Knowledge Update

​New York, Feb 15 (IANS) In a surprising discovery, astronomers have observed a black hole producing cold, star-making fuel from hot plasma jets and bubbles.

The researchers found that powerful radio jets from the black hole -- which normally suppress star formation -- are stimulating the production of cold gas in the galaxy's extended halo of hot gas. 

This newly identified supply of cold, dense gas could eventually fuel future star birth as well as feed the black hole itself, said the study published in the Astrophysical Journal.

The researchers studied a galaxy at the heart of the Phoenix Cluster, an uncommonly crowded collection of galaxies about 5.7 billion light-years from Earth.

The team analysed observations of the Phoenix cluster gathered by the Atacama Large Millimeter Array (ALMA), a collection of 66 large radio telescopes spread over the desert of northern Chile. 

The researchers believe that the new findings may help to explain the Phoenix cluster's exceptional star-producing power. 

They may also provide new insight into how supermassive black holes and their host galaxies mutually grow and evolve.

"With ALMA we can see that there's a direct link between these radio bubbles inflated by the supermassive black hole and the future fuel for galaxy growth," said study lead author Helen Russell, an astronomer with the University of Cambridge in Britain.

"This gives us new insights into how a black hole can regulate future star birth and how a galaxy can acquire additional material to fuel an active black hole," Russell said.

What the researchers believe to be happening is that, as jet inflate bubbles of hot gas near the black hole, they drag behind them a wake of slightly cooler gas. 

The bubbles eventually detach from the jets and float further out into the galaxy cluster, where each bubble's trail of gas cools, forming long filaments of extremely cold gas that condense and rain back onto the black hole as fuel for star formation.

"It's a very new idea that the bubbles and jets can actually influence the distribution of cold gas in any way," said study co-author Michael McDonald, an astrophysicist at the Massachusetts Institute of Technology in the US.

London, Feb 14 (IANS) A specific gene that plays a crucial role in ensuring DNA is copied correctly when cells divide and grow can cause growth defects associated with a rare type of dwarfism, says a study.

"This research sheds new light on the mechanisms underlying DNA replication, and the effect on human health when this process goes wrong," said Grant Stewart from University of Birmingham in Britain.

During the study, published today in Nature Genetics, the researchers looked at genetic information from more than 250 people around the world with microcephalic dwarfism, a group of disorders characterised by short stature and reduced head size.

They found that 29 of the individuals had faulty versions of a gene called DONSON.

Tests on cells growing in the laboratory revealed that this gene plays a crucial role in ensuring DNA is copied correctly when cells divide and grow.

Cells from patients with mutations in the DONSON gene had difficulty in efficiently replicating their DNA and protecting it from uncontrolled damage, ultimately leading to the growth defects typical of microcephalic dwarfism.

This research raises the potential of more accurate diagnoses for patients with genetic microcephaly, in addition to providing an insight into how similar rare hereditary diseases are caused.

Johannesburg, Feb 14 (IANS) A reptile related to early mammals was the first to produce venom in order to survive the rough conditions offered by the deadly South African environment 260 million years ago -- some 100 million years before the very first snake was even born -- a study says.

Computerised tomography (CT) scans of fossils of the dog-sized reptile, Therapsid Euchambersia, showed anatomical features, designed for venom production, according to the study published in the journal, PlosOne.

"Today, snakes are notorious for their venomous bite, but their fossil record vanishes in the depth of geological times at about 167 million years ago. So, at 260 million years ago, the Euchambersia evolved venom more than a 100 million years before the very first snake was even born, " said Julien Benoit from University of the Witwatersrand in South Africa.

As venom glands do not fossilise, Benoit and his colleagues at Wits University, in association with the Natural History Museum of London used CT scanning and 3D imagery techniques to analyse the only two fossilised skulls of the Euchambersia ever found, and discovered stunning anatomical adaptions that are compatible with venom production. 

"This is the first evidence of the oldest venomous vertebrate ever found, and what is even more surprising is that it is not in a species that we expected it to be," Benoit said.

The first Euchambersia fossil was found in 1932, and the second in 1966. According to measurements of the two fossils, the Euchambersia was a small dog-like pre-mammalian reptile that grew between 40 and 50 cm long.

"A wide, deep and circular fossa (a space in the skull) to accommodate a venom gland was present on the upper jaw and was connected to the canine and the mouth by a fine network of bony grooves and canals," Benoit said. 

