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How to feed a hungry world p531

Producing enough food for the world's population in 2050 will be easy. But doing it at an acceptable cost to the planet will depend on research into everything from high-tech seeds to low-tech farming practices.


Save the census p532

The Canadian government should rethink its decision to change the way census data are collected.



Research Highlights

Palaeontology: Burrow builders p534


Physics: Mini mass p534


Geoscience: When sea ice melts p534


Materials science: Shape shifts heat tolerance p534


Ecology: Shrubs survive warming p534


Neuroscience: Movement decoded p534


Remote sensing: Great heights p535


Public health: HIV blocker p535


Astrophysics: Magnetic star p535


Animal locomotion: Gutsy move p535



Journal Club

Journal club p535

Kenji Doya




News briefing: 23–29 July 2010 p536

The week in science.


Freedom of spill research threatened p538

Scientists call for impartial funding and open data as BP and government agencies contract researchers.

Amanda Mascarelli


Therapeutic HIV vaccines show promise p539

Clinical trials hint that treatment strategy is not a dead end.

Alison Abbott


A closer look at cosmic impacts p540

Moon-crater survey could improve Solar System surface-dating methods.

Roberta Kwok


Retraction recommended for enzyme-chip paper p540

Reactome array study should not have been published, says ethics committee.

Alison Abbott


US seeks solar flair for fuels p541

Energy department launches initiative to commercialize artificial photosynthesis.

Jeff Tollefson


Fears over Europe's GM crop plan p542

A proposal to let nations opt out of growing European-approved GM varieties is under fire from all sides.

Andrea Chipman


US charges scientist with economic espionage p542

Could publishing a paper make you a spy?

Sharon Weinberger


Protein mapping gains a human focus p544

Next phase of the US Protein Structure Initiative enlists biologists to help crack tough human receptors.

Heidi Ledford



Corrections p544



News Features

Food: The growing problem p546

World hunger remains a major problem, but not for the reasons many suspect. Nature analyses the trends and the challenges of feeding 9 billion by 2050.


Food: Inside the hothouses of industry p548

Feeding the world is going to require the scientific and financial muscle of agricultural biotechnology companies. Natasha Gilbert asks whether they're up to the task.


Food: An underground revolution p552

Plant breeders are turning their attention to roots to increase yields without causing environmental damage. Virginia Gewin unearths some promising subterranean strategies.


Food: The global farm p554

With its plentiful sun, water and land, Brazil is quickly surpassing other countries in food production and exports. But can it continue to make agricultural gains without destroying the Amazon? Jeff Tollefson reports from Brazil.




Monitoring the world's agriculture p558

To feed the world without further damaging the planet, Jeffrey Sachs and 24 food-system experts call for a global data collection and dissemination network to track the myriad impacts of different farming practices.

Jeffrey Sachs, Roseline Remans, Sean Smukler, Leigh Winowiecki, Sandy J. Andelman, Kenneth G. Cassman, David Castle, Ruth DeFries, Glenn Denning, Jessica Fanzo, Louise E. Jackson, Rik Leemans, Johannes Lehmann, Jeffrey C. Milder, Shahid Naeem, Generose Nziguheba, Cheryl A. Palm, Prabhu L. Pingali, John P. Reganold, Daniel D. Richter, Sara J. Scherr, Jason Sircely, Clare Sullivan, Thomas P. Tomich & Pedro A. Sanchez


Regulation must be revolutionized p561

Unjustified and impractical legal requirements are stopping genetically engineered crops from saving millions from starvation and malnutrition, says Ingo Potrykus.

Ingo Potrykus




European Commission clarifies the rules for research audits p562

Máire Geoghegan-Quinn


Nature's readers comment online p562

A selection of responses posted on Nature's website to the News article 'Strikes could “break” Italy's universities' (Nature 466, 16–17; 2010).



Books and Arts

Vacation reading p563

Recent reviewers suggest good books to refresh your mind this summer — from a cultural history of piracy to a scientific tour of the boulevards of Paris.

