VOA Sccience in Technology

1. Daily Exercise Leads to Better Health

From VOA Learning English, this is Science in the News. I'm Bob Doughty. And I'm June Simms. Today, we will tell why exercise is so important. And we will tell about some popular ways to get in good shape.

Health experts have long noted the importance of physical activity. Exercise not only improves your appearance. It can also improve your health. Exercise helps to reduce the risk of some diseases. They include heart disease, stroke, type-two diabetes, osteoporosis and even some kinds of cancer.

America's Centers for Disease Control and Prevention says heart disease is the leading cause of death in the United States. About 600,000 Americans die of heart disease every year. High blood pressure and high cholesterol levels in blood can increase your risk of heart disease. Medical experts say both can be reduced through normal exercise.

Physical activity is also known to increase the release of endorphins. These chemicals reduce feelings of pain. They also help people feel more happy and peaceful. There is some debate about exactly what causes the brain to release endorphins. Some experts believe it is the act of exercising itself. Others say it is the feeling one gets from having met an exercise goal. Either way, the two things work together when it comes to improving one's emotional health.

Exercise improves your energy levels by increasing the flow of blood to the heart and blood vessels. One of the main reasons people exercise is to control or reduce their weight. Physical activity burns calories – the energy stored in food. The more calories you burn, the easier it is to control or reduce your weight.

So exactly how much exercise do you need to do to gain all of these great health effects? Experts say it is easier than you think. In 2008, the Centers for Disease Control released its first ever Physical Activity Guidelines for Americans. The report included suggestions for young people, adults, disabled persons and those with long-term health problems.

One of the major ideas noted in the report was that some activity is better than none. So if you are not doing anything, now is the time to get started. CDC officials define physical activity as anything that gets your body moving. And, it says there are two separate, but equally important kinds of physical activity.

Aerobic or cardio exercise gets your heart rate going faster and increases your breathing. Some examples are activities like walking at an increased speed, dancing, swimming or riding a bicycle. Muscle-strengthening activities help build and strengthen muscle groups in the body. This kind of exercise includes lifting weights, or doing sit-ups and push-ups.

To get the most from your exercise plan, experts say adults should get at least two and a half hours of aerobic exercise each week. More intense activities reduce the suggested amount of time to one hour and 15 minutes. Some examples are playing basketball, swimming and distance running.

Earlier advice from the CDC said that people need to exercise at least 30 minutes each day for at least five days to get the health benefits of exercise. More recent research has suggested that those gains are the same whether you exercise for short periods over five days or longer sessions over two or three days.

In addition, the newer suggestions say any exercise plan should include at least two days of muscle training. Each

exercise period should be at least 10 minutes long. The total amount of activity should be spread over at least two days throughout the week. Most importantly, experts say people should choose physical activities that they find fun. This helps to guarantee that they stay with the program.

So, what are some of the most popular forms of exercise in the United States? Walking tops the list. A 2012 report from the CDC found that more than 145 million Americans now include walking to stay physically fit. For many people, it is considered the easiest way to get exercise. It does not require a health club membership.

Walking is safe. And, it is said to be as valuable for one's health as more intense forms of exercise like jogging. Walking is also said to be less damaging to the knees and feet. This makes it a better choice of exercise for older adults. Another popular form of exercise is jogging, or running at a slow to medium speed.

USA Track and Field Hall of Famer Bill Bowerman was credited with bringing jogging to the United States in the 1970s. He did so after witnessing the popularity of the activity himself during a trip to New Zealand in the 1960s. He started the first running club in America and wrote a book about jogging for fitness. Bill Bowerman also helped establish Nike, the tennis shoe company.

Jogging provides great physical conditioning for the heart and lungs. And, it increases the flow of blood and oxygen in the body. All of these things combined help to improve heart activity, lower blood pressure and cholesterol levels, and reduce bone and muscle loss. Running is also a good way to lose weight. People burn an average of 160 calories a kilometer while running.

The Census Bureau says swimming was the fourth most popular sports activity in the United States in 2009. The top activity was exercise walking, followed by exercising with equipment and camping. Swimming is said to be one of the best ways to exercise. Nearly all of the major muscle groups are put to work.

Swimming also presents less risk of muscle and joint injury because of the body's weightlessness in water. This makes it a great choice of exercise for people with special needs, like pregnant women, older adults, and persons who are overweight. Some people have questioned whether swimming burns as many calories as other forms of exercise. But one thing is sure: the effects on your health are just as great. Water aerobics is another popular form of exercise. This can be anything from walking or running against the resistance of water, to doing jumping jacks in the water.

Dancing can also be a fun way to exercise. This is especially true for those who see exercise as a necessary evil: something they should do, not something they want to do. A dance-fitness program called Zumba has grown in popularity in recent years. Zumba is said to be one of the fastest-growing group programs in the physical fitness industry today. Alberto Beto Perez created Zumba in his native Colombia in the 1990s. His dance-fitness program is based on salsa, meringue, and other forms of Latin American music.

Mister Perez brought the program to the United States in 2001. Since then it has spread around the world. The Zumba website says its classes are now offered in 140,000 gyms, fitness studios and dance clubs around the world. That is up from about 2,000 locations in 2006. The website also says that 14 million people now attend Zumba classes in 151 countries.

Whatever kind of exercise you choose, experts agree that you should start small and work your way up. Start by exercising 10 minutes a day two times a week. After a few weeks, increase your time to 15 or 20 minutes, and increase the number of days. Next, aim to increase the intensity of your workout. If you have been walking, trying walking faster, or take turns between walking and jogging. And try not to forget those muscle strengthening exercises.

The more time you spend exercising, the more health benefits you get. Health experts advise people who have been physically inactive to have a complete physical exam before beginning a new exercise program. If one of the goals of your exercise program is to lose weight, you will also need to change how and what you eat. Next week we will look at the influence of diet on your weight loss efforts.

