In the last issue (Science Announces Top 10 Scientific Breakthroughs of 2023 (Part I)), we introduced the top five scientific breakthroughs of 2023 selected by its editorial team published by Science magazine, and in this issue we introduce five other major scientific breakthroughs of 2023.
The new ** in Alzheimer's disease
New antibodies** may slow neurodegeneration in the brains of people with Alzheimer's disease. **james c**allini/science source
In January of this year, U.S. regulators approved the first drug, which can significantly slow the rate of cognitive decline in people with Alzheimer's disease, followed by a second, related method. Neither approach can ** Alzheimer's disease, and both have serious risks, but they still offer new hope for patients and families.
People with Alzheimer's disease have tangled clumps of protein called amyloid in their brains, and for years, scientists have debated whether removing them would help. In an 18-month pivotal trial, an anti-amyloid monoclonal antibody called lecanemab slowed cognitive loss by 27 percent compared to a placebo. This was enough to convince regulators in the United States and Japan to approve it. Another antibody** method, which also targets amyloid, slowed the rate of cognitive decline by 35% compared to placebo in a slightly different patient population. The United States may ratify both at any time**. Both of these are intravenous.
It is important to note that the above ** can lead to the risk of brain swelling and cerebral hemorrhage, which, in rare cases, can be fatal. People with the genetic variant APOE4, a genetic variant that predisposes to Alzheimer's disease, are especially susceptible to this*** People with Alzheimer's disease who take medications to prevent or dissolve blood clots may also be at higher risk.
As people with Alzheimer's disease weigh the benefits and risks of anti-amyloid drugs, they are also eager for more data. One question is whether a modest slowdown in cognitive decline will increase over time;Another question is whether these ** can delay the onset of symptoms if they are given to high-risk groups as early as possible.
New discoveries about early humans in the Americas
Footprints on an ancient lake in New Mexico, USA, may predate archaeologists believe humans arrived in the Americas 5,000 years ago. **national park service
The story of the Americas may have opened a new first chapter. In mainstream opinion, the first immigrants from the Americas came from Asia, passing through the land that once connected the Bering Strait, and then at about 160,000 years ago the Pacific coast went south. This year, researchers are closer to confirming a claim that pushes that date back by at least 5,000 years.
Previously, some ruins suggested that people may have started the journey earlier than is widely believed. But no one has been able to provide clear evidence of human activity, so most archaeologists are skeptical.
In 2021, researchers at White Sands National Park in New Mexico, USA, found that as early as 230,000 years ago to 210,000 years ago, humans left their exact footprints on the muddy shores of an ancient lake. The researchers used radiocarbon dating to determine the seeds of an aquatic plant found in the strata surrounding the footprint to arrive at these dates. However, these seeds may have absorbed older carbon from the sediments dissolved in the lake water, affecting the accuracy of the dating. Therefore, the researchers re-dated the footprints using pollen from land plants and quartz grains embedded in the sediment between and below the footprints. In October of this year, they reported that the new assay timing was in perfect agreement with the initial assay results.
If the timing is correct, then the footprints were left at the peak of the last ice age, when the ice sheets covered Canada, suggesting that humans must have entered the Americas before these ice sheets were formed.
The sound of a giant black hole merging
***aurore simonnet/nanogr** collaboration
This year, astrophysicists discovered a faint, long-sought cosmic rumble. These are gravitational waves produced by supermassive black holes in the universe rubbing against each other. This observation is the strongest support for their existence to date and a strong proof of a method of detecting gravitational waves using signals from distant stars.
Supermassive black holes are located at the center of galaxies and weigh millions or billions of times as much as the Sun. When galaxies merge, the black holes at their centers may eventually be gravitationally locked in a shrinking orbit. In this initial phase, known as the "death spiral," ground-based instruments are unable to detect the signals, but as black holes get closer to each other within light-years, their mutual motion releases gravitational waves.
These gravitational waves cannot be detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO), which detected for the first time in 2015 the gravitational waves produced by the merger of two star-sized black holes. To sense these millisecond waves, Ligo measured the distance traveled by the laser beam along a 4-kilometer-long vacuum tube. But capturing the waves produced by supermassive black holes requires measuring longer distances.
As a result, astronomers turned to pulsars, which burn out stars that rotate hundreds of times per second while ejecting jets of particles carrying radio waves. As lighthouse-like waves pass across the Earth, radio telescopes record pulses that are as regular as atomic clocks. Over the past 20 years, astronomers have regularly monitored dozens of the most rhythmic pulsars for small changes in their pulse rhythms. Passing gravitational waves compress or stretch the space between the pulsar and Earth, subtly altering the time it takes for the pulse to reach Earth.
In June, five teams from around the world jointly announced that after 15 years of observation, they had reduced the noise in the data to a low enough level, and the rest of the data reflected the roar caused by the merger of supermassive black holes in the universe.
The rise of fledgling scientists
***danielvilleneuve/istock.com
For decades, graduate students and postdocs have complained about low pay and poor working conditions. Over the past year, their frustration has come into focus when early-career scientists have banded together to demand change.
Last winter, the University of California in the United States 480,000 people launched the largest academic strike in U.S. history, earning significant pay rises for graduate students and postdocs. In May of this year, thousands of academic workers in Canada held a large-scale, one-day event to demand increased funding for graduate students and postdocs. In Germany, early-career researchers are fighting for a change in their postdoctoral contracts.
Early career researchers are putting pressure on universities to leave academia altogether, and more and more are moving on to higher-paying industries after graduation.
Many faculty and university administrators agree that reform is needed, but dealing with budget pressures can also be challenging. It remains to be seen whether funding agencies will increase funding to cover the salaries of early-career researchers. At the same time, some universities have taken steps to help faculty adapt to the ever-increasing cost of personnel.
The dawn of exascale calculations
Exascale computers like the Frontier at Oak Ridge National Laboratory in the United States are bringing unprecedented computing power to many fields of science. **oak ridge national laboratory
After more than a decade in the making, the era of exascale computing science has finally arrived this year. Oak Ridge National Laboratory's Frontier is the first exascale computer to be open to scientific users, capable of handling challenges in everything from climate to materials at exascale (1018) operations per second.
The power of exascale calculations is already being felt. Materials scientists at the University of Michigan in the United States used Frontier to merge the two theoretical frameworks together to behave with near-perfect precision** the behavior of up to 600,000 electrons in a material, compared to about 1,000 electrons that previous calculations could only process. Lawrence Livermore National Laboratory and Sandia National Laboratory in the United States have used Frontier to improve the resolution of the U.S. Department of Energy's primary global climate model, which is expected to dramatically improve climate change accuracy.
About 60 teams are expected to use Frontier next year.
The exascale computational quest has only just begun. The exascale computer at Argonne National Laboratory in the United States is currently undergoing final commissioning and is ready to be opened to users. Next year, new exascale supercomputers are expected to be launched in the United States and Germany, followed by others in France and Japan, which will open the doors to science on an unprecedented scale.
end**: China Science Daily.
Author: Bunraku.
Review: Gong Zimo.
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