No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n'roll. Long-ago builders could have attached wooden pole s to the stones and rolled then across the sand, the scientists say.
“Technically, I think what they're proposing is possible,” physicist Daniel Bonn said.
People have long puzzled over how the Egyptians moved such huge rocks. And there's no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.
The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect workers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.
Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.

However, physicist Joseph West thinks there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , ‘Why don't they just try rolling the things?'“A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone” a lot easier to roll than a square”.
So he tried it.
He and his students tied some poles to each of four sides of a 30-kilogram stone block. That action turned the block into somewhat a wheel. Then they placed the block on the ground.
They wrapped one end of a rope around the block and pulled. The researchers found they could easily roll the block along different kinds of paths. They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.
West hasn't tested his idea on larger blocks, but he thinks rolling has clear advantages over sliding. At least, workers wouldn't have needed to carry cattle fat or water to smooth the paths.

    Next time you raise an eyebrow at the views of your partner, friend, sibling (兄弟姐妹) or colleague, remember they could be helping to make you smarter.

    New research shows that intelligence is not fixed but can be boosted throughout adulthood by family members, bright mates and intellectually stretching (拉伸) careers.

    The study challenges the commonly held belief that intelligence is static by the age of about 18. Current scientific consensus suggests that intelligence is controlled by genes, with environmental factors such as schooling and nutrition playing a partial role up to this age. After this point, IQ scores stabilize (稳定).

    But James Flynn, professor of political studies and psychology at the University of Otago in New Zealand, argues that people can “upgrade” their own intelligence throughout their lives. He believes intellectual stimulation (刺激) from others is crucial as the “brain seems to be rather like a muscle – the more you use it, the stronger it gets”. However, the opposite is also true – so people sharing a home or workplace with those who are intellectually challenged risk seeing their IQ levels fall as a result.

    He found the “understanding quality” of a family changes the IQs of all members, especially children. It can “lift” or hold back, depending on the “gap between their brightness and that of their siblings and parents”. A bright ten-year-old with brothers and sisters of average intelligence will suffer a five to ten point IQ disadvantage, compared to a similar child with equally bright siblings. However, children with a low IQ could gain six to eight points by having brighter siblings and special educational treatment to help pull them up.

    Professor Flynn also concluded that although genetics and early life experiences determine about 80 percent of intelligence, the remaining 20 percent is linked to lifestyle. This means that people can raise their IQ, or allow it to fall, by ten points or more. Therefore, the best way to boost IQ level is to mix with bright friends, find an intellectually challenging job and marry someone cleverer.

    Dodder is an unusual and unwanted plant that attacks other plants. Except for its flowers, the plant looks like spaghetti, a kind of noodles in the shape of long thin pieces that look like string when they are cooked. It's almost leafless, thread-like stems (茎) hang down on top of other plants that dodder needs to stay alive. Dodder does not produce its own food. Instead, it steals food from other plants. It feeds by sucking juices from the plant which is wrapped around, often making its host very weak or even killing it.

    Dodder can find other plants by their smell. When a young dodder plant starts growing, it follows the smell of plants it prefers, like tomato plants, potato plants, or other farm crops. Unlike most plants that usually grow in the direction of light or warmth, a dodder plant will grow in the direction of, for example, tomato smell—if a tomato happens to be growing nearby.

    However, a young dodder plant must find a host plant quickly. It no longer needs its root once it is attached to the host and wrapped around it. If it cannot catch a smell of a potential host within a few days, it will dry up and disappear—even if there is plenty of water around. Once it finds a host, the young dodder plant will attach itself to it and start growing faster. At that point the dodder plant will drop its root.

    Dodder is thus a difficult weed to manage and a real headache for farmers. When it does get out of hand, dodder can greatly reduce a farmer's harvest or even destroy crops completely. Before sowing their produce, especially farmers in warm parts of the world often check to make sure no unwanted dodder seeds have mixed with their crop seeds. This is a good way to stop dodder plants from making their way to a crop field secretly.

    Times are a little tough at our house right now. Neither of us makes a lot of money, but years of experience have taught us how to walk between the raindrops and make it from one month to the next with a fair amount of grace. I cook a lot at home, more when we're facing difficult times. When I know that I have to keep us fed on not much money, I fall back on my grandmother's recipes. She taught me to cook.

