Scientific American (April 2000)

97 Pages·2000·8.9 MB·English

by  Scientific American

Surprisingly Modern Neandertals • National Medal of Technology
QUARK SOUP
CERN cooks up a
new state
of matter
see page 16
APRIL 2000 $4.95 www.sciam.com
QUANTUM
Teleportation
The Future of Travel?
Or of Computing?
Of Mice and Mensa
Genetic formula
for a smarter mouse
Brown Dwarfs
Stars that fizzled
fill the galaxy
Copyright 2000 Scientific American, Inc.
C
o
April 2000 Volume 282 Number 4
n
COVER STORY
50
t
Quantum Teleportation e
n
Anton Zeilinger
The “spookyaction ata distance” ofquantum t
NDERS mechanicsmakespossible the science-fiction dream of s
U
A teleportation—a wayto make objectsdisappear from one
HILIP S place and reappear atanother. Ithasalreadybeen
NEL/P demonstrated with photons. Yetthe greatestapplication
N
A
SPACE CH ofteleportation maybe in computing.
62
Building a Brainier Mouse
Joe Z. Tsien
To geneticallyengineer a smarter mouse, scientists
assembled some ofthe molecular componentsof learning and memory.
Understanding Clinical Trials 69 Monitoring Earth’s Vital Signs 92
Justin A. Zivin Michael D. King and David D. Herring
The journeyfrom initial A new NASAsatel-
medicalresearch to the lite—one ofa fleet
bottle in your family’s called the Earth Ob-
medicine cabinetis serving System—
complex, time-consuming usesfive state-of-
and expensive. Can the the-artsensorsto
clinicaltrialprocess better diagnose the
be refined? planet’shealth
from the sky.
The Discovery of Brown Dwarfs 76
GiborBasri
Lessmassive than starsbutmore massive TRENDS IN PALEOANTHROPOLOGY 98
than planets, brown dwarfswere long as-
Who Were the Neandertals?
sumed to be rare. New skysurveys, howev-
er, show that8in 0our galaxythe objectsmay Kate Wong, staffwriter
be ascommon asstars. Controversiesrage over
how much theywere
like usbehaviorally
The Aleutian Kayak 84 and biologically.
George B. Dyson With contributionsby
The Aleutsbuiltthese smallboatsfor hunterson the open ErikTrinkaus, Cidália
ocean. The sophisticated design isstillnotentirelyunderstood. Duarte, João Zilhão, Francesco
d’Errico andFred H. Smith.
3
Copyright 2000 Scientific American, Inc.
s
t
April 2000 Volume 282 Number 4
n
46
e
THE NATIONAL MEDAL OF TECHNOLOGY
t A report on the winners of the nation’s highest award for innovation
n
o
C
RAY KURZWEIL ROBERT A. SWANSON ROBERT W. TAYLOR GLEN JACOB CULLER
FROM THE EDITORS 8 BOOKS 114
Matt Ridley’sGenomeoffers a celebrity
LETTERS TO THE EDITORS 10 tour of human DNA, according to Dean
H. Hamer.With more from The Editors
50, 100 & 150 YEARS AGO 14
Recommend.
PROFILE 36 WONDERS, by the Morrisons 117
The long-lost lions of Los Angeles.
String theorist
and physics star CONNECTIONS, by James Burke 118
Brian Greene.
ANTI GRAVITY, by Steve Mirsky 120
TECHNOLOGY 42 END POINT 120
& BUSINESS
NEWS & ANALYSIS 16
What the “Frankenfoods”
deal means for biotech.
CERN’s little piece of the big bang. 16
CYBER VIEW 44 How deadly viruses enter the U.S. 20 16
Who wants privacy?
Refrigerating that leftover mammoth. 24
WORKING KNOWLEDGE 108
How soap and detergents work. Making plastic from feathers. 26 20
Profiting from idle computers. 27
THE AMATEUR SCIENTIST 110
by Shawn Carlson
Virtual air-traffic control. 28
A furnace in a thermos. 24
By the Numbers 30
MATHEMATICAL 112 Women and the professions.
RECREATIONS
by Ian Stewart News Briefs 32 26
Bullish on mooo-thematics.