Steven Shapin, W. F. Bynum, Michael Shermer, Nicky Clayton, Serge Daan, Hans von Storch, Li Gong, David Orr, Daniel Levitin, Rodrigo Quian Quiroga, Candis Callison, Jennifer Rohn, Pat Shipman, Jessica Hellmann, Abdallah Daar & Vaclav Smil



News and Views

Regenerative medicine: An eye to treating blindness p567

Work on stem cells is one of the hottest research areas in biology. But are such studies of any therapeutic value? Fortunately, yes, as is evident from successes in treating blindness.

Elena Ezhkova & Elaine Fuchs


Earthquakes: Climate and intraplate shocks p568

The heartland of the United States lies within a tectonic plate, certain regions of which have experienced large and geologically recent earthquakes. Explanations for those events are still being sought.

Mark D. Zoback


See also: Editor's summary | Letter by Calais et al.

Oceanography: Century of phytoplankton change p569

Phytoplankton biomass is a crucial measure of the health of ocean ecosystems. An impressive synthesis of the relevant data, stretching back to more than 100 years ago, provides a connection with climate change.

David A. Siegel & Bryan A. Franz


See also: Editor's summary | Article by Boyce et al.

Metabolism: Tick, tock, a β-cell clock p571

The daily light–dark cycle affects many aspects of normal physiology through the activity of circadian clocks. It emerges that the pancreas has a clock of its own, which responds to energy fluctuations.

Katja A. Lamia & Ronald M. Evans


See also: Editor's summary | Letter by Marcheva et al.

Condensed-matter physics: Bringing the noise p572

Noise is usually viewed as the bane of measurements. But a neat experiment has confirmed a long-standing prediction for an exotic electronic state of matter through the increase of noise in charge transmission.

Chetan Nayak


See also: Editor's summary | Article by Bid et al.



The four hundred years of planetary science since Galileo and Kepler p575

For 350 years after Galileo's discoveries, ground-based telescopes and theoretical modelling furnished everything known about the Sun's planetary retinue. Over the past five decades, data from spacecraft sent to all the planets and some of their satellites have shown the diversity of Solar System bodies. Many planets and satellites have changed substantially since their birth, and violent events punctuate their histories.

Joseph A. Burns


See also: Editor's summary



Observation of neutral modes in the fractional quantum Hall regime p585

The quantum Hall effect takes place in a two-dimensional electron gas under a strong magnetic field and involves current flow along the edges of the sample. In the fractional regime, counter-propagating modes that carry energy but not charge — the so-called neutral modes — have been predicted but never observed. These authors report the first direct observation of these elusive modes.

Aveek Bid, N. Ofek, H. Inoue, M. Heiblum, C. L. Kane, V. Umansky & D. Mahalu


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

Global phytoplankton decline over the past century p591

Using historical data combined with more recent satellite observations, these authors show that global phytoplankton biomass has been declining during the past century.

Daniel G. Boyce, Marlon R. Lewis & Boris Worm


See also: Editor's summary | News and Views by Siegel & Franz



Pinning quantum phase transition for a Luttinger liquid of strongly interacting bosons p597

Fluctuations arising from Heisenberg's uncertainty principle enable quantum systems to exhibit phase transitions even at zero temperature. For example, a superfluid-to-insulator transition has been observed for weakly interacting bosonic atomic gases. Here the authors report a novel type of quantum phase transition in a strongly interacting, one-dimensional quantum gas of bosonic caesium atoms. The results open up the experimental study of ultracold gases in a new regime.

Elmar Haller, Russell Hart, Manfred J. Mark, Johann G. Danzl, Lukas Reichsöllner, Mattias Gustavsson, Marcello Dalmonte, Guido Pupillo & Hanns-Christoph Nägerl


See also: Editor's summary

Direct generation of photon triplets using cascaded photon-pair sources p601

Non-classical states of light, such as entangled photon states, form an essential quantum resource. Entangled photon pairs can be created by spontaneous parametric down-conversion of laser light, but so far it has not been possible to produce photon triplets in this way. These authors report the generation of quantum-correlated photon triplets by cascaded down-conversion of a single pump photon. This should find widespread use in optical quantum technologies.

