Knowledge Update

​Washington, April 9 (IANS) US space firm SpaceX resumed its resupply mission to the International Space Station (ISS) on Friday, carrying aboard an experimental inflatable space habitat that might be crucial for future deep space explorations.

The California-based company also made history by landing the first stage of its Falcon 9 rocket on a droneship in the Atlantic Ocean, after it launched the Dragon spacecraft at 4:43 p.m. (2043 GMT) from Cape Canaveral Air Force Station in Florida, Xinhua reported.

This was SpaceX's eighth cargo mission to the ISS. It also marked the first flight of Dragon to the ISS since June, when the Falcon 9 rocket exploded about two minutes after liftoff.

As usual, SpaceX attempted to land the Falcon 9's first stage on the "Of Course I Still Love You" droneship, which was stationed in the Atlantic Ocean off the Florida coast.

Minutes later, the company posted a photo via Twitter in which the first stage was clearly seen standing on the deck of the ship.

It is the first time SpaceX has been able to stick a landing on a droneship after four previous such attempts ended in failure. It also achieved one successful soft landing on a land-based pad at Cape Canaveral in December last year.

What is different this time was "the rocket landed instead of putting a hole in the ship or tipping over. So we are really excited about that," said SpaceX founder Elon Musk at a press conference after the landing.

NASA offered a congratulation via Twitter to SpaceX for the successful landing and sending the unmanned Dragon to the orbiting laboratory.

Among the almost 7,000 pounds (3,200 kilograms) of items inside the Dragon spacecraft is the 3,100-pound (1,400-kilogram) Bigelow Expandable Activity Module (BEAM), a $17.8-million project that will be attached to the ISS to test the use of an inflatable space habitat in microgravity.

"It is the future," said Kirk Shireman, manager of NASA's ISS programme. 

"Humans will be using these kinds of modules as we move further and further off the planet and actually as we inhabit low Earth orbit."

According to NASA, inflatable habitats greatly decrease the amount of transport volume at launch for future space missions and take up less room on a rocket, but once set up, provide additional volume for living and working.

Shireman said the company that developed BEAM, Bigelow Aerospace, launched two inflatable modules about 10 years ago using Russian rockets but this will be the first time humans will interact with such a module.

After being attached to the ISS, BEAM will be filled with air to expand it for a two-year test period in which ISS astronauts will conduct a series of tests to validate overall performance and capability of expandable habitats.

BEAM is 5.7 feet (1.7 meters) long and 7.75 feet (2.4 meters) in diameter when packed; 12 feet (3.7 meters) long and 10.5 feet (3.2 meters) in diameter when expanded, with 565 cubic feet (16 cubic meters) of interior volume.

Bigelow Aerospace is also developing a new inflatable module called B330, which is 20 times larger than BEAM, and hopes to put two B330s together in orbit into a private space station in 2020, Robert Bigelow, the company's president, told reporters.

"We are in the early phase of a new kind of spacecraft that offers a lot of promise," Bigelow said.

The cargo also included new experiments that will help investigators study muscle atrophy and bone loss in space, seek insight into the interactions of particle flows at the nanoscale level and use protein crystal growth in microgravity to help design new drugs.

SpaceX is one of two US companies that provide ISS cargo services for NASA. The other company is Orbital ATK, whose Cygnus capsule was launched to the ISS on March 22.

It is the first time that both companies' cargo ships will be docked at the orbiting lab simultaneously.​

​London, April 9 (IANS) Nearly six-10 million years ago, the central Arctic was completely ice-free during summer and sea-surface temperature reached values of four to nine degrees Celsius, an international team of scientists has revealed.

They used unique sediment samples from the Lomonosov Ridge -- a large undersea mountain range in the central Arctic, while travelling on board Germany's research icebreaker RV Polarstern in 2014. 

"The Arctic sea ice is a very critical and sensitive component in the global climate system. It is therefore important to better understand the processes controlling present and past changes in sea ice," said study lead author Ruediger Stein from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI).

"One of our expedition's aims was to recover long sediment cores from the central Arctic, that can be used to reconstruct the history of the ocean's sea ice cover throughout the past 50 million years," Stein added.

Although the recovered sediment cores were only four to eight metres long, one of them turned out to be precisely one of those climate archives that the scientists had been looking for a long time. 

"With the help of certain microfossils, so-called dinoflagellates, we were able to unambiguously establish that the lower part of this core consists of approximately six to eight million-year-old sediments, thereby tracing its geological history back to the late Miocene," Stein said.

