Knowledge Update

Washington, Feb 7 (IANS) Astronomers have detected a giant black hole that ripped apart a star and then gorged on its remains for an unusually long time -- about a decade, which is more than ten times longer than any observed episode of a stars death by black hole.

Researchers made this discovery using data from NASA's Chandra X-ray Observatory and Swift satellite as well as European Space Agency's XMM-Newton.

The trio of orbiting X-ray telescopes found evidence for a "tidal disruption event" (TDE), wherein the tidal forces due to the intense gravity from a black hole can destroy an object -- such as a star -- that wanders too close. 

During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inwards to be ingested by the black hole, the material heats up to millions of degrees and generates a distinct X-ray flare.

"We have witnessed a star's spectacular and prolonged demise," said lead researcher Dacheng Lin from the University of New Hampshire in Durham, New Hampshire.

"Dozens of tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one," Lin noted.

The extraordinary long bright phase of this event spanning over ten years means that among observed TDEs this was either the most massive star ever to be completely torn apart during one of these events, or the first where a smaller star was completely torn apart, said the study published in the journal Nature Astronomy.

The X-ray source containing this force-fed black hole, known by its abbreviated name of XJ1500+0154, is located in a small galaxy about 1.8 billion light years from Earth.

The sharp X-ray vision of Chandra data showed that XJ1500+0154 is located at the centre of its host galaxy, the expected location for a supermassive black hole.

The X-ray data also indicated that radiation from material surrounding this black hole has consistently surpassed the so-called Eddington limit, defined by a balance between the outward pressure of radiation from the hot gas and the inward pull of the gravity of the black hole. 

​New York, Feb 5 (IANS) A new self-contained robot that mimics the key flight mechanisms of bats has been developed by scientists.

Researchers at the University of Illinois at Urbana-Champaign and Caltech have developed Bat Bot (B2) with soft, articulated wings that can mimic the biological bats.



"Our work demonstrates one of the most advanced designs to date of a self-contained flapping-winged aerial robot with bat morphology that is able to perform autonomous flight," said Alireza Ramezani from the University of Illinois.



The robot weighs 93 grams, with dynamic wing articulations and wing conformations similar to those of biological bats.



The bats have a flight mechanism that involves more than 40 types of joints that interlock the bones and muscles to one another creating a musculoskeletal system that can change shape and is capable of movement in multiple independent directions, researchers said.



"We reduced those numbers to nine joints in the B2 robot. The compliant wings of a bat-like flapping robot flapping at lower frequencies are inherently safe," the study mentioned.



According to the researchers, the robot utilises a morphing skeleton array and a silicone-based membrane skin that enables the robot to change its articulated structure in mid-air without losing an effective and smooth aerodynamic surface.



"When a bat flaps its wings, it's like a rubber sheet. It fills up with air and deforms. And then, at the end of its down-stroke motion, the wing pushes the air out when it springs back into place. So you get this big amplification of power that comes just from the fact you are using flexible membranes inside the wing itself," said Seth Hutchinson, professor at the University of Illinois.



Researchers said that B2 can also contribute biological studies on bat flight.



Researchers believe that B2 can be used to reconstruct flight maneuvers of bats by applying wing movement patterns observed in bat flight, "thereby helping us understand the role of the dominant degrees of freedom of bats".



"Although these approaches can effectively analyse the joint kinematics of bat wings in flight, they cannot help understand how specific wing movement patterns contribute to a particular flight maneuver of a bat," the paper published in AAAS Science Robotics noted.

New York, Feb 5 (IANS) A pacemaker similar to the size of a nickel can be implanted in patients to restore the heart's normal rhythm, when it is unable to pump enough oxygen-rich blood, experts have said.

Pacemakers are the most common way to treat bradycardia to help restore the heart's normal rhythm and relieve symptoms by sending electrical impulses to the heart to increase the heart rate.

Houston Methodist Hospital in Texas is now offering a US Food and Drug Administration (FDA) approved Micra Transcatheter Pacing System (TPS) -- the world's smallest pacemaker for patients with bradycardia, a condition characterized by a slow heart rate, usually fewer than 60 beats per minute.

The device is the size of a large vitamin, and unlike traditional pacemakers, it does not require cardiac wires (leads) or a surgical "pocket" under the skin to deliver a pacing therapy.

"The device is small enough to be delivered through a catheter and implanted directly into the heart, providing a safe alternative to conventional pacemakers without the complications associated with leads," said Paul Schurmann, Managing Director at Houston Methodist Hospital.

"The device also allows us to automatically adjust pacing therapy based on a patient's activity levels and another positive is the battery can last up to 10 years," added Schurmann.

Micra TPS was designed with a unique feature that enables it to be permanently turned off so it can remain in the body and a new device can be implanted without risk of electrical interaction.

