Knowledge Update

​New York, Dec 16 (IANS) A new planetary system has been discovered with a host star similar to the Earth's Sun but its unusual composition indicates that it has 'eaten' some of its planets.

The study that was published in the journal "Astronomy and Astrophysics" suggest that this new discovery can provide clues to researchers about how planetary systems evolve over time.

"It does not mean that the Sun will 'eat' the Earth any time soon," said Jacob Bean, Assistant Professor University of Chicago.

However, "our discovery provides an indication that violent histories may be common for planetary systems, including our own" Bean said.

In 1995, astronomers discovered the first planet orbiting a star other than the sun. 

Two thousand exoplanets were identified since then including some rare planets that orbit a star similar to Earth's Sun.

Researchers at University of Chicago studied star HIP68468, which is 300 light years away, as part of a multi-year project to discover planets that orbit solar twins. 

"It is tricky to draw conclusions from a single system to study more stars like this to see whether this is a common outcome of the planet formation process," cautioned Megan Bedell, co-author of the study.

The researchers said that the study of HIP68468 was a post-mortem of this process happening around another star similar to our sun and that the discovery deepened their understanding of the evolution of planetary systems.

"HIP68468's composition points to a history of ingesting planets. It contains four times more lithium than would be expected for a star that is six billion years old, as well as a surplus of refractory elements -- metals resistant to heat that are abundant in rocky planets," the research found.

Scientists used the 3.6-meter telescope at La Silla Observatory in Chile to discover their first exoplanet in 2015. 

"The more recent discovery needs to be confirmed, but includes two planet candidates -- a super Neptune and a super Earth. Their orbits are surprisingly close to their host star, with one 50 per cent more massive than Neptune and located at a Venus-like distance from its star. 

"The other, the first super Earth around a solar twin, is three times the Earth's mass and so close to its star that its orbit takes just three days," the study noted.

The scientists said that these two planets most likely did not form where they see them today. 

"Instead, they probably migrated inward from the outer parts of the planetary system. Other planets could have been ejected from the system -- or ingested by their host star," the researchers added.

Researchers continue to explore more than 60 solar twins, eyeing for more exoplanets.

​New York, Dec 16 (IANS) Using the internet in classrooms for study purposes, is likely to affect academic performance, even among the most intelligent and motivated of students, researchers warned.

When internet is used in classrooms, students tend to spend most of their time on social media, reading email, shopping for items such as clothes or watching videos, that could lead to poorer scores.

Internet's use was a significant predictor of students' final exam score, even when their intelligence and motivation were taken into account, said lead author Susan Ravizza, Associate Professor Michigan State University in the US. 

"The detrimental relationship associated with non-academic internet use raises questions about the policy of encouraging students to bring their laptops to class when they are unnecessary for class use," Ravizza said.

Previous research has shown that taking notes on a laptop is not as beneficial for learning as writing notes by hand. 

"Once students crack their laptop open, it is probably tempting to do other sorts of internet-based tasks that are not class-relevant," Ravizza added. 

For the study, the team studied internet use on laptop in a one-hour lecture course with 127 students.

The study showed that using the internet for class purposes did not help students' test scores. 

The findings are forthcoming in the journal Psychological Science.

Mumbai, Dec 15 (IANS) A study by Indian researchers suggests that a population of neutron stars can generate gravitational waves continuously, a finding that could provide an opportunity to study these waves almost permanently.

The study by Professor Sudip Bhattacharyya of the Tata Institute of Fundamental Research (TIFR), Mumbai, and Professor Deepto Chakrabarty of the Massachusetts Institute of Technology (MIT) in the US found that a population of neutron stars should spin around their axes much faster than the highest observed spin rate of any neutron star. 

The observed lower spin rates are possible if these neutron stars emit gravitational waves continuously, and hence spin down, the researchers said.

Gravitational waves emitted by massive objects is a prediction of Albert Einstein's general theory of relativity, which has recently been discovered during transient phenomena of black hole mergers. 

