In London's art gallery six or seven men, mostly in their 30s, are busy painting the walls with new designs in colorful lettering and clever tricks. Tins of spray paint and beer stand on the ground. The atmosphere is not unlike that of a golf course: a mix of concentration and relaxation.

    Graffiti(涂鸦) painting is traditionally a daring hobby. Teenagers avoid security guards to put their names on trains and buses. But over the past decade that has almost disappeared from Britain's cities. Between 2007 and 2017 the number of incidents of graffiti recorded by the British Transport Police fell by 63%. A survey by the environment ministry shows that fewer places are damaged by tags(绘名) than ever. Graffiti are increasingly limited to only a few walls. In time the practice may die out entirely.

    The most obvious reason for the decline in tagging and train-painting is better policing, says Keegan Webb, who runs The London Vandal, a graffiti blog (博客). Numerous cameras mean it is harder to get away with painting illegally. And punishments are more severe. A generational change is apparent, too. Now teenagers prefer to play with iPads and video games. Those who do get involved tend to prefer street art to graffiti. And the internet helps painters win far more attention by posting pictures online than they can by breaking into a railway yard.

    Taggers and graffiti artists mostly grew up in the 1980s and 1990s. Those men are now older and less willing to take risks. "We can't run away from the police any more," says Ben Eine, who turned from tagging to street art. The hip-hop culture that inspired graffiti in the first place has faded. Video games and comic books provide more inspiration than music.

    Graffiti may eventually disappear. But for now the hobby is almost respectable. Mr Eine says he has lots of friends who used to paint trains. Now with wives and children, they paint abandoned houses at the weekend. It has become something to do on a Sunday afternoon—a slightly healthier alternative to sitting watching the football.

    Durian(榴莲) is probably the smelliest fruit in the world, letting out an unusual unpleasant smell which would make anyone bring up. However, nobody was aware of what gave this fruit its unique smell, so a team of researchers from Singapore decided to take a look at its genome (基因组) and find out,

    Durian is well-known throughout Southeast Asia as the king of fruits, mostly because of its awful appearance and smell. However, the origin of this unpleasant smell was unknown, so researchers decided to map the genome of the fruit, and find the gene that controlled it. A group of genes, volatile sulfur compounds (含硫化合物), became very active in the fruit, and they were found responsible for resulting in the unpleasant smell.

    The fruit confuses everyone with a sulfuric smell, like rotten onions and ingredients. The smell lasts long, mostly because the fruit contains more volatile sulfur compounds. Other species usually benefit from two gene copies at most, but durian has four, leading to the striking smell.

    However, this smell might be an advantage for durian in the wild. Although we find it unpleasant, many animals might be attracted by it. If they eat the fruit, then they can easily spread its seeds everywhere, thus contributing to the distribution of the species.

    The mapping of the durian genome also showed some other information on the species. First of all, the fruit has an impressive number of genes, namely 46,000. Also, with the help of these genes, they saw how it evolved, and discovered it was related to the cacao tree. All the other discoveries have been published in the journal Nature Genetics.

    Despite the striking smell, many people actually enjoy eating the fruit. However, not all durian species are edible, and some of them may even cause damage to our health, Even so, the fruit is often imported, significantly contributing to the economy.

    I'll never forget the day when Mary came into my office and said, I am too old to learn how to use a computer. I shook my head. Here was a woman who had raised 6 children and who had made great progress in her career telling me that she was too old to learn something new. I told her that I always believed people were never too old to learn.

    Mary followed my advice and did learn how to use the computer. Now, she is retired and leading a very active life volunteering in her community( 社区 ),using her computer skills and helping anyone that needs help.

    When she was in her sixties, one day she called me and said she had played the piano for others all her life, and now she was going to make a CD of her own. My mind flashed back to the day when she told me she was too old to learn. You can imagine my surprise and delight.

    To produce the CD, she had a lot of things to learn. It was not just sitting at the piano and playing. She had to research the songs, learn about copyright(版权),and learn about marketing. It was pretty amazing for someone who once said she was too old to learn. And finally she made it. Now she has her own CD-Mixed Blessings.

    Most of you probably have heard about some people who have gone back to university in their seventies and have also graduated. They are on their way again to charging themselves with a new skill and a new attitude towards life. The point is you are unable to learn anything at any age if you believe you are too old. On the contrary, you can achieve anything at any age if you believe you can.

