Motherhood may make women smarter and may help prevent dementia (痴呆) in old age by bathing the brain in protective hormones (荷尔蒙) , U.S. researchers reported on Thursday.

    Tests on rats show that those who raise two or more litters of pups do considerably better in tests of memory and skills than rats who have no offsprings, and their brains show changes that suggest they may be protected against diseases such as Alzheimer's (早老痴呆症). University of Richmond psychology professor Craig Kinsley believes his findings will translate into humans.

“Our research shows that the hormones of pregnancy are protecting the brain, including estrogen(雌激素), which we know has many neuroprotective (保护神经的) effects,” Kinsley said.

    “It's rat data but humans are mammals just like these animals are mammals,” he added in a telephone interview. “They go through pregnancy and hormonal changes.”

    Kinsley said he hoped public health officials and researchers will look to see if having had children protects a woman from Alzheimer's and other forms of age-related brain decline.

    “When people think about pregnancy, they think about what happens to babies and the mother from the neck down,” said Kinsley, who presented his findings to the annual meeting of the Society of Neuroscience in Orlando, Florida.

    “They do not realize that hormones are washing on the brain. If you look at female animals who have never gone through pregnancy, they act differently toward young. But if she goes through pregnancy, she will sacrifice her life for her infant—that is a great change in her behavior that showed in genetic alterations to the brain.”

    For the first time, China's South Pole researchers can eat fresh vegetables grown regularly, according to Wang Zheng, the grower, who came home last month after a 400-day mission in Antarctica.

    "Growing vegetables in Antarctica reminded me of The Martian, a sci-fi movie about an astronaut who survives alone on Mars by eating potatoes he grows there," Wang said on Friday. "I totally understand the main character of the movie, I understand how he feels when he watches a small green plant grow in a fragile man-made environment,'' said the 40-year-old doctor. But he admitted that the conditions he faced in the Antarctic were much better than those in the film.

    Wang said the growth chamber(生长室) at the Zhongshan Station, had only a low yield when it was established in 2013. The amount was too small to make it possible for researchers to have vegetable dishes. To increase the yield, he reduced the number of vegetable varieties and focused on only some fast-growing ones, which makes the output stable. As a result, during much of his stay there, at least one vegetable dish, such as cucumbers, lettuce or cabbage, was served at every meal for a group of 18 researchers.

    Wang, an orthopedist, said he knew nothing about botany or farming before he arrived at the station in December, 2014. "I was given this job probably because my office is next to the growth chamber, and as a doctor, I had more spare time than others," Wang said. He considered many factors, such as light, temperature and humidity. Light music is played in the 16-square - meter greenhouse around the clock. "Mild music is good for vegetable growth," he said. "We also played Buddhist music, which has soft melody."

    "Growers before me did very good work. My job was to maintain the chamber and keep everything working." Before the  harvest, researchers had a very limited vegetable supply—mostly potatoes and cabbage, which taste awful after months of storage. "Because of our success in growing vegetables, we can have fresh vegetables every day," he said. "The Russian station is no more than one kilometer away from ours. We even had enough vegetables to invite our Russian colleagues for dinner."

    If you cannot afford to travel in any class above economy, flying generally sucks, either a little or a lot, depending on your tolerance level. But it especially sucks if you are too wide for the airline's design.

    Just getting to your seat can be a challenge, as your hips (臀部，髋) bounce from seat to seat on each side of the aisle (过道). If someone is standing up to put things in the overhead locker, there is a decision to be made about whether it's worth trying to squeeze past. Everything is just slightly too small: the seats, the overhead lockers, even the bathrooms—and those, it seems, are getting even smaller.

    The Washington Post recently reported that, on some newer planes flown by American, Delta and United airlines, the bathrooms in economy class are just 61cm wide: about 25cm narrower than the average portable toilet, and roughly the width of the average dishwasher. Your face might be the only thing you can poke in there comfortably—which makes it a poor design, considering what a passenger is likely to need the bathroom for.

