Nature contents: 17 May 2012

Can't view this email? Click here to view in your browser.     Volume 485 Number 7398      nature •Visit Nature homepage •Subscribe to Nature •View Table of Contents The science that matters. Every week.                       Southern Research offers target validation services for both in vitro systems and animal models. Our latest findings can help expand your drug's potential. Learn how.             Jump to the content that matters to you View Table of Contents ▶ ▼ News & Comment   ▼ Biological Sciences   ▼ Chemical Sciences   ▼ Physical Sciences   ▼ Earth & Environmental Sciences   ▼ Careers & Jobs       This week's highlights     Special: G protein-coupled receptors     G protein-coupled receptors (GPCRs) are membrane proteins that are involved in a broad range of biological processes, and a large number of clinically used drugs elicit their biological effect(s) via a GPCR. Structural information about GPCRs was very limited until 2007, and papers describing new GPCR structures and previously unseen conformational states have dramatically increased in the past few years. In this online special, we present a selection of recently published Nature papers that involve the structures of various GPCRs. Understanding the conformational changes that occur in these proteins when a ligand binds to and activates the receptor should facilitate the development of potential drugs with fewer side effects and more favorable pharmacological properties. ▼ more       Specials - Outlook: Diabetes     About 350 million people — 5% of the world's population — are afflicted by either type 1 diabetes, an autoimmune disorder, or type 2 diabetes, largely linked to lifestyle. Nature Outlook: Diabetes examines the latest research into the causes, therapy, prevention and impact of these devastating diseases. ▼ more       Earth & Environmental Sciences More Earth & Environmental sciences ▼   Earth-like sand fluxes on Mars   Data from the Mars Reconnaissance Orbiter have been used to measure the migration of sand ripples across the Nili Patera dune field in the martian southern hemisphere. The dunes move surprisingly large volumes of sand, equivalent to those seen in extreme desert conditions on Earth.                   Frontiers in Electronic Materials: Correlation Effects and Memristive Phenomena June 17-20, 2012 • Aachen, Germany This conference will bring together leaders in the field to discuss breakthroughs and challenges in fundamental research as well as prospects for future applications. Early booking deadline: April 1, 2012 Poster submissions to be included in the abstract book must be received by April 20, 2012. Register today!                 Earth & Environmental Sciences More Earth & Environmental sciences ▼   Recent Northern Hemisphere tropical expansion primarily driven by black carbon and tropospheric ozone   The tropical climate zone has been expanding for several decades. Allen et al. report that recent increases in black carbon and tropospheric ozone are the most likely causes of expansion into the Northern Hemisphere, with greenhouse gasses a secondary influence.       Biological Sciences More Biological sciences ▼   Extended leaf phenology and the autumn niche in deciduous forest invasions   This study of 73 shrub and vine species growing in the understory in deciduous forests in the eastern United States shows that non-native species have an autumn growing season that is on average 4 weeks longer than that of natives. The invasive species may be driving a seasonal redistribution of forest productivity to rival climate change in its impact on forest processes.       Podcast & Video     In this week's podcast: the transits of Venus, paralysed patients move a robotic arm with their thoughts, and 'superflares'. Plus, the best of the rest from this week's Nature.     In this week's video: Cathy Hutchinson has been unable to move her arms or legs for 15 years. But using the most advanced brain-machine interface ever developed, she can steer a robotic arm towards a bottle and drink her morning coffee. See how Cathy does it and hear from the team behind this pioneering clinical trial.         Special - G protein-coupled receptorsFree Access ▲top               News & Views                   Structural biology: How opioid drugs bind to receptors ▶     Marta Filizola & Lakshmi A. Devi             Articles                   Crystal structure of the µ-opioid receptor bound to a morphinan antagonist ▶     Aashish Manglik, Andrew C. Kruse, Tong Sun Kobilka, Foon Sun Thian, Jesper M. Mathiesen et al.             