Quantum computers come closer to reality (Re-Issue)

Washington, July 1 (ANI): A team led by Yale University researchers has created the first rudimentary solid-state quantum processor, taking another step toward the ultimate dream of building a quantum computer.

They also used the two-qubit superconducting chip to successfully run elementary algorithms, such as a simple search, demonstrating quantum information processing with a solid-state device for the first time.

“Our processor can perform only a few very simple quantum tasks, which have been demonstrated before with single nuclei, atoms and photons,” said Robert Schoelkopf, the William A. Norton Professor of Applied Physics and Physics at Yale.

“But this is the first time they’ve been possible in an all-electronic device that looks and feels much more like a regular microprocessor,” he added.

Working with a group of theoretical physicists led by Steven Girvin, the Eugene Higgins Professor of Physics and Applied Physics, the team manufactured two artificial atoms, or qubits (“quantum bits”).

While each qubit is actually made up of a billion aluminum atoms, it acts like a single atom that can occupy two different energy states.

These states are akin to the “1″ and “0″ or “on” and “off” states of regular bits employed by conventional computers.

Because of the counterintuitive laws of quantum mechanics, however, scientists can effectively place qubits in a “superposition” of multiple states at the same time, allowing for greater information storage and processing power.

These sorts of computations, though simple, have not been possible using solid-state qubits until now in part because scientists could not get the qubits to last long enough.

While the first qubits of a decade ago were able to maintain specific quantum states for about a nanosecond, Schoelkopf and his team are now able to maintain theirs for a microsecond-a thousand times longer, which is enough to run the simple algorithms.

To perform their operations, the qubits communicate with one another using a “quantum bus”-photons that transmit information through wires connecting the qubits-previously developed by the Yale group.

“The key that made the two-qubit processor possible was getting the qubits to switch “on” and “off” abruptly, so that they exchanged information quickly and only when the researchers wanted them to,” said Leonardo DiCarlo, a postdoctoral associate in applied physics at Yale’s School of Engineering and Applied Science and lead author of the research paper.

Next, the team will work to connect more qubits to the quantum bus.

“The processing power increases exponentially with each qubit added, so the potential for more advanced quantum computing is enormous,” Schoelkopf said. (ANI)

Quantum computers come closer to reality

Washington, June 29 (ANI): A team led by Yale University researchers has created the first rudimentary solid-state quantum processor, taking another step toward the ultimate dream of building a quantum computer.

They also used the two-qubit superconducting chip to successfully run elementary algorithms, such as a simple search, demonstrating quantum information processing with a solid-state device for the first time.

“Our processor can perform only a few very simple quantum tasks, which have been demonstrated before with single nuclei, atoms and photons,” said Robert Schoelkopf, the William A. Norton Professor of Applied Physics and Physics at Yale.

“But this is the first time they’ve been possible in an all-electronic device that looks and feels much more like a regular microprocessor,” he added.

Working with a group of theoretical physicists led by Steven Girvin, the Eugene Higgins Professor of Physics and Applied Physics, the team manufactured two artificial atoms, or qubits (“quantum bits”).

While each qubit is actually made up of a billion aluminum atoms, it acts like a single atom that can occupy two different energy states.

These states are akin to the “1″ and “0″ or “on” and “off” states of regular bits employed by conventional computers.

Because of the counterintuitive laws of quantum mechanics, however, scientists can effectively place qubits in a “superposition” of multiple states at the same time, allowing for greater information storage and processing power.

These sorts of computations, though simple, have not been possible using solid-state qubits until now in part because scientists could not get the qubits to last long enough.

While the first qubits of a decade ago were able to maintain specific quantum states for about a nanosecond, Schoelkopf and his team are now able to maintain theirs for a microsecond-a thousand times longer, which is enough to run the simple algorithms.

To perform their operations, the qubits communicate with one another using a “quantum bus”-photons that transmit information through wires connecting the qubits-previously developed by the Yale group.

“The key that made the two-qubit processor possible was getting the qubits to switch “on” and “off” abruptly, so that they exchanged information quickly and only when the researchers wanted them to,” said Leonardo DiCarlo, a postdoctoral associate in applied physics at Yale’s School of Engineering and Applied Science and lead author of the research paper.

Next, the team will work to connect more qubits to the quantum bus.

