If you're showering every day, you're probably over doing it. In fact, showering too often can actually hurt your body in the long run.

    As Time's public health column explains, daily showers are common due to social norms more than any proper health need. We connect being freshly showered with being attractive and pleasing, so we tend to showering often to feel better.

    But what's the ideal shower frequency? In terms of your health — not how you look or smell — probably once or twice a week, assistant professor of dermatology at George Washington University, Dr. C. Brandon Mitchell says. “Your body is naturally a well-oiled machine,” he says. “A daily shower isn't necessary.”

    Of course, your situation may vary. If you have a job like car maintenance or construction, you'll obviously have a visible layer of dirt you'll need to wash off every single day. Similarly, if you work out every day, you may not have any health risks by washing every day, but you'll still be smelly. If you feel like you need to take daily showers for aesthetic（审美的）reasons, at least make most of them light showers. “I tell patients who shower daily not to soap their whole bodies,” Mitchell says. Hit your pits, butt and groin, which are the areas that produce strong smells. The rest of your body doesn't need much soaping, he says.

    Too much time spent under the hot water can dry out your skin, cause cracks（裂纹）that can lead to infections or germs getting into your skin, and take away the natural oils on your skin that help keep it healthy. So, even if you're aiming to be your most presentable, be sure to keep it moderate to avoid hurting your skin in the long run.

    America is a mobile society. Friendships between Americans can be close and real, yet disappear soon if situations change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while - then no more. If the same two people meet again by chance, even years later, they pick up the friendship. This can be quite difficult for us Chinese to understand, because friendships between us flower more slowly but then may become lifelong feelings, extending (延伸) sometimes deeply into both families.

    Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. They will enjoy welcoming us and be pleased if we accept their hospitality (好客) easily.

    Another difficult point for us Chinese to understand Americans is that although they include us warmly in their personal everyday lives, they don't show their politeness to us if it requires a great deal of time. This is usually the opposite of the practice in our country where we may be generous with our time. Sometimes, we, as hosts, will appear at airports even in the middle of the night to meet n friend. We may take days off to net as guides to our foreign friends. The Americans, however, express their welcome usually at homos, but truly can not manage the lime to do n great deal with a visitor outside their daily routine. They will probably expect us to get ourselves from the airport to our own hotel by bus. And they expect that we will phone them from there. Once we arrive at their homes, the welcome will be full, worm and real. We will find ourselves treated hospitably.

    For the Americans, it is often considered more friendly lo invite a friend to their homes than to go to restaurants, except for purely business matters. So accept their hospitality at home!

Earth's geologic ages—time periods defined by evidence in rock layers—typically last more than three million years. We're barely 11,500 years into the current age, the Holocene. But a new paper argues that we've already entered a new one—the Anthropocene, or “new man”, age.

    The name isn't brand-new. Nobel Prize winner Paul Crutzen, a co-author of the paper, coined it in 2002 to reflect the changes since the industrial revolution. The paper, however, is part of new push to formalize the Anthropocene age.

    Recent human impacts have been so great that they'll result in an obvious boundary (界限 ) in Earth's rock layer, the author's say. “We are so skilled at using energy and exploiting the environment that we are now a defining force in the geological process on the surface of the Earth,” said co-author Jan Zala, a geologist with the University of Leicester in the UK. Even so, it could take years or even decades for the International Union of Geological Science to formalize the new age.

If the concept of the Anthropocene age is to be formalized, scientists will first have to identify and define a boundary line ,or marker, that's set in stone. “The key thing is thinking about how—thousands of years in the future—geologist might come back and actually recognize in the deposit in the UK.” It's not as straightforward as you might think. The market has to be very precise, and it has to be recognized in many different parts of the world,” said Haywood, who wasn't involved in the new study.

One candidate for the market is the distinctive radioactive signature left by atom bomb tests, which began in 1945. “The fallout (沉降 ) is basically across the world,” Haywood said. In a similar way, scientists used traces of the element iridium (铱) left by shooting star strikes to help define the boundary between the Cretaceous and Tertiary periods—the time of the great dinosaur extinctions.

    The push for a formal declaration of the Anthropocene age is about more than just scientific curiosity. The move the scientists write in the last issue of the journal Environmental Science & Technology, “might be used as encouragement to slow carbon emissions and biodiversity(生物多样性)loss” or “ as evidence on protection measures” Just as Haywood said, by underlining how much we're changing the environment, the formalization would be "a very powerful statement”.

