2 . Why are some people better able to fight off the flu than others? Part of the answer, according to a new study, is related to the first flu strain we encounter in childhood.

Scientists from UCLA and the University of Arizona have found that people’s ability to fight off the flu virus is determined not only by the subtypes of flu they have had throughout their lives, but also by the sequence (顺序) in which they have been infected by those viruses. Their study was published in the open- access journal PLoS Pathogens. The research offers an explanation for why some people become much worse than others when infected with the same strain of the flu virus.

In addition, UCLA scientists, including Professor James Lloyd Smith, who was also a senior author of the PLoS Pathogens research, recently completed a study that analyzed travel- related screening for the novel coronavirus 2019-nCoV. The researchers reported that screening travelers is not very effective for the 2019 coronavirus — that it will catch less than half of infected travelers, on average — and that most infected travelers are undetectable, meaning that they have no symptoms yet, and are unaware that they have been exposed. So stopping the spread of the virus is not simply a matter of enhancing screening methods at airports and other travel centers.

“This puts the onus on government officials and public health officials to follow up with travelers after they arrive, to isolate them and trace their contacts if they get sick later,” said Lloyd- Smith, a UCLA professor of eco logy and evolutionary biology. “Many governments have started to impose quarantines (隔离), or even travel bans, as they realize that screening is not sufficient to stop the spread of the coronavirus.”

One major concern, Lloyd-Smith said, is that other countries, especially developing nations, lack the infrastructure and resources for those measures, and are therefore vulnerable to importing the disease. “ Much of the public health world is very concerned about the virus being introduced into Africa or India, where large populations exist that do not have access to advanced medical care,” he said.

3 . Officer Michael Rivers, a policeman who was snapped (抓拍) and the image shared on Facebook, as he sat sharing his lunch with a homeless woman at the side of the road in North Carolina, in the USA, is praised.

According to Chris Barnes, his wife Cassie took the photo while she was on her lunch break. She saw the pair sharing a pizza and soft drink while they were having a friendly chat. Mr. Barnes uploaded the image with the notes: “Cassie was out on her lunch break and observed the officer enjoying lunch with a homeless person.”

Officer Rivers recalled seeing the woman earlier that day. He told Yahoo news: “I was leaving the parking lot of Walmart and she was standing by the stop sign. Her shirt read, ‘Homeless the fastest way of becoming a nobody.’ I hated that she felt that way.” He added: “I always try to talk to the homeless just to see how they got into their situation. You know, because it can happen to any one of us, at any given moment.”

After he drove away, he circled back to ask if the woman was hungry and if she wanted food. The officer said she was honoured by his offer. He bought them both pizza and Mountain Dew and when the pair sat down to eat, he learned of her family struggles and told her: “Hey, you still got stuff to live for, you still got your life ahead of you. It's never too late.”

Officer Rivers, who does recruiting (征兵) for the Goldsboro PD, hopes to send a message of sympathy for others. He added: “When the younger or newer guys come in, I let them know,‘Hey, treating the community like human beings is the most important thing in the world.”

“So, if we as police officers show that love and sympathy to everybody, no matter their age, financial background or race, the world would be a better place.”