Have you ever wondered when dogs first became “man's best friend” and the world's favourite pet? If you have then you're not alone. When and where dogs first began living side-side with humans are questions that have stirred hot debate among scientists. There are a few hard facts that all agree on. These include that dogs were once wolves and they were the first animal to be domesticated(驯养) by humans. They came into lives some 15000 years ago, before the dawn of agriculture.

    Beyond that, there is little agreement. The earliest bones found that are unquestionable dogs and not wolves date from 14,000 years ago. However, 30,000-year-old skulls have been discovered in France and Belgium that are not pure wolf and some scientists think could be dogs.

    With such puzzling evidence, many scientists are now turning to DNA to find out when and where dogs were first domesticated. In one research project, tens of thousands of blood samples have been taken from street dogs around the world. The plan is to compare them with those of wolves. It's even possible to analyse DNA from ancient bones. Tiny pieces of the 30,000-year-old skulls mentioned earlier are currently being studied, and another DNA study has already shown that ancient dogs preserved in the Alaskan ice-fields evolved from Asian wolves, not American ones.

    Indeed, the ancient DNA may turn out to be more informative than the DNA of living dogs. Because dogs have accompanied humans around the world for thousands of years, their current distribution may tell us very little of their origins. This is why different groups of scientists believe that dogs variously originated in eastern Asia, Mongolia, Siberia, Europe or Africa.

    But why were the animals domesticated in the first place? The most recent theory is that dogs domesticated themselves, initially living in and around our ancient villages to eat any food thrown out. Today, this is a way of life still shared by three -quarters of a billion unowned dogs worldwide.

    Have you ever picked a job based on the fact that you were good at it but later found it made you feel very uncomfortable over time? When you select your career, there's a whole lot more to it than assessing your skills and matching them with a particular position. If you ignore your personality, it will hurt you long-term regardless of your skills or the job's pay. There are several areas of your personality that you need to consider to help you find a good job. Here are a few of those main areas;

1) Do you prefer working alone or with other people?

    There are isolating jobs that will drive an outgoing person crazy and also interactive jobs that will make a shy person uneasy. Most people are not extremes in either direction but do have a tendency that they prefer. There are also positions that are sometimes a combination of the two, which may be best for someone in the middle who adapts easily to either situation.

2) How do you handle change?

    Most jobs these days have some elements of change to them, but some are more than others. If you need stability in your life, you may need a job where the changes don't happen so often. Other people would be bored of the same daily routine.

3) Do you enjoy working with computers？

    I do see this as a kind of personality characteristic. There are people who are happy to spend more than 40 hours a week on a computer, while there are others who need a lot of human interaction throughout the day. Again, these are extremes and you'll likely find a lot of positions somewhere in the middle as well.

4) What type of work environment do you enjoy？

    This can range from being in a large building with a lot of people you won't know immediately to a smaller setting where you'll get to know almost all the people there fairly quickly.

5) How do you like to get paid?

    Some people are motivated by the pay they get, while others feel too stressed to be like that. The variety of payment designs in the sales industry is a typical example for this.

    Anyway, these are a great starting point for you. I've seen it over and over again with people that they make more money over time when they do something they love. It may take you a little longer, but making a move to do what you have a passion for can change the course of your life for the better.

     Scientists have found living organisms trapped in crystals(晶体) that could be 50,000 years old.

     The organisms were found in a hot, but beautiful cave system in Naica, Mexico. These ancient life forms can be seen only with a microscope. Penelope Boston, who leads the Astrobiology Institute at NASA, the space agency of the United States, says the ancient microbes(微生物) were able to live by eating minerals such as iron.

     She spoke about the discovery recently at a meeting of the American Association for the Advancement of Science. If the findings are confirmed, they will show how microbes can survive in extreme conditions. Forty different kinds of microbes and some viruses were found in the underground area. The genetic structures of these organisms are 10 percent different from those of their nearest relatives.

     The caves in Naica are 800 kilometers deep. They were once used for mining lead. Before the miners began working in the caves, the area was separated from the surface and the outside world. Some of the caves are as big as the large religious centers built during Europe's Middle Ages. There are crystals covering the walls. The caves are so hot that scientists must wear special clothing to keep cool. The clothing keeps the crystals safe from human germs（病菌）or other damage. Boston said the researchers could only work for about 20 minutes at a time before they had to go to a room that was 38 degrees Celsius to cool down.

