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Microscopic particles that bind under low temperatures will melt as temperatures rise to moderate levels, but re-connect under hotter conditions, a team of New York University scientists has found. Their discovery points to new ways to create “smart materials,” cutting-edge materials that adapt to their environment by taking new forms, and to sharpen the detail of 3D printing.
“These findings show the potential to engineer the properties of materials using not only temperature, but also by employing a range of methods to manipulate the smallest of particles,” explains Lang Feng, the study’s lead author and an NYU doctoral student at the time it was conducted.
Image courtesy of Lang Feng.
Microscopic particles that bind under low temperatures (blue: bottom left) will melt as temperatures rise to moderate levels (green: center), but re-connect under hotter conditions (red: top right), a team of NYU scientists has found. Their discovery points to new ways to create “smart materials,” cutting-edge materials that adapt to their environment by taking new forms, and to sharpen the detail of 3D printing.
The research, which appears in the journal Nature Materials, reveals that the well-known Goldilocks Principle, which posits that success is found in the middle rather than at extremes, doesn’t necessarily apply to the smallest of particles.
The study focuses on polymers and colloids—particles as small as one-billionth and one-millionth of a meter in size, respectively.
These materials, and how they form, are of notable interest to scientists because they are the basis for an array of consumer products. For instance, colloidal dispersions comprise such everyday items as paint, milk, gelatin, glass, and porcelain and for advanced engineering such as steering light in photonics.
By better understanding polymer and colloidal formation, scientists have the potential to harness these particles and create new and enhanced materials—possibilities that are now largely untapped or are in relatively rudimentary form.
In the Nature Materials study, the researchers examined polymers and larger colloidal crystals at temperatures ranging from room temperature to 85 degrees C.
At room temperature, the polymers act as a gas bumping against the larger particles and applying a pressure that forces them together once the distance between the particles is too small to admit a polymer. In fact, the colloids form a crystal using this process known as the depletion interaction—an attractive entropic force, which is a dynamic that results from maximizing the random motion of the polymers and the range of space they have the freedom to explore.
As usual, the crystals melt on heating, but, unexpectedly, on heating further they re-solidify. The new solid is a Jello-like substance, with the polymers adhering to the colloids and gluing them together. This solid is much softer, more pliable and more open than the crystal.
This result, the researchers observe, reflects enthalpic attraction—the adhesive energy generated by the higher temperatures and stimulating bonding between the particles. By contrast, at the mid-level temperatures, conditions were too warm to accommodate entropic force, yet too cool to bring about enthalpic attraction.
Lang, now a senior researcher at ExxonMobil, observes that the finding may have potential in 3D printing. Currently, this technology can create 3D structures from two-dimensional layers. However, the resulting structures are relatively rudimentary in nature. By enhancing how particles are manipulated at the microscopic level, these machines could begin creating objects that are more detailed, and realistic, than is currently possible.
This work is supported partially by the National Science Foundation’s MRSEC Program (DMR-0820341), NASA (NNX08AK04G), and the Department of Energy (DE-SC0007991).
Deputy Director for Media Relations
James Devitt | newswise
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:43c6f694-7c17-4dae-860d-3ba242166004> | 3.578125 | 1,383 | Content Listing | Science & Tech. | 34.512885 | 95,621,211 |
Researchers at the University of Edinburgh have shown that the hormone vasopressin helps the brain differentiate between familiar and new scents.
The study, published in the journal Nature, suggests that when the hormone fails to function, animals are unable to recognise other individuals from their scent.
The ability to recognise others by smell is crucial in helping animals to establish strong bonds with other animals.
The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), may offer clues about the way people make emotional connections with others through smell and deepen our understanding of the role scent plays in memory.
Many scientists think a failure in this recognition system in humans may prevent them from forming deep emotional bonds with others.
It is thought that it may be at the root of conditions such as some forms of autism and social phobia.
Researchers, including scientists in Germany and Japan, reached their conclusion by studying the way rats familiarise themselves with other rats through smell.
They placed an adult rat in an enclosure with a baby rat and left them to sniff and interact with each other.
After a short separation, they placed the baby back in the adult's enclosure, together with an unknown baby.
Adult rats whose vasopressin had been blocked failed to recognise the baby they had already met.
Professor Mike Ludwig, who led the study at the University of Edinburgh, said: "This study gives us a window into understanding the biological basis of social interactions.
It may be that vasopressin helps to filter sensory information according to its emotional significance."
Professor Janet Allen, BBSRC Director of Research said, "Research that helps us to gain a fundamental understanding of how our brains work is vital if we are to know what is happening when something has gone wrong. The biological basis of psychological responses can often be extremely complicated, so finding this direct relationship between a hormone and a psycho-social phenomenon could open up a whole wealth of knowledge in this area."
Tara Womersley | EurekAlert!
Colorectal cancer risk factors decrypted
13.07.2018 | Max-Planck-Institut für Stoffwechselforschung
Algae Have Land Genes
13.07.2018 | Julius-Maximilians-Universität Würzburg
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
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences | <urn:uuid:b3042fd2-e25f-41c1-baf1-e745d6aa23b8> | 3.453125 | 1,051 | Content Listing | Science & Tech. | 39.72478 | 95,621,218 |
In the following example, the list object assigned to the name L is referenced both from L and from inside the list assigned to the name M.
Changing L in place changes what M references, too:
L = [1, 2, 3] M = ['X', L, 'Y'] # Embed a reference to L print( M ) L = 0 # Changes M too print( M )
You can avoid sharing objects by copying them explicitly.
For lists, you can always make a top-level copy by using an empty-limits slice:
L = [1, 2, 3] M = ['X', L[:], 'Y'] # Embed a copy of L (or list(L), or L.copy()) L = 0 # Changes only L, not M print( L ) print( M )# from w w w .j a v a 2 s .c o m
Slice limits default to 0 and the length of the sequence being sliced.
If both are omitted, the slice extracts every item in the sequence and so makes a top-level copy a new unshared object. | <urn:uuid:0cb6de4c-8bb9-46f1-8d06-4eb486818947> | 3.4375 | 233 | Documentation | Software Dev. | 85.689444 | 95,621,225 |
Ecology and Conservation of Forest Birds is a unique review of current understanding of the relationships between forest birds and their changing environments. Large ecological changes are being driven by forest management, climate change, introduced pests and pathogens, abiotic disturbances, and overbrowsing. Many forest bird species have suffered population declines, with the situation being particularly severe for birds dependent on attributes such as dead wood, old trees and structurally complex forests. With a focus on the non-tropical parts of the Northern Hemisphere, the text addresses the fundamental evolutionary and ecological aspects of forest birds using original data analyses and synthesising reviews. The characteristics of bird assemblages and their habitats in different European forest types are explored, together with the macroecological patterns of bird diversity and conservation issues. The book provides a valuable reference for ecologists, ornithologists, conservation professionals, forest industry employees, and those interested in birds and nature.
1. Introduction Grzegorz Mikusinski, Jean-Michel Roberge and Robert J. Fuller; Part I. Forest Birds and their Adaptations: 2. Origins and dynamics of forest birds of the Northern Hemisphere Jacques Blondel; 3. Ecological adaptations of birds to forest environments Marc-Andre Villard and Ruud Foppen; 4. Tree holes and hole-nesting birds in European and North American forests Tomasz Wesolowski and Kathy Martin; Part II. European Forests and their Bird Communities: 5. Macroecological patterns in forest bird diversity in Europe Grzegorz Mikusinski, Dani Villero, Sergi Herrando and Lluis Brotons; 6. Boreal forest bird assemblages and their conservation Jean-Michel Roberge, Raimo Virkkala and Mikko Moenkkoenen; 7. Subalpine coniferous forests of Europe: Avian communities in European high altitude woodlands Pierre Mollet, Kurt Bollmann, Veronika Braunisch and Raphael Arlettaz; 8. Temperate forests: a European perspective on variation and dynamics in bird assemblages Tomasz Wesolowski, Robert J. Fuller and Martin Flade; 9. Mediterranean forest bird communities and the role of landscape heterogeneity in space and time Lluis Brotons, Sergi Herrando, Clelia Sirami, Vassiliki Kati and Mario Diaz; 10. Plantations of non-native tree species: opportunities and limitations for birds in intensively managed forests John Calladine, Mario Diaz, Luis Reino, David Jardine and Mark Wilson; Part III. Conservation and Management: 11. Population trends and conservation status of forest birds Aleksi Lehikoinen and Raimo Virkkala; 12. Hunting and other forms of exploitation and persecution of forest birds Ilse Storch; 13. Conservation strategies and habitat management for European forest birds Robert J. Fuller and Hugo Robles; 14. Future forests, avian implications and research priorities Grzegorz Mikusinski, Jean-Michel Roberge and Robert J. Fuller; Index. | <urn:uuid:4ca3585f-48c4-4bb1-adf1-5c5b03e10a93> | 3.15625 | 627 | Product Page | Science & Tech. | 17.446808 | 95,621,249 |
New research intended to dissect one of the planet’s most fertile and endangered ecosystems may change the way scientists look at this symbiotic partnership, shifting it from a case where the polyps function only as landlords to one where the tiny creatures actually nurture their algae.
Preliminary findings were presented today in two papers at the 2008 Ocean Sciences meeting in Orlando. The research focuses on the key role that carbon plays on the recovery of damaged coral reefs.
Andrea Grottoli, an assistant professor of earth sciences at Ohio State University, has spent the last 14 years studying two common forms of coral that populate the reefs near the Hawaii Institute of Marine Biology.
Two years ago, she reported that one of the corals she tested, Montipora capitata, or “rice” coral, was able to recover rapidly from bleaching because it increased its rate of feeding five-fold compared to how fast another form, Porites compressa, or “finger” coral, fed.
This strategy of gluttony enabled Montipora to survive the long-term damage that corals suffer when sea temperature climbs beyond the narrow 4 – 6 degree C range, where Porites might not.
What wasn’t clear from the earlier experiments was how the corals actually made use of carbon for their survival.
But when seawater temperatures climb, the coral will either jettison the algae altogether, or the algal cells will lose the pigments essential for photosynthesis to deliver the needed carbon. Without the algae, corals appear white, which is often referred to as “bleached.” Prolonged bleaching can lead to the coral dying. Either case presents a serious threat to the tiny creatures.
Grottoli wanted to determine exactly how the coral obtained its carbon and, in turn, how it used the material to survive. She placed samples of both healthy and bleached corals of both types in tanks mimicking actual ocean conditions. In one set of experiments, she pumped in seawater containing higher-than-normal levels of a carbon isotope, C-13. In another, she fed the corals zooplankton that were also heavily laced with the carbon isotope.
“We could track the carbon and determine if it was coming from either the photosynthetic process or from the animals’ feeding,” she said, “and then see how it was ultimately used by the animals. We could tell whether the process differed if the corals were healthy or bleached, or one species or the other.”
The experiments readily showed, as expected, that healthy corals had much more of the seawater-labeled carbon than did bleached corals, she said.
“But we could also see that in the healthy coral, the carbon was transferred into the algae where it is used for photosynthesis, and ultimately ends up in the animals’ skeleton,” Grottoli said. “So the corals are using photosynthetic carbon for calcification and to meet their daily metabolic demands.”
The carbon consumed while feeding, however, isn’t ending up in the skeleton, she said. Instead, it’s ending up both in the tissue of the coral polyp or inside the algae. With bleached samples, the coral is apparently feeding carbon to the algae.
“That’s what our work suggests and this is new. We’ve known that nutrients like nitrogen and phosphorus are exchanged in this way but nobody ever knew that this was happening with carbon,” she said.
The bottom line, Grottoli says, is that the photosynthetic carbon is used for metabolic demands and calcification, while the carbon gained from feeding is used for tissue growth.
“Without both forms, the coral simply cannot fully recover,” she said.
“All corals need both photosynthesis and feeding for recovery and the rate of those two processes is the key to whether the coral can actually meet all its metabolic demands and ultimately recover.”
Grottoli’s work is supported in part by the National Science Foundation. Along with Grottoli, Adam Hughes, a postdoctoral fellow in her lab, and Tamara Pease, an assistant professor of marine science at the University of Texas at Austin, worked on the project.
Andrea Grottoli | 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...
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:a2d7cc74-7075-4435-8a96-134255df84d1> | 4.125 | 1,568 | Content Listing | Science & Tech. | 41.645537 | 95,621,258 |
Canadian Arthur McDonald, who shared the Nobel Physics Prize with Takaaki Kajita of Japan, said Tuesday he hoped their work on neutrinos could pave the way to nuclear fusion power.
Neutrinos are subatomic particles created as the result of nuclear reactions, such as the process that makes the Sun shine.
The prevailing theory was long that neutrinos had no mass, but work carried out separately in underground labs by teams led by Kajita in Japan and McDonald in Canada showed that this was not the case.
Speaking on Canada’s public broadcaster CBC, McDonald said his work on the particles could be used for “measuring the fusion reactions that power the Sun.”
“Knowing that the calculations that are applicable to the Sun are correct helps a lot when you’re trying to understand what’s being done here on Earth,” he explained.
In contrast to nuclear fission, nuclear fusion holds out promise of a cheap, plentiful and safe form of power.
Understanding how fusion works in the Sun would help efforts to replicate the process — on an infinitely smaller scale — on Earth.
At age 72, Arthur McDonald said winning the Nobel Prize brought him back many years.
“We started in 1984 with 16 people, and we went on to work at this for many years with tremendous support from Canada to do something really unusual here,” he recalled.
“It turned out to be a great success that we’re very proud of.”
When McDonald received the call at 5 am local time (0900 GMT) informing him he had won the Nobel Prize, he said he knew right away it wasn’t a prank because he recognized the caller’s Swedish accent.
Receiving such an honor, he said, is “pretty unusual, but a great tribute to the hard work of all our team over many years.”
“And it’s wonderful to have that happen in Canada and for us to have been able to give many students (who worked at his Snolab) a real moment in the process,” he said.
McDonald has retired from teaching, but is still involved in research.
His original underground lab — located two kilometers below the surface in an old mine near Sudbury, Ontario where he experimented with neutrinos — has tripled in size and is now experimenting with dark matter particles.
“And that may lead to another (eureka) moment, we hope, before very long,” he said. | <urn:uuid:3610c0ce-0950-4d32-b1b2-0077697f48c0> | 3.546875 | 530 | News Article | Science & Tech. | 50.276821 | 95,621,260 |
Earthquakes come and go as they please, leaving behind them trails of destruc- tion and casualties. Although their occurrence is little affected by what we do or think, it is the task of earth scientists to keep studying them from all possible angles until ways and means are found to divert, forecast, and eventually control them. In ancient times people were awestruck by singular geophysical events, which were attributed to supernatural powers. It was recognized only in 1760 that earthquakes originated within the earth. A hundred years later, first systematic attempts were made to apply physical principles to study them. During the next century scientists accumulated knowledge about the effects of earthquakes, their geographic patterns, the waves emitted by them, and the internal constitution of the earth. During the past 20 years, seismology has made a tremendous progress, mainly because of the advent of modern computers and improvements in data acquisi- tion systems, which are now capable of digital and analog recording of ground motion over a frequency range of five orders of magnitude. These technologic developments have enabled seismologists to make measurements with far greater precision and sophistication than was previously possible. Advanced computational analyses have been applied to high-quality data and elaborate theoretical models have been devised to interpret them. As a result, far- reaching advances in our knowledge of the earth's structure and the nature of earthquake sources have occurred.
Publisher: Springer-Verlag New York Inc.
Number of pages: 1129
Weight: 1725 g
Edition: 1981 ed.
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posted by Aidan
if 4.35 kj of energy are needed to heat a sample of water from 62C into steam at 100.0C what is the mass of the sample
q1 - heat needed to go from 62 C to 100 C.
q1 = mass H2O x specific heat H2O x (Tfinal-Tinitial). Tf is 100 and Ti is 62.
q2 is heat needed to convert the sample of water at 100 to steam at 100.
q2 = mass H2O x heat vaporization.
So q1 + q2 = 4350 J
I show q1 above and q2 above. Set up the equation, mass H2O is the unknown you're looking for. You will need to look up specific heat H2O and heat vaporization if you don't already know it. Remember to keep the units straight; i.e., I've changer the 4.35 kJ to J. I suggest you keep everything in J. Post your work if you get stuck. | <urn:uuid:a2453582-bb98-4bb4-8859-432fdf694e25> | 2.578125 | 218 | Q&A Forum | Science & Tech. | 104.746442 | 95,621,294 |
BILLINGS, Mont. — U.S. officials said Wednesday they’ll review the recent lifting of protections for Yellowstone-area grizzly bears in light of a court ruling that retained protections for grey wolves in the Great Lakes.
You are here
TOKYO — Two types of New Zealand kiwi birds are a rare bright spot in a mostly grim assessment of global species at risk of extinction.
The International Union for the Conservation of Nature upgraded the Okarito kiwi and the Northern Brown kiwi from endangered to vulnerable thanks to New Zealand’s progress in controlling predators like stoats and cats.
WASHINGTON — Scientists are expanding the genetic code of life, using man-made DNA to create a semi-synthetic strain of bacteria ‚Äî and new research shows those altered microbes actually worked to produce proteins unlike those found in nature.
It’s a step toward designer drug development.
FLAGSTAFF, Ariz. — An effort to bring one of the world’s largest birds back from the brink of extinction is expanding after northern Arizona and southern Utah found some success in getting deer hunters to use ammunition not made of lead.
RENO, Nev. — More than 500 black bears have returned to parts of their historic range in the Great Basin of Nevada where the species disappeared about 80 years ago, scientists say.
A new study says genetic testing confirms the bears are making their way east from the Sierra ranges north and south of Lake Tahoe along the California line.
PORTLAND, Ore. — Wolves were once so plentiful in the abundant forests that would become Oregon that the earliest settlers gathered from far and wide to discuss how to kill them.
Those “wolf meetings” in the 1840s, spawned by a common interest, eventually led to the formation of the Oregon territory, the precursor for statehood in 1859.
CAPE CANAVERAL, Fla. — A new study suggests that dark streaks on Mars represent flowing sand ‚Äî not water.
WASHINGTON — Summer thunderstorms in North America will likely be larger, wetter and more frequent in a warmer world, dumping 80 per cent more rain in some areas and worsening flooding, a new study says.
Future storms will also be wilder, soaking entire cities and huge portions of states, according to a federally-funded study released Monday in the journal Nature Climate Change.
SEATTLE — Harbour seals, sea lions and some fish-eating killer whales have been rebounding along the Northeast Pacific Ocean in recent decades. But that boom has come with a trade-off: They’re devouring more of the salmon prized by a unique but fragile population of endangered orcas.
CAPE CANAVERAL, Fla. — A newly discovered object from another star system that’s passing through ours is shaped like a giant pink fire extinguisher.
That’s the word this week from astronomers who have been observing this first-ever confirmed interstellar visitor. | <urn:uuid:5176a736-4319-445c-8844-c01a9300ea66> | 2.546875 | 615 | Content Listing | Science & Tech. | 45.095839 | 95,621,300 |
Comprises a capillary tube, which is sealed at the bottom, having a graduated scale from 0 to 200mm. This is mounted onto a metal former which also has a -10 _ 100°C thermometer mounted alongside the tube. The overall length is 350mm with a hole at the top to affix to a retort stand to suspend the apparatus in a tall form beaker of water (not supplied). By heating the water and taking a temperature and scale reading every 30 seconds, a graph of the results can be plotted.
Through a line of best fit and extrapolation absolute zero can be demonstrated. The straight line supports Charles′ Law demonstrating that volume of a gas is directly proportional to its temperature provided the pressure is kept constant. (In this case the pressure is atmospheric pressure). The Kelvin scale may then be introduced. | <urn:uuid:77d0b936-a639-4df2-b15c-3ca7a52a0946> | 3.265625 | 168 | Knowledge Article | Science & Tech. | 50.599032 | 95,621,307 |
The most ambitious genetic study ever undertaken on bird evolution has found that almost all modern birds diversified after the dinosaurs became extinct 66 million years ago.
"The popular view until now has been that the extraordinary diversity of birds began during the dinosaur age but we found little support for this," said Associate Professor Simon Ho, from the University of Sydney who led a major component of the research looking at evolutionary timescale.
An international collaboration of scientists worked for four years to sequence, assemble and compare the full genomes of 48 bird species representing all major branches of modern birds. It is the largest whole genomic study across a single vertebrate class ever undertaken.
Their results appear in a special edition of Science on 12 December (with simultaneous publications of related articles in other high profile journals).
Associate Professor Ho, from the University's School of Biological Sciences, is an author on a Science paper and two articles in GigaScience. He contributed his expertise in using a technique known as 'molecular clock' analysis to estimate birds' evolutionary timescales, using genome data and fossil evidence.
His research helped confirm that some of the first lineages of modern birds appeared about 100 million years ago but that almost all of the modern groups of birds diversified in a small window of less than 10 million years, just after the dinosaurs were wiped out by an asteroid.
"Our team had to develop a range of new methods to handle the largest bird data set ever assembled. These required the equivalent of more than 400 years of computing power across nine supercomputers," said Associate Professor Ho.
"The team was able to work out the relationships among the major groups of modern birds, showing that our previous understanding of birds had been clouded by the appearance of similar traits and habits in distantly related groups.
"So while grebes and cormorants are both waterbirds with webbed feet that dive to catch their prey they are, despite these similarities, from completely distinct lineages."
Another significant finding is that the ancestor of most of the land birds we see today is probably an apex predator that gave rise to raptors, eagles, owls and falcons in rapid succession before leading to land birds such as songbirds and woodpeckers.
"With the demise of the dinosaurs, birds and mammals were able to become more diverse and to occupy all of the niches that had previously been dominated by dinosaurs," said Associate Professor Simon Ho.
"This was one of the most significant episodes in the history of life on earth and it is tremendously exciting that this major scientific international effort has made these advances in our understanding," said Associate Professor Simon Ho.
Professor Eddie Holmes from the University of Sydney's School of Biological Sciences and Associate Professor Jaime Gongora and his research team from the Faculty of Veterinary Science also contributed to the international project and are authors on papers in Science and accompanying journals.
Verity Leatherdale | 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
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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Very few naturally occurring things on earth are truly negative. In most cases, naturally occurring things and events are usually a mix of good and bad; while they are partly destructive, they also have some pretty positive impact on the living beings on earth. However, that is not very true about the destructive forces of nature. When a hurricane, tornado, tsunami, or earthquake strikes, or a volcano erupts, we have no choice but to run for cover and wait for it to pass. These forces of nature bring in their wake immense destruction and loss of lives and property. It is tough to see anything good in the whole incident. However, volcanoes are slightly different from the rest. Despite their incredibly destructive nature, they do confer a considerable amount of benefits on the population.
The disadvantages of volcanoes:
Let us, however, begin with the obvious- the destruction wrought by volcanic eruptions.
When a volcano erupts, it causes immense destruction and loss of life and property. A volcanic eruption of moderate proportions leads to a number of geological changes that wreak havoc on human and animal lives. To begin with, a volcanic eruption is accompanied by a great amount of ash and molten lava, which is extremely destructive to life, property, and the natural landscape around. Severe volcanic eruptions have been known to destroy entire towns and cities, thanks to the smoke, fires, and ash that envelop entire settlements.
A volcanic eruption is always accompanied by huge amounts of volcanic ash, which is often extremely thick and capable of enveloping the sky and pervading the air for days on end. A good example would be the eruption of the Icelandic volcanic eruption of Eyjafjallajökull in 2010, when the ash from the eruption hung over numerous cities for many days, severely disrupting air travel for the duration. Not only that, the incidence of such ash over causes immense damage to the breathable air quality, and in turn to all animal and human lives.
Volcanic eruptions are often accompanied with mudslides and molten lava flow that burns anyone who comes into contact with it. If thick enough, this is also capable of burying entire settlements, as was the case with the twin cities of Pompeii and Herculaneum in ancient times. This is also often accompanied by thick, toxic smoke that renders the air unbreathable for miles around, causing a great percentage of the population to suffocate to death.
The benefits of volcanoes:
All said and done, however, volcanic eruptions are not always singularly destructive. They often come with a great amount of good for the population.
The lava that is emitted from volcanic eruptions is very good for the soil. It makes the soil extremely fertile and aids in the growing of a huge number of crops. This explains why there are always considerable amount of settlements around very active volcanoes; since constant or regular volcanic eruptions make the soil very conducive to agriculture, it is easy to lead a livelihood around a volcanic site.
A volcanic site is also a great source of revenue for the government of a country. While watching a volcano on action while you are present around it is not a very pleasant experience, there is a certain thrill in being around an active or even dormant volcano and knowing that it may erupt at any time. Besides, the scenery around a volcano is always breathtaking; since the minerals and other nutrients mixed with volcanic lava makes the soil very fertile, it paves the way for some of the most diverse and lush natural flora growing in it. As a chain reaction, the flora also attracts considerable local fauna, which adds to the attraction for tourists. Besides, tourists also enjoy the steam vents, mud pools, hot springs, and bathing lakes that are usually found around an area with considerable volcanic activity.
Volcanoes are economized in more ways than one. Apart from tourism, they are also highly economic for the local population. The earth around a volcano is extremely hot, which makes the very potent sources for extracting geothermal energy. This kind of energy is used commercially for a variety of purposes.
A volcano is a terribly destructive force that is impossible to harness despite all the technological advancements made by mankind. Yet, while we have had to bow our heads to the sheer power of nature that is manifested by volcanic eruptions, we have done our best to harness the good that comes out of such immense destruction. After all, it is only a volcano that leaves something to appreciate in it wake.Labels:negative effects of volcano, The positive and negative impact of volcanoes, negative EFFECTS OF VOLCANOS, positive and negative effects of volcano eruptions, positive aspects of volcanoes, the negative and positive effect of volcanism, | <urn:uuid:0e5a0c4e-6dbe-42eb-a808-9a7b6753344a> | 3.5 | 958 | Personal Blog | Science & Tech. | 29.719404 | 95,621,345 |
Majorana fermions are particles that could potentially be used as information units for a quantum computer. An experiment by physicists at the Swiss Nanoscience Institute and the University of Basel’s Department of Physics has confirmed their theory that Majorana fermions can be generated and measured on a superconductor at the end of wires made from single iron atoms. The researchers also succeeded in observing the wave properties of Majoranas and, therefore, in making the interior of a Majorana visible for the first time. The results were published in the Nature journal npj Quantum Information.
Around 75 years ago, Italian physicist Ettore Majorana hypothesized the existence of exotic particles that are their own antiparticles. Since then, interest in these particles, known as Majorana fermions, has grown enormously given that they could play a role in creating a quantum computer.
Majoranas have already been described very well in theory. However, examining them and obtaining experimental evidence is difficult because they have to occur in pairs but are then usually bound to form one normal electron. Ingenious combinations and arrangements of various materials are therefore required to generate two Majoranas and keep them apart.
Collaboration between theory and practice
The group led by Professor Ernst Meyer has now used predictions and calculations by theoretical physicists Professor Jelena Klinovaja and Professor Daniel Loss (from the Swiss Nanoscience Institute and the University of Basel’s Department of Physics) to experimentally measure states that correspond to Majoranas.
On a superconductor, the researchers evaporated single iron atoms with spin that, due to the row structure of the lead atoms, arrange themselves into a minute wire comprising one row of single atoms. The wires reached an astounding length of up to 70 nanometers.
Single Majoranas on the ends
The researchers examined these mono-atomic chains with the aid of scanning tunneling microscopy and, for the first time, with an atomic force microscope as well. Using the images and measurements, they found clear indications of the existence of single Majorana fermions on the ends of the wires under certain conditions and from a specific wire length on.
Despite the distance between them, the two Majoranas on the ends of the wires are still connected. Together, they form a new state extended across the whole wire that can either be occupied (“1”) or not occupied (“0”) by an electron. This binary property can then serve as the basis for a quantum bit (Qubit) and means that Majoranas, which are also very robust against a number of environmental influences, are promising candidates for creating a future quantum computer.
Predicted wavefunction measured
The researchers from Basel have not only shown that single Majoranas can be generated and measured at the ends of an iron wire, they also performed the first experiment to show that Majoranas are extended quantum objects with an inner structure, as predicted by their theory colleagues. Over an area of several nanometers, the measurements showed the expected wavefunction with characteristic oscillations and twofold decay lengths, which have now been made visible for the first time.
Rémy Pawlak, Marcin Kisiel, Jelena Klinovaja, Tobias Meier, Shigeki Kawai, Thilo Glatzel, Daniel Loss, and Ernst Meyer
Probing atomic structure and Majorana wavefunctions in mono-atomic Fe chains on superconducting Pb surface
npj Quantum Information (2016), doi: 10.1038/npjqi.2016.35
Prof. Dr. Jelena Klinovaja, University of Basel, Department of Physics, tel +41 61 267 36 56, email: email@example.com
Prof. Dr. Daniel Loss, University of Basel, Department of Physics, tel +41 61 267 37 49, email: firstname.lastname@example.org
Prof. Dr. Ernst Meyer, Univeristy of Basel, Department of Physics, tel +41 61 267 37 24, email:email@example.com
Reto Caluori | Universität Basel
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
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"Dark energy is one of the great scientific mysteries of our time, so it isn't surprising that so many researchers question its existence. But now, according to a team of astronomers at the University of Portsmouth and LMU University Munich, led by Tommaso Giannantonio and Robert Crittenden, the scientists the likelihood of the existence of dark matter stands at 99.996 per cent.
Over a decade ago, astronomers observing the brightness of distant supernovae realised that the expansion of the Universe appeared to be accelerating. The acceleration is attributed to the repulsive force associated with dark energy now thought to make up 73 per cent of the content of the cosmos. The researchers who made this discovery received the Nobel Prize for Physics in 2011, but the existence of dark energy remains a topic of hot debate. Many other techniques have been used to confirm the reality of dark energy but they are either indirect probes of the accelerating Universe or susceptible to their own uncertainties.
Clear evidence for dark energy comes from the Integrated Sachs Wolfe effect named after Rainer Sachs and Arthur Wolfe. The Cosmic Microwave Background, the radiation of the residual heat of the Big Bang, is seen all over the sky. In 1967 Sachs and Wolfe proposed that light from this radiation would become slightly bluer as it passed through the gravitational fields of lumps of matter, an effect known as gravitational redshift.
In 1996, Robert Crittenden and Neil Turok, now at the Perimeter Institute in Canada, took this idea to the next level, suggesting that astronomers could look for these small changes in the energy of the light, or photons, by comparing the temperature of the radiation with maps of galaxies in the local Universe.
In the absence of dark energy, or a large curvature in the Universe, there would be no correspondence between these two maps (the distant cosmic microwave background and relatively closer distribution of galaxies), but the existence of dark energy would lead to the strange, counter-intuitive effect where the cosmic microwave background photons would gain energy as they travelled through large lumps of mass.
The Integrated Sachs Wolfe effect was first detected in 2003 and was immediately seen as corroborative evidence for dark energy, featuring in the 'Discovery of the year' in Science magazine. But the signal is weak as the expected correlation between maps is small and so some scientists suggested it was caused by other sources such as the dust in our galaxy.
Since the first Integrated Sachs Wolfe papers, several astronomers have questioned the original detections of the effect and thus called some of the strongest evidence yet for dark energy into question. In the new paper, the product of nearly two years of work, the team have re-examined all the arguments against the Integrated Sachs Wolfe detection as well as improving the maps used in the original work. In their painstaking analysis, they conclude that there is a 99.996 per cent chance that dark energy is responsible for the hotter parts of the cosmic microwave background maps (or the same level of significance as the recent discovery of the Higgs boson).
"This work also tells us about possible modifications to Einstein's theory of General Relativity", notes Tommaso Giannantonio, lead author of the present study. "The next generation of cosmic microwave background and galaxy surveys should provide the definitive measurement, either confirming general relativity, including dark energy, or even more intriguingly, demanding a completely new understanding of how gravity works."
For more information: The new work appears in "The significance of the integrated Sachs-Wolfe effect revisited", T. Ginnantonio, R. Crittenden, R. Nichol, A. Ross, Monthly Notices of the Royal Astronomical Society, in press. A preprint of the paper is available from arxiv.org/abs/1209.2125 Journal reference: Monthly Notices of the Royal Astronomical Society.
Berkeley Lab scientists are the leaders of BOSS, the Baryon Oscillation Spectroscopic Survey. They and their colleagues in the third Sloan Digital Sky Survey have developed the most precise measurements ever made of the era when dark energy turned on.
In the image at the top of the page, BOSS measures the three-dimensional clustering of galaxies at various redshifts, revealing their precise distance, the age of the universe at that redshift, and how fast the universe has expanded. The measurement uses a "standard ruler" based on the regular variations of the temperature of the cosmic microwave background (CMB), which reveal variations in the density of matter in the early universe that gave rise to the later clustering of galaxies and large-scale structure of the universe today. (Credit: Eric Huff, the SDSS-III team, and the South Pole Telescope team. Graphic by Zosia Rostomian)
The image belwo is a visual impression of the data used in the study. The relevant extra-galactic maps are represented as shells of increasing distance from Earth from left to right. The closest thing seen is our Milky Way galaxy, which is a potential source of noise for the analysis. After this are six shells containing maps of the millions of distant galaxies used in the study.
These maps are produced using different telescopes in different wavelengths and are colour-coded to show denser clumps of galaxies as red and under-dense regions as blue. There are holes in the maps due to data quality cuts. The last, largest shell shows the temperature of the cosmic microwave background from the WMAP satellite (red is hot, blue is cold), which is the most distant image of the Universe seen, some 46 billion light-years away. The team have detected (at 99.996% significance) very small correlations between these foreground maps (on the left) and the cosmic microwave background (on the right).
The Daily Galaxy via the Royal Astronomical Society
Image credits: Earth: NASA/BlueEarth; Milky Way: ESO/S. Brunier; CMB: NASA/WMAP. | <urn:uuid:a093dc63-f047-42bb-8c55-c14c226805ab> | 3.125 | 1,224 | News Article | Science & Tech. | 33.761039 | 95,621,360 |
A revolutionary X-ray analytical technique that enables researchers at a glance to identify structural similarities and differences between multiple proteins under a variety of conditions has been developed by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab). As a demonstration, the researchers used this technique to gain valuable new insight into a protein that is a prime target for cancer chemotherapy.
“Proteins and other biological macromolecules are moving machines whose power is often derived from how their structural conformations change in response to their environment,” says Greg Hura, a scientist with Berkeley Lab’s Physical Biosciences Division. “Knowing what makes a protein change has incredible value, much like knowing that stepping on a gas pedal makes the wheels of a car spin.”
Hura led the development of what is being called a structural comparison map for use with small angle X-ray scattering (SAXS), an imaging technique for obtaining structural information about proteins and protein complexes in solution. Cynthia McMurray, a biologist with Berkeley Lab’s Life Sciences Division, provided the cancer-relevant protein used to test the new SAXS structural comparison map.
Says McMurray, “In biology, the first step in correcting a problem, such as the formation of a cancerous lesion, is understanding the conditions under which the problem arose. With the SAXS structural comparison map, we can compare multiple protein structures en masse and quickly identify areas of interest.”
Hura is the lead author and McMurray one of two corresponding authors of a paper in the journal Nature Methods that describes this research. The paper is titled “Comprehensive objective maps of macromolecular conformations by quantitative SAXS analysis.” Also a corresponding author is John Tainer, who holds joint appointments with Berkeley Lab’s Life Sciences Division and the Scripps Research Institute. The other authors are Helen Budworth, Kevin Dyer, Robert Rambo and Michal Hammel.
In perhaps no other area of science does the maxim “function follows form” hold more true than for proteins and protein complexes. The structural conformations created by the folding, twisting and turning of a protein’s amino acid chain can allow or prevent the protein from doing what it’s supposed to do and this can mean the difference between a healthy and an unhealthy cell. A protein can assume multiple distinct conformational states as it undergoes various chemical processes such as phosphorylation, nucleotide or ligand binding, ATP hydrolysis or the formation of complexes.
The most widely used technique for determining a protein’s structure remains crystallography, but many proteins and protein complexes can’t be crystalized. Furthermore, though precise, crystallography is a low-throughput process that can only capture one conformational state at a time. Enter SAXS, a high-throughput technique that can image any protein or protein complex in solution under any condition, and provide nanoscale resolution for distinguishing and characterizing the different conformational states that flexible biological macromolecules such as proteins can assume.
“With SAXS, there are relatively few restraints on conditions, construction, concentration or solution chemistry,” Hura says. “However, analytical methods have not kept pace with the hardware. While there are many factors that may induce a protein to undergo structural changes, these factors are difficult to predict. Our structural comparison map technique gives us a high-throughput screening capability. The combination of SAXS and our maps allows us to highlight those factors that make the biggest difference in structural conformations. We’re also able to track trends and identify intermediate states and other factors that shift equilibrium from one structure to another.”
