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Journal Cover   Science
  [SJR: 12.465]   [H-I: 801]   [2225 followers]  Follow
   Full-text available via subscription Subscription journal
   ISSN (Print) 0036-8075 - ISSN (Online) 1095-9203
   Published by American Association for the Advancement of Science (AAAS) Homepage  [5 journals]
  • [Perspective] A tree of the human brain
    • Authors: Sten Linnarsson
      Abstract: Every cell of your body was generated by cell division, forming a lineage tree that goes back to the fertilized egg. Mutations are introduced by errors in DNA replication at every cell division, as well as by mutational processes that operate continuously, such as exposure to ultraviolet light. As a consequence, every cell may have its own unique genome, with potentially distinct gains and losses of function. Furthermore, these mutations create a record of the developmental ancestry of each cell, which can be used to reconstruct their lineage tree. Now, on page 94 of this issue, Lodato et al. use single-cell whole-genome sequencing to show these processes at work in the human brain (1). This is important because many unresolved questions in human biology and medicine are in fact questions about the human cell lineage tree in development and disease (2). Charles Darwin famously drew the first phylogenetic tree in 1837. This was only a month after he had started his first notebook on evolution, but the idea had already gelled in his mind that all species are linked like the branches on a tree. A few years later, around the time he was completing On the Origin of Species, a similarly remarkable insight was forming among a small group of scientists in Germany. Theodor Schwann and Matthias Schleiden had realized that both plants and animals are made of nothing but cells, but it was Robert Remak who showed that new cells arise through binary fission. These insights lead to the conclusion that every individual is also a tree—a cell lineage tree. Author: Sten Linnarsson
      Keywords: Neuroscience
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad2792
  • [Perspective] How stable are food webs during a mass extinction?
    • Authors: Charles R. Marshall
      Abstract: As we confront the reality of the ongoing human-driven mass extinction (1), attention often focuses on the response of individual species to environmental change. However, species survival also depends on other species in the food web: Changing population numbers or extinction of one species can propagate through the food web to cause further perturbation or extinction. Although this has long been appreciated (2), it is hard to test predictions of how food webs of living ecosystems will be affected by disturbance. The fossil record provides a window into how past food webs have responded to mass extinction. On page 90 of this issue, Roopnarine and Angielczyk (3) assess food web stability of the remarkably well-preserved terrestrial communities of the Karoo Basin in South Africa across the largest past mass extinction, the Permian-Triassic event (∼252 million years ago). Author: Charles R. Marshall
      Keywords: Ecology/Paleontology
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad2729
  • [Perspective] Eyeing up a Jupiter-like exoplanet
    • Authors: Dimitri Mawet
      Abstract: With thousands of exoplanets having been discovered over the past 20 years, the solar system is recognized as presenting just one example among a mind-boggling variety of system architectures: from circumbinary exoplanets (1), systems with tightly packed inner planets (2), water-worlds (3), potential Earth twins (4), super-Earths (5), sub- and super-Neptunes (6), evaporating comet-like planets (7), giant rings (8), and hazy hot Jupiters all the way to extremely long-period lonely massive objects looking more like failed stars than giant planets. So far, the vast majority of these planetary systems have been discovered indirectly by techniques looking at tiny variations in their host star's motion and/or brightness. These techniques have limited remote-sensing capabilities, yet have ushered in an entirely new branch of astrophysics called comparative exoplanetology, putting the solar system and its planets into a universal perspective. On page 64 of this issue, Macintosh et al. (9) present the discovery of a young giant exoplanet with the Gemini Planet Imager (GPI) and a technique called high-contrast imaging. Beyond taking striking pictures (see the figure), the technique promises to yield the most detailed measurements of whole distant planetary systems, including spectroscopy of planet atmospheres and time-resolved astrometry of their orbital motion. Author: Dimitri Mawet
      Keywords: Planetary Science
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad0904
  • [Policy Forum] The IPCC at a crossroads: Opportunities for reform
    • Authors: Carlo Carraro
      Abstract: The Intergovernmental Panel on Climate Change (IPCC) has proven its value as an institution for large-scale scientific collaboration to synthesize and assess large volumes of climate research for use by policy-makers, as well as for establishing credibility of findings among diverse national governments. But the IPCC has received considerable criticism of both its substance and process. The new IPCC leadership to be elected in October could help guide the IPCC to a clear, shared understanding of future objectives and could shape procedural reforms. We identify key opportunities for reform by addressing two related questions: Is the IPCC doing the right things? Is the IPCC doing things right?
      Authors : Carlo Carraro, Ottmar Edenhofer, Christian Flachsland, Charles Kolstad, Robert Stavins, Robert Stowe
      Keywords: Climate Change
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac4419
  • [Policy Forum] Added value from IPCC approval sessions
    • Authors: Christopher B. Field
      Abstract: Approval sessions of the Intergovernmental Panel on Climate Change (IPCC) generate broadly shared ownership of scientific knowledge on climate change—a key contribution to the influence of IPCC reports (1, 2). Yet several recent essays have highlighted weaknesses of the approval process (3, 4). We draw on our experience cochairing Working Group II to provide some balance and to characterize important strengths. Although the governmental approval process can be cumbersome, sleep-depriving, and tinged with risk of political influence (5), successful approval sessions sharpen policy-relevant findings to make them more clear and useful (6).