    Angel Garcia Crespo is a computer engineer at Carlos III University of Madrid in Spain. His group has invented a new way for deaf-blind people to “watch” TV. The idea for the technology grew out of previous work by his group. The team had already worked on making audiovisual(视听的) materials accessible to people with either vision or hearing disabilities. But the group wanted to help people with both challenges. So they asked some deaf-blind people what would help.

    In addition to relying on their sense of touch to communicate, deaf-blind people can also get and send information with a Braille line. The Braille system uses patterns of raised dots to stand for letters and numbers. A Braille line is an electronic machine with a changeable Braille display. Dots rise up or drop down based on the information sent to the machine.

    Now the new system changes TV signals to data a Braille line can use. “The key to the system is the possibility of using subtitles(字幕) to collect TV information, " Garcia Crespo explains. "Subtitles travel with the image(影像) and the audio in electromagnetic waves we don't see. But an electronic system can keep those waves."

    First, a computer program, or app, pulls out the subtitles and visual descriptions from the broadcast signal. The system then combines the information and changes both into data for Braille.

    Now another app gets to work, which sends the data out to people's Braille lines on demand. “This is done in real time, in less than a second, " Garcia Crespo says. This lets a deaf-blind person "watch" TV as it's broadcast. The system will work with various Braille lines, as long as there's a bluetooth connection available. Now, the system is only used in Europe, and it should soon be available in the US.

Volunteer Day

    What better way is there to enjoy your own hobbies while helping others at the same time? Come to Volunteer Day and choose which activity you'd like to join for the day. See below for a schedule of events on Volunteer Day.

    Volunteer Day schedule:

    7:30a.m.: Meet at the Community (社区) Center for juice and bagels.

    8:00—8:30 a.m.: Choose which activity you'd like to help with for the day.

    8:30 a.m.: Board the bus to your activity site.

    9:00 a.m.—3:30 p.m.: Work as a volunteer.

    3:30 p.m.: Board the bus that will take you back to the Community Center.

    See below for a list of volunteer opportunities for Volunteer Day so you can begin thinking about which activity you might want to join.

    A list of volunteer activities:

    Paint houses: Do you enjoy making art? If so, this volunteer opportunity might be just right for you! Happy Homes is a local organization that provides home repairs for needy people in the form of painting. For elderly or physically disabled people who cannot do repairs to their homes, Happy Homes provides volunteer painters to repaint old homes; outside or in. Happy Homes also provides painters to create beautiful wall paintings inside schools or community centers.

    Plant flowers: Do you enjoy being outside in nature? City Parks Association has many great opportunities for people who love to be outdoors. Help plant flowers and bushes in city parks; help lay paths at Cave Springs Park, or help pick up rubbish around the river banks. These activities are very active, so remember to be prepared with plenty of drinking water!

    Read to children: Do you enjoy working with young children? Do you like books? Love and Learning is an organization that provides volunteers to help children with learning disabilities. Read books out loud to groups of children four to six years old, or read one-on-one with struggling readers seven to eight years old.

    Play with animals: Do you love animals? Lovely Friends is an organization that visits local animal shelters and provides volunteers to spend time with the animals while their cages are being cleaned. Play with puppies, snuggle with cats, or hand-feed rabbits.

    Which country can you travel to in 2020 that will allow you to go for longer, enjoy a higher standard, and save more money? The following destinations offer accommodation, transportation, and food for less.

Kyrgyzstan, $25/day

    Kyrgyzstan is the choice for most travelers interested in trying out Central Asia, and most well-suited to travelers of all budgets. Food is cheap, so is getting around using the minibuses. You can find hostels and local home stays for less than $10. Meals cost $4 – $8 per day.

    Romania, $33/day

    If you are planning a European trip that's affordable and a little bit off the beaten path, Romania is perfect for you. Unlike other popular places, many charming towns here remain unknown to most foreigners. You can also take free walking tours in the numerous historical sites. Hostels run $10 – $15 per night, food is hearty and delicious, and the public transportation is reliable and affordable. Meals cost $10 – $15 per day.

    Arizona & Utah, $55/day

    For an American Southwest road trip, you'll spend an average of $110/day when you are solo. If you have just one other person, you'd be able to split the costs almost perfectly in half. If you have two other people along, take it down to one third and so on. The more the merrier.

    South Africa, $40/day

    Any hostels in South Africa are in beautiful settings and each has a unique personality, and affordable too. Food can get expensive. To save money, cook your own food. Grocery stores are plentiful and have reasonable prices. By at least cooking your own breakfast, you can save a lot of money. The best (and possibly cheapest) way to get around the country is to rent a car and share with 3 other people. Meals cost $12 – $15 per day.