PLEASE NOTE:
*
CCNet 80/2002 - 9 July 2002
----------------------------
"There's a common misconception that we're going to sit
around with
a bunch of arms experts and discuss how to blow an asteroid up.
But
we may not ever even have to consider something like that."
--Lucy McFadden, St Peterburg Times, 8 July 2002
"We're a little like cavemen getting together to decide what
to do
about a mysterious threat like forest fires. We need to
understand
asteroids better; we need to do basic science so we can talk
intelligently
about what to do."
--Dan Scheeres, St Peterburg Times, 8 July 2002
(1) ON ALERT FOR ASTEROIDS
St Petersburg Times, 8 July 2002
(2) NEW SPANISH DISH WILL AID INTERPLANETARY COMMUNICATIONS
Ron Baalke <baalke@jpl.nasa.gov>
(3) SUPER-CLUB MEANS 'GAIN AND PAIN'
BBC News Online, 9 July 2002
(4) PROJECT ORION - THE TRUE STORY OF THE ATOMIC SPACESHIP
Space.com, 9 July 2002
(5) AND FINALLY: SCIENCE NEEDS A HEALTHY NEGATIVE OUTLOOK
The New York Times, 7 July 2002
==================
(1) ON ALERT FOR ASTEROIDS
>From St Petersburg Times, 8 July 2002
http://www.sptimes.com/2002/07/08/Worldandnation/On_alert_for_asteroid.shtml
They exist in a belt beyond Mars, thousands of them, large and
small,
orbiting the sun like planets. But what would we do if one broke
free and
embarked on a collision course with Earth?
By DAVID BALLINGRUD, Times Staff Writer
If this were an old sci-fi movie, now would be the time for a
somber
gathering of the world's scientists to consider what to do about
the
approaching menace from outer space.
Outlandish ideas would be suggested and rejected. A plan would
emerge --
risky and with limited prospects for success -- but the only
option
available to a desperate world.
In the real world, Earth is not menaced by anything in outer
space -- at
least so far as we know. But many scientists have developed an
increasing
sense of urgency about the threat posed by asteroids, if only in
a cosmic
time frame.
Just last month, an asteroid the size of a football field missed
earth by a
mere 74,000 miles -- about one-third the distance to the moon.
And we didn't
even see it until it had passed us.
At summer's end, NASA will conduct a workshop to try to figure
out what we
could do if we spotted a comet or asteroid on a collision course
with our
planet.
"We're a little like cavemen getting together to decide what
to do about a
mysterious threat like forest fires," said Dan Scheeres, a
professor of
aerospace engineering.
But before a specific plan can be developed, before decisions can
be made,
"we need to understand asteroids better; we need to do basic
science so we
can talk intelligently about what to do."
Lucy McFadden, a member of the NASA team planning a mission to a
comet in
2004, said scientists feel different degrees of urgency.
"There's not the
kind of urgency such as I'm concerned about my daughter flying
into
Dallas-Fort Worth in the rain.
"But we can't predict the "when' or the "if' with
asteroids so we can't
ignore the issue either.
"We need to find out what we need to know."
* * *
Over the eons, the earth has had numerous run-ins with asteroids.
A crater
near Winslow, Ariz., caused by a relatively small asteroid, is
about 4,000
feet across. In 1908, an asteroid flattened 800 acres of forest
in Siberia.
An asteroid crashing into Earth may have ended the reign of the
dinosaurs
millions of years ago.
Worries about an asteroid collision with Earth have grown in part
because
better detection has revealed how many close calls our planet has
had.
The close call June 14 with the football-field sized asteroid was
not
detected till three days after it passed. Named 2002 MN, the
object probably
was large enough to have caused the kind of devastation Siberia
experienced
in 1908.
On March 8, asteroid 2002 EM7 passed within about 288,000 miles
of Earth.
Like the June asteroid, it came from the "blind spot"
near the sun and was
not detected until several days after it passed.
This is no cause for "doom and gloom," writes NASA
asteroid expert David
Morrison. Both were detected long before they threatened Earth,
he said.
"It makes no difference if an (asteroid) is discovered on
approach or
departure from the vicinity of the Earth," he said.
"Objects in blind spots
will be missed until they move into a more favorable geometry,
sometimes
within a few days, otherwise usually within a few years. Both of
these
asteroids were successfully found."
* * *
Asteroids are relatively small, rocky bodies orbiting the sun
like planets.
