18am
A team has solved a major fabrication challenge for perovskite cells -- the intriguing potential challengers to silicon-based solar cells. The team reveals a new scalable means of applying the compound PCBM, a critical component, to perovskite cells. | <urn:uuid:c875e3a5-2575-46d6-a141-eabcce45eab8> | 2.765625 | 1,059 | Content Listing | Science & Tech. | 34.156471 | 95,514,838 |
The sea-to-air flux of methane from the blowout at the Deepwater Horizon was measured with substantial spatial and temporal resolution over the course of seven days in June 2010. Air and water concentrations were analyzed continuously from a flowing air line and a continuously flowing seawater equilibrator using cavity ring-down spectrometers (CRDS) and a gas chromatograph with a flame ionization detector (GC-FID). The results indicate a low flux of methane to the atmosphere (0.024 μmol m−2 d−1) with atmospheric and seawater equilibrium mixing ratios averaging 1.86 ppm and 2.85 ppm, respectively within the survey area. The oil leak, which was estimated to contain 30.2% methane by weight, was not a significant source of methane to the atmosphere during this study. Most of the methane emitted from the wellhead was dissolved in the deep ocean.
Mendeley saves you time finding and organizing research
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The bird is traveling for an hour because it takes the two trains 60 minutes to travel 30 km to the point of collision. Since the bird has been flying for 60 minutes and it traveles 1 km per minute, (60 min) * (1 km / min) = 60 km
Recently Asked Questions
- Topic: Limits and Continuity. I have provided the questions as a picture so that the numbers are accurately displayed.
- What is integrated marketing and how does it fit in a marketing plan?
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What was discovered in 1896 by Antoine Henri Becquerel?
What did Marie Curie name Becquerel’s “invisible rays”
Which radioactive element did Marie and Pierre Curie discover in 1898?
Polonium and Radium
What three scientists were awarded with the Nobel prize in 1903?
Antoine Henri, Marie Curie, and Pierre Curie
What holds the nucleus together?
Strong Nuclear Force
Electromagnetic Force of Repulsion
What are two factors that determine if the nucleus will be radioactive?
size of the nucleus, neutron/proton radio
How do the neutrons help to stabilize the nucleus?
By adding to the SNF without adding to the EMF of repulsion.
What elements that are too big to stabilize?
Element 84 and above
True or false: Not all isotopes are radioactive
False, all isotopes are radioactive
What elements can be stabilized?
Elements 83 and below
What is an Alpha Particle?
2 protons and 2 neutrons bonding together – identical to nucleus of a Helium atom
What is a Beta Particle?
Identical to an electron – negative charge
What is the Geiger Counter?
Produces an electric current in the presence of radiation. Tube filled with argon and helium gas under low pressure. Radiation enters tube through a window and removes electrons from gas making positively charged ions. Electrons produce a flashing light and clicking sound.
changes color in the presence of radiation
High energy electromagnetic radiation
the natural level of radiation emitted by the earth, living things, and cosmic rays (not a health risk)
use radiation to kill cancer cells
REMS (Roentgen equivalent man)
unit of measurement used to measure the biological effect to the exposure to radiation
True or False: Do all radioisotopes decay?
Yes, all radioisotopes decay
Measure of the rate of nuclear decay
What is activity measure in?
amount of radiation released by one gram of radium in one second=37 billion nuclear disintegrations/second
Time required for one-half of the radioactive atoms of a substance to decay to products
True or false: Longer the half-life the more stable the isotope
reaction that occurs without external cause
One nucleus colliding with another with enough force to cause a nuclear reaction
Machine used to accelerate nuclear particles to strike a target atom
How many isotopes have been discovered?
a radioisotopes that is incorporated into a molecule and its path can then be followed
uses radioisotopes to determine the age of objects
What does Carbon 14 react with?
reacts with oxygen to form radioactive CO2
What equation did Albert Einstein discover?
E = mc(squared)
Discovered that the nucleus of the atom contained immense energy and stored in concentrated form as matter that is stored in the nucleus of atoms. When mass is changed to energy, enormous amounts of energy are released. This energy is determined by the equation E=mc(squared).
What does the E stand for in E=MC2
Energy produced from the conversion of mass to energy
What does the M stand for in E=MC2
mass lost (converted to energy)
What does the C stand for in E=MC2
Speed of light (3.0 x 10(8th power) m/s
What is the speed of light?
3.0 x 10(8th power) m/s
process by which particles are given off by changes in the nucleus
True or False: Neutrons are always lost
How does a Geiger counter detect radiation
produces electric current by neutral nobel gases
What is Curie
Radiation released by 1 gram of radium by 1 second.
What is Curie used to measure?
Used to measure radioactive decay
What is a chain reaction
Continuous series of fission reactions
What is used in a nuclear power plant to control a chain reaction?
what substance is used as a coolant in a nuclear reaction?
exact amount of U-235
causes rapid chain reactions
Name the two radioactive products of a fission of U-235
Element 141 and 92
What is the least amount of protection needed by a person for each type of radioactive emissions
2 lighter nuclei combine to form a heavier element
What does Nuclear Fusion produce
Produces more energy release, waste free, and abundance of raw materials (hydrogen)
What is the major obstacle to developing controlled nuclear fusion?
extremely high temperatures | <urn:uuid:5ee384ee-90d8-4451-a861-cb99c1ea152d> | 3.6875 | 949 | Content Listing | Science & Tech. | 39.911662 | 95,514,917 |
The combination of erosion and melting ice caps led to a massive increase in volcanic activity at the end of the last ice age, according to new research. As the climate warmed, the ice caps melted, decreasing the pressure on the Earth's mantle, leading to an increase in both magma production and volcanic eruptions. The researchers, led by the University of Cambridge, have found that erosion also played a major role in the process, and may have contributed to an increase in atmospheric carbon dioxide levels.