Scientific American (ISSN 0036-8733),published monthly by Scientific American,Inc.,415 Madison Avenue,New York,N.Y.10017-1111.
Copyright ©2000 by Scientific American,Inc.All rights reserved.No part of this issue may be reproduced by any mechanical,photo-
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4
Copyright 2000 Scientific American, Inc.
EDITOR_JOHN RENNIE
s
r ®
Quantum Bits
o Established 1845
and Reliable Boats
t EDITOR IN CHIEF:John Rennie
i
MANAGING EDITOR: Michelle Press
d ASSISTANT MANAGING EDITOR: Ricki L. Rusting
NEWSEDITOR: Philip M. Yam
ASSOCIATEEDITORS: Timothy M. Beardsley, Gary Stix
E ON-LINEEDITOR: Kristin Leutwyler
Quantum teleportation and the Aleutian kayak, both forms of transporta- SENIOR WRITER: W. Wayt Gibbs
tion described in this issue, could not be more different. The former is EDITORS: Mark Alpert, Carol Ezzell, Alden M. Hayashi,
futuristic and derived from applications of quantum physics, about which Steve Mirsky, Madhusree Mukerjee, George Musser,
e Sasha Nemecek, Sarah Simpson, Glenn Zorpette
we are still learning. The latter is a historical curiosity based on prin-
CONTRIBUTING EDITORS: Graham P. Collins,
ciples of boat design centuries-old, many of which have been forgot- Marguerite Holloway, Paul Wallich
h
ten. Quantum teleportation can in theory move people and things from one place
to another without taking them through intervening points, and it can do so at the ART DIRECTOR: Edward Bell
t SENIOR ASSOCIATEART DIRECTOR: Jana Brenning
speed of light. The kayak carried hunters through rough seas at a possible top speed
ASSISTANT ART DIRECTORS: Johnny Johnson,
of about 10 knots. Quantum teleportation involves ex- Heidi Noland, Mark Clemens
m otic stuff called “entangled matter.” The kayak was PHOTOGRAPHYEDITOR: Bridget Gerety
PRODUCTION EDITOR: Richard Hunt
built of animal skin and wood.
Which of these will be more important as a form of COPYCHIEF: Maria-Christina Keller
o
transportation? I think it’s obviously the kayak. COPYAND RESEARCH: Molly K. Frances, Daniel C. Schlenoff,
Let me reemphasize the words as a form of transporta- Katherine A. Wong, Myles McDonnell, Rina Bander,
r tion. The Aleutian kayak can fall back on its record: it Sherri A. Liberman
F was a mainstay of the Aleuts’ Kayaks beat EDITORIALADMINISTRATOR: Rob Gaines
livelihood for perhaps thou- ADMINISTRATION: Eli Balough
teleporters for
sands of years. It helped
ASSOCIATEPUBLISHER, PRODUCTION: William Sherman
them tame the forbidding transportation. MANUFACTURING MANAGER: Janet Cermak
seaways around the Bering ADVERTISING PRODUCTION MANAGER: Carl Cherebin
Strait. George B. Dyson’s fascinating article on these craft begins on page 84. PREPRESSAND QUALITYMANAGER: Silvia Di Placido
PRINT PRODUCTION MANAGER: Georgina Franco
Quantum teleportation, though ingenious, is still unproved for shipping anything
PRODUCTION MANAGER: Christina Hippeli
other than photons. In science fiction, teleportation is a great convenience for ad- ASSISTANT PROJECT MANAGER: Norma Jones
vancing plots in either wonderful (see Star Trek) or horrible (see either movie version CUSTOM PUBLISHING MANAGER: Madelyn Keyes
of The Fly) directions. Of course, those imaginary teleporters disassembled people’s
ASSOCIATEPUBLISHER/VICEPRESIDENT, CIRCULATION:
atoms, zapped them through the ether and reassembled them elsewhere. Measure- Lorraine Leib Terlecki
ment uncertainties and the sheer overload of information required would make that CIRCULATION MANAGER: Katherine Robold
feat impossible. Quantum teleporters do not disassemble anything, so their mishaps CIRCULATION PROMOTION MANAGER: Joanne Guralnick
FULFILLMENT AND DISTRIBUTION MANAGER: Rosa Davis
could never produce anything quite like poor fly-headed David Hedison.
