Each time I see a balloon, my mind flies back to a memory of when I was a six-year-old girl. It was a rainy Sunday and my father had recently died. I asked my mom if Dad had gone to heaven. "Yes, honey. Of course." she said.

    "Can we write him a letter?"

    She paused, the longest pause of my short life, and answered, "Yes."

    My heart jumped. "How? Does the mailman go there?" I asked.

    "No, but I have an idea." Mom drove to a party store and returned with a red balloon. I asked her what it was for.

    "Just wait, honey. You'll see." Mom told me to write my letter. Eagerly, I got my favorite pen, and poured out my six-year-old heart in the form of blue ink. I wrote about my day, what I learned at school, how Mom was doing, and even about what happened in a story I had read. For a few minutes it was as if Dad were still alive. I gave the letter to Mom. She read it over, and a smile crossed her face.

    She made a hole in the corner of the letter where she looped the balloon string. We went outside and she gave me the balloon. It was still raining.

    "Okay, on the count of three, let go. One, two, three."

    The balloon, carrying my letter, darted upward against the rain. We watched until it was swallowed by the mass of clouds.

    Later I realized, like the balloon, that Dad had never let his sickness get him down. He was strong. No matter what he suffered, he'd persevere, hang on, and finally transcend this cold world and his sick body. He rose into sky and became something beautiful. I watched until the balloon disappeared into the gray and white and I prayed that his strength was hereditary. I prayed to be a balloon.

    When many people are worried that there are no more heroes in modern times, two university students who lost their lives to rescue drowning children have shown that heroes still exist (存在).

    According to the Inner Mongolia Morning Post, the accident occurred on the afternoon of December 14, 2002 when three school students skating on a frozen lake in Qingcheng Park in Hohhot fell through the ice into the freezing water.

    More than 20 university students who happened to be near the spot immediately went to the rescue of the children.

    Two children were quickly rescued, but the third died. The child's body was not found for three hours. Two of the rescuers, Liu Ye and Hao Longbiao, also died of cold and exhaustion (筋疲力尽).

    The body of Hao who took the lead in jumping into the lake was not found until the next day.

    A student who was unwilling to tell his name said he and his classmates from the local college were taking photos at the lake. When they heard the children's cries for help, they went to the ice hole hand in hand to rescue the children. But the ice kept breaking, causing most of them to fall into the icy water.

    Local residents held mourning ceremonies (祭奠仪式) at the lake.

    Eight of the students were seriously affected by the freezing water and were being kept in hospital for further observation, but their lives were no longer in danger.

    Dujiangyan is the oldest man­made water system in the world, and a wonder in the development of Chinese science. Built over 2, 200 years ago in what is now Sichuan Province in Southwest China, this amazing engineering achievement is still used today to irrigate over 6, 000 square kilometers of farmland, take away floodwater and provide water for 50 cities in the province.

    In ancient times, the region in which Dujiangyan now stands suffered from regular floods caused by overflow from the Minjiang River. To help the victims of the flooding, Li Bing, the region's governor, together with his son, decided to find a solution. They studied the problem and discovered that the river most often overflowed when winter snow at the top of the nearby Mount Yulei began to melt as the weather warmed.

    The simplest fix was to build a dam, but this would have ruined the Minjiang River. So instead Li designed a series of channels built at different levels along Mount Yulei that would take away the floodwater while leaving the river flowing naturally. Better still, the extra water could be directed to the dry Chengdu Plain, making it suitable for farming.

    Cutting the channels through the hard rock of Mount Yulei was a remarkable accomplishment as it was done long before the invention of gunpowder and explosives. Li Bing found another solution. He used a combination of fire and water to heat and cool the rocks until they cracked and could be removed. After eight years of work, the 20­metre­wide canals had been carved through the mountain.

    Once the system was finished, no more floods occurred and the people were able to live peacefully and affluently. Today, Dujiangyan is admired by scientists from around the world because of one feature. Unlike modern dams where the water is blocked with a huge wall, Dujiangyan still lets water flow through the Minjiang River naturally, enabling ecosystems and fish populations to exist in harmony.

    Some kinds of mental skills naturally decrease as people get older. Yet research seems to show that some training can improve such skills. A recently published study also appears to attest that the good effects of training can last for many years after that training has ended.

