Knowledge Update

Washington, March 2 (IANS) In a first, scientists have measured rapidly varying temperatures in hot gas emanating from around a black hole and found that the winds can heat up and cool down in the span of just a few hours.

The findings, published in the journal Nature, could shed new light on how winds emanating from around a black hole can affect the environment of host galaxies.

For the study, the researchers used data from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) telescope and the European Space Agency's XMM-Newton telescope. 

"We know that supermassive black holes affect the environment of their host galaxies, and powerful winds arising from near the black hole may be one means for them to do so," said NuSTAR Principal Investigator Fiona Harrison, Professor at California Institute of Technology in the US.

"The rapid variability, observed for the first time, is providing clues as to how these winds form and how much energy they may carry out into the galaxy," Harrison said.

The black hole that the researchers observed is located in the active galaxy IRAS 13224-3809 in the constellation Centaurus.

To measure the temperatures of these winds created by disks of matter surrounding black holes, the team studied X-rays coming from the edge of the black hole. 

As they travel toward Earth, these X-rays pass through the winds, and some wavelengths of the X-ray spectrum are absorbed by different elements in the winds, such as iron and magnesium. 

By examining the holes, or "absorption features", in the X-ray spectrum as it reaches Earth, astronomers can learn more about the components of the wind.

While observing this spectrum, the team noticed that the absorption features were disappearing and reappearing in the span of a few hours. 

The team concluded that the X-rays were actually heating up the winds to very high temperatures so that they became incapable of absorbing any more X-rays. 

The winds then cool off, and the absorption features return, starting the cycle over again.

"This is the first time we have seen that winds are interacting with the black hole's radiation," study first author Michael Parker, postdoctoral scholar at University of Cambridge Institute of Astronomy in Britain

​New York, March 3 (IANS) NASA scientists have demonstrated that a new space weather warning system could help astronomers detect harmful solar particles much before they leave the sun's inner atmosphere -- critical extra time that could help protect astronauts in space.

Solar energy particles (SEPs) can move at nearly the speed of light -- so their total travel time can be less than an hour from the time they are accelerated near the sun to when they reach Earth.

In the study published in the journal Space Weather, scientists from NASA and the US National Center for Atmospheric Research, or NCAR, in Boulder, Colorado, showed how ground-based instruments called coronagraphs can help lengthen the warning time for solar particles.

Earth's magnetic field and atmosphere protect us on the ground from most of the harmful effects of space weather, but astronauts in low-Earth orbit -- or even, one day, in interplanetary space -- are more exposed to space weather, including bursts of fast-moving particles called solar energetic particles, or SEPs.

"Robotic spacecraft are usually radiation-hardened to protect against these kinds of events," said lead author on the study Chris St. Cyr, a space scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. 

"But humans are still susceptible," Cyr said.

So NASA wants to help improve systems that would provide future astronauts with advance warning of incoming SEPs. 

In the recent paper, the scientists showed that tracking an associated kind of solar explosion -- fast-moving clouds of magnetic solar material, called coronal mass ejections -- can help.

Scientists observe coronal mass ejections using a type of instrument called a coronagraph, in which a solid disk blocks the sun's bright face, revealing the sun's tenuous atmosphere, called the corona. 

Space-based coronagraphs are more widely used in space weather research because of their wide-field solar views that are not interrupted by cloud cover or Earth's rotation. 

But the new study showed that ground-based coronagraphs could improve the warning system.

​London, March 3 (IANS) Researchers have developed a new algorithm to identify the origin of irregular electrical 'storm waves' in the heart, a finding with major implications for the future treatment of a killer cardiac disease.

Atrial Fibrillation -- one of the most common forms of abnormal heart rhythm -- is caused by these waves and is a major cause of stroke as it increases the risk of blood clots forming inside the heart.

Current methods involve the use of a catheter to isolate the storm waves. However, this is very invasive surgery and it is extremely difficult to identify the origin of the waves in order to treat the condition, said researchers from UK's University of Manchester.

In the study, published in ther journal PLOS Computational Biology, researchers used a virtual human heart-torso and a 64-lead electrocardiogram (ECG) vest to study the correlation between the origin of the storm waves and the features of the ECG signals.

Using the properties of the atrial activation and the signals, they were able to develop a novel algorithm which could pin down the location of Atrial Fibrillation non-invasively, as well identifying different types of the condition.

"This technique can identify the origin of Atrial Fibrillation extremely effectively, which may provide a powerful tool for treatment in the future," said lead author Henggui Zhang, Professor at University of Manchester.

"The research, could lead to new developments to tackle heart problems more effectively and simply," Zhang added.

Atrial tachy-arrhythmias, including atrial fibrillation (AF), atrial tachycardia (AT) and flutter (AFL), are the most common cardiac arrhythmias, predisposing to heart attack, stroke and even possible cardiac death. 