"It's been established that melting ice caps and volcanic activity are linked - but what we've found is that erosion also plays a key role in the cycle," said Dr Pietro Sternai of Cambridge's Department of Earth Sciences, the paper's lead author, who is also a member of Caltech's Division of Geological and Planetary Science.
"Previous attempts to model the huge increase in atmospheric CO2 at the end of the last ice age failed to account for the role of erosion, meaning that CO2 levels may have been seriously underestimated."
Using numerical simulations, which modelled various different features such as ice caps and glacial erosion rates, Sternai and his colleagues from the University of Geneva and ETH Zurich found that erosion is just as important as melting ice in driving the increase in magma production and subsequent volcanic activity. The results are published in the journal Geophysical Research Letters.
Although the researchers caution not to draw too strong a link between anthropogenic (human-caused) climate change and increased volcanic activity as the timescales are very different, since we now live in a period where the ice caps are being melted by climate change, they say that the same mechanism will likely work at shorter timescales as well.
Over the past million years, the Earth has gone back and forth between ice ages, or glacial periods, and interglacial periods, with each period lasting for roughly 100,000 years. During the interglacial periods, such as the one we live in today, volcanic activity is much higher, as the lack of pressure provided by the ice caps means that volcanoes are freer to erupt. But in the transition from an ice age to an interglacial period, the rates of erosion also increase, especially in mountain ranges where volcanoes tend to cluster.
Glaciers are considered to be the most erosive force on Earth, and as they melt, the ground beneath is eroded by as much as ten centimetres per year, further decreasing the pressure on the volcano and increasing the likelihood of an eruption. A decrease in pressure enhances the production of magma at depth, since rocks held at lower pressure tend to melt at lower temperatures.
When volcanoes erupt, they release more carbon dioxide into the atmosphere, creating a cycle that speeds up the warming process. Previous models that attempted to explain the increase in atmospheric CO2 during the end of the last ice age accounted for the role of deglaciation in increasing volcanic activity, but did not account for erosion, meaning that CO2 levels may have been significantly underestimated.
A typical ice age lasting 100,000 years can be characterised into periods of advancing and retreating ice - the ice grows for 80,000 years, but it only takes 20,000 years for that ice to melt.
"There are several factors that contribute to climate warming and cooling trends, and many of them are related to the Earth's orbital parameters," said Sternai. "But we know that much faster warming that cooling can't be caused solely by changes in the Earth's orbit - it must be, at least to some extent, related to something within the Earth system itself. Erosion, by contributing to unload the Earth's surface and enhance volcanic CO2 emissions, may be the missing factor required to explain such persistent climate asymmetry."
Sarah Collins | EurekAlert!
Global study of world's beaches shows threat to protected areas
19.07.2018 | NASA/Goddard Space Flight Center
NSF-supported researchers to present new results on hurricanes and other extreme events
19.07.2018 | National Science Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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A volcano consists of a fissure or vent in the crust of the earth that allows magma to flow up from below. An open, active volcano will occasionally expel gas and magma through this vent, reducing the pressure in the magma chamber below. If something blocks this vent, however, it can lead to a spectacular eruption and an extremely dangerous situation for anyone nearby.
A vent blockage can occur for internal or external reasons. Sometimes the consistency of the magma flowing to the surface becomes thick and viscous, and ends up plugging the vent as it ascends. In other cases the rim of a volcano may collapse and fall back into the vent, blocking it with debris. In June of 2009, a rockfall partially blocked a major vent of the Kilauea volcano, but other vents relieved the pressure and prevented a major eruption.
Pressure and Eruptions
A blocked vent can prevent material from flowing out of the volcano, but it cannot prevent the upwelling of magma that caused the flow in the first place. In most cases a blockage is only temporary, until the pressure builds up enough to clear the plug. If the blockage is extensive, through either a major cinder cone collapse or a long period of inactivity allowing thick magma to solidify into a solid barrier, the pressure may build up enough to cause an eruption. When this occurs, the forces involved can propel magma, gas and ashes with considerable force, creating a pyroclastic flow.
Types of Eruptions
Volcanoes can erupt in many different ways, and vulcanologists often name them after famous volcanoes that exhibited a given type of eruption. A Vulcanian eruption results in a large cloud of ash and gas high over the volcano, while a Pelean eruption produces avalanches of lava fragments and other pyroclastic material that move very quickly down the slope of the cone. Plinian eruptions are common with major vent blockages: the force projects material and gas over a large distance and creates powerful flows of superheated ash, lava and mud that can completely reshape the environment around the mountain. The eruption of Mount St. Helens in 1980 was a Plinian eruption, and actually blew out the side of the mountain rather than going straight up through the vent.
In some cases, a blocked vent may cause the magma reservoir to redirect its energy to other vents, and the material in the original vent can solidify into rock. If the cinder cone, made up of less dense material, erodes away, it can leave a cylindrical structure of solidified material in its place. Ship Rock in New Mexico is such a plug, left behind when the volcano that spawned it gradually vanished. | <urn:uuid:515fc5bd-48fd-469a-93f4-5ae736baa7b6> | 4.4375 | 559 | Knowledge Article | Science & Tech. | 37.659526 | 95,514,968 |
The UWM team sent plasmids up on a rocket to discover how cosmic radiation affects DNA. The results were surprising.
