People have smoked cigarettes for a long time now. The tobacco which is used to make cigarettes was first grown in what is now part of the United States. Christopher Columbus, who discovered America, saw the Indians smoking. Soon the dried leaves were transported to Europe. In the late 1800s, the Turks made cigarettes popular.

    Cigarette smoke contains at least two harmful substances, tar and nicotine. Tar, which forms as the tobacco burns, damages the lungs and therefore affects breathing. Nicotine, which is found in the leaves, causes the heart to beat faster and increases the breathing rate. Nicotine in large can kill a person by stopping a person's breathing muscles. Smokers usually take in small amounts that the body can quickly break down.

    Nicotine can make new smokers feel dizzy(头晕) or sick to their stomachs. The heart rate for young smokers increases 2 to 3 beats per minute. Nicotine also lowers skin temperature and reduces blood flow in the legs and feet. It plays an important role in increasing smokers' risk of heart disease and stroke.

    Smoking cigarettes is dangerous. Cigarette smoking was the cause of lung cancer and several other deadly diseases.

    When I came to Cincinnati as an au pair (家庭打工留学生), a lot of things there were different from what I knew. My host family lived in a huge house I could only describe as a "castle"．In Germany I had lived in a small apartment together with my mom. Soon I found out that the "castle" was actually rather small in our neighborhood.

    Everybody there was very friendly and polite. They greeted you when they were walking by at least 3 feet away from you. They must not have seen a German au pair before, for most people I met asked me all kinds of questions about Germany. I enjoyed answering their various strange questions. I made a lot of friends and I started to hang out with them.

    Of course, there were a number of new things, and it took me the whole year to find them all out. I never got homesick. Perhaps it was because I did not have too many negative experiences and felt loved and welcomed there.

    However, I had undergone some painful experience back in Germany. I was frustrated by the way people would run me over and not even say "Sorry." Taking up my studies at the TU-Dresden, I felt lonely. Everybody here seemed to be withdrawn(离群的) and I missed everything I had in Cincinnati. Germany was so "cold". I found it so much harder to make new friends. After six months I got a roommate and only two good friends. I also flew back to Cincinnati several times for long periods. I felt that without those visits I was not able to make it.

    Now I am over this German culture shock. It almost took me an entire year. I am still going back and forward between Dresden and Cincinnati four times a year.

    Life in the Clear

    Transparent animals let light pass through their bodies the same way light passes through a window. These animals typically live between the surface of the ocean and a depth of about 3,300 feet—as far as most light can reach. Most of them are extremely delicate and can be damaged by a simple touch. Sonke Johnsen, a scientist in biology, says, “These animals live through their life alone. They never touch anything unless they're eating it, or unless something is eating them.”

    And they are as clear as glass. How does an animal become see-through? It's trickier than you might think.

    The objects around you are visible because they interact with light. Light typically travels in a straight line. But some materials slow and scatter(散射) light, bouncing it away from its original path. Others absorb light, stopping it dead in its tracks. Both scattering and absorption make an object look different from other objects around it, so you can see it easily.

But a transparent object doesn't absorb or scatter light, at least not very much, Light can pass through it without bending or stopping. That means a transparent object doesn't look very different from the surrounding air or water. You don't see it —-you see the things behind it.

    To become transparent, an animal needs to keep its body from absorbing or scattering light. Living materials can stop light because they contain pigments(色素) that absorb specific colors of light. But a transparent animal doesn't have pigments, so its tissues won't absorb light. According to Johnsen, avoiding absorption is actually easy. The real challenge is preventing light from scattering.

Animals are built of many different materials—-skin, fat, and more—-and light moves through each at a different speed. Every time light moves into a material with a new speed, it bends and scatters. Transparent animals use different tricks to fight scattering. Some animals are simply very small or extremely flat. Without much tissue to scatter light, it is easier to be see—through. Others build a large, clear mass of non-living jelly-lie(果冻状的)material and spread themselves over it .

    Larger transparent animals have the biggest challenge, because they have to make all the different tissues in their bodies slow down light exactly as much as water does. They need to look uniform. But how they're doing it is still unknown. One thing is clear for these larger animals, staying transparent is an active process. When they die, they turn a non-transparent milky white.