This Science in the News was written and produced by June Simms. I'm Bob Doughty. And I'm June Simms. Join us next week for more news about science on the Voice of America.

2. Science in the News – Aspirin

From VOA Learning English, this is Science in the News. I'm Mario Ritter.

And I'm Avi Arditti. Today, we tell the story of aspirin.

People have known since ancient times that aspirin helps to reduce pain and high body temperature. But that is not all aspirin can do. It has gained important new uses in recent years. Small amounts of the drug may help prevent a heart attack or stroke.

One study showed that some people who took two aspirin pills a day had lower rates of colorectal cancer.

And researchers say aspirin may help patients with colon cancer live longer. But others say the acid in aspirin can cause bleeding in the stomach and intestines. And studies showed that aspirin or other pain medicines may lead to loss of eyesight and hearing.

So, how did aspirin become so important? The story begins with a willow tree. Two thousand years ago, the Greek doctor Hippocrates advised his patients to chew on the bark and leaves of the willow. The tree contains the chemical salicin. In the 1800s, researchers discovered how to make salicylic acid from salicin.

In 1897, a chemist named Felix Hoffmann at Friedrich Bayer and Company in Germany created acetyl salicylic acid. Later, it became the active substance in a medicine that Bayer called aspirin.

In 1982, a British scientist shared the Nobel Prize in Medicine in part for discovering how aspirin works. Sir John Vane found that aspirin blocks the body from making natural substances called prostaglandins.

Prostaglandins have several effects on the body. Some cause pain and the expansion, or swelling, of damaged tissue. Others protect the lining of the stomach and small intestine. Prostaglandins make the heart, kidneys and blood vessels work well.

But there is a problem. Aspirin works against all prostaglandins, good and bad. Scientists have also learned how aspirin interferes with an enzyme. One form of this enzyme makes the prostaglandin that causes pain and swelling. Another form creates a protective effect. So aspirin can reduce pain and swelling in damaged tissues. But it can also harm the inside of the stomach and small intestine. And sometimes it can cause bleeding.

Many people take aspirin to reduce the risk of a heart attack or stroke from blood clots. Clots can block the flow of blood to the heart or brain and cause a heart attack or stroke. Scientists say aspirin prevents blood cells called platelets from sticking together to form clots.

A California doctor named Lawrence Craven first reported this effect in the 1950s. He observed unusual bleeding in children who chewed on an aspirin product to ease the pain after a common operation. Doctor Craven believed the bleeding took place because aspirin prevented blood from thickening. He thought this effect might help prevent heart attacks caused by blood clots. He examined the medical records of 8,000 aspirin users and found no heart attacks in this group. He invited other scientists to test his ideas. But it was years before large studies took place.

Charles Hennekens of Harvard Medical School led one of the studies. In 1983, he began to study more than 22,000 healthy male doctors over 40 years of age. Half took an aspirin every other day. The others took what they thought was aspirin. But it was only a placebo, an inactive substance. Five years later, Dr. Hennekens reported that people who took aspirin reduced their risk of a heart attack. But they had a higher risk of bleeding in the brain than the other doctors.

A few years ago, a group of experts examined studies of aspirin at the request of federal health officials in the United States. The experts said people with an increased risk of a heart attack should take a low-strength aspirin every day. Aspirin may help someone who is having a heart attack caused by a blockage in a blood vessel. Aspirin thins the blood, so the blood may be able to flow past the blockage. But experts say people should seek emergency help immediately. And they say an aspirin is no substitute for treatment, only a temporary help.

But what about reducing pain? Aspirin competes with other medicines for reducing pain and high body temperature. The competition includes acetaminophen, the active substance in products like Tylenol. It also includes ibuprofen, the active substance in products such as Advil. Like ibuprofen, aspirin is an NSAID -- a non-steroidal anti-inflammatory drug.

Several studies have found that men who take aspirin or other NSAIDS have a decreased risk of prostate cancer. The prostate is a gland and part of the male reproductive system. Researchers at the Mayo Clinic in Minnesota wanted to see how NSAIDs might affect prostates that are enlarged, but not cancerous. They followed the health of 2,500 men for 12 years. The researchers said these drugs may delay or stop development of an enlarged prostate. They said the risk of an enlarged prostate was 50 percent lower in the NSAID users than the other men. The risk of bladder problems was 35 percent lower.

Other studies have suggested that aspirin can help with cancer prevention and survival. They showed that aspirin may help prevent cancers of the stomach, intestines and colon. In 2008, European researchers reported that aspirin may have what they called a "long-term protective effect against colorectal cancer." Peter Rothwell of the University of Oxford led the researchers. They found that people who took one aspirin a day for about six years reduced their risk of colon cancer by 24 percent. And, deaths from the disease dropped by 35 percent.

In 2010, the Lancet published the combined results of a larger observational study, also led by Professor Rothwell. This time, he and other researchers found that taking a small aspirin once a day reduced death rates from a number of common cancers.

Aspirin does not help everything, however. It can cause problems, like an increased danger of stomach bleeding and ulcers. And it can interfere with other medicines. Also, some people should not take aspirin. These include people who take other blood thinners or have bleeding disorders. Pregnant women are usually also told to avoid aspirin.

Research has shown a link between aspirin use and a condition called Reye's syndrome. Children's doctors say patients up to age 19 should not take anything containing salicylatic products when sick with high temperatures. Recently, American researchers reported finding a small link between aspirin use and one kind of blindness. Age-related macular degeneration, or AMD, affects older adults. It limits their ability to see objects directly in front of them.

Barbara Klein of the University of Wisconsin led the study. She and her team found that people who regularly took aspirin for 10 years or more had a small increase in the risk of advanced or "late" AMD. "Regularly" meant at least twice a week for more than three months. In a separate study, Australian researchers found that people who take aspirin regularly for many years are more likely to develop neovascular AMD.