“The processing power increases exponentially with each qubit added, so the potential for more advanced quantum computing is enormous,” Schoelkopf said. (ANI)

Lasers can be used to lengthen quantum bit memory by 1,000 times

Washington, June 25 (ANI): Physicists have found that lasers can be used to drastically prolong the shelf life of quantum bit memory, the 0s and 1s of quantum computers, by 1,000 times.

These precarious bits, formed in this case by arrays of semiconductor quantum dots containing a single extra electron, are easily perturbed by magnetic field fluctuations from the nuclei of the atoms creating the quantum dot.

This perturbation causes the bits to essentially forget the piece of information they were tasked with storing.

A quantum dot is a semiconductor nanostructure that is one candidate for creating quantum bits.

The scientists, including the University of Michigan’s Duncan Steel, used lasers to elicit a previously undiscovered natural feedback reaction that stabilizes the quantum dot’s magnetic field, lengthening the stable existence of the quantum bit by several orders of magnitude, or more than 1,000 times.

Because of their ability to represent multiple states simultaneously, quantum computers could theoretically factor numbers dramatically faster and with smaller computers than conventional computers.

For this reason, they could vastly improve computer security.

“In our approach, the quantum bit for information storage is an electron spin confined to a single dot in a semiconductor like indium arsenide,” said Steel.

“One of the serious problems in quantum computing is that anything that disturbs the phase of one of these spins relative to the other causes a loss of coherence and destroys the information that was stored,” he added.

A major cause of information loss in a popular class of semiconductors called 3/5 materials is the interaction of the electron (the quantum bit) with the nuclei of the atoms in the quantum dot holding the electron.

Trapping the electron in a particular spin, as is necessary in quantum computers, gives rise to a small magnetic field that couples with the magnetic field in the nuclei and breaks down the memory in a few billionths of a second.

By exciting the quantum dot with a laser, the scientists were able to block the interaction of these magnetic fields.

The laser causes an electron in the quantum dot to jump to a higher energy level, leaving behind a charged hole in the electron cloud.

This hole, or space vacated by an electron, also has a magnetic field due to the collective spin of the remaining electron cloud.

It turns out that the hole acts directly with the nuclei and controls its magnetic field without any intervention from outside except the fixed excitation by the lasers to create the hole. (ANI)

Lasers can be used to lengthen quantum bit memory by 1,000 times

Washington, June 25 (ANI): Physicists have found that lasers can be used to drastically prolong the shelf life of quantum bit memory, the 0s and 1s of quantum computers, by 1,000 times.

These precarious bits, formed in this case by arrays of semiconductor quantum dots containing a single extra electron, are easily perturbed by magnetic field fluctuations from the nuclei of the atoms creating the quantum dot.

This perturbation causes the bits to essentially forget the piece of information they were tasked with storing.

A quantum dot is a semiconductor nanostructure that is one candidate for creating quantum bits.

The scientists, including the University of Michigan’s Duncan Steel, used lasers to elicit a previously undiscovered natural feedback reaction that stabilizes the quantum dot’s magnetic field, lengthening the stable existence of the quantum bit by several orders of magnitude, or more than 1,000 times.

Because of their ability to represent multiple states simultaneously, quantum computers could theoretically factor numbers dramatically faster and with smaller computers than conventional computers.

For this reason, they could vastly improve computer security.

“In our approach, the quantum bit for information storage is an electron spin confined to a single dot in a semiconductor like indium arsenide,” said Steel.

“One of the serious problems in quantum computing is that anything that disturbs the phase of one of these spins relative to the other causes a loss of coherence and destroys the information that was stored,” he added.

A major cause of information loss in a popular class of semiconductors called 3/5 materials is the interaction of the electron (the quantum bit) with the nuclei of the atoms in the quantum dot holding the electron.

Trapping the electron in a particular spin, as is necessary in quantum computers, gives rise to a small magnetic field that couples with the magnetic field in the nuclei and breaks down the memory in a few billionths of a second.

By exciting the quantum dot with a laser, the scientists were able to block the interaction of these magnetic fields.

The laser causes an electron in the quantum dot to jump to a higher energy level, leaving behind a charged hole in the electron cloud.

This hole, or space vacated by an electron, also has a magnetic field due to the collective spin of the remaining electron cloud.

