Knowledge Update

Washington, Sep 16 (IANS) NASA's Cassini spacecraft has entered the final year of its epic voyage during which it will make the the closest-ever observations of Saturn and its rings.

The conclusion of the historic scientific odyssey is planned for September 2017, but not before the spacecraft completes a daring two-part endgame, NASA said in a statement on Friday.

Beginning on November 30, Cassini's orbit will send the spacecraft just past the outer edge of the main rings. 

These orbits, a series of 20, are called the F-ring orbits. During these weekly orbits, Cassini will approach to within 7,800 kms of the centre of the narrow F ring, with its peculiar kinked and braided structure.

"During the F-ring orbits we expect to see the rings, along with the small moons and other structures embedded in them, as never before," said Linda Spilker, Cassini Project Scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. 

"The last time we got this close to the rings was during arrival at Saturn in 2004, and we saw only their backlit side. Now we have dozens of opportunities to examine their structure at extremely high resolution on both sides," Spilker noted.

Cassini's final phase -- called the Grand Finale -- begins in earnest in April 2017, the US space agency said.

A close flyby of Saturn's giant moon Titan will reshape the spacecraft's orbit so that it passes through the gap between Saturn and the rings - an unexplored space only about 2,400 kms wide. 

The spacecraft is expected to make 22 plunges through this gap, beginning with its first dive on April 27.

During the Grand Finale, Cassini will make the closest-ever observations of Saturn, mapping the planet's magnetic and gravity fields with exquisite precision and returning ultra-close views of the atmosphere. 

Scientists also hope to gain new insights into Saturn's interior structure, the precise length of a Saturn day, and the total mass of the rings -- which may finally help settle the question of their age. 

The spacecraft will also directly analyse dust-sized particles in the main rings and sample the outer reaches of Saturn's atmosphere -- both first-time measurements for the mission.

"It's like getting a whole new mission," Spilker said. 

"The scientific value of the F ring and Grand Finale orbits is so compelling that you could imagine a whole mission to Saturn designed around what we're about to do," Spilker noted.

A joint endeavor of NASA, the European Space Agency (ESA) and the Italian space agency, Agenzia Spaziale Italiana (ASI), Cassini is a sophisticated robotic spacecraft orbiting the ringed planet and studying the Saturnian system in detail. 

The mission has already spent more than 12 years studying Saturn, its rings and moons.

​London, Sep 15 (IANS) Old age may slow down memory and other physical and cognitive skills, but the brain has the remarkable potential to reduce these effects, a study has found.

In order to process the information that we receive every day, our brain builds categories into which we sort everything that makes up the world around us.

The study found that this process of categorisation changes as we age. The brains of elderly struggle to categorise and rapidly switch focus from one to another.

"Older people find it harder to switch from one strategy to the other," said Sabrina Schenk, neuroscientist at Ruhr-Universitat Bochum (RUB) in Germany.

But, their brains compensate by paying more attention to detail than younger adults, the study said.

While the young adults spread their attention wide and gather information from different sources, the elderly focus their attention, looking more at detail, the researchers explained.

"To a certain extent, the brain is able to slow down negative effects of ageing by increasing its level of attentiveness," Schenk added.

In the study, the participants were asked to sort circles with varying colour combinations into one of two categories. 

Some of the circles were very similar to each other; others were distinctly different. To which category the circles belonged was indicated by a feedback during the test.

The researchers not only documented the participants' answers, they also recorded their brain waves via an electroencephalogram (EEG) and used an eye tracker to trace their line of vision. 

The results showed that both young and older participants had no difficulties categorising the similar looking circles -- the learning mechanism of both groups were comparable. 

It was only in the later stages of the experiment, when distinct looking circles where shown, that differences between the groups became apparent. 

Older participants found it more difficult to categorise these exceptions than their younger counterparts.

The measurements of brain waves also showed that the elderly develop a particular selective attentiveness.

In other words, they pay more attention to details and look more closely than younger people. This was also confirmed by the eye tracker, the researchers concluded in the paper published in the journal Neuropsychologia.

​Ontario, Sep 15 (IANS) Earth and other planetary objects formed in the early years of the Solar System share similar chemical origins, suggests a new finding.

Neodymium-142 (142Nd) is one of seven isotopes found in the chemical element neodymium which is widely distributed in the Earth's crust and most commonly used for magnets in commercial products like microphones and in-ear headphones.

In 2005, a small variation in 142Nd was detected between chondrites, which are stony meteorites, considered essential building blocks of the Earth and terrestrial rocks. 