But the detection of continuous gravitational waves, which could provide an opportunity to study these waves almost permanently, is still elusive. 

Neutron stars are the densest observable objects in the universe, with a fistful of stellar material outweighing a mountain on Earth. 

While such stars are not bigger than a city, in size, they have more material than in the Sun crammed inside them. 

A population of these stars can increase their spin rate by the transfer of matter from a normal companion star. 

In fact, some of them have been observed to spin several hundred times in a second around their own axes.

In the 1970s, it was theoretically worked out how fast these neutron stars could spin, and since then this has formed the basis of studies of these stars. 

But the new study -- published in the The Astrophysical Journal -- showed that for episodic mass transfer, which happens for many neutron stars, the stellar spin rate should be much higher, and the star could easily attain a spin rate more than a thousand times per second. 

Since no neutron star has been observed with such a high spin rate, the team pointed out that many of these stars are likely to be slowed down by continuously emitting gravitational waves.

The new study provides a strong indication that many fast spinning neutron stars generate gravitational waves continuously, and careful observations should be made to detect such waves.

​Washington, Dec 15 (IANS) US space agency NASA launched a constellation of eight small satellites on Thursday designed to aid weather forecasters in understanding and predicting hurricane intensity.

The eight observatories comprising the Cyclone Global Navigation Satellite System (CYGNSS) were delivered to a low-Earth orbit by the US aerospace firm Orbital ATK's Pegasus XL rocket at 8.37 a.m. (local time), Xinhua news agency reported.

The rocket and its micro-satellite payload were air-launched from Orbital ATK's modified L-1011 aircraft, nicknamed Stargazer, which first flew to about 39,000 feet over the Atlantic Ocean and then released the rocket.

NASA said the $157 million CYGNSS mission will team up with the Global Positioning System (GPS) constellation to measure ocean surface winds in and near the eye of the storm throughout the life cycle of hurricanes.

"This will be the first time that satellites can peer through heavy tropical rainfall into the middle of hurricanes and predict how intense they are before and during landfall," it added.

​London, Dec 15 (IANS) Researchers have in a breakthrough study found that brains of people genetically inclined towards Alzheimer's are likely to show abnormal immune reactions as early as about seven years before the expected onset of dementia.

These immune responses can be detected by means of a protein known as "TREM2" and found in the cerebrospinal fluid, offering physicians the possibility to trace the progression of the disease, the study said. 

Thus, when the researchers measured the levels of TREM2 -- segregated by certain immune cells of the brain called microglia -- they were able to detect an increasing immune activity of the brain. 

"The activity of the microglia is stimulated by the dying brain cells, not by the deposits of amyloid proteins, called plaques, which also occur in Alzheimer's disease," said Christian Haass, Professor at Ludwig Maximilian University (LMU) in Munich, Germany.

The rise of TREM2 levels years before the expected occurrence of dementia symptoms can be monitored and thus the timing for the onset of dementia can be precisely predicted, the researchers noted.

"TREM2 levels could therefore be a biomarker used to track immune activity while Alzheimer's is progressing, irrespective of whether the disease is genetic or not. TREM2 may also serve as a therapeutic marker to monitor drug response," explained Michael Ewers, Professor at Ludwig Maximilian University (LMU). 

For the study, the team included 127 individuals, with an average age of 40 years, who had a genetic predisposition to Alzheimer's. The vast majority showed no symptoms of dementia or had only minor cognitive impairments. 

The study results are published in the journal Science Translational Medicine.

​London, Dec 15 (IANS) A cost-effective saliva test may have the potential to act as non-invasive marker of immunity and thus enable assessment of vaccination and protection against bacterial infections such as pneumococcal infections in the human body, a study has found.

Saliva test can be an attractive method of specimen collection particularly for children and the elderly, the researchers said.

"Saliva sampling is non-invasive, requires no specialist training or equipment, and may be more cost-effective," said lead author Jennifer Heaney from the University of Birmingham in Britain.

The study showed that IgG Pn antibodies in saliva correlated with antibody levels in serum in infants. 

