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Edited By: NC Aery and Shruti Kshirsagar
300 pages, 100 black & white illustrations
This book presents current methods for determining the impact of pollutants on the biosystem and enzymes, instrumentation, and statistical methods. Encompassing the breadth and depth of the field, this book explores analytical methods for determining physical, chemical, biological, and microbiological characteristics of water, waste water, soil, plant material, and air as well as plant and animal communities.
Including sampling, instrumentation, and monitoring methods, this book facilitates analysis for a wide range of chemical pollutants. Topics include bioassays, environmental radioactivity, biomonitoring, environmental impact assessment/auditing, and indoor air and noise pollution.
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Application Progress on Goldstone Solar System Radar and Its Inspiration for Deep Space Exploration in China
Li Dewei1，2，Jiang Liming1，2，Jiang Houjun3
(1.State Key Laboratory of Geodesy and Earth’s Dynamics，Institute of Geodesy and Geophysics，Chinese Academy of Sciences，Wuhan 430077，China；2.University of Chinese Academy of Sciences，Beijing 100049，China；3.Nanjing University of Posts and Telecommunications，Nanjing 210023，China)
Abstract：Goldstone Solar System Radar(GSSR) has been played an important role in international deep space exploration and widely used in lunar terrain mapping，Mars exploration，asteroids orbit determination，deep space aircraft measurement or control，etc.We reviewed the background and summarized the present development situation of the GSSR system which is the only fully steerable imaging radar system in the world for planetary and small\|body targets.Then，we analyzed the composition of the GSSR system and its imaging principle of the near\|Earth objects in details.In addition，we emphatically introduced the new applications of GSSR in deep space exploration.GSSR has provided an inspiration for the deep space exploration in China and given a valuable reference to Lunar\|based Synthetic Aperture Radar(SAR) for Earth observation.
李德伟，江利明，蒋厚军. GSSR成像雷达应用进展及其对我国深空探测的启示[J]. 遥感技术与应用, 2018, 33(3): 377-386.
Li Dewei，Jiang Liming，Jiang Houjun. Application Progress on Goldstone Solar System Radar and Its Inspiration for Deep Space Exploration in China. Remote Sensing Technology and Application, 2018, 33(3): 377-386. | <urn:uuid:c7f6b8aa-158d-4ad1-807f-b9a7e58a2d86> | 2.515625 | 489 | Academic Writing | Science & Tech. | 37.797647 | 95,643,104 |
The Theoretical and Technical Development of Field-Ion Microscopy
A field-ion microscope is the most powerful microscopic device known today. It is the only instrument that can show directly the atomic structure of a specimen and the atomic lattice defects. But, for reasons that might lie in the difficulty of operation of the first instruments, perhaps the unorthodoxy of the principles involved, and a justified lack of commercial interest, it took a long time to be developed. When in the spring days of quantum mechanics Gamow1 (1928) explained the radioactive alpha decay as a tunneling effect, field-electron emission from metals was soon recognized by Fowler and Nordheim2 as another example of barrier penetration and simultaneously Oppenheimer3 suggested that the effect of field ionization of free atoms could occur when an electron would tunnel out in the presence of an electric field. While the first two effects commanded considerable interest, field ionization from the ground state of an atom was experimentally inaccessible because of the magnitude of the fields required. Handling large fields became a possibility with the introduction of the field-emission microscope in 1936.4 With the discovery of field desorption5 from a positive-point electrode the field range beyond 100 MV/cm, in which all effects of interest to us are taking place, was entered for the first time. The realization that the resolution limit of the field-electron microscope6 is determined by the tangential velocity of the emitted electrons and, to a lesser extent, by their de Broglie wavelength, which cannot be controlled under the prevailing conditions, led in 1951 to successful imaging of the emitter surface with positive ions rather than electrons.7 Atomic resolution was thus achieved for the first time.
KeywordsField Ionization Field Evaporation Proper Operating Condition Evacuate Glass Tube Lateral Velocity Component
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- 3.J. R. Oppenheimer, Phys. Rev. 31: 67 (1928).Google Scholar
- 8.E. W. Müller, Z. Naturforsch. 11a: 87 (1956); also J. Appl. Phys. 27: 474 (1956).Google Scholar
- 11.E. W. Müller, Advances in Electronics and Electron Physics, Vol. XIII, Academic Press (New York), 1960, pp. 83–179.Google Scholar
- 12.R. Gomer, Field Emission and Field Ionization, Harvard University Press (Cambridge, Mass.), 1961.Google Scholar
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- 14.D. G. Brandon, Surface Sci. 3: 1 (1965).Google Scholar
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- 19.E. W. Müller, Ann. d. Physik 20 : 316 (1957).Google Scholar | <urn:uuid:e901ac3c-0853-4f86-b490-1a8b1c8586db> | 3.4375 | 636 | Truncated | Science & Tech. | 58.57775 | 95,643,127 |
The same type of forces are at work bringing the building blocks of viruses together, and the inorganic supercluster structures in this research are in many ways similar to viruses.
Engineering researchers have discovered that under the right circumstances, basic atomic forces can be exploited to enable nanoparticles to assemble into superclusters that are uniform in size and share attributes with viruses. Credit: T.D.Nguyen, Glotzer Group, University of Michigan
U-M chemical engineering professors Nicholas Kotov and Sharon Glotzer led the research. The findings are newly published online in Nature Nanotechnology.
In another instance of forces behaving in unexpected ways at the nanoscale, they discovered that if you start with small nanoscale building blocks that are varied enough in size, the electrostatic repulsion force and van der Waals attraction force will balance each other and limit the growth of the clusters. This equilibrium enables the formation of clusters that are uniform in size.
"The breakthrough here is that we've discovered a generic mechanism that causes these nanoparticles to assemble into near perfect structures," Glotzer said. "The physics that we see is not special to this system, and could be exploited with other materials. Now that we know how it works, we can design new building blocks that will assemble the same way."
The inorganic superclusters—technically called "supraparticles"—that the researchers created out of red, powdery cadmium selenide are not artificial viruses. But they do share many attributes with the simplest forms of life, including size, shape, core-shell structure and the abilities to both assemble and dissemble, Kotov said.
"Having these functionalities in totally inorganic system is quite remarkable," Kotov said. "There is the potential to combine them with the beneficial properties of inorganic materials such as environmental resilience, light adsorption and electrical conductivity."
Zhiyong Tang, a collaborating professor at the National Center of Nanoscience and Technology in China, said, "It is also very impressive that such supraparticles can be further used as the building blocks to fabricate three-dimensional ordered assemblies. This secondary self-assembly behavior provides a feasible way to obtain large-scale nanostructures that are important for practical application."
Kotov is currently working on "breeding" these supraparticles to produce synthetic fuels from carbon dioxide. The work also has applications in drug delivery and solar cell research and it could dramatically reduce the cost of manufacturing large quantities of supraparticles.
"By replicating the self-assembly processes that allow living organisms to grow and heal, we can simplify the production of many useful nanostructured systems from semiconductors and metals so much so that they can be made in any high school laboratory," Kotov said.
This research is funded by the Department of Defense, the National Science Foundation and the U.S. Army Research Office.
Nicole Casal Moore | EurekAlert!
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Buffer Object Streaming
- Buffer Objects
- Vertex Array Objects
- Asynchronous query objects
- Framebuffer Objects
- Unconventional objects:
Buffer Object Streaming is the process of updating buffer objects frequently with new data while using those buffers. Streaming works like this. You make modifications to a buffer object, then you perform an OpenGL operation that reads from the buffer. Then, after having called that OpenGL operation, you modify the buffer object with new data. Following this, you perform another OpenGL operation to read from the buffer.
Streaming is a modify/use cycle. There may be a swap buffers (or equivalent frame changing process) between one modify/use cycle and another, but not necessarily.
OpenGL puts in place all the guarantees to make this process work, but making it work fast is the real problem. The biggest danger in streaming, the one that causes the most problems, is implicit synchronization.
The OpenGL specification permits an implementation to delay the execution of drawing commands. This allows you to draw a lot of stuff, and then let OpenGL handle things on its own time. Because of this, it is entirely possible that, well after you call whatever operation that uses the buffer object, you might start trying to upload new data to that buffer. If this happens, the OpenGL specification requires that the thread halt until all drawing commands that could be affected by your update of the buffer object complete.
This implicit synchronization is the primary enemy when streaming vertex data.
There are a number of strategies to solve this problem. Some implementations work better with certain ones than others. Each one has its benefits and drawbacks.
The very first thing you should do is make sure that STREAM is in your buffer's hint.
Explicit multiple buffering
This solution is fairly simple. You simply create two or more buffer objects of the same length. While you are using one buffer object, you can be modifying another. Depending on how much parallelism your implementation can provide, you may need more than two buffers to make this work.
The principle drawback to this solution is that it requires using a number of different buffer objects (separate buffer handles). So you'll need to change which buffers you're using for your GPU operations every frame.
This solution is to reallocate the buffer object before you start modifying it. This is termed buffer "orphaning". There are two ways to do it.
The first way is to call glBufferData with a NULL pointer, and the exact same size and usage hints it had before. This allows the implementation to simply reallocate storage for that buffer object under-the-hood. Since allocating storage is (likely) faster than the implicit synchronization, you gain significant performance advantages over synchronization. And since you passed NULL, if there wasn't a need for synchronization to begin with, this can be reduced to a no-op. The old storage will still be used by the OpenGL commands that have been sent previously. If you continue to use the same size over-and-over, it is likely that the GL driver will not be doing any allocation at all, but will just be pulling an old free block off the unused buffer queue and use it (though of course this isn't guaranteed), so it is likely to be very efficient.
All of these give the GL implementation the freedom to orphan the previous storage and allocate a new one. Which is why this is called "orphaning".
Whenever you see either of these, think of it as a directive to OpenGL to 1) detach the old block of storage and 2) give you a new block of storage to work with, all behind the same buffer handle. The old block of storage will be put on a free list by OpenGL and reused once there can be no draw commands in the queue which might be referring to it (e.g. once all queued GL commands have finished executing).
Obviously, these methods detach the buffer storage from the client-accessible workspace, so they are only practical if there is no further need to read or update this specific block of storage from the GL client side. Unless you plan to use buffer updates in combination with this technique, then it is best if updates are done on a whole buffer rather than parts of a buffer, and if you overwrite all of the data in that buffer each time.
One issue with this method is that it is implementation dependent. Just because an implementation has the freedom to do something does not mean that it will.
Buffer update is form of streaming that you need to be very careful with. It is often used in combination with buffer re-specification to increase submission performance.
To implement buffer update, we call glMapBufferRange with the GL_MAP_UNSYNCHRONIZED_BIT. This tells OpenGL not to do any implicit synchronization at all. When you see this, think "OpenGL, please give me a buffer 'fast'. It's fine if you give me the same one for this buffer object that you did last time. I promise not to modify any portion of this buffer that might be in use by a GL command I've already submitted. Just trust me."
Though there is no synchronization, this does not mean that synchronization is unimportant. Indeed, you will get undefined results if you are modifying parts of the buffer that already-queued GL commands (such as draw commands) will read from on the GPU. Don't do that.
The basic use case for using buffer updates is that you can progressively fill up a buffer object with Map UNSYNCHRONIZED, write, unmap, issue GL command using that buffer subregion, rinse/repeat. And so long as your writes never overlap, then you're safe and you don't need to think about "messing up the GPU's data" until you fill up that buffer. Once you fill it up, you can do one of two things to continue to avoid stomping on the GPU's buffer data: 1) orphan, or 2) synchronize. Orphan being the preferred method as avoiding synchronization usually yields higher performance (as synchronization often involves waiting).
To orphan, just use the buffer re-specification technique (glBufferData(NULL), glMapBufferRangeGL_MAP_INVALIDATE_BUFFER_BIT, or glInvalidateBufferData). You then get a fresh block of storage underneath the buffer handle to scribble on that no other GL commands can be referring to, so no synchronize is needed.
Alternatively, to synchronize, use a sync object. If you put a fence after all of the commands that read from a buffer, you can check whether this fence has completed before mapping the buffer. If it has not, then you can wait to update the buffer, performing some other important task in the meantime. You can also use the fence to force synchronization if you have no other tasks to perform. Once the fence has completed, you can map the buffer freely, using the GL_MAP_UNSYNCHRONIZED_BIT just in case the implementation isn't aware that the buffer can be updated.
For more details on buffer streaming in general, see this thread. Pay particular attention to the posts by Rob Barris.
Persistent mapped streaming
Given the availability of OpenGL 4.4 or ARB_buffer_storage, the use of persistent mapping of buffers becomes a possibility.
The idea here is to allocate an immutable buffer 2-3x the size you need, and while you're executing operations from one region of the buffer while you are writing to a different region. The difference between the prior mapping scheme is that you are not frequently mapping and unmapping the buffer. You map it persistently when you create the buffer, and keep it mapped until it's time to delete the buffer.
The general algorithm is as follows. The buffer is logically divided into 3 sections: the section you're writing to, and two sections that could currently be in use.
The first step is to write to section 1 of the buffer. Once you have finished writing, you must make this range of data visible to OpenGL by flushing it (if you aren't mapping coherently). Then, you do whatever you need to in order to ensure that this data is visible to OpenGL. Once the data is visible, you issue some number of Rendering Commands that read from that section of the buffer. After issuing all of the commands that read from the buffer, you create a fence sync object.
Next frame, you start writing to buffer section 2. You do all of the above, and create a new fence sync object. Keep each buffer section's sync objects separate.
You do the same with buffer section 3 on the next frame.
On the fourth frame, you want to start using section 1 again. However, you need to check section 1's sync object to see if it has completed before you can start. You can only start writing to a section if that section's sync object has completed.
Writing to a persistently mapped buffer does not guarantee automatically that OpenGL will see the written data. To ensure visibility, you must do one of three things.
- Map the buffer coherently with GL_COHERENT_BIT. This also requires allocating the buffer with GL_COHERENT_BIT. Coherently mapped buffers always ensure visibility to subsequent operations (this does not mean you get to write to something currently being read, however. You still need synchronization). While this might sound slow, there is some evidence that the performance cost is negligible, at least on some hardware.
- Issue the memory barrier glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT). All writes to a persistently mapped buffer made before calling this function will be visible to any OpenGL operation issued after the call to this function.
- Map the buffer with GL_MAP_FLUSH_EXPLICIT_BIT and call glFlushMappedBufferRange on the written section of the buffer.
According to Rob Barris, MAP_INVALIDATE_RANGE_BIT in combination with the WRITE bit (but not the READ bit) basically says to the driver that it doesn't need to contain any valid buffer data, and that you promise to write the entire range you map. This lets the driver give you a pointer to scratch memory that hasn't been initialized. For instance, driver allocated write-through uncached memory. See this post for more details. | <urn:uuid:6210e360-a085-4507-924f-f440a8073cbf> | 3.328125 | 2,142 | Documentation | Software Dev. | 48.310707 | 95,643,178 |
Learn Fortran Programming is a completely free application.
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There are shades of Hal Clement's Science Fiction (SciFi) novel "Mission of Gravity", where aliens are employed by Earth's scientists to investigate a fast spinning super Jupiter type planet in sailing ships. However, this article about a nautical craft for Saturn's moon Titan, is a real proposed scientific project, although no aliens are involved as crew members!
The first interplanetary nautical craft may be a boat to explore the methane seas of Titan. A proposed mission to Titan would explore some of its largest seas, including Ligeia Mare (pictured) or the Kraken Mare, both of which are in the northern hemisphere of the foggy moon of Saturn. The concept has been studied for over two years by scientific team led by Ellen Stofan of Proxemy Research, Inc. in Washington DC, and has recently been submitted to NASA.
Rorting In The Auckland Property Market !
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Flow cell for real time observation of single particle adhesion and detachment
A flow cell was built for observing particle removal from test surfaces in real time. The removal force is the hydrodynamic force exerted on the particle by liquid flowing parallel to the test surface. Particle removal was detected visually either through a microscope or on a video monitor. All experimental results reported here are based on the removal of deposited 10 ?m polystyrene (PSL) spheres from one of 3 surfaces: polished aluminum; polished bare silicon wafers (native oxide only); or thertnally oxidized silicon wafers. One of 3 cleaning liquids was used: dilute SC-1, dilute SC-2, or de-ionized water containing 0.01% Micro®. The hydrodynamic removal force was controlled primarily by controlling the liquid flow rate. In all experiments, as the flow rate increased, single polystyrene latex (PSL) spheres detached first, then doublets, then triplets and finally larger agglomerates; that is, the adhesion force increased more rapidly with agglomeration than the hydrodynamic removal force. By applying theoretical calculations from the literature, this flow cell can be used to estimate the hydrodynamic forces necessary for removal of particles from surfaces.
Yamamoto, T., Periasamy, R., Donovan, R., & Ensor, D. (1995). Flow cell for real time observation of single particle adhesion and detachment. Journal of Adhesion Science and Technology, 8(5), 543-552. DOI: 10.1163/156856194X00221 | <urn:uuid:c8688211-7f27-4b43-8944-327234ed4a86> | 2.78125 | 333 | Academic Writing | Science & Tech. | 33.312544 | 95,643,240 |
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Moreover, it shall focus on a rhetorical analysis of Kepler, Hey and Krupp.
There are different modes of expressing information on issues ascribed to astronomy and how this knowledge has been changing from time to time. Different writers and researchers have applied varying modes of communication or language structure to express this information in a manner that creates a great sense of impact. Taking the case of Edward Rosen’s writing that focus on the Three Treaties of Copernicus, Rosen begins by describing different ways through, which different generations made efforts to improve their understanding of the nature of the planetary bodies for instance: He notes that the early ancestors focused on the use of regulatory principles to facilitate their understanding of the celestial bodies, but their efforts were unsuccessful.
Rosen goes further and describe the efforts of Callipus and Euxodus that were directed to explain issues ascribed to the celestial spheres, through the use of centric spheres. However, he alludes that this ideology was also unsuccessful. In order to give a real scenario of how the efforts to facilitate the understanding of planetary bodies have changed, he goes further and describes the use of Planetory Theories that were applied Ptolemy, that basically involved the use of data in a numerical dimension. Although, these efforts as depicted by Rosen in his writing, were unsuccessful and thus created the need for more effective methodologies of understanding the celestial bodies. Taking an analysis of Rosen’s work on the Three Treaties of Copernicus, it is evident that he applies the use of examples indicating different ways through, which generations made efforts to understand the natural structure of celestial bodies.
Another source of information that has been used to explicit changes in relation to the
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“However, considering the fact that the solar system began as a cloud of gas and dust that was near absolute zero we might wonder where the earths internal heat came from to drive the plate tectonics.” (The Heat History of Earth) It is a confusing question for the
In ancient civilizations constellations were used for astrology or myths. Astrology is where stars and planets are tracked in order to predict an individual or society’s future. Constellations like Orion, Mars, and Jupiter
From the study of astronomy emerges the study of black holes, a major frontier about which much has been theorized but little really known. Black holes can be defined as “a concentration of matter so dense that not even
That is just one math example but there are several others which demonstrate this logical point easily.
Some distances are measured in light-years and some are measured in astronomical units. This is because light-years are used to demonstrate how
ve argument, the theory has changed adversely from molecular to atomic nature, from low to high acceptance, from knowledge to better information on the nature of the atoms. Evolution theory has been known to address the changes in the world systems over time.
Astronomy is classified as a natural science that included the study of celestial objects such as stars, moon, planets, galaxies and nebulae. In addition, it also deals with the physics, chemistry, and the objects evolution, and phenomena that originate outside the earth’s atmosphere.
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Artificially created island in the shape of a circle with a radius of 50 m is overgrown with grass. The only exception is a landing area for helicopters in the shape of a rectangle measuring 15 m and 8 m. What is the probability that the flying seagull (without the use of the senses, eyes, ......) make land to landing area?
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For the past three decades, deep crustal studies of the British Isles have been restricted to the interpretation of 2-D seismic reflection and refraction profiles, mostly acquired offshore. During this period, the British Geological Survey (BGS) seismic monitoring network has developed to an unrivalled density for a region of low intraplate seismicity. In an average year, the modern network records approximately 40 earthquakes in the crust beneath the British Isles with local magnitudes > 2. Statistical tests show the modern and historical pattern is not random. Understanding of the tectonic processes behind the pattern are hindered by the sparseness of onshore deep crustal studies where the majority of earthquakes are concentrated.\ud For the first time local earthquake tomography, a method more commonly applied to tectonically active regions, is used to produce high resolution 3-D images of seismic P-wave velocity (Vp) and the P- to S-wave velocity ratio (Vp/Vs) in the crust beneath England, Wales and the Irish Sea. To account for low seismicity, over 1,000 earthquakes are utilised from the past 25 years of monitoring. The existing BGS digital catalogue is enhanced by a two-fold increase in seismic arrival time picks, significantly reducing earthquake location errors in the input dataset.\ud The tomographic models establish a strong and previously undemonstrated link between Palaeocene magmatism and more widespread earlier phases of Caledonian magmatism. A regional Vp anomaly (> 7.2 km/s) in the lower crust centred on the East Irish Sea Basin is inferred as Palaeocene magmatic underplate with seismicity concentrated around its eastern and southern margins. In the mid- and lower-crust earthquake clusters are evident around the edges of local Vp/Vs anomalies (> 1.80), most significantly beneath the Ordovician volcanic centre in Snowdonia. The models are supplemented by the inversion of 185 independently determined focal mechanisms to consider the influence of local variations in far-field intraplate stresses alongside lithostatic stress from overburden pressure
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why does carbon dioxide put out a flame
Make sure to This subreddit is for asking for objective explanations. It is not a repository for any question you may have. E is for Explain - merely answering a question is not enough. LI5 means friendly, simplified and layman-accessible explanations - not responses aimed at literal five-year-olds. Perform a keyword search, you may find good explanations in past threads. You should also consider looking for your question in the FAQ. Don t post to argue a point of view.
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Put out that fire! In this exciting experiment, you will be able to use common household ingredients to setup a fun, educational experience. Witness a chemical reaction that occurs when heat, oxygen and fuel are present. (A word of caution: adult supervision is required for this experiment. ) Hereвs what you need: Do This Light the candles. Place baking soda in the liquid measuring cup. Quickly add the vinegar and stir to combine.
Place a hand on the top of the liquid measuring cup to keep CO2 gas from escaping. Once the reaction has stopped, carefully pour the invisible CO2 collected in the measuring cup over the flames to extinguish them. BE CAREFUL NOT TO POUR OUT THE LIQUID IN THE BOTTOM OF THE CUP. Why did that happen? Combustion is a chemical reaction that occurs when heat, oxygen and a fuel are present. Remove any one of the three components and combustion canвt occur.
Combine vinegar and baking soda to create a chemical reaction. Carbon dioxide (CO2) gas is formed during this chemical reaction. We can see the evidence of the CO2 in the bubbles. CO2 is a very heavy gas which accumulates in the measuring cup. Gases behave in much the same way as liquids do. Pouring the heavy CO2 gas over the flame pushes away the oxygen from around the candle causing the fire to go out due to lack of oxygen.
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Man-Made Earthquakes Are on the Rise, But They Don’t Have to Be
There are alternatives to the wastewater injection that causes earthquakes and contaminates groundwater.
When the U.S. Geological Survey released its new one-year prediction of earthquake risk on Tuesday, it said some parts of Texas and Oklahoma now face the same dangers as quake-prone areas of California—and that the rise was caused by underground disposal of wastewater produced during extraction of oil and natural gas.
Wastewater is a two-pronged problem. The increased seismic risk in areas where earthquakes are normally rare is putting some seven million people at risk, according to the USGS. Such tremors are usually small, but man-made quakes have been recorded at up to magnitude 5.6.
Then there is the water itself. Extracting oil or gas through a technique known as hydraulic fracturing, or fracking, involves pumping large quantities of water underground at high pressure to fracture rock. When the water flows back out, it is laden with chemicals used in the process, plus salts and heavy metals flushed out from the rocks. (In addition to fracking, conventional oil drilling also brings up dirty water.) Most of this water is later pumped underground.
But it doesn’t need to be. Emerging treatment alternatives, including membrane desalination and ozone treatment, could render the water usable again. In addition, researchers are honing a large-scale distillation process that uses relatively little energy.
These processes are more expensive than shipping wastewater to a disposal well and injecting it, but the costs are not so high when the detrimental effects of pollution or earthquakes—and of diverting clean water in the first place—are considered.
In the meantime, the risks keep growing. In the Dallas-Fort Worth area in particular, the USGS says, the chances for man-made quakes have dramatically increased since 2014, and a significant earthquake there could cause up to $9.5 billion in damages.
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The ruby_sscanf gem monkey patches the String class to support the sscanf instance method. This method is modeled after the POSIX "C" standard sscanf but with alterations and omissions to suit the Ruby programming language.
It is noteworthy that this gem never was intended to be 100% compatible with the built in scanf library. Some differences are:
- It deals only with strings and not IO objects.
- It adds formats for rational, complex, and quoted string data.
- It adds formats with embedded regular expression specifications.
- It adopts a more uniform approach to eating (or not eating) superfluous spaces.
- Unsigned integer data are not allowed to be negative.
Add this line to your application's Gemfile:
And then execute:
Or install it yourself as:
$ gem install ruby_sscanf
The ruby_sscanf gem itself is found at: ( https://rubygems.org/gems/ruby_sscanf )
The basic usage for sscanf is:
"<input string>".sscanf("<format string>")
Where the input string is a collection of formatted information and the format string is a description of that format. The output of the sscanf method is an array of data extracted from the input string.
The format string consists of literal string components and format specifiers. During execution of the sscanf method, each element in the format string is used to find the corresponding data in the input string, optionally placing the extracted data in the aforementioned output array. If a format element cannot be matched to input data, processing stops at that point. Otherwise processing continues until all the format elements are done.
Literal string components match themselves in the input string. If the literal has a trailing space, then this matches zero or more spaces. The backslash character is used as a quoting character. Thus \\ is processed as a single \. The special sequence '%%' matches one '%' in the input string. This is equivalent to the sequence \%.
The layouts of a format specifier are:
%[skip_flag][width]format %[skip_flag][[min_width,]max_width]set %[skip_flag]regex[options]
- The % sign is the lead-in character.
- The optional skip flag, the *, causes any data extracted to be ignored.
- The width field is an integer that determines the amount of text to be parsed. Note that a .precision field may be specified, but it is ignored.
- The format field determines the type of data being parsed.
- The min_width is the minimum allowed run of characters in the set.
- The max_width is the maximum allowed run of characters in the set.
- The set field is a regular expression style [...] set.
- The regex field is a full blown regular expression followed by options.
The supported format field values are:
- a,e,f,g,A,E,F,G - Scan for an (optionally signed) floating point or scientific notation number.
- b - Scan for an (optionally signed) binary number with an optional leading '0b' or '0B'.
- c - Grab the next character. If a positive width is specified, grab width characters. For a negative width, grab characters to the position from the end of the input. For example a width of -1 will grab all of the remaining input data.
- d - Scan for an (optionally signed) decimal number.
- i - Scan for an (optionally signed) integer. If the number begins with '0x' or '0X', process hexadecimal; with '0b' or '0B', process binary, if '0', '0o', or '0O', process octal, else process decimal.
- j - Scan for an (optionally signed) complex number in the form [+-]?float[+-]float[ij]
- o - Scan for an (optionally signed) octal number with an optional leading '0', '0o' or '0O'.
- q - Scan for a quoted string. That is a string enclosed by either '...' or "...".
- r - Scan for an (optionally signed) rational number in the form [+-]?decimal/decimal[r]?
- s - Scan for a space terminated string.
- u - Scan for a decimal number.
- x,X - Scan for an (optionally signed) hexadecimal number with an optional leading '0x' or '0X'.
- [chars] - Scan for a contiguous string of characters in the set [chars].
- [^chars] - Scan for a contiguous string of characters not in the set [^chars]
- /regex/ - Scan for a string matching the regular expression. This may be followed by one or more optional flags. Supported flags are i, m, and x. Limitation: zero width (positive or negative) look behind assertions (?<= ) and (?<! ) are not supported at this time.
Here are a few exmaples of the sscanf method in action.
"12 34 -56".sscanf "%d %2d %4d" returns [12, 34, -56] "255 0b11111111 0377 0xFF 0 ".sscanf "%i %i %i %i %i" returns [255, 255, 255, 255, 0] "7 10 377".sscanf "%o %o %o" returns [7, 8, 255] "10 10011 11110000".sscanf "%b %b %b" returns [2, 19, 240] "0 F FF FFF FFFF".sscanf "%x %x %x %x %x" returns [0, 15, 255, 4095, 65535] "Hello Silly World".sscanf "%s %*s %s" returns ["Hello", "World"] "Hello Silly World".sscanf "%5c %*5c %5c" returns ["Hello", "World"] "42 The secret is X".sscanf "%i %-1c" returns [42, "The secret is X"] "42 The secret is X".sscanf "%i %-2c%c" returns [42, "The secret is ", "X"] "42 The secret is X".sscanf "%i %*-2c%c" returns [42, "X"] "9.99 1.234e56 -1e100".sscanf "%f %f %f" returns [9.99, 1.234e56, -1e100] "85% 75%".sscanf "%f%% %f%%" returns [85, 75] "12 34 -56".sscanf "%u %u %u" returns [12, 34] "1/2 3/4r -5/6".sscanf "%r %r %r" returns ['1/2'.to_r, '3/4'.to_r, '-5/6'.to_r] "1+2i 3+4j -5e10-6.2i".sscanf "%j %j %j" returns [Complex('1+2i'), Complex('3+4j'), Complex('-5e10-6.2i')] "'quote' 'silly' \"un quote\" 'a \\'' ".sscanf "%q %*q %q %q" returns ["quote", "un quote", "a '"] "a b c".sscanf "%[a] %[b] %[c]" returns ["a", "b", "c"] "a abbccc acbcad".sscanf "%/A/i %/a+b+c+/ %/([ab][cd])+/" returns ["a", "abbccc", "acbcad"] " 1234i ".sscanf(" %/\\d+/\\i") returns ["1234"]
Getting unparsed text
When a string is parsed, there may be some text at the end of the string that is not parsed. It is possible to retrieve this text using the following:
A test bed for experimenting with the ruby_sscanf gem is available as a rake task:
$ rake console
I ran a test just to make sure that ruby_sscanf was not terribly under-performant when compared to the ruby standard library version. I was pleased to see that in fact ruby_sscanf was faster. Here are the results:
Warming up -------------------------------------- Scan strings with ruby_sscanf 1.734k i/100ms Scan strings with scanf 309.000 i/100ms Calculating ------------------------------------- Scan strings with ruby_sscanf 17.926k (± 0.6%) i/s - 90.168k Scan strings with scanf 3.123k (± 0.6%) i/s - 15.759k Comparison: Scan strings with ruby_sscanf: 17925.7 i/s Scan strings with scanf: 3123.0 i/s - 5.74x slower
This benchmark test was run under:
- ruby 2.1.6p336 (2015-04-13 revision 50298) [i386-mingw32]
- format_engine version = 0.7.2
- Fork it ( https://github.com/PeterCamilleri/ruby_sscanf/fork )
- Create your feature branch (
git checkout -b my-new-feature)
- Commit your changes (
git commit -am 'Add some feature')
- Push to the branch (
git push origin my-new-feature)
- Create a new Pull Request
Go to the GitHub repository and raise an issue calling attention to some aspect that could use some TLC or a suggestion or an idea. | <urn:uuid:b98e3d8a-27e0-47c5-8e1e-ad2d18c52c63> | 3.1875 | 2,151 | Documentation | Software Dev. | 82.453887 | 95,643,318 |
The following section uses file to illustrate what is an iterator.
open file objects have a method called readline.
It reads one line of text from a file at a time-each time we call the readline method, we advance to the next line.
At the end of the file, an empty string is returned, which we can detect to break out of the loop:
f = open('main.py') # Read a four-line script file in this directory print( f.readline() ) # readline loads one line on each call # from w ww.ja v a2 s.c o m print( f.readline() ) print( f.readline() ) print( f.readline() ) # Last lines may have a \n or not print( f.readline() ) # Returns empty string at end-of-file
files also have a method named __next__ in 3.X (next in 2.X) that has the same effect.
It returns the next line from a file each time it is called.
__next__ raises a built-in StopIteration exception at end-of-file instead of returning an empty string:
f = open('main.py') print( f.__next__() ) print( f.__next__() ) print( f.__next__() ) print( f.__next__() ) print( f.__next__() )
This interface is most of what we call the iteration protocol in Python.
