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Do scientists really need a PhD? p7

Young scientists at a Chinese genomics institute are foregoing conventional postgraduate training for the chance to be part of major scientific initiatives. Is this the way of the future?


The ratings game p7

International university rankings need to be improved — and interpreted more wisely.


The bigger picture p8

General science meetings are good opportunities for researchers to broaden their horizons.



Research Highlights

Biology: Secret code p10


Genetics: Gene guards p10


Nanotechnology: Light DNA machine p10


Electronics: Caught on film p10


Biology: Stayin' alive p10


Astrophysics: Old stars call out p10


Chemical biology: With added sugar p11


Applied physics: Sound lasers hum along p11


Wildlife biology: Lizard back burden p11


Neuroscience: Use it or lose it p11



Journal Club

Journal club p11

Robert Lucas




News briefing: 4 March 2010 p12

The week in science


Model response to Chile quake? p14

Experts debate how much emergency-response planners should rely on tsunami forecasts.

Quirin Schiermeier


Unmanned planes take wing for science p14

Drones will measure ozone and aerosols in the atmosphere.

Jeff Tollefson


University rankings smarten up p16

Systems for ranking the world's higher-education and research institutions are about to become more sophisticated, says Declan Butler.

Declan Butler


Fat rats skew research results p19

Overfed lab animals make poor subjects for experiments.

Daniel Cressey


The labours of Fotis Kafatos p20

Launching the European Research Council was a Herculean effort, says its outgoing president.

Natasha Gilbert


Weapons labs to thrive as Obama trims nukes p21

President takes first steps towards goal of disarmament.

Jeff Tollefson



News Features

Chinese bioscience: The sequence factory p22

The bold ambitions of one institute could make China the world leader in genome sequencing. David Cyranoski asks if its science will survive the industrial ramp-up.


Non-proliferation: Borderline detection p26

Georgia's borders are guarded by some of the best radiation detectors available — so why are nuclear smugglers still slipping through? Sharon Weinberger reports.




World view: Curing climate backlash p28

Effective action on climate requires better politics, not better science, explains Daniel Sarewitz.

Daniel Sarewitz




South Africa: telescopes raise the nation's sights p30

Patricia Whitelock


South Africa: aiming to be premier global astronomy hub p30

Rob Adam


South Africa: big science should stay on the agenda p30

Steven L. Chown


Myth-busting about first mass-produced human cell line p30

Leonard Hayflick


Spring awakening planned for Mars rover Spirit p31

Steve Squyres


Esaki diode is still a radio star, half a century on p31

Leo Esaki, Yasuhiko Arakawa & Masatoshi Kitamura


Foundations could allocate money more productively p31

Ingrid Eisenstadter




Stop laser uranium enrichment p32

The US Congress should discourage efforts to advance the technology to make fuel for nuclear reactors, say Francis Slakey and Linda R. Cohen — the risks outweigh the benefits.

Francis Slakey & Linda R. Cohen



Books and Arts

Is there anybody out there? p34

Paul Davies's latest book argues that the search for intelligent life beyond Earth should be expanded. Chris McKay considers why we should look closer to home — perhaps even in our DNA.

Chris McKay reviews The Eerie Silence: Renewing Our Search for Alien Intelligence/Are We Alone In The Universe? by Paul Davies


Why you shouldn't always follow the crowd p35

Mark Buchanan reviews The Perfect Swarm: The Science of Complexity in Everyday Life by Len Fisher


Autism and animal insight p35

Wes Jamison & Clive Wynne review Temple Grandin Directed by Mick Jackson


Q&A: Joanna Cole on writing science books for kids p36

Joanna Cole has authored more than 100 science books for children, including the best-selling Magic School Bus series, the latest edition of which tackles the topic of climate change. In the last of our series of interviews with authors who write science books for different audiences, Cole reveals how clarity and colour can introduce even very young children to science.

Nicola Jones



News and Views

Behavioural neurobiology: The treacherous scent of a human p37

Mosquitoes' odorant receptors help the insects to find humans and, inadvertently, to transmit malaria. The identification of the odorants that bind to these receptors opens up ways of reducing mosquito biting.