This study involved nearly 2,400 adults. Almost 11 percent of them identified themselves as regular aspirin users. Eye tests were performed after five, 10 and 15 years. The researchers found that aspirin takers had twice the risk of neovascular, or "wet," AMD in comparison to non-regular aspirin users. The findings were reported in December 2012 in the Journal of the American Medical Association.

American researchers found a link between hearing loss in women and their use of ibuprofen or acetaminophen. The researchers studied information about more than 62,000 women between 31 and 48 years of age. The researchers examined how often the women reported using aspirin, ibuprofen or acetaminophen. The information covered the period from 1995 to 2009. Just over 10,000 women reported some hearing loss.

The study was the work of researchers at Brigham and Women's Hospital in Massachusetts. Lead researcher Sharon Curhan noted that NSAIDS may reduce blood flow to the cochlea, the hearing organ, and affect its ability. She noted that while such medicines can be purchased without a doctor's order, they still carry possible side effects.

Experts say most people should not take aspirin for disease prevention without first talking to a doctor because there are risks. Some researchers have even said that some people get little or no protection from aspirin. So research continues on one of the oldest and most widely used drugs in the world.

3. Have a headache? You are not alone

From VOA Learning English, this is Science in the News. I'm Steve Ember. Today Barbara Klein and I tell about headaches, the pain that strikes almost everyone at some time.

Have you had a headache recently? If your answer is yes, you are like many millions of people worldwide who experience pain in the head. The pain can be temporary, mild and cured by a simple painkiller like aspirin. Or, it can be severe.

The National Headache Foundation says more than 45 million people in the United States suffer chronic headaches. Such a headache causes severe pain that goes away but returns later.

Some headaches may prove difficult and require time to treat. But many experts today are working toward cures or major help for chronic headaches.

The U.S. Headache Consortium is a group with seven member organizations. They are working to improve treatment of one kind of headache -- the migraine. Some people experience this kind of pain as often as two weeks every month. The National Headache Foundation says about 70 percent of migraine sufferers are women.

Some people describe the pain as throbbing, causing pressure in the head. Others compare it to someone driving a sharp object into the head. Migraine headaches cause Americans to miss at least 150 million workdays each year. A migraine can be mild. But it also can be so severe that a person cannot live a normal life.

One migraine sufferer is Curtis Croley of Ellicott City in Maryland. He had head pain as a child. Mr. Croley says he does not know what kind of headaches they were. But when he suffered severe headaches as an adult, doctors identified the problem as migraine.

Today, Mr. Croley produces and directs films and videos. He says months can pass without a headache. But then he will have three migraines within a month. If he takes the medicine his doctor ordered early in his headache, it controls the pain in his head. If not, the pain becomes extremely bad. Sometimes he has had to be treated with a combination of drugs in a hospital.

Some people take medicine every day to prevent or ease migraine headaches. Others use medicine to control pain already developed. Doctors treating migraine sufferers often order medicines from a group of drugs known as triptans.

Most migraines react at least partly to existing medicine. And most people can use existing medicine without experiencing bad effects. Doctors sometimes use caffeine to treat migraine headaches. Interestingly, caffeine can also cause some migraines.

Medical experts have long recognized the work of the Mayo Clinic in Rochester, Minnesota. The Mayo Clinic says several foods are suspected of being "triggers" that start migraines. They include cheese and alcoholic drinks. Food additives like salt and monosodium glutamate also may be triggers.

The Mayo Clinic tells patients to avoid strong smells that have seemingly started migraines in the past. Some people react badly to products like perfume, even if they have a pleasant smell.

The clinic's experts say aerobic exercise can help migraine sufferers. Aerobic exercise increases a person's heart rate. It can include walking, swimming or riding a bicycle. But a sudden start to hard exercise can cause headaches. So it is a good idea to perform some mild exercises before beginning activities that require more energy.

The experts advise that people should plan to exercise, eat and sleep at the same times each day.

The Mayo Clinic also has advice for women who suffer from migraines. The female body makes estrogen. Drugs like birth control pills contain a version of this chemical. Such drugs may produce headaches or cause them to worsen, the clinic warns. But they can also cause an easing of headache pain. The same is true for estrogen replacement drugs for women. Doctors sometimes order estrogen replacement for women who are no longer able to have children.

The Mayo Clinic says there are alternative, or nontraditional, ways to treat migraine. Among them is acupuncture, in which thin needles are placed below the skin at defined areas.

The clinic says another method, biofeedback, is especially effective for migraine. In biofeedback, patients use special equipment to learn how to observe and control physical reactions linked to stress. Some people get help from massage, systematic rubbing of the body. Others use herbs, minerals or vitamins.

More people suffer tension headaches than migraines. But most tension headaches are not as powerful. Events that start tension headaches may include emotional pressure and the deeper than normal sadness called depression. Other tension headaches can start from something as simple as feeling tired. Common changes in atmospheric conditions also can be responsible.

The Mayo Clinic says you may feel a tension headache as tightness in the skin around your eyes. Or, you may feel pressure around your head. Episodic tension headaches strike from time to time. Chronic tension headaches happen more often. A tension headache can last from a half hour to a whole week.

The Mayo Clinic says the pain may come very early in the day. Other signs can include pain in the neck or the lower part of the head. Scientists are not sure what causes tension headaches. For years, researchers blamed muscle tension from tightening in the face, neck and the skin on top of the head. They believed emotional tension caused these movements. But that belief has been disputed.

The International Headache Society began organizing a system for identifying differing forms of headaches in 1985. The society says there is no evidence that tense muscles are the only cause of pain. So it suggests that tension headaches be called tension-type headaches.

Some scientists now believe that tension headaches may result from changes among brain chemicals such as serotonin. These changes may start sending pain messages to the brain. The changes may interfere with brain activity that suppresses pain.

Whatever the cause of the headache, people do not enjoy the experience. Treatment can be as simple as aspirin or other painkillers. But if your pain is too severe, you will need a doctor's advice.

