WASHINGTON (Reuters) - Pluto, a frigid little world inhabiting the solar system's outer reaches, may have been born as a warmer place sheltering a subsurface ocean that still exists today, researchers said on Monday.

An analysis of images of its surface taken in 2015 by NASA's New Horizons spacecraft and computer simulations of the dwarf planet's interior led the researchers to propose a "hot start" scenario for Pluto's formation some 4.5 billion years ago as the solar system, including Earth, took shape.

"When Pluto was forming, new material would have been coming in and impacting its surface. Each impact is like an explosion that would warm the nearby area," said University of California Santa Cruz planetary scientist Carver Bierson, lead author of the research published in the journal Nature Geoscience.

"If Pluto formed slowly, the surface would cool between each impact and generally stay very cold. If Pluto formed quickly, you have impact on top of impact and the surface doesn't have time to cool. We calculate that if Pluto formed in less than 30,000 years, the heat from these impacts could have been sufficient to lead to an early ocean," Bierson added.

Pluto, orbiting the sun about 40 times further than Earth in a region called the Kuiper Belt, may possess an icy outer shell hundreds of miles (km) thick atop an ocean of water perhaps mixed with salts and ammonia, with a solid rocky core below, Bierson said.

Under this scenario, parts of the ocean would gradually freeze over time. Water expands as it freezes, and cracks on Pluto's surfacing may be evidence of this. Pluto's surface temperature is about minus 480 degrees Fahrenheit (minus 230 degrees Celsius).

Because water is considered a vital ingredient for life, a subsurface ocean could make Pluto a long-shot candidate for harboring living organisms.

"Water could have been interacting chemically with the rocky core beneath the ocean, giving you more chemical ingredients to work with," Bierson added. "Are those the right ingredients for life? We don't know. We need to learn more about how life forms, or how life could form, to find these answers."

(Reporting by Will Dunham; Editing by Sandra Maler)

CHIAYI, Taiwan (Reuters) - A shimmering ring of light flashed into view on Sunday in parts of the eastern hemisphere as the moon drifted across the face of the sun in a rare eclipse on the longest day of the year.

The path of the eclipse spanned East Asia, South Asia, the Middle East and Africa. Most locations saw only a partial eclipse, with just a handful witnessing the true "ring of fire".

Unlike in a total eclipse, the moon in an annular, or ring-like, eclipse is unable to completely cover the sun, leaving a thin halo of light at its maximum phase.

Such an eclipse happens when the moon is farther away in its elliptical orbit around the Earth, appearing smaller as a result.

Hundreds of skywatchers gathered in an open space in Chiayi in southern Taiwan, one of the locations in Asia where the annular eclipse was visible.

"I'm more than 50 years old, so it's great that I could see this," said retiree Zhuang Yuhui, 56, who travelled to Chiayi from nearby Taichung city.

"I'm beyond excited."

In Taipei, groups of people gathered to view the eclipse through tinted glasses and their phones as the sky turned eerily darker.

"It's an astronomical miracle," said Elisa Chen, 29.

Solar eclipses on the summer solstice are rare. The last one was in June 2001.

But a "ring of fire" eclipse that falls exactly in midsummer - whether in the northern or southern hemisphere - is even more uncommon.

There have been none in at least 100 years, according to Reuters calculations based on NASA data.

The next one is in 2039, and then in 2392.

(Open NASA search engine https://eclipse.gsfc.nasa.gov/SEsearch/SEsearch.php in an external browser.)

(Reporting by Ann Wang; Additional reporting by Ben Blanchard and Ryan Woo; Editing by William Mallard)

WASHINGTON (Reuters) - Scientists have unearthed the first fossils of soft-shelled eggs laid by dinosaurs - two disparate species from Argentina and Mongolia - in a discovery suggesting that the earliest dinosaurs produced such eggs before some lineages turned to hard shells.

The embryo-containing eggs - leathery on the outside rather than hard and calcified like those of birds - belonged to a dinosaur from Patagonia called Mussaurus from about 200 million years ago and one called Protoceratops from the Gobi Desert from about 75 million years ago, researchers said on Wednesday.

It had long been thought that all dinosaurs laid hard-shelled eggs, as modern birds - the descendants of feathered dinosaurs - and crocodilians do. Many turtles, lizards and snakes lay soft-shelled eggs. But relatively few dinosaurs eggs had ever been found, and those belonged to only a handful of dinosaur groups including the meat-eaters.

