【推荐2】I bet that your daily routine is probably something like mine, which is divided among seeing movies, streaming shopping videos and playing video games. All of these activities involve staring at a screen.    1    . So I turned to psychology experts for their advice. Here’s what we can do.

Come Up With a Plan. You should first assess which parts of screen time make you unhappy. That could be reading the news or scrolling through social media apps.    2    . You could set modest goals, such as a time limit of 20 minutes a day for reading news on weekends. If that works, shorten the time limit and make it a daily goal.

    3    . We need to recharge our phones overnight, but that doesn’t mean the devices need to be next to us while we sleep. Many studies have shown that people who keep phones in their bedrooms sleep more poorly. So you’d better have a charging station outside the bedroom. And we can create many no-phone zones outside our bedrooms.    4    .

Resist the Hooks (诱惑). Tech companies employed many techniques to make us addicted to their products. For example, the recommended video can be played automatically to keep users engaged. What to do? We can turn off notifications (通知) for all apps except those that are necessary.    5    . That said, we can remind ourselves that a lot of what we do online doesn’t matter, and it’s the time that can be better spent elsewhere.

【推荐3】The most common way of studying diversity is by setting camera traps. But a new study finds that a better answer might be in the water. Research finds sampling large amounts of stream water, looking for environmental DNA (eDNA) can measure the diversity of mammals just as effectively as camera trap monitoring.

“Camera trapping can trace a range of species effectively, but requires trained and skilled observers,” Arnaud Lyet, a conservation scientist says. “Besides, camera trap surveys are still too expensive to be used in large amounts.”

As animals move through the environment, they drop cells with DNA through their skin, hair, and feces. By sampling water, researchers can access that eDNA. The DNA in a sample is analyzed through a process which recognizes short sequences of DNA. These sequences are compared to those of known species in order to identify them.

For their work, in 2018 the researchers set up 57 camera traps and took water samples from 42 locations to match the camera traps in the South Chilcotin mountains in British Columbia. The next year, they kept the same camera, and collected 36 samples from only two large streams. They found the eDNA sampling detected the presence of 35 mammal species and cost $46,415. The camera trap survey detected 29 mammal species and cost $64,195.

“Our results suggest that the application of eDNA sampling strategies could change how biodiversity is monitored in large landscapes, providing decision-makers with more complete biodiversity data, improving our ability to safeguard biodiversity,” Lyet says. “A single sample containing eDNA can be used to potentially detect the presence of any organism from a bacteria to a large elephant. eDNA can be used to monitor endangered species, study the impact of climate change, warn us of invisible threats, and access the overall health of ecosystem.”