    Ownership used to be about as straightforward as writing a cheque. If you bought something, you owned it. If it broke, you fixed it. If you no longer wanted it, you sold it or threw it away. In the digital age, however, ownership has become more slippery. Since the coming of smartphones, consumers have been forced to accept that they do not control the software in their devices; they are only licensed to use it. As a digital chain is wrapped ever more tightly around more devices, such as cars and thermostats, who owns and who controls which objects is becoming a problem. Buyers should be aware that some of their most basic property rights are under threat.

    The trend is not always harmful. Manufacturers seeking to restrict what owners do with increasingly complex technology have good reasons to protect their copyright, ensure that their machines do not break down, support environmental standards and prevent hacking. Sometimes companies use their control over a product's software for the owners' benefit. When Hurricane Irma hit Florida this month, Tesla remotely updated the software controlling the batteries of some models to give owners more range to escape the storm.

    But the more digital strings are attached to goods, the more the balance of control leans towards producers and away from owners. That can be inconvenient. Picking a car is hard enough, but harder still if you have to dig up the instructions that tell you how use is limited and what data you must give. If the products are intentionally designed not to last long, it can also be expensive. Already, items from smartphones to washing machines have become extremely hard to fix, meaning that they are thrown away instead of being repaired.

    Privacy is also at risk. Users become terrified when iRobot, a robotic vacuum cleaner, not only cleans the floor but also creates a digital map of the inside of a home that can then be sold to advertisers (though the manufacturer says it has no intention of doing so). Cases like this should remind people how jealously they ought to protect their property rights and control who uses the data that is collected.

    Ownership is not about to go away, but its meaning is changing. This requires careful inspection. Devices, by and large, are sold on the basis that they enable people to do what they want. To the extent they are controlled by somebody else, that freedom is compromised.

    Alibaba opened China's version of Amazon's cashier-less store, “Tao Cafe” at its second annual Taobao Maker Festival taking place from 8—12 July, and then showed it to the public. By scanning a QR code（二维码）on Taobao app at the entrance of the store« consumers are tracked with cameras for facial recognition. After going through the checkout doors, customers will automatically make a purchase through their smartphones without needing to head to a register and be able to leave the store with what they buy in hand.

    The company, putting its efforts in Artificial Intelligence and data technologies, caused some ripples（波动）among offline retailers （零售商）. But if you think the e-commerce giant plans to get a slice of the physical-store pie, then you might get it wrong: “It's not about Alibaba wanting to open more cafes, we are not in the restaurant business.” it's about digitalizing the footprints of the visitors to an offline store, '' said Chris Tung, chief marketing officer of Alibaba Group.

    He said, for example, in the online world, Alibaba can always personalize every web page based on users interest and preference thanks to big data, “When you open our app, every moment is different.” But on the other hand, “offline is becoming not so exciting anymore”, because many physical stores are always found to be very similar with no variation.

    Tung said offline retailers could improve by adopting online data competence to link the identity of the customers» and optimize（优化）their in-store shopping experience. So in this sense, after physical stores have an understanding of what their customers need online, then they can allocate the products in the physical offline store accordingly. He further explained the pop-up Tao Cafe is one of the ways to present this “new retail” idea and opens up people's thinking and calls for more partnership.

If you've ever seen a sparrow steal your dog food or a crow open a garbage bag, you get a sense of that some birds have learned to take advantage of new feeding opportunities—a clear sign of their intelligence. Scientists have long wondered why certain species of birds are more innovative than others, and whether these capacities stem from larger brains or from a greater number of neurons（神经元） in specific areas of the brain.

It turns out that it's a bit of both, according to a recent study by an international team that included members from McGill University published in Nature Ecology and Evolution.

The researchers used a new technique to estimate the number of neurons in a specific part of the brain called the pallium in 111 bird species. The pallium in birds is equal to the human cerebral cortex（大脑皮层）, which is involved in memory, learning, reasoning, and problem-solving, among other things. When these estimates about neuron numbers in the pallium were combined with information about over 4,000 feeding innovations, the team found that the species with the higher numbers of neurons in the pallium were also likely to be the most innovative.

"The amount of time chicks spend in the nest as their brains develop might also play acrucial role in the evolution of intelligence," says McGill University Emeritus Professor Louis Lefebvre who spent more than 20 years gathering examples of feeding innovations. "Larger species of crows and parrots, which are known for their intelligence, spend longer in the nest, which allows more time for the brain to grow and accumulate pallial neurons."

The results of the study help to deal with previously opposed views of the evolution and significance of brain size and show how a life-history perspective helps to understand the evolution of cognition.