The data in a structural comparison map is presented in the form of a color-coded checkerboard with similarity scores displayed as gradients moving from red, indicating high, to white, indicating low, and various shades of orange and yellow in between.
“With structural comparison maps, I can immediately see which structures under which conditions are the same and which are not,” says McMurray. “The maps provide both structural and chemical information and enable us to identify those conformations we should be looking at.”
To test the structural conformation map technique, co-author Budworth, a member of McMurray’s research group, prepared samples of a protein known as MutSß, an inviting chemotherapeutic target because of its ability to remove problematic DNA that can lead to cancer and other genetic mutations.
“MutSß is a heterodimer whose two macromolecules undergo an ordered series of nucleotide-dependent steps to initiate DNA repair,” Budworth says. “Each discrete nucleotide-bound state is a conformational state decision point that primes the next pathway step. A mechanistic understanding of these steps is crucial to learning how cells avoid mutation.”
Says McMurray, “Initially this was a very big puzzle because MutSß had no crystal structure, nor could we take a look at any one conformational state and say this is good or this is bad. The structural conformation maps allowed us to characterize the different conformational states individually and then compare them to one another. We discovered that DNA has surprisingly little impact on MutSß conformational structures, a fact that was not evident from biochemical measurements, but obvious when examining the maps.”
From the SAXS imaging and structural conformation map analysis, McMurray and her group believe that DNA is sculpted to the protein conformation and that nucleotide-binding drives MutSß conformational changes. This, they say, holds implications for future cancer therapies.
The MutSß samples were subjected to SAXS at the SIBYLS beamline of Berkeley Lab’s Advanced Light Source, a synchrotron that generates premier beams of X-ray and ultraviolet light for scientific research. The acronym SIBYLS stands for Structurally Integrated Biology for Life Sciences. The beamline is maintained by Berkeley Lab’s Life Sciences Division under the direction of corresponding author Tainer.
Says Tainer, “The structural comparison map technique is a big step forward in the development of tools that will help biologists use the full potential of the awesome throughput we expect to achieve with the next generation of light sources.”
This research was supported by funds from the DOE Office of Science and from the National Institutes of Health.
DOE/Lawrence Berkeley National Laboratory | <urn:uuid:16d3aa92-842d-46cd-afef-89911adece8e> | 3.15625 | 1,367 | Academic Writing | Science & Tech. | 21.884118 | 95,621,364 |
For decades, researchers have been looking at how different-sized legs and feet are put together across the four-legged animal kingdom, but until now they overlooked the "shoes," those soft pads on the bottom of the foot that bear the brunt of the animal's walking and running.
New research from scientists in Taiwan and at Duke University has found that the mechanical properties of the pads vary in predictable fashion as animals get larger. In short, bigger critters need stiffer shoes.
Kai-Jung Chi, an assistant professor of physics at National Chung Hsing University in Taiwan ran a series of carefully calibrated "compressive tests" on the footpads of carnivores that have that extra toe halfway up the foreleg, including dogs, wolves, domestic cats, leopards and hyenas. She was measuring the relative stiffness of the pads across species – how much they deformed under a given amount of compression.
"People hadn't looked at pads," said co-author V. Louise Roth, an associate professor of biology and evolutionary anthropology who was Chi's thesis adviser at Duke. "They've been looking at the bones and muscles, but not that soft tissue."
Whether running, walking or standing still, the bulk of the animal's weight is borne on that pillowy clover-shaped pad behind the four toes, the metapodial-phalangeal pad, or m-p pad for short. It's made from pockets of fatty tissue hemmed in by baffles of collagen. Chi carefully dissected these pads whole from the feet of deceased animals (none of which were euthanized for this study), so that they could be put in the strain meter by themselves without any surrounding structures.
Laid out on a graph, Chi's analysis of 47 carnivore species shows that the area of their m-p pads doesn't increase at the same rate as the body sizes. But the stiffness of pads does increase with size, and that's what keeps the larger animal's feet from being unwieldy.
The mass of the animal increases cubically with its greater size, but the feet don't scale up the same way. "A mouse and an elephant are made with the same ingredients," Roth said. "So how do you do that?"
Earlier research had found that the stresses on the long bones of the limbs stay fairly consistent over the range of sizes, in part because of changes in posture that distribute the stresses of walking differently, Roth said. But that clearly wasn't enough by itself.
The researchers also found that larger animals have a pronounced difference in stiffness between the pads on the forelimbs and the pads on the hind limbs. Bigger animals have relatively softer pads on their rear feet, whereas in smaller animals the front and rear are about the same stiffness.
Chi thinks the softer pads on the rear of the bigger animals may help them recover some energy from each step, and provide a bit more boost to their propulsion. (Think of the way a large predator folds up its forelimbs and launches itself with its hind legs.)
"It is as if the foot pads' stiffness is tuned to enhance how the animal moves and how strength is maintained in its bones," Roth said.
The research appears today in the Journal of the Royal Society, Interface. It was supported by the National Science Foundation.
Chi has new work under way that looks at the construction of the human heel in the same ways.
Karl Leif Bates | EurekAlert!
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
03.07.2018 | Event News
17.07.2018 | Information Technology
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A dramatic magnetic energy wrestle at the Sunlight’s area lies at the coronary heart of solar eruptions, new research using NASA info shows. The operate highlights the function of the Sunshine’s magnetic landscape, or topology, in the growth of solar eruptions that can cause room weather conditions activities around Earth.
The scientists, led by Tahar Amari, an astrophysicist at the Middle for Theoretical Physics at the Ecole Polytechnique in Palaiseau Cedex, France, deemed solar flares, which are intensive bursts of radiation and light-weight. A lot of powerful solar flares are followed by a coronal mass ejection, or CME, a substantial, bubble-formed eruption of photo voltaic substance and magnetic area, but some are not – what differentiates the two scenarios is not obviously comprehended.
Utilizing knowledge from NASA’s Photo voltaic Dynamics Observatory, or SDO, the scientists examined an Oct 2014 Jupiter-sized sunspot group, an region of complex magnetic fields, frequently the internet site of photo voltaic action. This was the greatest team in the earlier two solar cycles and a highly lively region. Even though conditions seemed ripe for an eruption, the location never made a major CME on its journey throughout the Sun. It did, however, emit a powerful X-class flare, the most intensive class of flares. What determines, the experts puzzled, whether a flare is linked with a CME?
The group of scientists provided SDO’s observations of magnetic fields at the Sun’s surface area in effective designs that estimate the magnetic discipline of the Sunlight’s corona, or higher atmosphere, and examined how it advanced in the time just before the flare. The model reveals a battle among two important magnetic buildings: a twisted magnetic rope – identified to be connected with the onset of CMEs – and a dense cage of magnetic fields overlying the rope.
The experts identified that this magnetic cage bodily prevented a CME from erupting that working day. Just hrs just before the flare, the sunspot’s natural rotation contorted the magnetic rope and it grew more and more twisted and unstable, like a tightly coiled rubber band. But the rope never ever erupted from the area: Their model demonstrates it didn’t have sufficient energy to break through the cage. It was, nonetheless, risky adequate that it lashed through component of the cage, triggering the strong photo voltaic flare.
By changing the circumstances of the cage in their model, the experts found that if the cage had been weaker that day, a significant CME would have erupted on Oct. 24, 2014. The group is intrigued in even more building their product to research how the conflict amongst the magnetic cage and rope performs out in other eruptions. Their findings are summarized in a paper revealed in Nature on Feb. eight, 2018.
“We had been ready to stick to the evolution of an lively area, forecast how most likely it was to erupt, and determine the greatest sum of energy the eruption can launch,” Amari mentioned. “This is a functional method that could become important in area climate forecasting as computational capabilities enhance.”
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Pulsating aurora mysteries uncovered with assist from THEMIS and ERG missions
Greenbelt MD (SPX) Feb 21, 2018
Occasionally on a dark night in close proximity to the poles, the sky pulses a diffuse glow of inexperienced, purple and red. Unlike the lengthy, shimmering veils of normal auroral displays, these pulsating auroras are a lot dimmer and considerably less common. Although researchers have extended recognized auroras to be associated with photo voltaic action, the specific system of pulsating auroras was unknown.
Now, new study, employing data from NASA’s Time Heritage of Functions and Macroscale Interactions for the duration of Substorms – or THEMIS – mission and Japan’s Explo … read far more | <urn:uuid:b21cfa3c-e977-47ae-ae98-b2127cf92101> | 3.328125 | 994 | News Article | Science & Tech. | 30.060767 | 95,621,379 |
Catalysts are everywhere. They make chemical reactions that normally occur at extremely high temperatures and pressures possible within factories, cars and the comparatively balmy conditions within the human body. Developing better catalysts, however, is mainly a hit-or-miss process.
By precisely designing a series of nanocrystals with different sizes, shapes and compositions, researchers showed that the efficiency of certain catalysts depends on the interface between their two materials.
Now, a study by researchers at the University of Pennsylvania, the University of Trieste and Brookhaven National Laboratory has shown a way to precisely design the active elements of a certain class of catalysts, showing which parameters are most critical for improving performance.
This highly controlled process could be a new paradigm for fine-tuning catalysts used in everything from making new materials to environmental remediation.
The research is the result of a highly collaborative effort between the three institutions. It was led by Christopher Murray, a Penn Integrates Knowledge Professor with appointments in the Department of Chemistry in the School of Arts and Sciences and the Department of Materials Science and Engineering in the School of Engineering and Applied Science, and Matteo Cargnello, a postdoctoral fellow in Murray's group. Cargnello was a graduate student in Paolo Fornasiero's group at the University of Trieste when the research began and also worked with Raymond Gorte, professor in the Department of Chemical and Biomolecular Engineering, after coming to Penn. Penn graduate students Vicky Doan-Nguyen and Thomas R. Gordon, as well as Brookhaven's Rosa Diaz and Eric Stach, also contributed to the study.
It was published in the journal Science.
Murray's team set out to improve the process for designing a class of reaction-promoting materials known as supported catalysts. These catalysts are made of two different solid substances—one supporting the other—but existing techniques for fabricating them don't provide much in the way of precisely controlling their parameters. Because of the lack of uniformity in conventional catalysts, it can be difficult to tell which aspects of their combination lead to better systems.
"In putting together materials design, functional testing and state-of-the art-characterization tools, we're looking to develop a feedback loop," Murray said. "Improving our understanding about the active components of these catalysts can tell us what to emphasize in future systems."
Capitalizing on the Murray lab's expertise in creating nanocrystals with precisely defined sizes, shapes and compositions, the researchers created a series of supported catalysts and tested them against one another on a model catalytic reaction: the oxidation of carbon monoxide.
This basic example of catalysis is also common in real-world applications, as it turns carbon monoxide, which is toxic, into carbon dioxide. Carbon monoxide is a common byproduct of the incomplete combustion of organic compounds, so it is produced in car engines and many industrial processes. Catalytic filters and converters are often required by law to cut down carbon monoxide pollution.
Catalysts are often used for this reaction as simply adding carbon monoxide and oxygen in an enclosed chamber is not sufficient to cause them to combine. Without additional pressure or heat—up to several hundreds of degrees Celsius—the gas molecules do not collide frequently or energetically enough to produce carbon dioxide.
Adding a catalyst is a more efficient alternative to adding heat or pressure. The catalyst materials are not consumed during the reaction but provide a template of sorts that helps the reactants find one another and bond. This active material is typically a metal, as metallic elements are able to form many kinds of bonds. Increasing the surface area of this material increases the reaction rate, as it provides more places for the reacting molecules to bond, so the metal is often broken down to as small particles as possible.
These small metal particles are often deposited on the second material—a support—which is typically made of a metal oxide. Supports are generally inert, simply providing a thermally stable platform for the metal particles, but some are "active" in that they are also involved in the bonds that speed along the catalytic reaction. For carbon monoxide oxidation using active supports, it is theorized that the metal particles hold carbon monoxide molecules while the support donates oxygen molecules, bringing the two gases together in a more consistent and faster way than if both had to bond to the metal alone.
This theory would suggest that increasing the percentage of atoms at the interface between the metal particles and the support is more important than increasing the surface area of the metal.
"For this family of supported catalysts, however, we had only fragmentary knowledge about what regions of the whole catalytic system are critically active," Murray said. "Now, with better tools and the ability to make better samples, we can go in and pull out the things that really matter."
To test the theory, the researchers made nanocrystals of three sizes with three metals: nickel, palladium and platinum. They then deposited these nanocrystals on both an inert support, aluminum oxide, and an active support, cerium oxide. Transmission electron microscopy, performed at Brookhaven, was critical in enabling the researchers to confirm each of the 18 combinations came together correctly prior to comparing their performances in the carbon monoxide oxidation reaction.
The results began to confirm their hypothesis.
"For the aluminum oxide support," Cargnello said, "there was basically no difference in the catalytic activity between the different sizes of particles when normalized per number of metal atoms, which is what the literature has suggested for the past few decades. The surprise came when, in Trieste, we tested the cerium oxide supported samples, where we found that the smaller particles were more active than the larger ones, on the same basis. That means that structural differences in the particles were related to the different active sites for the reaction."
Returning the 18 combinations to Brookhaven, the researchers used the transmission electron microscope to create a computer model of the interfaces between the nanocrystals and supports. Able to count the individual atoms in this model, they saw that, the greater the proportion of a nanocrystal's atoms were at the interface with the support, the better it performed.
"We saw this proportion made a much bigger difference in the catalyst performance than the material the nanocrystals were made of," Cargnello said. "This is important in that nickel is much less expensive than platinum and palladium, so, if we can figure out how to fine-tune nickel nanocrystals, we may be able to make much cheaper catalysts that work just as well."
More than showing a path to improving this particular reaction, the study represents a new way of studying catalytic reactions in general, as well as a more straight-forward way of designing the materials at their core.
"We're flipping the vision of catalysis," Cargnello said. "Usually, people see that a material performs well, then study its structure to determine why it behaves the way it does. Here, we're preparing the structure based on how we think the material is going to be behave, then see how it performs."
The research was supported by European Cooperation in Science and Technology, the U.S. Department of Energy through its Office of Basic Energy Sciences and its Advanced Research Projects Agency, the National Science Foundation through Penn's Nano/Bio Interface Center and the Air Force Office of Scientific Research.
Thomas R. Gordon is now a postdoctoral fellow at Pennsylvania State University.
NOTE: This press release was issued by the University of Pennsylvania. Scientists Rosa Diaz and Eric Stach of Brookhaven National Laboratory's Center for Functional Nanomaterials (CFN) combined results from two electron microscopes to reveal crucial information on the size and configuration of the catalysts. The collaboration correlated the CFN structural analysis with reactivity tests to determine the active sites of the catalysts.
University of Pennsylvania Media contact: Evan Lerner at email@example.com
Justin Eure | Newswise
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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Edited By: SH Schneider, A Rosencranz, MD Mastrandrea and K Kuntz-Duriseti
522 pages, b/w photos, b/w illustrations, tables
This book features 49 individual chapters by some of the world's leading climate scientists. Its five sections address climate change in five dimensions: ecological impacts, policy analysis, international considerations, United States considerations and mitigation options to reduce carbon emissions.
The editors have collated information from the IPCC report as well as results of the UN Framework Convention on Climate Change held in Bali in December 2007. They reveal that climate change has progressed faster than the IPCC reports anticipated and that the outlook for the future is bleaker than first predicted.
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Here is Description! (The content won't change, but the English might be revised.)
Ions play an important role in almost all of the biological reactions. Without ions, a living organism cannot maintain their vital activity and therefore, ion strength has a huge impact on them. Devices that synthetic biology develops also affected by such a restriction.
These Devices are ever-improving and many researchers are working very hard to devise a solution for every problem we confront in this world. Among this background, controlling ion concentration sometimes become an especially vital role. For example, when you have low salt concentration, you may solve by adding salt to culture solution. However, what if the salt concentration was too high? This will be a difficult problem.
If we could develop a new device that collects sodium under a high salt concentration environment, this could become a significant tool to support bio-sensing and bio-remediation. Additionally, this device may also be applied to things such as factory disposal and salt damage. It might become a new approach to solve that kind of environmental issues.
How far can we do with biological desalination system?This question has not yet discussed fully. Thus this year, our team addressed a problem.
To deal with this problem, we bioengineered Saccharomyces cerevisiae and increased Na+ uptake system in their plasma membrane and vacuolar. Then, by expressing a mechanism that adheres to Saccharomyces cerevisiae each other on the cell wall, Saccharomyces cerevisiae which has absorbed Na + in solution is aggregated and recovered as a paste. By developing this system, we believe that a simpler and easier to use biological desalination system can be realized.
While you may not win Best Wiki with this styling, your team is still eligible for all other awards. This default wiki meets the requirements, it improves navigability and ease of use for visitors, and you should not feel it is necessary to style beyond what has been provided.----------------------------------------------------------- | <urn:uuid:40279cb0-6c3f-4d01-969e-43327d51412e> | 3.046875 | 409 | Knowledge Article | Science & Tech. | 37.967904 | 95,621,407 |
Description: Ann Hodges has the distinction of being the only human to have been hit my a meteorite. While Mrs. Hodges was napping on the couch the meteorite impacted her house, bounced off a table and hit her in the hip. She was able to walk away from the incident. Scientists can learn about the composition of the early solar system and the formation of the Earth by studying these primordial objects orbiting in space.
Web Resource: Sylacauga (meteorite) - Wikipedia | <urn:uuid:085d5a86-b0fb-4522-8ec5-5919a4c11959> | 2.5625 | 102 | Knowledge Article | Science & Tech. | 48.89 | 95,621,416 |
Influence of Sunlight on Chemical Composition of Oceanic-Derived Sea-Salt Particles in the Lower AtmosphereESF in Bermuda
Although the atmosphere is mostly comprised of gases, it also contains many particles (better known as aerosols). Individual aerosols are too small to be seen with the naked eye. However, their presence is clearly evident in the darker layer of air near the Earth's surface one often observes from the window of an airplane or by the slimy film that accumulates on the windshield of a car parked near the beach. Although small, these aerosols are quite numerous (often exceeding 1000 per square centimeter) and consequently they can have a profound affect on the Earth’s radiation balance influencing life and our climate. The oceans are the major source of aerosols mass in the lower atmosphere and one of the primary sources worldwide. Breaking waves on the ocean surface produce bubbles that, upon bursting, inject seawater constituents into the overlying atmosphere. The familiar “fizz” that one hears following a breaking wave at the beach is the sound that accompanies aerosol production.
In terms of mass, most of the sea-salt aerosols are in the 1 -10 micron diameter size-range, which persist in the atmosphere for only a few hours to a few days. Many smaller submicron-sized aerosols are also generated and, depending on meteorological conditions, these aerosols persist in the atmosphere for a week or more. Depending on their size and associated atmospheric lifetime, oceanic aerosols can be transported great distances and undergo significant chemical changes in their composition. For example, although sea salt aerosols start off at a slightly alkaline pH of 8 (which is roughly the same pH as a solution of baking soda), within minutes they pick up gas phase acids (primarily nitric and sulfuric) and become very acidic (pH 3-5, lemon juice is approximately pH 4). Because they accumulate acids over longer lifetimes, the pH of submicron aerosols is typically even lower. The low pH and interaction with sunlight cause additional chemical changes in the aerosols, which are thought to significantly influence atmospheric ozone concentrations, sulfur cycling, radiation balance and climate, and trace-metal fertilization of the surface ocean. While the scientific community is well aware that chemical changes will occur in sea-salt aerosols during their atmospheric lifetime, the details of these chemical changes are poorly known.
My colleagues at the University of Virginia (William Keene, firstname.lastname@example.org), Wadsworth Center, New York State Department of Health and School of Public Health of SUNY at Albany (Xianliang Zhou), Max Planck Institute for Chemistry (Rolf Sander), and University of Miami Rosenstiel School of Marine and Atmospheric Science (Hal Maring) and I (David Kieber) proposed a three-year field and modeling study to better understand the chemical changes that occur in sea-salt aerosols as they are exposed to sunlight. This project was comprised of two phases. The first phase was conducted at the Bermuda Institute for Ocean Sciences over the past two years. At this facility, we were able to test a large, sea salt aerosol generator (Images 1, 2 & 3), fabricated at the University of Virginia, to determine the physical and chemical properties of the sea-salt aerosols that were freshly generated from bursting bubbles. The aerosol samples that were collected were diluted in water and exposed to sunlight to quantify the production of reactive oxygen species (ROS) and to assess their impact on the processing of the organic matter in the aerosols. The amount of ROS that are produced in our studies will be compared to other known sources and chemical processes in the lower atmosphere employing a Model of Chemistry Considering Aerosols (MOCCA).
The second phase of this study is being conducted now at the Bermuda Institute for Ocean Science’s Tudor Hill Atmospheric Observatory, which consists of an atmospheric sampling tower and two trailers (Image 4) to house equipment, computers, and facilities for visiting scientists such our group (Image 5).
This site is influenced by chemically distinct air masses originating from different source regions. When under the influence of the Bermuda high during late spring through early autumn, the site is often enveloped by relatively clean marine air (with lots of sea salt aerosols) that has not been substantially modified by recent continental emissions. This site is also periodically influenced by air originating from Africa, Canada, Europe or the eastern United States all of which give rise to very different air mass types thereby giving us an opportunity to collect and examine distinct atmospheric aerosols. Many past investigations (both short- and long-term) have characterized aerosol properties at Bermuda thereby providing context for temporally extrapolating results of our study.
To collect aerosol samples, we used two types of samplers at the Tudor Hill site; both of these samplers are secured to the top of the tower (Image 6). The first sampler is called a MOUDI cascade impactor (Multi Orifice Uniform Deposit Impactor), which has ten stages to collect aerosols in different size ranges all the way from the largest aerosols greater than 10 microns to the very smallest aerosols less than approximately 0.2 microns in diameter (Image 7). Basically, the cascade impactor works by air moving around a series of plates stacked on top of each other. If an aerosol is too big, it cannot keep up with the air flow and hits (or impacts) one of the plates. As the air flows from one end of the impactor to the other end, the air velocity increases such that smaller and smaller aerosols are impacted on the plates. In Image 8, one of the stages of the disassembled impactor is shown revealing the aerosols that were impacted on the aluminum plate. The diameters of the nozzles above each impactor plate are designed in such a manner that each sampling plate collects particles of predominantly one size range. The second type of aerosol collector that we are using is a dichotomous sampler, which works on the same principle as the cascade impactor except that only two size fractions are collecteda supermicron fraction with particles above approximately 1 micron in diameter and a submicron fraction with all aerosols less than one micron. Although the dichotomous samples provides less information about the size of the aerosols, it has one distinct advantage over the MOUDI sampler in that it can collect a lot more sample (aerosols) because larger air flows through the sampler (i.e. 100 liters of air per minute vs 30 liters per minute for the MOUDI) can be achieved and the sample is partitioned into only 2 as opposed to 10 size fractions. Once the sample is collected, it is extracted from the sampler plate with water for subsequent analysis or exposure to sunlight.
So far we have obtained some very exciting results. In particular, we have shown that the oceans can be a much more important source of very small, submicron aerosols than previously thought. These are very important in the atmosphere because they can act as cloud condensation nuclei or the “seeds” for cloud formation thereby affecting both the brightness and duration of clouds and consequently our Earth’s radiation balance and ultimately climate. Second, we have shown that sea-salt aerosols can be an important source of the hydroxyl radical, which is the ultimate cleaning agent in the atmosphere, breaking down and removing organic matter in the air. We are developing a mathematical model to determine if this radical plays the same role in the processing of organic matter in sea-salt aerosols.
Results from our study will improve understanding of the fundamental processes that control the chemistry of the lower atmosphere and related influence on Earth systems such as climate. Our results will also directly benefit from and build on a number of interrelated national and international programs investigating the chemical and physical evolution of marine aerosols and their related climatic implications. The National Science Foundation (NSF) recently funded BBSR to refurbish the Tudor Hill in support of anticipated new investigations under these programs, which include the International Geosphere-Biosphere Programme’s Surface Ocean Lower Atmosphere Study (IGBP-SOLAS), U.S. SOLAS, the National Aerosol-Climate Interaction Program (NACIP), and other emerging initiatives investigating influences of the lower atmosphere on climate.
Our research has established and fostered research and educational collaborations between the faculty, staff and students at five academic institutions. A number of peer-reviewed publications are in preparation stemming from our work. Some of these future manuscripts are summarized in abstracts that were submitted to the American Geophysical Union for presentation at the upcoming fall meeting in San Francisco, CA. | <urn:uuid:42d7c73b-dbae-4d1a-8ab4-9cd3d442484e> | 3.484375 | 1,801 | Academic Writing | Science & Tech. | 22.066243 | 95,621,423 |
Washington: Contrary to earlier visualisations, the sun's heliosphere is dominated by two giant jets of material shooting backwards over the north and south poles of the sun.
The heliosphere is created by the solar wind, the changed particles emitted by the sun. The heliosphere extends far beyond the planets of the solar system. These two jets are confined by the interaction of the sun's magnetic field with the interstellar magnetic field.
"Everyone's assumption has been that the shape of the heliosphere was molded by the flow of interstellar material passing around it," said Merav Opher, astronomer at Boston University and lead author of the NASA-funded study.
Scientists have for decades visualised the heliosphere in the shape of a comet, with a very long tail extending some 464 billion miles. The two jets are similar to other astrophysical jets seen in space, so studying them locally could open doors to understanding such jets throughout the universe.
"Scientists thought the solar wind flowing down the tail could easily pull the magnetic fields in the heliosphere along as it flowed by, creating this long tail. But it turns out that the magnetic fields are strong enough to resist that pull - so instead they squeeze the solar wind and create these two jets," said Opher.
The team could determine the new shape when they adjusted simulations of the heliosphere based on observations collected from NASA's Voyager 1 spacecraft.
The spacecraft recently moved outside of the heliosphere into interstellar space. "If there were no interstellar flow, then the magnetic fields around the sun would shape the solar wind into two jets pointing straight north and south," said Jim Drake at the University of Maryland in College Park.
"If we're right about all of this, it gives us a local test bed for exploring some very important physics," Drake concluded.
The study findings were detailed in the Astrophysical Journal Letters. | <urn:uuid:77c35315-0eef-47d8-b62a-d99fffd635bc> | 4.09375 | 386 | News Article | Science & Tech. | 40.608125 | 95,621,440 |
Salt marsh harvest mouse
|Salt marsh harvest mouse|
The salt marsh harvest mouse (Reithrodontomys raviventris), also known as the red-bellied harvest mouse and sometimes called the saltmarsh harvest mouse, is an endangered rodent endemic to the San Francisco Bay Area salt marshes in California. There are two distinct subspecies, both endangered and listed together on federal and state endangered species lists. The northern subspecies (Reithrodontomys raviventris halicoetes) is lighter in color and inhabits the northern marshes of the bay, and the southern subspecies (Reithrodontomys raviventris raviventris) lives in the East and South Bay marshes. They are both quite similar in appearance to their congener species, the [Western harvest mouse, R. megalotis], to which they are not closely related. Genetic studies of the northern subspecies have revealed that the salt marsh harvest mouse is most closely related to the plains harvest mouse, R. montanus, (), which occurs now in the Midwest]. Its endangered designation is due to its limited range, historic decline in population and continuing threat of habitat loss due to development encroachment at the perimeter of San Francisco Bay.
Description and comparison to similar species
The southern population of the salt marsh harvest mouse tends to have dark brown fur above and a pinkish cinnamon or tawny belly; moreover, the tail is likewise bicolored. An adult's length is five to seven centimeters (2 to 3 inches) and a tail length of six to ten centimeters (2 to 4 inches). The height is between 1.5 and 2.1 centimeters (0.6 to 0.8 inches). Weight of a mature mouse is approximately 10 to 20 grams (0.35 to 0.7 ounces). The northern subspecies is also dorsally brown or reddish brown, but the venters tend to be white or cream, and rarely with a hint of reddish; tail length is usually about 120% of the body length. The upper incisors are grooved. As a member of the Neotominae subfamily, the dental formula of R. raviventris is 18.104.22.168 × 2 = 16.
This species is nocturnal, with particularly noted activity on moonlit nights. This mouse is particularly resourceful, making use of ground runways of other rodents; moreover, he also exhibits climbing agility. It occupies marsh habitats where pickleweed and marsh plants abound. Its many predators feature hawk, snake and owl species, as well as shorebirds and larger mammals. Predation by domestic cats is an issue due to encroachment of the limited habitat by humans at the perimeter of the San Francisco Bay.
As would be expected of a mouse native to salt marshes, this species is a competent swimmer and is tolerant of salt in its diet and water supply. It eats seeds and plants, especially pickleweed and glasswort, one of the most common salt marsh plant species.
Similar species are the Plains Harvest Mouse, and the Fulvous Harvest Mouse, which has a longer tail. The species co-occurs with the similar Western harvest mouse, which tends to have dorsal fur that is more gray than R. raviventris and with ventral fur that is white to grayish; and the House mouse which is gray, has a scaly tail and incisors without grooves, unlike those of the salt marsh harvest mouse.
Survey data from Suisun Marsh found that the salt marsh harvest mouse can live up to 18 months and possibly longer. Females commonly have two litters per year. In the summer, when salinity of water and vegetation increases, the mice have a notable advantage due to their ability to drink and survive purely on salt water. The northern species can survive purely on salt water, but prefers freshwater to saltwater. The southern species can survive on either, and does not display a preference.
The mice depend heavily on vegetation cover, particularly pickleweed and tules (Schoenoplectus spp.). Pickleweed (Salicornia virginica) is their primary and preferred habitat as well their main food source; However, R. raviventris are found in a variety of marsh habitats, including diked and tidal wetlands. The salt marsh harvest mouse is not an aggressive species; many mice live in close quarters, withstanding short durations of high population density due to seasonal flooding that restricts individuals to small patches of dry ground. They can also survive tidal or seasonal flooding due to their superior ability to swim, float and climb.
R. raviventris home range and habitat use differ temporally across age and sex. Juveniles exhibit home ranges of 600–700 m² whereas adults exhibit home ranges of 1300–1500 m². Males and females also differ in the structural complexity of their occupied habitat during fall and summer (breeding season) but occupy the same habitat during winter and spring. While the cause is still unknown, this seasonal disparity in habitat use may be related to a reduced risk of predation and intraspecific competition in more structurally complex habitats. Furthermore, movement of R.raviventris individuals within their home ranges varies seasonally, with mean distance traveled highest in June and lowest in November.
This organism is known to be found in the following specific locales (among others):
- Sonoma Creek discharge area known as the Napa Sonoma Marsh
- Suisun Marsh, Solano County
- Alman Marsh, adjacent to Shollenberger Park, Petaluma
- Sausalito baylands
- San Rafael baylands
- Arrowhead Marsh in Oakland
- San Francisco Bay sloughs in Alviso
- Palo Alto baylands
- Bair Island
- Point Reyes National Seashore
The salt marsh harvest mouse has lost much of its habitat to extensive development of bayside marshland, pollution, boat activity, and commercial salt harvesting. It has been on the endangered lists since the 1970s, and has protected habitat within numerous Bay Area wildlife refuges. Individual political jurisdictions have conducted research and established habitat protection strategies to protect the salt marsh harvest mouse. For example, the city of San Rafael, California has established a shoreline setback standard to prevent any land development within fifty feet of the shoreline; this measure has been applied to several specific land developments along the San Francisco Bay shoreline. Researchers like Katherine Smith of California Department of Fish and Game are at the forefront of research helping to identify how threats like climate change impact the species while increasing the understanding of its biology, ecology and behavior.
Reference in 2009 economic stimulus debate
The preservation of the salt marsh harvest mouse habitat was a subject of discussion in 2009 Economic Stimulus package. The mouse was mentioned numerous times in Congress by Republicans such as Rep. Mike Pence and Rep. Dan Lungren to highlight the wasteful spending of the bill. It was claimed that $30m of the 2009 economic stimulus would be spent on habitat restoration to protect the mouse. The rumor was apparently started by Michael Steel, press secretary for John Boehner. This was disputed in a San Francisco Chronicle article by Democratic U.S. Rep Jackie Speier.
- Whitaker Jr., J.O.; Hammerson, G.; Williams, D.F. & NatureServe (2008). "Reithrodontomys raviventris". The IUCN Red List of Threatened Species. IUCN. 2008: e.T19401A8875959. doi:10.2305/IUCN.UK.2008.RLTS.T19401A8875959.en. Retrieved 27 December 2017.
- Musser, G. G. and M. D. Carleton. 2005. Superfamily Muroidea. Mammal Species of the World a Taxonomic and Geographic Reference, D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore
- Presentation by Sarah Brown: Conservation genetics of salt marsh harvest mice (Reithrodontomys raviventris). Presented at College of Science and Math Symposium, California State University, San Luis Obispo. 5/01
- Sustaita et al. Salt marsh harvest mouse demography and habitat use in the Suisun Marsh, CA. Journal of Wildlife Management, Vol. 75, Issue 6, pp 1498-1509. August 2011.
- Wilson, Don E.; Reeder, DeeAnn M. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference. JHU Press. ISBN 9780801882210.
- Golovanova, Galina. The Biogeography of the Salt Marsh Harvest Mouse (Reithrodonomys raviventris).
- Sustaita, Diego; Quickert, Patty Finfrock; Patterson, Laura; Barthman-Thompson, Laureen; Estrella, Sarah (2011-08-01). "Salt marsh harvest mouse demography and habitat use in the Suisun Marsh, California". The Journal of Wildlife Management. 75 (6): 1498–1507. doi:10.1002/jwmg.187. ISSN 1937-2817.
- Geissel, W.; Shellhammer, H.; Harvey, H. T. (1988-11-29). "The Ecology of the Salt-Marsh Harvest Mouse (Reithrodontomys raviventris) in a Diked Salt Marsh". Journal of Mammalogy. 69 (4): 696–703. doi:10.2307/1381624. ISSN 0022-2372.
- Bias, Michael A.; Morrison, Michael L. (2006-06-01). "Habitat Selection of the Salt Marsh Harvest Mouse and Sympatric Rodent Species". Journal of Wildlife Management. 70 (3): 732–742. doi:10.2193/0022-541X(2006)70[732:HSOTSM]2.0.CO;2. ISSN 0022-541X.
- Bias, Michael A.; Morrison, Michael L. (1999). "Movements and Home Range of Salt Marsh Harvest Mice". The Southwestern Naturalist. 44 (3): 348–353. JSTOR 30055230.
- "Threatened & Endangered Animal Species of Point Reyes" (PDF). National Park Service. Retrieved 25 September 2016.
- Hogan, C. Michael et al. (1989). Spinnaker-on-the-Bay Expanded Initial Study, Earth Metrics Inc., prepared for the city of San Rafael, California
- "Researchers seek secrets of Suisun salt marsh harvest mouse". Daily Republic. 2011-06-24. Retrieved 2017-04-20.
- "Salt-Water Science up Close". UC Davis. Retrieved 2017-04-20.
- Mentions of the Mouse. Metavid.org (2009-02-13). Retrieved on 2012-12-30.
- Mercury News: Bay Area mouse spurs national debate over stimulus bill. February 13, 2009.
- Erbe, Bonnie. Republicans Flop On Pelosi Mouse Lie, Haven't Learned Environmental Lesson. CBS News. 13 February 2009.
- Speier, Jackie (14 February 2009). The myth of the 'San Francisco mouse'. sfgate.com
- National Audubon Society Field Guide to North American Mammals, ed. by John O. Whitaker Jr., Chanticleer Press (1997) ISBN 0-679-44631-1
- Shellhammer (2000). "Reithrodontomys raviventris". IUCN Red List of Threatened Species. Version 2006. International Union for Conservation of Nature. Retrieved 11 May 2006. Database entry includes a brief justification of why this species is vulnerable and the criteria used
- Shellhammer, Howard. "A marsh is a marsh is a marsh . . . but not always to a salt marsh harvest mouse" (PDF). Retrieved 7 September 2016.
- Smith, Katherine. (2014) "Effects of Natural and Anthropogenic Change on Habitat Use and Movement of Endangered Salt Marsh Harvest Mice" | <urn:uuid:50cb304d-5801-4c85-9d72-c5aeb49a6b8b> | 3.015625 | 2,540 | Knowledge Article | Science & Tech. | 55.733457 | 95,621,441 |
There are some great tools available to anyone who wants to do math, regardless of the level involved. And whether it’s a calculator, spreadsheet or software package, they don’t just cater to time-savers. Many are programmable and therefore thought-provoking. But in the old days of hand-calculations, people did not necessarily surrender to tedium. They often came up with shortcuts, some of which were excellent approximations, while others gave an exact result. Let’s look at an example of each variety.
