Knowledge Update

Melbourne, May 16 (IANS) Using space dust, researchers from Monash University here have made a surprising discovery about the chemistry of Earth's atmosphere 2.7 billion years ago, thus challenging the accepted view that Earth's ancient atmosphere was oxygen-poor.

The ancient Earth's upper atmosphere contained about the same amount of oxygen as today and that a methane haze layer separated this oxygen-rich upper layer from the oxygen-starved lower atmosphere, the team noted.

“Using cutting-edge microscopes, we found that most of the micrometeorites (space dust) had once been particles of metallic iron - common in meteorites - that had been turned into iron oxide minerals in the upper atmosphere, indicating higher concentrations of oxygen than expected," explained Andrew Tomkins from Monash University.

He explained how the team extracted micrometeorites from samples of ancient limestone collected in the Pilbara region in western Australia and examined them at the Monash Centre for Electron Microscopy (MCEM) and the Australian Synchrotron.

“This was an exciting result because it is the first time anyone has found a way to sample the chemistry of the ancient Earth's upper atmosphere,” Tomkins noted in a paper appeared in the journal Nature.

Co-researcher Matthew Genge from Imperial College London performed calculations that showed oxygen concentrations in the upper atmosphere would need to be close to modern day levels to explain the observations.

“This was a surprise because it has been firmly established that the Earth's lower atmosphere was very poor in oxygen 2.7 billion years ago. How the upper atmosphere could contain so much oxygen before the appearance of photosynthetic organisms was a real puzzle," Genge noted.

The results suggest the Earth at this time may have had a layered atmosphere with little vertical mixing, and higher levels of oxygen in the upper atmosphere produced by the breakdown of carbon dioxide by ultraviolet (UV) light.

A possible explanation for this layered atmosphere might have involved a methane haze layer at middle levels of the atmosphere.

The methane in such a layer would absorb UV light, releasing heat and creating a warm zone in the atmosphere that would inhibit vertical mixing.

“By studying fossilised particles of space dust the width of a human hair, we can gain new insights into the chemical makeup of Earth's upper atmosphere, billions of years ago,” Tomkins pointed out.

The next stage for the team will be to extract micrometeorites from a series of rocks covering over a billion years of Earth's history in order to learn more about changes in atmospheric chemistry and structure across geological time.

“We will focus particularly on the great oxidation event, which happened 2.4 billion years ago when there was a sudden jump in oxygen concentration in the lower atmosphere,” the authors noted.

Sydney, May 17 (IANS) A study released on Tuesday has found that a high concentration of coal dust can quickly kill coral on Australia's Great Barrier Reef.

The research by the Australian Institute of Marine Science discovered coal dust could also slow the growth rate of seagrasses and fish, Xinhua news agency reported.

"Corals exposed to the highest concentrations of coal dust died within two weeks," author Kathryn Berry said.

"Corals exposed to lower concentrations of coal lasted longer, but most of them also died after four weeks of exposure."

She noted that while some fish and seagrass died from coal dust exposure, it mostly stunted their growth by half compared to clean water.

The study found coal dust entered the marine environment at loading and storage facilities, or when it is blown into the sea during transport.

Researches also noted a shipping disaster as a possible risk to the reef.

"Risks to the Great Barrier Reef posed by large coal spills depend on the probability of an accident and the potential impacts to marine life," author Andrew Negri said.

"While the likelihood of a major spill on a coral reef or seagrass meadow is low, we are now beginning to understand the likely consequences."

Researchers hope the results will send a message to coal shipping companies in Australia and across the world.​

​New York, May 17 (IANS) The mother's voice can lighten up and engage the child's brain far more than the voices of women they do not know, say researchers including an Indian-origin scientist.

The findings showed that brain regions that respond more strongly to the mother's voice extend beyond regions of hearing.

It included regions of emotion and reward processing, social functions, detection of what is personally relevant and face recognition.

Also, the strength of connections between the brain regions activated by the voice of own mother predicted the child's social communication abilities.

"Many of our social, language and emotional processes are learned by listening to our mom's voice," said lead author Daniel Abrams from Stanford University in the US. 

"But surprisingly little is known about how the brain organises itself around this very important sound source. We didn't realise that a mother's voice would have such quick access to so many different brain systems," Abrams said.

