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Journal Cover   Science
  [SJR: 12.465]   [H-I: 801]   [2134 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]
  • [New Products] New Products
    • Abstract: A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1493-a
       
  • [Podcast] Science Podcast: 26 June Show
    • Abstract: On this week's show: Making metallic hydrogen and a roundup of daily news stories.
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1493-b
       
  • [Working Life] The health of those who study health
    • Authors: Rachel Bernstein
      Abstract: Author: Rachel Bernstein
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1506
       
  • [Report] Factor-dependent processivity in human eIF4A DEAD-box helicase
    • Authors: Cuauhtémoc García-García
      Abstract: During eukaryotic translation initiation, the small ribosomal subunit, assisted by initiation factors, locates the messenger RNA start codon by scanning from the 5′ cap. This process is powered by the eukaryotic initiation factor 4A (eIF4A), a DEAD-box helicase. eIF4A has been thought to unwind structures formed in the untranslated 5′ region via a nonprocessive mechanism. Using a single-molecule assay, we found that eIF4A functions instead as an adenosine triphosphate–dependent processive helicase when complexed with two accessory proteins, eIF4G and eIF4B. Translocation occurred in discrete steps of 11 ± 2 base pairs, irrespective of the accessory factor combination. Our findings support a memory-less stepwise mechanism for translation initiation and suggest that similar factor-dependent processivity may be shared by other members of the DEAD-box helicase family.
      Authors : Cuauhtémoc García-García, Kirsten L. Frieda, Kateryna Feoktistova, Christopher S. Fraser, Steven M. Block
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa5089
       
  • [Report] Discrete functions of nuclear receptor Rev-erbα couple
           metabolism to the clock
    • Authors: Yuxiang Zhang
      Abstract: Circadian and metabolic physiology are intricately intertwined, as illustrated by Rev-erbα, a transcription factor (TF) that functions both as a core repressive component of the cell-autonomous clock and as a regulator of metabolic genes. Here, we show that Rev-erbα modulates the clock and metabolism by different genomic mechanisms. Clock control requires Rev-erbα to bind directly to the genome at its cognate sites, where it competes with activating ROR TFs. By contrast, Rev-erbα regulates metabolic genes primarily by recruiting the HDAC3 co-repressor to sites to which it is tethered by cell type–specific transcription factors. Thus, direct competition between Rev-erbα and ROR TFs provides a universal mechanism for self-sustained control of the molecular clock across all tissues, whereas Rev-erbα uses lineage-determining factors to convey a tissue-specific epigenomic rhythm that regulates metabolism tailored to the specific need of that tissue.
      Authors : Yuxiang Zhang, Bin Fang, Matthew J. Emmett, Manashree Damle, Zheng Sun, Dan Feng, Sean M. Armour, Jarrett R. Remsberg, Jennifer Jager, Raymond E. Soccio, David J. Steger, Mitchell A. Lazar
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab3021
       
  • [Report] A Cas9–guide RNA complex preorganized for target DNA
           recognition
    • Authors: Fuguo Jiang
      Abstract: Bacterial adaptive immunity uses CRISPR (clustered regularly interspaced short palindromic repeats)–associated (Cas) proteins together with CRISPR transcripts for foreign DNA degradation. In type II CRISPR-Cas systems, activation of Cas9 endonuclease for DNA recognition upon guide RNA binding occurs by an unknown mechanism. Crystal structures of Cas9 bound to single-guide RNA reveal a conformation distinct from both the apo and DNA-bound states, in which the 10-nucleotide RNA “seed” sequence required for initial DNA interrogation is preordered in an A-form conformation. This segment of the guide RNA is essential for Cas9 to form a DNA recognition–competent structure that is poised to engage double-stranded DNA target sequences. We construe this as convergent evolution of a “seed” mechanism reminiscent of that used by Argonaute proteins during RNA interference in eukaryotes.
      Authors : Fuguo Jiang, Kaihong Zhou, Linlin Ma, Saskia Gressel, Jennifer A. Doudna
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab1452
       
  • [Report] Epigenetic silencing by the HUSH complex mediates position-effect
           variegation in human cells
    • Authors: Iva A. Tchasovnikarova
      Abstract: Forward genetic screens in Drosophila melanogaster for modifiers of position-effect variegation have revealed the basis of much of our understanding of heterochromatin. We took an analogous approach to identify genes required for epigenetic repression in human cells. A nonlethal forward genetic screen in near-haploid KBM7 cells identified the HUSH (human silencing hub) complex, comprising three poorly characterized proteins, TASOR, MPP8, and periphilin; this complex is absent from Drosophila but is conserved from fish to humans. Loss of HUSH components resulted in decreased H3K9me3 both at endogenous genomic loci and at retroviruses integrated into heterochromatin. Our results suggest that the HUSH complex is recruited to genomic loci rich in H3K9me3, where subsequent recruitment of the methyltransferase SETDB1 is required for further H3K9me3 deposition to maintain transcriptional silencing.
      Authors : Iva A. Tchasovnikarova, Richard T. Timms, Nicholas J. Matheson, Kim Wals, Robin Antrobus, Berthold Göttgens, Gordon Dougan, Mark A. Dawson, Paul J. Lehner
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa7227
       