Any object with a __next__ method to advance to a next result, which raises StopIteration at the end of the series of results, is considered an iterator in Python.
Any such object may be stepped through with a for loop or other iteration tool.
All iteration tools work internally by calling __next__ on each iteration and catching the StopIteration exception to determine when to exit. | <urn:uuid:1bd7119c-c490-4b0a-b427-d6ef0a3bc1b9> | 4.4375 | 400 | Documentation | Software Dev. | 74.083323 | 95,643,326 |
A powerful new tool that can help advance the genetic engineering of “fuel” crops for clean, green and renewable bioenergy, has been developed by researchers with the U.S. Department of Energy (DOE)’s Joint BioEnergy Institute (JBEI), a multi-institutional partnership led by Lawrence Berkeley National Laboratory (Berkeley Lab). The JBEI researchers have developed an assay that enables scientists to identify and characterize the function of nucleotide sugar transporters, critical components in the biosynthesis of plant cell walls.
“Our unique assay enabled us to analyze nucleotide sugar transporter activities in Arabidopsis and characterize a family of six nucleotide sugar transporters that has never before been described,” says Henrik Scheller, the leader of JBEI’s Feedstocks Division and a leading authority on cell wall biosynthesis.
“Our method should enable rapid progress to be made in determining the functional role of nucleotide sugar transporters in plants and other organisms, which is very important for the metabolic engineering of cell walls.”
Scheller is the corresponding author, along with Ariel Orellana at the Universidad Andrés Bello, Santiago, Chile, of a paper describing this research in the Proceedings of the National Academy of Sciences (PNAS). The paper is titled “The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis.” The lead authors are Carsten Rautengarten and Berit Ebert, both of whom hold appointments with JBEI, and both of whom, like Scheller, also hold appointments with Berkeley Lab’s Physical Biosciences Division. (See below for the full list of co-authors.)
The sugars in plant biomass represent an enormous potential source of environmentally benign energy if they can be converted into transportation fuels – gasoline, diesel and jet fuel – in a manner that is economically competitive with petroleum-based fuels. One of the keys to success in this effort will be to engineer fuel crops whose cells walls have been optimized for sugar content.
With the exception of cellulose and callose, the complex polysaccharide sugars in plant cell walls are synthesized in the Golgi apparatus by enzymes called glycosyltransferases. These polysaccharides are assembled from substrates of simple nucleotide sugars which are transported into the Golgi apparatus from the cytosol, the gel-like liquid that fills a plant cell’s cytoplasm.
Despite their importance, few plant nucleotide sugar transporters have been functionally characterized at the molecular level. A big part of the holdup has been a lack of substrates that are necessary to carry out such characterizations.
“Substrates of mammalian nucleotide sugar transporters are commercially available because of the medical interest but have not been available for plants, which made it difficult to study both nucleotide sugar transporters and glycosyltransferases,” Scheller says.
For their assay, Scheller, Rautengarten, Ebert and their collaborators, created several artificial substrates for nucleotide sugar transporters, then reconstituted the transporters into liposomes for analysis with mass spectrometry. The researchers used this technique to characterize the functions of the six new nucleotide sugar transporters they identified in Arabidopsis, a relative of mustard that serves as a model plant for research in advanced biofuels.
“We found that these six new nucleotide sugar transporters are bispecific, which is a surprise since the two substrates are not very similar from a physical standpoint to the human eye,” Scheller says. “We also found that limiting substrate availability has different effects on different polysaccharide products, which suggests that cell wall polysaccharide biosynthesis in the Golgi apparatus of plants is also regulated by substrate transport mechanisms.”
In addition to these six nucleotide sugar transporters, the assay was used to characterize the functions of 20 other transporters, the details of which will soon be published.
“Thanks largely to the efforts these past two years of Carsten Rautengarten and Berit Ebert, we now know the activity of three times more nucleotide sugar transporters than are known in humans, and we have determined the function of two-thirds of the plant transporters as compared to one-quarter of the human ones,” Scheller says. “This is a tremendous accomplishment and we are already using this information at JBEI to improve biomass sugar composition for biofuel production.”
Other co-authors of the PNAS paper reporting this research were Ignacio Moreno, Henry Temple, Thomas Herter, Bruce Link, Daniela Doñas-Cofré, Adrián Moreno, Susana Saéz-Aguayo, Francisca Blanco, Jennifer Mortimer, Alex Schultink, Wolf-Dieter Reiter, Paul Dupre, Markus Pauly and Joshua Heazlewood.
This research was supported by the DOE Office of Science.
For more about the research of Henrik Scheller go here
For more about the Joint BioEnergy Institute go here
For more about Berkeley Lab’s Physical Biosciences Division go here
# # #
Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.
The DOE 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.
Lynn Yarris | Eurek Alert!
Colorectal cancer risk factors decrypted
13.07.2018 | Max-Planck-Institut für Stoffwechselforschung
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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13.07.2018 | Life Sciences | <urn:uuid:c66a4fe3-4cdb-4542-875e-62924c83b5b8> | 2.75 | 1,906 | Content Listing | Science & Tech. | 30.168474 | 95,643,332 |
When you declare an integer, and the leading digit is a '0', the compiler considers the value to be an Octal representation of the number. So, in your case, it is reading in 12 base 8. When you print it out, it converts it to decimal. so you get 1*8 + 2*1 or 10.
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
you can tell octal numbers because they have the preceding 0 so in your case: int i = 012; this is how it is represented: the 0 tells you its octal, the 1 tells you how many 8's there are, in this case only one, the 2 tells you how many 1's there are, in this case 2, so (8*1) + (1*2)= 10 hope this helps. Davy
How simple does it have to be???
straws are for suckers. tiny ads are for attractive people. | <urn:uuid:f18b2d1e-dbb7-46e2-8d09-26de7c874994> | 3.40625 | 210 | Q&A Forum | Software Dev. | 80.556877 | 95,643,342 |
Friday, May 12, 2017
5 Minute Science Lesson - Wind Turbines
1. Do you know what these are?
2. What do they look like?
3. What do you think they're doing?
4. These are wind turbines. By using the wind, they generate electricity. Where do you think these might be located?
5. See that little strip of bare land running in front of all of them? That's a road. See the little black box at the foot of each turbine? That's a generating station that people go into. So how big do you think these turbines are?
(Psst! See the car parked in front of the 8th one down?) | <urn:uuid:df7557c3-068a-4f43-b72c-1b67cdc6edef> | 3.078125 | 146 | Personal Blog | Science & Tech. | 91.586644 | 95,643,353 |
Neutral and Non-Euclidean Geometries
by David C. Royster
Publisher: UNC Charlotte 2000
Number of pages: 145
In this course you are introduced, or re-introduced, to the method of Mathematical Proof. You will be introduced to new and interesting areas in Geometry, with most of the time spent on the study of Hyperbolic Geometry. We will learn one of the Fundamental Theorems of Mathematics that many students never get to see.
Home page url
Download or read it online for free here:
by Roberto Bonola - Open Court Publishing Company
Examines various attempts to prove Euclid's parallel postulate - by the Greeks, Arabs and Renaissance mathematicians. It considers forerunners and founders such as Saccheri, Lambert, Legendre, Gauss, Schweikart, Taurinus, J. Bolyai and Lobachewsky.
by Henry Manning - Ginn and Company
This book gives a simple and direct account of the Non-Euclidean Geometry, and one which presupposes but little knowledge of Mathematics. The entire book can be read by one who has taken the mathematical courses commonly given in our colleges.
by Silvio Levy - Cambridge University Press
Felix Klein discovered in 1879 that the surface that we now call the Klein quartic has many remarkable properties, including an incredible 336-fold symmetry. This volume explores the rich tangle of properties surrounding this multiform object.
by J.W. Cannon, W.J. Floyd, R. Kenyon, W.R. Parry - MSRI
These notes are intended as a relatively quick introduction to hyperbolic geometry. They review the wonderful history of non-Euclidean geometry. They develop a number of the properties that are particularly important in topology and group theory. | <urn:uuid:b1dfabc1-97b4-4cf2-838d-36e3893810f0> | 2.953125 | 382 | Content Listing | Science & Tech. | 41.006984 | 95,643,358 |
Violent Storms South Australia and New South Wales 11th to 13th November 2016
A significant weather event has crossed much of southern and eastern Australia which has impacted South Australia, Victoria, Tasmania, New South Wales, Australian Capital Territory and Queensland in different ways.
The system has been responsible for producing thunderstorms, some of which have caused damage, gales, outbreaks of hot weather, some heavy rainfall, fires and even snow across higher alpine regions.
During Friday, the fast moving weather system produced a few significant thunderstorms across South Australia and there were reports of large hail across parts of north east Adelaide.
Additionally, a weather station at Pinaroo recorded peak wind gusts of 128 km/h between 6.58 pm and 7.05 pm from passing thunderstorms.
Mildura – Victoria 11/11/16
Late Friday between 8.47 pm and 9 pm, a significant thunderstorm passed over Mildura (North West Victoria) dropping 27.4 mm of rain in 13 minutes. This is significant as it represents 2 mm of rain per minute. A closer analysis of this shows that between 8.51 pm and 8.54 pm (3 minutes), 10.8 mm of rain fell or 3 mm per minute and between 8.54 pm and 8.57 pm, another 10 mm of rain fell. Hence for 6 minutes, rainfall rates were in the order of 3 mm per minute.
This was accompanied with gales of 96 km/h. This storm has caused damage across the city with a clean up occurring.
Such a storm of this intensity is unusual given the location of Mildura within a semi arid region of the state.
New South Wales
A storm system passed through the Central West and there are reports of further significant thunderstorm activity Friday night / Saturday morning. Rainfall figures reached 30 to 50 mm across some locations of the Central West.
The system passed through Sydney early Saturday morning but no significant weather occurred. A single thunderclap was heard early Saturday morning being the remnants of storm activity that had reached the coast. Rainfall was not significant with most totals in the order of 10 mm.
Following the morning rainfall, maximum temperatures reached 34 to 35 degrees across much of the city as north west winds increased through the afternoon.
A late afternoon thunderstorm developed off the coast at Broken Bay to Sydney’s north but moved quickly out to sea.
Thunderstorms occurred across the North west slopes of New South Wales and the Upper Hunter Valley and a number of storms were documented by storm chasers. One particular storm passed very close to the town of Narrabri with the airport receiving three wind gusts to 128 km/h between 5.33 and 5.39 pm Saturday afternoon.
Queensland Saturday afternoon
Thunderstorms produced some strong rainfall totals across parts of Brisbane including 67 mm at Mt Nebo Alert and 65 mm at Everton Hills Alert. In Redland, an intense thunderstorm produced 51.4 mm of rain between 3.24 pm and 4 pm which is a period of 36 minutes. Redland received 53.2 mm for the 24 hours to 9 am 13/11/16.
The same system has produced some heavy rainfall across eastern and north eastern Tasmania with the highest figure being 171 mm at Mount St John to 9 am 13/11/16. Additionally, much of northern coastal Tasmania received 54 to 89 mm during the same period.
New South Wales Sunday 13 November
During Sunday, significant weather contrasts featured across New South Wales. In particular, while maximum temperatures reached 28C to 30C across Sydney, very cold air passed over Southern New South Wales thus places such as Albury experienced a cold wintry weather setup with constant showers and maximum temperatures struggling to reach 13C.
The same system has produced snowfall across the Mt Kosciusko region as freezing conditions set in for the passage of the system.
While this was occurring, a large bush fire occurred near Londonderry (North West Sydney) with fire fighters spending a number of hours fighting the blaze. At one stage, a thick plume of smoke emanating from the fire passed over Blacktown and south east blocking the sunlight. The fire was fanned by strong west to south west winds that reached 70 km/h at Penrith and 74 km/h at Badgerys Creek.
The system has produced a weekend of interesting weather contrasts with the one system creating numerous weather features depending on location.
1 – Sydney radar image at 5.48 am 12/11/16. Despite the radar showing this, significant rainfall amounts did not occur.
2 – The Namoi radar at 5.30 pm. The storm at Narrabri is the one of interest as it is known wind gusts reached 128 km/h.
3 – Photo – Developing storm cell of Avalon / Broken Bay. This storm formed on the coastline and developed further as it passed out to sea.
4 and 5 – Photos – Bushfire smoke plumes west from Blacktown fanned by strong winds Sunday afternoon. | <urn:uuid:4b2d8599-9043-4aac-a5dc-3fdb29de12f0> | 2.78125 | 1,028 | News Article | Science & Tech. | 65.809764 | 95,643,362 |
An Indian zoologist has found a new species of limbless lizard in a forested area in the country's east.
"Preliminary scientific study reveals that the lizard belongs to the genus Sepsophis," said Sushil Kumar Dutta, who led a team of researchers from "Vasundhra," a non-governmental organization, and the North Orissa University.
The newly found 18-centimeter (7-inch) long lizard looks like a scaly, small snake, Dutta said. "It prefers to live in a cool retreat, soft soil and below stones."
"The lizard is new to science and is an important discovery. It is not found anywhere else in the world," Dutta told The Associated Press. He is the head of the zoology department of the North Orissa University in the eastern Indian town of Baripada.
While modern snakes and lizards are derived from a common evolutionary ancestor, they belong today to two entirely separate groups of animals, or orders. Snakes, over millenia, gradually lost their limbs and developed their characteristic forms of locomotion. But modern limbless lizards are not snakes, Dutta said.
The lizard was found 10 days ago during a field study in the forested region of Khandadhar near Raurkela in Orissa state, about 1,000 kilometers (625 miles) southeast of New Delhi, he said.
"The new species will be scientifically described at a later stage after accumulation of more data," Dutta said.
The other limbless lizards belonging to different families have been found in India's Nicobar island, in the northeast, and in Orissa and Andhra Pradesh states, he said.
The closest relatives of the new species are found in Sri Lanka and South Africa, Dutta said.
However, the species found ten days ago is new to the world, Dutta said.
Another species of the same genus, "Sepsohis punctatus," was found in 1870 from the Golconda hills in Andhra Pradesh, said Varadi Giri, a scientist at the Bombay Natural History Society, who was not part of the team that found the lizard. Giri said Dutta is a reputed zoologist and his claim appears legitimate. "But for an independent confirmation, one has to wait for the publication of the finding in a reputed science magazine."
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Elementary Number Theory: Primes, Congruences, and Secrets
by William Stein
Publisher: Springer 2004
Number of pages: 166
This is a textbook about prime numbers, congruences, basic public-key cryptography, quadratic reciprocity, continued fractions, elliptic curves, and number theory algorithms. We assume the reader has some familiarity with groups, rings, and fields, and some programming experience. This book grew out of an undergraduate course that the author taught at Harvard University in 2001 and 2002.
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by William Edwin Clark - University of South Florida
One might think that of all areas of mathematics arithmetic should be the simplest, but it is a surprisingly deep subject. It is assumed that students have some familiarity with set theory, calculus, and a certain amount of mathematical maturity.
by Leo Moser - The Trillia Group
The book on elementary number theory: compositions and partitions, arithmetic functions, distribution of primes, irrational numbers, congruences, Diophantine equations; combinatorial number theory, and geometry of numbers.
by Thomas Taylor, A. J. Valpy
The substance of all that has been written on this subject by Nicomachus, Iamblichus, and Boetius, together with some particulars respecting perfect, amicable, and other numbers, which are not to be found in the writings of modern mathematicians.
by Wissam Raji - The Saylor Foundation
These are notes for an undergraduate course in number theory. Proofs of basic theorems are presented in an interesting and comprehensive way that can be read and understood even by non-majors. The exercises broaden the understanding of the concepts. | <urn:uuid:b2bdbf20-d14d-4c63-ab17-1ebd49bd115a> | 2.875 | 359 | Content Listing | Science & Tech. | 26.019191 | 95,643,400 |
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The InterPlanetary Network (IPN) is a group of spacecraft equipped with gamma ray burst (GRB) detectors. By timing the arrival of a burst at several spacecraft, its precise location can be found. The precision for determining the direction of a GRB in the sky is improved by increasing the spacing of the detectors, and also by more accurate timing of the reception. Typical spacecraft baselines of about one AU (astronomical unit) and time resolutions of tens of milliseconds can determine a burst location within several arcminutes, allowing follow-up observations with other telescopes.
Gamma rays are too energetic to be focused with mirrors. The rays penetrate mirror materials instead of reflecting. Because gamma rays cannot be focused into an image in the traditional sense, a unique location for a gamma ray source cannot be determined as it is done with less energetic light.
In addition, gamma ray bursts are brief flashes (often as little as 0.2 seconds) that occur randomly across the sky. Some forms of gamma ray telescope can generate an image, but they require longer integration times, and cover only a fraction of the sky.
Once three spacecraft detect a GRB, their timings are sent to the ground for correlation. A sky position is derived, and distributed to the astronomical community for follow-up observations with optical, radio, or spaceborne telescopes.
Iterations of the IPN
Note that, since any IPN must consist of several spacecraft, the boundaries between networks are defined differently by different commentators.
Spacecraft naturally join or leave service as their missions unfold, and some modern spacecraft are far more capable than prior IPN members.
A "planetary network"
The Vela group of satellites was originally designed to detect covert nuclear tests, possibly at the Moon's altitude. Thus, the Velas were placed in high orbits, so that a time delay would occur between spacecraft triggers. In addition, each satellite had multiple gamma-ray detectors across their structures; the detectors facing a blast would register a higher gamma count than the detectors facing away.
A gamma-ray burst was detected by the Vela group on June 3, 1969, and thus referred to as GRB 690603. The location was determined to be clearly outside of the satellites' orbit, and probably outside of the Solar system. After reviewing archived Vela data, a previous burst was determined to have occurred on July 2, 1967. Public reports of initial GRBs were not disclosed until the early 1970s.
Additional spacecraft were given gamma-ray detectors. The Apollo 15 and 16 missions carried detectors to study the Moon; middle-to-late Venera spacecraft carried detectors to Venus. The relatively long baselines of these missions again showed that bursts originated at great distances. Other spacecraft (such as the OGO, OSO, and IMP series) had detectors for Earth, Solar, or all-sky gamma radiation, and also confirmed the GRB phenomenon.
The first true IPN
Scientists began to tailor instruments specifically for GRBs. The Helios-2 spacecraft carried a detector with precision time resolution to a Solar orbit that took it over one AU from Earth. Helios-2 was launched in 1976.
In 1978, multiple spacecraft were launched, forming the necessary baselines for a position determination. The Pioneer Venus Orbiter and its Soviet counterparts, Venera 11 and 12, took gamma detectors to the orbit of Venus. In addition, the spacecraft Prognoz-7 and ISEE-3 remained in Earth orbit. These formed an Earth-Venus-Sun triangle, and the probes at Venus formed a smaller triangle. 84 bursts were detected, until the network degraded in 1980. The Pioneer Venus Orbiter continued until it entered the Venus atmosphere in 1992, but not enough other spacecraft were functioning to form the required baselines.
On March 5 and 6, 1979, two bursts of hard X-rays were detected from the same source in the constellation Dorado by the γ-ray burst detector Konus, on the Venera 11 and Venera 12 spacecraft. These X-ray bursts were detected by several other spacecraft. As part of the InterPlanetary Network (IPN), Venera 11, Venera 12 were hit by the March 5, 1979, hard X-ray burst at ~10:51 EST, followed 11 s later by Helios 2 in orbit around the Sun, then the Pioneer Venus Orbiter at Venus. Seconds later the Vela satellites, Prognoz 7, and the Einstein Observatory in orbit around Earth were inundated. The last satellite hit was the ISEE-3 before the burst exited the Solar System.
The second IPN
Pioneer Venus Orbiter was rejoined by Ulysses in 1990. The launch of the Compton Gamma-Ray Observatory in 1991 again formed triangular baselines with PVO and Ulysses. Ulysses continued until June 2009, and the PVO mission ended in August 1992.
Compton once again brought directional discrimination with the BATSE instrument. Like the Velas, BATSE placed detectors at the spacecraft corners. Thus, Compton alone could determine a coarse burst location, to within 1.6 to 4 degrees. Baselines with other spacecraft were then used to sharpen Compton's position solutions. In addition, almost half the sky from Compton was blocked by the Earth, just as Venus blocked part of the sky for PVO. Detection or non-detection by Compton or PVO added another element to the location algorithms.
Compton also had high-precision, low-field-of-view gamma instruments. Occasionally, GRBs would occur where Compton happened to be pointing. The use of multiple, sensitive instruments would provide much more accuracy than BATSE alone.
The "third" IPN
Compton and Ulysses were joined briefly by Mars Observer in late 1992, before that spacecraft failed. Some feel that Compton provided sufficient continuity, and that the distinction between 2nd, 3rd, and subsequent IPNs is semantic.
Compton and Ulysses were joined by Wind in 1994. Although Wind was in Earth orbit, like Compton, its altitude was very high, thus forming a short but usable baseline. The high altitude also meant that Earth blockage was negligible. In addition, Wind carried a top and bottom detector. Interpolation between the two units usually gave a general sky direction for bursts, which in many cases could augment the IPN algorithm. The addition of RXTE in 1995 also helped. Although RXTE was an X-ray mission in Earth orbit, it could detect those gamma-ray bursts which also shone in X-rays, and give a direction (rather than merely a time trigger) for them.
Two important developments occurred in 1996. NEAR was launched; its trajectory to an asteroid again formed a triangular IPN measured in AUs. The IPN was also joined by BeppoSAX. BeppoSAX had wide-field gamma detectors, and narrow-field X-ray telescopes. Once a GRB was detected, operators could spin the spacecraft within hours to point the X-ray telescopes at the coarse location. The X-ray afterglow would then give a fine location. In 1997, the first fine location allowed detailed study of a GRB and its environ.
Compton was deorbited in 2000; the NEAR mission was shut down in early 2001. In late 2001, the Mars Odyssey spacecraft again formed an interplanetary triangle.
Other members of the network include or have included the Indian SROSS-C2 spacecraft, the US Air Force's Defense Meteorological Satellites, the Japanese Yohkoh spacecraft, and the Chinese SZ-2 mission. These have all been Earth orbiters, and the Chinese and Indian detectors were operational for only a few months.
Of all the above, Ulysses is the only spacecraft whose orbit takes it large distances away from the ecliptic plane. These deviations from the ecliptic plane allow more precise 3-D measurements of the apparent positions of the GRBs.
The 21st century: staring spacecraft
New techniques and designs in high-energy astronomy spacecraft are challenging the traditional operation of the IPN. Because distant probes require sensitive ground antennas for communication, they introduce a time lag into GRB studies. Large ground antennas must split time between spacecraft, rather than listen continuously for GRB notifications. Typically, GRB coordinates determined by deep space probes are distributed many hours to a day or two after the GRB. This is very frustrating for studies of events which are measured in seconds.
A new generation of spacecraft are designed to produce GRB locations on board, then relay them to the ground within minutes or even seconds. These positions are based not on time correlation, but on X-ray telescopes, as on BeppoSAX but much faster. HETE-2, launched in 2000, stares at a large region of sky. Should a GRB trigger the gamma detectors, X-ray masks report sky coordinates to ground stations. Because HETE is in a low, consistent orbit, it can use many inexpensive ground stations. There is almost always a ground station in view of the spacecraft, which reduces latency to seconds.
The Swift spacecraft, launched in 2004, is similar in operation but much more powerful. When a GRB triggers the gamma detectors, generating a crude position, the spacecraft spins relatively rapidly to use its focusing X-ray and optical telescopes. These refine the GRB location to within arcminutes, and often within arcseconds. The fine position is reported to the ground in approximately an hour.
INTEGRAL is a successor to Compton. INTEGRAL can similarly determine a coarse position by comparing gamma counts from one side to another. It also possesses a gamma-ray telescope with an ability to determine positions to under a degree. INTEGRAL cannot pivot rapidly like the small HETE and Swift spacecraft. But should a burst happen to occur in its telescope field of view, its position and characteristics can be recorded with high precision.
RHESSI was launched in 2002 to perform solar studies. However, its gamma instrument could detect bright gamma sources from other regions of the sky, and produce coarse positions through differential detectors. Occasionally, a GRB would appear next to the Sun, and the RHESSI instrument would determine its properties without IPN assistance.
Note however, that all these spacecraft suffer from Earth blockage to varying degrees. Also, the more sophisticated the "staring" instrument, the lower the sky coverage. Randomly occurring GRBs are more likely to be missed, or detected at low resolution only. The use of non-directional deep space probes, such as MESSENGER and BepiColombo, will continue.
Current IPN developments
In 2007 AGILE was launched and in 2008 the Fermi Gamma-ray Space Telescope and although these are Earth orbiters, their instruments provide directional discrimination. The Fermi Space Telescope uses both wide-area burst detectors and a narrow-angle telescope, and has a limited ability to spin itself to place a GRB within the telescope field. MESSENGER's Gamma Ray Neutron Spectrometer was able to add data to the IPN, before the end of MESSENGER's mission in 2015. Due to falling power from its RTG, Ulysses was decommissioned on June 30, 2009.
- Mazets EP, Golenetskii SV, Il'inskii VN, Aptekar' RL, Guryan YA (December 1979). "Observations of a flaring X-ray pulsar in Dorado". Nature. 282 (5739): 587–9. Bibcode:1979Natur.282..587M. doi:10.1038/282587a0.
- Morgan M. "InterPlanetary Network Progress Report".
- Talbert, Tricia (2015-04-15). "Spacecraft and Instruments". NASA. Retrieved 2018-04-01.
- Hurley, K. et. al (2013). "The Interplanetary Network Supplement to the Fermi GBM Catalog of Cosmic Gamma-Ray Bursts". arXiv: . | <urn:uuid:f9089796-901f-491d-9fef-0c25644ff59e> | 4.1875 | 2,530 | Knowledge Article | Science & Tech. | 44.319339 | 95,643,404 |
Authors: Bader Binkhudhayr
Our understanding of motion has been influenced by the assumption that external and invisible forces act upon matter to cause acceleration. In this article, I refute the validity of this convention and propose an alternative perception that suggests matter's independence. That change in perspective gives rise to important principles and equations that contribute to resolving the conflict between classical and quantum mechanics, unifying the explanations for universal forces and explaining the Lorentz transformation. I start by introducing a unit, a number of fundamental particles, that replaces mass. Then, I suggest that motion is quantized with a frequency equal to speed divided by a variation of Planck's Length. Finally, I introduce a single formula that describes gravity and electromagnetism.
Comments: 16 Pages.
Unique-IP document downloads: 48 times
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Turbulenz – ein problemhistorischer Abriss
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Schlüsselwörter:Turbulenz Strömungsforschung Technowissenschaften L. Prandtl von Kármán G. I. Taylor
Turbulence in Perspective
In the beginning of the 20th century, the riddles of turbulent flow became articulated as “the turbulence problem”. It comprised two parts: the onset of turbulence, which was conceived as an instability of laminar flow; and fully developed turbulence, for which both empirical (mixing length) and statistical theories of turbulence were developed. Up until the present time turbulence research has been inter-and transdisciplinary, attracting scientists and engineers from a variety of specialties and with diverse scientific and technological orientations. For this reason, turbulence research is also an interesting case for the sociological study of knowledge production in technoscience.
The article traces the history of the turbulence problem in the first half of the 20th century, when the major pathways for its attack were first outlined and explored. The ups and downs of the turbulence problem in different local and cultural settings provide a unique opportunity to study a technoscience in the making, beyond sweeping assumptions about science-technology relations. Present fluid dynamicists rate the turbulence problem still as unsolved, but this evaluation should not prevent historians of science and technology from tackling it by their own means: it safeguards the historical analysis against the pitfall of whig history.
Keywords:turbulence fluid dynamics technoscience L. Prandtl von Kármán G. I. Taylor
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Thanks to a new high-tech gadget, astronomers have observed four planets orbiting a star relatively close to the sun in unprecedented detail, revealing the roughly ten-Jupiter-mass planets to be among the most exotic ones known.
In this image of the star HR 8799, most of the light from the star itself has been removed, leaving behind a "speckle" pattern of light. The Project 1640 instrument then removes the speckles to reveal the planets previously hidden in the glare. Credit: Project 1640
The team, which includes several researchers from the California Institute of Technology (Caltech), describes its findings in a paper accepted for publication by the Astrophysical Journal.
The findings were made possible by a first-of-its-kind telescope imaging system that allowed the astronomers to pick out the planets amidst the bright glare of their parent star and measure their spectra—the rainbows of light that reveal the chemical signatures of planetary atmospheres. The system, dubbed Project 1640, enables astronomers to observe and characterize these kinds of planetary systems quickly and routinely, which has never been done before, the researchers say.
"These warm, red planets are unlike any other known objects in our universe," says Ben R. Oppenheimer, an astronomer at the American Museum of Natural History and the paper's lead author. And the planets are very different from one another as well. "All four planets have different spectra and all four are peculiar."
Astronomers had previously taken images of these four planets, which orbit a star called HR 8799, located 128 light years away. But because a star's light is tens of millions to billions of times brighter than the light from that star's own planets, distinguishing planet light from starlight so as to directly measure the spectra from the planets alone is difficult. "It's like taking a single picture of the Empire State Building from an airplane that reveals the height of the building but also a bump on the sidewalk next to it that is as high as a couple of bacteria," Oppenheimer explains. "Furthermore, we've been able to do this over a range of wavelengths in order to make a spectrum."
In the past, astronomers have been able to take spectra of some planets that pass in front of, or transit, their stars. But with Project 1640, which uses the Hale Telescope at Caltech's Palomar Observatory in Southern California, astronomers can now take the direct spectra of planets orbiting other stars—called exoplanets—that are not transiting. The device blocks the otherwise overwhelming starlight, picks out the faint specks that are planets, and obtains their spectra. Project 1640 allowed the team to take spectra of all four of the planets around HR 8799 simultaneously, which had never been done for any planetary system before.
The planets around HR 8799 are at about the same distance from that star as the solar system's gas giants (Jupiter, Saturn, Uranus, and Neptune) are from our sun. But since it's easier to detect transiting planets that are close to their stars, the transiting systems that astronomers have observed have small orbits—often smaller than Mercury's. The new results, therefore, represent the first spectra to be taken of gas giants located so far from their stars—a distance at which the influence of the stars' radiation, flares, and other features are weaker.
"We are now technically capable of obtaining spectra of giant planets in planetary systems like our own, improving on the close-in transiting planet studies done previously," says Lynne Hillenbrand, professor of astronomy at Caltech and a coauthor of the paper. And what the spectra show is that the planets are quite strange. "A remarkable thing about these planets is their unexpected spectroscopic diversity," Hillenbrand says.
One of the most striking abnormalities is an apparent chemical imbalance. Under most circumstances, ammonia and methane should naturally coexist in a planet's atmosphere—where there is one, there is usually the other—unless they are generated in extremely cold or hot environments. Yet the spectra of the HR 8799 planets, all of which have "lukewarm" temperatures of about 1000 Kelvin (1340 degrees Fahrenheit), either have methane or ammonia alone, with little or no sign of their chemical partner. There is also evidence of other chemicals such as acetylene—which has never before been detected on any exoplanet—and carbon dioxide.
The planets also are "redder"—they emit longer wavelengths of light—than celestial objects with similar temperatures. This could be explained by the presence of significant but patchy cloud cover on the planets, the authors say.
HR 8799 itself is very different from our sun, with 1.6 times its mass and five times its brightness. The brightness of this distant star can vary by as much as 8 percent over a period of two days; it produces about 1,000 times more ultraviolet light than the sun. All of these factors could induce complex weather and sooty hazes that would, in turn, cause periodic changes in the spectra.
More data are needed to further explore this solar system's unusual characteristics, the scientists say.
"The spectra of these four worlds clearly show that they are far too toxic and hot to sustain life as we know it," says coauthor Ian Parry, a senior lecturer at the Institute of Astronomy, Cambridge University. "But the really exciting thing is that, one day, the techniques we've developed will give us our first secure evidence of the existence of life on a planet outside our solar system."
The techniques used by Project 1640 require the coordinated operation of four major instruments: the world's most advanced adaptive-optics system, which can make millions of tiny adjustments to the device's two six-inch mirrors every second; a coronagraph that optically dims the star but not other celestial objects in the field of view; an imaging spectrograph that records 30 images in a rainbow of colors simultaneously; and a specialized wavefront sensor that distinguishes between residual starlight that sneaks through the coronagraph and light from planets, allowing scientists to filter out background starlight more effectively.