Walter S. Leal


See also: Editor's summary

Microscopy: When mica and water meet p38

A neat mode of operation of the atomic force microscope has been used to probe the interface between mica and water. The results help to settle a long-standing debate about the nature of this interface.

Joost W. M. Frenken & Tjerk H. Oosterkamp


50 & 100 years ago p39


Materials science: Hydrocarbon superconductors p39

Superconductivity has been discovered in the materials that form when alkali metals react with a solid hydrocarbon. This is the first new class of organic, high-temperature superconductor in a decade.

Matthew J. Rosseinsky & Kosmas Prassides


See also: Editor's summary

Clinical immunology: Culprits with evolutionary ties p41

The cellular organelles we know as mitochondria are thought to have originated as symbiotic bacteria. Indeed, the two use common mechanisms to trigger innate immune responses to injury and infection, respectively.

Carolyn S. Calfee & Michael A. Matthay


See also: Editor's summary

Materials science: Mind the helical crack p42

Catastrophic breakage of brittle materials such as ceramics is usually triggered by the rapid spreading of cracks. Computer simulations have now cracked the three-dimensional details of this process.

Markus J. Buehler & Zhiping Xu


See also: Editor's summary

Developmental genetics: Time for teeth p43

Sadaf Shadan


Obituary: Marshall Nirenberg (1927–2010) p44

A humble, gentle and visionary giant of molecular biology.

C. Thomas Caskey




Quantum computers p45

T. D. Ladd, F. Jelezko, R. Laflamme, Y. Nakamura, C. Monroe & J. L. O’Brien


See also: Editor's summary



Remarkably ancient balanced polymorphisms in a multi-locus gene network p54

Local adaptations are often governed by several interacting genes scattered throughout the genome. Here a novel type of multi–locus genetic variation is described that has been maintained within a species over a vast period of time. A balanced unlinked gene network polymorphism is dissected that involves galactose utilization in a close relative of baker's yeast.

Chris Todd Hittinger, Paula Gonçalves, José Paulo Sampaio, Jim Dover, Mark Johnston & Antonis Rokas


See also: Editor's summary

A human gut microbial gene catalogue established by metagenomic sequencing p59

Deep metagenomic sequencing and characterization of the human gut microbiome from healthy and obese individuals, as well as those suffering from inflammatory bowel disease, provide the first insights into this gene set and how much of it is shared among individuals. The minimal gut metagenome as well as the minimal gut bacterial genome is also described.

Junjie Qin, Ruiqiang Li, Jeroen Raes, Manimozhiyan Arumugam, Kristoffer Solvsten Burgdorf, Chaysavanh Manichanh, Trine Nielsen, Nicolas Pons, Florence Levenez, Takuji Yamada, Daniel R. Mende, Junhua Li, Junming Xu, Shaochuan Li, Dongfang Li, Jianjun Cao, Bo Wang, Huiqing Liang, Huisong Zheng, Yinlong Xie, Julien Tap, Patricia Lepage, Marcelo Bertalan, Jean-Michel Batto, Torben Hansen, Denis Le Paslier, Allan Linneberg, H. Bjørn Nielsen, Eric Pelletier, Pierre Renault, Thomas Sicheritz-Ponten, Keith Turner, Hongmei Zhu, Chang Yu, Shengting Li, Min Jian, Yan Zhou, Yingrui Li, Xiuqing Zhang, Songgang Li, Nan Qin, Huanming Yang, Jian Wang, Søren Brunak, Joel Doré, Francisco Guarner, Karsten Kristiansen, Oluf Pedersen, Julian Parkhill, Jean Weissenbach, MetaHIT Consortium, Peer Bork, S. Dusko Ehrlich & Jun Wang


See also: Editor's summary

Odorant reception in the malaria mosquito Anopheles gambiae p66

Insect vectors of diseases locate their animal hosts through olfaction via largely unknown molecular processes. Here the 'empty neuron' system of genetically engineered Drosophila is used to assign specific odorants to the entire repertoire of olfactory receptors of the malaria vector Anopheles gambiae. The results illuminate ecological and neurobiological differences between mosquitoes and fruitflies and provide new potential molecular targets to boost the struggle against insect–borne diseases.

