Taxies in Dubai to promote Kerala Tourism

Washington D.C., Feb 6: An international team of astronomers has found an unusual monster galaxy that existed about 12 billion years ago when the universe was only 1.8 billion years old.

The team of astronomers was led by scientists at the University of California, Riverside.

Dubbed XMM-2599, the galaxy formed stars at a high rate and then died. Why it suddenly stopped forming stars is unclear.

"Even before the universe was 2 billion years old, XMM-2599 had already formed a mass of more than 300 billion suns, making it an ultra massive galaxy," said Benjamin Forrest, a postdoctoral researcher in the UC Riverside Department of Physics and Astronomy and the study's lead author.

"More remarkably, we show that XMM-2599 formed most of its stars in a huge frenzy when the universe was less than 1 billion years old and then became inactive by the time the universe was only 1.8 billion years old," Forrest added.

The team used spectroscopic observations from the W. M. Keck Observatory's powerful Multi-Object Spectrograph for Infrared Exploration or MOSFIRE, to make detailed measurements of XMM-2599 and precisely quantify its distance.

The study results appear in the Astrophysical Journal.

"In this epoch, very few galaxies have stopped forming stars, and none are as massive as XMM-2599," said Gillian Wilson, a professor of physics and astronomy at UCR in whose lab Forrest works.

"The mere existence of ultramassive galaxies like XMM-2599 proves quite a challenge to numerical models. Even though such massive galaxies are incredibly rare at this epoch, the models do predict them."

"The predicted galaxies, however, are expected to be actively forming stars. What makes XMM-2599 so interesting, unusual, and surprising is that it is no longer forming stars, perhaps because it stopped getting fuel or its black hole began to turn on. Our results call for changes in how models turn off star formation in early galaxies," the professor stated.

The research team found XMM-2599 formed more than 1,000 solar masses a year in stars at its peak of activity -- an extremely high rate of star formation. In contrast, the Milky Way forms about one new star a year.

"XMM-2599 may be a descendant of a population of highly star-forming dusty galaxies in the very early universe that new infrared telescopes have recently discovered," said Danilo Marchesini, an associate professor of astronomy at Tufts University and a co-author on the study.

"We have caught XMM-2599 in its inactive phase," Wilson said, who led the W. M. Keck Observatory data acquisition
Co-author Michael Cooper, a professor of astronomy at UC Irvine, said this outcome is a strong possibility.

"Perhaps during the following 11.7 billion years of cosmic history, XMM-2599 will become the central member of one of the brightest and most massive clusters of galaxies in the local universe," he said.

"Alternatively, it could continue to exist in isolation. Or we could have a scenario that lies between these two outcomes," he stated.

The study was supported by grants from the National Science Foundation and NASA.

Paris, Apr 17: Even as virologists zero in on the virus that causes COVID-19, a very basic question remains unanswered: do those who recover from the disease have immunity?

There is no clear answer to this question, experts say, even if many have assumed that contracting the potentially deadly disease confers immunity, at least for a while.

"Being immunised means that you have developed an immune response against a virus such that you can repulse it," explained Eric Vivier, a professor of immunology in the public hospital system in Marseilles.

"Our immune systems remember, which normally prevents you from being infected by the same virus later on."

For some viral diseases such a measles, overcoming the sickness confers immunity for life.

But for RNA-based viruses such as Sars-Cov-2 -- the scientific name for the bug that causes the COVID-19 disease -- it takes about three weeks to build up a sufficient quantity of antibodies, and even then they may provide protection for only a few months, Vivier told AFP.

At least that is the theory. In reality, the new coronavirus has thrown up one surprise after another, to the point where virologists and epidemiologists are sure of very little.

"We do not have the answers to that -- it's an unknown," Michael Ryan, executive director of the World Health Organization's Emergencies Programme said in a press conference this week when asked how long a recovered COVID-19 patient would have immunity.

"We would expect that to be a reasonable period of protection, but it is very difficult to say with a new virus -- we can only extrapolate from other coronaviruses, and even that data is quite limited."

For SARS, which killed about 800 people across the world in 2002 and 2003, recovered patients remained protected "for about three years, on average," Francois Balloux director of the Genetics Institute at University College London, said.

"One can certainly get reinfected, but after how much time? We'll only know retroactively."

A recent study from China that has not gone through peer review reported on rhesus monkeys that recovered from Sars-Cov-2 and did not get reinfected when exposed once again to the virus.

"But that doesn't really reveal anything," said Pasteur Institute researcher Frederic Tangy, noting that the experiment unfolded over only a month.

Indeed,several cases from South Korea -- one of the first countries hit by the new coronavirus -- found that patients who recovered from COVID-19 later tested positive for the virus.

But there are several ways to explain that outcome, scientists cautioned.

While it is not impossible that these individuals became infected a second time, there is little evidence this is what happened.

More likely, said Balloux, is that the virus never completely disappeared in the first place and remains -- dormant and asymptomatic -- as a "chronic infection", like herpes.

As tests for live virus and antibodies have not yet been perfected, it is also possible that these patients at some point tested "false negative" when in fact they had not rid themselves of the pathogen.

"That suggests that people remain infected for a long time -- several weeks," Balloux added. "That is not ideal."

