【推荐3】From the moon to Mars, scientists have been hunting for alien life in the solar system for decades.

However, Venus was not regarded as an ideal place because of its hot temperature and dry atmosphere. But a recent discovery of traces of a gas in the clouds of Venus has excited astronomers, as it may serve as a potential sign of life.

On Sept 14, the Royal Astronomical Society of Canada announced that scientists have detected phosphine (磷化氢) in the clouds of Venus. Phosphine is a colorless, toxic gas that has an odor of garlic. Though toxic, it is viewed as a possible sign of life because on Earth the gas is made by microorganisms that live in oxygen-free environments.

“I was very surprised, stunned, in fact.” astronomer Jane Greaves of Cardiff University in Wales and lead author of the research, told MSN. “There is a chance that we have detected some kind of living organism in the clouds of Venus.”

This layer of clouds is about 48 kilometers above the Venus surface, with its temperature ranging from 30 to 200 degrees Fahrenheit (about -1 to 93℃). Scientists have inferred that if life exists on Venus, this cloud deck is likely the only place where it would survive.

Scientists went through every possibility that could have led to the formation of phosphine gas in Venus’ clouds, including volcanoes, lightning strikes, small meteorites (陨石) falling into the atmosphere. But they ruled all of them out. It was concluded that there is no explanation for the existence of this gas in Venus’ clouds, other than the presence of life, USA Today reported.

Although the detection of phosphine is not strong evidence for life, this finding is great enough to change scientists’ view on Venus, which is thought to be a completely inhospitable planet.

What signs of life we looking for?

(1). Liquid water: It can dissolve a huge range of molecules needed for life and facilitate their chemical reactions.

(2). Mild temperatures: Temperatures higher than 122 ℃ will destroy most complex organic molecules, and make it almost impossible for carbon-based life to form.

【推荐1】In between all the measures to battle the severe air pollution in Delhi, India, there’s one more option — a bar that has “pure air”.

Founded by Aryavir Kumar, Oxy Pure, Delhi’s first-ever oxygen bar, offers 15 minutes of 80-90 percent pure oxygen, costing Rs 299 ($4.2). Customers are given a lightweight tube for oxygen intake. The device (装置) is placed near the customer’s nostrils (鼻孔) through which they are advised to breathe in the oxygen.

The bar also offers its customers several aromas (气味) to go with oxygen, including lemongrass, cherry and more. According to the aroma people choose, each session promises to improve sleep patterns and digestion, cure headaches, and even claims to work as a treatment for depression.

Bonny Irengbam, a senior sales assistant at the bar, said, “Some people, who try it for the first time, will feel relaxed and fresh. But only people who do this regularly will get real benefits. By regularly, I mean once or twice a month. We don’t encourage back-to-back sessions, as increased levels of oxygen in the body can make a person dizzy.”

Dr. Rajesh Chawla, a senior doctor at the Indraprastha Apollo Hospital, said, “Even if you breathe in the so-called pure oxygen for two hours in a day, you will go back to breathing the polluted air for the rest of the 22 hours. The concept is purely money-driven.”

Recalling the first few months of the bar, Irengbam admitted that people were sceptical. “Many people criticised, saying we were selling air. Others were simply scared to breathe through the tube.”

Irengbam said the bar saw a significant rise in the number of customers two to three days after Diwali, an Indian festival mainly celebrated by fireworks and lights, as the pollution levels were high.

【推荐2】Imagine possessing something that you loved so much. Imagine what it would feel like if you lost it. While that item may be something as simple as a doll, you would still feel very upset, but you could replace it with a new one. Now imagine losing something that you depend on for survival and cannot be replaced. That is what it would be like if we lost the natural environment around us.

Firstly, I believe the environment should be preserved because it supports human life. One of the largest examples is that we get all of our food and drinks in the environment. If the environment were to be destroyed beyond revival, then the human race would be over in months. Scientists have yet to find another planet with similar conditions to the Earth, and if it’s found, we don’t have the technology to get to that planet on time.