Whether you’re on a plane, hill or mountain, if you know your altitude, what is the easiest way of calculating the distance to the horizon?
It turns out you don’t have to resort to the tangent to a circle and the Pythagorean theorem. The shortcut consists of multiplying the altitude in feet by 1.5 (its units not shown) and to square root the product. The answer is a close approximation of the distance in miles!
To understand why the shortcut works we need to look at the longer and more accurate way of solving the problem. The distance, d, from an altitude, h, is simply the leg of a right-angled triangle. One angle is 90 degrees because the line of sight is tangent to the radius (R) of the earth, an approximate circle. Finally the hypotenuse is the sum of R and h.
Since d² + R² = (h+R)², after expanding and eliminating the common R² term, we obtain:
d² = h² + 2hR
The radius of the earth is about 3959 miles and there are 5280 feet in a mile, so plugging in R and solving for d we obtain
d = √( h² + 41 807 040 h ) in feet.
But the trick claims that d =√(1.5h) in miles. Converting to feet ,
Equating the two expressions for d:
√( h² + 41 807 040 h) = 5280√(1.5h).
Squaring both sides:
h² + 41 807 040 h = 5280²(1.5)h.
Dividing through by h and simplifying the right hand side:
h + 41 807 040 = 41 817 600.
For any h value between 1 and 40 000 feet, the left hand sum will differ from the right hand side by a maximum of 0.07%. And so the trick works well. But how was it devised?
My guess is that if someone plotted various values of height in feet versus the distance in miles using the Pythagorean expression, she would have noticed a square root function going through the origin of the form y = a√h, where a is constant. To verify it, she likely calculated successive changes in distance per changes in the square roots of height. I’ve tried that and I obtained values in the neighborhood of 1.224 and 1.225. Then all she had to do was recognize that those values are pretty close to the square root of 1.5.
The second shortcut is a simple algorithm for computing averages mentally. I came up with it independently when I was a high school student, and needless to say this trick has also occurred to many other people!
Instead of adding up values x1, x2, x3 …. xn and dividing by the number of values, n, if you have no calculator, we begin with a convenient estimate. Then add up the differences from the estimate, divide the sum by n and add the result to the estimated value. For example, for the average of 78, 82, 97, 60 and 77, we could use an estimate of 80. The differences from the values are -2, +2, +17, -20 and -3. Mentally the numbers are smaller so it’s easy to come up with the sum of -6. Finally the average is -6/5 + 80 = -1.2 + 80 = 78.8, also a very feasible mental calculation.
Here’s why it works. Let E = estimate for the average(Xavg) of an n number of values: x1, x2, x3…xn
The first step involves adding up the differences (call the sum Sd) from E:
x1 – E + x2 – E + x3 – E… + xn – E = Sd = x1 + x2 + x3 … + xn – nE
The we divide through by the sum by n:
Sd/n = (x1 + x2 + x3 … + xn – nE)/n = (x1 + x2 + x3 … + xn)/n – nE /n.
But on the right hand side , the first term is the definition of average, so:
Sd/n = Xavg – E
Or Xavg = Sd/n + E
And how did I and others devise such a trick? Intuitively, at least that’s how I came up with it, from what I recall. That’s is even more fun than trying to figure out how someone else stumbled upon it. | <urn:uuid:adc1bda9-33b7-40a0-a127-35d923ece006> | 3.75 | 1,114 | Personal Blog | Science & Tech. | 80.920395 | 95,621,447 |
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Astronomy Lesson 49: The Solar Neutrino Problem
Here we learn how the Standard Model of Physics was tested, and how the existence of fusion in the core of the Sun was actually determined. This led to two Nobel Prizes, and a lot of dry-cleaning fuild down a deep, deep hole.
- Proton–proton chain reaction
- The Solar Neutrino problem
- Homestake experiment
- Raymond Davis Jr.
- Sudbury Neutrino Observatory
- Super-Kamiokande neutrino detector
- Neutrino oscillation
- Standard Model of Particle Physics | <urn:uuid:0ffb05aa-a396-4ca0-8144-c562b4786a42> | 3.796875 | 142 | Content Listing | Science & Tech. | 23.807778 | 95,621,455 |
Reverse osmosis (RO) is one of the most feasible methods of desalination to produce a supplemental freshwater supply. Because traditional RO desalination is energy-intensive, it is not a viable solution for remote Pacific islands where electricity is also in short supply. The utilization of wind power holds promise as a solution to this problem, as most of these remote islands are subject to constant trade winds. RO desalination of brackish groundwater, which is available in many of these islands, requires low feed water pressure that can be delivered by wind power at a moderate wind speed. Testing of a prototype wind-powered RO desalination system constructed on Coconut Island, a small island off the windward coast of Oahu, Hawaii, indicated that at an average wind speed of 8.5 m/s, a freshwater flow of over 4000 L/d can be produced. This volume is sufficient to meet the freshwater needs of a typical remote island community.
System development and testing of wind-powered reverse osmosis desalination for remote Pacific islands
C.C.K. Liu, R. Migita, J.-W. Park; System development and testing of wind-powered reverse osmosis desalination for remote Pacific islands. Water Science and Technology: Water Supply 1 April 2002; 2 (2): 123–129. doi: https://doi.org/10.2166/ws.2002.0054
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Introduction to Attractors and Chaos
Recall that a Newtonian deterministic system is a system whose present state is fully determined by its initial conditions (at least, in principle), in contrast to a stochastic (or, random) system, for which the initial conditions determine the present state only partially, due to noise, or other external circumstances beyond our control. For a stochastic system, the present state relects the past initial conditions plus the particular realization of the noise encountered along the way. So, in view of classical science, we have either deterministic or stochastic systems.
KeywordsPeriodic Orbit Lyapunov Exponent Chaotic System Hopf Bifurcation Phase Portrait
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Gecko-Tech Device Creates Real Life Spiderman
It seems that superpowers aren't just for comic book heroes. The Defense Advanced Research Projects Agency (DARPA) has created a pair of paddles that replicate Spiderman's wall-climbing abilities, a device that could allow US troops to do the same.
While many associate the ability to scale walls with the Marvel hero, DARPA officials were actually inspired by geckos.
Their Z-Man program has demonstrated that, much like a gecko, a 218-pound man carrying a 50-pound load could climb a 25-foot vertical glass wall without ropes or hooks. The novel polymer microstructure technology used in those paddles was developed for DARPA by Draper Laboratory of Cambridge, Mass.
Z-Man looks to nature for inspiration in improving the safety and effectiveness of how warfighters navigate urban environments in combat.
"Historically, gaining the high ground has always been an operational advantage for warfighters, but the climbing instruments on which they're frequently forced to rely - tools such as ropes and ladders - have not advanced significantly for millennia," according to a DARPA news release.
In the animal world, geckos come already equipped with sticky feet, making them some of nature's best climbers. Their appendages are covered in hundreds of microscopic bristles, each topped off with a patch of even smaller fibers called spatulae. This enables them to stick to any surface, Live Science reported.
"The gecko is one of the champion climbers in the Animal Kingdom, so it was natural for DARPA to look to it for inspiration in overcoming some of the maneuver challenges that U.S. forces face in urban environments," said Matt Goodman, the DARPA program manager for Z-Man, in the news release.
The paddles developed by researchers for the Z-Man program don't stick and unstick quite as seamlessly as gecko feet, DARPA officials said. First off, the average man weighs about 375 times more than a gecko. To account for this weight disparity, climbers using the gecko-tech device push both up and away from the climbing surface.
The first successful climb was in Feb. 2012, but tests are still ongoing. | <urn:uuid:c6bfe738-e146-4129-8ec1-c7a20727470d> | 2.921875 | 459 | News Article | Science & Tech. | 42.260627 | 95,621,484 |
The same instruments used in the Nobel Prize-winning discovery of gravitational waves caused by colliding black holes could help unlock the secrets of dark matter, scientists, including one of Indian origin, say.
Dark matter is a mysterious and as-yet-unobserved component of the universe. Its nature remains unknown, but scientists estimate that it is five times as abundant as ordinary matter throughout the universe.
"It is remarkable that we can now do particle physics - investigate the "very small" - by looking at gravitational- wave emission from black holes, the largest and simplest objects in the universe," Berti said.
The research, published in the journal Physical Review Letters, details calculations by a global team of scientists which show that gravitational-wave interferometers can be used to indirectly detect the presence of dark matter.
Calculations show that certain types of dark matter could form giant clouds around astrophysical black holes, said researchers, including UM graduate student Shrobana Ghosh.
If ultralight scalar particles exist in nature, fast- spinning black holes would trigger the growth of such scalar "condensates" at the expense of their rotational energy.
This will produce a cloud that rotates around the black hole, now more slowly-spinning, and emits gravitational waves, pretty much like a giant lighthouse in the sky, they said.
"One possibility is that dark matter consists of scalar fields similar to the Higgs boson, but much lighter than neutrinos," said Paolo Pani, scientist at UM.
"This type of dark matter is hard to study in particle accelerators, such as the Large Hadron Collider at CERN, but it may be accessible to gravitational-wave detectors," Pani said.
The team studied gravitational waves emitted by the "black hole plus cloud" system.
Depending on the mass of the hypothetical particles, the signal is strong enough to be detected by the Laser Interferometer Gravitational-wave Observatory in the US, and its European counterpart Virgo, as well as by the future space mission Laser Interferometer Space Antenna.
"Surprisingly, gravitational waves from sources that are too weak to be individually detectable can produce a strong stochastic background," said Richard Brito, who led the study.
"This work suggests that a careful analysis of the background in LIGO data may rule out - or detect - ultralight dark matter by gravitational-wave interferometers," Brito said. | <urn:uuid:16b218c5-eab5-4bdb-8826-16fa579dcfdd> | 3.765625 | 508 | News Article | Science & Tech. | 21.764888 | 95,621,491 |
Just as ooding threats need to be factored into coastal community planning initiatives, so too should sea level change. Unfortunately, the “one size ts all” approach does not work.
The level of uncertainty represented in sea level projections is one challenge. Furthermore, universal projections can’t be uniformly applied to all communities because of the many local variables. These variables include subsidence or uplift, and changes in estuarine and shelf hydrodynamics, regional oceanographic circulation patterns, and river ows. Local calculations are needed.
Then add in the local response, where many variables come into play as well. Even if two communities have similar projection numbers, their responses are likely to be widely di erent because of the external factors speci c to their locations that must be considered, such as anticipated local risk, community will, and the type of planning process in which the numbers will be used.
Incorporating sea level change into planning processes involves more than selecting a number. That is why this document advocates the scenario approach.
Using the information provided here, communities can develop a process that incorporates a range of possibilities and factors. With this information various scenarios can be developed, both in terms of projections and responses, to meet the speci c circumstances of a community. Moreover, working through the scenario development process provides the data and information that o cials will need to make communities readily adaptable to changing circumstances. | <urn:uuid:81972575-3fd8-471d-8986-5e33cf4d5ef9> | 2.765625 | 293 | Knowledge Article | Science & Tech. | 20.28427 | 95,621,492 |
Herbivory and Light
In Chapter 5, the light climate within the rainforest was assessed within the vicinity of a leaf-cutting ant colony. These measurements highlighted the enormously variable light conditions both vertically through the canopy and near the forest floor. Since the cutting of leaves by ants affects canopy structure and subsequent light penetration (Plates 12, 13), the significance of this foliage removal to the light climate and primary production of the canopy becomes an interesting issue. As mentioned earlier, light availability may limit growth and survival of many plant species by limiting photosynthesis, and heterogeneity in the light environment may be an important functional attribute of the rainforest ecosystem. This chapter focuses on the measurable consequences of leaf harvesting by ants on the canopy light climate and potential primary production.
KeywordsPhotosynthesis Rate Compensatory Growth Light Extinction Light Climate Canopy Photosynthesis
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About the project
QRIScloud’s fast and accessible data storage is making a positive difference to a global climate change research project involving Queensland’s James Cook University.
The Wallace Initiative, named after ecologist Alfred Russell Wallace, is investigating which areas, species and crops are likely to be the most and least affected by climate change in the future.
The project involves researchers from JCU, Sydney’s Macquarie University and the Tyndall Centre for Climate Change Research at England’s University of East Anglia.
Associate Professor Jeremy VanDerWal has taken advantage of the 1.3 petabytes of QRIScloud storage allocated to JCU’s Centre for Tropical Biodiversity and Climate Change.
Over the last two months, he and his research team have generated more than 800 TB of data consisting of climate change impact models for more than 90,000 species globally at a 20km resolution given nine greenhouse gas emission scenarios.
The Wallace data helped QRIScloud’s Townsville node hit a milestone in late October 2015 with 1 PB of collections data ingested.
The QRIScloud Townsville team—Prof Ian Atkinson, Jay van Schyndel and Wayne Mallett—worked closely with researchers, such as Dr VanDerWal, to accelerate the data ingest in the Townsville Tropical Hub node.
Dr VanDerWal says, “The Wallace Initiative started six years ago but for the first version, we were limited by storage capacity. With QRIScloud we can now do the research as we want to do it.”
Before using QRIScloud, much of the data was offline on tape. “It was painful to interrogate the data—it could take 30 seconds to 30 minutes to retrieve a file—and we weren’t getting uptake with it by other researchers. We had to have everything so compressed and store a reduced subset of the model outputs,” says Dr VanDerWal.
QRIScloud involves live disk storage, not tape files: “The speed is a huge benefit for us, we’ve got immediate access to everything. The ease of access has made it 1,000 times better. All of my JCU team and external colleagues can run different analyses and access the data all at the same time—it has that capacity.”
“We’re starting to see an increased interest and uptake by other researchers of this data. We’ve got more people interrogating this data in novel ways and interpreting the outputs in new ways. This is what this data is fit for—it’s now a resource we can be mining information from.”
Wallace Initiative researchers plan to produce eight papers based on the data over the next year, as well as a number of policy reports, including for the Intergovernmental Panel on Climate Change.
While this data is only two months old, QRIScloud supported JCU’s climate change research outputs that have influenced Queensland Government policy and on-ground actions that are protecting biodiversity resources for the future.
For Dr VanDerWal, reaching new audiences and impacting policy is the most exciting aspect of this research. “That’s where I see the benefits, going beyond Australia and trying to influence policy globally. I’m passionate about that—influencing how people see climate change.”
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When it comes to choosing their wintering destinations Antarctic skuas are flexible. This is shown in a study of an international research team led by the polar-ornithologist Dr. Hans-Ulrich Peter from the Friedrich Schiller University Jena (Germany). According to the study, a great part of the South Polar skuas spend the Antarctic winter in the Northern Atlantic. At the same time about one third of the same species overwinters in the Northern Pacific, tens of thousands of miles away.
South Polar skua with geolocator (right leg).
Photo: Matthias Kopp/FSU
In order to identify the flight routes of the birds, postgraduate Matthias Kopp, under the guidance of Dr. Peter, equipped South Polar skuas with geolocators in their breeding areas on King George Island, about 120 kilometers off the Antarctic Mainland. Thus he has been screening their position data over a period of several years, followed by an analysis together with British colleagues and a scientist from Switzerland. “With the help of these data we can now for the first time definitely say that the South Polar skuas are not overwintering, like their close relatives, the brown skuas, off the Argentine coast but mainly in the northern hemisphere”, explains the head of research, Dr. Peter. So far the scientists could only speculate about where the birds overwinter and which routes they are heading for. “The observation of single birds led us to the assumption that they overwinter in the Atlantic. But so far it wasn’t known that a great part of them stay as well in the middle of the Northern Pacific in the winter”, says the Jena scientist who has been researching in Antarctica since 1983 on a regular basis.
No matter, which ocean the birds are heading towards for overwintering, their flight routes show remarkable similarities. Thus the flight routes from the north and the return travel to the south are always shaped like a slip knot crossing on the equator. On both flights together the birds showed a big figure-of-eight flight pattern. At first the skuas which are overwintering in the Atlantic fly on a wide corridor northwards along the east coast of South America, and then change direction after having passed the equator and head towards the northwest. At the end of May they arrive at their destination in the Northern Atlantic. In the three months they spent on the open sea they wander along with the wind and the ocean current for more than 1,000 kilometers in a eastward direction, before they start their return flight in end-August. Before arriving at their breeding sites on King George Island they have a stop-over. For up to three weeks the birds are resting off the Patagonian coast and refill their body reserves.
The flight route into the North Pacific leads at first along the coast of South America and then changes direction towards the northwest above the equator. In mid-May, two weeks earlier than their conspecifics overwintering in the Atlantic, the skuas arrive at their winter quarters in the Pacific. These animals too, let themselves drift along with the wind and the waves up to 3,000 kilometers eastwards. Their way back leads them in a wide curve in a southwestern direction towards New Zealand and finally turns in a southeasterly direction into Antarctica. There, they are resting for a few days as well before they return to their breeding site. “We think that the animals need this resting phase to recover from the strain of the long trip through the tropics where food is scarce”, Dr. Peter says.
Once the skuas have decided on an ocean for a winter quarter, they will head towards the same destination in the following years as well. Until now the scientists didn’t know the ultimate reason for the animals’ decision on one particular direction. ”We know for sure though that the animals get their own bearings and don’t learn the route from their parents”, Dr. Peter says. And so for him and his colleagues some questions still remain unanswered. Therefore the Jena scientist will leave for a research trip to Antarctica this year – 100 years after Roald Amundsen, the first person ever to reach the South Pole. Two of Dr. Peter’s students are already on site and have captured the first Skuas. For Hans-Ulrich Peter it is he 22th expedition to the world’s most southern continent.Contact:
Dr. Ute Schönfelder | idw
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Working with colleagues at Caltech, Stanford and the Howard Hughes Medical Institute, a Duke University bioengineer has developed a living system using genetically altered bacteria that he believes can provide new insights into how the population levels of prey influence the levels of predators, and vice-versa.
The Duke experiment is an example of a synthetic gene circuit, where researchers load new "programming" into bacteria to make them perform new functions. Such re-programmed bacteria could see a wide variety of applications in medicine, environmental cleanup and biocomputing. In this particular Duke study, researchers rewrote the software of the common bacteria Escherichia coli (E. coli.) to form a mutually dependent living circuit of predator and prey.
The bacterial predators don't actually eat the prey, however. The two populations control each others' suicide rates.
“We created a synthetic ecosystem made up of two distinct populations of E. coli, each with its own specific set of programming and each with the ability to affect the existence of the other,” said Lingchong You, assistant professor of biomedical engineering at Duke’s Pratt School of Engineering and member of Duke’s Institute for Genome Sciences and Policy. “This ecosystem is quite similar to the traditional predator-prey relationship seen in nature and may allow us to explore the dynamics of interacting populations in a predictable manner.”
The results of You’s study appear April 15 in the journal Molecular Systems Biology. The research was supported by National Institutes of Health, the Defense Advanced Research Projects Agency, the Howard Hughes Medical Institute, and the David and Lucile Packard Foundation.
This field of study, known as synthetic biology, emerged on the scientific scene around 2000, and many of the systems created since have involved the reprogramming of single bacteria. The current circuit is unique in that two different populations of reprogrammed bacteria live in the same ecosystem and are dependent on each other for survival.
“The key to the success of this kind of circuit is the ability of the two populations to communicate with each other,” You said. “We created bacteria representing the predators and the prey, with each having the ability to secrete chemicals into their shared ecosystem that can protect or kill.”
Central to the operation of this circuit are the numbers of predator and prey cells relative to each other in their controlled environment. Variations in the number of cells of each type trigger the activation of the reprogrammed genes, stimulating the creation of different chemicals.
In this system, low levels of prey in the environment cause the activation of a “suicide” gene in the predator, causing them to die. However, as the population of prey increases, it secretes into the environment a chemical that, when it achieves a high enough concentration, stimulates a gene in the predator to produce an “antidote” to the suicide gene. This leads to an increase in predators, which in turn causes the predator to produce another chemical which enters the prey cell and activates a “killer” gene, causing the prey to die.
“This system is much like the natural world, where one species – the prey – suffers from growth of another species – the predator,” You said. “Likewise, the predator benefits from the growth of the prey.”
This circuit is not an exact representation of the predator-prey relationship in nature because the prey stops the programmed suicide of predator instead of becoming food, and both populations compete for the same “food” in their world. Nevertheless, You believes that the circuit will become a useful tool for biologic researchers.
“This system provides clear mapping between genetics and the dynamics of population change, which will help in future studies of how molecular interactions can influence population changes, a central theme of ecology,” You said. “There are literally unlimited ways to change variables in this system to examine in detail the interplay between environment, gene regulation and population dynamics.
“With additional control over the mixing or segregating of different populations, we should be able to program bacteria to mimic the development and differentiation of more complex organisms,” he said.
Richard Merritt | EurekAlert!
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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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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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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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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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There’s a pretty story we tell ourselves about environmental problems: Once you fix them, they immediately start to improve.
Smog works like this. In cities where air quality is a problem, smog tends to worsen on weekdays, because millions of people are commuting and factories are fully productive. On weekends, when fewer people drive, the air tends to clear.
Likewise, when the country chose to address its smog problem, it got better. In 1970, Congress passed the Clean Air Act and told the EPA to start regulating air pollution. Smog across the country began to dissipate, and certain lung conditions became less common. Air pollution is not the problem today that it was in the 1960s and early 1970s because the United States addressed it.
It is a pleasant story. It’s true for some issues. For global warming, it is a fable.
Greenhouse gases released into the atmosphere today will cause the seas to rise for centuries to come, even if those gases leave the atmosphere relatively rapidly, finds a new study published Monday in the Proceedings of the National Academy of Sciences.
The study specifically examined short-lived greenhouse gases like methane. Methane is the main ingredient in natural gas, and it contributes about a third of modern-day global warming. It’s very powerful, trapping heat 25 times more efficiently than carbon dioxide, but it’s also ephemeral. On average, a molecule of methane is absorbed in the soil or destroyed in the atmosphere 12 years after it is emitted. A molecule of CO₂ can float around for centuries.
Yet the paper shows that the consequences of that methane molecule will last for more than a millennium, causing the the seas to rise higher and higher all the time. That’s because sea-level rise is not only caused by extra water, but by hotter water. As the oceans absorb heat, they expand—and it takes a very long time for this heat to leave.
“The ocean remembers, and that’s really the key message,” says Susan Solomon, an author of the paper and a professor of atmospheric science at the Massachusetts Institute of Technology. “The sea takes a very, very long time to cool down once you’ve heated it up.”
Solomon is a luminary in the field of atmospheric sciences: She led the first Antarctic expedition to study the hole in the ozone layer, and she was among the first to identify how that hole actually formed.
Her and her colleagues’ current finding comes at an unfortunate time: Evidence increasingly suggests that the planet’s methane problem is only getting worse. Last month, an international group of researchers presented a new analysis showing that methane emissions increased after 2007 and began surging in 2014 and 2015. Scientists aren’t yet sure whether melting permafrost, the worldwide growth in natural-gas fracking, or some other source are responsible for the sudden upswing.
The study informs an ongoing discussion among people who care about global warming. Some people advocate for reducing emissions of CO₂, the most abundant greenhouse gas. Carbon dioxide lasts for centuries in the atmosphere, and will be responsible for most of climate change’s ill effects.
But in the short term, carbon dioxide will be aided by “short-lived greenhouse gases,” like methane, nitrous oxide, and the synthetic chemicals called halocarbons. These don’t last longer than a century in the atmosphere, but they can trap much more heat than CO₂. Some think we should tackle them first.
“Our study shows we need to mitigate both as soon as possible. There are no trade-offs,” says Kirsten Zickfeld, an author of the new paper and a professor at Simon Fraser University.
She cited recent research that showed that the heat trapped by gases like methane lasted far longer than 10 years. “There’s this misconception that as we stop emitting these gases, the climate effects will actually go away,” she told me. But that’s not true. Short-lived greenhouse gases, she says, “must be mitigated as soon as possible if future warming and sea-level rise are to be mitigated.”
In their study, Solomon, Zickfeld, and their co-author Dan Gilford projected what would happen if methane emissions accelerated to 2050, and then dropped off entirely. They found that though much of the methane had left the atmosphere relatively quickly, its trapped heat was still causing inches of sea-level rise in 2900.
If emissions of carbon dioxide, nitrous oxide, and methane are all allowed to accelerate to 2050, they could cause three feet of sea-level rise by 2900 through thermal expansion alone. Though they ended their model that year, it showed that the seas would still be rising.
They also ran a similar experiment examining what would happen if the Montreal Protocol did not exist. The Montreal Protocol is a 1980s-era international environmental treaty that restricted the use of some halocarbons, the chemicals causing the hole in the ozone layer. Halocarbons are short-lived, but they trapped a lot of heat in the atmosphere. The authors show that the world avoided much higher sea levels by passing the Montreal Protocol.
For Zickfeld, the study also suggests that it’s risky to plan on removing carbon dioxide in the future. Most UN climate projections already anticipate that the world will develop and use “negative-emissions technologies” at some point in the future—that is, some technology that can scrub carbon from the air.
“What our study shows is that even if we were able to successfully develop these technologies, they won’t allow us to undo sea-level rise,” she told me. Sucking CO₂ or methane from the air may reduce global warming, but some sea-level rise will already be baked in.
“I think this paper will be an eye-opener for policymakers in showing that this ‘short-lived’ perspective does not apply to sea-level,” says Peter Clark, a professor of geophysics at Oregon State University. Clark was a lead author of the sea-level section of the UN’s 2013 assessment report on climate science. He was not involved in this paper.
“As with CO2, the sooner we reduce [short-lived greenhouse-gas] emissions, the less the amount of sea-level rise there will be. This is thus another example of how our actions now as well as in the future are committing the Earth to changes that will have long-lasting impacts,” Clark added in an email.
Kevin Trenberth, a climate analyst at the U.S. National Center for Atmospheric Research, and a lead author of two UN assessment reports, said that “short-lived” has always been a misnomer for these greenhouse gases.
“The short life of some [greenhouse gases] is irrelevant because it is the integrated accumulated effects” that matter, he said in an email. “But the community that this paper is directed toward does not deal with [...] energy budgets. The paper is likely to be new and useful to that community, and perhaps to the policy community.”
It depends which policy community you’re talking about though, as the EPA may soon surrender the ability to legally regulate any methane emissions at all. Since November 8, Congressional Republicans have indicated they want to repeal the Obama administration’s set of environmental protections meant to reduce methane emissions. If they do so under a law called the Congressional Review Act, they will essentially strip the EPA of its ability to regulate methane in any way.
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Computer programming is an art and science of writing programs. A program is nothing but a set of instructions for computer to perform some tasks. The computer programming instruction are written using a programming language.
The programming is an art because you must beautiful, neat and clear programs. Your computer codes should be easy to understand and full of comments so that others can understand a piece of code in your program.
The science part of a computer program has do with choice of a suitable language, algorithms applied, efficient implementation of code and less number of codes. A short and concise program can solve a computer-based problem in less time than a large and complex program that solve then same problem.
Programming Language Tutorials
In this section, you will find links to various tutorial pages. You can go to a specific programming language page and starting our tutorials. You will also find example pages for each programming language, so that you can practice the example projects and programs.
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Asteroids may have delivered water to early Earth An asteroid impact can create glass and melted rock, which can trap water vapor. The finding boosts the idea that asteroids brought water to the early Earth. ZLOVE/ISTOCKPHOTO / Article by LISA GROSSMAN Click here to read the full story.
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Science may help keep a ballerina on her toes. MAVKATE/ISTOCKPHOTO / Article by BETHANY BROOKSHIRE These are a ballerina’s pointe shoes. A dancer will go through many pairs, but one teen used a science fair project to figure out how to save money — and a lot of shoes. Click here to read the full story.
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Swift Creek Elementary School is our Spotlight School of the Week GRADE: 5th Grade PROGRAM: Energy Matters Scientist: Heather Fisher Scientist Sarah and I got to end our week with the fifth graders at Swift Creek Elementary School for Energy Matters. I could tell the students had been studying energy and heat transfer as we went over the three types…
Creekside Elementary School is our Spotlight School of the Week GRADE: 3rd Grade PROGRAM: Skin N Bones Scientist: Davis Tate I got to spend two wonderful days teaching all about systems of the body with Creekside 3rd Graders! This trip was especially fun, because this was my second trip to Creekside this year! As Science Fun Scientists, one thing we…
Durant Road Elementary School is our Spotlight School of the Week GRADE: Kindergarten PROGRAM: Animal Detectives Scientist: Craig Kwiatkowski I had the pleasure of spending my Thursday at Durant Road last week and the kindergartners were such an amazing group. They requested Animal Detectives, which is a program that looks at all sorts of animals and how they similar and… | <urn:uuid:7124fd17-474e-4669-8cf8-a7846c1f73af> | 2.578125 | 448 | Content Listing | Science & Tech. | 41.502656 | 95,621,613 |
The glider on the ocean surface before it descends to begin a mission. (Photo courtesy Mark Baumgartner, Woods Hole Oceanographic Institution)
Mark Baumgartner checks computer data during 2005 field studies. (Photo by Amy Nevala, Woods Hole Oceanographic Institution)
First passive recordings from ocean gliders provide insight into whale behavior for some endangered species
Like robots of the deep, autonomous underwater vehicles, or AUVs, are growing in number and use in the oceans to perform scientific missions ranging from monitoring climate change to mapping the deep sea floor and surveying ancient shipwrecks. Another use for these versatile platforms has now been found: monitoring the lives of whales.
Marine mammals are major predators in the ocean, but little is known about many of them and how changing ocean conditions affect their distribution. Traditional ship or aerial surveys rely on human observers to detect marine mammals, but these observations are limited to daylight hours and periods of calm seas and good visibility. As a result, these surveys are time-consuming, inefficient, and expensive. Marine mammals can also be detected by passively listening for their vocalizations. Passive acoustic monitoring of marine mammals is unaffected by weather, but most applications to date have involved moored or fixed recorders that can assess only when marine mammals appear in a single location.
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....
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The animation highlights the movement in the area between September 2006 and October 2007. The Pine Island Glacier is visible stretching from the right of the image to the centre. The tongue of Pine Island is shown moving inland between September 2006 and March 2007. Between April and May 2007, the detached iceberg in front of Pine Island moves significantly. Also in May 2007, a crack in Pine Island becomes visible. By October, the new iceberg has completely broken away.
Several different processes can cause an iceberg to form, or ‘calve’, such as action from winds and waves, the ice shelf grows too large to support part of itself or a collision with an older iceberg. Since Pine Island Glacier was already floating before it calved, it will not cause any rise in the world sea level.
Iceberg calving like this occurs in Antarctica each year and is part of the natural lifecycle of the ice sheet. A 34-year long study of the glacier has shown that a large iceberg breaks off roughly every 5-10 years. The last event was in 2001.
Pine Island – the largest glacier in the West Antarctic Ice Sheet (WAIS) – is of great interest to scientists because it transports ice from the deep interior of the WAIS to the ocean and its flow rate has accelerated over the past 15 years.
The Pine Island Glacier is up to 2500 m thick with a bedrock over 1500 m below sea level and comprises 10 percent of the WAIS. According to a study by scientists at the British Antarctic Survey (BAS) and University College London (UCL) using ESA's ERS satellite data, a loss of 31-cubic km of ice from the WAIS’s interior from 1992 to 2001 was pinpointed to the Pine Island Glacier.
The thinning caused the glacier to retreat by over 5 km inland, supporting the argument that small changes at the coast of the Antarctic continent - such as the effects of global warning - may be transmitted rapidly inland leading to an acceleration of sea level rise.
Although these long-term regional changes are a cause for concern, the present iceberg calving event does not in itself signal a significant change in the WAIS. Over the last 15 years, the glacier front has advanced seawards at a rate of 3 km/year, so the calving of a 20 km-wide iceberg has simply shifted the glacier front back close to where it was after the last calving event in 2001.
The new iceberg was spotted by scientists at BAS while studying satellite images collected from Envisat using the Polar View monitoring programme. Since 2006, ESA has supported Polar View, a satellite remote-sensing programme funded through the Global Monitoring for Environment and Security (GMES) Service Element (GSE) that focuses on the Arctic and the Antarctic.
GMES responds to Europe’s needs for geo-spatial information services by bringing together the capacity of Europe to collect and manage data and information on the environment and civil security, for the benefit of European citizens. As the main partner to the European Commission in GMES, ESA is the implementing agency for the GMES Space Component, which will fulfil the space-based observation requirements in response to European policy priorities.
The GSE has been preparing user organisations in Europe and worldwide for GMES by enabling them to receive and evaluate information services derived from existing Earth Observation (EO) satellites since 2002.
ASAR acquired these images working in Wide Swath Mode (WSM), providing spatial resolution of 150 metres. ASAR can pierce through clouds and local darkness and is capable of differentiating between different types of ice.
Mariangela D'Acunto | alfa
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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Investigating how species coped with past environmental changes informs how modern species might face human-induced global changes, notably via the study of historical extinction, a dominant feature that has shaped current biodiversity patterns. The genus Bombus, which comprises 250 mostly cold-adapted species, is an iconic insect group sensitive to current global changes. Through a combination of habitat loss, pathogens and climate change, bumblebees have experienced major population declines, and several species are threatened with extinction. Using a time-calibrated tree of Bombus, we analyse their diversification dynamics and test hypotheses about the role of extinction during major environmental changes in their evolutionary history. These analyses support a history of fluctuating species dynamics with two periods of historical species loss in bumblebees. Dating estimates gauge that one of these events started after the middle Miocene climatic optimum and one during the early Pliocene. Both periods are coincident with global climate change that may have extirpated Bombus species. Interestingly, bumblebees experienced high diversification rates during the Plio-Pleistocene glaciations. We also found evidence for a major species loss in the past one million years that may be continuing today.
Mendeley saves you time finding and organizing research
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This Is Your Brain on Nanotubes
Carbon nanotubes can send electrical signals to neurons and are being developed for retinal implants.
Carbon nanotubes – incredibly strong, electrically conductive, hollow molecules of carbon about a nanometer in diameter – have for more than a decade been prized by materials scientists. They’ve added them to batteries to increase their surface area and are developing light-emitting nanotubes for telecommunications.
Now University of Texas researchers have demonstrated that mats of single-walled carbon nanotubes can communicate electrical signals to neurons, suggesting that the tubes could be used as an electrical interface between neural prosthetics – devices used to replace damaged or missing nerves – and the body. This is good news for those hoping to use nanotubes to stimulate or replace nerve cells in the eye, brain, and spinal cord.
The Texas researchers grew rat neurons on thick mats of carbon nanotubes seeded on flexible plastic sheets. Instead of treating the mats like a foreign surface, neurons take well to the nanotubes, says Todd Pappas, director of sensory and molecular neuroengineering at the University of Texas Medical Branch, who led the research. The nanotubes absorb an important neural protein and form a roughly textured carpet on which nerves grow readily. When Pappas and colleagues at Rice University sent an electrical charge across the sheet, the neurons responded with an electrical signal of their own, called an action potential, indicating that they got the message.
[For images of nanotubes and neurons click here.]
An example of a neural prosthetic in use is the cochlear implant, which uses electrodes that respond to sound and send electrical signals directly into the brains of people with severe hearing loss. Likewise, neuroscientists are developing retinal prosthetics they hope will restore vision in the blind. The electrical interface in neural prosthetics usually consists of metal electrodes or silicon coated with metal, says Pappas.
If they’re proved safe for use in the body, carbon nanotubes may have advantages over traditional electrodes. Long-term implants can cause inflammation and scarring, because the body treats them like foreign material. In addition to carbon nanotubes’ advantages of strength, flexibility, and conductivity, their surfaces can be covered with molecules that look friendly to cells.
Pappas says researchers would like nanotubes to mimic the kind of support neighboring cells offer one another, although they are “not yet sure what cells want.” Scientists might try attaching molecules that encourage growth and stability, for example. “Surface modifiers need to be chosen so that the cell considers the nanotubes part of its natural [environment],” says Nicholas Kotov, an associate professor of chemical engineering at the University of Michigan.
Kotov is working with Pappas to develop retinal implants using nanomaterials. “Single-wall carbon nanotubes can be thin and compatible with the mechanics [muscle contractions] of the eye,” says Kotov. Macular degeneration, a condition in which the light-sensing cells in the center of the retina break down, is the most common cause of vision loss in people over 65. To treat the disease, Kotov and Pappas hope to replace the light-sensing nerves with a combination of nanoparticles and carbon nanotubes that can sense light, convert it into an electrical signal, and send a message to the nerves that communicate between the eye and the brain. (These nerves remain intact in patients with macular degeneration.) Kotov says his nanoparticles “can even give color resolution.”
