VOA慢速英语2012 SCIENCE IN THE NEWS - Tons Of Methane Gas Could Be Trapped Under Antarctica

 

SCIENCE IN THE NEWS - Tons Of Methane¹ Gas Could Be Trapped Under Antarctica

BOB DOUGHTY²: This is SCIENCE IN THE NEWS, in VOA Special English. I’m Bob Doughty.

SHIRLEY GRIFFITH: And I’m Shirley Griffith. Today, we tell about methane gas thought to be trapped under ice-covered areas of Antarctica. We also tell about the growing use of generic³ drugs in fighting HIV, the virus responsible for AIDS. And we have a report on the search for an effective vaccine⁴ against HIV.

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BOB DOUGHTY: An international team of scientists has found that up to four billion tons of methane gas could be trapped under ice-covered areas of Antarctica. The scientists say extremely small organisms may have changed ancient organic matter into methane. And they say if enough ice melts, it is possible that enough of the gas could escape and add to the warming of Earth’s atmosphere. 

Jemima Wadham of Bristol University in Britain directed the study. She says the amount of organic carbon recorded is more than ten times the size of all carbon supplies in Earth’s northern permafrost areas. The journal Nature published her report about the findings.

Sandra Arndt also worked on the study. At the time, she was with Utrecht University in The Netherlands. She says the high pressure and cold temperatures under the ice make good conditions for forming methane hydrate. And she says it was not surprising that the study confirmed the presence of methane hydrate. The substance is a solid similar to ice. It is formed when methane gets trapped within a structure of water molecules⁵. 

SHIRLEY GRIFFITH: The continent of Antarctica is mainly over the South Pole, almost totally south of the Arctic Circle. The scientists say the organic material came from a period thirty five million years ago. At that time, Antarctica was much warmer than today and contained life forms.

Researcher Slawek Tulaczyk of the University of California at Santa Barbara described how methane formed. She said some of the organic material became trapped in material that had fallen to the bottom. She said these sediments⁶, in her words, were then “cut off from the rest of the world when the ice sheet grew.”

The scientists say fifty percent of the West Antarctic ice sheet and twenty-five percent of the East Antarctic sheet are on sedimentary basins. They said these areas hold about twenty one billion tons of carbon.

BOB DOUGHTY: The Antarctic Ice Sheet covers land, but not the surrounding sea. Methane hydrates are also found at the bottom of oceans. 

Earlier this year, news about methane gas came from the opposite end of the world. Researchers reported finding thousands of places in the Arctic where the gas was rising to the surface. 

Studies on the ground and from the air found one hundred fifty thousand seeps⁷ -- places in Alaska and Greenland where methane had escaped. The seeps were found in lakes along the edges of ice cover.

SHIRLEY GRIFFITH: The study appeared in the journal Nature Geoscience. It showed that some of the seeps are freeing ancient methane. The source may be natural gas or coal deposits beneath the lakes.

Other seeps release more recently formed gas. The newer methane may have formed when plant material in the lakes broke down into basic elements. 

Another scientist involved in methane research described the Arctic area as the fastest-warming area on Earth. Euan Nisbet from the University of London said the area has many methane sources that will increase as the temperature rises. He says there is a serious concern that the warming could cause more warming.

Some scientists believe the effects of the freeing of methane will not be seen for many years. Others note that the possibility of a fast methane release could speed up rising temperatures on Earth. 

(MUSIC)

BOB DOUGHTY: An American program called the President’s Emergency Plan for AIDS Relief helps millions of people infected with HIV, the virus responsible for AIDS. PEPFAR is considered one of the most successful programs created during the presidency⁸ of George W. Bush. Its goal was to change HIV/AIDS from a death sentence to a disease that, while serious, could be treated. And for millions of people around the world, that is just what happened.

But researchers say it was not until PEPFAR started using generic drugs that major progress was made in fighting HIV/AIDS. Generic drugs are copies of medicines developed by large drug companies. But they often cost a lot less.

