On Monday, the Centers for Disease Control and Prevention predicted that 42% of Americans could be overweight by 2030. Our expanding bodies not only lead to a medical problem, but also endanger personal safety in some situations—in an airplane crash, for example, according to a recent article in The New York Times.

The New York Times' Christine Negroni reports that engineers and scientists are questioning whether airplane seats are designed to protect overweight travelers. Government standards(标准) for airplane seat strength—first set more than 60 years ago—require that the seats be made for a passenger weighing 170 pounds. Today, the average American man weighs nearly 194 pounds and the average woman 165 pounds. Negroni reports:

     “If a heavier person completely fills a seat, the seat is not likely to behave as designed during a crash,” Robert Salzar, the leading scientist at the Center for Applied Biomechanics at the University of Virginia. “The energy that is built into the aircraft seat is likely to be overpowered and the passengers will not be protected properly”.

     “Nor would the injury be limited to that passenger only,” Dr. Salzar said. “If a seat or a seat belt fails,”he said, “those people who are seated nearby could not be safe from the uncontrolled movements of the passenger.”

    Most complaints(投诉) about airplane seats focus on their lack of comfort and high ticket price, and whether overweight passengers should be made to buy two seats. But The New York Times' article brings up another reason to feel anxious about flying. Investigators(调查者) got in touch with the airplane seat and seat belt makers, but they refused to talk about the problem. Experts agreed that crash testing should be done. Both airplane seats and seat belts should be tested, they said.

    Fortunately, however, according to Nora Marshall, a senior adviser at the National Transportation Safety Board, the board's investigators have never seen an accident involving a commercial plane in which the weight of a passenger was a problem.

    Tang Dynasty poets sang for about three centuries in different tones. There were many famous poets living in the Tang period such as Li Bai, Du Fu, Bai Juyi and Li Shangyin. Poems of the Tang Dynasty edited in the Qing Dynasty is a collection of about 48,900 poems that were written by over 2,200 poets. But it didn't cover all the poems of the Tang Dynasty.

    During the Tang Dynasty, poems were recited when lovers walked under the moonlight. Poems were also recited when soldiers fought on the battlefield. People recited them in the open air or at temple fairs.

    In the Tang Dynasty scholars had to be poets. Their readers were not only people of high social position but also common people. Poets recited poems; women singers sang poems and other ranks of people, including old women and children, read Tang poems. This atmosphere affected foreigners who visited the country at that time. As a result, Tang poetry was introduced to some adjacent countries, like Japan and Vietnam.

    Tang poetry is a most brilliant page in the history of ancient Chinese literature. It's a miracle in the cultural history of mankind. The Tang Dynasty was a powerful empire with a vast territory. It inherited Chinese civilization that went back to ancient times, and was combined with the best of other cultures and adopted the benefits of other nations in the world. Tang poetry wasn't the only spiritual wealth created by the Tang Dynasty people. Philosophy and religion, handwriting and painting and music and dance all gained new peaks of development. Tang poetry, however, was the jewel in the crown and its greatest achievement.

    Junxi “Emma” Yang played Carnegie Hall before she got to high school. But her piano skills may have to take a back seat to her programming skill.

    According to World Journal, a US-based Chinese media organization, Emma, a 14-year-old student at the Brearley School in Manhattan, New York started coding when she was 6. Four years later, her beloved grandmother began developing Alzheimer's.

    When Emma's family moved to New York from Hong Kong in 2014, she became passionate about programming. By the time she was 10, her grandmother had already developed the disease.

    Emma got right to work. With her coding skills, she had a smartphone app created before long, designed to help people suffering from Alzheimer's.

    “Now, 'Timeless' has moved to the second stage of design,”says Emma.

    Emma hopes her grandmother can benefit from the artificial intelligence technology built into “Timeless,” the app Emma developed, to overcome her memory loss.

    Emma's newly finished app has gained support from Dr. Melissa Kramps, an Alzheimer's specialist, and from Kairo, a developer specializing in artificial intelligence.

    Timeless uses facial recognition to remind someone with Alzheimer's of vital information about the person whose photo they are looking at on their screen. It also signals whether they have just called somebody.

    The app also allows for the photo-talking, then moves to identify the people on the screen.

    The Timeless project is featured on the website Indiegogo for fundraising. Emma is hoping to raise $50,000 and work alongside professional programmers to have Timeless launched by the end of 2018.

    Many people have hailed Emma for her efforts. Bill Gates voiced his support, commending her on her bid to help bridge the gap between people with Alzheimer's and the ones they love.

