【推荐2】How to Stay Healthy and Active

It is important to remain healthy and active throughout life, especially as you age. Try making a few changes that you think you will be able to manage.     1     Then they will become part of your natural routine

Inspire yourself by understanding the many benefits of exercise. When you don’t feel like working out, it might help to focus on the reasons why you made the decision to get fit. Exercise not only controls weight, but helps fight disease, improves the immune system, and gives you more energy.     2    

Choose an activity you enjoy. Many people find that going to a gym several times a week is a convenient way to exercise, but there are many other ways to stay healthy and active.     3     You might also consider taking lessons for something you’d like to learn: dancing, surfing, or ice skating.

    4     Having an “exercise friend” will help you both to stay motivated, and will make your workout time more enjoyable. For a fun weekend activity, get some friends together to play basketball, softball, volleyball, or tennis.

Set realistic goals.     5     And meeting your goal milestones will give you a wonderful boost of confidence and a feeling of accomplishment; however, be sure to break your overall goals down into small, manageable steps, so you won’t become discouraged.

【推荐1】When antibiotics（抗生素）first became available, farmers used them freely. Now scientists know that the overuse of antibiotics can cultivate drug-resistant bacteria that are dangerous to human health. Among debates over what kinds of restrictions should be put in place, figuring out how antibiotic-resistant bacteria evolve and make their way to humans remains an area of intense interest.

Jo Handelsman is tracing one such pathway that, as she puts it, travels from "farm to table."Handelsman, a microbiologist who is now associate director for science at the White House Office of Science and Technology Policy, looked into dairy cows, which are often treated with antibiotics and produce manure（排泄物）that farmers use on their crops. In addition to nutrients, that fertilizer may harbor antibiotic-resistant bacteria—a problem because the bacteria can come into contact with plants that are finally shipped to supermarkets and sometimes eaten raw.

To find out how those antibiotic-resistant bacteria come to exist, Handelsman and her colleagues at Yale University added manure from a nearby Connecticut farm to raised beds of soil in 2013. In this case, the manure specifically came from cows that were not treated with antibiotics. The researchers unexpectedly found that there were more soil bacteria carrying antibiotic-resistant genes when they were grown with the manure than when they were grown with synthetic nitrogen-based fertilizer—even though the cows were drug-free.

Previous research has found that manure from pigs treated with antibiotics contains resistant bacteria, but the cow-pie results suggest there are more factors promoting resistance besides antibiotic use. Something about manure itself may encourage naturally resistant bacteria to increase.

The findings should not, however, give the impression that resistance is everywhere, notes Lance Price, a microbiologist at George Washington University（who was not involved in the study）. "We can control this. There's very clear evidence that when we turn off the antibiotic tap, we bring down drug-resistant bacteria," says Lance.

Next on the farm-to-table schedule, Handelsman will test whether radishes grown in soil treated with cow manure are capable of taking up resistant genes from bacteria through their vascular system（循环系统）. "They have veins（血管）just like us," she says. "We don't have any evidence yet that they're taking up the bacteria, but it's a really interesting possibility."

【推荐2】How many plastic carrier bags have you got in your house? I seem to have cupboards full of them and it feels like they’re taking over my home! The shopping bag is just one example of the milion things we use made from this useful material, plastic. But unfortunately, it’s not the easiest thing to recycle and this is causing an environmental problem.

Most of our everyday plastic items end up in landfill, left to rot away for many years. But some of it blows away, causing damage to the natural environment and harming wildlife. The problem is most serious in our oceans.

The study, published in the journal Proceedings of the National Academy of Sciences, described how remote islands act as a “sink” for the world’s rubbish. They become collecting points for fishing items and everyday things including toothbrushes, cigarette lighters and razors (剃须刀); things that we throw away. Dr Jennifer Lavers from the University of Tasmania says, “Almost every island in the world and almost every species in the ocean is now being shown to be impacted one way or another by our waste.”

This highlights the potentially deadly effect of our disposable culture. When we throw something away, it doesn’t just disappear, it goes somewhere and because of the long-lasting nature of plastic, it takes a lot time to decompose (分解) and stays there causing great damage to the ocean’s ecology.

Some other recent worldwide research estimates that 90% of all seabirds have swallowed plastic. And worse still, this plastic is broken down into tiny particles (颗粒) over a long period by the wind and the waves, then sea creatures at the bottom of the food chain ingest (咽下) them. These creatures are eaten by the fish that we eventually consume.

The solution to this problem would be to use less plastic. So next time you pick up a carrier bag, or buy a plastic bottle of water, spare a thought for the birds and animals on the remote islands. What do you do to help the environment?

【推荐3】Crayfish (龙虾) appear anxious after moulting (换壳)

When a crayfish moults, it becomes temporarily weak.     1     “They worry, they have a fright state that makes them avoid potentially dangerous areas. It’s kind of like anxiety,” says Pascal Fossat at the University of Bordeaux in France.

