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Sharks are abandoning stressed coral reefs in warming oceans, study finds

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Sharks are abandoning stressed coral reefs in warming oceans, study finds


reef shark
Credit: Pixabay/CC0 Public Domain

Gray reef sharks are having to abandon the coral reefs they call home in the face of warming oceans, new research finds.

Scientists, using a combination of satellite remote sensing and a network of acoustic receivers on the seabed, have discovered that sharks are deserting coral reefs at times of environmental stress, such as high temperatures that can lead to coral bleaching events.

The effects on these sharks, normally strongly attached to particular areas of shallow reef habitats, include lower residency, more widespread and frequent movements to different areas and longer periods of absence entirely. Worryingly, these effects persisted for extended periods of up to 16 months following extreme stress periods such as the 2015-2016 El Niño event, which caused substantial bleaching in the study region.

The research is published in the journal Communications Biology.

As climate change is predicted to cause bleaching events annually by 2043, this behavioral change is “concerning,” say the scientists.

An international research team, led by marine scientists at Lancaster University and ZSL, attached acoustic trackers to more than 120 sharks and installed receivers around coral atolls to monitor shark movements at reefs in the Indian Ocean between 2013 to 2020.

They recorded more than 714,000 acoustic detections and, in collaboration with Earth Observation scientists at King’s College London, combined these with satellite data recording different metrics of reef environmental stress.

Scientists behind the study say this has important consequences for both the sharks and the reefs.

“These results provide some of the first evidence of how reef change in response to environmental stress, something that is becoming both more extreme and more frequent, is affecting the movement of sharks,” said Dr. David Jacoby of Lancaster University and principal investigator on the research project. “Gray reef sharks are a common, resident predator on the reefs of the Indo-Pacific, venturing away from the reef to feed, but many are having to decide whether to escape the stressed reefs.

“Faced with a tradeoff, sharks must decide whether to leave the relative safety of the reef and expend greater energy to remain cool or stay on a reef in suboptimal conditions but conserve energy. We think many are choosing to move into offshore, deeper and cooler waters, which is concerning. Many reefs around the globe have already seen significant declines in sharks due to exploitation and this finding has the potential to exacerbate these trends.”

Although the study didn’t examine the precise mechanisms linking reef stress to shark movement and residency, stress on coral reefs is often closely linked to sea surface temperatures.

“Sharks are ectotherms—cold-blooded animals whose body temperature is regulated by their external environment,” said Dr. Michael Williamson from ZSL’s Institute of Zoology, and lead author of the paper. “Reef sharks in other regions exhibit behavioral thermoregulation to avoid physiological damage from adverse water temperatures, and this is one of the potential drivers of the findings in this study.”

Importantly, sharks moving away could impact the fragile balance in reef ecosystems.

“As large predators, gray reef sharks play a very important role in coral reef ecosystems,” said Dr. Williamson. “They maintain a delicately balanced food web on the reef and they also cycle nutrients onto coral reefs from deeper waters where they often feed. A loss of sharks, and the nutrients they bring, could affect the resilience of reefs during periods of high environmental stress.”

Dr. Jacoby said, “As climate change brings increasing uncertainty and more and more frequent extreme stress events, the important ecological role these predators play on coral reefs is likely to change, as they spend more time away from the reefs they are attached to. The implications of this are not yet fully understood, but given the complex balance of species and trophic interactions that occur on coral reefs, there will certainly be substantial changes.”

However, there is also some room for optimism in the study’s findings.

Not all the monitored locations saw a decline in habitat use. In fact, some acoustic receivers at specific locations saw shark residency actually increase. These findings indicate that there could be localized factors influencing shark decisions, and that some reefs are more resilient to stress.

“We now need to find out what exactly is driving decision-making in these animals during periods of stressful conditions,” says Dr. Jacoby.

Although these factors were not included in the study, scientists suggest that different reefs can respond differently when exposed to stress.

“Recent research in the Chagos Archipelago, where we conducted our study, has shown that those reefs that have greater nutrient flows from seabirds have significantly enhanced fish biomass and therefore a higher likelihood to be resilient to multiple stressors,” said Dr. Williamson. “Some of our receivers that were seeing a greater number of sharks residing were also near islands with seabird populations.”

