It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Sunday, May 24, 2020
Artificial eye comes closer to human eye capabilities
by Bob Yirka , Tech Xplore
Biomimetic Eye Sees into Future (artist's impression). Credit: Created by Yaying Xu, (c) Fantastic Color Animation Technology Co.
A team of researchers at The Hong Kong University of Science and Technology, the University of California, Berkeley and Lawrence Berkeley National Laboratory has built an artificial eye with capabilities that come close to those of the human eye. In their paper published in the journal Nature, the group describes developing the eye and how well it compares to its human counterpart. Hongrui Jiang with the University of Wisconsin has published a News and Views piece outlining the work by the team in the same journal issue.
Science fiction television shows and movies have depicted robots with vision equal to or surpassing that of humans, along with bionic eyes implanted into people. Unfortunately, real science has not been able to keep pace with such devices—creating visual devices with a spherical shape and a hemispherical retina has proven to be quite challenging. In this new effort, the researchers have built an artificial eye that comes closer—it is modeled on the human eye, including the shape of its parts.
The artificial eye is made with an aluminum-lined tungsten shell that serves as a round casing. It has an iris and lens in front and a retina in the back. The casing is filled with an ionic liquid. What is groundbreaking though, is the retina. It has a base made of aluminum oxide dotted with pores—each of which hosts a photosensor. In the back of the retina are thin flexible wires made of a eutectic gallium–indium alloy that has been sealed using soft rubber tubes. The retina is held in place by a polymeric socket that allows for electrical contact between perovskite nanowires and the liquid-metal wires at the back. The nanowires are banded together and connect to a computer that processes light information coming from the retina.
The artificial eye is able to detect a range of light intensities that are close to that of the human eye. And its light sensitivity is also very near that of the human eye—it also responds to changes in light intensity faster than the human eye. It's capable of producing very high-resolution imagery, at least in theory. In the current model, the nanowires are banded together into groups of three or four wires, leaving the eyeball with a resolution of just 10x10 pixels, far short of the human eye. This is because of the size of the wires compared to the sensors—for the artificial eye to approach the resolution of the human eye, it will be necessary to connect millions of very tiny wires to the retina.Combining natural and artificial vision to treat a common form of blindness
More information:Leilei Gu et al. A biomimetic eye with a hemispherical perovskite nanowire array retina,Nature(2020).DOI: 10.1038/s41586-020-2285-x
The game that ate the world: 40 facts on Pac-Man's 40th birthday
The iconic maze chase has been played billions of times, created one of the 80s’ strangest sex symbols, stupefied Martin Amis – and is now enshrined in a leading art museum
Ghosts in the machine … Pac-Man. Photograph: Namco
It was on this day in 1980 that one of gaming’s most iconic characters made his debut. To celebrate, here are 40 facts about the ravenous yellow circle and his proud, pill-popping legacy …
1. Pac-Man was created by game designer Toru Iwatani – he was just 24 at the time. The idea for the character came to him when he removed a slice from a pizza.
2. He was also partly inspired by the onomatopoeic phrase paku paku meaning “chomp chomp” and the kanji symbol for the word taberu meaning “to eat”.
3. In 2010, Iwatani told Wired that Pac-Man particularly targeted female players. “When you think about things women like, you think about fashion, or fortune-telling, or food or dating boyfriends. So I decided to theme the game around ‘eating’.” There is absolutely nothing problematic about this statement …
4. To make the game more kawaii (“cute”), Iwatani designed the ghosts in bright colours and gave them large doe-eyes.
5. The ghosts are called Blinky, Pinky, Inky and Clyde and they each have their own personalities based on AI routines. Blinky constantly chases Pac-Man, Pinky attempts to ambush him, Inky is randomised depending on Pac-Man’s position and Clyde will get close to the player then attempt to flee to the bottom left corner, potentially cutting off escape routes.
Arcade adventure … Pac-Man. Photograph: Adam Berry/Getty Images
6. The idea of eating a power pill to give Pac-Man super strength came partly from the cartoon Popeye and his love of spinach, and partly from the Japanese concept of kokoro (“spirit”) or life force. It’s considered one of the first examples of a “power up” in video game history.
