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.

    Most damagingly, anger weakens a person's ability to think clearly and keep control over his behaviour. The angry person loses objectivity in evaluating the emotional significance of the person or situation that arouses his anger.

    Not everyone experiences anger in the same way; what angers one person may amuse another. The specific expression of anger also differs from person to person based on biological and cultural forces. In contemporary culture, physical expressions of anger are generally considered too socially harmful to be tolerated. We no longer regard duels(决斗) as an appropriate expression of anger resulting from one person's awareness of insulting behaviour on the part of another.

    Anger can be identified in the brain, where the electrical activity changes. Under most conditions EEG(脑电图) measures of electrical activity show balanced activity between the right and left prefrontal(额叶前部) areas. Behaviourally this corresponds to the general even­handed disposition(意向) that most of us possess most of the time. But when we are angry the EEG of the right and left prefrontal areas aren't balanced and, as a result of this, we're likely to react. And our behavioural response to anger is different from our response to other emotions, whether positive or negative.

    Most positive emotions are associated with approach behaviour: we move closer to people we like. Most negative emotions, in contrast, are associated with avoidance behaviour: we move away from people and things that we dislike or that make us anxious. But anger is an exception to this pattern. The angrier we are, the more likely we are to move towards the object of our anger. This corresponds to what psychologists refer to as offensiveanger: the angry person moves closer in order to influence and control the person or situation causing his anger. This approach­and­confront behaviour is accompanied by a leftward prefrontal asymmetry(不对称) of EEG activity. Interestingly, this asymmetry lessens if the angry person can experience empathy(同感) towards the individual who is bringing forth the angry response. In defensiveanger, in contrast, the EEG asymmetry is directed to the right and the angry person feels helpless in the face of the anger­inspiring situation.

Weekend Photography Workshop(研讨班): Seattle Aims

Learn new techniques from a great photographer

Take photos of Pike Place Market, Bainbridge Island, and more

Activity Details

    Seattle is a fantastic place to photograph. Spend the weekend taking photos of the historic Pike Place Market, get a new angle on the Space Needle, and photograph harbor views on Bainbridge Island.

    This workshop is led by a great photographer and a professional instructor and is designed for people who are interested in improving their digital photography. All participants must bring a digital SLR camera(单反相机), a laptop, and the software for organizing and presenting images. The workshop is limited to 25 participants.

Plan – 3 Days

Day 1—Thursday: Seattle

    Settle into our hotel or stay in accommodations of your choice. Gather tonight at a restaurant in town for a welcome dinner.

Day 2—Friday: Pike Place Market & Pioneer Square

    Start the day in the classroom with an instructive talk by our photographer. Our first task this afternoon takes us to the oldest running farmers' market in the country, Pike Place Market. Work on portraits, street scenes, and food photographing. Then photograph the stately 19^th century brick buildings of Pioneer Square, Seattle's historic center. End the day with an edit-and-critic meeting.

Day 3—Saturday: Olympic Sculpture Park & Space Needle

    Head out to the Olympic Sculpture Park. Then go to the streets of the downtown area to get a unique view of the Space Needle, and photograph city life against a background of diverse architectural styles. Tonight, we'll present our best images to the group, enjoy dinner at a local restaurant and end our journey.

Cost

    Meals noted in the plan are included in both options(with and without hotel)

Dates

Jul 11 – 14, 2013     Aug 08—11, 2013       Sep 26 – 29, 2013

Contact Information

    For questions about this workshop, please call 1-886-797-4686. Or you can visit the website: http://www. nationalgeographicexpeditions.com.

It's a popular belief that a fish's memory lasts for only seven seconds. It may seem sad to think that they don't remember what they've eaten or where they've been, and they don't recognize you or any of their friends—every moment in their life would be like seeing the world for the first time.

    But don't be so quick to feel sorry for them. A new study has found that fish have a much better memory than we used to think. In fact, certain species of fish can even remember events from as long as 12 days ago.

    In the study, researchers from MacEwan University in Canada trained a kind of fish called African cichlids to go to a certain area of their tank to get food. They then waited for 12 days before putting them back in the tank again.

Researchers used computer software to monitor the fish's movements. They found that after such a long break the fish still went to the same place where they first got food. This suggested that they could remember their past experiences.

    In fact, scientists had been thinking for a long time that African cichlids might have a good memory. An earlier study showed that they behaved aggressively in front of certain fish, perhaps because they remembered their past “fights”. But until the latest findings, there was no clear evidence.

    Just as a good memory can make our lives easier, it also plays an important part when a fish is trying to survive in the wild.

    “If fish are able to remember that a certain area contains safe food, they will be able to go back to that area without putting their lives at risks,” lead researcher Trevor Hamilton told Live Science.

    For a long time, fish were placed far below chimpanzees, dolphins and mice on the list of smart animals. But this study has given scientists a new understanding of their intelligence.

    Schools across the world are trying to come up with solutions to keep students active. Some are replacing traditional classroom chairs with exercise balls or standing desks. At Ward Elementary School in Winston, North Carolina students have adopted a new program that requires riding fixed bikes while reading.

    'Read and Ride' is the creation of school counselor Scott Ertl, who came up with the idea while he was exercising and reading at the gym. Believing it would be a fun way to convince students to become more active, he placed one in the corner of his classroom and encouraged them to use it during independent reading classes.

    It was so popular that Ertl decided to add more bikes and offer the Read and Ride program to the entire school. Today Ward Elementary has a dedicated exercise room filled with bikes that can be used by students while completing their daily reading assignments.

    Besides making reading more fun, the program also helps students exercise at a comfortable pace without the pressure that comes with regular sports-related activities. It is also a perfect way to release energy during days when the weather is not helpful to outdoor activities.

    Most importantly, however, are the program's academic benefits. A year after Read and Ride was introduced at Ward Elementary School, students actively involved in the program demonstrated an astonishing 83% reading proficiency. Those that had not taken advantage of the exercise bikes tested at a much lower, 41%.

    Though the substantial improvement in academic achievement cannot all be attributed to programs like Read and Ride, experts believe they are a significant contributor. That's because studies have shown that physical activity stimulates（刺激） brain cells and helps prepare it for learning. As word of the difference made by this easy to execute exercise program spreads, don't be surprised to find schools across the country adopt “Read and Ride” for their students.