But at least for now, quantum teleportation works only one out of four times— SUBSCRIPTION [email protected]
and that 25 percent probability applies distinctly to each particle in the subject’s U.S. and Canada [phone],
Outside North America [phone]
body. What comes out at the far end of a quantum teleporter therefore still might
make even a genetically fused Jeff Goldblum blanch. Then there’s the philosophical GENERALMANAGER: Marie M. Beaumonte
quandary of whether someone who steps into a quantum teleporter is really the MANAGER, ADVERTISING ACCOUNTING AND
same person who steps out at the other end or just a duplicate, perfect down to the COORDINATION: Constance Holmes
DIRECTOR, FINANCIALPLANNING: Christian Kaiser
memories. (Somehow this never comes up in kayaking.)
For all these reasons, quantum teleportation’s application to moving matter may DIRECTOR, ELECTRONICPUBLISHING: Martin O.K. Paul
always be limited. On the other hand, as an extension of quantum computation, a
radically different way of processing information, its potential may be unlimited. As DIRECTOR, ANCILLARYPRODUCTS: Diane McGarvey
you’ll learn in Anton Zeilinger’s article beginning on page 50, it even offers a way for
CHAIRMAN EMERITUS
quantum computers to start processing information that they haven’t received yet. John J. Hanley
CHAIRMAN
Rolf Grisebach
No messages have reached me yet about this, but I know my answer to them: PRESIDENT AND CHIEFEXECUTIVEOFFICER
yes, we have redesigned some departments in the magazine. We hope the Joachim P. Rosler
changes help you identify the articles interesting to you that much more easily and [email protected]
generally enhance your reading enjoyment of Scientific American. VICEPRESIDENT
Frances Newburg
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RI
E
8 Scientific American April 2000 From the Editor
Copyright 2000 Scientific American, Inc.
s [email protected]
r
o LIVING LONGER
to lose its feedback-control mechanism:
early death resulting in the weeding out
t
In “Can Human Aging Be Postponed?” of deleterious genes. In a parallel (with a
i Michael R. Rose suggests that we could twist) to the current problem of excessive
postpone aging via natural selection by antibiotic use, which results in natural
d
delaying childbirth. This is already being selection of resistant bacterial strains, I
followed by the current generation of foresee a reduction of the natural-selec-
E
Americans, albeit for other, more imme- tion mechanism as drugs take over the
diate reasons. Marriage age has increased longevity job. We will become more and

dramatically, and the smaller family size more dependent on drugs just to hold
e
is probably the result of starting child- our ground. In other words, be careful
bearing later, rather than stopping earlier, about fooling Mother Nature.
h
as couples pursue careers that demand ROBERT P. HART
longer educations and longer working East Hampton, Conn.
t
hours. It’s interesting that we are, as a re-
sult of our affluence and technological DISSECTING THE MIND
o sophistication, adopting the very strategy
that will lead to longer life spans. Reading Antonio R. Damasio’s article FILMS
t ERIC GOLDWASSER “How the Brain Creates the Mind” SLIM
Yorktown Heights, N.Y. reminded me of something the comic
SELF-AWARENESSemergeswithin whatAn-
Emo Phillips once said: “I used to think
tonio Damasio callsthe movie-in-the-brain.
s We don’t need a genetic miracle to the brain was the most important organ
prolong healthy life. For average people in the body, until I realized who was reports, are some that model the self and
r
not smoking, regular exercise, effective telling me that.” some that model the fact that the self is
e stress management, lean weight and a LUKE E. SOISETH doing some representing of the world.
heart-healthy diet can mean 20 to 25 St. Paul, Minn. But then he inserts a non sequitur: fur-
t healthy years beyond the age of 60. ther elaboration of these lines of inquiry
THOMAS PERLS Damasio supplies a bullish account of will lead to a resolution of all questions
t
Harvard Medical School how neuroscience is moving toward a of consciousness.
