Aquatic osteoporosis' jellifying lakes

Date:

November 19, 2014

Source:

Queen's University

Summary:

A plague of “aquatic osteoporosis” is spreading throughout many North American soft-water lakes due to declining calcium levels in the water and hindering the survival of some organisms. The reduced calcium availability is hindering the survival of aquatic organisms with high calcium requirements and promoting the growth of nutrient-poor, jelly-clad animals.

 

 A handful of Holopedium capsules which are replacing the water flea Daphnia due to declining calcium levels in many lakes.

 

A plague of "aquatic osteoporosis" is spreading throughout many North American soft-water lakes due to declining calcium levels in the water and hindering the survival of some organisms, says new research from Queen's University.

 

Researchers from Queen's, working with colleagues from York University and the University of Cambridge, as well as other collaborators, have identified a biological shift in many temperate, soft-water lakes in response to declining calcium levels after prolonged periods of acid rain and timber harvesting. The reduced calcium availability is hindering the survival of aquatic organisms with high calcium requirements and promoting the growth of nutrient-poor, jelly-clad animals.
In the study, researchers looked at the microscopic organisms (~1 mm) Daphnia and Holopedium -- the latter whose size is greatly increased by its jelly capsule.
"Calcium is an essential nutrient for many lake-dwelling organisms, but concentrations have fallen so low in many lakes that keystone species can no longer survive," says Adam Jeziorski, one of the lead authors of the study and a postdoctoral fellow in the Department of Biology at Queen's.
The research team found that when calcium levels are low, the water flea Daphnia, which has high calcium requirements, becomes less abundant. Importantly, this keystone species is being replaced by its jelly-clad competitor, Holopedium.
"Conditions now favour animals better adapted to lower calcium levels, and these changes can have significant ecological and environmental repercussions," says Dr. Jeziorski.
Tiny fossils from lake sediments were studied to determine the pre-impact conditions of the lakes as the calcium decline began before monitoring programs were in place. Using this technique, the team was able to examine the environmental trends from the past approximately 150 years.
"Lake sediments act like a history book of past changes in a lake, recording what happened before the problem was identified," says John Smol (Biology), Canada Research Chair in Environmental Change. "Jelly-clad invertebrates have been increasing in an alarming number of lakes. This is likely a long-term effect of acid rain on forest soils, logging and forest regrowth."
The increase in jelly-clad invertebrates can have important implications for lake biology, altering food webs, but can also clog water intakes.
"Many lakes we investigated have passed critical thresholds," says Dr. Smol. "We have been reduced to the role of spectator as these changes continue to unfold. Once again we see there are many unexpected consequences of our actions, most of which are negative."
This research was funded by the Natural Sciences and Engineering Research Council of Canada and the Ontario Ministry of the Environment and Climate Change.
The study is published in Proceedings of the Royal Society B.

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Story Source:
The above story is based on materials provided by Queen's University. The original article was written by Rosie Hales. Note: Materials may be edited for content and length.

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Why lizards have bird breath: Iguanas evolved one-way lungs surprisingly like those of birds

Date:

November 17, 2014

Source:

University of Utah

Summary:

Biologists long assumed that one-way air flow was a special adaptation in birds driven by the intense energy demands of flight. But now scientists have shown that bird-like breathing also developed in green iguanas – reptiles not known for high-capacity aerobic fitness. The finding bolsters the case that unidirectional bird-like flow evolved long before the first birds.

 

 University of Utah scientists have shown that green iguanas have bird-like breathing; air flows in a one-directional loop through their lungs. The discovery bolsters the case that this style of breathing evolved in a common ancestor of lizards, snakes, crocodiles and dinosaurs including birds.

 

 

 

Whether birds are breathing in or out, air flows in a one-directional loop through their lungs. This pattern was unexpected and for decades biologists assumed it was unique to birds, a special adaptation driven by the intense energy demands of flight.

But that view is wrong, according to University of Utah scientists who now have shown that bird-like breathing also developed in green iguanas -- reptiles not known for high-capacity aerobic fitness. The finding bolsters the case that unidirectional bird-like flow evolved long before the first birds, arising nearly 300 million years ago in a common ancestor of lizards, snakes, crocodiles and dinosaurs including birds.
"We thought we understood how these lungs work, but in fact most of us were completely wrong," says Colleen Farmer, an associate professor of biology at the U and lead author of the new study published today in Proceedings of the National Academy of Sciences. "People have made a lot of assumptions about how lungs work in animals such as reptiles and crocodiles but they never actually measured flow," she says.
In humans and other mammals, lungs have airways with a tree-like branching structure. A main trunk in each lung splits into branches and twigs. Air flows in and out in a tidal fashion. Oxygen and carbon dioxide pass to and from blood in tiny air sacs, called alveoli, at the tips of the smallest airway branches.
In bird lungs, air loops in one direction through a series of tubes lined with blood vessels for gas exchange. Aerodynamic forces act like valves to sustain the one-way flow through cycles of inhalation and exhalation.
"For years, people thought that the design evolved to meet the energetic demands of flight," Farmer says. "That's all wrong. Iguanas don't fly."
Alligators also have a bird-like pattern of airflow. Farmer and Kent Sanders, a radiologist at the U, revealed that in a 2010 study. It was the first evidence that one-directional lung ventilation might be an innovation pre-dating the origin of birds. Earlier this year, Farmer along with Emma Schachner and Robert Cieri at the U, and James Butler of Harvard University reported that monitor lizards have one-directional airflow through their lungs, too.
Those discoveries left open the possibility that crocs and monitor lizards evolved their bird-like lungs independently, that is, their evolution converged on a design similar to birds. The finding of bird-like lungs in yet another group of reptiles builds a stronger case for an origin in the remote past in a common ancestor.
To make the discovery, Farmer and co-authors Cieri, Schachner and Brent Craven of Pennsylvania State University had to find a way to visualize air moving through iguana lungs. In one set of experiments, they used a surgical scope to look inside the lungs of live iguanas as the lizards inhaled harmless smoke from a theatrical fog machine. They also used probes that measure air speed and volume in dissected lungs. Working from 3-D X-ray imaging of the contours of iguana lungs, Craven made a computer model simulating airflow. The model's predictions closely matched the patterns observed in real lungs. "It was dead-on with the directions of flow we observed," Farmer says.
The revelations make clear that scientists have much to learn about the physiology of lungs in species other than mammals. Textbooks generally assert that air moving in and out of lungs flows down a pressure gradient from a point of higher pressure to one of lower pressure, but Farmer says her group's findings show that in iguana lungs "that's not what's going on at all." The shapes and angles of the lung airways point jets of air that create one-directional flow.
The mechanics aren't fully known yet, but Farmer says a better understanding could inspire new ways to design devices that circulate or filter blood or other fluids without using mechanical valves. "The geometry of these lungs, it is so weird," Farmer says, "I don't think any engineer would dream that up."