A website called https://www.wendangku.net/doc/e010468653.html, provides information from the American Academy of Family Physicians. It offers suggestions to ease or end a tension headache.

For example, it says putting heat or ice on your head or neck can help. So can standing under hot water while you are getting washed in the shower. The group also advises exercising often. Another idea is taking a holiday from work. But you had better ask your employer first.

Ask anyone with a cluster headache, and they will tell you that the pain is terrible. The Cleveland Clinic in Ohio says the cluster headache can be many times more intense than a migraine.

Cluster headaches usually strike young people. Smokers and people who drink alcohol often get such headaches. Men are about six times more likely than women to have them. The Cleveland Clinic says this is especially true of younger men. Doctors say cluster headaches often strike during changes of season.

Cluster headache patients describe the pain as burning. The pain is almost always felt on one side of the face. It can last for up to 90 minutes. Then it stops. But it often starts again later the same day. Eighty to 90 percent of cluster headache patients have pain over a number of days to a whole year. Pain-free periods separate these periods.

The Cleveland Clinic says the cause of cluster headaches is in a brain area known as a trigeminal-autonomic reflex pathway. When the nerve is made active, it starts pain linked to cluster headaches. The nerve starts a process that makes one eye watery and red.

Studies have shown that activation of the trigeminal nerve may come from a part of the brain called the hypothalamus. The Cleveland Clinic says injections of the drug sumatriptan can help. Many other drugs could be used. For example, doctors say breathing oxygen also can help.

Thankfully, modern medicine has ways to treat almost all of our headaches.

4. Farmer Invents New Way to Grow Crops

From VOA Learning English, this is Science in the News. Today, we tell about an American farmer and an unusual device he developed. For 20 years, people around the world have been buying his invention.

Blake Whisenant and his family are farmers. They live in the American state of Florida. For nearly 100 years, Mr. Whisenant's family has grown fruits and vegetables, and sold them to businesses around the world. The warm weather in central Florida is good for growing crops, especially tomatoes. That is what he grows the most of on his eight hundred hectares of land. In 1992, Mister Whisenant had some bad luck.

It began to rain. And...it rained. And it rained some more. Nearly 50 centimeters of rain destroyed the tomato crop that year. Blake Whisenant was not a happy farmer.

"I just thought there's got to be a better way!"

So, he began looking to find a way to make sure this never happened again. He wanted to develop a system

that would provide water to the plants from below. He thought some kind of cover would keep rain away and the soil warm. He wanted the plants to be grown in a box that would take up little space. He became obsessed with the idea and thought about it day and night.

"And I told my wife, before I die I wanted to see if I could build me a box above the ground that I could grow tomatoes in."

And...after years of work...he knew what to do. He found a company in Pennsylvania that agreed to make the box. It would be made of thick plastic, and would be about one meter long and half a meter deep. Inside the box would be a plastic tube to pour the water in, and a plastic screen with many holes in it. Something like peat moss, but not soil, would be placed in the box on top of the screen, which would hold it above the water in the bottom of the box. A thin plastic cover would fit over the top of the box to keep out rain and harmful insects. Blake called it...the EarthBox.

The Story of Container Gardening

Frank DiPaolo is the general manager of the EarthBox Company in Scranton, Pennsylvania. He says that growing vegetables this way...container gardening some call it...makes it easy for Blake Whisenant and other farmers to quickly solve common growing problems.

"When he saw any sort of disease or problems with the plants in the field, one human being could basically go and grab the box and just pull that problem right out of the field before it spread to the other plants."

Frank DiPaolo says normal dirt or soil will not work in this kind of container gardening. Instead, potting mix is used. This is mostly peat moss with a few things added to help air get to the roots of the plants.

"One of its responsibilities is to wick the water up to the plants. When you put a small seedling in, the roots are not deep enough to go into that water reservoir, so we need to bring the water up to the plant."

The box holds about 11 liters of water. There is a small hole in the side to drain out extra moisture and keep from drowning the plants. Since the potting mix soaks up the water, you have to pour more water down the tube every day or so. This kind of container gardening uses much less water than is needed when growing plants in the ground. And it is made so you can never give too much or too little water to the plants.

The plants in the box also need two other things...a small amount of fertilizer and dolomite, a powder-like substance made from limestone. The fertilizer feeds the plants and helps them grow. The dolomite helps to reduce acid in the potting mix. Many farmers say dolomite is the secret to growing good tasting tomatoes. Dolomite is also a low-cost way to supply calcium to young tomato plants. This helps to protect the plants from a disease known as "blossom end rot."

"That's where your tomato plant will start setting fruit ...and they look beautiful and you come back a couple of days later and they've grown to a pretty nice size...and the bottom of the tomato is all black. And they call that blossom end rot."

Before the plants are put in the EarthBox, there is one more thing that must be done. A thin plastic cover is stretched over the top of the box. If storms should bring large amounts of rain, the cover protects the potting mix, fertilizer, and dolomite inside the box. This cover also keeps weeds and harmful insects out of the box. But there is one other reason that the container must be covered. It is important that the potting mix be kept warm, but not too hot. Frank DiPaolo says you should use either a white or a black cover.

"The covers that we ship with the box are black on one side and white on the other. If you live where we live in northeastern Pennsylvania and you want to drive as much heat as you can into the container, we plant the plants with the black side up. Say, if you were in Florida where Blake lives, in the summer he'll plant with the white side up. You get about a 15 degree Fahrenheit change in the soil temperature just by using the white side versus the black side."

There also has been some research done using other colors for the box covers. One study found that a red cover produces better results for vegetables like tomatoes and red peppers.

Frank DiPaolo says that, if you prepare the box correctly, nature will do the rest.

"The plants know what they need from a nutritional and a water sense. So if you put the materials within reach of the plant, the plant will take what it needs when it needs it."