     NASA officials would not let Boston share her findings with scientific experts before last week's announcement. So scientists could not say much about the findings. But Norine Noonan, a biologist with the University of South Florida, said she believed them. "Why are we surprised?" Noonan asked. "As a biologist, I would say life on Earth is extremely tough and extremely colorful."

     Boston is also studying microbes commonly found inside caves in other countries, such as Ukraine and the United States. These microbes appear to be impossible to kill. Boston said they show how difficult life on Earth can be.

    Miss Parker taught physics in a New York school. Last month she explained to one of her classes about sound ,and she decided to test them to see how successful she had been in her explanation. She said to them, “Now I have a brother in Los Angeles. If I was calling him on the phone and at the same time you were 75 feet away, listening to me from across the street, which of you would hear what I said earlier, my brother or you and for what reason?”

    Tom at once answered, “Your brother. Because electricity travels faster than sound waves.”“That's every good,” Miss Parker answered; but then one of the girls raised her hand, and Miss Parker said.“Yes, Kate.”

    “I disagree,” Kate said.“Your brother would hear you earlier because when it's 11 o'clock here it's only 8 o'clock in Los Angeles.”

For your next out-of-this-world vacation, you now have the option of literally going out of this world—-but it'll cost you $ 40 million. Then again, can you really put a price tag on having the time of your life? According to a new report from Popular Mechanics, Russia is looking to build a luxury hotel in outer space. There you will wake up to a breathtaking blue planet—--the earth! The hotel is expected to be stationed on the International Space Station (ISS).

While space tourism itself isn't exactly a novel idea, the notion of building a hotel out there hasn't been raised before. Really, other companies are still focused on the transportation part of the puzzle—-after all, a trip to space is enough for most folks.

    According to Popular Mechanics, the hotel will include a luxury orbital suite with big windows, personal hygiene(卫生) facilities, exercise equipment, and yes, WiFi. Because if you can't share your experience on social media, did it really even happen?

    Of course, the reasons behind the hotel aren't just for fun and games. Apparently, space tourism might be able to help the Russians pay for another module to add to the International Space Station. Russian space contractor RKK Energia is currently building the first such module, which will give scientists a laboratory and power supply station from which to conduct tests.

    If any of this is going to happen, however, Russia is going to have to hurry. With the ISS expected to be out of use in 2028, there's little time to build the hotel and find wealthy tourists to actually buy a trip into outer space.

    So if you've recently come into a fortune and are interested in what could be the time of your life, ISS is calling your name.

    Staying up late is a potential battle between parents and kids. But the solution could be as simple as changing your meal time.

    Researchers at the University of Surrey, UK, found that delaying (延迟) meals could help change one of the internal (内部的) body clocks. Besides a “master” clock in the brain, there are clocks in other parts of the body. They are usually synchronized (同步的) according to factors including light.

    During the study, researchers tested 10 participants to study the effect of changing meal times on their body clocks. The participants were given three meals – breakfast, lunch and dinner. In the first stage, participants received breakfast 30 minutes after waking. Lunch and dinner followed, after 5-hour intervals (间隔). In the second stage, each meal was delayed by 5 hours. Right after each stage, blood and fat samples (样本) were collected.

    Results showed that later meal times greatly influenced blood sugar levels. A 5-hour delay in meal times caused a 5-hour delay in the internal blood sugar rhythms (规律性变化).

    The discovery showed that meal times are in line with (与……一致) the body clock that controls blood sugar levels.

    This is a small study but the researchers believed the findings could help jet lag (飞行时差反应) sufferers and night-shift (夜班的) workers.

    In a study by the University of Surrey in 2013, researchers explored what happened when a person's body was changed from a normal pattern to that of a night-shift worker's.

    After people work through the night, over 97 percent of the body's rhythmic genes are disrupted (扰乱).

    These findings explain why we feel so bad following a long flight, or after working at night, according to Simon Archer, one of the study's researchers.

    “It's like living in a house. There's a clock in every room in the house and in all of those rooms those clocks are now disrupted, which of course leads to chaos (混乱) in the household,” fellow researcher Derk-Jan Dijk told the BBC.

    Changing meal times didn't affect the “master” body clock – the one controlling when we get sleepy – but it can reset the body clock that controls blood sugar levels.

    This wouldn't necessarily cure jet lag completely, but it might reduce the negative effects.

    A study published earlier this year suggested that just a weekend camping trip could be enough to reset our body clocks. And now this latest research shows regular food schedules could play a key part too.