  • [Report] Identification of the algal dimethyl sulfide–releasing
           enzyme: A missing link in the marine sulfur cycle
    • Authors: Uria Alcolombri
      Abstract: Algal blooms produce large amounts of dimethyl sulfide (DMS), a volatile with a diverse signaling role in marine food webs that is emitted to the atmosphere, where it can affect cloud formation. The algal enzymes responsible for forming DMS from dimethylsulfoniopropionate (DMSP) remain unidentified despite their critical role in the global sulfur cycle. We identified and characterized Alma1, a DMSP lyase from the bloom-forming algae Emiliania huxleyi. Alma1 is a tetrameric, redox-sensitive enzyme of the aspartate racemase superfamily. Recombinant Alma1 exhibits biochemical features identical to the DMSP lyase in E. huxleyi, and DMS released by various E. huxleyi isolates correlates with their Alma1 levels. Sequence homology searches suggest that Alma1 represents a gene family present in major, globally distributed phytoplankton taxa and in other marine organisms.
      Authors : Uria Alcolombri, Shifra Ben-Dor, Ester Feldmesser, Yishai Levin, Dan S. Tawfik, Assaf Vardi
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab1586
       
  • [Report] Possible artifacts of data biases in the recent global surface
           warming hiatus
    • Authors: Thomas R. Karl
      Abstract: Much study has been devoted to the possible causes of an apparent decrease in the upward trend of global surface temperatures since 1998, a phenomenon that has been dubbed the global warming “hiatus.” Here, we present an updated global surface temperature analysis that reveals that global trends are higher than those reported by the Intergovernmental Panel on Climate Change, especially in recent decades, and that the central estimate for the rate of warming during the first 15 years of the 21st century is at least as great as the last half of the 20th century. These results do not support the notion of a “slowdown” in the increase of global surface temperature.
      Authors : Thomas R. Karl, Anthony Arguez, Boyin Huang, Jay H. Lawrimore, James R. McMahon, Matthew J. Menne, Thomas C. Peterson, Russell S. Vose, Huai-Min Zhang
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa5632
       
  • [Report] A parvalbumin-positive excitatory visual pathway to trigger fear
           responses in mice
    • Authors: Congping Shang
      Abstract: The fear responses to environmental threats play a fundamental role in survival. Little is known about the neural circuits specifically processing threat-relevant sensory information in the mammalian brain. We identified parvalbumin-positive (PV+) excitatory projection neurons in mouse superior colliculus (SC) as a key neuronal subtype for detecting looming objects and triggering fear responses. These neurons, distributed predominantly in the superficial SC, divergently projected to different brain areas, including the parabigeminal nucleus (PBGN), an intermediate station leading to the amygdala. Activation of the PV+ SC-PBGN pathway triggered fear responses, induced conditioned aversion, and caused depression-related behaviors. Approximately 20% of mice subjected to the fear-conditioning paradigm developed a generalized fear memory.
      Authors : Congping Shang, Zhihui Liu, Zijun Chen, Yingchao Shi, Qian Wang, Su Liu, Dapeng Li, Peng Cao
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa8694
       
  • [Report] Genomic determinants of coral heat tolerance across latitudes
    • Authors: Groves B. Dixon
      Abstract: As global warming continues, reef-building corals could avoid local population declines through “genetic rescue” involving exchange of heat-tolerant genotypes across latitudes, but only if latitudinal variation in thermal tolerance is heritable. Here, we show an up–to–10-fold increase in odds of survival of coral larvae under heat stress when their parents come from a warmer lower-latitude location. Elevated thermal tolerance was associated with heritable differences in expression of oxidative, extracellular, transport, and mitochondrial functions that indicated a lack of prior stress. Moreover, two genomic regions strongly responded to selection for thermal tolerance in interlatitudinal crosses. These results demonstrate that variation in coral thermal tolerance across latitudes has a strong genetic basis and could serve as raw material for natural selection.
      Authors : Groves B. Dixon, Sarah W. Davies, Galina A. Aglyamova, Eli Meyer, Line K. Bay, Mikhail V. Matz
      PubDate: 2015-06-26
      DOI: 10.1126/science.1261224
       
  • [Report] A 12 Å carotenoid translocation in a photoswitch associated
           with cyanobacterial photoprotection
    • Authors: Ryan L. Leverenz
      Abstract: Pigment-protein and pigment-pigment interactions are of fundamental importance to the light-harvesting and photoprotective functions essential to oxygenic photosynthesis. The orange carotenoid protein (OCP) functions as both a sensor of light and effector of photoprotective energy dissipation in cyanobacteria. We report the atomic-resolution structure of an active form of the OCP consisting of the N-terminal domain and a single noncovalently bound carotenoid pigment. The crystal structure, combined with additional solution-state structural data, reveals that OCP photoactivation is accompanied by a 12 angstrom translocation of the pigment within the protein and a reconfiguration of carotenoid-protein interactions. Our results identify the origin of the photochromic changes in the OCP triggered by light and reveal the structural determinants required for interaction with the light-harvesting antenna during photoprotection.
      Authors : Ryan L. Leverenz, Markus Sutter, Adjélé Wilson, Sayan Gupta, Adrien Thurotte, Céline Bourcier de Carbon, Christopher J. Petzold, Corie Ralston, François Perreau, Diana Kirilovsky, Cheryl A. Kerfeld
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa7234
       
