Invented in the Tang Dynasty and widely adopted after the Song Dynasty in Fujian, the watertight-bulkhead(水密舱壁) technology permits the construction of ocean-going ships with watertight compartments(隔层). If one or two cabins are accidentally damaged at sea, water will not flood the other cabins and the ships will remain afloat.

The experience and working methods of watertight-bulkhead technology are transmitted orally from master to apprentices. However, the need for Chinese junks(中国式帆船) has decreased sharply as wooden ships have been replaced by steel-hulled ships, and today only three masters can claim full command of this technology. Associated building costs have also increased owing to a shortage in raw materials. Therefore, the inheritance(继承) of this heritage is decreasing, and inheritors are forced to seek alternative employment.

Zhang Guohui, a 77-year-old inheritor of the watertight-bulkhead techniques used to make Chinese junks, has been making ships for more than six decades. Coming from a poor family in a fishing town in East China's Fujian Province, Zhang started to make a living at the age of 16fishing on the open seas, which is where he developed a keen interest in constructing boats. As a fast learner, Zhang was later sent to shipyards in the cities of Quanzhou and Xiamen in Fujian Province, where he received training and became a master of traditional Chinese junks and gained fame because of his extremely skilled craftsmanship in the construction of these junks.

In fear that the traditional skills would die someday, Zhang started to restore old ships and make model junks for the museum with his 20 years of shipbuilding skills. "The restored ancient ships are the historical witnesses of Quanzhou as a maritime center of the East and Southeast Asiatrade network," said Zhang, adding that he finds the work meaningful since younger generations can learn from exhibitions of ancient ships that their ancestors had advanced shipbuilding technology at an early stage of development. "As long as I'm alive, I'll keep passing on the heritage," he said.

"What beautiful music!" I shout loudly as my 9-year-old son practices playing the violin. He's used to this praise; I give rewards like that most days. But every once in a while, I skip it, and when I do, I can see the disappointment on his face when he's finished.

Am I a bad mom? Conventional wisdom says that consistency is key to parenting since it enables your child to predict how you'll react, leading to good behavior. And it's true that children need some level of predictability in their lives, particularly when it comes to discipline.

But research suggests that inconsistent gifts and praise can have a greater effect on motivation. While we all like to live in a predictable world, we often respond more strongly to unpredictable rewards.

In one experiment, my colleagues and I told participants they'd be paid if they could drink about one-and-a-half quarts of water in two minutes or less. In one condition, we offered people a $2 fixed reward. In another, there was an uncertain reward of either $2 or $1. The certain reward was a better deal, yet many more people successfully met the challenge when assigned an uncertain reward. Resolving the uncertainty—whether they would win $1 or $2—was significantly more motivating than winning $2 for sure.

Here is one of the reasons why uncertainty is motivating. What scientists call "intermittent (间歇性) reinforcement" —rewarding behavior on some but not all occasions—makes it morearduous to know when rewards will show up. If you very often, but don't always, praise your child for completing their chores, they'll keep up the good behavior in the hope of receiving praise the next time.

So don't assume that if kids are always praised for finishing their homework, they'll be more likely to do it. Do praise young people for a job well done, just not every time. And pick rewards out of a hat when they complete chores—the surprise prize might keep everyone motivated to get things done.

At first, Dorothy Sorlie thought she was just getting old, though not as gracefully as she'd hoped. Retired from teaching English at a local college, Sorlie, then 74, began losing interest in things she'd enjoyed, including reading and cooking. She couldn't concentrate. Her handwriting changed. The symptoms occurred so gradually that initially she wasn't aware anything was happening.

Things kept getting worse. She started worrying that she might be developing early dementia (痴呆). The physical symptoms progressed too. Most worrisome, she began having trouble walking and started falling. Through it all, her doctors struggled to explain what was happening.

She and her husband, Jim Urness, were desperate for answers; It would take years before they got them. The doctors' diagnoses (诊断), all incorrect, could account for one or two of Sorlie's symptoms but not all of them, and none of the treatments seemed to help.

The couple traveled across the country looking for someone who could tell them what was wrong. However, one possible explanation for her symptoms after another proved incorrect. At last, Sorlie's primary care doctor, Kevin Wergeland found the disease responsible for all her symptoms was a little-known condition called normal pressure hydrocephalus (NPH). Although her condition was detected at an advanced state, it was treatable.

In fact, NPH is sometimes referred to as "treatable dementia". It is an insidious (潜伏的) and mysterious disorder that can copy many more common problems including Alzheimer's and Parkinson's. An estimated 700000 people in the United States have NPH, although ifs believed that fewer than 20 percent of them are correctly diagnosed.

Sorlie is now free of NPH symptoms, and taking advantage of her good health and using her dramatic recovery to inform others about NPH. She gives presentations to local senior centers as a volunteer. "If this awareness can help one person avoid what my husband and I endured, " Sorlie says, "then my efforts are worth it. "