It turns out that the hole acts directly with the nuclei and controls its magnetic field without any intervention from outside except the fixed excitation by the lasers to create the hole. (ANI)

Planck satellite all set to measure the Big Bang

Berlin, May 13 (ANI): Together with ESA’s (European Space Agency’s) Space Telescope Herschel, Planck is all set to go into orbit on May 14, to begin its studies of the cosmic microwave radiation and of the clues it gives about the Big Bang, the earliest phases of the cosmic history, and the structure and composition of the Universe. ccording to the standard model of cosmology, our Universe began 13.7 billions years ago in a Big Bang, the origin of Space and Time.

The Cosmic Microwave Background (CMB) is the relic heat from this Big Bang, released 380,000 years after beginning and still traveling freely through space today.

At that early time, weak fluctuations of matter density were present, which are seen as variations of temperature in the CMB.

By observing these fluctuations, cosmologists can infer how the large-scale structure of today’s Universe – galaxies, galaxy clusters and filaments – were formed.

The Planck satellite will be placed at the second Lagrangian point of the Sun-Earth-Moon system (L2), located about 1.5 million kilometers away from the Earth – four times the distance to the Moon.

It will spin around its own axis, which will always point towards the Sun, with each rotation recording another strip of the sky and mapping its temperature to an accuracy of about one million of a degree.

The data are sent to Earth and turned into temperature maps of the sky in data processing centers in France and Italy.

What the maps look like depends on certain characteristics of the Universe, for example on the curvature of space.

For hypothetic Universes with specified properties, computer simulations using the MPA software generate virtual maps, which will be compared with maps of the real sky.

“From the comparison, we can draw conclusions about the structure of our own Universe, for example how much ordinary matter and dark energy exist in it,” explained Torsten Ensslin, head of the Planck group at MPA (The Max Planck Institute for Astrophysics).

From their computer simulations, MPA cosmologists have shown how the CMB has influenced the gravitational field of dark matter.

The unseen structures of dark matter can therefore be deduced from temperature variations in the CMB.

The mission is expected to detect thousands of distant objects in a frequency range barely studied so far, and so to offer new insights into the physics of galaxies, Active Galactic Nuclei and quasars in the submillimeter domain.

These will show Planck scientists energetic processes in the immediate vicinity of massive black holes.

Planck may also help us to understand the birth of the first stars in the Universe and the structure of our own galaxy, the Milky Way. (ANI)

Lead may have caused global cooling in 20th century

London, April 20 (ANI): A new research has suggested that particles of lead from gasoline exhaust may have offset warming in the 20th century, causing global cooling.

It’s well known that particles in the atmosphere such as mineral dust, pollen, heavy metals and even bacteria can act as seeds for the nucleation of ice crystals.

These crystals form clouds that can affect the Earth’s energy balance by reflecting the sun’s rays back into space, for example.

According to a report in New Scientist, Dan Cziczo and colleagues of the Pacific Northwest National Laboratory in Richland, Washington, created artificial clouds in the laboratory to explore the ice nucleation efficiency of various particles.

Over a third of the ice nuclei generated contained lead, suggesting it is a highly-efficient nucleator.

They found similar proportions of lead in atmospheric mineral dust samples collected in Switzerland.

Cziczo argues that lead “supercharges” ice-nucleating dust particles in the atmosphere.

According to his calculations, global infrared emission would be 0.8 watts per square meter higher if all atmospheric ice crystals contained lead compared with none.

“Before leaded fuel was phased out from road vehicles last century, the atmosphere contained substantially more leaded particulates than today,” said Cziczo.

This may have helped offset greenhouse warming from about 1940 to 1980, when global temperatures rose little before rising steeply. (ANI)

Modified magnetic resonance imaging may help picture disease metabolism in action

Washington, March 27 (ANI): Duke University researchers have devised a new MRI signalling method that can help see such molecular changes inside the body as may signal health problems like cancer.

Warren Warren, James B. Duke Professor of chemistry at Duke, says that the novel method makes more of the body’s chemistry visible by MRI.

When used for brain imaging, MRI enlist the hydrogen atoms in water to create a graphic display in response to magnetic pulses and radio waves.

However, a huge array of water molecules are needed to pull that off.

“Only one out of every 100,000 water molecules in the body will actually contribute any useful signal to build that image. The water signal is not much different between tumors and normal tissue, but the other internal chemistry is different. So detecting other molecules, and how they change, would aid diagnosis,” Warren said.

The Duke researchers claim that they have been able to see these other molecules with MRI by “hyperpolarizing” some atoms in a sample, adjusting the spins of their nuclei to drastically increase their signal.

