Humans have launched themselves into the outer space. They've landed on the moon. They've built habitable space stations that orbit the Earth. The next giant leap for mankind is to reach another planet – specifically, Mars.

    The problem is that it's no easy task. The planet is 586 times further away from the Earth than the moon, and it'll take around 180 to 220 days to reach Mars, depending on where each planet is in its orbit. Such long periods in space have suggested many potential health problems, including hormonal changes, skin conditions, and muscle and bone deterioration (损耗).

    Here's where some furry friends come in. A wide range of animals have been in space, from fruit flies and spiders to cats, and dogs. Such experiments began as far back as the late 1940s in first tests to see if living things could withstand the extreme g-force (重力) of a rocket launch.

    Mice continue to play a very important part in space experiments, mainly because the animals make excellent test subjects. They're small, which makes them inexpensive and easy to care for. In addition, their size and short life span make it possible to do the equivalent of several human years of tests in a much shorter time. Finally, because mice are mammals, they share many common characteristics with humans in terms of genetics, biology and behavior.

    Astromice have hit the headlines recently, as a team of scientists led by Betty Nusgens, professor of biology at the University of Liege in Belgium, found that the mice suffered a 15 percent thinning of their skin after 91 days aboard the International Space Station (ISS).

    This experiment was part of a wider NASA mission (任务) called the Mice Drawer System (MDS). The Italian Space Agency developed the facility, which allows six mice to be housed, monitored, and automatically fed and watered aboard the ISS, among which three survived during the mission.

    The mice have participated in 20 separate experiments, to study such effects as osteoporosis (骨质疏松症), anemia (贫血) and heart health.

    Results for the 20 experiments are coming in gradually. But it's clear that mice continue to play an important role in the ongoing quest to conquer the final frontier.

    Most visitors come to the UK expecting the rain and weather for which the country is famous. However, when summer finally arrives, British people like nothing more than heading for the coast. Here are some of more famous places of interest that you could expect to visit on a trip to Britain. Black pool, in the northwest of England, is the most visited place in the UK. Each year around 6.5 to 7 million people come to enjoy the miles of sandy beaches, the 158m Black pool Tower and the 11km-long Golden Mile, where there are entertainments, pubs, ice rinks (溜冰场) and even a zoo. On the south coast of the country you can find Brighton. Until 1786, Brighton was a sleepy village. Then the future king, George IV, decided to build a house there, and now it has become a large, international centre. Apart from the beaches, Brighton is famous for its pier (码头). There are theatres, entertainments and restaurants there. Brighton is also fantastic for shopping. If you want to travel a little further, why not go to Cornwall in the far southwest of the UK? South Cornwall offers miles of sandy beaches and beautiful scenery. The climate there is warmer than the rest of Britain, and you can even find palm trees. For a bit more excitement, go to North Cornwall. The scenery there is nicer, and the beaches are famous for their powerful waves. As a result, North Cornwall has become the home of British surfing. One word of warning though, if you are using the roads in the UK during holidays, you can expect long traffic jams on the motorways. It might be better to take the train.

    Abraham Lincoln, a self-taught lawyer, was elected 16th president of the United States in November 1860, shortly before the outbreak of the Civil War. Lincoln proved to be a smart military strategist and a competent leader: His Emancipation Proclamation(解放宣言) paved the way for slavery's abolition, while his Gettysburg Address stands as one of the most famous speeches in American history. In April 1865, with the Union on the brink of victory, Abraham Lincoln was killed; his untimely death made him a hero to the cause of liberty, and he is widely regarded as one of the greatest presidents in U.S. history.

    On January 20, 1981, Reagan took office. Only 69 days later he was shot by a would-be killer, but quickly recovered and returned to duty. His grace and wit during the dangerous incident caused his popularity to soar.

    At the end of his two terms in office, Ronald Reagan viewed with satisfaction the achievements of his innovative program known as the Reagan Revolution, which aimed to motivate the American people and reduce their reliance upon Government. He felt he had fulfilled his campaign pledge of 1980 to restore “the great, confident roar of American progress and growth and optimism.”