Finding soft-shelled eggs in such dissimilar species living far apart in time and location indicates, the researchers said, that many lineages including the first dinosaurs to appear 230 million years ago may have laid such eggs. Soft-shelled eggs are not readily preserved as fossils.

Twenty-foot-long (6 meters) Mussaurus was an early member of the sauropod lineage of long-necked plant-eaters. Its 5-inch (13-cm) egg was rather spherical.

Sheep-sized herbivore Protoceratops was a member of the ceratopsian lineage of beaked dinosaurs, many of which had horns though not this one. Its 4-inch (10-cm) eggs were more oblong.

"This gives us a new perspective of the reproductive biology of dinosaurs, indicating that the basal dinosaurs (most primitive forms) were more primitive reptilian in their reproductive habits," said paleontologist Mark Norell of the American Museum of Natural History in New York, lead author of the research published in the journal Nature.

"This means that they laid soft-shelled eggs which were probably buried in the sand or in vegetation. It also explains why fossil calcified eggs are only known from a few groups of dinosaurs, and only appear long after the origin of the group."

(Reporting by Will Dunham; Editing by Sandra Maler)

(Reuters) - A mysterious 68-million-year-old fossil found on Seymour Island off Antarctica's coast that looked like a deflated football has turned out to be a unique find - the second-largest egg on record and one that may have belonged to a huge marine reptile that lived alongside the dinosaurs.

The fossilized egg - measuring 8 by 11 inches (29 by 20 cm) - is only slightly smaller than eggs of Madagascar's giant flightless elephant birds that went extinct only in the past several centuries, scientists said on Wednesday.

While birds, crocodilians and many dinosaurs laid hard-shelled eggs, the Antarctic egg had a soft, parchment-like shell.

"This new egg is the very first fossil egg from Antarctica, and the largest soft-shelled egg ever discovered," said University of Texas paleontologist Lucas Legendre, lead author of the research published in the journal Nature.

"It looks a bit like a deflated football: elongated, collapsed, with many creases and folds on its surface. One side is flattened, suggesting this is where it came in contact with the sea floor. Its eggshell is very thin and poorly mineralized, like in the eggs of lizard and snakes."

The only creatures in Antarctica at that time large enough to lay such an egg were seagoing reptiles: the marine lizards called mosasaurs and the long-necked plesiosaurs. The fossil challenges the notion that these animals did not lay eggs and were fully viviparous, giving birth to live young.

"We suspect these large reptiles had the same reproductive strategy as viviparous lizards and snakes, which lay eggs with a very thin shell that hatch immediately after being laid," Legendre said.

The egg had no embryonic remains and the mother's skeleton was not found to identify what animal laid it. Among the candidates are species of mosasaurs reaching 50 feet (15 meters) long and plesiosaurs reaching 33 feet (10 meters) long, Legendre said.

Mosasaurs and plesiosaurs went extinct at the same time as the dinosaurs after an asteroid struck Earth 66 million years ago.

Scientists from the University of Chile and the country's Museum of Natural History found the fossil in 2011. Initially bewildered by it, they nicknamed it "The Thing," after the name of a science-fiction film.

"When we arrived at camp we asked the geologists that accompanied us if they had ever seen anything like it," said University of Chile paleontology researcher Rodrigo Otero. "Their expression of bewilderment said it all."

(Reporting by Will Dunham in Washington and Dave Sherwood in Santiago; Editing by Lisa Shumaker and Sandra Maler)

The official website for the Beidou network said in a statement that problems were detected during pre-launch tests of the Long March-3B booster and that the new launch date would be determined later. It did not offer specifics on the problems or the launch date.

The Beidou-3 satellite was expected to be the 35th and final satellite of the Chinese navigation system - an estimated $10 billion project meant to be Beijing's answer to the U.S.-owned Global Positioning System.

When completed, China says, the system will keep military communications secure and improve weapons targeting, especially in the Asia-Pacific region.

Beidou also has major civilian applications. More than 70% of mobile phones in China were Beidou-enabled as of 2019, state media reported, including models made by Huawei [HWT.UL], Oppo, Xiaomi, Vivo and Samsung. Millions of taxis, buses and trucks use Beidou signals.

China's satellite navigation sector may top 400 billion yuan ($57 billion) in value this year, Chinese state media have reported.

(Reporting by Se Young Lee. Editing by Gerry Doyle)

Under the contract, KBR will perform International Space Station payload operations and support the testing of NASA's flagship space launch system.

NASA is leaning heavily on private companies built around shared visions for space exploration, as it gears up for a long-term presence on the moon and prepares for a manned mission to Mars.

