【推荐2】Scientists in the U.S. have created an artificial sunflower less than 0. 04 inches wide that can bend towards a light source and harvest solar energy. The flowers were found to be about 400 percent more efficient than other equipment, making them promising technology for solar power potentially even as a power source for solar-based spaceships.

The team, led by researchers from the University of California, Los Angeles, was looking to improve. the efficiency of solar cells by modeling after a feature of nature-phototropism. This is where a plant adjusts itself to face the sun, getting the most amount of energy it can get. In a study published in Nature Nanotechnology, the team said it was a ''big challenge''.

However, this problem has now been overcome. The team has developed a polymer(聚合物) that is responsive to being simulated by light, The system, which they have named SunBOT for short, is able to instantly explore and track a light source. It can do this across a range of temperatures without power supply or any human intervention.

The researchers used the polymer to create a ''stem''. Then they placed a material commonly used in solar cells on its top, representing the ''flower''. When the team shone a light at the SunBOTs, the polymer began heating up and shrinking, causing the stem to bend so the flower faced the light.

The researchers tested their artificial sunflowers to see how efficient they were at harvesting solar energy Findings showed they were up to 400 percent more effective than non-phototrophic materials.

The practical applications of SunBOTs are some way off. The study shows a proof of concept, but the technology will need to be scaled up to be used commercially. However, the team is confident it could one day be used a across a broad range of industries.

This work may be useful for solar harvesters signal revere smart windows, self-contained robotics solar sails for spaceships and intelligent energy generation (for example, solar cells and biofuels), the scientific team said.

【推荐2】Scientists have long known that humans are built for endurance. Now, a new study shows people's hearts are also bettered for endurance — though how much depends on whether we run, farm, or stay put on the sofa.

To get to the heart of the matter, researchers examined the hearts of more than 160 adult men from four groups: long-distance runners, sedentary adults, highly trained football player, and the Tarahumara, native American farmers famous for their running ability.

When researchers compared the thickest of the heart's ventricles, they found there were clear differences. Endurance runners and farmers had larger, longer ventricles with thin walls, which could help pump more blood for a long time, the researchers report today in the Proceedings of the National Academy of Sciences. The football player, whose training was short, high-intensity exercise, had shorter, wider ventricles with thicker walls. So did the sedentary humans.

Because high-intensity activity causes blood pressure to increase for a short amount of time, such shorter ventricle, thick walls, and rounder shapes are good for the football players, researchers say, by making sure enough blood is pumped to the brain. But even without those pressures, a couch potato lifestyle seems to result in the same kind of thickening.

But sedentary readers shouldn't feel heartbroken — the researchers said that changes in heart shape are likely reversible, with more endurance activities.

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【推荐3】Technologies like Artificial Intelligence, Big Data, GIS and Mapping, Location Technology and autonomous machines are playing a growing role in responding to COVID-19 pandemic.

An important policy for authorities across the globe right now is to prevent the spread of the virus. To ensure it, they are taking unprecedented （空前的） measures to reduce people-to-people contact. Most countries took measures like the closure of non-essential public places, ban of mass gatherings and ensuring a social distancing to limit physical contact.

However, in some areas where individuals are not obeying the restrictions knowingly or unknowingly, or do not know what the latest restrictions are, law enforcing authorities are using drones （无人机） to monitor people' s movement and break up social gatherings that could cause a risk to society. The introduction of drones at this time of crisis is reducing the risk of getting infected to police officials and other staff since it enables them to monitor a vast range of area without physical engagement.

In addition to street monitoring, authorities are also using drones to broadcast messages and information about lockdown measures, especially in rural area that lacks open communication channels for health information. Drones equipped with loudspeakers are used to make public announcements to keep people indoors, take necessary preventive measures, make social-distancing and wear a mask if stepping outside from home.

A Global Times video on Twitter shows a drone flying over a village in Inner Mongolia, warning an old lady with audio in Chinese, “Yes, Grandmother, it’s the drone who is talking to you. You should not go out without wearing a mask. You’d better go home and don' t forget to wash your hands.”

However, the use of drones raises a debate about privacy and individual rights on mainstream media as well as social media platforms.