An artist in Oakland, California is using his skills to help the homeless. Greg Kloehn builds very small shelters that make life on the streets a little more comfortable. The structures offer the homeless some safety and protection from bad weather. Each little house also has wheels on the bottom so it can go wherever its owner goes.

    Greg Kloehn has given away at least 20 tiny houses. Several are on the roadside near an active railroad. On a recent day, Mr. Kloehn stops at one to visit Oscar Young. The two men hug. Inside his little shelter Mr. Young gets relief from cold nights on the streets. Mr. Kloehn also visits Sweet-Pea, another friend who also lives in one of the little homes the artist built. She says it keeps her safe and protects her belongings.

    In the mornings, Mr. Kloehn searches the streets for building materials. He gathers what he can and takes it to his studio. There, he puts the houses together. Empty coffee bags become roof material. A washing machine door and refrigerator part become windows. Nails, screws and the sticky glue hold all the pieces together. The artist also attaches a small electrical device to the house. The device is powered by the sun.

    Some of the people living on the streets once had normal houses of their own. But some of the people say they have learned to live with less and they are thankful to that man.

    Mr. Kloehn says his work is not a social project. He says he is just someone using his skills to help his homeless neighbors.

The Square

    Jack Dorsey, the co-inventor of Twitter, is promoting his latest invention called the Square. The square is a small plug-in attachment to your mobile phone that allows you to receive credit card payments.

    The idea starting from Dorsey's friend Jim McKelvey who was unable to sell some glass work to a customer because he couldn't accept a particular card being used.

    Accepting credit card payments for something you're selling isn't always easy, especially if you are mobile like a tradesman, or delivery service at a trade show.

    This latest invention uses a small scanner that plugs into the audio input item on a mobile device. It reads information on a credit card when it is swiped(刷卡). The information is not stored on the device but sent over secure channels to banks. It basically makes any mobile phone a cash register for accepting card payments.

    As a payer, you receive a receipt via email that can be instantly accessed securely online. You can also use a text message to authorize payment in real time. Retailers can create a payer account for their customers which speeds the payment process. For example, a cardholder can assign a photo to their card so their photo will appear on the phone for visual identity confirmation. Mobile devices with touch screens will also allow you to sign for goods.

    There are no contracts, monthly fees, or hidden costs to accept card payments using Square and it is expected the plug-in attachment will also be free of charge.

    As with Twitter, it's expected that Dorsey will direct the company based upon feedback from users. Square Inc. has offices in San Francisco, Saint Louis and New York and is currently beta testing the invention with retailers in the United States.

    In China, Double Eleven Shopping Day is approaching. And there is a similar case in the United States—Black Friday. It has been regarded as the beginning of the holiday shopping season. Although it's not an official holiday, millions of employers give their employees the day off, and many people use that day to get a jump-start on their holiday shopping. A similar day in Canada and Great Britain is called "Boxing Day".

    Black Friday has become somewhat of a marketing sensation in recent years. Since 2005, it has been the busiest shopping day of the year. To lure shoppers, retailers (零售商) routinely open their doors as early as 4 a.m. and offer special sales and promotions to the shoppers that arrive early. Some of the special deals offered by stores are only available in limited quantities. That is why some shoppers intent on getting the best deals often camp out in front of stores overnight so that they'll be the first in line when the doors open.

    But why is it called Black Friday? Historians believe the name started in Philadelphia in the mid-1960s. Bus drivers and police used "Black Friday" to describe the heavy traffic that would block city streets the day after Thanksgiving as shoppers headed to the stores.

    Businesses, however, didn't like the negative tone associated with the "Black Friday" name. In the early 1980s, a more positive explanation of the name began to circulate. According to this alternative explanation, Black Friday is the day when retailers finally begin to turn a profit for the year. In accounting terms (会计行业), operating at a loss is called being "in the red" because accountants traditionally used red ink to show negative amounts. Positive amounts were usually shown in black ink. Thus, being "in the black" is a good thing because it means stores are operating at a profit.

    Recently, for those who are too busy to shop on Black Friday or who just don't want to fight the crowds, the Monday following Black Friday has become known as Cyber Monday (网络星期一) for the many online deals.

    A video of a three-year-old girl being kicked by her own mother during a photo shot went viral (疯狂传播) on Thursday, indicating China's under per forma nee in regulating the emerging child modeling industry.