  • [Report] Atomic gold–enabled three-dimensional lithography for
           silicon mesostructures
    • Authors: Zhiqiang Luo
      Abstract: Three-dimensional (3D) mesostructured semiconductors show promising properties and applications; however, to date, few methods exist to synthesize or fabricate such materials. Metal can diffuse along semiconductor surfaces, and even trace amounts can change the surface behavior. We exploited the phenomena for 3D mesoscale lithography, by showing one example where iterated deposition-diffusion-incorporation of gold over silicon nanowires forms etchant-resistant patterns. This process is facet-selective, producing mesostructured silicon spicules with skeletonlike morphology, 3D tectonic motifs, and reduced symmetries. Atom-probe tomography, coupled with other quantitative measurements, indicates the existence and the role of individual gold atoms in forming 3D lithographic resists. Compared to other more uniform silicon structures, the anisotropic spicule requires greater force for detachment from collagen hydrogels, suggesting enhanced interfacial interactions at the mesoscale.
      Authors : Zhiqiang Luo, Yuanwen Jiang, Benjamin D. Myers, Dieter Isheim, Jinsong Wu, John F. Zimmerman, Zongan Wang, Qianqian Li, Yucai Wang, Xinqi Chen, Vinayak P. Dravid, David N. Seidman, Bozhi Tian
      PubDate: 2015-06-26
      DOI: 10.1126/science.1257278
       
  • [Report] Direct observation of an abrupt insulator-to-metal transition in
           dense liquid deuterium
    • Authors: M. D. Knudson
      Abstract: Eighty years ago, it was proposed that solid hydrogen would become metallic at sufficiently high density. Despite numerous investigations, this transition has not yet been experimentally observed. More recently, there has been much interest in the analog of this predicted metallic transition in the dense liquid, due to its relevance to planetary science. Here, we show direct observation of an abrupt insulator-to-metal transition in dense liquid deuterium. Experimental determination of the location of this transition provides a much-needed benchmark for theory and may constrain the region of hydrogen-helium immiscibility and the boundary-layer pressure in standard models of the internal structure of gas-giant planets.
      Authors : M. D. Knudson, M. P. Desjarlais, A. Becker, R. W. Lemke, K. R. Cochrane, M. E. Savage, D. E. Bliss, T. R. Mattsson, R. Redmer
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa7471
       
  • [Report] Overcoming Kerr-induced capacity limit in optical fiber
           transmission
    • Authors: E. Temprana
      Abstract: Nonlinear optical response of silica imposes a fundamental limit on the information transfer capacity in optical fibers. Communication beyond this limit requires higher signal power and suppression of nonlinear distortions to prevent irreversible information loss. The nonlinear interaction in silica is a deterministic phenomenon that can, in principle, be completely reversed. However, attempts to remove the effects of nonlinear propagation have led to only modest improvements, and the precise physical mechanism preventing nonlinear cancellation remains unknown. We demonstrate that optical carrier stability plays a critical role in canceling Kerr-induced distortions and that nonlinear wave interaction in silica can be substantially reverted if optical carriers possess a sufficient degree of mutual coherence. These measurements indicate that fiber information capacity can be notably increased over previous estimates.
      Authors : E. Temprana, E. Myslivets, B.P.-P. Kuo, L. Liu, V. Ataie, N. Alic, S. Radic
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab1781
       
  • [Report] Quantum spin Hall effect of light
    • Authors: Konstantin Y. Bliokh
      Abstract: Maxwell’s equations, formulated 150 years ago, ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to the spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect—surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes. This deepens our understanding of Maxwell’s theory, reveals analogies with topological insulators for electrons, and offers applications for robust spin-directional optical interfaces.
      Authors : Konstantin Y. Bliokh, Daria Smirnova, Franco Nori
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa9519
       
  • [Research Article] Integration of Bmp and Wnt signaling by Hopx specifies
           commitment of cardiomyoblasts
    • Authors: Rajan Jain
      Abstract: Cardiac progenitor cells are multipotent and give rise to cardiac endothelium, smooth muscle, and cardiomyocytes. Here, we define and characterize the cardiomyoblast intermediate that is committed to the cardiomyocyte fate, and we characterize the niche signals that regulate commitment. Cardiomyoblasts express Hopx, which functions to coordinate local Bmp signals to inhibit the Wnt pathway, thus promoting cardiomyogenesis. Hopx integrates Bmp and Wnt signaling by physically interacting with activated Smads and repressing Wnt genes. The identification of the committed cardiomyoblast that retains proliferative potential will inform cardiac regenerative therapeutics. In addition, Bmp signals characterize adult stem cell niches in other tissues where Hopx-mediated inhibition of Wnt is likely to contribute to stem cell quiescence and to explain the role of Hopx as a tumor suppressor.
      Authors : Rajan Jain, Deqiang Li, Mudit Gupta, Lauren J. Manderfield, Jamie L. Ifkovits, Qiaohong Wang, Feiyan Liu, Ying Liu, Andrey Poleshko, Arun Padmanabhan, Jeffrey C. Raum, Li Li, Edward E. Morrisey, Min Min Lu, Kyoung-Jae Won, Jonathan A. Epstein
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa6071
       