    When I was a kid, my twin brother and I spent long summer weeks and Christmas vacations with my mother's parents in the mountains of North Carolina. Rather than go hunting with my grandfather on mornings, I found myself more and more in the kitchen with my grandmother, watching her making a lemon cheese pie with her soft hands.

    My great-grandmother died when my grandmother was 11 years old. As the eldest daughter, she was expected to take on all of the housework while attending school. Throughout the Great Depression, she learned how to make a little food go a long way. Vegetables were cheap, so she cooked a lot of them, mostly only using small amounts of meat for seasoning. Roast beef was a twice-a-month luxury, but there was nothing she couldn't do with a chicken, every part of it. Nothing went to waste.

    Now I understand that her food was sacred (神圣的). I feel connected to my grandmother and to hundreds of years of family when I'm in my kitchen making country food. In the delicious smells is a long tale of victory over hard times, of conquering starvation of not just surviving, but finding joy and pleasure in every meal of every day.

From grandmother I learned to take real satisfaction in feeding people. My grandmother would beam with pleasure over a heavily laden table and say: "Do you know what this would cost at the restaurant?" I never knew what restaurant in particular she had in mind, but I knew that the question was totally not fair, because no restaurant anywhere can cook like a grandmother. But now, thanks to her guidance and years of practice, I can.

    Smith College Precollege Programs offer intellectually inspiring and unique opportunities to high school girls who wish to pursue their academic interests in the classroom and beyond. Annually, these programs offer over 225 young women the freedom to explore challenging subjects while living and studying with other motivated students from around the world.

    College Admission Workshop: This new one-week program is for rising high school juniors and seniors who are beginning to look at colleges. It helps you gain a competitive advantage when you are applying to colleges. You can know how to write a college-level essay, excel in a college admission interview and give an introductory speech.

    Summer Science and Engineering Program: Do you want to conduct college-level research? This program is a unique four-week residential program that will give you a taste of both college life and college-level science. You will attend small classes taught by top faculty (学院) members. The classes also have a current Smith College student working as an intern (实习生).

    Discovering Women's History: This program allows you to explore the lives and writings of notable women of the 19th and 20th centuries. You will read the private papers of Sylvia Plath, Gloria Steinem and Virginia Woolf. You will also examine poet Emily Dickinson's personal diaries and letters. You will learn archival (档案的) research skills.

    Field Studies for Sustainable (可持续的) Futures: This program is for students who want to explore their interest in environmental protection in a directed way. You will learn about sustainable living and environmental science. Much of the program is conducted in the field, and you will engage in a variety of activities including hiking, visiting local farms and learning about sustainable food and agriculture.

The teenage Snowboarder.

I was born in Denver, USA. and started snowboarding aged eight when my dad took me to a resort in the mountains. About two hours from Denver. The hill looked unbelievably steep and scary. So My dad had to do a lot of persuading to get me on a board. Because I was so young. I hadn't even thought of asking him if I could start snowboarding? But he was already into it and wanted me to love it, too—-He made it look so simple, and in the end I managed just fine.

After this experience, it wasn't long before I'd developed a love of sport and had improved my ability too. I started competing aged ten. Some people entered loads of competitions and ended up getting bored of snowboarding. But my love of taking part and winning got stronger as I got older, which always help me to push myself harder. I enjoyed not having a fixed plan and sometimes this went well, like when I became the first female ever to get a perfect 100 at a local competition. I wasn't sure I'd even attempted the jumps that got me the score until I actually set off. That achievement increased my trust in my own abilities.

During the summer I focused on training and my studies while there's no snow. Although I trained daily, it's nice not having to stick to quite a strict diet like I did in the winter. I also got to spend lots of time with my friends then. It's the best way of dealing with not being able to do what I loved so much and what I was really good at.

Now. I have to think carefully about my future. Snowboarding is such a huge part of my life now. But I also feel it's important to have something else I can do. just in case I don't succeed as a professional snowboarder or I get injured. I'm wondering whether becoming a doctor is a possibility. if my active life allows time for doing a college degree, it's impossible to imagine myself growing tired of the sport. But I can't go on snowboarding my whole life.