题型:阅读理解 题类:常考题 难易度:普通
云南省大理市下关第一中学2018-2019学年高一下学期英语期末考试试卷
Teenagers who talk on the phone a lot and hold their cell phones up to their right ears score worse on one type of memory test. That's the finding of a new study. That memory damage might be one side-effect of the radiation that phones use to keep us connected while we're on the go.
Nearly 700 Swiss teens took part in a test of figural memory. This type helps us recall abstract symbols and shapes, explains Milena Foerster. She's an epidemiologist(流行病学家). She worked on the study as part of a team while Foerster was at the Swiss Tropical and Public Health Institute in Basel, Switzerland. Teens participated memory tests twjce, one year apart. Each time, they had one minute to memorize 13 pairs of abstract shapes. Then they were shown one item from each pair and asked to match it with one of five choices.
The study volunteers also took a test of verbal memory. That's the ability to remember words. The two memory tests are parts of an intelligence test.
The researchers also surveyed the teens on how they use mobile phones. And they got call records from phone companies. The researchers used those records to estimate how long the teens were using their phones. This allowed the researchers to calculate how big a radiation exposure each person could have gotten while talking.
All cell phones give off energy in the form of radio frequency electromagnetic fields, or RF-EMFs. Radio and TV broadcasts also use this type of energy. So do microwave ovens and some other gadgets(配件).
"For a phone, that energy carries information, in the form of calls or texts between phones and cell phone towers. That radiation also can travel into people's bodies as they use their phones. And some of its energy can be absorbed by the body. So far, scientists have not shown that radiation from phones causes harm," says the Federal
Communications Commission. Research is ongoing, this agency notes.
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