Knowledge Update

​New York, July 9 (IANS) Scientists may finally have an explanation for why some galaxies stop creating stars after a team of astrophysicists painstakingly analysed around 70,000 galaxies to understand the forces influencing star formation activity in them.

The international research team, led by researchers from the University of California, Riverside, combed through available data from the COSMOS UltraVISTA survey that give accurate distance estimates for galaxies over the past 11 billion years, and focused on the effects of external and internal processes that influence star creation in galaxies.

The processes that cause galaxies to "quench", that is, cease star formation, are not well understood and constitute an outstanding problem in the study of the evolution of galaxies. 

"By using the observable properties of the galaxies and sophisticated statistical methods, we show that, on average, external processes are only relevant to quenching galaxies during the last eight billion years," said study lead author Behnam Darvish from the University of California.

"On the other hand, internal processes are the dominant mechanism for shutting off star-formation before this time, and closer to the beginning of the universe," he added.

External processes include drag generated from an infalling galaxy within a cluster of galaxies, multiple gravitational encounters with other galaxies and the dense surrounding environment and the halting of the supply of cold gas to the galaxy.

Internal mechanisms include the presence of a black hole and "stellar outflow" (for example, high-velocity winds produced by massive young stars and supernovae that push the gas out of the host galaxy).

The finding, published recently in the Astrophysical Journal, gives astronomers an important clue towards understanding which process dominates quenching at various cosmic times. 

As astronomers detect quenched non-star-forming galaxies at different distances (and therefore times after the Big Bang), they now can more easily pinpoint what quenching mechanism was at work.​

​London, July 10 (IANS) Immunotherapy has the potential to reduce the risk of heart disease in patients suffering with rheumatoid arthritis, finds a study.

Rheumatoid arthritis is an autoimmune disease in which cytokines such as tumour necrosis factor-alpha (TNFI) and interfero-gamma (IFN), which normally protect the body, attack healthy cells

The findings showed that the combination of two anticytokines containing extra-low doses of antibodies against TNFI and IFN could improve the efficacy of standard rheumatoid arthritis therapy and decrease heart disease risk.

"In rheumatoid arthritis, patients have painful and inflamed joints. They are also at increased cardiovascular risk, particularly if their rheumatoid arthritis is not controlled," said Aida Babaeva, Professor at Volgograd State Medical University in Russia.

Further, the patients taking the combination of anticytokines had a lower rheumatoid arthritis disease activity score, as measured by the DAS28,2 and more dramatic decreases in IL-1, IL-6 and TNF alpha than the group on standard therapy alone.

The incidence of cardiovascular events (unstable angina, severe hypertensive crisis, and deterioration of chronic heart failure) was more than double in the group on conventional disease-modifying drugs alone (37 per cent) compared to those also taking the combination of anticytokines (13 per cent).

"Our findings suggest that the decreased rheumatoid arthritis disease activity with the combination of anticytokines translates into decreased cardiovascular risk," Babaeva said.

Rheumatoid arthritis is also associated with dysfunction of the blood vessel lining (called endothelium), which leads to lipid accumulation in the artery wall, plaque formation and atherosclerosis.

"Thus, decreasing disease activity may also reduce cardiovascular risk by slowing down or halting these processes," Babaeva added.

For the study, the team included 68 patients who had suffered from active rheumatoid arthritis for at least five years.

Patients were randomised to receive the combination of anti-TNF alpha and anti-IFN gamma plus standard disease-modifying therapy (38 patients) or placebo plus standard therapy (30 patients).

We recommend this new approach for preventing cardiovascular events in patients with moderate disease activity who are not receiving the standard biologics and who do not have severe complications."

The research was presented at the Frontiers in CardioVascular Biology (FCVB) 2016 in Italy, recently.​

​London, July 10 (IANS) Humans and other terrestrial animals learn how to walk in similar ways, finds an interesting study.

"We look at the emergence of walking behaviours in both human babies and infant animals, as they develop," said lead author Nadia Dominici from VU University in Netherlands.

