每日新闻播报（March 6）

>Super Tuesday 2020 results
美民主党预选两雄相争

The Democratic party's presidential field, which featured more than a half-dozen candidates a week ago, transformed into a two-man contest.
一周前，参加民主党总统候选人资格角逐的不止6人，现在则已经变成了两个人的较量。

A resurgent Joe Biden scored victories from Texas to Massachusetts on Super Tuesday, revitalizing a presidential bid that was teetering on the edge of disaster just days earlier.
乔·拜登实现大逆转，在"超级星期二"赢得了从得克萨斯到马萨诸塞各州的胜利，从而使几天前还处于灾难边缘的参选努力重获生机。

But his rival Bernie Sanders seized the biggest prize with a win in California that ensured he would drive the Democrats' nomination fight for the foreseeable future.
但他的对手伯尼·桑德斯凭借在加利福尼亚州的获胜赢得了最重要的战利品，这确保了他将在可预见的未来继续引领民主党的提名之争。

Biden drew support from a broad coalition of moderates and conservatives, African Americans and voters older than 45.
拜登得到了涵盖温和派和保守派的广泛联盟、非洲裔美国人以及45岁以上选民的支持。

Sanders' success was built on a base of energized liberals, young people and Latinos.
桑德斯的成功则建立在自由主义者、年轻人和拉美裔人士的基础上。

But he was unable to sufficiently widen his appeal to older voters and college graduates who make up a sizable share of Democratic voters, according to AP VoteCast.
但美联社的调查显示，他未能充分扩大自己对较年长选民和大学毕业生的吸引力，后者在民主党选民中占有相当大的比例。

>Arctic may see 'ice-free' summers
研究:北极将迎'无冰'夏季

A study suggests that the Arctic "may be essentially ice-free during summer within 15 years."
一项研究显示，北极"在15年内可能会在夏季基本无冰"。

The study used statistical models to predict the future amount of Arctic ice, which suggested that the Arctic could be ice-free in the summer during the decade of the 2030s – most likely in the year 2034.
该研究利用统计模型预测了北极冰层的未来数量，表明在21世纪30年代的十年里，极有可能是在2034年，北极可能会在夏季无冰。

Sea ice is frozen ocean water that melts each summer, then refreezes each winter.
海冰是冻结的海水，每年夏季融化，然后每年冬季重新冻结。

The amount of summer sea ice in the Arctic has been steadily shrinking over the past few decades because of global warming.
由于全球变暖，过去几十年来，北极夏季海冰的数量一直在稳步减少。

It reached its second-smallest level on record in 2019, the National Oceanic and Atmospheric Administration said.
美国国家海洋和大气管理局说，2019年北极夏季海冰水平仅次于历史最低记录。

What scientists refer to as the first "ice-free" Arctic summer year will occur when the Arctic has less than 1 million square kilometers of sea ice.
科学家所说的首个“无冰”北极夏季的年份将出现在北极海冰不足100万平方公里的时候。

>Carriers restart flights
国内航司逐步恢复航班

Chinese carriers have started resuming some of their domestic and international services that were suspended due to the novel coronavirus outbreak.
国内各家航空公司开始恢复运行部分因新冠肺炎疫情而暂停的国内和国际航班。

"Our services have been growing steadily since Feb 21. We expect more than half of the suspended flights to be operational by the middle of this month," said Zhang Wu'an, spokesperson of budget carrier Spring Airlines.
廉价航空春秋航空发言人张武安表示，春秋航空自2月21日起各条航线稳步恢复，到3月中旬，预计超过一半的暂停航线将恢复运行。

China Eastern Airlines, China Southern Airlines and Air China are also restoring their domestic and international flights.
东航、南航、国航也都在逐步恢复其国内和国际航班的运行。

Industry experts said the novel coronavirus outbreak dealt a great blow to the aviation sector, but the market will see a strong rebound after the country brings the epidemic under control.
业内专家称，虽然新冠肺炎疫情给航空业带来巨大的打击，但随着我国疫情得到控制，市场将迎来强劲反弹。

>Scientists find virus mutations
新冠病毒产生两种变体

Chinese scientists found that the coronavirus causing COVID-19 has two mutations, S-cov and the more dangerous L-cov, that features higher transmissibility and inflicts more harm to the human respiratory system.
我国科学家发现引发新冠病毒肺炎的冠状病毒已有两种突变，即S型和L型冠状病毒。L型冠状病毒的危险性和传染力更强，对人体呼吸系统造成的危害更大。

By analyzing the genome-wide molecular evolution of 103 novel coronavirus samples, scientists from Peking University's School of Life Sciences and Institut Pasteur of Shanghai, Chinese Academy of Sciences found 101 samples that can be categorized into S-cov and L-cov based on 149 mutation spots on virus strains.
北京大学生命科学学院和中国科学院上海巴斯德研究所的科学家对103个新冠病毒全基因组分子样本进化分析后发现，101个样本可根据病毒株上的149个突变点被分为S型和L型冠状病毒。

The research was published Tuesday in the National Science Review.
这项研究3日被发表在《国家科学评论》上。

The paper states that S-cov, accounting for 30%, is closer to the bat-related coronavirus and is relatively older, while the L-cov was more prevalent in the early stages of the outbreak in Wuhan but declined in early January.
论文称，S型冠状病毒占比30%，与蝙蝠相关的冠状病毒更接近且相对更加古老；而L型冠状病毒在武汉疫情暴发初期传播较广，但在1月初有所减弱。

Most patients were infected with only one of the two variants.
大多数病人仅感染了两种病毒变体中的一种。

But a sample from an American patient who had recently traveled to Wuhan suggested he might have been infected with both.
但最近到过武汉的一名美国病人的样本表明，他可能同时感染了这两种变体。

Scientists say the possibility of a third mutation cannot be ruled out.
科学家称，不排除第三种变体的可能性。

Medical experts said there might be more variants discovered as infections spike globally, since the mutation occurs from the virus adapting to different environments and hosts.
医学专家称，随着全球感染人数的激增，可能会发现更多的变体，因为病毒在适应不同环境和宿主时会产生突变。

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