How much weight a baby gains during its first month could determine its IQ, as a new research suggests. The study found that children who gain more weight, and whose heads grow quickly during the first month of life, tend to have a higher IQ when they start school.

    Researchers at the University of Adelaide, in Australia^ studied 13,800 children who were born at full-term. They found that those who put on 40% of their birth weight in the first four weeks had an IQ 1.5 points higher than those who only put on 15% of their birth weight. Those who experienced the biggest growth in head circumference (头围) also had the highest IQs by the age of six.

“Head circumference is an indicator of brain volume, so a greater increase in head circumference in a newly-born baby suggests more rapid brain growth,” says the led author of the study, Dr. Lisa Smithers.

    She added, “Overall, newly-born children who grew faster in the first four weeks had higher IQ scores later in life. Those children who gained the most weight scored especially high on verbal (言语) IQ at age 6. This may be because the neural (神经的) structures for verbal IQ develop earlier in life, which means the rapid weight gain during the first month could be having a direct cognitive benefit for the children.”

    Previous studies have shown the association between early postnatal (产后的) diet and IQ, but this is the first study of its kind to focus on the IQ benefits of rapid weight gain in the first month of life. Dr. Smithers says the study further highlights the need for successful feeding of newly-born babies. “We know that many mothers have difficulty establishing breastfeeding in the first week of their babies' life,” Dr. Smithers said.

    “The findings of our study suggest that if babies are having feeding problems, there needs to be early intervention (干预) in the management of that feeding.”

    The past two decades have seen astronomers' catalogue of planets expand over two hundred times, as new techniques and better telescopes have found more than 2,000 of them orbiting stars other than the sun. But in the solar system itself, the list of planets has actually shrunk, Pluto（冥王星）having been downgraded from that status in 2006. The number of the sun's planetary companions has thus fallen from nine to eight.

    Now, a pair of astronomers from the California Institute of Technology think they have evidence that will restore the sun's record to its previous value. Their analysis of objects orbiting in the Kuiper Belt（柯伊伯带）, a ring of frozen asteroids（小行星）that circle beyond the orbit of Neptune (and of which Pluto is now regarded as the largest member), suggests to them that something about ten times as massive as Earth has changed those orbits. If you knew where to look, this planet-sized object would be visible through a suitable telescope. And Konstanin Batygin and Michael Brown believe they do know.

As they write in the Astronomical journal, they have analyzed the orbits of Kuiper Belt objects and found six that behave in a peculiar way. As the diagram shows, the points of closest approach of these objects to the sun, known as their perihelia（近日点）, almost coincide. Moreover, these perihelia all lie near the ecliptic（黄道）—the plane of Earth's orbit and also, approximately, that of the other planets—while the objects' orbits are all angled at 30° below the ecliptic. The chance of all this being a coincidence, the two researchers estimate, is about seven in 100,000. If it is not a coincidence, it suggests the six objects have been guided into their orbits by the gravitational intervention of something much larger.

    A computer analysis Dr Batygin and Dr Brown performed suggests this something is a planet weighing 5-15 times as much as Earth, whose perihelion is on the opposite side of the sun from the cluster, and which thus orbits mainly on the other side of the solar system from the objects its orbit has affected. This planet's perihelion would be 200 times farther from the sun than Earth's, and the far end of its orbit might be as much as six times that distance away. This gives a search zone, and Dr Batygin and Dr Brown are using Subaru, a Japanese telescope, to perform that search.

    Given other demands on Subaru's time, it might take five years for this search to find (or not find) the hypothetical planet. But looking at some existing data from. The Widefield Infrared Survey Explore, a satellite, might also show it, if it is there to be seen.

    Ironically, it was Dr Brown as much as anyone who was responsible for Pluto's downgrading, for he discovered Eris, an object almost as big as Pluto, in 2005.

    That discovery did much to damage Pluto's planetary proof. By his own admission, he was skeptical that the anomalies he and Dr Batygin have investigated actually would point to the existence of a replacement ninth planet. He is a skeptic no longer. Whether he is actually right may soon become apparent.

    If you're new to San Francisco, paying the city a visit, or simply looking for a new playground for you and your dog, here are four of the finest dog parks in San Francisco.

    Corona Heights Dog Park

    Often visited by residents from all over the city because of its nearness to the Randall Museum, Corona Heights Dog Park offers pets and owners breathtaking views, after a steep hillside climb, and a fenced dog area that allows dogs to let loose without a leash （狗链）. Owners will also enjoy the playground, tennis courts and basketball courts.

    Dolores Dog Park

    The grounds of Dolores Park once served as camps for those who were left homeless by the 1906 earthquake, but now often visited by crowds of Mission District people. Four-legged friends can also wander about carefree off-leash while making friends with other members of the doggie community.

    Pine Lake Dog Park

    Noteworthy for its place as a rest stop for hundreds of species of birds to fly to and from warmer climates, Pine Lake Park is also prized by city dogs and their owners for their nice hiking paths, picturesque lake suited for swimming, and an off-leash area on the park's west end that lets dogs run free.

    Buena Vista Dog Park

    At 146 years young, Buena Vista Park is San Francisco's oldest park. Dogs and owners with plus energy will love burning it on this park's steep paths and winding staircases. Dog owners should have good control over their dogs, as it's quite easy for dogs to get separated when going through Buena Vista's many twists and turns.

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    Every summer, my family and I visit our relatives in India and whenever we travel, my parents always remind me to drink only bottled or boiled water. On one of my trips to India, I saw children drinking water from the roadside. I was troubled to learn that millions of people, most of them children in developing countries, die each year because of water related diseases.

    Living in the US, I am lucky to be able to turn on the tap and get potable water(饮用水), while one sixth of the world's population lacks access to clean water This year, I entered the Discovery Education 3M Young Scientist Challenge. In late June, I learned that I was selected as one of the top 10 national finalists of this famous middle school science competition. Over the summer, I worked with Dr. Jim Jonza, my Scientist mentor(导师 )from 3M, and developed a system that uses solar energy to purify water. My invention is green and cost effective, and I am looking forward to implementing this in places that are affected(影响)by harmful water pollution.

    In October, my family and I flew to 3M Headquarters in St Paul, Minnesota, where the final event was to be held. For the last challenge, each of us had to present the invention we had been working on over the summer. The first place winner would win $25,000, a trip to Costa Rica, and the title of America' Top Young Scientist. At the awards ceremony, all of us waited anxiously until one of the judges, Danny Forester, started announcing "The winner of the Discovery Education 3M Young Scientist Challenge is…" You could hear a pin(大头针) drop as he opened the paper with the winner' s name, "Deepika Kurup!"

    As America's Top Young Scientist, I was given an opportunity to show my invention on national television and deliver several presentations. One of the most important things I have learned is that communication and teamwork are key to success.