Knowledge Update

​London, March 19 (IANS) Researchers have found that the blue tit, collared flycatcher and pied flycatcher have the fastest eyesight in the animal kingdom, with their vision being more than twice as fast as humans.

Thought to be the fastest of any vertebrate animal, their remarkable vision system, allows them to see the world around them in slow motion.

“Bird species similar to the blue tit, collared flycatcher and pied flycatcher, both ecologically and physiologically, probably also share the faculty of superfast vision,” said lead researcher Anders Ödeen, lecturer at Uppsala University in Sweden.

The study, published in the journal PLOS ONE, showed that perching birds, or passerines, have eyes with a temporal visual resolution -- precision of a measurement with respect to time -- of up to 146Hz.

It is at least 50Hz faster than any other vertebrate, and well over twice as fast as the 60Hz a human eye can detect, the researchers pointed out adding that this indicates an evolutionary history of natural selection for fast vision in these bird species. 

That the small airborne birds need to detect and track objects whose image moves very swiftly across the retina to be able to see and avoid all branches when they take cover from predators by flying straight into bushes, gives an explanation for their fast vision. 

The findings raise concerns about the welfare of small caged birds, especially those kept in areas with modern low-energy or flickering lighting light, which can cause stress, behavioural disturbances and various forms of discomfort in humans and birds alike.

Yet it appears perching birds may have traded their ultra-sharp vision at the expense of sharpness.

While the record for the sharpest vision still rests with eagles, which can detect finer details than any other animal, perching birds can only see in low resolution.

For the study, the team trained wild-caught birds to receive a food reward by distinguishing between a pair of lamps, one flickering and one shining a constant light. 

Temporal resolution was then determined by increasing the flicker rate to a threshold at which the birds could no longer tell the lamps apart. 

These birds are increasingly often kept in rooms lit with low-energy light bulbs, fluorescent lamps or LED lighting. Many of these flicker at 100 Hz, which is invisible to humans but perhaps not to small birds in captivity.

​New York, March 18 (IANS) Ever wondered how your working memory functions in the brain? A new study finds that bursts of neural activity take place as the brain holds information in mind.When the mind holds a sentence just read or a phone number that one is about to dial, then the individual is engaging a critical brain system known as working memory.
The new study upends the notion that brain cells associated with information fire continuously and instead reveals that as information is held in working memory, neurons -- nerve cells -- fire in sporadic and coordinated bursts."Your brain operates in a very sporadic, periodic way, with lots of gaps in between the information the brain represents," said one of the lead authors Mikael Lundqvist, postdoctoral researcher at the Massachusetts Institute Of Technology (MIT) in the US.

Our brain actually works in a very periodic fashion, sending packets of information around.These cyclical bursts could help the brain to hold multiple items in working memory at the same time, the researchers explained."By having these different bursts coming at different moments in time, you can keep different items in memory separate from one another," added one of the authors Earl Miller, professor at MIT.
It would be worthwhile to look for this kind of cyclical activity in other cognitive functions such as attention, the researchers suggested in the study, published in the journal Neuron.The team recorded neuron activity in animals as they were shown a sequence of three coloured squares, each in a different location. 

Then, the squares were shown again, but one of them had changed colour. The animals were trained to respond when they noticed the square that had changed colour -- a task requiring them to hold all three squares in working memory for about two seconds.

The researchers found that as the items were held in working memory, ensembles of neurons in the prefrontal cortex were active in brief bursts, and these bursts only occurred in recording sites in which information about the squares was stored. The bursting was most frequent at the beginning of the task, when the information was encoded, and at the end, when the memories were read out.​

​Toronto, March 18 (IANS) Some baby monkeys develop faster than others in the same population, and this is best explained by the threat of infanticide they face from adult males, says a study.

"Infanticide occurs in many animals, including carnivores like lions and bears, rodents like mice, and in primates," said lead researcher Iulia Badescu from University of Toronto."Typically, an adult male kills an infant sired by another male so that he can mate with the mother and sire his own infants with her," Badescu noted.
In this study that appeared online in the journal Animal Behaviour, the researchers looked at infant development in wild ursine colobus monkeys. Black-and-white colobus includes several species of medium-sized monkeys found throughout equatorial Africa. 
They have black bodies with white hair that sometimes forms a bushy white beard and sideburns, or can extend down the back like a 'cape' and down the tail.
Colobus babies are born pure white and their coat colour changes to grey after a few weeks before turning black-and-white between two and five months. The researchers were intrigued by the fact that infants varied in the age at which their coats became grey, and then black and white. 