​New York, Feb 5 (IANS) Ever wondered what happens on the other side of our skulls when we hit our heads? Now, the world's first tiniest hammer being developed by the US researchers may help understand what happens when force is applied to brain cells, an advance that may help improve treatments for brain injuries as well as Alzheimer's disease.

The "microHammer" -- a tiny cellular-scale machine -- can be used to tap, strike, squeeze and poke individual neural progenitors to elicit responses to unlock the mysteries of the brain.

The device flows through individual cells and subjects each of them to one of a variety of physical forces, the researchers said.

"The microhammer will enable precision measurements of the physical, chemical and biological changes that occur when cells are subjected to mechanical loading, ranging from small perturbations to high-force, high-speed impacts," Megan Valentine from University of California - Santa Barbara, said in a statement. 

The microhammer is currently undergoing the process of characterisation, whereby the types and magnitudes of forces it can apply are being measured and recorded in anticipation of the first set of neuron-smashing experiments.

The microhammer will provide new insight into the causes and progress of brain injuries due to trauma.

It could also pave the way toward a better understanding of neural conditions such as Alzheimer's disease as well as traumatic brain injury -- a currently incurable and often insidious condition -- that affects everyone from soldiers, to athletes in contact sports, to anyone who has an accident, Valentine said.

New York, Feb 4 (IANS) Eating grapes daily can help protect the brain against early decline associated with Alzheimer's disease, show results of a pilot study involving people with early memory decline.

Alzheimer's disease is a brain disease that results in a slow decline of memory and cognitive skills. 

"The study examines the impact of grapes as a whole fruit versus isolated compounds and the results suggest that regular intake of grapes may provide a protective effect against early decline associated with Alzheimer's disease," said lead investigator of the study Daniel Silverman from University of California Los Angeles, US.

"This pilot study contributes to the growing evidence that supports a beneficial role for grapes in neurologic and cardiovascular health, however more clinical studies with larger groups of subjects are needed to confirm the effects observed here," Silverman added.

The study results, published in Experimental Gerontology, showed a grape-enriched diet protected against the decline of metabolic activity. 

Low metabolic activity in these areas of the brain is a hallmark of early stage Alzheimer's disease. 

Additionally, those consuming a grape-enriched diet also exhibited increased metabolism in other areas of the brain that correlated with individual improvements in attention and working memory performance, compared to those on the non-grape diet. 

In the study, participants with early memory decline were randomly selected to receive either whole grape powder -- equivalent to just a little over two cups of grapes per day -- or a polyphenol-free placebo powder matched for flavour and appearance. 

Cognitive performance was measured at baseline and six months later. Changes in brain metabolism, assessed by brain scans, were also measured at baseline and six months later. 

The results showed that consuming grapes preserved healthy metabolic activity in the regions of the brain that are affected by the earliest stages of Alzheimer's disease, where metabolic decline takes hold. 

Participants who did not consume grapes exhibited significant metabolic decline in these critical regions. 

Grape polyphenols help promote antioxidant and anti-inflammatory activities. 

Previous research had shown that grapes may help support brain health by working in multiple ways - from reducing oxidative stress in the brain to promoting healthy blood flow in the brain to helping maintain levels of a key brain chemical that promotes memory to exerting anti-inflammatory effects.

​New York, Feb 4 (IANS) Challenging a common perception that personality traits are ingrained, researchers have found that when preschoolers spend time around one another, they tend to take on each others' personalities.

The study, published online in the Journal of Personality and Social Psychology, suggests personality is shaped by environment and not just genes.

"Our finding, that personality traits are 'contagious' among children, flies in the face of common assumptions that personality is ingrained and can't be changed," said co-investigator on the study Jennifer Watling Neal, Associate Professor at Michigan State University in the US.

"This is important because some personality traits can help children succeed in life, while others can hold them back," she explained. 

For the study, the researchers studied two preschool classes for an entire school year, analysing personality traits and social networks for one class of three-year-olds and one class of four-year-olds.

Children whose play partners were extroverted or hard-working became similar to these peers over time. 

Children whose play partners were over-anxious and easily frustrated, however, did not take on these particular traits, the study said.

Washington, Feb 3 (IANS) The dwarf planet Ceres may actually host many "hidden" ice volcanoes, besides the only one discovered recently, a study says.

NASA's Dawn spacecraft discovered Ceres's four-kilometre tall Ahuna Mons cryovolcano in 2015. 

Other icy worlds in our solar system, like Pluto, Europa, Triton, Charon and Titan, may also have such mountains of icy rock -- called cryovolcanoes -- but Ahuna Mons is conspicuously alone on Ceres. 

Now, in a paper accepted for publication in the journal Geophysical Research Letters, scientists showed there might have been cryovolcanoes other than Ahuna Mons on Ceres millions or billions of years ago, but these cryovolcanoes might have flattened out over time and become indistinguishable from the planet's surface. 