    When George W. Bush, at the age of 54, became the 43rd president of the United States, it was only the second time in American history that a president's son went on to the White House. John Quincy Adams, elected the sixth president in 1824, was the son of John Adams, the second president. While John Adams had brought up his son to be president, George Bush, the 41st president, insisted he was surprised when the eldest of his six children became interested in politics, became governor of Texas, and then went on to the White House.

    Barack Obama served as the 44th President of the United States. His story is the American story — values from the heartland, a middle-class upbringing in a strong family, hard work and education as the means of getting ahead, and the belief that a life so blessed should be lived in service to others.

    With a father from Kenya and a mother from Kansas, President Obama was born in Hawaii on August 4, 1961. He was raised with help from his grandfather, who served in Patton's army, and his grandmother, who worked her way up from the secretarial pool to middle management at a bank.

    Languages have been coming and going for thousands of years, but in recent times there has been less coming and a lot more going. When the world was still populated by hunter-gatherers, small, tightly knit(联系) groups developed their own patterns of speech, independent of each other. Some language experts believe that 10,000 years ago, when the world had just five to ten million people, they spoke perhaps 12,000 languages between them.

    Soon afterwards, many of those people started settling down to become farmers, and their languages too became more settled and fewer in number. In recent centuries, trade, industrialization, the development of the nation-state and the spread of universal compulsory education, especially globalization and better communications in the past few decades, all have caused many languages to disappear, and dominant languages such as English, Spanish and Chinese are increasingly taking over.

    At present, the world has about 6,800 languages. The distribution of these languages is hugely uneven. The general rule is that mild zones have fewer languages spoken by many people while hot, wet zones have more, often spoken by small numbers. Europe has only around 200 Languages: the Americas about 1,000, Africa 2,400; and Asia and the Pacific perhaps 3,200, of which New Guinea alone accounts for well over 800. The median number(中位数) of speakers is a mere 6,000, which means that half the world's languages are spoken by fewer people than that.

    Now over 400 of the total of 6,800 languages are close to extinction(消亡), with only a few elderly speakers left. None of these seems to have chances of survival.

    Courses & Curriculum of the College of Arts & Sciences in Cornell

If you are a psychology enthusiast, you have probably heard of the famous marshmallow test （棉花糖实验）. In this task, kids are given a marshmallow, and are told that they can eat that marshmallow now, or wait a little while, and have two marshmallows instead. Some kids eat the marshmallow immediately, but most try their best to wait for two. 

When the researchers followed up with those kids later in life, children who waited longer had better life outcomes: more academic success, better social behavior, and even markers of better health. They believe those children who keep waiting are the ones with the most self-control-a key factor in success, and that's why they are so successful later. 

But what if the behavior in the marshmallow test has more to do with cultural norms than self-control?

A 2022 study tested the idea that children may decide how long to wait for rewards based on what they are accustomed to waiting for in their culture. For example, in the United States, there is no widespread mealtime custom of waiting until everyone is served. In Japan, however, there is. 

Because of this difference in norms, the researchers hypothesized that Japanese children would wait longer in the marshmallow test than the American children. This is exactly what they found later in experiments. 

But this isn't conclusive evidence; after all, maybe Japanese children actually have better self-control, or maybe they differ from American children in other ways that could explain the result. 

In the U. S. , gifts are usually given on special occasions and children usually have to wait before they can unwrap their presents. In Japan, however, gift-giving happens more often, and children usually open presents immediately. 

Given these cultural differences, scientists expected that if they ran the test with gifts instead of marshmallows, American kids would wait longer. Once again, their hypothesis was correct. 

This is a powerful result because it demonstrates the importance of culture and habit in shaping behavior. If a child waits only few minutes before giving up on two marshmallows but much longer to unwrap a gift, can we really say that child lacks self-control? I don't think so. I think it just means that they are adjusting well to their social settings.