  • [This Week in Science] Finding better immunosuppressants
    • Authors: John F. Foley
      Abstract: Author: John F. Foley
      Keywords: Drug Discovery
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-t
       
  • [Editors' Choice] Cultural imprints on the human genome
    • Authors: Laura M. Zahn
      Abstract: Author: Laura M. Zahn
      Keywords: Human Genetics
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1441-a
       
  • [Editors' Choice] A sex-determining interaction
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: DNA Binding
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1441-b
       
  • [Editors' Choice] A new way to reduce drug seeking
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Neuroscience
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1441-c
       
  • [Editors' Choice] How bladder cells kick out unwelcome intruders
    • Authors: Stella M. Hurtley
      Abstract: Author: Stella M. Hurtley
      Keywords: Microbiology
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1441-d
       
  • [Editors' Choice] Seeing single fermions in optical lattices
    • Authors: Jelena Stajic
      Abstract: Author: Jelena Stajic
      Keywords: Physics
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1441-e
       
  • [Editors' Choice] A faster way to weigh electrode products
    • Authors: Jake Yeston
      Abstract: Author: Jake Yeston
      Keywords: Analytical Chemistry
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1441-f
       
  • [Editors' Choice] A PORTAAL to active learning
    • Authors: Melissa McCartney
      Abstract: Author: Melissa McCartney
      Keywords: Education
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1441-g
       
  • [Review] BMP gradients: A paradigm for morphogen-mediated developmental
           patterning
    • Authors: Ethan Bier
      Abstract: Bone morphogenetic proteins (BMPs) act in dose-dependent fashion to regulate cell fate choices in a myriad of developmental contexts. In early vertebrate and invertebrate embryos, BMPs and their antagonists establish epidermal versus central nervous system domains. In this highly conserved system, BMP antagonists mediate the neural-inductive activities proposed by Hans Spemann and Hilde Mangold nearly a century ago. BMPs distributed in gradients subsequently function as morphogens to subdivide the three germ layers into distinct territories and act to organize body axes, regulate growth, maintain stem cell niches, or signal inductively across germ layers. In this Review, we summarize the variety of mechanisms that contribute to generating reliable developmental responses to BMP gradients and other morphogen systems.
      Authors : Ethan Bier, Edward M. De Robertis
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa5838
       
  • [This Week in Science] BMP mophogens direct growth and fate
    • Authors: Beverly A. Purnell
      Abstract: Author: Beverly A. Purnell
      Keywords: Embryo Development
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-k
       
  • [This Week in Science] Making cardiomyocytes
    • Authors: Beverly A. Purnell
      Abstract: Author: Beverly A. Purnell
      Keywords: Heart Development
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-l
       
  • [This Week in Science] A quantum twist on classical optics
    • Authors: Ian S. Osborne
      Abstract: Author: Ian S. Osborne
      Keywords: Optics
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-m
       
  • [This Week in Science] Driving liquid deuterium into metal
    • Authors: Brent Grocholski
      Abstract: Author: Brent Grocholski
      Keywords: High-Pressure Physics
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-n
       
  • [This Week in Science] Sourcing the smell of the seaside
    • Authors: Nicholas S. Wigginton
      Abstract: Author: Nicholas S. Wigginton
      Keywords: Marine Sulfur Cycle
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-o
       
  • [This Week in Science] Keeping quiet one gene at a time
    • Authors: Stella M. Hurtley
      Abstract: Author: Stella M. Hurtley
      Keywords: Gene Silencing
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-p
       
  • [This Week in Science] Unwinding RNA for protein synthesis
    • Authors: Guy Riddihough
      Abstract: Author: Guy Riddihough
      Keywords: RNA Biochemistry
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-q
       
  • [This Week in Science] More than the sum of its parts
    • Authors: Julia Fahrenkamp-Uppenbrink
      Abstract: Author: Julia Fahrenkamp-Uppenbrink
      Keywords: Synthetic Ecology
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-r
       
  • [This Week in Science] Benefits of breastfeeding
    • Authors: Lisa Chong
      Abstract: Author: Lisa Chong
      Keywords: Microbiota
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-s
       
  • [This Week in Science] Complex shapes from chemical lithography
    • Authors: Marc S. Lavine
      Abstract: Author: Marc S. Lavine
      Keywords: 3D Lithography
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-b
       
  • [This Week in Science] A green way to clean up an oil spill
    • Authors: Zakya H. Kafafi
      Abstract: Author: Zakya H. Kafafi
      Keywords: Materials Chemistry
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-c
       
  • [This Week in Science] Multitasking around the clock
    • Authors: Paula A. Kiberstis
      Abstract: Author: Paula A. Kiberstis
      Keywords: Gene Regulation
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-d
       
  • [This Week in Science] Looming in on the threat-response circuit
    • Authors: Peter Stern
      Abstract: Author: Peter Stern
      Keywords: Brain Circuits
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-e
       
  • [This Week in Science] B12 boosts acne via the microbiota
    • Authors: Angela Colmone
      Abstract: Author: Angela Colmone
      Keywords: Dermatology
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-f
       
  • [This Week in Science] An RNA seed poised to meet its target
    • Authors: Guy Riddihough
      Abstract: Author: Guy Riddihough
      Keywords: Structural Biology
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-g
       
