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.

    While high school does not generally encourage students to explore new aspects of life, college sets the stage for that exploration. I myself went through this 1 process and found something that has changed my 2 at college for the better: I discovered ASL—American Sign Language(美式手语).

    I never felt an urge to 3 any sign language before. My entire family is hearing, and so are all my friends. The 4 languages were enough in all my interactions(交往). Little did I know that I would discover my 5 for ASL.

    The 6 began during my first week at college. I watched as the ASL Club 7 their translation of a song. Both the hand movements and the very 8 of communicating without speaking 9 me. What I saw was completely unlike anything I had experienced in the 10. This newness just left me 11 more.  

    After that, feeling the need to 12 further, I decided to drop in on one of ASL club's meetings. I only learned how to 13 the alphabet that day. Yet instead of being discouraged by my 14 progress, I was excited. I then made it a point to 15 those meetings and learn all I could.

    The following term, I 16 an ASL class. The professor was deaf and any talking was 17. I soon realised that the silence was not unpleasant. 18, if there had been any talking, it would have 19 us to learn less. Now, I appreciate the silence and the 20 way of communication it opens.  

    Exercise may help to safeguard the mind against depression through previously unknown effects on working muscles, according to a new study involving mice.

    Mental health experts have long been aware that even mild, repeated stress can contribute to the development of depression and other mood disorders in animals and people. Scientists have also known that exercise seems to cushion against depression. But precisely how exercise, a physical activity can lessen someone's risk for depression, a mood state, has been mysterious. So for the new study, researchers at the Karolinska Institute in Stockholm studied the brains and behavior of mice in a complicated and novel fashion.

    We can't ask mice if they are feeling cheerful or in low spirits. Instead, researchers have pictured certain behaviors that indicate depression in mice. If animals lose weight, stop seeking out a sugar solution when it's available — because, probably, they no longer experience normal pleasures — or give up trying to escape from the cold-water zone just freeze in place, they are categorized as depressed. And in the new experiment, after five weeks of frequent but low-level stress, such as being lightly shocked, mice displayed exactly those behaviors. They became depressed.

    The scientists could then have tested whether exercise blunts (延缓) the risk of developing depression after stress by having mice run first. But, frankly, from earlier research, they wanted to know how, so they bred pre-exercised mice. A wealth of earlier research by these scientists and others had shown that aerobic exercise, in both mice and people, increases the production within muscles of an enzyme (酶) called PGC-1alpha. The Karolinska scientists suspected that this enzyme somehow creates conditions within the body that protect the brain against depression. Then, the scientists exposed the animals, which without exercising, were in high levels of PGC-1alpha to five weeks of mild stress. The mice responded with slight symptoms of worry. But they did not develop depression. They continued to seek out sugar and fought to get out of the cold-water zone. Their high levels of PGC-1alpha appeared to make them depression-resistant. Finally, to ensure that these findings are relevant to people, the researchers had a group of adult volunteers complete three weeks of frequent endurance training, consisting of 40 to 50 minutes of moderate cycling or jogging. The scientists conducted muscle biopsies (活体检查) before and after the program and found that by the end of the three weeks, the volunteers' muscle cells contained substantially more PGC-1alpha than at the study's start. The finding of these results, in the simplest terms, is that “you reduce the risk of getting depression when you exercise,” said Maria Lindskog, a researcher at the Karolinska Institute.

    It is necessary to be reasonable and flexible enough to avoid conflicts as much as possible and live in peace with others. If you have done all your best to avoid conflicts and you are still arguing, then read these effective tips on how to avoid conflicts.

● Don't get in the center of the conflict.

    Sometimes people can get in the center of conflicts due to their enthusiasm for offering help. Frankly speaking, it is very unwise, because it can make you the main figure of the conflict. You should focus on your own life issues.

● Be kind.

    Life is full of conflicts and disagreements, that's why you should find more conservative ways of dealing with them. For example, kindness can lessen the conflict.

● Try to be a peacekeeper.

    Peacekeepers tend to cooperate with people without bad emotions which usually lead to arguments and even conflicts. “” This saying is the life motto of a natural-born peacekeeper. Don't worry if you are not a natural-born peacekeeper; you can gain this skill during life.

● Walk off.

    When the conflict is gathering pace and you can't manage to control yourself, you should choose to handle the situation in another way. By all means, try to keep yourself away from stress. You should get away from the situation for a while.

“Write All About It”

Centerville High School Essay Contest

Rules

1). Students are asked to hand in essays of 500 to 700 words of their own work. Any essay containing material copied from another source will be disqualified.

2). Manuscripts should be typed double-spaced, with the student's name, address, and grade level on a separate sheet of paper.

3). Essays must be turned in by 4:00 P.M. on November 30. They can be brought to Mrs. Elton in Room 104 or to Mr. Markham in the school library.

Essay-Writing Tips

1). Catch your reader's interest—Your opening should immediately pull your reader into your essay. Asking a question or starting with a story, or surprising statement are some good ways to do this.

2). Create a picture—Use active words that show your reader what is happening. Instead of telling your reader that “the room was disordered,” paint a picture using active verbs and lively adjectives.

3). Have a purpose—Well-written essays do more than just describe an event or express a viewpoint; they also communicate a message.

4). Check for mistakes—Read your paper over to check for mistakes. Ask another student to read your paper. Another pair of eyes will often spot a mistake you have missed.

5). Format your essay—Neatly type your essay on white paper. Choose an attractive cover for handing in. The computer lab will be open after school from 3:15 to 4:45 P.M. each day this month so that students can use the computers.

Prizes

Winning essays will be published in the Centerville Times. Everyone who takes part in it will also receive a free pass to enter one school activity this year.

First Prize: $50 savings bond

Second Prize: Dictionary and reference book

Third Prize: Pen set and journal

Special thanks to the Centerville Writers' Association for the prizes to help encourage our aspiring authors. Good luck to all contestants.

    A warm drink of milk before bed has long been the best choice for those wanting a good night's sleep. But now a study has found it really does help people nod off—if it is milked from a cow at night.

    Researchers have discovered that “night milk” contains more melatonin(褪黑激素), which has been proven to help people feel sleepy and reduce anxiety.

    The study, by researchers from Seoul, South Korea, involved mice being fed with dried milk powder made from cows milked both during the day and at night.

    Those given night milk, which contained 10 times the amount of melatonin, were less active and less anxious than those fed with the milk collected during daytime, according to the study published in The Journal of Medicinal Food.

    Night milk quickened the start of sleep and caused the mice to sleep longer.

    While the effect of cows milk harvested at different times has not been tested on humans up to now, taking melatonin drugs has been suggested to those who are struggling to fall asleep at night.

    Previous studies have also indicated that milk can be excellent for helping sleep because of the calcium content, which helps people to relax.

    Milk is also sugar-free and additive-free with nutritionists recommending skimmed milk as the best choice before bed as it is the least fattening. The more fat you take in before bedtime, the greater burden you will put on your body at night.