Fossat and his colleagues collected crayfish near Bordeaux and stored them in individual tanks that were similar to their natural habitat. When the crayfish began to moult, the researchers placed them in an area that had two dark sections and two lit sections, and recorded their behaviour.

Over the following two days, the crayfish showed a strong preference for hiding in the dark regions.     2     For comparison, when the crayfish weren’t moulting, they typically spent about 30 percent of their time in the light. “They’re very weak when they remove the old exoskeleton (壳), and the new one is totally soft until they eat the old one to get back the minerals that make the new exoskeleton stronger,” says Fossat.

The team also took crayfish that weren’t moulting and injected them with an ecdysteroid — a class of hormone that controls moulting. They found that the crayfish exhibited the same aiixiety-like behaviour.

To explore whether it was possible to change this behaviour, Fossat and his colleagues took the animals they had treated with the ecdysteroid and injected them with anti-anxiety drugs developed for use in humans.     3     “They didn’t have the fright from before,” says Fossat.

Fossat suspects crayfish may be capable of other emotions — although it is a difficult subject to investigate because crayfish are biologically so different from humans.

Robert Elwood at Queen’s University Belfast in the UK says he animals may be acting on basic physiological mechanisms that humans have interpreted as feelings. But he says that new research is helping us understand the range of emotions invertebrates (无脊椎动物) may experience.

“We’ve spent a lot of time worried about animal welfare, asking whether they are in stress or pain,” he says. “    4    ”

【推荐1】With a new year come new opportunities, and there’s no time like the present to start learning more about parts of the world you’ve never dreamed of before. Forget the standard bucket list: Machu Picchu, Mt Everest, Galapagos Islands—these places are over-visited. And besides, why follow the beaten path when you can get off it?

Lush green forests, amazing surf breaks, and village ruins greet visitors to El Salvador. Compared to the popular Costa Rica, the country’s coastline is a surf-enthusiast’s dream. If you’d rather be under the water than gliding along it, then grab the chance to dive in a live volcano. Lake Ilopango sits 460 meters above sea level, near the capital of San Salvador. Freshwater sponges, along with freshwater fish, lava flows along underwater cliffs and pillow lava deposits are just some of the incredible sites. Thanks to the hot vents in the lake bed the water is a balmy 85F.

Hike the multicolor peaks in Zhangye, Gansu Province, which is also home to hidden caves, rock formation, and temples balanced precariously on cliff faces. The otherworldly colors look just like a painted rainbow and give Peru’s much-visited mountains of the same name a run for their money.

Made up of 10 islands, two large and eight smaller ones, there are very few tourists who make it all the way to Samoa. Packed with natural wonders: ocean trenches, epic waterfalls, and stunning beaches, it’s a must do for outdoor enthusiasts. There’s ample hiking too, from World War II heritage trails to a “cloud rainforest” hike and a trek up to the peak of Mount Alava.

Technically an external territory of Australia, Christmas Island is dominated by around 50 million red crabs. Head to this remote island to witness the stunning spectacle of their annual migration, plus keep an eye out for manta rays, dolphins, and whale sharks that patrol the 80km of coastline. It’s not an easy place to get to, but the near-deserted beaches and friendly community make it worth the adventure.

【推荐2】The Australian Antarctic Division is ready to lead one of the most ambitious and challenging scientific projects yet undertaken in Antarctica-the quest to drill an ice core containing a million-year record of Earth’s climate and atmospheric history.

This record will help solve a long-standing mystery about the timing of past ice ages-why, almost one million years ago, the cycle of ice ages shifted from a regular 41,000-year cycle to an ice age every 100,000 years.

The Antarctic ice cap is formed by layers of snowfall, which are compressed at depth into ice. Trace chemicals and particles trapped in the ice layers provide data on how the climate and atmosphere has changed over time. Past temperature, the frequency and power of volcanic eruptions, sea ice coverage, dustiness and wind patterns are all recorded.

Air pockets in the snow become trapped as bubbles(气泡) in the ice. Each bubble is an original sample of the atmosphere, from the time the snow was transformed to ice. Carbon dioxide, methane, oxygen and other gases can be extracted from the bubbles to reveal their past atmospheric concentrations.

The 41,000-year ice age cycle matches a known periodicity in the tilt(倾斜) of Earth’s axis. The 100,000-year cycle matches a periodicity in the shape of the Earth’s orbit. Why the ice age cycles shifted from being paced by one parameter (参数) to the other is unresolved. The Antarctic ice sheet witnessed these changes and the answer to the puzzle may lie in the ancient ice.

A leading theory is that declining atmospheric CO2 levels were the cause of the longer, colder ice ages. The million-year ice core record will provide the essential CO2 record to test this theory. By greatly extending the detailed record of Earth’s climate history, the million-year ice core will also place current changes in climate and greenhouse gas concentrations into a deeper context.