Structure of the human κ-opioid receptor in complex with JDTic ▶     Huixian Wu, Daniel Wacker, Mauro Mileni, Vsevolod Katritch, Gye Won Han et al.             Letters                   Structure of the nociceptin/orphanin FQ receptor in complex with a peptide mimetic ▶     Aaron A. Thompson, Wei Liu, Eugene Chun, Vsevolod Katritch, Huixian Wu et al.             Structure of the δ-opioid receptor bound to naltrindole ▶     Sébastien Granier, Aashish Manglik, Andrew C. Kruse, Tong Sun Kobilka, Foon Sun Thian et al.               News & Comment Read daily news coverage▶ ▲top             THIS WEEK           Editorials                   Misplaced childhood ▶     The US National Institutes of Health should rethink plans to limit a nationwide study of children. It must not miss a rare opportunity to probe the causes of childhood diseases.             Needless conflict ▶     Independent experts should be kept from undue suspicion as well as undue influence.             Honest opinions ▶     Proposals for a UK law on defamation highlight the power of scientific protest.             World View                   Reach out to defend evolution ▶     Creationists seize on any perceived gaps in our knowledge of evolutionary processes. But scientists can and should fight back, says Russell Garwood.             Seven Days                   Seven days: 11–17 May 2012 ▶     The week in science: Scientific journals to be protected in UK libel reform; Mars rover awakens; and the Global Fund emerges from a fund-raising crisis.           NEWS IN FOCUS           Child-study turmoil leaves bitter taste ▶     Frustration mounts as ambitious US project is scaled back.             Plagiarism charge for Romanian minister ▶     Scandal adds to fears that country's research reform is in peril.             Messages from the early Universe ▶     Bright and brief, γ-ray bursts hold clues to cosmic history.             Malaria surge feared ▶     The WHO releases action plan to tackle the spread of insecticide-resistant mosquitoes.             EU agencies accused of conflicts of interest ▶     European Parliament reprimands food advisory body for industry links.             Go West, young Russian ▶     President Putin to back scheme for students to study abroad.             Features                   Rise of the coyote: The new top dog ▶     Shape-shifting coyotes have evolved to take advantage of a landscape transformed by people. Scientists are now discovering just how wily the creatures are.             Replication studies: Bad copy ▶     In the wake of high-profile controversies, psychologists are facing up to problems with replication.           COMMENT           Science policy: Beyond the great and good ▶     Chief scientific advisers need better support and networks to ensure that science advice to governments is robust, say Robert Doubleday and James Wilsdon.             Transit of Venus: Last chance to see ▶     The June 2012 transit of Venus across the Sun offers an opportunity to check our methods for spotting distant planets crossing far-away stars, says Jay M. Pasachoff.             Books and Arts                   Astronomy: On the track of the transit ▶     Owen Gingerich enjoys two histories of the expeditions that aimed to measure the passage of Venus across the face of the Sun.             Biology: Mammary chronicles ▶     Josie Glausiusz celebrates an environmental history of the human breast.             Books in brief ▶             Q&A: Soundscape explorer ▶     Bioacoustician Bernie Krause has travelled the world for decades to gather animal sounds for his Wild Sanctuary archive (www.wildsanctuary.com). Following the release of his book about this work, The Great Animal Orchestra, he talks about the calls of the wild.             Correspondence                   Particle physics: Don't let furore over neutrinos blur results Tommy Ohlsson | Environment: Control electronic waste in India Govindasamy Agoramoorthy & Chiranjib Chakraborty | Ecology: Preserve Brazil's aquatic biodiversity Jean R. S. Vitule | Drug discovery: In defence of the animal model Richard M. Baldarelli | Sociology: The social sciences are already relevant Frank J. van Rijnsoever           Corrections                   Correction ▶             Correction ▶             Correction ▶                 Biological Sciences ▲top             RESEARCH           Latest Online                   Peroxiredoxins are conserved markers of circadian rhythms ▶     Rachel S. Edgar, Edward W. Green, Yuwei Zhao, Gerben van Ooijen, Maria Olmedo et al.     