Study Finds Rise in Allergic Diseases in Children Worldwide
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This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty. And I'm Faith Lapidus. We begin our program this week with findings from an international study of allergies in children ...
Then, walking sharks? Find out about more than fifty kinds of newly found sea creatures in an area of the western Pacific ...
And we tell you about some ancient writing found in Mexico.
A study has found that the numbers of children with allergic diseases has increased worldwide, especially among younger children.
An allergy is an unusually strong reaction to something by the body's defense system. Hay fever, for example, can result from breathing particles of dust or plants. The breathing disorder asthma and the skin disease eczema are both allergic diseases.
Many different things in the environment can cause allergies. But allergic diseases may also involve genetic influences.
Innes Asher of the University of Auckland in New Zealand led the study. Professor Asher's team examined information from the International Study of Asthma and Allergies in Childhood. That study examined rates of asthma and other allergic diseases around the world. The first part of the study began in nineteen ninety-one.
The researchers repeated the study in two thousand two and two thousand three. They examined information about almost two hundred thousand children ages six and seven. These children lived in thirty-seven countries.
The researchers also looked at the records of more than three hundred thousand children ages thirteen and fourteen. These young people came from fifty-six countries including Brazil, Iran, South Africa and Sweden.
The researchers found that allergic disease rates have risen in the past fifteen years. They said the rises were more often found among younger children. The greatest increase was for eczema in the younger group. Hay fever rates rose among all groups.
Professor Asher says the average increase was about one-half of one percent a year. She says this may seem small, but it could have a major effect on public health services. And the researcher says the problem might be much worse in highly populated countries.
The results of the study appeared in the medical publication The Lancet.
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Scientists have reported finding more than fifty new kinds of sea creatures in the western Pacific Ocean. The discoveries include two kinds of sharks that appear to walk.
The sea creatures were identified during two trips to an area known as the Bird's Head Seascape earlier this year. The Bird's Head Seascape is on the northwestern end of Indonesia's Papua province.
The new kinds of shark are a major discovery for the scientists. The sharks grow to about one meter long. Unlike other sharks, they are able to walk with their fins. They do this in waters that are not deep.
The scientists reported finding twenty-two kinds of fish new to science. They also said they found twenty new kinds of hard corals, and eight new kinds of shrimp. Among the fish that, until now, were unknown to science, is a flasher wrasse. The males of this fish species change in color from brown to bright yellow, blue and purple in an effort to influence females to mate with them.
The scientists work for Conservation International, an environmental group based in Washington, D.C. Mark Erdmann led the team. Mr. Erdman says the Bird's Head Seascape may be the richest area on earth for ocean life. He says it has more kinds of sea creatures than Australia's Great Barrier Reef.
Mr. Erdmann is calling for more efforts to protect the waters near the Bird's Head peninsula. He says fishermen who use explosives are threatening the area and its ocean life. He says only about eleven percent of the area is currently protected.
Tree-cutting and increased human development could also harm the undersea wildlife. More than one thousand kinds of fish are native to the Bird's Head Seascape. So are almost six hundred kinds of hard coral.
The area also is home to whales, sea turtles, crocodiles, giant clams, manta rays, dugongs and other animals. Mark Erdmann says that without protection, they will not survive.
The oldest writing ever found in the Americas has been discovered on an ancient stone tablet. That is what a research team from Mexico and the United States announced in a report last month in Science magazine.
Road builders in the Mexican state of Veracruz found the stone by accident in the late nineteen nineties. Now, the researchers have found that the writing dates back almost three thousand years to the Olmec civilization. Writing was not thought to exist in the New World until about four hundred years later.
Sixty-two signs are cut into the stone. The team says the signs are organized in a way that follows all the expectations of writing. But the researchers say the writing system does not look like anything that came later. So it might not have been developed further.
Experts say early Egyptians and Chinese had more complex writing systems. But the discovery confirms the widespread influence of the oldest known civilization in the Americas.
The Olmec lived along the Gulf of Mexico, in the area of Mexico and Central America that archeologists call Mesoamerica. The tablet was found at a place called Cascajal.
The Olmec used pictures to tell stories, but earlier discoveries of a possible writing system were disputed. Several experts said the new report provides strong evidence that the Olmec did, in fact, have a writing system.
Stephen Houston of Brown University in Providence, Rhode Island, is a member of the team that examined the stone. The anthropology professor says it is not surprising that the Olmec had a writing system. What is surprising, he says, is that no such evidence had been found before.
The Olmec people are best known for creating stone heads more than two meters tall. These huge heads were found in places thought to be religious centers.
Scientists have found that Olmec society was highly developed and the people built the first large cities in what is now Mexico. The Olmec influenced other civilizations that followed.
The stone tablet is thirty-six centimeters long and twenty-one wide. It is thirteen centimeters thick and weighs almost twelve kilograms. The green stone is made of the mineral serpentine. The side with the writing appears to have been used repeatedly as a writing surface.
Twenty-nine different symbols are organized in lines on the tablet. Some of the symbols, or glyphs, appear as many as four times. The tablet includes images of everyday life, such as maize and possibly fish. The stone is weather-beaten and the writing is difficult to read after all these years.
Yet the way signs are used together in some places even suggests examples of poetic expression.
But there is one problem with the writing: no one understands what it means.
Professor Houston says he believes the tablet may have been used in ceremonies. He says some of the writing might relate to rulers in Olmec society. One thing it does not appear to be is a financial statement, since none of the marks look like numbers.
Maybe you can understand what the writing says. You can see a picture of the Cascajal tablet at voaspecialenglish.com.
Plant researchers have developed genetically engineered rice that they say can survive flooding for as long as two weeks. Rice plants are generally grown in standing water. But most will die if they are completely underwater for more than a few days.
The scientists say they found a rice gene that could lead to more secure food supplies for populations that depend on rice. This gene, when made to become very active, improves the ability of rice plants to survive longer underwater.
Teams from the International Rice Research Institute in the Philippines and the University of California made the discovery. Their report appeared in Nature magazine. The scientists say the experimental rice is being tested in Laos, Bangladesh and India.
Our program was written by Lawan Davis, Jerilyn Watson and Brianna Blake who was also our producer. Internet users can download transcripts and audio files at voaspecialenglish.com. I'm Bob Doughty. And I'm Faith Lapidus. Please join us again next week for more news about science in Special English on the Voice of America.