Recently there was a major discovery in the scientific research—the mapping of all DNA in a human gene(基因) is complete．Couple of years ago, this seems an impossible task for scientist to accomplish．All this progress in science leads us to believe that the day, when the human being will be cloned, is not far away．Human cloning has always been a topic of argument, in terms of morality or religion．

Taking a look at why cloning might be beneficial, among many cases, it is arguable that parents who are known to be at risk of passing a genetic limitation to a child could make use of cloning．If the clone was free of genetic limitations．then the other clone would be as well．The latter could foe inserted in the woman and allowed to ripen to term．Moreover, cloning would enable women, who canˈt get pregnant, to have children of their own．

Cloning humans would also mean that organs could be cloned, so it would be a source of perfect transfer organs．This, surely would be greatly beneficial to millions of unfortunate people around the world that are expected to lose their lives due to failure of single (or more) organ(s). It is also arguable that a ban on cloning may be unlawful and would rob people of the right to reproduce and limit the freedom of scientists．

Arguments against cloning are also on a perfectly practical side．Primarily, I believe that cloning would step in the normal "cycle" of life．There would be a large number of same genes, which reduce the chances of improvement, and, in turn, development—the fundamental reason how living things naturally adapt to the ever-changing environment．Life processes failing to do so might result in untimely disappearance．Furthermore, cloning would make the uniqueness that each one of us possesses disappear．Thus, leading to creation of genetically engineered groups of people for specific purposes and, chances are, that those individuals would be regarded as "objects" rather than people in the society．

Scientists havenˈt 100 percent guaranteed that the first cloned humans will be normal．Thus this could result in introduction of additional limitations in the human "gene-pool"．

Regarding such arguable topics in "black or white" approach seems very innocent to me personally. We should rather try to look at all "shades" of it．I believe that cloning is only legal if its purpose is for cloning organs; not humans．Then we could regard this as for "saving life" instead of "creating life"．I believe cloning humans is morally and socially unacceptable．

At the beginning of this century, medical scientists made an interesting discovery; we are built not just of flesh and blood but also of time. They were  (1)  to show that we all have “a body clock”  (2)  us, which controls the  (3)  and fall of our body energies,  (4)  us different from one day one to the next.

The   (5)  of “a body clock” should not be too  (6)  since the lives of most living things are controlled  (7)   the 24 hour night-and-day cycle. We feel  (8)  and fall asleep at night and become   (9)  and energetic during the day. If the 24 hour-cycle is  (10)  , most people experience unpleasant  (11)   . For example, people who are not  (12)   to working at night can find that  (13)   of sleep causes them to  (14)  badly at work.

  (15)   the daily cycle of sleeping and  (16)  , we also have other cycles which  (17)  longer than one day. Most of us would   (18)  that we feel good on some days and not so good on  (19)   ; sometimes our ideas seem to flow and at other times, they  (20)  ​do not exist.

Preparing Cities for Robot Cars

    The possibility of self﹣driving robot cars has often seemed like a futurist's dream， years away from materializing in the real world． Well， the future is apparently now． The California Department of Motor Vehicles began giving permits in April for companies to test truly self﹣driving cars on public roads． The state also cleared the way for companies to sell or rent out self﹣driving cars， and for companies to operate driverless taxi services． California， it should be noted， isn't leading the way here． Companies have been testing their vehicles in cities across the country． It's hard to predict when  driverless cars will be everywhere on our roads． But however long it takes， the technology has the potential to change our transportation systems and our cities， for better or for worse， depending on how the transformation is regulated．

    While much of the debate so far has been focused on the safety of driverless cars（and rightfully so），policymakers also should be talking about how self﹣driving vehicles can help reduce traffic jams， cut emissions（排放） and offer more convenient， affordable  mobility options． The arrival of driverless vehicles is a chance to make sure that those vehicles are environmentally friendly and more shared．

    Do we want to copy﹣ or even worsen﹣ the traffic of today with driverless cars？ Imagine a future where most adults own individual self﹣driving vehicles． They tolerate long， slow journeys to and from work on packed highways because they can work， entertain themselves or sleep on the ride， which encourages urban spread． They take their driverless car to an appointment and set the empty vehicle to circle the building to avoid paying for parking． Instead of walking a few blocks to pick up a child or the dry cleaning， they send the self﹣driving minibus． The convenience even leads fewer people to take public transport﹣﹣an unwelcome side effect researchers have already found in ride﹣ hailing（叫车） services．