According to the team, this creates large imbalances among the populations of those spin states, making the molecules into more powerful magnets.

The researchers say that unlike normal MRI, hyperpolarization and a technique called “dynamic nuclear polarization” (DNP) can produce strong MRI signals from a variety of other kinds of atoms besides water.

Detecting signals from atoms besides water is exceedingly difficult without hyperpolarization because the signal size is so small, but “these signals are strong enough to see, even though the molecules are much more complex than water,” Warren said.

His group uses the “first DNP hyperpolarizer in the South”, which is installed in his laboratory.

The researchers also use Duke’s Small Molecule Synthesis Facility to create custom molecular architectures.

“You thus have a signal that, at least transiently, can be thousands or ten thousands times stronger than regular hydrogen in an MRI. It lets you turn molecules you are interested in into MRI lightbulbs,” Warren said.

The Duke group is evaluating the potentials for a number of possible signalling molecules, such as those involved in Parkinson’s disease, osteoporosis and bladder control, said Warren.

A research article on the new method has been published in the journal Science. (ANI)

Scientists find new evidence for existence of “cold fusion”

Washington, March 24 (ANI): Scientists have across evidence for the existence of low-energy nuclear reactions (LENR), the process once called “cold fusion” that may promise a new source of energy.

Low-energy nuclear reactions could potentially provide 21st Century society a limitless and environmentally clean energy source for generating electricity, according to researchers.

“Our finding is very significant,” said study co-author and analytical chemist Pamela Mosier-Boss, of the U.S. Navy’s Space and Naval Warfare Systems Center (SPAWAR) in San Diego, California. “To our knowledge, this is the first scientific report of the production of highly energetic neutrons from an LENR device,” she added.

Fusion is the energy source of the sun and the stars.

Scientists had been striving for years to tap that power on Earth to produce electricity from an abundant fuel called deuterium that can be extracted from seawater.

Everyone thought that it would require a sophisticated new genre of nuclear reactors able to withstand temperatures of tens of millions of degrees Fahrenheit.

Martin Fleishmann and Stanley Pons, however, claimed achieving nuclear fusion at comparatively “cold” room temperatures in 1989 in a simple tabletop laboratory device termed an electrolytic cell.

But, other scientists could not reproduce their results, and the whole field of research declined.

A stalwart cadre of scientists persisted, however, seeking solid evidence that nuclear reactions can occur at low temperatures.

One of their problems involved extreme difficulty in using conventional electronic instruments to detect the small number of neutrons produced in the process.

In the new study, Mosier-Boss and colleagues inserted an electrode composed of nickel or gold wire into a solution of palladium chloride mixed with deuterium or “heavy water” in a process called co-deposition.

A single atom of deuterium contains one neutron and one proton in its nucleus.

Researchers passed electric current through the solution, causing a reaction within seconds. The scientists then used a special plastic, CR-39, to capture and track any high-energy particles that may have been emitted during reactions, including any neutrons emitted during the fusion of deuterium atoms.

At the end of the experiment, they examined the plastic with a microscope and discovered patterns of “triple tracks,” tiny-clusters of three adjacent pits that appear to split apart from a single point.

The researchers said that the track marks were made by subatomic particles released when neutrons smashed into the plastic.

Importantly, Mosier-Boss and colleagues believe that the neutrons originated in nuclear reactions, perhaps from the combining or fusing deuterium nuclei.

“People have always asked ‘Where’s the neutrons?’” Mosier-Boss said. “If you have fusion going on, then you have to have neutrons. We now have evidence that there are neutrons present in these LENR reactions,” she added. (ANI)

US nuclear relic dating back to 1944 found in bottle

London, March 3 (ANI): Scientists have found a discarded bottle at a waste site in the US that contains the oldest sample of bomb-grade plutonium made in a nuclear reactor, dating back to 1944.

According to a report by BBC News, the sample dates to 1944 and is a relic from the infancy of the US nuclear weapons programme.

A team from the Pacific Northwest National Laboratory used nuclear forensic techniques to date the sample and track down its origins.

The type of plutonium in the bottle – known as Pu-239 – is a so-called alpha emitter. These alpha particles are too bulky to penetrate skin or paper, but they can cause poisoning if swallowed or inhaled.

It has a half-life (the time it takes for half the radioactive nuclei in a sample to decay) of 24,110 years.