UWM’s David Kaplan is part of a research team that has shown that yet another prediction by Albert Einstein 100 years ago holds up, even in some extreme conditions in deep space.
The LIGO observations of gravitational wave over the past two years were groundbreaking. Now, UWM astronomers plan to build off that work by employing a new tool to decode more mysteries of the sky.
UWM physicists played important roles in the first-ever observation of the explosive collision of neutron stars. The explosion created gravitational waves, but for the first time astronomers observed light from the same source.
The research has the potential to fundamentally advance our understanding of biological processes inside cells. UWM physicists developed algorithms to reconstruct sequential images of viruses too small to photograph.
UWM physicists are working to help physicians by accurately pinpointing fetal conception.
UWM is leading an effort to turn 54 pulsars into a massive observational array.
New imaging equipment developed at UWM gives scientists previously impossible glimpses of life’s building blocks.
UWM physicists were crucial to the world-renowned discovery of Einstein’s predicted gravitational waves. One year later, here’s what else they hope to find. | <urn:uuid:205b7792-b98b-49a5-a8ad-ab29c04e59b9> | 3.140625 | 271 | Content Listing | Science & Tech. | 37.741009 | 95,515,012 |
The dung-beetle has fallen on hard times. Once worshipped by the Ancient Egyptians its status has now slipped to that of unsung and forgotten hero, the butt of scatological jokes. Yet the dung-beetle is truly heroic.
It is a well known 'fact' that were it not for the dung-beetle the world would be knee-deep in animal droppings, especially those of large herbivores like cows, rhinos and elephants which, because they eat more food, produce more waste. By burying that waste dung-beetles not only remove it from the surface, they improve and fertilise the soil and reduce the number of disease-carrying flies that would otherwise infest the dung.
If the modern dung beetle deserves praise for these global sanitation efforts, then the extinct dung beetles of ancient South America deserve a medal. 30 million years ago the continent was home to what is known to palaeontologists as the South America Megafauna, including some truly giant extinct herbivores: bone covered armadillos the size of a small car, ground sloths 6 metres tall and elephant-sized hoofed-mammals unlike anything alive today. And of course, megafauna would have produced mega-dung! The beetles certainly had their work cut out for them and although the dung-beetles themselves did not fossilize, we know they were fully engaged in business because, amazingly, the results of their activities are preserved as fossil dung balls, some more than 40 million years old, and some as large as tennis balls.
Now palaeontologists in Argentina studying these dung balls have discovered that they have even more to tell us about the ecology of this lost world of giant mammals, but at a rather different scale. In a study published in the latest issue of the journal Palaeontology, Graduate Student Victoria Sánchez and Dr Jorge Genise report traces made by other creatures within fossil dung balls.
"Some of these are just the results of chance interactions" explains Dr Sánchez. "Burrowing bees, for example, dug cells in the ground where the dung balls were buried, and some of these happen to have been dug into the balls. But other traces record the behaviour of animals actively stealing the food resources set aside by the dung beetles. The shapes and sizes of these fossilized burrows and borings in the dung balls indicate that other beetles, flies and earthworms were the culprits. Although none of these animals is preserved in these rocks, the fossil dung balls preserve in amazing detail a whole dung-based ecosystem going on right under the noses of the giant herbivores of 30 million years ago."
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Piecewise linear function
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In mathematics, a piecewise linear function is a real-valued function defined on the real numbers or a segment thereof, whose graph is composed of straight-line sections. It is a piecewise-defined function, each of whose pieces is an affine function.
The function defined by:
is piecewise linear with four pieces. (The graph of this function is shown to the right.) Since the graph of a linear function is a line, the graph of a piecewise linear function consists of line segments and rays.
Fitting to a curve
An approximation to a known curve can be found by sampling the curve and interpolating linearly between the points. An algorithm for computing the most significant points subject to a given error tolerance has been published.
Fitting to data
If partitions are already known, linear regression can be performed independently on these partitions. However, continuity is not preserved in that case. A stable algorithm with this case has been derived.
The notion of a piecewise linear function makes sense in several different contexts. Piecewise linear functions may be defined on n-dimensional Euclidean space, or more generally any vector space or affine space, as well as on piecewise linear manifolds, simplicial complexes, and so forth. In each case, the function may be real-valued, or it may take values from a vector space, an affine space, a piecewise-linear manifold, or a simplicial complex. (In these contexts, the term “linear” does not refer solely to linear transformations, but to more general affine linear functions.)
In dimensions higher than one, it is common to require the domain of each piece to be a polygon or polytope. This guarantees that the graph of the function will be composed of polygonal or polytopal pieces.
Important sub-classes of piecewise linear functions include the continuous piecewise linear functions and the convex piecewise linear functions. In general, for every n dimensional continuous piecewise linear function , there is a
If is convex as well as continuous, then there is a
- Piecewise constant function
- Linear interpolation
- Spline interpolation
- Tropical geometry
- Polygonal chain
- Apps, P., Long, N., & Rees, R. (2014). Optimal piecewise linear income taxation. Journal of Public Economic Theory, 16(4), 523-545.
- Stanley, William D. (2004). Technical Analysis And Applications With Matlab. Cengage Learning. p. 143. ISBN 1401864813.
