It may sound strange, but cutting down a real tree for Christmas is actually greener than going with the artificial kind, one scientist says.

    “It is a little confusing to people,” said Clint Springer, a biologist at Saint Joseph's University in Philadelphia. Because of concerns over deforestation（砍伐森林）around the world, many people naturally worry that buying a real tree might contribute to that problem. But most Christmas trees for sale these days are grown not in the forest but on tree farms for the purpose of being cut.

    Moreover, from the viewpoint of greenhouse gases, real trees are “the obvious choice”. Live trees actively release oxygen as they grow, and meanwhile remove carbon dioxide from the atmosphere. After they have been cut and Christmas is over, they're usually cut into smaller pieces for mulch（覆盖物）. As mulch, the bits of trees very slowly release carbon dioxide back into the atmosphere. So in the end, a real Christmas tree is carbon neutral, putting the same amount of carbon dioxide back into the air as it took out (although much more slowly).

    The tree farms that grow the trees also replant after the trees are cut.  Artificial trees, on the other hand, don't come out even in the carbon balance. Petroleum（石油）is used to make the plastics in artificial trees and lots of carbon dioxide-creating energy is required to make and transport them. Because these trees just end up in the places where waste is buried under the ground after use, “those greenhouse gases are lost forever,” Springer said.

    There are many places to go on safari in Africa, but riding a horse through the flooded waters of Botswana's Okavango Delta must rank as one of the world's most exciting wildlife journeys.

    Several safari camps operate as the base for this adventure, providing unique rides twice a day to explore deep into the delta. The camps have excellent horses, professional guides and lots of support workers. They have a reputation for providing a great riding experience.

    The morning ride, when the guides take you to beautiful, shallow lakes full of water lilies, tends to be more active. It is unlike any other riding experience. With rainbows forming in the splashing water around you and the sound of huge drops of water bouncing off your body and face. It is truly exciting. You are very likely to come across large wild animals, too. On horseback it is possible to get quite close to elephants, giraffes and many other animals. The sense of excitement and tension levels rise suddenly though, as does your heart rate, as you move closer to them.

    In the evening, rides are usually at a more relaxed and unhurried pace. With golden light streaming across the grassy delta and the animals coming out to eat and drink. Sedate though they are, rides at this time of day are still very impressive. As the sun's rays pass through the dust kicked up by the horses, the romance of Africa comes to life.

    Back at the camp you can kick off your boots and enjoy excellent food and wine. Looking back on your day, you will find it hard to deny that a horseback Safari is as close as you will ever come to answering the call of the wild.

    One of the latest trends（趋势） in American Childcare is Chinese au pairs. Au Pair in Stamford, Conn, for example, has got increasing numbers of request for Chinese au pairs from aero to around 4, 000 since 2004. And that's true all across the country.

    "I thought it would be useful for him to learn Chinese at an early age" Joseph Stocke, the managing director of a company, says of his 2-year old son. "I would at least like to give him the chance to use the language in the future, " After only six months of being cared by 25-year-old woman from China, the boy can already understand basic Chinese daily expressions, his dad says.

    Li Drake, a Chinese native raising two children in Minnesota with an American husband, had another reason for looking for an au pair from China. She didn't want her children to miss out on their roots. " Because I am Chinese, my husband and I wanted the children to keep exposed to(接触) the language and culture." she says.

    "Staying with a native speaker is better for children than simply sitting in a classroom," says Suzanne Flynn, a professor in language education of Children. "But parents must understand that just one year with au pair is unlikely to produce wonders. Complete mastery demands continued learning until the age of 10 or 12. "

    The popularity if au pairs from China has been strengthened by the increasing numbers of American parents who want their children who want their children to learn Chinese. It is expected that American demand for au pairs will continue to rise in the next few years.

    Do you like to flaunt your expensive items? You could find yourself without friends! Scientists prove that expensive status symbols make you look less socially attractive.

    Items such as a fancy car and a Rolex watch are often thought to increase our social standing and often come with a high price tag(标签). According to the latest research, however, it has the opposite effect and people would prefer to be friends with someone who places less value on material objects.

    "Often we think that status symbols will make us look more socially attractive to others, "says Stephen Garcia, the study's lead author from the University of Michigan. He adds, "However, our research suggests that these status signals actually make us look less socially attractive.

    The researchers conducted six studies which assessed how people presented themselves and how people viewed strangers. People who chose to wear higher status items tended to get a negative response, but people wanted to be friends with people who preferred lower status symbols.

