神秘疾病与骆驼有关

2014-06-11 06:42
中学科技 2014年1期
关键词:骆驼中东研究者

在中东、欧洲和北非的某些地区,一种神秘的致命病毒已造成94人患病,46人死亡。一项新的研究发现:单峰骆驼可能是使人感染这种新型疾病的病原。

造成这种疾病的细菌是寄生在人体肺部、喉部和鼻腔的一种病毒,科学家们最近将这种病毒引起的疾病命名为“中东呼吸系统综合症”,或简称MERS。

在几名患者得了严重肺炎之后,科学家们发现了这种疾病。这种病情造成肺部发炎,损伤肺部。通过鉴定该细菌的DNA,研究者发现该病毒与感染蝙蝠的病毒有关,但是,没有发现患者曾经接触过蝙蝠。

现在研究者发现:中东阿曼50头已退役的赛跑型骆驼,它们的血液内携带抵抗MERS病毒的抗体。抗体是免疫系统内产生的蛋白质,它们能够识别或摧毁血液中的外来物质,它们在血液中的存在表明它们的宿主曾经遭遇过某些特定的外来物质。

单峰骆驼血液中抗体的发现,说明这些骆驼曾经接触过MERS。研究者还发现:非洲西北海岸附近的加那利群岛上的骆驼血液中也有MERS病毒抗体,只是抗体水平较低。

与病毒接触过的骆驼没有出现患病迹象,阿曼和加那利群岛也都没有报告人感染MERS的病例,但是未经证实的报告表明,其他国家的MERS患者可能得病前曾经接触过骆驼或山羊。(注意斜体字的译法)

Camels Linked to Mystery Disease

A mysterious and deadly virus has sickened 94 people - killing 46 - in parts of the Middle East, Europe and northern Africa. A new study finds that camels (the one-humped type) may have introduced the new disease to people.

The germ responsible is a virus that lives in people's lungs, throats and noses. Scientists recently named the disease it causes Middle East Respiratory Syndrome, or MERS.

Scientists discovered it after a few people became sick with severe pneumonia. This condition inflames and damages lungs. After examining the germ's DNA, researchers discovered that the virus is related to some that infect bats. But no one with the disease had any known contact with bats.

Now researchers find that 50 retired racing camels from the Middle East nation of Oman carry antibodies against the MERS virus in their blood. Antibodies are proteins made by the immune system. They help identify or destroy foreign substances in the blood. They also serve as a marker of which particular foreign substance their host had encountered.

Finding antibodies in the blood of dromedary camels suggests the animals had been exposed to MERS. The researchers also found low levels of antibodies against the MERS virus in the blood of dromedary camels from the Canary Islands, off of Africa's northwest coast.

None of the exposed camels appeared sick. And neither Oman nor the Canary Islands has reported human cases of MERS. But unconfirmed reports suggest some people with MERS in other countries may have been around camels or goats before falling ill.

How Cats See The World

What does the world look like through a cat's eyes? The basic (A) s of kitty eyes is pretty similar to what humans have, but cats vision has adapted to very different (1) p , so the world they see looks familiar, but isn't quite the same as ours. As predators, they need to be able to sense (B) m well in very low light. To make that work, they have to sacrifice some of the finer detail and color perception that (2) h have.

Artist Nickolay Lamm, who has previously brought us visualizations(可视性图像)of urban heat islands(热岛), took a look at the world through kitty eyes for his latest project. Lamm consulted with ophthalmologists(眼科医生)at the University of Pennsylvania's veterinary(兽医的)school and a few other animal eye (3) s to create these visualizations comparing how cats see with how humans do. Some of the cat-eye facts he took into account. Humans have a 20 degree range of peripheral (C) v on each side. Cats can see 30 degrees on each side. Their visual field overall is just bigger - they see 200 (4) d compared to our 180 degrees.

Cat vision isn't so great at a (5) d . What we can see sharply from 100 feet away, they need to see at 20 feet. From what (D) r can tell, cats can see blue and yellow (6) c , but not red, orange or brown colors. Cats can see some six to eight times better than us in the dark. Their elliptical pupils (瞳孔) can open very wide in dim light, but contract to a tiny slit to protect the sensitive retina from bright light.

(A, B, C, D FOR CROSS, 1, 2, 3, 4, 5, 6 FOR DOWN. The first letters of the absents were given)

The Government Subsidy Problem

The government pays farmers a specific fee for each row of four trees that they plant. An enterprising, but dishonest farmer found a way of planting five rows of four trees using only ten trees. How did he do it?

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