e satisfactory account of consciousness, Yet it does not follow that the subjec-
Rose sees no limit to the length of time and he falls straight into a well-known tive life of the mind could, in principle,
L
human life can be extended by turning trap: a failure to distinguish the “hard” be explained by an account that confines
on antiaging genes or preparing drug problem of consciousness from other, itself to biological or computational mech-
cocktails to combat aging. But I see a less troublesome issues. Damasio writes anisms. What, for example, could a com-
problem. Any assistance provided by that neuroscience is identifying more plete map of the visual pathways ever tell
new therapies can backfire on us over the and more places in the brain where par- us about the subjective redness of the
long run. As we provide our own antiag- ticular kinds of representation are com- color red? The distinction between the
ing remedies, natural selection will begin puted. Among those representations, he hard problems of consciousness and the
lesser issues was invented recently to
eliminate the kind of confusion injected
THE_MAIL into the debate by contributors such as
Damasio, who assert that the problem is
not as difficult as everyone makes it out
READERS HAD STRONG OPINIONS about our to be and then go on to attack the wrong
December 1999 issue on “What Science Will Know in problem.
2050,” and none more forcefulthan the proteststhatthis RICHARD LOOSEMORE
“End-of-the-Millennium SpecialIssue” came a year early. Canandaigua, N.Y.
We sympathize with their pointofview, butin answer: It
may be more mathematically rigorous and precise to Damasio replies:
startthe 21stcenturyin 2001, butitisa meaninglesspre-
cision given the caprices with which calendars have As stated in my article, I propose a means
been modified over the years. Moreover, when people re- to generate, in biological terms, the sub-
fer to periodslike “the 20th century” or “the nextmillen- jective feeling that accompanies our image-
nium,” our understanding isthattheyare typicallylessconcerned with the precise making. Loosemore does not have to accept
demarcationsthan with the overallhistoricalcharacter and significance. my proposal, but the aim of my effort is
Assuch, “the 20th century” isa labelakin to “the Renaissance” or“the Victorian era.” clear: to understand not just how, say, the
The bottom line isthatifmostofthe world thinksthata new millennium hasbegun, color red is mapped but also how we have a
then for allpracticalpurposes, ithas. Additionalreader commentsconcerning articlesin subjective perspective of redness. I am neither
the December issue are featured. bullishly claiming that we know all nor that
10 Scientific American April 2000 Letters to the Editors
Copyright 2000 Scientific American, Inc.
s
we will know all, although I am convinced OTHER EDITIONS OF
r we will know a lot more. I do claim, however, SCIENTIFIC AMERICAN
that the assumed hardest part of the hard
o problem—subjectivity—may not be so hard Sandra Ourusoff
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12 Scientific American April 2000 Letters to the Editors
Copyright 2000 Scientific American, Inc.
Einstein,
o
nals, the fireman and engineer being en-
tirely protected. Its appearance is most
g
grotesque, looking not unlike a gigantic
the H-Bomb and Whale Harpoons French poodle dog.”
A
OLD HARPOONED WHALE—
“A whale has

been found with a harpoon in its body
s which, by its markings, showed that it
APRIL1950
facts as to the temperature of the ocean at must have been hurled at the whale at
r HYDROGEN BOMB: A WARNING—
“We have great depths. The data obtained up to the least thirty-six years ago.”
a to think how we can save humanity from present time shows that at a depth of 180
APRIL1850
this ultimate disaster. And we must break meters the temperature of the water re-
e the habit, which seems to have taken mains nearly invariable at all seasons. NEW WHALE HARPOON—“Capt. Robert
hold of this nation, of considering every Nearly all the deep water of the Indian Brown, of New London, Conn., has in-
Y
weapon as just another piece of machin- Ocean is below 1.7˚C, but in the North vented a most important improvement
ery and a fair means to win our struggle Atlantic and the greater part of the Pacific for shooting and capturing whales. It is

with the U.S.S.R. —Hans A. Bethe” the temperature is higher. As the depths well known that some whales of the Pa-
0 of the sea constitute an obscure region cific cannot be approached with the har-
GRAVITYEQUATION—
“The skeptic will say: where the solar rays cannot penetrate, it poon in a boat, and at best the harpoon-
5 ‘It may well be true that this system of follows that vegetable life must be absent ing and lancing of whales is a very dan-
equations is reasonable from a logical upon 93 per cent of the bottom.” gerous and difficult business. The idea of
1 standpoint. But this does not prove that it firing the harpoon out of a gun has been
SOFT ARMOR—
corresponds to nature.’ You are right, dear “The armored train has often advanced, but Capt. Brown’s har-
skeptic. Experience alone can decide on played an important part in the South poon, with the line attached, can be fired
& truth. Yet we have achieved something if African war. One memorable incident as accurately as a musket ball. The inven-
we have succeeded in formulating a mean- was the attack on the armored train at tion may be termed, ‘Whaling made suc-
ingful and precise equation. The deriva- Chieveley in which Winston Churchill cessful and easy by a Yankee Captain.’”