    A study from the University of California at Davis suggested that replacing petrol﹣powered private cars worldwide with electric， self﹣driving and shared systems could reduce carbon emissions from transportation 80% and cut the cost of transportation infrastructure  （基础设施） and operations 40% by 2050． Fewer emissions and cheaper travel sound pretty appealing． The first commercially available driverless cars will almost certainly be fielded by ride﹣hailing services， considering the cost of self﹣driving technology as well as liability and maintenance issues（责任与维护问题）．But driverless car ownership could increase as the prices drop and more people become comfortable with the technology．

    Policymakers should start thinking now about how to make sure the appearance of driverless vehicles doesn't extend the worst aspects of the car﹣controlled transportation system we have today． The coming technological advancement presents a chance for cities and states to develop transportation systems designed to move more people，and more affordably． The car of the future is coming． We just have to plan for it．

There have been claims that warming on Mars(火星) and Pluto(冥王星) is proof that the recent warming on Earth is caused by an increase in solar activity, and not by greenhouse gases. But we can say with certainty that, even if Mars, Pluto or any other planet has warmed in recent years, it is not due to changes in solar activity.

The Sun’s energy output has not increased since direct measurements began in 1978. If increased solar output really was responsible, we should be seeing warming on all the planets and their moons, not just Mars and Pluto.

    Our solar system has eight planets, three dwarf planets and quite a few moons with at least a thin atmosphere, and thus a climate of sorts. Their climates will be affected by local factors such as orbital variations, changes in reflectance and even volcanic eruptions, so it would not be surprising if several planets and moons turn out to be warming at any one time.

    One theory is that winds have recently swept some areas of Mars clean of dust, darkening the surface, warming the Red Planet and leading to further increases in windiness --- a positive feedback effect.

Observations of the thickness of Pluto’s atmosphere in 2002 suggested the dwarf planet was warming even as its orbit took it further from the Sun. The finding confused astronomers at the time, and the cause had yet to be determined.

It has since been suggested that this is due to a greenhouse effect: As it gets closer to the Sun, Pluto may warm enough for some of the methane ice on its surface to turn into a gas. This would cause further warming, which would continue for a while even after Pluto’s orbit starts to take it away from the Sun.

If you need help herding some sheep or retrieving a stick, you can count on your canine companion(伴犬) because dogs always seem to be keen on lending a paw. But only if their partner is a person. When it comes to cooperating with one another, dogs are truly lost－and instead it’s wolves who’ve mastered the art of teamwork. That’s according to a study in the Proceedings of the National Academy of Sciences.

For thousands of years, humans have been breeding (饲养) dogs that can do all sorts of neat tricks. And because dogs aim to please, we’ve come to think that domestication(驯养) has somehow boosted dogs’ powers of cooperation. But researchers in Austria have been wondering whether that idea could be barking up the wrong tree. Because left to their own devices, dogs are bigger loners than wolves.

“So wolves live in closely knit family packs, they cooperate in raising the young, they also cooperate in hunting and in defending their territories. So they really have a strong dependence on cooperation in many aspects of their lives. In contrast, to this free ranging dogs actually forage (觅食) mostly by themselves. It’s only mothers that raise their young. And they do form packs but they tend to be somewhat more fluid(不固定的), if you want.”

That’s Sarah Marshall-Pescini of the Wolf Science Center at the University of Vienna. She and her colleagues decided to test dogs’ and wolves’ relative powers of cooperation. In the setup, a pair of animals—either two dogs or two wolves—is presented with a contraption(装置) that will allow the participants to access a plate of food—but only if both members of the team pull on the two ends of a rope at the same time.

A dozen wolves and 14 dogs took the challenge. And the results? The wolves ran circles around their doggie descendants. In some 400 attempts, the wolf teams scored a snack 100 times. Which may not sound all that impressive…until you compare it with the doggie duos, who, in nearly 500 trials, succeeded only twice.

Now, it’s not that dogs are less avid learners. Or that they turned tail and avoided the apparatus. Marshall-Pescini says the dogs were curious about the device.