The bottle in question was discovered in a burial trench at the Hanford nuclear site in Washington state, north-western US.

Established as part of the Manhattan Project in 1943, Hanford was home to the world’s first full-scale plutonium production facility.

The Manhattan Project was the US’ bid to build the world’s first nuclear weapon during World War II. The project’s roots lay in fears that Nazi Germany was investigating similar technology.

The Hanford site is now the focus of a massive environmental cleanup effort due to high levels of radioactive waste that remain at the site.

While excavating a burial trench in December 2004, clean-up personnel discovered a safe which contained a jug filled with whitish liquid slurry.

Further tests revealed the bottle contained a type of plutonium made by re-processing spent fuel in a manner consistent with early operations at Hanford.

Realising the historic potential of the find, Jon Schwantes and colleagues from the Pacific Northwest National Laboratory carried out further tests on the sample.

In order to determine its age, the researchers analysed the different forms, or isotopes, of plutonium and uranium in the sample.

They found it had been separated from the spent fuel in 1944.

In order to determine which reactor had produced the sample, they compared plutonium isotope ratios from the contents of the bottle against technical data from nuclear research reactors that were operating at the time the sample was made.

Their results strongly suggested the plutonium was manufactured at the prototype X-10 reactor at Oak Ridge in Tennessee, which began operating in 1943, a year after the Manhattan Project was authorised. (ANI)

When it comes to sex, male butterflies use ‘dipstick method’ to beat rivals

London, Jan 14 (ANI): When it comes to butterflies, sex is not as graceful an affair as one might think, claims a new study, which found that male monarch butterflies decide how much of their own sperm to deposit based on the female’s mating history.

To reach the conclusion, Michelle Solensky of The College of Wooster in Ohio paired male monarch butterflies with a selection of females that had had different numbers of partners.

She found that males could selectively increase or decrease the amount of fertile sperm in their deposits. For example, they deposited slightly more into a female for each of her previous mates

The study has been published in the journal Animal Behaviour.

“This may explain earlier observations that the last male to mate has a reproductive advantage,” New Scientist quoted Solenksy, as saying.

Later, the researcher arranged for some female butterflies to receive a large deposit from a single male, and others to have a small deposit from three different males adding up to a similar volume.

When males later mated with the females, they used the same amount of sperm irrespective of which experimental group the female butterfly had been in. This showed that the males were adjusting their sperm on the basis of volume – not the number of previous partners.

“I don’t know of any other creatures that respond to the amount of sperm inside their mates,” Solensky added.

“The new aspect for butterflies is that they can assess the intensity of sperm competition without ever witnessing previous matings,” says Simone Immler at the University of Sussex in the UK.

Since monarch butterflies don’t use chemical signals like pheromones, Solensky suspects that sensors on the male penis detect the volume directly, like the dipstick in a car’s oil tank.

If so, the cells that lack nuclei may act to bump up the volume of the deposit and discourage rivals.

Sensors on the male monarch butterfly’s penis may detect the volume of sperm directly, like the dipstick in a car’s oil tank. (ANI)

When it comes to sex, male butterflies use ‘dipstick method’ to beat rivals

London, Jan 14 (ANI): When it comes to butterflies, sex is not as graceful an affair as one might think, claims a new study, which found that male monarch butterflies decide how much of their own sperm to deposit based on the female’s mating history.

To reach the conclusion, Michelle Solensky of The College of Wooster in Ohio paired male monarch butterflies with a selection of females that had had different numbers of partners.

She found that males could selectively increase or decrease the amount of fertile sperm in their deposits. For example, they deposited slightly more into a female for each of her previous mates

The study has been published in the journal Animal Behaviour.

“This may explain earlier observations that the last male to mate has a reproductive advantage,” New Scientist quoted Solenksy, as saying.

Later, the researcher arranged for some female butterflies to receive a large deposit from a single male, and others to have a small deposit from three different males adding up to a similar volume.

When males later mated with the females, they used the same amount of sperm irrespective of which experimental group the female butterfly had been in. This showed that the males were adjusting their sperm on the basis of volume – not the number of previous partners.

“I don’t know of any other creatures that respond to the amount of sperm inside their mates,” Solensky added.

“The new aspect for butterflies is that they can assess the intensity of sperm competition without ever witnessing previous matings,” says Simone Immler at the University of Sussex in the UK.