Movements such as walking are created from the flexible combination of a small set of groups of muscles that simplify the control of locomotion, called "locomotor primitives".

The findings showed that human babies are born with just two walking primitives: the first directs the legs to bend and extend; the second commands the baby's legs to alternate -- left, right, left, right -- in order to move forward.

To walk independently, babies learn two more primitives, which is to handle balance control -- step timing and weight shifting.

These primitives are unexpectedly alike across different animals -- including rats that the study explored.

"Despite all of the differences in body structure and evolution, locomotion in several animal species could start from common primitives, maybe even stemming from a common ancestral neural network," Dominici added.

Babies are born with an instinct for walking and these are reflected when the child is held near to the floor.

The primitive stepping reflex displayed by the child shows the natural "walking" instinct, which becomes the foundation on which children build an independent walking motion, said the paper.

Understanding these first steps can improve the rehabilitation of patients recovering from spinal cord injury, and children with cerebral palsy, the researchers concluded.​

​London, July 10 (IANS) Norwegian researchers have ventured to delve into why people tend to perceive affinities between sound and body motion when experiencing music -- and agreed that it is all rooted in human cognition.

Researchers from the University of Oslo explored the theory behind the relationship between musical sound and body movement -- the so-called 'motor theory of perception'. 

They explored the relationship between musical sound and body movement -- and came up with results that showed these similarity relationships are deeply rooted in human cognition. 

The results indicated a fair amount of similarity among the participants' gestures, particularly between the vertical positioning of their hands and the pitch of the sound, according to the study published by the Journal of New Music Research.

For the study, the participants were played three-second sounds that varied in pitch and other musical qualities and were asked to trace the sounds in the air using motion capture technology. 

"Music-related motion -- both sound producing and sound accompanying -- leaves a trace in our minds and could be thought of as a kind of shape representation, one intimately linked to our experience of the salient features of musical sound," said Professor Rolf Inge Godoy of the University of Oslo.

In general, some sound features such as rhythm and texture seem to be strongly related to movement while others, such as dissonance, have a weaker sound-motion relationship. 

As a result, the researchers intend to focus their future work on researching large-scale statistical sound-motion feature correlations, providing us with more data on sound-motion similarity relationships in all kinds of musical experience.

"The basic notion here is that images of sound-producing and other sound-related motion are actively re-created in listening and in musical imagery, hence the idea that motor theory could be the basis for the similarities between sound and body movement when we experience music,” added Godoy.

Although links between musical sound and motion can be readily observed, the researchers argue that a more systematic knowledge of them is required.

In order to perceive something, one must actively simulate the motion associated with the sensory impressions.

So, when one listens to music, the person tends to mentally simulate the body movements that have gone into producing the sound. Thus the experience of a sound entails a mental image of a body motion.​

​Ottawa, July 10 (IANS) Coffee lovers who like to attend rock music concerts or work at airports should be cautious as a recent study indicates that caffeine has a serious impact on hearing.

According to a research by the McGill University in Canada, regular caffeine consumption can greatly impede hearing recovery from loud noise, even making the damage permanent, Xinhua news agency reported.

"When the ear is exposed to loud noise, it can suffer from a temporary hearing reduction, also called auditory temporary threshold shift. This disorder is usually reversible in the first 72 hours after the exposure, but if symptoms persist, the damage could become permanent," said Dr Faisal Zawawi, an otolaryngologist at McGill.

The researchers found this impact through an experiment on guinea pigs. They grouped the pigs and tested them in environments of noise without coffee, and noise with coffee.

The noise the animals were exposed to for one hour per day is similar as what people hear at a rock concert. After eight days, significant difference of hearing loss is recorded between the two groups, according to the research team.

In 2015, the European Food Safety Authority published an advice that caffeine intakes from all sources up to 400 mg per day and single doses of 200 mg might be safe for adults in the general population.

But the McGill research suggests that exposure to loud noises coupled with daily consumption of 25 mg of caffeine may have a clear negative impact on hearing recovery.​

New York, July 8 (IANS) A study of numerous seasonal dark streaks called "recurring slope lineae" or RSLs found at a canyon network on Mars has offered important clues that liquid water could be present on the Red Planet.