More information:
Michael J. Williamson et al, Environmental stress reduces shark residency to coral reefs, Communications Biology (2024). DOI: 10.1038/s42003-024-06707-3

Citation:
Sharks are abandoning stressed coral reefs in warming oceans, study finds (2024, September 9)
retrieved 9 September 2024
from https://phys.org/news/2024-09-sharks-abandoning-stressed-coral-reefs.html

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New 2D metamaterial enhances satellite communication for 6G networks

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New 2D metamaterial enhances satellite communication for 6G networks


2D metamaterial breakthrough for satellite applications in 6G networks
The unit cell design. Credit: Communications Engineering (2024). DOI: 10.1038/s44172-024-00266-5. https://www.nature.com/articles/s44172-024-00266-5

A new, cheap, easily manufactured device could lead to improved satellite communication, high speed data transmission, and remote sensing, scientists say.

A team of engineers led by researchers from the University of Glasgow have developed an ultrathin 2D surface that harnesses the unique properties of metamaterials to manipulate and convert radio waves across the frequencies most commonly used by satellites.

Metamaterials are structures that have been carefully engineered to imbue them with properties that don’t exist in naturally occurring materials.

The team’s metamaterial, unveiled today in a new paper published in the journal Communications Engineering, could allow future generations of 6G satellites to carry more data, improve their remote sensing ability, and benefit from improved signal quality.

Current communication antennas are designed to transmit and receive electromagnetic waves oriented either vertically or horizontally—a property called linear polarization.

Misalignment between transmitting and receiving antennas can lead to signal degradation, reducing their efficiency. They are also susceptible to atmospheric effects such as rain fading and ionospheric interference, which can distort signals.

The team’s breakthrough 2D metamaterial converts the linearly polarized electromagnetic waves into circular polarization, which could improve the quality of communication between satellites and ground stations. Satellite communication with circular polarization offers enhanced reliability and performance, minimizing signal degradation from polarization mismatch and multipath interference.

Circular polarization is highly resistant to atmospheric effects like rain fading and ionospheric disturbances, ensuring stable connections. It is especially beneficial in mobile applications, as it eliminates the need for precise antenna alignment.

It also doubles channel capacity by using both right-hand and left-hand circular polarizations. This flexibility simplifies antenna design for small satellites, while improving satellite tracking and providing robust communication links in challenging environments, making it ideal for modern satellite systems.

The team’s metamaterial, which is just 0.64mm thick, is made from tiny cells of geometrically patterned copper, which is laid over a commercial circuit board commonly used in high-frequency communications.

The surface of the metamaterial is designed to allow sophisticated reflection and repolarization of electromagnetic waves. In lab tests, the 2D metamaterial surface was illuminated by signals from horn antennas and the reflected electromagnetic wave was captured using a network analyzer, which allowed the team to measure the effectiveness of the device’s conversion between linear and circular polarization. The experimental results showed a close resemblance between simulated and experimental measurements for polarization conversion to circular polarization.

Their tests also showed that the surface is capable of maintaining high performance even when radio signals glance across it at angles of up to 45 degrees—a key consideration for space applications, where perfect alignment between satellites and the surface can be fleeting.

Professor Qammer H. Abbasi, of the University of Glasgow’s James Watt School of Engineering, is the paper’s senior and corresponding author. He said, “Previous developments in metamaterials have provided new ways for electromagnetic waves to be manipulated in devices with small form factors. However, they’ve largely been limited to narrow bands of the spectrum, which has limited their practical applications so far.

“The metamaterial surface we’ve developed works across a wide range of frequencies across the Ku-, K- and Ka-bands, which span 12 GHz to 40Ghz, and are commonly used in satellite applications and remote sensing.

“This kind of 2D metamaterial surface, capable of the complex task of linear to circular polarization, can enable antennae to communicate with each other more effectively in challenging conditions.

“It could help satellites provide better signals for phones, and more stable connections for data transmission. It could also improve satellites’ ability to scan the surface of the Earth, improving our understanding of the effects of climate change or our ability to track wildlife migration.”

