Ｎｅｗｔｓ?。遥澹纾颍铮鳌。蹋椋恚猓?/h1>
2008-04-01 02:40:10
中學(xué)科技 2008年3期
Translation
Whenpeopleloselegs afteraccidents orillnesses, emergency care and artificial limbs often allow them to walk again. But newts in the same situation don't need doctors or artificial body parts. They can grow limbs back on their own.
A team of British scientists started their study with two simple observations: When you cut off a newt's leg at the ankle, only the foot grows back. If you cut off a leg at the base, the whole leg grows back. In both cases, the regrowth begins with stem cells.
But how do a newt's stem cells know when to regrow only a foot and when to regrow an entire leg? This question relates to another mystery: In newts, a severed leg will grow back only if the bundle of nerves in it also grows back. But if something prevents the nerve bundle from growing, the stem cells atthe siteof the wound won't multiply to produce a new leg.
In their study, the scientists zeroed in on a protein called nAG. When the team prevented nerves in a limb from growing, but added the nAG protein to stem cells in the limb, the limb still regrew.
The scientists suspect that nerves in the stub of a limb signal the release of the nAG protein. That protein seems to guide limb regrowth.
Peopleandothermammalshaveproteinsthatare similar to nAG. Further research into these compounds may someday help human limbs and organs heal themselves.
蠑螈重新長肢
當(dāng)人們由于事故或疾病失去腿時，急診加假肢常常能使他們重新行走。但蠑螈在同樣的情況下卻不需要醫(yī)生或是假肢，它們自己會重新長出肢體。
一組英國科學(xué)家是從兩個簡單的觀察結(jié)果開始他們對這問題的研究的：你如果在踝關(guān)節(jié)處切斷蠑螈的腿，重新長出來的只是腳；而如果你把蠑螈的腿從根部切斷，就會長出一整條腿。在以上兩種情況下，重新生長的過程都是從干細胞開始的。
但是蠑螈的干細胞怎么知道什么時候只要重新長一只腳，什么時候要重新長一整條腿呢？這個問題牽涉到另一個謎：在蠑螈身上，受到重傷的腿只有在腿里的神經(jīng)束也在重新生長的情況下才會重新生長。但如果有什么東西阻礙神經(jīng)束生長，傷口處的干細胞就不會繁殖，因而長不出新腿。
科學(xué)家們在研究時把他們的注意力集中在一種叫做nAG的蛋白質(zhì)上。當(dāng)他們設(shè)法阻止肢體里的神經(jīng)生長，但同時又把nAG蛋白質(zhì)加進肢體的干細胞中時，這個肢體仍然會重新長出來。
科學(xué)家們猜想，肢體殘余部分里的神經(jīng)發(fā)出釋放nAG蛋白質(zhì)的信號，看來正是釋放出來的這種蛋白質(zhì)導(dǎo)致了肢體的重新生長。
人類和其他哺乳動物也有類似于nAG的蛋白質(zhì)。對這種化合物做進一步研究有可能有朝一日能幫助人類肢體和器官自我療傷。
（注意斜體部分的譯法）
ListeningDevice Provides LandslideEarlyWarning
A device that provides early warning of a landslide by monitoring vibrations in soil is being tested by UK researchers. The (A) d________could save thousands of lives each year by warning when an area should be evacuated. Such natural disasters are (1) c_________in countries that experience sudden, heavy rainfall, and can also be triggered by earthquakes and even water (2) e______.
The most common way to monitor a slope for signs of an imminent (B) l________is to watch for changes in its shape. Surveyors can do this by measuring a site directly, or sensors sunk into boreholes or fixed above ground can be used to (C) m________the shape of aslope. Slopescan, however, changeshape without triggering a landslide, so either method is prone to causing false alarms. Now scientists have developed a device that listens for the vibrations caused when particles begin(3) m_________within a slope.