Water pulled from the atmosphere by salts, or mechanisms with no flowing water involved, remain possible explanations for the occurrence of RSLs in part of the Valles Marineris region near Mars' equator.

"There are so many of them, it's hard to keep track," said study led author Matthew Chojnacki from the University of Arizona.

"The occurrence of recurring slope lineae in these canyons is much more widespread than previously recognised. As far as we can tell, this is the densest population of them on the planet, so if they are indeed associated with contemporary aqueous activity, that makes this canyon system an even more interesting area than it is just from the spectacular geology alone," he added.

The team examined the geological context of canyonland RSL sites and also calculated how much water would need to be present if the streaks are due to liquid water seeping through a thin surface layer to darken the ground.

Many of the sites where RSLs were previously identified are on inner walls of impact craters. At that type of site, a conceivable explanation could be that an extensive underground layer holding water was punctured by the crater-forming impact long ago and still feeds warm-season flows.

If it is seeping water that darkens RSLs, the amount of liquid water required each year to form the streaks in the studied portion of Valles Marineris would total about 10 to 40 Olympic-size swimming pools (about 30,000 to 100,000 cubic metres), the researchers estimate. 

However, no such underground layer fits the ridge or peak shapes at several of the RSL sites in the new study.

Another possible mechanism previously proposed for RSLs is that some types of salts so strongly pull water vapour out of the Martian atmosphere that liquid brine forms at the ground surface. 

The new study results, reported recently by NASA, bolsters the link between RSL and salts. Some sites bear bright, persistent streaks near the dark, seasonal ones. The bright streaks might result from salt left behind after evaporation of brine.

"There do seem to be more ways atmosphere and surface interact in the canyons than in blander topography, such as clouds trailing out of the canyons and low-lying haze in the canyons," Chojnacki said.

Another factor added by the new study is that RSLs not only darken the surface, but are also associated with material moving downslope. The research documents slumping and other three-dimensional changes at some RSL sites, occurring seasonally in tandem with the streaks.​

New York, July 8 (IANS) A team of astronomers has discovered a strange world with its three suns in the sky, witnessing either constant daylight or triple sunrises and sunsets each day depending on the seasons that may last longer than human lifetimes.

Using direct imaging, the team led by the University of Arizona researchers found that the giant planet HD 131399Ab is unlike any other known world with the widest known orbit within a multi-star system. 

Located about 340 light years from Earth in the constellation Centaurus, HD 131399Ab is believed to be about 16 million years old, making it one of the youngest exoplanets discovered to date. 

"HD 131399Ab is one of the few exoplanets that have been directly imaged, and it's the first one in such an interesting dynamical configuration," said Daniel Apai from the University of Arizona. 

According to study lead author Kevin Wagner, a doctoral student in Apai's research group, for about half of the planet’s orbit, which lasts 550 Earth-years, three stars are visible in the sky, the fainter two always much closer together, and changing in apparent separation from the brightest star throughout the year.

"For much of the planet’s year the stars appear close together, giving it a familiar night-side and day-side with a unique triple-sunset and sunrise each day," Wagner said.

"As the planet orbits and the stars grow farther apart each day, they reach a point where the setting of one coincides with the rising of the other - at which point the planet is in near-constant daytime for about one-quarter of its orbit, or roughly 140 Earth-years," he added.

The study was recently published in the journal Science.

The researchers used the Spectro-Polarimetric High-Contrast Exoplanet Research Instrument (SPHERE) installed on the Very Large Telescope operated by the European Southern Observatory in Chile to make the discovery.

Planets in multi-star systems are of special interest to astronomers and planetary scientists because they provide an example of how planet formation functions in these extreme scenarios. 

While multi-star systems seem exotic to us in our orbit around our solitary star - multi-star systems are in fact just as common as single stars.​

​London, July 9 (IANS) Living near the highway could cost your heart dear as researchers have found that risk of heart attack goes up with the amount of traffic noise to which you are exposed.