Hannes Hübel, Deny R. Hamel, Alessandro Fedrizzi, Sven Ramelow, Kevin J. Resch & Thomas Jennewein


See also: Editor's summary

Following a chemical reaction using high-harmonic interferometry p604

New methods are emerging that aim to image chemical reactions as they occur using X-ray diffraction, electron diffraction or laser-induced recollision, but spectral selection cannot be used to monitor the reacting molecules for these methods. These authors show that this apparent limitation offers opportunities for recollision-based high-harmonic spectroscopy, in which unexcited molecules can act as local oscillators against which structural and electronic dynamics is observed on an attosecond timescale.

H. J. Wörner, J. B. Bertrand, D. V. Kartashov, P. B. Corkum & D. M. Villeneuve


See also: Editor's summary

Triggering of New Madrid seismicity by late-Pleistocene erosion p608

These authors argue that the concentration of magnitude-7 or larger earthquakes in the New Madrid seismic zone since the end of the last ice age results from the recent, climate-controlled, erosional history of the northern Mississippi embayment. They show that the upward flexure of the lithosphere caused a reduction of normal stresses in the upper crust sufficient to unclamp pre-existing faults close to failure equilibrium.

E. Calais, A. M. Freed, R. Van Arsdale & S. Stein


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

Convergent evolution of chicken Z and human X chromosomes by expansion and gene acquisition p612

Birds and mammals have distinct sex chromosomes: in birds, males are ZZ and females ZW; in mammals, males are XY and females XX. By sequencing the chicken Z chromosome and comparing it with the human X chromosome, these authors overturn the currently held view that these chromosomes have diverged little from their autosomal progenitors. The Z and X chromosomes seem to have followed convergent evolutionary trajectories, despite evolving with opposite systems of heterogamety.

Daniel W. Bellott, Helen Skaletsky, Tatyana Pyntikova, Elaine R. Mardis, Tina Graves, Colin Kremitzki, Laura G. Brown, Steve Rozen, Wesley C. Warren, Richard K. Wilson & David C. Page


See also: Editor's summary

Sparse coding and high-order correlations in fine-scale cortical networks p617

Sensory cortical neurons are interconnected at different scales, and this could be related to differences in functional interactions. Using maximum entropy models, these authors explore the correlation structure of neurons in primary visual cortex of anaesthetized monkeys recorded using multiple tetrodes. They conclude that distant neurons display pairwise correlations but that local networks can have more complex interactions that may act to sparsify the neural code.

Ifije E. Ohiorhenuan, Ferenc Mechler, Keith P. Purpura, Anita M. Schmid, Qin Hu & Jonathan D. Victor


See also: Editor's summary

Regulation of parkinsonian motor behaviours by optogenetic control of basal ganglia circuitry p622

It has long been thought that motor control is achieved through the balanced activity of two distinct pathways through the basal ganglia that have opposing effects, but this has never been functionally verified. These authors directly test this hypothesis with optogenetic activation of different populations of mouse striatal neurons, and not only trace functional connectivity but demonstrate opposing effects on motor behaviour in a parkinsonian model.

Alexxai V. Kravitz, Benjamin S. Freeze, Philip R. L. Parker, Kenneth Kay, Myo T. Thwin, Karl Deisseroth & Anatol C. Kreitzer


See also: Editor's summary

Disruption of the clock components CLOCK and BMAL1 leads to hypoinsulinaemia and diabetes p627

Circadian rhythms control many physiological functions. During periods of feeding, pancreatic islets secrete insulin to maintain glucose homeostasis — a rhythmic process that is disturbed in people with diabetes. These authors show that pancreatic islets contain their own clock: they have self-sustained circadian oscillations of CLOCK and BMAL1 genes and proteins, which are vital for the regulation of circadian rhythms. Without this clock, a cascade of cellular failure and pathology initiates the onset of diabetes mellitus.

Biliana Marcheva, Kathryn Moynihan Ramsey, Ethan D. Buhr, Yumiko Kobayashi, Hong Su, Caroline H. Ko, Ganka Ivanova, Chiaki Omura, Shelley Mo, Martha H. Vitaterna, James P. Lopez, Louis H. Philipson, Christopher A. Bradfield, Seth D. Crosby, Lellean JeBailey, Xiaozhong Wang, Joseph S. Takahashi & Joseph Bass


See also: Editor's summary | News and Views by Lamia & Evans

Cross-species genomics matches driver mutations and cell compartments to model ependymoma p632

Ependymoma is a type of neural tumour that arises throughout the central nervous system. Using comparative transcriptomics in mouse and human tumours, these authors home in on mutations that are specific to individual tumour subgroups. In doing so, they generate the first mouse model of ependymoma and demonstrate the power of interspecific genomic comparisons to interrogate cancer subgroups.