tion, from the questions, of conclusions was captured. As is well known, railway
0 AGE OF STEAM—
which can be confronted with experience iron and boiler plates are the usual pro- “It is said that according
will require painstaking efforts and proba- tection, but the locomotive shown in our to the late census of England, the num-
0
bly new mathematical methods. —Albert engraving was made safe in an unique ber of horses in that country has been
Einstein” manner. Rope mantlets were used for the found to have diminished from 1,000,000
1
protection of the engine on the Colenso to 200,000 within the last two years—in
ATOMIC SPY—
“The celebrated case of line. The work was done by sailors, and it other words, the Railroad have dispensed

Klaus Fuchs, atomic spy, came to a swift has been found that the rope protection with the use of 800,000 horses, and these
, end last month. Fuchs, a German Com- is a most admirable one. It is probable animals, as well as oxen, are now scarcely
0 munist who went to England in 1933 that the engine is run entirely by bell sig- used for transportation.”
and was head of theoretical physics at
5 the British atomic energy research center
at Harwell, pleaded guilty to having
transmitted atomic secrets to agents of
the U.S.S.R. Fuchs received the maxi-
mum sentence of 14 years in prison. A
strange feature of the case was that the
U.S.S.R. repudiated Fuchs’ confession.”
APRIL1900
ANTARCTIC PIONEER—
“The steamer ‘South-
ern Cross,’ with C. E. Borchgrevink, a
Norwegian, and the survivors of the
South Polar expedition, fitted out in 1898
by British publisher Sir George Newnes,
has arrived at Wellington, New Zealand.
Herr Borchgrevink reports that the mag-
netic pole has been located.” [Editors’
note: Carsten E. Borchgrevink led the first ex-
pedition to winter over on the Antarctic
mainland.] N
dSrUeNssLeEdSSth eS EGAe—og“rSaipr hiJcoahl nS ecMtiuornr aoyf tahde- NEW APPLICATION for softarmor: a locomotive for the South African war, 1900. NTIFIC AMERICA
British Association on some interesting M SCIE
O
FR
14 Scientific American April 2000 50, 100 and 150 Years Ago
Copyright 2000 Scientific American, Inc.
s PHYSICS_ELEMENTARY PARTICLES
i Fireballs of Free Quarks
s
y CERN appearsto have spotted the long-soughtquark-gluon plasma—lastseen during the big bang
l
ot every scientific discovery
aN
is heralded by a clear cry of
“Eureka!” A case in point is
n the study of an exotic state of
matter known as a quark-gluon plasma
(QGP), in which hundreds of ordinary
Aprotons and neutrons melt together and
form a fiery soup of free-roaming quarks
and gluons. The universe consisted of
such a quark stew 10 microseconds after
the big bang, about 15 billion years ago.
& Seven experiments have been gathering
data for the past six years at CERN, the Eu-
ropean laboratory for particle physics near
Geneva. Although the accumulated evi-
dence is not as direct and clear-cut as had
sbeen hoped for when the program began,
scientists conducting the experiments felt
sufficiently confident to make their Febru-
w
ary 10 announcement. “We now have
compelling evidence that a new state of
matter has been created,” said CERN theo-
e
rist Ulrich Heinz. And that state, he con-
MORE THAN 1,600 PARTICLES
tinued, “features many of the characteris-
Ntics” predicted for a quark-gluon plasma. sprayoutfrom a single collision of
Most modern high-energy particle phys- two lead nuclei, carrying evidence of
ics experiments smash together the small- a quark-gluon plasma.