There are many thousands of them in the so-called "asteroid
belt" beyond the
orbit of Mars. Some are enormous, hundreds of miles in diameter;
some 30
feet across, or even smaller.
Most asteroids stay put in the belt, but from time to time one
gets loose --
perhaps jarred free by a collision with another asteroid, or
pulled out by
the gravitational tug from nearby Jupiter.
Earth's atmosphere protects the surface from most small
asteroids, also
called meteorites when seen from Earth. They burn up before they
strike the
ground. Larger ones, though, could pose a threat.
NASA researchers have found more than 350 near-Earth asteroids
more than a
half-mile in diameter. From this, they estimate anywhere from 500
to 1,000
similar-sized objects could be spinning around the solar system.
None has an
orbit that will bring it anywhere near Earth in the near future.
But scientists haven't found them all. Then there are the
surprise flybys,
including those from March and June.
If one were headed for a collision with Earth, mankind's only
course would
be to try to change its path somehow, or destroy it.
The workshop scheduled for September, "Scientific
Requirements for
Mitigation of Hazardous Comets and Asteroids," mostly will
deal with the
science of asteroids. Some members of the military will be
present.
"There's a common misconception that we're going to sit
around with a bunch
of arms experts and discuss how to blow an asteroid up,"
said McFadden, a
University of Maryland research professor. "But we may not
ever even have to
consider something like that."
A smorgasbord of topics are on the agenda.
Scheeres, who was on a NASA team that flew an unmanned spacecraft
to an
asteroid in February of last year, will talk about "Fancy
maneuvers:
Hovering, Hopping and Tethering."
He explained: "I've been studying how to control a
spacecraft when it is
next to or close to an asteroid's surface." Because gravity
is light and
erratic, hovering near an asteroid will be difficult. Some have
suggested a
tether might do the trick.
Putting a rover on the surface to gather soil samples will be a
headache,
too, because the light gravity might mean a rover's wheels would
not gain
traction.
"So the most efficient way to move a rover would be to have
it hop,"
Scheeres said, "to jump up and come down somewhere else to
take more
samples."
"We'll have a lot of interests represented, a lot of
mind-sets," said
workshop organizer Erik Asphaug of the University of California
at Santa
Cruz. "It will be fun."
Scheeres, from the University of Michigan, said more people are
paying
attention. "I think there is a change in awareness taking
place. I think it
began when Shoemaker-Levy hit Jupiter almost a decade ago."
>From July 16 through July 22, 1994, pieces of Comet
Shoemaker-Levy slammed
into Jupiter in a spectacular, much photographed collision -- the
first
between two solar bodies ever to be observed.
"That single event," Scheeres said, "showed people
that the solar system is
a very dynamic place, that catastrophic events are still
happening."
© Copyright St. Petersburg Times. All rights reserved.
=============
(2) NEW SPANISH DISH WILL AID INTERPLANETARY COMMUNICATIONS
>From Ron Baalke <baalke@jpl.nasa.gov>
http://www.jpl.nasa.gov/solar_system/features/spain_dsn.html
New Spanish Dish Will Aid Interplanetary Communications
Jet Propulsion Laboratory
July 8, 2002
Construction workers erecting steel components atop a new
concrete chamber
near Madrid, Spain, this summer are helping NASA study Mars and
comets.
They are building a big antenna for the Deep Space Network, which
provides
radio communications for spacecraft exploring the solar system.
The network
operates clusters of skyward-facing dish antennas at sites in
California,
Spain and Australia. The antennas catch radioed information from
spacecraft
as near as Earth orbit and as far as more than twice the distance
to Pluto.
They also send commands to the spacecraft. JPL administers the
network for
NASA.
The Spanish construction job has an important deadline.
NASA needs this new antenna operating by the time an
unprecedented peak in
demand for deep-space communications hits in November 2003, said
Jeffrey
Osman, Deep Space Network antenna and microwave manager at JPL.
During the
following three months, three rovers and two orbiters from the
United
States, Europe and Japan will arrive at Mars, two other
spacecraft will
encounter comets, and a third comet mission will launch. That's
on top of
the continuing communication needs of many other missions.
The new antenna will span 34 meters (112 feet) in diameter and
will use an
advanced design called "beam waveguide," which steers
the gathered radio
signals to a protected, underground electronics room. The design
gives more
reliable operation than the older antenna design with processing
gear up in
the dish.
"Construction is on schedule," Osman said. "The
concrete pedestal is in
place. The steel is going up. The main reflector portion of the
dish will be
lifted as a single piece later this year."