Dr. Humayun Zubair Khan was a visiting postdoctoral student at University of Glasgow’s James Watt School of Engineering during the development of the metamaterial surface. Now at the National University of Sciences and Technology in Pakistan, he is the first author on the paper. He said, “This is an exciting development, which outperforms previously-developed technologies by a significant margin.

“Being able to manipulate and convert electromagnetic waves with a single piece of equipment opens up a range of new potential applications across the communications sector, but particularly in the space industry, where lightweight, compact materials are prized to help keep launch payloads down.”

Professor Muhammad Imran leads the University of Glasgow’s Communications, Sensing and Imaging hub, and is a co-author of the paper. He said, “One of the most exciting aspects of the metasurface we’ve developed is that it can be easily mass-produced using conventional printed circuit board manufacturing techniques.

“That means that it can be made easily and affordably, which could help it become widely-adopted in the years to come as a valuable piece of onboard equipment for satellites.”

More information:
Humayun Zubair Khan et al, Multi-band ultrathin reflective metasurface for linear and circular polarization conversion in Ku, K, and Ka bands, Communications Engineering (2024). DOI: 10.1038/s44172-024-00266-5. www.nature.com/articles/s44172-024-00266-5

Citation:
New 2D metamaterial enhances satellite communication for 6G networks (2024, September 9)
retrieved 9 September 2024
from https://techxplore.com/news/2024-09-2d-metamaterial-satellite-communication-6g.html

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Pay-by-weight airfares are an ethical minefield; we asked travelers what they actually think

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Pay-by-weight airfares are an ethical minefield; we asked travelers what they actually think


airline seat
Credit: Pixabay/CC0 Public Domain

Imagine checking in for a flight with your two teenage children. At the counter, you are told that your youngest teenager’s suitcase is two kilograms over the limit. You get slapped with a $75 penalty for their excess luggage.

This penalty feels arbitrary and unfair. The youngest weighs about 45 kg, and their luggage weighs 25 kg, making their total payload on the flight 70 kg.

Their older sibling, on the other hand, weighs 65 kg, and has brought 23 kg of luggage to check in. Their total weight is higher—88 kg—yet they receive no penalty.

Obviously, things aren’t that simple. Charging passengers based on their weight is highly controversial for many reasons. But that hasn’t stopped some airlines experimenting with such policies.

Imagine checking in for your flight only to have the staff tell you to purchase an extra seat as you are a plus-sized passenger. You feel discriminated against because you are using the same service as other passengers and your weight is beyond your control.

But despite the lived experience of many and hot debate in the media, there has not been a formal study into what passengers themselves think about this matter.

Our recently published research examined air passengers’ views on alternative airfare policies to understand whether the public finds them acceptable and what ethical considerations determine their views.

Though we found a range of ethical contradictions, most travelers were guided by self-interest.

A controversial but important topic

The issue of whether airlines should weigh passengers is an ethical minefield with no easy answers.

Despite its sensitivity, the aviation industry can’t ignore passenger weight. Airlines intermittently undertake passenger weight surveys as they need to accurately calculate payload to ensure flight safety and estimate fuel consumption.

The evidence shows passengers are getting heavier. Airlines including the now-defunct Samoa Air and Hawaiian Airlines have taken things one step further and experimented with weighing passengers regularly.

Samoa Air, for example, became the first airline to introduce a “pay-as-you-weigh” policy, where the cost of your ticket was directly proportional to the combined weight of you and your luggage.

In contrast, Canada has now long had a “one person, one fare” policy. It is prohibited and deemed discriminatory to force passengers living with a disability to purchase a second seat for themselves if they require one, including those with functional disabilities due to obesity.

To complicate matters further, the issue of passenger and luggage weight is not only ethical and financial, but also environmental. More weight on an aircraft leads to more jet fuel being burned and more carbon emissions.

About 5% of human-driven climate change can be attributed to aviation, and the industry faces enormous pressure to reduce fuel consumption while it waits for low carbon substitutes to become available.

What do passengers actually think?