Since monarch butterflies don’t use chemical signals like pheromones, Solensky suspects that sensors on the male penis detect the volume directly, like the dipstick in a car’s oil tank.

If so, the cells that lack nuclei may act to bump up the volume of the deposit and discourage rivals.

Sensors on the male monarch butterfly’s penis may detect the volume of sperm directly, like the dipstick in a car’s oil tank. (ANI)

Type 2 diabetes linked to signalling pathway behind pancreatic development

Washington, February 13 (ANI): A group of stem cell researchers from the University of California San Diego (UC San Diego) and Burnham Institute for Medical Research (Burnham) have found that type 2 diabetes is associated with a signalling pathway that is involved in normal pancreatic development.

Revealing their findings online in Experimental Diabetes Research, the researchers said that they could provide a potential new target for therapy.

The team’s study showed that the Wnt signalling pathway is up-regulated in insulin producing cells of pancreases from adults with type 2 diabetes.

“It is now clear that progenitor cells, with the capacity to become insulin producing cells, reside in the adult pancreas,” said Dr. Pamela Itkin-Ansari, assistant adjunct professor at the UC San Diego School of Medicine and Burnham.

“The key to harnessing those cells to treat diabetes is to understand the signaling pathways that are active in the pancreas under both normal and disease conditions. In the course of that research we found that Wnt signaling activity, which plays a critical role in the development of the pancreas, re-emerges in type 2 diabetes,” the researcher added.

The researchers describe the Wnt signaling pathway as a series of protein interactions that control several genes that play a role in normal development, as well as cancer, in many tissues.

In the current study, they compared the expression of different proteins in the Wnt pathway in the pancreas from adults with type 2 diabetes and those from healthy individuals.

It was observed that cells from those without the disease had low levels of beta-catenin, a protein that enters cell nuclei and activates certain genes.

The researchers also found that beta cells from people with type 2 diabetes had increased levels of the protein.

According to them, the activation of the Wnt pathway also up-regulates the expression of c-myc, which has been implicated in the destruction of insulin-producing beta cells.

Given that Wnt signalling was apparent in obese mice well before they developed symptoms, the researchers believe that it may be an important factor leading to Type 2 diabetes.(ANI)

Black holes not guilty of shutting down star formation

Washington, Jan 22 (ANI): A team of astronomers from Yale University has found evidence that indicates black holes are not responsible for shutting down star formation.

They discovered that galaxies stop forming stars long before their central supermassive black holes reach their most powerful stage.

Until recently, astronomers believed that active galactic nuclei (AGN), the supermassive, extremely energetic black holes at the centers of many young galaxies, were responsible for shutting down star formation in their host galaxies once they grew large enough.

It was thought that AGN feed on the surrounding galactic material, producing enormous amounts of energy (expelled in the form of light) and heat the surrounding material so that it can no longer cool and condense into stars.

But, new research shows that this shutting-down process appears to take place much earlier in the AGN’s lifetime, well before it starts shining brightly.

“This high-luminosity phase, when the AGN are at their biggest and brightest and most powerful, is not the phase responsible for the shutdown of star formation,” said Kevin Schawinski, a postdoctoral associate in Yale’s astronomy department and lead author of the study.

The researchers analyzed images of 177 galaxies taken by two different space telescopes to create a comprehensive view of galaxies with AGN, including ones where the AGN were both obscured by the galaxy’s dust and gas, and ones where there was an unobstructed view of the AGN from the Earth’s vantage point.

Until now, some astronomers believed they can’t see AGN in any galaxies that are still actively forming stars simply because the light from the AGN is obscured by the galaxy’s gas and dust.

Schawinski and his team are the first to show that in fact there are no bright AGN at the centers of star-forming galaxies.

By subtracting out the light from the AGN, the team discovered that all of the galaxies with bright AGN had stopped forming stars several hundred million years earlier.

“The key result is the finding that there is a lack of AGN in galaxies that are currently forming stars,” said Meg Urry, head of the Yale team and director of the Yale Center for Astronomy and Astrophysics. “That tells us the AGN doesn’t turn on until long after the stars stop forming,” Urry added.

As for the real culprit, responsible for shutting down star formation, “it’s possible that an earlier, low-luminosity phase is responsible,” said Schawinski.

“Either way, this result shows that our previous understanding of how the shutting-down process works wasn’t as simple as we thought,” he added. (ANI)

Scientists come up with most detailed picture of an organism’s evolutionary process

Washington, Jan 17 (ANI): New evidence from a study of yeast cells has resulted in the most detailed picture of an organism’s evolutionary process to date.