Allison F. Carey, Guirong Wang, Chih-Ying Su, Laurence J. Zwiebel & John R. Carlson


See also: Editor's summary | News and Views by Leal



Linking dwarf galaxies to halo building blocks with the most metal-poor star in Sculptor p72

Current models indicate that the Milky Way's stellar halo was assembled from many smaller systems, and recent studies claimed that the true Galactic building blocks must have been vastly different from the surviving dwarfs. But the overall abundance pattern of elements in S1020549, the most iron-poor star in the Sculptor dwarf galaxies, is now found to follow that seen in low-metallicity halo stars, indicating that the systems destroyed to form the halo billions of years ago were not fundamentally different from the progenitors of present-day dwarfs.

Anna Frebel, Evan N. Kirby & Joshua D. Simon


See also: Editor's summary

Superconductivity in alkali-metal-doped picene p76

The phenomenon of superconductivity continues to intrigue, and several new superconducting materials have been discovered in recent years — but in the case of organic superconductors, no new material system with a high superconducting transition temperature has been identified in the past decade. Now it has been shown that the introduction of potassium into crystals of organic molecule picene can yield superconductivity at temperatures as high as 18 K.

Ryoji Mitsuhashi, Yuta Suzuki, Yusuke Yamanari, Hiroki Mitamura, Takashi Kambe, Naoshi Ikeda, Hideki Okamoto, Akihiko Fujiwara, Minoru Yamaji, Naoko Kawasaki, Yutaka Maniwa & Yoshihiro Kubozono


See also: Editor's summary | News and Views by Rosseinsky & Prassides

Reinventing germanium avalanche photodetector for nanophotonic on-chip optical interconnects p80

To integrate microchips with optical communications a photodetector is required to mediate the optical and electronic signals. Although germanium photodetectors are compatible with silicon their performance is impaired by poor intrinsic noise. Here the noise is reduced by nanometre engineering of optical and electrical fields to produce a compact and efficient photodetector.

Solomon Assefa, Fengnian Xia & Yurii A. Vlasov


See also: Editor's summary

Helical crack-front instability in mixed-mode fracture p85

The addition of shear orthogonal to the tension-loading plane of crack propagation generates an instability that results in three-dimensional helical crack propagation, atomically rough surfaces and a fracture pattern resembling a series of lance shapes. Here numerical simulations reveal a new law that governs crack propagation in space for materials subject to general stress conditions.

Antonio J. Pons & Alain Karma


See also: Editor's summary | News and Views by Buehler & Xu

Metabolic streamlining in an open-ocean nitrogen-fixing cyanobacterium p90

UCYN–A is a recently discovered nitrogen-fixing cyanobacterium with unusual metabolic features. The complete genome of this uncultivated organism is now presented, revealing a photofermentative metabolism and dependency on other organisms for essential compounds.

H. James Tripp, Shellie R. Bench, Kendra A. Turk, Rachel A. Foster, Brian A. Desany, Faheem Niazi, Jason P. Affourtit & Jonathan P. Zehr


See also: Editor's summary

Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira p95

A new genus and species is described from fragmentary remains of a reptile from the mid–Triassic of Tanzania. The finding clarifies the relationships among the silesaurs. It is among the earliest known ornithodirans (dinosaurs plus pterosaurs), and demonstrates that silesaurs were not two-legged carnivores, as expected, but larger and more herbivorous. Furthermore, the find shows that we still know very little about the earliest stages of dinosaur and pterosaur evolution.

Sterling J. Nesbitt, Christian A. Sidor, Randall B. Irmis, Kenneth D. Angielczyk, Roger M. H. Smith & Linda A. Tsuji


See also: Editor's summary

Changes in Hox genes’ structure and function during the evolution of the squamate body plan p99

The organization of Hox clusters in several different reptiles is investigated, showing that the Hox clusters in squamates — lizards and snakes — have unexpectedly accumulated transposable elements, reflecting extensive genomic rearrangements of coding and non coding regulatory regions. Comparative expression analyses between two species showing different axial skeletons, the corn snake and the whiptail lizard, revealed major alterations in Hox13 and Hox10 expression features during snake somitogenesis, in line with the expansion of both caudal and thoracic regions.