- Hamann, B.; Chen, J. L. (1994). "Data point selection for piecewise linear curve approximation". Computer Aided Geometric Design. 11 (3): 289. doi:10.1016/0167-8396(94)90004-3.
- Golovchenko, Nikolai. "Least-squares Fit of a Continuous Piecewise Linear Function". Retrieved 6 Dec 2012.
- Vieth, E. (1989). "Fitting piecewise linear regression functions to biological responses". Journal of Applied Physiology. 67 (1): 390–396. PMID 2759968.
- Landwehr, N.; Hall, M.; Frank, E. (2005). "Logistic Model Trees" (PDF). Machine Learning. 59: 161. doi:10.1007/s10994-005-0466-3. | <urn:uuid:3daabc00-f3a2-4411-a40c-ba6ec4a28187> | 2.828125 | 744 | Knowledge Article | Science & Tech. | 53.298359 | 95,515,033 |
Before we move on to the MongoDb injections, we must understand what MongoDb exactly is and why we prefer it over other databases. As MongoDb does not use SQL people assumed it is not vulnerable to any kind of injection attacks. But believe me, no one is born with inbuilt security aspects. We have to implement some logic in order to prevent attacks.
What is MongoDb?
In short MongoDb is an open-source database developed by MongoDb Inc., which stores data in JSON-like documents that can vary in structure. Here related information is stored together for fast query access through the MongoDb query language.
Why to use MongoDb?
Just because everyone wants quick results of the queries,MongoDb is most popular. It gives very high performance (1000 millionsquries/sec). Another reason why MongoDb is more popular is because it excels in many use cases where relational databases aren’t a good fit.For example,applications with unstructured, semi-structured and polymorphic data, as well as applications with large scalability requirements or multi-data center deployments.
Stop! Before go further, If you run any open source application. We are providing a free PenTest for open source projects. Submit your application for evaluation here.
Let’s walk through the injections
In the first case we have a PHP script which shows the username and password corresponding to a particular id.
In the above script you can see the name of the database is security, and the name of collection is users. The u_id parameter is obtained from the GET method, then it is passed to an array which gives us the associated results.Sounds good? Let’s try to put some comparison operators with the array.
Oops..!! It dumped the entire database for us. Can you figure out what went wrong with it? This happened because the inputhttp://localhost/mongo/show.php?u_id[$ne]=2
created the following MongoDb query.
$qry= array(“id” => array(“$ne” => 2))
So accordingly it displayed all the results except id=2 which can be seen from snapshot 1.
Let’s consider another case where the script does the same work as earlier, but in this case we’ll create MongoDb query with findOne method.
We’ll first have a quick look at the working of the findOne method. This method has the following syntax:
This returns the document that satisfies the specified query criteria. For example if we need to find the result associated with id=2,the following command will be fired.
Now let’s have a look at the source code:
Here the key point is to somehow break the query and then fix it again. Can you guess what will happen if we typed the following query?
This will break the query and return the desired parameter. Let’s check the output:
Did you notice it gave us two errors, just because we wanted to access two parameters which really don’t exist? Indirectly this error shows that usernameand password are the parameters in database, and that’s what we want.
As soon as we type the correct parameter instead of something, the error will be removed.
Now let’s say we want to find the name of database. In MongoDb,db.getName()method is used to find the name of the database. So the query will be:
In order to dump the database,we first need to find the name of the collections.The db.getCollectionNames()method is used to find the name of collections in MongoDb.
So, till now we have obtained the name of database and collections. What remains is to find the data inside the users collections which can be done as follows:
Similarly we can have other username and password by changing the parameter inside the function db.users.find(),like
Now that you’re familiar with MongoDb injections, probably you would want to know about the prevention of this kind of injection.
Let’s consider the first case where the parameter is passed to an array. To prevent this injection, we somehow need to stop the execution of comparison operators in the array.So, one of its solution is to use implode() function in the following way:
The implode()function returns a string from the elements of an array. Hence we get only one result corresponding to that particular id instead of all the results.
In the second case we can use addslashes() method so that the query cannot be broken by the attacker. However using regular expression to replace special symbols would be a great idea. You can use the following Regex:
$u_name =preg_replace(‘/[^a-z0-9]/i’, ‘\’, $_GET[‘u_name’]);
Now if we try to break the query, it won’t prompt us with an error.
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Science (from Latin scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
From classical antiquity through the 19th century, science as a type of knowledge was more closely linked to philosophy. In the West, the term natural philosophy encompassed fields of study that are currently associated with disciplines such as classical physics, astronomy and medicine and was a precursor of modern natural sciences (life science and physical science). In the 17th and 18th centuries, scientists increasingly sought to formulate knowledge in terms of laws of nature. Over the centuries, the term science became associated with the scientific method, a systematic way of studying the natural world and particularly in the 19th century, multiple distinguishing characteristics of contemporary modern science began to take shape.
Modern science is typically divided into three major branches that consist of the natural sciences (e.g. biology, chemistry, physics), which study nature in the broadest sense; the social sciences (e.g. psychology, sociology, economics), which study individuals and societies; and the formal sciences (e.g. mathematics, logic, theoretical computer science), which study abstract concepts. There is disagreement, however, on the formal sciences being a science as they do not rely on empirical evidence. Disciplines that use science, such as engineering and medicine, are described as applied sciences.