The device takes the form of a steel pipe dropped into a borehole in a slope. The borehole is filled in with gravel around the pipe to help(4) t________high-frequency vibrations generated by particles within the slope. These vibrations pass up the tube and are picked up by a sensor on the surface. Software analyses the (5) v_________signal to determine whether a landslide may be imminent.
The device iscurrentlybeingtestedina6-metre-tallartificial clay embankment in Newcastle, UK. Once it has been carefully and thoroughly tested, the device could be used to create a complete early-warning (6) s________fordangerous slopes. Locationswith asignificant risk oflandslides could definitely (D) b________from a machine like this. (A,B,C,D FOR CROSS, 1,2,3,4,5,6 FOR DOWN. The first letters of the absents were given)
Lucas'Puzzle
Leaving now the questions of formal geometrical propositions, I proceed to enumerate a few games or puzzles which depend mainly on the relative position of things. Some writers regard draughts, solitaire, chess, and such like games as subjects for geometrical treatment in the same way as they treat dominoes, backgammon, and games with dice in connection with arithmetic: but these discussions require too many artificial assumptions to correspond with the games as actually played or to be interesting.
The amusements to which I refer are of a more trivial description, in some cases it is difficult to say whether they should be classified as mainly arithmetical or geometrical, but the point is of no importance.
A problem with pawns (this problem was invented by the famous French mathematician Lucas) : on a row of seven squares on a chess-board, 3 white pawns (or counters) are placed on the 3 squares at one end, and 3 black pawns (or counters) are placed on the 3 squares attheotherend - themiddlesquare being left vacant. Each piece can move only in one direction; the white pieces can move from left to right, and the black pieces from right to left. If the square next to a piece is unoccupied, it can move on to that; or if the square beyond that is occupied by a piece of the opposite colour and the square next to it is unoccupied, then it can leap over that piece on to the unoccupied square beyond it. The object is to get all the white pawns in the places occupied initially by the black pawns and vice versa.
上期Read&
Comprehension答案
1. A 2. C
3. C 4. B
上期Crossword答案
A. controlB. scientists
C. better D. cloud
E. severeF. century
1. level 2. worst
3. treatment 4. greenhouse
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Translation
Whenpeopleloselegs afteraccidents orillnesses, emergency care and artificial limbs often allow them to walk again. But newts in the same situation don't need doctors or artificial body parts. They can grow limbs back on their own.
A team of British scientists started their study with two simple observations: When you cut off a newt's leg at the ankle, only the foot grows back. If you cut off a leg at the base, the whole leg grows back. In both cases, the regrowth begins with stem cells.
But how do a newt's stem cells know when to regrow only a foot and when to regrow an entire leg? This question relates to another mystery: In newts, a severed leg will grow back only if the bundle of nerves in it also grows back. But if something prevents the nerve bundle from growing, the stem cells atthe siteof the wound won't multiply to produce a new leg.
In their study, the scientists zeroed in on a protein called nAG. When the team prevented nerves in a limb from growing, but added the nAG protein to stem cells in the limb, the limb still regrew.
The scientists suspect that nerves in the stub of a limb signal the release of the nAG protein. That protein seems to guide limb regrowth.
Peopleandothermammalshaveproteinsthatare similar to nAG. Further research into these compounds may someday help human limbs and organs heal themselves.
