Knowledge Update

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.​

​London, March 11 (IANS) It is often assumed that as our income rises so does our life satisfaction but this may not be the case with many people.

According to researchers, what really matters is when income is lost and this is only important for people who are highly conscientious, hard working and diligent.

The research, which examined levels of life satisfaction and income changes in more than 18,000 adults over a nine-year period, revealed that income change is only important when individuals with specific personality characteristics experience an income loss.

According to the team, continually increasing our income is not an important factor for achieving greater happiness and well-being for most people living in economically-developed countries.

"Instead, we should aim for financial stability to achieve greater happiness while protecting those individuals who experience negative income shocks," said Christopher Boyce of the behavioural science centre at the University of Stirling in Britain.

The study, involving two separate samples from Germany and Britain, asked participants annually about their income level and how satisfied they were with life.

Participants also answered questions on their personality at the start of the study.

Results revealed that regardless of personality, income increases did not affect life satisfaction.

When people lost income, however, there was a reduction in their life satisfaction.

This was far greater for those who reported themselves as being conscientious, namely they were thorough in their attitudes to life and work, energetic, effective and efficient in how they did things.

The study accounted for shifting circumstances such as entering or leaving work and changes to health and household make up.

It found that for people that were only even moderately conscientious, a loss of income had a negative impact at least two and a half times greater than less conscientious individuals.​