Science is related to research and is commonly organized by academic and research institutions as well as government agencies and companies. The practical impact of scientific research has led to the emergence of science policies that seek to influence the scientific enterprise by prioritizing the development of commercial products, armaments, health care, and environmental protection.
(A Toroidal LHC ApparatuS
) is one of the five particle detector
, ATLAS, CMS
, and LHCb
) being constructed at the Large Hadron Collider
, a new particle accelerator
. It will be 45 metres long and 25 metres in diameter, and will weigh about 7,000 tonnes. The project involves roughly 2,000 scientists
at 151 institutions in 34 countries. The construction was completed in 2008. The experiment is expected to measure phenomena that involve highly massive particles
which were not measurable using earlier lower-energy
accelerators and might shed light on new theories
of particle physics
beyond the Standard Model
The ATLAS collaboration, the group of physicists building the detector, was formed in 1992 when the proposed EAGLE (Experiment for Accurate Gamma, Lepton and Energy Measurements) and ASCOT (Apparatus with Super COnducting Toroids) collaborations merged their efforts into building a single, general-purpose particle detector for the Large Hadron Collider. The design was a combination of those two previous designs, as well as the detector research and development that had been done for the Superconducting Supercollider.
(February 15, 1564 – January 8, 1642) was an Italian physicist
, and philosopher
who is closely associated with the scientific revolution
. His achievements include improvements to the telescope
, a variety of astronomical observations, the first
laws of motion, and effective support for Copernicanism
. According to Stephen Hawking
, Galileo has contributed more to the creation of the modern natural sciences than anybody else. He is the "father of modern astronomy
," the "father of modern physics
," and the "father of science
." The work of Galilei is considered to be a significant break from that of Aristotle
Did you know... | <urn:uuid:39f25f0c-b418-4b66-a0f5-b9d760d3d44e> | 3.328125 | 724 | Knowledge Article | Science & Tech. | 24.691545 | 95,515,050 |
(Poll and Leleup, 1965) Cohen and Nielson 1978
Caecogilbia galapagosensis Poll and Leleup 1965
Holotype: MRAC uncatalogued male 51.5mm SL. Allotype: female 47.0mm SL. Paratypes: male 39.0mm SL, male 49.0mm SL, male 55mm SL, female 40mm SL, female 48mm SL. Moller et al. (2005) report that no specimens of this species could be found at MRAC, any other major Museum, or the Charles Darwin Station on the Galapagos Islands. This species is the type species by monotypy of the genus Caecogilbia.
Type locality: a number of deep fissures situated between the lagoon of "Flamants roses", about 2 km west of Turtle Bay, close to Charles Darwin Station, Santa Cruz Island, Galapagos (0o37’S, 90o21’W). Grove and Lavenberg (1997:20,224) comment that this species: “... is known only from fresh and brackish waters in crevices on Santa Cruz near Bahia Tortuga [= Turtle Bay] and Punta Las Palmas ...”. Poll and Leleup (1965:464) suggested that the species may be distributed throughout Santa Cruz but this seems unlikely in view the studies of Grove and Lavenberg. Snell, Stone and Snell (1996) summarise the geography of Galapagos and should be consulted by anyone studying there.
Fissures constitute the only points of access to an extensive area of more or less brackish ground water. This probably underlies the whole island in a Ghyben-Herzberg lens but all of the fishes observed were seen between 500 m and 1 km of the coast. The degree of salinity decreases with distance from the sea. This is an anchialine habitat (see Iliffe 1991, 1992, 2000). Individuals appear to live among roots of Cryptocarpus vegetation (DeRoy 1974, Grove and Lavenberg 1997:224). The presumed sister species, Ogilbia deroyi (Poll and Van Moll 1966), inhabits: “...loose rocks and boulders in shallow intertidal water...” (Grove and Lavenberg 1997:221). The comparative ecology of O. galapagosensis and O. deroyi were studied by Van Mol (1967).
Cohen and Nielsen (1978) placed this species in the genus Ogilbia. This species is probably evolved from the very similar Ogilbia deroyi (Poll and Van Moll 1966, DeRoy 1974). Individuals of O. galapagosensis vary considerably in colour, from brown through to pink, and also in eye size and body shape. D.M. Cohen (in Grove and Lavenberg 1997:224) has suggested that the different morphs may be separate species. Van Mol (1967) made a comparative anatomical study of O. galapagosensis and O. deroyi.
Morphological and molecular studies by Moller et al. (2016) showed that thew genus Ogilbia is sister to Ogilbichthys and both are sister to the subterranean fish Typhlias pearsei. Ogilbia and Ogilbichthys diverged 20 million years ago and both diverged from the monotypic Typhlias 30 million years ago. These studies also showed that Ogilbia galapagosensis is a member of the tribe Dinematichthyini together with two other subterranean species Typhlias pearsei and Diancistrus typhlops. They also raised the tribe to the level of Family, Dinematichthyidae Whitley 1928, and all three subterranean species are now placed in this Family and removed from Bythitidae.
(Nielsen, J.G., Munroe, T., Tyler, J. & Robertson, R. 2010. Ogilbia galapagosensis. The IUCN Red List of Threatened Species 2010. http://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T15184A4499879.en. Downloaded on 10 July 2017).
As above only.