Nicolas Di-Poï, Juan I. Montoya-Burgos, Hilary Miller, Olivier Pourquié, Michel C. Milinkovitch & Denis Duboule


See also: Editor's summary

Circulating mitochondrial DAMPs cause inflammatory responses to injury p104

Severe trauma can lead to death and sepsis in the absence of apparent infection. Here evidence shows that mitochondrial debris, released from damaged cells, is present in the circulation of seriously injured trauma patients. Such debris is shown to activate neutrophils via specific formyl peptide receptors, triggering systemic inflammation and end organ injury.

Qin Zhang, Mustafa Raoof, Yu Chen, Yuka Sumi, Tolga Sursal, Wolfgang Junger, Karim Brohi, Kiyoshi Itagaki & Carl J. Hauser


See also: Editor's summary | News and Views by Calfee & Matthay

Haematopoietic stem cells derive directly from aortic endothelium during development p108

One of two papers showing the generation of haematopoietic stem cells (HSCs) from the ventral wall of the dorsal aorta in live zebrafish embryos. Here, combined fluorescent reporter transgenes, confocal time-lapse microscopy and flow cytometry identify and isolate the stepwise intermediates as aortic haemogenic endothelium transitions to nascent HSCs. HSCs generated from this haemogenic endothelium are the lineal founders of virtually all of the adult haematopoietic system.

Julien Y. Bertrand, Neil C. Chi, Buyung Santoso, Shutian Teng, Didier Y. R. Stainier & David Traver


See also: Editor's summary

Blood stem cells emerge from aortic endothelium by a novel type of cell transition p112

One of two papers showing the generation of haematopoietic stem cells (HSCs) from the ventral wall of the dorsal aorta in live zebrafish embryos. Here, using imaging of live zebrafish, HSCs are shown to emerge directly from the aorta floor. This process does not involve cell division but movement of single endothelial cells out of the aorta ventral wall into the sub aortic space, where they transform into haematopoietic cells.

Karima Kissa & Philippe Herbomel


See also: Editor's summary

In vivo imaging of haematopoietic cells emerging from the mouse aortic endothelium p116

De novo emergence of phenotypically defined haematopoietic stem cells (Sca1+, c kit+, CD41+) directly from ventral aortic haemogenic endothelial cells is shown in mice. Although the study did not visualize live embryos, it instead developed a dissection procedure to visualize the deeply located aorta.

Jean-Charles Boisset, Wiggert van Cappellen, Charlotte Andrieu-Soler, Niels Galjart, Elaine Dzierzak & Catherine Robin


See also: Editor's summary

SIRT3 regulates mitochondrial fatty-acid oxidation by reversible enzyme deacetylation p121

During fasting SIRT3 is induced in liver and brown adipose tissue. One of SIRT3's substrates is shown to be long–chain acyl co-enzyme A dehydrogenase (LCAD). Without SIRT3 LCAD becomes hyperacetylated, which diminishes its activity, and reduces fatty acid oxidation. Mice without SIRT3 have all the hallmarks of fatty acid oxidation disorders during fasting, including reduced ATP levels and intolerance to cold. Thus, acetylation is a novel regulatory mechanism for fatty acid oxidation.

Matthew D. Hirschey, Tadahiro Shimazu, Eric Goetzman, Enxuan Jing, Bjoern Schwer, David B. Lombard, Carrie A. Grueter, Charles Harris, Sudha Biddinger, Olga R. Ilkayeva, Robert D. Stevens, Yu Li, Asish K. Saha, Neil B. Ruderman, James R. Bain, Christopher B. Newgard, Robert V. Farese Jr, Frederick W. Alt, C. Ronald Kahn & Eric Verdin


See also: Editor's summary



Opposing microRNA families regulate self-renewal in mouse embryonic stem cells p126

Collin Melton, Robert L. Judson & Robert Blelloch




Careers and Recruitment

Cultivating new talent p128

Concerns about food shortages, land use, climate change and biodiversity have created a huge need for interdisciplinary researchers focused on agriculture. Virginia Gewin investigates the opportunities.

Virginia Gewin


Correction p130




Transitions p132

Different business models for difficult times.

Dan Erlanson


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