Daily oxidation–reduction cycles of peroxiredoxin proteins are shown to be conserved in all domains of life, including Bacteria, Archaea and Eukaryota.             NPR3 and NPR4 are receptors for the immune signal salicylic acid in plants ▶     Zheng Qing Fu, Shunping Yan, Abdelaty Saleh, Wei Wang, James Ruble et al.     Plant resistance to pathogen challenge is thought to be mediated through salicylic acid (SA) signalling; here NPR3 and NPR4, paralogues of the transcription cofactor NPR1, are identified as receptors of SA.             The landscape of cancer genes and mutational processes in breast cancer ▶     Philip J. Stephens, Patrick S. Tarpey, Helen Davies, Peter Van Loo, Chris Greenman et al.     A study of breast cancers shows that the number of somatic mutations in each varies markedly and is strongly correlated with age at diagnosis and cancer histological grade.             Butterfly genome reveals promiscuous exchange of mimicry adaptations among species ▶     The Heliconius Genome Consortium     Sequencing of the genome of the butterfly Heliconius melpomene shows that closely related Heliconius species exchange protective colour-pattern genes promiscuously.             Apolipoprotein E controls cerebrovascular integrity via cyclophilin A ▶     Robert D. Bell, Ethan A. Winkler, Itender Singh, Abhay P. Sagare, Rashid Deane et al.     The APOE4-mediated proinflammatory pathway is shown to initiate blood–brain barrier breakdown and resulting neurodegeneration in transgenic mice.             PPAR-γ is a major driver of the accumulation and phenotype of adipose tissue Treg cells ▶     Daniela Cipolletta, Markus Feuerer, Amy Li, Nozomu Kamei, Jongsoon Lee et al.     T regulatory (Treg) cells in visceral adipose tissue express high levels of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)-γ, and fat-specific adaptation of Treg cells is dependent on PPAR-γ.             Heart repair by reprogramming non-myocytes with cardiac transcription factors ▶     Kunhua Song, Young-Jae Nam, Xiang Luo, Xiaoxia Qi, Wei Tan et al.     A combination of four transcription factors, GATA4, HAND2, MEF2C and TBX5, can reprogram fibroblasts into cardiac-like myocytes in vitro and in vivo; expression of these factors ameliorated cardiac function in mice that had suffered myocardial infarction.             Fluoride ion encapsulation by Mg2+ ions and phosphates in a fluoride riboswitch ▶     Aiming Ren, Kanagalaghatta R. Rajashankar & Dinshaw J. Patel     A riboswitch that binds fluoride was identified recently, which is surprising because both RNA and fluoride are negatively charged; here it is shown that the fluoride ion is coordinated to three positively charged magnesium ions, which are further encased in a negatively charged shell of RNA backbone phosphates and water molecules.             Evolution of the chalcone-isomerase fold from fatty-acid binding to stereospecific catalysis ▶     Micheline N. Ngaki, Gordon V. Louie, Ryan N. Philippe, Gerard Manning, Florence Pojer et al.     The diffusion limited stereospecific enzyme chalcone isomerase represents the adaptive evolution of a catalytically perfected enzyme from non-catalytic, fatty-acid-binding proteins (FAPs) with contemporary roles in plant fatty-acid metabolism as evidenced by altered fatty acid content and marked reproductive defects in Arabidopsis thaliana plants bearing FAP knockouts.             α2δ expression sets presynaptic calcium channel abundance and release probability ▶     Michael B. Hoppa, Beatrice Lana, Wojciech Margas, Annette C. Dolphin & Timothy A. Ryan     The voltage-gated calcium channel protein subunit α2δ is shown to control both the abundance of voltage-gated calcium channels and their coupling to the vesicular release of neurotransmitters into the synapse; because the α2δ family is a known target of potent analgesics, this study offers a new link between basic synaptic physiology and pain research in the clinic.             