- Poll, M. and Leleup, N. (1965)
- Poll, M. and Van Mol, J.J. (1966)
- Van Mol, J.J. (1967)
- Van Mol, J.J. (1967)
- Leleup, N. and Leleup, J. (1968)
- DeRoy, T. A. (1974)
- Suarez, S.S. (1975)
- Cohen, D. M. and Nielsen, J. G. (1978)
- Iliffe, T. M. (1991)
- Peck, S. B. and Finston, T. L. (1993)
- Peck, S. B. (1994)
- Peck, S. B. (1994)
- Snell, H.M, Stone, P.A. and Snell, H.L (1996)
- Grove, J. S. and Lavenberg, R. J. (1997)
- Nielsen, J. G., Cohen, D. M., Markle, D.F. and Robins, C. R. (1999)
- Moller, PR, Schwarzhans, W and Nielsen, JG (2005)
- Moller, PR, Knudsen, SW, Schwarzhans, W and Nielsen, JG (2016)
|Poll, M. and Leleup, N.||Journal Article||1965||Un poisson aveugle nouveau de la famille des Brotulidae provenant des iles Galapagos|
|Poll, M. and Van Mol, J.J.||Journal Article||1966||Au sujet d'une espece inconnue de Brotulidae littoral des iles Galapagos, apparentee a l'espece aveugle Caecogilbia galapagosensis Poll et Leleup|
|Van Mol, J.J.||Journal Article||1967||Ecologie comparee de deux especes de Brotulidae (Pisces) des iles Galapagos: Caecogilbia deroyi Poll et Van Mol 1967 et C. galapagosensis Poll et Leleup 1965|
|Van Mol, J.J.||Journal Article||1967||Etude anatomique du genre Caecogilbia Poll et Leleup|
|Leleup, N. and Leleup, J.||Journal Article||1968||Mission zoologique belge aux iles Galapagos et en Ecuador. Resultats scientifiques|
|DeRoy, T. A.||Journal Article||1974||Discovering a new species|
|Suarez, S.S.||Journal Article||1975||The reproductive biology of Ogilbia cayorum, a viviparous brotulid fish|
|Cohen, D. M. and Nielsen, J. G.||Journal Article||1978||Guide to the identification of genera of the fish order Ophidiiformes with a tentative classification of the order|
|Iliffe, T. M.||Book Section||1991||Anchialine fauna of the Galapagos Islands.|
|Peck, S. B. and Finston, T. L.||Journal Article||1993||Galapagos Island troglobites: The question of tropical troglobites, parapatric distribution with eyed sister species, and their origin by parapatric speciation|
|Peck, S. B.||Journal Article||1994||Diversity and zoogeography of the non-oceanic crustacea of the Galapagos Islands, Ecuador|
|Peck, S. B.||Book Section||1994||Ecuador|
|Snell, H.M, Stone, P.A. and Snell, H.L||Journal Article||1996||A summary of geographical characteristics of the Galapagos Islands|
|Grove, J. S. and Lavenberg, R. J.||Book||1997||The fishes of the Galapagos Islands|
|Nielsen, J. G., Cohen, D. M., Markle, D.F. and Robins, C. R.||Journal Article||1999||Ophidiiform fishes of the world (Order Ophidiiformes). An annotated and illustrated catalogue of pearlfishes, cusk-eels, brotulas and other ophidiiform fishes known to date|
|Moller, PR, Schwarzhans, W and Nielsen, JG||Journal Article||2005||Review of the American Dinematichthyini (Teleostei: Bythitidae). Part II. Ogilbia|
|Moller, PR, Knudsen, SW, Schwarzhans, W and Nielsen, JG||Journal Article||2016||A new classification of viviparous brotulas (Bythitidae) – with family status for Dinematichthyidae – based on molecular, morphological and fossil data| | <urn:uuid:0d4c8537-a538-488e-b750-9b15113f96c1> | 2.609375 | 1,989 | Knowledge Article | Science & Tech. | 69.249569 | 95,515,062 |
Threading Building Blocks
Threading Building Blocks TBB is a C++ template library developed by Intel for parallel programming on multi-core processors Using TBB, a computation is broken down into tasks that can run in parallel The library manages and schedules threads to execute these tasks
- 1 Overview
- 2 Library contents
- 3 Systems supported
- 4 See also
- 5 Notes
- 6 References
- 7 External links
A TBB program creates, synchronizes and destroys graphs of dependent tasks according to algorithms, ie high-level parallel programming paradigms aka Algorithmic Skeletons Tasks are then executed respecting graph dependencies This approach groups TBB in a family of solutions for parallel programming aiming to decouple the programming from the particulars of the underlying machine
TBB implements work stealing to balance a parallel workload across available processing cores in order to increase core utilization and therefore scaling Initially, the workload is evenly divided among the available processor cores If one core completes its work while other cores still have a significant amount of work in their queue, TBB reassigns some of the work from one of the busy cores to the idle core This dynamic capability decouples the programmer from the machine, allowing applications written using the library to scale to utilize the available processing cores with no changes to the source code or the executable program file In a 2008 assessment of the work stealing implementation in TBB, researchers from Princeton University found that it was suboptimal for large numbers of processors cores, causing up to 47% of computing time spent in scheduling overhead when running certain benchmarks on a 32-core system4
TBB, like the STL and the part of the C++ standard library based on it, uses templates extensively This has the advantage of low-overhead polymorphism, since templates are a compile-time construct which modern C++ compilers can largely optimize away
Intel TBB is available commercially as a binary distribution with support,5 and as open-source software in both source and binary forms6
TBB does not provide guarantees of determinism or freedom from data races7