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

Scientists employ satellite tags to solve whale-sized mystery

Date:

November 14, 2014

Source:

Wildlife Conservation Society

Summary:

For the first time, scientists working in the waters of Patagonia are using satellite tags to remotely track southern right whales from their breeding/calving grounds in the sheltered bays of Península Valdés, Argentina, to unknown feeding grounds somewhere in the western South Atlantic

 A WCS-led team member just after tagging a young southern right whale nick-named “Papillon.” The white markings are called callosities – large patches of raised tissue. Each whale’s callosities are unique and can be used to identify individual whales.






For the first time, scientists working in the waters of Patagonia are using satellite tags to remotely track southern right whales from their breeding/calving grounds in the sheltered bays of Península Valdés, Argentina, to unknown feeding grounds somewhere in the western South Atlantic. This could eventually provide clues to the cause of one of the largest great whale die-off ever recorded.

The international effort for answers includes members from the Wildlife Conservation Society (WCS), the Aqualie Institute of Brazil, the National Oceanic and Atmospheric Administration (NOAA), and Cascadia Research Collective, working in cooperation with Fundación Patagonia Natural, Instituto de Conservación de Ballenas, the University of California, Davis, the Dirección de Flora y Fauna (Wildlife Service), la Secretaría de Turismo, el Ministerio de Ambiente (Ministry of the Environment) of Argentina's Chubut Province.
The announcement was made as conservationists are holding the 2014 IUCN World Parks Congress in Sydney, Australia -- a once-in-a-decade global forum on protected areas.
Said Dr. Graham Harris, Director of WCS's Argentina Program: "A provincial protected area and a key area with a long history of work by WCS, Peninsula Valdés was declared a UNESCO Biosphere Reserve in June of 2014 due to its importance to protect both terrestrial wildlife and marine species along its waters. As the World Parks Congress in Sydney is underway, it is imperative to highlight the importance of protected areas like Peninsula Valdes to safeguard unique wildlife and habitats."
Over the past month, the team succeeded in affixing satellite transmitters to five southern right whales, a difficult task conducted during varying weather conditions in Golfo Nuevo, one of the two protected gulfs of Península Valdés and an important breeding ground for the southern right whale.
Over the past decade, southern right whale calves have died in unprecedented numbers (more than 400 between 2003-2011) for reasons still unclear to scientists. Different hypotheses for this mortality have been considered, including disease, certain types of contaminant, and harassment and wounding by kelp gulls, a frequent occurrence in Península Valdés.
This new research will help assess where the whales are feeding, namely if there could be any threats to the whales along their migration route or on their feeding grounds and if the research team can conduct additional tagging and studies to determine any issues associated with food or nutritional stress causing calf loss by some mothers.
Dr. Martín Mendez, Assistant Director of WCS's Latin America and the Caribbean Program, said: Over the last several centuries, and as recent as the 1960s, southern right whales were hunted, at times close to the verge of extinction. But they have now managed to rebound in numbers thanks to protected refuges such as Península Valdés. The recent increase in mortality is being caused by something that remains unsolved. Determining where the whales go to feed may offer clues to solving this complex question."
The deployed tags will transmit the geographical position and behavioral information of the animals up to Earth-orbiting satellites multiple times a day, allowing researchers to follow whales remotely. The researchers selected calving females and solitary juveniles for satellite tagging in order to glean insights into habitat use and migratory movements for different sex and age groups.
Sais Alex Zerbini, a whale telemetry expert from NOAA, Cascadia Research, and Aqualie Institute: "Satellite telemetry is the best method to understand the long-term movements and behavior of whales. Tagging individuals of different sex and age classes will let us explore potential differences in how they migrate and use their habitats."
Data accumulated thus far reveal unprecedented information for southern right whales: real-time information on long-range movements across marine regions. Two of the five whales have remained in the waters of Golfo Nuevo, while the other three have already left the bay. One of the animals is currently in deep waters of the South Atlantic, one has been spending its time over the continental shelf, and another has moved into deep offshore waters, but has returned to the continental shelf break. Movements from all whales have lead researchers to some areas where the tagged animals are likely feeding, and further discoveries of feeding grounds for this population may be revealed as the team tracks the movements of tagged animals.
Said Dr. Howard Rosenbaum of WCS's Ocean Giants Program: "The whales are currently in an area where former Soviet whaling expeditions killed more than 1,000 animals in the 1960s. Beyond these whaling records and other occasional sightings, the tagged animals in conjunction with whaling records will provide the best picture of the migration and feeding destinations for this population. As the tags continue to transmit, we hope our whales lead us to new insights about their lives in the vastness of the South Atlantic and provide possible clues related to the die-off."
Growing up to 55 feet in length and weighing up to 60 tons, the southern right whale is the most abundant species of the world's three species of right whale. Unlike the North Atlantic and North Pacific right whales (both Endangered), southern rights have managed to rebound from centuries of commercial whaling, with populations that have grown by as much as approximately seven percent annually since 1970. Of the estimated total population of southern right whales found throughout the entire Southern Hemisphere, around one third use the protected bays of Península Valdés as a breeding and calving habitat between the months of June and December.

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The above story is based on materials provided by Wildlife Conservation Society. Note: Materials may be edited for content and length.

Magnetic fields frozen into meteorite grains tell a shocking tale of solar system birth

Date:

November 13, 2014

Source:

Arizona State University

Summary:

Astrophysicists say that magnetic clues in a meteorite outline the earliest steps in the formation of the solar system and Earth-like planets.

 

 

 

 

 

 

 

(Magnetic field lines (green) weave through the cloud of dusty gas surrounding the newborn Sun. In the foreground are asteroids and chondrules, the building blocks of chondritic meteorites. While solar magnetic fields dominate the region near the Sun, out where the asteroids orbit, chondrules preserve a record of varying local magnetic fields)

 

 

The most accurate laboratory measurements yet made of magnetic fields trapped in grains within a primitive meteorite are providing important clues to how the early solar system evolved. The measurements point to shock waves traveling through the cloud of dusty gas around the newborn Sun as a major factor in solar system formation.