So after preparing the box, how many tomato plants do you use? The answer is ...only two! And why is that?

"The reason is that those plants are going to get so big that if you were to put three or four or six plants in, they are just going to be crowding each other out, and each plant is going to underperform."

Putting the plants in the box is easy. Blake Whisenant uses a sharp knife to cut a small round hole in the cover. He then uses his hand to take out a small amount of potting mix. He sets the plant into the hole, presses the roots down a bit, and then puts back the handful of potting mix.

Many people who have used EarthBoxes say it is possible to get over 22 kilograms of tomatoes, from just two plants.

Environmental and Other Effects

Growing crops in containers is good for the environment. In addition to using less water, little fertilizer is needed, and it all stays in the box. There is no way the chemicals can run off into nearby waterways. The same potting mix can be used for five or six years. In countries where potting mix is not available or too costly, growers can use coconut coir instead. This comes from the outside shell of the coconut and it is low in cost.

Coconut coir is also a renewable resource. Each new coconut that grows will provide some coir. The peat moss that is used in many potting mixes, however, can take thousands of years to grow. Gardeners can use

up peat moss much faster than it can be replaced by nature.

Since the EarthBox went on sale in 1994, many people around the world have used them. Other people have made their own vegetable growing boxes. Some use two large plastic containers to make what is known as a "Global Bucket." One bucket has holes in the bottom and sits inside the other bucket. Potting mix or coir goes into the top bucket, and water goes through a tube into the bottom bucket. A plastic trash bag is then used to cover the top container.

Many kinds of fruits and vegetables can be grown in containers like these. Some people think this kind of gardening will be important for people in poor countries where hunger is a problem. A lot of food can be grown in a small space for a small amount of money.

Using Earthbox to Educate Children

The people who make EarthBoxes are interested in educating young people. They have developed a program aimed at teaching science and agriculture to students from their prekindergarten years through high school. Using an EarthBox in the classroom, the youngest child learns about seeds, the parts of plants, how gravity affects plants, and the uses of sunflowers.

When children first enter elementary school, they learn about water, soil, light, and nutrition. In middle school, they do experiments and collect information. In high school, the students learn how to use mathematics and graphs to better understand what happens when plants grow. The learning program includes written materials for the teachers and students. And it uses an EarthBox in the classroom as a small laboratory for experiments.

Molly Philbin is the Education and Community Garden director for the EarthBox Company.

"Kids really get engaged in science in the garden where it's a kind of fun activity where they're collecting data and seeing how different temperatures will change the amount of water that's needed by a crop, so the science concepts come easily."

Ms. Philbin also says that growing food locally in a container helps lower pollution from burning fossil fuels like oil. Often food travels thousands of kilometers from the farm before it reaches the table at home. A lot of fuel is needed just to deliver the food. Farmers who use growing boxes do not have to plow the land before they plant crops. That saves on the cost of fuel and on the pollution from farm machinery.

The man who started it all, Blake Whisenant, still lives near his farm in Florida. Health problems and age...he is over 80...now keep him from working in the fields. But he still goes to the EarthBox store nearly every day and enjoys teaching classes about agriculture to visitors. He says he likes the idea of passing along his knowledge to the next generation. Helping to educate the children, Blake says, has been a blessing.

This Science in the News was written, read and produced by Jim Tedder. Join us again next week for more news about science on the Voice of America. I'm Christopher Cruise.

5. Breathing Easier: How to Control Asthma

And I'm Bob Doughty. Spring has returned to the United States. The sky is blue, the grass is green and many plants are flowering. Spring can be a beautiful time of year. But it is especially troublesome for people with asthma. High pollen levels can keep asthma sufferers from enjoying spring flowers and the weather.

Asthma Awareness Month

May is "Asthma Awareness Month" in the United States. And May first is "World Asthma Day." The Global Initiative for Asthma, or GINA, organizes the event every year. GINA is a joint effort of the World Health Organization and the National Heart, Lung and Blood Institute of America's National Institutes of Health.

GINA held its first "World Asthma Day" in 1998. This year, the theme for "World Asthma Day" is "You Can Control Your Asthma." GINA first launched this education campaign as part of the event in 2007. The group notes that while asthma cannot be cured, it can be successfully controlled.

Asthma is a disorder that causes breathing passages to narrow. This reduces the amount of air entering and leaving the lungs, causing difficulty in breathing.

The World Health Organization says asthma affects about 235 million people worldwide. The WHO says asthma is the most common chronic disease among children. And it says the disease affects people in all countries around the world and at every development level. However, the WHO says 80 percent of asthma deaths happen in low and lower middle income countries.

Asthma affects not only millions of individuals, but families and economies alike. The yearly economic cost of the disorder is said to be close to 20 billion dollars. And, the World Health Organization warns that asthma rates are increasing worldwide by an average of 50 percent every 10 years.

Asthma Attacks

Asthma happens when tissue that lines the airways to the lungs begins to expand or swell. This swelling makes the airways smaller. The muscles in the airways tighten. Cells in the airways begin to produce a lot of mucous. This thick, sticky substance can cause the airways to close even more. This makes it difficult for air to flow in and out of the lungs.

This series of events is called an asthma attack. As asthma sufferers struggle to get air into their lungs, they may begin to cough. They also may experience wheezing -- breathing hard with a breathy, whistling sound.

Some asthma sufferers have tightness or pain in the chest. They say it feels as if someone is sitting on them. When asthma is most severe, the person may have extreme difficulty breathing. The disorder can severely limit a person's activity, and even lead to death.

Doctors do not know what causes asthma. Medical researchers believe a combination of environmental and

genetic conditions may be responsible. Forty percent of children who have parents with asthma will also develop this disorder. Seventy percent of people with asthma also have allergies. Allergies are unusual reactions of the body's natural defenses to normally harmless substances or conditions.

Doctors have identified many of the things that may trigger, or start, an asthma attack. Triggers are things that cause an asthma sufferer's airways to swell, or increase in size.