TBB is a collection of components for parallel programming:
- Basic algorithms: parallel_for, parallel_reduce, parallel_scan
- Advanced algorithms: parallel_while, parallel_do, parallel_pipeline, parallel_sort
- Containers: concurrent_queue, concurrent_priority_queue, concurrent_vector, concurrent_hash_map
- Memory allocation: scalable_malloc, scalable_free, scalable_realloc, scalable_calloc, scalable_allocator, cache_aligned_allocator
- Mutual exclusion: mutex, spin_mutex, queuing_mutex, spin_rw_mutex, queuing_rw_mutex, recursive_mutex
- Atomic operations: fetch_and_add, fetch_and_increment, fetch_and_decrement, compare_and_swap, fetch_and_store
- Timing: portable fine grained global time stamp
- Task scheduler: direct access to control the creation and activation of tasks
The TBB commercial release 30 supports Windows XP or newer, OS X version 1058 or higher and Linux using Visual C++ version 80 or higher, on Windows only, Intel C++ Compiler version 111 or higher or the GNU Compiler Collection gcc8 Additionally, the TBB open source community has contributed patches for Solaris,9 PowerPC, Xbox 360, QNX Neutrino, and FreeBSD
- Cilk/Cilk Plus
- Intel Parallel Studio XE
- Intel Integrated Performance Primitives IPP
- Intel Data Analytics Acceleration Library DAAL
- Intel Math Kernel Library MKL
- Intel Parallel Advisor
- Intel Parallel Inspector
- Intel VTune Amplifier
- Intel Concurrent Collections CnC
- Algorithmic skeleton
- Parallel computing
- List of C++ multi-threading libraries
- List of C++ template libraries
- Parallel Patterns Library
- Grand Central Dispatch GCD
- ^ "What's New Intel® Threading Building Blocks 2017"
- ^ "Intel Threading Building Blocks Release Notes"
- ^ "No Cost Options for Intel Parallel Studio XE, Support yourself, Royalty-Free"
- ^ Contreras, Gilberto; Martonosi, Margaret 2008 Characterizing and improving the performance of Intel Threading Building Blocks PDF IEEE Int'l Symp on Workload Characterization
- ^ http://wwwthreadingbuildingblockscom Intel Threading Building Blocks Commercial Version Homepage
- ^ http://wwwthreadingbuildingblocksorg Threading Building Blocks Open Source Project Homepage
- ^ Bocchino Jr, Robert L; Adve, Vikram S; Adve, Sarita V; Snir, Marc 2009 Parallel Programming Must Be Deterministic by Default USENIX Workshop on Hot Topics in Parallelism
- ^ "Intel Threading Building Blocks - Release Notes Version 30" Retrieved 2011-08-08
- ^ "Using Intel's Threaded Building Blocks TBB With Sun Studio Express" Retrieved 2008-05-08
- Reinders, James July 2007, Intel Threading Building Blocks: Outfitting C++ for Multi-core Processor Parallelism Paperback ed, Sebastopol: O'Reilly Media, ISBN 978-0-596-51480-8
- Voss, M October 2006, Demystify Scalable Parallelism with Intel Threading Building Blocks' Generic Parallel Algorithms
- Voss, M December 2006, Enable Safe, Scalable Parallelism with Intel Threading Building Blocks' Concurrent Containers
- Hudson, Richard L; Saha, Bratin; Adl-Tabatabai, Ali-Reza; Hertzberg, Benjamin C 2006, "McRT-Malloc", Proceedings of the 2006 international symposium on Memory management - ISMM '06, pp 74–83, doi:101145/11339561133967, ISBN 1595932216
- Official website
- tbb on GitHub
- Official website at Intel
|Items in italics are no longer maintained or have planned end-of-life dates|
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Massive galaxies in the Universe have stopped making their own stars and are instead snacking on nearby galaxies, according to research by Australian scientists.
Astronomers looked at more than 22,000 galaxies and found that while smaller galaxies were very efficient at creating stars from gas, the most massive galaxies were much less efficient at star formation, producing hardly any new stars themselves, and instead grew by eating other galaxies.
The study was released today in the journal Monthly Notices of the Royal Astronomical Society, published by Oxford University Press.
Dr Aaron Robotham based at The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), said smaller ‘dwarf’ galaxies were being eaten by their larger counterparts.
“All galaxies start off small and grow by collecting gas and quite efficiently turning it into stars,” he said.
“Then every now and then they get completely cannibalised by some much larger galaxy.”
Dr Robotham, who led the research, said our own Milky Way was at a tipping point and expected to now grow mainly by eating smaller galaxies, rather than by collecting gas.
“The Milky Way hasn’t merged with another large galaxy for a long time but you can still see remnants of all the old galaxies we’ve cannibalised,” he said.
“We’re also going to eat two nearby dwarf galaxies, the Large and Small Magellanic Clouds, in about four billion years.”But Dr Robotham said the Milky Way would eventually get its comeuppance when it merged with the nearby Andromeda Galaxy in about five billion years.
“Technically, Andromeda will eat us because it’s the more massive one,” he said.
Almost all of the data for the research was collected with the Anglo-Australian Telescope in New South Wales as part of the Galaxy And Mass Assembly (GAMA) survey, led by Professor Simon Driver at ICRAR.
The GAMA survey involves more than 90 scientists and took seven years to complete.
This study is one of more than 60 publications to have come from the work, with another 180 in progress.