est convenient particles—electrons or
protons—because the simpler the protag-
onists, the cleaner the data. The CERN ex-
periments, in contrast, use relative behe-
moths: lead nuclei composed of 208 pro- but comes in three varieties called colors. At lower energies, most of these particles
tons and neutrons. These nuclei are hurled Confinement requires that quarks group will be new hadrons, particles made up of
at almost the speed of light at a thin foil, together in sets of three whose colors confined quarks and antiquarks. At suffi-
also made of lead. On occasion, one of the blend to make “white” or in pairs of quark ciently high energy densities, however,
projectiles strikes a target nucleus, produc- and antiquark whose colors similarly can- the newly generated particles are so tight-
ing a spray of thousands of particles that cel out. Separating the component quarks ly packed together that confinement
travel on to the experimental detectors. of a particle takes a large amount of ener- stops being relevant; each quark has nu-
From these particles, physicists try to deter- gy, and instead of exposing their bare color merous companions within a femtome-
mine whether the collision momentarily charges to the world, the energy generates ter. Instead of being a hot swarmof nu-
created a seething fireball of debris, hot new quarks and antiquarks, which pair up merous hadrons colliding together and
and dense enough to set quarks loose. with any potential lone quarks to keep reacting, the fireball becomes one large
Quarks, glued together by particles aptly their colors balanced. This pairing process cloud of quarks and gluons. The tremen-
named gluons, are the basic constituents kicks in when a quark gets farther than dous energy and pressure of the quark-
of matter, making up the familiar protons about a femtometer (10–15meter)from its gluon plasma causes it to explode out-
and neutrons as well as more exotic crea- companions—the approximate size of par- ward. The temperature and density fall
tures seen only in cosmic rays and particle ticles such as protons and neutrons. and soon become too low to sustain the
accelerators. Ordinarily, quarks are locked In the CERN experiments, when the plasma state. The quarksthen rapidly pair
N
away inside their parent particles by a two lead nuclei collide, the interactions off again, forming colorless hadrons. The CER
phenomenon called confinement. Indi- between their component protons and fireball, now composed of hadrons, con- OVAL
vidual quarks carry a kind of charge that is neutrons generate a swarm of new parti- tinues expanding and cooling, and ulti- ND
somewhat analogous to electric charge cles out of the available collision energy. mately the hadrons fly on to the detectors. DRES SA
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16 Scientific American April 2000 News & Analysis
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s
Physicists have been eager to create the pairs are produced essentially as easily as plete and consistent dynamical theory
i QGP in part because it provides clues pairs of ups and downs are. The CERN ex- that described the collisions, such indi-
about the origin of the universe. The periments saw several features of enhanced rectness might be less of a concern. But
s
process of the quark fireball cooling to strangeness. When conditions were ripe such a theory does not exist: theorists must
y form hadrons (and later to form atoms) for a plasma, overall strangeness was two resort to various approximation schemes
mimics what happened during the big times higher, and a particle called omega, and computer models, incorporating
l bang. Our understanding of the uni- containing three strange quarks, occurred guesses about which processes are most
a verse’s expansion has been tested by ex- 15 times more often. Such extra enhance- significant to try to re-create the observed
periment back to the third minute, when ment of “multistrange” particles is charac- data. Indeed, some theorists will now be
n ordinary atomic nuclei formed; with the teristic of a plasma. playing devil’s advocate, doing their
quark-gluon plasma, “we have extended Whereas strangeness is enhanced in a darnedest to concoct a model involving
A our knowledge back to 10 mi- only hadron collisions that
croseconds after the big can explain all the CERN data.