The increase in risk - though slight - is greatest with road and rail traffic noise, less with aircraft noise, researchers said.

For the study Andreas Seidler from Germany's Dresden University of Technology and his co-authors evaluated information from statutory health insurers on over a million Germans over the age of 40.

In this case-control study of secondary data, the addresses of persons living in the Rhine-Main region were matched precisely to road, rail, and traffic noise exposure measurements for 2005. 

When the analysis was restricted to patients who died of heart attack up to 2014/2015, a statistically significant association was found between noise exposure and the risk of heart attack. 

The authors believe the lower risk from aircraft noise can be explained by the fact that, unlike road and rail traffic noise, aircraft noise never remains continuously above 65 dB (decibel). 

They also see indications from their analysis that exposure to traffic noise influences not just the genesis, but the course of a heart attack.

The findings appeared in the journal Deutsches Arzteblatt International.

Although strictly speaking these results show only an association between traffic noise and heart attack, the authors believe that the sheer numbers of people affected by noise pollution mean that it is now right to start intensive efforts towards effective prevention of traffic noise. 

This study is part of the Europe-wide NORAH (Noise-Related Annoyance, Cognition, and Health) study investigating the health consequences of traffic noise.​

​London, July 9 (IANS) A team of scientists has demonstrated how the natural movement of bacteria could be harnessed to assemble and power microscopic 'windfarms' - or other man-made micro-machines such as smartphone components.

Using computer simulations, the scientists from Oxford University demonstrated that the chaotic swarming effect of dense active matter such as bacteria can be organised to turn cylindrical rotors and provide a steady power source. 

"Many of society's energy challenges are on the gigawatt scale, but some are downright microscopic. One potential way to generate tiny amounts of power for micromachines might be to harvest it directly from biological systems such as bacteria suspensions," said study co-author Tyler Shendruk.

The study results were published recently in the journal 'Science Advances'.

Swimming bacteria are normally too disordered to extract any useful power from. But when the team immersed a lattice of 64 symmetric microrotors into a dense bacterial suspension, the bacteria spontaneously organised itself in such a way that neighbouring rotors began to spin in opposite directions - a simple structural organisation reminiscent of a windfarm.

"The amazing thing is that we didn't have to pre-design microscopic gear-shaped turbines. The rotors just self-assembled into a sort of bacterial windfarm," Shendruk said.

"When we did the simulation with a single rotor in the bacterial turbulence, it just got kicked around randomly. But when we put an array of rotors in the living fluid, they suddenly formed a regular pattern, with neighbouring rotors spinning in opposite directions," he added.

At micro scales, the simulations show that the flow generated by biological assemblies is capable of reorganising itself in such a way as to generate a persistent mechanical power for rotating an array of microrotors, which could be harnessed to power micro-machines​

​New York, July 9 (IANS) Researchers have discovered a new gene that controls blood vessel formation -- presenting a possible new drug target for cancer and heart disease.

The joint team from Duke-NUS Medical School (Duke-NUS) and the National Heart Centre Singapore (NHCS) uncovered a role for the gene, Wars2, in the process of angiogenesis - a process controlling formation of a network of blood vessels that enables the body to deliver the nutrients necessary to keep the tissues and organs alive and healthy.

"Using different genetic techniques, we inhibited Wars2 function in both rats and zebrafish, and the resulting animals showed impairment of blood vessel formation within the heart and in the rest of the body," said Mao Wang from Duke-NUS, the co-first author of the study.

To confirm the involvement of Wars2 in angiogenesis, the researchers increased the effect of Wars2 and showed that blood vessel formation was enhanced. 

Specifically, they were able to determine that Wars2 plays an important role in supplying sufficient endothelial cells, the building blocks of blood vessels, for angiogenesis, according to the study published recently in the journal Nature Communications.

"Finding a way to control angiogenesis not only provides a target for the development of anti-cancer therapies, but may also prove useful in similarly starving abnormal blood vessel growth elsewhere in the body, like in diabetic eye disease," said Stuart Cook of Duke-NUS.​