To get a better sense of how the public actually feels about this issue, we surveyed 1,012 US travelers of different weights, presenting them with three alternatives:

  • standard policy—currently the most widely used policy with passengers paying a standard price, irrespective of their weight
  • threshold policy—passengers are penalized if they are over a threshold weight
  • unit of body weight policy—passengers pay a personalized price based on their own body weight, per each pound.

The standard policy was the most acceptable for participants of differing weight, although the heavier the passenger, the more they preferred the standard policy. This can be partially explained by status quo bias. Generally, people are likely to choose a familiar answer.

The threshold policy was the least acceptable. This policy was seen to violate established social norms and be generally less fair.

The unit of body weight policy was preferred to the threshold policy, although participants raised concerns about whether it would be accepted by society.

Perhaps unsurprisingly, we found that self-interest played a clear role in determining whether respondents considered a policy acceptable.

Younger, male, financially well-off travelers with lower personal weight generally found the alternative policies more acceptable.

An ethical conflict

Alternative airfare policies that are based on passenger weight bring environmental and ethical concerns into conflict. Obviously, the effect isn’t from any one traveler, in particular, but averages over the entire industry.

Interestingly, respondents that were more concerned about the environment—”ecocentric”—preferred air fare policies that would reduce carbon emissions. This made them more open to the controversial alternatives.

While the threshold policy was clearly rejected by many respondents as discriminatory, environmental concern played a role in the level of acceptance of the unit of body weight policy.

It’s important to apply a critical lens here. These ecocentric travelers were also generally younger and had lower personal weights, so many would benefit from the alternative policies financially.

For policymakers overall, our study suggests that when it comes to controversial ticketing policies, the public is more likely to be swayed by self-interest than anything else.

Provided by
The Conversation


This article is republished from The Conversation under a Creative Commons license. Read the original article.The Conversation

Citation:
Pay-by-weight airfares are an ethical minefield; we asked travelers what they actually think (2024, September 9)
retrieved 9 September 2024
from https://phys.org/news/2024-09-pay-weight-airfares-ethical-minefield.html

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Talks between Boeing and its biggest union are coming down to the wire—and a possible strike

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Talks between Boeing and its biggest union are coming down to the wire—and a possible strike


Talks between Boeing and its biggest union are coming down to the wire - and a possible strike
A Boeing machinist and union member leads cheers during the “stop work meeting” and strike sanction at T-Mobile Park in Seattle, July 17, 2024. Credit: Kevin Clark/The Seattle Times via AP, File

Boeing and its largest union are entering the last week of contract negotiations before a threatened strike by more than 30,000 workers who build the planes that carry millions of airline passengers every year.

A walkout would add to the headwinds facing Boeing, which is hurtling toward a sixth straight money-losing year and just hired a new CEO to turn things around.

The regional branch of the International Association of Machinists and Aerospace Workers says the two sides are far apart on wages, health care and job security. The union of started out seeking pay raises of more than 40% over three years, although “that’s probably not where we’re going to end up,” IAM District 751 President Jon Holden said last week.

The union has scheduled a two-part election for Thursday, with voting at more than a half-dozen locations in Washington state and one in Southern California. Workers will vote on Boeing’s last contract offer and whether to authorize a strike if the offer is rejected. A walkout could begin by Friday morning.

A straw vote in July to gauge support for a strike passed with 99.99% support, according to the union.

“What we are asking for is reasonable,” Holden said in an interview. “We need to get more wages to address the very low increases over the last 10 years, massive inflation, massive cost-shift on health care. We are trying to reach an agreement, but (union members) are ready to take action if we don’t get there.”

Holden said the union has a strike fund in the millions and isn’t afraid to tap it.

Boeing declined to make an executive available to discuss the labor negotiations. A spokesperson provided a one-sentence statement.

“We’re confident we can reach a deal that balances the needs of our employees and the business realities we face as a company,” the statement said.

Boeing’s new chief executive, Kelly Ortberg, has tried to take a conciliatory posture toward labor. He is working in Seattle, to be near the factories where the company builds most of its commercial airplanes, instead of at headquarters in Arlington, Virginia. He walked the floor of the 737 Max plant during his first day on the job.

