Cold weather has a great effect on how our minds and our bodies work. Maybe that is why there are so many expressions that use the word cold. For centuries, the body's blood has been linked closely with the emotions. People who show no human emotions or feelings, for example, are said to be cold –blooded. Cold –blooded people act in merciless ways. They may do cruel things to others, and not by accident. For example, a newspaper says the police are searching for a cold-blooded killer. The killer murdered someone, not in self-defense. He seemed to kill with no emotion.

    Cold can affect other parts of the body, the feet, for example. Heavy socks can warm your feet, if your feet are really cold. But there is an expression—to get cold feet –that has nothing to do with cold or your feet. The expression means being afraid to do something you had decided to do. For example, you agree to be president of an organization. But then you learn that all the other officers have given up the position. All the work of the organization will be your responsibility. You are likely to get cold feet about being president when you understand the situation.

    Cold can also affect your shoulder. You give someone the cold shoulder when you refuse to speak to them. You treat them in a distant, cold way. The expression probably comes from the physical act of turning your back toward someone, instead of speaking to him face-to-face. You may give a cold shoulder to a friend who has not kept a promise he made to you. Or, to someone who has lied about you to others.

    A cold fish is not a fish. It is a person. But it is a person who is unfriendly, unemotional and shows no love or warmth. A cold fish does not offer much of himself to anyone.

    Out in the cold is an expression often heard. It means not getting something that everybody else got. A person might say that everybody but him got a pay raise. He was left out in the cold. And it is not a pleasant place to be.

    Living among trees, plants and flowers can fill your life with beauty. And if you are a woman, it can also help you live longer. Researchers found that women who live in homes surrounded by plants appear to have lower death rates than women who live in areas with fewer plants.

    Researchers at Harvard University's T.H. Chan School of Public Health reported the finding. They looked at the information from one of the largest and oldest investigations of the women's health: the Nurse's Health Study. It began 40 years ago. It now has information on nearly 200,000 women.

    For the new study, the team looked at the death rates of more than 100,000 women between the years 2000 and 2008. Then the researchers compared the death rates of these women to the plants around their homes. The researchers also considered other things, such as the age of the women, money they earn and race. They also looked at whether or not the women smoked.

    The study found that the death rate among women who lived in the greenest spaces was 12% lower than those from the least green areas. The researchers were surprised to find such a strong connection between high vegetation levels and low death rates.

    The study suggested that living among trees, flowers and other plants lowered levels of depression. Researchers said women in greener areas spent more time with other people and exercised more. It is common knowledge that plants can help the environment in many ways. The new finding also suggested ways to the government and the city planners to grow even healthier living areas.

    As free as they make us, mobile phones still need to stay close to a power source. Soon that may change with "green" power.

    Three Chilean students got the idea for a plant-powered device(装置) to charge their cellphones, while sitting in their school's outdoor courtyard during a break from exams, with dead mobile phones. Then, one of them had an "aha" moment.

    “It occurred to Camila to say about plants,” said inventor Evelyn Aravena. “'Why don't you have a socket, if there are so many plants? 'After that, we thought, 'why don't they have a charging outlet? Because there are so many plants and living things that have the potential to produce energy, why not?'”

    Their invention—a small biological circuit called E-Kaia—uses the energy plants to produce during photosynthesis(光合作用). A plant uses only a small part of that energy and the rest goes into the soil, and that's where the E-Kaia collects it. The device plugs into the ground and then into your phone.

    "It's the most amazing project I've ever seen in my life, plain and simple. They brought this original model, and it worked — and that's when it all changed, at least from my personal point of view and I began to support them." said Mauricio Cifuentes.

    The device solved two problems for the engineering students — they needed an idea for a class project, and an outlet to plug in their phones.

    "Looking for a place to charge the notebook, which had no power, and the mobile phones, we weren't able to find anything because all the other students were in the same state of madness trying to find a place to charge their devices," said Aravena.

    But plants are everywhere, and the bio－circuit makes the best of their excess(过多的) power.

    The E-Kaia doesn't carry much charge but it's powerful enough to completely recharge a mobile phone in less than two hours.

    The student inventors have applied for patents on their technology, and expect the E-Kaia to go on sale in December 2016.

    Andrew Jackson has been sitting pretty on the $20 bill for 87 years. Is it time to bring some new blood to the banknote?

