Omar Vazquez grew up in poverty on Mexico's Yucatan peninsula. He watched his single mother struggle to put food on the table, and today the memory inspires him to help those in need. When an invasive (入侵的) seaweed called sargassum showed up on Mexico's Caribbean beaches, Omar looked past the matter of it all and saw an opportunity to help others.

Sargassum is not dangerous, but it has an unpleasant smell and can become so thick that it keeps people from entering the water. Mexico has experienced record-setting amounts of the seaweed in recent years, and it has made its way to Florida's beaches as well. Experts say there could be as much as 100 tons of sargassum blocking Mexican shorelines in 2023.

With tourism dollars at risk, officials and locals alike were eager to remove the seaweed, but only Omar saw its true potential. The professional gardener organized a beach cleanup that provided jobs for about 300 local families, but he knew there was more to do. Since people's attitude towards the seaweed reminded him of his own life experiences, he decided to become an agent (推动者) for change.

When sargassum started arriving, everyone was complaining. "I wanted to make something good out of something everyone saw as bad," Omar explained.

In 2018, Omar found a way to turn sargassum into building blocks that he calls Sargablock. He creates these blocks by mixing 40% sargassum with other materials like clay, then putting them in a block-forming machine and baking them in the sun for days. The end result is an organic, sustainable, and ecologically friendly building material that experts say could last for 120 years.

To date, Omar's company, Bluegreen Mexico, has used 700 tons of sargassum to build low-income housing for those in need. Omar said he would take on more projects, and donate more houses to single mothers like his own mom.

When John Todd was a child, he loved to explore the woods around his house, observing how nature solved problems. A dirty stream, for example, often became clear after flowing through plants and along rocks where tiny creatures lived. When he got older, John started to wonder if this process could be used to clean up the messes people were making.

After studying agriculture, medicine, and fisheries in college, John went back to observing nature and asking questions. Why can certain plants trap harmful bacteria (细菌)? Which kinds of fish can eat cancer-causing chemicals? With the right combination of animals and plants, he figured, maybe he could clean up waste the way nature did. He decided to build what he would later call an eco-machine.

The task John set for himself was to remove harmful substances from some sludge (污泥). First, he constructed a series of clear fiberglass tanks connected to each other. Then he went around to local ponds and streams and brought back some plants and animals. He placed them in the tanks and waited. Little by little, these different kinds of life got used to one another and formed their own ecosystem. After a few weeks, John added the sludge.

He was amazed at the results. The plants and animals in the eco-machine took the sludge as food and began to eat it! Within weeks, it had all been digested, and all that was left was pure water.

Over the years, John has taken on many big jobs. He developed a greenhouse-like facility that treated sewage (污水) from 1,600 homes in South Burlington. He also designed an eco-machine to clean canal water in Fuzhou, a city in southeast China.

"Ecological design" is the name John gives to what he does. "Life on Earth is kind of a box of spare parts for the inventor," he says. "You put organisms in new relationships and observe what's happening. Then you let these new systems develop their own ways to self-repair."

Many people think daydreaming is bad for their emotions and has negative effects on their life and those around them. It makes adapting to life very hard and brains work less effectively.

Contrary to common ideas, the brains of people who are daydreaming might not stop working, but may be working harder, new research has shown. Scientists scanned the brains of people lying inside magnetic resonance imaging（MRI）machines, as they pushed buttons or rested in turn. The scans showed that the "default（默认的）network" deep inside a human brain becomes more active during daydreaming.

In a surprise finding, the scans also showed strong activity in the executive network, the outlying region of the brain associated with complex problem-solving, says Professor Kalina Christoff, who is a co-author of the study. "People assume that when the mind wanders away, it just gets turned off but we show the opposite. When it wanders, it is turned on." says Christoff.

The findings, published in Proceedings of the National Academy of Sciences, suggest, "People who let themselves daydream might not think in the same focused way as when performing a goal-oriented task, but they bring in more mental and brain resources," says Christoff.

F. Diane Barth said at Psychology Today that the more we daydream, the more our brain is able to hold onto the task when we are being bombarded （轰炸）from all sides by all kinds of noises, information input, and conflicting demands. You're not trying to escape the task at hand; rather, you're trying to get rid of all of the information and stimuli（刺激物）that could pose as bothers.

According to Christoff, people typically spend one third of their waking time daydreaming. "It is a big part of our lives, but it has been largely ignored by science, she says. "The study is the first to use MRIs to study brain activity during spontaneous thoughts and subjective experiences. Until now the only way is to use self-reports that are not always reliable."