The space launch system, set to debut next year, is currently NASA's ride for transporting humans from the Earth to the moon by 2024.

KBR, which until April 2007 was the engineering and construction arm of oilfield services giant Halliburton Co, said on Monday its work would support various NASA programs, payload developers, educational institutions, international partner space agencies and commercial partners.

(Reporting by Akanksha Rana in Bengaluru; Editing by Ramakrishnan M.)

They plan to collect 300 bats over three days from a cave in the Chanthaburi province in the southeast of the country. The bats will be released following the tests.

Thailand has 23 species of the horseshoe bat, but there has not been an investigation before.

The source of the virus remains a matter of debate after it emerged in China late last year.

The World Health Organization (WHO) in April said that all available evidence suggests that it originated in bats in China, but it was not clear how the virus had jumped the species barrier to humans.

The research team in Thailand includes Supaporn Wacharapluesadee, who identified the country's first case of COVID-19 in January.

“The reason we need to investigate the horseshoe bat is because there are reports from China that the COVID-19 virus is similar to the virus found in the horseshoe bat,” Supaporn said.

Thailand was the first country outside China to record a case of the virus. It has so far reported 3,134 cases and 58 deaths.

Researchers from the National Parks Department, Chulalongkorn Hospital and Kasetsart University entered the cave on Thursday evening and re-emerged in the early hours of Friday with samples of bat blood, saliva and feces.

Investigators were concerned that villagers in the area could be at risk of infection.

Locals have been known to eat bats, Supaporn said, adding adequate education and information programs were needed.

Local transmissions have waned in recent weeks with new cases coming from Thais returning from overseas.

(Refiles to add dropped letter in headline)

(Reporting by Jiraporn Kuhakan and Chayut Setboonsarng; Editing by Clelia Oziel)

POSTOJNA, Slovenia (Reuters) - Three rare aquatic creatures known as baby dragons are going on display in an aquarium at Slovenia's Postojna Cave, one of the country's biggest tourist attractions.

The cave-dwelling animals, officially called proteus or olms, have pale pink skin, no eyesight, a long thin body and four legs. They live only in the waters of dark caves of the southern European Karst region.

Local people used to believe the creatures, which were sometimes forced into the open by high water, were the babies of dragons that were believed to live in the caves.

At the Postojna Cave, Europe's largest cave open to tourists, staff were able to observe the baby dragons being born in 2016.

"We were excited when the eggs were being laid and then had thousands of doubts: how will they survive, what will we feed them with, how will we protect them from infection?" Marjan Batagelj, managing director of the cave, told Reuters.

"Science said they had a 0.5% chance of survival ... but we managed to bring up 21 of them," he added. A total of 64 eggs were laid in 2016.

The babies are up to 14 centimetres (5 inches) long and will reach 30 centimetres (12 inches) when fully grown. Olms can survive up to 8 years without food and have a lifespan of up to 100 years.

A special laboratory has been set up in the cave where the baby dragons are being monitored before they are all presented to the public.

(Reporting by Marja Novak; Editing by Giles Elgood)

BEIJING (Reuters) - The Chinese Beidou navigation network will be complete this month when its final satellite goes into orbit, giving China greater independence from U.S.-owned GPS and heating up competition in a sector long dominated by the United States.

The idea to develop Beidou, or the Big Dipper in Chinese, took shape in the 1990s as the military sought to reduce reliance on the Global Positioning System (GPS) run by the U.S. Air Force.

When the first Beidou satellites were launched in 2000, coverage was limited to China. As use of mobile devices expanded, China in 2003 tried to join the Galileo satellite navigation project proposed by the European Union but later pulled out to focus on Beidou.

In the age of the iPhone, the second generation of Beidou satellites went operational in 2012, covering the Asia-Pacific.

China began deploying the third generation of satellites aimed at global coverage in 2015.

The 35th and final Beidou-3 satellite will be launched this month - the day has yet to be announced - meaning Beidou has more satellites in its system than GPS's 31, and more than Galileo and Russia's GLONASS.

With estimated investment of $10 billion, Beidou keeps the communications network of the Chinese military secure, avoiding the risk of disruption to GPS in the extreme event of conflict.

Weapons targeting and guidance also improves. When complete, Beidou's location services are accurate down to 10 cm in the Asia-Pacific, compared with GPS's 30-cm range.

"Beidou was obviously designed a few decades after GPS, so it has had the benefit of learning from the GPS experience," said Andrew Dempster, director of the Australian Centre for Space Engineering Research.