  • [This Week in Science] Protection from too much light
    • Authors: Nicholas S. Wigginton
      Abstract: Author: Nicholas S. Wigginton
      Keywords: Photosynthesis
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-h
       
  • [This Week in Science] Walking back talk of the end of warming
    • Authors: H. Jesse Smith
      Abstract: Author: H. Jesse Smith
      Keywords: Climate Change
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-i
       
  • [This Week in Science] Getting around the capacity crunch
    • Authors: Ian S. Osborne
      Abstract: Author: Ian S. Osborne
      Keywords: Applied Optics
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-j
       
  • [Association Affairs] Breaking through the polycarbonate ceiling
    • PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1439
       
  • [This Week in Science] Some like it hot
    • Authors: Sacha Vignieri
      Abstract: Author: Sacha Vignieri
      Keywords: Coral Reefs
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1440-a
       
  • [Technical Comment] Comment on “Number-space mapping in the newborn
           chick resembles humans’ mental number line”
    • Authors: Madhur Mangalam
      Abstract: Rugani et al. (Reports, 30 January 3015, p. 534) tested 3-day-old domestic chicks using an innovative experimental setup and demonstrate the presence of the mental number line. We raise concerns regarding this conclusion by highlighting the possible loopholes in the experimental design and the data analysis procedures. We further suggest auxiliary experiments that can substantiate the authors’ claim.
      Authors : Madhur Mangalam, Shraddha Madhav Karve
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa8577
       
  • [Technical Comment] Comment on “Number-space mapping in the newborn
           chick resembles humans’ mental number line”
    • Authors: Christopher Harshaw
      Abstract: Rugani et al. (Reports, 30 January 2015, p. 534) presented evidence that domestic chicks employ a “mental number line.” I argue that the hypothesis testing used to support this claim unjustifiably assumes that domestic chicks are unbiased when choosing between identical stimuli presented to their left and right. Author: Christopher Harshaw
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa9565
       
  • [Technical Response] Response to Comments on “Number-space mapping
           in the newborn chick resembles humans’ mental number line”
    • Authors: Rosa Rugani
      Abstract: Mangalam and Karve raise concerns on whether our results demonstrate a mental number line, suggesting auxiliary experiments. Further data analyses show that their methodological concerns are not founded. Harshaw suggests that a side bias could have affected our results. We show that this concern is also unfounded.
      Authors : Rosa Rugani, Giorgio Vallortigara, Konstantinos Priftis, Lucia Regolin
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab0002
       
  • [Books et al.] Books Received
    • Abstract: A listing of books received at Science during the week ending 19 June 2015.
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1436-b
       
  • [Letter] Applying antibiotics lessons to antivirals
    • Authors: David W. Martin
      Abstract: Author: David W. Martin
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1437-a
       
  • [Letter] Response—Applying antibiotics lessons to antivirals
    • Authors: Elena Bekerman
      Abstract:
      Authors : Elena Bekerman, Shirit Einav
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1437-b
       
  • [Letter] China legitimizes ivory, again
    • Authors: Jinqi Zhan
      Abstract:
      Authors : Jinqi Zhan, Qiang Weng
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1437-c
       
  • [Technical Comment] Comment on “Global diversity and geography of
           soil fungi”
    • Authors: Christopher W. Schadt
      Abstract: Tedersoo et al. (Research Article, 28 November 2014, p. 1078) present a compelling study regarding patterns of biodiversity of fungi, carried out at a scale unprecedented to date for fungal biogeographical studies. The study demonstrates strong global biogeographic patterns in richness and community composition of soil fungi. What concerns us with the study is what we do not see. Unfortunately, this study underestimates the fungal diversity of one key group of soil fungi due to reliance on a single primer with known flaws.
      Authors : Christopher W. Schadt, Anna Rosling
      PubDate: 2015-06-26
      DOI: 10.1126/science.aaa4269
       
  • [Perspective] Topology, spin, and light
    • Authors: Michael Stone
      Abstract: Ocean waves form between air and water, and both winds and currents decay exponentially with distance from the water surface. Similar evanescent surface waves may occur whenever two substances with differing physical properties meet—but some are special cases because they must exist for topological reasons. Such mandated surface modes occur in the low-energy quasi-particle spectrum of p-wave superconductors and superfluids and constitute the defining feature of the electronic properties of topological insulators. On page 1448 of this issue, Bliokh et al. (1) suggest that we add evanescent solutions of Maxwell's equations to this list of special cases, and in particular, the coupled oscillations of the electromagnetic field and the near-surface electrons in a metal that are known as surface plasmon-polaritons. Author: Michael Stone
      Keywords: Optics
      PubDate: 2015-06-26
      DOI: 10.1126/science.aac4368
       
  • [Perspective] A HUSH for transgene expression
    • Authors: Thijn R. Brummelkamp
      Abstract: The introduction of an extra gene into a genome—transgenesis—is frequently used as an experimental approach to study gene function but also has applications in biotechnology and gene therapy efforts. In mammalian cells, transgenes are often integrated in a random manner leading to variable levels of expression, with differences as great as three orders of magnitude depending on the integration site (1). The complications of unpredictable levels of transgene expression are well recognized, but the mechanisms leading to variable expression are poorly understood. On page 1481 of this issue, Tchasovnikarova et al. (2) determine that a protein complex silences extra genes that are inserted into heterochromatin, regions of compacted DNA. This represents a new aspect of gene regulation that depends on chromatin context.
      Authors : Thijn R. Brummelkamp, Bas van Steensel
      Keywords: Gene Regulation
      PubDate: 2015-06-26
      DOI: 10.1126/science.aac6529
       