7. Pac-Man manufacturer Namco installed the first machine in a movie theatre in Shibuya, Tokyo, on 22 May 1980.
8. The game was only a moderate success until its blockbusting US launch the following October.
9. It was originally called Puck Man, but the US distributor Midway was worried that the word Puck could easily be modified by mischievous vandals into something ruder. Hence, Pac-Man.
10. The game features short animated sequences between levels, showing Pac-Man being chased by the ghosts. This was one of the first examples of a non-interactive video game “cutscene”.
11. Martin Amis was a fan of the game and in his 1982 book Invasion of the Space Invaders claimed to have spent weeks in “a Pac-Man-fed stupor […] unwilling and unable to think about anything else”.
12. Within a year of Pac-Man’s launch, 100,000 units had been sold and 250m games were being played every week. Pac-Man became gaming’s first marketable mascot, with licensed merchandise including lunchboxes, joke books, T-shirts, board games, pyjamas and, for the romantic gamer, Valentine cards.
Inspired by pizza … Toru Iwatani, creator of Pac-Man. Photograph: Elvis Gonzalez/EPA
13. A strategy guide to the game, Mastering Pac-Man by professional blackjack player Ken Uston, sold more than 1m copies.
14. With its simplified maze and blocky visuals, the Atari 2600 version of Pac-Man is widely considered one of the worst arcade-to-home console conversions of all time. Although it sold 7m copies, the game was so wretched it has been widely blamed for the 1983 video game crash, alongside the similarly poor title, ET.
15. Japanese toy manufacturer Tomy made a famously beautiful, handheld Pac-Man game in the shape of an enormous yellow blob with an LCD display. This advert for the device is quite a rush.
16. The tribute song Pac-Man Fever by artists Jerry Buckner and Gary Garcia reached number nine in the US charts in March 1982. An album of video-game-inspired songs followed. It was not good.
17. The game’s distinctive electronic music and sound effects were also an inspiration to early hip-hop pioneers. Notable examples include Jonzun Crew’s Pack Jam and Newcleus’s Jam on Revenge (The Wikki-Wikki Song).
18. The game gave us this Marcus Brigstocke joke: “If Pac-Man had affected us as kids, we’d all be running around in dark rooms, munching pills and listening to repetitive electronic music.”
19. In 1981, Japanese manufacturer Shoei released a terrible “erotic” version of Pac-Man called Streaking. It was later heavily featured in the movie Joysticks, which belonged to the 1980s teen sex comedy genre popularised by Porky’s. Here is the movie trailer. Please don’t watch it.
20. The movie also featured preview footage of Super Pac-Man, Namco’s official sequel to the original game.
21. In a 1982 episode of the sitcom Taxi, Louie (Danny DeVito) installs a Pac-Man cabinet in the garage and Jim (Christopher Lloyd) becomes addicted to the game. The scene is effectively a how-to guide and an advert for Pac-Man rolled into one.
22. Pac-Man was a major element in the appalling Adam Sandler comedy Pixels, with Toru Iwatani getting a cameo as an arcade repairman. But let’s just forget about that, shall we?
23. In 1999, Billy Mitchell became the first person to obtain a perfect Pac-Man score of 3,333,360, eating every dot, power pill, ghost and bonus on every level without losing a single life. However, Mitchell was later accused of cheating by video game records supervisor Twin Galaxies. The record was equalled by David Race in 2012.
24. It is impossible to score higher than that because of a bug in the game that turns the screen to gibberish on the 256th screen.
25. The success of Pac-Man inspired US distributor Bally Midway to create a series of mostly identical sequels: Ms Pac-Man, Pac-Man Plus, Jr Pac-Man, Baby Pac-Man (which added a mini pinball table under the monitor) and Professor Pac-Man.
26. Professor Pac-Man was a quiz game depicting Pac-Man in a mortar board and glasses. It was not a success.
27. In 1982, Hanna-Barbera produced a Pac-Man cartoon series. It features Pac-Man, Ms Pac-Man, their child Pac-Baby and their cat Sour Puss as they attempt to elude the evil Mezmaron who is obsessed with power pills. The intro sequence is a work of hallucinogenic brilliance.