bang,” says Reinhard Stock of A way to shortcut such ef-
the University of Frankfurt, forts is to obtain untainted
&
who led one of the CERN ex- evidence directly from the
periments. The explosive plasma—by studying parti-
pressure at that time was cles that do not interact
s
comparable, he remarks, to strongly with quarks and glu-
w the weight of “150 solar- ons and so can escape from
masses acting on an area the the QGP while it is still a plas-
size of a fingernail.” (Apoca- ma. They would carry direct
e
lyptists take note: the pre- signals of the extant condi-
N sumed creation of the QGP tions. For example, the forma-
did not create a mini–black tion of a QGP should greatly
hole or other Earth-destroy- increase the number of pho-
ing phenomenon, as some tons emitted. Alas, CERN’s
press reports suggested it STEW OF QUARKS (colored balls) issetfree from protonsand photon data are inconclusive,
might last year.) neutrons(grayballs) when two nuclei collide. almost swamped by the large
CERN researchers cite sev- background of photons that
eral lines of evidence that strongly indi- QGP, certain charm particles, containing are explicable without a QGP. “There are
cate they created the quark-gluon plas- the next heavier variety of quark, are sup- intriguing indications of direct photons,
ma. First are the relative numbers of pressed, as predicted in 1986. Attention fo- but they are marginal,” Heinz says.
various hadrons, which indicate the tem- cuses on the J/psi meson, which consists of Such direct evidence will have to wait
perature and energy density that must a charm quark and a charm antiquark. for the Relativistic Heavy Ion Collider, or
have prevailed when they formed. The Charm quarks are so massive that these RHIC (pronounced “rick”), at Brookhaven
result is consistent with the levels theo- charm-anticharm pairs can be produced National Laboratory in Upton, N.Y., which
retically required to produce a plasma. only during the initial extremely high en- will start examining head-on collisions of
Theenergy density is about seven times ergy proton-neutron collisions and not two beams of gold ions in the summer [see
that of ordinary nuclear matter,and the during the subsequent fireball. How many “ALittle Big Bang,” by Madhusree Muker-
fireball is expanding at 55 percent of the of the pairs remain together to be detect- jee, SCIENTIFIC AMERICAN, March 1999]. The
speed of light when the hadrons “freeze ed as J/psi mesons depends on whether usablecollision energies will be 10 times
out” of it. they had to endure a QGP: a hot, seething those of CERN’s program, which ought to
The next observed effect is enhance- plasma separates a charm quark from its produce a QGP with a higher temperature
ment of strangeness, which refers to a partner charm antiquark, so they end up and longer lifetime, allowing much clearer
type of quark. Altogether there are six dif- detected as a different species of hadron. direct observations. RHIC’s plasma should
ferent species, or “flavors,” of quark, go- The observed pattern of J/psi suppression be well above the transition point be-
ing by the whimsical names of up, down, in the CERN experiments “rules out tween a QGP and ordinary hadronic mat-
strange, charm, bottom and top. The the available conventional [explanations] ter, allowing numerous more advanced
lion’s share of ordinary matter is com- based on confined matter,” asserts Louis studies of the plasma’s properties, not
posed of the lightweight up and down Kluberg of the Laboratory of High Energy merely an uncertain demonstration that
quarks: two ups and one down quark Nuclear Physics in Palaiseau, France. it exists at all.
make a proton; one up and two downs, a All this evidence comes down on the In 2005, CERN’s Large Hadron Collider
neutron. Strange particles, produced in side of a quark-gluon plasma. Why, then, will come on-line and slam ions at 30
particle physics experiments, contain at in the words of Heinz, is this evidence times the energy level of RHIC.“We have
laenaSdstt r daoonnwgee ns tsqr, aumnagrakek siq nuagar ert kh heomera a vmnietoirq reuth adariknffi. cuuplst “dbneoeountb etc”nr eoatuhtegadht ? tao qpuroavrke- gbleuyoonn dp rleaasmsoan ahbales nTHhoaewd rh osingcrh aCetroc hlelnieddeer grt ihaerese o snfu eRrefHadcIeCed, ”at onH d“e ctihonmez Lpsaalreygtsee. of Frankfurt
tpaobr eupdnridoctadenudtc eitnh. aItnht e tth QheeGy Pes,ah wrolyhu el1dre9 b8ee0n seu rtnghuye slouervaieslltlyss dpirroTedhcute, c peirdno vwbolhelvmeinn igtsh tedh epattle atcshtmieo aen vc hiodafen npgceaesr tibisc ailcneks- theW piitcht urerep.o”rting by Uw—eG Rraeihcahmert P o. fC Soplleinks- WEBER University
are so high that strange quark-antiquark to ordinary hadrons. If there were a com- trum der Wissenschaftin Geneva. NG
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18 Scientific American April 2000 News & Analysis
Copyright 2000 Scientific American, Inc.