    Many people don't consider their breakfast without a glass of milk. Right now, cows, buffalos, goats and sheep provide most of the world's milk. But soon, people could get milk from roaches(蟑螂).

    That isn't as crazy as it might sound. New research shows this “milk” is super-nutritious. What's more, some scientists have already begun referring to a lot of insects as source of milk.

    In 2004, Subramanian Ramaswamy started studying milk crystals found inside the roach. At the time, he was teaching biochemistry at the University of Iowa City.

    To learn more about the milk crystal from roaches, the scientists used X-rays to look at the atoms in it. The data basically revealed the chemical recipe of the roach crystal. They showed that roach milk is a “complete food”. It contains sugar with a fatty acid stuck to it. Fatty acids are the building blocks of fats. The protein in the milk is also full of essential amino(氨基的) acids, which are the building blocks of proteins. Since our bodies can't produce the “essential” ones, we need to get them from our food. And so do baby roaches.

    Barbara Stay, a biologist at Iowa University, also worked on the new study. She says the new data show that the roach milk is “three times more nutritious than cow's milk and four times more nutritious than buffalo's milk”.

    Ramaswamy would like to see roach milk turned into a protein supplement to feed hungry people. But not everyone is confident that it can be done.

    Marcel Dicke studies insects as a potential source of human food at Wageningen University in the Netherlands. Dicke says this is a “sound study”. However, in his opinion, “Extracting(提取) milk from roaches can only likely be done in a destructive way with only small quantities”. That means you'd have to raise and kill many bugs to get even tiny quantities of the milk.

    Philadelphia offers a ton of attractions that are suitable for people of every age and here are some family—friendly attractions．

    Spruce Street Harbor Park

    Spruce Street Harbor Park，one of the best urban beaches in American，is an outdoor heaven on the Delaware River waterfront．Visitors can relax in a hammock，play on the playgrounds，and play games like table tennis and giant chess．Don't miss out on the park at night，when colorful LED lights hanging from treetops make the entire area bright.

    Blue Cross RiverRink

    Offering ice skating in the winter and roller skating in the summer，Blue Cross RiverRink creates a fun，outdoor experience for the whole family．Visitors can play on the nine-hole mini-golf course during the summer，and enjoy eats and drinks from the on-site(现场的)bar and restaurant all year round．

    Sesame Place

    Big Bird，Elmo and the other stars of Sesame Street come out and play at Sesame Place，the only theme park in the nation starring the popular TV show's most lovable characters．A water park，interactive activities，parades，fireworks and shows add to the fun．

    Once Upon a Nation Storytelling Benches

    On summer days，uniformed and professional storytellers at 13 storytelling benches throughout Philadelphia's Historic District entertain visitors with true，free，three-to-five minute tales about the colonial(殖民的)era as part of Once Upon a Nation．Children can pick up a Story Flag at any storytelling bench，and then collect a star from every storyteller on their journeys．Flags with all the stars can get free rides on the Parx Liberty Carousel at Franklin Square．

Plants may tell us when they're in trouble.Thirsty tomato and tobacco plants make clicking sounds,researchers have found.The sounds are ultrasonic (超声波的),meaning they are too high-pitched for human ears to hear.But when the sounds are transformed to lower pitches,they sound like popping bubbles (爆破的泡泡).Plants also make clicks when their stems (茎) are cut.

"It's not like the plants are screaming," says Lilach Hadany,an evolutionary biologist working at Tel Aviv University in Israel."Plants may not mean to make these noises.We've shown only that plants create informative sounds."

Hadany and her colleagues first heard the clicks when they set microphones next to plants on tables in a lab.The microphones caught some noises.But the researchers needed to make sure that the clicking was coming from the plants.So,the scientists placed plants inside soundproof boxes in the basement,far from the noise of the lab.There,microphones picked up ultrasonic pops from thirsty tomato plants.Though it was outside humans' hearing range,the clicking made by plants was about as loud as a normal conversation.

Cut tomato plants and dry or cut tobacco plants clicked,too.But plants that had enough water or hadn't been cut stayed mostly quiet.Wheat,corn and grapevines also made sounds when stressed out.

The researchers don't yet know why plants click.Bubbles forming and then popping inside plant tissues that transport water might make the noises.But however they happen,pops from crops could help farmers,the researchers suggest.Microphones,for example,could monitor fields or greenhouses to detect when plants need to be irrigated (灌溉).

Hadany wonders whether other plants and insects already tune into plant pops.Other studies have suggested that plants respond to sounds.And animals from pests (害虫),moths to mice can hear in the range of the ultrasonic clicks.Sounds made by plants could be heard from around five meters away.Hadany's team is now studying what the living things near the plants will do after hearing the sounds.