They also realised that these colour transitions were helpful to track the development of the infants, in a non-intrusive fashion.Earlier research at the study site, Boabeng-Fiema Monkey Sanctuary in Ghana, established that some scenarios are more likely to lead to infanticide by males. Groups with multiple males, for example, have more instances of infanticide.

The team observed nine groups of ursine colobus monkeys in the wild over a period of eight years (2007 to 2014). 
"We found that infants facing a greater risk of infanticide developed faster than infants facing lesser risk," Pascale Sicotte, professor at University of Calgary in Canada, explained.​

Tokyo, March 16 (IANS) To understand the effects of microgravity on crystal growth, a team of Japanese researchers has measured the growth of crystals in a specially-designed chamber on board the International Space Station (ISS).
The researchers monitored the very slow growth and dissolution rate -- approximately one centimetre per second of the crystals by a method called laser interferometry.

This was the first time the technique had been used onboard the orbiting international laboratory to measure the growth rate of the crystals at various temperatures.

“We are interested in the growth mechanisms of a space-grown protein crystal -- a lysozyme crystal -- as a model crystal to understand why space-grown crystals sometimes do show better quality than the Earth-grown crystals," explained Tomoya Yamazaki, PhD student in Katsuo Tsukamoto's lab in Tohoku University's department of earth and planetary science in Sendai, Japan.

To observe this, Yamazaki and his colleagues developed unique growth cells suitable for long-term projects for about six months.

For the researchers studying protein crystal growth, that distance was 250 miles up -- the altitude at which the ISS orbits the Earth.

The experimental process, known as NanoStep, was performed in the Japanese Experimental Module (KIBO) of the ISS.

Tsukamoto and his colleagues had previously measured the growth rates of protein crystals under simulated microgravity by using a Russian recoverable satellite and aircraft in parabolic flights.

The researchers took precise measurements of the growth rate of the lysozyme crystals versus their driving force and supersaturation. This also yielded crucial information about the growth mechanism.

Tsukamoto and his colleagues detailed the growth method in the journal Review of Scientific Instruments.

While the researchers expected growth rates of the crystal solution to be slower because of the suppression of solution convection, the results instead showed an increased growth rate.

Extended projects for the researchers using the same apparatus to test the growth of different crystals, such as glucose isomerase crystals, are currently in preparation.​

​New York, March 15 (IANS) Forget the toxic material lithium as researchers from the Massachusetts Institute of Technology (MIT) have come up with an alternative system for generating electricity which harnesses heat and uses no metals or toxic materials for powering smartphones or cars, even deep space missions.

The new approach is based on a discovery announced in 2010 by Michael Strano, the Carbon P. Dubbs professor in chemical engineering at the MIT, and his co-workers.

A wire made from tiny cylinders of carbon known as carbon nanotubes can produce an electrical current when it is progressively heated from one end to the other, for example, by coating it with a combustible material and then lighting one end to let it burn like a fuse.

Now, Strano and his team have increased the efficiency of the process more than a thousandfold and have produced devices that can put out power that can be produced by today's best batteries. 

The researchers, however, caution that it could take some years to develop the concept into a commercialisable product.

“It's actually remarkable that this [phenomenon] hasn't been studied before. The latest experiments show good agreement between theory and experimental results, providing strong confirmation of the underlying mechanism,” said Strano in a paper published in the journal Energy & Environmental Science.

Already, the device is powerful enough to show that it can power simple electronic devices such as an LED light. 

Unlike batteries that can gradually lose power if they are stored for long periods, the new system should have a virtually indefinite shelf life. 

That could make it suitable for uses such as a deep-space probe that remains dormant for many years as it travels to a distant planet and then needs a quick burst of power to send back data when it reaches its destination.

Basically, the effect arises as a pulse of heat pushes electrons through the bundle of carbon nanotubes, carrying the electrons with it like a bunch of surfers riding a wave.

The improvements in efficiency, Strano says, "brings [the technology] from a laboratory curiosity to being within striking distance of other portable energy technologies," such as lithium-ion batteries or fuel cells. 

In their latest version, the device is more than one percent efficient in converting heat energy to electrical energy, the team reports, which is "orders of magnitude more efficient than what's been reported before." 

In fact, the energy efficiency is about 10,000 times greater than that reported in the original discovery paper.

“It took lithium-ion technology 25 years to get where they are” in terms of efficiency, Strano pointed out, whereas this technology has had only about a fifth of that development time. ​

London, March 15 (IANS) Researchers have presented a new model for what dark matter might be, a discovery that can lead scientists to invisible dark matter that is all around us yet no one has ever seen it and no one knows what it really is.