The pedestal encloses the electronics room and will support more
than 500
tons of antenna structure.
Custom-made steel pieces for the antenna's giant dish and other
components
are being fabricated at the factory in Tarragona, Spain, of the
project's
prime contractor, Schwartz-Hautmont Construcciones Metalicas,
S.A.
This antenna is the biggest piece in about $54 million worth of
improvements
NASA chose as priorities for increasing the Deep Space Network's
capabilities by November 2003.
It will become the network's sixth 34-meter, beam-waveguide
antenna. Three
are at the network's Goldstone station near Barstow, Calif. The
stations
near Madrid and near Canberra, Australia, each have one already
in
operation. Each of the three stations also has a 70-meter (230
foot) antenna
and several smaller ones.
The stations take turns linking with various spacecraft as
Earth's rotation
puts the target spacecraft in view of each station in turn.
Putting the new antenna at Madrid gives the biggest possible
advantage for
handling the upcoming peak in communications needs, including
pictures from
two advanced rovers from JPL that NASA plans to land on Mars in
early 2004.
This antenna will add about 70 hours of spacecraft-tracking time
per week
during the periods when Mars is in view of Madrid. That's a 33
percent
increase from the station's capacity with its existing antennas.
A coincidence of solar system geometry will intensify demand on
network
resources during the crunch period, Osman said: The comet
encounters by
NASA's Comet Nucleus Tour spacecraft in November 2003 and by
NASA's Stardust
spacecraft in January 2004 will happen in the same direction from
Earth as
Mars will be. That will minimize opportunities to have one
station track the
comet missions while another tracks the Mars missions.
So, the Madrid construction team keeps its work on schedule in
order to have
the new antenna ready when needed. Week-to-week progress can be
watched on
the network's Web site, at
http://deepspace.jpl.nasa.gov/dsn/antennas/madrid-gallery.html.
This month, workers will be installing a circular steel track
above the
concrete pedestal. The track will provide the precision surface
for wheels
the dish will ride on as it turns to find a distant spacecraft
with exciting
discoveries to report.
============
(3) SUPER-CLUB MEANS 'GAIN AND PAIN'
>From BBC News Online, 9 July 2002
http://news.bbc.co.uk/hi/english/sci/tech/newsid_2117000/2117494.stm
By Dr David Whitehouse
BBC News Online science editor
UK scientists will benefit tremendously by joining Eso, Europe's
premier
astronomy club - but they also know membership will bring some
pain.
Ian Halliday, chief executive of the Particle Physics and
Astronomy Research
Council (PParc), the funding body behind Britain's access to the
European
Southern Observatory's (Eso) suite of large telescopes, says
savings will
have to be made.
PParc has to find an entry fee of £80m and £12m a year
thereafter. The
government has helped but PParc has had to tighten its belt.
Dr Halliday told a media conference: "We've saved some £5m
by cutting the
operating costs of existing telescopes. We are scaling down the
use of our
existing telescopes."
UK joins astronomy super-club
But Dr Pat Roche, of Oxford University, told BBC News Online that
the
positive aspects of joining Eso and gaining access to its
world-class
telescopes far outweighed any short-term cutbacks. "The
future is very
bright," he said.
Historic setting
To explain the case for joining Eso and getting time on its
impressive
telescopes in Chile, astronomers gathered in the historic setting
of the
Great Star Room, or Octagon Room, of the Royal Observatory
Greenwich, which
was once part of the house of John Flamsteed, the first
Astronomer Royal.
Lord Sainsbury: Times have changed
Why had it taken so long to join, Dr Halliday was asked? Was this
not
another case of Britain being late in signing up to a European
institution?
He partially agreed. "The reason it has taken a while is
that policies that
were remnants of the British Empire played some kind of
roll," he said.
Lord Sainsbury, the government Minister for Science and
Innovation, gave his
full support to Britain joining Eso. He was quick to emphasise
that past
attitudes to European co-operation were no longer valid.
"With hindsight you can always see a time when you could
have done something
else. We thought we could go it alone. It looks different
today," he said.
Pain and gain
Dr Gerry Gilmore, of Cambridge University, and UK member of the
Eso Council,
looked back at when it became imperative that the UK should
become part of
Eso.
"The big change was the construction of Eso's Very Large
Telescope (VLT) at
Paranal in Chile," he said. "Before the VLT was made,
Eso was not in front.
But the VLT changed all of that. With it they forged ahead of
us."
Get inside the VLT
But finding the subscription to Eso will not be easy.