These results were widely interpreted as an early differentiation of the interior of the Earth (including the crust and mantle) and these chondrites within the first 30 million years of its history.

The new results published by the journal Nature from Bouvier and Boyet showed that these differences in 142Nd were in fact already present during the growth of Earth and not introduced later, as was previously believed.

"How the Earth was formed and what type of planetary materials were part of that formation are issues that have puzzled generations of scientists. And these new isotopic measurements of meteorites provide exciting answers to these questions about our origins and what made the Earth so special," said Audrey Bouvier, Cosmochemist at the Western University. 

By using vastly improved measurement techniques, Bouvier and his colleague deduced that different meteoritical objects found in the Solar System incorporated the elements neodymium (Nd) and samarium (Sm) but with slightly different isotopic compositions. 

These variations in stable isotopes also show that the Solar System was not uniform during its earliest times and materials formed from previous generations of stars were incorporated in various proportions into the building blocks of planets.

Tokyo, Sep 15 (IANS) Astronomers have found signs of a giant icy planet growing around TW Hydrae, one of the closest young stars to Earth.

Based on the distance from the central star and the distribution of tiny dust grains, the baby planet is thought to be an icy giant, similar to Uranus and Neptune in our solar system. 

"Combined with the orbit size and the brightness of TW Hydrae, the planet would be an giant icy planet like Neptune," said lead researcher Takashi Tsukagoshi at Ibaraki University, Japan.

This result, to be published in the journal Astrophysical Journal Letters, is another step towards understanding the origins of various types of planets.

TW Hydrae is one of the most favourable targets for investigating planet formation.

Past observations have shown that TW Hydrae is surrounded by a disk made of tiny dust particles. This disk is the site of planet formation. 

Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations revealed multiple gaps in the disk. Some theoretical studies suggest that the gaps are evidence of planet formation.

The team observed the disk around TW Hydrae with ALMA in two radio frequencies. Since the ratio of the radio intensities in different frequencies depends on the size of the dust grains, researchers can estimate the size of dust grains. 

The ratio indicates that smaller, micrometer-sized, dust particles dominate and larger dust particles are absent in the most prominent gap with a radius of 22 astronomical units.

Theoretical studies have predicted that a gap in the disk is created by a massive planet, and that gravitational interaction and friction between gas and dust particles push the larger dust out from the gap, while the smaller particles remain in the gap. 

The current observation results match these theoretical predictions.

Researchers believe that the planet is probably a little more massive than Neptune.

​New York, Sep 13 (IANS) Playing music during biopsy for breast cancer diagnosis and treatment helps patients to reduce pre-operative anxiety, a research has found.

The study published in the journal AORN provided insights into the impact of implementing a music therapy programme for surgical patients.

The paper is based on the effect of live and recorded music on the anxiety of 207 women undergoing a biopsy for breast cancer diagnosis and treatment and randomised patients into a control group (no music), a live music group, or a recorded music group. 

The researchers presented patients in the experimental groups with a live song performed by a music therapist at bedside or a recorded song played on an iPod through earphones.

Participants in both live and recorded-music groups experienced a significant reduction in pre-operative anxiety of 42.5 per cent and 41.2 per cent, respectively, when compared to the control group.

"During our two-year trial, we gained information on potential benefits, challenges and methods of facilitating a surgical music therapy program," said Jaclyn Bradley Palmer, Music Therapist at the University Hospitals Seidman Cancer Center, US.

The researcher said that a music therapist may be highly beneficial in the surgical setting, and music therapy may be a means of enhancing the quality of patient care in collaboration with perioperative nurses.

"As an interdisciplinary surgical staff member, the music therapist may help nurses achieve patient-related goals of anxiety reduction, pain management, effective education and satisfaction. And by having professional music therapists facilitate surgical music therapy programs, nursing workloads also may be reduced," Palmer added.

New York, Sep 13 (IANS) Researchers have developed a new technology that can help read brain signals directly and may also aid people with movement disabilities to better communicate their thoughts and emotions.

The technology involves a multi-electrode array implanted in the brain to directly read signals from a region that ordinarily directs hand and arm movements used, for example, to move a computer mouse.

The algorithms translate those signals and help to make letter selections. 

"Our results demonstrate that this interface may have great promise for use in people as it enables a typing rate sufficient for a meaningful conversation," said Paul Nuyujukian, postdoctoral student at Stanford University in California, US.

In an experiment conducted with monkeys, the animals were able to transcribe passages from the national daily New York Times, and Hamlet, a tragedy drama written by William Shakespeare, at a rate of up to 12 words per minute.

