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What is a Computer Chip?

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Computer chips are one of the basic components of most electronic devices.

A computer chip is a small electronic circuit, also known as an integrated circuit, which is one of the basic components of most kinds of electronic devices, especially computers. Computer chips are small and are made of semiconductors that is usually composed of silicon, on which several tiny components including transistors are embedded and used to transmit electronic data signals. They became popular in the latter half of the 20th century because of their small size, low cost, high performance and ease to produce.

The modern computer chip saw its beginning in the 1950s through two separate researchers who were not working together, but developed similar chips. The first was developed at Texas Instruments by Jack Kilby in 1958, and the second was developed at Fairchild Semiconductor by Robert Noyce in 1958. These first computer chips used relatively few transistors, usually around ten, and were known as small-scale integration chips. As time went on through the century, the amount of transistors that could be attached to the computer chip increased, as did their power, with the development of medium-scale and large-scale integration computer chips. The latter could contain thousands of tiny transistors and led to the first computer microprocessors.

There are several basic classifications of computer chips, including analog, digital and mixed signal varieties. These different classifications of computer chips determine how they transmit signals and handle power. Their size and efficiency are also dependent upon their classification, and the digital computer chip is the smallest, most efficient, most powerful and most widely used, transmitting data signals as a combination of ones and zeros.

Robert Noyce was one of the first developers of the modern computer chip.
Robert Noyce was one of the first developers of the modern computer chip.

Today, large-scale integration chips can actually contain millions of transistors, which is why computers have become smaller and more powerful than ever. Not only this, but computer chips are used in just about every electronic application including home appliances, cell phones, transportation and just about every aspect of modern living. It has been posited that the invention of the computer chip has been one of the most important events in human history. The future of the computer chip will include smaller, faster and even more powerful integrated circuits capable of doing amazing things, even by today’s standards.

Source / Courtesy : WiseGeek

What Is a Transistor?

[dropcap]A[/dropcap] transistor is a semiconductor, differentiated from a vacuum tube primarily by its use of a solid, non-moving part to pass a charge. They are crucial components in virtually every piece of modern electronics, and are considered by many to be the most important invention of the modern age (as well as a herald of the Information Age).

The development of the transistor grew directly out of huge advances in diode technology during World War II. In 1947, scientists at Bell Laboratories unveiled the first functional model after a number of false starts and technological stumbling blocks.

The first important use of the transistor was in hearing aids, by military contractor Raytheon, inventors of the microwave oven and producer of many widely-used missiles, including the Sidewinder and Patriot missiles.

The first transistor radio was released in 1954 by Texas Instruments, and by the beginning of the 1960s, these radios had become a mainstay of the worldwide electronics market. Also in the 1960s, transistors were integrated into silicon chips, laying the groundwork for the technology that would eventually allow personal computers to become a reality. In 1956, Bill Shockley, Walter Brattain, and John Bardee won the Nobel Prize for physics for their development of the transistor.

The first important use of the transistor was in hearing aids.
The first important use of the transistor was in hearing aids.

The primary type currently in use is known as a bipolar junction transistor, which consists of three layers of semi-conductor material, two of which have extra electrons, and one which has gaps in it. The two with extra electrons (N-Type) sandwich the one with gaps (P-Type). This configuration allows the transistor to be a switch, closing and opening rapidly like an electronic gate, allowing voltage to pass at a determined rate. If it is not shielded from light, the light may be used to open or close the gate, in which case it is referred to as a phototransistor, functioning as a highly-sensitive photodiode.

The secondary type is known as a field-effect transistor, and consists either entirely of N-Type semi-conductive material or P-Type semi-conductive material, with the current controlled by the amount of voltage applied to it.

Source / Courtesy : WiseGeek

Imaging electric charge propagating along microbial nanowires

UMass Amherst researchers recently provided stronger evidence than ever before to support their claim that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, along which electric charges propagate just as they do in carbon nanotubes, a highly conductive human-made material. Credit: UMass Amherst
UMass Amherst researchers recently provided stronger evidence than ever before to support their claim that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, along which electric charges propagate just as they do in carbon nanotubes, a highly conductive human-made material.
Credit: UMass Amherst

The claim by microbiologist Derek Lovley and colleagues at the University of Massachusetts Amherst that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, has been mired in controversy for a decade, but the researchers say a new collaborative study provides stronger evidence than ever to support their claims.

