A new study establishes that environmental damage caused by corn production results in 4,300 premature deaths annually in the United States, representing cost of $39 billion.

The paper, published in the peer-reviewed journal Nature Sustainability, presents how researchers have estimated for the first time the health damages caused by corn production using detailed information on pollution emissions, pollution transport by wind, and human exposure to increased air pollution levels.

The study also shows how the damage to human health of producing a litre (升) of corn differs from region to region and how, in some areas, the health damages of corn production are greater than its market price.

“The deaths caused per litre in western corn belt states such as Minnesota, Iowa, and Nebraska tend to be lower than in eastern corn belt states such as Illinois, Indiana, and Ohio,” said lead researcher Jason Hill.

It’s important for farmers to have this information so that they can carry out practices that reduce the environmental influence of the crops they grow. Farmers can greatly improve the environmental profile of their corn by using precision agriculture tools and switching to fertilizers that have lower ammonia (氨) emissions. The study’s results also suggest potential benefits from improving nitrogen use efficiency, switching to crops requiring less fertilizer, and changing the location where corn is grown.

Aware that changes in practices can take time and planning, Hill suggests farmers could be offered motivation to switch to crops that demand less applied nitrogen while still offering market and nutritional benefits.

Hill said, “The number of deaths related to corn production could be reduced through these key strategies”.

A new paper summarizes the evidence for letting kids loose. 【小题1】. It is building brain. Here are some of the research findings that appear in the paper.

【小题2】.

In order to grow healthy, our brains need plenty of something called BDNF (脑源性神经营养因子). Studies show what happened when young rats were allowed to fight and play together. Half an hour of this kind of play actually changed the expression of their genes in a way that promoted the production of BDNF.

Toddlers with plenty of chances to run, jump and climb grow into kids who are physically confident and more likely to be active and healthy adults. 【小题3】. The study shows that the kids who got at least an hour a day of outdoor play showed significant improvement in their body mass indexes. Those who got the most outdoor time were 42 percent less likely to be overweight by the end of the year.

Play is also important for building relationships between parents and kids. The conversations with kids that come out in play are brain-builders. 【小题4】. It in turn can help children learn to regulate their emotions when the cookie breaks.

No, everything doesn’t have to be about test scores! But play is also good for test scores. This paper argues that at tender ages, improvisational pretend-play, not direct instruction, is what really feeds both language development and general knowledge, not to mention, again, kids’ intrinsic motivation. Experts suggest that parents start small. Playing with blocks for even two minutes helps you use words together. 【小题5】.

When you eagerly dig into a long-awaited dinner, it’s traditionally believed that signals from your stomach to your brain stop you eating so much. However, a research team recently discovered that it’s our sense of taste that immediately pulls us back from eating food overly on a hungry day. Stimulated by the perception of flavor, a set of brain cells become active to quickly curtail food intake.

Previous studies have suggested that the food taste may control how fast we eat, but it’s been impossible to study relevant brain activities during eating because brain cells that control this process are located deep in our brains, making them hard to access or record in an awake animal. New techniques developed by the team allowed for the first-ever imaging and recording of a brainstem structure critical for feeling full, called NTS, in an active mouse.

The new study found that when researchers put food directly into the mouse’s stomach, brain cells called PRLH were activated by signals from the gut (消化道), in line with traditional thinking. However, when they allowed the mice to eat the food as they normally would, those signals from the gut didn’t show up. Instead, the PRLH brain cells switched to a new activity pattern that was entirely controlled by signals from the mouth. “It’s astonishing that these cells were activated by the perception of taste,” said researchers. “It shows that there are other components of the appetite-control system that deserves our attention.”

The PRLH-activated slowdown also makes sense in terms of timing. The taste of food allows PRLH to switch their activity in seconds. In contrast, another group of brain cells, called CGC, takes several minutes to respond to signals from the gut. The good thing is that CGC can hold back hunger for a much longer time. These two sets of brain cells interact to work together: one uses taste to slow down eating, while the other signals that you are full.