At the beginning of this century, medical scientists made an interesting discovery; we are built not just of flesh and blood but also of time. They were  (1)  to show that we all have “a body clock”  (2)  us, which controls the  (3)  and fall of our body energies,  (4)  us different from one day one to the next.

The   (5)  of “a body clock” should not be too  (6)  since the lives of most living things are controlled  (7)   the 24 hour night-and-day cycle. We feel  (8)  and fall asleep at night and become   (9)  and energetic during the day. If the 24 hour-cycle is  (10)  , most people experience unpleasant  (11)   . For example, people who are not  (12)   to working at night can find that  (13)   of sleep causes them to  (14)  badly at work.

  (15)   the daily cycle of sleeping and  (16)  , we also have other cycles which  (17)  longer than one day. Most of us would   (18)  that we feel good on some days and not so good on  (19)   ; sometimes our ideas seem to flow and at other times, they  (20)  ​do not exist.

Those who claim bananas are fattening argue that bananas cause the body to make lots of insulin(胰岛素), and insulin causes fat growth.

How much insulin we produce is related to how fast food becomes sugar in our bloodstream. How can you know if food makes a lot of sugar quickly? The glycemic index(血糖指数), or GI rating tells us.  Foods with GI scores above 75 are considered high-GI foods, leading to faster sugar development. Bananas have a GI of 62, which is considered low.

Weight loss can be a struggle for anyone, but it is especially hard for diabetics(糖尿病患者). A study looked at how the starch from unripe bananas affected the weight of a group of obese diabetics.  After four weeks of a diet high in bananas, diabetics lost significantly more weight than on a control diet. They also saw improvements in insulin sensitivity from the banana diet.

What’s more, bananas have been shown to cut risks of strokes, diabetes and cancers(Bananas are the most powerful fruit for lowering the risk of kidney cancer.). Bananas are also a rich source of fiber, which has been shown to help weight loss. Bananas that still have some green on the skin are even higher in fiber.

Skins from green bananas can be taken and, after removing the stem and dark tip, cut into small pieces 2－3 inches long and 1/2 inch wide. These pieces can be made into a tea or added to a dish. When you eat the skins, be sure you are eating organic bananas. The flesh of regular bananas is low in pesticides, but the skins are not.

     Now satellites are helping to forecast（预报）the weather. They are in space, and they can reach any part of the world. The satellites take pictures of the atmosphere（大气）, because this is where the weather forms（形成）. They send these pictures to the weather stations. So meteorologists（气象学家）can see the weather of any part of the world. From the pictures, the scientists can often say how the weather will change.

       Today, nearly five hundred weather stations in sixty countries receive satellite pictures. When they receive new pictures, the meteorologists compare（比较）them with earlier ones. Perhaps they may find that the clouds have changed during the last few hours. This may mean that the weather on the ground may soon change, too. In their next weather forecast, the meteorologists can say this.

         So the weather satellites are a great help to the meteorologists. Before satellites were invented, the scientists could forecast the weather for about 24 or 48 hours. Now they can make good forecasts for three or five days. Soon, perhaps, they may be able to forecast the weather for a week or more ahead（提前）.

Biologist Robert Pitman and his colleagues tracked orcas，or killer whales, and humpback whales off the coast of Western Australia. To research further, the scientists attached a tracker to a female orca, which allowed them to use satellites to monitor her movements. They followed her for six days. During that time, the orca attacked eight young humpback whales. During the seven attacks, the orca killed the humpback whale calf(幼兽) on three occasions.

But the story doesn’t end there. Humpback whales themselves are popularly thought to be large but generally, passive creatures. Pitman’s study findings may let people think otherwise.

When chased by orcas, humpback whales are known to try to outswim orcas. They are thought to do this at high speed so that the orcas can’t keep up. On some occasions, the humpback whales sought out protection. They swam to shallow water, nearby reefs, or even under the researchers’ boats. These ways often reduced the attack. But at other times, the humpback whales decided to stay and fight.

As the orcas approached, the mother humpback would sometimes move her calf to her side, or lift it out of the water using her head or flippers. She also blew huge breaths of air to disturb the orcas, and lunged or charged at them, slashing(劈) and slapping her tail and flippers. Perhaps most surprisingly, humpback whales also have adult escorts(护卫队) that try to protect calves that are not their own, joining the mother in defending the smaller whale. These escort whales either charged at the orcas, or placed themselves between the attackers and calves, slashing their tails and flippers.