      Authors : Christopher B. Field, Vicente R. Barros
      Keywords: Climate Change
      PubDate: 2015-10-02
      DOI: 10.1126/science.aaa8976
  • [Letter] Funding dreams
    • PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.30
  • [Letter] Submit Now: Political Science
    • PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.31
  • [Perspective] Safer fuels by integrating polymer theory into design
    • Authors: Michael Jaffe
      Abstract: For the past few decades, the civil aviation industry has increased its efforts to prevent fuel fires initiated by aviation crashes by improving fuel safety and handling. These fires are estimated to be responsible for 40% of fatalities, corresponding to approximately 500 to 1000 deaths that could be minimized annually with improved fire-safe fuel (1). Fuel fires are also increasingly becoming a hazard to homeland security, as seen in the example of the September 11, 2001 attacks on the World Trade Centers (2). The mist is much more flammable than the liquid, and antimisting kerosene (AMK) interferes with mist formation by incorporating a low concentration (
      Keywords: Polymer Chemistry
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac9827
  • [Perspective] Locking down the core of the pore
    • Authors: Katharine S. Ullman
      Abstract: Nuclear pore complexes (NPCs), first observed by electron microscopy 65 years ago, mediate selective transport of macromolecules between the nucleus and cytoplasm of eukaryotic cells. Although the exact size and protein composition of NPCs can vary between species, these massive and complex machines are highly conserved in their overall organization, which consists of multiple copies of ∼30 nuclear pore proteins, or nucleoporins (Nups), in a symmetrical eightfold radial arrangement. Deciphering the structure of this immense complex has required ongoing multifaceted approaches (1). On page 106 and 56 in this issue, Chug et al. (2) and Stuwe et al. (3), respectively, have employed parallel approaches in very distant species and arrived at remarkably similar and informative structures of an essential subcomplex of the NPC.
      Authors : Katharine S. Ullman, Maureen A. Powers
      Keywords: Structural Biology
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad3797
  • [Feature] The storm king
    • Authors: Eric Hand
      Abstract: A mysterious weather pattern stalks Earth's tropics. Every 30-60 days, something called the Madden-Julian oscillation (MJO) circles the equator, bringing rain and wind wherever it goes. Discovered in 1971, but still not completely understood, the MJO is the biggest driver of tropical weather. It also has large effects on weather outside the tropics, triggering and strengthening hurricanes, monsoons, and heat waves in higher latitudes. This year's powerful El Nino was almost certainly set off by a trifecta of MJO events. Scientists are making progress in understanding this hidden force in weather and climate. Computer models are finally mimicking the MJO, after decades of failure. That is allowing weather forecasters to push their predictions further into the future than ever before, while climate scientists are exploring how the MJO will behave in a warmer world. And after an intense field campaign in the Indian Ocean involving dozens of nations, researchers are starting to answer some of the most fundamental questions of all: Why does the MJO exist, and how does it form? Author: Eric Hand
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.22
  • [In Depth] Have physicists seen the dying flash of dark matter?
    • Authors: Edwin Cartlidge
      Abstract: Dark matter, by definition, can't be seen directly—except perhaps when it dies. For years, scientists have scanned the skies for signals given off by the decay or mutual annihilation of these elusive particles, which make up fully 80% of the matter in the universe. They've seen nothing definitive, but physicists are now reporting a new candidate: a peak in x-ray emission at an energy of 3.5 thousand electron volts (keV). After many inconclusive claims, this one may be testable, they and other researchers say, by an upcoming satellite mission. "The 3.5-keV x-ray signal has a real chance of being definitively confirmed as dark matter in a few years, unlike other putative signals currently on the market," says Jonathan Feng, a particle theorist at the University of California, Irvine. Author: Edwin Cartlidge
      Keywords: Particle Physics
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.20
  • [In Depth] Holland's giant wavemaker has splashy debut
    • Authors: Martin Enserink
      Abstract: On 5 October, Deltares, a research institute in Delft, the Netherlands, will inaugurate a new experimental facility that can produce the largest man-made waves in the world. The Delta Flume, as it's called, is a 300-meter long water-filled trough that's 9.5 meters high and 5 meters wide. It produces waves as high as 4.5 meters that researchers will use to study and improve coastal protection systems. Scientists can also use the flume to study natural processes such as sediment transport along shorelines and the mechanical properties of coastal soils. The flume replaces an older, smaller version that will be retired after 35 years of service. Author: Martin Enserink
      Keywords: Hydraulic Engineering
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.21
  • [Research Article] Architecture of the fungal nuclear pore inner ring
    • Authors: Tobias Stuwe
      Abstract: The nuclear pore complex (NPC) constitutes the sole gateway for bidirectional nucleocytoplasmic transport. We present the reconstitution and interdisciplinary analyses of the ~425-kilodalton inner ring complex (IRC), which forms the central transport channel and diffusion barrier of the NPC, revealing its interaction network and equimolar stoichiometry. The Nsp1•Nup49•Nup57 channel nucleoporin heterotrimer (CNT) attaches to the IRC solely through the adaptor nucleoporin Nic96. The CNT•Nic96 structure reveals that Nic96 functions as an assembly sensor that recognizes the three-dimensional architecture of the CNT, thereby mediating the incorporation of a defined CNT state into the NPC. We propose that the IRC adopts a relatively rigid scaffold that recruits the CNT to primarily form the diffusion barrier of the NPC, rather than enabling channel dilation.