But Kotov cautions that research should proceed very slowly to ensure the safety of any nanotube-based prosthetics. Researchers say that while carbon nanotubes appear to be inert and biologically harmless, their effects on the body have not yet been established experimentally (see “Tiny Toxins?”).
Thomas Webster, associate professor of materials science and biomedical engineering at Brown University, is conducting some of the first experiments implanting carbon nanotubes in live animals. Webster and researchers at Yonsei University in Seoul injected a solution of carbon nanotubes and stem cells into stroke-damaged areas of rats’ brains. “Without carbon nanotubes, the problem is that stem cells don’t stay in the hurt area – they migrate into healthy tissue,” says Webster. In his experiments, the nanotubes helped the stem cells stay put, and their rough surfaces and conductivity coaxed the cells to develop into neurons. He says it’s too early to find out “what happens to the materials after they do the job,” though, or whether the nanotubes will have toxic effects in the long term.
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The result is the most precise measurement to date of the ratio of positrons to electrons in cosmic rays. Measurements of this key ratio may eventually provide the world with our first glimpse into dark matter.
The AMS experiment, developed under the leadership of Professor Ting, with support from the U.S. Department of Energy and fifteen other international partners, is the world's most precise detector of cosmic rays. It was constructed at universities around the world and assembled at the European Organization for Nuclear Research (CERN).
"We are very excited with this first result from AMS," said James Siegrist, DOE Associate Director of Science for High Energy Physics. "We look forward to more important results in the future."
"This result is the first step," said Professor Ting, "the beginning of a series of high precision experimental results from the Alpha Magnetic Spectrometer. This shows that a large international particle physics collaboration can work together to do particle physics in space."
The science goals of AMS include the search for dark matter, antimatter, and new physical phenomena. The detector provides high-precision measurements of cosmic ray particle fluxes, their ratios and gamma rays. From the time of its conception in 1994, U.S. support for the AMS experiment has come from DOE's Office of Science, which provided about $50 million in funding over the life of the program.
This first physics result from AMS is based on 18 months of operation, during which time AMS measured 6,800,000 cosmic ray electrons in the energy range of a half-billion to a trillion electron volts, and over 400,000 positrons (positive electrons), the largest number of energetic antimatter particles directly measured from space. The importance of this measurement is that it could eventually provide a "smoking gun" that certain dark matter particles exist and that dark matter particles and antiparticles are annihilating each other in space.
Although the data do not show a "smoking gun" at this time, this first high-precision (~1% error) measurement of the spectrum has interesting features not seen before that future data may help clarify. With additional data in the coming years, AMS has the potential to shed light on dark matter.
AMS was installed on the Space Station on May 19, 2011 after having been brought into orbit on the last flight of NASA's space shuttle Endeavour under the command of Captain Mark Kelly. Within only hours of its installation on the exterior of the Space Station, AMS became fully operational, and to date has measured over 30 billion cosmic ray events. Working in close cooperation with NASA astronauts and NASA's Johnson Space Center and Marshall Space Flight Center, AMS has maintained a flawless record of performance in the face of a hostile space environment.
Hundreds of scientists, engineers, technicians and students from all over the world have worked together for over 18 years on the AMS collaboration. The collaboration includes scientists from Europe (Finland, France, Germany, Italy, the Netherlands, Portugal, Spain, Switzerland, Romania, Russia, Turkey), Asia (China, Korea, Taiwan), and North America (Mexico and the United States).
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, please visit science.energy.gov.
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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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16.07.2018 | Agricultural and Forestry Science | <urn:uuid:a9fc95da-cab1-435e-825c-011003d863d4> | 3.40625 | 1,346 | Content Listing | Science & Tech. | 39.906275 | 95,621,693 |
Human activity has several detrimental effects on the environment. The use of chemicals can damage fragile ecosystems, the garbage we produce pollutes land and water and production of the energy we use results in harmful emissions that contribute to climate change. Reversing these effects and restoring the environment is a complicated process comprised of various efforts that differ in different places and circumstances. Active restoration of the environment includes small community efforts, such as planting trees in the backyard, and large-scale efforts, such as restoring the Louisiana bayou ecosystem after Hurricane Katrina.
The U.S. government and state of Florida have invested more than $10 billion in a 35-year plan to restore the Everglades. These efforts focus on managing the delivery of freshwater to the area, to reverse the degradation caused by human activities. When the Deepwater Horizon offshore drilling rig sank to the ocean floor in 2010, a massive oil spill damaged the environment in the Gulf of Mexico. Water was contaminated, wildlife was killed, and restoring that environment involved much more than just cleaning up the oil. It took a lot of manpower to restore the area’s river banks and replant wetlands. It does not take a disaster to damage a riparian environment. On a smaller-scale, efforts to restore this type of environment include planting vegetation on stream banks to prevent erosion, filter pollutants before they reach the water and provide cover for fish and other wildlife. Several groups work to restore watershed habitat, so local volunteer opportunities are easy to find. For example, in the Pacific Northwest, Streamkeepers works to restore trout and salmon habitat by adding character, in the form of fallen trees and riparian vegetation, to spawning streams damaged by logging practices.
Logging is one of the most significant threats to forest ecosystems. Aggressive replanting efforts help slowly restore trees to the forest, but other actions are necessary to return the forest to its natural state. These efforts include leaving dead trees to rot and enrich the soil system and encouraging the growth of several plant species. Recreationists can help restore forests by staying on established trails and packing out garbage. Forests are also threatened by the development of commercial and agricultural space. In developing tropical countries, forests are cut down to make room for farms, but groups like the Union of Concerned Scientists are working to intensify crop production on existing farmland to reduce the need for forest restoration efforts.
Grasslands are rapidly disappearing throughout the United States, but several groups are working to restore this ecosystem. In New York, the U.S. Fish and Wildlife Service is restoring grassland habitat in an effort to restore populations of the birds that nest in this ecosystem. They mow down woody vegetation, so that it no longer competes for space and resources with native grass species. Then, they reseed the area with a variety of native grasses.
Reduce the Need for Restoration
One of the best ways to contribute to environmental restoration is to help reduce the need for it in the first place. Recycling materials, such as paper and plastic, will reduce the harvest of the raw materials used to create these products, such as trees and petroleum. It is possible to save more petroleum and reduce emissions that are harmful to the environment by walking, riding a bike or carpooling whenever possible. Conserving energy by turning off lights and turning down the heat will also help reduce harmful emissions, such as the sulfur emitted when coal and oil are burned; sulfur emissions contribute to the formation of acid rain, which further degrades the environment, according to the U.S. Environmental Protection Agency. | <urn:uuid:ef0115da-87bd-48a0-8a88-97649bbd1a9e> | 4.1875 | 718 | Knowledge Article | Science & Tech. | 31.943717 | 95,621,703 |
Electrical properties of a membrane
The simplest representation of a piece of nerve membrane is a simple RC– circuit as shown in Figure 1. The capacitance of a typical membrane, Cm arises due to the fact that there are layers of conductive and nonconductive (lipids) media. The capacitance of a typical patch of membrane is That is the membrane capacitance is measured in terms of the area of the membrane. The larger the area, the larger the capacitance. Since we will be doing most measurements in microns but most constants are in centimetres, the conversion factor is 104 microns per centimeter. The actual capacitance is then CMA where A is the area of the membrane patch. Thus, a spherical cell which is 20 microns in diameter has a total capacitance of
Figure 1: Passive Membrane Model
The membrane also has an associated resistance. As you might guess, the smaller the patch of membrane, the larger is the resistance. The resistance of a typical patch of membrane, RM is so that for our sphere, the actual resistance is Rm=RM/ A or
There are two main points to emphasize:
(i) Associated with any membrane are certain material constants that are independent of the shape of the membrane,
(ii) the actual electrical properties of a membrane depend on its geometry.
where is called the membrane time constant. It is independent of geometry. For our present choice of parameters, The true membrane resistance is difficult to measure since electrodes will puncture the membrane and thus decrease the apparent resistivity. This simple equation is called a one-compartment model for a passive membrane. In general, as we will see, all neural models are made up of pieces just like this and ultimately so are connectionist models that can be derived from these biophysical models. This is the EVE of GENESIS!
The solution to (4) is easy:
where V(0) is the initial voltage.
We could apply a steady current to this membrane as well. Typically, currents are measured in terms of the area of membrane stimulated or current density. The units are typically microamperes per centimeter. This is convenient since one micro-farad times one milli-volt per one milli-second gives one micro-ampere. Positive currents are inward relative to the cell and are called depolarizing while negative currents which are outward relative to the cell are called hyperpolarizing. Suppose we take Vm=-70mV and apply a step of current to our spherical cell. Let’s apply . What is the voltage as a function of time? The equation is
Thus the voltage rises or falls to a new value dependent on the current density. The current, where I is the current density. Note that the final value of the potential is dependent on the current density and not the actual geometry of the cell since the final potential is
For our present example, the steady state voltage is
Note the factor of 1000 is necessary to convert to millivolts.
- Calculate Rm and Cm for a cylindrical cell with diameter of 10 microns and length of 50 microns. Ignore the area at the ends of the cylinder.
- How much current is needed to raise the potential to -55 mV in the spherical cell example above?
- Suppose that RM is . What is the time constant of the membrane.
- Suppose that the spherical cell above is initially at rest. Write the equation for the voltage as a function of time if the current is stepped up to 10 for 20 msec and then set to 0 again. (HINT: Use (6) twice, once for the time when the stimulus is on. Then again, using the voltage at the end of the stimulus as initial voltage.) Sketch the voltage response to this current pulse.
Video Lecture on
“Resting Membrane potential and electrical properties of the cell” | <urn:uuid:345e217a-094c-425e-bf2d-15a72774894c> | 3.75 | 810 | Truncated | Science & Tech. | 43.736243 | 95,621,706 |
Everybody knows that sliding on ice or snow, is much easier than sliding on most other surfaces. But why is the ice surface slippery? This question has engaged scientists for more than a century and continues to be subject of debate. Researchers from AMOLF, the University of Amsterdam and the Max Planck Institute for Polymer Research (MPI-P) in Mainz, have now shown that the slipperiness of ice is a consequence of the ease with which the topmost water molecules can roll over the ice surface.
Winter sports such as skiing, speed skating, figure skating, and curling require the slippery surfaces of ice and snow. While the fact that the ice surface is slippery is widely acknowledged, it is far from being completely understood.
In 1886 John Joly, an Irish physicist, offered the first scientific explanation for low friction on ice; when an object - i.e. an ice skate - touches the ice surface the local contact pressure is so high that the ice melts thereby creating a liquid water layer that lubricates the sliding.
The current consensus is that although liquid water at the ice surface does reduce sliding friction on ice, this liquid water is not melted by pressure but by frictional heat produced during sliding.
A team of researchers led by brothers Prof. Daniel Bonn from the University of Amsterdam and Prof. Mischa Bonn from MPI-P, have now demonstrated that friction on ice is more complex than so far assumed.
Through macroscopic friction experiments at temperatures ranging from 0 °C to -100 °C the researchers show that - surprisingly - the ice surface transforms from an extremely slippery surface at typical winter sports temperatures, to a surface with high friction at -100 °C.
To investigate the origin of this temperature-dependent slipperiness, the researchers performed spectroscopic measurements of the state of water molecules at the surface, and compared these with molecular dynamics (MD) simulations.
This combination of experiment and theory reveals that two types of water molecules exist at the ice surface: water molecules that are stuck to the underlying ice (bound by three hydrogen bonds) and mobile water molecules that are bound by only two hydrogen bonds. These mobile water molecules continuously roll over the ice - like tiny spheres - powered by thermal vibrations.
As the temperature increases, the two species of surface molecules are interconverted: the number of mobile water molecules is increased at the expense of water molecules that are fixed to the ice surface. Remarkably, this temperature driven change in the mobility of the topmost water molecules at the ice surface perfectly matches the temperature-dependence of the measured friction force: the larger the mobility at the surface, the lower the friction and vice versa.
The researchers therefore conclude that - rather than a thin layer of liquid water on the ice - the high mobility of the surface water molecules is responsible for the slipperiness of ice.
Although the surface mobility continues to increase all the way up to 0 °C, this is not the ideal temperature for sliding on ice. The experiments show that the friction is in fact minimal at -7 °C; the exact same temperature is imposed at speed skating rinks.
The researchers show that at temperatures between -7 °C and 0 °C, sliding is more difficult because the ice becomes softer, causing the sliding object to dig deeper into the ice.
The results are published in the Journal of Physical Chemistry Letters.
Prof. Daniel Bonn
1090 GL Amsterdam
phone: +31 (0)205255887
Prof. Mischa Bonn
Max Planck Institute for Polymer Research
phone: +49 (0)6131 379 161
Link to publication:
Link to Max Planck Institute for Polymer Research:
Dr. Christian Schneider | Max-Planck-Institut für Polymerforschung
In borophene, boundaries are no barrier
17.07.2018 | Rice University
Research finds new molecular structures in boron-based nanoclusters
13.07.2018 | Brown University
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 | Life Sciences
18.07.2018 | Life Sciences
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Although many people think that California “owns” all the earthquakes, Ohio also has its share of faults. Unlike another earthquake that woke people on another April 18, 102 years ago, this quake was fairly mild.
Two of UC’s earthquake experts have had extensive experiences with earthquakes. Attila Kilinc is a professor in the Department of Geology in the McMicken College of Arts & Sciences and G. A. Rassati is an assistant professor in the Civil and Environmental Engineering Department in UC’s College of Engineering. Rassati just returned from presenting several seminars in Europe on structural engineering.
Rassati was inspired to become a structural engineer specializing in earthquakes after experiencing one as a child in Italy.
“I was four years old when a strong earthquake struck my region in Italy,” says Rassati. “I have a very strong memory of my Dad trying to get me out of my little bed but he couldn’t get to me. Earthquakes have always interested me ever since.” Rassati has studied the structural and seismic effects on infrastructures, especially buildings.
"Unfortunately, the money is drying up for earthquake research. I'm afraid it's going to take another big one to draw attention to that," says Rassati. "And we're overdue."
Q&A with Attila Kilinc
A: Between 1776 and the present, 170 earthquakes have been charted in Ohio of magnitude 2.0 or greater. There have been at least 150 below magnitude 2.0, which averages out to approximately 1½ earthquakes a year. This latest was not a first, severity-wise: Several others measured inbetween 5.3 and 5.4; in 1980, for example, an earthquake in Sharpsburg, Ky., measured 5.2.Q: Can anyone predict a “big one” ever hitting the Midwest?
A: The U.S. Geological Survey says that references to unusual animal behavior before a significant earthquake date to 373 BC in Greece. Kilinc says that for many years, Chinese scientists in particular watched what they called precursors, such as animal behavior and radon in water, in terms of earthquake prediction. None of the signs they were watching for, he adds, showed up in Tangshan, China, on July 28, 1976. That’s the day an estimated 247,000 people died in China’s deadliest earthquake of the 20th century. Its magnitude was 7.8.Q: For those who have been through a major earthquake in California, this has to seem like barely a rumble. Yet, for many Midwesterners, an earthquake can literally rattle the nerves! How seriously should we take such an occurrence and is there any preparation one can make for an earthquake?
A: Residents of any area should always be prepared for earthquakes, tornados, hurricanes and so forth, making logical preparations that are similar no matter the disaster. For example, if there’s a strong earthquake or tornado and electricity is lost, many people’s first reaction is to strike a match so they can see — and can cause an explosion in a gas line. Also, people tend to want to rush out of an area affected by an earthquake. Kilinc, a former California resident who’s been through many temblors in the Bay Area, says that most people are killed “trying to get in or out,” so staying put is important. Little things matter, too, such as not putting dangerous chemicals on upper shelves in a laundry room.Q: Finally: Another widely spread urban legend claims that California will someday fall into the ocean. While that’s not going to happen, how long could it take, as the Pacific Plate moves, before Los Angeles is close to San Francisco?
A: California, Kilinc says, “will never fall into the ocean” because of a boundary called a transform fault. San Francisco will shift south and Los Angeles, north — but it will take a “long, long time” for them to meet. The USGS says that tectonic forces “in this part of the world are driving the Pacific Plate in a north-northwesterly direction with respect to the North American plate at approximately 46 millimeters per year in the San Francisco Bay Area."
Wendy Hart Beckman | EurekAlert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
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
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Physicist Fatima Ebrahimi at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) has published a paper showing that magnetic reconnection -- the process in which magnetic field lines snap together and release energy -- can be triggered by motion in nearby magnetic fields. By running computer simulations, Ebrahimi gathered evidence indicating that the wiggling of atomic particles and magnetic fields within electrically charged gas known as plasma can spark the onset of reconnection, a process that, when it occurs on the sun, can spew plasma into space.
That plasma can eventually interact with magnetic fields surrounding the Earth, endangering communications networks and power systems. In fusion facilities, reconnection can help start and confine the plasma that fuels fusion reactions. This research was funded by the DOE's Office of Science (Fusion Energy Sciences) and was published in the December issue of Physics of Plasmas.
Using a computer code developed by researchers at universities and fusion labs, Ebrahimi simulated plasma circulating within a vessel shaped like a doughnut. The vessel mimicked the doughnut shape of fusion facilities called tokamaks. The simulated facility had an opening in its floor for physicists to inject magnetic field lines that would balloon in the tokamak's interior and initiate the fusion process.
Reconnection occurred in the following way. The field lines forming the balloon created an electric current that produced three-dimensional wiggles and wobbles that pushed the open end of the balloon until it closed. At that point, magnetic reconnection occurred and turned the magnetic balloon into a magnetic bubble called a plasmoid that carries electric current.
Ebrahimi is now expanding that research. She is currently looking into how to harness the current to create and confine a fusion plasma without using a large central magnet called a solenoid.
Different conditions can set off the reconnection process. "If the strength of the field lines associated with the original magnetic balloon is not enough on its own to instigate reconnection," Ebrahimi said, "the secondary magnetic wiggles can amplify the magnetic fields at the reconnection site, triggering the event." She is also investigating the amplification of magnetic fields through these secondary three-dimensional magnetic and fluid wiggles known as the dynamo effect.
These findings on the effect of magnetic fields can have a broad impact. "The analysis and the modeling can help us better understand how the reconnection process that is triggered by magnetic perturbations in plasmas can lead to the detachment of magnetic loops on the surface of the sun, or efficient startup for fusion plasmas," Ebrahimi said.
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...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Life Sciences
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why do objects fall at the same time
This is only the case in a vacuum because there are no air particles, so there is no air resistance; gravity is the
only force acting. You can see it for yourselves with this easy Take one piece of A4 paper and scrunch it up into a ball. Take two pieces of identical A4 paper and scrunch them up together into another ball. Your two paper balls should be of similar size but one twice as heavy as the other. Now drop them from the same height at the same time Б you will see that they hit the ground at the same time! There is still air resistance but its effects are the same for both balls as they are the same size and shape. So itБs like thereБs no air resistance at all! Here are two different ways of explaining this phenomenon. б u Explanation using equations: /u Any object of mass em m /em in a gravitational field (in this case EarthБs) has a strong gravitational force /strong, em F /em, acting on it: em F /em #61; ( em GmM /em ) / em R /em sup 2 /sup where em G /em is the gravitational constant (this number does not change, it is the same throughout the whole universe), em M /em is the mass of the Earth, and em R /em б is the distance between the object and the centre of the Earth.
It is this force which causes objects to fall to the ground in the first place. NewtonБs Second Law states that a strong force /strong acting on an object will cause a change in speed, or strong acceleration /strong, em a /em, of the object: em F /em #61; em ma б б б б (Very important equation) /em Therefore, the gravitational force will cause the object to accelerate towards the Earth. To find a formula for this acceleration, we combine the two equations for em F /em above: em ma /em #61; ( em GmM /em ) / em R /em sup 2 /sup Then we can divide through by em m /em to get: em a /em #61; ( em GM /em ) / em R /em sup 2 /sup As we can see, em m /em does strong not /strong appear in this formula, meaning that the acceleration of an object in free-fall strong does not depend on its mass /strong. б u БWordyБ explanation: /u Gravity exerts a greater force on a heavy object than on a light object which is what you would expect. em So why donБt heavy objects fall faster? /em The effect of this greater force on the acceleration of the object is cancelled out by the greater mass of the object.
To help us understand this, letБs consider the following analogy. Imagine that you have to pull two boxes across a room; one box is twice as heavy as the other. In order to pull them at the same speed you need to pull the heavier box with twice as much force. Gravity pulling objects to the ground is like you pulling boxes across a room. Gravity needs to exert more force on heavier objects to make them fall as quickly as lighter objects. , it was stated that the acceleration of a free-falling object (on earth) is 9. 8 m/s/s.
This value (known as the acceleration of gravity) is the same for all free-falling objects regardless of how long they have been falling, or whether they were initially dropped from rest or thrown up into the air. Yet the questions are often asked doesn t a more massive object accelerate at a greater rate than a less massive object? Wouldn t an elephant free-fall faster than a mouse? This question is a reasonable inquiry that is probably based in part upon personal observations made of falling objects in the physical world. After all, nearly everyone has observed the difference in the rate of fall of a single piece of paper (or similar object) and a textbook. The two objects clearly travel to the ground at different rates - with the more massive book falling faster. The answer to the question (doesn t a more massive object accelerate at a greater rate than a less massive object? ) is absolutely not!
That is, absolutely not if we are considering the specific type of falling motion known as free-fall. Free-fall is the motion of objects that move under the sole influence of gravity; free-falling objects do not encounter air resistance. More massive objects will only fall faster if there is an appreciable amount of air resistance present. The actual explanation of why all objects accelerate at the same rate involves the concepts of force and mass. The details will be discussed in. At that time, you will learn that the acceleration of an object is directly proportional to force and inversely proportional to mass. Increasing force tends to increase acceleration while increasing mass tends to decrease acceleration. Thus, the greater force on more massive objects is offset by the inverse influence of greater mass. Subsequently, all objects free fall at the same rate of acceleration, regardless of their mass.
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Singapore: Rapidly warming ocean temperatures in some parts of the world could be pushing some fish species to the limit, stunting their growth, increasing stress and raising the risk of death, a study shows.
An Australian study, published on Monday in the journal Nature Climate Change, focused on the long-lived fish species called the banded morwong in the Tasman Sea, between Australia and New Zealand.
Scientists, using long-term and current data, found that the morwong`s growth in some areas has been slowed by a jump in sea surface temperatures of nearly 2 degrees Celsius over the past 60 years in the Tasman Sea, one of the most rapid increases in the southern hemisphere`s oceans.
The results have implications for other fish species, including commercial fisheries, as seas heat up and become more acidic, affecting coral reefs and multi-billion dollar fisheries dependent on them.
Generally, cold-blooded animals respond to warming conditions by boosting growth rates as temperatures rise, said marine ecologist Ron Thresher of Australia`s state-backed research body the CSIRO. But there was a limit.
"By examining growth across a range that species inhabit, we found evidence of both slowing growth and increased physiological stress as higher temperatures impose a higher metabolic cost on fish at the warm edge of the range," Thresher told Reuters from Hobart, Tasmania.
"A lot of commercial fish don`t move very much," said Thresher, a co-author of the study with colleagues from the University of Tasmania`s Institute for Marine and Antarctic Studies.
"They tend to return to the same spawning grounds or they live on the same reefs. And those are the ones that are going to be most affected," he said. This was particularly so for long-lived fish and those that live near the shore and at shallow depths. The banded morwong can live nearly 100 years.
Some species, though, such as tuna, are far more mobile and are moving further south into cooler waters.
Thresher and his colleagues used data on the morwong going back to 1910 that focused on bony structures called otoliths. These have annual growth rings that are similar to growth rings in trees.
Studying data from samples of the species in the Tasman Sea, they found increased growth for populations in the middle of the species` range in Australian waters where temperatures have increased, but are still relatively cool.
But growth slowed with rising temperatures at the warmer northern edge of the range around New Zealand.
The scientists found that the drop in growth could be related to higher stress levels from rising temperatures, increased oxygen consumption and a drop in the ability to swim for long periods. | <urn:uuid:402b7bd6-3e63-47c3-bb71-554d4e1db939> | 3.53125 | 551 | News Article | Science & Tech. | 40.272 | 95,621,723 |
Reefs containing more than 600 kilograms per hectare of fish biomass should be conservation priorities
A new study by WCS (Wildlife Conservation Society) has found that coral reef diversity 'hotspots' in the southwestern Indian Ocean rely more on the biomass of fish than where they are located, a conclusion that has major implications for management decisions to protect coral reef ecosystems.
Using data gathered over a 12-year period from nearly 270 coral reefs across the southwestern Indian Ocean, the WCS study found that the highest conservation priorities in the region should be reef systems where fish biomass exceeds 600 kilograms per hectare. This finding conflicts with a common conservation and management policy that emphasizes the geographical location and physical factors that are often associated with reef diversity.
The study--authored by Dr. Tim McClanahan of WCS (Wildlife Conservation Society)--appears in the latest edition of the Journal of Biogeography.
Click here for a link to the study: http://onlinelibrary.
"While geography has often been the main factor that conservation policy has used to establish protected areas, this study shows that protecting fish biomass should be the priority and this can be done with improved fisheries management," said McClanahan, a Senior Conservationist for WCS. "A hotspot is not a permanent feature and can be lost if the fish and the habitat are not protected."
Experts agree that fishing is a primary cause in the degradation of coral reefs, and needs to be better managed but what is more controversial is the various roles of protected areas or fisheries restrictions. Protecting regions containing threatened biodiversity--considered to largely be an attribute of geography-- has created a policy focus on the geographic hotspots. McClanahan found that the hotspot in the Indian Ocean is a real feature but is maintained more by fish biomass and habitat than by the geographic location. This means that fish biomass and habitat are the most influential factors and should be used to guide management decisions rather than location.
McClanahan's study of 266 sites in seven countries of the southwestern Indian Ocean measured numbers of fish species while simultaneously collecting information on the abundance of corals and algae, depth, geographical location, and the types of fisheries management. This allowed him to compare the importance of each of these factors.
The results support previous studies identifying the Mozambique Channel as a center of species richness in the southwestern Indian Ocean. However, sites in this region with low fish biomass also lacked full diversity, and being in this hotspot center alone did not ensure high diversity. Stronger correlations were found between biomass and local factors such as restrictions on fishing along with coral cover and water depth. The latitude and longitude were significant but found to contribute the least to the variation in numbers of species - a finding that challenges common conservation wisdom.
The study also reveals that protected areas that lacked regular and strong enforcement of fishing bans - classified as 'low compliance' fisheries closures - had nearly as low numbers of fish species as reefs that were regularly fished. The low compliance category included 50 of the 104 reefs included in the study. McClanahan added: "Having fishing restrictions is better than closing reefs to fishing if the closure rules are not followed, which was common and found for nearly half of the studied closures."
"The Southwest Indian Ocean is a globally important marine biodiversity hotspot. Unfortunately, this study shows that many protected areas are not doing a good job at protecting fish diversity, a shortcoming that threatens some of the world's most important coral reefs," said Dr. Caleb McClennen, Executive Director of the Marine Program. "While these ecosystems are complex, it is clear we need to do at a minimum two things very well to save the world's coral reefs: strictly enforce established marine protected areas, and; outside these areas, increase the sustainability of fishing practices to increase biomass."
The projects that lead to the compilation of the large data set were supported by the John D. and Catherine T. MacArthur Foundation, The Tiffany & Co. Foundation, and the Western Indian Ocean Marine Science Association (WIOMSA).
John Delaney | 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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12.07.2018 | Event News
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19.07.2018 | Earth Sciences
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What are the units of specific gravity? Assuming that the density of water is 0.997 g.mL^-1 and the specific gravity of gold is 19.28 what is the density of gold in g.mL^-1? In pounds per cubic foot?
my attempt: no units for specific gravity. Density of gold in g.ml^-1 = 19.2 g/mL^-1 I have no idea how to convert to pounds per cubic foot?
4. The mass of the earth is 6.1 x 10^27 g and the radius is 6.4 x 10^6 m. What is the average density of the earth in g.mL^-1? Hint the volume of a sphere is 4/3 pie r^3 where r is the radius of the sphere.
2.6 x 10^19 g/ml^-1
5. The mass of a neutron is 1.675 X 10^-24 g. The radius is about 10^-15 m. What is the density of a neutron in g.mL-1? What assumption is being made about the structure of the neutron in this calculation?
my attempt: 4.2 x 10^ -45
assume the structure is a sphere?
Suppose you have a metal with a small volume (0.5mL) and a metal with a large volume (5.0mL). Which should give a higher percentage error if we use the water immersion method? explain.
my attempt: i would think less water would give a higher percentage error but not sure of the reasoning my guess the water not covering the metal throwing off the accuracy?© BrainMass Inc. brainmass.com July 20, 2018, 6:56 am ad1c9bdddf
The solution contains an attachment with the solution and step-by-step procedure to the given problems. | <urn:uuid:be3a8aee-fb90-4bef-88bf-08631e8046dd> | 2.921875 | 388 | Q&A Forum | Science & Tech. | 100.54855 | 95,621,737 |
Elon Musk has presented a study with details on how SpaceX plans to establish a permanent human settlement on Mars. The research has been published in New Space, and expands on the plans introduced by Elon Musk at the International Aeronautical Congress (IAC) in Guadalajara, Mexico in September 2016.
During the IAC presentation, Elon Musk stated that the reason he was acquiring assets through other ventures was for the sole purpose of making human life interplanetary. Musk however noted that it was a massive task, and welcomed co-operation from other private spaceflight companies towards establishing a permanent human presence on Mars.
Private spaceflight companies are an important component of NASA’s Journey to Mars, a major undertaking that requires the US space agency to use every resource at its disposal. The space telescopes, new launch systems, space stations, commercial cargo craft, and a bunch of orbiters and landers will all play a role.
Mars is an object of interest of colonisation because of how suitable the conditions on the Red Planet are for hosting humans. A study from Harvard shows that four billion years ago, Methane in the atmosphere of Mars made the local conditions warm enough to support life. Data from the Curiosity rover shows that the Gale crater on Mars had a lake with conditions suitable for life, about three and a half billion years ago.
Mars is also the best candidate for a permanent settlement, by process of elimination, considering how unsuitable the other options are. The weather on Venus is too violent, and Mercury is too close to the Sun. The Moon, and the satellites of the Gas Giants are options. However, the Moon does not have nearly as much resources as Mars, and the Gas Giants are much farther away than Mars. Mars is the first stepping stone for making humans an interplanetary species.
SpaceX and NASA are scouting Mars for a landing site to seed of a potential permanent settlement. One of the criteria for selecting a landing site is easy access to large quantities of ice, preferably closer to the surface. Another important criteria is that the site should be close to the equator, for better power generation through solar panels.
The plans are not in the realm of science fiction any more. The chain of events leading up to future manned missions to Mars has already began. In October 2016, just a few months before the end of his term, the then President of the United States outlined NASA plans to send humans to Mars by 2030 in a story for CNN. “We have set a clear goal vital to the next chapter of America’s story in space: sending humans to Mars by the 2030s and returning them safely to Earth, with the ultimate ambition to one day remain there for an extended time,” he wrote.
In March 2017, the US Congress passed a bill known as the Nasa Transition Authorisation Act of 2017 that approved of a manned mission by NASA to Mars by 2033. The President of the United States, Donald Trump, approved the bill a few days later. One of the key points in the bill was that NASA would have to look into a “potential human habitation on another celestial body and a thriving space economy in the 21st Century.”
NASA: Journey to Mars
The first step for NASA is to successfully undertake a manned mission to Mars, where the early explorers will stay on the planet for a short period and then return to Earth. A one way trip to Mars would take about a year and a half if current technologies are used. By the year 2030, this period is expected to come down to about six months.
The pioneers cannot possibly take everything they require on the mission, so NASA is building the technologies needed for using the resources available on the red planet itself. The approach is called in situ resource utilisation (ISRU). The equipment for extracting the raw materials will have to work under the harsh and alien conditions on Mars.
The soil and atmosphere are different from the Earth, so the equipment for the mining of materials on the surface will have to be adapted to the Martian conditions. Additionally, the gravity on the Red Planet is sixty two percent lower than that on Earth. The excavators will have to work in the low gravity environment. One of the options that NASA is exploring for mining on Mars is the Regolith Advanced Surface Systems Operations Robot (RASSOR).
Food will be another requirement for supporting a manned mission to Mars. The International Space Station has two VEGGIE facilities where experiments are being conducted on growing plants in low gravity environments. NASA will have to figure out what kind of nutrients need to be added to the soil on Mars, to allow crops to grow. Even high school students are helping out studying the suitable kind of crops to grown in space, by just identifying the crops that grow best in the artificial conditions. NASA has even designed inflatable greenhouses for future manned missions to the Moon and Mars.
Shelter is another important consideration for the manned mission. Taking along all the equipment needed for housing the humans, the equipment, the farms and the laboratories would be too expensive. A lot of material would be required because of the lethal amounts of radiation on the Martian surface, as well as the constant bombardment by micrometeorites. The current approach by NASA involves building structures from 3D printers that use the regolith on the Martian surface.
Researchers from the Northwestern University in the US have developed a 3D printing technique that uses the kind of soil found on Mars, to create a pliant and flexible material similar to rubber. The material can be cut, folded, rolled or otherwise shaped in a number of different ways. The technology can be used to make tools, or print interlocking blocks similar to LEGO bricks, to be used for constructing buildings.
One of the ideas proposed by Stanford and NASA engineers is to combine the regolith available on the Martian surface, with a protein derived from bovine blood. The component is easily available as a by-product from slaughterhouses, and practically becomes glue when mixed with soil. To make the component available on Mars, the idea is to create factories of organisms genetically engineered to produce the protein binder. However, there is an alternative to bio-concrete.
The iron oxide on the surface of Mars, that gives it the characteristic red appearance, has a property that can be very useful for humans. The iron oxide acts as a binding agent, and allows for the Martian regolith to be compacted into bricks, without the need of an Oven. The only thing necessary is pressure, there is no requirement to add anything to the soil, or heat it. The resulting bricks are stronger than concrete reinforced with steel.
Any epic space adventure is incomplete without a trash compactor. NASA is building a trash reactor that can convert garbage into fuel, and other resources needed by humans in a space colony, including oxygen and water. Such a trash to gas reactor already exists at the Kennedy Space Center, one of the NASA facilities. Annie Meier, a chemical engineer at the Kennedy Space Center says "There is food waste, there is biological waste, there is packaging waste. Here at Kennedy, we’re working on how to make this waste into useful products, such as methane for fuel."
One of the key part of the plan for going to Mars and beyond is building a permanent space base near the Moon, to act as a gateway for deep space missions. NASA has teamed up with Boeing to develop the plans for such a base, to act as a testbed for emerging technologies needed for pioneering interplanetary missions. NASA even has plans for a year long manned mission to the Moon to prepare for the eventual manned mission to Mars.
One of the studies conducted by NASA suggests an ambitious project to make the conditions on Mars more suitable for human life. The idea is to permanently place an inflatable magnetic dipole at the Sun facing Lagrange point to create a magnetopause that will protect the Red Planet from the ravages of solar wind. Mars once had an atmosphere that has been stripped away by the Sun. The artificial magnetosphere to shield the planet could be the first step in terraforming it.
SpaceX: Making human life interplanetary
While NASA wants to go to Mars for exploration and the advancement of science and technology, for SpaceX and Elon Musk it is a question of survival. If humans do not get to Mars, we are going to die out. The challenge is to reduce the cost of a Mars mission to make it affordable, which means reducing the cost by a factor of five million per cent.
Reusability of the rockets is an important part of bringing down the costs. Another way of brining down costs is to build bigger rockets, deploy tankers in orbit, and regularly shuttle spacecraft between Earth and Mars. The idea is to use every single launch opportunity for an efficient trip to Mars, and make the trips as regular as a subway service on Earth.
The system for achieving this is known as the Interplanetary Transport System. A re-usable booster will deploy colonial ships or tankers into space, and then return to the Earth to be used again. With a lift off mass of 10,500 tons, the ship and booster combined will make the heaviest launch vehicles currently planned.
A Dragon spacecraft to Mars is already being planned as early as 2018, and another one in 2020. These are pathfinding missions, meant to identify suitable landing spots for the first colony ship with humans on board. The first ship will have a propellant plant, to mine the water and carbon dioxide on Mars and convert it into fuel for the spaceships going back to Earth. The first Mars flights are planned to begin by 2023.
Making sure that all the resources available are used optimally is a challenge for closed systems in space, such as a space station. It would be a much bigger challenge to establish that efficiency in a space colony. The eventual aim is to keep sending missions to Mars to build a self sustaining city on the Red Planet. Electricity for the settlement will be provided by an array of solar panels.