Dr Halliday said: "There is some pain but this is change.
The pain will be
in terms of redundancies but there is gain as well in terms of
new
opportunities.
"The UK's money is making all the difference to Eso.
Effectively, it is of
the right order of magnitude to pay for the new microwave
observatory, Alma.
We are all very excited about that."
'Right foot'
Dr Catherine Cesarsky, director general of Eso, was full of
optimism for
Alma.
"I'm delighted that the UK is entering Eso," she told
BBC News Online. "We
are bringing in one of the strongest European communities in
astronomy, and
since we are the strongest ground-based astronomy organisation in
Europe -
and probably the world - it makes sense.
Big boost for Alma
"I would say that if the UK didn't join, it would lose its
place in European
astronomy and world astronomy.
"Entry also means a steep increase in the Eso budget of more
than 20%, so
that makes it possible to get on with Alma without any country
having to
make large sacrifices.
"I think both sides are happy. I'm sure that there will be
things to
discuss. It won't always be a bed of roses, but we are starting
off on the
right foot."
Copyright 2002, BBC
=============
(4) PROJECT ORION - THE TRUE STORY OF THE ATOMIC SPACESHIP
>From Space.com, 9 July 2002
http://www.space.com/spacelibrary/books/library_projectorion_020709.html
by George Dyson
"In 1957, tail fins, not seat belts, were standard equipment
on American
cars. Tail fins reached a peak in popularity with the 1957
Chevrolet
Bel-Air. Powered by a 235-cubic-inch straight six or a
283-cubic-inch V-8,
with either manual overdrive or a powerglide transmission, the
Bel-Air had a
two-tone exterior, accented by anodized aluminum suggesting
space-age Los
Angeles rather than iron-age Detroit. Optional equipment, besides
seat
belts, included power windows, six-way power seats, and a
built-in electric
razor. The Russians were ahead in space, but General Motors was
ahead on the
road. This book is the story of Project Orion. In 1957, a small
group of
scientists, led by physicist Theodore B. Taylor and including my
father,
Freeman J. Dyson, launched a serious attempt to build an
interplanetary
spaceship propelled by nuclear bombs. This account, as best as I
can
reconstruct it, is the story my father could tell me only in
fragments at
the time."
- from the Preface, PROJECT ORION
Project Orion is the improbable story of the wildest idea-a space
craft
powered by hydrogen bombs-to come out of the space race.
It was the late 1950s. The Cold War was raging. Sputnik had made
its voyage
and the space race was on. On his way to school one day, George
Dyson
learned of a truly fantastical idea: massive space vehicles that
would be
powered by explosions of multiple hydrogen bombs. Among the
brilliant minds
behind this project was George's father, the eminent physicist
Freeman
Dyson.
Project Orion chronicles this fascinating episode in U.S.
scientific
research, while capturing a unique time in American history and
culture. The
project brought together a cadre of brilliant physicists, the
first such
assemblage since the Manhattan Project of fifteen years earlier.
In an
idyllic seaside community in southern California-the very picture
of 1950s
suburban prosperity-a handful of scientists, tackled a massive
project that
required the ingenuity of an engineer and the vision of a great
theoretician. Their work-ambitious but ultimately futile-took
place against
the political and cultural backdrop of the Cold War, when nuclear
technology
spelled both promise and terror.
George Dyson took the time to answer SPACE.com's questions about
Project
Orion.
SPACE.com: How difficult was it to research Project Orion?
Between the
secrecy of the science behind the spacecraft - both then and now
- as well
as the aging and passing away of many of the principal
participants, did you
feel in anyway rushed or confined by these circumstances?
George Dyson: Very difficult--everyone who worked on the project
had
Q-clearance and still has to be very careful in talking about it.
For twenty
years I kept trying to persuade someone else to write the history
of Project
Orion, which I felt should be written by someone unrelated to one
of the
principal characters. But time was running out and when another
historian's
proposal was rejected four years ago I decided to attempt it
myself. Just in
the nick of time--both because of recent deaths and illness among
the
Orioneers, and because the declassification process has now
ground to a
complete halt.
Project Orion, while wonderfully inventive, seems in retrospect
to have been
a frightening undertaking raising questions about its
environmental impact
if attempted and what impact it would have had on the Cold War.
Do you
yourself think the project should have been completed?