The evidence was found by a Texas A and M University chemical engineering professor, whose findings provide the first direct evidence of aspects, which up until now have remained mostly theory.

Working with populations of yeast cells, which were color-coded by fluorescent markers, Katy Kao, assistant professor in the Artie McFerrin Department of Chemical Engineering, and Stanford University colleague Gavin Sherlock were able to evolve the cells while maintaining a visual analysis of the entire process.

Their research shows the evolutionary process to be much more dynamic than initially thought, with multiple beneficial adaptations arising within a population.

These adaptations, Kao explained, triggered a competition between these segments, known as “clonal interference.”

“It’s the first direct experimental evidence of this phenomenon in eukaryotic cells, or cells with nuclei, and it contrasts the widely accepted classical model of evolution, which doesn’t account for simultaneously developing beneficial adaptations,” she said.

Instead, that model adopts a linear approach, theorizing that a population acquires such adaptations successively, one after another.

Rather than a competition occurring, the model posits a complete replacement of one generation by another better-adapted generation.

That wasn’t the case in Kao’s sample.

Observing the color-coded yeast populations as they evolved to respond to their environment, Kao saw some colors expand while others contracted – a sign that adaptations were occurring.

But, rather than one segment of the population continuing to shrink until it was completely replaced, some segments were able to compete long enough to acquire further adaptations.

When this happened, Kao explained, these populations of cells, once apparently less-fit, began to swell while once-dominant populations started to shrink.

This constant reduction and burgeoning of populations signaled the development of multiple beneficial adaptations and a subsequent competition by the cells that acquired them, according to Kao.

“Essentially, we were watching evolution in action,” Kao said.

“We’re watching evolution in real time. We’re actually seeing a mutation that shows these things have adapted and seeing their population thrive and expand from this adaptation. This is how evolution works,” she added. (ANI)

X-ray survey reveals differences between near and far galaxies

Washington, Jan 7 (ANI): An ongoing X-ray survey undertaken by NASA”s Swift spacecraft is revealing differences between nearby active galaxies and those located about halfway across the universe.

Understanding these differences will help clarify the relationship between a galaxy and its central black hole.

“There”s a lot we don”t know about the workings of supermassive black holes,” said Richard Mushotzky of NASA”s Goddard Space Flight Center in Greenbelt, Maryland.

Astronomers think the intense emission from the centers, or nuclei, of active galaxies arises near a central black hole containing more than a million times the sun”s mass.

“Some of these feeding black holes are the most luminous objects in the universe. Yet, we don”t know why the massive black hole in our own galaxy and similar objects are so dim,” said Mushotzky.

NASA”s Swift spacecraft is designed to hunt gamma-ray bursts. But, in the time between these almost-daily cosmic explosions, Swift”s Burst Alert Telescope (BAT) scans the sky.

The survey is now the largest and most sensitive census of the high-energy X-ray sky.

“The BAT sees about half of the entire sky every day. Now, we have cumulative exposures for most of the sky that exceed 10 weeks,” said Mushotzky.

Galaxies that are actively forming stars have a distinctly bluish color (“blue and booming”), while those not doing so appear quite red.

Nearly a decade ago, surveys with NASA”s Chandra X-Ray Observatory and ESA”s XMM-Newton showed that active galaxies some 7 billion light-years away were mostly massive “red and dead” galaxies in normal environments.

The BAT survey looks much closer to home, within about 600 million light-years.

There, the colors of active galaxies fall midway between blue and red. Most are spiral and irregular galaxies of normal mass, and more than 30 percent are colliding.

“This is roughly in line with theories that mergers shake up a galaxy and ”feed the beast” by allowing fresh gas to fall toward the black hole,” Mushotzky said.

Until the BAT survey, astronomers could never be sure they were seeing most of the active galactic nuclei.

An active galaxy”s core is often obscured by thick clouds of dust and gas that block ultraviolet, optical and low-energy X-ray light.

Dust near the central black hole may be visible in the infrared, but so are the galaxy”s star-formation regions.

Seeing the black hole”s radiation through dust it has heated gives us a view that is one step removed from the central engine.

“Hard” X-rays – those with energies between 14,000 and 195,000 electron volts, can penetrate the galactic gunk and allow a clear view. (ANI)