Knowledge Update

New York, Feb 28 (IANS) Exoplanets with hydrogen pouring from volcanic sources may have a warmer surface and provide a better target for scientists to find signs of life outside our home planet, says a study.

"On frozen planets, any potential life would be buried under layers of ice, which would make it really hard to spot with telescopes," said lead author Ramses Ramirez from Cornell University in the US.

"But if the surface is warm enough -- thanks to volcanic hydrogen and atmospheric warming -- you could have life on the surface, generating a slew of detectable signatures," Ramirez said.

Combining the greenhouse warming effect from hydrogen, water and carbon dioxide on planets sprinkled throughout the cosmos, distant stars could expand their habitable zones by 30 to 60 per cent, according to this new research published in the Astrophysical Journal Letters.

"Where we thought you would only find icy wastelands, planets can be nice and warm - as long as volcanoes are in view," Lisa Kaltenegger, Professor at Cornell University, said. 

The idea that hydrogen can warm a planet is not new, but an Earth-like planet cannot hold onto its hydrogen for more than a few million years. Volcanoes change the concept. 

"You get a nice big warming effect from volcanic hydrogen, which is sustainable as long as the volcanoes are intense enough," said Ramirez, who suggested the possibility that these planets may sustain detectable life on their surface.

A very light gas, hydrogen also "puffs up" planetary atmospheres, which will likely help scientists detect signs of life. 

"Adding hydrogen to the air of an exoplanet is a good thing if you're an astronomer trying to observe potential life from a telescope or a space mission. It increases your signal, making it easier to spot the makeup of the atmosphere as compared to planets without hydrogen," Ramirez said.

In our solar system, the habitable zone extends to 1.67 times the Earth-sun distance, just beyond the orbit of Mars. 

With volcanically sourced hydrogen on planets, this could extend the solar system's habitable zone reach to 2.4 times the Earth-sun distance -- about where the asteroid belt is located between Mars and Jupiter. 

This research places a lot of planets that scientists previously thought to be too cold to support detectable life back into play.

"We just increased the width of the habitable zone by about half, adding a lot more planets to our 'search here' target list," Ramirez said.

​London, Feb 28 (IANS) If you are using a pacemaker to regulate your heartbeat, be careful about the proximity to your body of everyday household appliances and electrical tools as these may affect the functioning of the device, warns new research.

A pacemaker is a small device that is placed in the chest or abdomen to help control abnormal heart rhythms. This device uses low-energy electrical pulses to prompt the heart to beat at a normal rate and is used to treat problems relating to the rate or rhythm of the heartbeat.

The findings showed that pacemakers are susceptible to electric and magnetic fields (EMF) generated from powerlines, household appliances, electrical tools and entertainment electronics, in particular when programmed to maximum sensitivity or so-called unipolar sensing mode. 

This EMF interference, depending on factors such as the settings of the implant or strength of the field source with pacemakers, can result in bradycardia, or a slow heart rate. 

"Electromagnetic interferences with pacemakers in everyday life can cause harmful interferences," said Andreas Napp, cardiologist at RWTH Aachen University Hospital in Germany.

In many cases, holding the appliance, tool or other EMF source at a forearm's length distance -- greater than 12 inches -- limits the risk of electromagnetic interference. 

Thus, "in occupational environments, such as the manufacturing industry, an individual risk assessment for workers with a pacemaker is required due to the presence of a strong EMF," Napp added, in the paper appearing in the journal Circulation.

However, using dedicated device programming can effectively measure to reduce the individual risk of interference. For example, doctors can reprogramme pacemakers to a lower sensitivity to reduce EMF susceptibility, Napp said.

For the study, the team tested under different conditions the impacts of EMF exposure on 119 patients with pacemakers.

New York, Feb 28 (IANS) Dogs and two-year-old children show similar patterns in social intelligence, much more than one of our closest relatives -- chimpanzees, says a study.

The researchers looked at how two-year-olds, dogs and chimpanzees performed on comparable tests designed to measure various types of cognition. 

While chimpanzees performed well on tests involving their physical environment and spatial reasoning, they did not do as well when it came to tests of cooperative communication skills, such as the ability to follow a pointing finger or human gaze.

Dogs and children outperformed chimpanzees on cooperative communication tasks, and researchers observed similar patterns of variation in performance between individual dogs and between individual children.

"What we found is that there's this pattern, where dogs who are good at one of these social things tend to be good at lots of the related social things, and that's the same thing you find in kids, but you don't find it in chimpanzees," said Evan MacLean, Director of the Arizona Canine Cognition Center at the University of Arizona in the US.

The findings, published in the journal Animal Behaviour, could help scientists better understand how humans evolved socially.

One explanation for the similarities between dogs and humans is that the two species may have evolved under similar pressures that favoured "survival of the friendliest", with benefits and rewards for more cooperative social behaviour.

