Knowledge Update

​London, April 5 (IANS) The North Atlantic Ocean played a key role in the last climate transition, says a study providing valuable insights into why large continental ice-sheets first grew in North America and Scandinavia some 2.7 million years ago.

An international team of researchers measured the composition of isotopes of the chemical element neodymium that can be found in fish teeth preserved in a North Atlantic marine core to track the origin of deep waters bathing the bottom of the ocean during the climate transition that took place in the late Pliocene Epoch era.

Contrary to previous assertions, they found that the first of these glacial events in the northern hemisphere was associated with major expansions of carbon-rich southern-sourced deep waters into the northwestern Atlantic abyss, over one million years earlier than previously thought.

The study, published recently in the journal Nature Geoscience, said that three of the largest glacial cycles between 2.5 and 2.7 million years ago appear to be associated with southern-sourced water incursions into the deep Atlantic that were as significant as those documented for the last glacial maximum.

"We could not have made these new findings with confidence using only a classic method for tracing watermass origin such as carbon isotopes," said Ian Bailey from the University of Exeter in Britain.

"But when we combined such data with an alternative novel proxy such as neodymium isotopes, we were able to reveal a dramatically new picture of watermass mixing in the deep North Atlantic during late Pliocene glacial intensification," Bailey added.

It has long been argued that changes in North Atlantic circulation played a leading role in driving late Pliocene northern hemisphere glaciation because of its capacity to modulate the transfer of heat and moisture from the tropics to the poles.

"Our findings suggest, though, that the North Atlantic Ocean was not a driving factor in this transition, but, through storage of atmospheric carbon dioxide in the deep Atlantic, it operated as a positive feedback that helped to usher in glaciation at this time," Bailey said.

"What we've done is document a process which is thought to be special to the largest and longest glacial cycles of the past one million years, but we have shown that it has been occurring ever since large continental ice-sheets formed in the Northern Hemisphere," he added.​

​New York, April 5 (IANS) Some landslides travel much greater distances than scientists would normally expect. Now a team of researchers has come out with an explanation for this phenomenon using a sophisticated computer model.

A team of geoscientists from Brown University, Purdue University and the University of Southern California in the US has found that vibrations generated by large slides can cause tonnes of rock to flow like a fluid, enabling the rocks to rumble across vast distances.

According to the study's lead author Brandon Johnson, an assistant professor at Brown, the "runout" distance of most landslides -- the distance debris travels once it reaches flat land -- tends to be about twice the vertical distance that the slide falls. 

So if a slide breaks loose a half-mile vertically up a slope, it can be expected to run out about a mile.

But "long-runout" landslides, also known as sturzstroms, are known to travel horizontal distances 10-20 times further than they fall. 

"There are a few examples where these slides have devastated towns, even when they were located at seemingly safe distances from a mountainside," Johnson said. 

Scientists developed several hypotheses to explain long-runout slides. But none could convincingly explain their behaviour. 

In 1995, Charles Campbell from the University of Southern California created a computer model that was able to replicate the behaviour of long-runout slides using only the dynamic interactions between rocks.

However, due to the limitations of computers at the time, he was unable to determine what mechanism was responsible for the behaviour.

"The model showed that there was something about rocks, when you get a lot of them together, that causes them to slide out further than you expect," Johnson said. "But it didn't tell us what was actually happening to give us this lower friction."

For this new study, described in the Journal of Geophysical Research: Earth Surface, Johnson was able to resurrect that model, tweak it a bit, and run it on a modern workstation to capture the dynamics in finer detail. 

The new model showed that, indeed, vibrations do reduce the effective friction acting on the slide.

The amount of friction acting on a slide depends in part on gravity pulling it downward. 

The same gravitational force that accelerates the slide as it moves downslope tends to slow it down when it reaches flat land. But the model showed that vibrational waves counteract the gravitational force for brief moments. 

The rocks tend to slide more when the vibration reduces the friction effect of the gravitational force. Because the vibrational waves affect different rocks in the slide at different times, the entire slide tends to move more like a fluid.​

​New York, April 5 (IANS) Researchers have identified a pattern of brain activity that may be a sign of memory problems in people with schizophrenia.