      Authors : Tobias Stuwe, Christopher J. Bley, Karsten Thierbach, Stefan Petrovic, Sandra Schilbach, Daniel J. Mayo, Thibaud Perriches, Emily J. Rundlet, Young E. Jeon, Leslie N. Collins, Ferdinand M. Huber, Daniel H. Lin, Marcin Paduch, Akiko Koide, Vincent Lu, Jessica Fischer, Ed Hurt, Shohei Koide, Anthony A. Kossiakoff, André Hoelz
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac9176
  • [Editors' Choice] Triple threat
    • Authors: Lisa D. Chong
      Abstract: Author: Lisa D. Chong
      Keywords: Antibiotics
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.53-g
  • [Research Article] Genetic determinants of in vivo fitness and diet
           responsiveness in multiple human gut Bacteroides
    • Authors: Meng Wu
      Abstract: Libraries of tens of thousands of transposon mutants generated from each of four human gut Bacteroides strains, two representing the same species, were introduced simultaneously into gnotobiotic mice together with 11 other wild-type strains to generate a 15-member artificial human gut microbiota. Mice received one of two distinct diets monotonously, or both in different ordered sequences. Quantifying the abundance of mutants in different diet contexts allowed gene-level characterization of fitness determinants, niche, stability, and resilience and yielded a prebiotic (arabinoxylan) that allowed targeted manipulation of the community. The approach described is generalizable and should be useful for defining mechanisms critical for sustaining and/or approaches for deliberately reconfiguring the highly adaptive and durable relationship between the human gut microbiota and host in ways that promote wellness.
      Authors : Meng Wu, Nathan P. McNulty, Dmitry A. Rodionov, Matvei S. Khoroshkin, Nicholas W. Griffin, Jiye Cheng, Phil Latreille, Randall A. Kerstetter, Nicolas Terrapon, Bernard Henrissat, Andrei L. Osterman, Jeffrey I. Gordon
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac5992
  • [Editors' Choice] A close look at the catalyst interface
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Water Splitting
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.53-d
  • [Editors' Choice] Oh, what places they'll go
    • Authors: Pamela J. Hines
      Abstract: Author: Pamela J. Hines
      Keywords: Neural Crest
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.53-e
  • [Editors' Choice] The most wanted and most fastidious
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Microbiome
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.53-f
  • [Editors' Choice] Like mother, like father
    • Authors: Sacha Vignieri
      Abstract: Author: Sacha Vignieri
      Keywords: Reproductive Evolution
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.53-a
  • [Editors' Choice] Building a nanowire superconducting qubit
    • Authors: Jelena Stajic
      Abstract: Author: Jelena Stajic
      Keywords: Superconduction
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.53-b
  • [Editors' Choice] GRBs not fatal for life in early universe
    • Authors: Keith T. Smith
      Abstract: Author: Keith T. Smith
      Keywords: Astronomy
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.53-c
  • [This Week in Science] Memory consolidation by gene suppression
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Memory Mechanisms
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-m
  • [This Week in Science] An alternative way of making GABA
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Neurotransmission
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-n
  • [This Week in Science] Increasing the response to TGF-β signals
    • Authors: Wei Wong
      Abstract: Author: Wei Wong
      Keywords: Cell Biology
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-o
  • [This Week in Science] Making better small contacts
    • Authors: Phil Szuromi
      Abstract: Author: Phil Szuromi
      Keywords: Nanoelectronics
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-p
  • [Report] Community stability and selective extinction during the
           Permian-Triassic mass extinction
    • Authors: Peter D. Roopnarine
      Abstract: The fossil record contains exemplars of extreme biodiversity crises. Here, we examined the stability of terrestrial paleocommunities from South Africa during Earth's most severe mass extinction, the Permian-Triassic. We show that stability depended critically on functional diversity and patterns of guild interaction, regardless of species richness. Paleocommunities exhibited less transient instability—relative to model communities with alternative community organization—and significantly greater probabilities of being locally stable during the mass extinction. Functional patterns that have evolved during an ecosystem's history support significantly more stable communities than hypothetical alternatives.
      Authors : Peter D. Roopnarine, Kenneth D. Angielczyk
      PubDate: 2015-10-02
      DOI: 10.1126/science.aab1371
  • [Report] Somatic mutation in single human neurons tracks developmental and
           transcriptional history
    • Authors: Michael A. Lodato
      Abstract: Neurons live for decades in a postmitotic state, their genomes susceptible to DNA damage. Here we survey the landscape of somatic single-nucleotide variants (SNVs) in the human brain. We identified thousands of somatic SNVs by single-cell sequencing of 36 neurons from the cerebral cortex of three normal individuals. Unlike germline and cancer SNVs, which are often caused by errors in DNA replication, neuronal mutations appear to reflect damage during active transcription. Somatic mutations create nested lineage trees, allowing them to be dated relative to developmental landmarks and revealing a polyclonal architecture of the human cerebral cortex. Thus, somatic mutations in the brain represent a durable and ongoing record of neuronal life history, from development through postmitotic function.