“He understands that they are basically contentious relationships with the union, and he wants to make those relationships better,” TD Cowen aerospace analyst Cai von Rumohr said.

Ortberg already has a long to-do list. The new CEO will try to fix Boeing’s aircraft-manufacturing process, gain regulatory approval for the long-delayed 777X jumbo jet, limit damage from over-budget government contracts, pay down $45 billion in net debt, and absorb Spirit AeroSystems, the money-losing key supplier that Boeing just bought for $4.7 billion.

Talks between Boeing and its biggest union are coming down to the wire - and a possible strike
Boeing 737 MAX airplanes are shown on the assembly line during a media tour at the Boeing facility in Renton, Wash., June 25, 2024. Credit: Jennifer Buchanan/The Seattle Times via AP, Pool, File

Ortberg’s toughest job will be restoring Boeing’s reputation for quality, which was crushed after two 737 Max jets crashed less than five months apart in 2018 and 2019, killing 346 people, and took another big hit when a door plug blew off a Max during an Alaska Airlines flight in January.

Unlike strikes at airlines, which are very rare, a walkout at Boeing would not have an immediate effect on consumers. It would not result in any canceled flights. It would, however, shut down production and leave Boeing with no jets to deliver to the airlines that ordered them.

“During a strike, they don’t work on planes, they don’t deliver planes,” von Rumohr said. Aircraft makers typically get about 60% of the purchase price on delivery, “so not delivering planes has a massive impact on your cash in-flow, and your costs probably continue on.”

An eight-week strike in 2008, the longest at Boeing since a 10-week walkout in 1995, cost the company about $100 million a day in deferred revenue.

Meeting the union’s wage demand would cost Boeing $1.5 billion in cash, which is “a small price to pay versus a strike,” Jefferies aerospace analyst Sheila Kahyaoglu said. In a note to clients, she estimated a strike would cost the company about $3 billion, a calculation based on the impact of the 2008 strike plus inflation and current airplane-production rates.

Boeing is in far worse financial shape than it was in 2008. The company has lost $27 billion since the start of 2019, around the time that its best-selling plane, the 737 Max, was grounded worldwide after the crashes in Indonesia and Ethiopia. Revenue is down, debt is up.

Boeing’s greatest strength is that is remains one of the world’s two leading manufacturers of airline jets, forming a duopoly with Europe’s Airbus. Boeing has a huge backlog of orders, which it values at more than $500 billion.

The company’s defense and space business is a major government contractor, although that business too is struggling. Its most recent setback was NASA’s decision to use SpaceX instead of Boeing’s Starliner capsule to bring two astronauts home from the international space station.

Job security is emerging as a key issue in the current negotiations. The union is still seething over the loss of work on the 787 Dreamliner, a large, two-aisle jetliner that is assembled by nonunion Boeing workers in South Carolina. The IAM wants a guarantee its members will keep the work they have and that the union will represent the workers who build Boeing’s next airliner.

That plane isn’t even on the drawing board yet, and production could be a decade or more away. It is vital to IAM, however, because one-third of the union’s members at Boeing—more than 10,000 people—work on the 737 Max, which the new plane would replace.

The union president said Boeing has been in “free fall” for more than a year, and he acknowledged the company faces huge and costly challenges. Despite all that, he said, the union is in good position to win a strong contract.

“All employers are searching for skilled labor, and we have it,” Holden said. “This company has a massive backlog of over 5,000 airplanes to build and deliver, so we are in high demand right now. That’s our leverage.”

© 2024 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.

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Talks between Boeing and its biggest union are coming down to the wire—and a possible strike (2024, September 9)
retrieved 9 September 2024
from https://techxplore.com/news/2024-09-boeing-biggest-union-wire.html

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A blockbuster Chinese video game sparks debate on sexism in the nation’s gaming industry

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A blockbuster Chinese video game sparks debate on sexism in the nation’s gaming industry


A blockbuster Chinese video game sparks debate on sexism in the nation’s gaming industry
A man holds up an umbrella against the rain as he walks past an ad promoting the latest blockbuster new Chinese video game “Black Myth: Wukong” in Beijing, Friday, Aug. 23, 2024. Credit: AP Photo/Ng Han Guan

A blockbuster new Chinese video game hailed as a milestone for the country’s gaming industry has put an unexpected spotlight on longstanding claims of rampant sexism in China’s male-dominated gaming culture.