"It has some signals that have higher bandwidth, giving better accuracy. It has fewer orbit planes for the satellites, making constellation maintenance easier."

SPACE SILK ROAD

Beidou-related services such as port traffic monitoring and disaster mitigation have been exported to about 120 countries, state media reported.

Many of those countries are involved in the Belt and Road initiative, spearheaded by President Xi Jinping to create a modern-day Silk Road of trade and investment.

In a 2019 report, the U.S. congressional U.S.-China Economic and Security Review Commission warned that China promoted launch services, satellites and Beidou under its "Space Silk Road" to deepen reliance on China for space-based services, potentially at the expense of U.S. influence.

Thailand and Pakistan were the first foreign countries to sign up for Beidou's services, in 2013.

Within China, more than 70% of mobile phones were Beidou-enabled as of 2019, state media reported, including models made by Huawei [HWT.UL], Oppo, Xiaomi, Vivo and Samsung.

Millions of taxis, buses and trucks were also able to receive Beidou signals.

China's satellite navigation sector may top 400 billion yuan ($57 billion) in value this year, state media said.

Ahead of the Beidou-3 completion, satellite-related shares have soared.

Beijing BDStar Navigation Co, which makes chips that receive Beidou signals, has surged 34.4% this year. Hwa Create leapt 52.3%, outpacing the 7.6% gain in the Shenzhen benchmark.

(Reporting by Ryan Woo and Liangping Gao; Additional reporting by Josh Horwitz and Yilei Sun; Editing by Robert Birsel)

SANTIAGO (Reuters) - Chilean and Argentine researchers have unearthed teeth in far-flung Patagonia belonging to a mammal that lived 74 million years ago, the oldest such remains yet discovered in the South American country, the Chilean Antarctic Institute reported on Thursday.

Scientists uncovered the tiny teeth, which belonged to a species called Magallanodon baikashkenke, on a dig near Torres del Paine National Park, a remote area of Patagonia famous for its glacier-capped Andean spires and frigid ocean waters.

The small mammal would have lived in southern Patagonia during the late Cretaceous era, alongside dinosaurs, crocodiles, turtles and birds, according to an article published in the bulletin of the Natural History Museum of Chile.

It is the southernmost record of Gondwanatheria, a group of long-extinct early mammals that co-existed with dinosaurs.

Alexander Vargas, a researcher at the University of Chile, described the mammal as an evolutionary stepping stone between "egg-laying mammals, like the platypus ... and marsupial mammals."

Vargas said the beast was not a rodent but had evolved "rodent-like chewing teeth."

Gondwanatheria remains from the Cretaceous era are extremely rare, particularly in this part of southern South America, according to the Chilean Antarctic Institute.

(Reporting by Fabian Cambero, writing by Dave Sherwood; Editing by Steve Orlofsky)

WASHINGTON (Reuters) - A tiny statuette of a bird carved from burnt bone about 13,500 years ago reveals the origins of Chinese art, embodying a style different from prehistoric three-dimensional artwork by people in other parts of the world, researchers said on Wednesday.

The figurine, found at a site called Lingjing in Henan Province in central China, depicts a standing bird on a pedestal and was crafted using stone tools employing four sculpting methods - abrasion, gouging, scraping and incision, the researchers said.

It is the oldest-known three-dimensional art from China and all of East Asia by 8,500 years, although there are primitive abstract engravings on bone and stone and personal ornaments made of animal teeth and shells predating it.

The bird sculpture, the product of an Ice Age hunter-gatherer culture, is six-tenths of an inch (1.5 cm) long, apparently representing a songbird.

"Examining this figurine under the microscope and looking at its high-resolution 3D reconstruction is a moving experience. It opens a window on micro-gestures made by a great artist," said archeologist Francesco d'Errico of the French National Centre for Scientific Research, who is also attached to the Universities of Bordeaux and Bergen.

Humankind's earliest-known three-dimensional carvings, made of mammoth ivory, date to 40,000 years ago from southern Germany.

The bird was so expertly crafted from the bone of an unidentified mammal that the artist made the tail slightly oversized so the figurine would not fall forward, indicating an understanding of achieving balance, said d'Errico, a senior author of the research published in the journal PLOS ONE.

It is still unclear whether three-dimensional artwork arose independently in various locales or by diffusion from a prehistoric center of origin. The figurine differs in size, style and technology from older and contemporaneous carvings from Europe and Siberia, d'Errico said, suggesting it belongs to a distinctive Chinese artistic tradition.