      Authors : Michael A. Lodato, Mollie B. Woodworth, Semin Lee, Gilad D. Evrony, Bhaven K. Mehta, Amir Karger, Soohyun Lee, Thomas W. Chittenden, Alissa M. D’Gama, Xuyu Cai, Lovelace J. Luquette, Eunjung Lee, Peter J. Park, Christopher A. Walsh
      PubDate: 2015-10-02
      DOI: 10.1126/science.aab1785
  • [This Week in Science] Diet shapes host and gut microbe fitness
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Gut Microbiota
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-j
  • [This Week in Science] How well does water share its protons?
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Water Structure
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-k
  • [This Week in Science] Individualized neuronal mutations in the human
    • Authors: Pamela J. Hines
      Abstract: Author: Pamela J. Hines
      Keywords: Neurodevelopment
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-l
  • [This Week in Science] Improving gene editing in human T cells
    • Authors: Katrina L. Kelner
      Abstract: Author: Katrina L. Kelner
      Keywords: Genome Editing
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-h
  • [This Week in Science] Transient polymer links are better
    • Authors: Marc S. Lavine
      Abstract: Author: Marc S. Lavine
      Keywords: Polymer Chemistry
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-i
  • [In Depth] Europe's rifts over transgenic crops deepen at key deadline
    • Authors: Tania Rabesandratana
      Abstract: Greece's fiscal problems and a massive refugee crisis have laid bare deep rifts in the European Union (E.U.), leading to bitter policy disputes and the reappearance of border controls eliminated years ago. A quieter rift is deepening on the issue of genetically modified (GM) crops, which many Europeans reject. An E.U. directive that took force in April essentially allowed countries to bypass E.U.-wide, science-based authorizations for these crops and set their own rules. This week marks the deadline for countries to file their first plans to keep GM crops out—an exercise that has brought the fractures between pro- and anti-GM governments into full view. Author: Tania Rabesandratana
      Keywords: Biotechnology
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.18
  • [In Depth] Talking science and God with the pope's new astronomer
    • Authors: Edwin Cartlidge
      Abstract: On 18 September, Pope Francis appointed Jesuit brother Guy Consolmagno, 63, as the new director of the Vatican Observatory, which employs a dozen astronomers to study asteroids, meteorites, extrasolar planets, stellar evolution, and cosmology. The observatory is based at the pope's summer residence south of Rome and operates a 1.8-meter telescope in Arizona. In an interview with Science, Consolmagno discussed why the Vatican does astronomy, the observatory's contributions to science, and what he hopes to achieve as director. He also discussed the relation between religion and science. God doesn't get in the way of doing good astronomy, Consolmagno said: "Just the opposite. He is the reason we do astronomy." Author: Edwin Cartlidge
      Keywords: Q&A
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.17
  • [Report] Multiple repressive mechanisms in the hippocampus during memory
    • Authors: Jun Cho
      Abstract: Memory stabilization after learning requires translational and transcriptional regulations in the brain, yet the temporal molecular changes that occur after learning have not been explored at the genomic scale. We used ribosome profiling and RNA sequencing to quantify the translational status and transcript levels in the mouse hippocampus after contextual fear conditioning. We revealed three types of repressive regulations: translational suppression of ribosomal protein-coding genes in the hippocampus, learning-induced early translational repression of specific genes, and late persistent suppression of a subset of genes via inhibition of estrogen receptor 1 (ESR1/ERα) signaling. In behavioral analyses, overexpressing Nrsn1, one of the newly identified genes undergoing rapid translational repression, or activating ESR1 in the hippocampus impaired memory formation. Collectively, this study unveils the yet-unappreciated importance of gene repression mechanisms for memory formation.
      Authors : Jun Cho, Nam-Kyung Yu, Jun-Hyeok Choi, Su-Eon Sim, SukJae Joshua Kang, Chuljung Kwak, Seung-Woo Lee, Ji-il Kim, Dong Il Choi, V. Narry Kim, Bong-Kiun Kaang
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac7368
  • [Report] Holographic measurements of inhomogeneous cloud mixing at the
           centimeter scale
    • Authors: Matthew J. Beals
      Abstract: Optical properties and precipitation efficiency of atmospheric clouds are largely determined by turbulent mixing with their environment. When cloud liquid water is reduced upon mixing, droplets may evaporate uniformly across the population or, in the other extreme, a subset of droplets may evaporate completely, leaving the remaining drops unaffected. Here, we use airborne holographic imaging to visualize the spatial structure and droplet size distribution at the smallest turbulent scales, thereby observing their response to entrainment and mixing with clear air. The measurements reveal that turbulent clouds are inhomogeneous, with sharp transitions between cloud and clear air properties persisting to dissipative scales (
      PubDate: 2015-10-02
      DOI: 10.1126/science.aab0751
  • [Report] State shift in Deccan volcanism at the Cretaceous-Paleogene
           boundary, possibly induced by impact
    • Authors: Paul R. Renne
      Abstract: Bolide impact and flood volcanism compete as leading candidates for the cause of terminal-Cretaceous mass extinctions. High-precision 40Ar/39Ar data indicate that these two mechanisms may be genetically related, and neither can be considered in isolation. The existing Deccan Traps magmatic system underwent a state shift approximately coincident with the Chicxulub impact and the terminal-Cretaceous mass extinctions, after which ~70% of the Traps' total volume was extruded in more massive and more episodic eruptions. Initiation of this new regime occurred within ~50,000 years of the impact, which is consistent with transient effects of impact-induced seismic energy. Postextinction recovery of marine ecosystems was probably suppressed until after the accelerated volcanism waned.