With the help of so-called "climate indicators or proxies", the scientists were able to to reconstruct the climate conditions in the central Arctic Ocean for a time period for which only very vague and contradictory information was available. 

The study, published in the journal Nature Communications, however, said that in spring, autumn and winter the ocean was covered by sea ice of variable extent.

"By combining our data records on surface water temperature and on sea ice, we are now able to prove for the first time that six to ten million years ago, the central Arctic Ocean was ice-free in the summer," Stein said. 

"In the spring and the preceding winter, on the other hand, the ocean was covered by sea ice. The seasonal ice cover around the North Pole must have been similar to that in the Arctic marginal seas today," he noted.​

​London, April 9 (IANS) Obesity and poor nutrition in mothers during pregnancy can affect the egg reserves of their female children, which can increase the risk of fertility problems, a study has found.

The researchers claimed this understanding to be the first step towards devising interventions to protect the fertility of females who experienced very difficult womb environments in the study conducted on mice.

"Infertility can have devastating impacts on individuals and families, and our study will help to better identify women who are at risk of experiencing problems with their fertility," said Catherine Aiken from University of Cambridge in Britain. 

"We hope to be able to devise ways to maintain future fertility for children who faced a very difficult nutritional environment in the womb," Aiken added in the paper published in the journal The FASEB.

This finding improves scientific understanding of the long-term, generational, effects of obesity and poor nutrition.

The team used mice and fed them with either a high-fat and high-sugar (obesogenic) diet or a normal healthy diet during pregnancy. After which, their female offspring were weaned onto the same obesogenic diet or normal diet. 

The results revealed that low egg reserves in all of the daughters whose mothers ate a high-fat and high-sugar diet, regardless the daughters' diet.

To find the cause of the low egg reserves, researchers examined the ovaries of the daughters and discovered changes that disrupted the normal protection against damaging free radicals in the ovaries, as well as energy production.

"It has of course long been known that the intrauterine environment is critical and also that maternal nutritional deprivation in particular can have very adverse effects on the offspring," said another researcher Thoru Pederson.

"However, this study shows that caloric excess also has adverse consequences and that to an extent it can affect is reduced ovulation, it constitutes a transgenerational defect that would be evolution”rily severe," Pederson explained.

Although rodent models can be different, it seems likely that these finding would translate to the humans and indeed such studies seeking this correlation would be highly warranted, the researchers suggested.​

New York, April 10 (IANS) Playing the same violent video game repeatedly reduces emotional responses -- like guilt -- not only to the original game, but to other violent video games as well, finds a new study.

Principal investigator Matthew Grizzard from the University of Buffalo said the reason why this happens remains a mystery. 

Gamers often claim that their actions in a video game are as meaningless to the real world as players capturing pawns on a chess board. Yet, previous research by Grizzard and others shows that immoral virtual actions can elicit higher levels of guilt than moral virtual actions. 

The study findings, published recently in the journal Media Psychology, seems to contradict claims that virtual actions are completely divorced from the real world. 

Grizzard's team wanted to replicate their earlier research and determine whether gamers' claims that their virtual actions are meaningless actually reflects desensitisation processes.

Although the findings of his study suggest that desensitisation occurs, mechanisms underlying these findings are not entirely clear.

Grizzard said his future research is working toward answering these questions.

"This study is part of an overarching framework that I've been looking at in terms of the extent to which media can elicit moral emotions, like guilt, disgust and anger," he said.​

​New York, April 10 (IANS) US researchers, led by an Indian-origin scientist, have developed a novel 3-D imaging tool that can provide highly accurate method to detect non-alcoholic fatty liver disease (NAFLD) that often begins without symptoms but can progress to cancer.

The researchers at the University of California, San Diego, conducted a prospective study of 100 patients (56 percent women) with biopsy-proven NAFLD to assess the efficacy of two-dimensional magnetic resonance elastography (MRE) and a novel 3D version. 

They found that both MRE technologies were highly accurate for diagnosing advanced fibrosis, with 3D perhaps providing additional capabilities in some patients.

"3D MRE is probably the most accurate non-invasive method to detect advanced fibrosis," said Rohit Loomba, the study's first author and director of the NAFLD Research Centre at UC San Diego School of Medicine.

MRE is a specialized version of magnetic resonance imaging (MRI) that propagates mechanical shear waves in liver tissue. An algorithm creates images that quantitatively measure tissue stiffness -- an indicator of fibrosis. 