The findings proved that memory problem in schizophrenia stems from disruptions in the brain's dorsolateral prefrontal cortex (DLPFC), long hypothesised by scientists. 

This area of the brain plays a key role in working memory -- the system for temporarily storing and managing information required to carry out complex cognitive tasks. 

"Our findings provide evidence that the DLPFC is compromised in patients with schizophrenia," said first author Jared X. Van Snellenberg, assistant professor at Columbia University in US. 

In the study, published in the journal Biological Psychiatry, 45 healthy controls and 51 schizophrenia patients, including 21 who were not taking antipsychotic medications, were given the eight-level memory test while undergoing fMRI imaging. 

The healthy controls demonstrated a gradual increase in DLPFC activation, followed by a gradual decrease in activation, as the task got harder. 

But in both medicated and unmedicated schizophrenia patients, the overall response was significantly weaker, with the weakest response occurring in those who had the most difficulty with the memory task.

While schizophrenia typically causes hallucinations and delusions, many people with the disorder also have cognitive deficits, including problems with short- and long-term memory, which is one of the most devastating symptoms.

"Of all the symptoms linked to schizophrenia, memory issues may have the greatest impact on quality of life, as they can make it difficult to hold down a job and maintain social relationships," Van Snellenberg stated.​

​New York, April 5 (IANS) Anti-oxidants are likely to be an effective method of treatment for elderly patients suffering from melanoma, finds a new study.

It also identified that the older tumour cells in the worst form of skin cancer behave differently than the younger tumour cells.

The research showed that changes in the microenvironment make these older tumours cells to spread more and makes them more resistant to treatment with targeted therapies.

"It's fascinating to see that the microenvironment can have such a profound effect on both metastasis, and response to a therapy that is specifically targeted to a mutation in a gene," said lead author Ashani Weeraratna, associate professor at The Wistar Institute in US.

However, the findings revealed that antioxidant N-acetylcysteine (NAC) killed melanoma cells in aged dermal fibroblasts - the cells found in the skin.

Cells found in the skin help the skin recovery from injuries, and can contribute to the growth and invasion of melanoma cells. 

For the study, published in the journal Nature, the researchers used dermal fibroblasts from healthy donors 25-35 years of age or from donors 55-65 years of age.

They determined that a secreted factor sFRP2 was present in aging cells, which regulates beta-catenin -- a protein that normally blocks the invasion of melanoma cells. 

The age-induced loss of beta-catenin renders melanoma cells less capable of dealing with reactive oxygen species (ROS), resulting in a genetically unstable tumour.

The increased activity of ROS and decreased levels of beta-catenin all contribute to the increased resistance of melanoma to treatment with drugs that inhibit a gene, BRAF, mutated in approximately half of all cases of the skin cancer. 

"Our findings highlight how vital it is to treat that melanoma in an age-appropriate manner," said one of the researchers Amanpreet Kaur, a graduate student at The Wistar Institute. 

​New York, April 5 (IANS) Electrical stimulation of a deep, middle brain structure blocks pain signals at the spinal cord level without drug intervention, finds a new study.

"This is the first study to use a wireless electrical device to alleviate pain by directly stimulating the ventral tegmental area of the brain," said Yuan Bo Peng, a psychology professor at the University of Texas in Arlington.

"While still under laboratory testing, this new method does provide hope that in the future we will be able to alleviate chronic pain without the side effects of medications," Peng added.

Peng and J.C. Chiao, an electrical engineering professor, detail their discoveries in the neuroscience journal Experimental Brain Research.

In their experiments, the researchers used their patented custom-designed wireless device to demonstrate that stimulation of the ventral tegmental area reduced the sensation of pain. They also confirmed that this stimulation reduced pain signals in the spinal cord, effectively blocking the perception of pain.

The process also triggered the release of beneficial dopamine, which may reduce the emotional distress associated with long-term pain, researchers said.

"Until this study, the ventral segmental area of the brain was studied more for its key role in positive reinforcement, reward and drug abuse," Peng said. "We have now confirmed that stimulation of this area of the brain can also be an analgesic tool," he added.​

​New York, April 5 (IANS) Scientists have proposed a new concept that could make it possible to generate electricity from coal with much greater efficiency -- possibly reaching as much as twice the fuel-to-electricity efficiency of today's conventional coal plants.