A self sustaining colony needs a minimum of 10,00,000 people. This means 5,000 to 10,000 manned missions to Mars, with each ship containing between 100 to 200 people. The spaceships are padded out with entertainment areas and arenas for zero gravity games, to make the travel a bearable experience.
For SpaceX, a permanent settlement on Mars will allow humans to explore even deeper in the solar system. This allows spacecraft to hop from the Earth, to Mars, and beyond. Prime targets include Enceladus and Europa, moons of Jupiter, and Titan, a moon of Saturn. Fuel depots on these moons would allow humans to hop even further.
In the paper published by New Science, Musk writes “You could travel out to the Kuiper Belt, to the Oort cloud. I would not recommend this for interstellar journeys, but this basic system—provided we have filling stations along the way—means full access to the entire greater solar system.”
Boeing: Path to Mars
Boeing is also supporting NASA plans to send a manned mission to Mars by building the architecture to support the vision. In fact, the CEO of Boeing has vowed to beat SpaceX to be the first private spaceflight company to reach Mars. This will not be a colonisation mission, or a pioneering mission. Boeing also has the costs figured out… they plan to simply send tourists. Dennis Muilenburg proclaimed at an event, “I’m convinced the first person to step foot on Mars will arrive there riding a Boeing rocket,” according to a report in Bloomberg.
Apart from the space launch system (SLS) and the Orion spacecraft, which are both in the production stage, Boeing is in the early stages of developing a transit habitat for housing the pioneers on the first mission to Mars. Before the trip to Mars, the hardware and the equipment for the journey will be tested on the International Space Station, as well the gateway for deep space operations in the vicinity of the Moon.
Another craft by Boeing in the early stages of development is a deep space tug. The tug will be useful for docking operations, and moving tankers and spacecraft about in space. The tug will be propelled by a combination of solar electricity captured through panels, and chemicals. Boeing plans to realise the deep space tug and the transit habitat by the early 2030s.
By the late 2030s, Boeing plans to build two spacecraft necessary for regular operations on Mars. The two vehicles in the concept stage are a Mars Lander and a Mars Ascent Vehicle. The Mars Lander has a heat shield which will separate from the craft after entering the atmosphere, allowing the lander to execute a soft propulsive landing. The ascent vehicle will take the lander back into space, and also contains a module similar to the transit habitat, for stays of short duration. The Mars Ascent vehicle can potentially be used as an emergency vehicle for the early travelers to Mars.
For Boeing the entire mission is an undertaking to advance various aspects of the human race. The mission to mars is an opportunity to learn more about the origins of life, perhaps discover new and alien life. We can use the resources on the planet, and the advancement of science and technology will foster economic growth. Most importantly, such a mission will leave a better future for the next generation.
Colonising Mars will be a global effort
As Boeing points out, there are young men and women in schools dreaming about going to the Red Planet. These will probably be the people who realise the technologies necessary, as well as make up the pioneering crew on the first manned missions. Lockheed Martin had recently held a competition for school students, to design a spacecraft for manned Mars missions. Here is the winning entry:
Rick Ambrose, executive vice president for Lockheed Martin Space Systems said, “Our Generation Beyond resources help make STEM learning fun and inspiring. Humanity's next giant leaps in space deeply depend on students at the K-12 level pursuing careers in science and engineering”
Last month, the Ohio State University hosted the Armstrong Space Symposium, which included astronauts from the Apollo Moon missions as well as representatives from leading private spaceflight companies. The discussion centered on how mankind will get to Mars. Apollo 15 astronaut Al Worden, 85 years of age, said that he would not mind volunteering for the Mars mission, "I can sit all day and watch TV and not get bored, send an old man."
Apollo 11 Astronaut Michael Collins said "I don’t think Musk understands the enormity of a Martian mission. It makes Apollo look like child’s play." There were no SpaceX representatives, but Will Pomerantz, Vice President for special projects at Virgin Galactic responded with "All this stuff is harder than anyone thought."
In the New Science paper though, Musk does not hesitate to admit that the mission can fail. Musk writes, “There is a huge amount of risk. It is going to cost a lot. There is a good chance we will not succeed, but we are going to do our best and try to make as much progress as possible”. Musk does provide an explanation for SpaceX undertaking such ambitious schemes – it is to gather more support.
"There are also many people in the private sector who are interested in helping to fund a base on Mars, and perhaps there will be interest on the government sector side to do that too. Ultimately, this is going to be a huge public–private partnership. Right now, we are just trying to make as much progress as we can with the resources that we have available and to keep the ball moving forward. As we show that this is possible and that this dream is real—it is not just a dream, it is something that can be made real—the support will snowball over time."
Ken Davidian, director for research at the Federal Aviation Administration Office of Commercial Space Transportation and a panelist at the Armstrong Space Symposium noted that the importance of the ambitious plans."We’re lucky that we have (people) as ‘irrational’ as Jeff Bezos and Elon Musk that they’re willing to pursue these goals" Todd May, director of NASA’s Marshall Space Flight Center pointed out that going to Mars “is going to take all we got—NASA and the billionaires and the private space agencies. It’s going to take all mankind.”
Massive reusable rockets, 3D printed habitats, crops grown in controlled environments, optimum use of resources, recycling waste to the largest extent possible and efficient use of solar energy, are just some of the scientific and technological advancements needed for colonizing Mars. Establishing a permanent human settlement on the Red Planet may make humans an interplanetary species, but it also holds the promise of making the Earth a better place to live in. | <urn:uuid:1d753037-e4c1-443e-9615-d9f1e7a346ac> | 3.578125 | 3,450 | News Article | Science & Tech. | 45.377761 | 95,621,740 |
The overwhelming majority of genes are represented in two copies in the cells of animals: one is received from the mother, the other – from the father. In many cases, the organism endures with difficulty the damage to one of the copies: a single dose of a gene may be insufficient for normal evolution. However, for some genes a single dose is not simply endurable but also welcome. Such cases deal primarily with the genes that increase life span and stress resistance. Individuals with a single normal copy of such gene (the second copy is desperately spoiled as a result of mutation) live longer and better endure unfavorable conditions. But, the owners of a double dose of the mutant gene are either nonviable or more frequently than others die of some disease such as malignant growth.
Investigation of mutations in stress resistance genes is only possible on models, and the researchers worked with drosophilas. They studied the lgl tumor suppressor gene. Human beings have the gene with the same functions, it is called Hugl-1. If normal copies of the gene are absent in the cells, frequency of cancer occurrence is high. It may seem that such detrimental mutation should be abolished by selection, however, the lgl gene mutations are rather frequently found in the population. Why?
It has turned out that the drosophilas containing one mutant copy and one normal copy of the gene possess increased embryonic survival rate if they develop at stressful temperatures (16 and 29 degrees centigrade). At the temperature of 25 degrees (which is optimal for flies), viability of mutation carriers is slightly lower that the one of owners of the double gene dose. Besides, mutation carries have a longer life span. These useful properties become normally apparent in case if mutation was received from the mother. Apparently, increased viability of flies is being formed in the early embryonic evolution stage and depends on the maternal genotype. Mutation carriers are more stable to viral infections.
Thus, if the gene does not work at all in case of two mutant copies, then probability of cancer development in the organism is high, and a single copy of the gene (in case of one mutant copy) in some way ensures optimal state of the organism in stress conditions.
Cancer development with human beings and animals is a complicated, multi-stag process connected with the loss or damage of certain genes. The drosophila investigations carried out by the Russian researchers help to understand why the mutations that can cause cancer do not disappear from the population but are preserved in it.
Nadezda Markina | alfa
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell 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 | Materials Sciences
20.07.2018 | Physics and Astronomy
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Something similar to this image will be obtained. A kink in the field lines is observed, corresponding to the division of space into two regions: the inner region, close to a circle, enclosed by the kinks, which contains those points of space that already "know" that the charge has stopped, and the outer region, containing the points where the information has not yet arrived. The field lines in the outer region (look at the red arrows) point towards the position where the charge would be found if it had kept moving with the same velocity (which would be the same as the position of the neutral particle, that keeps moving until the simulation is stopped).
A less sharp stop of the charge is shown in the following example.
The result obtained will be similar to that shown in the following figure. A circle centred at the starting point of the charge is plotted in red, and other circle centred at the point where deceleration begins in blue.
Search for an interpretation of the results.
Repeat the previous process but introducing now an acceleration of the charge. To do this, place the slider on the left. The result will be something like that:
Since the particle already had a high velocity, it accelerates up to a velocity very close to the speed of light. The field concentrates in a plane transversal to the direction of the motion of the charge. The field distribution is not radial any more. The radial distribution is therefore a characteristic of charges that move slowly compared to the speed of light. | <urn:uuid:0c6ab74b-235c-4942-9ba0-a457a137da3a> | 3.78125 | 310 | Documentation | Science & Tech. | 48.230653 | 95,621,774 |
Why the ‘Obsession’ with Urban Biodiversity Could Be a Fatal Distraction | KCET
Why the ‘Obsession’ with Urban Biodiversity Could Be a Fatal Distraction
Published as part of an environmental storytelling partnership with the Laboratory for Environmental Narrative Strategies (LENS) at UCLA, with extensive contributions from faculty and MFA students in UCLA’s documentary film program in the School of Theater, Film and Television. The second storyline considers how Los Angeles has inadvertently become a sanctuary city for non-native animal species that are sometimes endangered in their native habitats. Find more Urban Ark stories here.
“They’re here!” We craned and shuffled and peered, and — there they were: maybe six or eight parrots, perched in pairs at the top of a tree in Pasadena’s La Pintoresca Park, lit up by the last few minutes of sunset. But they had not truly arrived. Not yet.
Within a few minutes, there were a hundred parrots in the tree, then hundreds, then hundreds more in all the trees around us. Every branch of every tree for blocks was thick with parrots. The sky darkened faster than the sunset accounted for, as huge flocks of hundreds of birds obscured the San Gabriels in the distance and converged on the trees at the Pasadena intersection of Fair Oaks and Washington Boulevard. And they were all screaming, sharing the day’s gossip with a sound that drowned out the traffic and made us shout at each other: “Ok, they’re here!” And more came, and then they truly were here. Then, they were quiet.
More About Urban Biodiversity
Every day at sunset, Pasadena’s population of red-crowned parrots returns to roost here overnight. It’s an incredible show — Austin has its bat bridge, Seattle has its fish ladder, and Pasadena has its parrot park. The birds are a thrilling example of urban biodiversity. These parrots are endangered in their home range in northeastern Mexico but are thriving here. They are also an opportunity to experience a concept not yet as widespread as biodiversity: “bioabundance.” The term refers not to the number of species in an area but, more simply, to the number of individual creatures. There’s a big difference between a species being present and a species being abundant: a lone bird of a rare species may be an exciting find for birders, but a thousand of a more common species become part of the landscape, in terms of both ecology and experience. Experiences of bioabundance can be uniquely enriching, even overwhelming. Unfortunately, they may be harder and harder to find.
Several pieces in this series explore the ways in which scientists have come to appreciate and catalogue the biodiversity of cities like Los Angeles. Citizen science efforts, such as the Natural History Museum’s BioSCAN project, have revealed the incredible diversity of undiscovered species waiting to be found in urban areas. Another example is the city’s Sustainable City pLAn, which outlines the L.A.’s goal to “protect and support biodiversity.” Policies designed to support biodiversity — including expanding the city’s green spaces and developing non-toxic alternatives to pesticides — will likely lead to increased bioabundance as well.
Recently, though, some environmental thinkers have argued that adopting “biodiversity” as our standard measure for the health of a natural system can distract us from losses that drastically impoverish ecosystems even if they don’t kill species. Simon Barnes worries about the “crashing numbers of ordinary everyday creatures” that go unnoticed when we focus on the plight of rarer endangered species. Hugh Warwick has suggested that our “obsession with biodiversity” leads us to ignore evidence of catastrophic drops in the population of, for example, insects — citing a study showing a decline of insect biomass in Germany of 80 percent over less than 25 years.
Other unflashy creatures are suffering as well. A 2010 study suggested that the number of microscopic phytoplankton in the world’s oceans has declined over 40 percent since 1950. These tiny plants are the ultimate source of food energy for every animal in the ocean. They also help convert carbon dioxide in the atmosphere into oxygen, so their decline will likely contribute to global warming — and global warming, in turn, means less phytoplankton. Even if this cycle never causes plankton species to go extinct, the decline in abundance means a decline in fish, whales, dolphins and other charismatic megafauna we think of when we think of ocean biodiversity:. It also means a decline in the wealth and sustenance that people pull from the sea. In the same fashion, declines in the populations of bees, which pollinate our crops, could have many of the same effects on land.
But beyond the loss of the “ecosystem services” that we depend on, the shrinking number of plants and animals in the world around us — Michael McCarthy calls it “the great thinning” — is also the loss of a certain, remarkable kind of experience. McCarthy’s book “The Moth Snowstorm” is named for a memory from McCarthy’s childhood: when “moths filled the summer nights … in such numbers that they would pack a car’s headlight beams like snowflakes in a blizzard, there would be a veritable snowstorm of moths, and at the end of your journey you would have to wash your windscreen, you would have to sponge away the astounding richness of life.” As in Germany, insect populations in Britain have dropped by over 50 percent since midcentury, and the moth snowstorm is only a memory for people old enough to have lived through the experience. McCarthy describes a version of what marine ecologist Daniel Pauly has called “shifting baseline syndrome”: each generation's understanding of what constitutes a normal natural world is set by their experiences in childhood. And so, if we only measure an ecosystem’s biodiversity, we might miss the lost opportunity to experience what McCarthy calls “astounding richness of life.”
But nostalgia for such experiences remains. Maybe this is why the passenger pigeon is such a popular example of the possibility of de-extinction: when you read people’s descriptions of what it was like to see their flocks, which numbered in the billions and could take hours to pass, it’s hard not to yearn for that kind of biological immensity. Passenger pigeons seem to be a kind of charismatic megaspecies — a symbol for the fragile abundance of the natural world.
Luckily, there are opportunities for experiences like this — at least a little like this — available in California today. Every fall, thousands of Vaux’s swifts migrating south along the West Coast stop over in L.A. for a few nights. Some years, huge flocks have roosted in abandoned chimneys in downtown L.A. (Making sure there are always chimneys for the swifts might be a good application of biophilic design principles.) On the coast in the spring and summer, thousands of six-inch silver fish — grunion — wriggle out of the water in the moonlight to spawn. After wet winters, superblooms drench the desert in color. Santa Monica Bay is home to a booming shark population — although it may be best not to go see that example in person.
And butterflies. One of the most remarkable instances of bioabundance I’ve experienced was at the Pismo Beach monarch grove in November 2017. Monarchs spend their winters here and at other points on the coast to rest. In the gray light of an overcast fall day, they can be hard to see among the leaves of the trees. Until you lean in close, or a gust of wind blows through the grove, and you realize all those shaking leaves are the monarchs, and suddenly the whole grove is shimmering black and orange around you. The monarchs cover the trees and hang from them in long, fluttering strands. There can be hundreds of thousands at once; it’s like being surrounded by the species itself.
But local abundance does not always indicate a healthy species — monarch populations have declined 90 percent in the last 20 years, due to the destruction of milkweeds, the only plant the monarch caterpillars feed on.
The importance of bioabundance should direct our attention to the sturdy but sometimes ailing creatures that surround us — for example, to the fact that the number of trees in parts of L.A.’s urban forest has declined by more than half in the past 10 years, thanks to the ever-increasing construction of ever-larger houses. It takes effort to sustain these populations. If you’d like to help the monarchs, for example, you can create a mini migratory stopping point in your yard by planting milkweed. More broadly, essays in this series explore choices that we could make to make Los Angeles a friendlier place for bioabundance. I think these efforts are clearly worth it. The plankton and the bees sustain us. The butterflies and the parrots offer the chance to give ourselves over to the nonhuman world for moment. Our lives would be poorer without theirs.
This northern realm offers some of the most refreshing hikes in the state.
Following a screening of “Puzzle”, actress Kelly MacDonald, actor David Denman and director Mark Turtletaub attended a Q&A hosted by Cinema Series host Pete Hammond.
A Q&A will immediately follow the screening with Glenn Close, Jonathan Pryce, Christian Slater, Annie Starke and director Björn Runge.
The stocks of two of the largest private prison contractors skyrocketed in the month after President Trump’s inauguration and have continued to grow.
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Optical dating has been applied to sediments preserved in Little Sippewissett Marsh, Massachusetts, USA, which are associated with overwashing of the beach barrier during hurricane strikes on the coast. The aims were to determine the hurricane landfall frequency, and make comparisons with independent age control and the historical record. Written sources of hurricane activity along the American east coast are only considered reliable back to the mid 19th century, but the sedimentary record is potentially much longer. Optical dating was applied to quartz grains extracted from thirteen samples within a sediment core from the salt-marsh. Variability in the luminescence characteristics between aliquots was observed and ~ 33% of the measured aliquots were discarded based upon the ratio of the fast component to the medium component. The majority of the samples gave normal dose distributions implying homogeneous resetting of the luminescence signal at the time of deposition, but three of the samples required application of the minimum age model (MAM). Ages ranging between 20 ± 2 and 594 ± 38 years were obtained and are broadly in agreement with independent chronologies, thus demonstrating the potential of optical dating in this setting. The hurricane record based upon optical dating extends approximately 300 years further back in time than the official National Oceanic Atmospheric Administration (NOAA) record. The localised nature of hurricane landfalls means that it will be necessary to collect multiple cores from a number of different sites in order to build up a complete hurricane record for this part of the coast. © 2009 Elsevier B.V. All rights reserved.
Mendeley saves you time finding and organizing research
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Physicists seem to me always in pursuit of new postulated particles. They whimsically label properties of the subatomic particles called quarks as up, down, bottom, top, charm and strange.
As a mathematician, I find it delightful that new particles have been predicted because their existence would mean the mathematics (Group Theory) behind their behavior more symmetric and beautiful. It is that inherent belief in the beauty of nature that led them to their hypotheses, which included the properties of the postulated particles. It’s as if biologists predicted a new animal, which was raccoon-sized and loved strawberries. One need only take a raccoon trap and bait with strawberries. The physicists were able to build their trap and discover new particles.
Recently a single new high-energy neutrino called a ghost neutrino crashed into an atom in the Antarctica. It was detected by a cosmic team of 1,000 researchers. It is deemed to have originated from a black hole in a galaxy billions of light years away and thereby is a messenger from outer space. Heidi Schellman, a particle physicist at Oregon State University said “Scientists will be able to use these messengers to answer questions about distant cataclysms, test theories about the composition of the universe, and refine their understanding of the fundamental rules of physics.”
I am reminded of a memo from the Physics Department on a new element called administratium. Here’s its puckish description. I don’t know whom to credit for the original. I found it again on Google, but I can’t tell who deserves credit for delighting me.
Investigators at a major research institution have discovered the heaviest element known to science. This startling new discovery has been tentatively named Administratium (Ad). This new element has no protons or electrons, thus having an atomic number of 0.
It does, however, have 1 neutron, 125 assistant neutrons, 75 vice neutrons, and 111 assistant vice neutrons, giving it an atomic mass of 312. These 312 particles are held together by a force called morons, which are surrounded by vast quantities of lepton-like particles called peons. Since it has no electrons, Administratium is inert. However, it can be detected as it impedes every reaction with which it comes into contact.
According to the discoverers, a minute amount of Administratium causes one reaction to take over four days to complete when it would normally take less than a second. Administratium has a normal half-life of approximately three years; it does not decay but instead undergoes a reorganization in which a portion of the assistant neutrons, vice neutrons, and assistant vice neutrons exchange places.
In fact an Administratium sample’s mass will actually increase over time, since with each reorganization some of the morons inevitably become neutrons, forming new isotopes. This characteristic of moron promotion leads some scientists to speculate that Administratium is formed whenever morons reach a certain quantity in concentration. This hypothetical quantity is referred to as the “critical morass.”
This is a better representatiion of the minds of physicists than those on the Big Bang Theory. | <urn:uuid:75b43583-c528-4b86-b875-f1308058a647> | 3.1875 | 664 | Personal Blog | Science & Tech. | 35.626235 | 95,621,841 |
On-surface chemical reactions can lead to novel chemical compounds not yet synthesized by solution chemistry. The first-step, second-step, and third-step products can be analyzed in detail using a high-resolution atomic force microscope, as demonstrated in Nature Communications by scientists from the Swiss Nanoscience Institute and the Department of Physics at Basel University and their colleagues from Japan and Finland.
In numerous nanotechnology applications, individual molecules are placed on surfaces to fulfill specific functions – such as conducting an electrical current or emitting a light signal. Ideally, scientists will synthetize these sometimes extremely complex chemical compounds directly on the surface.
The on-surface chemical reactions can be followed step by step with the aid of ultra-high-resolution atomic force microscopes. The data obtained also enables them to calculate the precise molecular structure and the energetics along the path.
For their experiments, colleagues of Professor Ernst Meyer from the University of Basel selected a molecule consisting of three benzene rings joined by a triple bond. When the researchers apply this molecule to a silver surface, the molecules arrange themselves in a consistent pattern – but there is no chemical reaction.
Copper as a catalyst
On a copper surface, however, the molecules react already at a temperature of -123 °C. Catalyzed by the copper atoms, the precursor molecule incorporates two hydrogen atoms thereby altering its structure and spatial arrangement. When the sample is heated to 200 °C, a further reaction step takes place in which two pentagonal rings are formed.
A further increase in temperature to 400 °C causes a cleaving of hydrogen atoms and forms a further carbon-carbon bond. The final two reaction steps lead to aromatic hydrocarbon compounds, which had previously not been synthetized in solution chemistry.
The researchers conducted these experiments in ultra-high vacuum conditions and were able to monitor the synthesis using a high-resolution atomic force microscope with a carbon monoxide terminated tip. Comparative computer calculations generated the precise molecular structure, which perfectly matched the microscope images.
Through their experiments, the international research team has shown that on-surface chemistry can lead to novel products. “This extremely pure form of chemistry provides us with tailored on-surface nanostructures that can be used in a variety of ways,” says Meyer, commenting on the work largely performed by Dr. Shigeki Kawai. In the example presented, the copper surface functions as a catalyst; the chemical reaction of the precursor molecules is controlled by adding heat and can be monitored via atomic force microscopy.
Shigeki Kawai, Ville Haapasilta, Benjamin D. Lindner, Kazukuni Tahara, Peter Spijker, Jeroen A. Buitendijk, Rémy Pawlak, Tobias Meier, Yoshito Tobe, Adam S. Foster, and Ernst Meyer
Thermal control of a sequential on-surface transformation of a hydrocarbon molecule on copper surface
Nature Communications (2016), doi: 10.1038/ncomms12711
Professor Ernst Meyer, University of Basel, Department of Physics, tel. +41 61 267 37 24, email: email@example.com
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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.
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Two Northeastern University researchers and their international colleagues have created an advanced model aimed at exploring the role of neutral evolution in the biogeographic distribution of ocean microbes.
Their findings were published Thursday in the journal Science. The paper—titled “Biogeographic patterns in ocean microbes emerge in a neutral agent-based model”—was co-authored by Ferdi Hellweger, a microbial ecology expert and an associate professor of civil and environmental engineering; his doctoral student Neil Fredrick, PhD’15; and oceanographer Erik van Sebille of Australia’s University of New South Wales.
Over the past several decades, ecologists have come to understand that both natural selection and neutral evolution—that variation within and between species is caused by genetic drift and random mutations—play a role in the biogeographic patterns of ocean microbes.
In this study, Hellweger et al. quantified the role of neutral processes by simulating division, mutation, and death of some 100,000 individual marine bacteria cells with full genomes in a global surface ocean circulation model. They ran the model for up to 100,000 years and then analyzed the output using advanced DNA alignment algorithms.
Their results flew in the face of the long held notion that microbes are infinitely mobile—that the same cells could be found anywhere in the world’s oceans, unhindered by geographic boundaries. On the contrary, the researchers found that microbes evolve faster than the ocean circulation can disperse them, leading to substantial—and dynamic— biogeographic patterns in their surface ocean population.
“Microbes differ between provinces because of neutral evolution and dispersal limitation,” said Hellweger, whose ongoing research on this topic is supported by grants from the National Science Foundation and the National Oceanic and Atmospheric Administration. “Because provinces are not well-mixed, the differences can continue to grow.”
What’s more, the findings shed light on how ocean microbes may respond to global climate change. “You may not see microbes adapt to climate change as rapidly if ocean microbes were completely mixed and they were everywhere,” Hellweger posited. “Certain species of microbes may not thrive under new temperatures in certain provinces.”
Up next: Hellweger, Fredrick, and van Sebille will use a similar modeling approach to explore deep ocean microbes in addition to environmental selection.
Jason Kornwitz | Eurek Alert!
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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...
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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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Authors: George Rajna
Scientists led by Daigo Shoji from the Earth-Life Science Institute (Tokyo Institute of Technology) have shown that a type of artificial intelligence called a convolutional neural network can be trained to categorize volcanic ash particle shapes. Intel's Gadi Singer believes his most important challenge is his latest: using artificial intelligence (AI) to reshape scientific exploration. Artificial intelligence is astonishing in its potential. It will be more transformative than the PC and the Internet. Already it is poised to solve some of our biggest challenges. In the search for extraterrestrial intelligence (SETI), we've often looked for signs of intelligence, technology and communication that are similar to our own. Call it an a-MAZE-ing development: A U.K.-based team of researchers has developed an artificial intelligence program that can learn to take shortcuts through a labyrinth to reach its goal. In the process, the program developed structures akin to those in the human brain.
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Describe the following characteristics of the graph shown in Graph3.pdf:
1. Where is the function increasing, decreasing, or constant?
2. Are there any relative/absolute extrema? If so, where?
3. Is the graph smooth or choppy (piecewise)?
4. Are there any restrictions on the domain?
5. Are there any horizontal or vertical asymptotes?
6. How are the ends of the graph behaving?
7. Where are the x- and y-intercepts?
8. Write the equation.© BrainMass Inc. brainmass.com July 21, 2018, 10:00 am ad1c9bdddf
1. It's virtually impossible to tell the exact coordinates of the points where the graph reaches its "highs" and "lows," but the function is increasing on two intervals, which are given below (and whose endpoints should be considered estimates):
x < -10
-3 < x < 3:5
The function is decreasing on two intervals, which are given below (and whose endpoints should be considered estimates):
-10 < x < -3
x > 3.5
The function is probably not constant anywhere, unless the relatively long "horizontal line" at approximately x = -3 is actually indicative of a piecewise function (and not simply an artifact of the resolution afforded by the computer
or graphing calculator that was used to generate the graph).
2. There are relative maxima at approximately x = -10 and approximately x = 3.5; the relative maximum at approximately x = -10 is both a relative maximum and an absolute maximum. There is a relative minimum at approximately x = -3. There are no absolute minima, provided that the graph goes to negative infinity as x goes to ...
The various characteristics of the given graph are explained in detail (including provision of caveats in regard to what can/cannot definitely be inferred from it). | <urn:uuid:5ef115e9-7897-42f7-a346-795921734687> | 3.59375 | 410 | Tutorial | Science & Tech. | 53.9546 | 95,621,870 |
A relatively small black hole (20-30 times the mass of our Sun) can sustain a hugely voracious appetite while consuming material in an efficient and tidy manner – something previously thought impossible.
Figure 1. Artist’s visualization of the environment around M101 ULX-1, showing a stellar-mass black hole (foreground) with accretion disk. Gas from the Wolf-Rayet star (background) feeds the black hole’s voracious appetite. Gemini Observatory/AURA artwork by Lynette Cook.
Figure 2. ULX-1 is located near a spiral arm of M101. The image for M101 is composed from X-ray (Chandra X-ray Observatory; Purple), Infrared (Spitzer Satellite; Red), Optical (Hubble Space Telescope; Yellow) and Ultraviolet (GALEX satellite; Blue).Credit: Chandra X-ray Observatory, Spitzer Satellite, Hubble Space Telescope, and GALEX Satellite.
The research also affects the long quest for elusive intermediate-mass black holes. The findings are published in the November 28, 2013, issue of the journal Nature.The complete Nature paper can be accessed at:
“It has elegant manners,” says research team member Stephen Justham, of the National Astronomical Observatories of China, Chinese Academy of Sciences. Such lightweights, he explains, must devour matter at close to their theoretical limits of consumption to sustain the kind of energy output observed. "We thought that when small black holes were pushed to these limits, they would not be able to maintain such refined ways of consuming matter," Justham explains. "We expected them to display more complicated behavior when eating so quickly. Apparently we were wrong."
A Surprising Twist
X-ray sources give off high- and low-energy X-rays, which astronomers call hard and soft X-rays, respectively. In what might seem like a contradiction, larger black holes tend to produce more soft X-rays, while smaller black holes tend to produce relatively more hard X-rays. This source, called M101 ULX-1, is dominated by soft X-rays, so researchers expected to find a larger black hole as its energy source.
In a surprising twist, however, the new observations made at the Gemini Observatory, and published in the November 28th issue of the journal Nature, indicate that M101 ULX-1’s black hole is on the small side, and astrophysicists don’t understand why.
In theoretical models of how matter falls into black holes and radiates energy, the soft X-rays come primarily from the accretion disk (see illustration), while hard X-rays are typically generated by a high-energy “corona” around the disk. The models show that the corona’s emission strength should increase as the rate of accretion gets closer to the theoretical limit of consumption. Interactions between the disk and corona are also expected to become more complex.
Based on the size of the black hole found in this work, the region around M101-ULX-1 should, theoretically, be dominated by hard X-rays and appear structurally more complicated. However, that isn’t the case.
“Theories have been suggested which allow such low-mass black holes to eat this quickly and shine this brightly in X-rays. But those mechanisms leave signatures in the emitted X-ray spectrum, which this system does not display,” says lead author Jifeng Liu, of the National Astronomical Observatories of China, Chinese Academy of Sciences. “Somehow this black hole, with a mass only 20-30 times the mass of our Sun, is able to eat at a rate near to its theoretical maximum while remaining relatively placid. It’s amazing. Theory now needs to somehow explain what’s going on.”
An Intermediate-mass Black Hole Dilemma
The discovery also delivers a blow to astronomers hoping to find conclusive evidence for an “intermediate-mass” black hole in M101 ULX-1. Such black holes would have masses roughly between 100 and 1000 times the mass of the Sun, placing them between normal stellar-mass black holes and the monstrous supermassive black holes that reside in the centers of galaxies. So far these objects have been frustratingly elusive, with potential candidates but no broadly-accepted detection. Ultra-luminous X-ray sources (ULXs) have been one of the main proposed hiding places for intermediate-mass black holes, and M101 ULX-1 was one of the most promising-looking contenders.
“Astronomers hoping to study these objects will now have to focus on other locations for which indirect evidence of this class of black holes has been suggested, either in the even brighter ‘hyper-luminous’ X-ray sources or inside some dense clusters of stars,” explains research team member Joel Bregman of the University of Michigan.
“Many scientists thought it was just a matter of time until we had evidence for an intermediate-mass black hole in M101 ULX-1,” says Liu. But the new Gemini findings both take away some of that hope to solve an old puzzle and adds the fresh mystery of how this stellar-mass black hole can consume matter so calmly.
To determine the mass of the black hole, the researchers used the Gemini Multi-Object Spectrograph at the Gemini North telescope on Mauna Kea, Hawai‘i to measure the motion of the companion. This star, which feeds matter to the black hole, is of the Wolf-Rayet variety. Such stars emit strong stellar winds, from which the black hole can then draw in material. This study also revealed that the black hole in M101 ULX-1 can capture more material from that stellar wind than astronomers had anticipated.
M101 ULX-1 is ultra-luminous, shining a million times more brightly than the Sun in both X-rays (from the black hole accretion disk) and in the ultraviolet (from the companion star). Co-author Paul Crowther from the University of Sheffield in the United Kingdom adds, "Although this isn't the first Wolf-Rayet black hole binary ever discovered, at some 22 million light-years away, it does set a new distance record for such a system. The Wolf-Rayet star will have died in a small fraction of the time it has taken for light to reach us, so this system is now likely a double black hole binary."“Studying objects like M101 ULX-1 in distant galaxies gives us a vastly larger sampling of the diversity of objects in our universe,” says Bregman. “It’s absolutely amazing that we have the technology to observe a star orbiting a black hole in another galaxy this far away.”
Gemini's mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.
The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai'i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.
The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country's contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.
Media Contacts:Peter Michaud
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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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There are a number of hot topic environmental issues right now. Name some that are affecting you? Then discuss what you believe your environmental responsibilities are in relation to these issues? Do you always measure up to your responsibilities to the environment? Do you fall short? Explain why or why not.© BrainMass Inc. brainmass.com July 23, 2018, 10:04 am ad1c9bdddf
Global warming, Ozone depletion and acid rain are some of the burning environmental issue for the mankind. Global warming occurs due to excessive accumulation of Greenhouse gases (GHGs). These are gaseous components of the atmosphere that contribute to the greenhouse effect. Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases. Major cause of the increased greenhouse gas is anthropogenic activities. Some of the main sources of greenhouse gases due to human activity include:
a. burning of fossil fuels and deforestation leading to higher carbon dioxide concentrations
b. paddy rice farming, land use and wetland changes, pipeline losses, and covered vented landfill emissions contributes methane to atmospheric concentrations
c. use of chlorofluorocarbons (CFCs) in refrigeration systems, and use of CFCs and halons in fire suppression systems and manufacturing processes
d. agricultural activities, including the use of fertilizers, that lead to higher nitrous oxide concentrations
Effect of Global Warming:
More Frequent Extreme Weather
The year 1999 was the fifth-warmest year on record since the mid-1800's; 1998 being the warmest year. According to Thomas Karl, director of the National Climatic ...
Global warming is thoroughly discussed in this solution. | <urn:uuid:e60dfae2-54f3-4eb7-9bbb-48f8dbaea49a> | 3.390625 | 379 | Truncated | Science & Tech. | 30.688251 | 95,621,896 |
In support of the first Tropospheric Ozone Assessment Report (TOAR) a relational database of global surface ozone observations has been developed and populated with hourly measurement data and enhanced metadata. A comprehensive suite of ozone data products including standard statistics, health and vegetation impact metrics, and trend information, are made available through a common data portal and a web interface. These data form the basis of the TOAR analyses focusing on human health, vegetation, and climate relevant ozone issues, which are part of this special feature.
Cooperation among many data centers and individual researchers worldwide made it possible to build the world's largest collection of in-situ hourly surface ozone data covering the period from 1970 to 2015. By combining the data from almost 10,000 measurement sites around the world with global metadata information, new analyses of surface ozone have become possible, such as the first globally consistent characterisations of measurement sites as either urban or rural/remote. Exploitation of these global metadata allows for new insights into the global distribution, and seasonal and long-term changes of tropospheric ozone and they enable TOAR to perform the first, globally consistent analysis of present-day ozone concentrations and recent ozone changes with relevance to health, agriculture, and climate.
Considerable effort was made to harmonize and synthesize data formats and metadata information from various networks and individual data submissions. Extensive quality control was applied to identify questionable and erroneous data, including changes in apparent instrument offsets or calibrations. Such data were excluded from TOAR data products. Limitations of a posteriori data quality assurance are discussed. As a result of the work presented here, global coverage of surface ozone data for scientific analysis has been significantly extended. Yet, large gaps remain in the surface observation network both in terms of regions without monitoring, and in terms of regions that have monitoring programs but no public access to the data archive. Therefore future improvements to the database will require not only improved data harmonization, but also expanded data sharing and increased monitoring in data-sparse regions.
Elementa: Science of the Anthropocene
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This work is licensed under a Creative Commons Attribution 4.0 License.
Schultz, Martin G.; Schroder, Sabine; Lyapina, Oleg; Cooper, Owen; Galbally, Ian; Petropavlovskikh, Irina; Mazzoleni, Lynn; and et al., "Tropospheric Ozone assessment report: database and metrics data of global surface Ozone observations" (2017). Department of Chemistry Publications. 90. | <urn:uuid:41ef957a-2246-432c-8b8c-9e83eca11c4e> | 2.96875 | 518 | Academic Writing | Science & Tech. | 8.423402 | 95,621,910 |
- We discuss the design of a linker for the Intel 8088/80×86 processors which resembles LINK of MS-DOS in many respects.
- It may be noted that the object modules of MS-DOS differ from the Intel specifications in some respects.
Object Module Format (Explain object module of the program)
- An Intel 8088 object module is a sequence of object records, each object record describing specific aspects of the programs in the object module.
