It was an autumn morning shortly after my husband and I moved into our first house. Our children were upstairs unpacking, and I was looking out of the window at my father moving around mysteriously on the front lawn. “What are you doing out there?” I called to him.

    He looked up, smiling. “I'm making you a surprise.'' I thought it could be just about anything. When we were kids, he always created something surprising for us. Today, however, Dad would say no more, and caught up in the business of our new life, I eventually forgot about his surprise.

    Until one gloomy day the next March when I glanced out of the window, I saw a dot of blue across the yard. I headed outside for a closer look. They were crocuses (番红花) throughout the front lawn—blue, yellow and my favorite pink, with little faces moving up and down in the cold wind. I remembered the things Dad secretly planted last autumn. He knew how the darkness and dullness of winter always got me down. What could have been more perfectly timely to my needs?

    My father's crocuses bloomed (开花) each spring for the next five seasons, always bringing the same assurance: Hard times are almost over. Hold on, keep going, and light is coming soon.

    Then a spring came with only half the usual blooms and the next spring there were none. I missed the crocuses, so I would ask Dad to come over and plant new bulbs (块茎植物). But I never did. He died suddenly one October day. My family were in deep sorrow, leaning on our faith.

    On a spring afternoon four years later, I was driving back when I felt depressed. It was Dad's birthday, and I found myself thinking about him. This was not unusual-my family often talked about him, remembering how he lived up to his faith. Suddenly I slowed as I turned into our driveway. I stopped and stared at the lawn. There on the muddy grass with small piles of melting snow, bravely waving in the wind, was one pink crocus.

    How could a flower bloom from a bulb more than 18 years ago, one that hadn't bloomed in over a decade? But there was the crocus. Tears filled my eyes as I realized its significance.

    Hold on, keep going, and light is coming soon. The pink crocus bloomed for only a day, but it built my faith for a lifetime.

    Staying positive through the cold season could be your best defense against getting ill,a new American study suggests.

    In an experiment that exposed healthy volunteers to a cold or flu virus,researchers found that people with a generally sunny character were less likely to fail ill.The findings,published in the journal Psychosomatic Medicine, build on evidence that a “positive emotional style” can help ward off the common cold and other illness.

    Researchers believe the reasons may be both objective―as in happiness improving immune function―and subjective―as in happy people being less troubled by a sore throat or runny nose.“People with a positive emotional style may have different immune responses to the virus,” explained lead study author Dr Sheldon Cohen of Carnegie Mellon University in Pittsburgh.“And when they do get a cold,they may interpret their illness as being less severe.”

    Cohen and his colleagues has found in a previous study that happier people seemed less likely to catch a cold, but some questions remained as to whether the emotional quality itself had the effect.

    For the new study,the researchers had 193 healthy adults complete standard measures of personality qualities, physicals health,and emotional “style”.Those who tended to be happy,energetic and easy –going were judged as having a positive emotional style,while those who were often unhappy,tense,and hostile had a negative style.

    Afterwards,the researchers gave them nose drops containing either a cold virus or a particular flu virus.Over the next six days,the volunteers reported on any aches,pains,sneezing they had,while the researchers collected objective data.Cohen and his colleagues found that happy people were less likely to develop a cold.

    What's more,when happy folks did develop a cold,their symptoms were less severe than expected based on objective measures.

    On the contrary,people with negative characters were not at increased risk of developing a cold based on objective measures,though they did tend to get down about their symptoms.

    “We find that it's really positive emotions that have the big effect,” Cohen said,“not the negative ones.”

    So can a bad-tempered person fight a cold by deciding to be happy?

    Would you buy a car that released calming smells into the air when you are stuck in heavy traffic? Would you buy a robot that smells like a human being?

    Many people have seen the 3-D computer-made environments of virtual reality (VR). Now these virtual worlds will not just look and sound real. Researchers have created VR environments that even smell like the real things. With the new technology, users open a virtual door and step into a new environment, like a rainforest. After they enter this virtual world, special equipment releases forest-like smells into the air to make the experience seem more real.

    Suzanne Fisher-Murray said, “it is a really wonderful experience that you have because you're exploring this environment and you have smells with it.”

    In the United States, Smell-O-Vision was designed to provide smells during the showing of a movie. The Smell-0-Vision system was once popular in the 1960s. Now, Emanuela Maggioni says it is close to becoming popular again. “The connection with emotions, memories, and…the sense of smell,” Maggioni said. “It is unbelievable what we can do with technology.”

    The uses for smell technology are not just limited to films and the performing arts. Researchers showed a computer program where users could imagine themselves driving a car. The system included a special smell-spraying machine. Dmitrijs Dmitrenko said, “We want to deliver the smell of lavender（薰衣草）every time the person drives over the speed limit. We choose lavender because it's a very calming smell.”