Different asthma patients have different triggers. Allergens are one of the most common triggers. These impurities in the air cause allergic reactions. Some of the more common allergens include animal hair, dust, mold and pollen.

Pollen is a fine dust that comes from grass, trees and flowers. Mold is a kind of fungus. It can grow on the walls or floors of homes. It is often in wet or damp areas like bathrooms, kitchens and basements.

The Environmental Protection Agency estimates that 21 percent of asthma cases in the United States have links to mold and dampness in homes.

Air pollution can also trigger asthma. Cigarette smoke is a major problem for asthma sufferers. So is air pollution from motor vehicles. Chemical sprays like air fresheners, hair spray, cleaning products and even strong beauty aids can trigger an asthma attack.

Some people cough, wheeze or feel out of breath during or after exercise. They are said to suffer from exercise-induced asthma. During the winter, breathing in cold air can trigger an asthma attack. So can colds and other infections of the respiratory system.

The Centers for Disease Control and Prevention says more than 25 million people in the United States have asthma. It says the disorder affects more than 7 million American children. Among adults, more women have the disease than men. However, it is more common among boys than girls.

The National Institute of Allergy and Infectious Diseases says the disease affects African-Americans more than whites. African-American children die from asthma at five times the rate of white children.

True Story of an Asthma Patient

VOA broadcaster June Simms has a son with asthma. Arick Simms first showed signs of the disease when he was about two years old.

Arick's doctor gave him a medicine called albuterol. Albuterol helps to increase air flow and reduce tension in the airways. The doctor also gave him a machine called a nebulizer. It connects to a mask that fits over the nose and mouth.

The nebulizer turns the liquid albuterol into a fog-like mist. Arick inhaled the mist through the mask. The treatments made it easier for him to breathe. During times when Arick's asthma was really severe, he was also given steroid medicines to help reduce swelling in his airways.

As Arick grew older, the doctor replaced his nebulizer with an inhaler. The small medical devices helped him to breathe easier. He also began seeing a doctor who specializes in treating patients with asthma.

The doctor discovered that Arick also suffers from allergies. He now takes medicines every day to help keep his asthma and allergies under control.

Advice For Controlling Asthma

The Global Initiative for Asthma was formed in 1993. GINA works with health care experts and public health officials around the world to improve asthma care and to reduce the number of asthma cases.

In 2004, GINA released a report called "The Global Burden of Asthma." The group said asthma is a growing problem in both industrial and developing countries. It estimated that there may be an additional 100 million people with asthma by the year 2025.

GINA says there are many things that people can do to control their asthma.

People should know the causes of their asthma symptoms and try to avoid these triggers. For example, seek to avoid animal hair, dust, pollen and cigarette smoke. Some people may need to take medicines before they work hard or exercise.

Asthma patients should work with their doctors to control the disorder. They should go to the doctor for medical examinations even if they are feeling fine. They should make sure they understand how and when to take their medicines. They also should act quickly to treat asthma attacks and know when to seek medical help.

The Global Initiative for Asthma urges governments and health officials to do more to improve asthma control. GINA hopes to reduce asthma hospitalization by 50 percent by the year 2015.

This Science in the News was written by June Simms, who was also our producer. I'm Bob Doughty.

6Scientific and Engineering Skills Lead to Inventions that Save Lives

This is Science in the News, in VOA Special English. I'm June Simms. Today Shirley Griffith and Bob Doughty tell about two recent inventions that have helped to save lives. We will also tell about the people who developed them.

History of Seat Belts

Most cars have seat belts as part of their equipment. Seat belts protect drivers and passengers in case of accident. They also reduce the effect of a crash on the body. Safety experts estimate that the restraining devices save thousands of lives a year in the United States alone. Worldwide, some experts, say the devices have protected up to a million people.

The first seat belt was said to have been created in the 1800s by George Cayley of England. He is

remembered for many inventions, especially for early "flying machines."

The United States first recognized the invention of an automobile seat belt in 1849. The government gave a patent to Edward J. Claghorn of New York City so that others would not copy his invention. Claghorn called the device a Safety-Belt. It was said to include hooks and other attachments for securing the person to a fixed object.

Modern Seat Belt Developed in Swede n

Other inventors followed with different versions of the seat belt. But more than 100 years passed before the current, widely used seat belt was developed. It resulted from the work of a Swedish engineer, Nils Bohlin. His three-point, lap and shoulder seat belt first appeared on cars in Europe 50 years ago.

Bohlin was born in Sweden in 1920. After completing college, he designed seats for the Swedish aircraft industry. The seats were built for the pilot to escape from an airplane in case of disaster. Bohlin's work with planes showed him what could happen in a crash at high speed. In 1958, Bohlin brought that knowledge to the Swedish car manufacturer Volvo. He was the company's first chief safety engineer.

At the time, most safety belts in cars crossed the body over the abdomen. A buckle held the restraints in place. But the position of the buckle often caused severe injuries in bad crashes.

Nils Bohlin recognized that both the upper and lower body needed to be held securely in place. His invention contained a cloth strap that was placed across the chest and another strap across the hips. The design joined the straps next to the hip.

Volvo was the first automobile manufacturer to offer the modern seat belt as a permanent addition to its cars. It also provided use of Nils Bohlin's design to other car-makers.

The Swedish engineer won many honors for his seat belt. He received a gold medal from the Royal Swedish Academy of Engineering Sciences in 1995. He died in Sweden in 2002.

American Stephanie Kwolek Invents Kevlar

Kevlar is another invention that has saved many people from serious injury and death. Kevlar is a fibrous material with qualities that make it able to reject bullets. Added to clothing, the material protects security officers and soldiers across the world.

The fibers form a protective barrier against gunfire. Bullets lose their shape when they strike Kevlar. Those bullets look like mushrooms, and do not enter the body. Most threats to police and security officers come from handguns. They wear Kevlar vests to protect the upper body. Soldiers wear more extensive clothing protected with Kevlar against heavier ammunition.