Recurrent network activity drives striatal synaptogenesis ▶     Yevgenia Kozorovitskiy, Arpiar Saunders, Caroline A. Johnson, Bradford B. Lowell & Bernardo L. Sabatini     Neurotransmitter release and activity are modulated in the striatum of mice to demonstrate that the balance of activity within the two antagonistic, inhibitory pathways co-mingled in this nucleus regulates excitatory innervation of the basal ganglia during development.             Compartmentalized calcium dynamics in a C. elegans interneuron encode head movement ▶     Michael Hendricks, Heonick Ha, Nicolas Maffey & Yun Zhang     Subcellular compartmentalization established by mobilization of intracellular calcium stores in RIA interneurons provides a means of self-motion monitoring and a cellular basis for integrating sensory and motor signals in nematodes’ brains.             Genetic recombination is directed away from functional genomic elements in mice ▶     Kevin Brick, Fatima Smagulova, Pavel Khil, R. Daniel Camerini-Otero & Galina V. Petukhova     Comparison of Prdm9−/− and wild-type mice reveals a role for the PRDM9 protein in directing the recombination machinery away from important genomic regions.             Articles and Letters                   Crystal structure of the µ-opioid receptor bound to a morphinan antagonist ▶     Aashish Manglik, Andrew C. Kruse, Tong Sun Kobilka, Foon Sun Thian, Jesper M. Mathiesen et al.     The crystal structure of the mouse μ-opioid receptor bound to an antagonist is described, with possible implications for the future development of analgesics.             Structure of the human κ-opioid receptor in complex with JDTic ▶     Huixian Wu, Daniel Wacker, Mauro Mileni, Vsevolod Katritch, Gye Won Han et al.     The crystal structure of the human κ-opioid receptor in complex with an antagonist, JDTic, is determined, with potential importance for the design of new therapeutic agents.             Cardiac angiogenic imbalance leads to peripartum cardiomyopathy ▶     Ian S. Patten, Sarosh Rana, Sajid Shahul, Glenn C. Rowe, Cholsoon Jang et al.     Evidence from mice and humans indicates that peripartum cardiomyopathy (PPCM) is a vascular disease caused by excessive anti-angiogenic signalling in the peripartum period of pregnancy and that pre-eclampsia and multiple gestation are important risk factors for the development of PPCM.             Extended leaf phenology and the autumn niche in deciduous forest invasions ▶     Jason D. Fridley     A 3-year study of 73 deciduous understory species from the Eastern USA shows that non-native species retain leaf function 4 weeks longer into autumn than natives, which may be shifting seasonal patterns of forest carbon and nutrient dynamics.             KCTD13 is a major driver of mirrored neuroanatomical phenotypes of the 16p11.2 copy number variant ▶     Christelle Golzio, Jason Willer, Michael E. Talkowski, Edwin C. Oh, Yu Taniguchi et al.     Overexpression of all 29 human transcripts of a region of the 16p11.2 chromosome in zebrafish embryos identifies KCTD13 as the message inducing the microcephaly phenotype associated with 16p11.2 duplication, whereas its suppression yields the macrocephalic phenotype associated with the reciprocal deletion, suggesting that KCTD13 is a major driver for the neurodevelopmental phenotypes associated with the 16p11.2 copy number variants.             Restoration of grasp following paralysis through brain-controlled stimulation of muscles ▶     C. Ethier, E. R. Oby, M. J. Bauman & L. E. Miller     A functional electrical stimulation system in primates that is controlled by recordings made from microelectrodes permanently implanted in the brain can be used to control the intensity of stimulation of muscles that are temporarily paralysed by pharmacological motor nerve blockade, thereby restoring voluntary control of the affected muscles; this is a major advance towards similar restoration of hand function in human patients with spinal cord injury.             Reach and grasp by people with tetraplegia using a neurally controlled robotic arm ▶     Leigh R. Hochberg, Daniel Bacher, Beata Jarosiewicz, Nicolas Y. Masse, John D. Simeral et al.     Two people with long-standing tetraplegia use neural interface system-based control of a robotic arm to perform three-dimensional reach and grasp movements.             Topological domains in mammalian genomes identified by analysis of chromatin interactions ▶     Jesse R. Dixon, Siddarth Selvaraj, Feng Yue, Audrey Kim, Yan Li et al.     