28. In his book Trigger Happy, writer Steven Poole suggested Pac-Man was a precursor to survivor horror games such as Resident Evil and Silent Hill due to its confined, maze-like map, supernatural enemies and emphasis on evasion.
29. In corporate parlance, “the Pac-Man defence” is a strategy in which a company targeted for a hostile takeover attempts to turn the tables and purchase the acquirer.
30. Ms Pac-Man is widely considered a better game than Pac-Man, due to the more varied maze design and improved ghost AI.
31. However, it is most remembered for the image on the side of the game cabinet, which depicts Ms Pac-Man with high heels, red lipstick and fluttering eyelashes, making her the decade’s most bizarre and confusing sex symbol. And, bearing in mind we’re talking about the 80s, that’s really saying something.
32. In the Friends episode The One Where Joey Dates Rachel, Phoebe gives Chandler and Monica a pristine Ms Pac-Man cabinet as a late wedding present – a generous gift as it would have cost about $2,500.
33. Namco has regularly attempted to update and expand the Pac-Man concept. Sometimes this has worked (scrolling platformers Pac-Land and Pac in Time, and the isometrically viewed Pac-Mania); sometimes it really hasn’t (risible party game Pac-Man Fever and mystifying off-road driving sim Pac-Man World Rally).
34. Pac-Man has also appeared as a playable guest character in many other games, including Everybody’s Golf, Mario Kart Arcade GP and Street Fighter X Tekken. He stars as the world’s cutest racing car in Ridge Racer Type 4.
35. Swiss tech company ClearSpace is developing a satellite capable of orbiting Earth and gobbling up space junk. The project leader nicknamed it “the Pac-Man system”.
36. In 2004, New York University students created a real-world version of Pac-Man entitled Pac-Manhattan, in which a player dressed as Pac-Man had to run around the city avoiding students dressed as ghosts. The game used mobile phone GPS signals to track their positions.
37. French street artist Invader has created several mosaic works featuring the Pac-Man character and ghosts, notably in Paris and Bilbao.
38. For his spring/summer 2009 collection, fashion designer Giles Deacon dressed the models in gigantic Pac-Man helmets and had dots painted along the runway.
39. In 2012, Pac-Man was one of 14 video games brought into the collection at MoMA in New York and displayed in its architecture and design gallery.
40. Toru Iwatani returned to Pac-Man in 2007, co-designing the brilliant Xbox title Pac-Man Championship Edition, which adds a time limit and an endlessly transforming maze layout. It was a fitting end to his Pac-Man odyssey.
Pac-Man reinvented by Nvidia AI on its 40th birthday
by Peter Grad , Tech Xplore
Forty years ago Friday the most popular video game of all time was released.
Pac-Man was designed by a nine-person team at the Japanese company Namco.
Today, the game has been born again, this time the result of an artificial intelligence model undertaken by Nvidia Research. And it was accomplished without an underlying game engine, the standard procedure for designing such games, but rather by training a neural network by having it "watch" 50,000 hours of the original game.
GameGAN is considered the first neural network model employing generative adversarial networks. In this type of system, one network learns to recognize patterns within images and create its own distinctive images in a fashion similar to the origjnals. An adversarial computer is tasked with distinguishing between real mages and the manufactured ones.
In this instance, Nvidia researchers did no game programming, but rather relied on GameGAN to examine Pac-Man libraries and then construct its own scenarios of the game. In other words, with artificial intelligence, a realistic copy of the game was created even though there is no code mapping the game's fundamental rules.
"This is the first research to emulate a game engine using GAN-based neural networks," according to Seung-Wook Kim, the lead Nvidia researcher on the project. "We wanted to see whether the AI could learn the rules of an environment just by looking at the screenplay of an agent moving through the game. And it did.
Researchers are pleased with the results of the regenerated Pac-Man, but see applications beyond gaming in the future. The system can be applied to robotics where machines will work side by side with humans in cooperative manufacturing ventures, for instance. Self-driving cars are another field ripe for research.