The results appear in a paper published Nov. 13 in the journal Science. The lead author is graduate student Roger Fu of MIT, working under Benjamin Weiss; Steve Desch of Arizona State University's School of Earth and Space Exploration is a co-author of the paper.
"The measurements made by Fu and Weiss are astounding and unprecedented," says Desch. "Not only have they measured tiny magnetic fields thousands of times weaker than a compass feels, they have mapped the magnetic fields' variation recorded by the meteorite, millimeter by millimeter."
Construction debris
It may seem all but impossible to determine how the solar system formed, given it happened about 4.5 billion years ago. But making the solar system was a messy process, leaving lots of construction debris behind for scientists to study.
Among the most useful pieces of debris are the oldest, most primitive and least altered type of meteorites, called the chondrites (KON-drites). Chondrite meteorites are pieces of asteroids, broken off by collisions, that have remained relatively unmodified since they formed at the birth of the solar system. They are built mostly of small stony grains, called chondrules, barely a millimeter in diameter.
Chondrules themselves formed through quick melting events in the dusty gas cloud -- the solar nebula -- that surrounded the young sun. Patches of the solar nebula must have been heated above the melting point of rock for hours to days. Dustballs caught in these events made droplets of molten rock, which then cooled and crystallized into chondrules.
Tiny magnets
As chondrules cooled, iron-bearing minerals within them became magnetized like bits on a hard drive by the local magnetic field in the gas. These magnetic fields are preserved in the chondrules even down to the present day.
The chondrule grains whose magnetic fields were mapped in the new study came from a meteorite named Semarkona, after the place in India where it fell in 1940. It weighed 691 grams, or about a pound and a half.
The scientists focused specifically on the embedded magnetic fields captured by "dusty" olivine grains that contain abundant iron-bearing minerals. These had a magnetic field of about 54 microtesla, similar to the magnetic field at Earth's surface, which ranges from 25 to 65 microtesla.
Coincidentally, many previous measurements of meteorites also implied similar field strengths. But it is now understood that those measurements detected magnetic minerals contaminated by Earth's magnetic field, or even from hand magnets used by meteorite collectors.
"The new experiments," Desch says, "probe magnetic minerals in chondrules never measured before. They also show that each chondrule is magnetized like a little bar magnet, but with 'north' pointing in random directions."
This shows, he says, they became magnetized before they were built into the meteorite, and not while sitting on Earth's surface.
Shocks and more shocks
"My modeling for the heating events shows that shock waves passing through the solar nebula is what melted most chondrules," Desch explains. Depending on the strength and size of the shock wave, the background magnetic field could be amplified by up to 30 times.
He says, "Given the measured magnetic field strength of about 54 microtesla, this shows the background field in the nebula was probably in the range of 5 to 50 microtesla."
There are other ideas for how chondrules might have formed, some involving magnetic flares above the solar nebula, or passage through the sun's magnetic field. But those mechanisms require stronger magnetic fields than what is measured in the Semarkona samples.
This reinforces the idea that shocks melted the chondrules in the solar nebula at about the location of today's asteroid belt, which lies some two to four times farther from the sun than Earth now orbits.
Desch says, "This is the first really accurate and reliable measurement of the magnetic field in the gas from which our planets formed."

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Story Source:
The above story is based on materials provided by Arizona State University. Note: Materials may be edited for content and length.

 

Bacteria become 'genomic tape recorders', recording chemical exposures in their DNA

Date:

November 13, 2014

Source:

Massachusetts Institute of Technology

Summary:

Engineers have transformed the genome of the bacterium E. coli into a long-term storage device for memory. They envision that this stable, erasable, and easy-to-retrieve memory will be well suited for applications such as sensors for environmental and medical monitoring

 MIT engineers have transformed the genome of the bacterium E. coli into a long-term storage device for memory. They envision that this stable, erasable, and easy-to-retrieve memory will be well suited for applications such as sensors for environmental and medical monitoring.

"You can store very long-term information," says Timothy Lu, an associate professor of electrical engineering and computer science and biological engineering. "You could imagine having this system in a bacterium that lives in your gut, or environmental bacteria. You could put this out for days or months, and then come back later and see what happened at a quantitative level."
The new strategy, described in the Nov. 13 issue of the journal Science, overcomes several limitations of existing methods for storing memory in bacterial genomes, says Lu, the paper's senior author. Those methods require a large number of genetic regulatory elements, limiting the amount of information that can be stored.
The earlier efforts are also limited to digital memory, meaning that they can record only all-or-nothing memories, such as whether a particular event occurred. Lu and graduate student Fahim Farzadfard, the paper's lead author, set out to create a system for storing analog memory, which can reveal how much exposure there was, or how long it lasted. To achieve that, they designed a "genomic tape recorder" that lets researchers write new information into any bacterial DNA sequence.
Stable memory
To program E. coli bacteria to store memory, the MIT researchers engineered the cells to produce a recombinase enzyme, which can insert DNA, or a specific sequence of single-stranded DNA, into a targeted site. However, this DNA is produced only when activated by the presence of a predetermined molecule or another type of input, such as light.
After the DNA is produced, the recombinase inserts the DNA into the cell's genome at a preprogrammed site. "We can target it anywhere in the genome, which is why we're viewing it as a tape recorder, because you can direct where that signal is written," Lu says.
Once an exposure is recorded through this process, the memory is stored for the lifetime of the bacterial population and is passed on from generation to generation.
There are a couple of different ways to retrieve this stored information. If the DNA is inserted into a nonfunctional part of the genome, sequencing the genome will reveal whether the memory is stored in a particular cell. Or, researchers can target the sequences to alter a gene. For example, in this study, the new DNA sequence turned on an antibiotic resistance gene, allowing the researchers to determine how many cells had gotten the memory sequence by adding antibiotics to the cells and observing how many survived.
By measuring the proportion of cells in the population that have the new DNA sequence, researchers can determine how much exposure there was and how long it lasted. In this paper, the researchers used the system to detect light, a lactose metabolite called IPTG, and an antibiotic derivative called aTc, but it could be tailored to many other molecules or even signals produced by the cell, Lu says.
The information can also be erased by stimulating the cells to incorporate a different piece of DNA in the same spot. This process is currently not very efficient, but the researchers are working to improve it.
"This work is very exciting because it integrates many useful capabilities in a single system: long-lasting, analog, distributed genomic storage with a variety of readout options," says Shawn Douglas, an assistant professor at the University of California at San Diego who was not involved in the study. "Rather than treating each individual cell as a digital storage device, Farzadfard and Lu treat an entire population of cells as an analog 'hard drive,' greatly increasing the total amount of information that can be stored and retrieved."
Bacterial sensors
Environmental applications for this type of sensor include monitoring the ocean for carbon dioxide levels, acidity, or pollutants. In addition, the bacteria could potentially be designed to live in the human digestive tract to monitor someone's dietary intake, such as how much sugar or fat is being consumed, or to detect inflammation from irritable bowel disease.
These engineered bacteria could also be used as biological computers, Lu says, adding that they would be particularly useful in types of computation that require a lot of parallel processing, such as picking patterns out of an image.
"Because there are billions and billions of bacteria in a given test tube, and now we can start leveraging more of that population for memory storage and for computing, it might be interesting to do highly parallelized computing. It might be slow, but it could also be energy-efficient," he says.
Another possible application is engineering brain cells of living animals or human cells grown in a petri dish to allow researchers to track whether a certain disease marker is expressed or whether a neuron is active at a certain time. "If you could turn the DNA inside a cell into a little memory device on its own and then link that to something you care about, you can write that information and then later extract it," Lu says.
The research was funded by the National Institutes of Health, the Office of Naval Research, and the Defense Advanced Research Projects Agency.

