Here, sleep experts clear up some of the biggest misunderstandings about sleep they see with their patients, which could weaken your ability to have a night of good sleep.

Myth: {#blank#}1{#/blank#}

    The latest research shows that the right amount of sleep may vary from person to person and should leave you feeling energized the next day. I'm a sleep doctor. Take myself for example. {#blank#}2{#/blank#}.

Myth: Don't fall asleep with the TV on.

    I've cured more people suffering from sleep problems than you can imagine by telling  people it's OK to fall asleep with the TV on. {#blank#}3{#/blank#}Control the watching time so it doesn't affect your sleep later in the night.

Myth: You can catch up on lost sleep on the weekend.

    {#blank#}4{#/blank#} A Harvard study found that even if you sleep for an extra 10 hours on the weekend to make up for only sleeping six hours a night for two weeks, those extra hours won't improve  your reaction times or ability to focus. Plus, sleeping late throws off your biological clock, which can lead to obesity, diabetes, and heart disease.

Myth: Alcohol can help you rest easy.

    {#blank#}5{#/blank#} Alcohol may relax you so you nod off quicker, but studies show you'll wake up more and get less of deep sleep you need to feel rested.

    Greece's finance minister says his country's financial situation is “terribly urgent” and the crisis could come to a head in a couple of weeks. Yanis Varoufakis gave the warning after eurozone finance ministers met in Brussels to discuss the final €7.2bn tranche(援助资金) of Greece's €240bn EU/IMF bailout(紧急援助).

    Ministers said Greece had made “progress” but more work was needed.

The Greek government is struggling to meet its payment obligations（责任）.Earlier, Greece began the transfer of €750m (£544m, $834m) in debt interest to the International Monetary Fund - a day ahead of a payment deadline.

    “The liquidity（资产流动性） issue is a terribly urgent issue. It's common knowledge, let's not beat around the bush,” Mr Varoufakis told reporters in Brussels. “From the perspective of timing, we are talking about the next couple of weeks.”

    Greece has until the end of June to reach a reform deal with its international creditors. Its finances are running so low that it has had to ask public bodies for help. The crisis has raised the prospect that Greece might default（违约） on its debts and leave the euro.

    In a statement, the eurozone finance ministers said they “welcomed the progress that has been achieved so far” in the negotiations,” but added: “We acknowledged that more time and effort are needed to bridge the gaps on the remaining open issues.” Eurogroup chairman Jeroen Dijsselbloem said there had to be a full deal on the bailout（紧急财务援助） before Greece received any further payments. “There are time constraints(限制；约束) and liquidity constraints and hopefully we will reach an agreement before time runs out and before money runs out.” he said.

    There had been fears that Greece would default on its IMF debt repayment due on Tuesday. However, a Greek finance ministry official was quoted as saying that the order for repayment had been executed（实施） on Monday. Almost €1bn has been handed over to the IMF in interest payments since the start of May.

    It is unclear how the government came up with the funds, but the mayor of Greece's second city Thessaloniki revealed last week that he had handed over cash reserves in response to an appeal for money.

    Spending money on a vacation may seem like a luxury（奢侈品）—but occasionally, you have to relax yourself. Here's where to go for a good time at an unbelievable value.

    Captiva Island, Florida

    Keep it simple by looking for seashells, or bicycling, jet skiing; you can even hit the tennis courts. The Summer Getaway package offers a fourth night free and rates from $209 a night, making the average for a four-night stay $157.Kids 12 and under eat breakfast free. You'll get a coupon（优惠券）book with more than $250 in savings on resort outlets（经销店）, from watersports, island cruises and more.

    Reyjavik, Iceland

    STA Travel Beats specializes in taking travelers to music festivals around the globe. It has an eight-day tour, Icelandic Beats, that takes you to the Icelandic Geothermal spas（水疗）, UNESCO world heritage sites, and black sand beaches. End your vacation at the Secret Solstice Festival on June 18. The tour is $1,218,not including airfare.

    Malpais, Costa Rica

    You get daily surfing instruction, sunset surf session, and yoga in the outdoor, oceanfront yoga studio in a week-long tour. As you get mind, body, and spirit together, keep it going with healthy meals at the beachfront restaurant. Prices are $2,895 for shared accommodations, $3,095 for private accommodations with shared bath, and $3,595 for private accommodations.