    The study took the role of the luxury item to see if it was possible that the expensive item itself played a part in people's reactions. The definition of a status symbol changed based on a person's socioeconomic status, but the same effect of keeping off potential friends was seen regardless of social position.

    "At a social level, we may be wasting billions of dollars on expensive status symbols that finally keep others from wanting to associate with us, "says Kimberlee Weaver Livnat at the University of Haifa. She says, "And to the extent that close friendships are important to well-being, we may be unintentionally hurting ourselves."

    However, Patricia Chen of the National University of Singapore said this does not necessarily mean status symbols are a bad thing. She says, "Our findings right now only apply to the formation of new friendships, Status symbols may be beneficial at other times and in other settings, such as when trying to establish new business contacts."

    Traditional Chinese Medicine (TCM) needs to prove its worth through rigorous clinical trials, according to the head of one of China's largest herbal remedy companies, as a contentious new law to boost the $40bn sector comes into effect.

    Traditional Chinese Medicine is estimated by analysts to account for a third of sales in China's $117bn pharmaceutical (药学) market, the world's second largest. But most of those sales are of relatively cheap over-the-counter drugs, with many Chinese hospital doctors unwilling to prescribe TCM remedies because of the lack of evidence for their effectiveness.

    China's first law promising equal status for TCM and western medicine in the country's state-dominated healthcare system comes into effect this weekend. Provisions include encouragement for hospitals to set up TCM centres, and a licensing system for practitioners (从业者). "This law is very important for securing the status of TCM," said Wu Yiling, chairman of Yiling Pharmaceutical, a company that makes herbal remedies based on traditional recipes in the northern province of Hebei.

    Listed in Shenzhen, Wu Yiling has a market capitalization of RMB 20.7bn ($3bn). Mr Wu, the son of a herbal practitioner, controls a family fortune of $1.6bn, according to the Hurun Rich List.

    Mr Wu is both a supporter of the nature of Qi—the mystical energy force that provides the basis for much of TCM theory—and the clinical trials vital to western pharmaceutical companies. "TCM needs to develop using modern research methods," he said.

    For instance, researchers from Peking and Cardiff Universities tested the health benefits of Yiling's herbal medicine Yangzheng Xiaoji, publishing papers in the International Journal of Oncology that showed the drug can slow the growth of cancer tumours. "The theory and recipe is TCM, but in practice the evaluation of our medicines is carried out according to western evidence-based methods," Mr Wu said.

    Analysts say such tests can help gain support from doubtful hospital doctors and boost prescriptions. "Doctors need strong evidence that drugs definitely work," said Serena Shao, healthcare analyst at brokerage CLSA. "Some of these companies are currently doing clinical trials, and getting proof that their drugs have the same efficacy (功效) as chemical drugs. That's the way to go." she added.

    The TCM law has been greeted with doubt from China's western-schooled medical establishment, which points to a lack of rigorous training for TCM doctors, and a recent series of shocking events involving herbal injections believed to have been harmful. "Officials will try and encourage TCM, but also will be very cautious about what kinds of TCM they use in hospitals," added Ms Shao.

Ivan Pavlov was a Russian physiologist (生理学家) best known for his discovery of classical conditioning (经典条件反射). During his studies on the digestive systems of dogs, Pavlov found that the animals salivated (流口水) naturally upon the presentation of food. However, he also noticed that the animals began to salivate whenever they saw the white lab coat of an experimental assistant. By associating the presentation of food with the lab assistant, he finally found that a dog would salivate to the presence of a stimulus (刺激物) other than food. He called this response a conditional reflex.

Ivan Pavlov was born in a small village in Ryazan. Russia, where his father was the village minister. His earliest studies were focused on theology (神学), but reading Charles Darwin's On the Origin of Species had a powerful influence on his future interests. He soon stopped his religious studies and devoted himself to the study of science at the University of Saint Petersburg. Pavlov's interests were the study of physiology and natural sciences. He helped found the Department of Physiology at the Institute of Experimental Medicine and continued to manage the program for the next 45 years.

Pavlov received much praise for his work. He worked in the Russian Academy of Science and won the 1904 Nobel Prize in Physiology. The Soviet government also offered lots of support for Pavlov's work, and the Soviet Union soon became a leading center of research on physiology. While Ivan Pavlov was not a psychologist, and reportedly disliked the field of psychology, his work had a major influence on the field, particularly on the development of behaviorism. His discovery and research on reflexes influenced the growing behaviorist movement. and Pavlov's discovery had a major influence on many thinkers, such as John B. Watson.