Secondly, I believe that the environment serves as an amazing educational tool for students. When I was in second grade, I had an absolute interest in animals. When we had a field trip to the Daggerwing Nature Center, I was very excited. When we got there, I could hardly believe what I was seeing. There was a bridge to get to the main building, and under the bridge was a small swamp(沼泽) with turtles, fish, and my personal favorite, alligators. I was so surprised that I almost ran into the tour guide. We walked into the building and saw various animals in their habitats. I was so inspired by this visit. Six years later, I have taken an animal behavior class for three weeks. Meeting by chance with the environment can inspire people, and if preserved it will continue to inspire people.

In conclusion, the environment is so valuable because it can’t be replaced, keeps us alive, and serves as a great educational tool.

【推荐2】While Jennifer was at home taking an online exam for her business law class, a monitor（监控器）a few hundred miles away was watching her every move.

Using a web camera equipped in Jennifer's Los Angeles apartment, the monitor in Phoenix tracked how frequently her eyes moved from the computer screen and listened for the secret sounds of a possible helper in the room. Her Internet access was locked remotely to prevent Internet searches, and her typing style was analyzed to make sure she was who she said she was: Did she enter her student number at the same speed as she had in the past？ Or was she slowing down？

In the battle against cheating, this is the cutting edge and a key to encourage honesty in the booming field of online education. This technology gives trust to the entire system, to the institution and to online education in general. Only with solid measures against cheating, experts say, can Internet universities show that their exams and diplomas are valid — that students haven't searched the Internet to get the right answers.

Although online classes have existed for more than a decade, the concern over cheating has become sharper in the last year with the growth of "open online courses". Private colleges, public universities and corporations are jumping into the online education field, spending millions of dollars to attract potential students, while also taking steps to help guarantee honesty at a distance.

Aside from the web cameras, a number of other high-tech methods are becoming increasingly popular. Among them are programs that check students’ identities using personal information, such as the telephone numbers they once used.

Other programs can produce unique exams by drawing on a large list of questions and can recognize possible cheaters by analyzing whether difficult test questions are answered at the same speed as easy ones. As in many university classes, term papers are scanned against some large Internet data banks for cheating.

【推荐3】With only about 1, 000 pandas left in the world, China is desperately trying to clone(克隆) the animal and save the endangered species(物种).That's similar to what Texas A&M University researchers have been undertaking(负责) for the past five years in a project called “Noah's Ark”.   

Noah's Ark is aimed at collecting eggs, embryos(胚胎), semen and DNA of endangered animals and storing them in liquid nitrogen(氮).If certain species should become extinct, Dr. Duane Kraemer, a professor in Texas A&M'S College of Veterinary Medicine, says there would be enough of the basic building blocks to reintroduce the species in the future.

It is estimated that as many as 2, 000 species of mammals, birds and reptiles will become extinct in over 100 years. The panda, native only to China, is in danger of becoming extinct in the next 25 years.

Chinese scientists said they grew an embryo introducing cells from a dead female panda into the egg cells of a Japanese white rabbit. They are now trying to implant the embryo into a host animal.

The entire procedure(过程) could take from three to five years to complete.

“The nuclear transfer(核子移植) of one species to another is not easy, and the lack of available(capable of being used) panda eggs could be a major problem,” Kraemer believes. “They will probably have to do several hundred transfers to result in one pregnancy (having a baby).It takes a long time and it's difficult, but this could be groundbreaking science if it works. They are certainly not putting any live pandas at risk, so it is worth the effort,” adds Kraemer, who is one of the leaders of the Project at Texas A&M, the first­ever attempt at cloning a dog.

“They are trying to do something that's never been done, and this is very similar to our work in Noah's Ark. We're both trying to save animals that face extinction. I certainly appreciate their effort and there's a lot we can learn from what they are attempting to do. It's a research that is very much needed. ”