"We could eventually have an AI that can learn to mimic the rules of driving, the laws of physics, just by watching videos and seeing agents take actions in an environment," said Sanja Fidler, director of the Nvidia research lab in Toronto. "GameGAN is the first step toward that."
For Rev Lebaredian, vice president of simulation technology at Nvidia, it all comes down to simple observation.
"It learns all of these things just by watching… similar to how a human programmer can watch many episodes of Pac-Man on YouTube and infer what the rules of the games are and reconstruct them."
Nvidia says it will make the game available on its online AI Playground later this year.
Six fun facts about Pac-Man:
— Pac-Man is often cited as the most popular video game of all time. According to the Davie Brown Index, is has the highest brand awareness in its class of all video game characters.
— According to Money magazine, the Pac-Man franchise has sold an estimated 44 million games since May 22, 1980. And as of 2016, it generated more than $14 billion in revenue.
— The first person credited with having won a perfect score of 3,333,360—earning the maximum possible score in the first 255 levels by eating all dots, energizers, fruits and enemies, without losing a life, and using extra lives to score the maximum on level 256—was Billy Mitchell in 1999. As of 2019, seven other players have attained that level.
— Pac-Man is part of the Smithsonian Institution's collection and is in the New York Museum of Modern Art display.
— Guinness World Records lists Pac-Man for eight records, including "Most Successful Coin-Operated Game."
— The game, created in Japan, was originally named Puck Man, but that was changed to Pac-Man for release in the English-speaking world because developers feared mischievous teenagers would alter the nameplates to spell out a distasteful word. More information:blogs.nvidia.com/blog/2020/05/ … 2#cid=_so-yout_en-us
First commercial space taxi a pit stop on Musk's Mars quest
by Seth Borenstein
In this Tuesday, Sept. 27, 2016 file photo, SpaceX founder Elon Musk speaks during the 67th International Astronautical Congress in Guadalajara, Mexico. Starting with the dream of growing a rose on Mars, Musk's vision morphed into a shake-up of the old space industry, and a fleet of new private rockets. In 2020, those rockets are scheduled to launch NASA astronauts from Florida to the International Space Station—the first time a for-profit company will carry astronauts into the cosmos. (AP Photo/Refugio Ruiz)
It all started with the dream of growing a rose on Mars.
That vision, Elon Musk's vision, morphed into a shake-up of the old space industry, and a fleet of new private rockets. Now, those rockets will launch NASA astronauts from Florida to the International Space Station—the first time a for-profit company will carry astronauts into the cosmos.
It's a milestone in the effort to commercialize space. But for Musk's company, SpaceX, it's also the latest milestone in a wild ride that began with epic failures and the threat of bankruptcy.
If the company's eccentric founder and CEO has his way, this is just the beginning: He's planning to build a city on the red planet, and live there.
"What I really want to achieve here is to make Mars seem possible, make it seem as though it's something that we can do in our lifetimes and that you can go," Musk told a cheering congress of space professionals in Mexico in 2016.
Musk "is a revolutionary change" in the space world, says Harvard University astrophysicist Jonathan McDowell, whose Jonathan's Space Report has tracked launches and failures for decades.
In this Tuesday, Feb. 6, 2018 file photo, a Falcon 9 SpaceX heavy rocket lifts off from pad 39A at the Kennedy Space Center in Cape Canaveral, Fla. The Falcon Heavy, has three first-stage boosters, strapped together with 27 engines in all. (AP Photo/John Raoux)
Ex-astronaut and former Commercial Spaceflight Federation chief Michael Lopez-Alegria says, "I think history will look back at him like a da Vinci figure."
Musk has become best known for Tesla, his audacious effort to build an electric vehicle company. But SpaceX predates it.
At 30, Musk was already wildly rich from selling his internet financial company PayPal and its predecessor Zip2. He arranged a series of lunches in Silicon Valley in 2001 with G. Scott Hubbard, who had been NASA's Mars czar and was then running the agency's Ames Research Center.
