3 . Engineers took those situations into account when building out their concept drone. They recorded themselves screaming, tapping and creating other noises that might be a sign of people in trouble. Then, they analyzed each sound frequency to find common signatures and used those to train artificial intelligence software. They also worked to remove the noise created by the drone and other environmental sounds.

Once the software part was complete, the team placed tiny digital microphones under the drone and used signal processing techniques that enabled them to track where human noises are coming from. The microphones also enhanced the volume and clarity of the speech. So far, they have conducted successful open field experiments, finding that the drone can estimate a victim’s location within a few seconds of picking up sound.

4 . “Your password has expired,” a message said on my screen, with instructions for changing it. Coming up with a new code doesn’t seem like a big deal, unless you work at my company, where we have to change it monthly, using at least one uppercase character, one lowercase character, one symbol, and one number. Oh, the whole password can’t be fewer than eight characters. And I can’t use any of the same passwords I’ve used in the past three months.

5 . When Hal Donaldson was 23, fresh out of college and found himself in India, where he was writing a book for a couple feeding hungry children. He was told that there was someone he had to interview. It was Mother Teresa. After their interview, Mother Teresa had a question for him, “What are you doing to help the poor?” He told her the truth that he wasn’t focused on helping others. With a smile on her face, Mother Teresa said, “Everyone can do something.”

Donaldson returned home from India with a changed perspective. He knew he needed to do something to help others. He packed up his car and hit the road. He travelled to eight cities in America and stayed on the streets for three nights in each of them. He spent that time talking with the people he came across and he listened to their stories. “My heart broke,” he says. “I knew I could no longer just live for myself.”

6 . In a new study published on the Journal of Auian Biology researchers at the National Autonomous University of Mexico tracked the behavior of house finches (雀) on the main campus of the university, in Mexico City.

The team created an artificial nest lining (内衬), which includes feathers, cotton, hair and cigarette ends. Then, after the birds’ eggs had hatched, they replaced the original lining with the new one, to make sure the nests were pest free. The researchers then added live ticks to the mix, while dead ticks were added to other linings.

7 . Qatar’s Mutaz Essa Barshim and Italy’s Gianmarco Tamberi were competing in the high jump on Sunday when they reached a stalemate (僵局). Both men had managed to jump over a surprising 2.37 meters with no faults along the way. However, after three attempts neither managed the next level of 2.39 meters.

An Olympic official suggested a jump-off between the two friends and rivals (竞争对手) to determine who would get the gold medal. But Barshim had another plan to reward their efforts.

8 . Katie also designed her very own “No Hungry Children” T-shirt, which is available for purchase online. A part of the proceeds from her T-shirt sales economically supports Katie’s efforts, as well as the work of Amazing Kids, a nonprofit organization that focuses on the dreams of kids like Katie.

“I think it is important to have something to strive for,” says Katie. “By planting a garden or just some seeds in a pot you can make a difference. My cabbage alone fed 275 people. If more kids did the same, we all could be helping to make a long-time dream of no hungry people possible.”

9 . Saltwater crocodiles are the largest reptile in the world and can eat large prey (猎物). They hide at the edge of the water, waiting for prey. Then, without warning, they lunge. They grab their prey in their powerful jaws and drag it under water. Saltwater crocodiles don’t often miss their target.

One day, David George found himself in a swamp. It was the home of saltwater crocodiles. David knew they were there because he could see their tracks.

David thought his only chance of survival was to climb a tree and tie himself to a branch. Two big saltwater crocodiles, however, waited under the tree. He would have to come down sometime!

10 . Lisa and her husband Eddie took Harry to the doctor many times over the next year, but were told it was simply a virus and the condition wouldn't affect his older brother, Oliver. At six months Harry was diagnosed with several food allergies, which doctors thought might have caused the bumps. But Harry continued to get the bumps even after shunning those foods. Out of desperation, the family took Harry to Great Ormond Street Hospital to see a private specialist. By coincidence, Harry got the bumps when they were waiting to see the consultant. So the consultant saw exactly how severe it was. And Harry was diagnosed with physical urticaria (荨麻疹), a skin allergy to a host of common triggers (触发物). Since the diagnosis, Harry’s condition has greatly improved.