With these instruments working in concert, the project is able to reveal celestial objects 1 million to 10 million times fainter than the star at the center of one of its images, with only an hour of observations. It is also capable of measuring the orbital motion of objects.
"Our young century has seen seminal advances in exoplanet science, but almost exclusively from indirect observations," says Richard Dekany, a coauthor and associate director for development for Caltech Optical Observatories. "Project 1640 has now added to this revolution the scientific gold standard: directly measured spectra of young giant planets. Our initial findings suggest each of these strange and wonderful giant planets may have a unique story to share."
The researchers are already collecting more data on this system so as to look for changes in the planets over time; they are also surveying other young stars. During its three-year survey at Palomar, which started in June, Project 1640 aims to survey 200 stars within about 150 light years of our solar system.
"In the 19th century, it was thought impossible to know the composition of stars, but the invention of astronomical spectroscopy has revealed detailed information about nearby stars and distant galaxies," says Charles Beichman, executive director of the NASA Exoplanet Science Institute at Caltech. "Now, with Project 1640, we are beginning to turn this tool to the investigation of neighboring exoplanets to learn about the composition, temperature, and other characteristics of their atmospheres."
The title of the the Astrophysical Journal paper is "Reconnaissance of the HR 8799 exosolar system I: Near IR spectroscopy." In addition to Hillenbrand, Dekany, and Beichman, the other Caltech authors are postdocs Christoph Baranec and Sasha Hinkley; former postdoc Justin Crepp (now at the University of Notre Dame); and programmer David Hale, along with a similar number of JPL authors. This work was supported by the National Science Foundation and NASA. Additional funding sources for Project 1640 are listed here.This story is adapted from a press release by Kendra Snyder of the American Natural History Museum.
Deborah Williams-Hedges | EurekAlert!
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
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16.07.2018 | Life Sciences
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Protection of the Environment through Power from Space: Science Fiction or Future Reality?
All energy sources on Earth — except the nuclear ones — derive their energy from the Sun. For comfort and a high living standard people need a considerable amount of energy. More than 80% of the World’s consumption of energy is covered by fossil fuel, a nonrenewable resource which will be exhausted in the long run. This will happen faster when and if the whole world population, on average, gets an energy standard similar to that currently enjoyed by the industrial countries. The need for replacement of a large portion of the fossil power may however come much earlier if it is finally proven without doubt that the anthropogenic greenhouse effect leads to a significant warming of the global climate — or if it is decided that, despite the absence of absolute proof, the risk of such global warming should not be taken. In that case the incentive strengthens considerably to develop alternatives, such as improved versions of nuclear power and, perhaps, photovoltaic power from Space. Nuclear power has its well-known problem of public acceptance. If that cannot be solved in a convincing way, the interest in the remaining possibilities will increase further with improving chances for power from Space. Although a majority of scientists seem to adhere to the belief that a future global warming of the climate will occur due to the anthropogenic emissions of the greenhouse gases and that action should be taken today to reduce these emissions, a minority of experts remain sceptical. Because of the importance for our subject of this question, we give below a highly condensed summary of the most relevant facts and judgments.
KeywordsGreenhouse Effect Science Fiction Power Conditioning Photovoltaic Power Future Global Warming
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The researchers concluded that models of climate change may be underestimating how much water is likely to run off the land and back into the sea as atmospheric chemistry changes. Runoff may be as much as 17 percent higher in forests of the eastern United States when models account for changes in soil nitrogen levels and atmospheric ozone exposure.
"Failure to consider the effects of nitrogen limitation and ozone on photosynthesis can lead us to underestimate regional runoff," said Benjamin Felzer, an ecosystem modeler at Lehigh University in Bethlehem, Pa. "More runoff could mean more contamination and flooding of our waterways. It could also mean fewer droughts than predicted for some areas and more water available for human consumption and farming. Either way, water resource managers need more accurate runoff estimates to plan better for the changes."
Felzer and colleagues from the Massachusetts Institute of Technology (MIT) in Cambridge and the Marine Biology Laboratory in Woods Hole, Mass., published their findings recently in the Journal of Geophysical Research – Biogeosciences.
Plants play a significant role in Earth's water cycle, regulating the amount of water cycling through land ecosystems and how long it stays there. Plants draw in water from the atmosphere and soil, and they discharge it naturally through transpiration, the tail end of photosynthesis when water vapor and oxygen are released into the air.
The amount of water that plants give up depends on how much carbon dioxide is present in the atmosphere. Studies have shown that despite a global drop in rainfall over land in the past 50 years, runoff has actually increased.
Other studies have shown that increasing CO2 is changing how plant "pores," or stomata, discharge water. With elevated CO2 levels, leaf pores contract and sometimes close to conserve internal water reserves. This "stomatal conductance" response increases water use efficiency and reduces the rate of transpiration.
Plants that release less water also take less of it from the environment. With less water being taken up by plants, more water is available for groundwater or runs off the land surface into lakes, streams, and rivers. Along the way, it accumulates excess nutrients and pollutants before emptying into waterways, where it affects the health of fish, algae, and shellfish and contaminate drinking water and beaches. Excess runoff can also contribute to flooding.
Sometimes rising CO2 has the opposite effect, Felzer noted, promoting vegetation growth by increasing the rate of photosynthesis. More plant growth can lead to a thicker canopy of leaves with increased transpiration and less runoff. However, this effect has been shown to be smaller than the effect of reduced stomatal conductance.
Aware of these cycles, Felzer and colleagues used theoretical models to project various future scenarios for the amount of carbon dioxide in the atmosphere and what it would mean to the changing water cycle in forests east of the Mississippi River. They found that runoff would increase anywhere from 3 to 6 percent depending on location and the amount of the increase in CO2.
Felzer and colleagues also examined the role of two other variables -- atmospheric ozone and soil-based nitrogen -- in the changing water cycle. Excess ground-level ozone harms the cells responsible for photosynthesis. Reductions in photosynthesis leads to less transpiration and cycling of water through leaves and more water added to runoff.
In most boreal and temperate forests, the rate of photosynthesis is also limited by the availability of nutrients such as nitrogen in the soil. The less nitrogen in the soil, the slower their rate of photosynthesis and transpiration.
"The increase in runoff is even larger when nitrogen is limited and environments are exposed to high ozone levels," said Felzer. In fact, the team found an additional 7 to 10 percent rise in runoff when nitrogen was limited and ozone exposure increased.
"Though this study focuses on Eastern U.S. forests, we know nitrogen and ozone effects are also important in South America and Europe. One region has seen a net increase and the other a net runoff reduction," said co-author Adam Schlosser of the Center for Global Change Science at MIT. "Our environment and quality of life depend on less uncertainty on this front."Written by:
Sarah DeWitt | 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
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering | <urn:uuid:50969391-72ac-4c30-b32e-2e6671f23606> | 3.796875 | 1,485 | Content Listing | Science & Tech. | 36.485174 | 95,643,453 |
There is still a widespread belief that microscopic organisms, such as bacteria, fungi, protists, and small multicellulars, have a cosmopolitan distribution due to a presumed easy dispersal by wind and water. However, the contributions collected in this book – ranging from protists to rotifers and mosses – show that microorganisms have community structures and biogeographies similar to those found in animals and vascular plants, although the ranges of many can be wider and local endemism is rarer. Accordingly, the cosmopolitan distribution model of Finlay & Fenchel is to be replaced by the moderate endemicity model of Foissner, which assumes that one third of microscopic organisms are morphological and/or genetic endemics. This has far-reaching consequences for estimates of the number of species and their conservation. There is convincing evidence that we know only about 20% of the actual diversity in many protist groups, especially saprotrophs and heterotrophs such as amoebae, flagellates, and ciliates. It is probable that this great diversity of microscopic organisms is caused by low extinction rates over geological time, and short generation times which foster dispersal of genetic variants. That the great diversity of microorganisms has remained unrecognized for such a long time has several reasons, of which the most serious is a shortage of taxonomists. Considering the dramatic losses of habitats occurring, especially in the tropics, a large portion of the Earth’s protist biodiversity will disappear before it has been discovered.
Reprinted from Biodiversity and Conservation, volume 17:2 (2008)
Ecologists, university teachers, biodiversity postgraduate students and scientists, conservation biologists and taxonomists
Protist diversity and distribution: some basic considerations; Foissner.- Distribution and diversity of aquatic protists: an evolutionary and ecological perspective; Weisse.- "Missing" protists: a molecular perspective; Epstein.- Diversity, dispersal and biogeography of bryophytes (mosses); Frahm.- Myxomycete diversity and distribution from the fossil record to the present; Stephenson.- Diversity and endemism in Rotifera: a review, and Keratella Bory de St Vincent; Segers.- Diversity and geographic distribution of benthic foraminifera: a molecular perspective; Pawlowski.- Diversity and biogeography of testate amoebae; Smith.- Diversity and geographic distribution of ciliates (Protista: Ciliophora); Foissner.- The "Tetrahymena pyriformis" complex of cryptic species; Simon.- Diversity and geographic distribution of desmids and other coccoid green algae; Coesel.- The diversity and distribution of diatoms: from cosmopolitanism to narrow endemism; Vanormelingen.- Dinoflagellate diversity and distribution; Taylor.- Dispersal and biogeography of silica-scaled chrysophytes; Kristiansen.- Conservation of protists: is it needed at all?; Cotterill. | <urn:uuid:40ce1e35-c5a5-4397-881b-0f6d0dcf0951> | 3.46875 | 641 | Content Listing | Science & Tech. | 5.92352 | 95,643,454 |
Great Lakes Research Center Seminar Series: W. Charles Kerfoot of the Lake Superior Ecosystem Research Center & Department of Biological Sciences,
Michigan Technological University
LiDAR and MSS Applications For Coastal Ecosystem Research & Restoration Projects
Description: Due to its high spatial resolution and excellent water penetration, LiDAR and multi‐spectral imaging (MSS) has great promise for resolving shoreline environmental issues. Grand (Big) Traverse Bay on the Keweenaw Peninsula has provided an excellent Great Lakes example of the consequences of mine discharges into coastal environments. Although coastal discharge is currently advocated by mining in ocean environments as the "out of sight, out of mind" alternative to "tailing impoundments", modern improvements in remote sensing can track coastal discharges. For over a century, waste rock migrating from shoreline tailings piles has moved along extensive stretches of the Keweenaw coastline, damming stream outlets, intercepting wetlands and recreational beaches, suppressing benthic invertebrate communities, and threatening critical fish breeding grounds. Here we use LiDAR and MSS imagery to estimate the time course and mass of tailings eroded into Grand Traverse Bay and to quantify underwater tailings spread across benthic substrates. We show that the coastal detail from LiDAR and MSS opens up numerous applications for ecological, ecosystem, and geological investigations. Initial studies aided the establishment of an authorized $8‐9M USACE Stamp Sand Restoration Project in Grand Traverse Bay. | <urn:uuid:617cc881-5537-4fcd-8702-caef5c575101> | 2.75 | 305 | Audio Transcript | Science & Tech. | 3.470738 | 95,643,467 |
Determine the secret number n, which reversed decrease by 16.4 if the number increase by 16.4.
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Solve for x: 3(x + 2) = x - 18 | <urn:uuid:9ed1ea82-72ad-4f38-a772-34882a6c751f> | 2.953125 | 571 | Tutorial | Science & Tech. | 79.643205 | 95,643,474 |
By: Denise Chow, SPACE.com Contributor
Published: 04/25/2013 10:43 AM EDT on SPACE.com
The sun has unleashed a trio of solar eruptions toward the planet Mercury in recent days, solar storms that may pass one NASA spacecraft while dealing a glancing blow to another, NASA officials say.
The three flares erupted from the sun over the span of two days, and belched waves of plasma and charged particles — called coronal mass ejections (CMEs) — that are now heading toward Mercury, NASA officials said in a statement.
This image of a coronal mass ejection (CME) was captured on April 20, 2013. The CME is headed in the direction of Mercury. The large bright spot on the left is Venus.
The combined CMEs are expected to pass the agency's Messenger probe, which has been orbiting the planet closest to the sun since March 2011, but may deliver a glancing blow to the Stereo-A spacecraft, which circles Earth while training its eyes on the sun.
"The Messenger and Stereo mission operators have been notified," NASA officials wrote in an update. "There may be some particle radiation associated with this event, which in the worst case scenario can impact computer electronics on board interplanetary spacecraft. If warranted, operators can put spacecraft into safe mode to protect the instruments from the solar material." [Amazing Solar Storms of 2013 (Photos)]
The first CME erupted at 2:54 a.m. EDT (0655 GMT) on April 20. Two additional CMEs followed the next day, at 3:54 a.m. EDT (0754 GMT) and 12:39 p.m. EDT (1639 GMT). All three clouds of superhot plasma were blasted from the sun at speeds greater than 1.8 million miles per hour (2.9 million kilometers per hour).
When aimed directly at Earth, the strongest solar flares and eruptions can pose a threat to satellites and astronauts in space, and interfere with navigation, communication and power infrastructure on the surface.
NASA's Stereo-A is one of a pair of twin space probes that monitor solar weather events. The Stereo spacecraft (short for Solar Terrestrial Relations Observatory) were launched in 2006.
The Messenger spacecraft completed the first full map of Mercury's surface last month. The probe's primary mission ran through March 2012, but was granted a one-year extension.
The sun's activity ebbs and flows on an 11-year cycle, and solar weather events are expected to increase this year as the current cycle ramps up toward the solar maximum. The current solar weather cycle is known as Solar Cycle 24. | <urn:uuid:a850f3fb-6f79-4164-ab8e-e324d611bcf3> | 3.28125 | 551 | Truncated | Science & Tech. | 60.359884 | 95,643,475 |
+44 1803 865913
By: RR Reeves
123 pages, Figs, tabs
Important contribution to the ongoing controversies over the Sakhalin Island oil and gas development project.
From the publisher's announcement:
The population of western gray whales numbers only about 100 animals and is classified on IUCN's Red List as `critically endangered'. Under the auspices of IUCN, an independent scientific review panel was established to evaluate scientific aspects of western gray whale conservation in the context of Phase 2 of the Sakhalin II, an integrated oil and gas project being developed by the Sakhalin Energy Investment Company under a production sharing agreement with the Russian Federation and its Sakhalin Oblast. This report of the Panel provides a detailed consideration of the risks, the options for mitigation and the need for monitoring if and as oil and gas development proceeds.
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#include <pcap/pcap.h> void pcap_breakloop(pcap_t *);
This routine is safe to use inside a signal handler on UNIX or a console control handler on Windows, as it merely sets a flag that is checked within the loop.
The flag is checked in loops reading packets from the OS - a signal by itself will not necessarily terminate those loops - as well as in loops processing a set of packets returned by the OS. Note that if you are catching signals on UNIX systems that support restarting system calls after a signal, and calling pcap_breakloop() in the signal handler, you must specify, when catching those signals, that system calls should NOT be restarted by that signal. Otherwise, if the signal interrupted a call reading packets in a live capture, when your signal handler returns after calling pcap_breakloop(), the call will be restarted, and the loop will not terminate until more packets arrive and the call completes.
Note also that, in a multi-threaded application, if one thread is blocked in pcap_dispatch(), pcap_loop(), pcap_next(3PCAP), or pcap_next_ex(3PCAP), a call to pcap_breakloop() in a different thread will not unblock that thread. You will need to use whatever mechanism the OS provides for breaking a thread out of blocking calls in order to unblock the thread, such as thread cancellation or thread signalling in systems that support POSIX threads, or SetEvent() on the result of pcap_getevent() on a pcap_t on which the thread is blocked on Windows. Asynchronous procedure calls will not work on Windows, as a thread blocked on a pcap_t will not be in an alertable state.
Note that pcap_next() and pcap_next_ex() will, on some platforms, loop reading packets from the OS; that loop will not necessarily be terminated by a signal, so pcap_breakloop() should be used to terminate packet processing even if pcap_next() or pcap_next_ex() is being used.
pcap_breakloop() does not guarantee that no further packets will be processed by pcap_dispatch() or pcap_loop() after it is called; at most one more packet might be processed.
If -2 is returned from pcap_dispatch() or pcap_loop(), the flag is cleared, so a subsequent call will resume reading packets. If a positive number is returned, the flag is not cleared, so a subsequent call will return -2 and clear the flag. | <urn:uuid:a9614783-914a-4a23-90be-a60b60580a8c> | 2.53125 | 549 | Documentation | Software Dev. | 40.305174 | 95,643,496 |
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Found most commonly in these habitats: 61 times found in rainforest, 5 times found in secondary lowland rainforest, 10 times found in premontane rainforest, 6 times found in montane wet forest, 2 times found in lowland rainforest, 2 times found in Dry sclerophyll, 2 times found in Primary forest, 7 times found in Bamboo forest, 3 times found in pasture/cloud forest edge, 3 times found in primary lowland rainforest, ...
Found most commonly in these microhabitats: 44 times ex sifted leaf litter, 0 times Sieved litter, 6 times mercury vapor lamp, 2 times Litter, 5 times under stone, 5 times Malaise trap, 6 times ex rotten log, 2 times strays, 3 times random ground foragers, 3 times Nest in rotten log on ground., 3 times Foraging on ground., ...
Collected most commonly using these methods: 1 times Berlesate, 18 times winkler, 27 times search, 24 times maxiWinkler, 11 times blacklight, 2 times Baited pitfall traps, 7 times Malaise, 1 times sweeping, 5 times traps, 0 times Pyrethrum, 0 times at light, ...
Elevations: collected from 1 - 2060 meters, 442 meters average
AntWeb content is licensed under a Creative Commons Attribution License. We encourage use of AntWeb images. In print, each image must include attribution to its photographer and "from www.AntWeb.org" in the figure caption. For websites, images must be clearly identified as coming from www.AntWeb.org, with a backward link to the respective source page. See How to Cite AntWeb.
Antweb is funded from private donations and from grants from the National Science Foundation, DEB-0344731, EF-0431330 and DEB-0842395. c:0 | <urn:uuid:0d09fc22-a4cc-4d17-bf8c-6ae3907fa030> | 2.875 | 415 | Knowledge Article | Science & Tech. | 60.894216 | 95,643,515 |
GEOMAGNETIC STORM WARNING: A pair of closely-spaced CMEs propelled by explosions of sunspot AR1302 on Sept. 24th are heading not-quite directly toward Earth. A significant glancing blow to our planet's magnetic field is possible on Sept. 26th around 14:00 UT (+/- 7 hours). NOAA forecasters estimate a 30% chance of strong geomagnetic storms when the clouds arrive. [CME forecast track] Aurora alerts: text, voice.
STRONG SOLAR ACTIVITY: Having already unleashed two X-flares since Sept. 22nd, sunspot AR1302 appears ready for more. The active region has a complex "beta-gamma-delta" magnetic field that harbors energy for strong M- and X-classeruptions. Flares from AR1302 will become increasingly geoeffective as the sunspot turns toward Earth in the days ahead.
Marko Posavec of Koprivnica, Croatia, photographed the behemoth sunspot between flares on Sept. 24th:
"Sunspot complex 1302 is incredibly easy to spot at sunrise or sunset," says Posavec. "Be careful, though. Even the low-hanging sun is bright enough to damage your eyes if you look at it through optics of any kind." Safe solar filters may be found in the SpaceWeather Store.
More Images: from Alan Friedman of Buffalo, NY; from Monika Landy-Gyebnar of Balatonfured, Hungary; from Piet Berger of Simpelveld, Netherlands; from Howard Eskildsen of Ocala, Florida; from Dzmitry Kananovich of Tallinn, Estonia
SOLAR STATIC: Active sunspot 1302 has turned the sun into a shortwave radio transmitter. Shock waves rippling from the sunspot's exploding magnetic canopy excite plasma oscillations in the sun's atmosphere. The result is bursts of static that may be heard in the loudspeakers of shortwave radios on Earth. Amateur radio astronomer Thomas Ashcraft recorded this sample from his backyard observatory in New Mexico on Sept. 24th:
Dynamic spectrum: The horizontal axis is time (h:m:s), the vertical axis is frequency (MHz). Image credit: Wes Greenman
"Saturday was a super-strong solar day with near continuous flaring and radio sweeps," says Ashcraft. "The sound file (above) corresponds to an M3 flare at 1918 UTC. It was the strongest radio sweep of the observing day."
"Try listening to the radio bursts in stereo," he advises. "I was recording on two separate radios at 21.1 MHz and 21.9 MHz, and I put each one into its own channel of the audio file. This gives a spatial dimension as the bursts sweep down in frequency." | <urn:uuid:aad4df61-307a-4d61-a2fa-74c3e7d50e79> | 2.625 | 583 | Personal Blog | Science & Tech. | 54.057576 | 95,643,523 |
Scientists have long known that solar-energized particles trapped around the planet are sometimes scattered into Earth's upper atmosphere where they can contribute to beautiful auroral displays. Yet for decades, no one has known exactly what is responsible for hurling these energetic electrons on their way. Recently, two spacecraft found themselves at just the right places at the right time to witness first hand both the impulsive electron loss and its cause.
New research using data from NASA's Van Allen Probes mission and FIREBIRD II CubeSat has shown that a common plasma wave in space is likely responsible for the impulsive loss of high-energy electrons into Earth's atmosphere.
Known as whistler mode chorus, these waves are created by fluctuating electric and magnetic fields. The waves have characteristic rising tones -- reminiscent of the sounds of chirping birds -- and are able to efficiently accelerate electrons. The results have been published in a paper in Geophysical Review Letters.
"Observing the detailed chain of events between chorus waves and electrons requires a conjunction between two or more satellites," said Aaron Breneman, researcher at the University of Minnesota in Minneapolis, and lead author on the paper. "There are certain things you can't learn by having only one satellite -- you need simultaneous observations at different locations."
The study combined data from FIREBIRD II, which cruises at a height of 310 miles above Earth, and from one of the two Van Allen Probes, which travel in a wide orbit high above the planet. From different vantage points, they could gain a better understanding of the chain of cause and effect of the loss of these high-energy electrons.
Far from being an empty void, the space around Earth is a jungle of invisible fields and tiny particles. It's draped with twisted magnetic field lines and swooping electrons and ions. Dictating the movements of these particles, Earth's magnetic environment traps electrons and ions in concentric belts encircling the planet. These belts, called the Van Allen Radiation Belts, keep most of the high-energy particles at bay.
Sometimes however, the particles escape, careening down into the atmosphere. Typically, there is a slow drizzle of escaping electrons, but occasionally impulsive bunches of particles, called microbursts, are scattered out of the belts.
Late on Jan. 20, 2016, the Van Allen Probes observed chorus waves from its lofty vantage point and immediately after, FIREBIRD II saw microbursts. The new results confirm that the chorus waves play an important role in controlling the loss of energetic electrons -- one extra piece of the puzzle to understand how high-energy electrons are hurled so violently from the radiation belts. This information can additionally help further improve space weather predictions.
Mara Johnson-Groh | EurekAlert!
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
13.07.2018 | Life Sciences | <urn:uuid:3826a6b9-cd83-4bea-ae4a-e4b306d58e87> | 4.28125 | 1,194 | Content Listing | Science & Tech. | 37.900332 | 95,643,533 |
In a remote area of the Indian Ocean, a tropical storm continues to intensify then weaken only to redevelop making forecasting very challenging.
The named storm is forecast to develop into a weak tropical cyclone over coming days. However only two days ago on February 14, a forecast was made for the storm to develop into a strong Category 3 storm on the Saffir Simpson Scale. That forecast is downgraded significantly and there is even the chance it may not properly transition into a tropical cyclone at all.
The named storm “Uhriah” developed relatively close but south west of Java (Indonesia) and travelled south west but is expected take a more southerly direction over coming days.
The storm has formed over waters of 29C which would support a tropical cyclone however it appears the storm has been significantly affected by sheer which at one stage, almost tore the storm apart. The storm has managed to redevelop after losing much of its structure. It sustains a small but intense core and an eye has been visible in satellite photos.
At the time of writing the storm is situated at latitude 17.9 degrees south and 84.7 degrees east placing it deep within the Indian Ocean with no imminent threat of landfall. It is possible that the storm will not make landfall during its lifespan.
It sustains winds of 55 knots or approximately 102 km/h near the core. It borders on the transition to a tropical cyclone and if it does so, then its maximum strength is expected to be a Category 1 storm throughout its life span with peak winds to 80 knots or 148 km/h.
What makes this storm interesting that despite the sheer that nearly pulls the storm apart, it has maintained some degree of structure over the past 3 or 4 days. Eventually the storm will weaken as it encounters colder waters further south.
1- CIMSS (Forecast plots for Tropical Storm Uhriah) dated 16/2/2016.
2 – NASA (MODIS Worldview satellite image of Uhriah) acquired 16/2/2016. | <urn:uuid:505c1ca4-7a8f-4c32-9c6b-21f68a9b534b> | 2.921875 | 417 | News Article | Science & Tech. | 53.070871 | 95,643,558 |
At a time when life as we know it was just getting its start on Earth, Martian clay may have contained a key component for one of life's molecular building blocks, researchers say.
Boron found in a Martian meteorite suggests that the Red Planet may once have had the right chemistry to give rise to RNA, according to a new study.
"In early life, RNA is thought to have been the informational precursor to DNA," study researcher James Stephenson, an evolutionary biologist, says.
Billions of years ago, RNA may have been the first molecule to program information and pass it on to the next generation. Today, that task is DNA's domain. RNA, meanwhile, is responsible for carrying genetic information from DNA to proteins. Researchers believe the RNA sugar component, ribose, relies on borates (the oxidized form of boron) to form spontaneously.
"Borates may have been important for the origin of life on Earth because they can stabilize ribose, a crucial component of RNA," added Stephenson, who is a postdoctoral fellow at the University of Hawaii at Manoa NASA Astrobiology Institute (UHNAI).
Stephenson and cosmochemist Lydia Hallis, another UHNAI postdoctoral fellow, came up with the idea to look at boron in meteorites over an after-work beer.
"Given that boron has been implicated in the emergence of life, I had assumed that it was well characterized in meteorites," says Stephenson. "Discussing this with Dr. Hallis, I found out that it was barely studied. I was shocked and excited. She then informed me that both the samples and the specialized machinery needed to analyze them were available at UH."
The space rock at the center of the study was collected during the 2009-2010 field season of the Antarctic Search for Meteorites (ANSMET). This annual search aims to find dark rocks embedded in Antarctica's pale landscape that might be extraterrestrial in origin. The project is funded by NASA, the National Science Foundation and the Smithsonian Institution.
Stephenson, Hallis and their colleagues pored over the veins of clay in a meteorite from Mars using the ion microprobe in the W. M. Keck Cosmochemistry Laboratory. They found that the boron concentrations in these clays were more than ten times higher than in any previously measured extraterrestrial object. The findings could also shed light on the early history of Earth, the researchers say.
"Earth and Mars used to have much more in common than they do today," Hallis says. "Over time, Mars has lost a lot of its atmosphere and surface water, but ancient meteorites preserve delicate clays from wetter periods in Mars' history. The Martian clay we studied is thought to be up to 700 million years old. The recycling of the Earth's crust via plate tectonics has left no evidence of clays this old on our planet; hence Martian clays could provide essential information regarding environmental conditions on the early Earth."
While Martian meteorites deliver tantalizing clues about the Red Planet's ancient chemistry, NASA's fleet of Mars rovers, which currently includes Curiosity and Opportunity, have been studying the makeup of Mars dirt on location. Curiosity earlier this year found that Mars could have supported microbial life in the ancient past, based on a sample the one-ton robot drilled out of a Martian rock. That sample contained chemical components thought to be critical to life, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, researchers say.
The new research appeared online June 6 in the journal PLOS One.
Image courtesy of NASA
- Mars Curiosity: Facts and Information
- Jeff Bezos' Blue Origin to Launch 'High-Altitude Escape Motor Test' Wednesday
- NASA's James Webb Space Telescope: Hubble's Cosmic Successor
- Dwarf Planet Ceres' Bizarre Bright Spots Shine in Stunning Up-Close View
This article originally published at Space.com here | <urn:uuid:ec83373a-0938-46f8-9b6a-2497fc37cb05> | 3.9375 | 814 | Truncated | Science & Tech. | 38.426503 | 95,643,582 |
The strong southwesterly wind shear that has been battering Tropical Storm Ana has abated and has given the storm a chance to re-organize.
Ana appeared more rounded on imagery from NASA's Terra satellite as thunderstorms again circled the low-level center.
NASA's Terra satellite passed over Ana on Oct. 22 at 22:10 UTC (6:10 p.m. EDT). The MODIS instrument aboard Terra captured a visible image of the storm that showed clouds and showers were no longer being blown northeast of the center from southwesterly wind shear, as they had in the last couple of days.
The wind shear has weakened, which allowing for the showers and thunderstorms to redevelop around the center of the storm.
On Oct. 24, Ana was strengthening and moving northwest while crossing the northwest Hawaiian Islands east of Maro Reef.
A Tropical Storm Warning is in effect for portions of the Papahanaumokuakea Marine National Monument, from French Frigate Shoals to Lisianski.
At 8 a.m. (2 a.m. HST/1200 UTC) the center of Tropical Storm Ana was located near latitude 26.0 north and longitude 168.6 west. Ana was moving toward the northwest near 12 mph (19 kph) and this motion is expected to become more northerly through early Friday, then northeasterly through early Saturday, Oct. 25. Maximum sustained winds were near 50 mph (80 kph).
NOAA's Central Pacific Hurricane Center expects Ana to continue strengthening through early Saturday.
NASA's Goddard Space Flight Center
Rob Gutro | Eurek Alert!
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
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences | <urn:uuid:7c711e89-e209-4c80-bc60-4703960f7834> | 2.71875 | 972 | Content Listing | Science & Tech. | 49.53152 | 95,643,599 |
When Japanese researchers wanted to see if chimps could learn things from simply viewing a situation just once, they needed to create situations where apes would anticipate a noteworthy event. So they made their own horror films just for apes.
The plots of King Kong Attack and Revenge of King Kong were rudimentary. There was only one set — a room with two doors, a couple of researchers form Kyoto University, and a few scattered objects. In King Kong Attack, one of the doors opened and a man in an ape suit came barreling through. He made a few threatening motions before the film ended. In Revenge of King Kong, one of the researchers in the room fought back against King Kong, using a specific object.
It probably would have rated very low on the Rotten Tomato Meter if its sole audience weren't chimpanzees and bonobos. The chimps watched the film while they were being monitored by eye-tracking software.
A day later, the chimps watched the film again. Clearly it had some kind of impact. While rewatching King Kong Attack, the chimps steadily looked at the door through which King Kong had entered, and ignored the door through which they didn't expect an attacker. When they watched Revenge of King Kong, they focused on the object that the researcher had used to do battle with the rampaging ape, even if the object was in a different place on the screen.
The researchers write that these results show that, "great apes, just by watching the events once, encoded particular information (location and content) into long-term memory and later retrieved that information at a particular time in anticipation of the impending events."
The apes, meanwhile, look forward to the DVD release, and have commented positively on the films' reliance on practical effects rather than that "CGI crap." | <urn:uuid:708d300e-285c-4503-810d-e07c79594c66> | 2.84375 | 364 | News Article | Science & Tech. | 47.831978 | 95,643,618 |
Several species of pines (Pinus spp.; Pinaceae) are highly invasive in parts of the Southern Hemisphere, where pines are widely planted in commercial forestry plantations. Problems associated with the spread of pines from plantations have increased substantially over the past few decades. We review the current extent of the problem and the research that has been undertaken to explain different facets of these invasions, including the factors contributing to species invasiveness and the susceptibility of ecosystems to invasion. Recent interest in producing transgenic pines for wood production raises important issues when considering future scenarios for pine invasions and for sustainable commercial forestry. This chapter considers the genetic diversity in introduced versus native pine populations and then examines the potential for transgene escape from pine plantations in the Southern Hemisphere. Propagule pressure appears to play a major role in these invasions. Commercial plantations have typically introduced a large share of the species’ existing genetic diversity, resulting in rapid adaptation to local conditions and favoring the spread of feral pine populations. The extent to which inherent invasiveness of transgenic pines will differ from non-transgenic pines will depend on the properties conferred by the transgenes, but differences could be substantial. Even subtle changes in species-environment interactions could affect the dynamics of pine invasions. Genetic engineering for reproductive sterility could potentially reduce invasiveness, but criteria for forest certification current prohibit the use of any genetically-modified planting, thus blocking a potentially useful avenue of intervention. Integrated programs for managing pine invasions in the Southern Hemisphere will need to give serious attention to transgenic plantation forestry.
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Choose a citation style from the tabs below | <urn:uuid:6e07d614-1361-4b06-a59c-5ea544f87f65> | 3.09375 | 339 | Academic Writing | Science & Tech. | 0.99754 | 95,643,619 |
By this point you will have used and modified many of the example programs described earlier, and you will have written programs of your own. The problem of what to do when your program does not behave as expected is now relevant. Problems with programs are known as “bugs”, and the process of removing bugs from programs is known as “debugging”. We believe that a convenient approach to programming is what could be described as “preventative programming”. To paraphrase an old proverb, an ounce of careful programming is worth a pound of debugging. In this chapter we shall attempt to describe some techniques for debugging, but we shall start with a discussion of how to try to prevent bugs from infesting your programs. We realise that such a problem is unsolved in general, but we simply wish to convey some informal techniques that have helped other Prolog programmers.
KeywordsCurrent Goal Trace Model Prolog Program Prolog System Blank Line
Unable to display preview. Download preview PDF. | <urn:uuid:5928126e-4c73-4c51-85c8-eac13cf4f76e> | 3.859375 | 204 | Truncated | Software Dev. | 48.764848 | 95,643,629 |
This photo-like image was acquired by the Moderate Resolution Imaging Spectroradiometer modis.gsfc.nasa.gov/ (MODIS) on NASA's terra.nasa.gov/ Terra satellite on September 19, 2006, at 10:15 a.m. local time (14:15 UTC). Helene is a well-defined, sprawling storm system with long spiral arms, a tightly wound central portion, and a distinct eyewall of clouds encircling a cloud-filled eye. These are all telltale signs of a powerful hurricane. According to the University of Hawaii's http://www.solar.ifa.hawaii.edu/Tropical/tropical.html Tropical Storm Information Center, Helene had sustained winds reaching as high as 185 kilometers per hour (115 miles per hour), making it a powerful Category 3 storm. As of September 19, Helene was predicted to build power slightly since it was traveling over warm seas with no significant land to disrupt it.
NASA image created by Jesse Allen, Earth Observatory, using data provided courtesy of the rapidfire.sci.gsfc.nasa.gov/ MODIS Rapid Response team. | <urn:uuid:43e6adc0-9292-41fa-a8b2-9c274a7ef390> | 3.109375 | 241 | Knowledge Article | Science & Tech. | 56.272742 | 95,643,643 |
CESA-2009:1335 -- centos 5 x86_64 openssl
|ID: oval:org.secpod.oval:def:201982||Date: (C)2012-01-31 (M)2018-05-10|
|Class: PATCH||Family: unix|
OpenSSL is a toolkit that implements the Secure Sockets Layer and Transport Layer Security protocols, as well as a full-strength general purpose cryptography library. Datagram TLS is a protocol based on TLS that is capable of securing datagram transport . Multiple denial of service flaws were discovered in OpenSSL"s DTLS implementation. A remote attacker could use these flaws to cause a DTLS server to use excessive amounts of memory, or crash on an invalid memory access or NULL pointer dereference. Note: These flaws only affect applications that use DTLS. Red Hat does not ship any DTLS client or server applications in Red Hat Enterprise Linux. An input validation flaw was found in the handling of the BMPString and UniversalString ASN1 string types in OpenSSL"s ASN1_STRING_print_ex function. An attacker could use this flaw to create a specially-crafted X.509 certificate that could cause applications using the affected function to crash when printing certificate contents. Note: The affected function is rarely used. No application shipped with Red Hat Enterprise Linux calls this function, for example. These updated packages also fix the following bugs: * "openssl smime -verify -in" verifies the signature of the input file and the "-verify" switch expects a signed or encrypted input file. Previously, running openssl on an S/MIME file that was not encrypted or signed caused openssl to segfault. With this update, the input file is now checked for a signature or encryption. Consequently, openssl now returns an error and quits when attempting to verify an unencrypted or unsigned S/MIME file. * when generating RSA keys, pairwise tests were called even in non-FIPS mode. This prevented small keys from being generated. With this update, generating keys in non-FIPS mode no longer calls the pairwise tests and keys as small as 32-bits can be generated in this mode. Note: In FIPS mode, pairwise tests are still called and keys generated in this mode must still be 1024-bits or larger. As well, these updated packages add the following enhancements: * both the libcrypto and libssl shared libraries, which are part of the OpenSSL FIPS module, are now checked for integrity on initialization of FIPS mode. * an issuing Certificate Authority allows multiple certificate templates to inherit the CA"s Common Name . Because this CN is used as a unique identifier, each template had to have its own Certificate Revocation List . With this update, multiple CRLs with the same subject name can now be stored in a X509_STORE structure, with their signature field being used to distinguish between them. * the fipscheck library is no longer needed for rebuilding the openssl source RPM. OpenSSL users should upgrade to these updated packages, which resolve these issues and add these enhancements. | <urn:uuid:483146fa-5663-4220-8eba-1432e8c96f09> | 2.515625 | 653 | Documentation | Software Dev. | 43.471572 | 95,643,659 |
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Algal bloom: growth of marine algae that is so great, the algae changes the color of the water.
Host: an organism that is carrying a parasite.
In the marine biome, food is generally hard to come by. This is because most plants (which stay in one place and produce food regularly) cannot grow in the ocean. Much of the food in the marine biome comes instead from marine algae and phytoplankton. These tiny organisms can float around and spread to areas that have lots of sunlight and nutrients.
There are a lot of small fish and other predators out there eating the algae they filter out of the water. But what if you can't move to chase algal blooms around? Animals like coral that stay in one place have some more creative solutions to get enough food.
Corals survive using symbiosis. This is when two different organisms work together so that each species survives. Corals have a special relationship with algae. Instead of chasing after their food, corals keep algae inside their body. Coral skin is see-through so the algae inside can still turn sunlight into food. The algae share some of this food with the coral in exchange for a safe place to live. Sea fleas can't eat the algae if it is safe inside its coral castle.
But what happens when the water is too deep and dark for an algae cell to photosynthesize? You might think symbiosis would be impossible in the deep open ocean biome, and for algae to be involved, it is impossible. But other symbiotic relationships exist in some of the deepest habitats in the ocean: hydrothermal vents and cold seeps. These habitats couldn’t get further from what we usually think of as beneficial for life: they have never seen sunlight, the water is filled with poisonous chemicals, and water temperatures at vents are over 100°C (hotter than boiling water).
But the biggest difference between symbiosis in the shallow coastal biome and the deep ocean is that the producers don’t use sunlight to make food. Instead, the crabs, mussels, and worms near these vents and seeps eat special bacteria or hold it in their skin.
The bacteria can turn chemicals like hydrogen sulfide and methane into food. This way of producing food is called chemosynthesis because the bacteria make food from chemicals, not light.
These bacteria provide food to their hosts, allowing the invertebrate host to live and thrive in places no other animals could. Of course where you find worms and clams, you find predators. These ecosystems are home to all sorts of familiar life: crabs, sea slugs, octopus, and even fish.
There have been over 300 species found in these deep-sea habitats that haven’t been found anywhere else on Earth. In fact, the organisms that live in hydrothermal vents on opposite sides of the planet are more related to each other than their cousins at the surface.
These special bacteria are the basis of a whole ecosystem (one of the few we know about) that exists without needing light. These habitats are so unique they could possibly be considered their own biome.
However, bacteria that get food from chemicals don’t only live in the deep ocean. After scientists found the first hydrothermal vents in the 1970’s, they started looking for bacteria that chemosynthesize in other biomes – and they found them! Just think: we had to go to the very bottom of the ocean to learn about species that live around us every day.
Additional images via Wikimedia Commons. Tube worms by Charles Fisher.
Dr. Biology. (2014, November 19). Producers of the Open Ocean. ASU - Ask A Biologist. Retrieved July 18, 2018 from https://askabiologist.asu.edu/producers-open-ocean
Dr. Biology. "Producers of the Open Ocean". ASU - Ask A Biologist. 19 November, 2014. https://askabiologist.asu.edu/producers-open-ocean
Dr. Biology. "Producers of the Open Ocean". ASU - Ask A Biologist. 19 Nov 2014. ASU - Ask A Biologist, Web. 18 Jul 2018. https://askabiologist.asu.edu/producers-open-ocean
Many tube worm species live deep in the ocean. Some are important members of the ecosystems found near hydrothermal vents. | <urn:uuid:f4da816b-74f4-4f34-8dd2-8f2b30eb75e3> | 3.796875 | 934 | Knowledge Article | Science & Tech. | 57.455059 | 95,643,669 |
Heat has always been a problem for fuel cells. There’s usually either too much (ceramic fuel cells) for certain portable uses, such as automobiles or electronics, or too little (polymer fuel cells) to be efficient.
Image: Ddiagram of a fuel cell’s polymer electrolyte membrane (PEM) with the proton-conducting group triazole (the circles in the diagram). Protons hop from one group to another to move through the PEM without the need of water.
While polymer electrolyte membrane (PEM) fuel cells are widely considered the most promising fuel cells for portable use, their low operating temperature and consequent low efficiency have blocked their jump from promising technology to practical technology.
But researchers at the Georgia Institute of Technology have pinpointed a chemical that could allow PEM fuel cells to operate at a much higher temperature without moisture, potentially meaning that polymer fuel cells could be made much more cheaply than ever before and finally run at temperatures high enough to make them practical for use in cars and small electronics.
A team lead by Dr. Meilin Liu, a professor in the School of Materials Science and Engineering at Georgia Tech, has discovered that a chemical called triazole is significantly more effective than similar chemicals researchers have explored to increase conductivity and reduce moisture dependence in polymer membranes. The findings were published in the Journal of the American Chemical Society.
“Triazole will greatly reduce many of the problems that have prevented polymer fuel cells from making their way into things like cars, cell phones and laptops,” said Liu. “It’s going to have a dramatic effect.”
A fuel cell essentially produces electricity by converting the chemicals hydrogen and oxygen into water. To do this, the fuel cell needs a proton exchange membrane, a specially treated material that looks a lot like plastic wrap, to conduct protons (positively charged ions) but block electrons. This membrane is the key to building a better fuel cell.
Current PEMs used in fuel cells have several problems that prevent them from wide use. First, their operating temperature is so low that even trace amounts of carbon monoxide in hydrogen fuel will poison the fuel cell’s platinum catalyst. To avoid this contamination, the hydrogen fuel must go through a very expensive purification process that makes fuel cells a pricey alternative to conventional batteries or gasoline-fueled engines. At higher temperatures, like those allowed by a membrane containing triazole, the fuel cell can tolerate much higher levels of carbon monoxide in the hydrogen fuel.
The use of triazole also solves one of the most persistent problems of fuel cells — heat. Ceramic fuel cells currently on the market run at a very high temperature (about 800 degrees Celsius) and are too hot for most portable applications such as small electronics.
While existing PEM fuel cells can operate at much lower temperatures, they are much less efficient than ceramic fuel cells. Polymer fuel cell membranes must be kept relatively cool so that membranes can retain the moisture they need to conduct protons. To do this, polymer fuel cells were previously forced to operate at temperatures below 100 degrees Celsius.
Heat must be removed from the fuel cells to keep them cool, and a water balance has to be maintained to ensure the required hydration of the PEMs. This increases the complexity of the fuel cell system and significantly reduces its overall efficiency. But by using triazole-containing PEMs, Liu’s team has been able to increase their PEM fuel cell operating temperatures to above 120 degrees Celsius, eliminating the need for a water management system and dramatically simplifying the cooling system.
“We’re using the triazole to replace water,” Liu said. “By doing so, we can bring up the temperature significantly.”
Triazole is also a very stable chemical and fosters stable fuel cell operating conditions.
While they have pushed their polymer fuel cells to 120 degrees Celsius with triazole, Liu’s team is looking into better polymers to get those temperatures even higher, he said.
Source: Georgia Institute of Technology
Explore further: Engineers design new solid polymer electrolyte, paving way for safer, smaller batteries and fuel cells | <urn:uuid:be2dc11a-e75f-4024-96ee-0a2b0cf03143> | 4.1875 | 869 | News Article | Science & Tech. | 28.812658 | 95,643,689 |
Classifying corals in terms of species is a risky business. Biologist Onno Diekmann from the University of Groningen has discovered that four species of stone corals differ so little in terms of their genetic material that they can scarcely be termed separate species.
Corals are formed by a collection of identical coral polyps which together form a coral colony. Onno Diekmann compared the genetic material from six different species of coral from the Madracis genus, which are found in the coral reefs around Curaçao. The coral exists in many different physical forms. There are knobby, branched and crust-forming colonies. The corals grow at depths varying from 2 to 70 metres. The external appearance is partly determined by the environmental conditions, such as temperature, water movements and the amount of available light. Therefore, it is difficult to determine if two coral colonies belong to the same species, if only the external appearance is used.
Two forms of Madracis were found to be clearly distinct species. Yet four other species exhibited a considerable overlap in the genetic variation. Therefore, which of the four species these corals belong to cannot be determined with any certainty. The spectrum of intermediate forms indicates that these four species can interbreed. However, the four species do differ in their physical appearance. In addition to the colony form there are also smaller characteristics where differences might be exhibited. Yet none of the individual microcharacteristics can be used to unequivocally determine which species an individual coral belongs to. For this several characteristics need to be analysed at the same time.
Nalinie Moerlie | EurekAlert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences | <urn:uuid:fa337f51-7b8b-4294-84c5-e0d8cacdef52> | 3.765625 | 973 | Content Listing | Science & Tech. | 36.000793 | 95,643,706 |
- Open Access
Evolving a photosynthetic organelle
© Nakayama and Archibald; licensee BioMed Central Ltd. 2012
Received: 4 April 2012
Accepted: 23 April 2012
Published: 24 April 2012
The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles.
The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis - the conversion of solar energy into chemical energy - and in so doing had a huge impact on the course of evolution and the climate of Earth . From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore [2, 3] and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle . The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.
Plastids evolved once, a long time ago
Photosynthetic eukaryotes are a tremendously diverse collection of organisms, from bacterium-sized unicells and giant kelp in the oceans to the plants and trees that inhabit dry land. Multiple rounds of eukaryote-eukaryote endosymbioses have resulted in a tangled web of plastid-bearing lineages . Yet despite this complexity, all plastids appear to trace back to a single ancient endosymbiotic event between cyanobacteria and a heterotrophic host eukaryote. This so-called primary endosymbiosis probably occurred over one billion years ago . The primary plastids of land plants, green algae, red algae and glaucophytes differ tremendously from their presumed cyanobacterial progenitors. What we know for certain is that the majority of the genes present in the endosymbiont were lost or transferred to the host nuclear genome and the protein products of many of these genes are now reimported into plastids by a sophisticated import apparatus (the TIC-TOC complex; translocon complex of the inner and outer chloroplast membranes ). Unfortunately, much of the molecular and cellular evolution that accompanied the transition from cyanobacterium to photosynthetic organelle is unclear. A variety of intra- and extra-cellular cyanobacterial symbionts are found in present-day eukaryotes , but the details of their host-symbiont relationships rarely tell us anything meaningful about the evolution of plastids. Paulinella chromatophora appears to be a remarkable exception.
Paulinellaas a window on organellogenesis
A recent flurry of activity on Paulinella was sparked by the work of Marin et al. . Working with a highly prized stable culture of Paulinella chromatophora, these authors reported the ribosomal DNA (rDNA) sequence of the chromatophore, phylogenetic analysis of which clearly showed that it originated from a member of the cyanobacterial Synechococcus/Prochlorococcus clade. The chromatophore rDNA sequences show no affinity to those of plastids, indicating that its organelle-like characteristics evolved independently of known plastids and thus could represent another primary endosymbiosis.
To what extent is the chromatophore integrated with the host cell? Key insight has come from the complete chromatophore genome sequences of two Paulinella strains [2, 3]. Both genomes are approximately 1 megabase pairs (Mbp) in size and contain approximately 850 protein-coding genes. This is significantly reduced compared to the genome of its closest known free-living relative, the cyanobacterium Synechococcus WH5701, which is approximately 3 Mbp in size and has 3,346 protein-coding genes. Interestingly, numerous genes essential for cyanobacterial growth have disappeared from the chromatophore genome, including a complete set of genes for the energy-generating tricarboxylic acid cycle, as well as biosynthetic pathways for five amino acids and several cofactors. This explains why the Paulinella chromatophore is unable to grow on its own and suggests a significant level of integration with its host, at least at a metabolic level.
Gene transfer: a necessary but not sufficient step in organellogenesis
The extent and pattern of genome reduction and loss of essential genes in the Paulinella chromatophore are very different from that seen in plastids. Plastid genomes are typically <0.2 Mbp in size and most photosynthesis-related genes reside in the nuclear genome of plastid-bearing organisms . In contrast, core genes for photosynthetic activity (which is clearly the main function of the chromatophore) still reside on the chromatophore genome [2, 3]. Nonetheless, the degree of genome reduction/gene loss exhibited by chromatophores is roughly comparable to that seen, for example, in the Buchnera endosymbionts of aphids, which are not considered organelles (for example, ). Therefore, in and of itself, genomic data cannot answer the question of whether the chromatophore is a photosynthetic organelle or not. There has been much debate on the topic [14–16]. It is generally agreed that the existence of a mechanism for the import of host nucleus-encoded proteins is a necessary condition for a subcellular entity of endosymbiotic origin to be considered a true organelle [14, 17]. Does such a mechanism exist in Paulinella? How much endosymbiotic gene transfer (EGT) has actually taken place?
The answer to the second question has come from analyses of expressed genes in the Paulinella nuclear genome. A total of 33 chromatophore-derived nuclear genes have been detected in two Paulinella species thus far; in terms of G+C content, these genes are more like nuclear genes than chromatophore genes, and at least some of them have spliceosomal introns (a hallmark of nuclear genes) [2, 3, 18, 19]. Clearly these genes have resided in the host nuclear genome for some time. Interestingly, the products of the majority of these EGT-derived genes are related to photosynthesis, including components of the Photosystem I (PSI) reaction center PsaE, PsaI, and PsaK, strongly suggesting that they function in the chromatophore. But how do they get there? Protein import into canonical plastids is typically mediated by the presence of amino-terminal extensions, referred to as transit peptides, on plastid protein precursors , but the deduced amino termini of the Paulinella proteins were not obviously longer than their counterparts in cyanobacteria .
Protein import: the last piece of the puzzle
Using biochemical means, Nowack and Grossman have convincingly demonstrated that at least some of the nucleus-encoded, chromatophore-derived proteins in Paulinella function in the chromatophore. Specifically, the authors carried out western blot analysis and amino-terminal sequencing to confirm that the product of the nuclear psaE gene and two distinct PsaK proteins are assembled into chromatophore-derived PSI. Further, inhibition experiments targeted at cytosolic- and chromatophore-derived ribosomes indicate that the PsaE and PsaK proteins are synthesized by the host's 80S ribosomes. Immunogold electron microscopy using a PsaE-specific antibody revealed a clear accumulation of gold particles on the chromatophore thylakoid membranes, suggesting the existence of a selective protein import system. Even more interesting is the fact that gold particles were also seen decorating the Golgi apparatus of the host, in addition to the chromatophore itself. This result is consistent with the intriguing possibility that the PsaE protein of Paulinella is targeted to the chromatophore by an endoplasmic reticulum-Golgi-based system. The host cell secretion system has on multiple occasions been co-opted to function in the targeting of plastid proteins in organisms with secondary plastids (for example, dinoflagellates, euglenophytes and heterokontophytes [1, 20]), and also appears to be used to target a minority of proteins to primary plastids . The 'recycling' of pre-existing protein trafficking machinery is thus an emerging theme in the evolution of photosynthetic organelles.
The work of Nowack and Grossman effectively puts to rest doubts over whether the chromatophore of Paulinella is an organelle. Yet there is still much to learn. Despite the clear localization of EGT-derived proteins to the Paulinella chromatophore, the exact nature of the targeting pathway is still far from clear. Considering currently available bioinformatic, transcriptomic, and amino-terminal protein sequence data, there is no consistent picture as to whether nucleus-encoded, chromatophore-localized proteins such as PsaE and PsaK have amino-terminal extensions that could mediate their transport [4, 18], although the presence of signal peptide-like sequences has been proposed . In the case of PsaE at least, transport presumably requires other protein factors and elucidating these factors will be an important next step. Although the PsaE protein of Paulinella was shown to pass through the Golgi, the possibility that PsaK and other endosymbiotically derived proteins are targeted to the chromatophore in a Golgi-independent manner cannot be ruled out. Considering the extent of genome reduction and the apparent paucity of transferred genes in the Paulinella nuclear genome compared to organisms with canonical plastids, the current state of the chromatophore should be regarded as an early step in organelle evolution. It will thus perhaps not be surprising if its protein import system turns out not to be highly tuned. Ultimately, the extent to which the Paulinella chromatophore can shed light on the evolution of canonical plastids will depend on the similarities and differences inferred about their independent evolutionary trajectories.
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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. | <urn:uuid:fb6248cd-70e0-493e-81cd-6d2fdaf8086f> | 3.375 | 3,744 | Academic Writing | Science & Tech. | 35.716184 | 95,643,715 |
The Nordic Orion became the first cargo ship to take the treacherous Northwest Passage from the Pacific Ocean to Europe last year, and now its Danish operators are planning more trips across the Arctic as the sea ice melts.
If no new policy measures are adopted to combat global warming, the cost of climate change in Europe could reach almost 4 % of the gross domestic product (GDP) of the European Union by the end of the century.
The big freeze in the US was part of an Arctic weather system that is being displaced more and more frequently because of global warming, European researchers believe. As it re-centres itself over the pole, it should bring colder, icier conditions back to Europe.
From Europe and Asia, 14 countries – encompassing a total of 26 institutions – have come together to set up an Arctic observatory that will combine data from the sea, the atmosphere and the ground to provide vital evidence about the rate of climate change.
Dr Marc von Hobe, from the German Forschungszentrum Jülich GmbH research centre, is coordinator of the EU-funded RECONCILE project. The project contributed to the first detection in 2011 of a hole in the ozone layer over the Arctic. Dr von Hobe believes more work needs to be done to control greenhouse gas emissions.
Complex and painful disease has been historically overlooked, researchers say.
Robin Garrity says that registration, identification and geofencing will increase security.
Chemical switches on DNA could explain how the environment may influence the traits we pass on, according to Prof. Thomas Carell. | <urn:uuid:9eead4fe-9b84-4443-9c67-867a5fa33dcc> | 3.515625 | 325 | Content Listing | Science & Tech. | 38.896681 | 95,643,717 |
It isn’t easy to spot planets far away in our galaxy – normally we can only infer their presence, from the effect they have on their host stars. But now a group of astronomers has demonstrated an easier way to study distant worlds, by detecting the first visible light reflected off an exoplanet.
The Philae probe landing on comet 67P/Churyumov–Gerasimenko on 12 November was awe-inspiring, but the main science phase of Rosetta is yet to come, said Dr Colin Snodgrass, the coordinator of the mission’s ground-based observation campaign and lead scientist on the EU-funded ISANDAL project, speaking from the European Southern Observatory in Chile.
The Large Hadron Collider (LHC), the world’s biggest particle smasher, will look for known unknowns such as dark matter, but also for so-called unknown unknowns that researchers have little idea about. That is according to Professor Fabiola Gianotti, the newly appointed Director-General of CERN, the European Organization for Nuclear Research, which helped identify the Higgs boson.
The planned Square Kilometre Array telescope, a radio telescope to span two continents, could be instrumental in finding intelligent alien civilisations within our lifetimes, according to Dr Seth Shostak, senior astronomer at the US-based Search for Extra Terrestrial Intelligence (SETI) Institute. Dr Shostak was a speaker at the EU's Innovation Convention in March 2014.
Complex and painful disease has been historically overlooked, researchers say.
Robin Garrity says that registration, identification and geofencing will increase security.
Chemical switches on DNA could explain how the environment may influence the traits we pass on, according to Prof. Thomas Carell. | <urn:uuid:cef774bc-efc6-4a1b-864a-fb4ae4141068> | 3.234375 | 363 | Content Listing | Science & Tech. | 29.79144 | 95,643,718 |
Darkness will fall over a huge swath of America on August 21.
The good news is that the solar eclipse will be visible from more than ten states. The bad news, however, is you’ll have to cross your fingers you happen to live on the path, because hotels and campsites are booked solid.Prince Louis looks just like Prince George in new picture released by Kate and Wills
Accommodation got booked up faster than Coachella when the eclipse date dropped last year.
The show will take place over parts of Idaho, Montana, Wyoming, Nebraska, Missouri, Kentucky, Tennessee, Kansas, Georgia, North Carolina and Iowa.
The path is pretty narrow — around 60 to 70 miles. NASA created this handy map:
When and where can I see the eclipse?
As the moon moves in front of the sun, daylight will yield to darkness from Oregon to South Carolina along a path 60 to 70 miles wide.
The path of totality will also cut across broad swaths of Idaho, Montana, Wyoming, Nebraska, Missouri, Kentucky and Tennessee, along with corners of Kansas, Georgia and North Carolina, and a tiny chip of Iowa.
Totality will first hit Oregon around 10.15am Pacific time. South Carolina will experience the final moments of total darkness at 2.49pm Eastern time.
Lika Guhathakurta, an astrophysicist at NASA Headquarters in Washington, said: ‘An eclipse teaches us so many things, but the 2017 eclipse is especially unique because of the uninterrupted land masses it will pass over.
‘This will allow us to maximize our chance to collect data and connect the shadow of the moon to Earth science.’
The solar eclipse explained by NASA
Solar eclipses occur when the moon blocks any part of the sun. Total solar eclipses, however, are only possible on Earth because of a cosmic quirk of geometry: The sun’s diameter is 400 times wider than the moon’s, but it is also 400 times farther away.
The result is that the sun and the moon appear to be the same size from our perspective. When they line up just right, the moon can obscure the sun’s entire surface, creating a total solar eclipse.
This line-up occurs once every 12 to 18 months. Partial solar eclipses, on the other hand, occur when the alignment is such that the moon blocks only part of the sun, and these can occur more frequently. | <urn:uuid:44d94f06-9171-4894-be5a-e69a2b351720> | 2.671875 | 508 | News Article | Science & Tech. | 52.408384 | 95,643,761 |
This chapter develops the standard properties of topological spaces. Most of these properties do not go beyond the level of a convenient language. In the text proper, we have given precisely those results which are used very frequently in all analysis. In the exercises, we give additional results, of which some just give routine practice and others give more special results. To incorporate all this material in the text proper would be extremely oppressive and would obscure the principal lines of thought inherent in the basic aspects of the subject. The reader can always be referred to Bourbaki [Bo] or Kelley [Ke] for encyclopaedic treatments.
KeywordsTopological Space Compact Space Open Ball Open Covering Weak Topology
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Pennsylvania bats: Some species headed for extinction?
Pennsylvania's bats have not come back.
After being decimated by white-nose syndrome, cave bats, especially the little brown bat and the northern long-eared bat, continue to show signs of massive decline, experts say.
This is the time of year when the Pennsylvania Game Commission conducts its annual survey of cave bats, which hibernate underground from October through mid-April.
The hibernacula surveys, as they're called, have revealed that while some threatened bat species are surviving and adapting, most of the devastated populations have not recovered.
Winter surveys have shown a mortality rate of 99 percent, while summer roost counts show a decline of 93 percent, said Tammy Colt, Southwest Region diversity biologist with the game commission.
“It could lead to the extinction of some species,” she said. “We lost so many in such a short time span, it would be nearly impossible for them to grow their numbers back up.”
Unlike some mammals, bats do not reproduce in large numbers — females have only one pup per year, Colt said. Juveniles often lead a tenuous existence until they get through their first winter.
Pennsylvania is home to six species of hibernating bats and four species of migratory bats.
White-nose syndrome, a fungus that affects bats while they're hibernating, was first detected in a single cave in New York in 2007. It was discovered in Pennsylvania in the winter of 2008-09 in a half dozen sites in Lackawanna, Luzerne and Mifflin counties, said Greg Turner, superintendent of the game commission's Endangered and Nongame Mammal Section.
The syndrome had spread statewide by 2012 , including Westmoreland County in 2010-11 and Fayette County in 2009-10. Sites with 30,000 bats dropped to the single digits within 90 days, he said.
“Overall, our cave bat population decline is 98.9 percent. It's maintaining at that level,” said Turner, whose survey activities took him to Somerset County on Monday.
Bats infected by white-nose syndrome are unable to hibernate properly, causing them to burn up their winter fat stores and starve to death, Turner said. A white fungus grows on the noses of some infected bats.
The Austin-based nonprofit Bat Conservation International has called the population decline from white-nose syndrome “the most precipitous wildlife collapse of the past century” and Pennsylvania the hardest-hit state.
However, Turner sees a faint glimmer of hope, which he documented in the 2016 book, “Conservation and Ecology of Pennsylvania's Bats” (Pennsylvania Academy of Science).
Turner wrote a chapter showing how some survivors of white-nose syndrome are adapting by hibernating in colder places. The fungus does not thrive in climates where the temperature dips below 38 degrees; bats normally hibernate in temperatures between 44-49 degrees, he said.
“The only sites with a sizeable number of survivors were the ones that were really cold,” Turner said. “There's just a handful of these sites … where we started noticing these survivors. Those sites that are super cold are the only ones where we see bat numbers increasing. Most of the other sites we see are not doing well.”
Bats are using that cold temperature to slow the growth of the fungus and conserve energy, but Turner stops short of calling it a recovery.
“It looks mostly like we've stabilized,” he said.
Colt said there is evidence to suggest that white-nose syndrome is not 100 percent fatal.
“Some little brown bats got it and survived to the next winter and seemed to be OK,” she said. “We don't know if that's because of an immune response or some bacteria that's fighting the fungus.”
The decline in the bat population has serious implications for humans.
Because bats eat insects, bats can reduce everything from mosquito-borne diseases to agricultural pests. The average bat consumes 1,000 to 1,500 insects per night.
Stephen Huba is a Tribune-Review staff writer. Reach him at 724-850-1280, email@example.com or via Twitter @shuba_trib. | <urn:uuid:3785a84e-bb23-4585-a424-4f25a2abfd73> | 3.265625 | 903 | News Article | Science & Tech. | 47.014359 | 95,643,765 |
Collisional cooling of ions in the rf-only multipole guides has become a method of choice for coupling electrospray sources to various mass analyzers. Normally parameters of such ion guides (length, pressure) provide enough thermalization and focusing for ions in a wide mass range. Noncovalent complexes, however, have more compact conformations than denatured biomolecules of similar mass and, therefore may not be transmitted efficiently through standard ion guides, as demonstrated by theoretical analysis, simulations, and experiments. Several methods of improving collisional cooling for large compact ions have been developed on a quadrupole time-of-flight instrument, which include operating the ion guides at higher pressure and trapping ions to increase the cooling time. Improved transmission of heavy ions obtained with those methods is studied in experiments with proteasome 20S, an oligomeric protein noncovalent complex with molecular weight around 692,000, and a few other compounds.
Mendeley saves you time finding and organizing research
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Find the osmotic pressure of the solution: Lets understand how to find the osmotic pressure of a solution when you have given mass using osmotic pressure equation.
(A) Isotonic intervenous solutions contain 49 g/L of glucose .What is the osmotic pressure of blood?Solution A :
Strategy: Isotonic solutions by defination exert equal osmotic pressure.Therefore Π for the blood is same as Π for glucose solution.We can calculate Π from the osmotic pressure equation after converting the concentration into moles per liter.
Step 1: Find the number of moles of glucose :
Molar mass = 180 g/mol (from the formula of glucose C6H12O6) using the mass in grams of glucose given in the problem find the number of moles of glucose:-
Moles of glucose = mass in grams/molar mass
= 48 g/ 180 g/mol = 0.26 moles of glucose
Step 2: Find the molarity of the glucose solution:
Subsitute the number of moles of glucose from step 1 into molarity equation to find the molarity of glucose solution
M = 0.26 moles/ 1 L = 0.26 mol/L
Step 3 : Convert the temperature given in degree celcius to Kelvins:
Because we are working with blood in the human body,T is the human body temperature 37 degree celcius.And as temperature should be in Kelvins we do degree celcius to kelvin conversion:
T = 37 = 273 = 310 K , R= 0.082 L atm/mol K
Step 4: Finally find the osmotic pressure using Π = MRT equation:
Π = 0.272 mol/L * 0.082 l atm/mol K * 310 K
= 6.9 atm | <urn:uuid:765b2402-1a9d-4ce7-a19e-717b7dce37d3> | 3.0625 | 398 | Tutorial | Science & Tech. | 63.200305 | 95,643,771 |
As our oceans are suffering the devastating effects of human exploitation and climate change, various marine life are struggling ro survive.
Here are some of the most threatened ocean species, and ways in which we can contribute in working towards their conservation.
A huge portion of our planet's land mass is being used for agriculture, with a staggering 70% occupied for Livestock production.
Suprisingly, 18% of our Carbon emissions are caused by livestock activities, fuel intensive farming practices, and deforestation.
In the last 150 years, human activites have cause CO2 levels to skyrocket and our earth's entire climate to warm.
Global warming and Climate change affects each and every one of you; lets do our part in restoring balance to our environment! | <urn:uuid:1cc7e8d1-575c-4f07-bc9a-668abcc81130> | 2.8125 | 151 | About (Org.) | Science & Tech. | 32.350269 | 95,643,782 |
Three generations of small diameter ceramic fibres based on polycrystalline silicon carbide have been developed over a period of thirty years. This has been possible due to studies into the relationships between the microstructures and properties of the fibres. A variety of techniques have been employed by research teams on three continents. The fibres are made by the conversion of polymer precursors to ceramic fibres and all three generations are presently produced commercially. The nature of the precursor and the techniques used for cross-linking have been varied in order to optimise both properties and cost of manufacture. It has been possible to improve the characteristics of the fibres as the processes involved in the cross-linking of the precursor fibres have been better understood and the mechanisms governing both room temperature and high temperature behaviour determined. The result is that, although first generation fibres were limited by a low Young's modulus at room temperature and by creep and instability of the structure at temperatures far lower than those limiting the behaviour of bulk silicon carbide, the third generation fibres shows many of the characteristics of stoichiometric silicon carbide. This remarkable improvement in characteristics has been due to a thorough understanding of the materials science governing the behaviour of these fibres which are reinforcements for ceramic matrix composite materials.
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Scientists from St.Petersburg University and Zelinsky Institute, Russia investigated chemical applications of calcium carbide. The project advances the idea of diverse acetylene chemistry on the basis of carbide technology. Cheap carbide raw material has been transformed into valuable products for material science and organic synthesis.
Over the last few decades, researchers have focused their attention on very large molecules and molecular systems. Scientists from all over the world study proteomics, genomics, construct complex proteins, nucleic acids, decode the genomes of entire organisms, and design new sub-cellular structures.
Outstanding enthusiasm for these important and essential areas of science has become so widespread that the question arose: "Is there a place for small organic molecules in modern science?" It might seem that old and well-known small organic molecules, as well as some areas of classical organic chemistry, have been forgotten.
Remarkably, despite the above mentioned trend of mega-molecules, state-of-the-art research anticipates re-investigation of tiny molecules. Indeed, small molecules carry a huge and previously unrevealed potential for science and industry. Renaissance in this area of science initiated an enlightenment of the well-known small molecules. An example of a small molecule is acetylene and derivative of acetylene - CaC2 or calcium carbide.
Friedrich Wohler first introduced the prominent calcium carbide in 1862. As a matter of fact, this breakthrough revolutionized the lighting in the 20th century Europe and US. The manufacture of carbide reached thousands of tons by the middle of the last century. Such an increase was caused by the fact that carbide was mainly used for the production of acetylene. Nevertheless, the end of carbide lamps era came with the advent of safer electric light sources. The development of catalysis and petrochemistry introduced cheaper acetylene sources, so calcium carbide was left behind.
An innovative method, proposed by a group of researchers led by Professor Ananikov, investigates the synthesis of valuable organic molecules directly from calcium carbide, without separation and storage of acetylene gas. As an example, thiovinylation reaction occured directly in the reaction mixture. Firstly, acetylene is allocated from calcium carbide and water, and secondly, thiol molecules get attached to the acetylene molecules. Both processes take place one-pot and do not require sophisticated equipment. The use of calcium carbide not only fundamentally simplifies and reduces the cost of synthesis, but also avoids the problems associated with transporting, storing, and handling of acetylene gas.
The developed process gives a vivid example of successful replacement of dangerous and difficult to handle acetylene gas by a simple and inexpensive calcium carbide. If the further research manages to carry out the chemistry of acetylene utilizing carbide-based technologies, the proposed method will open a new direction in organic chemistry. Without a doubt, the "little" calcium carbide will find its a place in modern chemistry, which acknowledges the ideas of safety, sustainability, and simplification.
The article «Efficient Metal-Free Pathway to Vinyl Thioesters with Calcium Carbide as the Acetylene Source» by Konstantin Rodygin and Valentine P. Ananikov was published in Green Chemistry journal by the Royal Society of Chemistry.
Reference: Green Chemistry, 2015; DOI: 10.1039/C5GC01552A
On-line link: http://dx.doi.org/10.1039/C5GC01552A
Ananikov Laboratory | ResearchSea
Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern
20.07.2018 | Princeton University
Relax, just break it
20.07.2018 | DOE/Argonne National Laboratory
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.
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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....
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Bacteria speak to one another using peptide signals in a soundless language known as quorum sensing. In a step towards translating bacterial communications, researchers at Princeton University have revealed the structure and biosynthesis of streptide, a peptide involved in the quorum sensing system common to many streptococci.
"It's extremely rare for one research group to do both natural products discovery and mechanistic enzymology," said Leah Bushin, a member of the Seyedsayamdost lab and co-first author on the article published on April 20 in Nature Chemistry. Bushin worked on elucidating the structure of streptide as part of her undergraduate senior thesis project and will enter Princeton Chemistry's graduate program in the fall.
To explore how bacteria communicate, first she had to grow them, a challenging process in which oxygen had to be rigorously excluded. Next she isolated the streptide and analyzed it using two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy, a technique that allows scientists to deduce the connections between atoms in a molecule by pulsing their nuclei with powerful magnets to pulse atomic nuclei.
The experiments revealed that streptide contained an unprecedented crosslink between two unactivated carbons on lysine and tryptophan, constituting a new class of macrocyclic peptides. "We didn't think it would be as cool as a carbon-carbon bond between two amino acid side chains, so it was definitely a surprise." said Bushin.
To figure out how this novel bond was being formed, the researchers took a closer look at the gene cluster that produced streptide. Within the gene cluster, they suspected a radical S-adenosyl methionine (SAM) enzyme, which they dubbed StrB, could be responsible for this unusual modification.
"Radical SAM enzymes catalyze absolutely amazing chemistries," said Kelsey Schramma, a graduate student in the Seyedsayamdost lab and co-first author on the article. "There are over 48,000 radical SAM enzymes, but only about 50 have been characterized and just a dozen or so studied in detail," she said.
To probe the enzyme's role in making streptide, the researchers created a mutated version of the bacteria lacking the strB gene. The mutant failed to produce streptide, confirming that the StrB enzyme was significant and warranted further study.
Schramma determined that in order to function properly, the StrB enzyme required some key components: the pre-crosslinked substrate, which she prepared synthetically, cofactor SAM, reductant, and two iron-sulfur (Fe-S) clusters carefully assembled in the protein interior. The team then showed that one of the FeS clusters reductively activated one molecule of SAM, kicking off a chain of one-electron (radical) reactions that gave rise to the novel carbon-carbon bond.
"The synergy between Leah and Kelsey was great," said Mohammad Seyedsayamdost, an assistant professor of chemistry at Princeton who led the research team. "They expressed interest in complementary aspects of the project and the whole ended up being greater than the sum of its parts," he said.
Their efforts included not only chemical and biological approaches, but also theoretical computational studies. While the 2D NMR experiments revealed the flat structure of streptide, its three-dimensional conformation was still unknown.
"Since the crosslink had never been reported, we had to code the modification into the program, which took a bit of creativity," Bushin said. After corresponding with the software creator, they were able to confidently assign a key residue in the macrocycle with the S-configuration.
Future work will target streptide's biological function -- its meaning in the bacterial language -- as well as confirming its production by other streptococcal bacteria strains.
"What we have revealed is a new and unusual mechanism that nature uses to synthesize macrocyclic peptides. There is a lot of novel chemistry to be discovered by interrogating bacterial secondary metabolite biosynthetic pathways," Seyedsayamdost said.
Read the full article here:
Schramma, K. R.; Bushin, L. B.; Seyedsayamdost, M. R. "Structure and biosynthesis of a macrocyclic peptide containing an unprecedented lysine-to-tryptophan crosslink." Nature Chemistry, 2015, 7, 431.
This work was supported by the National Institutes of Health (grant no. GM098299), and by Princeton University start-up funds.
Tien Nguyen | EurekAlert!
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
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03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
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Every time energy changes forms, some portion is "lost." With each change some amount of the original energy turns into heat.
LED lighting offers greater energy efficiency, longer lamp life, and exceptional control over the color and hue of emitted light compared to older lighting technology. Learn more.
An increasing share of future needs will be met by technologies now in the research or development stage.
Many of the world’s poorest people, who lack the resources to respond to the impacts of climate change, are likely to suffer the most.
Explore the usages of primary energy sources throughout the United States.
Today's best-performing all-electric vehicles can travel up to 300 miles emissions-free on a single battery charge.
The future of American society and its unprecedented standard of living depend, to a large degree, on how we use energy. The energy choices we make shape not only our quality of life, but the health of the environment, how we work and play, the strength of our economy, and our national security. Sound decisions by individuals, communities, and the nation depend on trustworthy and objective energy information. To help fill that need, the National Academies of Sciences, Engineering, and Medicine provide this energy primer.
Discover how the strength of American industry, speed of transportation, and countless modern conveniences all come from our ingenious use of energy.
The United States depends on a variety of energy sources. What advantages and challenges does each one present to our nation and its people?
Learn about the costs of our high standard of living—to the environment, to our national security, and to irreplaceable resources.
- Chlorofluorocarbon Refrigerant Fluid (CFC)
A compound of carbon, chlorine, and fluorine (and possibly hydrogen) used as a refrigerant fluid. CFCs originally replaced more toxic and reactive chemicals, but are now being phased out as refrigerants because of their ozone-depleting properties in the upper atmosphere.
- America’s Energy Future: Technology and Transformation (2009)
- Real Prospects for Energy Efficiency in the United States (2010)
- Electricity from Renewable Resources: Status, Prospects, and Impediments (2010)
- Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts (2009) | <urn:uuid:134c3b33-0a76-4dd6-83f9-5b84def7123a> | 3.203125 | 482 | Content Listing | Science & Tech. | 26.265 | 95,643,856 |
a) how many km^2 of forest does the image represent?
b) how many km^2 of the forest is burned?
c) how many km^2 of forest remained after the fires?
I know that 1 pixel = 900m^2 but I do not know how to solve these problems.
No one has answered this question yet.
Recently Asked Questions
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Collection of small subunit (16S- and 16S-like) ribosomal RNA structures: 1994.
- Published Article
Nucleic acids research
- Publication Date
Sep 01, 1994
A collection of diverse 16S and 16S-like rRNA secondary structure diagrams are available. This set of rRNAs contains representative structures from all of the major phylogenetic groupings--Archaea, (eu)Bacteria, and the nucleus, mitochondrion, and chloroplast of Eucarya. Within this broad phylogenetic sampling are examples of the major forms of structural diversity currently known for this class of rRNAs. These structure diagrams are available online through our computer-network WWW server and anonymous ftp, as well as from the author in hardcopy format.
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This record was last updated on 07/02/2016 and may not reflect the most current and accurate biomedical/scientific data available from NLM.
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Near Realtime Maps of Possible Earthquake-Triggered Landslides
USGS scientists have been developing a system to quickly identify areas where landslides may have been triggered by a significant earthquake.Read Story
Mission Areas L2 Landing Page Tabs
Costs and consequences of natural hazards can be enormous; each year more people and infrastructure are at risk. We develop and apply hazards science to help protect U.S. safety, security, and economic well being. These scientific observations, analyses, and research are crucial for the Nation to become more resilient to natural hazards.Read Our Science Strategy
Explore the fascinating undersea world of coral reefs. Learn how we map, monitor, and model coral reefs so we can better understand, protect, and preserve our Nation's reefs.
Seafloor resource managers and modelers need seafloor maps that can be combined in GIS, modeling, and statistical analysis environments and related successfully to biologic and oceanographic data. The Marine Geomorphology, Evolution, and Habitats Project encompasses mapping activities and the development of new mapping systems and methodologies. The emphasis is on the role of geologic...
The FCMaP approach divides Florida into 6 regions that are geologically and physiographically distinct in terms of coastal characteristic.
An interactive, graphics-rich summary of the hazards in the HayWired Scenario.
Addressing issues concerning mineral resources that occur within the Exclusive Economic Zone of Pacific coastal States, Pacific islands of U.S. affiliation, and areas beyond national jurisdictions.
The Florida Coastal Mapping Program (FCMaP) is an initiative between Federal and Florida State agencies and institutions to coordinate and facilitate the collection and accessibility of Florida coastal seafloor data in order to fill priority areas and gaps.
Total water level (TWL) at the shoreline is the combination of tides, surge, and wave runup. A forecast of TWL is an estimate of the elevation where the ocean will meet the coast and can provide guidance on potential coastal erosion and flooding hazards.
Obique photos offer a unique perspective of the coast. Features such as beach erosion or accretion, dune erosion and overwash can all be clearly characterized in this imagery. It also documents coastal infrastructure, as well as the damage that infrastructure may incur as the result of an impacting hurricane.
Multibeam and multichannel sparker seismic-reflection data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA
Multibeam bathymetry and multichannel sparker seismic relfection data collected along the Queen Charlotte-Fairweather Fault between Icy Point and Dixon Entrance, offshore southeastern Alaska from 2016-05-17 to 2016-06-12.
Multichannel minisparker and chirp seismic-reflection data of field activity 2015-651-FA; Chatham Strait and Cross Sound, southeastern Alaska from 2015-08-03 to 2015-08-21
High-resolution multichannel minisparker and chirp seismic-reflection data were collected in August of 2015 to explore marine geologic hazards of inland waterways of southeastern Alaska. Sub-bottom profiles were acquired in the inland waters between Glacier Bay and Juneau, including Cross Sound and Chatham Strait.
Interpretive data release for Oregon Outer Continental Shelf Seafloor Mapping: Selected Lease Blocks Relevant to Renewable Energy
This data release includes the results of analysis of video data conducted by Oregon State University and the geo-habitat interpretation of multibeam echo sounder (MBES) data conducted by the USGS.
National Assessment of Shoreline Change: A GIS compilation of updated vector shorelines and associated shoreline change data for the north coast of Alaska, U.S. Canadian border to Icy Cape
This data release is an update to the original North Coast of Alaska data and includes revised rate-of-change calculations based on two additional shoreline positions data and improved rate metrics.
Interactive access to coastal change science and data for our Nation’s coasts. Information and products are organized within three coastal change hazard themes: 1) extreme storms, 2) shoreline change, and 3) sea-level rise. Each data item represents an individual research product, with some items grouped together as aggregates to show the breadth of the topic and make it easy to explore.
Publications of the Volcano Hazards Program 2011
The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity, as funded by Congressional appropriation. Investigations are carried out by the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute,...Nathenson, Manuel
National assessment of hurricane-induced coastal erosion hazards: Southeast Atlantic Coast
Beaches serve as a natural barrier between the ocean and inland communities, ecosystems, and natural resources. However, these dynamic environments move and change in response to winds, waves, and currents. During extreme storms, changes to beaches can be large, and the results are sometimes catastrophic. Lives may be lost, communities destroyed,...Stockdon, Hilary F.; Doran, Kara S.; Thompson, David M.; Sopkin, Kristin L.; Plant, Nathaniel G.
U.S. Geological Survey natural hazards science strategy: promoting the safety, security, and economic well-being of the Nation
The mission of the U.S. Geological Survey (USGS) in natural hazards is to develop and apply hazard science to help protect the safety, security, and economic well-being of the Nation. The costs and consequences of natural hazards can be enormous, and each year more people and infrastructure are at risk. USGS scientific research—founded on...Holmes, Robert R.; Jones, Lucile M.; Eidenshink, Jeffery C.; Godt, Jonathan W.; Kirby, Stephen H.; Love, Jeffrey J.; Neal, Christina A.; Plant, Nathaniel G.; Plunkett, Michael L.; Weaver, Craig S.; Wein, Anne; Perry, Suzanne C.
Operational Group Sandy technical progress report
Hurricane Sandy made US landfall near Atlantic City, NJ on 29 October 2012, causing 72 direct deaths, displacing thousands of individuals from damaged or destroyed dwellings, and leaving over 8.5 million homes without power across the northeast and mid-Atlantic. To coordinate federal rebuilding activities in the affected region, the President...
A mantle-driven surge in magma supply to Kīlauea Volcano during 2003--2007
The eruptive activity of a volcano is fundamentally controlled by the rate of magma supply. At Kīlauea Volcano, Hawai‘i, the rate of magma rising from a source within Earth’s mantle, through the Hawaiian hotspot, was thought to have been relatively steady in recent decades. Here we show that the magma supply to Kīlauea at least doubled during 2003...Poland, Michael P.; Miklius, Asta; Sutton, A. Jeff; Thornber, Carl R.
Relative azimuth inversion by way of damped maximum correlation estimates
Horizontal seismic data are utilized in a large number of Earth studies. Such work depends on the published orientations of the sensitive axes of seismic sensors relative to true North. These orientations can be estimated using a number of different techniques: SensOrLoc (Sensitivity, Orientation and Location), comparison to synthetics (Ekstrom...Ringler, A.T.; Edwards, J.D.; Hutt, C.R.; Shelly, F.
Publications of the Volcano Hazards Program 2009
The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Geologic Hazards Assessments subactivity as funded by congressional appropriation. Investigations are carried out in the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute,...Nathenson, Manuel
Report on the 2010 Chilean earthquake and tsunami response
In July 2010, in an effort to reduce future catastrophic natural disaster losses for California, the American Red Cross coordinated and sent a delegation of 20 multidisciplinary experts on earthquake response and recovery to Chile. The primary goal was to understand how the Chilean society and relevant organizations responded to the magnitude 8.8...
Geoinformatics in the public service: building a cyberinfrastructure across the geological surveys
Advanced information technology infrastructure is increasingly being employed in the Earth sciences to provide researchers with efficient access to massive central databases and to integrate diversely formatted information from a variety of sources. These geoinformatics initiatives enable manipulation, modeling and visualization of data in a...Keller, G. Randy; Baru, Chaitanya; Allison, M. Lee; Gundersen, Linda C.; Richard, Stephen M.
Segregating gas from melt: an experimental study of the Ostwald ripening of vapor bubbles in magmas
Diffusive coarsening (Ostwald ripening) of H2O and H2O-CO2 bubbles in rhyolite and basaltic andesite melts was studied with elevated temperature–pressure experiments to investigate the rates and time spans over which vapor bubbles may enlarge and attain sufficient buoyancy to segregate in magmatic systems. Bubble growth and segregation are also...Lautze, Nicole C.; Sisson, Thomas W.; Mangan, Margaret T.; Grove, Timothy L.
Whole-edifice ice volume change A.D. 1970 to 2007/2008 at Mount Rainier, Washington, based on LiDAR surveying
Net changes in thickness and volume of glacial ice and perennial snow at Mount Rainier, Washington State, have been mapped over the entire edifice by differencing between a highresolution LiDAR (light detection and ranging) topographic survey of September-October 2007/2008 and the 10 m lateral resolution U.S. Geological Survey digital elevation...Sisson, T.W.; Robinson, J.E.; Swinney, D.D.
Encounters of aircraft with volcanic ash clouds; A compilation of known incidents, 1953-2009
Information about reported encounters of aircraft with volcanic ash clouds from 1953 through 2009 has been compiled to document the nature and scope of risks to aviation from volcanic activity. The information, gleaned from a variety of published and other sources, is presented in database and spreadsheet formats; the compilation will be updated...Guffanti, Marianne; Casadevall, Thomas J.; Budding, Karin
Annotated drone image of Kīlauea Volcano's lower East Rift Zone fissure 8 lava channel. Image captured near Kapoho Crater looking east toward the ocean entry. Incandescent flow margin is more easily identified in the dark - specifically here in the area of Kapoho Beach Lots.
This animated GIF shows a sequence of radar amplitude images that were acquired by the Agenzia Spaziale Italiana CosmoSkyMed satellite system. The images illustrate changes to the...
Hawaiian Volcano Observatory geologist Matt Patrick acquires video of fissure 8 and the lava channel from Pohoiki Road/Highway 132. The video is used to document fountain behavior and lava flow characteristics, and how they change with time.
Lava flows around islands in the lava channel. The direction of flow is from the upper right to lower left. Field crews can make a rough calculation of velocity by timing large blocks as they pass between two landmarks that are a known distance apart.
Living and working on the Pacific islands hosting a key missile tracking site soon could be almost impossible due to the impacts of climate change.
Early in his college career, U.S. Geological Survey geophysicist Rufus Catchings became drawn to the mysteries that lie beneath the earth’s surface — and was determined to understand them.
The USGS Pacific Coastal and Marine Science Center hosted two back-to-back subduction-zone workshops in Santa Cruz, California, from February 5–8, 2018.
False-alarm tsunami alerts across the U.S. East Coast, Gulf of Mexico, and Caribbean prompt calls to USGS
USGS research geologist Curt Storlazzi led a workshop on “Understanding Flooding on Reef-lined Island Coastlines” (UFORIC) in Honolulu, Hawaiʻi, from 5–7 February.
Imagine dragging your outstretched fingers through wet beach sand, leaving long grooves behind. Scientists recently discovered enormous grooves buried under the seafloor near Costa Rica. The detailed three-dimensional data they used to uncover these corrugations can help them better understand large subduction zone earthquakes and related tsunamis worldwide.
The USGS Gas Hydrates Project has published two new Fact Sheets. One describes the goals and scope of the Project and the other describes "Gas Hydrates in Nature," including where they form, how they are studied, and why researchers focus on gas hydrates for energy resource and environmental studies.
USGS 360-degree videos of king tides show how rising seas will transform California beaches in the future
Acting deputy director of the USGS Pacific Coastal and Marine Science Center Nadine Golden attended a workshop on restoring a sand-mining operation on California’s Monterey Bay.
One week ago, on January 23rd at 12:31 a.m. local time, Alaskans were rocked by a magnitude 7.9 earthquake, with an epicenter in the Gulf of Alaska, about 350 miles southwest of Anchorage, and about 175 miles southeast of Kodiak Island. | <urn:uuid:4c84e860-e4dc-40d6-bcdc-859d49bc98fa> | 2.78125 | 2,823 | Content Listing | Science & Tech. | 35.119327 | 95,643,887 |
Did you make it to the Milky Way? That was my July homework assignment to you, as well as a line from the song “Drops of Jupiter,” by Train. I was reminded of my assignment as my department office manager, Angela, emailed me that title for a list of “celestial” songs I am compiling. I play a topical song while setting up for each Introductory Astronomy class. (YouTube allows me to easily do what was once difficult!)
The rest of September has a moonless, early night sky, so you still have time to sneak out to a dark sky and take in the magnificence of our home galaxy. The Milky Way arcs overhead from north to south, centered overhead just after dark.
You will notice dark patches in it – not areas lacking stars, but rather regions where clouds of dust in our galaxy block the view of more distant stars. This dust is not like the dust bunnies under your bed. This is composed of particles the size of what’s in cigarette smoke. These millionths-of-a-meter grains of silicon- and carbon-based minerals were cooked up in stars and released as the stars aged and died. They may well be the seeds of future stars.
If it were not for the dust in our Milky Way, you would be able to read this newspaper by the galaxy’s light. It limits our naked-eye view of stars to those within just a few thousand light years – just a few percent of what’s in our galaxy’s diameter of 100,000 light years.
Sorry, but you cannot see any individual stars millions of light years away, in spite of common misconceptions. The farthest you can see with your unaided eyes is on through our galaxy to two neighboring galaxies a couple of million light years away, which are seen as fuzzy patches rising in the northeast in our early evening autumn sky.
This dust was unknown to early astronomers William and Caroline Herschel. They counted the stars in their telescope’s view at hundreds of places along the Milky Way and got about the same number, concluding we must be at the galaxy’s center. (That’s like looking about in a fog and concluding that you were in the middle of the fog based on similar numbers of distant lights seen around you … except you can see the fog. But you can’t see the galaxy dust.)
Later astronomers found that we were not at the center of our galaxy. But it is our home, and it is composed of every star you see in the sky. And we ourselves are composed of stardust. So, be sure to make it to the Milky Way and see the dust whence we came.
Daniel B. Caton is a physics and astronomy professor and director of observatories at Appalachian State University. Email: firstname.lastname@example.org. More on this month’s column: www.upintheair.info. | <urn:uuid:6f4d9f6f-d620-49ff-aba9-1a86f344db80> | 3.171875 | 613 | Nonfiction Writing | Science & Tech. | 64.2025 | 95,643,900 |
A team of astronomers has identified possibly the coldest, faintest white dwarf star ever detected. This ancient stellar remnant is so cool that its carbon has crystallized, forming -- in effect -- an Earth-size diamond in space.
“It’s a really remarkable object,” said David Kaplan, a professor at the University of Wisconsin-Milwaukee. “These things should be out there, but because they are so dim they are very hard to find.”
Kaplan and his colleagues found this stellar gem using the National Radio Astronomy Observatory’s (NRAO) Green Bank Telescope (GBT) and Very Long Baseline Array (VLBA), as well as other observatories.
White dwarfs are the extremely dense end-states of stars like our Sun that have collapsed to form an object approximately the size of the Earth. Composed mostly of carbon and oxygen, white dwarfs slowly cool and fade over billions of years. The object in this new study is likely the same age as the Milky Way, approximately 11 billion years old.
Pulsars are rapidly spinning neutron stars, the superdense remains of massive stars that have exploded as supernovas. As neutron stars spin, lighthouse-like beams of radio waves, streaming from the poles of its powerful magnetic field, sweep through space. When one of these beams sweeps across the Earth, radio telescopes can capture the pulse of radio waves.
The pulsar companion to this white dwarf, dubbed PSR J2222-0137, was the first object in this system to be detected. It was found using the GBT by Jason Boyles, then a graduate student at West Virginia University in Morgantown.
These first observations revealed that the pulsar was spinning more than 30 times each second and was gravitationally bound to a companion star, which was initially identified as either another neutron star or, more likely, an uncommonly cool white dwarf. The two were calculated to orbit each other once every 2.45 days.
The pulsar was then observed over a two-year period with the VLBA by Adam Deller, an astronomer at the Netherlands Institute for Radio Astronomy (ASTRON). These observations pinpointed its location and distance from the Earth -- approximately 900 light-years away in the direction of the constellation Aquarius. This information was critical in refining the model used to time the arrival of the pulses at the Earth with the GBT.
By applying Einstein's theory of relativity, the researchers studied how the gravity of the companion warped space, causing delays in the radio signal as the pulsar passed behind it. These delayed travel times helped the researchers determine the orientation of their orbit and the individual masses of the two stars. The pulsar has a mass 1.2 times that of the Sun and the companion a mass 1.05 times that of the Sun.
These data strongly indicated that the pulsar companion could not have been a second neutron star; the orbits were too orderly for a second supernova to have taken place.
Knowing its location with such high precision and how bright a white dwarf should appear at that distance, the astronomers believed they should have been able to observe it in optical and infrared light.
Remarkably, neither the Southern Astrophysical Research (SOAR) telescope in Chile nor the 10-meter Keck telescope in Hawaii was able to detect it.
“Our final image should show us a companion 100 times fainter than any other white dwarf orbiting a neutron star and about 10 times fainter than any known white dwarf, but we don’t see a thing,” said Bart Dunlap, a graduate student at the University of North Carolina at Chapel Hill and one of the team members. “If there’s a white dwarf there, and there almost certainly is, it must be extremely cold.”
The researchers calculated that the white dwarf would be no more than a comparatively cool 3,000 degrees Kelvin (2,700 degrees Celsius). Our Sun at its center is about 5,000 times hotter.
Astronomers believe that such a cool, collapsed star would be largely crystallized carbon, not unlike a diamond. Other such stars have been identified and they are theoretically not that rare, but with a low intrinsic brightness, they can be deucedly difficult to detect. Its fortuitous location in a binary system with a neutron star enabled the team to identify this one.
A paper describing these results is published in the Astrophysical Journal.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
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National Radio Astronomy Observatory
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Charles Blue | Eurek Alert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
17.07.2018 | 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
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17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering | <urn:uuid:4877ba79-9000-47e7-a0d4-377c69251ba1> | 3.765625 | 1,672 | Content Listing | Science & Tech. | 42.690539 | 95,643,902 |
How are convection cells set up?
A self-contained zone in a fluid
If you are heating water in a pan on the stove, the water at thebottom of the pan will warm first. Since warm water is lighter, itwill rise, and cool water from the top will f…low down to replaceit. This is called convection, and will continue until all thewater is hot. Convection currents can occur in large bodies of water, in theatmosphere, or beneath the earth's crust. All that is needed is awarmer, lighter fluid below a cooler, heavier one.
convection warms and convention bake bakes
Heat transfer caused by fluids....
ask aico Mae belormino on facebokk diba? weh? we the sovereign.. etc. hahha XOXO Version 2
It is bumping into the lihosphere \n
A circular pattern of warm material rising and cool materiel sinking.
The force of the convection cell is bumping into the lithosphere which cause's it to turn at point a
because some people call the house number and not the cell
With all the heat under the crust into the mantle, the hot magma starts to move like any convection current so it goes up and then back around again to be reheated. at the top… the convection current is so strong it pulls the plates apart and magma seeps up through and becomes lava.
Matter doesn't move easily in solids.
remember this is a question u really need to think about. ANSWER: the force of it bumping into the lithospere resources: my brain the picture on the worksheet, and etc the… answer isnt ice cream that person just put it as a joke i may not be right think hard and reread | <urn:uuid:4c57b6e7-e9a1-4009-9bef-646601768871> | 4.15625 | 381 | Q&A Forum | Science & Tech. | 65.819887 | 95,643,905 |
git-symbolic-ref - Read, modify and delete symbolic refs
git symbolic-ref [-m <reason>] <name> <ref>
git symbolic-ref [-q] [--short] <name>
git symbolic-ref --delete [-q] <name>
Given one argument, reads which branch head the given symbolic ref refers to and
outputs its path, relative to the .git/
directory. Typically you would
as the <name> argument to see which branch your working
tree is on.
Given two arguments, creates or updates a symbolic ref <name> to point at
the given branch <ref>.
and an additional argument, deletes the given symbolic
A symbolic ref is a regular file that stores a string that begins with ref:
. For example, your .git/HEAD
is a regular file whose contents
is ref: refs/heads/master
Delete the symbolic ref <name>.
Do not issue an error message if the
<name> is not a symbolic ref but a detached HEAD; instead exit with
non-zero status silently.
When showing the value of <name> as a
symbolic ref, try to shorten the value, e.g. from refs/heads/master to
Update the reflog for <name> with
<reason>. This is valid only when creating or updating a symbolic
In the past, .git/HEAD
was a symbolic link pointing at
. When we wanted to switch to another branch, we did
ln -sf refs/heads/newbranch .git/HEAD
, and when we wanted to find out
which branch we are on, we did readlink .git/HEAD
. But symbolic links
are not entirely portable, so they are now deprecated and symbolic refs (as
described above) are used by default.
will exit with status 0 if the contents of the symbolic
ref were printed correctly, with status 1 if the requested name is not a
symbolic ref, or 128 if another error occurs.
Part of the git(1) | <urn:uuid:6d79ed34-e0e3-4cfa-875c-3b8625c39486> | 2.515625 | 440 | Documentation | Software Dev. | 60.671592 | 95,643,919 |
Special Issue "Catalytic Removal of Volatile Organic Compounds"
Deadline for manuscript submissions: closed (28 February 2015)
A printed edition of this Special Issue is available here.
Prof. Dr. Jean-François Lamonier
The degradation of air quality by the release of volatile organic compounds (VOC) into the air particularly harms human health and our environment. Regulation of outdoor VOC emissions are required to prevent the formation of ground-level ozone, which is principally responsible for photochemical smog. Indoor emissions of VOC have been the subject of recent consideration from many governments around the world because of the adverse impact of VOC on the health of people exposed to them.
Heterogeneous catalytic oxidation is regarded as the most promising technology to control VOC emission with low energy consumption and with selective conversion into harmless molecules. For this application, the use of engineered transition metal containing nanomaterials as catalysts is of interest because of the high price and limited resource of noble metals, most commonly used in practice due to their high intrinsic activity. Moreover, the high volume and low VOC concentrations in air could require the coupling of catalytic oxidation process with other technologies such as adsorption and non-thermal plasma in order to control the emission with reduced operating costs.
The aim of this special issue is to cover promising recent research and novel trends in the fields of outdoor and indoor VOC abatement using different technological approaches and including recent developments in material chemistry to achieve more efficient processes.
Prof. Dr. Jean-François Lamonier
Manuscript Submission Information
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1300 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.
- volatile organic compounds
- catalytic oxidation
- transition metal oxide
- noble metals
- coupling technologies
- non-thermal plasma | <urn:uuid:8a1f8f3f-c7da-4998-bef6-6cd744428d57> | 2.5625 | 630 | Knowledge Article | Science & Tech. | 24.542295 | 95,643,931 |
Based on fictional dinosaurs and squid, technology could protect soldiers and structures
Materials inspired by disappearing Hollywood dinosaurs and real-life shy squid have been invented by UCI engineers, according to new findings in Science this Friday.
The thin swatches can quickly change how they reflect heat, smoothing or wrinkling their surfaces in under a second after being stretched or electrically triggered. That makes them invisible to infrared night vision tools or lets them modulate their temperatures.
“Basically, we’ve invented a soft material that can reflect heat in similar ways to how squid skin can reflect light,” said corresponding author Alon Gorodetsky, an engineering professor. “It goes from wrinkled and dull to smooth and shiny, essentially changing the way it reflects the heat.”
Potential uses include better camouflage for troops and insulation for spacecraft, storage containers, emergency shelters, clinical care, and building heating and cooling systems.
“We were inspired both by science fiction and science fact – seeing dinosaurs disappear and reappear under an infrared camera in ‘Jurassic World’ and seeing squid filmed underwater do similar things,” said Gorodetsky. “So we decided to merge those concepts to design a really unique technology.”
Made of sandwiches of aluminum, plastic, and sticky tape, the material transforms from a wrinkled grey to a glossy surface when it is either pulled manually or zapped with voltage.
Products that reflect heat, such as emergency blankets, have existed for decades. But in the past several years, inventors in Gorodetsky’s lab and others have pushed to create dramatically improved versions via bio-inspired engineering. One focus has been to imitate how squid and other cephalopods can nearly instantaneously change their skin to blend into their surrounding environment.
Now, he and his team have done it, creating prototypes that can next be scaled up into large sheets of commercially useable material. Patents are pending.
“It was hard, especially the first phase when we were learning how to work with the sticky material,” said doctoral student Chengyi Xu, lead author. After trial-and-error processes involving thousands of attempts, he and postdoctoral scholar George Stiubianu finally saw the mirror-like coating change when they pulled it sideways.
“The whole project was so exciting.” he said.
Gorodetsky praised his team, saying, “These are exactly the type of graduate students and postdocs that UCI should be recruiting. They’re amazing.”
The Latest on: Invisibility material
via Google News
The Latest on: Invisibility material
Researchers Develop New Spectral Invisibility Cloak Like Nothing We’ve Seen Before
on July 9, 2018 at 10:28 pm
This means that they contain several different colors within them. The spectral invisibility cloak is designed to hide objects even under broadband illumination. The way it works is by selectively tra... […]
Invisibility breakthrough! New device makes stuff disappear
on July 8, 2018 at 12:04 pm
In concept, they say, it could be extended to make 3D objects invisible from all directions – a significant step in the development of practical invisibility cloaking technologies. Visit the WND Super... […]
Scientists dupe infrared cameras with thermal camouflage
on June 28, 2018 at 1:01 am
The rest of us, should we ever get to try out the material, will probably try to pretend we're wearing an invisibility cloak straight out of Harry Potter. […]
This Device Makes You Invisible to Thermal Imaging
on June 27, 2018 at 5:00 am
Harry Potter’s invisibility cloak seemed to do a good job of hiding ... In a paper released today in the journal Nano Letters, materials scientist Coskun Kocabas and his team announce that they’ve cre... […]
New algorithm can discover materials with unusual characteristics—including invisibility
on June 15, 2018 at 5:00 am
“With this algorithm, we can design new metamaterial properties on demand,” said Liu, an assistant professor of mechanical and industrial engineering. Credit: Adam Glanzman/Northeastern University Met... […]
Scientists Made a Working Invisibility Cloak (But There's a Catch)
on May 10, 2018 at 8:30 am
"So, we are working to open the floodgates to see what we can create with these materials." And since a lot of the “searching” we do underwater is using technology rather than the naked eye, this kind ... […]
Has invisibility material been created?
on April 2, 2018 at 8:15 am
Now you see it, now you don't? Researchers have developed a material that could make people or objects invisible to infrared night vision tools. The primary application would be military use. The mate... […]
Engineers create invisibility material
on April 1, 2018 at 8:42 pm
New York, April 1 (IANS) A team of engineers has invented a material that can help humans become invisible to infrared night vision tools. Based on fictional dinosaurs and squids, the material develop... […]
Fantasy no longer! Invisibility code cracked
on November 19, 2017 at 12:12 pm
In their real-world quest for invisibility, scientists at Ben-Gurion University ... transmit or otherwise shape electromagnetic radiation in ways that no natural material can, according to Nature.com. ... […]
via Bing News | <urn:uuid:d5c9112d-81aa-4b22-8754-b8dcf5f16756> | 3.65625 | 1,145 | Content Listing | Science & Tech. | 45.203856 | 95,643,941 |
Physics Question #9010
Kyler Tonkin, a 15 year old male from Kingston, Ontario asks on December 16, 2013,
I heard of an experiment that it is impossible to suck a liquid up a straw more than 10 meters. Is this a true experiment?
viewed 901 times
answered on December 17, 2013
Yes it's true. This has to do with the pressure of air at the surface of the earth. When water is "sucked" up a straw, it's not only your sucking that makes it come up, it's the pressure of all the air around you that does it. Everywhere on Earth there is a blanket of about 10 - 20km of air all pressing down on the surface of the planet and it's pressing on the container of water that's holding your straw. When you suck a bit of air out of the straw, all that air on the outside presses down on the water and pushes it up the straw. The most you can suck out of the straw in an ideal case is EVERYTHING--which creates a total vacuum in the straw. In that case the atmosphere presses down the maximum amount on the water and pushes it up the straw. This maximum pressure is equal to the air pressure at the surface of the earth, which on average is enough to push about 10m of water up a tube. After that, there's not enough air pressure to push it any higher. You can find this answer all over the internet. An even more interesting question is: if this is true--that 10m is the maximum height that water can be sucked up a tube, then how can trees that are over 100m tall "suck" up water all the way to the leaves at the top? The answer is here: http://www.science4all.org/le-nguyen-hoang/the-amazing-physics-of-water-in-trees. If you watch that video you will have much greater respect for the power of trees, and the laws of physics.
Add to or comment on this answer using the form below.
Note: All submissions are moderated prior to posting.
If you found this answer useful, please consider making a small donation to science.ca. | <urn:uuid:93085716-0971-45e0-b892-d7bce5f92cd9> | 3.328125 | 462 | Q&A Forum | Science & Tech. | 73.236667 | 95,643,965 |
This problem focuses on Dienes' Logiblocs. What is the same and what is different about these pairs of shapes? Can you describe the shapes in the picture?
How can you put five cereal packets together to make different shapes if you must put them face-to-face?
We have a box of cubes, triangular prisms, cones, cuboids, cylinders and tetrahedrons. Which of the buildings would fall down if we tried to make them?
A toy has a regular tetrahedron, a cube and a base with triangular and square hollows. If you fit a shape into the correct hollow a bell rings. How many times does the bell ring in a complete game?
How many different shapes can you make by putting four right- angled isosceles triangles together?
How many different ways can you find to join three equilateral triangles together? Can you convince us that you have found them all?
Here are shadows of some 3D shapes. What shapes could have made them?
How many balls of modelling clay and how many straws does it take to make these skeleton shapes?
You want to make each of the 5 Platonic solids and colour the faces so that, in every case, no two faces which meet along an edge have the same colour.
Find all the different shapes that can be made by joining five equilateral triangles edge to edge.
Each of the nets of nine solid shapes has been cut into two pieces. Can you see which pieces go together?
This activity challenges you to make collections of shapes. Can you give your collection a name?
Where can you put the mirror across the square so that you can still "see" the whole square? How many different positions are possible?
Can you arrange the shapes in a chain so that each one shares a face (or faces) that are the same shape as the one that follows it?
On which of these shapes can you trace a path along all of its edges, without going over any edge twice?
Can you make these equilateral triangles fit together to cover the paper without any gaps between them? Can you tessellate isosceles triangles?
Read about David Hilbert who proved that any polygon could be cut up into a certain number of pieces that could be put back together to form any other polygon of equal area.
You can trace over all of the diagonals of a pentagon without lifting your pencil and without going over any more than once. Can the same thing be done with a hexagon or with a heptagon?
This investigation explores using different shapes as the hands of the clock. What things occur as the the hands move. | <urn:uuid:95b4295d-ce53-4777-91ad-ac63949af6e3> | 4.0625 | 554 | Content Listing | Science & Tech. | 59.081563 | 95,643,966 |
Washington: A new study has revealed that Milky Way galaxy may be 50 percent larger than commonly estimated as its galactic disk is contoured into several concentric ripples.
The research, conducted by an international team led by Rensselaer Polytechnic Institute Professor Heidi Jo Newberg, revisited astronomical data from the Sloan Digital Sky Survey which, in 2002, established the presence of a bulging ring of stars beyond the known plane of the Milky Way.
The findings showed that the features previously identified as rings are actually part of the galactic disk , extending the known width of the Milky Way from 100,000 light years across to 150,000 light years, said Yan Xu, a scientist at the National Astronomical Observatories of China (which is part of the Chinese Academy of Science in Beijing), former visiting scientist at Rensselaer, and lead author of the paper.
The new research was built upon a 2002 finding in which Newberg established the existence of the "Monoceros Ring," an "over-density" of stars at the outer edges of the galaxy that bulges above the galactic plane.
At the time, Newberg noticed evidence of another over-density of stars, between the Monoceros Ring and the sun, but was unable to investigate further. With more data available from the SDSS, researchers recently returned to the mystery.
When researchers revisited the data, they found four anomalies: one north of the galactic plane at 2 kilo-parsecs (kpc) from the sun, one south of the plane at 4-6 kpc, a third to the north at 8-10 kpc, and evidence of a fourth to the south 12-16 kpc from the sun.
The Monoceros Ring was associated with the third ripple. The researchers further found that the oscillations appear to line up with the locations of the galaxy's spiral arms.
Newberg said the findings supported other recent research, including a theoretical finding that a dwarf galaxy or dark matter lump passing through the Milky Way would produce a similar rippling effect. In fact, the ripples might ultimately be used to measure the lumpiness of dark matter in our galaxy.
The study is published in the Astrophysical Journal. | <urn:uuid:28384581-6915-46f2-bf8b-370c04ed1a42> | 3.296875 | 458 | News Article | Science & Tech. | 36.490753 | 95,643,977 |
The looparray statement is used at the beginning of a loop that loops over the elements of an array.
This statement has four parameters:
array – is a formula that calculates the array to be scanned. This could be a field or variable, or a complex formula.
sep – is the array’s separator character.
element – is the name of a field or variable where each array element will be stored. If this field or variable does not already exist it will be created as a local variable.
index – is the name of a field or variable where the loop count will be stored. If this field or variable does not already exist it will be created as a local variable. (Note: This parameter is optional – if you don’t need to know the loop count, you can leave this parameter off.
The looparray statement is used at the beginning of a loop that iterates over a text array (see Text Arrays and Loop more information on these topics). LoopArray loops are always terminated with an endloop statement.
When the loop starts, Panorama calculates the text array (based on the formula in the first parameter) and makes a copy of it. Each time through the loop Panorama extracts the next element from the array for processing. In other words, the first time through the loop the first element is processed, then the next time through the second element is processed, etc. The loop repeats until all of the array elements have been processed.
Here is a simple example that loops once for each word in the Notes field.
looparray Notes," ",word message word endloop
If the Notes field contains Now is the time the message alert will appear four times, once for each word.
Adding a fourth parameter to the looparray statement allows you to access the number of times the loop has repeated so far.
looparray Notes," ",word,wordnumber message wordnumber+": "+word endloop
Again, if the Notes field contains Now is the time the message alert will appear four times, but this time each word will be numbered like this:
☞ 1: Now ☞ 2: is ☞ 3: the ☞ 4: time
It’s possible to create a loop that iterates over an array without using the looparray statement. For example, the previous example could be written like this:
local word,wordnumber for wordnumber,1,arraysize(Notes," ") word=array(Notes,wordcount," ") message wordnumber+": "+word wordnumber=wordnumber+1 endloop
As you can see, writing the loop this way takes six lines instead of three. Using looparray is also significantly faster, especially with large arrays, because looparray uses special optimizations to reduce the amount of processing that needs to be done on the array each time through the loop. In some cases it may even be worthwhile to rewrite old code to use looparray instead of other types of loop statements.
Note: If the text array is empty, the statements in the loop are skipped without even executing them once.
LOOP without ENDLOOP – Each FOR statement must be paired with a corresponding ENDLOOP, UNTIL or WHILE statement. If this error message appears, the necessary statement terminating the loop has not been included.
LOOPARRAY element parameter must be a field or variable – The ELEMENT parameter must be a field or variable, it cannot be a more complex calculation.
LOOPARRAY index parameter must be a field or variable – The INDEX parameter must be a field or variable, it cannot be a more complex calculation.
|10.0||New||New in this version| | <urn:uuid:7a5f256a-1d5e-428f-aad3-d645a875ba9f> | 3.03125 | 762 | Tutorial | Software Dev. | 46.191108 | 95,643,987 |
The embryonic nervous system is a hollow tube consisting of elongated neural progenitor cells, which extend from the inner to the outer surface of the tube. In a section inside the tube called the ventricular zone (VZ), these cells divide and produce immature neurons that migrate outwards. This involves well-characterized movements that are coupled to cell division. After a cell divides at the inner-most VZ region, the nuclei migrate to the outer region, where they synthesize new DNA before returning.
Figure 1: Cell nuclei of brain cells accumulate at the outer surface of the ventricular zone when the cell cycle is blocked. Copyright : 2011 Yoichi Kosodo et al.
To determine how the direction of movement is coupled to the cell division cycle, Yoichi Kosodo and colleagues in Matsuzaki's group at RIKEN Center for Developmental Biology labeled nuclei in the embryonic mouse brain with green fluorescent protein. This enabled them to not only track their movements in cultured brain slices using a video-imaging system, but also correlate their positions with phases of the cell cycle. They found that outward nuclear migration involves back and forth ‘ratcheting’ motions and occurs more slowly than inward migration.
Importantly, they discovered that blocking the cell cycle before DNA synthesis caused nuclei to accumulate at the outer VZ surface (Fig.1), and reduced outward migration. Nuclei migrating back inwards normally crowd out those just finished dividing, thus pushing them away from the inner VZ surface.
Examining their results further, the researchers computationally modeled nuclear migration, and incorporated fluorescent magnetic beads into the inner VZ surface. They observed the beads moving away from the inner VZ surface, and remaining at its outer region.
The researchers also showed that inward migration is closely linked to microtubule reorganization orchestrated by a protein called Tpx2, which is initially expressed in the nuclei of progenitors before moving to the mitotic spindle. This separates newly duplicated chromosomes. Translocation of Tpx2 to the cell region nearest the inner VZ surface promotes migration of the nucleus in that direction by microtubule re-organization. Reducing Tpx2 activity lowered the velocity of inward migration, but introducing the human Tpx2 gene into the cells lacking Tpx2 restored normal speed.
The researchers conclude that two mechanisms maintain brain structure during development. One couples cell migration to the cell cycle, and occurs independently of other cells, with Tpx2 providing an active driving force; and the other involves interactions between the nuclei in the VZ.
The corresponding author for this highlight is based at the Laboratory for Cell Asymmetry, RIKEN Center for Developmental Biology
Kosodo, Y., Suetsugu, T., Suda, M., Mimori-Kiyosue, Y., Toida, K., Baba, S. A., Kimura, A. & Matsuzaki, F. Regulation of interkinetic nuclear migration by cell cycle-coupled active and passive mechanisms in the developing brain. The EMBO Journal 30, 1690–1704 (2011).
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...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences | <urn:uuid:784e4eba-685f-42c6-88e8-d25e617cac8c> | 3.375 | 1,290 | Content Listing | Science & Tech. | 36.798342 | 95,643,997 |
Peter Swarzenski: The Arctic is heating up faster than many other places in the world, so we want to work there to look at the response of the environment to these rapid changes.
(pictures showing the geometrical shapes of permafrost, and then images of the coast and Barter Island)
Barter Island sits at the top of the Arctic National Wildlife Refuge—at 70 degrees north latitude, just 70 miles west of the Canada border. On this tundra island reside nearly 250 residents in a remote Alaskan village most have not heard of called Kaktovik.
(video of USGS working on the ocean bluffs in snow and wind. Following this are shots of delayed flight times, the landscape when sunny and then foggy, and imagery of airports and moving bags)
The weather here can be inhospitable at times—the year’s average temperature is below freezing, which can make working outside pretty difficult. Yet the greater challenge can be in just getting to the island. The fog around Barter can mean days and days of delayed flights, waiting around at the airport, and many trips hauling gear back and forth.
(pause to show everyone aboard the flight)
So the scientists are clearly happy when they’re finally on their way.
(intercom on airplane: “... at row 4 we have two window exits—one on either side of the cabin...”
USGS researchers want to know what’s making bluffs erode so quickly along the North Slope. Is the treeless, frozen land, or permafrost tundra, thawing faster and deeper as Arctic temperatures warm? And if so, is that thawing helping to speed up erosion once the storm waves hit? Is the shrinking sea ice also part of the problem?
(aerial shots and time-lapse shot of bluffs showing collapse and storm activity
Bruce Richmond: What we’ve seen these last few years is a lot of melting on the actual bluff surface, creating small streams. On our recent trip, we were there for 4 or 5 days, and the size of the streams ... we could visibly see them growing.
(shots showing Bruce working and walking on the tundra. Streams flowing and signs of thawing mud are visible).
They also gather other bits of data for a wider view of what’s changing in the Arctic—and what’s triggering it. In some places like Drew Point, Alaska, nearly 20 meters of bluffs can erode in a year. In Kaktovik...
(a panoramic shot, and one showing a large chunk of icy bluffs fallen from the coast)
Bruce: Erosion rates there are fairly moderate, averaging about 1.3 meters/year for the tundra bluffs. But it’s punctuated by storm events, where in a single storm you can get several meters of erosion.
(footage of waves rolling into the coast)
So they snap photos of the coastline from planes; they measure how much the shoreline has shifted the past 60 years; and they use time-lapse cameras to capture big storms and erosion along the bluffs.
(aerial shots of the coast, historical images of the coastline showing how much coastline has changed in 600 years—100 meters—and a still shot of a local resident pointing at a time lapse camera)
Bruce: We’re also coring to look at the internal geology of the bluffs. We work with local Iñupiats in their boats. We’ll also work with the locals using ATVS. We’ve been collecting repeat photography of the bluff face along Barter Island, so we can actually look at specific changes through time.
(video of scientists along the bluffs drilling into the permafrost and holding out an icy, muddy core. Then shots of USGS staff aboard an Iñupiat boat and on an ATV, with a series of bluff shots from the ATV stitched together.)
Peter Swarzenski and Cordell Johnson also test how electricity flows through the icy ground, which tells them how the permafrost is constructed.
(still images showing Peter walking across tundra with their gear and laying out the electrical lines. One image shows a small crevasse in the permafrost.)
Peter: The surface is actually really complicated. How consistent is the permafrost as you go down or across the surface? It’s not a simple layer of frozen sediment.
And then we can run chemical analyses. For example, what the salinity of the permafrost is at depths. How old is the permafrost at 1 meter or at 2 meters or at 5 meters?
(still images and video showing cores being collected and landscape where scientists are drilling into the permafrost)
More trips to the area are planned to resolve how the water flowing beneath the permafrost—called groundwater—can influence erosion.
Peter: If 10 meters are being eroded every year, you want to know what this place is going to look like in 10 or 20 years. So knowing something about how fragile these coastal bluffs are, is really useful.
(ends with a series of coastal shots, waves, and failing bluffs, plus one coastal shot from Wainwright, Alaska, showing reinforced sandbags along the cliffs)
Science voices: Peter Swarzenski and Bruce Richmond
Produced by: Amy West
Video footage: Amy West, Bruce Richmond, Tom Lorenson
Music: Going Forward Looking Back and Massive by Podington Bear, from an Attribution, NonCommercial International Creative Common license. 3.0, ©Chad Crouch
Photo credits: Ann Gibbs, Peter Swarzenski, Bruce Richmond, Li Erikson, Tom Lorenson, Christopher Arp
Special thanks: Cordell Banks, UC Santa Cruz, the City of Kaktovik, Kaktovik Iñupiat Corporation, U.S. Fish and Wildlife Service | <urn:uuid:6ccc8845-7b40-4e9f-9781-89264e3ef5ae> | 3.1875 | 1,256 | Audio Transcript | Science & Tech. | 56.369969 | 95,644,008 |
Molecular Anvils Trigger Chemical Reactions by Squeezing
News Feb 22, 2018 | Original Story from SLAC National Accelerator Laboratory.
Illustration of a diamond anvil cell, where samples can be compressed to very high pressures between the flattened tips of two diamonds. Credit: Argonne National Laboratory, Greg Stewart/SLAC National Accelerator Laboratory.
Scientists have turned the smallest possible bits of diamond and other super-hard specks into “molecular anvils” that squeeze and twist molecules until chemical bonds break and atoms exchange electrons. These are the first such chemical reactions triggered by mechanical pressure alone, and researchers say the method offers a new way to do chemistry at the molecular level that is greener, more efficient and much more precise.
The research was led by scientists from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University, who reported their findings in Nature today.
“Unlike other mechanical techniques, which basically pull molecules until they break apart, we show that pressure from molecular anvils can both break chemical bonds and trigger another type of reaction where electrons move from one atom to another,” said Hao Yan, a physical science research associate at SIMES, the Stanford Institute for Materials and Energy Sciences, and one of the lead authors of the study.
“We can use molecular anvils to trigger changes at a specific point in a molecule while protecting the areas we don’t want to change,” he said, “and this creates a lot of new possibilities.”
A reaction that’s mechanically driven has the potential to produce entirely different products from the same starting ingredients than one driven the conventional way by heat, light or electrical current, said study co-author Nicholas Melosh, a SIMES investigator and associate professor at SLAC and Stanford. It’s also much more energy efficient, and because it doesn’t need heat or solvents, it should be environmentally friendly.
Putting the Squeeze on Materials with Diamonds
The experiments were carried out with a diamond anvil cell about the size of an espresso cup in the laboratory of paper co-author Wendy Mao, an associate professor at SLAC and Stanford and an investigator with SIMES, which is a joint SLAC/Stanford institute.
Diamond anvil cells squeeze materials between the flattened tips of two diamonds and can reach tremendous pressures – over 500 gigapascals, or about one and a half times the pressure at the center of the Earth. They’re used to explore what minerals deep inside the Earth are like and how materials under pressure develop unusual properties, among other things.
These pressures are reached in a surprisingly straightforward way, by tightening screws to bring the diamonds closer together, Mao said. “Pressure is force per unit area, and we are compressing a tiny amount of sample between the tips of two small diamonds that each weigh only about a quarter of a carat,” she said, “so you only need a modest amount of force to reach high pressures.”
Since the diamonds are transparent, light can go through them and reach the sample, said Yu Lin, a SIMES associate staff scientist who led the high-pressure part of the experiment.
“We can use a lot of experimental techniques to study the reaction while the sample is compressed,” she said. “For instance, when we shine an X-ray beam into the sample, the sample responds by scattering or absorbing the light, which travels back through the diamond into a detector. Analyzing the signal from that light tells you if a reaction has occurred.”
What usually happens when you squeeze a sample is that it deforms uniformly, with all the bonds between atoms shrinking by the same amount, Melosh said.
Yet this is not always the case, he said: “If you compress a material that has both hard and soft components, such as carbon fibers embedded in epoxy, the bonds in the soft epoxy will deform a whole lot more than the ones in the carbon fiber.”
They wondered if they could harness that same principle to bend or break specific bonds in an individual molecule.
What got them thinking along those lines was a series of experiments Melosh’s team had done with diamondoids, the smallest possible bits of diamond, which are invisible to the naked eye and weigh less than a billionth of a billionth of a carat. Melosh co-directs a joint SLAC-Stanford program that isolates diamondoids from petroleum fluid and looks for ways to put them to use. In a recent study, his team had attached diamondoids to smaller, softer molecules to create Lego-like blocks that assembled themselves into the thinnest possible electrical wires, with a conducting core of sulfur and copper.
Like carbon fibers in epoxy, these building blocks contained hard and soft parts. If put into a diamond anvil, would the hard parts act as mini-anvils that squeeze and deform the soft parts in a non-uniform way?
The answer, they discovered, was yes.
Tiny Anvils Open New Possibilities
For their first experiments, they used copper sulfur clusters – tiny particles consisting of eight atoms – attached to molecular anvils made of another rigid molecule called carborane. They put this combination into the diamond anvil cell and cranked up the pressure.
When the pressure got high enough, atomic bonds in the cluster broke, but that’s not all. Electrons moved from its sulfur atoms to its copper atoms and pure crystals of copper formed, which would not have occurred in conventional reactions driven by heat, the researchers said. They discovered a point of no return where this change becomes irreversible. Below that pressure point, the cluster goes back to its original state when pressure is removed.
Computational studies revealed what had happened: Pressure from the diamond anvil cell moved the molecular anvils, and they in turn squeezed chemical bonds in the clusters, compressing them at least 10 times more than their own bonds had been compressed. This compression was also uneven, Yan said, and it bent or twisted some of the cluster's bonds in a way that caused bonds to break, electrons to move and copper crystals to form.
Other experiments, this time with diamondoids as molecular anvils, showed that small changes in the sizes and positions of the tiny anvils can make the difference between triggering a reaction or protecting part of a molecule so it doesn’t bend or react.
The scientists were able to observe these changes with several techniques, including electron microscopy at Stanford and X-ray measurements at two DOE Office of Science user facilities – the Advanced Light Source at Lawrence Berkeley National Laboratory and the Advanced Photon Source at Argonne National Laboratory.
“This is exciting, and it opens up a whole new field,” Mao said. “From our side, we’re interested in looking at how pressure can affect a wide range of technologically interesting materials, from superconductors that transmit electricity with no loss to halide perovskites, which have a lot of potential for next-generation solar cells. Once we understand what’s possible from a very basic science point of view we can think about the more practical side.”
Going forward, the researchers also want to use this technique to look at reactions that are hard to do in conventional ways and see if compression makes them easier, Yan said.
“If we want to dream big, could compression help us turn carbon dioxide from the air into fuel, or nitrogen from the air into fertilizer?” he said. “These are some of the questions that molecular anvils will allow people to explore.”
This article has been republished from materials provided by SLAC National Accelerator Laboratory. Note: material may have been edited for length and content. For further information, please contact the cited source.
Sterically controlled mechanochemistry under hydrostatic pressure. Hao Yan, Fan Yang, Ding Pan, Yu Lin, J. Nathan Hohman, Diego Solis-Ibarra, Fei Hua Li, Jeremy E. P. Dahl, Robert M. K. Carlson, Boryslav A. Tkachenko, Andrey A. Fokin, Peter R. Schreiner, Giulia Galli, Wendy L. Mao, Zhi-Xun Shen & Nicholas A. Melosh. Nature volume 554, pages 505–510 (22 February 2018) doi:10.1038/nature25765.
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Q: Why are there humpback whales in San Francisco Bay right now? What attracted them here, and what are they finding to eat? — Beth Slatkin, Bay Nature marketing director
Yes, it’s been great to have whales in the Bay! Not just one or two, but up to a dozen humpback whales can be seen spouting simultaneously. Last summer was the first time we experienced a major influx of humpbacks. From sightings made so far, this year is on track to equal the 2016 count. That’s amazing when you consider that, in the past, humpback whales only ventured into the Bay accidentally. Humphrey was the most famous of these lost whales. In 1985, he swam 70 miles up the Sacramento River before he turned around. And in 2007, Delta and Dawn, a humpback mother and calf, were disoriented and spent a month in the estuary before they made it back to the sea.
Today’s humpbacks, however, are definitely not disoriented whales. They’re here intentionally to feast on fish, especially schooling anchovy, which enter the Bay by the millions. Humpbacks feed on fish, or the tiny crustaceans we call krill. When the krill begin to “bloom” in vast numbers offshore in the Gulf of the Farallones, usually by August, the humpbacks will turn their attention there. But until then, the humpbacks are taking advantage of the Bay’s bounty. You can sometimes see them lunging to the surface, their huge throats distended as they engulf a shoal of anchovies.
While the whales have been around since April, they are not permanent residents. Rather, they commute to and from the outer coast in a rhythm that’s timed to the tides. Typically, they enter the Bay on the incoming flood tide and leave on the ebb. The best spot we’ve found to count the whales is atop the Marin Headlands, or from Lands End in San Francisco. You can get closer if you book a tour on a local whale watch boat. But if you want to get a special view, without having to worry about seasickness, then go to the Golden Gate Bridge during a strong rising tide. From the pedestrian walkway or the platform around the South Tower humpbacks can be seen — and even heard — blowing as they forage for anchovy, often accompanied by squealing gulls vying for leftovers.
The same whales don’t seem to visit the Bay every single day. We know this because we can track individual humpback whales by comparing photos of the flukes, their massive tails. The undersides of their flukes, which they lift high into the air, have natural black-and-white patterns we can recognize like fingerprints. By matching fluke photo-ID images, we learned that at least a few whales identified in 2016 returned in 2017. That’s not surprising, given they are adept at navigating the marine environment and highly motivated to eat. The adults lose weight as they fast on their winter breeding grounds off southern Mexico and Central America, so in spring they head to California where they can bulk up.
Why did it take so long for the humpbacks to target San Francisco Bay? It could be that they didn’t need to explore this area until their population grew and they began to seek out new sources of food. When I started studying whales in the mid-1970s, there were about 2,000 humpback whales in the North Pacific. Now there are more than 20,000. That’s what happens when you stop hunting them.
Threats to our local humpbacks still exist, however. The risk of being struck by a ship increases as the whales transit through the narrow strait into the Bay, along with recreational boaters approaching them too closely. It looks like humans are going to have to make room for these ocean giants. What we thought would be a once-in-a-lifetime experience last year may become repeat performances if the humpbacks continue to spend summers beneath the Golden Gate Bridge. Lucky us. There’s no better place in the world to look straight down into the blowholes of a great whale!
Bill Keener is a marine biologist with Golden Gate Cetacean Research, a nonprofit organization devoted to the study of whales, dolphins and porpoises of the San Francisco Bay Area. To report your sightings of whales in the Bay, please go to www.ggcetacean.org.
Ask the Naturalist is a reader-funded bimonthly column with the California Center for Natural History that answers your questions about the natural world of the San Francisco Bay Area. Have a question for the naturalist? Fill out our question form or email us at atn at baynature.org!
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“Equinox Cracks” Forming in Earth’s Magnetic Field
March 11. 2018: The vernal equinox is less than 10 days away. That means one thing: Cracks are opening in Earth’s magnetic field. Researchers have long known that during weeks around equinoxes fissures form in Earth’s magnetosphere. Solar wind can pour through the gaps to fuel bright displays of Arctic lights. One such episode occurred on March 9th.
During the display, a stream of solar wind was barely grazing Earth’s magnetic field. At this time of year, that’s all it takes. Even a gentle gust of solar wind can breach our planet’s magnetic defenses.
This is called the “Russell-McPherron effect,” named after the researchers who first explained it. The cracks are opened by the solar wind itself. South-pointing magnetic fields inside the solar wind oppose Earth’s north-pointing magnetic field. The two, N vs. S, partially cancel one another, weakening our planet’s magnetic defenses. This cancellation can happen at any time of year, but it happens with greatest effect around the equinoxes. Indeed, a 75-year study shows that March is the most geomagnetically active month of the year, followed closely by September-October–a direct result of “equinox cracks.”
NASA and European spacecraft have been detecting these cracks for years. Small ones are about the size of California, and many are wider than the entire planet. While the cracks are open, magnetic fields on Earth are connected to those on the sun. Theoretically, it would be possible to pick a magnetic field line on terra firma and follow it all the way back to the solar surface. There’s no danger to people on Earth, however, because our atmosphere protects us, intercepting the rain of particles. The afterglow of this shielding action is called the “aurora borealis.”
The Sun Is Dimming
Dec. 15, 2017: On Friday, Dec. 15th, at the Cape Canaveral Air Force Station in Florida, SpaceX launched a new sensor to the International Space Station named TSIS-1. Its mission: to measure the dimming of the sun. As the sunspot cycle plunges toward its 11-year minimum, NASA satellites are tracking a decline in total solar irradiance (TSI). Across the entire electromagnetic spectrum, the sun’s output has dropped nearly 0.1% compared to the Solar Maximum of 2012-2014. This plot shows the TSI since 1978 as observed from nine previous satellites:
The rise and fall of the sun’s luminosity is a natural part of the solar cycle. A change of 0.1% may not sound like much, but the sun deposits a lot of energy on the Earth, approximately 1,361 watts per square meter. Summed over the globe, a 0.1% variation in this quantity exceeds all of our planet’s other energy sources (such as natural radioactivity in Earth’s core) combined. A 2013 report issued by the National Research Council (NRC), “The Effects of Solar Variability on Earth’s Climate,” spells out some of the ways the cyclic change in TSI can affect the chemistry of Earth’s upper atmosphere and possibly alter regional weather patterns, especially in the Pacific.
NASA’s current flagship satellite for measuring TSI, the Solar Radiation and Climate Experiment (SORCE), is now more than six years beyond its prime-mission lifetime. TSIS-1 will take over for SORCE, extending the record of TSI measurements with unprecedented precision. It’s five-year mission will overlap a deep Solar Minimum expected in 2019-2020. TSIS-1 will therefore be able to observe the continued decline in the sun’s luminosity followed by a rebound as the next solar cycle picks up steam. Installing and checking out TSIS-1 will take some time; the first science data are expected in Feb. 2018.
Extracts from “Volcanic Influences on the Atmosphere”
Earth is experiencing a bit of a volcanic lull. We haven’t had a major volcanic blast since 1991 when Mt Pinatubo awoke from a 500 year slumber and sprayed ten billion cubic meters of ash, rock and debris into Earth’s atmosphere. Recent eruptions have been puny by comparison and have failed to make a dent on the stratosphere. From “Two Centuries of Volcanic Aerosols Derived from Lunar Eclipse Records” by R. A. Keen
A transparent stratosphere “lets the sunshine in” and actually helps warm the Earth below. “The lunar eclipse record indicates a clear stratosphere has contributed about 0.2 degrees to warming since the 1980s.”
“Mt. Pinatubo finished a 110-year episode of frequent major eruptions that began with Krakatau in 1883,” he says. “Since then, lunar eclipses have been relatively bright, and the Jan. 31st 2018 eclipse should be no exception.”
Extracts from “Arctic radar to probe ‘space weather’”
By Jonathan Amos BBC Science Correspondent
- 23 August 2017
The UK is to contribute to a sophisticated new radar system in the Arctic to study “space weather”.
This phenomenon describes the effects on Earth’s wider environment as it is constantly bombarded by particles and magnetic energy from the Sun. The impacts can damage satellites and even disrupt electricity grids.
The radar, to be built across Norway, Sweden and Finland by the European Incoherent Scatter Association (EISCAT), should come online in 2021. The international organisation already operates radar facilities in the far north, but the new technology is regarded as a big step forward in capability. “This is the next generation,” said Dr Andrew Kavanagh, a EISCAT member scientist working with the British Antarctic Survey (BAS).”The system will look like a flat field of antennas, much like some of the big radio astronomy telescopes such as LOFAR and SKA. We will be able to do a lot more with this new system – looking at large parts of the sky simultaneously. A 3D view of the sky.”
The Sun perpetually billows clouds of magnetic energy and plasma (a gas of electrically charged particles) in all directions. But often great eruptions of this emission are directed straight at Earth. When these interact with our planet’s own magnetic field and atmosphere, they set off all manner of disturbances. The Aurora Borealis is one such consequence, as particles are accelerated downwards to collide with air molecules to produce colourful curtains of light in high-latitude skies. But there are more concerning interactions that can lead to upsets in spacecraft electronics, drop-outs in radio communications, and surges in power networks on the ground.
The new radar system will be set up at Skibotn in Norway, near Kiruna in Sweden, and near Kaaresuvanto in Finland. Skibotn will have a transmitter and receiver array, while the two other locations will have receiver arrays. The technology will enable scientists to probe in detail the ionosphere – the region of the Earth’s upper-atmosphere that ranges from about 70km to 1,000km in altitude. It will sample the electron concentration and temperature, and the ion temperature and velocity at various heights along the radar beam direction
Some of the interactions can stimulate currents that then heat the high atmosphere. This is a particular interest for some UK scientists.
The heating can alter the density of air molecules at altitudes where low-orbiting satellites move. This perturbs their trajectory ever so slightly. And by the same token, it also changes the path of redundant hardware, or “space junk”, speeding up or slowing down the time it takes for this material to fall back to Earth.
If the ordinary citizen is to realistically assess the true impact of solar variability on earthly climate, to make some kind of sense of the ifs, whethers and suppositions, perhaps the most realistic method is to see if we can identify specific climate events in recent history and cross reference that to the kind of detailed solar records we now have available to see if any sensible match can be identified.
As an example, if we examine known, well recorded, events over the last couple of decades, for example the ’European Heat Wave of 2003’, the ‘Winter Cold 2009/10/11’ then cross reference those events with charts of solar activity then, yes of course, the heat wave did occur during solar max and the cold winters did occur during solar minimum. However there does not appear to be any serious, specific sunspot activity that would explain the extreme nature of those events, indeed sunspot activity seemed to be ‘pretty average’ for that part of the cycle at those specific times.
Until, that is, we examine the ‘Ap’ index where we find a massive spike in recorded activity at the time of the 2003 heat wave together with deep dips in activity December 09/10/11/12. These dips actually running counter to the overall rise in sunspot activity during that period.
This would imply that the impact of geo-effective activity from solar sources other than just the sunspots does make a greater contribution to climate variability than is generally accepted.
This is achieved through the interaction with the upper atmospheric profile, rather than just the pure injection of energy. It needs also to be remembered that this profile variation does have an effect on surface climate through the movement of surface air masses; this can give the impression of warming when cooling is actually taking place – and vice versa – and can contribute to cooling by throwing increased amounts of warm, tropical air towards the poles from where the energy will, of course, eventually, radiate away.
So, can we expect to always have a direct correlation between solar impacts and global climate ?
Well no, not really. Much depends on the situation on the ground at the time; the pre-existing conditions are all important in determining what happens at the time of any impact.
The likelihood exists, of course, that overall solar behaviour at any one time will have pre-determined the general situation on the ground. Peak solar activity in the years prior to 2003 will have both made an upsurge in Ap activity more likely and pre-disposed the global climate towards a positive result for such an impact. Occurring as it did at the peak of northern summer it was at exactly the right time to give the result noted. Similarly, low activity during solar minimum will have exacerbated both the likelihood of a dip and the potential results of a sharp reduction in activity which, occurring in November/December each year gave the very cold winters experienced.
The question remains, of course, what caused a sharp dip to occur November/December each year for several years on the run? The answer to this lies in the bi-annual dip in geomagnetic activity coincident with the solstice, complicated – as always – by the ‘Geomagnetic Rope Theory’.
January 2017 … CD
COSMIC RAYS ARE INTENSIFYING: A neutron monitor at the South Pole is detecting an upswing in cosmic rays penetrating Earth’s atmosphere. Here are the data, courtesy of the University of Delaware’s Bartol Research Institute:
This is a sign of changing times on the sun. The solar cycle is shifting from Solar Maximum to Solar Minimum. As the sun’s magnetic field weakens, cosmic rays are having an easier time penetrating the inner solar system. Earth is in the cross-hairs of these high-energy particles.
Orbital Changes Over Time:
The angle of the Earth’s tilt is relatively stable over long periods of time. However, Earth’s axis does undergo a slight irregular motion known as nutation – a rocking, swaying, or nodding motion (like a gyroscope) – that has a period of 18.6 years. Earth’s axis is also subject to a slight wobble (like a spinning top), which is causing its orientation to change over time.
Known as precession, this process is causing the date of the seasons to slowly change over a 25,800 year cycle. Precession is not only the reason for the difference between a sidereal year and a tropical year, it is also the reason why the seasons will eventually flip. When this happens, summer will occur in the northern hemisphere during December and winter during June.
Precession, along with other orbital factors, is also the reason for what is known as “length-of-day variation”. Essentially, this is a phenomena where the dates of Earth’s perihelion and aphelion (which currently take place on Jan. 3rd and July 4th, respectively) change over time. Both of these motions are caused by the varying attraction of the Sun and the Moon on the Earth’s equatorial region.
Needless to say, Earth’s rotation and orbit around the Sun are not as simple we once thought. During the Scientific Revolution, it was a huge revelation to learn that the Earth was not a fixed point in the Universe, and that the “celestial spheres” were planets like Earth. But even then, astronomers like Copernicus and Galileo still believed that the Earth’s orbit was a perfect circle, and could not imagine that its rotation was subject to imperfections.
It’s only been with time that the true nature of our planet’s inclination and movements have come to be understood, and what we know is that they lead to some serious variations over time – both in the short run (i.e. seasonal change), and in the long term.
“LITTLE ICE AGE THEORY”
By James A. Marusek, Retired U.S. Navy Physicist who is warning us of what is to come.
General Discussion The sun is undergoing a state change. It is possible that we may be at the cusp of the next Little Ice Age. For several centuries the relationship between periods of quiet sun and a prolonged brutal cold climate on Earth (referred to as Little Ice Ages) have been recognized. But the exact mechanisms behind this relationship have remained a mystery. We exist in an age of scientific enlightenment, equipped with modern tools to measure subtle changes with great precision. Therefore it is important to try and come to grips with these natural climatic drivers and mold the evolution of theories that describe the mechanisms behind Little Ice Ages.
The sun changes over time. There are decadal periods when the sun is very active magnetically, producing many sunspots. These periods are referred to as Solar Grand Maxima. And then there are periods when the sun is very weak producing few sunspot. These periods are called Solar Grand Minima. Solar Grand Minima correspond to dark cold glooming periods called Little Ice Ages. And there are states in-between. During most of the 20th century, the sun was in a Solar Grand Maxima. But that came to an abrupt end beginning in July 2000. The sun produced 6 massive explosions in rapid succession. Each of these explosions produced solar proton events with a proton flux greater than 10,000 pfu @ >10 MeV. These occurred in July 2000, November 2000, September 2001, two in November 2001, and a final one in October 2003. And there hasn’t been any of this magnitude since. Then the sun produced one of the weakest solar minimums since the Ap Index was first recorded (beginning in 1932). The current solar cycle (Solar Cycle 24) is very weak. Not quite weak enough to be called a Solar Grand Minima but very close. It is analogous to a period referred to as a ‘Dalton Minimum’.
As we transitioned from a Grand Solar Maxima, which typified the 20th century to a magnetically quiet solar period similar to a Dalton Minimum (~1798-1823 A.D.), it gave us the opportunity to observe the changes in solar parameters across this transition.
Little Ice Age conditions are defined not only by colder temperatures but also by a shift in the patterns of wind streams. They produce long-lasting locked wind stream patterns responsible for great floods and great droughts. They also affect the cycle of seasons producing great irregularity and crop failures. Altered wind streams impacts the development of massive storms and hurricanes. These Little Ice Age conditions in the past caused poor crop yields, famines, major epidemics, mass migration, war, and major political upheavals.
Read the full document HERE: Little_Ice_Age_Theory
Astronomers Might Have Just Solved a Key Mystery About the Origin of Life
If a massive solar storm struck the Earth today, it could wipe out our technology and hurl us back to the dark ages. Lucky for us, events like this are quite rare. But four billion years ago, extreme space weather was probably the norm. And rather than bringing the apocalypse, it might have kick started life.
That’s the startling conclusion of research published in Nature Geoscience today, which builds on an earlier discovery about young, sun-like stars made with NASA’s Kepler Space Telescope. Baby suns, it turns out, are extremely eruptive, releasing mind-boggling amounts of energy during “solar super flares” that make our wildest space weather look like drizzle.
Now, NASA’s Vladimir Airapetian has shown that if our sun was equally active 4 billion years ago, it could have made the Earth more habitable. According to Airapetian’s models, as solar super flares pounded our atmosphere, they initiated chemical reactions that yielded climate-warming greenhouse gases and other essential ingredients for life.
“The Earth should have been in a deep freeze four billion years ago,” Airapetian told Gizmodo, referring to the “faint young sun paradox” first raised by Carl Sagan and George Mullen in 1972. The paradox came about when Sagan and Mullen realized that Earth had signs of liquid water as early as 4 billion years ago, while the sun was only 70 percent as bright as it is today. “The only way [to explain this] is to somehow incorporate a greenhouse effect,” Airapetian said.
Another early Earth puzzle is how the first biological molecules—DNA, RNA and proteins—scavenged enough nitrogen in order to form. Similar to today, the ancient Earth’s atmosphere was composed primarily of inert nitrogen gas (N2). While specialized bacteria called “nitrogen fixers” eventually figured out how to break N2 and turn it into ammonia (NH4), early biology lacked this ability.
…………………….(see full article)
Maddie is a staff writer at Gizmodo
EARTH’S MAGNETIC FIELD IS CHANGING: Anyone watching a compass needle point steadily north might suppose that Earth’s magnetic field is a constant. It’s not. Researchers have long known that changes are afoot. The north magnetic pole routinely moves, as much as 40 km/yr, causing compass needles to drift over time. Moreover, the global magnetic field has weakened 10% since the 19th century.
A new study by the European Space Agency’s constellation of Swarm satellites reveals that changes may be happening even faster than previously thought. In this map, blue depicts where Earth’s magnetic field is weak and red shows regions where it is strong:
Data from Swarm, combined with observations from the CHAMP and Ørsted satellites, show clearly that the field has weakened by about 3.5% at high latitudes over North America, while it has strengthened about 2% over Asia. The region where the field is at its weakest – the South Atlantic Anomaly – has moved steadily westward and weakened further by about 2%. These changes have occured over the relatively brief period between 1999 and mid-2016.
Earth’s magnetic field protects us from solar storms and cosmic rays. Less magnetism means more radiation can penetrate our planet’s atmosphere. Indeed, high altitude balloons launched by Spaceweather.com routinely detect increasing levels of cosmic rays over California. Perhaps the ebbing magnetic field over North America contributes to that trend.
As remarkable as these changes sound, they’re mild compared to what Earth’s magnetic field has done in the past. Sometimes the field completely flips, with north and the south poles swapping places. Such reversals, recorded in the magnetism of ancient rocks, are unpredictable. They come at irregular intervals averaging about 300,000 years; the last one was 780,000 years ago. Are we overdue for another? No one knows.
Swarm is a trio of satellites equipped with vector magnetometers capable of sensing Earth’s magnetic field all the way from orbital altitudes down to the edge of our planet’s core. The constellation is expected to continue operations at least until 2017, and possibly beyond, so stay tuned for updates.
SOLAR CYCLE CRASHING: Anyone wondering why the sun has been so quiet lately? The reason why is shown in the graph below. The 11-year sunspot cycle is crashing:
For the past two years, the sunspot number has been dropping as the sun transitions from Solar Max to Solar Min. Fewer sunspots means there are fewer solar flares and coronal mass ejections (CMEs). As the explosions subside, we deem the sun “quiet.”
But how quiet is it, really? A widely-held misconception is that space weather stalls and becomes uninteresting during periods of low sunspot number. In fact, by turning the solar cycle sideways, we see that Solar Minimum brings many interesting changes. For instance, the upper atmosphere of Earth collapses, allowing space junk to accumulate around our planet. The heliosphere shrinks, bringing interstellar space closer to Earth. And galactic cosmic rays penetrate the inner solar system with relative ease. Indeed, a cosmic ray surge is already underway. (Goodbye sunspots, hello cosmic rays!)
Stay tuned for updates as the sunspot number continues to drop. | <urn:uuid:9446fe9a-bb34-4153-9f42-e7c69aceaf1c> | 3.65625 | 4,700 | Content Listing | Science & Tech. | 46.321144 | 95,644,054 |
The 5-metre great white, its fin clear to see, repeatedly weaved from side to side as the researchers watched it in awe.
“We saw a black fin and straight away could see it was a very big shark,” cameraman Fernando Lopez-Mirones told El Pais.
“The conditions in the sea were amazing and we had the specimen around three metres from the boat, and we could watch it up close for 70 minutes.”
The Spanish scientists, who were researching marine life in the area, said first sighting in more than three decades of a great white was “historic”.
Although the sharks are native to the Mediterranean, they are normally associated with the oceans off South Africa, Australia and the US.
The first officially recorded sighting in the Mediterranean for at least 30 years excited the research team because the creatures – which can bite humans who get too close – are officially at risk of extinction.
From the 1920s to the 1970s, 27 great whites were captured in the region, according to a 2003 scientific report, but numbers are thought to have plummeted since, because of overfishing, accidental trapping in discarded nets and demand for shark fin soup in the far East.
Mr Lopez-Mirones and colleagues on board an expedition off the Balearics – including Briton Georgina Stevens – are researching the effects of microplastics pollution, among other things. | <urn:uuid:80bd86c1-9321-4ed6-b714-bd63db1b5363> | 3.34375 | 293 | Truncated | Science & Tech. | 40.512789 | 95,644,064 |
STEREO is scheduled to launch from Cape Canaveral Air Force Station, Fla. on the evening of Wednesday, October 25 aboard a Delta II rocket. The launch window extends from 8:38 - 8:53 p.m. EDT.
The mission is comprised of two nearly identical spacecraft the size of golf carts. Their observations will enable scientists to construct the first-ever three-dimensional views of the sun. These images will show the sun's stormy environment and its effect on the inner solar system. The data are vital for understanding how the sun creates space weather.
During the two-year mission, the two spacecraft will explore the origin, evolution and interplanetary consequences of coronal mass ejections, some of the most violent explosions in our solar system. When directed at Earth, these billion-ton eruptions can produce spectacular aurora and disrupt satellites, radio communications and power systems. Energetic particles associated with these solar eruptions permeate the entire solar system and may be hazardous to spacecraft and astronauts.
The UNH component of the mission is called the PLAsma and Supra-Thermal Ion Composition (PLASTIC) investigation and will provide plasma characteristics of protons, alpha particles and heavy ions. Solar wind protons and alpha particles constitute most of the mass in the solar wind and are therefore the primary components exerting kinetic pressure on the Earth’s magnetosphere – one of the drivers for space weather.
PLASTIC is the primary sensor on STEREO for studying coronal-solar wind and solar wind-heliospheric processes. The PLASTIC investigation is an international collaborative effort by the UNH (lead institution), the University of Bern, the University of Kiel, the Max Planck Institute for Extraterrestrial Physics, and NASA Goddard Space Flight Center.
UNH’s lead scientist for PLASTIC is associate research professor Antionette “Toni” Galvin. “The NASA STEREO mission, for the first time, will routinely take images of the extended solar atmosphere with remote imaging instruments on one STEREO spacecraft, while taking direct samples of the same solar wind parcel as it flows by the other STEREO spacecraft,” Galvin said. “STEREO is opening a new era in our understanding of the sun and its influence on the Earth.”
The solar wind is a continuous stream of charged particles that come from the sun and carry its extended atmosphere and magnetic field. Traveling at more than a million miles per hour, the solar wind fills interplanetary space and creates space weather. The composition of the solar wind provides a means of identifying and characterizing the source regions on the sun that are emitting these particles – a process that is essential in the forecasting of certain types of space weather.
"In terms of space-weather forecasting, we're where weather forecasters were in the 1950s," said Michael Kaiser, STEREO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "They didn't see hurricanes until the rain clouds were right above them. In our case, we can see storms leaving the sun, but we have to make guesses and use models to figure out if and when they will impact Earth."
To obtain their unique stereo view of the sun, the two observatories must be placed in different orbits, where they are offset from each other and Earth. Spacecraft "A" will be in an orbit moving ahead of Earth, and "B" will lag behind, as the planet orbits the sun.
Just as the slight offset between eyes provides depth perception, this placement will allow the STEREO observatories to obtain 3-D images of the sun. The arrangement also allows the spacecraft to take local particle and magnetic field measurements of the solar wind as it flows by the spacecraft.
STEREO is the first NASA mission to use separate lunar swingbys to place two observatories into vastly different orbits around the sun. The observatories will fly in “phasing” orbits from a point close to Earth to one that extends just beyond the moon.
Approximately two months after launch, mission operations personnel at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., will use a close flyby of the moon to modify the orbits. The moon's gravity will be used to direct one observatory to its position trailing Earth. Approximately one month later, the second observatory will be redirected after another lunar swingby to its position ahead of Earth. These maneuvers will enable the spacecraft to take permanent orbits around the sun.
Each STEREO spacecraft has four scientific investigations, one of which is PLASTIC. The observatories have imaging telescopes and equipment to measure solar wind particles and to perform radio astronomy.
"STEREO is charting new territory for science research and the building of spacecraft. The simultaneous assembly, integration and launch of nearly identical observatories have been an extraordinary challenge," said Nick Chrissotimos, STEREO project manager at Goddard.
The STEREO mission is managed by Goddard. The Applied Physics Laboratory designed and built the spacecraft. The laboratory will maintain command and control of the observatories throughout the mission, while NASA tracks and receives the data, determines the orbit of the satellites, and coordinates the science results.
“We look forward to a wonderfully productive STEREO mission in which students at UNH will have an opportunity to work at the forefront of solar research,” said Roy Torbert, director of the UNH Space Science Center.
For more information about STEREO and a gallery of images, visit: http://www.nasa.gov/stereo.
Editors and reporters: Toni Galvin, principal investigator for PLASTIC, and project research scientist Mark Popecki can be reached directly via the following means: Galvin: cell phone – (603)-661-9212; E-mail - firstname.lastname@example.org; office – (603) 862-3511 or -0022 (secretary); Popecki: cell phone – (603) 767- 4464; E-mail –email@example.com; office – (603) 862-2957.
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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The Comal Springs dryopid beetle was first discovered in 1987 and only recently described as a species in 1992. It is the only known subterranean aquatic member of the beetle family. Its eyes
are non-functional and its skin is thin, translucent, and weakly pigmented. Adults reach only 0.12 inches long, and females are larger than males.
This species can only be found in the flowing and uncontaminated waters of the Comal and San Marcos Springs in Hays County, Texas. Although it is an aquatic insect, it does not swim, and diet probably consists of other aquatic invertebrates. It is believed that its primary habitat zone is permanently dark. Little is known about the reproductive behavior of this species.
This species is threatened due to its limited range, and a decrease in water quantity and quality and pollution due to human activities may threaten its survival. Conservation plans include monitoring of the species and its habitat, and the continued study of its biology and habitat needs.
Comal Springs Dryopid Beetle Facts Last Updated: April 29, 2017
To Cite This Page:
Glenn, C. R. 2006. "Earth's Endangered Creatures - Comal Springs Dryopid Beetle Facts" (Online).
Accessed 7/23/2018 at http://earthsendangered.com/profile.asp?sp=544&ID=9.
Need more Comal Springs Dryopid Beetle facts?
Ten Creatures that may become extinct in the next 10 years
1. Leatherback Sea Turtle Leatherback sea turtles have been around since pre-historic times. And unfortunately, if the species is allowed to vanish, scientists believe it will foreshadow the extinction of a host of other marine species. It is estimated that there are less than 5,000 nesting female leatherback sea turtles in the Pacific Ocean today, down from 91,000 in 1980. | <urn:uuid:f8412f30-8347-4bd9-a657-bf1859200362> | 3.84375 | 386 | Knowledge Article | Science & Tech. | 56.584899 | 95,644,095 |
Plant populations migrating in response to climate change will have to colonize established communities. Even if a population disperses to a new region with a favorable climate, interactions with other species may prevent its establishment and further spread. The potential of these species to grow along with residents will be a critical factor controlling their response to climate change. To determine the capacity of migrating species to colonize established communities we conducted extensive long-term transplant experiments where potential tree migrant species, i.e. species within `migration range,' were planted side by side with resident ones. Potential immigrants were selected to be representative species of their native communities. For both groups, residents and potential migrants (17 species), we compared their growth response along gradients in soil moisture and light availability. Rather than manipulate climate directly, we exploited natural microclimatic gradients and the fluctuations in climate that occurred during the 5-year experiment. Experimental results were used to estimate growth in the context of novel climate and relevant establishment factors. Results suggest that potential immigrant species had similar growth rates in the new environment than those from resident species ensuring their ability to establish in the area. However, contrary to our expectations, the soil moisture requirements for the immigrant group were similar to those of the resident species. These results could have major implications for vegetation changes under the predicted drier climate for the region. If it is the case that neither resident species nor potential migrants are able to maintain stable populations, the region may experience a decline in local biodiversity.
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Equilibrium is the condition of a system in which competing influences are balanced. In the experiment we measured and experimented for the equilibrant force, conditions and center of gravity. Our results showed consideration as to disregarding other forces than weight and tension.
Equilibrium is a state of balance in which it is a condition where there is no change in the state of motion of a body. Equilibrium may be observed on objects which are at rest and also to objects which are moving at a constant velocity. Two conditions for equilibrium are that the net force acting on the object is zero, and the net torque acting on the object is zero. In the experiment done, conditions for equilibrium are observed. Equilibrant forces were determined using the force table and component methods. The unknown forces were also determined using the first and second conditions for equilibrium. Another part of the experiment was to locate the center of gravity of a composite body and to determine rotational equilibrium.
An object at equilibrium has none influences to cause it to move, either in translation or rotation. The basic conditions for equilibrium are: The conditions for equilibrium are basic to the design of any load-bearing structure such as a bridge or a building since such structures must be able to maintain equilibrium under load. They are also important for the study of machines, since one must first establish equilibrium and then apply extra force or torque to produce the desired movement of the machine
In the first activity, formulas used were:
Ta= (Pan A +added weight)9.8 m/s2
Tb = (Pan B + added weight)9.8m/s2
To get the Experimental Equilibrant we used the weight of the pan A plus the weight added to it.
% Error =|(Exp. – Theoretical)|*100%
In computing the Experimental Equilibrant for the second activity we used ∑F=0
On the third activity, to get the x-coordinate and y-coordinate we used these formulas:
On activity 4, we used these formulas:
-T1(lo/2) + Wc(lo/2 - .05) + T2(lo/2) = 0
(T1 is the reading of spring scale, lo isthe length of bar, Wc=weight of cylinder.)
Materials used were force table, force board, cylinder, spring scale, electronic gram balance, card board, aluminum bar, and protractor. In the first activity: We first weighed three pans then labeled it as A, B and C. Then we hanged each of the in the force table. We then placed 100 g on pan A and 150g on pan B. We then record Ta and Tb. We balanced two tensions in the string. We then recorded magnitude and position of equilibrant and solved for the theoretical equilibrant then computed for the percent error. In the second activity: We used force board and suspended cylinder by means of two strings. We attached a spring scale to one of the strings then recorded the reading. We measure the angle on the other string using a protractor. We weighed the cylinder for the accepted value and computed for the % error. In the third activity: We used the prepared 10cm diameter square and circle. We weighed it separately and the one with the both shapes. Re determined the center of gravity using the balancing method and plumb line method. We specified position of center of gravity the checked results using the formulas given. In the last activity: We located center of gravity of the bar, hanged the cylinder 5.0 cm from the end of the bar. We drew free body diagram then used the second condition for equilibrium in determining the weight of the bar. We weighed the bar using the electronic gram balance and then computed for the % error.
4. Results and Discussion
Table 1: Equilibrant Force
Position ( º)
The table above shows the results for the equilibrant force,...
References: Serway R., Vuille C., Physics Fundamentals 1., CENGAGE Learning, C&E Publishing, Inc.
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Community composition and food web structure of soil decomposer biota in relation to various habitat properties were compared between upper parts of red wood ant (Formica aquilonia) nest mounds and the adjacent forest soil. For a description of trophic structure of the decomposer community in the two habitats, soil decomposers were classified into 14 trophic groups. Classification of the taxa into three habitat preference categories resulted in a clear division of the fauna into either soil or nest specialists, relatively few taxa falling between these two groups. A large majority of the nest specialists belonged to a non-myrmecophilous soil decomposer fauna so far largely overlooked in studies on ant-invertebrate associations. Trophic organisation of the nest mound community differed clearly from that in the soil by having considerably larger biomass at the base of the food web, and less large predators - other than ants - at the top of the web. Contrary to forest soils, the clear dominance of bacterial feeding microfauna over the fungal feeding microfauna in the nest mounds suggests that most of the energy passing through the food web is channelled through a bacterial-based food-web compartment in the nest mounds. Relatively constant temperature and moisture in the nest surface, continuous energy input by the ants to the nests, and ant-induced reduction in predation pressure on macropredators are suggested to be responsible for the development of the typical decomposer community structure in the nest mounds. Thus, the food-web dynamics in ant nest mounds represent an interesting case in which the behaviour of an invertebrate species (i.e. the ant) has a potential to control the development of a system-level organisation. The high biomass of microbi-detritivorous animals, espe- cially earthworms, in the nest mounds suggests that the activities of the decomposer fauna may feed back to the structure of nest mound and indirectly alter the performance of the ant colony. J.
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Dr George Chen received the prestigious award at a ceremony in London to recognise scientists who are helping to put the UK at the forefront of the battle against global warming.
His pioneering work, which is developing ways of taking carbon dioxide (CO2) out of the atmosphere, could play a key role in future efforts to reduce global climate change. His research could also reduce the need to store highly pressurised CO2 underground.
Carbon abatement technologies, including carbon capture, storage and long-term utilisation of CO2, will play a vital role in revolutionising energy use worldwide. The University of Nottingham has a broad range of internationally-recognised research programmes in this field, and launched the Energy Technologies Research Institute in November 2006 to bring together top academics and industrial partners.
The award made to Dr Chen was part of the Royal Society’s ‘Labs to Riches’ event, which encourages innovation in science and technology and promotes its commercial application.
Dr Chen, of The University of Nottingham’s School of Chemical, Environmental and Mining Engineering, said: “It is a great honour for me to receive this prestigious award from the Royal Society.
“I see this award as an authoritative recognition of our research in CO2 mitigation. It has certainly stimulated my whole research group at Nottingham and we are really looking forward to demonstrating the feasibility of this approach.”
The awards were made at a gala dinner at the Royal Society’s headquarters in London on February 15, presented by Sir David Wallace, Vice President and Treasurer of the Royal Society.
Dr Chen won the Brian Mercer Award for Feasibility, which is given to allow researchers to investigate the technical and economic feasibility of commercialising an aspect of their scientific research. The awards were established by a generous bequest from the late Brian Mercer OBE FRS.
The accumulation in the Earth’s atmosphere of ‘greenhouse gases’ such as CO2 is widely blamed for global warming. Greenhouse gases, generated by the burning of fossil fuels and other human activities, are so-called because they trap more of the Sun’s heat — leading to the temperature increases associated with climate change.
Martin Rees, President of the Royal Society, said: “Tackling global warming is not only a moral imperative but it is also an economic one.
“Britain has some of the best scientists in the world and we need to make the most of them. All of the award winners have the potential to change how we live and to make a serious contribution to the UK’s economy.”
The Royal Society is an independent academy promoting the natural and applied sciences. Founded in 1660, its objectives are to strengthen UK science by providing support to excellent individuals, and to fund excellent research that pushes back the frontiers of knowledge.
Other winners of this year’s awards include UK scientists developing research into more efficient solar energy production, and a team looking at a removal and recycling system which consumes less than five per cent of conventional processes.
Tim Utton | alfa
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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Estimating Distribution Parameters and Quantiles
In Chapter 2 we discussed the ideas of a population and a sample. Chapter 4 described probability distributions, which are used to model populations. Based on using the graphical tools discussed in Chapter 3 to look at your data, and based on your knowledge of the mechanism producing the data, you can model the data from your sampling program as having come from a particular kind of probability distribution. Once you decide on what probability distribution to use (if any), you usually need to estimate the parameters associated with that distribution. For example, you may need to compare the mean or 95th percentile of the concentration of a chemical in soil, groundwater, surface water, or air with some fixed standard. This chapter discusses the menu items and functions available in EnvironmentalStats for S-Plus for estimating distribution parameters and quantiles for various probability distributions (as well as constructing confidence intervals for these quantities). See Chapter 5 of Millard and Neerchal (2001) for a more in-depth discussion of this topic.
KeywordsConfidence Limit Data Frame Estimate Quantile Menu Item Lower Confidence Limit
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Yet while the southern Greenland ice cap has been melting, it is still not clear how much this is contributing to rising sea levels, and much further research is needed. A framework for such research was defined at a recent workshop organised by the European Science Foundation (ESF).
"The main objectives were to establish current understanding, prioritise research needs, and develop proposals," said one of the ESF workshop's convenors, Professor Tavi Murray from the Glaciology Group at Swansea University in the UK. "I believe we did the first two very well and laid the ground for developing research proposals."
While recent observations indicate that the Greenland ice cap is melting fast, it is uncertain how much this is contributing to sea levels, as co-convenor Carl Bøggild, from UNIS in Svalbard explained. "A major challenge is to determine what fraction of melt water really runs off, because in many places the melt water will just drain into the cold snow and refreeze," said Bøggild.
One way to determine how much water is running off is to measure not just the area of the Greenland ice cap but also its thickness, but this is much more difficult. Alternatively, the run off process can be tracked both on the ground and by satellite, preferably integrating the two, as was discussed at the workshop. The need to establish a database of ground based observations, including run off, as well as the ongoing calving of ice bergs from the ice cap and occasional events such as earthquakes beneath the ice was discussed.
Perhaps the greatest immediate challenge identified at the workshop though lies in reducing the high levels of uncertainty over the current and future behaviour of the Greenland ice cap, and reconciling the many conflicting observations and predictions. In the case of the meltwater, estimates of the annual total vary by a factor of five from 50 gigatons (GT) to around 250 GT, and this level of uncertainty makes future predictions almost meaningless.
"Laser satellites can detect elevation changes within 10 cm accuracy - but do not consider compaction of the snow," said Murray. "Other satellites using radio waves have a problem with penetration of the signal into the snow. And, yet another method from satellites, measuring the 'weight' of the ice sheet covers too large areas - so you also detect weight changes outside the ice sheet." But at least these multiple sources of data have the potential of being combined to yield more accurate estimates.
Not surprisingly, given these uncertainties, it is unclear even what the immediate future holds for the Greenland ice cap. As Murray noted, recent high levels of thinning in the south and around the edges have taken climatologists by surprise, but there is no guarantee it will continue. "There is much uncertainty presently, because observations of thinning have come as a surprise," said Murray. "We can basically say that three scenarios are possible regarding the enhanced thinning which has been observed recently. One is that it will keep escalating. Secondly it may remain constant even though the climate gets warmer, and thirdly the enhanced rate of thinning may stop altogether, with future thinning being purely the result of melting."
It is not clear yet which of these scenarios will transpire, but Murray and Bøggild are convinced that the ESF workshop has prepared the ground for substantial progress, by bringing together the relevant diverse skills in glaciology, climatology, geology, modelling and satellite imaging. The workshop, Sea-Level Rise From The Greenland Ice Sheet, was held in Mallorca, Spain in May 2008.
Thomas Lau | 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....
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posted by peter
Research the sea lamprey, an exotic species that has had a great impact on the fish communities of the Great
a) Describe the niche of the sea lamprey.
b) Find out how sea lampreys may have entered the Great Lakes ecosystem.
c) Identify the interspecific interactions of the sea lamprey and its effects on the Great Lakes.
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1286 days since this post was last revised. Specific details are likely out of date.
This post serves as a detailed reference and rationale of how to name HTML classes and equivalent CSS selectors using a ECSS methodology.
- ECSS website
- Enduring CSS: writing style sheets for rapidly changing, long-lived projects
- OOCSS/Atomic CSS are Responsive Web Design ‘anti-patterns’
Here is the format for writing ECSS classes/selectors:
To illustrate the separate sections, here is the anatomy of that selector with the sections delineated with square brackets:
/\.(\w*)+\-+(([A-Z][a-z]+)+$)/gcould be used to parse class names and ensure adherence to the required sections of a ECSS style selector.
- namespace : all lowercase/train-case. Usually an abbreviation (required).
- ComponentName : upper camel case/pascal case (required)
- _ComponentSection : upper camel case/pascal case preceded by an underscore (optional)
- -variant-flag : all lowercase/train-case (optional)
Each part of a class name can be logically discerned from another. More information on what these sections are and how they should be employed follows:
The first part of a HTML class/CSS selector is a namespace (all lowercase/train-case). The namespace is used to prevent collisions and provide some soft isolation for easier maintenance. More on that rationale here: http://benfrain.com/enduring-css-writing-style-sheets-rapidly-changing-long-lived-projects/
The principle types of namespaces employed are:
- namespace a component, visual area or feature
- namespace a state
Most namespaces are abbreviations, for example:
.sc-could be ‘Shopping Cart’
.asc-could be for ‘Aside Callout’
.ocn-could be for ‘Off Canvas Navigation’
Component/feature/visual area namespace
Any component should be namespaced for easy maintenance and to provide soft isolation from other components. Anything that is different from something else, regardless of the subtleties should be namespaced into its own component.
A State namespace is used to communicate a change in ‘state’. For example:
Indicates that on, or somewhere below this node, the ‘Mini Cart’ is active.
This would communicate that the Component or one within it is showing some value (that was previously hidden).
The final use of the namespace section is to communicate a hook for dynamic JS. For example:
Note: CSS authors should not remove
js- namespaced Components or classes without checking potential impact on the JS.
The Component Name is main name of ‘the thing’. For example:
Would be an ‘Item’ within the ‘sc’ (shopping cart in this example) namespace. It usually doesn’t exist on its own (unless the component has no individual sections).
If something UpperCamelCase is preceded by an underscore it is a ComponentSection (if not it is a ComponentName).
_Wrapper is indicating that this node is the ‘Wrapper’ section of the ‘Item’ that is part of the ‘sc’ namespace
If something is all lowercase/train-case and not the first part of a class name it is a variant flag.
-warning flag indicates that this
.sc-Item_Wrapper is a warning version (and may subsequently be subtly different.)
The only exception to these rules are ‘Utility’ classes. If a class is lowercase, all by itself, then it is a utility class. These classes are used for one specific job.
This is a utility class for adding 100% width to a node.
Note: the use of utility classes is discouraged as it then ties markup to a visual pattern that may not be suitable at all viewports. | <urn:uuid:75780e87-6493-4cce-bb2f-d8ad6dc88fe7> | 2.875 | 851 | Personal Blog | Software Dev. | 38.049924 | 95,644,199 |
When you are going to do exact mathematical computations for the
discrete space-time, then the continuous mathematics is not enough,
because then you will only get an approximation of the reality. So
there is a need for developing a special calculus for a discrete
One difference between continuous and discrete mathematics is the rule
for how to derívate the product of two functions. In continuous
mathematics the rule says:
D(f*g) = f*D(g) + D(f)*g.
But in the discrete mathematics the corresponding rule says:
D(f*g) = f*D(g) + D(f)*g + D(f)*D(g).
In discrete mathematics you have difference equations of type: x(n+2) =
x(n+1) + x(1), x(0) = 0, x(1) = 1, which then will give the number
sequence 0,1,1,2,3,5,8,13,21,34,55,... etc. For a general difference
equation you have:
Sum(a(i)*x(n+i)) = 0, plus a number of starting conditions.
If you then introduce the step operator S with the effect: S(x(n)) =
x(n+1), then you can express the difference equation as:
Sum((a(i)*S^i)(x(n)) = 0.
You will then get a polynom in S. If the roots (the eigenvalues) to
this polynom are e(i), you will then get:
Sum(a(i)*S^i) = Prod(S - e(i)) = 0.
This will give you the equations S - e(i) = 0, or more complete: (S -
e(i))(x(n)) = S(x(n)) - e(i)*x(n) = x(n+1) - e(i)*x(n) = 0, which have
the solutions x(n) = x(0)*e(i)^n.
The general solution to this difference equation will then be a linear
combination of these solutions, such as:
x(n) = Sum(k(i)*e(i)^n), where k(i) are arbitrary constants.
To get the integer solutions you can then build the eigenfunctions:
x(j,n) = Sum(k(i,j)*e(i)^n) = delta(j,n), for n < the grade of the
With the S-operator it is then very easy to define the difference- or
derivation-operator D as:
D = S-1, so D(x(n)) = x(n+1) - x(n).
What do you think, is this a good starting point for handling the
mathematics of the discrete space-time?
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Demographic importance of ecological interactions: how much do statistics tell us?
- 70 Downloads
Many investigators demonstrate the existence of intra- and interspecific interactions through rigorous statistical hypothesis testing. Statistical significance of an interaction, however, does not necessarily imply that it controls a species population size or distribution. Other analytical methods must be used to make these important determinations. This paper demonstrates one method, with an example, to quantify the demographic importance of statistically significant interactions. In our example, some of the statistically significant interactions with the polychaete Clymenella torquata (Leidy) have large impacts on the population growth rate of the bivalve Gemma gemma (Totten), while others do not. This demonstrates the necessity of distinguishing between statistical significance and demographic importance. In some cases, the demographic importance of the same interaction changes through time because of changes in the bivalve's life history. Interactions affecting juvenile bivalves often have a greater demographic importance than those affecting adults; but this is not always the case.
KeywordsGrowth Rate Population Size Significant Interaction Life History Population Growth
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Today we have been exploring forces. We looked at pushing and pulling and sorted some objects into things we push and things we pull.
We also looked at different ways to make cars travel further. We changed the surface and the height of the ramp.
Look at our pictures showing us investigating!
What happened when we changed the height of the ramp? What about the surface? Which was the best surface to make the car travel further? | <urn:uuid:455d8ef2-a847-4452-8965-2e5485f8e2cd> | 3.21875 | 88 | Personal Blog | Science & Tech. | 68.517573 | 95,644,263 |
1124 GMT July 21, 2018
The iceberg towers over houses on a promontory in the village of Innaarsuit but it is grounded and has not moved overnight, local media KNR reported.
A danger zone close to the coast has been evacuated and people have been moved further up a steep slope where the settlement lies, a Greenland police spokesman told Reuters.
Another large iceberg with width of six kilometers (four miles) has broken off from a glacier in eastern Greenland and scientists have captured the dramatic event on video.
New York University Professor David Holland, an expert in atmospheric and ocean science, told The Associated Press, “This is the largest event we’ve seen in over a decade in Greenland.”
A June 22 video of the incident was taken by his wife, Denise Holland of NYU's Environmental Fluid Dynamics Laboratory. They had camped by the Helheim Glacier for weeks to collect data to better project sea level changes due to global warming, AP reported.
This phenomenon, called calving, is a direct outcome of global warming, which some world leaders are in denial of.
The event began on June 22 and took place over approximately 30 minutes. According to a press release by the New York University (NYU), the resulting iceberg, which broke off from Greenland’s Helheim Glacier, would stretch from lower Manhattan up to midtown New York City – about six kilometers.
Holland, the logistics coordinator for NYU’s Environmental Fluid Dynamics Laboratory and NYU Abu Dhabi’s Center for Global Sea Level Change said, “The better we understand what’s going on means we can create more accurate simulations to help predict and plan for climate change.”
He said Wednesday that the time-lapse video, which is speeded up 20 times, shows “three percent of the annual ice loss of Greenland occurs in 30 minutes.”
“It sounded like rockets going off,” he said, describing it as “a very complex, chaotic, noisy event.”
While the couple is studying Greenland, he said that “The real concern is in Antarctica, where everything is so big the stakes are much higher.” | <urn:uuid:1ec4d4f8-38e1-4593-b13a-bffb0c1a552b> | 2.625 | 455 | News Article | Science & Tech. | 39.474979 | 95,644,279 |
Washington: Researchers at MIT have determined the size of carbon dioxide snow particles in clouds at both Martian poles from data gathered by orbiting spacecraft.
In the dead of a Martian winter, clouds of snow blanket the Red Planet’s poles — but unlike our water-based snow, the particles on Mars are frozen crystals of carbon dioxide.
Most of the Martian atmosphere is composed of carbon dioxide, and in the winter, the poles get so cold — cold enough to freeze alcohol — that the gas condenses, forming tiny particles of snow.
From their calculations, the group found snow particles in the south are slightly smaller than snow in the north — but particles at both poles are about the size of a red blood cell.
“These are very fine particles, not big flakes,” said Kerri Cahoy, the Boeing Career Development Assistant Professor of Aeronautics and Astronautics at MIT.
If the carbon dioxide particles were eventually to fall and settle on the Martian surface, “you would probably see it as a fog, because they’re so small.”
Cahoy and graduate student Renyu Hu worked with Maria Zuber, the E.A. Griswold Professor of Geophysics at MIT, to analyze vast libraries of data gathered from instruments onboard the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO). From the data, they determined the size of carbon dioxide snow particles in clouds, using measurements of the maximum buildup of surface snow at both poles. The buildup is about 50 percent larger at Mars’ south pole than its north pole.
Over the course of a Martian year (a protracted 687 days, versus Earth’s 365), the researchers observed that as it gets colder and darker from fall to winter, snow clouds expand from the planet’s poles toward its equator. The snow reaches halfway to the equator before shrinking back toward the poles as winter turns to spring, much like on Earth.
To get an accurate picture of carbon dioxide condensation on Mars, Hu analyzed an immense amount of data, including temperature and pressure profiles taken by the MRO every 30 seconds over the course of five Martian years (more than nine years on Earth). The researchers looked through the data to see where and when conditions would allow carbon dioxide cloud particles to form.
The team also sifted through measurements from the MGS’ laser altimeter, which measured the topography of the planet by sending laser pulses to the surface, then timing how long it took for the beams to bounce back. Every once in a while, the instrument picked up a strange signal when the beam bounced back faster than anticipated, reflecting off an anomalously high point above the planet’s surface. Scientists figured these laser beams had encountered clouds in the atmosphere.
Hu analyzed these cloud returns, looking for additional evidence to confirm carbon dioxide condensation. He looked at every case where a cloud was detected, then tried to match the laser altimeter data with concurrent data on local temperature and pressure. In 11 instances, the laser altimeter detected clouds when temperature and pressure conditions were ripe for carbon dioxide to condense. Hu then analyzed the opacity of each cloud — the amount of light reflected — and through calculations, determined the density of carbon dioxide in each cloud.
To estimate the total mass of carbon dioxide snow deposited at both poles, Hu used earlier measurements of seasonal variations in the Martian gravitational field done by Zuber’s group: As snow piles up at Mars’ poles each winter, the planet’s gravitational field changes by a tiny amount.
By analyzing the gravitational difference through the seasons, the researchers determined the total mass of snow at the north and south poles. Using the total mass, Hu figured out the number of snow particles in a given volume of snow cover, and from that, determined the size of the particles. In the north, molecules of condensed carbon dioxide ranged from 8 to 22 microns, while particles in the south were a smaller 4 to 13 microns.
Hu noted that knowing the size of carbon dioxide snow cloud particles on Mars might help researchers understand the properties and behavior of dust in the planet’s atmosphere.
The study was published in the Journal of Geophysical Research, which details the group’s results. | <urn:uuid:4a4af9ff-cee6-474c-812c-38216129f31c> | 3.65625 | 879 | News Article | Science & Tech. | 37.417923 | 95,644,283 |
Tidal choking and bed friction in Negombo Lagoon, Sri Lanka
- Lars Rydberg, Lisa Wickbom
- Estuaries SCOPUS
- Coastal and Estuarine Research Federation in 1996
- Cited Count
- Springer JSTOR
We have studied bed friction and water exchange in a small, almost enclosed, shallow lagoon in Sri Lanka, where both tides and freshwater supply are important for the circulation. Because of the narrow entrance, the lagoon is strongly choked for semidiurnal tidal forcing (the choking coefficient is 0.25). A set of tide gauges positioned on each side of the entrance channel was used to calculate bed friction. Measurements made over three short periods having different freshwater supply to the lagoon indicate an average friction (drag) coefficient CD=0.0041±0.0002 (using a quadratic friction law). A comparison between observed and calculated velocities in the channel for a variety of velocities, indicates that the quadratic friction law is a good tool for parameterization. High freshwater supply increases the lagoonal sea level substantially and decreases the residence time.
If you register references through the customer center, the reference information will be registered as soon as possible. | <urn:uuid:18b70e90-54e4-4e12-b017-1d6b4aed5445> | 2.703125 | 255 | Academic Writing | Science & Tech. | 29.693287 | 95,644,317 |
Ocean acidification is a threat to food security, economies, and culture because of its potential impacts on marine ecosystem services. Information on how ocean acidification will impact ecosystems and the services they provide can help guide how we adapt to and mitigate forecasted changes.
The OAP funds modeling studies to advance our understanding of the impacts of ocean acidification on coastal ecosystems and fisheries.
Scientists can use a wide variety of models to project the potential progression of acidification in different regions, the impacts that changes in chemistry may have on marine life, and how these changes could affect a variety of ecosystem services including fisheries, aquaculture, and protection of coasts by coral reefs. For example, projections of ocean acidification can be incorporated into food-web models to better understand how changing ocean chemistry could affect harvested species, protected species, and the structure of the food web itself. Economic-forecast models can be used to analyze the economic impacts of potential changes in fisheries harvest caused by ocean acidification.
Figure from: Harvey et al. 2010
Experiments on species response suggest that ocean acidification will directly affect a wide variety of organisms from calcifying shellfish and coral to fish and phytoplankton. Ecosystem models can capture the complex effects of ocean acidification on entire ecosystems.
How marine organisms respond to ocean acidification will be influenced by their reaction to chemistry change and their interactions with others species, such as their predators and prey. Scientists use ecosystem models to understand how ocean chemistry may affect entire ecosystems because they account for the complex interactions between organisms. Output from such modeling exercises can inform management of fisheries, protected species, and other important natural resources. Because ecosystem feedbacks are complex, understanding the uncertainty associated with these models is critical to effective management.
Projections of the economic impacts of ocean acidification can be created by combining economic models with findings from laboratory experiments and ecological models.
For example, these links can be made for port communities or specific fisheries through modeling changes in fish harvest. Researchers at the Alaska Fisheries Science Center have developed bio-economic forecasts for the economically and culturally important species red king crab. Researchers at the Northwest Fisheries Science Center are developing projections of how the economies of regional port communities might be altered by potential changes in West Coast fisheries caused by ocean acidification.
The NOAA Ocean Acidification Program (OAP) is working to build knowledge about how to adapt to the consequences of ocean acidification (OA) and conserve marine ecosystems as acidification occurs.
Turning current observations into forecasts is the key mechanism by which adaptation plans are created.
Forecasting provides insight into a vision of the future by using models that visualize how quickly and where ocean chemistry will be changing in tandem with an understanding of how sensitive marine resources and communities are to these changes. By making predictions about the future, we can better adapt and prepare for ocean acidification. Coastal forecasts for ocean acidification are currently being developed for the West Coast, Chesapeake Bay, the East Coast, Caribbean and the western Gulf of Mexico. Ocean acidification hotspots are areas that are particularly vulnerable, either from a biological, economic, or cultural perspective. Identification of these hot spots in coastal waters is a priority for the Coastal Acidification Networks (CANs), fostered by the Ocean Acidification Program around the country. These networks bring together scientists, decision makers, fishermen and other stakeholders to identify and answer the most important questions about acidification and its effects in the region.
NOAA scientists have played an important role in development of the J-SCOPE forecast system, used to create seasonal forecasts for the North Pacific region. These forecasts will allow fisheries managers to predict seasonal outlooks for management decisions.
Developing innovative tools to help monitor ocean acidification and mitigate changing ocean chemistry locally
Management strategies use information provided by research and tools that can be used to make sound decisions to effectively conserve marine resources. Baseline research about organism and community sensitivity to ocean acidification is incorporated into these strategies, in an effort to sustain these resources for the future.
Before management plans can be created it is necessary to have baseline research about the effects of ocean acidification on marine resources, such as Pacific oysters, Dungeness crabs and rockfish. The OAP funds NOAA Fisheries Science Centers to expose various life stages of valuable species to present and future acidification conditions. The biological response research is then incorporated into models that can be used to create tools for managers to use so that they can test different scenarios on species’ populations and habitats. Modeling efforts led by Woods Hole Oceanographic Institution are now being used to produce one of these tools for Atlantic sea scallop fisheries. The dashboard will allow managers to test the impacts of different management actions on scallop populations. In the Pacific Northwest, NOAA, the University of Washington, and shellfish industry scientists have formed a strong partnership to adapt to ocean acidification impacts that have already affected the shellfish industry. Together these researchers determined that acidification was threatening oyster production and offered an approach to address it. They installed equipment to monitor carbon chemistry at shellfish hatcheries and worked with hatchery managers to develop methods that protect developing oyster larvae from exposure to low pH waters. Early warning tools are now being used to forecast seasonal acidification conditions to enable shellfish growers to adapt their practices.
This portal provides a real-time data stream of ocean acidification data that can be used by shellfish growers, regional managers, stakeholders and the public. The portal can be used to make resource decisions and build adaptation strategies.
Coastal Maine supports valuable lobster, clam, oyster and other shellfish industries that comprise >90% of Maine’s record $616M landed value last year. Earlier monitoring efforts in Maine and New Hampshire have documented periods of unusually acidic conditions in subsurface waters of Maine’s estuaries, which may be driven by episodic influxes of waters from the Gulf’s nutrient-rich, highly productive coastal current system. Sources of acidity to the estuaries also include the atmosphere, freshwater fluxes, and local eutrophication processes, all modulated by variability imparted by a number of processes.This project is a data synthesis effort to look at long-term trends in water quality data to identify the key drivers of acidification in this area. Extensive data sets dating back to the 1980s (including carbonate system, hydrography, oxygen, nutrients, and other environmental variables) will be assembled, subjected to QA/QC, and analyzed to assess acidification events in the context of landward, seaward and direct atmospheric sources, as may be related to processes operating on tidal to decadal timescales. Such analyses are requisite for any future vulnerability assessments of fishery-dependent communities in Maine and New Hampshire to the effects of coastal acidification.
Ocean acidification (OA) is already harming shellfish species in the Pacific Northwest, a global hotspot of OA. While OA poses a threat to regional communities, economies, and cultures that rely on shellfish, identified gaps remain in adaptive capacity and vulnerability of several stakeholders. This project will address these gaps by extending long-standing collaborative OA vulnerability research with shellfish growers to include other shellfish users (e.g. port towns, Native American tribes and shellfish sector employees). The project includes five objectives: 1) Map variations in shellfisheries’ exposure to OA and identify those that are most sensitive, 2) quantify production losses from OA and costs of investment in adaptation 3) Identify potential pathways for adaptation, 4) identify key technological, institutional, legislative, financial and cultural barriers to OA adaptation, 5) evaluate the cost of potential adaptation strategies, and develop behavioral models to predict the likelihood of users adopting specific adaptation strategies. The research is designed to identify key vulnerabilities, determine the cost of OA to Pacific Northwest shellfish stakeholders, and to model adaptation pathways for maximizing resilience to OA. The adaptation framework developed here will be replicable in other shellfisheries yet to experience OA impacts.
The Olympic Coast, located in the Pacific Northwest U.S., stands as a region already experiencing effects of ocean acidification (OA). This poses risks to marine resources important to the public, especially local Native American tribes who are rooted in this place and depend on marine treaty-protected resources. This project brings together original social science research, synthesis of existing chemical and biological data from open ocean to intertidal areas, and model projections, to assess current and projected Olympic Coast vulnerabilities associated with OA. This critical research aims to increase the tribes’ ability to prepare for and respond to OA through respective community-driven strategies. By constructing a comprehensive, place-based approach to assess OA vulnerability, decision-makers in the Pacific Northwest will be better able to anticipate, evaluate and manage societal risks and impacts of OA. This collaborative project is developed in partnership with tribal co-investigators and regional resource managers from start to finish and is rooted in a focus on local priorities for social, cultural, and ecological health and adaptive capacity.
This project will expand the quantity and quality of ocean acidification (OA) monitoring across Northeastern U.S. coastal waters. The new OA data and incorporation of the world’s first commercial total alkalinity (TA) sensor into our regional observing system (NERACOOS) are designed to supply needed baseline information in support of a healthy and sustainable shellfish industry, and to aid in assessments and projections for wild fisheries. In working with partners to develop this proposal, clear concerns were brought forward regarding the potential impacts of increasing ocean acidity that extend from nearshore hatcheries and aquaculture to broader Gulf of Maine finfish and shellfish industries and their management. Stakeholder input and needs shaped the project scope such that both nearshore and offshore users will be served by TA sensor deployments on partner platforms, including time series data collection at an oyster aquaculture site, on the NOAA Ship of Opportunity AX-2 line, and on federal and State of Maine regional fish trawl surveys. In all, five different deployment platforms will be used to enhance ocean acidification monitoring within the Northeast Coastal Acidification Network (NE-CAN) with significant improvement in temporal and spatial coverage.
Adding the all-new TA measurement capability to the regional observation network will provide more accurate, certain, and reliable OA monitoring, and an important project objective is to demonstrate and relay this information to regional partners. Data products to be developed from the multi-year measurements include nearshore and offshore baseline OA seasonal time series as well as threshold indices tied to acidification impacts on larval production at the Mook Sea Farm oyster hatchery. An outreach and technical supervision component will include the transfer of carbonate system observing technologies to our partners and to the broader fishing industry, resource management, and science communities. NERACOOS will provide data management and communication (DMAC) services and work towards implementing these technological advances into the IOOS network.
Working across four IOOS Regional Associations in partnership with the shellfish industry and other groups affected by ocean acidification (OA), our proposal is divided into four tasks that continue the foundational aspects established to date and expand both technical capacity and the development of new technology with respect to OA observing needs for shellfish growers and other related impacted and potentially vulnerable U.S. industries, governments (tribal, state, local) and other stakeholders. Our proposed work includes development of observing technology, expert oversight intelligence, data dissemination, and outreach and will be executed by a team that includes a sensor technology industry and academic and government scientists. We will: 1) Develop new lower cost and higher accuracy sensor technology for OA monitoring and expand them to new sites; 2) Utilize regional partnerships of users and local experts to implement and provide Quality Assurance/Quality Control (QA/QC) tests of the new OA sensors; 3) Establish data handling and dissemination mechanisms that provide both user-friendly and standards-based web service access that are exportable from the Pacific Coast module to the entirety of U.S. Integrated Ocean Observing System (IOOS); and 4) Provide education and outreach services to stakeholders concerned about and potentially impacted by OA. | <urn:uuid:afbc7a15-7c66-43ba-9d5d-438badf61a19> | 3.671875 | 2,504 | About (Org.) | Science & Tech. | 5.820783 | 95,644,318 |
For example, in places where annual rainfall may increase by 20 percent as a result of climate change, the groundwater might increase as much as 40 percent.
Conversely, the analysis showed in some cases just a 20 percent decrease in rainfall could lead to a 70 percent decrease in the recharging of local aquifers — a potentially devastating blow in semi-arid and arid regions.
But the exact effects depend on a complex mix of factors, the study found — including soil type, vegetation, and the exact timing and duration of rainfall events — so detailed studies will be required for each local region in order to predict the possible range of outcomes.
The research was conducted by Gene-Hua Crystal Ng, now a postdoctoral researcher in MIT's Department of Civil and Environmental Engineering (CEE), along with King Bhumipol Professor Dennis McLaughlin and Bacardi Stockholm Water Foundations Professor Dara Entekhabi, both of CEE, and Bridget Scanlon, a senior researcher at the University of Texas. The results are being presented Wednesday, Dec. 17, at the American Geophysical Union's fall meeting in San Francisco.
The analysis combines computer modeling and natural chloride tracer data to determine how precipitation, soil properties, and vegetation affect the transport of water from the surface to the aquifers below. This analysis focused on a specific semi-arid region near Lubbock, Texas, in the southern High Plains.
Predictions of the kinds and magnitudes of precipitation changes that may occur as the planet warms are included in the reports by the Intergovernmental Panel on Climate Change (IPCC), and are expressed as ranges of possible outcomes. "Because there is so much uncertainty, we wanted to be able to bracket" the expected impact on water supplies under the diverse climate projections, Ng says.
"What we found was very interesting," Ng says. "It looks like the changes in recharge could be even greater than the changes in climate. For a given percentage change in precipitation, we're getting even greater changes in recharge rates."
Among the most important factors, the team found, is the timing and duration of the precipitation. For example, it makes a big difference whether it comes in a few large rainstorms or many smaller ones, and whether most of the rainfall occurs in winter or summer. "Changes in precipitation are often reported as annual changes, but what affects recharge is when the precipitation happens, and how it compares to the growing season," she says.
The team presented the results as a range of probabilities, quantifying as much as possible "what we do and don't know" about the future climate and land-surface conditions, Ng says. "For each prediction of climate change, we get a distribution of possible recharge values."
If most of the rain falls while plants are growing, much of the water may be absorbed by the vegetation and released back into the atmosphere through transpiration, so very little percolates down to the aquifer. Similarly, it makes a big difference whether an overall increase in rainfall comes in the form of harder rainfalls, or more frequent small rainfalls. More frequent small rainstorms may be mostly soaked up by plants, whereas a few more intense events may be more likely to saturate the soil and increase the recharging effect.
"It's tempting to say that a doubling of the precipitation will lead to a doubling of the recharge rate," Ng says, "but when you look at how it's going to impact a given area, it gets more and more complicated. The results were startling."
Elizabeth Thomson | 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
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences | <urn:uuid:b7f8073f-41c4-495b-a12e-4910dad0b56e> | 3.53125 | 1,359 | Content Listing | Science & Tech. | 39.752086 | 95,644,330 |
The dense, iron core forms the center of the Earth. Scientists know that the core is metal. The inner core is solid, and the outer core is molten.
CK-12 (Middle School)
RST.4 - Key Terms, RST.1 - Analysis & Evidence
DEPTH OF KNOWLEDGE (DOK) LEVELS:
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When it comes to global warming, there are seven big contributors: the United States, China, Russia, Brazil, India, Germany and the United Kingdom. A new study published in Environmental Research Letters reveals that these countries were collectively responsible for more than 60 per cent of pre-2005 global warming. Uniquely, it also assigns a temperature change value to each country that reflects its contribution to observed global warming.
The study was conducted at Concordia under the leadership of Damon Matthews, an associate professor in the Department of Geography, Planning and Environment. In a straight ranking, the U.S. is an unambiguous leader, responsible for a global temperature increase of 0.15 C. That’s close to 20 per cent of the observed warming.
China and Russia account for around eight per cent each; Brazil and India seven per cent; and Germany and the U.K. around five per cent each. Canada comes in in 10th place, just after France and Indonesia. Although it may seem surprising that less industrialized countries, including Brazil and Indonesia, ranked so highly, their positions reflect carbon dioxide emissions related to deforestation.
In the study, the research team used a new methodology to calculate national contributions to global warming. It weighted each type of emission according to the atmospheric lifetime of the temperature change it caused. Using data from 1750 onward, the team accounted for carbon dioxide contributions from fossil fuel burning and land-use change, along with methane, nitrous oxide and sulphate aerosol emissions.
Matthews and his colleagues also experimented with scaling the emissions to the size of the corresponding area. Western Europe, the U.S., Japan and India are hugely expanded, reflecting emissions much greater than would be expected based on their geographic area. Russia, China and Brazil stay the same. Taken in this light, the climate contributions of Brazil and China don’t seem so out of line — they are perfectly in proportion with the countries’ landmasses. Of course, Canada and Australia become stick thin, being countries whose geography is much larger than their share of the global warming pie.
Meanwhile, dividing each country’s climate contribution by its population paints a different picture. Amongst the 20 largest total emitters, developed countries occupy the top seven per-capita positions, with Canada falling in third place behind the U.K. and the United States. And in this ranking, China and India drop to the bottom of the list.
Matthews’s study highlights how much individual countries have contributed to the climate problem, as well as the huge disparity between rich and poor with respect to per-person contributions to global warming. Acknowledging these disparities, and then moving to correct them, may be a fundamental requirement for success in efforts to decrease global greenhouse-gas emissions.
NB - Parts of this text appear courtesy of New Scientist magazine.Source
Clea Desjardins | EurekAlert!
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