Musk wanted to somehow grow a rose on the red planet, show it to the world and inspire school children, recalls Hubbard.
"His real focus was having life on Mars," says Hubbard, a Stanford University professor who now chairs SpaceX's crew safety advisory panel.
In this Thursday, April 11, 2019 file photo, SpaceX lands two of the first-stage boosters side by side, eight minutes after liftoff at the Kennedy Space Center in Cape Canaveral, Fla. (AP Photo/John Raoux)
The big problem, Hubbard told him, was building a rocket affordable enough to go to Mars. Less than a year later Space Exploration Technologies, called SpaceX, was born.
There are many space companies and like all of them, SpaceX is designed for profit. But what's different is that behind that profit motive is a goal, which is simply to "Get Elon to Mars," McDowell says. "By having that longer-term vision, that's pushed them to be more ambitious and really changed things."
Everyone at SpaceX, from senior vice presidents to the barista who offers its in-house cappuccinos and FroYo, "will tell you they are working to make humans multi-planetary," says former SpaceX Director of Space Operations Garrett Reisman, an ex-astronaut now at the University of Southern California.
Musk founded the company just before NASA ramped up the notion of commercial space.
In this Tuesday, Aug. 27, 2019 file photo, SpaceX tests their StarHopper, successfully hovering 500 feet above the launch site and safely landing at the company's facility in Brownsville, Texas. (Miguel Roberts/The Brownsville Herald via AP)
Traditionally, private firms built things or provided services for NASA, which remained the boss and owned the equipment. The idea of bigger roles for private companies has been around for more than 50 years, but the market and technology weren't yet right.
NASA's two deadly space shuttle accidents—Challenger in 1986 and Columbia in 2003—were pivotal, says W. Henry Lambright, a professor of public policy at Syracuse University.
When Columbia disintegrated, NASA had to contemplate a post-space shuttle world. That's where private companies came in, Lambright says.
After Columbia, the agency focused on returning astronauts to the moon, but still had to get cargo and astronauts to the space station, says Sean O'Keefe, who was NASA's administrator at the time. A 2005 pilot project helped private companies develop ships to bring cargo to the station.
In this March 4, 2019 photo made available by NASA, the uncrewed SpaceX Crew Dragon spacecraft, with its nose cone open to expose the docking mechanism, approaches the International Space Station's Harmony module. It was the first Commercial Crew vehicle to visit the ISS. (NASA via AP)
SpaceX got some of that initial funding. The company's first three launches failed. The company could have just as easily failed too, but NASA stuck by SpaceX and it started to pay off, Lambright says.
"You can't explain SpaceX without really understanding how NASA really kind of nurtured it in the early days," Lambright says. "In a way, SpaceX is kind of a child of NASA."
Since 2010, NASA has spent $6 billion to help private companies get people into orbit, with SpaceX and Boeing the biggest recipients, says Phil McAlister, NASA's commercial spaceflight director.
NASA plans to spend another $2.5 billion to purchase 48 astronaut seats to the space station in 12 different flights, he says. At a little more than $50 million a ride, it's much cheaper than what NASA has paid Russia for flights to the station.
In this Thursday, May 29, 2014 file photo, Elon Musk, CEO and CTO of SpaceX, walks down the steps during the introduction of the SpaceX Dragon V2 spaceship at the headquarters in Hawthorne, Calif., designed to ferry astronauts to low-Earth orbit. (AP Photo/Jae C. Hong)
Starting from scratch has given SpaceX an advantage over older firms and NASA that are stuck using legacy technology and infrastructure, O'Keefe says.
And SpaceX tries to build everything itself, giving the firm more control, Reisman says. The company saves money by reusing rockets, and it has customers aside from NASA.
The California company now has 6,000 employees. Its workers are young, highly caffeinated and put in 60- to 90-hour weeks, Hubbard and Reisman say. They also embrace risk more than their NASA counterparts.
Decisions that can take a year at NASA can be made in one or two meetings at SpaceX, says Reisman, who still advises the firm.
