Knowledge Update

​London, June 20 (IANS) The same asteroid that killed the dinosaurs in the Cretaceous period 66 million years ago also wiped out over 90 per cent of mammal species, significantly more than previously thought, new research has found.

Following the asteroid hit, most of the plants and animals would have died, so the survivors probably fed on insects eating dead plants and animals. 

With so little food, only small species survived. The biggest animals to survive on land would have been no larger than a cat, the study said.

For the study, the researchers reviewed all mammal species known from the end of the Cretaceous period in North America. 

Their results showed that over 93 per cent became extinct across the Cretaceous-Paleogene (K-Pg) boundary, but that they also recovered far more quickly than previously thought.

The scientists analysed the published fossil record from western North America from two million years before the Cretaceous-Paleogene boundary, until 300,000 years after the asteroid hit. 

They compared species diversity before and after this extinction event to estimate the severity of the event and how quickly the mammals recovered. 

"The species that are most vulnerable to extinction are the rare ones, and because they are rare, their fossils are less likely to be found. The species that tend to survive are more common, so we tend to find them,” said one of the researchers Nick Longrich from Milner Centre for Evolution in University of Bath in England.

"The fossil record is biased in favour of the species that survived. As bad as things looked before, including more data shows the extinction was more severe than previously believed," Longrich noted.

The researchers said this explains why the severity of the extinction event was previously underestimated. 

The study was published in the Journal of Evolutionary Biology.

New York, June 19 (IANS) Scientists have built a new software that can quickly and efficiently model and print thousands of hair-like structures -- a task that normally takes a huge amount of computational time and power through conventional software.

Tehran, June 19 (IANS) Iran has reached an agreement with the US Boeing to purchase 100 passenger planes to renew the country's aging fleet, the media reported on Sunday.

The deal awaits the US government's approval, head of Iran's Civil Aviation Organisation (CAO) Ali Abedzadeh said, Xinhua reported.

​Dubai, June 19 (IANS/WAM) The UAE and Germany reviewed means to strengthen economic relations and develop partnerships between the business communities in the two countries.

​New York, June 18 (IANS) Scientists have identified a single gene pathway that can disrupt Zika and similar viruses from spreading in the body and also act as a potential drug target for such deadly diseases.

The findings showed that disabling SPCS1 -- in both human and insect cells -- reduces viral infection and does not negatively affect the cells themselves.

"We wanted to find out if we could identify genes present in the host cells that are absolutely required by the virus for infection," said Michael Diamond, Professor at Washington University.

While the absence of SPCS1 gene shut down the spread of flaviviruses, eliminating the gene had no detrimental effect on other types of viruses, including alphaviruses, bunyaviruses and rhabdoviruses, the researchers said.

"In these viruses, without SPCS1 gene the chain reaction doesn't happen and the virus can't spread. So this gene can act as a potential drug target because it disrupts the virus but not the host," Diamond added.

Viruses hijack host cells to replicate and spread, making them dependent upon the genetic material of the organisms they infect. 

If a cell lacks a gene that the virus requires for infection, the virus will have to stop in its tracks and will enable the cells to survive. Thus the missing gene becomes vital to spread of the virus.

"Flaviviruses appear to be uniquely dependent particularly on SPCS1 gene to release the viral particle," Diamond noted. 

For the study, published in the journal Nature, the team first conducted experiments on West Nile virus and then found that the same results held true for other Flaviviridae family members, including Zika, dengue, yellow fever, Japanese encephalitis and hepatitis C viruses.

Using gene-editing technology called CRISPR that is capable of selectively shutting down individual genes, the researchers identified only nine key genes that the virus relies on for infection or to spread. ​

​Hyderabad, June 18 (IANS) In a major boost for the Make in India initiative, US aerospace major Boeing and Tata Advanced Systems Limited (TASL) have joined hands to set up a facility here to co-produce fuselages for the Boeing AH-64 Apache helicopter and other aerostructures.

​New York, June 19 (IANS) Consuming high-quality plant-based diet such as whole grains, fruits, vegetables, nuts, seeds and legumes, can substantially lower the risk of developing Type 2 diabetes, says a new study led by an Indian-origin scientist.

The findings showed that eating a healthy version of such diet was linked with a 34 per cent lower diabetes risk, while a less healthy version -- including foods such as refined grains, potatoes, and sugar-sweetened beverages -- was linked with a 16 per cent increased risk.

Such diets are high in fibre, antioxidants, unsaturated fatty acids, and micronutrients such as magnesium and are low in saturated fat.

"The study highlights that even moderate dietary changes in the direction of a healthful plant-based diet can play a significant role in the prevention of type 2 diabetes," said Ambika Satija, professor at the Harvard T.H. Chan School of Public Health in Boston.

Adherence to a plant-based diet was found low in animal foods, with a 20 per cent reduced risk of Type 2 diabetes.

Healthy plant foods may also be contributing to a healthy gut microbiome, the authors said.

"A shift to dietary pattern marking higher plant-based foods and lower in animal-based foods, especially red and processed meats, can confer substantial health benefits in reducing risk of type 2 diabetes," added Frank Hu, Professor at Harvard Chan School.

The study, published in an online journal named PLOS Medicine, was the first to make distinctions between healthy plant-based diets and less healthy ones that include things like sweetened foods and beverages, and some animal foods, which may be detrimental for health.

The researchers conducted a 20 years survey of more than 200,000 male and female health professionals, and questioned them on their diet, lifestyle, medical history, and new disease diagnoses.