Robert A. Johnson, Karen D. Wright, Helen Poppleton, Kumarasamypet M. Mohankumar, David Finkelstein, Stanley B. Pounds, Vikki Rand, Sarah E. S. Leary, Elsie White, Christopher Eden, Twala Hogg, Paul Northcott, Stephen Mack, Geoffrey Neale, Yong-Dong Wang, Beth Coyle, Jennifer Atkinson, Mariko DeWire, Tanya A. Kranenburg, Yancey Gillespie, Jeffrey C. Allen, Thomas Merchant, Fredrick A. Boop, Robert. A. Sanford, Amar Gajjar, David W. Ellison, Michael D. Taylor, Richard G. Grundy & Richard J. Gilbertson


See also: Editor's summary

Pathogenic LRRK2 negatively regulates microRNA-mediated translational repression p637

LRRK2 activity is dysregulated in Parkinson's disease, but how it contributes to the pathogenesis is unknown. These authors show that Drosophila LRRK2 interacts with the Argonaute component (dAgo1) of the RNA-induced silencing complex. This is associated with reduced levels of dAgo1, interaction between phospho-4E-BP1 and hAgo2, and impairment of microRNA-mediated repression. This leads to overexpression of the cell cycle genes e2f1 and dp, and consequent degeneration of dopaminergic neurons.

Stephan Gehrke, Yuzuru Imai, Nicholas Sokol & Bingwei Lu


See also: Editor's summary

New class of gene-termini-associated human RNAs suggests a novel RNA copying mechanism p642

In the course of characterizing short RNAs from human cells using single-molecule high-throughput sequencing, these authors identify a new short RNA species. The presence of non-genomically encoded poly(U) residues at their 5' ends implies the existence of an unknown RNA copying mechanism in human cells.

Philipp Kapranov, Fatih Ozsolak, Sang Woo Kim, Sylvain Foissac, Doron Lipson, Chris Hart, Steve Roels, Christelle Borel, Stylianos E. Antonarakis, A. Paula Monaghan, Bino John & Patrice M. Milos


See also: Editor's summary

Subnanometre single-molecule localization, registration and distance measurements p647

These authors have developed a method that enables them to observe single-molecule fluorescent probes with subnanometre precision and accuracy using conventional far-field fluorescence imaging. The improved resolution will enable researchers to characterize single 'molecules' of large, multisubunit biological complexes in biologically relevant environments.

Alexandros Pertsinidis, Yunxiang Zhang & Steven Chu


See also: Editor's summary



Asymptomatic deer excrete infectious prions in faeces p652

Gültekin Tamgüney, Michael W. Miller, Lisa L. Wolfe, Tracey M. Sirochman, David V. Glidden, Christina Palmer, Azucena Lemus, Stephen J. DeArmond & Stanley B. Prusiner


NLRP3 inflammasomes are required for atherogenesis and activated by cholesterol crystals p652

Peter Duewell, Hajime Kono, Katey J. Rayner, Cherilyn M. Sirois, Gregory Vladimer, Franz G. Bauernfeind, George S. Abela, Luigi Franchi, Gabriel Nuñez, Max Schnurr, Terje Espevik, Egil Lien, Katherine A. Fitzgerald, Kenneth L. Rock, Kathryn J. Moore, Samuel D. Wright, Veit Hornung & Eicke Latz





Backlash against multitasking p655

Scientists are increasingly asked to master skills in addition to their research. This is not necessarily a good thing, says Gene Russo.

Gene Russo


In Brief

Largest EU science budget p655

European Commission invests to create jobs and boost economy.


Women's health grants p655

NIH programme aims to help junior researchers gain independence.


Happier male academics p655

Nontenured faculty members in the United States come top in contentment.


Careers and Recruitment

Enlisting investigators p656

Few scientists realize that the enormous budget of the US Department of Defense includes sizeable funds for basic research. Eric Hand provides a guide for the uninitiated.

Eric Hand




Auntie Merkel p660

The course of true love.

Deborah Walker


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