is SCIENCE IN THE NEWS in VOA Special English. I’m Bob Doughty.
I’m Barbara Klein. This week, we will tell about an American study of media use
and mental health. We will also tell about a new treatment for people who have
lost an arm. And we will tell how spending months in space could be bad for
new study suggests that the more young people watch television, the more likely
they are to develop depression as young adults. But how much TV may or may not
be to blame is a question that the study leaves unanswered.
researchers used a national long-term survey of adolescent health to
investigate the link between media use and depression. They based their
findings on more than four thousand adolescents who were not depressed when the
survey began in nineteen ninety-five.
part of the study, the young men and women were asked how many hours of
television or videos they watched daily. They were also asked how often they
played computer games and listened to the radio.
average, each adolescent reported using some kind of media five and one-half
hours a day. More than two hours of that was spent watching TV.
years later, more than seven percent of the young people had signs of
depression. The average age at that time was twenty-one.
results of the survey were published in the Archives of General Psychiatry. The
lead writer was Brian Primack of the University of Pittsburgh medical school. He
says every extra hour of television meant an eight percent increase in the
chances of developing signs of depression.
researchers say they did not find any such link with the use of other media
such as movies, radio or video games. But the study did find that young men
were more likely than young women to develop depression given the same amount
of media use.
Primack says the study did not explore if watching TV causes depression. But
one possibility, he says, is that it may take time away from sports or other activities
that could help prevent depression. It might also interfere with sleep, he
says, and that could have an influence.
December, the publication Social Indicators Research reported on a study of
activities that help lead to happy lives. Sociologists from the University of
Maryland found that people who describe themselves as happy spend less time
watching television than unhappy people. The study found that happy people are
more likely to be socially active, read, vote and attend religious services.
are listening to the VOA Special English program SCIENCE IN THE NEWS. With
Barbara Klein, I’m Bob Doughty in Washington.
progress improves the lives of people around the world every day. One of the
latest developments is a new kind of surgery. It holds promise to greatly
improve the abilities of people who have lost both arms. The operation could
help double arm amputees move their manufactured arms with greater ease and
amputees commonly use devices joined to their shoulders to operate man-made
arms or wrists. These devices use rope-like material to carry movement from the
shoulder to the prosthetic arm. Yet, the movement is limited, and requires the
person to tighten muscles in the back or arms.
researchers with the Rehabilitation Institute of Chicago are working on another
method called TMR, or targeted muscle reinnervation. It uses the remaining nerves
of arm amputees that would otherwise be lost because of injuries.
surgically connects the remaining nerves to chest muscles. Electric devices are
then placed near those muscles. The idea is to activate the remaining arm
nerves to make electrical signals to operate prosthetic devices.
move an arm, the brain sends a message that causes the chest muscles to
tighten. An electrical signal is then sent to the prosthetic arm, telling it to
move. The process takes place without any more effort than in a person without
researchers completed a study involving five volunteers who had lost their
arms, but had the TMR surgery. They were asked to perform ten different
movements, including moving the wrist in a circular motion and moving their
group of volunteers who had not lost their arms performed the same test. The
times for both groups were similar, but the non-amputees were able to perform
the movements faster. For example, the TMR patients completed elbow and wrist
movements in an average of one-point-two-nine seconds. The non-amputee
volunteers did the movements in one-point-zero-eight seconds.
Kuiken of the Rehabilitation Institute of Chicago led the study. His team has
found that even more complex movements can be performed by TMR patients with
improved kinds of prosthetic devices. The results of the study were reported
last month in the Journal of the American Medical Association.
thirty people have already had the TMR surgery. Doctor Kuiken says the devices used
in the study need more work before they will be widely available. However, he
says they will make it possible for patients to simply think of the action they
wish to perform and do it with prosthetics.
Recently, American researchers studied a health risk
faced by astronauts traveling on the International Space Station. They found
that people who spend months in space lose bone strength at a faster rate than
experts had thought. The study found this loss of bone strength increases the
risk of broken bones later in life.
The researchers studied thirteen astronauts -- twelve
men and one woman. Each person had spent four to six months on the Space
Joyce Keyak led the study. She is a professor of
biomedical engineering and orthopedic surgery at the University of California
Her team used a computer program she developed to
identify the risk of broken hipbones in people with the bone disease
osteoporosis. The team used the same computer program to study images of the
hipbones of the thirteen astronauts.
The study found
their hipbone strength decreased by an average of fourteen percent. Three
astronauts showed losses of twenty to thirty percent. These rates are similar
to those seen in older women with osteoporosis.
The astronauts’ decrease
in bone strength measured from point six percent to five percent for each month
spent on the space station.
Professor Keyak says the measurement is much greater
than monthly reductions in bone mineral density of point four percent and one
point eight percent. Those measurements were observed in earlier studies on the
The study is said to be the first to examine in detail
measurements of bone strength instead of bone density. The American space
agency provided financial support for the study.
The results were reported in the online version of the
Researchers studying the effects of long-term
spaceflight often examine the hipbone or backbone. The hip is believed to have
the greatest rate of bone loss in space.
For many years, researchers have studied why the space
environment weakens bones. They have found that lack of gravity has a severe
effect on bones. Weightlessness does not let bones do their normal work of
supporting the body.
Professor Keyak says astronauts need to take
preventative measures to keep their bones strong. If not, she says, they may be
at increased risk for age-related broken bones years after their visits to
This SCIENCE IN THE NEWS was written by Brianna Blake,
Lawan Davis and Caty Weaver. Brianna Blake also was our producer. I’m Barbara
And I’m Bob Doughty. We would like to hear from you. Write
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