The diets of the participants were evaluated using a plant-based diet index, in which they assigned plant-derived foods in higher scores than animal-derived foods.

"These findings provide further evidence to support current dietary recommendations for chronic disease prevention," Satija suggested.​

New York, June 19 (IANS) Researchers have found that a perfect storm of a rapidly warming climate and human activities killed giant Ice Age species including elephant-sized sloth and powerful sabre-toothed cats that once roamed the plains of Patagonia.

Human activity that gradually lead to the warming of climate caused the extinction of the megafauna around 12,300 years ago, said the researchers.

"The study shows that human colonisation didn't immediately result in extinctions, but only as long as it stayed cold," said lead researcher Alan Cooper, professor at the University of Adelaide in Australia.

Species such as the South American horse, giant jaguar and sabre-toothed cat, and the enormous one-tonne short-faced bear (the largest land-based mammalian carnivore) were found widely across the South American country of Patagonia, but seemed to disappear shortly after humans arrived.

The pattern of rapid human colonisation through the Americas, coinciding with contrasting temperature trends in each continent, allowed the researchers to disentangle the relative impact of human arrival and climate change.

"More than 1,000 years of human occupation passed before a rapid warming event occurred, and then the megafauna were extinct within a hundred years," Cooper added in the paper published in the journal Science Advances.

The only large species to survive were the ancestors of present day llama and alpaca, the researchers said.

"The ancient genetic data show that only the late arrival in Patagonia of a population of guanacos from the north saved the species, all other populations became extinct," explained Jessica Metcalf from the University of Colorado-Boulder, in the US.

"In 1936 Fell's cave, a small rock shelter in Patagonia, was the first site in the world to show that humans had hunted Ice Age megafauna. So it seems appropriate that we're now using the bones from the area to reveal the key role of climate warming, and humans, in the megafaunal extinctions," noted Fabiana Martin from University of Magallanes in Chile.

The team studied ancient DNA extracted from radiocarbon-dated bones and teeth found in caves across Patagonia, and Tierra del Fuego, to trace the genetic history of the populations.​

New York, June 19 (IANS) Diminishing a person's belief in free will can lead them feeling less like their true selves and drive them to depression, finds a new study.

The findings showed that feeling alienated from one's true self can increase anxiety, depression and decision dissatisfaction.

"Whether you agree that we have free will or that we are overpowered by social influence or other forms of determinism, the belief in free will has truly important consequences," said lead author Elizabeth Seto, Student at Texas A and M University in the US.

On the other hand, knowing one's true self positively influences self-esteem and one's sense of meaning in life.

In addition, lack of free will may prompt people to behave without a sense of morality, particularly when one has a goal to improve the quality of life for individuals and the society at large.

"When we experience or have low belief in free will and feel 'out of touch' with who we are, we may behave without a sense of morality," Seto added in the study which was published in Social Psychological and Personality Science.

Previous studies have shown that minimising belief in free will can increase cheating, aggression, and conformity and decrease feelings of gratitude.

"Our findings suggest that part of being who you are is experiencing a sense of agency and feeling like you are in control over the actions and outcomes in your life," Seto explained.

"If people are able to experience these feelings, they can become closer to their true or core self," Seto said.

To influence the feeling of free will, the team randomly separated nearly 300 participants into groups and then asked questions to evaluate their sense of self.

Those in the low free will group showed significantly greater feelings of self-alienation and lower self-awareness than those in the high free will group.

In a follow-up study, a similarly sized group of participants experienced the same free will manipulation and were then presented a choice: keeping money for themselves or donating to a charity.

After making their decision, researchers asked them how authentic they felt about their decision.

The participants in low free will belief group reported less authenticity during the decision making task than their high freewill counterparts.​

New York, June 18 (IANS) Still waiting to hear from aliens and getting excited about the UFO sightings? Well, according to astronomers, extra-terrestrials are not likely to call the Earth for the next 1,500 years.

The team from Cornell University made this assumption by deconstructing the Fermi paradox and paring it with the mediocrity principle into a fresh equation.

The Fermi paradox says billions of Earth-like planets exist in our galaxy yet no aliens have contacted or visited us. 

Thus the paradox: the cosmos teems with possibility. 

The mediocrity principle is the idea that because we are not in any special location in the universe, we should not be anything special in the universe, physics.org reported.

“We haven't heard from aliens yet, as space is a big place. But that doesn't mean no one is out there," said Cornell student Evan Solomonides who presented the study at the American Astronomical Society's meeting in San Diego, California, recently.

Hunting for extra-terrestrials means sending out signals like television broadcasts, for example. 

As Earth's electronic ambassador, TV and radio signals are sent into space as a by-product of broadcast. 

Earth's broadcast signals have reached every star within about 80 light years from the Sun - about 8,531 stars and 3,555 Earthlike planets as our Milky Way galaxy alone contains 200 billion stars.

"Even our mundane, typical spiral galaxy - not exceptionally large compared to other galaxies - is vast beyond imagination," Solomonides added. 

"Those numbers are what make the Fermi Paradox so counterintuitive. We have reached so many stars and planets, surely we should have reached somebody by now, and in turn been reached … this demonstrates why we appear to be alone,” he added.

Combining the equations for the Fermi paradox and the mediocrity principle, the authors suggests Earth might hear from an alien civilisation when approximately half of the Milky Way Galaxy has been signalled in about 1,500 years.

Yervant Terzian, Cornell's Tisch Distinguished University Professor of Astronomy, is the co-author of the paper.​