Atrial fibrillation presents the greatest complexity and occurs in about 1-2 per cent of people and studies have shown that it is on the rise in the developed world due to the ageing population. 

London, March 3 (IANS) For the first time, scientists at the University of Cambridge have managed to create an artificial structure from stem cells that resembles a natural mouse embryo.

The findings could pave the way for developing artificial human life in the lab and help researchers understand why more than two out of three human pregnancies fail at the very early stages of embryo development.

Currently, embryos are developed from eggs donated through IVF clinics.

"We are very optimistic that this will allow us to study key events of this critical stage of human development without actually having to work on embryos. Knowing how development normally occurs will allow us to understand why it so often goes wrong," said lead researcher Magdalena Zernicka-Goetz, Professor at University of Cambridge.

For growing the mouse structure in culture, the researchers used two types of stem cells -- the body's 'master cells' -- and a 3D scaffold on which they can grow.

Previous attempts to grow embryo-like structures using only ESCs have had limited success.

This is because early embryo development requires the different types of cell to coordinate closely with each other.

However, in this study published in the journal Science, the researchers described how, using a combination of genetically-modified mouse embryonic stem cells and the extra-embryonic trophoblast stem cells, together with a 3D scaffold, they were able to grow a structure capable of assembling itself and whose development and architecture very closely resembled the natural embryo.

"Both the embryonic and extra-embryonic cells start to talk to each other and become organised into a structure that looks like and behaves like an embryo," Zernicka-Goetz said.

"It has anatomically correct regions that develop in the right place and at the right time," she added.

Comparing their artificial 'embryo' to a normally-developing embryo, the team was able to show that its development followed the same pattern of development. 

The stem cells organise themselves, with ESCs at one end and TSCs at the other. A cavity opens up within each cluster before joining together, eventually to become the large, so-called pro-amniotic cavity in which the embryo will develop, the researchers said. 

While this artificial embryo closely resembles the real thing, it is unlikely that it would develop further into a healthy foetus, the researchers said. 

To do so, it would likely need the third form of stem cell, which would allow the development of the yolk sac, which provides nourishment for the embryo and within which a network of blood vessel develops. 

In addition, the system has not been optimised for the correct development of the placenta, the researchers said.

New York, March 10 (IANS) Facebook has launched "Messenger Day" that let users share with the public or a custom friend decorated photos and videos that disappear after 24 hours.

​London, March 2 (IANS) Do you have a desk-bound job? Beware, you may be at a heightened risk of developing cardiovascular diseases by 0.2 per cent and an increase in waist circumference by two cm, for every additional hour of sitting on top of five hours, researchers warned. The findings showed that those who had desk jobs had a bigger waist circumference -- 97 cm compared to 94 cm in people without desk jobs. They also had approximately one body mass index (BMI) unit difference. Further, they had a higher risk of cardiovascular disease -- 2.2 per cent compared to 1.6 per cent in people without desk jobs, over ten years. In addition, each extra hour of sitting from five hours a day, increased the levels of bad cholesterol (LDL) and decreased good cholesterol (HDL). "Longer time spent in sedentary posture is significantly associated with larger waist circumference, higher triglycerides (fat in the blood) and lower HDL cholesterol, all adding up to worse risk of heart disease," said William Tigbe from University of Warwick in Britain. In contrast, walking more than 15,000 steps per day, which is equivalent to walking seven to eight miles, or spending seven hours per day upright, may be associated with zero risk factors, Tigbe added, in the paper published in the International Journal of Obesity. Although the study could be used as the basis of new public health targets for sitting, lying, standing and stepping to avoid metabolic risks, it would be very challenging to achieve unless incorporated into people's occupations. "Our evolution, to become the human species, did not equip us well to spending all day sitting down. We probably adapted to be healthiest spending seven to eight hours every day on our feet, as hunters or gatherers," said Mike Lean Professor at the University of Glasgow.

San Francisco, March 2 (IANS) Popular photo-sharing app Instagram on Thursday announced it will make available immersive, full-screen ads in its "Stories" feature for all businesses globally.

​Tokyo, March 2 (IANS) Leading professional services firm Cognizant on Thursday announced the acquisition of Brilliant Service Co. Ltd. -- a Japan-based intelligent products and solutions company that specialises in digital strategy, product design and engineering, Internet of Things (IoT) and enterprise mobility.

New York, March 2 (IANS) Wall Street closed with strong gains on Wednesday with the Dow Jones Industrial Average (DJIA), the main market indicator, rising 1.45 per cent and ending the day above 21,000 for the first time in history in the wake of President Donald Trump's address to a joint session of Congress.

​Washington, March 2 (IANS) NASA on Thursday released its 2017-2018 software catalog, which offers an extensive portfolio of software products for a wide variety of technical applications, all free of charge to the public, without any royalty or copyright fees.