    The non-profit organization called Women on 20s is campaigning to put a woman's face on American money. Barbara Ortiz Howard, the company's founder, would like to see a woman on the $20 bill by 2020.That year marks the 100-year anniversary of the 19th Amendment to the United States Constitution, which gave women the right to vote.

    Howard got the idea when she realized that her daughter had no everyday reminders of famous women in history. She asked her friend Susan Ades Stone, a journalist, to join her cause. “Part of the aim is to educate as many people as possible about as many women as possible,” Ades says. “We want to see how many people we can reach.”

    American money values the successes of former presidents and founding fathers. Currently, there are only two women on money: Susan B. Anthony is the face of the rare dollar coin, and Sacagawea can be seen on the gold dollar coin. There are no women on paper bills.

    With help from writers and historians, Howard and Stone came up with a voting list featuring 15 important women. Ades says there is a standard for choosing candidates. They look at the women's contributions to our world, and at what challenges they faced.

    More than 72,000 people have voted so far in the poll. Ades says the competition has narrowed to a “very close race”, but won't say who's in the lead. After two rounds of voting, Women on 20s will send their campaign to the White House for consideration. The final decision is up to the Treasury Secretary, Jack Lew. Lew is unlikely to make a change without the president's approval. But last year, when a little girl asked the president why there aren't any women on US currency, he said that adding a woman is a “pretty good idea”.

    A few months after Wu Xingu was congratulated by teachers for graduating from the university, the 23-year-old has been making his dream of relieving tens of thousands of teachers in China from drowning in marking papers(改卷) a reality.

    Yitiku, an online software system based on Wu's idea, eases the workload of teachers by doing many of the functions that they did, such as selecting the test questions, forming an exam paper, and preparing exercises for the students.

    The features of Yitiku may sound quite simple, but this idea won his company millions of dollars from China's Internet giant Tencent in January. The unexpectedly successful fund raising story became a popular conversation starter among the people in the education business.

    "I can say it's quite an achievement for me and our company. As far as I know, I'm the first CEO born after 1990s that Tencent has invested (投资) in, and we are the first online education company they have invested in." Wu Xingyu told China Daily.

Different from other online companies that treat students as clients (客户), Yitiku has chosen teachers as their focus. "We make the work of teachers easy. Usually it takes two to three hours for them to prepare a new exam paper. Now it's just three clicks." said Wu. He is quite satisfied with the major feature of the software.

    Sitting in his 10-square-meter office in Zhonguancun, a hub of innovation (创新) in Beijing, Wu looks confident and chatty when talking about his business. His fast-speed answers give people an impression that he has years of experience in the online education sector. The fact is that he had been putting most of attention in directing courses at an art college until about a year ago.

    More than 20 years ago, a skeleton called Little Foot turned up in a South African cave. The nearly complete skeleton was a member of the human family. Now researchers have freed most of the skeleton from its stony shell and analyzed the fossils (化石) and they say 3.67-million-years-old Little Foot belonged to a unique species.

    Researcher Ronald Clarke and his colleagues think Little Foot belonged to A. Prometheus (普罗米修斯南猿). Clarke works at the university of the Witwatersrand in Johannesburg South Africa. He studies fossilized humans and our relatives. Their foundings, published in four papers, have suggested the species A.Prometheus might have existed. Clarke has believed in that species for more than a decade, he found the first Little Foot's remains in a storage box of fossils in 1994. People began digging out the rest of the skeleton in 1997.

    Many other researchers instead argue that Little Foot likely belonged to a different species, which is known as A.africanus (南方古猿非洲种). Researcher Raymond Dart first identified A.africanus in 1924. He was studying the skull (头颅骨) of an ancient youngster called the Taung Child. Since then, people have turned up hundreds more A. africanus fossils in South African caves. Those include Sterkfontein, where Little Foot was found.

    The braincase is the part of the skull that holds the brain. And researchers found a partial braincase that Dart thought belonged to a different species in Makapansgat, one of those other caves. In 1948, Dart called this other species A. Prometheus, but he changed his mind after 1955. Instead, he said that braincase and another fossil at Makapansgat belonged to A.africanus. There was no A. Prometheus after all, he concluded.

    Clarke and his colleagues want to bring back the rejected species. They say Little Foot's distinctive skeleton, an adult female that is at least 90 percent complete, is solid evidence for it.