"Our working hypothesis is that dogs and humans probably evolved some of these skills as a result of similar evolutionary processes, so probably some things that happened in human evolution were very similar to processes that happened in dog domestication," MacLean said. 

"So, potentially, by studying dogs and domestication we can learn something about human evolution," he added.

The research could even have the potential to help researchers better understand human disabilities, such as autism, that may involve deficits in social skills, MacLean said.

New York, Feb 28 (IANS) Shortly after te Earth formed and began to cool, the planet's first outer layer was a single, solid but deformable shell which later began to fold and crack more widely, giving rise to modern plate tectonics, suggests new research.

The research is the latest salvo in a long-standing debate in the geological research community: Did plate tectonics start right away -- a theory known as uniformitarianism, or did the Earth first go through a long phase with a solid shell covering the entire planet? 

"Models for how the first continental crust formed generally fall into two groups: Those that invoke modern-style plate tectonics and those that do not," said study co-author Michael Brown, Professor at the University of Maryland in the US. 

"Our research supports the latter -- a 'stagnant lid' forming the planet's outer shell early in Earth's history," Brown said.

Today's Earth is a dynamic planet with an outer layer composed of giant plates that grind together, sliding past or dipping beneath one another, giving rise to earthquakes and volcanoes. 

Others separate at undersea mountain ridges, where molten rock spreads out from the centers of major ocean basins.

The new research, published in the journal Nature, suggests that plate tectonics began later in the Earth's history.

To reach these conclusions, Brown and his colleagues from Curtin University and the Geological Survey of Western Australia studied rocks collected from the East Pilbara Terrane, a large area of ancient granitic crust located in the state of Western Australia. 

The area is known for having some of the oldest known rocks, ranging from 3.5 to about 2.5 billion years of age. The Earth is roughly 4.5 billion years old.

The researchers specifically selected granites with a chemical composition usually associated with volcanic arcs -- a telltale sign of plate tectonic activity.

Based on their analysis, the researchers concluded that the Earth probably began with a solid outer shell.

"We conclude that a multi-stage process produced Earth's first continents in a 'stagnant lid' scenario before plate tectonics began," Brown said.

​London, Feb 28 (IANS) In a first, researchers have found evidence of planetary debris surrounding a double sun that resembles Tatooine -- Luke Skywalker's home world in the "Star Wars" film.

A scene in "Star Wars", where Skywalker looks at the horizon with the setting of two suns is regarded as one of the most iconic images in cinema.

In a study published in the journal Nature Astronomy, the researchers described the remains of shattered asteroids orbiting a double sun consisting of a white dwarf and a brown dwarf roughly 1000 light-years away in a system called SDSS 1557.

The debris appears to be rocky and suggests that terrestrial planets like Tatooine might exist in the system, according to the researchers.

"With the discovery of asteroid debris in the SDSS 1557 system, we see clear signatures of rocky planet assembly via large asteroids that formed, helping us understand how rocky exoplanets are made in double star systems," said lead study author Jay Farihi from University College London.

To date, all exoplanets discovered in orbit around double stars are gas giants, similar to Jupiter, and are thought to form in the icy regions of their systems.

In contrast to the carbon-rich icy material found in other double star systems, the planetary material identified in the SDSS 1557 system has a high metal content, including silicon and magnesium. 

These elements were identified as the debris flowed from its orbit onto the surface of the star, polluting it temporarily with at least 1.1 trillion tonnes of matter, equating it to an asteroid at least four km in size.

"Building rocky planets around two suns is a challenge because the gravity of both stars can push and pull tremendously, preventing bits of rock and dust from sticking together and growing into full-fledged planets," Farihi said.

The team studied the binary system and the chemical composition of the debris by measuring the absorption of different wavelengths of light or 'spectra', using the Gemini Observatory South telescope and the European Southern Observatory Very Large Telescope, both located in Chile.

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New Delhi, Feb 27 (IANS) The WHO on Monday said it it has published the first-ever list of antibiotic-resistant "priority pathogens", 12 families of bacteria that pose the greatest threat to human health, to guide and promote research and development of new antibiotics.

The Geneva-based World Health Organisation (WHO) said that list was drawn up as part of its efforts to address growing global resistance to antimicrobial medicines.

According to the global health body, the list is divided into three categories according to the urgency of need for new antibiotics: critical, high and medium priority.

"The most critical group of all includes multi-drug resistant bacteria that pose a particular threat in hospitals, nursing homes, and among patients whose care requires devices such as ventilators and blood catheters. They include Acinetobacter, Pseudomonas and various Enterobacteriaceae (including Klebsiella, E. coli, Serratia, and Proteus)," said a WHO statement.

It said that all the bacteria can cause severe and often deadly infections such as bloodstream infections and pneumonia.