Physical calculations state that approximately 27 percent of the universe is dark matter. Only five percent is the matter of which all known materials consist: from the smallest ant to the largest galaxy.

For decades, researchers have tried to detect this invisible dark matter.

“Maybe it's because we have looked after dark particles in a way that will never be able to reveal them. Maybe dark matter is of a different character and needs to be looked for in a different way,” explained Martin Sloth, associate professor at University of Southern Denmark.

For decades, physicists have been working on the theory that dark matter is light and therefore interacts weakly with ordinary matter.

This means that the particles are capable of being produced in colliders.

This theory's dark particles are called weakly-interacting massive particles (WIMPs), and they are theorised to have been created in an inconceivably large number shortly after the birth of the universe 13.7 billion years ago.

“But since no experiments have ever seen even a trace of a WIMP, it could be that we should look for a heavier dark particle that interacts only by gravity and thus would be impossible to detect directly,” said Sloth.

Sloth and his colleagues call their version of such a heavy particle a PIDM (Planckian Interacting Dark Matter) particle.

Together with postdoc McCullen Sandora from CP3-Origins and postdoc Mathias Garny from CERN, Sloth now presents a new model for what dark matter might be in a paper published in the journal Physical Review Letters.
In their new model, they calculated how the required number of PIDM particles could have been created in the early universe.

“It was possible, if it was extremely hot. To be more precise the temperatures in the early universe must have been the highest possible in the Big Bang theory,” added Sloth.

“If the universe indeed was as hot as calculated in our model, several gravitational waves from the very early childhood of the universe would have been created. We might be able to find out in the near future,” he pointed out.

With this, Sloth refers to a number of planned experiments around the world that will be able to detect signals from very early gravitational waves.

“If these experiments do not detect such signals, then our model will be falsified. Thus gravitational waves can be used to test our model,” he added.

More than 10 different experiments are planned.

The team aims to measure the polarisation of the cosmic background radiation, either from the ground or with instruments sent up in a balloon or satellite to avoid atmospheric disturbances.​

​London, March 14 (IANS) Using the full power of the Very Large Telescope Interferometer (VLTI) at ESO's Paranal Observatory in Chile, a team of astronomers has recorded sharpest view ever of dusty disc around an ageing star, suggesting that discs around ageing stars are similar to those around young ones.

As they approach the ends of their lives, many stars develop stable discs of gas and dust around them. 

These discs resemble those that form planets around young stars. Till date, astronomers have not been able to compare the two types, formed at the beginning and the end of the stellar life cycle.

Michel Hillen and Hans Van Winckel from the Instituut voor Sterrenkunde in Leuven, Belgium targeted an old double star lying about 4000 light-years from Earth in the southern constellation of Vela (constellation) 

This double star consists of a red giant star, which expelled the material in the surrounding dusty disc, and a less-evolved more normal star orbiting close to it.

“By combining light from several telescopes of the Very Large Telescope Interferometer, we obtained an image of stunning sharpness. The resolution is so high that, for comparison, we could determine the size and shape of a one euro coin seen from a distance of 2,000 km,” said Jacques Kluska, team member from Exeter University in Britain.

The inner edge of the dust ring, seen for the first time in these observations, corresponds very well with the expected start of the dusty disc.

The team found that discs around old stars are very similar to the planet-forming ones around young stars. 

Whether a second crop of planets can really form around these old stars is yet to be determined but it is an intriguing possibility.

“The observations open a new window to study the physics of these discs as well as stellar evolution in double stars,” Winckel said. ​

New York, March 13 (IANS) An enhanced diet is likely to help curb hearing loss due to genetic abnormality that is most commonly responsible for childhood deafness, new research suggests.

A study found that an antioxidant regimen of beta carotene (precursor to vitamin A), vitamins C and E and magnesium helped slow progression of hereditary deafness in mice, with a deletion in Connexin 26 gene -- a protein found on the gene and the most common cause of innate hearing loss.

Connexin 26 alterations are responsible for at least 20 percent of all genetic hearing loss and 10 percent of all childhood hearing loss.

"Our findings suggest that a particular high dose of mineral and vitamin supplements may be beneficial to one genetic mutation," said one of the authors Yehoash Raphael, professor at the Michigan University.

But, the enhanced diet had the opposite effect on another altered mouse modelling with auditory neuropathy -- a rare type of hearing loss.