Hungry black hole eats faster than thought possible

Date:

October 8, 2014

Source:

International Centre for Radio Astronomy Research (ICRAR)

Summary:

Astronomers have discovered a black hole that is consuming gas from a nearby star 10 times faster than previously thought possible. The black hole -- known as P13 -- lies on the outskirts of the galaxy NGC7793 about 12 million light years from Earth and is ingesting a weight equivalent to 100 billion billion hot dogs every minute.

 

Primary Image: This is a combined optical/X-ray image of NGC 7793. Inset image: This is a rendering of what P13 would look like close up.

Credit: Primary Credit: X-ray (NASA/CXC/Univ of Strasbourg/M. Pakull et al); Optical (ESO/VLT/Univ of Strasbourg/M. Pakull et al); H-alpha (NOAO/AURA/NSF/CTIO 1.5m); Creative Commons Attribution-No Derivative Works Insert Image credit: created by Tom Russell (ICRAR) using software created by Rob Hynes (Louisiana State University).

 

Astronomers have discovered a black hole that is consuming gas from a nearby star 10 times faster than previously thought possible.

The black hole -- known as P13 -- lies on the outskirts of the galaxy NGC7793 about 12 million light years from Earth and is ingesting a weight equivalent to 100 billion billion hot dogs every minute.

The discovery was published today in the journal Nature.

International Centre for Radio Astronomy Research astronomer Dr Roberto Soria, who is based at ICRAR's Curtin University node, said that as gas falls towards a black hole it gets very hot and bright.

He said scientists first noticed P13 because it was a lot more luminous than other black holes, but it was initially assumed that it was simply bigger.

"It was generally believed the maximum speed at which a black hole could swallow gas and produce light was tightly determined by its size," Dr Soria said.

"So it made sense to assume that P13 was bigger than the ordinary, less bright black holes we see in our own galaxy, the Milky Way."

When Dr Soria and his colleagues from the University of Strasbourg measured the mass of P13 they found it was actually on the small side, despite being at least a million times brighter than the Sun. It was only then that they realised just how much material it was consuming.

"There's not really a strict limit like we thought, black holes can actually consume more gas and produce more light," Dr Soria said.

Dr Soria said P13 rotates around a supergiant 'donor' star 20 times heavier than our own Sun.

He said the scientists saw that one side of the donor star was always brighter than the other because it was illuminated by X-rays coming from near the black hole, so the star appeared brighter or fainter as it went around P13.

"This allowed us to measure the time it takes for the black hole and the donor star to rotate around each other, which is 64 days, and to model the velocity of the two objects and the shape of the orbit," Dr Soria said.

"From this, we worked out that the black hole must be less than 15 times the mass of our Sun."

Dr Soria compared P13 to small Japanese eating champion Takeru Kobayashi.

"As hotdog-eating legend Takeru Kobayashi famously showed us, size does not always matter in the world of competitive eating and even small black holes can sometimes eat gas at an exceptional rate," he said.

Dr Soria said P13 is a member of a select group of black holes known as ultraluminous X-ray sources.

"These are the champions of competitive gas eating in the Universe, capable of swallowing their donor star in less than a million years, which is a very short time on cosmic scales," he said.

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The above story is based on materials provided by International Centre for Radio Astronomy Research (ICRAR). Note: Materials may be edited for content and length.

 

NASA's SDO watches giant filament on the sun

Date:

October 3, 2014

Source:

NASA/Goddard Space Flight Center

Summary:

A snaking, extended filament of solar material currently lies on the front of the sun -- some 1 million miles across from end to end. Filaments are clouds of solar material suspended above the sun by powerful magnetic forces. Though notoriously unstable, filaments can last for days or even weeks.

A dark snaking line in the upper right of these images on Sept. 30, 2014, show a filament of solar material hovering above the sun's surface. NASA's SDO captured the images in extreme UV light – different colors represent different wavelengths of light and different temperatures of solar material.




Asnaking, extended filament of solar material currently lies on the front of the sun-- some 1 million miles across from end to end. Filaments are clouds of solar material suspended above the sun by powerful magnetic forces. Though notoriously unstable, filaments can last for days or even weeks.

NASA's Solar Dynamics Observatory, or SDO, which watches the sun 24 hours a day, has observed this gigantic filament for several days as it rotated around with the sun. If straightened out, the filament would reach almost across the whole sun, about 1 million miles or 100 times the size of Earth.
SDO captured images of the filament in numerous wavelengths, each of which helps highlight material of different temperatures on the sun. By looking at any solar feature in different wavelengths and temperatures, scientists can learn more about what causes such structures, as well as what catalyzes their occasional giant eruptions out into space.
Look at the images to see how the filament appears in different wavelengths. The brownish combination image was produced by blending two wavelengths of extreme UV light with a wavelength of 193 and 335 Angstroms. The red image shows the 304 Angstrom wavelength of extreme UV light.

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The above story is based on materials provided by NASA/Goddard Space Flight Center. Note: Materials may be edited for content and length.

NASA's Swift mission observes mega flares from nearby red dwarf star

 

Date:

September 30, 2014

Source:

NASA/Goddard Space Flight Center

Summary:

On April 23, NASA's Swift satellite detected the strongest, hottest, and longest-lasting sequence of stellar flares ever seen from a nearby red dwarf star. The initial blast from this record-setting series of explosions was as much as 10,000 times more powerful than the largest solar flare ever recorded.

 

DG CVn, a binary consisting of two red dwarf stars shown here in an artist's rendering, unleashed a series of powerful flares seen by NASA's Swift. At its peak, the initial flare was brighter in X-rays than the combined light from both stars at all wavelengths under typical conditions.



On April 23, NASA's Swift satellite detected the strongest, hottest, and longest-lasting sequence of stellar flares ever seen from a nearby red dwarf star. The initial blast from this record-setting series of explosions was as much as 10,000 times more powerful than the largest solar flare ever recorded.