"Moreover, we discovered previously undescribed teeth hidden in the vicinity of the bones and rock: two incisors with preserved crowns and a pair of large canines, that all had a sharp ridge. Such a ridged dentition would have helped the injection of venom inside a prey," Benoit explained.

New York, Feb 13 (IANS) Apple CEO Tim Cook has called for a crackdown on the epidemic of fake news and asked the governments to launch a public information campaign, media reports said.

According to a report in Telegraph, Cook said that fake news was 'killing people's minds' and necessitates a crackdown by the authorities and technology firms that would help providers of quality journalism and help drive out clickbait.

"The outcome of that is that truthful, reliable, non-sensational, deep news outlets will win," Cook was quoted as saying. 

To educate the people about the threat posed by fabricated online stories, Cook pitched for a campaign akin to those that changed public attitude towards environment. 

"We are going through this period of time right here where unfortunately some of the people that are winning are the people that spend their time trying to get the most clicks, not tell the most truth. It's killing people's minds in a way," Cook said.

He called on those tech firms which have not contributed much towards curbing the fake news, asking them to create tools that help diminish the volume of fake news.

"We must try to squeeze this without stepping on freedom of speech and of the press, but we must also help the reader. Too many of us are just in the complain category right now and have not figured out what to do," Cook added.

London, Feb 13 (IANS) Babies exposed to nicotine before and after birth may be at an increased risk of developing hearing problems due to abnormal development in the auditory brainstem, researchers have found.

The findings showed that the auditory brainstem -- an area of the brain which plays a role in analysing sound patterns -- may have abnormal development in kids when pregnant mothers are exposed to nicotine before and after giving birth. 

Children with impaired auditory brainstem function are likely to have learning difficulties and problems with language development.

"If mothers smoke during pregnancy and their children show learning difficulties at school, they should be tested for auditory processing deficits," said lead author Ursula Koch, professor at the Free University of Berlin in Germany. 

For the study, published in The Journal of Physiology, the team exposed the offspring of the mice to nicotine before birth and via the mother's milk until they were three weeks old -- an age that is approximately equivalent to primary school children. 

Analysing the brains of the mice offsprings, the researchers found that neurons that get input from the cochlea -- sensory organ in the ear -- were less effective at transmitting signals to other auditory brainstem neurons in mice exposed to nicotine.

Moreover, these signals were transmitted with less precision, which deteriorates the coding of sound patterns. These could be part of the underlying causes for auditory processing difficulties in children of heavy smoking mothers, the researchers said.

"We do not know how many other parts of the auditory system are affected by nicotine exposure. More research is needed about the cumulative effect of nicotine exposure and the molecular mechanisms of how nicotine influences the development of neurons in the auditory brainstem," Koch said.

Washington, Feb 13 (IANS) Researchers have used data from the European Space Agency's CryoSat-2 satellite to identify a sudden drainage of large pools below West Antarctica's Thwaites glacier, the media reported.

Thwaites Glacier, already one of the planet's fastest-moving glaciers, is sliding unstoppably into the ocean, mainly due to warmer seawater lapping at its underside, speeding up by about 10 per cent from June 2013 and January 2014, Xinhua news agency reported.

In a study published in The Cryosphere, the researchers from the University of Washington (UW) and the UK's University of Edinburgh reported finding four interconnected lakes drained during the eight-month period.

"This was a big event, and it confirms that the long-term speed-up that we're observing for this glacier is probably driven by other factors, most likely in the ocean," said corresponding author Ben Smith, a glaciologist with the UW's Applied Physics Laboratory, on Sunday. 

"The water flow at the bed is probably not controlling the speed."

The authors used a new technique to discover drops at the glacier's surface of up to 70 feet, over a 20 km by 40 km area.

Calculations show it was likely due to the emptying of four interconnected lakes far below. The peak drainage rate was about 240 cubic metres, per second, the largest melt-water outflow yet reported for subglacial lakes in this region.

The study supports previous UW research from 2014 showing that Thwaites glacier will likely collapse within 200 to 900 years to cause seas to rise by 2 feet. 

​Washington, Feb 13 (IANS) Scientists have shortlisted three landing sites for NASA's Mars 2020 rover -- slated for launch in July 2020 aboard an Atlas V 541 rocket from the Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida.

The three potential landing sites include Northeast Syrtis (a very ancient portion of Mars' surface), Jezero crater, (once home to an ancient Martian lake), and Columbia Hills (potentially home to an ancient hot spring and explored by NASA's Spirit rover).

The sites were recommended by participants in a landing site workshop, NASA said in a statement on Monday.

