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    Measles(麻疹), which once killed 450 children each year and disabled even more, was nearly wiped out in the United States 14 years ago by the universal use of the MMR vaccine(疫苗). But the disease is making a comeback, caused by a growing anti-vaccine movement and misinformation that is spreading quickly. Already this year, 115 measles cases have been reported in the USA, compared with 189 for all of last year.

    The numbers might sound small, but they are the leading edge of a dangerous trend. When vaccination rates are very high, as they still are in the nation as a whole, everyone is protected. This is called “herd immunity”, which protects the people who get hurt easily, including those who can't be vaccinated for medical reasons, babies too young to get vaccinated and people on whom the vaccine doesn't work.

    But herd immunity works only when nearly the whole herd joins in. When some refuse vaccination and seek a free ride, immunity breaks down and everyone is in even bigger danger.

    That's exactly what is happening in small neighborhoods around the country from Orange County, California, where 22 measles cases were reported this month, to Brooklyn, N.Y., where a 17-year-old caused an outbreak last year.

    The resistance to vaccine has continued for decades, and it is driven by a real but very small risk. Those who refuse to take that risk selfishly make others suffer.

    Making things worse are state laws that make it too easy to opt out(决定不参加) of what are supposed to be required vaccines for all children entering kindergarten. Seventeen states allow parents to get an exemption（豁免), sometimes just by signing a paper saying they personally object to a vaccine.

    Now, several states are moving to tighten laws by adding new regulations for opting out. But no one does enough to limit exemptions.

    Parents ought to be able to opt out only for limited medical or religious reasons. But personal opinions? Not good enough. Everyone enjoys the life-saving benefits vaccines provide, but they'll exist only as long as everyone shares in the risks.

    Have you ever considered why you begin yawning too when you see someone yawn? Or how hard it is to be among people laughing and not laugh yourself? Well, apparently it's because we have mirror neurons (神经元）in our brains.

    Put simply, the existence of mirror neurons suggests that every time we see someone else do something, our brains imitate it whether or not we actually perform the same action. This explains a great deal about how, we learn to smile, talk, walk, dance or play sports. But the idea goes further: mirror neurons not only appear to explain physical actions, they also tell us that there is a biological basis for the way we understand other people.

    Mirror neurons can undoubtedly be found all over our brains, but especially in the areas which relate to our ability to use languages, and to understand how other people feel. Researchers have found that mirror neurons relate strongly to language. A group of researchers discovered that if they gave people sentences to listen to ( for example: “The hand took hold of the ball” ) , the same mirror neurons were triggered as when the action was actually performed (in this example, actually taking hold of a ball).

    Any problems with mirror neurons may well result in problems with behavior. Much research suggests that people with social and behavioral problems have mirror neurons which are not fully functioning. However, it is not yet known exactly how these discoveries might help find treatments for social disorders.

    Research into mirror neurons seems to provide us with even more information regarding how humans behave and interact. Indeed, it may turn out to be the equivalent (相等物）for neuroscience of what Einstein's theory of relativity was for physics. And the next time you feel the urge to cough in the cinema when someone else does — well, perhaps you'll understand why.

    NGS Scholarship (NGSS)

    The NGS Scholarship is awarded to talented students with a strong interest in innovative(创新的) PhD research.

    Terms:

    Monthly stipend(津贴) of $3,200 for up to 4 years of PhD studies, or up to date of graduation, whichever is earlier.

    Payment of full tuition(学费) fees for up to 4 years of PhD or up to date of graduation, whichever is earlier.

    Other allowances include:

    Computer allowance

    Book allowance

    Conference allowance

    Eligibility(资格):

    Open worldwide.

    Graduates should have an affection for research.

    Graduates should hat at least Upper 2nd Class Honors, or equal qualification.

    GRE is compulsory（必须做的，义务的） for students applying from overseas.

    TOEFL is compulsory (ONLY) for applicants whose native tongue or medium of undergraduate instruction is not in English).

