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https://www.readbyqxmd.com/read/27903762/a-comprehensive-nuclear-test-ban
#1
EDITORIAL
Ernest J Moniz
No abstract text is available yet for this article.
November 30, 2016: Science
https://www.readbyqxmd.com/read/27884940/ecological-speciation-of-bacteriophage-lambda-in-allopatry-and-sympatry
#2
Justin R Meyer, Devin T Dobias, Sarah J Medina, Lisa Servilio, Animesh Gupta, Richard E Lenski
Understanding the conditions that allow speciation to occur is difficult because most research has focused on either long-lived organisms or asexual microorganisms. We propagated bacteriophage λ, a virus with rapid generations and frequent recombination, on two Escherichia coli host genotypes that expressed either the LamB or OmpF receptor. When supplied with either single host (allopatry), λ improved its binding to the available receptor while losing its ability to use the alternative. When evolving on both hosts together (sympatry), the viruses split into two lineages with divergent receptor preferences...
November 24, 2016: Science
https://www.readbyqxmd.com/read/27884939/regulation-of-sugar-transporter-activity-for-antibacterial-defense-in-arabidopsis
#3
Kohji Yamada, Yusuke Saijo, Hirofumi Nakagami, Yoshitaka Takano
Microbial pathogens strategically acquire metabolites from their hosts during infection. Here we show that the host can intervene to prevent such metabolite loss to pathogens. Phosphorylation-dependent regulation of sugar transporter 13 (STP13) is required for antibacterial defense in the plant Arabidopsis thaliana STP13 physically associates with the flagellin receptor flagellin-sensitive 2 (FLS2) and its co-receptor BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1 (BAK1). BAK1 phosphorylates STP13 at threonine 485, which enhances its monosaccharide uptake activity to compete with bacteria for extracellular sugars...
November 24, 2016: Science
https://www.readbyqxmd.com/read/27856850/fault-activation-by-hydraulic-fracturing-in-western-canada
#4
Xuewei Bao, David W Eaton
Hydraulic fracturing has been inferred to trigger the majority of injection-induced earthquakes in western Canada, in contrast to the midwestern United States where massive saltwater disposal is the dominant triggering mechanism. A template-based earthquake catalog from a seismically active Canadian shale play, combined with comprehensive injection data during a 4-month interval, shows that earthquakes are tightly clustered in space and time near hydraulic fracturing sites. The largest event [moment magnitude (MW) 3...
November 17, 2016: Science
https://www.readbyqxmd.com/read/27856849/rosetta-s-comet-67p-churyumov-gerasimenko-sheds-its-dusty-mantle-to-reveal-its-icy-nature
#5
S Fornasier, S Mottola, H U Keller, M A Barucci, B Davidsson, C Feller, J D P Deshapriya, H Sierks, C Barbieri, P L Lamy, R Rodrigo, D Koschny, H Rickman, M A'Hearn, J Agarwal, J-L Bertaux, I Bertini, S Besse, G Cremonese, V Da Deppo, S Debei, M De Cecco, J Deller, M R El-Maarry, M Fulle, O Groussin, P J Gutierrez, C Güttler, M Hofmann, S F Hviid, W-H Ip, L Jorda, J Knollenberg, G Kovacs, R Kramm, E Kührt, M Küppers, M L Lara, M Lazzarin, J J Lopez Moreno, F Marzari, M Massironi, G Naletto, N Oklay, M Pajola, A Pommerol, F Preusker, F Scholten, X Shi, N Thomas, I Toth, C Tubiana, J-B Vincent
The Rosetta spacecraft has investigated comet 67P/Churyumov-Gerasimenko from large heliocentric distances to its perihelion passage and beyond. We trace the seasonal and diurnal evolution of the colors of the 67P nucleus, finding changes driven by sublimation and recondensation of water ice. The whole nucleus became relatively bluer near perihelion, as increasing activity removed the surface dust, implying that water ice is widespread underneath the surface. We identified large (1500 m(2)) ice-rich patches appearing and then vanishing in about 10 days, indicating small-scale heterogeneities on the nucleus...
