Elephants might be the most well-known and well-loved animal in African wildlife. But conservation (保护) of the African elephant faces special difficulties. While the elephant population is half of what it was 40 years ago, some areas of Africa have more elephants than populated areas can support. That's why AWF scientists are studying elephant behavior, protecting habitats and finding ways for humans to live peacefully with elephants in Africa.

    Years ago, over hunting and the ivory trade were the biggest threats to elephants survival. Luckily, ivory bans (禁令), hunting rules and protected areas protect elephants from these dangers today.

    The 21st century brings a different challenge to elephant conservation —land-use. Elephants walk across borders and outside parks and other protected areas. So they often destroy crops, causing conflicts (冲突) between local farmers and these big animals.

    Successful conservation strategies (策略) must allow elephants to walk freely in their natural habitats while reducing conflicts between elephants and local people.

    AWF researchers are searching for a way to give both elephants and people the space they need. The AWF is collecting information on elephant habitats and behavior. The information they gather will help to develop the widest possible space for elephants.

    The AWF is helping elephants by protecting their habitats. And they also work with local farmers to improve their life in order to encourage them to protect rather than destroy elephants.

    There was good news last week for people who struggle to get eight hours of sleep a night: they may not need so much shut-eye after all.

    Researchers from UCLA and elsewhere looked at sleep habits of remote hunter-gatherers in Tanzania, Namibia and Bolivia — groups with pre-industrial lifestyles whose sleep patterns are believed to reflect those of ancient humans. The researchers found that, on average, members of each group sleep a bit less than six and a half hours a night.

    The study, published in the academic journal Current Biology, indicates that “natural” sleep is less than eight hours a night and that modern society's numerous electronic distractions (分心) aren't necessarily to blame for people getting just six or seven hours of sleep.

    “The story that often gets out is that if you sleep for less than seven hours, you're going to die early,” he told me. “That's not true.”

    Yet Americans are addicted to getting more sleep — and on turning to medical shortcuts to help them.

    According to the Centers for Disease Control, as many as 70 million U.S. adults suffer from sleep disorders or sleeplessness. Only a third of Americans get the government's recommended seven to nine hours of sleep a night.

    About 9 million American adults use sleeping pills to help get a good night's rest, the CDC found. Siegel said the number of people relying on medicines “has gone up rather rapidly since then.”

    Industry consulting firm Global Data estimates that worldwide sales for sleeplessness medicines will run about $1.4 billion next year and reach $1.8 billion by 2023, recovering from lower sales in recent years because of cheaper generics(仿制药) hitting the market.

    Dr. Roy Artal, a sleep specialist in West Los Angeles, said it's understandable that busy people in today's go-go world would turn to medicines to speed up the sleep process. But all they're doing is building a reliance on powerful drugs for relatively little improvement.

    “There's no magic pill that makes us sleep when we want and wake up when we want,” Artal said. “The effects of sleeping pills tend to be modest.”

    He and other experts say the answer to sleeplessness isn't to be found in a pill bottle. It's in what's called “sleep hygiene (保健).”

A

Washington, D.C. Bicycle Tours

Cherry Blossom Bike Tour in Washington, D.C

    Duration: 3 hours

    This small group bike tour is a fantastic way to see the world-famous cherry trees with beautiful flowers of Washington, D.C. Your guide will provide a history lesson about the trees and the famous monuments where they blossom. Reserve your spot before availability - and the cherry blossoms - disappear!

Washington Capital Monuments Bicycle Tour

    Duration: 3 hours (4 miles)

    Join a guided bike tour and view some of the most popular monuments in Washington, D.C. Explore the monuments and memorials on the National Mall as your guide shares unique

facts and history at each stop. Guided tour includes bike, helmet, cookies and bottled water.

Capital City Bike Tour in Washington, D.C.

    Duration: 3 hour

    Morning or Afternoon this bike tour is the perfect tour for D.C. newcomers and locals looking to experience Washington, D.C.in a healthy way with minimum effort. Knowledge guides will entertain you with the most interesting stories about Presidents. Congress, memories, and parks. Comfortable bikes and a smooth tour route（路线） make cycling between the sites fun and relaxing.

