"Life Form Found" on Saturn"s Titan

Scientists say they have discovered hints of alien life1 on the Saturn"s moon2. The discovery of a sort of life was announced after researchers at the US space agency,NASA3,analyzed data from spacecraft Cassini4,which pointed to,the existence of methane-based form of life on Saturn"s biggest moon.

Scientists have reportedly discovered clues showing primitive alien beings are"breathing" in

Titan"s dense atmosphere filled with hydrogen.

They argue that hydrogen gets absorbed before hitting Titan"s planet-like surface covered with methane lakes and rivers. This,they say,points to the existence of some"bugs"5 consuming the hydrogen at the surface of the moon less than half the size of the Earth.

"We suggested hydrogen consumption because it"s the obvious gas for life to consume on Titan,similar to the way we consume oxygen on Earth,"says NASA scientist Chris McKay."If these signs do turn out to be a sign of life,it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."

To date,scientists have not yet detected this form of life anywhere,though there are liquid-

water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin6(minus 290 degrees Farenheit),a methanebased organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan"s surface and much too cold to support life as we know it.

Scientists had expected the Sun"s interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan"s surface. But Cassini detected no acetylene on the surface.

The absence of detectable acetylene on the Titan"s surface can very well have a non-biological explanation,said Mark Allen,a principal investigator7 of the NASA Titan team.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed,"Allen said. "We have a lot of work to do to rule out8 possible non-biological explanations. It is more likely that a chemical process,without biology,can explain these results."

词汇：

Saturn /"sætən/ n．土星        

methane/"mi:θein/ n．甲烷，沼气

Titan/"taitən/ n．土卫六       

acetylene/ə"setili:n/ n．乙炔

alien/"eiljən/ n．外星人；adj．外星球的；相异的 

conservatism/kən"sʒ:vətizəm/ n．保守主义,守旧

注释：

1.hints of alien life：外星生命迹象。

2.the Saturn"s moon：指土卫六（Titan) 。土卫六又称泰坦星，是土星卫星中最大的一颗。

3.NASA：美国国家航空航天局的缩写，全称是： National Aeronautics and Space

Administration。

4.spacecraft Cassini：卡西尼号探测器，以出生于意大利的法国天文学家卡西尼的名字命名，其任务是环绕土星飞行，对土星及其大气、光环、卫星和磁场进行深人考察。1997 年10 月15日，重六吨的“卡西尼”号星际探测器被发射飞往土星的轨道。这是上世纪发射的最后一艘行星际探测的大飞船。“卡西尼”号用了将近七年时间，在2004 年7月1日飞达土星轨道。

5.bugs：微生物。非正式口语表达，所以使用了引号。

6.Kelvin：可翻译成“绝对温度”。Kelvin Scale ，绝对温标，开氏温标，是由Kelvin 勋爵于19世纪中叶发明的温度计量方法，其零度相当于摄氏一273. 15" C ，被认为是宇宙中最低温度。这种温度计量方法多为科学家使用。

7.principal investigator：研究项目负责人

8.rule out：排除……的可能性

What have scientists found about Saturn?

A:They have found a new moon orbiting Saturn. B:They have found methane-based life on Saturn. C:They have found methane-based life on Titan. D:They have found earthlike life on a Saturn"s moon.

In the angry debate over how much of IQ comes from the genes that children inherit from parents and how much comes from experiences, one little fact gets overlooked: no one has identified any genes (other than those that cause retardation) that affect intelligence. So researchers led by Robert Plomin of London’s Institute of Psychiatry decided to look for some:
Plomin’s colleagues drew blood from two groups of 51 children each. They are all White living in six counties around Cleveland. In one group, the average IQ is 136. In the other group, the average IQ is 103. Isolating the blood cells, the researchers then examined each child’s chromosome 6 (One of the 23 human chromosomes). Of the 37 land marks on chromosome 6that the researchers looked for, one jumped out: a form of gene called IGF2R occurred in twice as many children in high IQ group as in the average grouw-32 percent versus 16 percent. The study concludes that it is this form of the IGF2R gene, called allele 5, that contributes to intelligence.
Plomin cautions that "This is not a genius gene. It is one of many." (About half the differences in intelligence between one person and another are thought to reflect different genes, and half reflect different life experiences.)The gene accounts for no more than four extra IQ points. And it is neither necessary nor sufficient for high IQ: 23 percent of the average-IQ kids did have it, but 54 percent of genius kids did not.
The smart gene is known by the snappy name "insulin like growth factor 2 receptor" (IGH2R to its fun). It lets hormones like one similar to insulin dock with cells. Although a gene involved with insulin is not the most obvious candidate for an IQ gene, new evidence suggests it might indeed play the role. Sometimes when s hormone docks with the cell, it makes the cell grow; sometimes it makes the cell commit suicide. Both responses could choreograph the development of the brain. Scientists at the National Institutes of Health find that insulin can stimulate nerves to grow. And in rat brains, regions involved in learning and memory are chock full of insulin receptors.
Even though this supports the idea that IGF2R can affect the brain and hence intelligence, some geneticists see major problems with the IQ-gene study. One is the possibility that Plomin’s group fell for what’s called the chopsticks fallacy. Geneticists might think they’ve found a gene for chopsticks dexterity, but all they’ve really found is a gene more common in Asians than, say, Africans. Similarly, Plomin’s IQ gene might simply be one that is more common in groups that emphasize academic achievement. "What if the gene they’ve found reflects ethnicity" asks geneticist Andrew Feinberg of Johns Hopkins University. "I would take these findings with a whole box of salt./
As for how much of IQ comes from the genes and how much come from experiences,______.