- There are 14 types of object records containing the following five basic categories of information:
Binary image (i.e. code generated by a translator)
Debugging information (e.g. line number in source program).
Miscellaneous information (e.g. comments in the source program).
- We only consider the object records corresponding to first three categories-a total of eight object record types.
- Each object record contains variable length information and may refer to the contents of previous object records.
- Each name in an object record represented in the following format: length( 1 byte)name | <urn:uuid:08fca184-fa76-4fb4-a6ca-f37a8d7fa6e7> | 2.796875 | 220 | Documentation | Software Dev. | 46.379387 | 95,621,923 |
The Atomic Moments and Hyperfine Fields in Fe2Ti and Fe2Zr
The magnetic properties of Fe2Ti and Fe2Zr, intermetallic compounds with Laves type structures, were studied using the techniques of neutron diffraction and nuclear resonance fluorescence (Mössbauer effect). Both compounds are ferromagnetic, with magnetic moments of 0.35 and 2.56 Bohr magnetons, respectively, at room temperature, and 0.92 and 3.12 Bohr magnetons, respectively, at liquid helium temperatures. A magnetic form factor for the iron atoms in Fe2Zr was determined. The nuclear resonance fluorescence experiments gave measures of the magnetic fields at the iron nuclei. At room temperature, the field for Fe2Zr was 190±10 kgauss, while that for Fe2Ti was very low, less than 5 kgauss. The relation between the atomic magnetic moments and the magnetic fields at the nuclei is discussed.
KeywordsIron Atom Hyperfine Field Lave Phase Bohr Magneton Iron Site
- 1.F. Laves and H. Witte, Metallwirtschaft 14, 645 (1935).Google Scholar | <urn:uuid:503518ea-6311-4f64-b509-82f6814be1e8> | 2.75 | 245 | Academic Writing | Science & Tech. | 48.017308 | 95,621,939 |
Using XMM-Newton, astronomers have obtained the world’s deepest ‘wide screen’ X-ray image of the cosmos to date. Their observations show newly discovered clusters of galaxies and provide insights into the structure of the distant Universe…
Unlike grains of sand on a beach, matter is not uniformly spread throughout the Universe. Instead, it is concentrated into galaxies like our own which themselves congregate into clusters. These clusters are ‘strung’ throughout the Universe in a web-like structure. Astronomers have studied this large-scale structure of the nearby Universe but have lacked the instruments to extend the search to the large volumes of the distant Universe.
Thanks to its unrivalled sensitivity, in less than three hours, ESA’s X-ray observatory XMM-Newton can see back about 7000 million years to a cosmological era when the Universe was about half its present size, and clusters of galaxies more tightly packed. Marguerite Pierre, CEA Saclay, France, with a European and Chilean team, used this ability to search for remote clusters of galaxies and map out their distribution.
Monica Talevi | alfa
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....
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Astronomical masers (the radio wavelength analogs of lasers) were first identified in space over fifty years ago and have since been seen in many locations; astronomical lasers have since been seen as well. Some of the most spectacular masers are found in regions of active star formation; in one case the region radiates as much energy in a single spectral line as does our Sun in its entire visible spectrum. Typically the maser radiation comes from molecules like water or OH that are excited by collisions and the radiation environment around young stars. In 1989, maser emission from atoms of atomic hydrogen gas was discovered around the star MWC349.
This post was originally published on this siteCataclysmic variable stars (CVs) are white dwarf stars that are accreting from an orbiting, low mass binary companion star. The accretion is facilitated by the proximity of the […]
This post was originally published on this siteHydrogen sulfide, the gas that gives rotten eggs their distinctive odor, permeates the upper atmosphere of the planet Uranus – as has been long debated, but never definitively […]
This post was originally published on this siteNear-Earth objects (NEOs) are small solar system bodies whose orbits sometimes bring them close to the Earth, potentially threatening a collision. NEOs are tracers of the composition, dynamics […] | <urn:uuid:2f2bd1c7-c007-4eea-b182-cdb559e48a1d> | 3.546875 | 270 | Content Listing | Science & Tech. | 10.921184 | 95,621,979 |
- Climate Change Impacts in the United States: The Third National Climate Assessment
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Figure : overview-as-oceans-absorb-co-they-become-more-acidic
As Oceans Absorb CO2 They Become More Acidic
This figure appears in chapter 1 of the Climate Change Impacts in the United States: The Third National Climate Assessment report.
The correlation between rising levels of carbon dioxide in the atmosphere (red) with rising carbon dioxide levels (blue) and falling pH in the ocean (green). As carbon dioxide accumulates in the ocean, the water becomes more acidic (the pH declines). (Figure source: modified from Feely et al. 20091ee9bb2b-9b22-48f0-b540-f942ccfd9c71).
When citing this figure, please reference modified from Feely et al. 20091ee9bb2b-9b22-48f0-b540-f942ccfd9c71.
Copyright protected. Obtain permission from the original figure source.
Other figures containing images in this figure : 2.30: As Oceans Absorb CO2, They Become More Acidic
was derived from
Ocean Acidification: Present Conditions and Future Changes in a High-CO2 World
This figure is composed of this image :
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In the theory of several complex variables and complex manifolds in mathematics, a Stein manifold is a complex submanifold of the vector space of n complex dimensions. They were introduced by and named after Karl Stein (1951). A Stein space is similar to a Stein manifold but is allowed to have singularities. Stein spaces are the analogues of affine varieties or affine schemes in algebraic geometry.
A complex manifold of complex dimension is called a Stein manifold if the following conditions hold:
- is again a compact subset of . Here denotes the ring of holomorphic functions on .
- is holomorphically separable, i.e. if are two points in , then there is a holomorphic function
- such that
Non-compact Riemann surfaces are Stein
Let X be a connected, non-compact Riemann surface. A deep theorem of Heinrich Behnke and Stein (1948) asserts that X is a Stein manifold.
Another result, attributed to Hans Grauert and Helmut Röhrl (1956), states moreover that every holomorphic vector bundle on X is trivial.
In particular, every line bundle is trivial, so . The exponential sheaf sequence leads to the following exact sequence:
Now Cartan's theorem B shows that , therefore .
This is related to the solution of the Cousin problems, and more precisely to the second Cousin problem.
Properties and examples of Stein manifolds
- The standard complex space is a Stein manifold.
- Every domain of holomorphy in is a Stein manifold.
- It can be shown quite easily that every closed complex submanifold of a Stein manifold is a Stein manifold, too.
- The embedding theorem for Stein manifolds states the following: Every Stein manifold of complex dimension can be embedded into by a biholomorphic proper map.
These facts imply that a Stein manifold is a closed complex submanifold of complex space, whose complex structure is that of the ambient space (because the embedding is biholomorphic).
- Every Stein manifold of (complex) dimension n has the homotopy type of an n-dimensional CW-Complex.
- In one complex dimension the Stein condition can be simplified: a connected Riemann surface is a Stein manifold if and only if it is not compact. This can be proved using a version of the Runge theorem for Riemann surfaces, due to Behnke and Stein.
- Every Stein manifold is holomorphically spreadable, i.e. for every point , there are holomorphic functions defined on all of which form a local coordinate system when restricted to some open neighborhood of .
- Being a Stein manifold is equivalent to being a (complex) strongly pseudoconvex manifold. The latter means that it has a strongly pseudoconvex (or plurisubharmonic) exhaustive function, i.e. a smooth real function on (which can be assumed to be a Morse function) with , such that the subsets are compact in for every real number . This is a solution to the so-called Levi problem, named after E. E. Levi (1911). The function invites a generalization of Stein manifold to the idea of a corresponding class of compact complex manifolds with boundary called Stein domains. A Stein domain is the preimage . Some authors call such manifolds therefore strictly pseudoconvex manifolds.
- Related to the previous item, another equivalent and more topological definition in complex dimension 2 is the following: a Stein surface is a complex surface X with a real-valued Morse function f on X such that, away from the critical points of f, the field of complex tangencies to the preimage Xc = f-1(c) is a contact structure that induces an orientation on Xc agreeing with the usual orientation as the boundary of f-1(-?,c). That is, f-1(-?,c) is a Stein filling of Xc.
Numerous further characterizations of such manifolds exist, in particular capturing the property of their having "many" holomorphic functions taking values in the complex numbers. See for example Cartan's theorems A and B, relating to sheaf cohomology. The initial impetus was to have a description of the properties of the domain of definition of the (maximal) analytic continuation of an analytic function.
In the GAGA set of analogies, Stein manifolds correspond to affine varieties.
Stein manifolds are in some sense dual to the elliptic manifolds in complex analysis which admit "many" holomorphic functions from the complex numbers into themselves. It is known that a Stein manifold is elliptic if and only if it is fibrant in the sense of so-called "holomorphic homotopy theory".
Relation to smooth manifolds
Every compact smooth manifold of dimension 2n, which has only handles of index Thurston-Bennequin framing). Every closed smooth 4-manifold is a union of two Stein 4-manifolds glued along their common boundary.
- ^ PlanetMath: solution of the Levi problem
- ^ Yakov Eliashberg, Topological characterization of Stein manifolds of dimension > 2, International Journal of Mathematics vol. 1, no 1 (1990) 29-46.
- ^ Robert Gompf, Handlebody construction of Stein surfaces, Annals of Mathematics 148, (1998) 619-693.
- ^ Selman Akbulut and Rostislav Matveyev, A convex decomposition for four-manifolds, International Mathematics Research Notices (1998), no.7, 371-381. MR1623402
- Forster, Otto (1981), Lectures on Riemann surfaces, Graduate Text in Mathematics, 81, New-York: Springer Verlag, ISBN 0-387-90617-7 (including a proof of Behnke-Stein and Grauert-Röhrl theorems)
- Hörmander, Lars (1990), An introduction to complex analysis in several variables, North-Holland Mathematical Library, 7, Amsterdam: North-Holland Publishing Co., ISBN 978-0-444-88446-6, MR 1045639 (including a proof of the embedding theorem)
- Gompf, Robert E. (1998), "Handlebody construction of Stein surfaces", Annals of Mathematics, Second Series, The Annals of Mathematics, Vol. 148, No. 2, 148 (2): 619-693, arXiv:math/9803019 , doi:10.2307/121005, ISSN 0003-486X, JSTOR 121005, MR 1668563 (definitions and constructions of Stein domains and manifolds in dimension 4)
- Grauert, Hans; Remmert, Reinhold (1979), Theory of Stein spaces, Grundlehren der Mathematischen Wissenschaften, 236, Berlin-New York: Springer-Verlag, ISBN 3-540-90388-7, MR 0580152
- Stein, Karl (1951), "Analytische Funktionen mehrerer komplexer Veränderlichen zu vorgegebenen Periodizitätsmoduln und das zweite Cousinsche Problem", Math. Ann. (in German), 123: 201-222, doi:10.1007/bf02054949, MR 0043219 | <urn:uuid:3f02c6d4-b6a5-4d16-92e0-652e1f0c084a> | 2.875 | 1,562 | Knowledge Article | Science & Tech. | 47.330756 | 95,621,993 |
This website contains lecture notes on differential geometry and general relativity provided by a university mathematics professor. The lecture notes start with the necessary mathematical tools (vectors, geometry and tensors), and then explain general relativity and its consequences. At the bottom of the page references and suggested further readings can be found. The latest version of the notes (last updated in 2014) can be downloaded in PDF format.
%0 Electronic Source %A Waner, Stefan %D January 1, 2014 %T Introduction to Differential Geometry and General Relativity %V 2018 %N 23 July 2018 %8 January 1, 2014 %9 text/html %U http://www.zweigmedia.com/diff_geom/tc.html
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Authors: Hans-Joerg Hochecker
The matter-waves, well-known from numerous experiments, can be described as beat waves of two counter-moving waves. Thus mass is oscillating space-time, which results from the superposition of two counter-moving space-time waves. The duality of this counter-motion derives the duality of the electric force. And the inertia of the mass arises from the frequency. The electric force arises from a space- or energy- shift. Gravitation arises from the change of the energy-density of the electric field (by which the gravitational acceleration is independent of the mass) and yields the same results as GR. And the magnetic field appears to be an angle between the direction in which the electric field propagates and the direction in which it exerts its force.
Comments: 17 Pages. International Journal of Physics. 2017; 5(4):121-134. doi: 10.12691/ijp-5-4-4
[v1] 2017-07-23 04:40:45
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A university study into the incubation behavior of modern birds is shedding new light on the type of parental care carried out by their long extinct ancestors.
The study, by researchers at George Mason University and University of Lincoln (United Kingdom), aimed to test the hypothesis that data from exisiting birds could be used to predict the incubation behaviour of Theropods, a group of carnivorous dinosaurs from which birds descended.
The paper, out today in Biology Letters, was co-written by Geoff Birchard from the Department of Environmental Science and Policy at Mason and Charles Deeming and Marcello Ruta from the University of Lincoln's School of Life Sciences.
A 2009 study in the journal Science suggested that it was males of the small, carnivorous dinosaurs Troodon and Oviraptor that incubated their eggs. However, by taking into account factors known to affect egg and clutch mass in living bird species, the authors found that shared incubation with mature young was the ancestral incubation behavior rather than male-only incubation, which had been claimed previously for these Theropod dinosaurs."The previous study was carried out to infer the type of parental care in dinosaurs that are closely related to birds," said Birchard. "That study proposed that paternal care was present in these dinosaurs and this form of care was the ancestral condition for birds. Our new analysis, based on three times as many species as in the previous study, indicates that parental care cannot be inferred from simple analyses of the relationship of body size to clutch mass. Such analyses have to take into account factors such as shared evolutionary history and maturity at hatching.
"Irrespective of whether you accept the idea of Theropod dinosaurs sitting on eggs like birds or not, the analysis raised some concerns that we wanted to address," said Deeming. "Our analysis of the relationship between female body mass and clutch mass was interesting in its own right, but also showed that it was not possible to conclude anything about incubation in extinct distant relatives of the birds."
The project has helped in understanding the factors affecting the evolution of incubation in birds. More importantly it is hoped that the new analysis will assist palaeontologists in their interpretation of future finds of dinosaur reproduction in the fossil record.
Tara Laskowski | EurekAlert!
Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides
16.07.2018 | Tokyo Institute of Technology
The secret sulfate code that lets the bad Tau in
16.07.2018 | American Society for Biochemistry and Molecular Biology
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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Kundt's tube is an experimental acoustical apparatus invented in 1866 by German physicist August Kundt for the measurement of the speed of sound in a gas or a solid rod. It is used today only for demonstrating standing waves and acoustical forces.
How it works
The tube is a transparent horizontal pipe which contains a small amount of a fine powder such as cork dust, talc or Lycopodium. At one end of the tube is a source of sound at a single frequency (a pure tone). Kundt used a metal rod resonator that he caused to vibrate or 'ring' by rubbing it, but modern demonstrations usually use a loudspeaker attached to a signal generator producing a sine wave. The other end of the tube is blocked by a movable piston which can be used to adjust the length of the tube.
The sound generator is turned on and the piston is adjusted until the sound from the tube suddenly gets much louder. This indicates that the tube is at resonance. This means the length of the round-trip path of the sound waves, from one end of the tube to the other and back again, is a multiple of the wavelength λ of the sound waves. Therefore the length of the tube is a multiple of half a wavelength. At this point the sound waves in the tube are in the form of standing waves, and the amplitude of vibrations of air are zero at equally spaced intervals along the tube, called the nodes. The powder is caught up in the moving air and settles in little piles or lines at these nodes, because the air is still and quiet there. The distance between the piles is one half wavelength λ/2 of the sound. By measuring the distance between the piles, the wavelength λ of the sound in air can be found. If the frequency f of the sound is known, multiplying it by the wavelength gives the speed of sound c in air:
By filling the tube with other gases besides air, and partially evacuating it with a vacuum pump, Kundt was also able to calculate the speed of sound in different gases at different pressures. To create his vibrations, Kundt stopped the other end of the tube with a loose fitting stopper attached to the end of a metal rod projecting into the tube, clamped at its center. When it was rubbed lengthwise with a piece of leather coated with rosin, the rod vibrated longitudinally at its fundamental frequency, giving out a high note. Once the speed of sound in air was known, this allowed Kundt to calculate the speed of sound in the metal of the resonator rod. The length of the rod L was equal to a half wavelength of the sound in metal, and the distance between the piles of powder d was equal to a half wavelength of the sound in air. So the ratio of the two was equal to the ratio of the speed of sound in the two materials:
Reason for accuracy
A less accurate method of determining wavelength with a tube, used before Kundt, is simply to measure the length of the tube at resonance, which is approximately equal to a multiple of a half wavelength. The problem with this method is that when a tube of air is driven by a sound source, its length at resonance is not exactly equal to a multiple of the half-wavelength. Because the air at the source end of the tube, next to the speaker's diaphragm, is vibrating, it is not exactly at a node (point of zero amplitude) of the standing wave. The node actually occurs some distance beyond the end of the tube. Kundt's method allowed the actual locations of the nodes to be determined with great accuracy.
- Chladni plates, another standing wave visualization technique.
- Rubens' tube, demonstrates the relationship between standing sound waves and sound pressure.
- Kundt, A. (1866). "Ueber eine neue Art Akustischer Staubfiguren und über die Anwendung derselben zur Bestimmung der Shallgeschwindigkeit in festen Körpern und Gasen". Annalen der Physik (in German). Leipzig: J. C. Poggendorff. 127 (4): 497–523. Bibcode:1866AnP...203..497K. doi:10.1002/andp.18662030402. Retrieved 2009-06-25.
- Kundt, August (January–June 1868). "Acoustic Experiments". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. Vol. 35 no. 4. UK: Taylor & Francis,. pp. 41–48. Retrieved 2009-06-25.
- Poynting, John Henry; Thomson, J. J. (1903). A Textbook of Physics: Sound (3rd ed.). London: Charles Griffin & Co. pp. 115–117.
- Faber, T. E. (1995). Fluid Dynamics for Physicists. UK: Cambridge University Press. p. 287. ISBN 0-521-42969-2.
- Hortvet, J. (1902). A manual of elementary practical physics. Minneapolis: H.W. Wilson. Page 119+. | <urn:uuid:9fef7f3c-74dc-4406-afe6-3480723823e0> | 4.09375 | 1,083 | Knowledge Article | Science & Tech. | 67.253056 | 95,622,034 |
It's a Trap! Using Phylogenetics to Detail Plant Decoy Defenses
Credit: Earlham Institute
Published in Genome Biology, novel research has shed further light on how plants can use ‘baits’ to recognize and trap disease-causing pathogens before infection can take hold.
The recent research, led by the Krasileva Group of Earlham Institute and The Sainsbury Laboratory, used phylogenetics (the study of how DNA sequences are related) to identify how these ‘bait’ genes are distributed throughout various wild and domestic grasses, including important crop plants such as wheat, barley, maize and rice. This fresh evidence could help scientists and breeders especially in arming crop plants against a swathe of emerging diseases.
By looking at the genetic history of these plants, the team found several interesting groups that gravitated towards forming novel fusions with plant receptors, which were most diverse in the wheat crop. These proteins are involved in plant stress responses in general, particularly in defense against pathogen attack.
“If we could understand better how these proteins with these additional ‘integrated’ domains were formed during recent evolution, then there is a good chance that we could engineer genes with specific domains to provide resistance to new types of pathogen attack,” says Paul Bailey, lead author of the study who performed the phylogenetic analysis.
The research team are primarily interested in bread wheat due to the complexity and size of its genetic make up, as well as eight other grass species’ genomes. Advancements in such genome sequencing have enabled the scientists to make comparisons of gene similarity between closely related species - wheat and barley, for example - and more distantly related species such as wheat and maize.
“We were intrigued to find that even between closely-related species, there can be significant variability between the type of fusion events that have occurred, indicating that the process is still active and ongoing in these plants,” added Paul.
Plants have an immune system that helps them recognize a range of pathogens, but they have to keep up with enemy fire that is perpetually evolving and constantly adapting new ways of getting around a plants primary defenses.
However, certain plant pathogen receptors known as ‘NLR’ proteins have been shown to be able to recognize some of the signals associated with disease-causing agents. By acquiring sections of proteins coded by other genes, which are often the target of pathogen infection, NLRs act as an ‘integrated defense decoy’.
Dr Ksenia Krasileva, who led the project, added: “When plants are able to evolve rapidly, they can respond to pathogens working their way around other defenses. Uncovering how plants stay healthy is still a challenge. This paper is a result of a successful collaboration of several genomics experts, including our group, Dr Matthew Moscou at TSL and Dr Wilfried Haerty at EI. Together, we uncovered one of the tricks plant use which will help to generate resistant crops.”
Plant pathogens are continually evolving, but in the future the research team hope to be able to generate novel proteins with specific integrated domains that give resistance to pathogens, particularly new threats to our crops.
This article has been republished from materials provided by the Earlham Institute. Note: material may have been edited for length and content. For further information, please contact the cited source.
Reference: Bailey, P. C., Schudoma, C., Jackson, W., Baggs, E., Dagdas, G., Haerty, W., … Krasileva, K. V. (2018). Dominant integration locus drives continuous diversification of plant immune receptors with exogenous domain fusions. Genome Biology, 19, 23. https://doi.org/10.1186/s13059-018-1392-6
Bioethics Council Rules Heritable Genome Editing "Ethically Acceptable" In Certain CircumstancesNews
A leading UK bioethics advisory body has weighed in on the debate around human genetic modification, concluding that heritable genome editing – modifying the DNA of an egg, sperm or embryo with changes that will be passed on to future generations – could be ‘morally permissible’ in humans, provided key ethical tests are met.
Genetic Factors Leading to Rare Bone Fusion Disorder IdentifiedNews
Genome sequencing establishes multiple genes responsible for a rare condition that cause bone fusionREAD MORE
Hay Fever Risk Genes Overlap with Autoimmune DiseaseNews
In a large international study involving almost 900,000 participants, researchers from the University of Copenhagen and COPSAC have found new risk genes for hay fever. It is the largest genetic study so far on this type of allergy, which affects millions of people around the world.READ MORE | <urn:uuid:8a2ce95a-37e4-451b-91a6-3b0bb38e663c> | 3.515625 | 995 | News Article | Science & Tech. | 30.016395 | 95,622,038 |
Date of publication: 2017-08-23 03:14
655 Don J. Easterbrook, John Gosse, et. aAl., ‘Evidence for Synchronous Global Climatic Events: Cosmogenic Exposure Ages of Glaciations’, in Don Easterbrook, Evidence-Based Climatic Science , Elsevier, August 7566, Chapter 7, p. 59.
The primary reason he embraced this theory, however, was not that he had become a convert to gradualism, but because he was never able to explain how a large enough area of the ice-cap to supply all the vast amounts of water needed for his flood could simply have melted all at once. He had proposed two possibilities – dramatic overnight global warming on the one hand, or volcanic activity under the ice cap on the other – but, as the reader will recall, he very quickly conceded there was no evidence for either. What Bretz did not consider, and could not consider – because the relevant data only began to come in quarter of a century after his death – was the possibility that the ice cap could have undergone cataclysmic melting as a result of a comet impact.
Secondly, and rather strikingly, The Greek lawmaker Solon visited Egypt around the year 655 BC and there he was told a very remarkable story by the priests at the Temple of Sais in the Nile Delta – a story that was eventually handed down to his more famous descendant Plato, who in due course shared it with the world in his Dialogues of Timaeus and Critias.
Severe and devastating enough in themselves, these factors nonetheless pale into insignificance when compared with the consequences of the hypothesized impacts on the ice cap:
The reaction of the geological establishment was one of stunned, embarrassed silence. To have strayed so far from the doctrine of uniformitarianism could only mean that Bretz must have gone mad. David Alt, Professor Emeritus of Geology at the University of Montana, describes one of the lectures that Bretz gave in which he expounded on the ideas in his 6978 paper:
Imo the last big catastrophe, flood and earthquakes would have been 66,555 years ago. There was also a meteor that hit South America which was stopped bouncing by the Andes. It was around this time. One of the causes of major earthquakes is where our planets are in our solar system. The same as there is no I in team, there is no I in solar system. It 8767 s a system that works together. The last major catastrophe occurred on the 9th of July 9988 bce. This video shows what caused many large killer earthquakes with the last one showing the 9988 bce date. https:///watch?v=TfGReuHKt5s
Such a view, in Clube and Napier’s prescient 6995 opinion, is dangerous in that its effect is to “place the human species a little higher than the ostrich, awaiting the fate of the dinosaur.” 658
“At conferences, audiences paid little heed to his presentations, giving short shrift to the evidence. Other researchers listened politely, then questioned his competence. The result was always the same. ‘When Jacques proposed [that Bluefish Caves was] 79,555 [years old], it was not accepted,’ says William Josie, director of natural resources at the Vuntut Gwitchin First Nation in Old Crow. In his office at the Canadian Museum of History, Cinq-Mars fumed at the wall of closed minds. Funding for his Bluefish work grew scarce. His fieldwork eventually sputtered and died.
In summary, not a single voice was raised in support of Bretz and there was much patronizing dismissal of his “outrageous hypothesis” of a single large flood. In particular, the massed geologists homed in on what they clearly believed was the fatal flaw in the case for a sudden and overwhelming cataclysm – namely that Bretz had failed to identify a convincing source for his floodwaters.
In 7558, scientists at Utah State were the first in the world to clone a hybrid animalaa mule, the typically sterile offspring of a donkey and a horse. The research ultimately spawned commercial equine-cloning labs. Now students and faculty churn out up to 655 cloned embryos a week, primarily for genetics research.
The IB recommends that students follow the completion of the written essay with a short, concluding interview with their supervisor. This is known as viva voce.
“In the past, much more powerful plasma events sometimes took place, due to solar outbursts and coronal mass ejections (CME’s) from the Sun, or possibly emissions from other celestial objects. Powerful plasma phenomena… hitting the surface of Earth could heat and fuse rock, incinerate flammable materials, melt ice caps, vaporize shallow bodies of water, creating an extended deluge of rain, and send the climate into a warming spell. The release of pressure that follows the melting of thousands-of-meters-thick ice sheets can induce earthquakes and even cause hot rock under pressure to melt and erupt to the surface as volcanoes…
Looking at the data, the implications of this new research were immediately obvious to me. What it offered, if it checked out, was an elegant and potentially revolutionary explanation both for the sudden onset of the Dryas itself and for the accompanying extinctions, and perhaps for much else besides – including the cataclysmic flooding that left its scars on the channeled scablands of Washington State.
“Tentative orbital parameters which could lead to its observation are estimated. It is predicted that in the near future (around the year 7585) the Earth will cross again that part of [the Taurid meteor stream] that contains the fragments, an encounter that in the past has dramatically affected mankind.” 666 | <urn:uuid:e08acfd0-94f1-4836-977e-917e1366d64c> | 2.71875 | 1,215 | Academic Writing | Science & Tech. | 42.156 | 95,622,039 |
Researchers at The University of Texas at Austin have discovered a new chemical reaction that has the potential to lower the cost and streamline the manufacture of compounds ranging from agricultural chemicals to pharmaceutical drugs.
Phenolic compounds, or phenols, are broadly used as disinfectants, fungicides and drugs to treat many ailments such as Parkinson’s disease. Creating a phenol seems deceptively simple. All it requires is replacing a hydrogen molecule on an aromatic hydrocarbon with an oxygen molecule.
“This is a chemical transformation that is underdeveloped and at the same time pivotal in the production of many chemicals important to life as we know it,” said Dionicio Siegel, an assistant professor of chemistry in the College of Natural Sciences at The University of Texas at Austin.
The secret that Siegel and his colleagues discovered is a substance called phthaloyl peroxide. This chemical was studied in the late 1950s and early 1960s, but it has been largely ignored during the intervening years.
The scientists were conducting basic studies on phthaloyl peroxide, building on previous research, and decided to use it to tackle the age-old problem of transforming aromatic hydrocarbons into phenols.
The advantage to using phthaloyl peroxide is that the reaction does not require the use of acids or catalysts to work, and it can add oxygen to a wide variety of starting materials.
“There are no special conditions,” said Siegel. “You just combine the reagents, mix them and go. It’s very simple and straight forward.”
The paper describing this discovery was published recently in Nature.
The new process can be applied to other problems in organic chemistry. One particular area of interest is creating metabolites to drugs. Metabolites are the products left after the body finishes breaking down, or metabolizing, a substance. When testing drugs, scientists need to take into account not just how the drug itself reacts in the body, but also how the metabolites react.
“We’ve had a long-standing interest in accessing metabolites of drugs or compounds that are used in biological systems,” said Siegel. “Just as it’s important that the drug doesn’t have deleterious side effects, it’s equally important that the metabolite doesn’t have an effect. You need to be able to test them, and there’s not really a direct way to access metabolites other than using liver microsomes, and that’s not efficient and it doesn’t always work.”
Another area where Siegel and his colleagues are applying what they have learned is in developing even more reactive agents that will expand the scope of chemicals that can be transformed. Siegel hopes to get this new process into the hands of others quickly. He is working with chemical supply companies to market the phthaloyl peroxide compound and/or the precursors and make it available to people in research and the pharmaceutical industry.
“It hasn’t even come out yet,” said Siegel, “but there are a lot of people that are already picking up the technique and working on it.”
Siegel is a co-author on the paper, along with his graduate student, Changxia Yuan, and two undergraduate researchers, Taylor Hernandez and Adrian Berriochoa. Two other co-authors, Kendall Houk and Yong Liang, are from the University of California, Los Angeles. | <urn:uuid:f9755320-1ac2-4e1e-b14c-688729b207f2> | 4.0625 | 723 | News Article | Science & Tech. | 35.600651 | 95,622,044 |
Question: Is &&= a valid Java operator?
Answer: No, it is not.
Question: Name the eight primitive Java types.
Answer: The eight primitive types are byte, char, short, int, long, float, double, and boolean.
Question: Which class should you use to obtain design information about an object?
Answer: The Class class is used to obtain information about an object's design.
Question: What is the relationship between clipping and repainting?
Answer: When a window is repainted by the AWT painting thread, it sets the clipping regions to the area of the window that requires repainting.
Question: Is "abc" a primitive value?
Answer: The String literal "abc" is not a primitive value. It is a String object.
Question: What is the relationship between an event-listener interface and an event-adapter class?
Answer: An event-listener interface defines the methods that must be implemented by an event handler for a particular kind of event. An event adapter provides a default implementation of an event-listener interface.
Question: What restrictions are placed on the values of each case of a switch statement?
Answer: During compilation, the values of each case of a switch statement must evaluate to a value that can be promoted to an int value.
Question: What modifiers may be used with an interface declaration?
Answer: An interface may be declared as public or abstract.
Question: Is a class a subclass of itself?
Answer: A class is a subclass of itself.
Question: What is the highest-level event class of the event-delegation model?
Answer: The java.util.EventObject class is the highest-level class in the event-delegation class hierarchy.
Question: What event results from the clicking of a button?
Answer: The ActionEvent event is generated as the result of the clicking of a button.
Question: How can a GUI component handle its own events?
Answer: A component can handle its own events by implementing the required event-listener interface and adding itself as its own event listener.
Question: What is the difference between a while statement and a dostatement?
Answer: A while statement checks at the beginning of a loop to see whether the next loop iteration should occur. A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.
Question: How are the elements of a GridBagLayout organized?
Answer: The elements of a GridBagLayout are organized according to a grid. However, the elements are of different sizes and may occupy more than one row or column of the grid. In addition, the rows and columns may have different sizes.
Question: What advantage do Java's layout managers provide over traditional windowing systems?
Answer: Java uses layout managers to lay out components in a consistent manner across all windowing platforms. Since Java's layout managers aren't tied to absolute sizing and positioning, they are able to accomodate platform-specific differences among windowing systems.
Question: What is the Collection interface?
Answer: The Collection interface provides support for the implementation of a mathematical bag - an unordered collection of objects that may contain duplicates.
Question: What modifiers can be used with a local inner class?Answer: A local inner class may be final or abstract. | <urn:uuid:b3a4b5c0-dabe-4f6c-a3f8-e16da1890a5d> | 2.625 | 721 | Q&A Forum | Software Dev. | 45.540892 | 95,622,063 |
- How did people in the olden days create software without any programming software?
- How can I tell if a certain tree is big enough to support a 30-foot zip line?
- Is chaos an actual state, or just a name for rules we haven’t discovered yet?
- Does the outside edge of a ceiling fan blade move faster than the inside edge?
- Can a computer generate a truly random number?
- How do computers perform complex mathematical operations?
- Is computer software always a step ahead of hardware?
- Can we use artificial intelligence to generate new ideas?
- Why is speed at sea measured in knots?
- Will we ever run out of music?
How were we able to navigate from the Earth to the Moon with such precision?
Before the days of GPS, engineers had to rely on good old fashioned computation…By Gwendolyn Vines Gettliffe
Plotting the path from a launch pad on Earth to a landing site on the moon — and back again — was made possible in the 1960s by using what we know of the mechanics of the two bodies. These are not easy calculations. After all, the Moon and Earth are moving along their own trajectories, one of them rotating quite quickly the whole time. Fortunately these movements are quite predictable, and there aren’t many twists and turns along the way. Once you’re on the right trajectory, it’s smooth sailing for several days.
However, that “right trajectory” may require lots of small adjustments, especially when you get to either end of the trip. To ensure the spacecraft doesn’t land on the edge of a crater on the Moon, or burn up or skip off into space upon reentry into the Earth’s atmosphere, it’s critical that the pilots are able to know three things about their spacecraft with great precision:
- Where it is in space and where it is going? (navigation)
- Which way it needs to go to stay on or return to the planned path? (guidance)
- How and when to fire its thrusters to match the planned path? (control)
For the Apollo space missions, engineers at the MIT Instrumentation Lab (now the Charles Stark Draper Laboratory) developed the Primary Guidance, Navigation, and Control System (PGNCS), which consisted of a computer, software, inertial measurement unit (IMU), and optical instruments. The crew used an optical sextant and telescope to measure the angles between stars and the Earth or Moon horizons; the computer would calculate those angles and provide the necessary navigation information. For its time, the Apollo guidance computer was state-of-the art. (Today, your hand-held device is capable of much, much more.)
Navigating to the moon requires data about current position and velocity with respect to some frame of reference. A large antenna on Earth, for example, can determine the distance from itself to the spacecraft by measuring the delay of a signal sent from Earth to the capsule and back. It can also determine radial velocity, or the rate at which the spacecraft is moving along the line between the antenna and spacecraft, using the Doppler effect to calculate the frequency difference of that signal and its returned version. Radio tracking is incredibly precise in the neighborhood of Earth, measuring a distance to less than 30 meters of error.
For guidance and control, the Apollo spacecraft featured a large engine and smaller reaction control system thrusters that, when fired, changed the roll, pitch, and yaw of the spacecraft, as well as providing thrust in what direction was necessary to get back on track. However, in order to fire the engines in a specific direction, the spacecraft had to know what its orientation in space was. That’s where the IMU came in. The IMU was about the size of a soccer ball and contained a platform mounted on three gimbals. Sensors on the gimbals could tell how many degrees the spacecraft was rotated around each axis with respect to the platform and thus report the orientation of the spacecraft to the crew via the computer. With that information, the crew could take the steps necessary to stay on course.
Thanks to Sanjoy, a 40-year-old from Delhi, for this question.
Posted: April 10, 2012 | <urn:uuid:e5ccab6e-58af-460e-9bb1-2f38878010fc> | 4.0625 | 890 | Q&A Forum | Science & Tech. | 47.261614 | 95,622,066 |
Point Defects in Simple Ionic Solids
Apart from man’s innate need to model and the satisfaction that a good model can bring, the real purpose of scientific modelling is to increase our understanding of a system. More importantly, it provides the basis from which to move forward to understand more complex systems and to design such new systems for specific applications by making predictions about their properties. Simple ionic solids, such as the alkali and silver halides, some fluoritestructured crystals and binary oxides, provide the most accessible and well-developed testing grounds for the study, both experimental and theoretical, of point defects in crystalline materials. This is because defects in these crystals typically carry a charge different from those on the ions that comprise the normal components of the matrix. Their presence, nature, interactions and movements can therefore be rather easily quantitatively determined through the measurement of readily observed macroscopic properties such as ionic conductivity. These charges can be present whether the defects are intrinsic or extrinsic. Intrinsic defects, such as Schottky or Frenkel defects, are equilibrium thermodynamic defects and exist in all materials because the balance between the enthalpy required for their formation in a perfect lattice and the resulting increase in the entropy of the system gives rise to a minimum in the Gibbs free energy. There is a corresponding equilibrium intrinsic defect concentration at each temperature.