The 2D version of MRE is already commercially available and easily implemented on basic MRI systems in clinics. Three-dimensional MRE is more technically demanding and not yet widely available.

The findings of the study, published recently in the American Journal of Gastroenterology, are encouraging because diagnosing NAFLD can be challenging. 

Current non-invasive techniques, such as molecular biomarkers in blood, are not sufficiently accurate for routine clinical use. Ultrasound-based methods have high failure rates, particularly in obese patients.

"These findings suggest that MRE could be used to enroll patients with advanced fibrosis into screening programs for cirrhosis as well as enrollment into clinical trials aimed at reversing fibrosis in the setting of advanced fibrosis," Loomba said.​

​Sydney, April 10 (IANS) A breakthrough chip for the nano-manipulation of light has pioneered new paths for developing next generation optical technologies and enabling deeper understanding of black holes.

Developed by a team of researchers at RMIT University in Melbourne, Australia, the integrated nanophotonic chip can achieve unparalleled levels of control over the angular momentum (AM) of light.

This means that now AM can be used at a chip-scale for the generation, transmission, processing and recording of information, and could also be used to help scientists better understand the evolution and nature of black holes.

While traveling approximately in a straight line, a beam of light also spins and twists around its optical axis. The AM of light measures the quantum of that dynamic rotation. 

Given the potential of using AM to enable the mass expansion of the available capacity of optical fibres, scientists have been trying to harness it on a chip scale.

"By designing a series of elaborate nano-apertures and nano-grooves on the photonic chip, our team has enabled the on-chip manipulation of twisted light for the first time," said Min Gu from RMIT University, who led the study that was published recently in the journal Science. 

"Our discovery could open up truly compact on-chip AM applications such as ultra-high definition display, ultra-high capacity optical communication and ultra-secure optical encryption," Gu added.

"It could also be extended to characterise the AM properties of gravitational waves, to help us gain more information on how black holes interact with each other in the universe," the researcher noted.​

London, April 10 (IANS) A formula taking into account the maximum mass of non-rotating neutron star has made it possible for scientists to calculate the critical mass when a rotating neutron star would collapse to become a black hole.

"It is quite remarkable that a system as complex as a rotating neutron star can be described by such a simple relation," said Luciano Rezzolla from the Goethe University in Frankfurt, one of the authors of the study.

Neutron stars have a mass that is up to twice that of the sun but a radius of only a dozen km, making them thousands of billions of times denser than that of the densest element on the Earth. 

But their mass cannot grow without bound. Indeed, if a non-rotating star increases its mass, its density also will increase. Normally this will lead to a new equilibrium and the star can live stably in this state for thousands of years. 

This process, however, cannot repeat indefinitely and the accreting star will reach a mass above which no physical pressure will prevent it from collapsing to a black hole. 

The critical mass when this happens is called the "maximum mass" and represents an upper limit to the mass that a non-rotating neutron star can be.

However, once the maximum mass is reached, the star also has an alternative to the collapse: It can rotate. 

A rotating star, in fact, can support a mass larger than if it was non-rotating, simply because the additional centrifugal force can help balance the gravitational force. 

Also in this case, however, the star cannot be arbitrarily massive because an increase in mass must be accompanied by an increase in rotation and there is a limit to how fast a star can rotate before breaking apart. Hence, for any neutron star there is an absolute maximum mass and is given by the largest mass of the fastest-spinning model.

Determining this value from first principles is difficult because it depends on the equation of state of the matter composing the star and this is still essentially unknown. Because of this, the determination of the maximum rotating mass of a neutron star has been an unsolved problem for decades. 

Scientists had to compute a very large number of stellar models to find the result, published recently in the journal Monthly Notices of the Royal Astronomical Society.

"Surprisingly, we now know that even the fastest rotation can at most increase the maximum mass of 20 percent at most," Rezzolla noted.

"This result has always been in front of our eyes, but we needed to look at it from the right perspective to actually see it," said Cosima Breu, a research student at the University of Frankfurt, who performed the analysis of the data during her bachelor thesis.

This simple but powerful result opens the prospects for more universal relations to be found in rotating stars. "We hope to find more equally exciting results when studying the largely unexplored grounds of differentially rotating neutron stars," Rezzolla said.​

​New York, April 10 (IANS) People with severe obesity who undergo bariatric surgery are likely to experience improvement in pain, physical function and walking ability, says a study.

The findings revealed that about 50-70 percent of adults experienced clinically significant improvements in perceived bodily pain and physical function and in objectively measured walking capacity.