Despite the efforts of the mother whales and escorts, the orcas were more often than not successful in their attacks. But the presence of the escorts did reduce how many times a whale calf was killed.

  Every now and then，a product comes along that proves itself a complete game－changer; as is the case with new British brand and invention，Eyejusters － the reading glasses that you can focus yourself － for less than ￡70！

      With 6 in 10 people wearing glasses in the UK，those with perfect vision are increasingly in the minority. And of those who do require glasses，many find themselves requiring two or three pairs of glasses in order to complete different tasks throughout the day. As well as being an added expense on top of everything else，this also means carrying around （and trying not to lose） those extra pairs！

      Evejusters allow you to instantly change the lens（镜片） strength of your glasses with hidden dials，tucked just inside the frames themselves. Eyejusters work by the wearer simply turning the concealed eyeDials to change the focus to fit your needs. The lenses adjust from ＋0.00 to ＋3.00 D，they also have anti－scratch technology and are lightweight in design so you aren't paying the price of comfort for convenience.

      The creator of Eyejusters，Owen Reading － who came up with the idea for Eyejusters with friend David Crosby，who studied physics at Oxford with him，explained: "Lots of people need reading glasses but they need glasses with lots of different strengths. They might have a pair with ＋l prescription－strength lenses for the computer，＋2s for reading and ＋3s for really close－up stuff. Eyejusters replace the need for multiple pairs of reading glasses，by covering the whole range from zero to ＋3，which is the strongest you will find in over－the－counter products."

      He added: "If you wear reading glasses，these are a much more flexible alternative. You can put them on and just turn the dial until what you want to see comes into focus. They are much like using binoculars（望远镜）."

Gray wolves once were seen here and there in the Yellowstone area and much of the continental United States, but they were gradually displaced by human development. By the 1920s, wolves had practically disappeared from the Yellowstone area. They went farther north into the deep forests of Canada, where there were fewer humans around.

The disappearance of the wolves had many unexpected results. Deer and elk populations—major food sources(来源) for the wolf—grew rapidly. These animals consumed large amounts of vegetation(植被), which reduced plant diversity in the park. In the absence of wolves, coyote populations also grew quickly. The coyotes killed a large percentage of the park’s red foxes, and completely drove away the park’s beavers.

As early as 1966, biologists asked the government to consider reintroducing wolves to Yellowstone Park. They hoped that wolves would be able to control the elk and coyote problems. Many farmers opposed the plan because they feared that wolves would kill their farm animals or pets.

The government spent nearly 30 years coming up with a plan to reintroduce the wolves. The U．S. Fish and Wildlife Service carefully monitors and manages the wolf packs in Yellowstone. Today, the debate continues over how well the gray wolf is fitting in at Yellowstone. Elk, deer, and coyote populations are down, while beavers and red foxes have made a comeback. The Yellowstone wolf project has been a valuable experiment to help biologists decide whether to reintroduce wolves to other parts of the country as well.

Most people are aware that outdoor air pollution can damage their health, but many do not know that indoor air pollution can also have significant health effects. Environmental Protection Agency studies indicate that indoor levels of pollutants(污染物) may be 2～5 times, and occasionally more than 100 times, higher than outdoor levels. These levels of indoor air pollutants may be of particular concern because most people spend about 90％ of their time indoors.

There are many sources of indoor air pollution in any home. These include combustion（燃烧）sources such as oil, gas, coal, wood, and tobacco products; building materials and furnishings such as wet or damp carpet, furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care or hobbies; central heating and cooling systems and humidification devices(加湿器); and outdoor sources such as pesticides（农药）, and outdoor air pollution.

Immediate effects may show up after a single exposure or repeated exposures. These include irritation of the eyes, nose, and throat, headaches, dizziness(晕眩), and fatigue(乏力). Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating(清除) the person’s exposure to the source of the pollution, if it can be identified. Symptoms(症状) of some diseases, including asthma, hypersensitivity, pneumonitis, and fever, may also show up soon after exposure to some indoor air pollutants.

The likelihood of immediate reactions to indoor air pollutants depends on several factors. Age and pre-existing medical conditions are two important influences. In other cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological pollutants after repeated exposures, and it appears that some people can become sensitized to chemical pollutants as well.

Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place the symptoms occur. If the symptoms fade or go away when a person is away from the home and return when the person returns, an effort should be made to identify indoor air sources that may be possible causes. Some effects may be made worse by an inadequate supply of outdoor air or from the heating, cooling, or humidity conditions prevalent in the home.