November 17, 2016: Science
https://www.readbyqxmd.com/read/27856848/how-boundaries-shape-chemical-delivery-in-microfluidics
#6
Manuchehr Aminian, Francesca Bernardi, Roberto Camassa, Daniel M Harris, Richard M McLaughlin
Many microfluidic systems including chemical reaction, sample analysis, separation, chemotaxis, and drug development and injection, require control and precision of solute transport. While concentration levels are easily specified at injection, pressure-driven transport through channels is known to spread the initial distribution resulting in reduced concentrations downstream. Here, we document an unexpected phenomenon: the channel's cross-sectional aspect ratio alone can control the shape of the concentration profile along the channel length...
November 17, 2016: Science
https://www.readbyqxmd.com/read/27856847/ultrafine-jagged-platinum-nanowires-enable-ultrahigh-mass-activity-for-the-oxygen-reduction-reaction
#7
Mufan Li, Zipeng Zhao, Tao Cheng, Alessandro Fortunelli, Chih-Yen Chen, Rong Yu, Qinghua Zhang, Lin Gu, Boris Merinov, Zhaoyang Lin, Enbo Zhu, Ted Yu, Qingying Jia, Jinghua Guo, Liang Zhang, William A Goddard, Yu Huang, Xiangfeng Duan
Improving the platinum (Pt) mass activity for the oxygen reduction reaction (ORR) should optimize both the specific activity and the electrochemical active surface area (ECSA). We show solution-synthesized Pt/NiO core/shell nanowires can be converted into PtNi alloy nanowires through a thermal annealing process, and then transformed into jagged Pt nanowires via an electrochemical dealloying. The jagged nanowires exhibit an ECSA of 118 m(2) per gram Pt and a specific activity of 11.5 mA per square centimeter for ORR (at 0...
November 17, 2016: Science
https://www.readbyqxmd.com/read/27856846/seasonal-exposure-of-carbon-dioxide-ice-on-the-nucleus-of-comet-67p-churyumov-gerasimenko
#8
G Filacchione, A Raponi, F Capaccioni, M Ciarniello, F Tosi, M T Capria, M C De Sanctis, A Migliorini, G Piccioni, P Cerroni, M A Barucci, S Fornasier, B Schmitt, E Quirico, S Erard, D Bockelee-Morvan, C Leyrat, G Arnold, V Mennella, E Ammannito, G Bellucci, J Benkhoff, J P Bibring, A Blanco, M I Blecka, R Carlson, U Carsenty, L Colangeli, M Combes, M Combi, J Crovisier, P Drossart, T Encrenaz, C Federico, U Fink, S Fonti, M Fulchignoni, W H Ip, P Irwin, R Jaumann, E Kuehrt, Y Langevin, G Magni, T McCord, L Moroz, S Mottola, E Palomba, U Schade, K Stephan, F Taylor, D Tiphene, G P Tozzi, P Beck, N Biver, L Bonal, J-Ph Combe, D Despan, E Flamini, M Formisano, A Frigeri, D Grassi, M S Gudipati, D Kappel, A Longobardo, F Mancarella, K Markus, F Merlin, R Orosei, G Rinaldi, M Cartacci, A Cicchetti, Y Hello, F Henry, S Jacquinod, J M Reess, R Noschese, R Politi, G Peter
Carbon dioxide is one of the most abundant species in cometary nuclei, but due to its high volatility CO2 ice is generally only found beneath the surface. We report the infrared spectroscopic identification of a CO2 ice-rich surface area, located in the Anhur region of comet 67P/Churyumov-Gerasimenko. Spectral modeling shows that about 0.1% of the 80×60 m area is CO2 ice. This exposed ice was observed a short time after exiting from local winter; following the increased illumination, the CO2 ice completely disappeared over about three weeks...
