After a few moments, my passenger started a conversation. It began ordinarily enough: "How do you like driving a cab?"

    "It's OK," I said. "I make a living and meet interesting people sometimes. How about you? His reply intrigued me.

    "I would not change jobs even if I could make twice as much money doing something else."

    I'd never heard that before. "What do you do?''

    "I'm in the neurology department at New York Hospital."

    Then I decided to ask for this man's help. We were not far from the airport.

    "Could I ask a big favor of you? I have a son, 15, a good kid. He wants a job, but a 15-year-old can't get hired unless his old man knows someone who owns a business, and I don't." I paused. "Is there any possibility that you could get him some kind of summer job?"

    He didn't respond for a while. Finally, he said: "Well, the medical students have a summer research project. Maybe he could fit in. Have him send me his school record." I tore off a piece of my brown lunch bag, and he scribbled his name on it and paid me. It was the last time I ever saw him.

    After I nagged, yelled, and finally threatened to cut off his pocket money, my son Robbie sent off his grades to the guy the next morning.

    Two weeks later, when I arrived home from work, my son was beaming. He handed me a letter from my passenger, saying he was to call my passenger's secretary for an interview.

    Robbie got the job. He did minor tasks, unpaid, but he fit in well. The following summer, he worked at the hospital again with more responsibility. As high school graduation neared, Dr Plum was kind enough to write letters of recommendation for Robbie and he was accepted by Brown University. Finally, Dr Robert Stern, the son of a taxicab driver, became OB-GYN chief president at Columbia-Presbyterian Medical Center.

    Some might call it fate, and I guess it was. But it shows that something as ordinary as a taxi ride can change your life.

    Plastics remain one of the most - used materials for making many things. Things made of plastics can be very strong and last a long time. Plastics are also much lighter than metal and can easily be formed into different shapes. Plastics can take hundreds of years to break down on their own. And very few kinds are highly recyclable.

    A team of researchers working at the US Department of Energy says it has created a kind of plastic that could lead to products that are 100 percent recyclable. It recently reported the discovery in a study in the journal Nature Chemistry.

    The researchers say the new material is a plastic polymer (聚合体)called polydiketoenamine, or PDK. The team reports the material can be broken down in parts at the molecular (分子的)level. It can then be built up again to form plastics of different shapes, textures and colors. The researchers say this process can be repeated over and over again—without the plastic material losing any performance or quality.

    "Most plastics were never made to be recycled," lead researcher Peter Christensen said in a statement. " But we have discovered a new way to assemble plastics that takes recycling into consideration from a molecular perspective. "

    Many plastics have different chemicals added to them to make them more useful and powerful. The problem is that these chemicals attach to the monomers (单体), which remain in plastics even after the material gets processed at a recycling plant. The research team reported that, with the newly discovered PDK material, the monomers could be recovered and separated from any chemical additives.

    Next, the researchers plan to develop PDK plastics "with a wide range of thermal and mechanical properties. These plastics could be used for many kinds of cloth, as well as things such as 3D printed materials and foams. In addition, the team is trying to include plant - based materials in the process.

Humans' overconsumption of resources is a leading contributor to global climate change, says University of Arizona researcher Sabrina Helm. Therefore, it's increasingly important to understand the choices consumers make and how those decisions affect the health of a planet with limited resources. In a new study, published in the journal Young Consumers, Helm and her colleagues explore how materialistic values influence pro-environmental behaviors in millennials, who are now the nation's most influential group of consumers.

The researchers focused on two main categories of pro-environmental behaviors: reduced consumption, which includes actions like repairing instead of replacing older items; and "green buying," or purchasing products designed to limit environmental impacts. The researchers also looked at how engaging in pro-environmental behaviors affects consumer well-being.

More materialistic participants, the researchers found, were unlikely to engage in reduced consumption. However, materialism did not seem to have an effect on their likelihood of practicing "green buying." That's probably because "green buying," unlike reduced consumption, still offers a way for materialists to fulfill their desire to get new items, Helm said.

Study participants who reported having fewer materialistic values were much more likely to engage in reduced consumption. Consuming less was, in turn, linked to higher personal well-being and lower psychological suffering. Green buying—which may have some positive environmental effects, although to a smaller degree than reduced consumption—was not found to improve consumer well-being, Helm said.

The take-home message for consumers: "The key is to reduce consumption and not just buy green stuff. Having less and buying less can actually make us more satisfied and happier," Helm said. "If you have a lot of stuff, you have a lot on your mind," she said. "For example, it requires maintenance and there's a lot of burdens of ownership, and if you relieve yourself of that burden of ownership, most people report feeling a lot better and freer."

Helm and her colleagues additionally looked at how materialism affects millennial consumers' proactive financial behaviors, such as budgeting and saving. Examining financial behaviors alongside pro-environmental behaviors provides a picture of how young adults proactively deal with resource limitations in two contexts: environmental and financial, Helm said.

