People with a rare genetic disorder known as Prader-Willi syndrome never feel full, and this excess hunger can lead to life-threatening obesity (肥胖症). Scientists studying the problem have now found that the fist-shaped structure known as the cerebellum (小脑) — which had not previously been linked to hunger — is key to regulating satiation (饱食) in those with this condition.

This finding is the latest in a series of discoveries revealing that the cerebellum, long thought to be primarily involved in movement harmony, also plays a broad role in cognition, emotion and behavior. “We’ve opened up a whole field of cerebellar control of food intake,” says Albert Chen, a neuroscientist at the Scintillon Institute in California.

The project began with an accidental observation: Chen and his team noticed they could make mice stop eating by activating small pockets of neurons (神经元) in regions known as the anterior deep cerebellar nuclei (aDCN), within the cerebellum. Fascinated, the researchers gathered data using functional MRI to compare brain activity in 14 people who had Prader-Willi syndrome with activity in 14 unaffected people while each testee viewed images of food -- either immediately following a meal or after fasting (禁食) for at least four hours.

New analysis of these scans revealed that activity in the same regions Chen’s group had accurately pointed out in mice, the aDCN, appeared to be significantly disturbed in humans with Prader-Willi syndrome. In healthy individuals, the aDCN were more active in response to food images while fasting than just after a meal, but no such difference was identifiable in participants with the disorder. The result suggested that the aDCN were involved in controlling hunger. Further experiments on mice, conducted by researchers from several different institutions, demonstrated that activating the animals’ aDCN neurons dramatically reduced food intake by weakening how the brain’s pleasure center responds to food.

For years neuroscientists studying appetite focused mainly either on the hypothalamus, a brain area involved in regulating energy balance, or on reward-processing centers such as the nucleus accumbens (伏隔核). But this group has identified a new feeding center in the brain, says Elanor Hinton, a neuroscientist at the University of Bristol in England who was not involved with the study. “I’ve been working in appetite research for the past 15 years or so, and the cerebellum has just not been a target,” Hinton says. “I think this is going to be important both for Prader-Willi syndrome and, much more widely, to address obesity in the general population.”

In the early 1960s Wilt Chamberlain was one of only three players in the National Basketball Association (NBA)listed at over seven feet. If he had played last season, however, he would have been one of 42. The bodies playing major professional sports have changed dramatically over the years, and managers have been more than willing to adjust team uniforms to fit the growing numbers of bigger, longer frames.

The trend in sports, though, may be obscuring an unrecognized reality: Americans have generally stopped growing. Though typically about two inches taller now than 140 years ago, today's people-especially those born to families who have lived in the U. S. for many generations-apparently reached their limit in the early 1960s. And they aren't likely to get any taller. "In the general population today, at this genetic, environmental level, we've pretty much gone as far as we can go," says anthropologist William Cameron Chum-lea of Wright State University. In the case of NBA players, their increase in height appears to result from the increasingly common practice of recruiting players from all over the world.

Growth, which rarely continues beyond the age of 20, demands calories and nutrients-notably, protein--to feed expanding tissues. At the start of the 20th century, under-nutrition and childhood infections got in the way. But as diet and health improved, children and adolescents have, on average, increased in height by about an inch and a half every 20 years, a pattern known as the secular trend in height. Yet according to the Centers for Disease Control and Prevention, average height--5 '9" for men, 5'4" for women--hasn't really changed since 1960.

Genetic maximums can change, but don't expect this to happen soon. Claire C. Gordon, senior anthropologist at the Army Research Center in Natick, Mass ensures that 90 percent of the uniforms and workstations fit recruits without alteration. She says that, unlike those for basketball, the length of military uniforms has not changed for some time. And if you need to predict human height in the near future to design a piece of equipment, Gordon says that by and large, "you could use today's data and feel fairly confident."

There are many colors in nature. But do you think that a color has weight? I think you'll say "no". But I'm afraid you are wrong. If you don't believe it, you may do a small experiment.

First, put two objects with the same weight into two boxes. Then cover the boxes. Third, wrap one box with a red piece of paper, the other one with white piece of paper. OK. Now hold the boxes with your hand one by one. It is certain that you will think the red one is a little heavier.

Why do you think so? A scientist found that different colors have different weights in man's mind. That is to say, every color has its own weight in our mind.

The scientist told us that colors also have smell. Can you smell the color? Of course not. Then why did the scientist say so? That is because every color stands for kind of light with a certain wavelength（波长）. It reaches our brain through sense organs.

According to this discovery scientists say that people accept the colors they like, and refuse the colors they hate. So your body and mind will be healthy by using the colors you like. Or you'll be nervous or even get ill. For example, you like blue and hate red. If you stay in a room with red windows, wallpaper and furniture for two hours, you'll feel you have been there for four hours. But if the room is blue, you'll feel you have been there for only an hour. And if a person walks out of a blue room and into a red room, his temperature will rise. That means our body temperature will change with different colors.