"We wanted to know: Is it just auditory and voice-selective areas that respond differently, or is it more broad in terms of engagement, emotional reactivity and detection of salient stimuli," added Vinod Menon, professor at Stanford University.

For the study, published in the journal Proceedings of the National Academy of Sciences, the team examined 24 children ages 7 to 12. None had any developmental disorders, and were raised by their biological mothers. 

Each child's mother was recorded saying three nonsense words and two other women also were recorded saying the three nonsense words. The children's brains were then scanned using MRIs.

The results revealed that the children could identify their own mother with 97 percent accuracy, even after listening to recordings less than 1 second long.

"The study can be an important new template for investigating social communication deficits in children with disorders such as autism," Menon noted. ​

​Toronto, May 17 (IANS) Researchers have uncovered a new molecular mechanism for stimulating the body to burn fat -- a discovery that could lead to new medications to fight obesity, diabetes and heart diseases.

By knocking out the gene that produces a protein, known as folliculin, in fat cells in mice, the researchers triggered a series of biomolecular signals that switched the cells from storing fat to burning it.

This process is known as the 'browning' of fat cells. The principal role of brown fat is to burn energy to produce heat, which helps keep our body temperature constant. White fat serves as an energy-storage tissue.

Scientists recently discovered a new type of fat tissue with characteristics somewhere between healthy brown fat and the not-so-healthy white kind. The so-called beige fat is capable of behaving like brown fat in response to certain stimuli such as exposure to cold. 

"Conversion from white fat cells to beige or brown fat cells is a very desirable effect in the obesity, diabetes, and metabolic syndrome indications, since excess energy in the body is not stored in fat tissue but is burned in brown or beige fat tissue," said the study's senior author Arnim Pause, professor at McGill University in Montreal, Canada.

For the study, published in the journal Genes & Development, the team bred mice to have fat cells that did not produce folliculin. They then fed normal mice and folliculin-deficient mice with a high-fat, junk food-like diet over 14 weeks. 

Normal mice gained weight rapidly, whereas folliculin-deficient mice remained slim.

By measuring rates of oxygen consumption and CO2 production, the researchers found the folliculin-deficient mice were burning more fat. 

At the end of the trial, these mice had smaller white fat cells and less white fat tissue overall.

The extra energy they were producing made them better at tolerating cold temperatures, too, the researchers said.

The research could open the way for new medications to be developed that will stimulate the 'browning' process.

"One implication (of the study) is that a drug could be developed to stimulate the activity of beige/brown fat cells and thus help manage obesity and other metabolic disorders," Vincent Giguere from the University in Montreal noted.​

​New York, May 17 (IANS) Researchers have discovered a biological mechanism that could lead to a potential way to "tune up" the immune system's ability to kill cancer cells.

In the study, published in the journal Proceedings of the National Academy of Sciences, they reported that a protein called Kruppel-like factor 2 (KFL2) is critical for expansion and survival of natural killer (NK) cells, a type of white blood cell that specifically recognise and destroy tumour cells.

NK cell-mediated tumor therapy -- essentially, injections of NK cells -- is a cutting-edge technique currently used clinically. 

It can sweep the blood clean of cancer cells in leukemia patients. However, the remission is often short-lived.

The protein reported in this study both limits immature NK cell proliferation and helps mature NK cells to be rich in interleukin 15 (IL-15), which is necessary for their continued survival.

"This is the same process likely used by cancer cells to avoid destruction by NK cells," said one of the researchers Eric Sebzda from Vanderbilt University Medical Centre in Tennessee, US.

In particular, tumours may avoid immune clearance by promoting the destruction of the protein within the NK cell population, thereby starving these cells of IL-15.

The researchers believe that the findings could lead to new cancer therapy.​

Bangkok, May 16 (IANS) Thai authorities have decided to close down tourism in Tachai Island in the Andaman Sea, to protect the coral and underwater flora and fauna in one of the country's key diving destinations, an official said on Monday.

"The island is closed for an indefinite time. Too many tourists have visited it. They have destroyed the ecology and corals of the island," Efe news quoted the official as saying.