As expected, Helm and her colleagues found that those who reported having more materialistic values engaged in fewer proactive financial behaviors than their less materialistic counterparts (对应的人). The researchers also found that, consistent with previous studies, proactive financial behaviors were associated with better personal well-being, life satisfaction and financial satisfaction, as well as lower psychological suffering.

Understanding how materialistic values impact consumer behaviors, and how those behaviors in turn affect personal and environmental well-being, is important, Helm said. However, she acknowledges that for many consumers, shifting behaviors to be more financially proactive and consume less will be challenging.

In recent years American society has become increasingly dependent on its universities to find solutions to its major problems. It is the universities that have been to blame for developing the expertise to place men on the moon; for dealing with our urban problems and with our worsening environment; for developing the means to feed the world's rapidly increasing population. The effort involved in meeting these demands presents its own problems. In addition, however, this concentration on the creation of new knowledge significantly impinges on the universities' efforts to perform their other principal functions, the transmission and interpretation of knowledge-the imparting of the heritage of the past and the preparing of the next generation to carry it forward.

With regard to this, perhaps their most traditionally acknowledged task, college and universities today find themselves in a serious situation. On one hand, there is the American commitment, especially since World War Ⅱ, to provide higher education for all young people who can profit from it. The result of the commitment has been a dramatic rise in enrollments(登记入学) in our universities, coupled with a striking shift from the private to the public sector of higher education. 

On the other hand, there are serious and continuing limitations on the resources available for higher education. While higher education has become a great "growth industry", it is also at the same time a tremendous drain(耗竭) on the resources of the nation. With the vast increase in enrollment and the shift in priorities away from education in state and federal(联邦的) budgets, there is in most of our public institutions a significant decrease in expenses for their students. One crucial aspect of this drain on resources lies in the persistent shortage of trained faculty(全体教师), which has led, in turn, to a declining standard of competence in instruction.

Intensifying these difficulties is, as indicated above, the concern with research, with its increasing claims on resources and the attention of the faculty. In addition, there is a strong tendency for the institutions' organization and functioning to fulfill the demands of research rather than those of teaching.

Quantum mechanics (量子力学) is a branch of science that studies the smallest particles (粒子) in the universe, like atoms (原子) and even smaller things. It might sound super complex, but let's break it down in simple language.

Imagine you have a small particle, like an atom. In the world of quantum mechanics, these particles don't behave like the things we see in our everyday lives, like balls or cars. Instead, they act kind of like waves and particles at the same time, which is really strange!

One of the most famous ideas in quantum mechanics is the "Uncertainty Principle", raised by physicist Wemer Heisenberg. This principle says that we can't precisely know both the position and the speed of particle at the same time. It's not because our measuring tools are bad; it's because the particles themselves are naturally uncertain.

Another weird thing about quantum mechanics is something called "Entanglement". Imagine you have two particles that are connected in a special way. If you change one of them, the other instantly changes, no matter how far apart they are. It's like they're talking to each other faster than the speed of light, which goes against what we know from everyday experiences.

Quantum mechanics also deals with probabilities. Instead of saying, "This particle will be here at this exact time," scientists say, "There's a certain chance it'll be here, and a certain chance it won't." It's like predicting the weather, but on a super small scale.

In a nutshell, quantum mechanics is a strange and fascinating world where particles act both like waves and particles, where you can't know everything about a particle at once, and where particles can be mysteriously connected no matter how far apart they are. It's a mind-boggling field that challenges our understanding of how the universe works, and even though it's tough to grasp, it's an essential part of modern physics.

A teenager needs to have a sense of independence in their life to feel secure(安全的). To some teenagers independence means a lot to them, and I think that some parents don't allow their teenagers enough independence.

Independence has something to do with freedom. Some kids are not allowed to go anywhere alone, and the only thing their schedule includes is going to school, coming home, going to sleep, and repeating the process the next day. Parents tend to be afraid that their kids can get hunt if they go outside into the world. But if parents control their kids too much, they may never learn to live on their own. The best way for a teenager to learn lesson is through experience. I think it is beneficial for teenagers to have freedom.

Teenagers' lack of freedom can also stop them from having good friendship at school. Some might say this is a good thing, because it helps them focus more on their school work. I argue that this can only discourage them not to do their school work. Some parents do not allow their children to be around their friends outside the school, thinking that this will get them into trouble. But I don't think so. Instead, isn't this a good reason for parents to get their children a cellphone? Cellphones allow teenagers to stay in touch with their parents, and communicate with friends.

Privacy is another issue between parents and their teenagers.Teenagers tend to enjoy relaxation by themselves in their own room. This also gives them a sense of independence. It often annoys teenagers when their parents enter their room when they are not home. I know that my mom always goes in my room when I'm not home, and this has brought me to the point where I have asked many times to get a lock on my door.