SHIRLEY GRIFFITH: Researchers from Brown University in Rhode Island studied the effectiveness of PEPFAR. Kartik Venkatesh was the lead author of a report on the study. He says the high cost of patented antiretroviral drugs had an immediate⁹ influence on the program after it began.

American officials considered whether to provide patented drugs to HIV-infected patients, both in the United States and overseas. Dr. Venkatesh says some people believe that the drug industry wanted the government-financed program to use patented drugs.

But generic drugs were shown to be effective in treating HIV as far back as two thousand three. Using generic drugs helped cut the cost of treating a person from about one thousand one hundred dollars a year to about three hundred dollars a year in two thousand five.

BOB DOUGHTY: PEPFAR has also been able to save millions of dollars by reducing transportation costs -- for example, using ships instead of airplanes to move the drugs. Dr. Venkatesh says the PEPFAR model could be used in the fight against other diseases as developing countries begin seeing health problems that until recently had only been seen in richer countries.

DR. KARTIK VENKATESH: “There is a movement towards understanding that the real and perhaps potentially larger burden in the future is also going to be chronic¹⁰ diseases like cardiovascular disease, diabetes¹¹ (and) cancer. And those are also diseases that require chronic, long-term medication. A lot can be learned from the experience about accessing generics¹² for the treatment of HIV.”

The Brown University researchers have proposed creation of a plan for what they call the “efficient and transparent” purchase of generic drugs. Planners would include the United States, the World Health Organization and the makers¹³ of generic drugs.

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SHIRLEY GRIFFITH: The search for an effective vaccine against HIV has been called one of the greatest scientific challenges of our time. For the past eleven years, the Vaccine Research Center at America’s National Institutes of Health has been taking part in the search. There have been many successes and failures. But the scientists working at the center are more hopeful than ever they will develop a vaccine.

Guy Jenkins-Bass has been infected with HIV for more than ten years. Like millions of HIV-positive people, anti-retroviral drugs have given him the freedom to live a normal life. He is thankful for the care he receives at the Whitman Walker Clinic in Washington, DC. He hopes that one day there will be a vaccine to prevent HIV infection, and maybe even a cure.

GUY JENKINS-BASS: “I would love to see a cure for it. That would be even better. But it’s not like they’re not trying -- I mean I know people are trying to find a cure.”

BOB DOUGHTY: Gary Nabel has spent more than ten years working to develop a vaccine at the Vaccine Research Center. He says when he started, it seemed like a never-ending project. But he is pleased with the developments of the past few years.

DR. GARY NABEL: “I would have to say from my own personal experience, the high point was probably our ability to identify one of the most broadly-neutralizing antibodies that we’ve yet discovered against HIV.”

Broadly-neutralizing antibodies defend cells in the body from attackers like HIV. The discovery of how they can control the virus has opened up a new way of thinking.

DR. GARY NABEL: “And so there’s a whole parallel approach now where we can begin to engineer these antibodies so that we can give them as infusions¹⁴ into people who may be at high risk to block the infection.”

SHIRLEY GRIFFITH: The Vaccine Research Center has begun testing different antibodies in monkeys. The antibody is given to uninfected monkeys. Then, the animals are left exposed to a level of virus that would normally infect them.

DR. GARY NABEL: “Several of them look very, very promising¹⁵. They’re inhibiting¹⁶, they’re blocking infection. They’re blocking them at relatively¹⁷ low doses.”

Dr. Nabel and his team are preparing to launch human tests early next year.

DR. GARY NABEL: “If we can do these trials and show that the antibodies block infection in people, it essentially¹⁸ validates¹⁹ the target of those antibodies for vaccines²⁰. It also gives us information about -- quantitative²¹ information -- if we’re able to block, what levels of antibodies do we need to achieve in order to prevent it (HIV)?”

Dr. Nabel says even if the tests are successful, there is still more work to be done before a vaccine can be developed.