(Reporting by Will Dunham; Editing by Peter Cooney)

LONDON (Reuters) - Scientists have used human embryonic stem cells to create an embryo-like research model to help them study some of the earliest stages of human development.

The model overcomes some of the ethical restrictions on using human embryos for research and will allow scientists to study a period of human development known as the "black box" period, which they say has never been directly observed before.

"Our model produces part of the blueprint of a human," said Alfonso Martinez-Arias, a professor at Britain's Cambridge University who co-led the project.

"It's exciting to witness the developmental processes that until now have been hidden from view - and from study."

The hope, he said, is that understanding these processes could reveal the causes of human birth defects and diseases, and lead to the development of tests for them in pregnant women.

The blueprint of an organism arises through a process known as "gastrulation", which in humans begins around two weeks into development. Gastrulation is referred to as the 'black box' period of human development, because legal restrictions prevent the culture of human embryos in the lab beyond day 14.

Experts not directly involved in the work - due to be published in the journal Nature on Thursday - said it was an important step towards deepening understanding of human life.

"This work adds to the 'in vitro toolkit' that scientists can now use to study the most unknown stages of human pregnancy – between weeks 2 and 4, where women wouldn’t normally know if they are pregnant," said Teresa Rayon, a specialist at The Francis Crick Institute.

Previous embryo-like models created from mouse stem cells are limited in what they can tell scientists about human development.

For this work, Martinez-Arias' team made gastruloids in a lab using human embryonic stem cells and treating them with chemical processes.

Gastruloids have no potential to develop into fully-formed embryos. They do not have brain cells or any of the tissues needed for implantation into the womb, which means they would never be viable beyond very early stages and therefore conform to ethical standards, the researchers said.

(Reporting by Kate Kelland, editing by Gareth Jones)

Australian scientists determined that there were about 64,000 green turtles waiting to lay eggs on Raine Island - a vegetated coral cay on the outer edges of the Great Barrier Reef - significantly more than thought.

"When we compared drone counts to observer counts we found that we had under-estimated the numbers in the past by a factor 1.73," Richard Fitzpatrick, research partner at Biopixel Oceans Foundation said in an emailed statement.

The research is good news for scientists concerned about declining numbers of green turtles.

Listed as endangered, many countries have made it illegal to collect or harm them, while nesting grounds are often also protected.

But getting an accurate picture of how the species is responding to protection efforts has been difficult.

Previously, researchers would paint a non-toxic white stripe down the turtles' shells and would count them, those with and without white stripes, from a small boat. But this way of counting proved inaccurate due to poor visibility, the researchers said.

(Reporting by Colin Packham; Editing by Robert Birsel)

The United States launched the first astronauts from U.S. soil since 2011 last month in a rocket built by SpaceX, the company of billionaire entrepreneur Elon Musk. In the intervening years, Americans flying to the International Space Station relied on Russian Soyuz spacecraft.

In a column in this week's Russian version of Forbes, Dmitry Rogozin, the head of Roscosmos, lamented that Americans still do not take the Russian space program as seriously as their own.

"When our partners finally managed to conduct a successful test on their spacecraft, there were nothing but jokes and mockery directed at us," Rogozin complained. Instead, the American space industry should have thanked Russia.

"Our country was the first to send a man into space," Rogozin wrote. "We remain first to this day."

Roscosmos has in recent years suffered a series of setbacks and corruption scandals, including during the construction of the Vostochny Cosmodrome in the country's far east.

It criticized U.S. President Donald Trump's "hysteria" after he said the SpaceX launch showed the United States had regained its place as the world's leader in space.

Trump also said U.S. astronauts would soon land on Mars, and that Washington would soon have "the greatest weapons ever imagined in history."

(Reporting by Gabrielle Tétrault-Farber)

"The coronavirus has created a need for robots because they can reduce direct contact between people," Ken Matsui told Reuters at his company's workshop in Kawasaki, near Tokyo. "We've had inquiries from overseas, including from Singapore and France."

The latest feature of the remote-controlled or so-called avatar robot is a hand attachment that uses ultraviolet light to kill viruses on door handles.

An unprecedented population decline that is shrinking Japan's workforce by more than half a million people a year as well as a reluctance to bring in foreign labor to fill vacant positions has spurred robot development in Japan.

The emergence of coronavirus-related demand could further that work.

Mira Robotics' Ugo is a pair of height-adjustable robotic arms mounted on wheels, operated remotely through a wireless connection with a laptop and game controller. A range-measuring laser mounted on the base helps it navigate, while a panel at the top displays eyes to give it a friendlier appearance.

