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August 15(Thursday) News, the main content of the well-known foreign scientific website is as follows:

Nature website (www.nature.com)

Geology's Greatest Mystery: When Did Plate Tectonics Start Reshaping the Earth?

Earthquakes occur frequently because the Earth's crust is divided into constantly shifting tectonic plates. The forces of plate tectonics determine nearly everything from climate to the evolution of life.

Despite the importance of plate tectonics on Earth, exactly when it began remains a mystery. Since the early 21st century, geologists have been collecting data to try to answer when and how plate tectonics began. These studies have produced many, often conflicting results.

However, over the past decade, scientists have gradually formed a consensus that a key shift in the Earth's crust occurred around 3 billion years ago: there is a lot of evidence that tectonic activity at that time changed profoundly. For example, a 2016 study found that the composition of the Earth's crust began to change around 3 billion years ago.

Other studies have suggested that the transformation of the Earth's crust may have occurred even earlier. Some studies have suggested that Earth was subducting as early as 3 billion years ago or even 3.8 billion years ago. However, there is still much debate about the extent of this early subduction.

Some studies have shown, using simulated impacts, that some subduction may have been triggered by meteorite impacts, and a 2022 study of Archean continental crust concluded that subduction was only localized until at least 2.7 billion years ago.

In contrast, true plate tectonics is global and ongoing, and the researchers note that solid evidence for this only emerged about 2.2 billion years ago, when an ancient supercontinent known as Nuna or Columbia was forming, reflecting a global process.

Even so, the system has continued to evolve since then. Rocks such as blueschists, which can only form when subducting rocks are dense and cool and sink deep into the mantle, appear in the rock record around 800 million years ago, leading some researchers to believe that Earth's modern plate tectonics did not really begin until then.

Science News website (www.sciencenews.org)

Scientists propose building a "lunar ark" to store cells from endangered species on Earth

As more species become extinct, scientists have been collecting samples of animals, plants and other organisms and storing them in biobanks around the world. But the threat of climate change, environmental disasters and war puts these modern-day Noah's Arks at risk. To this end, a group of researchers is exploring the possibility of building such an ark on the moon.

The biological repositories located in the permanently shadowed regions of the lunar south pole may be more stable than any on Earth. Mary Hagedorn, a scientist at the Smithsonian's National Zoo and Conservation Biology Institute, and her team recently reported in the journal BioScience that the temperature in these areas is usually kept at around -196 degrees Celsius, suitable for long-term storage of most animal cells.

The team was inspired by the Global Seed Vault on the Norwegian island of Svalbard, which uses Arctic cold to preserve millions of seeds from around the world. However, in 2017, melting permafrost flooded the vault, putting its precious seeds at risk. This incident and others like it highlight the importance of having a backup plan.

A few years later, another team proposed building a lunar ark in a lava tube beneath the lunar surface, but this would require a solar-powered cooling system; if the power supply was lost, the samples would be destroyed. Hegedorn's team believes that in the permanently frozen shadows of the moon, the lunar ark would not require energy or constant human maintenance.

Challenges facing the new proposal include how to deal with the long-term effects of radiation and microgravity on the samples. Hegedorn and his colleagues are designing radiation-proof sample storage containers, and the next step is to test these prototypes on future lunar missions.

Science Daily website (www.sciencedaily.com)

1. How bread helped civilization emerge: The secret of how bread wheat became the world's dominant crop

An important international study has revealed how bread wheat helped transform ancient civilizations into a staple food crop for eight billion people today. The study, conducted by the Open Wild Wheat Consortium (OWWC) and published in the journal Nature, suggests that the secret to bread wheat's success lies in the genetic diversity of a wild grass called Aegilops tauschii.

Bread wheat is a hybrid of three wild grasses, including the A, B and D genomes, which form a complex plant family. The D genome was provided by a humble wild grass, Aegilops truncatula, that hybridized with early wheat plants on the southern coast of the Caspian Sea between 8,000 and 11,000 years ago.

This accidental crossbred gave rise to an agricultural revolution. Bread wheat quickly expanded into new climates and soils, and was embraced by farmers. Its high gluten content gave the dough more elasticity, allowing for bread with better structure.

