All animals produce waste. We call it "waste," but we all know it can be very useful. In some parts of the world, animal waste, or poop, is collected, dried, and burned for cooking and heating. {#blank#}1{#/blank#} 

    The Chengdu Giant Panda Breeding Center has an unusual way of using animal "waste." The center's 40 pandas produce about two tons of poop a day. This material is being turned into a new product called Panda Poop Paper. {#blank#}2{#/blank#} After all, paper is made from plant fiber, which cannot be digested and simply goes through the body as waste.

    Since pandas eat nothing but bamboo, their "waste" is perfect paper material. {#blank#}3{#/blank#} 

    Their stomachs haven't fully developed for their vegetarian diet, so their bodies make use of just 20% of what they eat. The other 80% comes out as poop: very high in fiber and perfect for paper.

    Once the poop is collected, it is cleaned with chemicals, crushed(碾碎), and put into frames(框架) to dry. {#blank#}4{#/blank#} Because of its good quality as well as the worldwide popularity of the panda, gift products made from the paper sell well.

    {#blank#}5{#/blank#} They got the idea from the elephant dung(大象粪) paper made at Elephant Conservation Center in Chiang Mai, Thailand. And Creative Paper Wales in the U.K. sell paper gifts made from sheep waste.

A. But do you know some paper from poop?

B. Where does the paper come from?

C. After these steps, good, strong paper comes into being.

D. Moreover, there is more special about pandas.

E. It's not really that strange!

F. Yet, the Chinese weren't the first people producing paper from animal waste.

G. Farmers have been using animal and human waste for a long time.

    For centuries, medical pioneers have refined a variety of methods and medicines to treat sickness, injury, and disability, enabling people to live longer and healthier lives.

    “A salamander (a small lizard-like animal) can grow back its leg. Why can't a human do the same?” asked Peruvian-born surgeon Dr. Anthony Atala in a recent interview. The question, a reference to work aiming to grow new limbs for wounded soldiers, captures the inventive spirit of regenerative medicine. This innovative field seeks to provide patients with replacement body parts.

These parts are not made of steel; they are the real things — living cells, tissue, and even organs.

    Regenerative medicine is still mostly experimental, with clinical applications limited to procedures such as growing sheets of skin on burns and wounds. One of its most significant advances took place in 1999，when a research group at North Carolina's Wake Forest Institute for Regenerative Medicine conducted a successful organ replacement with a laboratory-grown bladder. Since then, the team, led by Dr. Atala, has continued to generate a variety of other tissues and organs—from kidneys to ears.

    The field of regenerative medicine builds on work conducted in the early twentieth century with the first successful transplants of donated human soft tissue and bone. However, donor organs are not always the best option. First of all, they are in short supply, and many people die while waiting for an available organ; in the United States alone, more than 100,000 people are waiting for organ transplants. Secondly, a patient's body may ultimately reject the transplanted donor organ. An advantage of regenerative medicine is that the tissues are grown from a patient's own cells and will not be rejected by the body's immune system.

    Today, several labs are working to create bioartificial body parts. Scientists at Columbia and Yale Universities have grown a jawbone and a lung. At the University of Minnesota, Doris Taylor has created a beating bioartificial rat heart. Dr. Atala's medical team has reported long-term success with bioengineered bladders implanted into young patients with spina bifida (a birth defect that involves the incomplete development of the spinal cord). And at the University of Michigan, H. David Humes has created an artificial kidney.

    So far, the kidney procedure has only been used successfully with sheep, but there is hope that one day similar kidney will be implantable in a human patient. The continuing research of scientists such as these may eventually make donor organs unnecessary and, as a result, significantly increase individuals' chances of survival.

    Let's face it. No one drinks diet sodas for the taste. People drink diet sodas in the hope that it will help them lose weight or at least keep them from gaining it. Yet it seems to have exactly the opposite effect, according to a new study.

    Researchers from the University of Texas said those who drank two or more diet sodas a day had waist size increases that were six times greater than those who didn't drink diet sodas. "What we saw was that the more diet sodas a person drank, the more weight they were likely to gain," said Sharon Fowler.

    The study was based on data from 474 participants in a large, ongoing research project, where the participants were followed for nearly 10 years.

    While the findings are surprising, they also offer some explanations.

    Nutrition expert, Melanie Rogers, who works with overweight patients in New York, has found that when patients are switched from regular to diet sodas, they don't lose weight at all. "We weren't seeing weight loss necessarily, and that was confusing to us," said Rogers.

    So why would diet soda cause weight gain? No one knows for sure yet, but it could be that people think they can eat more if they drink diet sodas, and so over-compensate(补偿) for the missing calories.

    A related study found some sweeteners (甜味剂) raised blood sugar levels in some mice. "Data from this and other potential studies suggest that the promotion of diet sodas and artificial sweeteners may be risky," said Helen P. Hazuda, professor at the University of Texas's school of medicine. "They may be free of calories, but not of consequences."