“What seemed to be happening was they didn’t want to get into conflict with each other. So they wouldn’t both go and try things on it but rather took it in turns. And this really hindered(阻碍了) their capacity to cooperate.”So rather than step on each others’ toes, the dogs took turns bowing out, giving their teammate a chance at the plate. That show of social grace left the poor dogs with their tummies growling (饥肠辘辘). And no treat to wolf down.

(Source:Scientific American Oct. 25, 2017)

With its incredibly long neck, giraffe looks like no other animal on Earth. But how did this mammal come to get its famously huge neck? Well, scientists have been asking themselves this question for centuries.

The most commonly believed answer is that the massive neck – which measures on average 180 centimeters and weighs about 270 kilograms – evolved to allow the animal to reach the leaves of tall trees. British scientist Charles Darwin was one of the first people to propose this idea in the 1800s.

Yet, there are other theories.

According to a paper published in September in the Journal of Arid Environments, the giraffe’s neck evolved to increase its surface-area-to-volume ratio (表面积—体积比). Because the animal’s neck increases its body’s surface area, it makes it easier for it to keep cool, the paper’s authors wrote.

This phenomenon can be seen everywhere in nature. For example, this is why elephants have such large ears.

Meanwhile, some believe that competition is the answer.

A 1996 study by two South African zoologists argued that the male giraffes with the biggest necks are the ones who “win” access to females to reproduce, as they are better at fighting, meaning that their long necks are passed down through the generations.

So, it seems like there’s still no definite answer to the question.

Special trees that grow faster, fight pollution, produce better wood, and even sense chemical attacks are being planted by scientists in the US.

When 40 percent of Hawaii's US$14 million-a-year papaya (木瓜)industry was destroyed by a virus（病毒）five years ago, work began on creating genetically engineered(转基因的) trees.

Researchers successfully introduced seeds that were designed to resist the virus. Since then, more and more people have been testing genetically engineered trees.Some researchers put special bacteria into trees to help them grow faster and produce better wood. Others are trying to create trees that can clean polluted soil.Meanwhile fruit farmers are looking for trees that are strong enough to resist worms, and paper companies want trees that produce more wood and therefore more paper.

The Pentagon (五角大楼) even gave the researchers US$500,000 this year after they developed a pine tree that changes its colours if it senses a chemical attack..So far,the poplar, eucalyptus (杨树与桉树), apple and coffee trees are among those being engineered. All this can be done today because we have a better understanding of tree genomes(基因组).

However, some people fear that the genetically engineered trees will cause dangerous results. They are worried that the new trees will breed() with natural species and change the balance of the forest environment.

"It could be destructive," said Jim Diamond, an environmentalist. "Trees are what is left of our natural environment and home to many endangered species."

But researchers insist that science could give nature a fighting chance against both natural and man-made dangers.They hope to answer the critics by stopping the new trees from breeding, so their effect on the environment can be controlled.

Multitasking(多任务) affects the brain, research suggests, and it could be damaging your career. A new study found that men and women who frequently used several types of technology at the same time had less grey matter(灰质) in a key part of the brain.

University of Sussex researchers said: “Using mobile phones, laptops and other media devices at the same time could be changing the structure of our brains.” Worryingly, the part of the brain that shrinks is involved in processing emotion. The finding follows research which has linked multitasking with a poor attention, depression, anxiety and lower grades at school.

The researchers began by asking 75 healthy men and women how often they divided their attention between different types of technology. This could mean sending a text message while listening to music and checking emails, or speaking on the phone while watching TV and surfing the web. The volunteers were then given brain scans which showed they had less of grey matter. The study, published in the journal PLOS ONE, is the first to make a link between multitasking and the structure of the brain.

Researcher Kep Kee Loh said: “Media multitasking is becoming more common in our lives today and there is increasing concern about its influences on our cognition(认知) and social-emotional well-being.” He added that more research is needed to prove that multitasking shrinks the brain. This is because it is also possible that people with less grey matter are more drawn to using lots of devices at the same time. Scientists have previously proved brain structure can be changed on long exposure to new environments and experience. Other studies have shown that training---such as learning to juggle or taxi drivers learning the map of London -- can increase grey-matter densities(密度) in certain parts.