November 17, 2016: Science
https://www.readbyqxmd.com/read/27856845/what-now-for-science
#9
EDITORIAL
Rush Holt
No abstract text is available yet for this article.
November 17, 2016: Science
https://www.readbyqxmd.com/read/27856844/the-magnetic-field-and-turbulence-of-the-cosmic-web-measured-using-a-brilliant-fast-radio-burst
#10
V Ravi, R M Shannon, M Bailes, K Bannister, S Bhandari, N D R Bhat, S Burke-Spolaor, M Caleb, C Flynn, A Jameson, S Johnston, E F Keane, M Kerr, C Tiburzi, A V Tuntsov, H K Vedantham
Fast radio bursts (FRBs) are millisecond-duration events thought to originate beyond the Milky Way galaxy. Uncertainty surrounding the burst sources, and their propagation through intervening plasma, has limited their use as cosmological probes. We report on a mildly dispersed (dispersion measure 266.5 ± 0.1 pc cm(-3)), exceptionally intense (120 ± 30 Jy), linearly polarized, scintillating burst (FRB 150807) that we directly localize to 9 arcmin(2) Based on a low Faraday rotation (12.0 ± 0.7 rad m(-2)), we infer negligible magnetization in the circum-burst plasma and constrain the net magnetization of the cosmic web along this sightline to <21 nG, parallel to the line-of-sight...
November 17, 2016: Science
https://www.readbyqxmd.com/read/27811285/an-atom-by-atom-assembler-of-defect-free-arbitrary-2d-atomic-arrays
#11
Daniel Barredo, Sylvain de Léséleuc, Vincent Lienhard, Thierry Lahaye, Antoine Browaeys
Large arrays of individually controlled atoms trapped in optical tweezers are a very promising platform for quantum engineering applications. However, deterministic loading of the traps is experimentally challenging. Here, we demonstrate the preparation of fully loaded, two-dimensional arrays of up to ~50 microtraps each containing a single atom, and arranged in arbitrary geometries. Starting from initially larger, half-filled matrices of randomly loaded traps, we obtain user-defined target arrays at unit filling...
November 3, 2016: Science
https://www.readbyqxmd.com/read/27811284/atom-by-atom-assembly-of-defect-free-one-dimensional-cold-atom-arrays
#12
Manuel Endres, Hannes Bernien, Alexander Keesling, Harry Levine, Eric R Anschuetz, Alexandre Krajenbrink, Crystal Senko, Vladan Vuletic, Markus Greiner, Mikhail D Lukin
The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a platform for the deterministic preparation of regular one-dimensional arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 milliseconds. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir...
November 3, 2016: Science
https://www.readbyqxmd.com/read/27789799/the-epigenetic-landscape-of-t-cell-exhaustion
#13
Debattama R Sen, James Kaminski, R Anthony Barnitz, Makoto Kurachi, Ulrike Gerdemann, Kathleen B Yates, Hsiao-Wei Tsao, Jernej Godec, Martin W LaFleur, Flavian D Brown, Pierre Tonnerre, Raymond T Chung, Damien C Tully, Todd M Allen, Nicole Frahm, Georg M Lauer, E John Wherry, Nir Yosef, W Nicholas Haining
Exhausted T cells in cancer and chronic viral infection express distinctive patterns of genes, including sustained expression of programmed cell death protein 1 (PD-1). However, the regulation of gene expression in exhausted T cells is poorly understood. Here, we define the accessible chromatin landscape in exhausted CD8(+) T cells and show that it is distinct from functional memory CD8(+) T cells. Exhausted CD8(+) T cells in humans and a mouse model of chronic viral infection acquire a state-specific epigenetic landscape organized into functional modules of enhancers...