Kevlar might not have been invented had Stephanie Kwolek been able to seek a career in medicine. From childhood, she wanted to be a doctor. But she lacked the money for a medical education.

Today, thousands of people are glad that Stephanie Kwolek became a research chemist. In that job, she developed the first liquid crystal polymer. The polymer was a chemical product that formed the basis for Kevlar.

Stephanie Kwolek was born in 1923 in New Kensington, Pennsylvania. As a child, Stephanie loved science. Later, she studied chemistry and other sciences at a Pennsylvania college now known as Carnegie Mellon University.

She got a job with the DuPont chemical company in 1946. It was the beginning of a career with the company that lasted about 40 years.

By the 1960s, Dupont already had produced materials like nylon and Dacron. The company wanted to develop a new fiber. Stephanie Kwolek was part of a DuPont research group that asked to work on its development.

At the time, she was searching for a way to make a material strong enough to use on automobile tires. If tires could be improved, automobiles would need less fuel. Ms. Kwolek needed a new way to make stiff, resistant fibers for the job.

Experiments Lead to Creation of Kevlar

Her experiments for the project were supposed to produce a clear substance similar to a thick syrup. Instead, what Stephanie Kwolek produced was unexpected. It was a liquid that looked cloudy or milky. She said she might have thrown it out. But she decided to let it sit for awhile.

She told VOA that she was warned the liquid could never complete a required process. The process calls for the chemical to be pushed through the small holes of a spinneret. She remembers that the man operating the device at first refused to accept her material. He probably suspected it had solid particles that would block the holes. However, after awhile he said he would try it. She says she thinks he was tired of being asked, or might have felt sorry for her.

That person must have been surprised when the substance passed the test. It returned from the laboratory with more firmness than anything Stephanie Kwolek had made before.

Ms. Kwolek did not tell anyone that she had produced something new and strong. She said she was afraid there might have been a mistake. Repeated testing, however, did not find anything wrong. She and her group worked to improve the discovery. DuPont first manufactured large amounts of Kevlar in 1971. The material is found today in hundreds of products from sports equipment to window coverings.

Over the years, Stephanie Kwolek has received many awards. Her honors include membership in the National Inventors Hall of Fame.

Two Men Largely Responsible for Placing Kevlar in Protective Clothing

Getting Kevlar placed in protective clothing resulted mainly from the work of Lester Shubin and Nicholas Montanarelli. Mr. Shubin was educated in chemistry. He worked for the United States Army in the 1970s. At the time, Mr. Montanarelli was an Army project director. He was trained in engineering and psychology.

The two Americans were working at the Aberdeen Proving Ground in Maryland. They were searching for a way to protect people in public life from gunfire. Mr. Montanarelli knew about DuPont's recently developed fiber, and the two men decided to test it.

The men fired handguns at several materials protected by Kevlar. The material changed the shape of the bullets. It seemed a good candidate to help defend police officers and soldiers.

Mr. Shubin was able to gain financial help for a field experiment. Thousands of police officers in many cities began to wear the vests. But Mr. Montanarelli said it was difficult to get companies to make them. The companies feared legal action if the vests should fail.

Then came December 1975. A gunman shot at a policeman in Seattle, Washington. One bullet hit the officer's hand. But a bullet fired very close to the policeman struck his chest.

The officer survived. The bullet did not enter his body. He felt good enough to protest being kept in a hospital that night to make sure all was well. The incident helped get manufacturers to stop worrying about legal action. They began making the vests.

Today, about three thousand people are members of the Kevlar Survivors' Club. DuPont and the International Association of Chiefs of Police organized the group. All the members have escaped injury or death because long ago, a chemist named Stephanie Kwolek produced something unexpected.

This Science in the News was written by Jerilyn Watson. Our announcers were Shirley Griffith and Bob Doughty. I'm June Simms. Join us again next week for more news about Science in Special English on the Voice of America.

7. Millions of Americans Suffer From Hair Loss

This is Science in the News, in VOA Special English. I'm Shirley Griffith.

And I'm June Simms. Today we talk about hair. We will tell what hair is, how it grows, and some of the main reasons people lose it.

Hair has always been an important sign of beauty. This is especially true for women. Next to the face, hair is one of the main qualities people look for when they consider a woman's beauty. Whether long or short, curly or straight, hair often gets a lot of attention.

John Ertel started the Internet website for hair loss, https://www.wendangku.net/doc/e010468653.html,.

Each hair on a person's head grows from a single tube-like hole in the skin called a follicle. People are born with all of the hair follicles they are ever going to have. The average person has about one hundred

thousand hair follicles. They begin to form on a fetus around the third month of pregnancy.

The part of the hair under the skin is known as the hair root. The hair sticking out from the skin is known as the hair shaft. The shaft is made up of dead cells that have been pushed up through the root. At the base of the hair root is a small ball-like formation called a bulb. This is where new cells are formed. These cells receive nutrition from the blood supply under the skin.

As new cells form, the older cells are pushed up through the root. In time, the old cells are cut off from the blood supply and begin to form a hard protein called keratin. Keratin is the same protein found in our skin and nails. These dead cells and keratin are what make up the hair shaft. This whole process is what causes hair to grow.

Each hair grows independently of other hairs. There are three periods of hair growth. Not all hairs experience the same period of growth at the same time. The period of active growth is called Anagen. During this period, hair grows at a rate of about three tenths millimeters a day, or one centimeter a month. About 85 percent of hair follicles are going through this process at any given time. This period can last from two to six years.

The Catagen period of hair growth comes next. It is then that hair growth begins to slow down. This period usually lasts two or three weeks. Finally, hair growth comes to a complete stop and the hairs begin to fall out. This period is known as Telogen. It affects about 15 percent of all hairs at a time.

