The Roman Colosseum is a giant amphitheater built two thousand years ago. Despite its age and an earthquake that knocked down its south side, most of the 150-some-foot building is still standing. Like many ancient Roman structures, parts of it were constructed using a specific type of concrete. Scientists and engineers have long suspected the key to these buildings’ strength is their use of this Roman concrete. But exactly how this strong concrete has contributed to the architecture’s durability (耐用) has been a mystery to researchers worldwide.

A team of interdisciplinary (跨学科的) researchers recently discovered a potential answer to why these ancient Roman buildings have been able to weather the test of time while many modern, concrete structures seem to collapse after a few decades. The answer: self-healing concrete. The material has three components: limestone. volcanic material and water. For years, architects and historians have guessed the volcanic material is what makes it strong — which it does. But it does not explain the material’s self-healing ability.

What the researchers found was that the self-healing properties might simply be a result of chemistry. The limestone in the concrete is likely the secret. When the ancient Romans made mortar (砂浆), they heated up the lime to turn it into a substance called “quicklime” — a very reactive chemical sibling to limestone. And, because they introduced water to the quickli me during mixing, the heat it produced set up a chemical foundation that could strengthen the concrete later. When tiny cracks start to form later, the quicklime stops them from becoming bigger. When it rains, the lime quickly fills the crack or reacts with the volcanic ash to“heal”the material.

For materials scientist Ainissa Ramirez, this new understanding of ancient Roman con crete is a welcome discovery. “This is one way that the material can be greener,” says Ramirez. “It’s sort of like a message in a bottle. The Romans made the material. We had to kind of figure out how they did it so that we can make better materials — and then in turn, attend to our environment better.”

Google researchers have developed an AI tool, called MusicLM, which is designed to create music based on a set of descriptive words. While it is not the first AI music tool to launch, MusicLM demonstrates remarkable creative ability in generating music from limited inputs. To use the system, users enter words that describe the type of music they want to create, such as “a continuous calming violin backed by a soft guitar sound”. These descriptions can include different music styles, instruments, or existing sounds. The more detailed the description, the better the system can attempt to produce the desired music.

MusicLM has generated several examples of music based on one or two-word descriptions such as “jazz” or “techno”. The system can also create music from more detailed descriptions containing whole sentences. The resulting music closely matches the input description. According to the team, the system can also generate music based on a person's own singing, whistling, or playing an instrument. It produces high-quality music that can last several minutes while being staunch to the written descriptions.

Although the MusicLM system is not yet available to the public, Google has released a dataset (数据集)of more than 5, 500 music-writing pairs, prepared by professional musicians called MusicCaps. This dataset can help advance the progress of other AI music generators.

The MusicLM system is an exciting development in the field of AI-generated music. It has the potential to help users quickly and easily create high-quality music. However, the team also acknowledges that machine learning has some risks associated with it. Just like any emerging technology, it is vital to thoughtfully examine and resolve any ethical issues that may surface.

In conclusion, MusicLM is a promising tool that can generate high-quality music based on limited inputs. Its ability to create music from descriptions, singing, whistling, or playing an instrument is impressive. While its potential is exciting, it is crucial to address any ethical concerns that may arise from using this new technology.