KeywordsPoint Defect Silver Halide Perfect Lattice Defect Interaction Interionic Potential
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Tuesday, February 14, 2017
A “Mini Ice Age” Is Coming Soon Says Math Professor’s Solar Cycle Model That’s 97% Accurate
By: Arjun Walia
This has nothing to do with human impact on climate change, but instead the activity of the sun and how solar cycles impact our climate as well. It’s based on a mathematical model that shows the sun might “quiet” down in the coming years thus impacting our climate as well. This is not a climate change denial article, please read it before commenting.
A few months ago, NASA published a study showing that Antarctica is actually gaining more ice than it is losing. They made the announcement after using satellites to examine the heights of the region’s ice sheet. The findings contradict the prevailing theory that Antarctica has actually been shrinking, however. The paper is titled “Mass gains of the Antarctic ice sheet exceed losses” and was published in the Journal of Glaciology.
The authors of this study are from NASA’s Goddard Space Flight Center, and the cause of this ice gain isn’t entirely known, but a number of theories are mentioned in the paper. It is worth mentioning, however that NASA was blasted by dozens of their own scientists regarding their global warming stance, even though a number of the world’s top scientists have questioned just how much an impact greenhouse gases have on climate change. You can read more about that here. (source)
Perhaps there are other factors contributing to climate change?
There are many theories as to why this is so, and one of them includes the effects of supposed global warming, but not everyone agrees. That’s a completely separate topic, however, and you can learn more about it in the articles linked at the end of this article.
When it comes to climate change, a lot of emphasis is put on human activity, and rightfully so, as our ways here need to change. Perhaps in our fervour to discover our own culpability in this shift, however, we missed a few things along the way? What about the natural cycles of climate change Earth experiences, and has experienced? It’s a scientific fact that fluctuations in the solar cycle impact earth’s global temperature, as do other massive bodies flying in and around our solar system.
The most recent research to examine this topic comes from the National Astronomy Meeting in Wales, where Valentina Zharkova, a mathematics professor from Northumbria University (UK), presented a model that can predict what solar cycles will look like far more accurately than was previously possible. She states that the model can predict their influence with an accuracy of 97 percent, and says it is showing that Earth is heading for a “mini ice age” in approximately fifteen years.
According to the Royal Astronomical Society (RAS):
A new model of the Sun’s solar cycle is producing unprecedentedly accurate predictions of irregularities within the Sun’s 11-year heartbeat. The model draws on dynamo effects in two layers of the Sun, one close to the surface and one deep within its convection zone. Predictions from the model suggest that solar activity will fall by 60 per cent during the 2030s to conditions last seen during the ‘mini ice age’ that began in 1645. (source)
Zharkova and her team came up with the model using a method called “principal component analysis” of the magnetic field observations, from the Wilcox Solar Observatory in California. Looking forward to the next few solar cycles, her model predicts that from 2030 to 2040 there will be cause for a significant reduction in solar activity, which again, will lead to a mini ice age. According to Zharkova:
In cycle 26, the two waves exactly mirror each other – peaking at the same time but in opposite hemispheres of the Sun. Their interaction will be disruptive, or they will nearly cancel each other. We predict that this will lead to the properties of a “Maunder minimum.” Effectively, when the waves are approximately in phase, they can show strong interaction, or resonance, and we have strong solar activity. When they are out of phase, we have solar minimums. When there is full phase separation, we have the conditions last seen during the Maunder minimum, 370 years ago. (source)
Pretty interesting to think about it, isn’t it? With so much attention being paid to the warming of our planet, it would be quite a shocker to suddenly enter into an ice age.
Again, this has nothing to due with human impact on climate change, more so the activity of the sun and how solar cycles impact our climate as well. This is not a climate change denial article. It’s basically bringing up the fact that there are more factors to consider that play a role in climate change.What are your thoughts? Please feel free to share in the comments section below. | <urn:uuid:1f08645d-16aa-4fb0-8268-b3b98600ffed> | 3.21875 | 1,025 | Personal Blog | Science & Tech. | 43.532227 | 95,622,085 |
Science has known about plant hormones since Charles Darwin experimented with plant shoots and showed that the shoots bend toward the light as long as their tips, which are secreting a growth hormone, aren’t cut off.
But it is only recently that scientists have begun to put a molecular face on the biochemical systems that modulate the levels of plant hormones to defend the plant from herbivore or pathogen attack or to allow it to adjust to changes in temperature, precipitation or soil nutrients.
Now, a cross-Atlantic collaboration between scientists at Washington University in St. Louis, and the European Synchrotron Radiation Facility and the European Molecular Biology Laboratory, both in Grenoble, France, has revealed the workings of a switch that activates plant hormones, tags them for storage or marks them for destruction.
The research appeared online in the May 24 issue of Science Express and will be published in a forthcoming issue of Science.
“The enzymes are cellular stop/go switches that turn hormone responses on and off,” says Joseph Jez, PhD, associate professor of biology in Arts & Sciences at WUSTL and senior author on the paper.
The research is relevant not just to design of herbicides — some of which are synthetic plant hormones — but also to the genetic modification of plants to suit more extreme growing conditions due to unchecked climate change.
What plant hormones do
Plants can seem pretty defenseless. After all, they can’t run from the weed whacker or move to the shade when they’re wilting, and they don’t have teeth, claws, nervous systems, immune systems or most of the other protective equipment that comes standard with an animal chassis.
But they do make hormones. Or to be precise — because hormones are often defined as chemicals secreted by glands and plants don’t have glands — they make chemicals that in very low concentrations dramatically alter their development, growth or metabolism. In the original sense of the word “hormone,” which is Greek for impetus, they stir up the plant.
In plants as in animals, hormones control growth and development. For example, the auxins, one group of plant hormones, trigger cell division, stem elongation and differentiation into roots, shoots and leaves. The herbicide 2,4-D is a synthetic auxin that kills broadleaf plants, such as dandelions or pigweed, by forcing them to grow to the point of exhaustion.
Asked for his favorite example of a plant hormone, Corey S. Westfall brings up its chemical defense systems. Westfall, a graduate student in the Jez laboratory, who together with Chloe Zubieta, PhD, a staff scientist at the European Synchrotron Radiation Facility did most of the work on the research.
Walking through a public park in St. Louis near WUSTL, Westfall often sees oak leaves with brown spots on them. The spots are cells that have deliberately committed cell suicide to deny water and nutrients to a pathogen that landed in the center of the spot. This form of self-sterilization is triggered by the plant hormone salicylic acid.
Westfall also mentions the jasmonates, which cause plants to secrete compounds such as tannins that discourage herbivores. Tannins are toxic to insects because they bind to salivary proteins and inactivate them. So insects that ingest lots of tannins fail to gain weight and may eventually die.
A little more, a little less
Hormones, in other words, allow plants to respond quickly and sometimes dramatically to developmental cues and environmental stresses. But in order to respond appropriately, plants have to be able to sensitively control the level and activity of the hormone molecules.
The Science paper reveals a key control mechanism: a family of enzymes that attach amino acids to hormone molecules to turn the hormones on or off. Depending on the hormone and the amino acid, the reaction can activate the hormone, put it in storage or mark it for destruction.
For example, in the model plant, thale cress, fewer than 5 percent of the auxins are found in the active free-form. Most are conjugated (attached) to amino acids and inactive, constituting a pool of molecules that can be quickly converted to the active free form.
The attachment of amino acids is catalyzed by a large family of enzymes (proteins) called the GH3s, which probably originated 400 million years ago, before the evolution of land plants. The genes diversified over time: there are only a few in mosses, but 19 in thale cress and more than 100 in total.
“Nature finds things that works and sticks with them,” Jez says. The GH3s, he says, are a remarkable example of gene family expansion to suit multiple purposes.
A swiveling hormone modification machine
The first GH3 gene — from soybean — was sequenced in 1984. But gene (or protein) sequences reveal little about what proteins do and how they do it. To understand function, the scientists had to figure out how these enzymes, which start out as long necklaces of amino acids, fold into knobbly globules with protective indentations for chemical reactions.
Unfortunately, protein folding is a notoriously hard problem, one as yet beyond the reach of computer calculations at least as a matter of routine. So most protein structures are still solved by the time-intensive process of crystallizing the protein and bombarding the crystal with X-rays to locate the atoms within it. Both the Jez lab and the Structural Biology Group at European Synchrotron Radiation Facility specialize in protein crystallization.
By good fortune, the scientists were able to freeze the enzymes in two different conformations. This information and that gleaned by mutating the amino acids lining the enzyme’s active site let them piece together what the enzymes were doing.
It turned out that the GH3 enzymes, which fold into a shape called a hammer and anvil, cataylze a two-step chemical reaction. In the first step, the enzyme’s active site is open allowing ATP (adenosine triphosphate, the cell’s energy storage molecule) and the free acid form of the plant hormone to enter.
Once the molecules are bound, the enzyme strips phosphate groups off the ATP molecule to form AMP and sticks the AMP onto an “activated” form of the hormone, a reaction called adenylation.
Adenylation triggers part of the enzyme to rotate over the active site, preparing it to catalyze the second reaction, in which an amino acid is snapped onto the hormone molecule. This is called a transferase reaction.
“After you pop off the two phosphates,” Jez says, “the top of the molecule ratchets in and sets up a completely different active site. We were lucky enough to capture that crystallographically because we caught the enzyme in both positions.”
The same basic two-step reaction can either activate or inactivate a hormone molecule. Addition of the amino acid isoleucine to a jasmonate, for example, makes the jasmonate hormone bioactive. On the other hand addition of the amino acid aspartate to the auxin known as IAA marks it for destruction.
This is the first time any GH3 structure has been solved.
Plant breeding in a hurry
Understanding the powerful plant hormone systems will give scientists a much faster and more targeted way to breed and domesticate plant species, speed that will be needed to keep up with the rapid shift of plant growing zones.
Plant hormones, like animal hormones, typically affect the transcription of many genes and so have multiple effects, some desirable and others undesirable. But GH3 mutants provide a tantalizing glimpse of what might be possible: some are resistant to bacterial pathogens, others to fungal pathogens and some are exceptionally drought tolerant.
Westfall mentions that in 2003, a scientist at Purdue University figured out that a corn strain that had a short stalk but normal ears and tassels had a mutation that interferes with the flow of the hormone auxin in the plant.
Because the plants are so much smaller, they are relatively drought resistant and might be able to grow in India, where North American corn varieties cannot survive. Similar high-yield dwarf varieties might prevent famine in areas of the world where many people are at risk of starvation.
Diana Lutz | EurekAlert!
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
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
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They are two of the world’s biggest energy challenges: clean fuel for transportation and grid-scale energy storage. But in two studies published in the journals Science Advances and Nature Communications, a team of engineers describe their development of new technologies to take them on.
Hydrogen fuel has long been touted as a clean alternative to gasoline. Automakers began offering hydrogen-powered cars to American consumers last year, but only a handful have sold, mainly because hydrogen refueling stations are few and far between. “Millions of cars could be powered by clean hydrogen fuel if it were cheap and widely available,” said Yi Cui, associate professor of materials science and engineering at Stanford.
Unlike gasoline-powered vehicles, which emit carbon dioxide, hydrogen cars themselves are emissions free. Making hydrogen fuel, however, is not emission free: Today, making most hydrogen fuel involves natural gas in a process that releases carbon dioxide into the atmosphere.
To address the problem, Cui and his colleagues have focused on photovoltaic water splitting. This emerging technology consists of a solar-powered electrode immersed in water. When sunlight hits the electrode, it generates an electric current that splits the water into its constituent parts, hydrogen and oxygen.
Finding an affordable way to produce clean hydrogen from water has been a challenge. Conventional solar electrodes made of silicon quickly corrode when exposed to oxygen, a key byproduct of water splitting. Several research teams have reduced corrosion by coating the silicon with iridium and other precious metals.
Writing in the June 17 edition of Sciences Advances, Cui and his colleagues presented a new approach using bismuth vanadate, an inexpensive compound that absorbs sunlight and generates modest amounts of electricity. “Bismuth vanadate has been widely regarded as a promising material for photoelectrochemical water splitting, in part because of its low cost and high stability against corrosion,” said Cui, who is also an associate professor of photon science at SLAC National Accelerator Laboratory. “However, the performance of this material remains well below its theoretical solar-to-hydrogen conversion efficiency.”
Bismuth vanadate absorbs light but is a poor conductor of electricity. To carry a current, a solar cell made of bismuth vanadate must be sliced very thin, 200 nanometers or less, making it virtually transparent. As a result, visible light that could be used to generate electricity simply passes through the cell. To capture sunlight before it escapes, Cui’s team turned to nanotechnology. The researchers created microscopic arrays containing thousands of silicon nanocones, each about 600 nanometers tall. “Nanocone structures have shown a promising light-trapping capability over a broad range of wavelengths,” Cui explained. “Each cone is optimally shaped to capture sunlight that would otherwise pass through the thin solar cell.”
In the experiment, Cui and his colleagues deposited the nanocone arrays on a thin film of bismuth vanadate. Both layers were then placed on a solar cell made of perovskite, another promising photovoltaic material. When submerged, the three-layer tandem device immediately began splitting water at a solar-to-hydrogen conversion efficiency of 6.2 percent, already matching the theoretical maximum rate for a bismuth vanadate cell. “The tandem solar cell continued generating hydrogen for more than 10 hours, an indication of good stability,” said Cui, a principal investigator at the Stanford Institute for Materials and Energy Sciences. “Although the efficiency we demonstrated was only 6.2 percent, our tandem device has room for significant improvement in the future.”
In a second study published in the June 6 edition of Nature Communications, Cui and Shougo Higashi, a visiting scientist from Toyota Central R&D Labs Inc., proposed a new battery design that could help solve the problem of grid-scale energy storage. “Solar and wind farms should be able to provide around-the-clock energy for the electric grid, even when there’s no sunlight or wind,” Cui said. “That will require inexpensive batteries and other low-cost technologies big enough to store surplus clean energy for use on demand.”
In the study, Cui, Higashi and their co-workers designed a novel battery with electrodes made of zinc and nickel, inexpensive metals with the potential for grid-scale storage.
A variety of zinc-metal batteries are available commercially, but few are rechargeable, because of tiny fibers called dendrites that form on the zinc electrode during charging. Theses dendrites can grow until they finally reach the nickel electrode, causing the battery to short circuit and fail.
The research team solved the dendrite problem by simply redesigning the battery. Instead of having the zinc and nickel electrodes face one another, as in a conventional battery, the researchers separated them with a plastic insulator and wrapped a carbon insulator around the edges of the zinc electrode. “With our design, zinc ions are reduced and deposited on the exposed back surface of the zinc electrode during charging,” said Higashi, lead author of the study. “Therefore, even if zinc dendrites form, they will grow away from the nickel electrode and will not short the battery.”
To demonstrate stability, the researchers successfully charged and discharged the battery more than 800 times without shorting. “Our design is very simple and could be applied to a wide range of metal batteries,” Cui said.
Other co-authors of the Nature Communications study, “Avoiding short circuits from zinc metal dendrites in anode by backside-plating configuration,” are Seok Woo Lee and Jang Soo Lee of Stanford, and Kensuke Takechi of Toyota Central R&D Labs Inc. Four lead authors contributed equally to the Science Advances study, “Efficient solar-driven water splitting by nanocone BiVO4-perovskite tandem cells”: Yongcai Qiu, Wei Liu and Wei Chen of Stanford, and Wei Chen of Huazhong University. Other authors are Guangmin Zhou, Po-Chun Hsu, Rufan Zhang and Zheng Liang of Stanford; and Shoushan Fan and Yuegang Zhang of Tsinghua University. Support was provided by the U.S. Department of Energy, Stanford’s Global Climate and Energy Project, the National Natural Science Foundation of China and the Natural Science Foundation of Jiangsu Province in China. | <urn:uuid:50177b2f-40cb-49a6-8606-bc38d46cc435> | 4.4375 | 1,350 | News (Org.) | Science & Tech. | 26.926591 | 95,622,144 |
Warmer temperatures resulting from climate change may be causing longer growing seasons and a more intense release of pollen.
They absorb harmful carbon dioxide, turning it into stone.
What will historians say a century from now, if they still exist? That the most intelligent known species in the universe lost its mind.
The Bulletin of the Atomic Scientists sees increased threats to global survival from nuclear weapons and climate change—and President Trump.
Before his election, Donald Trump promised a new age for coal. But so far, the industry’s gains appear to be temporary, and its future remains bleak.
Studies show the untested technofix that would allow continued use of fossil fuels "could simultaneously benefit one region to the detriment of another.”
The country is the only major one in the world where damage to the climate is worsening as the population becomes poorer.
But the alliance says it won't be able to achieve necessary cuts in greenhouse gas emissions without efforts at the federal level.
The organization expects a global rise of 3 degrees Celsius by 2100, even if countries cut their greenhouse gas emissions as promised in 2015. | <urn:uuid:d9989b55-a152-4f4c-8b4f-71ff1329896a> | 2.890625 | 227 | Content Listing | Science & Tech. | 41.949886 | 95,622,168 |
In 1975 the Canadian ecologist and population activist tỷ lệ cá độ bóng đá introduced to the world a concept he called the "Demotechnic Index". It is the ratio of the amount of all technological energy a person uses in a day (energy from oil, gas, coal, hydro and nuclear power) over the average amount of energy they get in a day from the food they eat.
This article examines the state of the world in terms of that index, which I have taken the liberty of renaming the Thermodynamic Footprint or TF. I did that to make the term a little more accessible, and also in the spirit of the times - many of the people who read this will already be familiar with concepts like the Carbon Footprint and the Ecological Footprint.
The TF is intended to measure the impact we are having on the planet as the result of our use of technological energy. It also allows us to measure the change in our impact over time.
The TF is really a measure of human activity. All human activity is made possible though our use of energy, and our energy-driven activity is what alters the planet's physical, biological and chemical makeup - through mining, manufacturing, construction, habitat alterations, and the generation of wastes such as carbon dioxide, garbage and other pollution.
Because of this, our energy use is the best available proxy or representative for our overall impact on the planet. TF should therefore be understood as a measure of the impact we are having on (or damage we are doing to) our planet's life-support systems.
The Thermodynamic Footprint is the ratio of all the energy a person normally uses in a period of time, over the amount of energy they generate within their bodies from food. The "energy we normally use" includes fossil fuels and non-fuel generated electricity from hydro, nuclear and renewable sources such as wind and solar power. It includes both our own direct energy use and our individual share of all the energy society uses to create and maintain the world we live in.
The result is a number, expressed in units I call Human Equivalents or HE. The number describes how many times a person's environmental impact is multiplied by their technological energy consumption. If someone used no additional energy beyond the food they ate, their TF value would be 1 HE. If their TF is 2 HE, it means they have twice the impact on their environment as someone who used no additional energy. Someone with a TF of 10 HE has the same impact as ten people without energy assistance..
How is the TF Calculated?
The TF calculation begins with the amount of technological energy a person uses. This is commonly called "primary energy", and can be expressed in terms of electricity (watt-hours) or oil equivalents (expresses as "tonnes of oil equivalent" or TOE). Although thermal and electrical energy are not completely comparable, data sources such as the BP Statistical Review of World Energy provide standard factors that allow us to convert them all to a common basis. This number is then converted into the number of watts of power a person uses, which becomes the numerator of the TF.
The denominator of the TF ratio is the amount of power a person gets from the food they eat. In order to make the calculations a little simpler, a standard value of 125 watts is used. This value is also added to the numerator, so that if a person used no additional primary energy, their TF would be exactly 1.
If a person used no primary energy at all (like an ancient hunter-gatherer) their TF would be calculated as (0+125) / 125 = 1 HE
If a person's share of primary energy is 1250 watts their TF would be calculated as (1250+125) / 125 = 11 HE
A Basic Assumption
The core assumption of this approach is that all energy use creates an environmental or ecological impact.
While we are used to thinking of the impact of the energy sources themselves (for example, the CO2 and other pollution from burning fossil fuels; radioactive contamination from nuclear reactors; the mountaintop damage of coal mining; etc.) the impact of energy goes far beyond those initial effects. Energy enables all human activities, from agriculture to city-building, from dredging waterways to digging mines. Every human activity contributes to a web of direct and indirect environmental impacts that are independent of the source of the energy that is used in the activity.
What about other forms of energy?
Humans were already using a substantial amount of non-food energy well before 1800. Even before the discovery of agriculture some 10,000 years ago, our ancestors were already using firewood and other biofuels, oxen, horses, donkeys, yaks, dogs, etc. to do some of the work that had to be done. If we count all of the energy (and CO2) produced by biomass fuels and and draft animals, that would seem to add quite a lot to the human footprint.
However, the TF deliberately omits these sources of energy from the calculation and focuses solely on our use of technological primary energy sources. There are several reasons for this.
As a note, I do consider the pre-industrial sources of environmental damage like desertification and deforestation below. They are just not included directly in the TF calculation.
The data sources include the BP Statistical Review of World Energy 2012 and the World Bank's database of World Development Indicators.
First, here is the Thermodynamic Footprint of a single "average" world citizen at since 1800:
This technique also lets us determine how the Thermodynamic Footprint of nations has changed over time:
The Human Equivalent
The unit of the Human Equivalent or HE is similar to the concept of the "tỷ lệ cá độ bóng đáenergy slave". Each of us represents the operation of some quantity of primary energy within our environment. That energy (plus the food an individual consumes) represents the work of a number of "human equivalents", a number that is given by our Thermodynamic Footprint.
World Thermodynamic Footprint Since 1800
The next graph may be the most interesting. By multiplying the average global TF figure by the actual world population, we can find the "Human Equivalent" population of the world over time. This value reflects both our increasing energy consumption and our growing world population. It is a measure of the increasing planetary impact of the combined growth in our technology, activity and numbers.
Of course, our activity is not spread out evenly across the planet. Some areas see very little human activity, while others have quite a lot. If we estimate that one third of all the world's land is used by humans in one way or another, this brings the average HE density of the areas that are subject to human impact up to 8000 human equivalents per square mile. This is just about half the the population density of Hong Kong - living and working on every habitable square mile of the planet.
I = PAT
The famous equation "I = PAT" was introduced by Paul Ehrlich and John Holdren in the 1970s to express human environmental impact. In it, the impact (I) is calculated as our population (P) times our individual level of activity (A) times a technological multiplier (T). While we can measure P directly, finding good representatives for A or T (or for the combination of A x T) is quite difficult.
As Jack Vallentyne noticed over 35 years ago, the Thermodynamic Footprint is a very good proxy for that elusive "AT" term. By using it this way we can determine that humanity today is having 135 times the impact on the planet that we had just 200 years ago.
The Thermodynamic Footprint, expressed in Human Equivalents, quantifies in general terms the amount of damage that our technological activity is causing to the planet's life-support systems. This activity, driven by the energy we use in our daily lives, causes as much damage to the planetary systems we depend on as 135 billion people would if they were living in their raw human state, as hunter-gatherers.
It is estimated that there were about 5 million people living on the planet just before the invention of agriculture 10,000 years ago. Modern human civilization today has about 27,000 times the impact on the planet as did our ancestors of that time.
In the face of this degree of pressure, it is no wonder that our activity is damaging the world's atmosphere, geology, water chemistry and living ecology as profoundly as it is today. The 64 trillion dollar question is, "How close are we to the point where the Earth's systems can no longer cope with these changes, and finally force us to cease and desist?"
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NAMEdelch, wdelch, mvdelch, mvwdelch - delete character under the cursor in a curses window
SYNOPSIS#include <curses.h> int delch(void); int wdelch(WINDOW *win); int mvdelch(int y, int x); int mvwdelch(WINDOW *win, int y, int x);
DESCRIPTIONThese routines delete the character under the cursor; all characters to the right of the cursor on the same line are moved to the left one position and the last character on the line is filled with a blank. The cursor position does not change (after moving to y, x, if specified). (This does not imply use of the hardware delete character feature.)
RETURN VALUEAll routines return the integer ERR upon failure and an OK (SVr4 specifies only "an integer value other than ERR") upon successful completion. Functions with a "mv" prefix first perform a cursor movement using wmove, and return an error if the position is outside the window, or if the window pointer is null.
NOTESNote that delch, mvdelch, and mvwdelch may be macros.
PORTABILITYThese functions are described in the XSI Curses standard, Issue 4. The standard specifies that they return ERR on failure, but specifies no error conditions. | <urn:uuid:f56e4f13-7655-4de1-973d-d7927a8d5735> | 2.53125 | 296 | Documentation | Software Dev. | 46.758095 | 95,622,192 |
2 irrational number
2 irrational number
Suppose for the sake of contradiction that is rational. Then there are integers m’ and n’ with = m’/ n’.
By dividing both m’ and n’ by all the factors that are common to both, we obtain =m/n, for some integer m and n having no common factors. Since m/n= , m= n . Squaring both sides of this equation, we obtain m2=2n2, and therefore m2 is even.
If a and b are odd, then ab is odd. Since a conditional statement logically equivalent to its contrapositive. we may conclude that for any a and b, if ab not odd, then either a is not odd or b is not odd.
However, an integer is not odd if and only if it is even, and so for any a and b, if ab is even, m must be even.
This means that for some k, m=2k. Therefore, (2k) 2=2n2.
Simplifying this and canceling 2 from both sides, we obtain 2k2=n2. Therefore n2 is even.
The same argument that we have already used to show that n must be even, and so n=2j for some j.
We have shown that mand n are both divisible by 2. This contradicts the previous statement that mand n have no common factor. The assumption that is rational therefore it leads to a contradiction, and the conclusion is that is irrational: 2 irrational number
To Prove: For every three positive integers i, j, and n, if i*j = n, then I ≤ or j ≤.
The statement we wish to prove of the general form “for every x, if p(x) then q(x).” For each x. The statement “if p(x) then q(x)” logically equivalent to “if not p(x) then not q(x).” and therefore the statement we want to prove equivalent to this: For any positive integer i, j and n, if it is not the case that i ≤ or j ≤ then i*j≠n.
if it is not true then i >and j>. A generally accepted fact from mathematical is that if a and b are the number with a> b, and c is a number >0, then ac>bc.
Applying this to the inequality i> with c=j, we obtain i*j > * j. since n>0, we know that >0, and we may apply the same fact again to the inequality j>, this time letting c=, to obtain j > =n. We now have i*j > j >n, and it follows that i*j ≠ n.
Hence, the proof is complete: 2 irrational number | <urn:uuid:f48da6af-9e06-49a0-b9dd-e8bfc9175d04> | 3.375 | 608 | Academic Writing | Science & Tech. | 82.64005 | 95,622,195 |
Team gives a microscopic quantum mechanical description of how light excites electrons in metals
University of Pittsburgh researchers have become the first to detect a fundamental particle of light-matter interaction in metals, the exciton. The team will publish its work online June 1 in Nature Physics.
Mankind has used reflection of light from a metal mirror on a daily basis for millennia, but the quantum mechanical magic behind this familiar phenomenon is only now being uncovered.
Physicists describe physical phenomena in terms of interactions between fields and particles, says lead author Hrvoje Petek, Pitt's Richard King Mellon Professor in the Department of Physics and Astronomy within Kenneth P. Dietrich School of Arts and Sciences. When light (an electromagnetic field) reflects from a metal mirror, it shakes the metal's free electrons (the particles), and the consequent acceleration of electrons creates a nearly perfect replica of the incident light (the reflection).
The classical theory of electromagnetism provides a good understanding of inputs and outputs of this process, but a microscopic quantum mechanical description of how the light excites the electrons is lacking.
Petek's team of experimental and theoretical physicists and chemists from the University of Pittsburgh and Institute of Physics in Zagreb, Croatia, report on how light and matter interact at the surface of a silver crystal. They observe, for the first time, an exciton in a metal.
Excitons, particles of light-matter interaction where light photons become transiently entangled with electrons in molecules and semiconductors, are known to be fundamentally important in processes such as plant photosynthesis and optical communications that are the basis for the Internet and cable TV. The optical and electronic properties of metals cause excitons to last no longer than approximately 100 attoseconds (0.1 quadrillionth of a second). Such short lifetimes make it difficult for scientists to study excitons in metals, but it also enables reflected light to be a nearly perfect replica of the incoming light.
Yet, Branko Gumhalter at the Institute of Physics predicted, and Petek and his team experimentally discovered, that the surface electrons of silver crystals can maintain the excitonic state more than 100 times longer than the bulk metal, enabling the excitons in metals to be experimentally captured by a newly developed multidimensional coherent spectroscopic technique.
The ability to detect excitons in metals sheds light on how light is converted to electrical and chemical energy in plants and solar cells, and in the future it may enable metals to function as active elements in optical communications. In other words, it may be possible to control how light is reflected from a metal.
The paper, "Transient Excitons at Metal Surfaces," will be published June 1 in the online edition of Nature Physics. The work was supported by a grant from the Division of Chemical Sciences, Geosciences, and Biosciences of the Office of Basic Energy Sciences of the U.S. Department of Energy.
Joseph Miksch | Eurek Alert!
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...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
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Convection occurs in ice-covered lakes if solar radiation warms near-surface water from the freezing point towards the temperature of maximal density. One effect of convective mixing may be to suspend non-motile phytoplankton in the upper water column, providing cells with enough light for growth during ice-covered periods. Observations of the diatom Aulacoseira baicalensis under the ice cover of Lake Baikal, Siberia, support the hypothesis that convective mixing causes net suspension of cells. This paper presents a theoretical examination of the conditions under which convective how fields can suspend algae in the photic zone of the upper water column. It is shown that the efficiency of algal suspension depends on the ratio of the still-water algal sinking rate, W-p, to convective updraft speed, W-u. The suspension efficiency is also shown to be affected by asymmetries in the flow field and night-time cessation of convection, but only if W-p and W-u are comparable in value. It is concluded that convection in Lake Baikal should be vigorous enough to increase the mixed-layer residence time of A.baicalensis from a few days to over a month, at least during years with thin snow cover.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below | <urn:uuid:8fd3ca34-1162-4d13-b400-835d453e9e54> | 3.15625 | 283 | Academic Writing | Science & Tech. | 30.375936 | 95,622,198 |
So far ranging and residence patterns amongst early hominins have been indirectly inferred from morphology, stone tool sourcing, comparison to living primates and phylogenetic models. An international team of researchers including Sandi Copeland, Vaughan Grimes and Michael Richards of the Max Planck Institute for Evolutionary Anthropology in Leipzig/Germany have now investigated landscape use in Australopithecus africanus (with fossils from sites dating between 2.8-2.0 million years ago) and Paranthropus robustus (with fossils from sites dating between 1.9-1.4 million years ago) from the Sterkfontein and Swartkrans cave sites in South Africa using strontium isotope analysis.
Skull of a Paranthropus robustus from Swartkrans Cave in South Africa. Darryl de Ruiter
This method helps identify the geological substrate on which an animal lived during tooth mineralization. The researchers show that a high proportion of small, but not large, hominin teeth had non-local strontium isotope compositions. Given the relatively high levels of sexual dimorphism in early hominins, the smaller teeth probably represent females, indicating that females were more likely than males to disperse from their natal (i.e. where they were born) groups. This is similar to the dispersal pattern found in chimpanzees, bonobos, and many human groups, but dissimilar to that of most gorillas and other primates. (Nature, June 2nd, 2011)
Established paleontological and archaeological techniques provide little tangible evidence for how early hominins used and moved across landscapes. For example, home range size has been estimated based on a rough correlation with body mass, and models of early hominin dispersal have relied on behaviors common among hominoids and presumed to be present in a common ancestor. “However, the highly uncertain nature of such reconstructions limits our understanding of early hominin ecology, biology, social structure, and evolution”, says Sandi Copeland of the Max Planck Institute for Evolutionary Anthropology.
Copeland and colleagues have now used a geochemical proxy, strontium isotope analysis of tooth enamel, to investigate early hominin landscape use. Strontium is ingested and incorporated in trace quantities into mammalian teeth. First, the researchers determined strontium isotopes in plant specimens that were collected within a 50 km radius of the Sterkfontein and Swartkrans caves in order to establish the background of biologically available strontium across the region. They then sampled a series of hominin tooth crowns by employing a relatively new method for measuring strontium isotopes in teeth that is called laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). This method is almost non-destructive as it leaves only tiny traces on the enamel surface. The researchers found that although there is no significant difference between the proportion of non-locals in P. robustus (36 %) and A. africanus (25 %), there are significant differences between subsets of hominins defined by tooth size.
“The strontium isotope data suggest differences in landscape use between males and females”, says Sandi Copeland and explains: “Because strontium was incorporated into the teeth before adulthood, when the hominins were probably travelling with their mothers, the data are unlikely to reflect differences in foraging areas between adult males and adult females. Rather, the strontium isotopes probably indicate that females preferentially moved away from residential groups”.
The hominins’ female but not male dispersal pattern is similar to the one found in chimpanzees, bonobos, and many human groups, but dissimilar to that of most gorillas and other primates. This suggests that early hominin social structure was not like that of gorillas in which one or few males dominate groups of females.
The small proportion of non-local large hominins could indicate that male australopiths had small home ranges, which would be surprising given that the evolution of bipedalism is commonly attributed to the need to move over large distances. The results could also imply that male australopiths preferred the types of resources found on dolomite landscapes. This study was the first to apply this method to early fossil hominins, and lays the groundwork for future studies of other fossil species, including Australopithecus and Paranthropus in East Africa, and later hominins belonging to our genus Homo.
The following institutions contributed to this study: Max Planck Institute für Evolutionary Anthropology, Leipzig, Germany; University of Colorado, Boulder, USA; Texas A&M University, College Station, USA; Oxford University, Oxford, UK; University of Cape Town, Cape Town, South Africa; University of Zurich, Zurich, Switzerland; Memorial University, St. John’s, Canada; University of British Columbia, Vancouver, Canada.
Original publication:Sandi R. Copeland, Matt Sponheimer, Darryl J. de Ruiter, Julia A. Lee-Thorp, Daryl Codron, Petrus J. le Roux, Vaughan Grimes & Michael P. Richards
Barbara Abrell | Max-Planck-Gesellschaft
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The study has determined GNTs are effective in helping doctors track stems cells through the body by making them 40 times better than standard contrast agents used in magnetic resonance imaging. Contrast agents help doctors spot signs of disease or damage in MR images.
Researchers at Rice and the Texas Heart Institute at St. Luke's Episcopal Hospital in Houston reported in the journal Biomaterials that mesenchymal stem cells drawn from pig bone marrow labeled with GNTs are easily spotted under MRI. The technique holds promise for tracking the progress of tagged cells as they travel through a patient's body.
Ultimately, the team hopes the magnetic properties of tagged stem cells will allow doctors to manipulate them in vivo and direct cells to specific locations -- in the heart, for instance -- where they can heal damaged tissue.
GNTs are carbon nanotubes that contain gadolinium, an element commonly used in designing contrast elements for use in MRI. Though toxic, gadolinium is chelated, or chemically bound, which makes it safer for injection into the body. But clinical agents like the gadolinium-based Magnevist cannot enter cells.
However, GNTs can. Invented in the lab of Rice chemistry professor Lon Wilson in 2005, the nanotubes sequester bundles of gadolinium ions, which enhance contrast in MRIs but cannot escape their carbon cages. This makes them biologically inert and safe for tagging cells from within.
The team found GNTs did not affect the stem cells' ability to differentiate into other types of cells or to self-renew, though work continues to characterize their ability to adhere to cell scaffolds under various conditions.
Lesa Tran, a fourth-year graduate student in Wilson's lab, was the primary author of the paper, and Wilson was corresponding author. Co-authors were Rice graduate student Ramkumar Krishnamurthy; Raja Muthupillai, a senior physicist at St. Luke's; and of the Texas Heart Institute: Maria da Graça Cabreira-Hansen, a research scientist; James Willerson, president and medical director; and Emerson Perin, medical director of the Stem Cell Center.
Primary funding for the project came from the $1 million NIH Challenge Grant, with additional funding by the National Science Foundation and the Robert A. Welch Foundation.
Read the abstract here: http://tinyurl.com/34fpb5m.
Download artwork here: http://www.media.rice.edu/images/media/NEWSRELS/1108_gadonanotube.jpg
Caption: Dark spots are aggregates of gadonanotubes (GNTs) in the cytoplasm of a mesenchymal stem cell. Tests show GNTs are highly effective for tagging and tracking stem cells through magnetic resonance imaging. (Credit: Lesa Tran/Rice University)
Located in Houston, Rice University is consistently ranked one of America's best teaching and research universities. Known for its "unconventional wisdom," Rice is distinguished by its: size -- 3,279 undergraduates and 2,277 graduate students; selectivity -- 12 applicants for each place in the freshman class; resources -- an undergraduate student-to-faculty ratio of 5-to-1; sixth largest endowment per student among American private research universities; residential college system, which builds communities that are both close-knit and diverse; and collaborative culture, which crosses disciplines, integrates teaching and research, and intermingles undergraduate and graduate work.