蠑螈重新長肢
當(dāng)人們由于事故或疾病失去腿時，急診加假肢常常能使他們重新行走。但蠑螈在同樣的情況下卻不需要醫(yī)生或是假肢，它們自己會重新長出肢體。
一組英國科學(xué)家是從兩個簡單的觀察結(jié)果開始他們對這問題的研究的：你如果在踝關(guān)節(jié)處切斷蠑螈的腿，重新長出來的只是腳；而如果你把蠑螈的腿從根部切斷，就會長出一整條腿。在以上兩種情況下，重新生長的過程都是從干細胞開始的。
但是蠑螈的干細胞怎么知道什么時候只要重新長一只腳，什么時候要重新長一整條腿呢？這個問題牽涉到另一個謎：在蠑螈身上，受到重傷的腿只有在腿里的神經(jīng)束也在重新生長的情況下才會重新生長。但如果有什么東西阻礙神經(jīng)束生長，傷口處的干細胞就不會繁殖，因而長不出新腿。
科學(xué)家們在研究時把他們的注意力集中在一種叫做nAG的蛋白質(zhì)上。當(dāng)他們設(shè)法阻止肢體里的神經(jīng)生長，但同時又把nAG蛋白質(zhì)加進肢體的干細胞中時，這個肢體仍然會重新長出來。
科學(xué)家們猜想，肢體殘余部分里的神經(jīng)發(fā)出釋放nAG蛋白質(zhì)的信號，看來正是釋放出來的這種蛋白質(zhì)導(dǎo)致了肢體的重新生長。
人類和其他哺乳動物也有類似于nAG的蛋白質(zhì)。對這種化合物做進一步研究有可能有朝一日能幫助人類肢體和器官自我療傷。
（注意斜體部分的譯法）
ListeningDevice Provides LandslideEarlyWarning
A device that provides early warning of a landslide by monitoring vibrations in soil is being tested by UK researchers. The (A) d________could save thousands of lives each year by warning when an area should be evacuated. Such natural disasters are (1) c_________in countries that experience sudden, heavy rainfall, and can also be triggered by earthquakes and even water (2) e______.
The most common way to monitor a slope for signs of an imminent (B) l________is to watch for changes in its shape. Surveyors can do this by measuring a site directly, or sensors sunk into boreholes or fixed above ground can be used to (C) m________the shape of aslope. Slopescan, however, changeshape without triggering a landslide, so either method is prone to causing false alarms. Now scientists have developed a device that listens for the vibrations caused when particles begin(3) m_________within a slope.
The device takes the form of a steel pipe dropped into a borehole in a slope. The borehole is filled in with gravel around the pipe to help(4) t________high-frequency vibrations generated by particles within the slope. These vibrations pass up the tube and are picked up by a sensor on the surface. Software analyses the (5) v_________signal to determine whether a landslide may be imminent.
The device iscurrentlybeingtestedina6-metre-tallartificial clay embankment in Newcastle, UK. Once it has been carefully and thoroughly tested, the device could be used to create a complete early-warning (6) s________fordangerous slopes. Locationswith asignificant risk oflandslides could definitely (D) b________from a machine like this. (A,B,C,D FOR CROSS, 1,2,3,4,5,6 FOR DOWN. The first letters of the absents were given)
Lucas'Puzzle
Leaving now the questions of formal geometrical propositions, I proceed to enumerate a few games or puzzles which depend mainly on the relative position of things. Some writers regard draughts, solitaire, chess, and such like games as subjects for geometrical treatment in the same way as they treat dominoes, backgammon, and games with dice in connection with arithmetic: but these discussions require too many artificial assumptions to correspond with the games as actually played or to be interesting.
The amusements to which I refer are of a more trivial description, in some cases it is difficult to say whether they should be classified as mainly arithmetical or geometrical, but the point is of no importance.
A problem with pawns (this problem was invented by the famous French mathematician Lucas) : on a row of seven squares on a chess-board, 3 white pawns (or counters) are placed on the 3 squares at one end, and 3 black pawns (or counters) are placed on the 3 squares attheotherend - themiddlesquare being left vacant. Each piece can move only in one direction; the white pieces can move from left to right, and the black pieces from right to left. If the square next to a piece is unoccupied, it can move on to that; or if the square beyond that is occupied by a piece of the opposite colour and the square next to it is unoccupied, then it can leap over that piece on to the unoccupied square beyond it. The object is to get all the white pawns in the places occupied initially by the black pawns and vice versa.
上期Read&
Comprehension答案
1. A 2. C
3. C 4. B
上期Crossword答案
A. controlB. scientists
C. better D. cloud
E. severeF. century
1. level 2. worst
3. treatment 4. greenhouse
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