A:scientists have reached an agreement B:scientists’ opinions vary C:no genes have ever been identified D:scientists have found many smart genes

Text 3
In the angry debate over how much of IQ comes from the genes that children inherit from parents and how much comes from experiences, one little fact gets overlooked: no one has identified any genes (other than those in the case of retardation) that affect intelligence. So researchers led by Robert Plomin of London’s Institute of Psychiatry decided to look for some.
Plomin’s colleagues drew blood from two groups of 51 children each. They are all White living in six counties around Cleveland. In one group, the average IQ is 136. In the other group, the average IQ is 103. Isolating the blood cells, the researchers then examined each child’s chromosome 6 ( One of 23 human chromosomes along which genes made of DNA). Of the 37 landmarks on chromo- some 6 that the researchers looked for, one jumped out: a form of gene called IGF2R occurred in twice as many children in high-IQ group as in the average group -- 32 percent versus 16 percent. The survey concludes that it is this form of the IGF2R gene, called allele 5, that contributes to intelligence.
Plomin cautions that "this is not a genius gene. h is one of many." ( About half the differences in intelligence between one person and another are thought to reflect different genes, and half reflect different life experiences. ) The gene accounts for no more than four extra IQ points. And it is neither necessary nor sufficient for high IQ: 23 percent of the average-IQ kids did have it, but 54 percent of genius kids did not.
The smart gene is known by the interesting name "insulinlike growth factor 2 receptor" (IGF2R to its fun). It lets hormones like one similar to insulin dock with cells. Although a gene involved with insulin is not the most obvious candidate for an IQ gene, new evidence suggests it might indeed play the role. Sometimes when a hormone docks with the cell, it makes the cell grow; sometimes it makes the cell commit suicide. Both responses could organize the development of the brain. Scientists at the National Institutes of Health find that insulin can stimulate nerves to grow. And in rat brains, regions involved in learning and memory are chock full of insulin receptors.
Even though this supports the idea that IGF2R can affect the brain and hence intelligence, some geneticists see major problem with the IQ-gene study. One is the possibility that Plomin’s group fell for what’s called the chopsticks fallacy. Geneticists might think they’ve found a gene for chopsticks skill, but all they’ve really found is a gene more common in Asian than, say, Africans. Similarly, Plomin’s IQ gene might simply be one that is more common in groups that emphasize academic achievement. "What if the gene they’ve found reflects ethnic differences" asks geneticist Andrew Feinberg of Johns Hopkins University. "I would take these findings with a whole box of salt."

A:scientists have reached an agreement. B:scientists’ opinions vary. C:no genes have ever been identified. D:scientists have found many smart genes.

In the angry debate over how much of IQ comes from the genes that children inherit from parents and how much comes from experiences, one little fact gets overlooked: no one has identified any genes (other than those that cause retardation) that affect intelligence. So researchers led by Robert Plomin of London’s Institute of Psychiatry decided to look for some:
Plomin’s colleagues drew blood from two groups of 51 children each. They are all White living in six counties around Cleveland. In one group, the average IQ is 136. In the other group, the average IQ is 103. Isolating the blood cells, the researchers then examined each child’s chromosome 6 (One of the 23 human chromosomes). Of the 37 land marks on chromosome 6that the researchers looked for, one jumped out: a form of gene called IGF2R occurred in twice as many children in high IQ group as in the average grouw-32 percent versus 16 percent. The study concludes that it is this form of the IGF2R gene, called allele 5, that contributes to intelligence.
Plomin cautions that "This is not a genius gene. It is one of many." (About half the differences in intelligence between one person and another are thought to reflect different genes, and half reflect different life experiences.)The gene accounts for no more than four extra IQ points. And it is neither necessary nor sufficient for high IQ: 23 percent of the average-IQ kids did have it, but 54 percent of genius kids did not.
The smart gene is known by the snappy name "insulin like growth factor 2 receptor" (IGH2R to its fun). It lets hormones like one similar to insulin dock with cells. Although a gene involved with insulin is not the most obvious candidate for an IQ gene, new evidence suggests it might indeed play the role. Sometimes when s hormone docks with the cell, it makes the cell grow; sometimes it makes the cell commit suicide. Both responses could choreograph the development of the brain. Scientists at the National Institutes of Health find that insulin can stimulate nerves to grow. And in rat brains, regions involved in learning and memory are chock full of insulin receptors.
Even though this supports the idea that IGF2R can affect the brain and hence intelligence, some geneticists see major problems with the IQ-gene study. One is the possibility that Plomin’s group fell for what’s called the chopsticks fallacy. Geneticists might think they’ve found a gene for chopsticks dexterity, but all they’ve really found is a gene more common in Asians than, say, Africans. Similarly, Plomin’s IQ gene might simply be one that is more common in groups that emphasize academic achievement. "What if the gene they’ve found reflects ethnicity" asks geneticist Andrew Feinberg of Johns Hopkins University. "I would take these findings with a whole box of salt."

A:scientists have reached an agreement B:scientists’ opinions vary C:no genes have ever been identified D:scientists have found many smart genes

Only (within) the past 200 years (scientists have) found (out what) fire (is).

A:within B:scientists have C:out what D:is

Only (within) the past 200 years (scientists have) found (out what) fire (is).

A:within B:scientists have C:out what D:is

Only (within) the past 200 years (scientists have) found (out what) fire (is).

A:within B:scientists have C:out what D:is