"We used to think major flaring episodes from red dwarfs lasted no more than a day, but Swift detected at least seven powerful eruptions over a period of about two weeks," said Stephen Drake, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who gave a presentation on the "superflare" at the August meeting of the American Astronomical Society's High Energy Astrophysics Division. "This was a very complex event."
At its peak, the flare reached temperatures of 360 million degrees Fahrenheit (200 million Celsius), more than 12 times hotter than the center of the sun.
In April 2014, NASA's Swift mission detected a massive superflare from a red dwarf star in the binary system DG CVn, located about 60 light-years away. Astronomers Rachel Osten of the Space Telescope Science Institute and Stephen Drake of NASA Goddard discuss this remarkable event.
The "superflare" came from one of the stars in a close binary system known as DG Canum Venaticorum, or DG CVn for short, located about 60 light-years away. Both stars are dim red dwarfs with masses and sizes about one-third of our sun's. They orbit each other at about three times Earth's average distance from the sun, which is too close for Swift to determine which star erupted.
"This system is poorly studied because it wasn't on our watch list of stars capable of producing large flares," said Rachel Osten, an astronomer at the Space Telescope Science Institute in Baltimore and a deputy project scientist for NASA's James Webb Space Telescope, now under construction. "We had no idea DG CVn had this in it."
Most of the stars lying within about 100 light-years of the solar system are, like the sun, middle-aged. But a thousand or so young red dwarfs born elsewhere drift through this region, and these stars give astronomers their best opportunity for detailed study of the high-energy activity that typically accompanies stellar youth. Astronomers estimate DG CVn was born about 30 million years ago, which makes it less than 0.7 percent the age of the solar system.
Stars erupt with flares for the same reason the sun does. Around active regions of the star's atmosphere, magnetic fields become twisted and distorted. Much like winding up a rubber band, these allow the fields to accumulate energy. Eventually a process called magnetic reconnection destabilizes the fields, resulting in the explosive release of the stored energy we see as a flare. The outburst emits radiation across the electromagnetic spectrum, from radio waves to visible, ultraviolet and X-ray light.
At 5:07 p.m. EDT on April 23, the rising tide of X-rays from DG CVn's superflare triggered Swift's Burst Alert Telescope (BAT). Within several seconds of detecting a strong burst of radiation, the BAT calculates an initial position, decides whether the activity merits investigation by other instruments and, if so, sends the position to the spacecraft. In this case, Swift turned to observe the source in greater detail, and, at the same time, notified astronomers around the globe that a powerful outburst was in progress.
"For about three minutes after the BAT trigger, the superflare's X-ray brightness was greater than the combined luminosity of both stars at all wavelengths under normal conditions," noted Goddard's Adam Kowalski, who is leading a detailed study on the event. "Flares this large from red dwarfs are exceedingly rare."
The star's brightness in visible and ultraviolet light, measured both by ground-based observatories and Swift's Optical/Ultraviolet Telescope, rose by 10 and 100 times, respectively. The initial flare's X-ray output, as measured by Swift's X-Ray Telescope, puts even the most intense solar activity recorded to shame.
The largest solar explosions are classified as extraordinary, or X class, solar flares based on their X-ray emission. "The biggest flare we've ever seen from the sun occurred in November 2003 and is rated as X 45," explained Drake. "The flare on DG CVn, if viewed from a planet the same distance as Earth is from the sun, would have been roughly 10,000 times greater than this, with a rating of about X 100,000."
But it wasn't over yet. Three hours after the initial outburst, with X-rays on the downswing, the system exploded with another flare nearly as intense as the first. These first two explosions may be an example of "sympathetic" flaring often seen on the sun, where an outburst in one active region triggers a blast in another.
Over the next 11 days, Swift detected a series of successively weaker blasts. Osten compares the dwindling series of flares to the cascade of aftershocks following a major earthquake. All told, the star took a total of 20 days to settle back to its normal level of X-ray emission.
How can a star just a third the size of the sun produce such a giant eruption? The key factor is its rapid spin, a crucial ingredient for amplifying magnetic fields. The flaring star in DG CVn rotates in under a day, about 30 or more times faster than our sun. The sun also rotated much faster in its youth and may well have produced superflares of its own, but, fortunately for us, it no longer appears capable of doing so.
Astronomers are now analyzing data from the DG CVn flares to better understand the event in particular and young stars in general. They suspect the system likely unleashes numerous smaller but more frequent flares and plan to keep tabs on its future eruptions with the help of NASA's Swift.

Earth's water is older than the sun: Likely originated as ices that formed in interstellar space

Date:

September 25, 2014

Source:

Carnegie Institution

Summary:

Water was crucial to the rise of life on Earth and is also important to evaluating the possibility of life on other planets. Identifying the original source of Earth's water is key to understanding how life-fostering environments come into being and how likely they are to be found elsewhere. New work found that much of our solar system's water likely originated as ices that formed in interstellar space.

 

 

Water was crucial to the rise of life on Earth and is also important to evaluating the possibility of life on other planets. Identifying the original source of Earth's water is key to understanding how life-fostering environments come into being and how likely they are to be found elsewhere. New work from a team including Carnegie's Conel Alexander found that much of our Solar System's water likely originated as ices that formed in interstellar space. Their work is published in Science.

Water is found throughout our Solar System. Not just on Earth, but on icy comets and moons, and in the shadowed basins of Mercury. Water has been found included in mineral samples from meteorites, the Moon, and Mars.
Comets and asteroids in particular, being primitive objects, provide a natural "time capsule" of the conditions during the early days of our Solar System. Their ices can tell scientists about the ice that encircled the Sun after its birth, the origin of which was an unanswered question until now.
In its youth, the Sun was surrounded by a protoplanetary disk, the so-called solar nebula, from which the planets were born. But it was unclear to researchers whether the ice in this disk originated from the Sun's own parental interstellar molecular cloud, from which it was created, or whether this interstellar water had been destroyed and was re-formed by the chemical reactions taking place in the solar nebula.
"Why this is important? If water in the early Solar System was primarily inherited as ice from interstellar space, then it is likely that similar ices, along with the prebiotic organic matter that they contain, are abundant in most or all protoplanetary disks around forming stars," Alexander explained. "But if the early Solar System's water was largely the result of local chemical processing during the Sun's birth, then it is possible that the abundance of water varies considerably in forming planetary systems, which would obviously have implications for the potential for the emergence of life elsewhere."
In studying the history of our Solar System's ices, the team -- led by L. Ilsedore Cleeves from the University of Michigan -- focused on hydrogen and its heavier isotope deuterium. Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons. The difference in masses between isotopes results in subtle differences in their behavior during chemical reactions. As a result, the ratio of hydrogen to deuterium in water molecules can tell scientists about the conditions under which the molecules formed.
For example, interstellar water-ice has a high ratio of deuterium to hydrogen because of the very low temperatures at which it forms. Until now, it was unknown how much of this deuterium enrichment was removed by chemical processing during the Sun's birth, or how much deuterium-rich water-ice the newborn Solar System was capable of producing on its own.
So the team created models that simulated a protoplanetary disk in which all the deuterium from space ice has already been eliminated by chemical processing, and the system has to start over "from scratch" at producing ice with deuterium in it during a million-year period. They did this in order to see if the system can reach the ratios of deuterium to hydrogen that are found in meteorite samples, Earth's ocean water, and "time capsule" comets. They found that it could not do so, which told them that at least some of the water in our own Solar System has an origin in interstellar space and pre-dates the birth of the Sun.
"Our findings show that a significant fraction of our Solar System's water, the most-fundamental ingredient to fostering life, is older than the Sun, which indicates that abundant, organic-rich interstellar ices should probably be found in all young planetary systems," Alexander said.