Another pre-publication study that looked at 175 recovered patients in Shanghai showed different concentrations of protective antibodies 10 to 15 days after the onset of symptoms.

"But whether that antibody response actually means immunity is a separate question," commented Maria Van Kerhove, Technical Lead of the WHO Emergencies Programme.

"That's something we really need to better understand -- what does that antibody response look like in terms of immunity."

Indeed, a host of questions remain.

"We are at the stage of asking whether someone who has overcome COVID-19 is really that protected," said Jean-Francois Delfraissy, president of France's official science advisory board.

For Tangy, an even grimmer reality cannot be excluded.

"It is possible that the antibodies that someone develops against the virus could actually increase the risk of the disease becoming worse," he said, noting that the most serious symptoms come later, after the patient had formed antibodies.

For the moment, it is also unclear whose antibodies are more potent in beating back the disease: someone who nearly died, or someone with only light symptoms or even no symptoms at all. And does age make a difference?

Faced with all these uncertainties, some experts have doubts about the wisdom of persuing a "herd immunity" strategy such that the virus -- unable to find new victims -- peters out by itself when a majority of the population is immune.

"The only real solution for now is a vaccine," Archie Clements, a professor at Curtin University in Perth Australia, told AFP.

At the same time, laboratories are developing a slew of antibody tests to see what proportion of the population in different countries and regions have been contaminated.

Such an approach has been favoured in Britain and Finland, while in Germany some experts have floated the idea of an "immunity passport" that would allow people to go back to work.

"It's too premature at this point," said Saad Omer, a professor of infectious diseases at the Yale School of Medicine.

"We should be able to get clearer data very quickly -- in a couple of months -- when there will be reliable antibody tests with sensitivity and specificity."

One concern is "false positives" caused by the tests detecting antibodies unrelated to COVID-19.

The idea of immunity passports or certificates also raises ethical questions, researchers say.

"People who absolutely need to work -- to feed their families, for example -- could try to get infected," Balloux.

Feb 5: Tesla is making Elon Musk a lot richer without paying him a dime.

A blistering stock rally has bolstered the value of CEO Musk's 19% stake in the electric car maker by $16 billion since the start of 2020, to $30 billion.

Tuesday's steep climb in the share price could sweeten Musk's payday under his record-breaking compensation package, which is built on stock options that rely on market value targets. Two milestones have now been achieved that could see Musk unlock options worth $1.8 billion.

The controversial chief executive, who is also the majority owner and CEO of rocket maker SpaceX, recently testified that he did not have a lot of cash as he successfully defended himself in a defamation lawsuit. He previously has taken loans using his Tesla shares as collateral.

Musk does not take a salary, choosing instead a risky options package that envisions the stock market value of Tesla rising to $650 billion over 10 years, a prospect that was derided by some investors when the deal was announced in 2018.

That target now looks less crazy. Shares of Tesla have rallied over 50% since the company posted its second consecutive quarterly profit last Wednesday, which was viewed as a major accomplishment for a company competing against established automotive heavyweights including General Motors Co  and BMW.

Tesla shares have climbed about 400% since early June, helped by the company's better-than-expected financial results and ramped-up production at its new car factory in Shanghai.

On Tuesday, Tesla surged as much as 24% before falling back in the final minutes of the trading session to end the day up 13.7%. That put its market capitalization at $160 billion, almost twice the combined value of Ford Motor and General Motors.

The shares had also rallied on Monday, partly fueled by Panasonic Corp's 6752.T saying its automotive battery venture with Tesla was profitable for the first time.

The options Musk was awarded in 2018 vest incrementally based on targets for Tesla's stock market value and its financial performance. The market capitalization would have to sustainably rise by $50 billion increments over the agreement's 10-year period, with the full package payout reached if the market cap reaches $650 billion, as well as the company's meeting revenue and profit targets.

Musk is on his way to seeing his first two tranches of options vest. He achieved operational targets on revenue and adjusted earnings last year.

The rise in Tesla's market capitalization last month to a target of $100 billion opened the way for Musk's first tranche of options to vest. With Tuesday's surging share price, the market capitalization blew past the second target of $150 billion, opening the way for the second tranche to vest. Tesla's market capitalization must stay at or above each target level for one- and six-month averages for each set of options to vest.

Tesla was valued at about $52 billion when shareholders approved the pay package in March 2018, a time when the company faced a cash crunch, production delays and increasing competition from rivals.

A full payoff for Musk would surpass anything previously granted to U.S. executives, according to Institutional Shareholder Services, a proxy advisor that recommended investors reject the pay package deal at the time.

Musk currently owns about 34 million Tesla shares, and his compensation package would let him buy another 20.3 million shares if all his options tranches vest.

When Tesla unveiled Musk’s package, it said he could in theory reap as much as $55.8 billion if no new shares were issued. However, Tesla has since awarded stock to employees and last year sold $2.7 billion in shares and convertible bonds, diluting the value of the stock.

Musk has transformed Tesla from a niche car maker with production problems into the global leader in electric vehicles, with U.S. and Chinese factories. So far it has stayed ahead of more established rivals including BMW and Volkswagen.

Many investors remain skeptical that Tesla can consistently deliver profit, cash flow and growth. More Wall Street analysts rate Tesla "sell" than "buy," and the company's stock is the most shorted on Wall Street.