Leaders Discuss AIDS in Africa / 10-Year Effort to Count Marine Life / Genes Tell What Makes a Dog / What Sleep Can Do for Memory
This is SCIENCE IN THE NEWS, from VOA Special English. I'm Sarah Long. And I'm Doug Johnson. This week -- helping people live with AIDS ... counting all the fish -- and more -- in the sea.
And, later, what makes a dog a dog ... and what sleep can do for memory.
Over forty-million people are infected with H-I-V. About three out of four live in African countries south of the Sahara Desert. H-I-V is the virus that causes the deadly disease AIDS.
Last week an international conference for people living with H-I-V and AIDS took place in Uganda. In December there will be a meeting in Senegal on caring for people with AIDS in the community and in their own homes.
But the largest African meeting on AIDS and other infections spread through sex took place in Kenya in late September. Seven thousand scientists and political leaders gathered in Nairobi for the thirteenth conference known as ICASA. They talked about ways to make sure people who have AIDS get the care they need. Many religious leaders at the conference also talked about ways to reduce the unfair treatment of people with AIDS.
People at the conference talked a lot about the newest kind of medicine, called anti-retroviral drugs. A person takes three different pills a day to suppress the virus from multiplying. This combination of drugs has been shown to help people with AIDS live longer. People who take these medicines are often able to work or go to school.
Many protesters at the conference were angry about delays in getting the medicines to more people. Kenya's health minister announced that the government will provide the drugs at reduced cost to six thousand people over the next year. One man from Kenya said he would not take any until everyone who has AIDS in Kenya can get them.
Even if poor people get the best medicines, they must also have healthy food and clean water. So there were discussions about these issues as well. In Botswana, for example, all people with H-I-V are able to get anti-retroviral medicines. But there is also a program to make sure patients have nursing care and food in their homes.
The delegates also discussed traditional medicines. However, some doctors said people should only use medicines that have been tested scientifically.
Last month, former American President Bill Clinton announced an agreement that he negotiated with four drug makers. The companies will supply lost-cost versions of three anti-retroviral drugs taken as a combination. People in nine Caribbean countries as well as Mozambique, Tanzania, Rwanda and South Africa are to receive them.
The United Nations says only three-hundred-thousand people living with AIDS in Africa currently receive anti-retroviral medicines. It says all nations must work harder and faster to fight AIDS.
Oceans cover almost seventy percent of Earth. Yet scientists say they know surprisingly little about the creatures in them. Now scientists have given the first progress report on a ten-year effort to identify all living things in the oceans.
The project is called the Census of Marine Life. Organizers met in Washington, D.C., last month to report on three years of work. The scientists hope to complete the study by two-thousand-ten.
The Census of Marine Life is expected to cost one-thousand-million dollars. Most of that money will come from governments. Hundreds of scientists from more than fifty countries are involved. A Canadian scientist, Ronald O'Dor, supervises the Census of Marine Life.
Currently, scientists know about more than two-hundred-thousand kinds of sea creatures. But they estimate that the final number could be ten times greater.
More than fifteen-thousand kinds of fish are now included in the census records. Organizers say they expect the final count to reach about twenty-thousand. Project scientists have identified an average of three new kinds of fish each week. These fish are not necessarily new, but this is the first time anyone has identified them.
The census is also identifying threatened sea creatures and areas where they mate. The scientists say pollution, climate change and the fishing industry have caused many kinds of sea life to disappear.
Scientists have made a number of discoveries during the first three years of the project. One example is a deep-sea environment near the coast of Angola. They say it contains more kinds of sea life per area than any other ocean environment known. About eighty percent of the creatures collected there were new to scientists.
Also, underwater cameras have shown that deep-sea areas are not mostly dirt, as many people believe. Corals and sponges have formed environments that the scientists call surprisingly rich. They say deep-sea areas are very important for fish and other creatures. One video showed life in the Mid-Atlantic Ocean at a depth of four-thousand-five-hundred meters.
If you ever want to build a dog, there is now a place to start. Scientists have completed the first version of the dog genome. These are the genetic instructions needed to make the animal known as man's best friend. They scientists learned more about the nature of dogs, and their genetic links to people.
The magazine Science published the findings of a team under Craig Venter of the Institute for Genomic Research in Rockville, Maryland. Doctor Venter is well-known for his work on a genetic map of humans. He used his own D-N-A in that project. For the dog project, he used cells from his black standard poodle, named Shadow.
The team used a new method of D-N-A testing. It does not provide all of the genetic information. Full genetic sequencing is more complete. That was the method used to find the instructions for humans, mice and fruit flies. But the new method takes a lot less time and money.
Doctor Venter's team placed about two-and-a-half thousand-million dog gene molecules in general order. As expected, the scientists found that dogs have more smell receptor genes in their noses than people do. This explains why dogs have such a strong sense of smell.
Craig Venter says one of the main goals was to understand the links between genes and the way dogs act. Scientists say small changes in genetic code may explain why different breeds of dogs act differently.
But the researchers also learned that we share at least seventy-five percent of our known genes with dogs. These findings may help studies of human disease, since dogs get many of the same diseases people do.
Many students try to study the whole night and not sleep before an exam. Two separate studies show this may do more harm than good. The studies found that a good night's sleep may improve memory. The findings of both studies appeared in the publication Nature.
Scientists at the University of Chicago did one of them. They trained students to listen to unclear speech produced by a machine.
Some students listened to the recording after a night of sleep. Others were tested twelve hours after the training, with no sleep. Guess what? The students who slept understood the recording better.
Professor Daniel Margoliash says sleep has at least two effects on learning. One is to strengthen memories and protect them against interference. The second is to recover memories that have been lost.
The other study took place at Harvard Medical School in Massachusetts. Scientists trained one-hundred people to repeat two series of finger movements. The act was similar to playing notes on a piano. People who slept between learning the first series and the second did the best.
The study suggested that memories are recorded in three steps. Scientists say the process is similar to the way a computer stores information. In humans, they say, the second step requires sleep. So remember that!
Science in the News was written by Karen Leggett, George Grow, Doreen Baingana and Cynthia Kirk, who was also our producer. This is Doug Johnson. And this is Sarah Long. Join us again next week for more news about science, in Special English, on the Voice of America.