【推荐1】Movies have documented America for more than one hundred years. Since Thomas Edison introduced the movie camera in 1893, amateur and professional movie-makers have used moving pictures to tell stories and explain the work of business and government.     1     By preserving these movies, we will save a century of history.

Unfortunately, movies are not made to last.     2     Already the losses are high. Only 20% of US feature films from the 1910s to 1920s survive. Of the American features produced before 1950, about half exist. For independently produced works, we have no way of knowing how much has been lost.

For many libraries and museums, the hardest step in preserving movie collections is getting started. The Movie Preservation Guide is designed for these organizations.     3     These institutions have collections of moving pictures but lack information about how to take care of them. The Guide contains basic facts for “beginners”—professionals trained in history but unschooled in this technical area.

The Guide grew from user workshops at Duke University. At the sessions, beginners talked with technical experts about what they needed to know to preserve and make available their movie collections.     4    

Following the advice, the Guide describes methods for handling and storing moving pictures that are practical for research institutions with limited resources.     5     The Guide has been translated into Chinese, Japanese and Korean.

【推荐2】Airport security is there to protect you, but it may also make you feel bad or worse.

To all the places and surfaces we've been warned that are filled with bacteria-your pets, the subway seats, airplane cabins, the A. T. M.- add the airport security tray.

The plastic trays have been found to harbor a variety of germs including the ones responsible for the common cold.

Scientists examined frequently touched surfaces at Helsinki Airport in Finland during and after busy hours in the winter of 2016 and picked up marks o£ the influenza A virus and rhino virus, the source of the common cold. They found traces on half the luggage trays, more than on any of the other surfaces they tested. None of these viruses were found on toilet surfaces at the airport.

The findings could help improve public health strategies in the fight against the spread of infectious diseases worldwide. The study could also help educate people on how the infections we try to avoid each winter spread.

Many of the surfaces we touch on a daily basis harbor and can spread germs. But air travel is known to accelerate the worldwide spread of diseases.

"The presence of bacteria in the environment of an airport has not been investigated previously, '' said Niina Ikonen, who was involved in the study. She added that the results provided new ideas for technical improvements in airport design and refurbishment(翻新).

The results of the study did not prove that the viruses found can cause disease. But previous research had proved that bacteria can survive on various surfaces for several days.

Washing your hands properly and coughing into a handkerchief tissue or sleeve can help minimize the risk of infection. Professor Van-Tam said, ''These simple precautions can help prevent infections and are most important in crowded areas like airports that have a high volume of people traveling to and from many different parts of the world".

【推荐3】Conventional wisdom says that hardship can make us old before our time. In fact, a new study suggests that violence not only leaves long-term scars on children’s bodies, but also changes their DNA, causing changes that are equal to seven to ten years of premature aging.

Scientists measured this by studying the ends of children’s chromosomes (染色体）, called telomeres(端粒), says Idan Shalev, lead author of a study published in Molecular Psychiatry.

Telomeres are special DNA sequences (序列）which prevent the DNA in chromosomes from separating. They get shorter each time a cell divides, until a cell cannot divide any more and dies.

Several factors have been found to shorten telomeres, including smoking, radiation and psychological stresses such as being treated badly when young and taking care of a chronically ill person.

In this study, researchers examined whether exposure to violence could make children’s telomeres shorten faster than normal. They interviewed the mothers of 236 children 3t ages 5, 7 and 10, asking whether the youngsters had been exposed to domestic violence between the mother and her partner; physical maltreatment by an adult; or bullying. Researchers measured the children's telomeres —in cells obtained by wiping the insides of their cheeks一at ages 5 and 10.

Telomeres shortened faster in kids exposed to two or more types of violence, says Shalev. Unless that pattern changes, the study suggests, these kids could be expected to develop diseases of aging, such as heart attacks or memory loss, seven to 10 years earlier than their peers.

Shlev says there is hope for these kids. His study found that, in rare cases, telomeres Better nutrition, exercise and stress reduction are three things that may be able to lengthen telomeres, he says.

The study confirms a small but growing number of studies suggesting that early childhood adversity imprints itself in our chromosomes, says Charles Nelson, a professor of pediatrics and neuroscience at Harvard Medical School.