  • [Book Review] The living element
    • Authors: Helen Anne Curry
      Abstract: "If anything in the world is alive, is not radium alive?" asked the physician and journalist C. W. Saleeby in 1906. Writing at the height of a radium craze that swept across Europe and America in the early 20th century, Saleeby was one of many observers who connected radium and radioactivity to the mysteries of life. These couplings—and the curious, marvelous, and mostly forgotten scientific investigations that emanated from them—are the subject of the historian Luis A. Campos's fascinating history of radium and its uses in biological experimentation. Reviewer Helen Anne Curry praises the book's capable use of radium to reveal long-lost secrets of science and history alike. Author: Helen Anne Curry
      Keywords: History of Science
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab3104
       
  • [Book Review] Best practices for digital teaching
    • Authors: Erin Dolan
      Abstract: Anyone teaching a course at a university is likely to have a notion of what face-to-face teaching should look like through his or her experience as a student, as a teacher, and through depictions in media. Yet as Claire Howell Major points out in her book, Teaching Online, most of us do not have similar notions for online courses because we have little to no experience with them. She aims to provide the guidance needed to envision and implement online teaching. Reviewer Erin Dolan finds that much of the book's guidance is also highly relevant for face-to-face teaching, and encourages disciplinary faculty to engage with the book's evidence-based strategies. Author: Erin Dolan
      Keywords: Education
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab3320
       
  • [Perspective] Bearing down on hydrogen
    • Authors: Graeme J. Ackland
      Abstract: Under high pressure, electrons can be squeezed out of the covalent bond that holds the hydrogen molecule together. Under these conditions, condensed hydrogen can become metallic, but the pressures required can be obtained only through the gravitational field of gas giant planets, or fleetingly in shock waves. On page 1455 of this issue, Knudson et al. (1) report experiments using the Z machine at Sandia National Laboratories that uses an aluminum plate propelled by giant capacitors to generate concentrated shock waves in a tiny sample (2). They observe metallic liquid hydrogen at pressures around 300 GPa and temperatures between 1000 and 2000 K created for a tenth of a microsecond. By shock wave standards, that is remarkably cold and slow. Author: Graeme J. Ackland
      Keywords: Materials Science
      PubDate: 2015-06-26
      DOI: 10.1126/science.aac6626
       
  • [Perspective] Who can cleave DMSP?
    • Authors: Andrew W. B. Johnston
      Abstract: Marine organisms play a key role in the global sulfur cycle by producing dimethyl sulfide (DMS), a volatile compound that is emitted into the atmosphere. On page 1466 of this issue, Alcolombri et al. (1) report how the abundant marine phytoplankton Emiliania huxleyi (see the image) produces DMS from dimethylsulfoniopropionate (DMSP). Using a series of classical biochemical approaches, augmented by genomic and proteomic analyses, the authors isolated the enzyme and corresponding gene (termed Alma1) that cleaves DMSP into acrylate and DMS. They also found a functional Alma1-like enzyme in a dinoflagellate, a very different type of abundant single-cell marine plankton, emphasizing the widespread importance of this newly discovered DMSP lyase. Author: Andrew W. B. Johnston
      Keywords: Biogeochemistry
      PubDate: 2015-06-26
      DOI: 10.1126/science.aac5661
       
  • [Perspective] Mother's littlest helpers
    • Authors: Katie Hinde
      Abstract: Commensal bacteria underlie, in part, our nutritional status, immune function, and psychological well-being. The trillions of beneficial microbes within our intestinal tract convert dietary nutrients, inhibit pathogen colonization, regulate immune processes, and produce neural signals (1, 2). Advances in our understanding of the importance of microbes have motivated the commercial development of products intended to boost “good” commensals and confer health benefits. Probiotic dietary supplements contain live beneficial microbes hoped to subsequently colonize the gut. Prebiotic nutrients are thought to enhance good gastrointestinal microflora by preferentially nourishing beneficial microbes. Even “psychobiotics” are being explored to ameliorate symptoms of psychiatric illness. These live organisms influence the brain through metabolites and neuroactive compounds in rodent models and preliminary human studies (3). How to most effectively be the landscape architects of our microbial community, however, often remains unclear. An opportunity to gain insights into how natural selection has shaped the coevolution of hosts and microbes can be found in mammalian mother-infant dyads, as our microbiota are ecologically engineered by mothers and breastmilk. Such insights can be leveraged to improve clinical management and nutritional technologies, enhancing human health not just in infancy, but across the life course (4, 5).
      Authors : Katie Hinde, Zachery T. Lewis
      Keywords: Microbiota
      PubDate: 2015-06-26
      DOI: 10.1126/science.aac7436
       
