(THEME)

VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English. I'm SarahLong.

VOICE TWO:

And I'm Bob Doughty. On our show this week -- new developmentsabout a British study that frightened many parents.

VOICE ONE:

A study measures the effects of dirty conditions on child growth.

VOICE TWO:

Plus ... the mystery of dark energy.

(THEME)

VOICE ONE:

Six years ago, a British studysuggested the possibility of a link between autism and the M.M.Rvaccine. Autism is a brain disorder that appears in young children.It affects communication and the ability to relate to people andenvironments. The M.M.R. vaccine is a medicine given to millions ofchildren to prevent three diseases: mumps, measles and rubella.

Thirteen scientists did the study. Their report appeared in theBritish medical magazine The Lancet. But The Lancet has nowpublished a letter from ten of those scientists. One of the otherscould not be reached. The ten withdrew the suggestion of a possiblelink between autism and the M.M.R. vaccine. They said they wish tomake clear that they never stated that the vaccine caused autism.

VOICE TWO:

The ten scientists did not include Andrew Wakefield who led thestudy. Recently he has been criticized for accepting money fromlawyers for a group of families of autistic children. The familieswanted a separate study done to support legal claims againstcompanies that make the vaccine.

Doctor Wakefield says his work for the families was no secret andcreated no conflict of interest with his study. He is reported assaying he still believes a possible connection between autism andthe vaccine needs further investigation. Lawyers for DoctorWakefield have demanded an apology from The Lancet.

VOICE ONE:

Public trust in the M.M.R. vaccine has dropped in large partbecause of the nineteen-ninety-eight study. The ten scientists saidthey recognize there have been major effects on public health. Someparents in Europe and the United States have refused the vaccine fortheir children. Doctors say this is a serious risk. Mumps, measlesand rubella can all make people very sick.

Since the study, other studies have shown no link between autismand the vaccine. Some critics say a lot of money has been wastedtrying to prove that the nineteen-ninety-eight study was false. Butothers have called the study "poor science." They note that onlytwelve children took part.

In a commentary, The Lancet points out that the vaccine issue wasonly one observation. The study dealt with bowel disease in autisticchildren. The scientists reported a possible link between boweldisease and autism. The letter just published does not dismiss thatpart of the study.

VOICE TWO:

Last November, the United States government announced a ten-yearplan to study autism. Scientists know that genetics play a part, butnot much beyond that is known.

Autism research does not have a very long history. Innineteen-forty-three, a researcher named Leo Kanner wrote about acondition that he found in eleven children. He described it as"extreme autistic loneliness." He said the children were unable torelate themselves in the normal way to people and situations "fromthe beginning of life."

Leo Kanner was a medical doctor at Johns Hopkins University, inBaltimore, Maryland. His specialty was mental health in children. Innineteen-thirty-five, he wrote what is described as the firstmedical book on child psychiatry.

(MUSIC)

VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English.

Unsafe water supplies and dirty conditions can slow the growth ofchildren. This is the finding of public health researchers fromJohns Hopkins University. Their study appears in The Lancet.

They studied two-hundred-thirty children in Peru from birth untilthree years of age. This is what they found:

By age two, children from homes with the worst conditions wereone centimeter shorter than those with the best conditions. Theyalso had fifty-four percent more cases of diarrhea. The researchersexamined the babies once a day and measured them once a month.

VOICE TWO:

But better water supplies alone did not guarantee good health.For example, some families kept water in large containers outdoors.Others kept small storage containers inside their homes. Smallcontainers can be filled more often.

But children in homes with the small containers had more cases ofdiarrhea. The researchers say this is because the containers areusually kept uncovered. So the water can get dirty more easily. Thelarge containers outside are normally kept covered.

The researchers found that other conditions could also affect thegrowth of children. Some of the children were from homes with awater connection, but not a good system for waste removal. Thesechildren were almost two centimeters shorter than those with thecleanest conditions at home.

The study ended in nineteen-ninety-eight. Doctor William Checkleyled the study. He says safe water and good sanitation are basichuman rights.

(MUSIC)

VOICE ONE:

American space scientists say Albert Einstein may have been rightafter all about what space is mostly made of. They say they havefound the best evidence yet that some form of energy pushes at anunchanging rate throughout the universe. Scientists today call thisdark energy.

Einstein had a different name for such a force. He called it acosmological constant. The German-born American physicist had atheory that this force balanced the pull of gravity. Without it,everything in the universe would crash together in the middle.Gravity would prevent the opposite. It would keep objects fromspreading apart forever.

VOICE TWO:

Einstein developed this idea in support of a general belief thatthe universe was static, unchanging. However, he rejected the ideafollowing a discovery by Edwin Hubble in nineteen-twenty-nine. TheAmerican astronomer found that the universe was expanding.

Albert Einstein later called the cosmological constant theory his"greatest blunder." Yet now, the space telescope named after EdwinHubble has gathered information to suggest this was no mistake.

VOICE ONE:

Astronomers used the Hubble Space Telescope to examine stars thatexploded thousands of millions of years ago. These stars are calledsupernovas. The scientists measured light from the supernovas. Suchmeasurements tell much about conditions at different points in thehistory of the universe.

Adam Reiss [reese] led the research at the Space TelescopeScience Institute in Baltimore. Mister Reiss says dark energyappears to stay the same even as the universe expands. He says anychange is extremely slow, if at all. He says the universe has atleast thirty-thousand-million years left. This is even if Einstein'scosmological constant theory is wrong.

VOICE TWO:

So that is good news. Yet the researchers were not able to offerany new information about one question: What is dark energy?

The only thing most scientists seem sure of is that they are notsure. Whatever it is acts in a way opposite to gravity. Gravitypulls things together. Dark energy pushes them apart.

What if dark energy ever grows stronger than gravity? Then, itcould tear all things apart. Stars, planets, even individual atomswould be destroyed. Scientists call this the "big rip."

VOICE ONE:

But some question all this. An international team recentlyannounced evidence that might conflict with the dark energy theory.The researchers studied X-rays recorded by the European satelliteobservatory XMM-Newton.

They looked at X-rays from groups of galaxies thousands ofmillions of years old. They say there are ten times more of theseclusters now. Alain Blanchard is a scientist at the AstrophysicalLaboratory in France. Mister Blanchard says these results require ahigh density of matter in the universe. He says that would leavelittle room for dark energy.

Adam Reiss tells us he is not worried about these findings. Hestudies supernovas. But he says most scientists who study galacticclusters report findings that are similar to his own. That is, auniverse filled mostly with a mysterious force they call darkenergy.

(THEME)

VOICE TWO:

SCIENCE IN THE NEWS was written by Jill Moss and Caty Weaver.Cynthia Kirk produced our program. This is Bob Doughty.

VOICE TWO:

And this is Sarah Long. Join us again next week for more newsabout science, in Special English, on the Voice of America.