"These bacteria have become resistant to a large number of antibiotics, including carbapenems and third generation cephalosporins - the best available antibiotics for treating multi-drug resistant bacteria," said the report.

The second tier which includes antibiotics of high priority includes for Enterococcus faecium, which is vancomycin-resistant, Staphylococcus aureus which is methicillin-resistant, Helicobacter pylori which is clarithromycin-resistant, Campylobacter spp which is fluoroquinolone-resistant, Salmonellae which is fluoroquinolone-resistant, Neisseria gonorrhoeae which is cephalosporin and fluoroquinolone-resistant.

The third tier which includes medium priority includes Streptococcus pneumoniae which is penicillin-non-susceptible, Haemophilus influenzae, which is ampicillin-resistant and Shigella spp which is fluoroquinolone-resistant.

"This list is a new tool to ensure research and development responds to urgent public health needs," said WHO's Assistant Director-General for Health Systems and Innovation Marie-Paule Kieny in the statement.

Evelina Tacconelli, Head of the Division of Infectious Diseases at the University of Tübingen and a major contributor to the list, said :"New antibiotics targeting this priority list of pathogens will help to reduce deaths due to resistant infections around the world. 

"Waiting any longer will cause further public health problems and dramatically impact on patient care."

New York, Feb 26 (IANS) Although the last Neanderthal died tens of thousands years ago, their DNA sequences still influence how genes are turned on or off in modern humans, and their effects can contribute to traits such as height and susceptibility to schizophrenia or lupus, says a study.

Experts know that after leaving Africa, our ancestors -- the homo sapiens -- mated with Neanderthals thousands of years ago, and today Neanderthal DNA makes up one to four per cent of the genomes of modern non-African people. 

"Even 50,000 years after the last human-Neanderthal mating, we can still see measurable impacts on gene expression," said study co-author Joshua Akey from the University of Washington School of Medicine in Seattle.

"And those variations in gene expression contribute to human phenotypic variation and disease susceptibility," Akey added.

Previous studies have found correlations between Neanderthal genes and traits such as fat metabolism, depression, and lupus risk.

In this study, published in the journal Cell, researchers analysed RNA sequences in a dataset called the Genotype-Tissue Expression (GTEx) Project, looking for people who carried both Neanderthal and modern human versions of any given gene -- one version from each parent. 

For each such gene, the investigators then compared expression of the two alleles head-to-head in 52 different tissues.

"We find that for about 25 per cent of all those sites that we tested, we can detect a difference in expression between the Neanderthal allele and the modern human allele," added Rajiv McCoy, post-doctoral researcher at the University of Washington.

One example uncovered by this study is a Neanderthal allele of a gene called ADAMTSL3 that decreases risk of schizophrenia, while also influencing height.

"Hybridisation between modern humans and Neanderthals increased genomic complexity," Akey explained.

"Hybridisation wasn't just something that happened 50,000 years ago that we don't have to worry about anymore. Those little bits and pieces, our Neanderthal relics, are influencing gene expression in pervasive and important ways," Akey said.

New York, Feb 25 (IANS) Researchers have found a 700-per cent surge in infections caused by bacteria that is resistant to multiple kinds of antibiotics among children in the US.

According to researchers, these antibiotic resistant infections -- caused by Enterobacteriaceae, a family of bacteria that also include such pathogens as Salmonella and Escherichia coli -- are linked to longer hospital stays and potentially greater risk of death.

The findings showed that the proportion of these infections in children caused by bacteria increased from 0.2 per cent in 2007 to 1.5 per cent in 2015, a more than 700 per cent increase in prevalence over the eight-year period.

"There is a clear and alarming upswing throughout US of antibiotic resistant Enterobacteriaceae infections in kids and teenagers," said lead author Sharon B. Meropol, a pediatrician and epidemiologist at Case Western Reserve University in the US. 

Bacterial infections resistant to multiple drugs are especially concerning in children, for whom there are a limited number of stronger antibiotics currently approved for use compared to adults, putting kids at higher risk for worse outcomes, the researchers said. 

For the study, published in the Journal of the Pediatric Infectious Diseases Society, the team analysed data from 48 children's hospitals throughout the US, focusing on approximately 94,000 patients under the age of 18 who were diagnosed with Enterobacteriaceae - associated infections between 2007 and 2015. 

More than 75 per cent of the antibiotic-resistant infections were already present when the young people were admitted to the hospital, upending previous findings that the infections were mostly picked up in the hospital. 

This suggested that the bacteria may be increasingly spreading in the community. 

In addition, the bacterial infection may also cause a greater mortality risk among pediatric patients.

"Health care providers have to make sure we only prescribe antibiotics when they're really needed. It's also essential to stop using antibiotics in healthy agricultural animals", Meropol added.