Using these high-performing algorithms, the animals could type more than three times faster than with earlier approaches.

However, people using this system would likely type more slowly, the researchers said, while they think about what they want to communicate or how to spell words. 

People might also be in more distracting environments and in some cases could have additional impairments that slow the ultimate communication rate.

Despite that, even a rate lower than the 12 words per minute achieved by monkeys would be a significant advance for people who are not otherwise able to communicate effectively or reliably, Nuyujukian said.

Earlier versions of the technology have already been tested successfully in people with paralysis, but the typing was slow and imprecise. 

The latest work tests improvements to the speed and accuracy of the technology that interprets brain signals and drives the cursor, the researchers said.

"The interface we tested is exactly what a human would use. What we had never quantified before was the typing rate that could be achieved," Nuyujukian added. 

Other technologies for helping people with movement disorders involve tracking eye movements or tracking movements of individual muscles in the face. 

However, these have limitations, and can require a degree of muscle control that might be difficult for some people. 

While some approaches may not enable use of eye-tracking software due to drooping eyelids and others may be too tiring in some people.

Directly reading brain signals could overcome some of these challenges and provide a way for people to better communicate their thoughts and emotions, the researchers noted, in the paper published in the journal Proceedings of the IEEE.

​New York, Sep 13 (IANS) Researchers have developed a new design for harvesting body heat and effectively converting it into electricity for use in wearable electronics.

The experimental prototypes are lightweight, conform to the shape of the body, and can generate far more electricity than previous lightweight heat harvesting technologies, the researchers said.

"Wearable thermoelectric generators (TEGs) generate electricity by making use of the temperature differential between your body and the ambient air," said corresponding author Daryoosh Vashaee, Associate Professor at North Carolina State University.

"Previous approaches either made use of heat sinks -- which are heavy, stiff and bulky -- or were able to generate only one microwatt or less of power per centimetre squared. Our technology generates up to 20 microwatt per cm2 and does not use a heat sink, making it lighter and much more comfortable," he added in a university statement.

The new design begins with a layer of thermally conductive material that rests on the skin and spreads out the heat. 

The conductive material is topped with a polymer layer that prevents the heat from dissipating through to the outside air. 

This forces the body heat to pass through a centrally-located thermoelectric generator. Heat that is not converted into electricity passes through thermoelectric generator into an outer layer of thermally conductive material, which rapidly dissipates the heat. 

The entire system is thin -- only two millimetres -- and flexible.

"In this prototype, the thermoelectric generator is only one centimetre squared, but we can easily make it larger, depending on a device's power needs," Vashaee said.

The researchers also found that the upper arm was the optimal location for heat harvesting.

While the skin temperature is higher around the wrist, the irregular contour of the wrist limited the surface area of contact between the thermoelectric generator band and the skin. 

Meanwhile, wearing the band on the chest limited air flow -- limiting heat dissipation -- since the chest is normally covered by a shirt.

​New York, Sep 14 (IANS) Scientists have in an analysis of nearly two-thirds of the world's languages found that humans tend to use the same sounds for common objects and ideas, no matter what language they speak.

The research, shattered the cornerstone concept in linguistics and demonstrated a robust statistical relationship between certain basic concepts -- from body parts to familial relationships and aspects of the natural world -- and the sounds humans around the world use to describe them, researchers said.

"These sound symbolic patterns show up again and again across the world, independent of the geographical dispersal of humans and independent of language lineage," said Professor and Cognitive scientist Morten H. Christiansen, of Cornell University in New York, US.

"There does seem to be something about the human condition that leads to these patterns. We do not know what it is, but we know it's there," Christiansen added.

For example, in most languages, the word for 'nose' is likely to include the sounds 'neh' or the 'oo' sound, as in 'ooze'; for 'tongue' an 'l' (as in "langue" in French). 

Similarly 'leaf' would include the sounds 'b', 'p' or 'l'; 'sand' uses the sound 's', also words for 'red' and 'round' would include the 'r' sound. 

"It doesn't mean all words have these sounds, but the relationship is much stronger than we'd expect by chance," Christiansen said.

The associations were particularly strong for words that described body parts. 

The team also found certain words are likely to avoid certain sounds. This was especially true for pronouns.



For example, words for 'I' are unlikely to include sounds involving u, p, b, t, s, r and l. 'You' is unlikely to include sounds involving u, o, p, t, d, q, s, r and l, the researchers observed.