It takes around 30 minutes to learn how to use the robot, with each operator able to control as many as four machines, said Matsui. Ugo which costs around $1,000 a month to rent, can be deployed as a security guard, carry out equipment inspections and clean toilets and other areas in office buildings, he added.

Matsui's two-year old startup so far has only one ugo operating at an office building in Tokyo.

(Reporting by Tim Kelly and Kim Kyung Hoon; Editing by Christopher Cushing)

WASHINGTON (Reuters) - In a glimpse into the future of archeology, researchers have used ground-penetrating radar to map an entire ancient Roman city, detecting remarkable details of buildings still deep underground including a temple and a unique public monument.

The technology was used at Falerii Novi, a walled city spanning 75 acres (30.5 hectares) about 30 miles (50 km) north of Rome, researchers said on Monday.

Falerii Novi was founded in 241 BC during the time of the Roman Republic and was inhabited until around 700 AD in the early Middle Ages.

It marked the first time a complete ancient city was mapped using ground-penetrating radar (GPR), which lets researchers explore large-scale archeological sites expeditiously without excavation, which can be costly and time-consuming.

The technology can "see" beneath the surface using a radar antenna that sends a pulsed radio signal into the ground and listens for the echoes bouncing off objects. The GPR equipment was pulled over the surface using an all-terrain vehicle.

"This took one person about three to four months in the field," said Martin Millett, a University of Cambridge classical archaeology professor who helped lead the study published in the journal Antiquity. "This really does change how we can study and understand Roman towns - the way of the future for archaeology."

Falerii Novi, not quite half the size of ancient Pompeii, had previously been partially excavated but most remained buried. With a population of perhaps 3,000 people, it boasted an unexpectedly elaborate public bath complex and market building, at least 60 large houses and a rectangular temple with columns near the city's south gate.

Near the north gate was a public monument unlike any other known, with a colonnaded portico on three sides and a large open square measuring 130 by 300 feet (40 by 90 meters). Falerii Novi had a network of water pipes running beneath the city blocks and not just along streets, indicating coordinated city planning.

(Reporting by Will Dunham; Editing by Sandra Maler)

NEW YORK (Reuters) - Eleven years ago, environmental scientist Jesse Ausubel dreamed aloud in a commencement speech: What if scientists could record the sounds of the ocean in the days before propeller-driven ships and boats spanned the globe?

They would listen to chit-chat between blue whales hundreds of miles apart. They would record the familiar chirps and clicks among a pod of dolphins. And they would do so without the cacophony of humankind – and develop a better understanding of how that undersea racket has affected sea life.

It was a flight of fancy, more aspirational and inspirational than a plan.

At first, Ausubel says, he (very fancifully) suggested a year of a "quiet ocean," during which shipping would come to a halt, or at least slow down. Then a month. And finally, just a few hours.

As far-fetched as even that was, a small fraternity of about 100 similarly curious scientists picked up on his vision. In 2015, they published a plan of how to conduct the International Quiet Ocean Experiment, should the opportunity ever present itself.

When the COVID-19 pandemic sparked an extreme economic slowdown in March, sending cruise ships to port and oil tankers to anchor, they mobilized. Last month, they finished cobbling together an array of 130 underwater hydrophone listening stations around the world – including six stations that had been set up to monitor underwater nuclear tests.

"Well, we're not excited that COVID happened, but we're happy to be able to take advantage of the scientific opportunity," says Peter Tyack, a professor of marine mammal biology at the University of St. Andrews in Scotland and one of the early instigators. "It would have just been impossible any other way."

Tyack says the recordings should give scientists a never-before glimpse of the ocean with little human interference. It's a bit like looking at the night sky if most of the world's lights were turned off.

He says some research suggests large whales have adapted to man-made noises by raising their voices and their pitch. He speculates that many species also have moved to quieter regions of the world so they can find food, and one another, more easily.

Generally, the group will be looking to see if the whales and other sea mammals adapt to the quieter oceans by lowering their volume, communicating more efficiently or shifting their habitat.

Some of the project's listening posts are connected to land via cables, but many of them are not and the recordings have to be retrieved by ships. Now that economies around the world are reopening, the quiet oceans group has started gathering the soundscape data.

It won't be until the end of the year, however, that the researchers will have cleaned up the recordings and can compare them to previous years for changes in human and animal noise alike.

The focus of the serendipitous project is on the so-called SOFAR (Sound Fixing and Ranging) channel, a naturally occurring ocean stratum in which sound can travel long distances.

It's where large baleen and fin whales sing for a lover or join in a friendly chorus. But it's also where the human racket from fishing boats, tankers and motorboats, as well as oil rigs and wind turbines, gets trapped and then propagated around the world.

Sound waves travel farther and faster in water than in the air. That's especially true of the bass notes of a whale's song, the low grinding of a ship's shaft, even the rumble of a nuclear explosion. Those sounds can travel hundreds or even thousands of miles, bending around the planet by bouncing up and down in the SOFAR channel, a kilometer-deep band of water.

The 130 recording stations used by the researchers are a hodgepodge of locations and sensitivity in that channel. Part of the planning process includes identifying and recruiting partners who operate listening stations run by governments, universities, environmental groups and other agencies.

The humblest station is four kilometers off the Spanish coast and operated by the Polytechnic University of Barcelona. It records sound up to 10 kilometers away. At the other extreme are six stations, each with multiple hydrophones, operated by the Vienna-based Comprehensive Nuclear Test Ban Treaty Organization. Those stations can not only pinpoint underwater nuclear explosions anywhere on the planet, but also eavesdrop on whales an ocean away.

Ausubel, the director of the Program for the Human Environment at New York's Rockefeller University, says he and his fellow dreamers were ready, even if their plan seemed unrealistic.

"We spent a lot of time planning: How would you try to set up this kind of study, even though we realized that it wasn't really practical?"

But the plan, Ausubel says, anticipated moments of opportunity such as an extreme weather event, not a pandemic.

"Immediately after a hurricane or a typhoon, it's very quiet for a day or two because of the fear of large waves or storms," he says. "Fishermen don't go out to sea; shipping routes are changed; oil and gas platforms may be shut down."

Amid the pandemic and the lockdowns that ensued, major ports in the Northeast of the United States, such as Boston, Philadelphia, New York and Baltimore, saw a nearly 50% drop in ship and boating traffic in April compared to the same month in 2019, according to MarineTraffic, a ship-tracking firm.

Large European ports, such as Lisbon, Antwerp, Le Havre and Rotterdam, saw about a 25% drop in the same month, the firm said.

"I think there'll be some variability in different places, which is quite important to test this," Tyack says. "It isn't really a controlled experiment, so it's better to have 50 different sites, some of which noise is much lower and some of which it isn't, to be able to look at the impact of the reduction."

Still, Ausubel says he already sees anecdotal evidence that marine mammals are changing their behavior.

"There have been observations near Vancouver of orcas coming closer to the city than was customary, and off Scotland," he says.

Orcas, dolphins and humpback whales, which communicate using high-frequency sounds that don't travel particularly far, often congregate in shallower waters. They may have moved closer to once-busy ports and harbors, he speculated.

The group hopes to publish a paper this summer that gathers anecdotal reports of changes observed in recent months. At the end of the year, a group led by Tyack will report how much the volume went down. And finally, next year, the researchers aim to publish a full analysis of how the reduction in sound changed the behavior of marine mammals and other marine life.

"What did the pre-industrial ocean sound like," Tyack says, "and how are marine ecosystems going to respond to that?"

(Reporting by Maurice Tamman, editing by Kari Howard)

After immunizing Tyson, a 12 year-old alpaca in Germany, with virus proteins, the team at the Karolinska Institute have isolated tiny antibodies - known as nanobodies - from his blood that bind to the same part of the virus as human antibodies and could block the infection.

They hope this can form the basis of a treatment for COVID 19 or eventually a vaccine against it, though the work is at an early stage.

"We know that it is the antibodies that are directed to the same very, very precise part of the virus that are important and that is what we have engineered with this antibody from Tyson," Gerald McInerney, head of the team at Karolinska said.

"In principle, all the evidence would suggest it will work very well in humans, but it is a very complex system."

Llamas and other members of camel family - as well as sharks - are known to produce nanobodies, which are far smaller than the full-size antibodies produced by humans, and therefore potentially easier for scientists to work with.

A vaccine may still be some way off.

"We will now move forward to going into in-vivo studies, maybe with mice or hamsters or other animals that can be used as a model for COVID 19 disease, but the next step after that we really can't say," McInerney said.

As for Tyson, he has done his job.

"Tyson is 12 years old, I believe, and he may be looking at retirement soon," McInerney said. "So he'll live out his life on his farm back in Germany."

(Reporting by Philip O'Connor; Writing by Simon Johnson; Editing by Peter Graff)

LONDON (Reuters) - Scientists are resuming COVID-19 trials of the now world-famous drug hydroxychloroquine, as confusion continues to reign about the anti-malarial hailed by U.S. President Donald Trump as a potential "game-changer" in fighting the pandemic.

The renewed research push follows widespread criticism of the quality of data in a study that on Thursday was retracted. The article, originally published in influential medical journal The Lancet, had found high risks associated with the treatment.

The World Health Organization, which last week paused trials when The Lancet study showed the drug was tied to an increased risk of death in hospitalized patients, said on Wednesday it was ready to resume trials.

The WHO's change of mind is "a wise decision", according to Martin Landray, co-lead scientist on the Recovery trial, the world's largest research project into existing drugs that might be repurposed to treat COVID-19 patients.

"What all this episode really reflects is that without randomised trials, there is huge uncertainty," said Landray, a professor of medicine and epidemiology at Oxford university.

Randomised studies are the gold standard in research, randomly assigning a treatment to one group of people and a dummy to another group so that the two can be compared. The Lancet study was a "retrospective observational" study, using a data set from an analytics firm, to see what effects the drug had had on some COVID-19 patients, compared to those who did not get it.

The WHO's about-face came after nearly 150 doctors signed a letter to the Lancet outlining concerns about the data of the observational study published on May 22. On Thursday three of the study's authors retracted it, saying the company holding the data would not release it for an independent review.

Some scientists said the episode had set back efforts to determine whether hydroxychloroquine was an effective or risky treatment for COVID-19, as some other trials around the world were also halted following the WHO's initial decision to pause.

"It's really impacted quite negatively the sort of studies that would be able to say if there is a benefit or harm," Will Schilling told Reuters. He is co-lead on the UK COPCOV study which was paused last week, just days after its launch.

"At the moment, we don't really know," Schilling said. "That's why these studies are needed, and now they've been slightly waylaid by all of this."

Scientists acknowledge, though, that studies are being conducted at break-neck speed while garnering unprecedented levels of attention that could give findings unwarranted weight.

THE PRESIDENT'S TAKING IT

Hydroxychloroquine has made global headlines in large part because of its promotion by Trump, who said in March it could be a game-changer and last month revealed he was taking it himself, even after the U.S. Food and Drug Administration (FDA) had advised that its efficacy and safety were unproven.

In the absence of clear scientific evidence, some authorities and consumers are buying up stocks of the drug in case it turns out to be effective. Britain, for example, is spending millions of pounds bulk-buying tablets.

Hydroxychloroquine was shown in laboratory experiments earlier this year to be able to block the SARS-CoV-2 virus that causes COVID-19, but this effect has not been replicated in rigorous trials in people.

A separate study by University of Minnesota scientists of the potential preventative effect of hydroxychloroquine against the new coronavirus found it did not protect people who had been given it after being exposed to COVID-19.

Here again, though, the waters have been muddied. The New England Journal of Medicine, which published the research on Wednesday, noted in an editorial, that there were limits to the scope of the study.

The University of Minnesota study also was limited in the scenario it tested, said Richard Chaisson, a Johns Hopkins researcher who is running a separate trial of the drug to determine whether it is effective in treating patients with moderate to severe versions of COVID-19.

There is still a need for robust studies looking at whether it might work in low doses before or after exposure, as well as against mild cases, moderate cases, hospitalized patients and seriously ill ones, he added.

WHO'S KNOCK-ON EFFECTS

The WHO decision to halt its trials last week had knock-on effects across the drug industry and medical profession.

French drugmaker Sanofi temporarily stopped enrolling recruits to its own study and pulled supplies of the drug for treatment. The UK COPCOV trial, aimed at establishing if hydroxychloroquine can prevent healthcare workers from contracting COVID-19, hit pause just a week after its launch.

Those studies are yet to resume.

Several European countries also have stopped using the drug for treating some COVID-19 patients.

Some trials have, however, continued despite the WHO's move.

Novartis has not changed course with its study and the UK Recovery trial paused only briefly before moving ahead after safety checks. It is still enrolling patients and has signed up 4,500 recruits so far - 1,500 patients who are on the drug and around 3,000 who aren't.

In short, the jury's still out on hydroxychloroquine for COVID-19, according to Landray at Recovery.

"People can quote data, people can quote experts, but there is continuing huge uncertainty," he said.

(Additional reporting by Michael Erman in New York; Writing by Josephine Mason and Peter Henderson; Editing by Pravin Char and Leslie Adler)