There are an extremely large number of ants worldwide.Each individual(个体的)ant hardly weighs anything,but put together they weigh roughly the same as all of mankind.They also live nearly everywhere,except on frozen mountain tops and around the poles.For animals their size,ants have been astonishingly successful,largely due to their wonderful social behavior.

In colonies(群体)that range in size from a few hundred to tens of millions,they organize their lives with a clear division of labor.Even more amazing is how they achieve this level of organization.Where we use sound and sight to communicate,ants depend primarily on pheromones(外激素),chemicals sent out by individuals and smelled or tasted by fellow members of their colony.When an ant finds food,it produces a pheromone that will lead others straight to where the food is.When an individual ant comes under attack or is dying,it sends out an alarm pheromone to warn the colony to prepare for a conflict as a defense unit.

In fact,when it comes to the art of war,ants have no equal.They are completely fearless and will readily take on a creature much larger than themselves,attacking in large groups and overcoming their target.Such is their devotion to the common good of the colony that not only soldier ants but also worker ants will sacrifice their lives to help defeat an enemy. 

Behaving in this selfless and devoted manner,these little creatures have survived on Earth for more than 140 million years,far longer than dinosaurs.Because they think as one,they have a collective(集体的)intelligence greater than you would expect from its individual parts.

Healthy Snacks for College Student

A busy schedule and a tight budget don’t mean you have to survive on junk food while in college.    36    You can bring them easily with you as you rush between classes. Focus your snack choices on simple ingredients that take only minutes to prepare.    37  

Sandwiches

Make a sandwich when you need something to eat. Use whole grain bread.   38    Slices of meat and low-fat cheese are also healthy choices. Include vegetables for both the nutrient and fiber. Lettuce, tomatoes and green peppers are just a few options.

Fruits and Vegetables

    Slice vegetables ahead of time and keep them in small plastic bags.    39    Celery, carrots and broccoli taste good. Include a small container of hummus（鹰嘴豆泥）in the bags if you don’t like to eat your vegetables plain. Both whole and sliced fruits are a healthy snack when you need something sweeter.

Warm Snacks

A warm snack is a welcome addition to a late-night study session. Warm a pita（口袋饼）round in the microwave for 20 to 30 seconds. Add any other vegetables that you like to the pita. Baked potatoes are another cheap and healthy option for snacking. For a sweeter snack, cut an apple in half and remove the core and seeds. Top with one teaspoon of brown sugar.    40    Let the apple cool for an additional five minutes before eating it.

A. If you want to pack apple slices, use a teaspoon of lemon juice.

B. Top the pita with cream cheese and tomato slices.

C. Fill the sandwich with peanut butter.

D. Warm it in the microwave for five minutes.

E. Thus snack preparation doesn’t cut into the time you need for study.

F. Many healthy snacks are low-cost and what’s more, they’re portable（便携的）

G. This ensure that you can grab them quickly when hunger strikes.

G

The days of having to carry a phone charger everywhere could soon be over.Michigan researchers have revealed a major breakthrough in harvesting energy from human motion. They say it could lead to smartphones powered for a week by the motion of a swipe(重击).

   Michigan State University’s low-cost device, known as a nanogenerator, has already been tested.Scientists successfully operated an LCD touch screen, a bank of 20 LED lights and a flexible keyboard, all with a simple touching or pressing motion and without the aid of a battery. The groundbreaking findings, published in the journal Nano Energy, suggest “We’re on the path toward wearable devices powered by human motion,” said Nelson Sepulveda, associate professor of electrical and computer engineering and lead researcher of the project.

“What I foresee, relatively soon, is the capability of not having to charge your cell phone for an entire week, for example, because that energy will be produced by your movement,” said Sepulveda, whose research is funded by the National Science Foundation.

   Electrical energy is created when the device is compressed by human motion. The completed device is as thin as a sheet of paper. The device used to power the LED lights was palm-sized, while the device used to power the touch screen was as small as a finger. Advantages such as being lightweight, flexible and low-cost could make it a promising and alternative method in the field of Mechanical-energy harvesting.

   The device also becomes more powerful when folded. Sepulveda said, “You can start with a large device, but when you fold it once, and again, and again, it’s much smaller and has more energy. Now it may be small enough to put in a specially made heel of your shoe so it creates power each time your heel strikes the ground.”

   Sepulveda and his team are also developing technology that would transmit the power generated by the heel strike to, say, a wireless headset.