New archaeological discovers suggest that trade between Europe and Asia along the Silk Road probably began in some form many centuries earlier than once thought. The findings, coupled with a widening range of scientific and historical research, could add a fascinating new page to the epic of the Silk Road.

The latest and most surprising discovery is pieces of silk found in the hair of an Egyptian mummy from about 1000 BC, long before regular traffic on the Silk Road and at least one thousand years before silk was previously thought to be used in Egypt. Other research may extend human activity along this route back even further, perhaps a million years to the migration of human ancestors into eastern Asia.

The official origin of East-West commerce along the road is usually placed in the late 2^nd century BC when an agent of the Chinese Emperor Wu-di returned from a dangerous secret mission across the western desert into the remote high country of Central Asia. The agent, Zhang Qian, travelled as far as Afghanistan and brought back knowledge of even more distant lands such as Persia, Syria and a place known as Lijien, perhaps Rome. Historians have called this one of the most important journeys in ancient times. His journey opened the way for what have been thought to be the first indirect contacts between the ancient world's two superpowers, China and Rome. Chinese silk, first traded to central Asian tribes for war horses and to the Parthians of old Persia in exchange for acrobats and ostrich eggs, was soon finding its way through a network of merchants to the luxury markets of Rome.

But the new discoveries show that Chinese silk was apparently present in the West long before the Han emperor started organized trade over the Silk Road. The research could change thinking about the early history of world trade and provide insights into the mystery of just how and when Europe and the Mediterranean lands first became aware of the glorious culture at the other end of Eurasia.

    A great number of species make their home in the vast waters of the Atlantic Ocean. Although the entire ocean makes up an ecosystem, many smaller habitats are found within, including an open-water habitat off the coast of the Northern Atlantic Ocean known as the Sargasso Sea. Sargassum is an alga(海藻) that floats in masses that can continue for miles. The waters of the Gulf Stream push the water in a northward move into this area. This constant move and varying temperature support the accumulation of the brown-colored seaweed.

    The Sargasso Sea is so enormous that one method of information collection has not been enough for scientists to obtain an accurate picture of what takes place within this ecosystem. Researchers have needed to employ several methods of sampling. Methods such as dragging nets over the surface of the water and videotaping beneath areas of sargassum have served scientists well. Information collected has shown that the Gulf Stream pushes brown algae from open water into the Sargasso Sea area, creating a diverse floating habitat in an area that would otherwise not support that wildlife.

    In the most recent study of the sargassum community off the shores of North Carolina, eighty-one fish species were documented as using the area as a microhabitat. This is an increase from previous studies. The types of fish found here are both commercially and environmentally important. The South Atlantic Fishery Management Council is working to regulate the harvesting of sargassum. The Council hopes to have the area classified as an Essential Fish Habitat. Which would afford it certain protections.

    Further research needs to be done before scientists understand how to best protect the Sargasso Sea as well as understand how it goes about supporting so many important types of wildlife.

I arrived in this beautiful Spanish island at the start of September, full of enthusiasm and eager to start work as an English teacher. I sorted all the necessary paperwork out and moved into a flat of my own within the first couple of days. Great! Or so I thought. At 4 am and at several intervals after that, I was rudely awoken by the cock that lives opposite me. Fantastic! I now have five extra alarms every morning.

In the following weeks, I also started to notice a trend. Things in my flat started to break at the rate of one object per day, like the hot water, bowls, cups, shower, doors or glass shelves. Yes, I was clumsy but things just fell apart. If it wasn't broken, it would either be dirty or missing. Using my washing basket for the first time was pretty disgusting. When I took out my clothes, they were swiftly followed by a hundred or so insects that were living in the bottom.

As for the general lack of equipment in the house, there was no oven, tin opener, sharp knives or potato peeler. It turned out making a burger wasn't the best idea. I had a small microwave and a grill. I thought the general understanding was never to put metal in a microwave but I went with it. Smoke soon started to appear. I was not quite sure if it was the burger or the grill but as soon as I opened the door, the electricity cut out. I spent the following 10 minutes in a dark, smoky room hunting for the power switch using the light from my mobile phone, which broke the week after and left me without a connection to the outer world.

Luckily, I'm now borrowing a phone and my luck has returned. No more things have broken (probably because there is nothing left to break). I've also realized that even if a flat looks pretty, it doesn't mean its contents work. I am also learning how to adapt to life with limited, broken utensils.