Washington Capital Sites at Night Bicycle Tour

    Duration: 3 hour (7 miles)

    Join a small group hike tour for an evening of exploration in the heart of Washington, D.C. Get up close to the monuments and memorials as you bike the sites of Capitol Hill and the National Mall. Frequent stops are made for photo taking as your guide offers unique facts and history. Tour includes bike, helmet, and bottled water. All rides are equipped with reflective vests and safety lights.

    You probably know who Hillary Diane Rodham Clinton is, but you may not have heard of Margaret Munnerlyn Mitchell if you are not interested in foreign literature. Of the outstanding ladies listed below, who is your favorite?

    Jane Austen (16 December, 1775-18 July, 1817)

    Jane Austen, a famous English writer, was born at Steventon, Hampshire. She began writing early in life, although the prejudices (偏见) of her times forced her to have her books published anonymously (匿名).

    She wrote many books of romantic fiction about the gentry (贵族). Her works made her one of the great masters of the English novel. Only four of her novels were printed while she was alive. They were Sense and Sensibility (1811), Pride and Prejudice (1813), Mansfield Park (1814) and (1816).

    Charlotte Bronte (21 April, 1816-31 March, 1855)

    She first published her works, including Jane Eyre, under the false name of Currer Bell. Her first novel, The Professor, was rejected by many publishers. It was not printed until 1857. She is famous for her novel Jane Eyre (1847), which was very popular when it was printed. Jane Eyre was a strong story of a plain, brave, clever woman struggling with her passions, reasons, and social condition.

    Margaret Munnerlyn Mitchell (8 November, 1900-16 August, 1949)

    She was an American author and journalist, a lifelong resident and native of Atlanta, Georgia. One novel by Mitchell was published during her lifetime, the American Civil-War-Era novel, Gone with the wind, for which she won the National Book Award for Most Distinguished Novel of 1936 and the Pulitzer Prize for Fiction in 1937. In more recent years, a collection of Mitchell's girlhood writings and a novel she wrote as a teenager, Lost Laysen, have been published. A collection of articles written by Mitchell for The Atlanta Journal was republished in book form.

    The koala is an unusual creature. Native to Australia and a bit bigger than a rabbit, it spends most of its time in eucalyptus trees（桉树）, feeding on leaves that are poisonous to nearly every other animal on the planet.

    The koala sleeps about 22 hours a day and spends the remainder of its time eating and resting. It might spend 10 minutes a day moving, experts say, usually from one tree to another. It has a soft pad at the end of its spine and extra thick fur on its rear end to make the effort, of sitting more comfortable.

    Threats and protective measures

    The unique lifestyle of the koala has helped it prosper, but today the cute and iconic creature is facing threats from habitat loss, disease and a changing climate. Koala populations are expected to decline by 50 percent in the next 20 years according to the Australian Museum.

    To help protect these animals, which bring in an estimated $1.1 billion to Australia each year through koala-related tourism, an international team of researchers has published the first complete genome（基因组）of the koala. Their hope is that the keys to the marsupial's（有袋动物）long-term survival might be planted in its genetic code.

"The ultimate goal is that we won't have to…rescue them from the edge of extinction," said Rebecca Johnson of the Australian Museum Research Institute in Sydney, who led the work.

    "Now we have a really good understanding of the koala genome, and we are in a fantastic position to use that knowledge to help us manage them."

    Early findings

    An elementary analysis of the koala's genome, published in Nature Genetics, has already yielded some interesting findings.

    For example, the authors found that, compared to other mammals, the koala's DNA includes an expansion in the number of genes that encode for enzymes involved in anti-poison. That allows them to have a diet that depends almost entirely on eucalyplus leaves which are unusually high in poison. However, it also means that koalas metabolize（代谢）medicines like anti-chlamydia antibiotics faster than other animals.

    The koala genome also revealed why koalas are such famously picky eaters. They are known to consume leaves from just 20 of Australia's 60 known eucalyplus species. And even when they are in one of their preferred trees, koalas take leaf selection very seriously.

    Information waiting to be discovered

    Johnson said that the information encoded in the koala's DNA is already being included in management strategies by conservation groups. However, she said the findings described in the new paper represent the early stages of what can be gleamed from the marsupial's genome.

    "The data is public, and I would love for anyone to start mining it and see what other amazing things they can find," she said." Once you have a genome of this quality, the sky's the limit with what you can do with it."