The vast majority of us spend our entire lives pulled down by gravity. Then there are astronauts.

This small population of space travelers has given researchers a rare look at what happens to the human body when it's able to spend large amounts of time outside the downward pull of the Earth. This week, a study on one of the largest groups of astronauts yet —34 participants—was published in The New England Journal of Medicine.

    In the new study, a team of international radiologists supported by NASA looked at MRIs of the brains of astronauts before and after their trips to space. The scientists found that upon returning to Earth, many of the astronauts' brains had become repositioned inside their skulls, floating higher than before. In addition, the space between certain brain areas appeared to have shrunk. The changes were more common in astronauts who took longer trips into space.

    The team characterized astronaut trips as short (an average of less than 14 days) or long (an average of about 165 days). Radiologists who didn't know each astronaut's duration（持续时间）in space compared MRIs from before and after their trips.

    Of the 34 total astronauts involved in the study, 18 took long trips to space—spending most of that time on the International Space Station —and of those, 17 returned to Earth with smaller areas between the frontal lobe（脑前额叶）and parietal lobe（顶叶）. The same area of the brain also shrank for three of the 16 astronauts who took shorter trips with the US Space Shuttle Program. The researchers also found that 12 of the ISS astronauts and six of the space-shuttle astronauts returned home with their brains sitting slightly higher in their skulls than before.

    It's not clear what, if anything, these brain changes mean for the health of space travelers. In general, it appears the human body tolerates space travel fairly well: the time astronauts have spent in zero-gravity environments so far doesn't seem to have had any strong or long-lasting effects.

    CHICAGO -- New research on vegetables and aging gives mothers another reason to say "I told you so." It is found that eating vegetables appears to help keep the brain young and may slow the mental decline（下降） sometimes associated with growing old.

    On measures of mental sharpness, older people who ate more than two servings of vegetables daily appeared about five years younger at the end of the six-year study than those who ate few or no vegetables.

    The research in almost 2,000 Chicago-area men and women doesn't prove that vegetables reduce mental decline, but it adds to mounting evidence pointing in that direction. The findings also echo（回应） previous research in women only.

    Green leafy vegetables including spinach（菠菜）, kale and collards （甘蓝） appeared to be the most beneficial. The researchers said that may be because they contain healthy amounts of vitamin E, an antioxidant（抗氧化剂） that is believed to help fight chemicals produced by the body that can damage cells.

    Vegetables generally contain more vitamin E than fruits, which were not linked with slowed mental decline in the study. Vegetables also are often eaten with healthy fats such as salad oils, which help the body absorb vitamin E and other antioxidants, said lead author Martha Clare Morris, a researcher at the Rush Institute for Healthy Aging at Chicago's Rush University Medical Center.

    The fats from healthy oils can help keep cholesterol（胆固醇）low and arteries （动脉）clear, which both contribute to brain health. The study was published in this week's issue of the journal Neurology and funded with grants from the National Institute on Aging.

    While it's books that make a library, being in lovely surroundings may provide inspiration and help you work a little bit harder. Here are some of the coolest libraries of the world.

    Library of Birmingham – Birmingham, U.K.

    The new Library of Birmingham is said to be not only Britain's biggest public library, but also the largest in Europe. Designed by Dutch architects, this replacement for the Birmingham Central Library was opened in 2013 and has a wealth of resources within its walls, including adults and kids' libraries, music collections, a Shakespeare Memorial Room, and even a gym room. Gardens crown the roof, while the changing seasons bring variations in the shadows and reflections inside.

    National Library of France – Paris, France

    The National Library of France, which now contains an astonishing collection of 30 million, dates back to the 14th century and this royal library was set up at the Louvre by King Charles V. The Library was moved to Rue de Richelieu site in 1868, with major design work carried out by French architects Henri Labrouste and, following his death, Jean-Louis Pascal. Here, the reading rooms are elegance itself. There are more than just books to be found.

    State Library of New South Wales – Sydney, Australia

    The public State Library of New South Wales holds the honor of being the oldest institution of its kind in Australia. It was originally set up as the Australian Subscription Library in 1826, but it wasn't until 1942 that its permanent home was ready. Designed by Sydney architect Walter Liberty Vernon and completed in 1910, the magnificent sandstone Mitchell Wing is one of the architectural highlights.

Seattle Central Library – Seattle, Washington, USA

    Seattle Central Library's distinctive design ensures it stands out. Architect Rem Koolhaas is one of the names attached to its design. Architects sought to envelop the 11-story building with “a layer of transparency”, using a skin of glass and metal. The finished article houses about 1.45 million books and other things, as well as more than 400 computers available for public use. The building, which opened in 2004, was included on the American Institute of Architects' list of America's 150 favorite buildings in 2007.

Music

    Opera at Music Hall: 1243 Elm Street. The season runs June through August, with additional performances in March and September. The Opera honors enjoy the Arts membership discounts. Phone: 723­1182.

    Chamber Orchestra: The Orchestra plays at Memorial Hall at 106 Elm Street, which offers several concerts from March through June. Call 241­2742 for more information.

    Symphony Orchestra: At Music Hall and Riverbend. For ticket sales, call 381­3300. Regular season runs September through May at Music Hall and in summer at Riverbend.

    College Conservatory of Music (CCM): Performances are on the main campus (校园) of the university, usually at Patricia Cobbett Theater. CCM organizes a variety of events, including performances by the well­known LaSalle Quartet, CCM's Philharmonic Orchestra, and various groups of musicians presenting Baroque through modern music. Students with I.D. cards can attend the events for free. A free schedule of events for each term is available by calling the box office at 556­4183.

    Riverbend Music Theater: 6295 Kellogg Ave. Large outdoor theater with the closest seats under cover (price difference) .Big name shows all summer long! Phone: 232­6220.

The teenage Snowboarder.

I was born in Denver, USA. and started snowboarding aged eight when my dad took me to a resort in the mountains. About two hours from Denver. The hill looked unbelievably steep and scary. So My dad had to do a lot of persuading to get me on a board. Because I was so young. I hadn't even thought of asking him if I could start snowboarding? But he was already into it and wanted me to love it, too—-He made it look so simple, and in the end I managed just fine.

After this experience, it wasn't long before I'd developed a love of sport and had improved my ability too. I started competing aged ten. Some people entered loads of competitions and ended up getting bored of snowboarding. But my love of taking part and winning got stronger as I got older, which always help me to push myself harder. I enjoyed not having a fixed plan and sometimes this went well, like when I became the first female ever to get a perfect 100 at a local competition. I wasn't sure I'd even attempted the jumps that got me the score until I actually set off. That achievement increased my trust in my own abilities.

During the summer I focused on training and my studies while there's no snow. Although I trained daily, it's nice not having to stick to quite a strict diet like I did in the winter. I also got to spend lots of time with my friends then. It's the best way of dealing with not being able to do what I loved so much and what I was really good at.

Now. I have to think carefully about my future. Snowboarding is such a huge part of my life now. But I also feel it's important to have something else I can do. just in case I don't succeed as a professional snowboarder or I get injured. I'm wondering whether becoming a doctor is a possibility. if my active life allows time for doing a college degree, it's impossible to imagine myself growing tired of the sport. But I can't go on snowboarding my whole life.