      Authors : Paul R. Renne, Courtney J. Sprain, Mark A. Richards, Stephen Self, Loÿc Vanderkluysen, Kanchan Pande
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac7549
  • [Report] Ultrafast 2D IR spectroscopy of the excess proton in liquid water
    • Abstract: Despite decades of study, the structures adopted to accommodate an excess proton in water and the mechanism by which they interconvert remain elusive. We used ultrafast two-dimensional infrared (2D IR) spectroscopy to investigate protons in aqueous hydrochloric acid solutions. By exciting O–H stretching vibrations and detecting the spectral response throughout the mid-IR region, we observed the interaction between the stretching and bending vibrations characteristic of the flanking waters of the Zundel complex, [H(H2O)2]+, at 3200 and 1760 cm−1, respectively. From time-dependent shifts of the stretch-bend cross peak, we determined a lower limit on the lifetime of this complex of 480 femtoseconds. These results suggest a key role for the Zundel complex in aqueous proton transfer.
      Authors : Martin Thämer, Luigi De Marco, Krupa Ramasesha, Aritra Mandal, Andrei Tokmakoff
      PubDate: 2015-10-02
      DOI: 10.1126/science.aab3908
  • [Report] End-bonded contacts for carbon nanotube transistors with low,
           size-independent resistance
    • Authors: Qing Cao
      Abstract: Moving beyond the limits of silicon transistors requires both a high-performance channel and high-quality electrical contacts. Carbon nanotubes provide high-performance channels below 10 nanometers, but as with silicon, the increase in contact resistance with decreasing size becomes a major performance roadblock. We report a single-walled carbon nanotube (SWNT) transistor technology with an end-bonded contact scheme that leads to size-independent contact resistance to overcome the scaling limits of conventional side-bonded or planar contact schemes. A high-performance SWNT transistor was fabricated with a sub–10-nanometer contact length, showing a device resistance below 36 kilohms and on-current above 15 microampere per tube. The p-type end-bonded contact, formed through the reaction of molybdenum with the SWNT to form carbide, also exhibited no Schottky barrier. This strategy promises high-performance SWNT transistors, enabling future ultimately scaled device technologies.
      Authors : Qing Cao, Shu-Jen Han, Jerry Tersoff, Aaron D. Franklin, Yu Zhu, Zhen Zhang, George S. Tulevski, Jianshi Tang, Wilfried Haensch
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac8006
  • [Report] Megasupramolecules for safer, cleaner fuel by end association of
           long telechelic polymers
    • Authors: Ming-Hsin Wei
      Abstract: We used statistical mechanics to design polymers that defy conventional wisdom by self-assembling into “megasupramolecules” (≥5000 kg/mol) at low concentration (≤0.3 weight percent). Theoretical treatment of the distribution of individual subunits—end-functional polymers—among cyclic and linear supramolecules (ring-chain equilibrium) predicts that megasupramolecules can form at low total polymer concentration if, and only if, the backbones are long (>400 kg/mol) and end-association strength is optimal. Viscometry and scattering measurements of long telechelic polymers having polycyclooctadiene backbones and acid or amine end groups verify the formation of megasupramolecules. They control misting and reduce drag in the same manner as ultralong covalent polymers. With individual building blocks short enough to avoid hydrodynamic chain scission (weight-average molecular weights of 400 to 1000 kg/mol) and reversible linkages that protect covalent bonds, these megasupramolecules overcome the obstacles of shear degradation and engine incompatibility.
      Authors : Ming-Hsin Wei, Boyu Li, R. L. Ameri David, Simon C. Jones, Virendra Sarohia, Joel A. Schmitigal, Julia A. Kornfield
      PubDate: 2015-10-02
      DOI: 10.1126/science.aab0642
  • [Report] Discovery and spectroscopy of the young jovian planet 51 Eri b
           with the Gemini Planet Imager
    • Authors: B. Macintosh
      Abstract: Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10−6 and an effective temperature of 600 to 750 kelvin. For this age and luminosity, “hot-start” formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the “cold-start” core-accretion process that may have formed Jupiter.