  • [Policy Forum] Self-correction in science at work
    • Authors: Bruce Alberts
      Abstract: Week after week, news outlets carry word of new scientific discoveries, but the media sometimes give suspect science equal play with substantive discoveries. Careful qualifications about what is known are lost in categorical headlines. Rare instances of misconduct or instances of irreproducibility are translated into concerns that science is broken. The October 2013 Economist headline proclaimed “Trouble at the lab: Scientists like to think of science as self-correcting. To an alarming degree, it is not” (1). Yet, that article is also rich with instances of science both policing itself, which is how the problems came to The Economist's attention in the first place, and addressing discovered lapses and irreproducibility concerns. In light of such issues and efforts, the U.S. National Academy of Sciences (NAS) and the Annenberg Retreat at Sunnylands convened our group to examine ways to remove some of the current disincentives to high standards of integrity in science.
      Authors : Bruce Alberts, Ralph J. Cicerone, Stephen E. Fienberg, Alexander Kamb, Marcia McNutt, Robert M. Nerem, Randy Schekman, Richard Shiffrin, Victoria Stodden, Subra Suresh, Maria T. Zuber, Barbara Kline Pope, Kathleen Hall Jamieson
      Keywords: Scientific Integrity
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab3847
       
  • [Policy Forum] Promoting an open research culture
    • Authors: B. A. Nosek
      Abstract: Transparency, openness, and reproducibility are readily recognized as vital features of science (1, 2). When asked, most scientists embrace these features as disciplinary norms and values (3). Therefore, one might expect that these valued features would be routine in daily practice. Yet, a growing body of evidence suggests that this is not the case (4–6).
      Authors : B. A. Nosek, G. Alter, G. C. Banks, D. Borsboom, S. D. Bowman, S. J. Breckler, S. Buck, C. D. Chambers, G. Chin, G. Christensen, M. Contestabile, A. Dafoe, E. Eich, J. Freese, R. Glennerster, D. Goroff, D. P. Green, B. Hesse, M. Humphreys, J. Ishiyama, D. Karlan, A. Kraut, A. Lupia, P. Mabry, T. A. Madon, N. Malhotra, E. Mayo-Wilson, M. McNutt, E. Miguel, E. Levy Paluck, U. Simonsohn, C. Soderberg, B. A. Spellman, J. Turitto, G. VandenBos, S. Vazire, E. J. Wagenmakers, R. Wilson, T. Yarkoni
      Keywords: Scientific Standards
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab2374
       
  • [Perspective] Ecological communities by design
    • Authors: James K. Fredrickson
      Abstract: In synthetic ecology, a nascent offshoot of synthetic biology, scientists aim to design and construct microbial communities with desirable properties. Such mixed populations of microorganisms can simultaneously perform otherwise incompatible functions (1). Compared with individual organisms, they can also better resist losses in function as a result of environmental perturbation or invasion by other species (2). Synthetic ecology may thus be a promising approach for developing robust, stable biotechnological processes, such as the conversion of cellulosic biomass to biofuels (3). However, achieving this will require detailed knowledge of the principles that guide the structure and function of microbial communities (see the image). Author: James K. Fredrickson
      Keywords: Ecology
      PubDate: 2015-06-26
      DOI: 10.1126/science.aab0946
       
  • [Feature] Mission controller
    • Authors: Eric Hand
      Abstract: On 14 July, NASA's New Horizons spacecraft will swoop past Pluto, the gatekeeper to a region of thousands of icy bodies known as the Kuiper belt. Alan Stern is the principal investigator for the $700 million mission—the largest and most expensive ever controlled by a non-NASA employee. Equal parts taskmaster, entrepreneur, and showman, Stern has been working for 25 years to get a spacecraft to Pluto—10 years to muster political and scientific will, 5 years to build a spacecraft, and nearly 10 years to make the trip. Like the instrument-studded spacecraft—delivered on time and on budget —Stern is packed with purpose. Author: Eric Hand
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1414
       
  • [Feature] Alan Stern's worldly ventures
    • Authors: Eric Hand
      Abstract: Even while getting a NASA spacecraft to Pluto, Alan Stern has found time to set up two companies on the side. One, called Golden Spike, plans to sell billion-dollar trips to the moon to other nations. Another, called Uwingu, promotes gimmicky campaigns—such as selling unofficial naming rights to martian craters—in order to raise money for space research. Author: Eric Hand
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1419
       
  • [In Depth] Breaking the light barrier
    • Authors: Robert F. Service
      Abstract: Soaring traffic on global fiber optic networks could reduce the Internet to gridlock within a couple of years. But new work reported this week in Science could push that "capacity crunch" back several years. Researchers at the University of California, San Diego, targeted fluctuations in the wavelength of the lasers that generate data-carrying light pulses. Those tiny changes create "noise" that builds up with distance, limiting the range of optical signals. Because the noise is random, it's usually impossible to filter out. But the scientists discovered an optical trick that converts it into a form that's easier to separate from the main signal. As a result, they say, light pulses can either carry twice as much data or travel twice as far before needing to be amplified. Author: Robert F. Service
      Keywords: Optics
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1409
       