David Ruth | EurekAlert!
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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.
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The long and steady antennae, whose three outer segments are fused together and can therefore be poorly differentiated from each other, appear to consist of 5 segments. The compound eyes of the males are very large and hairy and are positioned very closely together on the top of the head. . The upper part of their facets eyes consists of large facets since the lower part consists of small individual eyes (Ocelli). The female Bibio clavipes have much smaller eyes than the males. Their eyes are pure compound eyes and are hairless.
The front wings are colourless but have dark markings on their edges. The females have a spike on the tibiae of their front legs which is used for digging.
|Bibio clavipes - Front view|
|The life span of Bibio clavipes is very short. This species is one of the few bibionids, which are active in September. Bibio clavipes feed on nectar and honeydew and do not sting. |
Bibio clavipes reproduce once a year. During mating season, partners come together in large swarms. Fertilization of the females starts in the air and is completed on the ground.
|Bibio clavipes - rear view|
|The females lay their eggs, singly or in groups of up to 3000, in humus-rich soil. The larvae develop in the upper humus layers of grasslands and forests, among fallen leaves and dead vegetation or near tree stumps. They are hairy in the early stages of development. These hairs later form spiky projections. |
The chest segments of the larvae are equipped with 10 pairs of invertebrate tracheae which supply the larvae with oxygen. The larvae can be very large. The larvae of Bibio clavipes are cold resistant and overwinter. They are herbivores but can also feed on carrion. They feed on both living and dead plants. At the end of their development, the larvae pupate in the soil. The pupae are equipped with breathing horns which lengths are limited.
|Due to their role as pollinators of early blooming fruit trees, Bibio clavipes are considered ecologically significant. The larvae make an important contribution to the formation of humus in the soil, but can also be harmful to plant roots in winter time or in dry seasons, especially if they occur en masse. |
|Description of images / photos|
Photography with Cameras
Nikon D3x, Nikon D300, Canon 50D
Image editing with Photoshop
|1. ||Bibio clavipes|
|2. ||Bibio clavipes - Top view|
|3. ||Bibio clavipes - Front view|
|4. ||Bibio clavipes - rear view|
|bibio clavipes (2)|
|bibio clavipes images (1)|
|Bibionidae Life span (1)|
|bibio tancrei (1)|
|bibio genus bibionidae images (1)|
|bibio species pictures (1)| | <urn:uuid:3e8c0a82-0144-4963-8659-28e9c478207c> | 3.515625 | 657 | Knowledge Article | Science & Tech. | 52.477363 | 95,622,227 |
Forget roof-mounted solar panels that turn part of your home into a clean energy source. The new phase of solar operates under more of a “go big or go home” angle. That’s because a new solar paint can make every exterior wall of your house a source of clean, renewable energy. Futurism reports that a team of researchers at the Royal Melbourne Institute of Technology in Australia has created a paint that can generate hydrogen fuel from sunlight and moist air. Not quite ready for the shelves at Home Depot, the team does anticipate the paint to be available for sale within the next five years.
So whether it’s a gorgeous, sunny day or humid as can be, your house would be a source of clean energy that could power all your appliances, climate control, and lights.
The process is simple: The paint is made of titanium oxide and a new compound, synthetic molybdenum-sulphide. That mouthful mimics the properties of the silica gel bags that come with new pairs of sneakers and other products to wick away moisture.
Synthetic molybdenum-sulphide absorbs solar energy from the air before splitting it into hydrogen and oxygen. The hydrogen can then be collected in fuel cells for a home, or even to power a car, truck, boat, or ATV. Is this not the coolest news?
“We found that mixing the compound with titanium oxide particles leads to a sunlight-absorbing paint that produces hydrogen fuel from solar energy and moist air,” said the group’s lead researcher, Dr. Torben Daeneke. “Titanium oxide is the white pigment that is already commonly used in wall paint, meaning that the simple addition of the new material can convert a brick wall into energy harvesting and fuel production real estate."
“Our new development has a big range of advantages,” he added. “There’s no need for clean or filtered water to feed the system. Any place that has water vapor in the air, even remote areas far from water, can produce fuel.” Plus, the paint would be significantly cheaper than solar panels, Daeneke told Inverse.
Daeneke’s colleague, Distinguished Professor Kourosh Kalantar-zadeh, echoed the lead researcher’s sentiments, noting that hydrogen is the cleanest energy source around and can be used as a perfect replacement for fossil fuels.
“This system can also be used in very dry but hot climates near oceans,” Kalantar-zadeh said. “The sea water is evaporated by the hot sunlight and the vapor can then be absorbed to produce fuel. This is an extraordinary concept – making fuel from the sun and water vapor in the air.”
The research team’s results were published as "Surface Water Dependent Properties of Sulfur Rich Molybdenum Sulphides – Electrolyteless Gas Phase Water Splitting” in ACS Nano, a journal of the American Chemical Society. If your house (or fence, garage, or birdhouse) is almost ready for a fresh coat of paint, you may want to hold off just a few more years, so that when you do pick out a fresh color, it’s one that will also provide all the energy your dwelling requires.
Sweden's aggressive target of generating over 40 terawatt-hours of renewable energy by 2030 could be reached nearly a decade early. A massive amount of wind power projects could hit a snag in market value with subsidies, but SWEA could push to close those up by the end of the year.
It's challenging and laborious to detect this bacteria that decimates bee populations, so an apiary inspector trained a dog to do it. They're amazing.
New technologies means that instead of sucking power off the energy grid, buildings can feed back into it, powering other buildings and even cars.
A sixth-grader in Massachusetts has begun developing a robot that's able to detect microplastics in our ocean after wanting to make a difference at the Boston Harbor. Her ultimate goal is to create a way to also pick up trash and cut costs in the process. | <urn:uuid:7fc70917-47c5-48dd-ac70-7e13420d6df4> | 2.875 | 879 | News Article | Science & Tech. | 47.185281 | 95,622,290 |
From an engineering point of view, one all-purpose model of pump on the surface of a cell should suffice to keep these levels constant: When the concentration of a nutrient, say, sugar, drops inside the cell, the pump mechanism could simply go into higher gear until the sugar levels are back to normal.
Yet strangely enough, such cells let in their nutrients using two types of pump: One is active in "good times," when a particular nutrient is abundant in the cell's environment; the other is a "bad-times" pump that springs into action only when the nutrient becomes scarce. Why does the cell need this dual mechanism?
A new Weizmann Institute study, reported in Science, might provide the answer. The research was conducted in the lab of Prof. Naama Barkai of the Molecular Genetics Department by postdoctoral fellow Dr. Sagi Levy and graduate student Moshe Kafri with lab technician Miri Carmi.
It had been known for a while that when the levels of phosphate or zinc drop in the surroundings of a yeast cell, the number of "bad-times" pumps on the cell surface soars up to a hundred-fold. When phosphate or zinc becomes abundant again, the "bad-times" pumps withdraw while the "good-times" pumps return to the cell surface in large numbers.
In their new study, the scientists discovered that cells which repress their "bad-times" pumps when a nutrient is abundant were much more efficient at preparing for starvation and at recovering afterwards than the cells that had been genetically engineered to avoid this repression. The conclusion: The "good-times" pumps apparently serve as a signaling mechanism that warns the yeast cell of approaching starvation. Such advance warning gives the cell more time to store up on the scarce nutrient; the thorough preparation also helps the cell to start growing faster once starvation is over.
Thus, the dual-pump system appears to be part of a regulatory mechanism that allows the cell to deal effectively with fluctuations in nutrient supply. This clever mechanism offers the cell survival advantages that could not be provided by just one type of pump.
If these findings prove to be applicable to human cells, they could explain how our bodies maintain adequate levels of various nutrients in tissues and organs. Understanding the dual-pump regulation could be crucial because it might be defective in various metabolic disorders.
Prof. Naama Barkai's research is supported by the Helen and Martin Kimmel Award for Innovative Investigation; the Jeanne and Joseph Nissim Foundation for Life Sciences Research; the Carolito Stiftung; Lorna Greenberg Scherzer, Canada; the estate of John Hunter; the Minna James Heineman Stiftung; the European Research Council; and the estate of Hilda Jacoby-Schaerf. Prof. Barkai is the incumbent of the Lorna Greenberg Scherzer Professorial Chair.
The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to 2,700 scientists, students, technicians and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials and developing new strategies for protecting the environment.
Weizmann Institute news releases are posted on the World Wide Web at http://wis-wander.weizmann.ac.il, and are also available at http://www.eurekalert.org.
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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...
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|Scientific Name:||Beringraja binoculata (Girard, 1855)|
Dipturus binoculata (Girard, 1855)
Raja binoculata Girard, 1855
|Taxonomic Source(s):||Eschmeyer, W.N. (ed.). 2015. Catalog of Fishes. Updated 2 July 2015. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 2 July 2015).|
|Taxonomic Notes:||Ishihara et al. (2012) established the new genus Beringraja for the two species B. binoculata (previously Raja binoculata Girard, 1855) and B. pulchra (previously Raja pulchra Liu 1932).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Farrugia, T.J., Goldman, K.J., King, J.R. & Ormseth, O.A.|
|Reviewer(s):||Barnett, L.A.K. & Lawson, J.|
|Contributor(s):||Ellis, J.R., Dulvy, N.K. & Jang, J.J.|
|Facilitator/Compiler(s):||Kyne, P.M., Lawson, J. & Walls, R.H.L.|
The Big Skate (Beringraja binoculata, formerly Raja binoculata) is a large-bodied demersal skate that occurs primarily on soft-sediment habitats in coastal waters on the continental shelf in the Northeast Pacific and the Eastern Central Pacific, from northern Baja California to Alaska. They are one of the largest species of skate and, as with the Common Skate (Dipturus batis) and Barndoor Skate (Dipturus laevis), may be susceptible to overfishing given their large body size. The Big Skate may be one of the most fecund elasmobranchs and has an estimated generation length of 14.25 years. However, life-history traits differ between regions. This species is taken in commercial and recreational fisheries, and is monitored through formal stock assessments throughout much of its range. Indices of relative abundance of the populations found off British Columbia, Canada and in the Gulf of Alaska have remained relatively stable over time. On the west coast of the United States (Washington, Oregon and California), this species is managed under the federal Groundfish Fishery Management Plan. Given that available stock assessments indicate that populations of the Big Skate are stable, and that this species is managed throughout much of its range, this species is assessed as Least Concern.
|Previously published Red List assessments:|
The Big Skate is found along the western coast of North America, from the Gulf of California to the Bering Sea (Walford 1935, Roedel and Ripley 1950).
Native:Canada (British Columbia); Mexico (Baja California); United States (Alaska, Aleutian Is., California, Oregon, Washington)
|FAO Marine Fishing Areas:|
Pacific – eastern central; Pacific – northeast
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population trend is estimated to be stable based on stock assessments from British Columbia, Canada and the Aleutian Islands (AI), Eastern Bering Sea (EBS), and Gulf of Alaska (GOA), in the United States. In Washington, Oregon, California, United States and Baja California, Mexico, no species-specific stock assessments are available and thus the population trend is unknown. In Californian waters the species is one of the three most important skates in the fisheries (Roedel and Ripley 1950, Martin and Zorzi 1993) and is caught incidentally by trawl, longline and trammel net gear (Zeiner and Wolf 1993). Martin and Zorzi (1993) analysed trends in the commercial landings of skates from 1916-1990 and reported that annual landings of Rajidae species ranged from 22.9 to 286.3 tonnes. Since 1916, skates have constituted 11.8% of the total weight of elasmobranchs landed (ranging from 1.9 to 89.5% annually). The skates that are landed in the Californian fishery are mostly juveniles (Roedel and Ripley 1950, Martin and Zorzi 1993), with larger individuals being discarded.|
A formal stock assessment for the Big Skate in British Columbia, Canada was published by Fisheries and Oceans Canada. The assessment concluded that the historical (1996-2011) levels of removal have had no significant impact on Big Skate abundance in the region based on available trawl and longline survey data (King et al. 2015).
Recent stock assessment data exist for the AI, EBS, and GOA and are based on bottom trawl surveys conducted by the U.S. National Marine Fisheries Service. Biomass of the Big Skate for the entire BSAI area (EBS shelf, EBS slope, AI) was 1,692 t in 2002, 1,373 t in 2004, 4,081 t in 2010 and 1,356 t in 2012 (Ormseth 2014a). In the GOA, the Big Skate is managed distinctly from the Longnose Skate (Raja rhina) and "Other Skates". Biomass of the Big Skate across the entire GOA has remained relatively stable at ~50,000 t since the 1990s , but a dramatic decline in biomass of the Big Skate has been recorded in the Central GOA since 2003 (Ormseth 2014b). Despite this area-specific decline the Big Skate is not considered to be overfished based on GOA-wide biomass estimates (Ormseth 2014b).
|Current Population Trend:||Stable|
|Habitat and Ecology:||The Big Skate is most common in soft-sediment habitats in coastal waters on the continental shelf (Bizzarro et al. 2014, Farrugia et al. in press 2016), although they have also been observed associating with hard substrates (Steinet al. 1992). They are most common at depths of less than 200 m (Day and Pearcy 1968, Love et al. 2005, Ormseth 2011), although they have been found to depths of 800 m (Martin and Zorzi 1993). In the GOA this species is the most commonly encountered species of skate in the inshore continental shelf waters at 100–200 m depth, and is most abundant in the central and western areas of the GOA (Ormseth 2014b; Bizzarro et al. 2014). Similarly, in central California, the Big Skate is aggregated on the continental shelf near the coast (Bizzarro et al. 2014).|
Despite being a demersal species that is considered to be relatively sedentary, the Big Skate is capable of large movements. For example, in British Columbia, a study revealed that ~75% of tagged individuals were recaptured within 21 km of the tagging locations, but 15 of the tagged individuals (0.1%) moved over 1,000 km (King and McFarlane 2010). In the Gulf of Alaska, satellite tags showed that over a one-year period six of the twelve tagged individuals observed in this study moved over 100 km, and a single individual moved 2,000 km (Farrugia et al. in press 2016).
The Big Skate attains a maximum total length (TL) of about 290 cm (McFarlane and King 2006), although specimens over 180 cm TL (90 kg) are unusual (Martin and Zorzi 1993), especially outside of British Columbia waters. Length-weight relationships (Zeiner and Wolf 1993, Downs and Cheng 2013), age and growth parameters have been established in California (Zeiner and Wolf 1993), British Columbia (McFarlane and King, 2006), and the Gulf of Alaska (Gburski et al. 2007, Ebert et al. 2008). In California and the Gulf of Alaska, big skates reach about 250 cm TL and live to about 15 years, whereas in British Columbia they can grow up to 290 TL cm and live to 26 years. It is important to note that age estimates are based on an unvalidated method and geographic differences in size or age may reflect differences in sampling or ageing criteria. Age and size at maturity also differs between regions. In the Gulf of Alaska, females big skates reach 50% maturity at 150 cm TL (10 years) and at 120 cm TL (7 years) for males (Gburski et al. 2007, Ebert et al. 2008). In British Columbia, females reach 50% maturity at 90 cm TL (8 years) and at 72 cm TL (6 years) for males (McFarlane and King 2006). The Big Skate is oviparous and deposits egg cases on the sea floor that have embryos that develop in 6 to 20 months, depending on water temperature (Hoff 2007). Fecundity estimates are difficult to obtain because the Big Skate is one of only two skates to have more than one embryo per egg case. Aquarium observations have shown that the most common number of embryos per egg case is two (Chiquillo et al. 2014), but the range is from 1 to 7 (DeLacy and Chapman 1935, Hitz 1964). The number of egg cases that can be produced per female each year is uncertain, but observations in aquaria indicate that females can deposit over 350 egg cases per year (Ebert et al. 2008). This indicates that big skates may be one of the most fecund elasmobranchs. In the wild, only a few areas where egg cases are deposited have been observed, in Oregon (Hitz 1964) and the Gulf of Alaska (Thomas Farrugia, pers. obs. 2014), in which egg cases can reach densities of 7.5 egg cases per 100 m². Estimates of generation length range from 11.5 to 17 years (Zeiner and Wolf 1993, McFarlane and King 2006) with an average of 14.25 years.
|Generation Length (years):||11.5-17|
|Use and Trade:||This species is utilized for its meat.|
Commercial and recreational fisheries are most likely the main threat to this species. In Californian waters the species was one of the three most important rajids in commercial and recreational fisheries along with the California Skate (Dipturus inornata) and Longnose Skate (Raja rhina; Roedel and Ripley 1950, Martin and Zorzi 1993) and is landed as bycatch from trawlers, longline and trammel nets (Zeiner and Wolf 1993, California Department of Fish and Wildlife 2015). Martin and Zorzi (1993) analysed trends in the commercial landings of skates from 1916-1990 and reported that annual landings of Rajidae ranged from 22.9-286.3 t. The skates that are landed in the Californian fishery have tended to be juvenile fish (Roedel and Ripley 1950, Martin and Zorzi 1993), with larger individuals being discarded.
In British Columbian and Alaskan waters ongoing direct and indirect take of the Big Skate occurs. Since the global market for skates is increasing, there is likely going to be a increasing demand for skate fisheries in the Northeast Pacific (Farrugia et al. in press 2016).
Stock assessments are used to inform status and management of fisheries throughout much of the range of the Big Skate. On the west coast of the United States (Washington, Oregon and California), groundfisheries are managed by a federal Groundfish Fishery Management Plan. This species is one of the six shark and ray species that are managed under a Fishery Management Plan (PFMC 2014). In the Gulf of Alaska, an Allowable Biological Catch (ABC) based on fishery-independent biomass estimates and natural mortality estimates is generated annually (Ormseth 2014a,b). Additionally, in California, a network of 29 marine protected areas (MPAs) were implemented in 2007 under California's Marine Life Protection Act, representing approximately 204 square miles (~18%) of state waters in the central coast region (California Department of Fish and Wildlife 2015). Due to these MPAs, most trawlers are restricted to operating in deeper waters, and only in central and northern California. As a result, fishing effort in the California trawl fishery has been reduced, and southern California is largely closed to trawl fishing.
In British Columbia, Canada, catch limits are set based on mean historic catch with consideration of estimates of trends and Maximum Sustainable Yield is estimated (King et al. 2015).
Bizzarro, J.J., Broms, K.M., Logsdon, M., Ebert, D.A., Yoklavich, M.M., Kuhnz, L., and Summers, A.P. 2014. Spatial segregation in eastern North Pacific skate assemblages. PLoS ONE 9(10): e109907.
California Department of Fish and Wildlife. 2015. California's Marine Protected Area (MPA) Network. Monterey, CA Available at: http://www.dfg.ca.gov/marine/mpa/mpa_summary.asp. (Accessed: 27/01/2015).
Chiquillo, K.E., Ebert, D.A., Slager, C.J. and Crow, K.D. 2014. The secret of the mermaid’s purse: Phylogenetic affinities within the Rajidae and the evolution of a novel reproductive strategy in skates. Molecular Phylogenetics and Evolution 75: 245–251.
Day, D.S. and Pearcy, W.G. 1968. Species associations of benthic fishes on the continental shelf and slope off Oregon. Journal of the Fisheries Research Board of Canada 25(12): 2665–2675.
DeLacy, A.C. and Chapman, W.M. 1935. Notes on some elasmobranchs of Puget Sound, with descriptions of their egg cases. Copeia 1935(2): 63–67.
Downs, D.E. and Cheng, Y.W. 2013. Length–Length and Width–Length Conversion of Longnose Skate and Big Skate Off the Pacific Coast: Implications for the Choice of Alternative Measurement Units in Fisheries Stock Assessment. North American Journal of Fisheries Management 33(5): 887-893.
Ebert, D.A., Compagno, L.J.V. and Cowley, P.D. 2008. Aspects of the reproductive biology of skates (Chondrichthyes: Rajiformes: Rajoidei) from southern Africa. ICES Journal of Marine Science 65: 81-102.
Farrugia, T.J., Goldman, K.J., Tribuzio, C. and Seitz, A.C. 2016. First use of satellite tags to examine movement and habitat use of big skates Beringraja binoculata in the Gulf of Alaska. Marine Ecology Progress Series: Abstract doi: 10.3354/meps11842 (in press).
Gburski, C.M., Gaichas, S.K., and Kimura, D.K. 2007. Age and growth of big skate (Raja binoculata) and longnose skate (R. rhina) in the Gulf of Alaska. Environmental Biology of Fishes 80: 337-349.
Hitz, C.R. 1964. Observations on egg cases of the big skate (Raja binoculata Girard) found in Oregon coastal waters. Journal of the Fisheries Research Board of Canada 21: 851–854.
Hoff, G.R. 2007. Reproduction of the Alaska skate (Bathyraja parmifera) with regard to nursery sites, embryo development and predation. University of Washington.
Ishihara, H., Treloar, M., Bor, P.H.F., Senou, H. and Jeong, C.H. 2012. The comparative morphology of skate egg capsules (Chondrichthyes: Elasmobranchii: Rajiformes). Bulletin of the Kanagawa Prefectural Museum (Natural Science) 41: 9-25.
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-2. Available at: www.iucnredlist.org. (Accessed: 04 September 2016).
King, J.R. and MacFarlane, G.A. 2010. Movement patterns and growth estimates of big skate (Raja binoculata) based on tag-recapture data. Fisheries Research 101(1): 50-59.
King, J.R., Surry, A.M., Garcia, S. and Starr, P.J. 2015. Big Skate (Raja binoculata) and Longnose Skate (R. rhina) stock assessments for British Columbia. Department of Fisheries and Oceans Canada Can. Sci. Advis. Sec. Res. Doc. 2015/070. pp. 329.
Love, M., Mecklenburg, C.W., Mecklenburg, T.A. and Thorsteinson, L.K. 2005. Resource Inventory of Marine and Estuarine Fishes of the West Coast and Alaska: A Checklist of North Pacific and Arctic Ocean Species from Baja California to the Alaska–Yukon Border. U. S. Department of the Interior, U.S. Geological Survey, Biological Resources Division, OCS Study MMS 2005-030 and USGS/NBII 2005-001, Seattle, Washington.
Martin, L.K. and Zorzi, G.D. 1993. Status and review of the California skate fishery. Conservation Biology of Elasmobranchs. NOAA Technical Report NMFS.
McFarlane, G.A., and King, J.R. 2006. Age and growth of big skate (Raja binoculata) and longnose skate (Raja rhina) in British Columbia waters. Fisheries Research 78: 169-178.
Ormseth, O. 2011. Gulf of Alaska skates. Stock assessment and fishery evaluation report for the groundfish resources of the Gulf of Alaska region. North Pacific groundfish stock assessment and fishery evaluation reports for 2011.
Ormseth, O.A. 2014a. Assessment of the skate stock complex in the Bering Sea and Aleutian Islands. Stock Assessment and Fishery Evaluation Report for the Groundfish Resources of the Bering Sea and Aleutian Islands Region. National Marine Fisheries Service Alaska Fisheries Science Center, Seattle, Washington. 1693-1782.
Ormseth, O.A. 2014b. Assessment of the skate stock complex in the Gulf of Alaska. Stock Assessment and Fishery Evaluation Report for the Groundfish Resources of the Gulf of Alaska Region. National Marine Fisheries Service Alaska Fisheries Science Center, Seattle, Washington. 855-920.
PFMC (Pacific Fisheries Management Council). 2014. Pacific Coast Groundfish Fishery Management Plan. Pacific Fishery Management Council, Portland, Oregon.
Roedel, P.M. and Ripley. W.E. 1950. California sharks and rays. California Department of Fish Game Fish Bulletin 75.
Stein, D.L., Tissot, B.N., Hixon, M.A. and Barss, W. 1992. Fish habitat associations on a deep reef at the edge of the Oregon continental shelf. Fishery Bulletin 90(3): 540–551.
Walford, L.A. 1935. The sharks and rays of California. California Department of Fish and Game Fish Bulletin 45: 1–66.
Zeiner, S.J. and Wolf, P. 1993. Growth characteristics and estimates of age at maturity of two species of skates (Raja binoculata and Raja rhina) from Monterey Bay, California. NOAA Technical Report NMFS.
|Citation:||Farrugia, T.J., Goldman, K.J., King, J.R. & Ormseth, O.A. 2016. Beringraja binoculata. The IUCN Red List of Threatened Species 2016: e.T44183A80679344.Downloaded on 22 July 2018.|
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Is life inevitable,due to the laws of nature?
"The formula, based on established physics, indicates that when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life."
"Self-replication (or reproduction, in biological terms), the process that drives the evolution of life on Earth, is one such mechanism by which a system might dissipate an increasing amount of energy over time. As England put it, “A great way of dissipating more is to make more copies of yourself.” In a September paper in the Journal of Chemical Physics, he reported the theoretical minimum amount of dissipation that can occur during the self-replication of RNA molecules and bacterial cells, and showed that it is very close to the actual amounts these systems dissipate when replicating. He also showed that RNA, the nucleic acid that many scientists believe served as the precursor to DNA-based life, is a particularly cheap building material. Once RNA arose, he argues, its “Darwinian takeover” was perhaps not surprising."
http://www.scientificamerican.com/artic … y-of-life/
Yes, life began in the deep blue sea
And eventually ended up being me.
But where did the microbes come from?
Some say meteorites!
But none of this is proved at all.
The scientists aren't sure.
Meteorites, Mars, comets, primordial soup...we'll never know with absolute surety. Not unless we learn to time travel and watch it happen.
Unless it's an ongoing thing. Then we'd be able to replicate it in the lab.
No - if it is possible that it was the soup, we can show that but we still can't show it was the soup. Same thing for a meteorite or a comet. Replicating what might have happened won't prove it did happen; just that it might have.
I agree with that, however what I'm saying is that it might be an ongoing process,and not just something that happened once, billions of years ago.
It could be happening today, how would we know it? If we can figure that out (the rules of life), we could create it in the lab easily.
I have doubts there was a one-time-only primordial soup scenario. I think life is just an inevitable part of the structure of the universe.
And I tend to agree. Given the conditions at the time, the life we know was probably inevitable and probably developed multiple times. I think we'd have a really hard time proving that no other type of life (carbon/water/DNA based) is possible - there may have been 100 different forms of life produced on this old ball before one of them took precedence and eliminated the others. And I really have little doubt that it is going on elsewhere in the universe even as you read this.
I think life is probably abundant in the universe, but it is probably in the form of simpler forms like bacteria. We are probably lucky on this planet to evolve such a variety of increasingly complex forms. Earth is likely a "garden of eden" type planet, with a lot of lucky breaks. Like having a great climate for producing and maintaining complex life. And having a large planet like Jupiter out there to vacuum up the majority of destructive comets etc.
I bet there is life out there, and we will find it on Titan etc.
I disagree about the earth being "perfect" for life (although Jupiter and the moon are good points). Rather, I think life will evolve, and to something higher than bacteria, most places it is even half way possible. Titan, Europa, Enceladus and few other spots in the solar system. I even think we'll probably find that Mars had life in the past and may still harbor simple life.
Honestly we have no way of knowing. We know how it happened here; we know how it did not happen on the other places we have data on. But we have no idea whether or how it may have happened elsewhere which is needed to extrapolate any rules about what the necessary and sufficient causes of life arising on a planet are.
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In collaboration with colleagues from Berlin and Madrid, researchers at the Department of Physics at the University of Basel have pulled up isolated molecular chains from a gold surface, using the tip of an atomic force microscope (AFM). The observed signal provides insight into the detachment force and binding energy of molecules. The results have been published in the renowned scientific journal PNAS.
Atomic force microscopy is a method normally used for imaging matter with very high resolution. The sharp tip of the microscope is used to scan the surface line by line. The resolution is so high, that single atoms can be seen.
“This method is roughly equivalent to using the tip of the Matterhorn to scan the surface of a tennis ball”, says Prof. Ernst Meyer of the Department for Physics at the University of Basel. Due to an improved method, the scientists are now able to investigate the mechanical behavior of a single polymer being pulled off a surface.
Using the tip of the AFM, the researchers were able to pull single chains of molecules (polymers) off a gold surface. “The molecule-surface interaction during pulling is so weak that each chain link (molecular unit) detaches successively.
Thus, the whole chain can be pulled off almost vertically to the surface”, explains Meyer. By analyzing the observed oscillations, the researchers are able to make quantitative statements on the binding energy of each molecular unit.
Motion without friction
Furthermore, the experiments showed that the polymers could be pulled off with almost no lateral forces. This remarkable behavior of nearly frictionless motion was predicted by a theoretical model and has now been verified for molecules on a gold surface.
Previously, the mechanical behavior of single polymer during pulling from a surface had never been investigated with atomic-scale resolution. The findings and calculations of the research team now provide detailed insight into this process for the first time.
Such investigations are not only of interest for the field of physics, but also for biology and chemistry, since the method of pulling polymers from surfaces can also be applied to biological molecules. So far, valuable insights have been obtianed into the folding and unfolding of DNA and proteins. Chemical reactions of small biopolymer sub units or complex polymer chains under the influence of traction forces and catalytic nanoparticles could be investigated with this new method.
Shigeki Kawai, Matthias Koch, Enrico Gnecco, Ali Sadeghi, Rémy Pawlak, Thilo Glatzel, Jutta Schwarz, Stefan Goedecker, Stefan Hecht, Alexis Baratoff, Leonhard Grill and Ernst Meyer
Quantifying the atomic-level mechanics of single long physisorbed molecular chains
PNAS Early Edition | doi: 10.1073/pnas.1319938111
Prof. Ernst Meyer, University of Basel, Department of Physics, phone: +41 61 267 37 24, email: firstname.lastname@example.org
Olivia Poisson | Universität Basel
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....
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You might think you have nothing in common with mustard except hotdogs. Yet based on research in a plant from the mustard family, Salk scientists have discovered a possible explanation for how organisms, including humans, directly regulate chemical reactions that quickly adjust the growth of organs.
Upon sensing the threat of shade from a neighboring plant, Arabidopsis thaliana plants rapidly elongate different tissues by increasing the levels of growth-promoting hormones. This growth is regulated by the VAS1 enzyme. As seen in the photo on the right, plants lacking VAS1 have an exaggerated response to shade.
Credit: Courtesy of the Salk Institute for Biological Studies
These findings overturn conventional views of how different body parts coordinate their growth, shedding light on the development of more productive plants and new therapies for metabolic diseases.
Metabolism refers to all the chemical reactions in the body that drive the basic processes of life: birth, growth, reproduction, digestion, sensing and so on. These reactions are orchestrated and quickened by molecular machines called enzymes. Until now, it was believed that each metabolic function required an entirely separate enzyme pathway. Further complicating the picture, scientists focused almost exclusively on genes switching on and off as the means by which each step in the pathway was regulated, roughly analogous to waiting for a part to be ordered then manufactured before the engine can run.
In a paper in this week's Nature Chemical Biology, Salk scientists and Howard Hughes Medical Institute Investigators Joanne Chory and Joseph P. Noel and their colleagues show that metabolic steps can be much more streamlined and linked. Unexpectedly, two separate pathways originally thought to be controlled solely by gene switches can have enzyme canals between them, allowing them to quickly share abundant building blocks for two separate chemical messages known as hormones. These hormones are manufactured in one part of the body in response to changes in environment and quickly alter growth in other parts. Many times, at least two hormones are needed to quickly adjust growth of different tissues in response to a single event.
"Genes are the instruction manuals for how cells build specific enzymes in a pathway, but if you have to wait for many enzymes to be made at the appropriate time in the right place to make several essential hormones, it's too slow a response to environmental changes like light," says geneticist Chory, the Howard H. and Maryam R. Newman Chair in Plant Biology, "It makes sense biologically that there is a faster, more direct way to coordinate and make these chemical messages."
While such details may seem abstract, these basic biochemical insights are fundamental to the development of better crops and therapies for disease, including the breeding of plants more adapted to challenging environments and the discovery of new medicines, explains biochemist Noel, holder of the Arthur and Julie Woodrow Chair.
"It is essential to understand what steps bodies, plant or animal, take to construct and process chemical information in order to produce more food and treat metabolic diseases," he says.
Chory, Noel and Salk post-doctoral researchers Zuyu Zheng and Yongxia Guo, co-first authors on the paper, made their discovery by studying thale cress (Arabidopsis thaliana), a small plant with tiny white flowers that grows wild throughout much of the world. Thale cress has become a profoundly important research model to scientists studying genetics and metabolism, because it grows to maturity in only six weeks and its genes can be quickly tested for what instructions they give the plant. This allows researchers to rapidly learn what genes regulate the production of proteins and enzymes essential to metabolism. This basic information can then translate into better crop plants and disease treatments.
When the top of a plant is shaded, two different parts of the plant quickly adjust their growth rate so the plant can compete for sunlight. The stem or trunk of the plant will rapidly grow longer, often in only a few hours, in an attempt to avoid being trapped in shade. Another part, the tissue known as the "petiole," which connects a leaf to the stem, also elongates as it reaches for the sun. Together, these two organs allow the plant to more efficiently carry out photosynthesis, which turns light and carbon dioxide into life sustaining food.
The growth of the two parts is controlled by two different metabolic pathways that make two very distinct chemical hormones. Stem growth is triggered by the hormone auxin, while petiole growth is stimulated by the hormone ethylene. Our own bodies use hormones in similar growth pathways, which follow the same complicated metabolic rules.
Zheng and Guo discovered that there is an enzyme, called VAS1, that functions as a canal between the auxin and ethylene pathways. Like the Panama Canal, VAS1 isn't merely a shortcut between two pathways, but a gating mechanism that regulates these two different hormone levels simultaneously, ensuring that different parts of the plant grow in a balanced way and not wildly out of control. With VAS1 in place as a gate, there's no need to wait for genes to turn on and off to make these hormones in a coordinated manner.
These tiny plants have given us a new way of thinking about coordinating metabolism in all species, says Chory. "Evolution is conservative," she explains, "If you find a mechanism in one system, the likelihood is high that you will quickly find it throughout all of nature."
Noel agrees, adding, "We've shown that there needs to be serious re-thinking of the conventional wisdom of how metabolic process are synchronized and how this synchronization fails in disease."
Other researchers on the study were: Xinhua Dai and Yunde Zhao, of the University of California-San Diego; Ondřej Novák, of the Swedish University of Agricultural Sciences, Umeå, Sweden, and Palacky University and the Academy of Science of Czech Republic, Olomouc, Czech Republic; and Karin Ljung, of the Swedish University of Agricultural Sciences, Umeå, Sweden.
The work was supported by the Howard Hughes Medical Institute, the National Institutes of Health, the National Science Foundation, the Internal Grant Agency of Palacky University in the Czech Republic, the Grant Agency of the Academy of Sciences of the Czech Republic, the Swedish Governmental Agency for Innovation Systems and the Swedish Research Council.
Andy Hoang | EurekAlert!
Colorectal cancer risk factors decrypted
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Algae Have Land Genes
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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...
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Researchers looked at 3,500-year-long tree ring records from North East Tibet to estimate annual precipitation. They found that recent decades have likely been the wettest on record in this semi-arid region.
Photo: taken by Jialiang Gao on the Tibetan Plateau
The precipitation records have been reconstructed using sub-fossil, archaeological and living juniper tree samples from the north-eastern Tibetan Plateau. They reveal a trend towards wider growth rings, implying moister growing conditions – with the last 50 years seeing increasing amounts of rainfall.
Notable historical dry periods occurred in the 4th Century BC and in the second half of the 15th Century AD.
Dr Tim Osborn from UEA’s Climatic Research Unit said: “Our collaboration with scientists from China has been very fruitful, leading to what is currently the longest tree-ring-width record in the cold and arid north-eastern Tibetan Plateau. Not only is the record very long, it is based on samples from more than 1000 trees, some of which have an individual lifespan of more than 2000 years. These are among the longest-lived trees in the world.”
Not only are these trees long-lived, but they are useful for understanding how climate has changed. The widths of the tree rings show a close correspondence with observations from rain gauges over the last 55 years, such that tree rings in wetter years tend to be wider than tree rings in drier years.
Dr Osborn said: “The most recent few decades have, on average, the widest rings in the 3,500-year record which suggests that this may have been the wettest period, perhaps associated with global warming during the last century. Indeed, over the last two thousand years when the Northern Hemisphere is warm it appears to be wetter in the Mountains of North East Tibet. This suggests that any further large-scale warming might be associated with even greater rainfall in this region – though we note that other factors could also have contributed to the increased ring widths.”
‘A 3500-year tree-ring record of annual precipitation on the north-eastern Tibetan Plateau’ is published in Proceedings of the National Academy of Sciences.
Lisa Horton | EurekAlert!
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