      Authors : B. Macintosh, J. R. Graham, T. Barman, R. J. De Rosa, Q. Konopacky, M. S. Marley, C. Marois, E. L. Nielsen, L. Pueyo, A. Rajan, J. Rameau, D. Saumon, J. J. Wang, J. Patience, M. Ammons, P. Arriaga, E. Artigau, S. Beckwith, J. Brewster, S. Bruzzone, J. Bulger, B. Burningham, A. S. Burrows, C. Chen, E. Chiang, J. K. Chilcote, R. I. Dawson, R. Dong, R. Doyon, Z. H. Draper, G. Duchêne, T. M. Esposito, D. Fabrycky, M. P. Fitzgerald, K. B. Follette, J. J. Fortney, B. Gerard, S. Goodsell, A. Z. Greenbaum, P. Hibon, S. Hinkley, T. H. Cotten, L.-W. Hung, P. Ingraham, M. Johnson-Groh, P. Kalas, D. Lafreniere, J. E. Larkin, J. Lee, M. Line, D. Long, J. Maire, F. Marchis, B. C. Matthews, C. E. Max, S. Metchev, M. A. Millar-Blanchaer, T. Mittal, C. V. Morley, K. M. Morzinski, R. Murray-Clay, R. Oppenheimer, D. W. Palmer, R. Patel, M. D. Perrin, L. A. Poyneer, R. R. Rafikov, F. T. Rantakyrö, E. L. Rice, P. Rojo, A. R. Rudy, J.-B. Ruffio, M. T. Ruiz, N. Sadakuni, L. Saddlemyer, M. Salama, D. Savransky, A. C. Schneider, A. Sivaramakrishnan, I. Song, R. Soummer, S. Thomas, G. Vasisht, J. K. Wallace, K. Ward-Duong, S. J. Wiktorowicz, S. G. Wolff, B. Zuckerman
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac5891
  • [In Depth] New proteins may expand, improve genome editing
    • Authors: Elizabeth Pennisi
      Abstract: Three years ago, no one knew or cared about much about a protein called Cpf1 produced by a bacterial gene. Now, it shows potential for making a fast-developing genome editing technique called CRISPR easier and more accurate. Bioinformaticians identified this protein and its potential connection to CRISPR by scanning the public database of genome sequences. Their colleagues now show that two of 16 versions of this protein tested can delete a gene in a human cell. Cpf1 has other advantages as well—being smaller than one of the popular Cas9 proteins used and depending on a smaller piece of RNA to find its target DNA. But its utility for editing genomes of human and other cells needs further testing. Author: Elizabeth Pennisi
      Keywords: Biology
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.16
  • [Errata] Erratum for the Report “A neoplastic gene fusion mimics
           trans-splicing of RNAs in normal human cells” by H. Li, J. Wang, G.
           Mor, J. Sklar
    • PubDate: 2015-10-02
      DOI: 10.1126/science.aad3463
  • [Editorial] The promise of neurotechnology
    • Authors: Andrew Schwartz
      Abstract: The various brain initiatives for producing new tools, with the goal of advancing neurological therapies, have led to widespread attention on neurotechnology. Perhaps the most exciting aspect of this rapidly expanding field is the prospect of propelling experiments beyond scientific dogma to discover how the brain generates behavior. A sharper focus on this challenge will help direct the development of tools that can elucidate fundamental operations of the brain. Author: Andrew Schwartz
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad5010
  • [In Brief] This week's section
    • Abstract: In science news around the world, scientists from an agricultural research center formerly based in Syria prepare to make the first withdrawal of seeds from the Svalbard Global Seed Vault, China unveils a Cold War–era top-secret satellite and nuclear weapons R&D facility outside Beijing, the U.S. FDA calls out a genetic testing company for failing to seek its approval before marketing a blood test to screen for cancer, U.S. physicists resume their hunt for spacetime ripples known as gravitational waves, Shell abandons its plans to drill for oil in the Chukchi Sea off Alaska "for the foreseeable future," and more. Also, a new study suggests that current pledges by more than 70 nations to reduce greenhouse gas emissions will still overshoot an agreed-upon warming threshold for the planet of 2°C. And a cache of bones found in the Alaskan Arctic reveals a new species of hadrosaur that thrived in the region about 70 million years ago.
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.12
  • [Errata] Erratum for the Report “Spreading depression triggers
           headache by activating neuronal Panx1 channels” by H. Karatas, S. E.
           Erdener, Y. Gursoy-Ozdemir, S. Lule, E. Eren-Koçak, Z. D. Sen, T.