The researchers stressed that without the genetic dynamism brought about by this genetic diversity, bread wheat would not have become the dominant crop so widely grown around the world today. It is this adaptability that has enabled bread wheat to become a mainstay of global agriculture.

2. Work-related stress will increaseArrhythmiasrisk

Job stress, caused by job pressure and an imbalance between effort and reward, may increase the risk of heart disease, according to a new study published in the Journal of the American Heart Association.Atrial fibrillationrisk.

Atrial fibrillation (AFib) is the most common type of arrhythmia and can lead to cardiovascular complications such as stroke and heart failure. According to the American Heart Association in 2024, it is estimated that by 2030, more than 12 million people in the United States will suffer from atrial fibrillation.

Previous studies have linked high job stress to an increased risk of coronary heart disease. This study is the first to examine the adverse effects of psychosocial stress at work on atrial fibrillation.

The research team analyzed the medical records of nearly 6,000 white-collar adults in Canada and conducted an 18-year follow-up survey. The results showed that employees who reported high work stress had an 83% higher risk of atrial fibrillation than those who did not feel stressed, and those who felt an imbalance between effort and reward had a 44% higher risk of disease than other employees. Employees who felt both high work stress and an imbalance between effort and reward had a 97% increased risk of atrial fibrillation.

A limitation of the study is that the participants were white-collar workers, including managers, professionals and office workers, so the results may not apply to employees in other jobs or in other countries.

Scitech Daily website (https://scitechdaily.com)

1. "Almost no value" - study finds sprayInsecticidesUnable to control cockroaches

A new study shows that residual insecticides are mostly ineffective for controlling cockroaches. Such insecticides are designed to be sprayed on surfaces where cockroaches are likely to appear so that the roaches are exposed to the toxic ingredients as they pass by. However, researchers at the University of Kentucky and Auburn University in the United States found in laboratory tests that these insecticides have very limited effectiveness against German cockroaches.

The German cockroach is one of the most common pests in homes and buildings around the world, known for its rapid reproduction and resistance to many common pesticides.

The study found that liquid and aerosol sprays of pyrethroid insecticides killed less than 20% of German cockroaches when they were exposed to the spray surface for 30 minutes. Even when the cockroaches were confined to the spray surface, most products took eight to 24 hours to kill the cockroaches, and some took as long as five days. The study, published in the Journal of Economic Entomology, tested the spray on German cockroaches collected from real-world cockroach infestations. Previous studies have shown that these insects have evolved resistance to pyrethroids.

The researchers note that while cockroach control can be challenging, it can still be done effectively by taking certain measures. However, this usually requires a lot of time and is costly. They specifically mention that German cockroaches are generally resistant to pyrethroid insecticides, which is a major challenge in controlling this pest.

2. Climate change may make soil more toxic in surprising ways

The Minamata Convention on Mercury (Minamata Convention) has been in force since 2017 to help control mercury emissions and limit mercury exposure worldwide. However, a new treaty on mercury in soil hasMercury contentNew research from the European Commission suggests that mercury levels in soil could increase even more due to increased plant growth that could result from climate change, suggesting that the Minamata Convention's regulations may need further refinement.

The study, published in the American Chemical Society journal Environmental Science & Technology, was conducted by Professor Wang Xuejun and his team at Peking University's College of Urban and Environmental Sciences, who developed a more accurate global model of soil mercury levels that takes into account the effects of climate change.

The model found that the total amount of mercury stored in the Earth's top 1 meter of soil is about 4.7 million tons, which is twice as much as previously estimated. The study also found that mercury levels are highest in densely vegetated areas, such as tropical low latitudes, while mercury levels are also higher in permafrost and densely populated areas. In contrast, bare land such as shrubs or grasslands have relatively low mercury levels in the soil.

Projections suggest that as global temperatures rise, vegetation growth will be promoted, which in turn could increase mercury levels in soils. This symbiotic effect could outweigh the reductions that current global control plans can achieve.

The study highlights the need for stricter, long-term and simultaneous control of mercury and carbon dioxide emissions.