The rover will conduct geological assessments of its landing site on Mars, determine the habitability of the environment, search for signs of ancient Martian life, and assess natural resources and hazards for future human explorers. 

It will also prepare a collection of samples for possible return to the Earth by a future mission.

NASA's Jet Propulsion Laboratory (JPL) will manage operations of the Mars 2020 rover.

​New York, Feb 12 (IANS) Neurodegenerative diseases like Alzheimer's and Parkinson's may be linked to defective brain cells disposing toxic proteins, making neighbouring cells sick, scientists say.

The findings showed that although healthy neurons should be able to sort out and rid brain cells of toxic proteins and damaged cell structures, they are unable to do so always.

"Normally the process of throwing out this trash would be a good thing," said Monica Driscoll, professor at Rutgers University in New Jersey.

"But we think with neurodegenerative diseases like Alzheimer's and Parkinson's there might be a mismanagement of this very important process that is supposed to protect neurons but, instead, is doing harm to neighbour cells," Driscoll added, in the paper published in Nature.

To understand how the mechanism of eliminating toxic cellular substances works externally, the team conducted experiments on the transparent roundworm, known as the C. elegans, which are similar in molecular form, function and genetics to those of humans.

The researchers discovered that the worms -- which have a lifespan of about three weeks -- had an external garbage removal mechanism and were disposing these toxic proteins outside the cell as well.

However, the roundworms engineered to produce human disease proteins associated with Huntington's disease and Alzheimer's, were found to throw out more trash consisting of these neurodegenerative toxic materials.

While neighbouring cells degraded some of the material, more distant cells scavenged other portions of the diseased proteins.

"These finding are significant. The work in the little worm may open the door to much needed approaches to addressing neurodegeneration and diseases like Alzheimer's and Parkinson's," Driscoll said.

Washington, Feb 11 (IANS) Comet hunters have a chance to spot comet 45P/Honda-Mrkos-Pajdusakova in the next few days using binoculars or a telescope, NASA said on Saturday.

"It's the first of a trio of comets that will -- between now and the end of 2018 -- pass close enough to Earth for backyard observers to try to spot and for scientists to study using ground-based instruments," the US space agency said.

The recommendation for backyard astronomers is to use binoculars or a telescope to look for the comet several times during the coming days, NASA said.

Discovered in 1948, 45P is a short-period comet, with an orbit that takes it around the sun and out by Jupiter about every 5-1/4 years. 

This weekend's encounter will be the comet's closest with Earth - passing by at a distance of about 12.4 million kilometres -- through the end of this century.

The comet will pass by our planet again in 2032 but will be much farther away - at a distance of nearly about 48 million kilometres.

Scientists have taken advantage of 45P's approach, making observations using powerful ground-based telescopes such as NASA's Infrared Telescope Facility to investigate the gases, dust and ice particles that are released from the comet nucleus and show up in the coma and tail. 

By looking for water, methane and other important compounds, astronomers get clues about how the comet is put together and where it originated in the cloud of material that surrounded the young sun as the solar system formed.

By observing the same comet more than once, astronomers can see how the object changes over time.

"Observing a comet multiple times over successive orbits is like taking snapshots at different stages of life," said Joseph Nuth, a senior scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. 

NASA said ground-based observations also are planned for comet 41P/Tuttle-Giacobini-Kresak, which will pass closest to Earth on April 1, 2017, and for comet 46P/Wirtanen, passing closest to Earth on December 16, 2018. 

By studying this trio of comets, astronomers can learn more about the differences among comets -- information they use to fill in the comet family tree.

Kathmandu, Feb 11 (IANS) Nepal has recorded a new species of bird from upper Dolpa, the largest district of the mid-western development region.

Organising a press meet here on Friday, discovery of a single individual of Rufous-tailed Rock Thrush Monticola saxitilis was made public, Xinhua news agency reported. 

The bird was seen and photographed in May near the Shey monastery within the Shey-Phoksundo National Park of Dolpa.

The Rufous-tailed Rock Thrush is considered as an autumn passage migrant in Pakistan and India.

A four-member team including young wildlife researcher of Nepal Naresh Kusi and Geraldine Werhahn from University of Oxford made the record during their visit to the region.

The team was studying the Himalayan wol., wild yak and snow leopard while they discovered this new bird species.

Bird experts have claimed that more researches are needed to ascertain the status of Rufous-tailed Rock Thrush in other parts of Nepal.

With this record, Nepal now has a total of 886 species of birds.