Science - December 8 2006.pdf

(11512 KB) Pobierz
8 December 2006 | $10
1098380347.051.png
CONTENTS
Volume 314, Issue 5805
COVER
The grass Sorghastrum nutans , one of
a dozen plant species that dominate
native North American prairies.
Biofuels produced from diverse mixtures
of prairie plants can provide greater
energy yields and environmental
benefits than food-based biofuels
such as corn ethanol and soybean
biodiesel. See page 1598.
Photo: Jason Hill
DEPARTMENTS
1511
1512
1516
1518
1519
1521
1614
1615
EDITORIAL
1515
by Donald Kennedy
1522
1539
M. Holmberg Response E. J. Emanuel and
A. Wertheimer
N. Siegfried Response R. M. Grant et al.
Responding to Amphibian Loss J. A. Pounds et al.
Response J. R. Mendelson III et al.
1523
1525
1525
1526
1527
1543
1528
1546
F. Schätzing, reviewed by B. Worm
1529
>> Science Express Report by D. E. Canfield et al.
1547
J. Thursby and M. Thursby
1530
1533
1549
1536
1550
P. F. L. Maxted >> Report p. 1578
1551
P. Podsiadlowski and S. Justham >> Report p. 1580
1552
W. Fontana >> Reports pp. 1583 and 1585
1554
C. Kopec and R. Malinow
1555
R. Boyd >> Review p. 1560; Research Article p. 1569
1556
M. Pagani, K. Caldeira, D. Archer, J. C. Zachos
1558
CONTENTS
continued
>>
1505
SCIENCE
VOL 314
8 DECEMBER 2006
1098380347.062.png 1098380347.073.png 1098380347.076.png 1098380347.001.png 1098380347.002.png 1098380347.003.png 1098380347.004.png 1098380347.005.png 1098380347.006.png 1098380347.007.png 1098380347.008.png 1098380347.009.png 1098380347.010.png 1098380347.011.png 1098380347.012.png 1098380347.013.png 1098380347.014.png 1098380347.015.png 1098380347.016.png 1098380347.017.png 1098380347.018.png 1098380347.019.png 1098380347.020.png 1098380347.021.png 1098380347.022.png 1098380347.023.png
CONTENTS
SCIENCE EXPRESS
GEOCHEMISTRY
Late-Neoproterozoic Deep-Ocean Oxygenation and the Rise of Animal Life
D. E. Canfield, S. W. Poulton, G. M. Narbonne
A record based on iron species in minerals implies that the deep ocean only
became oxygenated after the last major Precambrian glaciation, just before
the rise of metazoans.
>> News story p. 1529
BIOCHEMISTRY
An Inward-Facing Conformation of a Putative Metal-Chelate–Type
ABC Transporter
H. W. Pinkett, A. T. Lee, P. Lum, K. P. Locher, D. C. Rees
A pump moves molecules out of cells by coupled changes in the nucleotide-binding
domain and the membrane-spanning helices, which switch the accessibility of the
central cavity from outside to inside.
MOLECULAR BIOLOGY
Secondary siRNAs Result from Unprimed RNA Synthesis and Form a
Distinct Class
T. Sijen, F. A. Steiner, K. L. Thijssen, R. H. A. Plasterk
A distinct class of small antisense RNAs is synthesized by RNA-directed RNA
polymerase from siRNA templates in Caenorhabditis elegans .
CHEMISTRY
Organic Glasses with Exceptional Thermodynamic and Kinetic Stability
S. F. Swallen et al.
Organic molecules can form stable glasses when deposited from a vapor onto a
substrate cooled only 50 kelvin below their usual glass transition temperature.
1569
S. Bowles
Early human practices requiring language and sophisticated
cognition enhanced the contribution of altruism to group survival,
perhaps selecting for altruistic traits.
>> Perspective p. 1555
PLANETARY SCIENCE
1560
M. A. Nowak
>> Perspective p. 1555
1564
1573
M. Bermejo et al.
Successive waves of Ebola virus infection and hunting pressure
are threatening the great apes of West Africa with extinction.
>> News story p. 1522
M. C. Malin et al.
Images of Mars taken 7 years apart reveal 20 new impact craters,
close to the predicted rate, some with gullies indicating the presence
of flowing water in the past decade.
>> News story p. 1528
RESEARCH ARTICLES
MICROBIOLOGY
1565
H. Alper et al.
Yeast genetically altered to tolerate higher ethanol and glucose
concentrations may prove useful for biofuel production.
1578
S. P. Littlefair
Accurate measurements of eclipses finally capture a white dwarf
cannibalizing an unseen brown dwarf companion star, confirming
long-standing predictions. >> Perspective p. 1550
CONTENTS
continued
>>
1507
SCIENCE
VOL 314
8 DECEMBER 2006
1098380347.024.png 1098380347.025.png 1098380347.026.png 1098380347.027.png 1098380347.028.png 1098380347.029.png 1098380347.030.png 1098380347.031.png 1098380347.032.png 1098380347.033.png 1098380347.034.png 1098380347.035.png 1098380347.036.png 1098380347.037.png 1098380347.038.png 1098380347.039.png 1098380347.040.png 1098380347.041.png
CONTENTS
REPORTS CONTINUED...