The three-dimensional organization of the human and mouse genomes in embryonic stem cells and terminally differentiated cell types is investigated, revealing that large, megabase-sized chromatin interaction domains are a pervasive and conserved structural feature of genome organization.             Spatial partitioning of the regulatory landscape of the X-inactivation centre ▶     Elphège P. Nora, Bryan R. Lajoie, Edda G. Schulz, Luca Giorgetti, Ikuhiro Okamoto et al.     High-order chromatin folding in topologically associating domains has a critical role in proper long-range transcriptional control around the Xist locus, and presumably throughout the genome.             RNF12 initiates X-chromosome inactivation by targeting REX1 for degradation ▶     Cristina Gontan, Eskeatnaf Mulugeta Achame, Jeroen Demmers, Tahsin Stefan Barakat, Eveline Rentmeester et al.     The pluripotency factor REX1 is a key target of RNF12 during X-chromosome inactivation; degradation of REX1 by RNF12 leads to relief of its inhibitory action on X-chromosome inactivation.             A PPARγ–FGF1 axis is required for adaptive adipose remodelling and metabolic homeostasis ▶     Johan W. Jonker, Jae Myoung Suh, Annette R. Atkins, Maryam Ahmadian, Pingping Li et al.     PPARγ induces fibroblast growth factor 1 to remodel visceral adipose tissue in response to a high-fat diet to maintain metabolic homeostasis.             Structure of the nociceptin/orphanin FQ receptor in complex with a peptide mimetic ▶     Aaron A. Thompson, Wei Liu, Eugene Chun, Vsevolod Katritch, Huixian Wu et al.     The crystal structure of the human nociceptin/orphanin FQ peptide receptor in complex with the peptide mimetic antagonist compound-24 is determined, with potential importance for the development of new therapeutic agents.             Structure of the δ-opioid receptor bound to naltrindole ▶     Sébastien Granier, Aashish Manglik, Andrew C. Kruse, Tong Sun Kobilka, Foon Sun Thian et al.     The X-ray crystal structure of the mouse δ-opioid receptor in complex with the subtype-selective antagonist naltrindole is reported.             News & Views                   Structural biology: How opioid drugs bind to receptors ▶     Marta Filizola & Lakshmi A. Devi             Neuroscience: Brain-controlled robot grabs attention ▶     Andrew Jackson             Genetics: Fish heads and human disease ▶     Dheeraj Malhotra & Jonathan Sebat             Addendum                   Addendum: Verbal and non-verbal intelligence changes in the teenage brain ▶     Sue Ramsden, Fiona M. Richardson, Goulven Josse, Michael S. C. Thomas, Caroline Ellis et al.             Research Highlights                   Cancer: Environment of chemo success | Environmental health: Less biodiversity, more allergies | Neuroscience: Anti-seizure drug boosts memory | Biomaterials: High-voltage plant proteins | Photonics: Solar panel in the eye | Anthropology: Ancient Mayan wall calendar | Neuroscience: The neural core of consciousness         NEWS & COMMENT           Misplaced childhood | Needless conflict | Reach out to defend evolution | Child-study turmoil leaves bitter taste | Malaria surge feared | EU agencies accused of conflicts of interest | Rise of the coyote: The new top dog | Replication studies: Bad copy | Biology: Mammary chronicles | Q&A: Soundscape explorer | Ecology: Preserve Brazil's aquatic biodiversity Jean R. S. Vitule | Drug discovery: In defence of the animal model Richard M. Baldarelli             More Biological Sciences ▶                         THE TARA OCEANS EXPEDITION A Special Podcast In a 2.5 year journey across the globe's oceans, the TARA OCEANS expedition has collected unique information on the biodiversity and biogeography of the marine ecosystem. Project co-director Eric Karsenti shares his excitement about this exceptional human and scientific adventure and explains how researchers will analyze the data to better understand life on our planet. Listen to our FREE podcast now!               Chemical Sciences ▲top             RESEARCH           Latest Online                   Peroxiredoxins are conserved markers of circadian rhythms ▶     Rachel S. Edgar, Edward W. Green, Yuwei Zhao, Gerben van Ooijen, Maria Olmedo et al.     Daily oxidation–reduction cycles of peroxiredoxin proteins are shown to be conserved in all domains of life, including Bacteria, Archaea and Eukaryota.             NPR3 and NPR4 are receptors for the immune signal salicylic acid in plants ▶     Zheng Qing Fu, Shunping Yan, Abdelaty Saleh, Wei Wang, James Ruble et al.     Plant resistance to pathogen challenge is thought to be mediated through salicylic acid (SA) signalling; here NPR3 and NPR4, paralogues of the transcription cofactor NPR1, are identified as receptors of SA.             Fluoride ion encapsulation by Mg2+ ions and phosphates in a fluoride riboswitch ▶     Aiming Ren, Kanagalaghatta R. Rajashankar & Dinshaw J. Patel     A riboswitch that binds fluoride was identified recently, which is surprising because both RNA and fluoride are negatively charged; here it is shown that the fluoride ion is coordinated to three positively charged magnesium ions, which are further encased in a negatively charged shell of RNA backbone phosphates and water molecules.             Evolution of the chalcone-isomerase fold from fatty-acid binding to stereospecific catalysis ▶     Micheline N. Ngaki, Gordon V. Louie, Ryan N. Philippe, Gerard Manning, Florence Pojer et al.     The diffusion limited stereospecific enzyme chalcone isomerase represents the adaptive evolution of a catalytically perfected enzyme from non-catalytic, fatty-acid-binding proteins (FAPs) with contemporary roles in plant fatty-acid metabolism as evidenced by altered fatty acid content and marked reproductive defects in Arabidopsis thaliana plants bearing FAP knockouts.             Articles and Letters                   Crystal structure of the µ-opioid receptor bound to a morphinan antagonist ▶     Aashish Manglik, Andrew C. Kruse, Tong Sun Kobilka, Foon Sun Thian, Jesper M. Mathiesen et al.     The crystal structure of the mouse μ-opioid receptor bound to an antagonist is described, with possible implications for the future development of analgesics.             Resolving the time when an electron exits a tunnelling barrier ▶     Dror Shafir, Hadas Soifer, Barry D. Bruner, Michal Dagan, Yann Mairesse et al.     A method of laser-induced recollision permits measurement with attosecond resolution of the times at which the electron leaves the tunnelling barrier and discriminates between the ionization times of two carbon dioxide orbitals.             Light-induced liquid crystallinity ▶     Tamas Kosa, Ludmila Sukhomlinova, Linli Su, Bahman Taheri, Timothy J. White et al.     A new class of liquid crystals is reported that undergoes light-induced ordering and order-increasing phase transitions; possible applications include ophthalmic devices, such as variable transmission sunglasses.             A PPARγ–FGF1 axis is required for adaptive adipose remodelling and metabolic homeostasis ▶     Johan W. Jonker, Jae Myoung Suh, Annette R. Atkins, Maryam Ahmadian, Pingping Li et al.     PPARγ induces fibroblast growth factor 1 to remodel visceral adipose tissue in response to a high-fat diet to maintain metabolic homeostasis.             Structure of the nociceptin/orphanin FQ receptor in complex with a peptide mimetic ▶     Aaron A. Thompson, Wei Liu, Eugene Chun, Vsevolod Katritch, Huixian Wu et al.     The crystal structure of the human nociceptin/orphanin FQ peptide receptor in complex with the peptide mimetic antagonist compound-24 is determined, with potential importance for the development of new therapeutic agents.             Structure of the δ-opioid receptor bound to naltrindole ▶     Sébastien Granier, Aashish Manglik, Andrew C. Kruse, Tong Sun Kobilka, Foon Sun Thian et al.     The X-ray crystal structure of the mouse δ-opioid receptor in complex with the subtype-selective antagonist naltrindole is reported.             News & Views                   Atomic physics: Electrons get real ▶     Manfred Lein             Structural biology: How opioid drugs bind to receptors ▶     Marta Filizola & Lakshmi A. Devi           NEWS & COMMENT           Biology: Mammary chronicles             More Chemical Sciences ▶               Physical Sciences ▲top             RESEARCH           Latest Online                   Astrophysics: Startling superflares ▶     Bradley E. Schaefer             Superflares on solar-type stars ▶     Hiroyuki Maehara, Takuya Shibayama, Shota Notsu, Yuta Notsu, Takashi Nagao et al.     Observations of superflares on solar-type stars indicate that they are associated with much larger starspots than appear on the Sun, occur more frequently on rapidly rotating stars and, contrary to a previous proposal, are not frequently associated with hot Jupiters.             