UMass Amherst physicists working with Lovley and colleagues report in the current issue of Nature Nanotechnology that they’ve used a new imaging technique, electrostatic force microscopy (EFM), to resolve the biological debate with evidence from physics, showing that electric charges do indeed propagate along microbial nanowires just as they do in carbon nanotubes, a highly conductive human-made material.

Physicists Nikhil Malvankar and Sibel Ebru Yalcin, with physics professor Mark Tuominen, confirmed the discovery using EFM, a technique that can show how electrons move through materials. “When we injected electrons at one spot in the microbial nanowires, the whole filament lit up as the electrons propagated through the nanowire,” says Malvankar.

Yalcin, now at Pacific Northwest National Lab, adds, “This is the same response that you would see in a carbon nanotube or other highly conductive synthetic nanofilaments. Even the charge densities are comparable. This is the first time that EFM has been applied to biological proteins. It offers many new opportunities in biology.”

Lovley says the ability of electric current to flow through microbial nanowires has important environmental and practical implications. “Microbial species electrically communicate through these wires, sharing energy in important processes such as the conversion of wastes to methane gas. The nanowires permit Geobacter to live on iron and other metals in the soil, significantly changing soil chemistry and playing an important role in environmental cleanup. Microbial nanowires are also key components in the ability of Geobacter to produce electricity, a novel capability that is being adapted to engineer microbial sensors and biological computing devices.”

He acknowledges that there has been substantial skepticism that Geobacter’s nanowires, which are protein filaments, could conduct electrons like a wire, a phenomenon known as metallic-like conductivity. “Skepticism is good in science, it makes you work harder to evaluate whether what you are proposing is correct,” Lovley points out. “It’s always easier to understand something if you can see it. Drs. Malvankar and Yalcin came up with a way to visualize charge propagation along the nanowires that is so elegant even a biologist like me can easily grasp the mechanism.”

Biologists have known for years that in biological materials, electrons typically move by hopping along discrete biochemical stepping-stones that can hold the individual electrons. By contrast, electrons in microbial nanowires are delocalized, not associated with just one molecule. This is known as metallic-like conductivity because the electrons are conducted in a manner similar to a copper wire.

Malvankar, who provided the first evidence for the metallic-like conductivity of the microbial nanowires in Lovley and Tuominen’s labs in 2011, says, “Metallic-like conductivity of the microbial nanowires seemed clear from how it changed with different temperature or pH, but there were still many doubters, especially among biologists.”

To add more support to their hypothesis, Lovley’s lab genetically altered the structure of the nanowires, removing the aromatic amino acids that provide the delocalized electrons necessary for metallic-like conductivity, winning over more skeptics. But EFM provides the final, key evidence, Malvankar says.

“Our imaging shows that charges flow along the microbial nanowires even though they are proteins, still in their native state attached to the cells. Seeing is believing. To be able to visualize the charge propagation in the nanowires at a molecular level is very satisfying. I expect this technique to have an especially important future impact on the many areas where physics and biology intersect.” he adds.

Tuominen says, “This discovery not only puts forward an important new principle in biology but also in materials science. Natural amino acids, when arranged correctly, can propagate charges similar to molecular conductors such as carbon nanotubes. It opens exciting opportunities for protein-based nanoelectronics that was not possible before.”

Lovley and colleagues’ microbial nanowires are a potential “green” electronics component, made from renewable, non-toxic materials. They also represent a new part in the growing field of synthetic biology, he says. “Now that we understand better how the nanowires work, and have demonstrated that they can be genetically manipulated, engineering ‘electric microbes’ for a diversity of applications seems possible.”

One application currently being developed is making Geobacter into electronic sensors to detect environmental contaminants. Another is Geobacter-based microbiological computers. This work was supported by the Office of Naval Research, the U.S. Department of Energy and the National Science Foundation.


Story Source:

The above story is based on materials provided by University of Massachusetts at Amherst. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nikhil S. Malvankar, Sibel Ebru Yalcin, Mark T. Tuominen, Derek R. Lovley.Visualization of charge propagation along individual pili proteins using ambient electrostatic force microscopy. Nature Nanotechnology, 2014; DOI:10.1038/nnano.2014.236

Here’s why I implanted an NFC chip in my hand

Courtesy : Connectedly Credit:  Robert J Nelson
Courtesy : Connectedly Credit: Robert J Nelson

[dropcap]I[/dropcap] have recently taken a deeper step into the connected world. A step that some will describe as being interesting, and that some will describe as being crazy. To be honest, as happy as I am since I have taken this step, I have to admit that I fall on both the interesting and crazy sides myself. Before getting any further, I should mention that the “step” I took was implanting an NFC chip in my hand.

The chip was implanted in my left hand and sits between my thumb and pointer finger. Surprisingly — or thanks to the internet not so surprisingly — a kit that included all the necessary gear was easy to purchase. I made the purchase through a company called Dangerous Things, and for those curious — I paid $99 for a 13.56MHz ISO14443A & NFC Type 2 NTAG216 RFID chipset that is encased in a 2x12mm cylindrical biocompatible glass casing. Essentially that means the chip is safe to implant, and that it will work with all NFC compliant reader/writer devices. That includes USB devices as well as NFC capable mobile phones. This chip is pre-loaded in an injection syringe assembly, and while I wouldn’t trust (or suggest you trust) just anyone to do the procedure, I will say the process was quick, easy — and despite the large size of the needle — relatively painless.

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And for reference, aside from the chip and injection syringe, the remaining items in the kit are medical related (gloves and such). Another personal reason for choosing Dangerous Things was the background on the company. The founder, Amal Graafstra, has been doing this for roughly a decade, and even nicer for those looking to get this done — there is solid documentation offered which may really help make this a reality for some.

On becoming a cyborg

I should make it clear that I am not trying to become a cyborg or anything like that. For me, getting this implant came down to having a strong interest in technology and the connected space, and more to the point is that I am someone who likes seeing technology integrated into life. Or in this case, my body. Along with not considering myself a cyborg, I do not feel comfortable using another common term here, biohacker. I basically think of this implant as another form of wearable, albeit, a semi-permanent form of wearable. Along with my interest in technology, I also have a strong interest in body modification and tattoos.

For me, getting this chip implanted seemed a good way to bridge those interests. And while I realize getting an NFC chip implanted in your hand is not common, I have to mention how hard it was to find people in the piercing and body modification industry (at least locally) that were interested in performing this procedure. Of course, that could also be due to their lack of interest in technology, or maybe due to them not knowing me personally. Putting that aside, how about we get more into my thought process in the lead up to the implant.

Leading up to the implant

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It would be hard for me to recommend this procedure to many people. In fact, I would describe this as a procedure that should be given considerable thought. I had been reading about similar procedures for several years, and had been strongly considering it myself for a little more than a year. In the past, I had put it off due to not wanting to do the research. There was also the case of getting the necessary hardware and the somewhat limited use potential. Well, I finally did the research and that lead me to Dangerous Things — who as mentioned earlier — offer a kit with everything you need. As for the limited use potential, we’ll get into that more in a bit, but I can say that will come down to how much you are willing to spend, and to how much you are willing and able to build.

Implanting the Chip

I mentioned this isn’t a procedure that just anyone should get done, but actually finding someone willing to implant the chip took some effort. As I found, not everyone is going to be willing to implant an NFC chip in your hand. In my case I ended up getting the procedure done by a friend of a friend. And to clarify, that friend of a friend is a medical professional. They had never implanted an NFC chip, however they have been in the medical profession for many years. Furthermore, said medical professional was also very happy to read the documentation provided by the folks at *Dangerous Things. To that point, that documentation also made things much more comfortable for me. Bottom line here, once you come to a decision to get this done, make sure you have someone you can really trust.

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Assuming you find someone willing and able, the actual process of implanting the chip is easy. As I said earlier, it was quick, easy, and relatively painless. Setting up the work area and cleaning my hand took much longer than the actual needle stick. The needle is large and the person getting the chip implanted can expect to feel the initial stick, a push (to get the needle in deeper), a bit of a pull back (of the needle), and then the deposit of the chip which is followed by the removal of the needle. And as you may have noticed in some of the images, there was a bit of blood. Overall pretty simple — that is provided you found someone comfortable and capable of doing the procedure.

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Healing

There really isn’t much to the healing process. The needle is likely the biggest needle you’ve seen or been stuck with, but it is just that — a needle stick. That means there isn’t any cutting or stitches involved. Essentially, you’ll just have a red mark where the needle was inserted. This mark will heal up, and in my case, a month later I can only see a faint mark on my skin. You will also be able to feel the chip under your skin.

Aside from making sure your hand is clean before the stick and the site is kept clean afterward during the healing process, the main thing you want to keep in mind is to take it easy during the first few weeks. The folks at Dangerous Things suggest not messing with the tag, or pressing on the tag, and light use of your hand for the first two weeks. I followed those suggestions myself and things healed nicely and without issue.

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That brings another point to consider. I’ve already mentioned putting serious thought in before getting this done, and also making sure you find someone you trust to do the procedure, however you should also consider what happens if things go bad. In my case, having a medical professional (friend of a friend) do the procedure would not have mattered much if it got infected afterward due to my lack of care. Basically, had things gone bad and I needed the chip removed — that could have created a rather awkward situation (with uncomfortable questions) if I had to go to a doctors office or emergency room.

Putting the Chip to Use

Up until this point I have been using my chip to secure my phone. Pretty boring and basic, but I had a reason for that. First though, I am currently using a 2013 Moto X, and have the chip programmed as a Motorola Skip. I also tested, and would suggest those without a Moto X use the NFC Secure Unlock app which is available from the Google Play Store.

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I decided to keep the use simple and limited to securing my phone initially to keep costs down. This meant I could buy the chip kit (for $99) and spend no additional money until I knew there wasn’t going to be any issues. Now that the chip has been in and has fully healed, I am exploring other options. I’ve been considering a few options including opening my garage door, unlocking my front door, or unlocking my car. The catch here is that I am happy having my phone secured using the chip, and will likely implant another chip in my right hand for whatever I want to control (open or unlock) next. The fact that I am willing to get another chip implanted should speak to how easy the procedure was.

Finally…The Why

Actually, the why is the hardest part to answer. And to be perfectly honest I am not sure I have a good answer. My best response would be to satisfy my curiosity. I also wouldn’t suggest anyone get an implant just for this, but showing people how I can unlock my phone has turned into somewhat of a fun trick.

 

We don’t condone or encourage anyone to get an NFC implant, and take no responsibility if you do. Be sure to think it through and know what you’re getting into should you choose to do so.

Courtesy : Connectedly       ||      Credit:  Robert J Nelson

Electric vehicle technology packs more punch in smaller package

ORNL's 30-kilowatt power inverter offers greater reliability and power in a compact package. Credit: ORNL
ORNL’s 30-kilowatt power inverter offers greater reliability and power in a compact package.
Credit: ORNL

[dropcap]U[/dropcap]sing 3-D printing and novel semiconductors, researchers at the Department of Energy’s Oak Ridge National Laboratory have created a power inverter that could make electric vehicles lighter, more powerful and more efficient.

At the core of this development is wide bandgap material made of silicon carbide with qualities superior to standard semiconductor materials. Power inverters convert direct current into the alternating current that powers the vehicle. The Oak Ridge inverter achieves much higher power density with a significant reduction in weight and volume.

“Wide bandgap technology enables devices to perform more efficiently at a greater range of temperatures than conventional semiconductor materials,” said ORNL’s Madhu Chinthavali, who led the Power Electronics and Electric Machinery Group on this project. “This is especially useful in a power inverter, which is the heart of an electric vehicle.”

Specific advantages of wide bandgap devices include: higher inherent reliability; higher overall efficiency; higher frequency operation; higher temperature capability and tolerance; lighter weight, enabling more compact systems; and higher power density.

Additive manufacturing helped researchers explore complex geometries, increase power densities, and reduce weight and waste while building ORNL’s 30-kilowatt prototype inverter.

“With additive manufacturing, complexity is basically free, so any shape or grouping of shapes can be imagined and modeled for performance,” Chinthavali said. “We’re very excited about where we see this research headed.”

Using additive manufacturing, researchers optimized the inverter’s heat sink, allowing for better heat transfer throughout the unit. This construction technique allowed them to place lower-temperature components close to the high-temperature devices, further reducing the electrical losses and reducing the volume and mass of the package.

Another key to the success is a design that incorporates several small capacitors connected in parallel to ensure better cooling and lower cost compared to fewer, larger and more expensive “brick type” capacitors.

The research group’s first prototype, a liquid-cooled all-silicon carbide traction drive inverter, features 50 percent printed parts. Initial evaluations confirmed an efficiency of nearly 99 percent, surpassing DOE’s power electronics target and setting the stage for building an inverter using entirely additive manufacturing techniques.

Building on the success of this prototype, researchers are working on an inverter with an even greater percentage of 3-D printed parts that’s half the size of inverters in commercially available vehicles. Chinthavali, encouraged by the team’s results, envisions an inverter with four times the power density of their prototype.

Others involved in this work, which was to be presented today at the Second Institute of Electrical and Electronics Engineers Workshop on Wide Bandgap Power Devices and Applications in Knoxville, were Curt Ayers, Steven Campbell, Randy Wiles and Burak Ozpineci.

Research for this project was conducted at ORNL’s National Transportation Research Center and Manufacturing Demonstration Facility, DOE user facilities, with funding from DOE’s Office of Energy Efficiency and Renewable Energy.


Story Source:

The above story is based on materials provided by Oak Ridge National Laboratory.Note: Materials may be edited for content and length.

Scientists create new protein-based material with some nerve

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[dropcap]S[/dropcap]cientists at the University of California, Berkeley, have taken proteins from nerve cells and used them to create a “smart” material that is extremely sensitive to its environment. This marriage of materials science and biology could give birth to a flexible, sensitive coating that is easy and cheap to manufacture in large quantities.

The work, to be published Oct. 14, in the journal Nature Communications, could lead to new types of biological sensors, flow valves and controlled drug release systems, the researchers said. Biomedical applications include microfluidic devices that can handle and process very small volumes of liquid, such as samples of saliva or blood, for diagnostics.

“This work represents a unique convergence of the fields of biomimetic materials, biomolecular engineering and synthetic biology,” said principal investigator Dr. Sanjay Kumar, UC Berkeley associate professor of bioengineering. “We created a new class of smart, protein-based materials whose structural principles are inspired by networks found in living cells.”

Kumar’s research team set out to create a biological version of a synthetic coating used in everyday liquid products, such as paint and liquid cosmetics, to keep small particles from clumping together. The synthetic coatings are often called polymer brushes because of their bristle-like appearance when attached to the particle surface.

To create the biological equivalent of a polymer brush, the researchers turned to neurofilaments, pipe cleaner-shaped proteins found in nerve cells. By acting as tiny, cylindrical polymer brushes, neurofilaments collectively assemble into a structural network that helps keep one end of the nerve cell propped open so that it can conduct electrical signals.

“We co-opted this protein and turned it into a polymer brush by cloning a portion of a gene that encodes one of the neurofilament bristles, re-engineering it such that we could attach the resulting protein to surfaces in a precise and oriented way, and then expressing the gene in bacteria to produce the protein in large, pure quantities,” said Kumar. “We showed that our ‘protein brush’ had all the key properties of synthetic brushes, plus a number of advantages.”

Kumar noted that neurofilaments are good candidates for protein brushes because they are intrinsically disordered proteins, so named because they don’t have a fixed 3-D shape. The size and chemical sequence of these hair-like proteins are far easier to control when compared with their synthetic counterparts.

“In biology, precision is critical,” said Kumar. “Proteins are generally synthesized with the exact same sequence every time; the length and biochemical order of the protein sequence affects all of its properties, including structure and the ability to bind to other molecules and catalyze biochemical reactions. This kind of sequence precision is difficult if not impossible to achieve in the laboratory using the tools of chemical synthesis. By harnessing the precision of biology and letting the bacterial cell do all the work for us, we were able to control the exact length and sequence of the bristles of our protein brush.”

The researchers showed that the protein brushes could be grafted onto surfaces, and that they dramatically expand and collapse in reaction to changes in acidity and salinity. Materials that are environmentally sensitive in this way are often referred to as “smart” materials because of their ability to adaptively respond to specific stimuli.


Story Source:

The above story is based on materials provided by University of California – Berkeley. The original article was written by Sarah Yang. Note: Materials may be edited for content and length.


Journal Reference:

  1. Nithya Srinivasan, Maniraj Bhagawati, Badriprasad Ananthanarayanan, Sanjay Kumar. Stimuli-sensitive intrinsically disordered protein brushes. Nature Communications, 2014; 5: 5145 DOI: 10.1038/ncomms6145

Is matter falling into the massive black hole at the center of the Milky Way or being ejected from it?

This composite of Sagittarius A-Star combines radio images from the NRAO Very Large Array (green), BIMA (red) and the NASA Spitzer Space Telescope (blue). Credit: Image courtesy of NRAO/AUI
This composite of Sagittarius A-Star combines radio images from the NRAO Very Large Array (green), BIMA (red) and the NASA Spitzer Space Telescope (blue).
Credit: Image courtesy of NRAO/AUI

[dropcap]I[/dropcap]s matter falling into the massive black hole at the center of the Milky Way or being ejected from it? No one knows for sure, but a UC Santa Barbara astrophysicist is searching for an answer.

Carl Gwinn, a professor in UCSB’s Department of Physics, and colleagues have analyzed images collected by the Russian spacecraft RadioAstron. Their findings appear in the current issue of The Astrophysical Journal Letters.

RadioAstron was launched into orbit from Baikonur, Kazakhstan, in July 2011 with several missions, one of which was to investigate the scattering of pulsars — the cores of dead stars — by interstellar gas. What the team found led them to examine additional observations of Sagittarius A-Star (A*), the source that marks the Milky Way’s central black hole. Sagittarius A* is visible at radio, infrared and X-ray wavelengths.

This massive black hole — which contains 4 million solar masses — does not emit radiation but is visible from the gas around it. The gas is being acted upon by the black hole’s very strong gravitational field. The wavelengths that make Sagittarius A* visible are scattered by interstellar gas along the line of sight in the same way that light is scattered by fog on Earth.

Gwinn and his colleagues found that the images taken by RadioAstron contained small spots. “I was quite surprised to find that the effect of scattering produced images with small lumps in the overall smooth image,” explained Gwinn. “We call these substructure. Some previous theories had predicted similar effects in the 1980s, and a quite controversial observation in the 1970s had hinted at their presence.”

In order to better understand the substructure, Michael Johnson, Gwinn’s former graduate student now at the Harvard-Smithsonian Center for Astrophysics, conducted theoretical research. He realized that the anomalies could be used to infer the actual size of the underlying source.

Additional observations made using the Very Long Baseline Array — an interferometer consisting of 10 identical antennas distributed across the United States — and the 100-meter Green Bank Telescope in West Virginia showed the presence of lumps in the image of Sagittarius A*. Recent upgrades have greatly increased the sensitivity of these telescopes. Even so, evidence of the lumps, or substructure, remained extremely faint.

“The theory and observations allow us to make statements about the interstellar gas responsible for the scattering, and about the emission region around the black hole,” Johnson said. “It turns out that the size of that emission region is only 20 times the diameter of the event horizon as it would be seen from Earth. With additional observations, we can begin to understand the behavior in this extreme environment.”

While no scientific team has been able to produce a complete image of the black hole’s emission, astronomers have drawn inferences about scattering properties from observations at longer wavelengths. “From these they can extrapolate those properties to 1 centimeter and use that to make a rough estimate of the size of the source,” Gwinn said. “We seem to agree quite well with that estimate.”

Not only did Gwinn and his colleagues directly confirm these indirect inferences about the size of Sagittarius A*, they were also able to provide new information about fluctuations in the interstellar gas that cause scattering. Their work shows that the spectrum of interstellar turbulence is shallow.

“There are different ways of interpreting observations of the scattering, and we showed that one of them is right and the others are wrong,” said co-investigator Yuri Kovalev, the RadioAstron project scientist. “This will be important for future research on the gas near this black hole. This work is a good example of the synergy between different modern research infrastructures, technologies and science ideas.”

A friendly international race is going on to see who will be the first to image the black hole’s emissions and thereby determine whether gas falls into the black hole or is being ejected in the form of a jet.

“The character of the substructure seems to be random, so we are keen to go back and confirm the statistics of our sample with more data,” Gwinn said. “We’re also interested in looking at shorter wavelengths where we think the emission region may be smaller and we can get closer to the black hole. We may be able to extract more information than just the size of the emission region. We might possibly be able to make a simple image of how matter falls into a black hole or is ejected from it. It would be very exciting to produce such an image.”


Story Source:

The above story is based on materials provided by University of California – Santa Barbara. The original article was written by Julie Cohen. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. R. Gwinn, Y. Y. Kovalev, M. D. Johnson, V. A. Soglasnov. DISCOVERY OF SUBSTRUCTURE IN THE SCATTER-BROADENED IMAGE OF SGR A*. The Astrophysical Journal, 2014; 794 (1): L14 DOI: 10.1088/2041-8205/794/1/L14

FYI: Why Do Clouds Stay Up?

A cloud is made up of liquid water droplets. A cloud forms when air is heated by the sun. As it rises, it slowly cools it reaches the saturation point and water condenses, forming a cloud. As long as the cloud and the air that its made of is warmer than the outside air around it, it floats!

Watch this video for better understanding of “Why Do Clouds Stay Up?

 

Rising sea levels of 1.8 meters in worst-case scenario, researchers calculate

The worst-case sea level projections is shown in red. There is 95% certainty that sea level will not rise faster than this upper-limit. Purple shows the likely range of sea level rise as projected in the IPCC fifth assessment report under a scenario with rising emissions throughout the 21st century (RCP8.5). Credit: Aslak Grinsted, NBI
The worst-case sea level projections is shown in red. There is 95% certainty that sea level will not rise faster than this upper-limit. Purple shows the likely range of sea level rise as projected in the IPCC fifth assessment report under a scenario with rising emissions throughout the 21st century (RCP8.5).
Credit: Aslak Grinsted, NBI

[dropcap]T[/dropcap]he climate is getting warmer, the ice sheets are melting and sea levels are rising — but how much? The report of the UN’s Intergovernmental Panel on Climate Change (IPCC) in 2013 was based on the best available estimates of future sea levels, but the panel was not able to come up with an upper limit for sea level rise within this century. Now researchers from the Niels Bohr Institute and their colleagues have calculated the risk for a worst-case scenario. The results indicate that at worst, the sea level would rise a maximum of 1.8 meters.

The results are published in the scientific journal Environmental Research Letters.

What causes the sea to rise is when all the water that is now frozen as ice and lies on land melts and flows into the sea. It is first and foremost about the two large, kilometer-thick ice sheets on Greenland and Antarctica, but also mountain glaciers.

In addition, large amounts of groundwater is pumped for both drinking water and agricultural use in many parts of the world and more groundwater is pumped than seeps back down into the ground, so this water also ends up in the oceans.

Finally, what happens is that when the climate gets warmer, the oceans also get warmer and hot water expands and takes up more space. But how much do the experts expect the sea levels to rise during this century at the maximum?

Melting of the ice sheets

“We wanted to try to calculate an upper limit for the rise in sea level and the biggest question is the melting of the ice sheets and how quickly this will happen. The IPCC restricted their projektions to only using results based on models of each process that contributes to sea level. But the greatest uncertainty in assessing the evolution of sea levels is that ice sheet models have only a limited ability to capture the key driving forces in the dynamics of the ice sheets in relation to climatic impact,” Aslak Grinsted, Associate Professor at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

Aslak Grinsted has therefore, in collaboration with researchers from England and China, worked out new calculations. The researchers have combined the IPCC numbers with published data about the expectations within the ice-sheet expert community for the evolution, including the risk for the collapse of parts of Antarctica and how quickly such a collapse would take place.