ASTRONOMY
1580
1601
P. P. Eggleton, D. S. P. Dearborn, J. C. Lattanzio
Three-dimensional models of giant stars show that deep convection
of supposedly stable layers destroys 3 He to levels consistent with the
Big Bang predictions. >> Perspective p. 1551
CHEMISTRY
K. M. Wassarman and R. M. Saecker
When bacteria are starved, a small RNA inhibits transcription
by folding to mimic a legitimate promoter target, after which
adding nucleotides can restart transcription.
MEDICINE
1583
1603
B. Ding and N. C. Seeman
A mechanical DNA device mounted within a crystalline
DNA lattice retains its functionality, providing a step toward
nanoscale computation and manufacturing.
>> Perspective p. 1552
CHEMISTRY
L. J. Abu-Raddad, P. Patnaik, J. G. Kublin
Malaria infection increases HIV blood levels and HIV patients are
more susceptible to malaria, a synergy that probably contributes to
the HIV epidemic in Africa.
MICROBIOLOGY
1607
1585
D. Shin, E.-J. Lee, H. Huang, E. A. Groisman
Activation of a two-component signaling pathway required
for Salmonella virulence triggers a burst of transcription
that may allow rapid adaptation to new conditions.
NEUROSCIENCE
G. Seelig, D. Soloveichik, D. Y. Zhang, E. Winfree
Single-stranded DNAs are used to create a series of computation
gates, circuits, and devices in a modular fashion.
>> Perspective p. 1552
PHYSICS
1589
1610
Qubit
S. O. Valenzuela et al.
A microwave cooling technique can lower the temperature of a qubit
to 3 millikelvin, much lower than the temperature of the surrounding
bath, enhancing its stability. >> Perspective p. 1549
ANTHROPOLOGY
Z. Liu, R. A. Neff, D. K. Berg
Acetylcholine changes chloride transporter levels, triggering a switch
from excitatory to inhibitory signaling in the embryonic chick brain.
1592
J. Walker, R. A. Cliff, A. G. Latham
Dating of cave deposits establishes the australopithicine “little foot,”
as 2.2 million years old, surprisingly recent and contemporaneous
with tool-using Homo species.
DEVELOPMENTAL BIOLOGY
1595
M.-L. Dequéant et al.
The segmentation clock, which forms repeated body structures during
development, generates many oscillating RNAs that regulate common
developmental pathways.
ECOLOGY
1598
D. Tilman, J. Hill, C. Lehman
Sustainable, higher-diversity grasslands with low-fertility soils can
yield more biomass and consume more CO 2 than equal acreages
planted with monocultured biofuel sources.
SCIENCE (ISSN 0036-8075) is published weekly on Friday, except the last week in December, by the American Association
for the Advancement of Science, 1200 New York Avenue, NW, Washington, DC 20005. Periodicals Mail postage (publication No.
484460) paid at Washington, DC, and additional mailing offices. Copyright © 2006 by the American Association for the Advancement
of Science. The title SCIENCE is a registered trademark of the AAAS. Domestic individual membership and subscription (51 issues): $139
($74 allocated to subscription). Domestic institutional subscription (51 issues): $650; Foreign postage extra: Mexico, Caribbean (surface
mail) $55; other countries (air assist delivery) $85. First class, airmail, student, and emeritus rates on request. Canadian rates with GST
available upon request, GST #1254 88122. Publications Mail Agreement Number 1069624. Printed in the U.S.A.
Change of address: Allow 4 weeks, giving old and new addresses and 8-digit account number. Postmaster: Send change of address to AAAS, P.O. Box 96178, Washington, DC 20090–6178. Single-copy sales:
$10.00 current issue, $15.00 back issue prepaid includes surface postage; bulk rates on request. Authorization to photocopy material for internal or personal use under circumstances not falling within the
fair use provisions of the Copyright Act is granted by AAAS to libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that $18.00 per article is
paid directly to CCC, 222 Rosewood Drive, Danvers, MA 01923. The identification code for Science is 0036-8075. Science is indexed in the Reader’s Guide to Periodical Literature and in several specialized indexes.
CONTENTS
continued
>>
1509
SCIENCE
VOL 314
8 DECEMBER 2006
1098380347.042.png 1098380347.043.png 1098380347.044.png 1098380347.045.png 1098380347.046.png 1098380347.047.png 1098380347.048.png 1098380347.049.png 1098380347.050.png 1098380347.052.png 1098380347.053.png 1098380347.054.png 1098380347.055.png 1098380347.056.png 1098380347.057.png 1098380347.058.png 1098380347.059.png 1098380347.060.png 1098380347.061.png 1098380347.063.png 1098380347.064.png 1098380347.065.png 1098380347.066.png 1098380347.067.png 1098380347.068.png 1098380347.069.png 1098380347.070.png
Now Av a il ab l e
Spectrum’s
M onogr aph &Controll e d
S u b st a n ce Ca t a log
G e t t hee xp e rts
beh ind y o u.
More Mo n o g ra ph Produc ts
T h an Any O th er Su ppli er
(USP, NF, FCC, EP, B P &J P)
• Se a r
ch J
ob
s
now part of
• N
ext Wav
e
•
Job Alerts
•
Resume/CV Da
t
aba
s
e
• Career Forum
Toorder your copy ca ll
877 .4 6 4. 0527
or by v isiting
• C a reer A dv ice
• M ee
a nd
A nnoun ce m e nts
• Gr a du a
tings
t
e P rogr a ms
All of the fe a ture s o n
FREE t o job seekers.
144 22 South San Pedro Street
Gardena, Ca li fornia 90248
1098380347.071.png 1098380347.072.png 1098380347.074.png 1098380347.075.png

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin