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.

    Ecotourism(生态旅游): A Different Way to Travel

    Are you attracted to obscure(偏远的)places? Do you prefer to vacation away from other tourists? Are you careful to take only memories and to leave only footprints? If you answered yes to more than one of these questions, you just might be an ecotourist.

    Ecotourists are people who want to experience the unspoiled natural world and leave it that way when they return home. This trend started in the 1990s and ecotourism is now growing three times faster than the tourism industry at large. The Ecuador's remote Amazon Basin(盆地) is contributing to that expansion, and it gives a snapshot of what ecotourism looks like.

    At the Ecolodge, a small group of cabins(小屋) sits Kapawi Ecolodge in the middle of the Achuar people's reserve(保护区) and is only reached by air. From here, visitors can explore parts of the Amazon rainforest seen by few outsiders. As they do local Achuar guides explain how the forest is like their supermarket, where they find food, clothing, medicine and tools. As a result, tourists learn to appreciate the local culture as well as the natural environment.

    The owners of Kapawi pay monthly rent to the Achuar people, but they also train the community to run and manage the lodge. They have agreed on a plan to turn the operation over to the Achuar completely by 2011.The owners are working to make ecotourism benefit and empower the local people.

    You probably won't start your own ecolodge, but you can be an ecotourist if you follow these guidelines: Protect the environment; Support local businesses; Respect the local customs and traditions.

    The world is full of fascinating places to visit. As an ecotourist, you can enjoy them yourself and make sure that they remain beautiful for future generations as well.

    The town of Green Bank, West Virginia, is the site of the largest radio telescope in the world, so Internet connections and anything else that can create electromagnetic(电磁的) waves, such as smart phones and microwave ovens, are banned.

    Green Bank is frozen in time, somewhere in the 1950s, because there's a 33,000-square-kilometer zone of silence due to the telescope. Cell phone towers are forbidden.

    The closer you get to the telescope, the greater the restrictions. There's a 16-kilometer radius(半径) around the observatory where radio-controlled items, even toys, cannot be used.

    Telescope employees even work in a special room that blocks electromagnetic waves from leaving it. “Here imagine a submarine(潜艇), water cannot get inside, and so this room is an electric submarine. No electromagnetic waves can get into this room, just as you can't go beyond it,” Michael Holstein, an observatory officer, said.

    The size of a football field, the telescope is so sensitive that it could pick up signals sent from an alien world. And scientists can't wait for that to happen.

    “All the signals that we now receive with the help of telescopes are signals that come from cosmic objects — stars, galaxies. We have not yet received anything from intelligent civilizations,” scientist Richard Lynch said.

    Local people respect the work of the scientists. “Yes, we are different. Many would say that we live the old-fashioned way, in the past. But for us, it's just the way of life that we have always lived,” Sherry said.

    “When we want to meet friends, we just call each other on a wire phone. And instead of sitting in front of your screen, we talk, we go fishing, to the mountains,” resident Sherry said.

    For the latest news, residents read the weekly local newspaper. When she's looking for a phone number, Sherry reaches for the phone book.

    And instead of Facebook, Sherry enjoys daily conversations with her customers. In this town, everyone knows each other and communication is face to face.

    Professional development courses in London

    Business writing

    Delivery method: Online, Video

    Price: £49

    About the course: Many people get blocked when forced to put their thoughts into words at work. This course gives you the tools and techniques to improve your writing, whether it's a two-line email or a two-hundred-page report.

    Travel writing courses

    Delivery method: Classroom, Seminar

    Price: £115 (full day); £125 (evening classes)

    About the course: Do you want to be a travel writer? Then come along to a one-day travel writing workshop or a four-week travel writing evening class. The courses help participants to write travel features and publish them in newspapers, magazines or on websites.

    Pre-sessional programmes in EAP

    Delivery method: Classroom, Seminar

    Price: Starting from £1,250

    About the course: Our five pre-sessional programmes in English for academic purposes are intended for international students who plan to study at Aston University. These programmes aim to equip you with the language and academic skills necessary for success in your future chosen subject area.

    Masterclass

    Delivery method: Classroom, Seminar

    Price: Starting from £335

    About the course: Whether you write fundraising letters, or for your website(s), this course will help you gain the ideas, knowledge and skills you need to write fundraising copy that produces more impressive and profitable results.

    Some colors people see late at night could cause signs of clinical (临床的) depression. That was the finding of a study that builds on earlier study findings. They show that individuals who live or work in low levels of light overnight can develop clinical depression. Doctors use the word "clinical depression" to describe severe form of depression. Signs may include loss of interest or pleasure in most activities, low energy levels and thoughts of death or suicide.

    In the new study American investigators designed an experiment that exposed hamsters (仓鼠) to different colors. The researchers chose hamsters because they are nocturnal which means they sleep during the day and are active at night.

    The animals were divided into four groups. One group of hamsters was kept in the dark during their night-time period. Another group was placed in front of a blue light a third group slept in front of a white light while a fourth was put in front of a red light.

    After four weeks the researchers noted how much sugary water the hamsters drank. They found that the most depressed animals drank the least amount of water.

    Randy Nelson heads the Department of Neuroscience at Ohio State University. He says animals that slept in blue and white light appeared to be the most depressed. "What we saw is that these animals didn't show any sleep uneasiness at all but they did mess up biological clock genes and they did show depressive sign while if they were in the dim (微弱) red light they did not."

    He notes that photosensitive (感光) cells in the eyes have little to do with eyesight. He says these cells send signals to the area of the brain that controls what has been called the natural sleep-wake cycle.

    He says there's a lot of blue in white light. This explains why the blue light and white light hamsters appear to be more depressed than the hamsters seeing red light or darkness.

    British Museum Visitor Regulations

    Opening hours

    We open the Museum's galleries daily from 10：00 am until 17：30 pm. We keep selected galleries open until 20：30 pm on Fridays.

    The Museum's Great Court is open from 9:00 am until 18:00 pm; except on Fridays when it remains open until 20:30 pm.

    You may be asked by your staff to begin leaving up to ten minutes before closing time.

    The Museum is closed 24-26 December and 1 January.

    Admission

    We warmly welcome you on your visit to the Museum. In the interests of the security of all of our visitors we require you follow these regulations.

    Admission to the Museum is free, but we may charge for entry to some temporary exhibitions and events.

    Food and drink

    You aren't allowed to consume food and drink inside the Museum, except in places such as the restaurant and cafes or the forecourt. Families with children may use the Ford Centre for young visitors in the basement of the Museum's Great Court at weekends and during school holidays.

    Animals

    If you have a disability, you may be accompanied in the Museum by your guide, assistant or companion animal. You aren't allowed to bring animals into the Museum under any other circumstance.

    Film, photography and audio recording

    Except the place that are indicated by notices, you're permitted to use hand-held cameras (including mobile phones) with flash bulbs or flash units, and audio and film recording equipment not requiring a stand. You may use your photographs, film and audio recordings only for your own private and non-commercial purposes.