George Dyson: At that time we were exploding something like 100
megatons a
year in the atmosphere and Orion would have added about 1
percent. And for
good reason we decided even that was too much. It's impossible to
say what
the impact on the cold war would have been. In my view, what
really won the
cold war, in the end, was not Intercontinental Ballistic
Missiles, but the
Interstate Highway System. Had we really gone full-speed and
large scale
into deep space, the cold war would have ended sooner, I suspect.
The project's leader, Theodore B. Taylor, talks in the book about
visiting
Moscow's Red Square 36 years after he held a job trying to figure
out the
maximum damage an American nuclear weapon could do to the city
and seeing,
almost for the first time, the everyday humanity of the Russian
people. Do
you think most of the scientists involved in America's nuclear
weapons
programs were "blinded by science"? Oblivious, in a
way, to the ultimate
ends of their work?
George Dyson: No. Most atomic scientists were all too aware of
the ultimate
ends of their work. It's a real problem, today, that we are
losing that
generation of nuclear weaponeers who actually saw these weapons
explode, and
chose, like Ted (and many others, including my father) to devote
themselves
to trying to ensure that these weapons would never be used.
What most upsets you about science or scientists? What is the
most vexing
question facing scientists today?
George Dyson: What upsets me are just the usual failings of human
nature--greed, back-biting, adherence to dogma, and, especially
in some
fields, refusal to adequately credit predecessors and pioneers.
But this is
not unique to science. Obviously the most vexing question facing
us today is
what to do with the powers that the conjunction of genetics and
computing
are about to unleash. The cost of writing one byte to DNA is now
below what
one byte of core memory cost in 1959. And we know where costs
went from
there.
Who are your heroes?
George Dyson: They are covered pretty well in my three books: the
Aleut
seafarers who colonized the Aleutian Islands 10,000 years ago,
the known and
unknown pioneers of digital computing, and Ted Taylor and his
gang of
Orioneers. And lesser characters, like Jim Huscroft who lived on
Cenotaph
Island in Alaska and rowed to Juneau once a year, picked up the
year's
newspapers, and read one morning paper every day for the next
year.
If Project Orion was revived, where in solar system - or beyond -
would you
most like to travel?
George Dyson:I'll take my father's word for it: "Enceladus
still looks
good." Beyond the solar system, Orion is much too slow.
What is the most beautiful aspect to space?
George Dyson: Never having been out there, I cannot say, but I
would expect
it's looking at Earth. From an Earth perspective, it's sleeping
outside at
high altitude, under the stars.
If you controlled a $1 billion foundation, what research effort
would you
fund?
George Dyson: For the good of humanity, I would put the money
into a
completely fresh approach to the problem of alcoholism--which is
amenable to
both treatment and prevention and exacts billions upon billions
in costs.
For my own curiosity--but with unpredictable results--I would put
it into a
fresh approach to artificial intelligence, or AI.
NASA is at a crossroads and the public's interest in space
exploration
appears to have waned since the heady days of Project Orion and
then the
Apollo missions. Why should we spend money on space exploration
over say
research into deadly diseases?
George Dyson: Clearly we should do both. Why do we always ask
"over say
research into deadly diseases"? How about "over say
television or soda pop"?
And money *is* being spent, it's more a question of whether we
spend it on
things like the space station and the space shuttle, or on really
going to
interesting places and in interesting directions in space.
Copyright 2002, Space.com
================
(5) AND FINALLY: SCIENCE NEEDS A HEALTHY NEGATIVE OUTLOOK
>From The New York Times, 7 July 2002
http://www.nytimes.com/2002/07/07/weekinreview/07KOLA.html
By GINA KOLATA
IT seems a fairly obvious idea: when science experiments are
successful, the
results are published in a well-respected journal for all to see
and the
body of human knowledge expands. But the sad truth about science
is that
most experiments fail and the hypotheses that seduced researchers
turn out
not to be true or, at least, the studies provide no evidence that
they are
true. Are such studies any less important, any less successful?
And what
happens to them?
Generally, if the negative studies are large and the hypotheses
well known,
they will be published. That happened, for example, with studies
of
thousands of cellphone users finding no evidence that cellphone
radiation
predisposes to brain cancer. It also happened with a study
published last
month finding no evidence that men who had vasectomies are more
likely to
get prostate cancer.
But if the studies are small - just some professor's good idea
proved wrong
- the findings often are never published, leading future
researchers to
waste time and money going down the same blind alley. Or, if a
study that
fails to support a popularly held idea - that stress causes
ulcers, for
instance - goes unpublished, people may continue to believe in an
association that has never actually been proven.