    Being crazy about perfection(完美) among young people has risen by more than 30 per-cent over the last three decades, a study has found.

    Many of them believe that their environment is very demanding and that others judge them strictly, according to analysis of data from more than 40,000 British, Canadian and American university students from 1989 t0 2018.

    The research, carried out by the University of Bath and York St John University, found that the extent to which young people attach an irrational importance on being perfect, hold unrealistic expectations of themselves and are highly self-critical has increased by 10 percent when compared to previous generations. The authors suggested their findings point to the impact of three decades of neoliberalism (新自由主义) forcing young people to compete against one another.

    Lead author Dr Thomas Curran from the University of Bath's Department for Health said he hoped organizations responsible for guarding the welfare of young people, such as schools, universities, and policymakers who shape the environments in which these organizations operate, would resist the promotion of competitiveness at the expense of young people's psycho-logical health.

    He said, "Rising rates of perfectionism highlighted in this study correspond to three decades of neoliberalism, which has forced young people to compete against each other in an in-creasingly demanding social and economic environment." The study also found the extent to which young people impose (迫使) unrealistic standards on those around them and evaluate others critically has increased by 16 percent.

    The researches defined perfectionism as a combination of extremely high personal standards and overly harsh self-criticism, leading to psychological difficulties.

    Co-author Dr Andrew Hill of York St John University added, "The increase in mental health difficulties among young people makes for a setting for our findings. The higher level of perfectionism may be a key contributing factor to such difficulties. Young people are trying to find ways to cope with increasing demands being placed on them and they are responding by becoming more perfect towards themselves and others."

    Like infectious diseases, ideas in the academic world are epidemic (传染的). But why some travel far and wide while equally good ones has been a mystery? Now a team of computer scientists has used an epidemiological model to simulate (模仿) how ideas move from one academic institution to another. The model showed that ideas originating at famous institutions caused bigger "epidemics" than equally good ideas from less famous places, explains Allison Morgan, a computer scientist at the University of Colorado Boulder.

    "This implies that where an idea is born shapes how far it spreads," says senior author Aaron Clauset.

    Not only is this unfair— "it reveals a big weakness in how we're doing science," says Simon DeDeo, a professor of social and decision sciences at Carnegie Mellon university, who was not involved in the study. "There are many highly trained people with good ideas who do not end up at top institutions. They are producing good ideas, and we know those ideas are getting lost," DeDeo says. "Our science, our scholarships, is not as good because of this."

    The Colorado researchers first looked at how five big ideas in computer science spread to new institutions. They found that hiring a new faculty member accounted for this movement a little more than a third of the time--and in 81 percent of those cases, transmissions took place from higher – to lower-prestige (声望) universities. Then the team simulated the spread of ideas using an infectious disease model and found that the size of an idea "epidemic" depended on the prestige of the originating institution.

    The researchers' model suggests that there "may be a number of quite good ideas that originate in the middle of the pack, in terms of universities." Clauset says. There is a lot of good work coming out of less famous places, he says: "You can learn a huge amount from it, and you can learn things that other people don't know because they're not even paying attention."

Mark and his brother Jason both were looking at the shining new computer enviously. Jason was determined not to go against their father's wishes but Mark was more adventurous than his brother. He loved experimenting and his aim was to become a scientist like his father.

"Dad will be really mad if he finds out you've been playing with his new computer." said, "He told us not to touch it."

"He won't find out," Mark said, "I'll just have a quick look and shut it down."

Mark had been scolded before for touching his father's equipment. But his curiosity was difficult to control and this new computer really puzzled him.

It was a strange-looking machine — one his dad had brought home from the laboratory where he worked. "It's an experimental model." his father had explained, "so don't touch it under any circumstances." But his father's warning only served to make Mark more curious. Without any further thought, Mark turned on the power switch. The computer burst into life and seconds later the screen turned into colours, shifting and changing, and then two big white words appeared in the centre of the screen: "SPACE TRANSPORTER."

"Yes!" Mark cried excitedly. "It's a computer game. I knew it! Dad's only been pretending to work. He's really been playing games instead!" A new message appeared on the screen:

"ENTER NAMES

VOYAGER 1:…

VOYAGER 2:…

Mark's fingers flew across the keyboard as he typed in both of their names.

"INPUT ACCEPTED. START TRANSPORT PROGRAM. AUTO-RETRIEVE INITIATED. "

The screen turned even brighter and a noise suddenly rose in volume.

"I think we'd better shut it off, Mark," Jason yelled, reaching for the power switch. He was really frightened.

But his hand never reached the switch. A single beam of dazzling white light burst out of the computer screen, wrapping the boys in its glow, until they themselves seemed to be glowing. Then it died down just as suddenly as it had burst into life. And the boys were no longer there. On the screen, the letters changed:

"TRANSPORT SUCCESSFUL. DESTINATION: MARS. RETRIEVE DATE: 2025."