"We think we have a very good case that there have been lots of cryovolcanoes on Ceres but they have deformed," said lead study author Michael Sori of Lunar and Planetary Laboratory at University of Arizona in Tucson, US.

Ahuna Mons is a prominent feature on Ceres, rising to about half the height of Mount Everest. Its solitary existence has puzzled scientists since they spied it.

Adding to the puzzle are the steep sides and well-defined features of Ahuna Mons -- usually signs of geologic youth, Sori said. 

That leads to two possibilities. Ahuna Mons is just as it appears, inexplicably alone after forming relatively recently on an otherwise inactive world. Or, the cryovolcano is not alone or unusual, and there is some process on Ceres that has destroyed its predecessors and left the young Ahuna Mons as the solitary cryovolcano on the dwarf planet, according to Sori.

Ceres has no atmosphere, so the processes that wear down volcanoes on Earth -- wind, rain and ice -- are not possible on the dwarf planet. 

Sori and his colleagues hypothesised that another process, called viscous relaxation, could be at work.

Viscous relaxation is the idea that just about any solid will flow, given enough time. For example, a cold block of honey appears to be solid. But if given enough time, the block will flatten out until there is no sign left of the original block structure.

On Earth, viscous relaxation is what makes glaciers flow, Sori explained. 

"Ahuna Mons is at most 200 million years old. It just has not had time to deform," Sori said.

The researchers said they would next try and identify the flattened remnants of older cryovolcanoes on Ceres. 

The findings could help scientists better decipher the history of how the dwarf planet formed, Sori added.

​New York, Feb 3 (IANS) Sleep may be regulated in part by several brain-based immune proteins, says a study that could pave the way for new therapies to treat chronic sleep disorders and sleep disturbances secondary to other diseases.

The immune proteins -- collectively called inflammasome NLRP3 -- recruit a sleep-inducing molecule to trigger somnolence following sleep deprivation and exposure to a bacterial toxin, showed results of the study published in the journal Brain, Behavior, and Immunity.

Animals lacking genes for this protective immune complex showed profound sleep aberrations.

"Our research points, for the first time, to the inflammasome acting as a universal sensing mechanism that regulates sleep through the release of immune molecules," said study senior investigator Mark Zielinski from Harvard Medical School. 

In a series of experiments, the scientists demonstrated that following sleep deprivation or exposure to bacteria, the inflammasome activates an inflammatory molecule called interleukin-1 beta, known to induce sleep and promote sleep intensity. 

The brain cells of mice lacking the gene coding for inflammasome NLRP3 showed a marked absence of this sleep-inducing molecule.

Going a step further, the investigators compared the behaviour, sleep patterns and electrical activity in the brains of mice lacking the inflammasome gene to those in a group of mice with intact inflammasome genes.

Mice lacking the inflammasome gene had abnormal sleep responses following sleep deprivation. 

On average, such mice slept less and experienced more sleep interruptions than mice with their genes intact.

The latter group also slept more and harder following bacterial exposure -- the expected physiological response following infection, the researchers said.

Tokyo, Feb 3 (IANS) Examining a molecular cloud with enigmatic motion, a team led by researchers in Japan has found signs of stray black hole hiding in the Milky Way.

It is difficult to find black holes, because they are completely black. In some cases black holes cause effects which can be seen. 

Theoretical studies have predicted that 100 million to one billion black holes should exist in the Milky Way, although only 60 or so have been identified through observations to date. 

"We found a new way of discovering stray black holes," said one of the researchers Tomoharu Oka, Professor at Keio University in Japan.

The researchers used the ASTE Telescope in Chile and the 45-m Radio Telescope at Nobeyama Radio Observatory, both operated by the National Astronomical Observatory of Japan, to observe molecular clouds around the supernova remnant W44, located 10,000 light-years away from us. 

A supernova is the explosion of a star -- the largest explosion that takes place in space, according to NASA.

The primary goal of the researchers was to examine how much energy was transferred from the supernova explosion to the surrounding molecular gas, but they happened to find signs of a hidden black hole at the edge of W44, said the study published in Astrophysical Journal Letters.

During the survey, the team found a compact molecular cloud with enigmatic motion. 

To investigate the origin of this cloud, named the "Bullet", the team performed intensive observations of the gas cloud.

The data indicated that the Bullet seems to jump out from the edge of the supernova remnant with immense kinetic energy. 

"Most of the Bullet has an expanding motion with a speed of 50 km/s, but the tip of the Bullet has a speed of 120 km/s," Masaya Yamada, a graduate student at Keio University, said.

"Its kinetic energy is a few tens of times larger than that injected by the W44 supernova. It seems impossible to generate such an energetic cloud under ordinary environments," Yamada added.

The researchers believe that a dark and compact gravity source, possibly a black hole, has an important role in the formation of the Bullet.