For the study, an international team of physicists, linguists and computer scientists from Argentina, Germany, the Netherlands and Switzerland analysed 40-100 basic vocabulary words in 62 per cent of the world's more than 6,000 current languages and 85 per cent of its linguistic lineages.

The words included pronouns, body parts and properties (small, full), verbs that describe motion and nouns that describe natural phenomena (star, fish).

They found a considerable proportion of the 100 basic vocabulary words have a strong association with specific kinds of human speech sounds. 

"The results of the study are conservative; the actual number of sound symbolism patterns may in fact be even greater," Christiansen said.

The findings challenge one of the most basic concepts in linguistics: the century-old idea that the relationship between a sound of a word and its meaning is arbitrary.

The researchers do not know why humans tend to use the same sounds across languages to describe basic objects and ideas.



But these concepts are important in all languages, and children are likely to learn these words early in life, Christiansen noted in the paper published in the journal Proceedings of the National Academy of Sciences.

​New York, Sep 14 (IANS) Researchers should not rely on the clinical symptoms of memory loss alone to diagnose Alzheimer's disease because there could be other indicants of the neurodegenerative disease that do not initially affect memory, says a new study.

There are more than just one symptom of Alzheimer's disease. These could be language problems, disruptive individual behaviour and personality disorder -- even judgement of someone's concept of the position of objects in space, said researchers at Northwestern University, in Evanston, of Illinois, in the US.

If it affects personality, it may cause lack of inhibition. For example, someone who was shy might one day go up to the grocery store clerk -- who is a complete stranger -- and try to hug or even kiss her. 

This all depends on what part of the brain is affected by Alzheimer's, the study said.

However, "these individuals are often overlooked in clinical trial designs and thus miss out on opportunities to participate in the experiments formulated to treat Alzheimer's", said lead author and Associate Professor Emily Rogalski at Northwestern University.

"Such individuals are often excluded because they don't show memory deficits, inspite of sharing the same disease (Alzheimer's) that's causing their symptoms," Rogalski added.

In the study, the authors identified the clinical features of individuals with primary progressive aphasia (PPA) -- a rare dementia that causes progressive declines in language abilities due to Alzheimer's disease. 

During the initial phase of PPA, memory and other thinking abilities are relatively intact. Also, PPA can be caused either by Alzheimer's disease or another neurodegenerative disease family called Frontotemporal lobar degeneration (FTLD). 

The study demonstrated that knowing an individual's clinical symptoms was not enough to determine whether PPA was due to Alzheimer's or any other neurodegenerative disease -- where progressive loss of structure or function of neurons, including death of neurons happen. 

Therefore, an amyloid positron emission tomography (PET) scan -- an imaging test -- should be taken.

PET scan tracks the presence of amyloid -- an abnormal protein whose accumulation in the brain is a hallmark of Alzheimer's. 

PET scan should be used in early life to determine the likelihood of Alzheimer's disease pathology in later life, the researchers said in the study published online in the journal Neurology. 

London, Sep 14 (IANS) On its way to assembling the most detailed 3D map ever made of our Milky Way galaxy, European Space Agency's Gaia probe has pinned down the precise position in the sky and the brightness of 1,142 million stars, astronomers working on the mission have said.

The first catalogue of more than a billion stars from Gaia satellite was published on Wednesday -- the largest all-sky survey of celestial objects to date.

The release also features the distances and the motions across the sky for more than two million stars.

"Gaia is at the forefront of astrometry, charting the sky at precisions that have never been achieved before," said Alvaro Gimenez, ESA's Director of Science.

"Today's release gives us a first impression of the extraordinary data that await us and that will revolutionise our understanding of how stars are distributed and move across our Galaxy," Gimenez said in a statement on Wednesday.

Launched in 2013 on a Soyuz-STB/Fregat-MT launch vehicle from the European Spaceport in Kourou, French Guiana, Gaia started its scientific work in July 2014. 

This latest release is based on data collected during its first 14 months of scanning the sky, up to September 2015.

"The beautiful map we are publishing today shows the density of stars measured by Gaia across the entire sky, and confirms that it collected superb data during its first year of operations," Timo Prusti, Gaia project scientist at ESA, said.

Gaia probe was launched with the aim of making the largest, most precise three-dimensional map of our galaxy by surveying more than a thousand million stars.

At its heart, Gaia contains two optical telescopes that work with three science instruments to precisely determine the location of stars and their velocities, and to split their light into a spectrum for analysis.

During its planned five-year mission, the spacecraft spins slowly, sweeping the two telescopes across the entire celestial sphere. 

As the detectors repeatedly measure the position of each celestial object, they will detect any changes in the object's motion through space.