    Scientists are experimenting with smell instead of sounds or image-based alerts on telecommunications equipment. And businesses are already using smell to influence people's behavior. “Not only.…in stores…But on the other side, you can create and stimulate immediate buying,” Maggioni said. “So you're in a library and you smell coffee and actually you are unconsciously having the need to drink a coffee.”

    The hemlock(铁杉) trees along the Wappinger Creek, New York, look healthy. However, scientist Gary Lovett says the white balls which provide protection for the bugs are created by a tiny insect. It's hard to believe the tiny bug could kill a tree. However, trees can end up with millions and millions of the pests. When there are that many, it ends up killing the tree.

    The bug from East Asia is slowly killing trees across the USA. The trouble－making bug is just one of many invasive(入侵的) pests that have slipped into the United States. They can hurt other living things in their new home.

    Many invasive pests arrive on wooden pallets piled inside shipping containers. They support and separate goods, and keep them from sliding around. Invasive pests often tunnel into the pallets.  How can we stop pests from riding on pallets? Lovett says new rules are needed. The companies that make pallets don't want more rules. Congress has added an amendment(修正案) in the 2018 Farm Bill to try and prevent this problem. However, Lovett is not hopeful it will make much of a difference. Pallets are checked by inspectors. Many are sprayed with bug－killing pesticide. "I believe in the system，" said Brent McClendon, president of The National Wooden Pallet and Container Association. He also said shipping containers are checked very carefully.

    Still, each year 13 million containers are shipped to the U.S. Each is full of wooden pallets. Lovett says: "Inspectors can't possibly check everything. All it takes are a few bad pallets; we should get rid of wooden pallets." He believes pallets should be made of plastic or eco－composite wood. Eco－composite wood is a mix of wood fiber and plastic. Insects cannot hide into it. One problem is that these choices cost more. They may be worth the extra money, though. Invasive pests cost the U.S. $5 billion a year. Trees don't just die in forests. They also die in cities and our yards. Then, they need to be replaced. That costs money, too.

    Do you often feel that you aren't taking in as much of the joy around you as you could? I recently caught myself feeling this way, and based on a suggestion by John Horton, coauthor (合著者) of The Inner Game of Stress, I put myself on a 30-day life-appreciation course.

    The only assignment each day was to go outside and appreciate life.

    So I started by taking in the beauty around me. During the first few days, I was able to appreciate my surroundings, although it was an intellectual appreciation, not an emotional one.

    After the first week, it was more uncomfortable to lie in bed and think about things than it was to get up and see them for myself.

    If you often wake up feeling anxious or depressed, or if you don't look forward to each day, then you need to try this course for yourself.

    It's an inner workout that you can do anywhere. It may not change your life, but it will adjust your attitude, and that's pretty helpful in this crazy world.

    I have always believed in ending the day on a positive note by writing a word or two in a gratitude journal and saying something sweet to my wife about the day we shared.

    Now, I have a new morning habit. It hasn't changed my routine one bit, but it has changed the way I look at the world.

    Creating a new habit isn't about perfection – it's about getting what you want by creating a change in your behavior and thinking.

    So now, while I'm making my coffee in the morning, I'm also appreciating what I have.

    It's quick, fulfilling, and a much better way to start my day than looking at my phone or computer.

    And because of this, my attitude is better, as I've already begun my morning on a positive note rather than a problematic one.

    The idea here is that if you can appreciate your life, it actually changes the way you feel about it.

    Appreciation will give you more energy to live the way you would like to live.

    As a means of improving our mood, it's highly underrated (被低估的). The easy task of appreciating what we have simply makes life better.

A living robot has been created out of frog skin cells. Xenobots, named after the frog species Xenopus laevis that the cells come from, were first described last year. Now the team behind the robots has improved their design and demonstrated new capabilities.

To create the xenobots, Michael Levin at Tufts University in Massachusetts and his colleagues obtained tissue from 24-hour-old frog embryos after very small physical operation. Where the previous version relied on the contraction of heart muscle cells to move them forward by pushing off surfaces, these new xenobots swim around faster. They also live between three and seven days longer than their previous generation, which only lasted about seven days, and have the ability to sense their surroundings to some extent, turning red when exposed to blue light.

"The fundamental finding here is that when you free skin cells from their normal context, and you give them a chance to build other things than what they normally build," says Levin. "To me, one of the most exciting things here is that they are plastic. This idea that even normal cells, not genetically modified, are in fact capable of building something completely different."

Because they are created from cells, the xenobots eventually break apart and are totally biodegradable, says team member Douglas Blackiston, also at Tufts University. He therefore hopes that they can be used for biomedical and environmental applications.

Previous attempts at creating living robots, such as a wirelessly controlled cockroach, have involved dealing with live animals, raising ethical concerns. Xenobots differ from these because they are made entirely of living cells. "The approach here is maybe ethically the least problematic because everything starts with cells. They have no neurons, so it's not an animal," says Auke ljspeert at the Swiss Federal Institute of Technology at Lausanne, who wasn't involved in the research. "It's really cells, so I find it maybe the cleanest way."