    The girl, known as Niu Niu, was physically abused by her mother in several videos. The videos have annoyed Chinese media and Internet users alike. Many netizens and scholars call for local authorities to carry out further investigations into possible child abuse.

    In response to the public outcry (强烈抗议), Niu Niu's mother issued an apology via Sina Wei bo on Thursday, condemning accusations of abuse. She noted that she was merely guiding her daughter for better shots and the girl is well looked after.

    Despite her apology, many E-shops which used Niu Niu's images for brand promotion have canceled their cooperation with the mother, while over 110 well-known child garment shops on Taobao have signed up for a campaign to provide better protection for child models.

    "It is necessary to adopt comprehensive laws and regulations to further protect the kids, preventing their parents and companies from exploiting (利用) them," Fang Zhiqing, a lawyer and child protection expert, said.

    Niu Niu is not alone. In Zhili, a small town in Zhejiang province, thousands of children from across China are taken here by their parents to seize the chance of fame. With a population of 450,000. Zhili has over 13,000 manufacturers of child clothing. In 2017, the town earned over 7 billion yuan by selling do thing for children online, thus providing opportunities for child models.

    "China's current advertisement law isn't workable when it comes to the industry of child modeling, as it lacks clear supervision measures and clear legal punishment." Fang added. "It is important to issue new laws which regulate child modeling."

The Mona Lisa is the famous Leonardo da Vinci painting of a woman with a mysterious smile. This week, the painting gave up a secret.

Scientists used X-rays to examine the chemical organization of an extremely small part of the more than 500-year-old painting. The researchers discovered a technique Leonardo used in the work. A team in France and Britain discovered an oil paint used for the Mona Lisa was a special, new chemical mixture. It suggests that the Italian artist may have been in an experimental mood when he set to work on the painting early in the 16th century.

"He was someone who loved to experiment, and each of his paintings is completely different technically," said Victor Gonzalez. He is the study's lead writer. "In this case, it's interesting to see that indeed there is a specific technique for the ground layer of the Mona Lisa," he said in an interview with The Associated Press. Specifically, the researchers found a rare compound, plumbonacrite (水蛭石), in Leonardo's first layer of paint. The discovery, Gonzalez said, proved that da Vinci most likely used lead oxide to thicken and help dry his paint.

The scientists looked into its atomic structure using X-rays in a synchrotron (同步加速器). The machine moves particles at close to the speed of light, permitting researchers to look deeper into the paint structure. "Plumbonacrite is really a fingerprint of his recipe," Gonzalez said. "It's the first time we can actually chemically prove it."

Dutch artist Rembrandt may have used a similar mixture when he was painting in the 17th century. Gonzalez and other researchers have found plumbonacrite in his work, too. "It also tells us that those recipes were passed on for centuries," Gonzalez said. "It was a very good recipe."

But the Mona Lisa and additional works by Leonardo still have other secrets to tell. "There are plenty, plenty more things to discover," Gonzalez said. "What we are saying is just a little brick more in the knowledge."

A 15-year-old Colorado high school student and young scientist who has used artificial intelligence (AI) and created apps to address polluted drinking water, drug addiction and other social problems has been named Time Magazine's first-ever "Kid of the Year". 

Rao told The Associated Press in an interview from her home that the prize is nothing that I could have ever imagined. And I'm so grateful and just so excited that we're really taking a look at the upcoming generation and our generation, since the future is in our hands. 

Time said Rao stood out for creating a global community of young innovators and inspiring them to pursue their goals. Rao insisted that starting out small doesn't matter, as long as you're passionate about it. 

She told Time contributing editor Angelina Jolie in an interview that her science pursuits started early as a way to improve social conditions. The drinking water crisis in Flint, Michigan, inspired her work to develop a way to detect pollutants and send those results to a mobile phone, she said. 

"I was like 10 when I told my parents that I wanted to research carbon nanotube sensor technology at the Denver Water quality research lab, and my mum was like, A what?" Rao told Jolie. She said that work is going to be in our generation's hands pretty soon. "So if no one else is gonna do it, I'm gonna do it. "

In a world where science is increasingly questioned or challenged, Rao insisted that its pursuit is an act of kindness, the best way that a younger generation can better the world. 

"We have science in everything we're involved in, and I think that's the biggest thing to put out there, that science is cool, innovating is cool, and anybody can be an innovator. " Rao said, "Anybody can do science. "