The concept, proposed by doctoral student Katherine Ong and professor Ahmed Ghoniem at the Massachusetts Institute of Technology (MIT), combines into a single system two well-known technologies -- coal gasification and fuel cells.

Coal gasification is a way of extracting burnable gaseous fuel from pulverised coal, rather than burning the coal itself, while fuel cells produce electricity from a gaseous fuel by passing it through a battery-like system where the fuel reacts electrochemically with oxygen from the air.

The attraction of combining these two systems, explained in the Journal of Power Sources, is that both processes operate at similarly high temperatures of 800 degrees Celsius or more. 

Combining them in a single plant would thus allow the two components to exchange heat with minimal energy losses. In fact, the fuel cell would generate enough heat to sustain the gasification part of the process, Ong said, eliminating the need for a separate heating system, which is usually provided by burning a portion of the coal.

Coal gasification, by itself, works at a lower temperature than combustion and "is more efficient than burning," Ong said. 

First, the coal is pulverised to a powder, which is then heated in a flow of hot steam, somewhat like popcorn kernels heated in an air-popper. The heat leads to chemical reactions that release gases from the coal particles -- mainly carbon monoxide and hydrogen, both of which can produce electricity in a solid oxide fuel cell.

In the combined system, these gases would then be piped from the gasifier to a separate fuel cell stack, or ultimately, the fuel cell system could be installed in the same chamber as the gasifier so that the hot gas flows straight into the cell. 

In the fuel cell, a membrane separates the carbon monoxide and hydrogen from the oxygen, promoting an electrochemical reaction that generates electricity without burning the fuel.

Because there is no burning involved, the system produces less ash and other air pollutants than would be generated by combustion, the MIT researchers said.

It does produce carbon dioxide, but this is in a pure, uncontaminated stream and not mixed with air as in a conventional coal-burning plant. That would make it much easier to carry out carbon capture and sequestration (CCS) -- that is, capturing the output gas and burying it underground or disposing of it some other way -- to eliminate or drastically reduce the greenhouse gas emissions. 

In conventional plants, nitrogen from the air must be removed from the stream of gas in order to carry out CCS.

One of the big questions answered by this new study, which used simulations rather than lab experiments, was whether the process would work more efficiently using steam or carbon dioxide to react with the particles of coal. 

Both methods have been widely used, but most previous attempts to study gasification in combination with fuel cells chose the carbon dioxide option. This new study demonstrates that the system produces two to three times as much power output when steam is used instead.​

​London, April 5 (IANS) A daily dose of vitamin D3 is likely to improve the functioning of the heart in people with chronic failure of the organ, a new study has found.

The results revealed that for patients with heart disease taking vitamin D3 regularly may lessen the need for them to be fitted with an implantable cardioverter defibrillator (ICD), a device that detects dangerous irregular heart rhythms and can shock the heart to restore a normal rhythm.

The patients, in the study, who took vitamin D3 experienced an improvement in heart functioning, as compared to those who did not.

The ejection fraction -- measuring the pumping of blood from the heart with each heartbeat -- in heart failure patients is often significantly impaired whereas in a healthy person it is usually between 60 and 70 percent.

The heart's pumping function improved from 26 percent to 34 percent, in patients who took Vitamin D3.

"This is a significant breakthrough for patients. It is the first evidence that vitamin D3 can improve heart functioning of people with heart muscle weakness -- known as heart failure," said led researcher Klaus Witte from the University of Leeds in Britain.

The study involved more than 160 patients from Leeds who were already being treated for their heart failure using proven treatments including beta-blockers, ACE-inhibitors and pacemakers.

The targeted patients were asked to take vitamin D3 or a dummy (placebo) tablet for one year. Those who took placebo, there was no change found in cardiac function.

The findings could make a significant difference to the care of heart failure patients as ICDs are expensive and involve an operation, the researchers maintained.