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

Gorilla Glass

Gorilla Glass is the registered trademark for an alkali-aluminosilicate sheet toughened glass manufactured by U.S. glassmaker Corning Inc. Engineered for a combination of thinness, lightness, and damage-resistance, it is used primarily as the cover glass for portable electronic devices including mobile phones, portable media players, laptop computer displays, and some television screens.[1] It is manufactured through immersion in a molten alkaline salt bath using ion exchange to produce compressive residual stress at the surface. This prevents cracks from propagating – for a crack to start, it will first have to overcome this compressive stress.[2]

History.

Corning experimented with chemically strengthened glass in 1960, as part of a "Project Muscle" initiative. Within a few years it had developed a "muscled glass"[3] it named "Chemcor" glass. The product was used until the early 1990s in various commercial and industrial applications, including automotive, aviation and pharmaceutical uses,[3] with particular use in approximately one hundred 1968 Dodge Dart and Plymouth Barracuda racing cars, where minimizing the vehicle's weight is essential.[4] Experimentation was revived in 2005, investigating whether the glass could be made thin enough for use in consumer electronics, and was brought into commercial use when Apple asked Corning for a toughened glass that would eventually go into the iPhone.

Powerful math creates 3-D shapes from simple sketches

Date:

August 13, 2014

Source:

University of British Columbia, Faculty of Science

Summary:

A new graphics system that can easily produce complex 3-D shapes from simple professional sketches will be unveiled by computer scientists. The technology has the potential to dramatically simplify how designers and artists develop new product ideas. Converting an idea into a 3-D model using current commercial tools can be a complicated and painstaking process.

 

 

 

new graphics system that can easily produce complex 3-D shapes from simple professional sketches will be unveiled by University of British Columbia computer scientists at the SIGGRAPH 2014 Conference in Vancouver, Canada this week.

The technology has the potential to dramatically simplify how designers and artists develop new product ideas.
Converting an idea into a 3-D model using current commercial tools can be a complicated and painstaking process. UBC researchers developed True2Form, a software algorithm inspired by the work of professional designers, effectively communicating ideas through simple drawings.
"In line-drawings, designers and artists use descriptive curves and informative viewpoints to convey the full shape of an object," says Alla Sheffer, a professor in UBC's Dept. of Computer Science. "Our system mimics the results of human three-dimensional shape inference to lift a sketch curve network into 3-D, while preserving fidelity to the original sketch."
True2Form uses powerful mathematics to interpret artists' strokes automatically lifting drawings off of the page. It produces convincing, complex 3-D shapes computed from individual sketches, automatically corrected to account for inherent drawing inaccuracy.
The software is designed to render a wider range of geometric complexity than current sketch-based modelling frameworks.
Sheffer, her team from UBC, and colleagues from the University of Toronto and INRIA France will present a technical paper on True2Form on Wednesday, August 13 at the Vancouver Convention Centre as part of SIGGRAPH 2014.
 

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Story Source:
The above story is based on materials provided by University of British Columbia, Faculty of Science. Note: Materials may be edited for content and length.

 

'Honeybee' robots replicate swarm behavior

Date:

September 18, 2014

Source:

University of Lincoln

Summary:

Computer scientists have created a low-cost, autonomous micro-robot which in large numbers can replicate the behavior of swarming honeybees.

Computer scientists have created a low-cost, autonomous micro-robot which in large numbers can replicate the behaviour of swarming honeybees

Colias -- named after a genus of butterfly -- is an open-platform system that can be used to investigate collective behaviours and be applied to swarm applications.
Robotic swarms that take inspiration from nature have become a topic of fascination for robotics researchers, whose aim is to study the autonomous behaviour of large numbers of simple robots in order to find technological solutions to common complex tasks.
Due to the hardware complexities and cost of creating robot hardware platforms, current research in swarm robotics is mostly performed by simulation software. However, the simulation of large numbers of these robots in robotic swarm software applications is often inaccurate due to the poor modelling of external conditions.
Colias was created by a team of scientists led by the University of Lincoln, UK, with Tsinghua University in China. It has been proven to be feasible as an autonomous platform -- effectively replicating a honeybee swarm. Its small size (4cm diameter) and fast motion (35cm/s) means it can be used in fast-paced swarm scenarios over large areas.
In comparison to other mobile robots which are utilized in swarm robotic research, Colias is a low-cost platform, costing around £25, making the replication of swarm behaviour in large numbers of robots more feasible and economical for researchers.
Farshad Arvin, from the School of Computer Science, University of Lincoln, was part of the research team which developed Colias.
He said: "The platform must be able to imitate swarm behaviours found in nature, such as insects, birds and fish. Colias has been designed as a complete platform with supporting software development tools for robotics education and research. This concept allows for the coordination of simple physical robots in order to cooperatively perform tasks. The decentralised control of robotic swarms can be achieved by providing well-defined interaction rules for each individual robot. Colias has been used in a bio-inspired scenario, showing that it is extremely responsive to being used to investigate collective behaviours. Our aim was to imitate the bio-inspired mechanisms of swarm robots and to enable all research groups, even with limited funding, to perform such research with real robots."
Long-range infrared proximity sensors allow the robot to communicate with its direct neighbours at a range of 0.5cm to 2m. A combination of three short-range sensors and an independent processor enables the individual robots to detect obstacles.
A similar but more complex mechanism has been found in locust vision, where a specific neuron called the 'lobula giant movement detector' reacts to objects approaching the insects' eyes.
Co-author Professor Shigang Yue, also from Lincoln's School of Computer Science, previously created a computerised system which supports the autonomous navigation of mobile robots based on the locust's unique visual system.
This earlier research, published in the International Journal of Advanced Mechatronic Systems (2013), could provide the blueprint for the development of highly accurate vehicle collision sensors, surveillance technology and even aid video game programming.
The next step for the Colias research team is to work on an extension of the vision module using a faster computer processor to implement bio-inspired vision mechanisms.
Full details of their research have been published in the International Journal of Advanced Robotic Systems.
The work is supported by the European Union's FP7 project EYE2E, which aims to build international capacity and cooperation in the field of biologically inspired visual neural systems.