    • PubDate: 2015-10-02
      DOI: 10.1126/science.aad5166
  • [Feature] Pooling resources
    • Authors: Jill U. Adams
      Abstract: As a kid growing up in rural Rhode Island, Aram Calhoun ran the frog patrol. When she caught neighborhood boys throwing frogs into traffic, she'd chase the offenders and beat them up. Then she'd persuade her adversaries to become allies. "I recruited two of the worst ones to my team," the ecologist recalls. "We'd go find frogs and save them." These days, Calhoun takes a similar though less pugilistic approach to her work. But the University of Maine, Orono (UMO), academic is tackling a more difficult task than persuading kids to stop squashing frogs. She's leading an innovative effort here to overcome two of the tougher challenges in conservation biology in the United States: protecting small, ephemeral waterbodies called vernal pools that are critical to the survival of many amphibians and other organisms, and making conservation work on privately held lands. And now her work in two Maine communities is on the verge of setting a precedent for how local communities can work with developers and private landowners to protect sensitive ecosystems—instead of fighting. "I'll admit I was a little skeptical" about Calhoun's effort, says Ruth Ladd of U.S. Army Corps of Engineers in Concord, Massachusetts, a federal agency that plays a major role in protecting wetlands and has been monitoring Calhoun's work. But she has been "tenacious. … As complicated as things were, she always behaved as if it could be done." Author: Jill U. Adams
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.26
  • [Feature] How two pioneers took the tropics' pulse
    • Authors: Eric Hand
      Abstract: Had it been a few years later, Madden-Julian oscillation (MJO), a system of storm clouds moving eastward around the Earth, would have been discovered easily by satellites peering down. But as it was, the discovery of the MJO in 1971 required one of the most powerful punch card computers of its era and the keen insight of two young scientists, Roland Madden and Paul Julian. Using a recently developed technique called the fast Fourier transform, they pried apart one of the longest-running data sets in the Pacific—weather data from Kanton Island, near the equator—to discover the pulsing rhythm of Earth's biggest single driver of tropical weather. Author: Eric Hand
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.25
  • [Essay] Slow or fast? A tale of synaptic vesicle recycling
    • Authors: Shigeki Watanabe
      Abstract: A new model accounts for synaptic transmission speed Author: Shigeki Watanabe
      Keywords: Neuroscience
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad2996
  • [Essay] Brain crystals
    • Authors: Julija Krupic
      Abstract: Our brains may perceive distance differently in environments with polarized geometry Author: Julija Krupic
      Keywords: Neuroscience
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad3002
  • [Essay] Dopamine and serotonin signals for reward across time scales
    • Authors: Jeremiah Y. Cohen
      Abstract: Neurons that release different neurotransmitters transmit different information about rewards Author: Jeremiah Y. Cohen
      Keywords: Neuroscience
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad3003
  • [Book Review] Beyond “publish or perish”
    • Authors: Johanna Gutlerner
      Abstract: Experts have been debating whether we are training too many Ph.D.s for the jobs that exist for more than 40 years, but is this really the problem? While acknowledging that some reduction in the number of trainees may be necessary, Leonard Cassuto has a different solution to the glut of graduate trainees. He believes that focusing on how and what we teach, as well as training our students to teach will help improve the career prospects for the next generation of Ph.D.s. In The Graduate School Mess, Cassuto traces the challenges facing graduate institutions, including antiquated admissions policies; incoherent course offerings; esoteric, gatekeeping qualifying exams; long times to degrees; and failure to prepare students for diverse career outcomes. Though these have been described elsewhere, reviewer Johanna Gutlerner praises the novelty of his proposed solutions. Author: Johanna Gutlerner
      Keywords: Education
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac7868
  • [Book Review] Can you keep a secret?
    • Authors: Giovanni Frazzetto
      Abstract: Secret, a new exhibition at the Science Gallery Dublin, invites visitors to reflect on timely issues of privacy, espionage, and surveillance with a series of enticing works that unite art, design, and media technology. Praising it as "coherent and polished," reviewer Giovanni Frazzetto highlights a number of the show's provocative exhibits: from a robotic hand that delivers a secret message to those who grip it via subtle vibrations in each finger, to a device that allows visitors to visualize their Internet presence. Author: Giovanni Frazzetto
      Keywords: Exhibition
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac6549
  • [Books et al.] Books Received
    • Abstract: A listing of books received at Science during the week ending 25 September 2015.
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.50-b
  • [This Week in Science] Cloud mixing and droplet evolution
    • Authors: H. Jesse Smith
      Abstract: Author: H. Jesse Smith
      Keywords: Clouds
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-a
  • [This Week in Science] Making an impact in more ways than one
    • Authors: Brent Grocholski
      Abstract: Author: Brent Grocholski
      Keywords: Earth History
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-b
  • [This Week in Science] Resilience of the oceans revealed
    • Authors: Shahid Naeem
      Abstract: Author: Shahid Naeem
      Keywords: Ocean Acidification
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-c
  • [This Week in Science] No precedent
    • Authors: Sacha Vignieri
      Abstract: Author: Sacha Vignieri
      Keywords: Paleoecology
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-d
  • [This Week in Science] Motivation helps reverse neuronal damage
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Injury Recovery
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-e
  • [This Week in Science] Building a gate to the nucleus
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: Structural Biology
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-f
  • [This Week in Science] An exoplanet extracted from the bright
    • Authors: Brent Grocholski
      Abstract: Author: Brent Grocholski
      Keywords: Planetary Science
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.52-g
  • [Perspective] It takes the world to understand the brain
    • Authors: Z. Josh Huang
      Abstract: We are on the verge of a fundamental leap toward understanding the human brain, and the implications for health and society are profound. Large-scale brain projects have been launched or are being planned in multiple continents and countries (1–4). In June, about 50 leading scientists from the United States, Europe, Japan, Korea, and China gathered in Suzhou, China (organized by Cold Spring Harbor Asia) to discuss the opportunities and challenges in brain research (5). The benefits of international coordination and collaboration were recognized, and the discussions laid a foundation for future meetings aimed at fleshing out details related to specific goals.
      Authors : Z. Josh Huang, Liqun Luo
      Keywords: Neuroscience
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad4120
  • [Perspective] Clouds resolved
    • Authors: Eberhard Bodenschatz
      Abstract: The pillowing structure and filamentary detail of clouds has inspired many paintings as well as associations to down pillows. Turbulence is at the source of this beauty. It affects aerosol-cloud droplet interaction, cloud particle collisions and merging, and entrainment and mixing of environmental air with clouds (1, 2). These microphysical processes are important for predicting weather and climate (3). Yet it has remained very difficult to observe clouds at the temporal and spatial scales required to gain understanding of these processes. On page 87 of this issue, Beals et al. (4) show that the filamentary structure of entrainment and mixing reaches to the centimeter scale in a cloud. Author: Eberhard Bodenschatz
      Keywords: Atmospheric Science
      PubDate: 2015-10-02
      DOI: 10.1126/science.aad1386
  • [New Products] New Products
    • Abstract: A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.114-a
  • [Podcast] Science Podcast: 2 October Show
    • Abstract: On this week's show: Designing safer jet fuels and a roundup of daily news stories.