    Waterville Valley, New Hampshire

    Waterville Valley Resort is surrounded by 100 miles of trails in the White Mountain National Forest. If you get a Freedom Pass, you can save about $100 a day during a six-day tour; the pass enables you daily to have a two-hour mountain bike rental, unlimited tennis, a round of golf, and a kayak, canoe, or paddleboard rental. Rates start at $139 a night.

    People with bigger brains tend to score higher on standardized tests of intelligence, according to new study findings.

    However, the study author Dr. Michael A.McDaniel of the Virginia Commonwealth University in Richmond emphasized that these findings represent a general trend, and people with small heads should not automatically believe they are less intelligent. For instance, Albert Einstein's brain was "not particularly large", McDaniel noted." There's some relationship between brain size and intelligence on the average, but there's plenty of room for exceptions," he said.

    Interest in the relationship between brain size and intelligence grew in the1830s, when German anatomist(解剖学家) Frederich Tiedmann wrote that he believed there was "an unquestionable connection between the size of the brain and the mental energy displayed by the individual man". Since that statement, scientists have conducted numerous studies to determine if Tiedmann's assertion was correct. Most studies have looked into the link between head size and intelligence. More recently, however, researchers have published additional studies on brain size and intelligence, measured using MRI scan(核磁共振成像扫描).

    For his study, McDaniel analyzed more than 20 studies that looked into the relationship between brain size and intelligence in a total of 1,530 people. The studies showed that on the average, people with larger brain volume tended to be more intelligent. The relationship between brain volume and intelligence was stronger in women than men, and in adults than in children. McDaniel notes in the journal Intelligence.

    McDaniel is not sure why the relationship was stronger for adults and women. "Other research has shown that women, on the average, tend to have smaller brains than men, but score just as well—if not higher—in tests of intelligence," he said.

    McDaniel insisted that the relationship between brain size and intelligence is not a "perfect" one. "One can certainly find lots of examples of smaller-sized people who are highly intelligent," he said, "But, on the average, the relationship holds."

    There is some unwelcome news for students preparing for exams and officers putting in long hours—you don't need that "refreshment（提神） break" as much as you may think.

    Scientists believed it was not easy for people to continue their work if they felt the need to have a snack or a rest to make them feel better. They argued that the only way to regain willpower is by supplying more energy to our bodies with rest, food or entertainment.

    But psychologists have challenged this theory, saying weak willpower is in your head. They found that a person's mindset(理念) and belief about willpower determine how long and how well they'll be able to work on a tough mental exercise. "If you think of willpower as something that's limited, you're more likely to be tired when you perform a difficult task," said Professor Veronika Job. "But if you think of willpower as something that is not easily depleted, you can go on and on."

    The researchers led by Mr. Job designed an experiment to test the students' beliefs about willpower. After a tiring task those who believed or were led to believe that willpower was a limited resource performed worse on standard concentration tests than those who thought of willpower as something they had more control over.

    Mr. Job said, "Students who may already have trouble studying are being told that their powers of concentration are limited, and they need to take frequent breaks. But a belief in willpower as a non-limited resource makes people stronger in their ability to work through challenges."

    The findings could help people who are battling with temptation(诱惑): people following strict diets and doing exercise regularly to lose weight, people trying to overcome addictions, employees facing a tight deadline. Willpower isn't driven by a biologically based process as much as we used to think.

    The ocean bottom, a region nearly 2.5 times greater than the total land area of the earth, is even today largely unexplored. Until about a century ago, the deep ocean floor was completely inaccessible and hidden beneath waters averaging over 3,600 meters deep. Totally without light and in the case of intense pressures hundreds of times greater than at the earth's surface, the deep-ocean bottom is a strange environment to humans, in some way, as fighting and remote as the outer space.

Although researchers have taken samples of deep-ocean rocks for over a century, the first detailed global study of the ocean bottom did not actually start until 1969, with the beginning of the National Science Foundation's Deep Sea Drilling Project(DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP's drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean's surface and drill very deep waters, taking samples of rocks from the ocean floor.

    The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, it sailed 600,000 kilometers and took almost 20,000 samples of rocks around the world. Those samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to make out what it will probably look like millions of years in the future. Today, largely on the strength of evidence gathered during the Glomar Challenger's voyages, nearly all earth scientists agree on the theories of plate tectonics (构造学) and continental drift that explain many of the geological processes.

    The sample of rocks drilled by the Glomar Challenger has also provided a climatic record stretching back hundreds of millions of years. The information of past climatic change can be used to predict the future climate.