    Researchers at Johns Hopkins University in Maryland wanted to learn how long memory and thinking skills would last in older people who were trained to keep them. The people were part of the ten-year research project. They were taught methods meant to improve their memory, thinking and ability to perform everyday tasks.

    More than 2,800 volunteered for the study called ACTIVE ­ short for Advanced Cognitive Training for Independent and Vital Elderly. Most were studied when they were more than 70 years old.

    The volunteers took one of several short training classes meant to help them keep their mental abilities. One class trained participants in skills including how to remember word lists. Another group trained in reasoning. A third group received help with speed-of-processing ­ speed of receiving and understanding information. A fourth group ­ the control group did not get any training.

    Earlier results had established that the training helped the participants for up to five years. Now, leading study writer George Rebok says, the research showed most of the training remained effective a full ten years later.

    Professor Rebok and his team found that the people trained in reasoning and speed-of- processing did better on tests than the control group.

    "We are wondering whether those effects which endured over time would still be there ten years following the training, and in fact, that's exactly what we found.

    The effect on memory, however, seemed not to last as long. Still, the old people in any of the three classes generally reported less difficulty in performing daily activities than the control group. The total training time for the older people was between 10 and 15 hours.

Owls and Larks

    Larks are most likely to be healthy, wealthy and wise, according to the old saying.

    But those who are early to bed and early to rise do not always have the upper hand, researchers say. They have found that night owls are generally brighter and wealthier than those able to get up early in the morning.

    Experts from the University of Madrid carried out tests on around 1,000 teenagers and found that those who preferred to stay up late proved the kind of intelligence associated with honored jobs and higher incomes. "Larks" or "morning people", however, often acquired better exam results, possibly because lessons are held at the wrong time of day for night owls. The researchers examined the habits and body clocks of the youngsters to determine whether they liked to stay up late and sleep later in the morning, or preferred to go to bed early and were at their peak in the morning. School performance and inductive(归纳的)intelligence, or problem solving, were measured and academic grades in the major subjects were also taken into account. The results showed that evening types scored higher than morning types on inductive reasoning, which has been shown to be a good estimate of general intelligence and a strong indicator of academic(学术的) performance. They also had a greater capacity(能力) to think conceptually(概念地) as well as analytically. Such abilities have been linked to innovative(创新的) thinking, more admired occupations and better incomes.

    Famous night owls include President Trump, Obama, Charles Darwin, Winston Churchill, Keith Richards and Elvis Presley. George W. Bush, who is regularly in bed by 10 p.m., Thomas Edison, Napoleon, Condoleezza Rice, who wakes at 4:30 a.m., and Ernest Hemingway are among those known as larks. Jim Horne, professor of psychophysiology at Loughborough University, said, "Evening types tend to be the more active and creative types, the poets, artists and inventors, while the morning types are the deducers(推导者), as are often seen with civil servants and accountants." A previous study of US Air Force recruits found that evening types were much better at thinking to solve problems than larks.

This was no ordinary class. The students who came together were all science or engineering professors at Cornell University. They had interrupted their research to accept an invitation to take part in an unusual experiment: "an interesting week of poetry". This class was part of a study to answer the questions: Why is science difficult for many non-science students? What can teachers learn about teaching if they take a class that is not in their field? 

The students in the poetry class listened to lectures and took notes. They had reading tasks and had to write three short papers. All students noticed one thing—the importance of spoken words. In science and engineering classes, the instructors put tables and drawings on the blackboard. But in this poetry class, the instructors just talked. They didn't write anything on the board.

The scientists and engineers noticed one similarity between science and poetry. In both subjects, students need to find layers of meaning. Some layers are simple, clean, and on the surface;   other layers are deeper and more difficult. This search for different levels of meaning doesn't happen much in undergraduate science classes, but it is important later, in a graduate school. And it is always important in humanities (人文学科).

Both the poetry instructors and their students learned something about teaching from this experience. One poetry instructor, for example, now sees the importance of using careful, clear definitions when he explains a poem. He also plans to be more informative as he teaches. Most of the scientists agreed on several points. Firstly, humanities classes might help science students to see patterns and decide which information is important. Secondly, the poetry class was fun. One engineer decided, "We need to change the way we teach engineering to make it an enjoyable experience for students."

But perhaps the most important result of the experience was this: all of the professors began to think about how they teach and how they can teach better.