【推荐2】The San Diego County Water Authority has an unusual plan to use the city’s scenic San Vicente Reservoir (水库) to store solar power so it’s available after sunset. The project could help unlock America’s clean energy future.

Perhaps ten years from now, if all goes smoothly, large underground pipes will connect this lake to a new reservoir, a much smaller one, built in a nearby valley about 1100 feet higher. When the sun is high in the sky, California’s abundant solar power will pump water into that upper reservoir. It’s a way to store the electricity. When the sun goes down and solar power disappears, operators would open a valve (阀门) and the force of 8 million tons of water, falling back downhill through those same pipes, would drive machines capable of producing 500 megawatts of electricity for up to eight hours. That’s enough to power 130, 000 typical homes.

“It’s a water battery!” says Neena Kuzmich, Deputy Director of Engineering for the water authority. She says energy storage facilities like these will be increasingly important as California starts to rely more on energy from wind and solar, which produce electricity on their own schedules, without considering the demands of consumers.

Californians learned this during a heat wave this past summer. “Everybody in the state of California got a text message at 5:30 in the evening to turn off their appliances,” Kuzmich says. The sun was going down, solar generation was disappearing, and the remaining power plants, many of them burning gas, couldn’t keep up with demand. The reminder worked:People stopped using so much power, and the grid (电网) survived.

Yet earlier on that same day, there was so much solar power available that the grid couldn’t take it all. Grid operators turned away more than 2000 megawatt hours of electricity that solar generators could have delivered, enough to power a small city. That electricity was wasted. There was no way to store it for later, when operators desperately needed it.

【推荐3】Global food demand will double by 2050, according to a new projection, and the farming techniques used to meet that unprecedented(空前的) demand will significantly determine how severe the impact is on the environment, researchers said.

The study researchers warned that meeting the demand for food would clear more land, increase nitrogen(氮) use and significantly add to carbon dioxide and other greenhouse gas emissions.

“Agriculture’s greenhouse gas emissions could double by 2050 if current trends in global food production continue,” study researcher David Tilman, of the University of Minnesota, said in a statement. “This would be a major problem, since global agriculture already accounts for a third of all greenhouse gas emissions.”

The researchers studied various ways in which the increasing food demand could be mentioned. They found that the most environmentally friendly and cost-effective approach would be for more food producers to adopt the nitrogen-efficient “intensive” farming method, which involves the heavy use of labor and the production of more crops per acre.

This approach was shown to be more effective than the “extensive” farming currently practiced by many poor nations, a method that includes clearing more new land to produce more food.

Different farming methods produce significantly different yields, the researchers found — in 2005, the crop yields for the wealthiest nations were more than 300 percent higher than what the poorest nations produced.

According to their analysis of the effects of extensive farming, if poorer nations continue using this method, by 2050 they will have cleared an area larger than the United States, about 2.5 billion acres. However, if wealthy nations help poorer nations to improve food yields by incorporating(吸收) intensive farming practices, that number could be reduced to half a billion acres.

The researchers stress that the environmental effects of meeting future food demand depend on how global agriculture expands and develops.

“Our analyses show that we can save most of the Earth’s remaining ecosystems by helping the poorer nations of the world feed themselves,” Tilman said.

【推荐1】Dogs may appear to have selective hearing when it comes to commands (指令) but research suggests they are paying attention to human chitchat.

Researchers, who arranged for headphone-wearing dogs to listen to excerpts (节录) from the novel   The   Little   Prince,   revealed their brains can tell the difference between speech and non-speech when listening to human voices, and show different responses to speech in an unfamiliar language.

The research involved 18 dogs of various ages and breeds (品种) that were trained to lie in an MRI scanner with headphones on. They were then played recordings either of humans reading excerpts from The Little Prince or those same recordings cut up into small pieces and put back together in a different order so it sounded unnatural.

The results, published in the journal NeuroImage, revealed the dogs’ brains showed a different activity pattern in the primary auditory cortex (听觉皮层) for speech compared with non-speech, with the findings similar regardless of whether the language used — Hungarian or Spanish — was familiar. Curiously, the longer the dog’s head was, the better their brain could distinguish speech from non-speech.

The team also found the activity pattern was stronger for non-speech.In humans, we typically see stronger response to speech.

The research also revealed familiar and unfamiliar languages gave rise to different responses in the secondary auditory cortex —but only for speech. That was important, said Andics, senior author of the study at Eötvös Loránd University in Hungary,   as it suggested the ability to distinguish between languages was not simply down to the speakers being different.

Instead, the team said, the differences seen between languages for speech are probably down to exposure to the familiar language and a sensitivity to language-specific regularities.

“This is also supported by the observation that older dogs show the stronger discrimination between the two languages,” said Andics.

【推荐2】Some of the oldest living things on our remarkable planet are trees. The record holders are bristlecone pines (狐尾松) of the western United States, quite a few of which are known to be more than 3,000 years old. One individual, discovered in 2012, is estimated to be more than 5,060 years old, making it the oldest known non-clonal tree in the world!     1    : individuals across a number of other tree species have also been around for thousands of years.

So, how do trees survive for thousands of years?     2    . Undoubtedly, part of the answer lies in luck. Ancient trees have obviously not submitted to deadly diseases, pests, fires, droughts, windstorms, landslides, or the human axe in the centuries and centuries that they have quietly endured.

The other part of the answer has to do with how trees age. In fact, there is quite a debate about whether ancient trees can be considered “immortal (永生的)”. That is, will such trees ever die if they are not killed by an outside force? We may never know the answer to that, but, at the very least,     3    . While cell death is an important factor in the aging of humans and other animals, one study found little evidence of cell death in the ginkgo tree vascular cambium (银杏树维管形成层). In addition, a study of bristlecone pine pollen (花粉) found no significant increase in mutation (变异) rates with age, which is another factor associated with animal aging.     4    .

Older trees benefit greatly from having bodies made mostly of dead woody tissue. In fact, an old tree might be as much as 95 percent dead tissue! Given that it isn’t alive, wood does not require metabolic (新陈代谢的) activity to maintain it,     5    .