While some gamers are basking in the runaway success of the action-adventure title “Black Myth: Wukong,” others are voicing their complaints about sexism in Chinese gaming and lodging allegations against the game’s Shenzhen-based developer, Game Science, that it posted offensive messages online.

Critics posted screenshots of the messages on Chinese social media platform Weibo, with one compilation receiving over 400,000 likes. One of the posts that critics say came from founder Feng Ji uses descriptions of oral sex as a metaphor for the positive responses about the game’s promotional video. Other examples include lewd recruiting posters.

AP was not able to independently verify the screenshots, though gamers interviewed reported seeing the posts. Game Science did not respond to an email seeking comment and hasn’t publicly commented on the controversy.

The criticism reflects simmering anger among Chinese women in the industry who say they have long been targeted by misogynistic remarks and behavior.

Gender inequality is a global problem in the heavily male-dominated gaming industry. Despite making up almost half of the gamers globally, women made up only about 22% of the gaming industry workforce in 2020, according to Women in Games, a United Kingdom-based organization.

A blockbuster Chinese video game sparks debate on sexism in the nation’s gaming industry
A woman holds up an umbrella as it rains near an advertisement promoting the latest blockbuster new Chinese video game “Black Myth: Wukong” in Beijing, Friday, Aug. 23, 2024. Credit: AP Photo/Ng Han Guan

Skylar Hu, the only woman on her game engineering team of over 20 people, said her male colleagues often posted sexual jokes in work chat groups. She said when she told offenders to stop, her messages were ignored.

“Offensive jokes are so common and explicit,” Hu, 23, said in a phone interview, speaking on condition she be cited by her English name out of concern for her safety online.

For Jessica Hua, a former video game operation manager, controversy over the game reminded her of the toxic environment she experienced as a woman in the game industry.

“A lot of people think it’s just kidding around. But I cannot accept such misogynistic remarks,” said Hua. “I take it quite seriously.”

“Black Myth: Wukong” is China’s first-ever AAA game, a designation for big-budget productions akin to A-list movies. The game made history when over 2.4 million people played the game simultaneously online, breaking the record for most-played single-player game on Steam, a major online gaming platform. Three days after the game’s debut, over 10 million copies had been sold.

Many in the Chinese gaming industry say they regard the game as a point of national pride, promoting Chinese culture and challenging Western dominance in the industry.

A blockbuster Chinese video game sparks debate on sexism in the nation’s gaming industry
People walk past an advertisement promoting the latest blockbuster new Chinese video game “Black Myth: Wukong” in Beijing, Friday, Aug. 23, 2024. Credit: AP Photo/Ng Han Guan

“There is no doubt that this is a milestone in the Chinese gaming industry,” said Feng Xu, secretary of the Chengdu Cyber Game Industry Association. “It’s exporting authentic Chinese culture by introducing Monkey King to the world.”

China, which famously imposed limits on how long kids can play video games and sought to curtail excessive spending on online gaming, has shown full support for “Black Myth.” The government of China’s northwestern Shanxi province collaborated with the game’s developer to promote local tourism. State media have also published a series of articles praising the game.

Feng Xu says he doesn’t think the allegations against Game Science would have much impact on the game’s success. “Political correctness has nothing to do with the game,” he said. “We gamers only play the games, and we only care if the game is good and fun.”

Others say it was only a matter of time before addressing sexism in Chinese gaming culture gained more traction.

“Most game creators are men. You can see in a lot of games women are usually unnecessarily sexy and objectified,” said Ashley Li, a cultural critic and game enthusiast. “But I think this will gradually change in the future. We need to give it some time.”

© 2024 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.

Citation:
A blockbuster Chinese video game sparks debate on sexism in the nation’s gaming industry (2024, September 9)
retrieved 9 September 2024
from https://techxplore.com/news/2024-09-blockbuster-chinese-video-game-debate.html

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