  • [In Depth] Tapping a nuclear test ban treasure-trove
    • Authors: Daniel Clery
      Abstract: The Comprehensive Nuclear-Test-Ban Treaty (CTBT) has spawned a globe-girdling network of 300 detector stations that sniff out radionuclides, listen for low-frequency sounds, and record tremors—all to discern whether countries are carrying out clandestine nuclear weapons tests. And the treaty has not yet even come into force; the United States remains a prominent holdout. But the CTBT's $1 billion International Monitoring System is 90% complete and has scored notable successes. Among them: sizing up North Korea's nuclear tests, plotting the spread of radionuclides from the Fukushima nuclear accident, and tracking the spectacular Chelyabinsk meteorite as it broke up over Siberia in 2013. This global stethoscope is amassing a treasure trove of data. Initially, the CTBT Organization (CTBTO), based in Vienna, didn't share, but after the 2004 Indian Ocean tsunami—when the monitoring system could have given an early warning—things have loosened up. Now, timely data are sent to tsunami warning centers in 13 countries, as well as to civil aviation authorities and nuclear regulators. This glasnost is due in large part to Lassina Zerbo, director of CTBTO's International Data Centre from 2004 to 2013 and, since then, the organization's executive secretary. Zerbo spoke with Science for this Q&A on the eve of the 5th CTBT Science and Technology Conference. Author: Daniel Clery
      Keywords: Q&A
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1410
       
  • [Feature] The cancer test
    • Authors: Jocelyn Kaiser
      Abstract: In the fall of 2013, emails arrived in the inboxes of dozens of scientists informing that their work had been chosen for scrutiny by a project aiming to replicate 50 high-impact cancer biology papers. The Reproducibility Project: Cancer Biology, an ambitious, open-science effort to test whether key findings in top journals can be reproduced by independent labs, has stirred concerns in the community. Almost every scientist targeted by the project who spoke with Science agrees that studies in cancer biology, as in many other fields, too often turn out to be irreproducible. But few feel comfortable with this particular effort, which plans to announce its findings in coming months. Leaders of the project say it will ultimately benefit the field by gauging the extent of the reproducibility problem in cancer biology. Author: Jocelyn Kaiser
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1411
       
  • [In Depth] Surviving Ebola survival
    • Authors: Kai Kupferschmidt
      Abstract: More than 16,000 people have survived the Ebola outbreak in West Africa, the biggest in history. While the virus is still spreading in parts of Guinea and Sierra Leone, some scientists are turning their attention to these survivors. Many of them report symptoms ranging from hearing loss and eye problems to fatigue and erectile dysfunction. In a joint effort, the Liberian ministry of health and the U.S. National Institute of Allergy and Infectious Diseases are investigating how many people are suffering from this "post-Ebola syndrome" and what might cause it. A similar study is going on in Guinea. Investigators also hope to find out whether there is a chance that some survivors might still transmit the virus to others. Ebola virus has been found in the semen of one survivor and the eye of another months after it had been cleared from the blood. Author: Kai Kupferschmidt
      Keywords: Infectious Diseases
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1406
       
  • [In Depth] An enhanced view of gene control
    • Authors: Elizabeth Pennisi
      Abstract: Although researchers have scrutinized genes as if they were Hollywood celebrities, the stretches of regulatory DNA called enhancers have largely stayed in the background, their workings a mystery. A recent genetics meeting signaled a change: In talk after talk, researchers described where and how these quiet fixers exert their influence. One group showed how enhancers maintain the right level of sensitivity to other signals, so that they switch on genes only at the right times and places. Others explored how cells package genes and their enhancers so that they can work together properly, and how DNA forms loops that bring enhancers right to the target gene. The advances even point to strategies for exploiting these regulatory elements to treat disease, by switching off disease genes and turning up the activity of healthy ones. Author: Elizabeth Pennisi
      Keywords: Genetics
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1407
       
  • [Editorial] Solving reproducibility
    • Authors: Stuart Buck
      Abstract: The reproducibility problem in science is a familiar issue, not only within the scientific community, but with the general public as well. Recent developments in social psychology (such as fraudulent research by D. Stapel) and cell biology (the Amgen Inc. and Bayer AG reports on how rarely they could reproduce published results) have become widely known. Nearly every field is affected, from clinical trials and neuroimaging, to economics and computer science. Obvious solutions include more research on statistical and behavioral fixes for irreproducibility, activism for policy changes, and demanding more pre-registration and data sharing from grantees. Two Perspectives in this issue (pp. 1420 and 1422) describe how journals and academic institutions can foster a culture of reproducibility. Transparency is central to improving reproducibility, but it is expensive and time-consuming. What can be done to alleviate those obstacles? Author: Stuart Buck
      PubDate: 2015-06-26
      DOI: 10.1126/science.aac8041
       
  • [In Brief] This week's section
    • Abstract: In science news around the world, DNA sequencing shows that the 8500-year-old Kennewick Man was Native American, experts with the International Whaling Commission again conclude that Japan's lethal research whaling program isn't scientifically justified, astronomers decide to restart construction of the Thirty Meter Telescope on Hawaii's Mauna Kea, a clinical trial of a promising Ebola drug in Sierra Leone is halted early after it fails to show a benefit to patients, and more. Also, the invasive, predatory New Guinea flatworm is found on the U.S. mainland for the first time. And vulture populations in Africa have plummeted over the past 3 decades, due primarily to farmers poisoning carcasses to target lions or hyenas.
      PubDate: 2015-06-26
      DOI: 10.1126/science.348.6242.1404
       
 
 
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