Dr Robotham said as galaxies grew they had more gravity and could therefore more easily pull in their neighbours.
He said the reason star formation slowed down in really massive galaxies was thought to be because of extreme feedback events in a very bright region at the centre of a galaxy known as an active galactic nucleus.
“The topic is much debated, but a popular mechanism is where the active galactic nucleus basically cooks the gas and prevents it from cooling down to form stars,” Dr Robotham said.
Ultimately, gravity is expected to cause all the galaxies in bound groups and clusters to merge into a few super-giant galaxies, although we will have to wait many billions of years before that happens.
“If you waited a really, really, really long time that would eventually happen but by really long I mean many times the age of the Universe so far,” Dr Robotham said.
ICRAR is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia.
‘Galaxy and Mass Assembly (GAMA): Galaxy close-pairs, mergers and the future fate of stellar mass’ in the Monthly Notices of the Royal Astronomical Society. Published online 19/9/2014 at: http://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stu1604
Preprint version accessible at: http://arxiv.org/abs/1408.1476
Dr Aaron Robotham
ICRAR – UWA (Currently travelling in South Africa, GMT +2:00)
Professor Simon Driver
Principal Investigator of the GAMA project. ICRAR – UWA (Perth, GMT +8:00)
Ph: +61 8 6488 7747 M: +61 400 713 514 E: firstname.lastname@example.org
Media Contact, ICRAR (Perth, GMT +8:00)
Ph: +61 8 6488 7771 M: +61 438 361 876 E: email@example.com
UWA Media Office
Ph: +61 8 6488 7977
Kirsten Gottschalk | Eurek Alert!
Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters
Theorists publish highest-precision prediction of muon magnetic anomaly
16.07.2018 | DOE/Brookhaven National Laboratory
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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- SEE ALSO
Math::Random::OO - Consistent object-oriented interface for generating random numbers
# Using factory functions use Math::Random::OO qw( Uniform UniformInt ); push @prngs, Uniform(), UniformInt(1,6); # Explicit creation of subclasses use Math::Random::OO::Normal; push @prngs, Math::Random::OO::Normal->new(0,2); $_->seed(23) for (@prngs); print( $_->next(), "\n") for (@prngs);
CPAN contains many modules for generating random numbers in various ways and from various probability distributions using pseudo-random number generation algorithms or other entropy sources. (The "SEE ALSO" section has some examples.) Unfortunately, no standard interface exists across these modules. This module defines an abstract interface for random number generation. Subclasses of this model will implement specific types of random number generators or will wrap existing random number generators.
This consistency will come at the cost of some efficiency, but will enable generic routines to be written that can manipulate any provided random number generator that adheres to the interface. E.g., a stochastic simulation could take a number of user-supplied parameters, each of which is a Math::Random::OO subclass object and which represent a stochastic variable with a particular probability distribution.
use Math::Random::OO qw( Uniform UniformInt Normal Bootstrap ); $uniform = Uniform(-1,1); $uni_int = UniformInt(1,6); $normal = Normal(1,1); $boot = Bootstrap( 2, 3, 3, 4, 4, 4, 5, 5, 5 );
In addition to defining the abstract interface for subclasses, this module imports subclasses and exports factory functions upon request to simplify creating many random number generators at once without typing
Math::Random::OO::Subclass->new() each time. The factory function names are the same as the suffix of the subclass following
Math::Random::OO. When called, they pass their arguments directly to the
new constructor method of the corresponding subclass and return a new object of the subclass type. Supported functions and their subclasses include:
Uniform-- Math::Random::OO::Uniform (uniform distribution over a range)
UniformInt-- Math::Random::OO::UniformInt (uniform distribution of integers over a range)
Normal-- Math::Random::OO::Normal (normal distribution with specified mean and standard deviation)
Bootstrap-- Math::Random::OO::Bootstrap (bootstrap resampling from a non-parameteric distribution)
All Math::Random::OO subclasses must follow a standard interface. They must provide a
new method, a
seed method, and a
next method. Specific details are left to each interface.
This is the standard constructor. Each subclass will define parameters specific to the subclass.
$prng->seed( @seeds );
This method takes seed (or list of seeds) and uses it to set the initial state of the random number generator. As some subclasses may optionally use/require a list of seeds, the interface mandates that a list must be acceptable. Generators requiring a single seed must use the first value in the list.
As seeds may be passed to the built-in
srand() function, they may be truncated as integers, so 0.12 and 0.34 would be the same seed.
$rnd = $prng->next();
This method returns the next random number from the random number generator. It does not take (and must not use) any parameters.
Please report bugs using the CPAN Request Tracker at http://rt.cpan.org/NoAuth/Bugs.html?Dist=Math-Random-OO
David A Golden <email@example.com>
Copyright (c) 2004, 2005 by David A. Golden
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file included with this module.
This is not an exhaustive list -- search CPAN for that -- but represents some of the more common or established random number generators that I've come across.
- Math::Random -- multiple random number generators for different distributions (a port of the C randlib)
- Math::Rand48 -- perl bindings for the drand48 library (according to perl56delta, this may already be the default after perl 5.005_52 if available)
- Math::Random::MT -- The Mersenne Twister PRNG (good and fast)
- Math::TrulyRandom -- an interface to random numbers from interrupt timing discrepancies | <urn:uuid:c84ac701-2c72-48cd-a58d-58a10f3013d0> | 2.71875 | 998 | Documentation | Software Dev. | 42.959108 | 95,515,093 |