(MUSIC)

BOB DOUGHTY: This SCIENCE IN THE NEWS was written by Christopher Cruise and Jerilyn Watson. Our producer was June Simms. I’m Bob Doughty.

SHIRLEY GRIFFITH: And I’m Shirley Griffith. Join us again next week for more news about science in Special English on the Voice of America.

1 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

2 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

3 generic   

adj.一般的，普通的，共有的

参考例句：

• I usually buy generic clothes instead of name brands.我通常买普通的衣服，不买名牌。
• The generic woman appears to have an extraordinary faculty for swallowing the individual.一般妇女在婚后似乎有特别突出的抑制个性的能力。

4 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

5 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

6 sediments   

沉淀物( sediment的名词复数 )； 沉积物

参考例句：

• When deposited, 70-80% of the volume of muddy sediments may be water. 泥质沉积物沉积后，体积的70-80％是水。
• Oligocene erosion had truncated the sediments draped over the dome. 覆盖于穹丘上的沉积岩为渐新世侵蚀所截削。

7 seeps   

n.（液体）渗( seep的名词复数 )；渗透；渗出；漏出v.（液体）渗( seep的第三人称单数 )；渗透；渗出；漏出

参考例句：

• Water seeps through sand. 水渗入沙中。 来自《现代汉英综合大词典》
• Water seeps out of the wall. 水从墙里沁出。 来自《现代汉英综合大词典》

8 presidency   

n.总统(校长，总经理)的职位(任期)

参考例句：

• Roosevelt was elected four times to the presidency of the United States.罗斯福连续当选四届美国总统。
• Two candidates are emerging as contestants for the presidency.两位候选人最终成为总统职位竞争者。

9 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。

10 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

11 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

12 generics   

n.（产品，尤指药物 ）无厂家商标的，无商标的( generic的名词复数 )

参考例句：

• Pfizer has set up an in-house division to handle such generics. Pfizer已经建立了一个内部机构来处理这些学名药。 来自互联网
• Payers are being more pushy about getting patients to take generics. 药物费用的支付者更倾向于让病人使用非专利药。 来自互联网

13 makers   

n.制造者，制造商（maker的复数形式）

参考例句：

• The makers of the product assured us that there had been no sacrifice of quality. 这一产品的制造商向我们保证说他们没有牺牲质量。
• The makers are about to launch out a new product. 制造商们马上要生产一种新产品。 来自《简明英汉词典》

14 infusions   

n.沏或泡成的浸液（如茶等）( infusion的名词复数 )；注入，注入物

参考例句：

• Intravenous infusions are also used to administer medications. 静脉输液也可作为一种给药方法。 来自辞典例句
• INTERPRETATION: GKI infusions significantly reduced plasma glucose concentrations and blood pressure. 结论：静脉滴注GKI显著降低血压和血糖浓度。 来自互联网

15 promising   

adj.有希望的，有前途的

参考例句：

• The results of the experiments are very promising.实验的结果充满了希望。
• We're trying to bring along one or two promising young swimmers.我们正设法培养出一两名有前途的年轻游泳选手。

16 inhibiting   

抑制作用的，约束的

参考例句：

• The high cost of borrowing is inhibiting investment by industry in new equipment. 借款的高成本抑制了企业对新设备的投资。
• The pesticides affect the nervous system by inhibiting the enzyme cholinesterase. 这类农药抑制胆碱酯酶而影响神经系统。

17 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

18 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

19 validates   

v.证实( validate的第三人称单数 )；确证；使生效；使有法律效力

参考例句：

• Other research validates that when it comes to chocolate, type does matter. 其他的研究也证实了不同种类的巧克力确实功效不同。 来自互联网
• Trouble shoots equipment, review and validates data and complete reports. 管理错误描述设备，审查并确认试验数据，完成试验报告。 来自互联网

20 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

21 quantitative   

adj.数量的，定量的

参考例句：

• He said it was only a quantitative difference.他说这仅仅是数量上的差别。
• We need to do some quantitative analysis of the drugs.我们对药物要进行定量分析。