    According to the manufacturer, these "Advanced Spacewell" bathrooms make space for six additional passengers, which is great for the airlines' financial bottom line. But what about the other bottom line? Concerning, well, bottoms that can't fit into their planes' bathrooms?

    As bodies get bigger and aeroplane spaces get smaller, the wide among us have come up with solutions. Armrests that turn us into sausages (香肠) can be pulled up, or slowly encased (围住，包起) into the soft flesh of our sides until we go numb (麻木). We can ask the flight attendant to get us a seat-belt extender, if security has confiscated the one we brought with us, as can sometimes happen. But squeezing into a tiny toilet and closing the door behind us? Not workable.

    Unlike the impossible task of squeezing down the aisle to your seat, or the side-to-side dance necessary to get big hips past the armrests, fitting into a space just 61cm wide is not just a challenge—it is almost impossible. It is not like missing out on an option for the in-flight meal—a bathroom is as essential as a safety-compliant seat belt, or the air that is pumped in to the cabin (飞机舱). If airlines are not willing to make space for us, bigger passengers may have no option but to reconsider booking a flight at all.

    Why elephants rarely get cancer is a mystery that has confused scientists for decades. A study was led by researchers at Huntsman Cancer Institute (HCI) at the University of Utah and Arizona State University, including researchers from the Ringling Bros. Center for Elephant Conservation may have found the answer. According to the results, elephants have 38 additional modified copies of a gene (基因) that encodes p53, a well-defined tumor (肿瘤) suppressor, as compared to humans, who have only two. Further, elephants may have a more powerful mechanism for killing damaged cells that are at risk for becoming cancerous. In isolated elephant cells, this activity is doubled compared to healthy human cells, and five times that of cells from patients with Li-Fraumeni Syndrome, who have only one working copy of p53 and more than a 90 percent lifetime cancer risk in children and adults. The results suggest extra p53 could explain elephants' increased resistance to cancer.

    "Nature has already figured out how to prevent cancer. It's up to us to learn how different animals overcome the problem so we can adapt those strategies to prevent cancer in people," says co-senior author Joshua Schiffman, M.D., pediatric oncologist (肿瘤学家) at Huntsman Cancer Institute, University of Utah School of Medicine, and Primary Children's Hospital.

    According to Schiffman, elephants have long been considered a walking problem. Because they have 100 times as many cells as people, they should be 100 times more likely to have a cell slip into a cancerous state and cause the disease over their long life span of 50 to 70 years. And yet it's believed that elephants get cancer less often, a theory confirmed in this study. Analysis of a large database of elephant deaths estimates a cancer death rate of less than 5 percent compared to 11 to 25 percent in people.

    According to a team of researchers, an animal's ability to perceive(感知)time is linked to their pace of life.

    "Our results lend support to the importance of time perception in animals where the ability to perceive time in a very short time may be the difference between life and death for fast moving creatures." commented lead author Kevin Healy from Trinity College Dublin.

    The study was done with a variety of animals using phenomenon based on the maximum speed of flashes of light an individual can see before the light source is seen as constant. Dogs, for example, have eyes with a refresh rate higher than humans.

    One example of this phenomenon at work, the authors say, is the housefly and its ability to avoid being hit. The research showed flies "observe motion in a shorter time than our own eyes can achieve, "which allows them to avoid being hit.

    Professor Graeme Ruxton of the University of St Andrews in Scotland, who worked jointly on the research project, said in a statement, "Having eyes that send updates to the brain at much higher frequencies than our eyes do is of no value if the brain cannot process that information equally quickly. Thus, this work highlights the impressive abilities of even the smallest animal brains. Flies might not be deep thinkers, but they can make good decisions very quickly."

    In comparison, the tiger beetle(虎甲虫)runs faster than its eyes can keep up, basically becoming blind, which requires it to stop periodically to re-evaluate its prey's(猎物)position.

    Our results suggest that time perception offers an as yet unstudied dimension along which animals can specialize and there is considerable range to study this system in more detail.