A few new journals have begun soliciting and publishing negative
studies -
ostensibly to prevent repetition and waste, and to acknowledge
that even
negative results add value to our collective knowledge bank. It's
a tough
sell. The tendency for science to overlook most of the vast
backwash of
failed experiments isn't accidental. Money, pride, politics and
good old
competition all play a role. And even when major negative studies
are
published, it may not have the effect of moving researchers on to
other
topics.
For Dr. Bjorn Olsen, a professor of cell biology at Harvard
Medical School,
the solution to the problem of small negative studies is clear.
He is
setting up the Journal of the Negative Results in Biomedicine,
which is
expected to be online this summer.
"You have a hypothesis, based on what is commonly accepted
in an area," Dr.
Olsen said. "You do some experiments and it doesn't work out
that way.
Frequently, there is something wrong with what everyone assumes
is true."
But, he said, scientific journals like positive results,
rejecting papers
whose data fail to support a hypothesis. "These kinds of
negative results
are often very hard to get into publications," Dr. Olsen
said.
But according to Dr. Scott Kern, a professor of oncology at Johns
Hopkins
University School of Medicine, the journals aren't entirely to
blame. Some
negative data are not published, he suggests, because those
conducting the
studies do not want to share them.
Dr. Kern should know. He started his own electronic journal of
negative
results, called NOGO, which stands for Negative Observations in
Genetic
Oncology, with high hopes that cancer researchers would publish
there. He
focused on gene mutations that might predispose to cancer,
looking for
studies showing that a mutation is not associated with a cancer
rather than
ones showing it is. All he asked was that scientists fill out a
form and
post it on NOGO's Web site, letting others know not to waste
their time.
When Dr. Kern started the journal a few years ago, his colleagues
commended
him, and chuckled about it. "People would come up and pat me
on the back and
say they had a good laugh and that it was quite unique," Dr.
Kern said. But
few sent him their negative results.
"I don't know how I could make it easier for them," Dr.
Kern said. "At times
I would call people and kind of nudge them," he added, but
to little avail.
He thinks it is because scientists do not want to give their
competitors an
advantage.
"They now know something they're not going to do again and
their competitor
does not," Dr. Kern said. He said a postdoctoral student
might have spent
seven or eight months on a failed attempt. "As a consolation
to the poor
postdoc, you say, `One thing you do know is what genes not to
look at.' That
provides a warm feeling in their heart. But the moment they
submit it for
publication, that warm feeling goes away."
In an ideal world, said Dr. Leon Gordis, a professor of
epidemiology at
Johns Hopkins, all studies, positive or negative, would be judged
by whether
they were well done and whether they were interesting.
"I don't think there should be a journal of not finding
associations," Dr.
Gordis said. "If you have a good study, it should be entered
into a
prestigious medical journal."
That, of course, is what happens with studies like the ones on
cellphones,
published in The New England Journal of Medicine, The Journal of
the
American Medical Association and The Journal of the National
Cancer
Institute, or the prostate cancer study, published in The Journal
of the
American Medical Association.
But then, Dr. Gordis and others added, another complication
enters in. "On
certain controversial or emotionally charged issues, when do we
decide that
no further studies are needed?" Dr. Gordis asked.
WITH cellphones, some scientists are continuing to look for
evidence of
danger. Now, Finnish scientists have announced that they will be
reporting
on laboratory experiments that suggest that cellphone radiation
alters the
blood-brain barrier, allowing chemicals into the brain that
should be kept
out. There is, of course, no evidence that any such thing is
happening in
humans. But the very effort shows that the cellphone issue
remains alive.
Another way to keep an issue alive is to look for subgroups of
people in
large negative studies whose experience seems to support a given
hypothesis.
You can always find such subgroups if you slice the data, said
Dr. Barnett
Kramer, editor of The Journal of the National Cancer Institute.
They will
appear simply by chance, he said, adding that since the total
effect is
null, for every subgroup with a positive effect, there is another
with a
negative effect. That does not mean that the effect in any
subgroup is real
- to find out you need to do another study just with them. Should
you? Or
should a study that enrolled mostly men be repeated with women?
Should one
involving whites be done again to see if the results are the same
with
blacks?
"There's no shortage of issues that can be raised," Dr.
Gordis said. Often,
he added, there is money to be found to re-do the studies with a
different
emphasis.
So what should a scientist do?
"I'm not aware of anyone refusing money," Dr. Gordis
said. "That's the acid
test."
Copyright 2002 The New York Times Company
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