s EPIDEMIOLOGY_EMERGING DISEASES
i
Outbreak Not Contained
s
y
l WestNile virustriggersa reevaluation ofpublichealth surveillance
a
n he appearance of West Nile succumbing as well. In two weeks Debo- experts, the initial misidentification re-
T
virus in New York City last sum- rah S. Asnis, chief of infectious disease at mains worrisome. As Reisen points out,
A mer caught the U.S. by surprise. the Flushing Hospital Medical Center in diagnostic labs can only look for what
That this virus—which is known Queens, saw eight patients suffering simi- they know. If they don’t have West Nile
in Africa, Asia and, increasingly, in parts lar neurological complaints. After the reagents on hand, they won’t find the
& of Europe—could find its way to Ameri- third case, and despite some differences virus, just its relatives. “In California we
can shores and perform its deadly work in their symptoms, Asnis alerted the New have had only one flavivirus that we were
for many months before being identified York City Department of Health. The looking for, so if West Nile had come in
has shaken up the medical five years ago, we would have
s
community. It has revealed missed it until we had an iso-
w several major gaps in the pub- late of the virus as well,” Reisen
lic health infrastructure that comments.
may become ever more impor- This is true even though Cal-
e
tant in this era of globalization ifornia, unlike New York State,
N and emerging diseases. has an extensive, $70-million-
Because it is mosquito-borne, a-year mosquito surveillance
West Nile has reinforced the and control system. The in-
need for mosquito surveil- sects are trapped every year so
lance—something that is only that their populations can be
sporadically practiced around assessed and tested for viruses.
the country and something Surveillance has allowed Cali-
that could perhaps help doc- fornia to document the ap-
tors identify other agents caus- pearance of three new species
ing the many mysterious cases of mosquito in the past 15
of encephalitis that occur every years. In addition, 200 flocks
year. And because it killed birds of 10 sentinel chickens are sta-
before it killed seven people, tioned throughout the state.
the virus made dramatically Every few weeks during the
clear that the cultural divide summer they are tested for vi-
between the animal-health ral activity.
and the public-health commu- In 1990 sentinel chickens in
nities is a dangerous one. “It Florida detected St. Louis en-
was a tremendous wake-up call cephalitis before it infected
for the United States in gener- people. “Six weeks before the
al,” says William K. Reisen of human cases, we knew we had
the Center for Vector-Borne a big problem,” recalls Jon-
Disease Research at the Univer- athan F. Day of the Florida
sity of California at Davis. Medical Entomology Labora-
No one is certain when, or tory. After warning people to
how, West Nile arrived in New take precautions and spraying
York. The virus—one of 10 in a with insecticides, the state
family called flaviviruses, which documented 226 cases and 11
includes St. Louis encephali- AVIAN AUTOPSY: Closer attention to crow deathsmighthave deaths. “It is very difficult to
tis—could have come via a better prepared publichealth officialsfor the outbreaklastyear. say how big the problem
bird, a mosquito that had sur- would have been if we hadn’t
vived an intercontinental flight or an in- health department, in turn, contacted the known,” Day says. “But without our ac-
fected traveler. It is clear, however, that state and the Centers for Disease Control tions I think it would have been in the
West Nile started felling crows in New and Prevention (CDC), and the hunt for thousands.” (Day says surveillance in his
York’s Queens County in June and had the pathogen was on. It was first identi- county costs about $35,000 annually.)
moved into the Bronx by July, where it fied as St. Louis encephalitis, which has a New York City, home to perhaps about
cteomntbienru, ebdir dtos akti ltlh cer oBwrosn axn Zdo toh.en, in Sep- swimithil aWr ecstli Nniiclea li np trhoefi llaeb .and cross-reacts 4ve0i lslapnecciee isn o pf lamceo,s eqvueinto t, hhoausg nho s osmuceh o sfu itrs- D AP Photo
By the middle of August, people were Understandable as it is to many health neighbors—Suffolk County, Nassau Coun- B CHIL
O
B
20 Scientific American April 2000 News & Analysis
Copyright 2000 Scientific American, Inc.