On average, a person loses between 50 and 100 hairs every day. Since each hair grows at a different rate, this process is overlooked. Once the Telogen period has ended, the hair growth process begins again.

So what happens when a person has trouble growing hair or suffers from hair loss? Your genes control how fast or how long your hair will grow. Some people have a longer than usual anagen growth period. These people may be able to grow more hair than the average person. However, others struggle to grow shoulder length hair. These people have a shorter than normal anagen period.

Your health can also affect hair growth. Poor nutrition can cause some hair follicles to stop growing or cause the hairs that grow to become weak or thin. Problems with hair growth can result from thyroid problems or other conditions like anemia, diabetes and lupus. Health experts say people who experience a sudden increase in hair loss should seek medical advice.

Some hair loss can result from a combination of genetics, aging and hormones. When this happens, the hair growth cycle changes and the hair follicles get smaller. In addition, the hairs may get thinner and shorter. Soon the hairs stop growing completely on some parts of the head. People with this condition usually have family members who have experienced similar hair losses. This kind of hair loss is known as pattern baldness. It is the most common kind of hair loss. The official medical term for the condition is androgenetic alopecia.

The Latin word alopecia means loss of hair or baldness. It is also the term used to describe the medical

condition that results in the loss of hair. Alopecia areata is the second most common form of hair loss after pattern baldness. It is the most common form of autoimmune disease. In alopecia areata, the body's defenses against disease attack the hair follicles, resulting in a loss of hair on the scalp and other parts of the body.

The condition usually begins with small round areas of hair loss on the scalp. When hair loss takes place over the whole surface of the scalp, it is called alopecia areata totalis. Sometimes a person may lose their eyebrows, eyelashes or hair on other parts of the body. This condition is called alopecia areata universalis. It is the rarest form of alopecia.

The National Alopecia Areata Foundation says alopecia areata affects about two percent of the population. About five million people in the United States have the condition. It affects people of all ages and races, and often begins in childhood.

That was true of Kayla Martell, the winner of the Miss Delaware Pageant in 2010. Ms. Martell began losing her hair when she was about 10 years old. By the time she was 13, all of her hair had come out.

Kayla Martell began competing in beauty pageants around that same time. In many of the events, she competed without hair. In fact, three of the five times she attempted to become Miss Delaware, Kayla was bald. She wore a blond wig the last time she competed, winning the competition in 2010. That win put her in position to take part in the Miss America Pageant.

Ms. Martell has used beauty pageants to help educate the public about alopecia. She compares wearing a hairpiece to other beauty queen traditions, like false eyelashes and hair weaves.

She says it is important for people to understand the emotional and social pressure that alopecia sufferers experience. She advises people with alopecia to contact a support group to tell them that they are not alone. She also says the most important form of beauty is inside out, not outside in.

Kayla Martell did not win the 2011 Miss America Pageant. But she was one of the top 10 finalists. And her public comments have helped raised public understanding of alopecia.

Except for their hair loss, many people with alopecia are healthy individuals. And, since the hair follicles are not dead, some people with alopecia can experience periods of hair growth. Ms. Martell's hair grew during the Miss America competition. Alopecia patients may grow and lose their hair several times during their life.

Scientists are not exactly sure what causes alopecia areata. It is not clear why the body's white blood cells begin to attack the cells in the hair follicles. There is no cure for the disease and no effective treatment that works for everyone.

In 2010, researchers at Columbia University Medical Center in New York reported findings that they hope will help lead to a cure. The researchers found eight genes they believe may be important in causing the condition. They said many of the genes are also linked to autoimmune diseases. These include rheumatoid arthritis, type 1 diabetes and celiac disease, a condition that affects the digestive system.

There are already effective treatments available for many of these conditions. Other treatments are being developed. The researchers say these treatments could prove to be promising for alopecia patients. Angela Christiano is a professor at Columbia University Medical Center. She also suffers from alopecia areata. She says the study gives hope that there may someday be a cure for the condition.

The researchers studied 1,054 cases from the The National Alopecia Areata Registry. They looked for similarities in the genes that people with different levels of alopecia carry. They found that those with 13 to 14 similar genes had diseases that did not progress. Those with 16 or more similar genes usually progressed to alopecia universalis, or total baldness.

The researchers hope to develop a genetic test to predict the severity of the disease. Professor Christiano says the next step is to repeat the study in future research, with a larger number of patients.

This Science in the News was written by June Simms, who was also our producer. I'm Shirley Griffith.

And, I'm June Simms. Join us again next week for more news about science on the Voice of America. 8. Vitamins are Important to Good Health

And I'm Faith Lapidus. This week, we tell about vitamins.

Many jobs must be done with two people. One person takes the lead. The other helps. It is this cooperation that brings success.

UNICEF Goodwill Ambassador Mia Farrow gives a child a dose of vitamin A, to help boost immunity, during a UNICEF-sponsored immunization Goma, capital of North Kivu Province.

So it is with the human body. Much of our good health depends on the cooperation between substances. When they work together, chemical reactions take place smoothly. Body systems are kept in balance.

Some of the most important helpers in the job of good health are the substances we call vitamins.

The word "vitamin" dates back to Polish scientist Casimir Funk in 1912. He was studying a substance in the hull that covers rice. This substance was believed to cure a disorder called beriberi.

Funk believed the substance belonged to a group of chemicals known as amines. He added the Latin word "vita," meaning life. So he called the substance a "vitamine" -- an amine necessary for life.

Funk was not able to separate the anti-berberi substance from the rice hulls. It was later shown to be thiamine. Other studies found that not all vitamines were amines. So the name was shortened to vitamin. But Funk was correct in recognizing their importance.

Scientists have discovered thirteen kinds of vitamins. They are known as vitamins A, the B group, C, D, E and K. Scientists say vitamins help to carry out chemical changes within cells. If we do not get enough of the vitamins we need in our food, we are at risk of developing a number of diseases.