Do you ever wonder why trees begin to bud (发芽) earlier in some cities? Scientists finally found the answer but it's not very pleasant. New science suggests a relationship between light pollution and the timing when trees produce buds, which signals the arrival of the spring season.

    Light pollution is defined by the Lighting Research Center as the unwanted consequence of outdoor lighting such as street lights. Excessive (过多的) man-made light at night results in disturbed natural cycles, and also prevents the observation of stars and planets at night. But its effect on the environment goes beyond that.

    By studying some trees, researchers found out that trees that are more exposed to artificial lighting at night bud up to 7.5 days earlier than those at the natural nighttime setting. And they found out that light had a more significant effect than temperature when the buds came out. The early budding may cause problems for insects, which feed on leaves, and the birds which then feed on them in turn. Professor Richard, who helped lead the research, explained that more than the budding of trees, the study implies the danger to the balance of the ecosystem. “At the moment, caterpillars (毛毛虫) are timed to hatch to make the most of the opportunities to feed on freshly budded leaves, and birds hatch in time to feed on the young caterpillar,” he said.

    Migratory (迁徙的) birds are also negatively affected by light pollution. The glare might confuse them and make them lose their flying sense. The phenomenon might explain why some birds accidentally knock into buildings.

    Such results stress the need to pursue studies that aim to measure the effect of light pollution. If the issue were left to continue, it is estimated that by 2100, spring would begin almost a full month earlier than it does today.

    My teacher, Mr. August J. Bachmann, was the most influential teacher I ever had.

    I had gotten into trouble in his class: Another student had pushed me for fun, and I became angry and began to hit him. Mr. Bachmann stopped the fight, but instead of sending me to the office, he sat me down and asked a simple question, "Penna, why are you wasting your life？Why aren't you going to college?"

    I didn't know anything about colleges or scholarships. No one had ever considered that a fatherless boy from the poorest neighborhood had a future. That day, instead of rushing off for lunch, he stayed and explained possible education options to me. At the end of our talk, he sent me to see a secretary who had a child at a state college. This was in 1962 at Emerson High School in Union City, New Jersey.

    Well, 55 years have passed, and what have I done with the knowledge he gave me？I gained a PhD from Fordham University when I was only 29.I taught English and social studies and then moved up the chain of command from teacher to principal(校长).

    I've sat on the board for Magnet Schools of America and represented that organization at the United Nations. I've won a number of great educational awards. But where would I be if a truly caring teacher had not taken the time out of his lunch period to speak to me? It was without question only his confidence in me that helped me forward.

    I have repaid his kindness hundreds of times by encouraging misguided youngsters to aim higher. If I have saved any children, it is because of him. If I have been a successful educator, it is because I had a great role model in Mr. Bachmann.

    Scientists think that growing garden grass could be the secret to solving our energy needs, and we may soon be able to replace our gasoline with "grassoline".

    The team, including experts from Cardiff University in Wales, has shown that hydrogen can be taken from grass in useful amounts with the help of sunlight and a cheap catalyst(催化剂) —something that speeds up a chemical reaction without being used up.

    It is the first time that this has been shown and it could lead to a sustainable(可持续的) way of making hydrogen, reported Asian News International. This could be an important kind of renewable energy because it is high in energy and it does not give out harmful gases when it is burned.

    Study co-author Michael Bowker said, "This is really a green source of energy. Hydrogen is seen as an important future energy carrier as the world moves from fossil fuels to renewable energy, and our research has shown that even garden grass could be a good way of getting it."

    Cellulose(纤维素), which is a key part of plants and the biopolymer(生物聚合物) found in the largest numbers on the earth, could be a great source of hydrogen.

In its study, the team looked at the possibility of getting hydrogen from cellulose using sunlight and a simple catalyst.

    This is called photocatalysis(光催化作用) and in it, the sunlight starts the catalyst, which then makes cellulose and water into hydrogen. The researchers studied the effectiveness of three metal-based catalysts, of which nickel(镍) especially interested the researchers, as it is a much more common metal than gold and palladium(钯) and it saves more money.

    According to Bowker, producing hydrogen from cellulose using photocatalysis has not been studied in detail. The team's research shows that large amounts of hydrogen can be produced using this method with the help of a bit of sunlight and a cheap catalyst.

    The study shows that it is effective to use real grass taken from a garden. "This is important as it avoids the need to separate and clean up cellulose, which can be both difficult and costly," said Bowker.

    It was May 23, 2016. Arnot, the 32-year-old mountain guide, reached the top of Everest without the use of oxygen (O₂) equipment. It was achieved after seven years, three previous attempts, and fourteen straight hours of climbing.