Protection against bacterial infection is usually inferred by measuring antibody levels in blood serum.

But taking blood samples involves a number of logistical considerations and may not always be feasible, especially in developing countries or where children are involved. 


"The suggestion that antibody levels in saliva may be indicative of those in serum therefore has important implications for markers of immunity and vaccination in many parts of the world," Heaney added. 

Previous research showed that lower levels of antibodies in saliva are associated with of an elevated risk of mortality, and that saliva sampling to determine IgA secretion rate has the potential to be used as an indicator of overall health by professionals as part of a general check-up.

For the study, samples of both blood and saliva were taken from 72 healthy adults. Samples were then analysed to test for concentrations of IgG, IgM and IgA antibodies against 12 pneumococcal (Pn) antigens.

The results showed that in general, higher antibody concentrations in serum were associated with higher concentrations in saliva, with the strongest relationships observed for IgA antibodies.

The study was published in the journal Biomarkers.

​New York, Dec 14 (IANS) NASA's Curiosity rover has detected boron for the first time on the surface of Mars, indicating the potential for long-term habitable groundwater in the ancient past.

"No prior mission to Mars has found boron," said Patrick Gasda of the US Department of Energy's Los Alamos National Laboratory in New Mexico. 

"If the boron that we found in calcium sulfate mineral veins on Mars is similar to what we see on Earth, it would indicate that the groundwater of ancient Mars that formed these veins would have been 0-60 degrees Celsius and neutral-to-alkaline pH," Gasda noted.

The temperature, pH, and dissolved mineral content of the groundwater could make it habitable, according to the scientists.

The boron was identified by the rover's laser-shooting Chemistry and Camera (ChemCam) instrument, which was developed at Los Alamos National Laboratory in conjunction with the French space agency. 

Boron is famously associated with arid sites where much water has evaporated away. However, environmental implications of the boron found by Curiosity are still open to debate.

Whether Martian life has ever existed is still unknown. No compelling evidence for it has been found. When Curiosity landed in Mars' Gale Crater in 2012 the mission's main goal was to determine whether the area ever offered an environment favourable for microbes.

Curiosity is currently climbing a layered Martian mountain and finding rock-composition evidence of how ancient lakes and wet underground environments changed, billions of years ago.

The discovery of boron is only one of several recent findings related to the composition of Martian rocks. 

Hematite and clay minerals are among the other ingredients found to be more abundant in layers farther uphill, compared with lower, older layers examined earlier in the mission.

"The boron and clay underline the mobility of elements and electrons, and that is good for life," John Grotzinger of the California Institute of Technology, Pasadena, California, pointed out.

The findings were discussed in San Francisco during the American Geophysical Union conference.

​London, Dec 14 (IANS) A sound sleep in the first 24 hours after suffering a trauma can help individuals with post traumatic stress disorder (PTSD) to process the horrific experiences, a study has found.

People with PTSD experience highly emotional and distressing memories or even flashbacks where they feel as if they were experiencing the trauma all over again. 

Sleep could play a key role in processing what they have suffered.

"Our approach offers an important non-invasive alternative to the current attempts to erase traumatic memories or treat them with medication," said lead author Birgit Kleim from the University of Zurich. 

The findings showed that a good sleep can help weaken emotions connected to an existing memory, such as fear caused by traumatic experiences. 

In addition, sleep also helps contextualise the recollections, processing them as information and storing the memories. 

However, the process may take several nights, the researchers said.

"The use of sleep might prove to be a suitable and natural early prevention strategy," Kleim added.

For the study, the researchers showed participants a traumatic video. The recurring memories of the images in the film that haunted the participants for a few days were recorded in detail in a diary. 

Study participants were randomly assigned to two groups. One slept in the lab for a night after the video while their sleep was recorded via an electroencephalograph (EEG), the other group remained awake. 

The results revealed that people who slept after the film had fewer and less distressing recurring emotional memories than those who were awake.