The island will no longer be accessible to tourists after October 15 and the committee managing Similan National Park will evaluate the situation to determine when the recovery period is over.

The measure, however, excludes two diving centres operating in the area, because deep sea diving has a minimal impact on the environment and tourists are educated not to damage nature, said the official.

The freshwater golden snail and the hermit crab that uses the snail's shell for shelter are just two of the species that have been affected by tourism, according to the official.

"When it reopens, we plan to adopt more stringent measures" to control the volume of tourists, he said.

Although Tachai lacks hotel infrastructure and opened its doors to tourism in 2010, its landscape, beaches and location within the Similan National Park -- about 620 km northwest of Phuket -- have rapidly turned it into a tourist hotspot.

Thailand recorded 29.9 million tourists in 2015 and the numbers are expected to surge up to 35 million in 2016 if tourism continues its current pace, according to data from the Tourism Department.​

New York, May 16 (IANS) Are you keen on shedding those extra kilos, but are unable to maintain consistency? Take heart, as according to a new study, participating in a weight-loss programme for long-term can help manage your body weight.

Losing weight is difficult and at the same time maintaining the new healthy weight, which is associated with lower blood pressure, blood sugar, improved sleep, over years is even harder. 

The results demonstrate that long-term participation in weight-loss programme could be effective in sustaining weight loss and ward off obesity.

"Maintaining long-term weight loss is a critical challenge in treating obesity and other health problems such as diabetes, high blood pressure and heart disease," said lead author Nia Mitchell from University of Colorado in the US.

The team followed over 65,000 overweight or obese people who joined a national programme called 'Take Off Pounds Sensibly' (TOPS), from 2005 to 2010. 

The findings revealed that half of the participants showed significant weight loss in the first year. 

Out of those who participated in the second year, 80 percent kept off the weight.

During years three to seven, nearly 90 percent of participants who continued the programme maintained their weight loss steadily.

Consistent participation in the weight loss programme for one year helped the participants to sustain their new healthy weight, the researchers noted.

"Just losing the weight isn't enough. Since the health benefits of weight loss disappear when weight creeps back on, we need more research into effective strategies for maintaining a healthier weight once it is reached," Mitchell added.

The findings were presented at the recently held Society of General Internal Medicine 2016 Annual Meeting in Florida.​

New York, May 17 (IANS) Regular exercise at any age could keep the mind young and help you stave off Alzheimer's disease and other dementias.

People with dementia may experience memory loss and difficulties with thinking, problem-solving or language.

In this study, the researchers discovered a positive correlation between fitness and blood flow to areas of the brain where the hallmark tangles and plaques of Alzheimer's disease pathology are usually first detected.

"This is an important first step towards demonstrating that being physically active improves blood flow to the brain and confers some protection from dementia," said lead researcher Nathan Johnson from the University of Kentucky College of Health Sciences in the US.

Conversely, the findings suggest that people who live sedentary lifestyles, especially those who are genetically predisposed to Alzheimer's, might be more susceptible.

The findings were published in the journal NeuroImage.

For the study, thirty men and women aged 59-69 were put through treadmill fitness assessments and ultrasounds of the heart. Then they received brain scans to look for blood flow to certain areas of the brain.

"We set out to characterise the relationship between heart function, fitness, and cerebral blood flow, which no other study had explored to date," Johnson said.

"In other words, if you're in good physical shape, does that improve blood flow to critical areas of the brain? And does that improved blood flow provide some form of protection from dementia?," Johnson noted.

The results showed blood flow to critical areas of the brain - and so the supply of oxygen and vital nutrients - was higher in those who were more physically fit.

This study demonstrates that regular exercise at any age could keep the mind young, Johnson said.

Since people who exercise frequently often have reduced arterial stiffness, the researchers believe that regular physical activity -- regardless of age -- maintains the integrity of the "pipes" that carry blood to the brain.​

​Tokyo, May 17 (IANS) Environment ministers from the Group of Seven (G7) nations on Monday in Japan collectively said they were committed to ensuring global climate change would be tackled swiftly in line with a deal struck in Paris last year.

​New Delhi, May 16 (IANS) The World Bank said on Monday it has approved a $625 million loan to support India's grid connected rooftop solar programme to generate clean energy.