Genetic recombination is directed away from functional genomic elements in mice ▶     Kevin Brick, Fatima Smagulova, Pavel Khil, R. Daniel Camerini-Otero & Galina V. Petukhova     Comparison of Prdm9−/− and wild-type mice reveals a role for the PRDM9 protein in directing the recombination machinery away from important genomic regions.             Articles and Letters                   Resolving the time when an electron exits a tunnelling barrier ▶     Dror Shafir, Hadas Soifer, Barry D. Bruner, Michal Dagan, Yann Mairesse et al.     A method of laser-induced recollision permits measurement with attosecond resolution of the times at which the electron leaves the tunnelling barrier and discriminates between the ionization times of two carbon dioxide orbitals.             Light-induced liquid crystallinity ▶     Tamas Kosa, Ludmila Sukhomlinova, Linli Su, Bahman Taheri, Timothy J. White et al.     A new class of liquid crystals is reported that undergoes light-induced ordering and order-increasing phase transitions; possible applications include ophthalmic devices, such as variable transmission sunglasses.             Recent Northern Hemisphere tropical expansion primarily driven by black carbon and tropospheric ozone ▶     Robert J. Allen, Steven C. Sherwood, Joel R. Norris & Charles S. Zender     The primary drivers of the Northern Hemisphere expansion of the tropical climate zone over the past several decades are shown to be the recent increases in black carbon aerosols and tropospheric ozone rather than in greenhouse gases, which contribute to a lesser extent.             Thermal and electrical conductivity of iron at Earth’s core conditions ▶     Monica Pozzo, Chris Davies, David Gubbins & Dario Alfè     First principles calculations of the thermal and electrical conductivities of liquid iron mixtures under Earth's core conditions suggest a relatively high adiabatic heat flux of 15 to16 terawatts at the core–mantle boundary, indicating that the top of the core must be thermally stratified.             Restoration of grasp following paralysis through brain-controlled stimulation of muscles ▶     C. Ethier, E. R. Oby, M. J. Bauman & L. E. Miller     A functional electrical stimulation system in primates that is controlled by recordings made from microelectrodes permanently implanted in the brain can be used to control the intensity of stimulation of muscles that are temporarily paralysed by pharmacological motor nerve blockade, thereby restoring voluntary control of the affected muscles; this is a major advance towards similar restoration of hand function in human patients with spinal cord injury.             Reach and grasp by people with tetraplegia using a neurally controlled robotic arm ▶     Leigh R. Hochberg, Daniel Bacher, Beata Jarosiewicz, Nicolas Y. Masse, John D. Simeral et al.     Two people with long-standing tetraplegia use neural interface system-based control of a robotic arm to perform three-dimensional reach and grasp movements.             News & Views                   Atomic physics: Electrons get real ▶     Manfred Lein             Neuroscience: Brain-controlled robot grabs attention ▶     Andrew Jackson             Earth science: Geomagnetism under scrutiny ▶     Bruce Buffett             Astrophysics: Startling superflares ▶     Bradley E. Schaefer             Research Highlights                   Planetary science: Planet-like asteroid | Photonics: Solar panel in the eye | Astronomy: Exoplanet signals ring true         NEWS & COMMENT           Plagiarism charge for Romanian minister | Messages from the early Universe | Transit of Venus: Last chance to see | Astronomy: On the track of the transit | Particle physics: Don't let furore over neutrinos blur results Tommy Ohlsson | Environment: Control electronic waste in India Govindasamy Agoramoorthy & Chiranjib Chakraborty           CAREERS           Turning point: Mark Lawrence             More Physical Sciences ▶               Earth & Environmental Sciences ▲top             RESEARCH           Articles and Letters                   Earth-like sand fluxes on Mars ▶     N. T. Bridges, F. Ayoub, J-P. Avouac, S. Leprince, A. Lucas et al.     Satellite images of a Martian dune field reveal unexpectedly high sand fluxes, suggesting rates of landscape modification similar to those on Earth.             Recent Northern Hemisphere tropical expansion primarily driven by black carbon and tropospheric ozone ▶     Robert J. Allen, Steven C. Sherwood, Joel R. Norris & Charles S. Zender     The primary drivers of the Northern Hemisphere expansion of the tropical climate zone over the past several decades are shown to be the recent increases in black carbon aerosols and tropospheric ozone rather than in greenhouse gases, which contribute to a lesser extent.             Thermal and electrical conductivity of iron at Earth’s core conditions ▶     Monica Pozzo, Chris Davies, David Gubbins & Dario Alfè     First principles calculations of the thermal and electrical conductivities of liquid iron mixtures under Earth's core conditions suggest a relatively high adiabatic heat flux of 15 to16 terawatts at the core–mantle boundary, indicating that the top of the core must be thermally stratified.             News & Views                   Planetary science: Martian sand blowing in the wind ▶     Jasper Kok             Earth science: Geomagnetism under scrutiny ▶     Bruce Buffett             Research Highlights                   Planetary science: Planet-like asteroid | Environmental health: Less biodiversity, more allergies         NEWS & COMMENT           Transit of Venus: Last chance to see | Environment: Control electronic waste in India Govindasamy Agoramoorthy & Chiranjib Chakraborty           CAREERS           Turning point: Mark Lawrence             More Earth & Environmental Sciences ▶               Special - Nature Outlook: DiabetesFree Access ▲top               Diabetes ▶     Herb Brody             Diabetes in numbers ▶     The number of people living with, and dying of, diabetes across the world is shocking: 90 million Chinese live with diabetes and 1.3 million died in 2011; 23% of Qatari adults have developed diabetes. Here we chart the extent of the global epidemic and present some of the implications for national governments by Tony Scully.              Immunomodulators: Cell savers ▶     In type 1 diabetes, the immune system goes haywire and depletes insulin-producing cells. Drugs that interfere with this process could one day reverse the disease's course.              Medical devices: Managed by machine ▶     Artificial pancreases promise to take the decision-making — and human mistakes — out of managing type 1 diabetes.              Perspective: Rethink the immune connection ▶     Recent research suggests that the fight against type 1 diabetes is focusing too narrowly on the adaptive immune system, says Carla Greenbaum.              Pathology: Cause and effect ▶     Decades of study into the causes of diabetes have produced no definitive answers.              Microbiome: The critters within ▶     Your gut microflora might be aiding and abetting diabetes.              Public health: India's diabetes time bomb ▶     Epigenetics and lifestyle are conspiring to inflict a massive epidemic of type 2 diabetes in the subcontinent.              Perspective: Testing failures ▶     Promising drugs to treat diabetes stumble in the latter stages of clinical testing. Thomas Mandrup-Poulsen explains why — and how to fix it.              Prevention: Nipped in the bud ▶     While type 1 diabetes might be promising ground for a vaccine, the most effective way to avoid type 2 remains good old-fashioned diet and exercise.          Sponsors                     Nature Reviews Cancer & Nature Reviews Immunology FOCUS ON TUMOUR IMMUNOLOGY & IMMUNOTHERAPY Access the Focus online for FREE until end of September 2012: www.nature.com/reviews/focus/tumourimmunology Produced with support from Boehringer Ingelheim               Careers & Jobs ▲top               Going digital ▶     Creating electronic textbooks requires ingenuity, teamwork and multimedia savvy.                   Turning point: Mark Lawrence ▶     After launching a career in Germany, sustainability institute director aims to help society by reducing pollution.                   Careers related news & comment                   EU agencies accused of conflicts of interest | Go West, young Russian | Replication studies: Bad copy             naturejobs.com Science jobs of the week       Research Associate     UMass Medical School - Worcester            Postdoctoral Fellows - Lung Regenerative Engineering     Temple University            Computational Biology faculty     Brigham & Women's Hospital            Postdoctoral Research Assistant     University of Dundee          No matter what your career stage, student, postdoc or senior scientist, you will find articles on naturejobs.com to help guide you in your science career. 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