In 2010, a Falcon 9 rocket on the launch pad had a cracked nozzle extension on an engine. Normally that would mean rolling the rocket off the pad and a fix that would delay launch more than a month.
In this Monday, Sept. 17, 2018 file photo, Japanese billionaire Yusaku Maezawa speaks after SpaceX founder and chief executive Elon Musk announced him as the person who would be the first private passenger on a trip around the moon in Hawthorne, Calif. (AP Photo/Chris Carlson) This artist's rendering made available by Elon Musk on Friday, Sept. 29, 2017, depicts a SpaceX rocket design on the Earth's moon. (SpaceX via AP, File)
In this Saturday, Sep. 28, 2019 file photo, SpaceX's Starship Mk 1 is illuminated against the night sky at the South Texas Ground Control Station in Brownsville, Texas. Starting with the dream of growing a rose on Mars, Elon Musk's vision morphed into a shake-up of the old space industry, and a fleet of new private rockets. Now, those rockets will launch NASA astronauts from Florida to the International Space Station—the first time a for-profit company will carry astronauts into the cosmos. (Miguel Roberts/The Brownsville Herald via AP)
In this Monday, Sept. 17, 2018 file photo, Japanese billionaire Yusaku Maezawa speaks after SpaceX founder and chief executive Elon Musk announced him as the person who would be the first private passenger on a trip around the moon in Hawthorne, Calif. (AP Photo/Chris Carlson)
This artist's rendering made available by Elon Musk on Friday, Sept. 29, 2017, depicts a SpaceX rocket design on the Earth's moon. (SpaceX via AP, File)
But with NASA's permission, SpaceX engineer Florence Li was hoisted into the rocket nozzle with a crane and harness. Then, using what were essentially garden shears, she "cut the thing, we launched the next day and it worked," Reisman says.
Musk is SpaceX's public and unconventional face—smoking marijuana on a popular podcast, feuding with local officials about opening his Tesla plant during the pandemic, naming his newborn child "X Æ A-12." But insiders say aerospace industry veteran Gwynne Shotwell, the president and chief operating officer, is also key to the company's success.
"The SpaceX way is actually a combination of Musk's imagination and creativity and drive and Shotwell's sound management and responsible engineering," McDowell says.
But it all comes back to Musk's dream. Former NASA chief O'Keefe says Musk has his eccentricities, huge doses of self-confidence and persistence, and that last part is key: "You have the capacity to get through a setback and look ... toward where you're trying to go."
Saltmarshes about 30 miles (50 km) southeast of New Orleans are vulnerable to drowning. Credit: Torbjörn Törnqvist
Given the present-day rate of global sea-level rise, remaining marshes in the Mississippi Delta are likely to drown, according to a new Tulane University study.
A key finding of the study, published in Science Advances, is that coastal marshes experience tipping points, where a small increase in the rate of sea-level rise leads to widespread submergence.
The loss of 2,000 square miles (5,000 km2) of wetlands in coastal Louisiana over the past century is well documented, but it has been more challenging to predict the fate of the remaining 6,000 square miles (15,000 km2) of marshland.
The study used hundreds of sediment cores collected since the early 1990s to examine how marshes responded to a range of rates of sea-level rise during the past 8,500 years.
"Previous investigations have suggested that marshes can keep up with rates of sea-level rise as high as half an inch per year (10 mm/yr), but those studies were based on observations over very short time windows, typically a few decades or less," said Torbjörn Törnqvist, lead author and Vokes Geology Professor in the Tulane Department of Earth and Environmental Sciences.
"We have taken a much longer view by examining marsh response more than 7,000 years ago, when global rates of sea-level rise were very rapid but within the range of what is expected later this century."
The researchers found that in the Mississippi Delta most marshes drown in a few centuries once the rate of sea-level rise exceeds about one-tenth of an inch per year (3 mm/yr). When the rate exceeds a quarter of an inch per year (7.5 mm/yr), drowning occurs in about half a century.
"The scary thing is that the present-day rate of global sea-level rise, due to climate change, has already exceeded the initial tipping point for marsh drowning," Törnqvist said. "And as things stand right now, the rate of sea-level rise will continue to accelerate and put us on track for marshes to disappear even faster in the future."