"This supports the assumption that sleep may have a protective effect in the aftermath of traumatic experiences," Kleim said, in the study published in the journal Sleep.

​London, Dec 14 (IANS) A drug used for sleep disorder could also reduce the impulse for food, thereby helping food addicts to lose weight, a study says.

The researchers discovered that a drug called Modafinil, usually used for narcolepsy, shift work disorder and excessive daytime sleepiness, can reduce impulsivity and thus food addiction.

"We found Modafinil, which is already on the market, did reduce people's impulsive behaviour," said Ivo Vlaev, Professor at University of Warwick in Britain.

Impulsive behaviour is an important factor that could lead to to food addiction.

"It has been shown to reduce impulsiveness in a variety of disorders such as alcohol dependence, schizophrenia and ADHD (Attention-deficit/hyperactivity disorder). Food addicts suffer from the same neurobiological conditions so we believe it will help food addicts as well and our initial tests have backed up that theory," Vlaev noted.

This could have important implications for people who are obese. 

"There is mounting evidence to show that there is a substantial number of obese people who are food addicts because they have an inability to control their impulsive actions and this drug has shown it can give them more control, which will help overweight people lose weight and so improve their health," Vlaev said.

Food addicts have also been found to have a deficiency in a certain type of dopamine so that their sense of reward and pleasure is diminished, thus they have to eat more to reach the same level of pleasure as anybody else.

The drug, which is sold under a wide variety of brand names around the world, was one of two drugs tested by researchers, the other being Atomoxetine. 

Both drugs have been used for impulsive conditions, including ADHD.

In a paper published in the journal Personality and Individual Differences, the scientists conducted a series of trials on 60 men aged between 19 and 32, with 20 taking a placebo, 20 Atomoxetine and 20 Modafinil.

The tests revealed that those who had taken Modafinil had a significantly reduced level of impulsiveness, whereas Atomoxetine produced no difference compared to the placebo group.

"Modafinil was found to have an effect on impulsivity in healthy individuals and so would be able to have an even bigger effect on food addicts, who are lacking in certain types of dopamine," Vlaev said.

​New York, Dec 13 (IANS) An intense flare detected last year in a distant galaxy about four billion light years from Earth, considered to be the brightest supernova ever observed, is actually a tidal disruption event (TDE) -- the destruction of a star by a rapidly spinning supermassive black hole, suggests new research.

The findings are based on new astronomical observation data from the Las Cumbres Observatory (LCO), a global robotic telescope network, and the Hubble Space Telescope.

"We observed the source for 10 months following the event and have concluded that the explanation is unlikely to lie with an extraordinarily bright supernova," said lead researcher Giorgos Leloudas from Weizmann Institute of Science in Israel.

"Our results indicate that the event was probably caused by a rapidly spinning supermassive black hole as it destroyed a low-mass star," Leloudas explained.

Using images from the Hubble Space Telescope that were not available when the event, called ASASSN-15lh, was observed, the scientists found that the event occurred at the centre of the galaxy where the supermassive black hole resides. 

The black hole inferred to lie in this galaxy is more than 100 million times the mass of the sun.

For a star to be tidally disrupted by such a massive black hole -- rather than swallowed whole -- the black hole must be spinning very rapidly, said the study published in the journal Nature Astronomy.

This discovery marks the first time that a TDE has been used to probe the spin of a black hole, a property that is very difficult to measure and is used to infer the existence of so-called Kerr black holes.

ASASSN-15lh occurred when the star strayed too close to the supermassive black hole and was torn apart by the tides generated by the extreme gravity. 

The stellar material orbited around the black hole, collided with itself at high velocity and started falling into the black hole. 

This released copious amounts of energy and generated the bright flare astronomers observed as ASASSN-15lh.

"Years ago we just wouldn't have been able to follow an event like this," study co-author Andy Howell, University of California, Santa Barbara, US, noted.

"This study shows that large area surveys, a global robotic telescope network and a NASA satellite can come together to reveal dramatic new discoveries that wouldn't be possible without each piece of that puzzle," Howell said.