“We have created a picture of the propable limits for how much global sea levels will rise in this century. Our calculations show that the seas will likely rise around 80 cm. An increase of more than 180 cm has a likelihood of less than 5 percent. We find that a rise in sea levels of more than 2 meters is improbable,” Aslak Grinsted, but points that the results only concern this century and the sea levels will continue to rise for centuries to come.


Story Source:

The above story is based on materials provided by University of Copenhagen. Note: Materials may be edited for content and length.


Journal Reference:

  1. S Jevrejeva, A Grinsted, J C Moore. Upper limit for sea level projections by 2100. Environmental Research Letters, 2014; 9 (10): 104008 DOI: 10.1088/1748-9326/9/10/104008

Crocodiles are sophisticated hunters: Work as a team to hunt their prey

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[dropcap]R[/dropcap]ecent studies have found that crocodiles and their relatives are highly intelligent animals capable of sophisticated behavior such as advanced parental care, complex communication and use of tools for hunting.

New University of Tennessee, Knoxville, research published in the journal Ethology Ecology and Evolution shows just how sophisticated their hunting techniques can be.

Vladimir Dinets, a research assistant professor in UT’s Department of Psychology, has found that crocodiles work as a team to hunt their prey. His research tapped into the power of social media to document such behavior.

Studying predatory behavior by crocodiles and their relatives such as alligators and caimans in the wild is notoriously difficult because they are ambush hunters, have slow metabolisms and eat much less frequently than warm-blooded animals. In addition, they are mostly nocturnal and often hunt in murky, overgrown waters of remote tropical rivers and swamps. Accidental observations of their hunting behavior are often made by non-specialists and remain unpublished or appear in obscure journals.

[dropcap]T[/dropcap]o overcome these difficulties, Dinets used Facebook and other social media sites to solicit eyewitness accounts from amateur naturalists, crocodile researchers and nonscientists working with crocodiles. He also looked through diaries of scientists and conducted more than 3,000 hours of observations himself.

All that work produced just a handful of observations, some dating back to the 19th century. Still, the observations had something in common — coordination and collaboration among the crocodiles in hunting their prey.

“Despite having been made independently by different people on different continents, these records showed striking similarities. This suggests that the observed phenomena are real, rather than just tall tales or misinterpretation,” said Dinets.

Crocodiles and alligators were observed conducting highly organized game drives. For example, crocodiles would swim in a circle around a shoal of fish, gradually making the circle tighter until the fish were forced into a tight “bait ball.” Then the crocodiles would take turns cutting across the center of the circle, snatching the fish.

Sometimes animals of different size would take up different roles. Larger alligators would drive a fish from the deeper part of a lake into the shallows, where smaller, more agile alligators would block its escape. In one case, a huge saltwater crocodile scared a pig into running off a trail and into a lagoon where two smaller crocodiles were waiting in ambush — the circumstances suggested that the three crocodiles had anticipated each other’s positions and actions without being able to see each other.

“All these observations indicate that crocodilians might belong to a very select club of hunters — just 20 or so species of animals, including humans — capable of coordinating their actions in sophisticated ways and assuming different roles according to each individual’s abilities. In fact, they might be second only to humans in their hunting prowess,” said Dinets.

Dinets said more observations are needed to better understand what exactly the animals are capable of. “And these observations don’t come easily,” he said.

Previous research by Dinets discovered that crocodiles are able to climb trees and use lures such as sticks to hunt prey. More of his crocodile research can be found in his book “Dragon Songs.”


Story Source:

The above story is based on materials provided by University of Tennessee. Note: Materials may be edited for content and length.


Journal Reference:

  1. Vladimir Dinets. Apparent coordination and collaboration in cooperatively hunting crocodilians. Ethology Ecology & Evolution, 2014; 1 DOI:10.1080/03949370.2014.915432