    After 15 minutes at the top, Arnot began her descent (下坡). Eight hours later, she reached the camp at 7, 600 meters and became the first American woman-and only the seventh woman ever—to successfully reach Mount Everest without oxygen equipment.

    "There are so many reasons for her impressive achievement, especially the physical and emotional efforts that she's put forth over the years to make this happen," says the professional climber and photographer Richards, "The mental courage that it requires is something very few people have."

    Arnot didn't start climbing until she was 19 years old. Money was tight in her family, and climbing mountains never occurred in her mind. After graduating from college, Arnot was invited by her friend to climb a mountain. "It totally changed my life, says Arnot. I always know that if you want something, you can achieve it, but knowing what you want is a whole different thing," she says. "I am athletic but not competitive. After my first climbing, I knew immediately that mountains are what I want—as that is where I felt home for the first time in my life."

    After that first climb, she devoted herself to learning how to climb and move through mountain. It was during her second trip to Everest in 2009 that she first set her sights on a no-oxygen attempt. However, while hiking into Everest Base Camp that year, she hurt her leg and wasn't able to climb without oxygen. In 2013 she nearly made it to the top, but was forced to take oxygen at 8,504 meters while helping another climber.

    When Arnot finally stood atop Everest, she called her best friend, "I reached the top and I'm not using any oxygen." Then, tears began to stream down from her eyes. So much of Arnot's life has been about pushing the limits of her abilities, and in this case, she's also pushed up against the outer limits of the human spirit.

    It's 2035. You have a job, a family and you're about 40 years old. Welcome to our future life.

    Getting ready for work, you pause in front of the mirror. “Turn red,” you say. Your shirt changes from sky blue to deep red. Tiny preprogrammed electronics (智能电子元件) are rearranged in your shirt to change its color. Looking into the mirror, you find it hard to believe you're 40. You look much younger. With amazing advances in medicine, people in your generation may live to be 150 years old. You're not even middle aged!

    As you go into the kitchen and prepare to pour your breakfast cereal（谷物） into a bowl, you hear, “To lose weight, you shouldn't eat that,” from your shoes. They read the tiny electronic code on the cereal box to find out the nutrition details. You decide to listen to your shoes. “Kitchen, what can I have for breakfast?” A list of possible foods appears on the counter as the kitchen cheeks its food supplies.

“Ready for your trip to space,” you ask your son and daughter. In 2005 only specially-trained astronauts went into space—and very few of them. Today anyone can go to space for daytrips or longer vacations. Your best friend even works in space. Handing your children three strawberries each, you add, “The doctor said you need these for space travel.” Thanks to medical advances, vaccination shots (防疫针) are a thing of the past. Ordinary foods contain specific vaccines(疫苗). With the strawberries in their mouths, the kids head for the front door.

    It's time for you to go to work. Your car checks your fingerprints and unlocks the doors. “My office, autopilot,” you command. Your car drives itself down the road and move smoothly into traffic on the highway. You sit back and unroll your e-newspaper. The latest news downloads and fills the viewer. Looking through the pages, you watch the news as video film rather than read it.

    College graduation brings both the satisfaction of academic achievement and the expectation of a well-paid job. But for 6, 000 graduates at San Jose State this year, there's uncertainty as they enter one of the worst job markets in decades. Ryan Stewart has a freshly-minted (新兴的) degree in religious studies, but no job prospects.

    "You look at everybody's parents and neighbours, and they're getting laid off and don't have jobs," said Stewart. "Then you look at the young people just coming into the workforce... it's just scary."

    When the class of 2003 entered college, the future never looked brighter. But in the four years they've been here, the world outside has changed dramatically.

    "Those were the exciting times, lots of dot-com opportunities, exploding offers, students getting top dollar with lots of benefits," said Cheryl Allmen-Vinnidge of the San Jose State Career Center. "Times have changed. It's a new market."

    Cheryl Allmen-Vinnidge ought to know. She runs the San Jose State Career Center, sort of a crossroads between college and the real world. Allmen-Vinnidge says students who do find jobs after college have done their homework.

    "The typical graduate who does have a job offer started working on it two years ago. They've postured (定位) themselves well during the summer. They've had several internships (实习)," she said. And they've majored in one of the few fields that are still hot, like chemical engineering, accounting, or nursing, where average starting salaries have actually increased over last year. Other popular fields (like information systems management, computer science, and political science) have seen big declines in starting salaries.

    Ryan Stewart (he had hoped to become a teacher) may just end up going back to school. "I'd like to teach college some day and that requires more schooling, which would be great in a bad economy," he said.

    To some students, a degree may not be a ticket to instant wealth. For now, they can only hope its value will increase over time.