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

10 Most Beautiful Villages in Europe

 

 

From the Alps to the Mediterranean, these frozen-in-time European villages will make you appreciate the beauty of taking it slow. Reaching some of these European beauties requires extra effort, yet the rewards are dazzling. Your eyes will thank you.

Hallstatt, Austria

The storybook town of Hallstatt in central Austria enjoys a gorgeous setting on the bank of the Hallstätter See, between the pristine lake and a lush mountain that rises dramatically from the water’s edge. A history of salt mining dating back thousands of years has translated into enduring prosperity for the town, which is most evident in the beautiful square ringed with ivy-covered buildings.

 

Manarola, Italy

Manarola is a small town, a frazione of the comune (municipality) of Riomaggiore, in the province of La Spezia, Liguria, northern Italy. It is the second smallest of the famous Cinque Terre towns frequented by tourists.

 

Bibury, England

The hilly Cotswold region is a designated “Area of Outstanding Natural Beauty” in southwestern England, and one of its loveliest villages is Bibury, where verdant meadows abut ancient stone cottages with steep pitched roofs. The River Coln, which bisects the village, teems with trout, but the most scenic area is Arlington Row, a lane of sepia-hued cottages built in the 17th century to house weavers from the nearby Arlington Mill.

Colmar, France

French and German influences commingle in this well-preserved Alsatian village, where local bakeries sell both croissants and kugelhopf, and restaurants specialize in foie gras and sauerkraut (or choucroute). A range of architectural styles, from German Gothic to French Neo-Baroque, can be spotted in the old town, which was spared destruction during World War II—thanks in part to the historical beauty of its cobblestoned lanes, quiet canals, and half-timbered houses.

Reine, Norway

North of the Arctic Circle, Reine is a pretty fishing village in the Lofoten archipelago, an area of starkly beautiful Nordic wilderness, where sapphire bays punctuate fjords and mountains. Many of the bright red fishermen’s cabins (called rorbuer) have been converted into comfortable cottages for visitors that offer direct access to the Norwegian Sea. Settle in for a front-row view of the night sky and its mesmerizing entertainment, from summer’s midnight sun to winter’s northern lights.

Pučiśća, Croatia

The buses and cruises that stop along Croatia’s sunny Dalmatian coast unleash tourists eager to experience the charms of Dubrovnik and the ancient island village of Hvar. Fewer visitors find their way to Pučiśća on the island of Brač. The reward is a seaside village with outsize appeal: white-stone villas with terracotta roofs, narrow cobblestoned alleys, and a stone-paved square. Bask in its relative solitude and the many prime spots for swimming in the turquoise Adriatic Sea.

Telč, Czech Republic

Residents of Telč, a small town in south Moravia, were once quite competitive about the beauty of their homes, as is evident today on the elongated main square, where one building is lovelier than the next. The Baroque- and Renaissance-style façades, featuring high gables painted in pale pastels, now support small shops and cafés. A grand Renaissance-era château and large fish-filled ponds surround the square.

Cong, Ireland

Encircled by streams, the picturesque village of Cong straddles the border between County Mayo and Galway—a region of lakes and vibrantly green meadows dotted with grazing sheep. Cong counts numerous stone bridges, the ruins of a medieval abbey, the occasional thatched-roof cottage, and Ashford Castle, a grand Victorian estate that has been converted into a romantic luxury hotel.

Gruyères, Switzerland

Gruyères is famous for its namesake cheese, whose mild, nutty flavor melts so well in fondue. But few are familiar with the town itself, a medieval hamlet in the upper valley of the Saane River in western Switzerland. A wide, stone-paved street leads up to the magnificent 13th-century Gruyères Castle, with its imposing fortifications and expansive views of the surrounding Alpine foothills.

Bled, Slovenia

This small Alpine town in northwestern Slovenia rings the shore of Lake Bled, whose glacial blue waters surround a tiny island and its small Baroque church. After a two-hour stroll around the lake, hike to the medieval hilltop castle for panoramic views or recharge with a slice of the local specialty: kremšnita, a sugar-topped pastry filled with cream and custard that has been served for decades at the Hotel Park.

Hints of gravitational waves in the stars

Date:

September 22, 2014

Source:

American Museum of Natural History

Summary:

Scientists have shown how gravitational waves -- invisible ripples in the fabric of space and time that propagate through the universe -- might be 'seen' by looking at the stars. The new model proposes that a star that oscillates at the same frequency as a gravitational wave will absorb energy from that wave and brighten, an overlooked prediction of Einstein's 1916 theory of general relativity. The study contradicts previous assumptions about the behavior of gravitational waves.

Scientists have shown how gravitational waves -- invisible ripples in the fabric of space and time that propagate through the universe -- might be "seen" by looking at the stars. The new model proposes that a star that oscillates at the same frequency as a gravitational wave will absorb energy from that wave and brighten, an overlooked prediction of Einstein's 1916 theory of general relativity. The study, which was published today in the Monthly Notices of the Royal Astronomical Society: Letters, contradicts previous assumptions about the behavior of gravitational waves.