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.114-b
  • [Business Office Feature] Advances in Computational Psychophysiology
    • Abstract: Computational psychophysiology is an interdisciplinary field that employs methods from the disciplines of psychology, physiology, neuroscience, computer science, mathematics, and physics to investigate human behavior. Modern technologies, such as positron emission tomography and functional magnetic resonance imaging, now enable researchers to look inside the brain with unprecedented clarity and are facilitating a better understanding of neurological disorders and neurodegenerative diseases. By combining the power of computational techniques with psychophysiology studies, researchers can generate far more in-depth data analyses and a greater understanding of the processes underlying behavior.Read the booklet (PDF, 6.52MB)Read the e-bookletThis special supplement brought to you by the Science/AAAS Custom Publishing Office.
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.114-c
  • [Working Life] After the bombs
    • Authors: Elisabeth Pain
      Abstract: Author: Elisabeth Pain
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.130
  • [Report] Aldehyde dehydrogenase 1a1 mediates a GABA synthesis pathway in
           midbrain dopaminergic neurons
    • Authors: Jae-Ick Kim
      Abstract: Midbrain dopamine neurons are an essential component of the basal ganglia circuitry, playing key roles in the control of fine movement and reward. Recently, it has been demonstrated that γ-aminobutyric acid (GABA), the chief inhibitory neurotransmitter, is co-released by dopamine neurons. Here, we show that GABA co-release in dopamine neurons does not use the conventional GABA-synthesizing enzymes, glutamate decarboxylases GAD65 and GAD67. Our experiments reveal an evolutionarily conserved GABA synthesis pathway mediated by aldehyde dehydrogenase 1a1 (ALDH1a1). Moreover, GABA co-release is modulated by ethanol (EtOH) at concentrations seen in blood alcohol after binge drinking, and diminished ALDH1a1 leads to enhanced alcohol consumption and preference. These findings provide insights into the functional role of GABA co-release in midbrain dopamine neurons, which may be essential for reward-based behavior and addiction.
      Authors : Jae-Ick Kim, Subhashree Ganesan, Sarah X. Luo, Yu-Wei Wu, Esther Park, Eric J. Huang, Lu Chen, Jun B. Ding
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac4690
  • [Report] Crystal structure of the metazoan Nup62•Nup58•Nup54
           nucleoporin complex
    • Authors: Hema Chug
      Abstract: Nuclear pore complexes (NPCs) conduct nucleocytoplasmic transport and gain transport selectivity through nucleoporin FG domains. Here, we report a structural analysis of the FG Nup62•58•54 complex, which is a crucial component of the transport system. It comprises a ≈13 nanometer-long trimerization interface with an unusual 2W3F coil, a canonical heterotrimeric coiled coil, and a kink that enforces a compact six-helix bundle. Nup54 also contains a ferredoxin-like domain. We further identified a heterotrimeric Nup93-binding module for NPC anchorage. The quaternary structure alternations in the Nup62 complex, which were previously proposed to trigger a general gating of the NPC, are incompatible with the trimer structure. We suggest that the highly elongated Nup62 complex projects barrier-forming FG repeats far into the central NPC channel, supporting a barrier that guards the entire cross section.
      Authors : Hema Chug, Sergei Trakhanov, Bastian B. Hülsmann, Tino Pleiner, Dirk Görlich
      PubDate: 2015-10-02
      DOI: 10.1126/science.aac7420
  • [Business Office Feature] Neurophysiology charges ahead
    • Authors: Alan Dove
      Abstract: Author: Alan Dove
      Keywords: Business Office Feature
      PubDate: 2015-10-02
      DOI: 10.1126/science.350.6256.111
  • [Report] Function of the nucleus accumbens in motor control during
           recovery after spinal cord injury
    • Authors: Masahiro Sawada
      Abstract: Motivation facilitates recovery after neuronal damage, but its mechanism is elusive. It is generally thought that the nucleus accumbens (NAc) regulates motivation-driven effort but is not involved in the direct control of movement. Using causality analysis, we identified the flow of activity from the NAc to the sensorimotor cortex (SMC) during the recovery of dexterous finger movements after spinal cord injury at the cervical level in macaque monkeys. Furthermore, reversible pharmacological inactivation of the NAc during the early recovery period diminished high-frequency oscillatory activity in the SMC, which was accompanied by a transient deficit of amelioration in finger dexterity obtained by rehabilitation. These results demonstrate that during recovery after spinal damage, the NAc up-regulates the high-frequency activity of the SMC and is directly involved in the control of finger movements.
      Authors : Masahiro Sawada, Kenji Kato, Takeharu Kunieda, Nobuhiro Mikuni, Susumu Miyamoto, Hirotaka Onoe, Tadashi Isa, Yukio Nishimura
      PubDate: 2015-10-02
      DOI: 10.1126/science.aab3825
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