Heart failure affects more than 23 million worldwide.The condition can affect people of all ages, but it is more common in older people -- more than half of all people globally with heart failure are over the age of 75.

The findings were presented at the American College of Cardiology 65th Annual Scientific Session & Expo in Chicago, US.​

New York, April 6 (IANS) Researchers have found that babies raised in bilingual households show brain activity linked to executive functioning as early as when they are 11 months old.

Bilingual children have more activity in areas associated with executive function, a set of mental abilities that includes problem-solving, shifting attention and other desirable cognitive traits, and the difference in their brain activity is evident as early as 11 months of age.

"Our results suggest that before they even start talking, babies raised in bilingual households are getting practice at tasks related to executive function," said lead author Naja Ferjan Ramírez from University of Washington.

"This suggests that bilingualism shapes not only language development, but also cognitive development more generally," Ramírez added in the paper published online in the journal Developmental Science.

Brains of babies from bilingual families are more open to learning new language sounds, compared with babies from monolingual families.

The team used magnetoencephalography (MEG), which measures magnetic changes given off by active nerve cells. 

They compared the brain responses to the language sounds of 16 11-month-old babies -- eight from English-only households and eight from Spanish-English households. 

The Spanish-English bilingual babies had stronger brain responses to speech sounds, compared with English-only babies, the study found.

The findings suggested that the boost bilingualism gives to executive function areas in the brain could arise from switching back and forth between languages, allowing them to routinely practice and improve executive function skills.

"The 11-month-old baby brain is learning whatever language or languages are present in the environment and is equally capable of learning two languages as it is of learning one language," Ferjan Ramírez said.

"Our results underscore the notion that not only very young children capable of learning multiple languages, but that early childhood is the optimum time for them to begin," she said.​

​London, April 6 (IANS) Scientists have discovered a new biochemical process, which reveals how the lungs operate during normal functioning and during asthma -- a chronic respiratory condition marked by difficulty in breathing.

The study conducted in mouse model reveals how air enters and leaves the lungs.

The findings showed that disrupting these biochemical pathways in a mouse model could prevent airway narrowing and maintain normal lung function.

"The fundamental biochemical process that we have discovered will ultimately allow us to better design ways to develop new treatments for those suffering from asthma and chronic obstructive pulmonary disease (COPD)," said one of the researchers Andrew Tobin, professor at the University of Leicester in Britain.

It is too early to say whether these results apply to humans, the researchers maintained in the study published in the journal Proceedings of the National Academy of Sciences.

The lung is made up of tiny tubes called airways, surrounded by muscles that allow air in and out of the lung.

In asthma and other airway diseases such as COPD, the airway muscle contracts causing the airways to become narrow and restricting the flow of air in and out of the lung.

"This breakthrough will lay the essential foundations on which to build new strategies to combat airway diseases such as asthma," added Tobin.

According to the World Health Organisation estimates, 235 million people worldwide currently suffer from asthma with over 80 percent of asthma deaths occurring in low and lower-middle income countries. The disease is predicted to increase worldwide over the next 10 years.​

​New York, April 6 (IANS) Robots having close resemblance with humanoid robot movie characters like C-3PO and Wall-E, which are seen as "friendly, non-threatening computers", can evoke emotional response from humans, a study has found.

In an experiment, researchers at Stanford University used a human-shaped robot which was programmed to verbally instruct study participants to touch 13 parts of its body.

Participants were fitted with an Affectiva Q-Sensor on the fingers of their non-dominant hand. This measured skin conductance, a measure of physiological arousal, and reaction time of the participant.

The findings, which will be presented in June at the 66th Annual Conference of the International Communication Association in Fukuoka, Japan, showed that when participants were instructed to touch the robot in areas that people usually do not touch, like the eyes or the buttocks, they were more emotionally aroused when compared to touching more accessible parts like the hands and neck. 

Participants also were more hesitant to touch these intimate parts based on the response times.

"Our work shows that robots are a new form of media that is particularly powerful. It shows that people respond to robots in a primitive, social way," said Stanford researcher Jamy Li.

"Social conventions regarding touching someone else's private parts apply to a robot's body parts as well. This research has implications for both robot design and theory of artificial systems," Li added.​