激光的特性、原理和用途
What do a DVD player, supermarket scanner, printer, fiber optic internet connection, and industrial metal cutter have in common? They […]
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钟表运转的奥秘
Tick Tock . Tick Tock . The sounds of clocks and timepieces surround me . I’m standing inside the Willard House & Clock Museum in North Grafton, Massachusetts .
地球的山系
Mountains form some of the most spectacular landscapes in the world. In the highest mountains, huge peaks with steep sides are separated by deep valleys, cut by ice or fast-flowing rivers. Mountainous areas make up around a quarter of the land surface and are found across all continents.
基因水平转移
Genetic engineering has produced some amazing species. One type of corn has a gene from bacteria. The corn is safe for people to eat, but the plant poisons caterpillars that try to attack it.There’s also a salmon that grows to market weight in less than half the usual time of three years. It’s an Atlantic salmon with genes from a Pacific chinook salmon.
关于衰老，动物教会了我们什么
Aging is a fact of life. Even if you avoid bad accidents, injuries, and infections, you won’t stay healthy forever. Your body will break down as you get older. You’ll get wrinkles and achy joints. Your vision and hearing will fade. Your chance of developing cancer, heart disease, and many other ailments will greatly increase. Aging “bedevils us all,” writes Steven N. Austad in his book, Methuselah’s Zoo. He defines aging as “the progressive deterioration over time of bodily functions and defenses along with increasing susceptibility to diseases.”
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基因编辑技术—合成生物学的基本工具
Inside a living cell, something remarkable is happening. A very tiny machine cuts the cell’s DNA. Next, the cell repairs the broken DNA, but the segment where the cut happened no longer works the same way. The tiny machine has edited the DNA—the code of life.
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为什么我们要关注经济学
Amanda was three years old and had no interest in learning to use the bathroom. Her father, Steven Levitt, decided to try something new. He told his daughter, “Amanda, every time you go pee pee in the potty, I’m going to give you M&Ms. Okay?” Amanda loved M&Ms. At first, the plan seemed to be working perfectly. Amanda started going to the bathroom to pee. Levitt was very pleased with himself. But just a few days later, things changed. A few minutes after Amanda went to the bathroom, she said she had to go again! Every few minutes, she wanted to try to pee – just so she could get her candy reward. This wasn’t what Levitt had in mind at all.
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一款软件是如何开发出来的
When you think of software development, you probably think first of a person writing code. In fact, for any important piece of software, there will be many people involved and only some are developers.
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污染水—弗林特河与公共健康危机的故事
In November 2014, LeeAnne Walters turned on the tap in her kitchen in the city of Flint, Michigan. Disgusting, brown water streamed out. Over the following weeks, its color ranged from “light yellow to nasty, dark-looking
cooking grease,” she recalls.
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