The negative outcome in this mouse model suggested that different mutations might respond to the special diet in different ways, the researchers noted.

Mice in the study, published in the journal Scientific Reports, received the antioxidant regimen post-natally and in the womb in separate experiments.

In the Connexin 26 mouse model, the enhanced diet was associated with a slower progression of hearing loss and small but significant improvement in hearing thresholds.

However, the mice with auditory neuropathy experienced the opposite outcome, showing accelerated progression of deafness following the diet.

The research follows a case study University of Michigan published in 2015 in which the same nutritional supplements were associated with slowing the progression of deafness for a boy with a Connexin 26 mutation.

Antioxidants have been shown to reduce the impact of oxidative stress in neuronal disorders, cancer, heart diseases and inflammatory diseases.​

New York, March 17 (IANS) In the early stages of Alzheimer's disease, patients are often unable to remember recent experiences. However, a significant research suggests that those memories are still stored in the brain and can be retrieved with a new technique in the near future.

According to neuroscientists including an Indian-origin scientist from the Massachusetts Institute of Technology (MIT), mice in the early stages of Alzheimer's can form new memories just as well as normal mice but cannot recall them a few days later.Furthermore, the researchers were able to artificially stimulate those memories using a technique known as optogenetics, suggesting that those memories can still be retrieved with a little help. Although optogenetics cannot currently be used in humans, the findings raise the possibility of developing future treatments that might reverse some of the memory loss seen in early stage Alzheimer's.

“The important point is that this is a proof of concept. That is, even if a memory seems to be gone, it is still there. It's a matter of how to retrieve it,” said Susumu Tonegawa, director of the RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory.Tonegawa is the senior author of the study which appeared in the journal Nature, and Dheeraj Roy, an MIT graduate student, is the paper's lead author.

The researchers have also shown that they can manipulate these memory traces or engrams to plant false memories, activate existing memories, or alter a memory's emotional associations.To investigate this further, the researchers studied two different strains of mice genetically engineered to develop Alzheimer's symptoms along with a group of healthy mice.All of these mice, when exposed to a chamber where they received a foot shock, showed fear when placed in the same chamber an hour later. However, when placed in the chamber again several days later, only the normal mice still showed fear. 

The Alzheimer's mice did not appear to remember the foot shock.

"Short-term memory seems to be normal, on the order of hours. But for long-term memory, these early Alzheimer's mice seem to be impaired," Roy said.

The researchers then showed that while the mice cannot recall their experiences when prompted by natural cues, those memories are still there.
“Directly activating the cells that we believe are holding the memory gets them to retrieve it," Roy noted, adding that “this suggests that it is indeed an access problem to the information, not that they're unable to learn or store this memory”.
“If we want to recall a memory, the memory-holding cells have to be reactivated by the correct cue. If the spine density does not go up during learning process, then later, if you give a natural recall cue, it may not be able to reach the nucleus of the engram cells," Tonegawa explained.
The researchers were also able to induce a longer-term reactivation of the "lost" memories by stimulating new connections between the entorhinal cortex region of the brain and the hippocampus.

“It's possible that in the future some technology will be developed to activate or inactivate cells deep inside the brain, like the hippocampus or entorhinal cortex, with more precision," Tonegawa added.​

London, March 15 (IANS) Traditionally viewed as a predator of insects, a new study has revealed that spiders like to spice up their menu occasionally with a vegetarian meal.The study showed evidence of spiders from ten families feeding on a wide variety of different plant types such as trees, shrubs, weeds, grasses, ferns or orchids. Also, these spiders demonstrated a diverse taste when it comes to the type of plant food: Nectar, plant sap, honeydew, leaf tissue, pollen and seeds are all on the menu.
As plant-dwelling, highly mobile foragers with excellent capability to detect suitable plant food, these spiders seems to be predestined to include some plant food in their diets.
Spiders diversifying their diet with plants are advantageous as it provides them with additional nutritional supplements and helps them survive when the insects are scarce, said the study detailed in the Journal of Arachnology.
"The ability of spiders to derive nutrients from plants is broadening the food base of these animals; this might be a survival mechanism helping spiders to stay alive during periods when insects are scarce," said study lead author Martin Nyffeler from University of Basel in Switzerland. However, the extent to which the different categories of plant food contribute to the spiders' diet is still largely unexplored.Although spiders feeding on plants are global in its extent, it is reported more frequently from warmer areas, the study said.The researchers suggested that it might be due to the fact that a larger number of the reports relate to nectar consumption, which has its core distribution in warmer areas where plants secreting large amounts of nectar are widespread.​