While these findings indicate that the loss of remaining marshes in coastal Louisiana is probably inevitable, there are still meaningful actions that can be taken to prevent the worst possible outcomes. The most important one, Törnqvist said, is to drastically curb greenhouse gas emissions to prevent sea-level rise from ramping up to rates where marshes will drown within a matter of decades.
The other one is to implement major river diversions as quickly as possible, so at least small portions of the Mississippi Delta can survive for a longer time. However, the window of opportunity for these actions to be effective is rapidly closing, he said.Louisiana wetlands struggling with sea-level rise four times the global average
More information:Tipping points of Mississippi Delta marshes due to accelerated sea-level rise,Science Advances(2020).DOI: 10.1126/sciadv.aaz551
King penguins in a colony in Antarctica emit so much nitrous oxide—also known as laughing gas—from their feces that a team of researchers studying them went "cuckoo" from the fumes.
The scientists, from the University of Copenhagen in Denmark, were investigating the effect of glacier retreat and penguin activity on greenhouse gas emissions. To do this, they went on a research trip to South Georgia, an island in the southern Atlantic ocean, where the world's largest colony of king penguins live—around 150,000 breeding pairs, the team notes.
Penguin feces, known as guano, is known to release huge amounts of nitrous oxide (N2O). This is a potent greenhouse gas, with a warming effect around 300 times that of carbon dioxide (CO2). The N2O is created when the penguins eat fish and krill that have absorbed large amounts of nitrogen via phytoplankton. Nitrogen is released from the guano, and the soil it lands on converts it into N2O.
As well as being a greenhouse gas, N2O is also used as a sedative by dentists, and some people use it recreationally because of its psychoactive effects. These include making the user feel euphoric and relaxed, and causing fits of laughter.
"After nosing about in guano for several hours, one goes completely cuckoo," lead researcher Bo Elberling said in a statement. "One begins to feel ill and get a headache. The small nitrous oxide cylinders that you see lying in and floating around Copenhagen are no match for this heavy dose, which results from a combination of nitrous oxide with hydrogen sulphide and other gases."
As a greenhouse gas, most N2O comes from agricultural soil management. The U.S. Environmental Protection Agency says N2O accounts for 6.5 percent of all America's man-made emissions. Elberling said N2O emissions at the colony are around 100 times higher than a newly fertilized field in Denmark. "It is truly intense," he said.
Findings from the research trip have been published in the journal Science of the Total Environment. In it, the team say that as glaciers retreat, more land will be exposed and this is likely to alter the level of greenhouse gasses emitted from these regions.
"Penguins have been considered to be an ideal 'bio-indicator' of ecosystem and environmental changes, as changes in populations and colonies reflect direct and indirect ecological responses to climatic changes," they wrote. "Changes in penguin colonies, penguin activity and the associated addition of guano are known to significantly influence terrestrial soil and ecosystem processes and thereby can turn soils into [greenhouse gas] emission hotspots."
The scientists looked at changes to N2O, CO2 and methane (CH4) by analyzing soil samples taken from different areas of the island. These were incubated and assessed for greenhouse gas production and consumption. Findings showed soil was heavily influenced by penguin activity. In areas penguins frequent, there was increased CO2 and N2O production, as well as a fall in CH4 consumption. When they applied penguin guano to soil in controlled experiments, they also found a "significant increase" in CO2 and N2O, and a drop in CH4 consumption.
This, they suggest, shows the increase in nutrients that penguin guano provides leads to more greenhouse gas production. If penguins populations expand as glaciers retreat and more land becomes ice-free, there could be an increase in greenhouse gas emissions, they conclude.
"While nitrous oxide emissions in this case are not enough to impact Earth's overall energy budget, our findings contribute to new knowledge about how penguin colonies affect the environment around them, which is interesting because colonies are generally becoming more and more widespread," Elberling said in a statement.
Stock photo of a king penguin. Researchers find penguin guano increases levels of CO2 and N2O.ISTOCK
This artist's rendering made available 