    Application:

    Click here to apply online.

    All supporting documents, together with a printed copy of the application form are to be submitted (提交) by post to :

    NUS Graduate School for Integrative Sciences & Engineering (NGS)

    Center For Life Sciences (CeLS)

    28 Medical Drive, #05-01

    ONLY Online Applications are accepted.

    Closing date: 15May 2017.

    Something's happening at the lowest point on our planet.

The Dead Sea, a salt lake bordered by Jordan to the east and Israel and Palestine to the west, is shrinking(缩小) at an alarming rate—--about 3.3 feet per year, according to the environmentalist group EcoPeace Middle East. And human actions are largely to blame.

    “It's not just like one country is punishing the Dead Sea; it's more like the whole area,” said photographer Mortize Kustner, who visited the area in February to work on his series “The Dying Dead Sea”.

    The Dead Sea needs water from the other natural sources surrounding it, such as the Jordan River basin. But around the 1960s, some of the water sources it relied on were diverted(使改道).Israel, for instance, built a pipeline during that time so it could supply water throughout the country.

    Mineral extraction(开采) industries are another main reason the water levels are falling, experts say. The Dead Sea's minerals have been used as medicine and can often be found in cosmetics(化妆品) and other consumer products.

    And then, of course, there's the Middle East's hot, dry climate, which makes it difficult for the lake to replenish itself.

    Last year, Israel and Jordan signed a $900 million deal in an effort to keep the Dead Sea's water levels stable（稳定）. It includes building a canal from the Red Sea to the Dead Sea which would be able to not only supply water to Israel and Jordan but also to pump water into the Dead Sea.

    But for now, Kustner shows us that the Dead Sea remains very much a place of interest, with people from all over the world going there to swim in its salty waters.

    The Dead Sea, known as the Salt Sea in the language of Hebrew, is one of the saltiest bodies of water in the world. And because of what has been happening over the years, the salt is only getting saltier.

    Scientists have created a scent(气味)-delivery system that releases a pleasant fragrance when you sweat. Apply it to your skin, and the more you sweat, the better you'll smell. That's because the perfume only gets released upon contact with moisture(湿气).

Chemists from Harvard University combined two compounds to create their new system. One chemical is alcohol-based. This is the nice-smelling perfume. The other chemical is an ionic liquid(离子性液体), which is a type of salt that is liquid at room temperature. Ionic liquids are made of ions—molecules(分子) that have lost or gained one or more electrons(电子). If the molecule loses electrons, it will have a positive charge(正电荷). If it gains electrons, it gets a negative charge. Ionic liquids contain the same number of positive and negative ions, which makes them neutral, with no overall electric charge. In general, ionic liquids have no smell.

    When the perfume and ionic liquid are mixed together, a chemical reaction occurs. This bonds the molecules to each other. The reaction also temporarily inactivates the perfume's molecules. So when applied to the skin, the new perfume has no scent in the beginning. But adding water or sweat breaks the bond between the molecules. That releases the scent into the air.

    "The rate of the release of the fragrance depends on how much you sweat, in other words, how much water is available," explains chemist Nimal Gunaratne from Harvard University, who led the research. "Sweat is like the command to let the fragrance go."

    Christian Quellet is a chemist who has worked in the perfume industry for a long time. He is now an independent consultant based in Switzerland. "Gunaratne's perfume opens the door to new developments and applications of fragrance controlled-release systems," he says. Controlled-release systems allow small quantities of some compounds that they hold to enter the environment slowly.

    The system also traps some chemicals in sweat that are responsible for the bad sweat smell. These compounds are called thiols (硫醇). Just as water does, thiols break apart the bond that ties the perfume to the ionic liquid. When this happens, the thiols attach to the ionic liquid and their bad scent is inactivated as the perfume had been. This means the water in sweat and its thiols are both able to release the fragrance from the newly developed perfume.