"It's pretty cool that a hundred years after Einstein proposed this theory, we're still finding hidden gems," said Barry McKernan, a research associate in the Museum's Department of Astrophysics, who is also a professor at CUNY's Borough of Manhattan Community College; a faculty member at CUNY's Graduate Center; and a Kavli Scholar at the Kavli Institute for Theoretical Physics.
Gravitational waves can be thought of like the sound waves emitted after an earthquake, but the source of the "tremors" in space are energetic events like supernovae (exploding stars), binary neutron stars (pairs of burned-out cores left behind when stars explode), or the mergers of black holes and neutron stars. Although scientists have long known about the existence of gravitational waves, they've never made direct observations but are attempting to do so through experiments on the ground and in space. Part of the reason why detection is difficult is because the waves interact so weakly with matter. But McKernan and his colleagues from CUNY, the Harvard-Smithsonian Center for Astrophysics, the Institute for Advanced Study, and Columbia University, suggest that gravitational waves could have more of an effect on matter than previously thought.
The new model shows that stars with oscillations -- vibrations -- that match the frequency of gravitational waves passing through them can resonate and absorb a large amount of energy from the ripples.
"It's like if you have a spring that's vibrating at a particular frequency and you hit it at the same frequency, you'll make the oscillation stronger," McKernan said. "The same thing applies with gravitational waves."
If these stars absorb a large pulse of energy, they can be "pumped up" temporarily and made brighter than normal while they discharge the energy over time. This could provide scientists with another way to detect gravitational waves indirectly.
"You can think of stars as bars on a xylophone -- they all have a different natural oscillation frequency," said co-author Saavik Ford, who is a research associate in the Museum's Department of Astrophysics as well as a professor at the Borough of Manhattan Community College, CUNY; a faculty member at CUNY's Graduate Center; and a Kavli Scholar at the Kavli Institute for Theoretical Physics. "If you have two black holes merging with each other and emitting gravitational waves at a certain frequency, you're only going to hit one of the bars on the xylophone at a time. But because the black holes decay as they come closer together, the frequency of the gravitational waves changes and you'll hit a sequence of notes. So you'll likely see the big stars lighting up first followed by smaller and smaller ones."
The work also presents a different way to indirectly detect gravitational waves. From the perspective of a gravitational wave detector on Earth or in space, when a star at the right frequency passes in front of an energetic source such as merging black holes, the detector will see a drop in the intensity of gravitational waves measured. In other words, stars -- including our own Sun -- can eclipse background sources of gravitational waves.
"You usually think of stars as being eclipsed by something, not the other way around," McKernan said.
The researchers will continue to study these predictions and try to determine how long it would take to observe these effects from a telescope or detector.

Amazing macro-photography of individual snowflakes

snowflakes on the open balcony of my house, mostly on glass surface, lighted by an LED flashlight from the opposite side of the glass, and sometimes in natural light, using dark woolen fabrics as background."



 

Solar system also shows signs of windy weather

Date:

September 22, 2014

Source:

National Radio Astronomy Observatory

Summary:

Astronomers have observed what may be the first-ever signs of windy weather around a T Tauri star, an infant analog of our own Sun. This may help explain why some T Tauri stars have disks that glow weirdly in infrared light while others shine in a more expected fashion.

 

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have observed what may be the first-ever signs of windy weather around a T Tauri star, an infant analog of our own Sun. This may help explain why some T Tauri stars have disks that glow weirdly in infrared light while others shine in a more expected fashion.

 

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

 

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

 

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

 

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

 

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

 

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

 

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

 

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

 

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

 

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

Computers 1,000 times faster? Quick-change materials break silicon speed limit for computers

Source:

 

University of Cambridge

Summary:

Faster, smaller, greener computers, capable of processing information up to 1,000 times faster than currently available models, could be made possible by replacing silicon with materials that can switch back and forth between different electrical states.

 

 

 

 

 

Faster, smaller, greener computers, capable of processing information up to 1,000 times faster than currently available models, could be made possible by replacing silicon with materials that can switch back and forth between different electrical states.

The present size and speed limitations of computer processors and memory could be overcome by replacing silicon with 'phase-change materials' (PCMs), which are capable of reversibly switching between two structural phases with different electrical states -- one crystalline and conducting and the other glassy and insulating -- in billionths of a second.

Modelling and tests of PCM-based devices have shown that logic-processing operations can be performed in non-volatile memory cells using particular combinations of ultra-short voltage pulses, which is not possible with silicon-based devices.

In these new devices, logic operations and memory are co-located, rather than separated, as they are in silicon-based computers. These materials could eventually enable processing speeds between 500 and 1,000 times faster than the current average laptop computer, while using less energy. The results are published in the journal Proceedings of the National Academy of Sciences.

The processors, designed by researchers from the University of Cambridge, the Singapore A*STAR Data-Storage Institute and the Singapore University of Technology and Design, use a type of PCM based on a chalcogenide glass, which can be melted and recrystallized in as little as half a nanosecond (billionth of a second) using appropriate voltage pulses.

The calculations performed by most computers, mobile phones and tablets are carried out by silicon-based logic devices. The solid-state memory used to store the results of such calculations is also silicon-based. "However, as demand for faster computers continues to increase, we are rapidly reaching the limits of silicon's capabilities," said Professor Stephen Elliott of Cambridge's Department of Chemistry, who led the research.

The primary method of increasing the power of computers has previously been to increase the number of logic devices which they contain by progressively reducing the size of the devices, but physical limitations for current device architectures mean that this is quickly becoming nearly impossible to continue.

Currently, the smallest logic and memory devices based on silicon are about 20 nanometres in size -- approximately 4000 times thinner than a human hair -- and are constructed in layers. As the devices are made ever smaller in order to increase their numbers on a chip, eventually the gaps between the layers will get so small that electrons which are stored in certain regions of flash non-volatile memory devices will be able to tunnel out of the device, resulting in data loss. PCM devices can overcome this size-scaling limit since they have been shown to function down to about two nanometres.

An alternative for increasing processing speed without increasing the number of logic devices is to increase the number of calculations which each device can perform, which is not possible using silicon, but the researchers have demonstrated that multiple calculations are possible for PCM logic/memory devices.

First developed in the 1960s, PCMs were originally used in optical-memory devices, such as re-writable DVDs. Now, they are starting to be used for electronic-memory applications and are beginning to replace silicon-based flash memory in some makes of smartphones.

The PCM devices recently demonstrated to perform in-memory logic do have shortcomings: currently, they do not perform calculations at the same speeds as silicon, and they exhibit a lack of stability in the starting amorphous phase.

However, the Cambridge and Singapore researchers found that, by performing the logic-operation process in reverse -- starting from the crystalline phase and then melting the PCMs in the cells to perform the logic operations -- the materials are both much more stable and capable of performing operations much faster.

The intrinsic switching, or crystallization, speed of existing PCMs is about ten nanoseconds, making them suitable for replacing flash memory. By increasing speeds even further, to less than one nanosecond (as demonstrated by the Cambridge and Singapore researchers in 2012), they could one day replace computer dynamic random-access memory (DRAM), which needs to be continually refreshed, by a non-volatile PCM replacement.

In a silicon-based system, information is shuffled around, costing both time and energy. "Ideally, we'd like information to be both generated and stored in the same place," said Dr Desmond Loke of the Singapore University of Technology and Design, the paper's lead author. "Silicon is transient: the information is generated, passes through and has to be stored somewhere else. But using PCM logic devices, the information stays in the place where it is generated."

"Eventually, what we really want to do is to replace both DRAM and logic processors in computers by new PCM-based non-volatile devices," said Professor Elliott. "But for that, we need switching speeds approaching one nanosecond. Currently, refreshing of DRAM leaks a huge amount of energy globally, which is costly, both financially and environmentally. Faster PCM switching times would greatly reduce this, resulting in computers which are not just faster, but also much 'greener'."