The study's "large geographically diverse sample, inclusion of multiple validated measures of pain and physical function, longitudinal design, and follow-up through 3 years make it one of the most informative studies of pain and function following RYGB and LAGB to date," said Wendy C. King from the University of Pittsburgh in the US.

Severe obesity and excess weight can lead to joint damage and pain, resulting in limitations in walking and restricted other physical activities

The study, published in the journal JAMA, analysed 2,458 participants and was conducted at 10 hospitals. Of the participants, 79 percent were women with the median age 47 years and 2,221 completed baseline and follow-up assessments.

The assessments were conducted prior to surgery and annually thereafter.

Bariatric surgery is effective at achieving and maintaining weight loss, although the variability and durability of improvements in pain and physical function are not well described.

The team examined changes in pain and physical function in the first three years following bariatric surgery and factors associated with improvement, among adults with severe obesity.

Pre-surgery-to-post-surgery reductions in weight and depressive symptoms were associated with improvements in multiple outcomes.

About three-fourth of participants with severe knee and hip pain or disability at baseline experienced improvements in osteoarthritis symptoms.​

New York, April 10 (IANS) Researchers have determined that certain gastrointestinal tumours are more deadly than previously assumed.

Gastrointestinal stromal tumours (GISTs) may be malignant cancer or benign and are most commonly found in the stomach and small intestine and have significant variability in terms of size and malignant behaviour.

The finding, published online in the Journal of Gastrointestinal Surgery, showed that GISTs that are less than two cm cause 12.1 percent mortality rate for five years.

Also, up to 30 percent of patients have GISTs less than two cm in size, or slightly more than half an inch, the researchers noted.

More than 79 percent of patients have localised disease of GISTs, while for 11.4 percent the disease can spread to other regions. Previously, researchers did not expect any disease to have spread.

"While GISTs are rare, we have found that certain groups of these tumours result in a much higher mortality than expected," said Jason Sicklick, assistant professor at University of California-San Diego in US.

For the study, the team identified 378 patients with malignant GISTs of less than two cms between 2001 and 2011.​

London, April 11 (IANS) Ancestors of modern-day humans are thought to have wiped out the ancient Neanderthals from Europe by passing on diseases and infections when they moved out of Africa and into the continent previously dominated by them.

The Neanderthals, who would only have developed resistance to the diseases of their European environment, are most likely to have been infected with a bacterium that causes stomach ulcers, the virus that causes genital herpes, tapeworms and tuberculosis.

The researchers said that some infectious diseases are likely to be many thousands of years older than previously believed.

The diseases and infections to which the hunter-gatherers were exposed would have made them less able to find enough food and remain healthy. The diseases would have spread through sexual contact between the two species.

"Humans migrating out of Africa would have been a significant reservoir of tropical diseases," said Charlotte Houldcroft from the University of Cambridge in Britain.

"For the Neanderthal population of Eurasia, adapted to that geographical infectious disease environment, exposure to new pathogens carried out of Africa may have been catastrophic," Houldcroft added.

The findings showed Helicobacter pylori -- a bacterium that causes stomach ulcers -- as highly likely to have been passed by humans to Neanderthals. 

It is estimated to have first infected humans in Africa between 88,000 to 116,000 years ago, and in Europe 52,000 years ago.

Another likely candidate is herpes simplex 2 -- the virus that causes genital herpes. Evidence in the genome of this disease suggested that it was transmitted to humans in Africa 1.6 million years ago from another, currently unknown hominin species that in turn acquired it from chimpanzees.

The researchers have challenged the view that the spread of infectious diseases exploded with the evolution of agriculture about 8,000 years ago, which saw denser and more settled human populations coexisting with livestock.

Instead, genetic data showed that many infectious diseases have been "co-evolving with humans and our ancestors for tens of thousands to millions of years, and passed from them to the animals,” the researchers noted in the paper published in the American Journal of Physical Anthropology.

"Hunter-gatherers lived in small foraging groups. Neanderthals lived in groups of between 15-30 members, for example. So disease would have broken out sporadically, but have been unable to spread very far. Once agriculture came along, these diseases had the perfect conditions to explode, but they were already around,” Houldcroft maintained.

Recent theories for the cause of Neanderthal extinction range from climate change to an early human alliance with wolves resulting in domination of the food chain.

"It is probable that a combination of factors caused the demise of Neanderthals and the evidence is building that spread of disease was an important one," Houldcroft concluded.​