October 27, 2016: Science
https://www.readbyqxmd.com/read/27789798/phytochrome-b-integrates-light-and-temperature-signals-in-arabidopsis
#14
Martina Legris, Cornelia Klose, E Sethe Burgie, Cecilia Costigliolo, Maximiliano Neme, Andreas Hiltbrunner, Philip A Wigge, Eberhard Schäfer, Richard D Vierstra, Jorge J Casal
Ambient temperature regulates many aspects of plant growth and development but its sensors are unknown. Here, we demonstrate that the phytochrome B (phyB) photoreceptor participates in temperature perception through its temperature-dependent reversion from the active Pfr state to the inactive Pr state. Increased rates of thermal reversion upon exposing Arabidopsis seedlings to warm environments reduce both the abundance of the biologically active Pfr-Pfr dimer pool of phyB and the size of the associated nuclear bodies, even in daylight...
October 27, 2016: Science
https://www.readbyqxmd.com/read/27789796/global-atmospheric-particle-formation-from-cern-cloud-measurements
#15
Eimear M Dunne, Hamish Gordon, Andreas Kürten, João Almeida, Jonathan Duplissy, Christina Williamson, Ismael K Ortega, Kirsty J Pringle, Alexey Adamov, Urs Baltensperger, Peter Barmet, Francois Benduhn, Federico Bianchi, Martin Breitenlechner, Antony Clarke, Joachim Curtius, Josef Dommen, Neil M Donahue, Sebastian Ehrhart, Richard C Flagan, Alessandro Franchin, Roberto Guida, Jani Hakala, Armin Hansel, Martin Heinritzi, Tuija Jokinen, Juha Kangasluoma, Jasper Kirkby, Markku Kulmala, Agnieszka Kupc, Michael J Lawler, Katrianne Lehtipalo, Vladimir Makhmutov, Graham Mann, Serge Mathot, Joonas Merikanto, Pasi Miettinen, Athanasios Nenes, Antti Onnela, Alexandru Rap, Carly L S Reddington, Francesco Riccobono, Nigel A D Richards, Matti P Rissanen, Linda Rondo, Nina Sarnela, Siegfried Schobesberger, Kamalika Sengupta, Mario Simon, Mikko Sipilä, James N Smith, Yuri Stozkhov, Antonio Tomé, Jasmin Tröstl, Paul E Wagner, Daniela Wimmer, Paul M Winkler, Douglas R Worsnop, Kenneth S Carslaw
Fundamental questions remain about the origin of newly formed atmospheric aerosol particles because data from laboratory measurements have been insufficient to build global models. In contrast, gas-phase chemistry models have been based on laboratory kinetics measurements for decades. Here we build a global model of aerosol formation using extensive laboratory-measured nucleation rates involving sulfuric acid, ammonia, ions and organic compounds. The simulations and a comparison with atmospheric observations show that nearly all nucleation throughout the present-day atmosphere involves ammonia or biogenic organic compounds in addition to sulfuric acid...
October 27, 2016: Science
https://www.readbyqxmd.com/read/27789795/epigenetic-stability-of-exhausted-t-cells-limits-durability-of-reinvigoration-by-pd-1-blockade
#16
Kristen E Pauken, Morgan A Sammons, Pamela M Odorizzi, Sasikanth Manne, Jernej Godec, Omar Khan, Adam M Drake, Zeyu Chen, Debattama Sen, Makoto Kurachi, R Anthony Barnitz, Caroline Bartman, Bertram Bengsch, Alexander C Huang, Jason M Schenkel, Golnaz Vahedi, W Nicholas Haining, Shelley L Berger, E John Wherry
Blocking PD-1 can re-invigorate exhausted CD8 T cells (TEX) and improve control of chronic infections and cancer. However, whether blocking PD-1 can reprogram TEX into durable memory T cells (TMEM) is unclear. We found that re-invigoration of TEX in mice by PD-L1 blockade caused minimal memory development. After blockade, re-invigorated TEX became re-exhausted if antigen remained high, and failed to become TMEM upon antigen clearance. TEX acquired an epigenetic profile distinct from effector (TEFF) and TMEM cells that was minimally remodeled following PD-L1 blockade...
October 27, 2016: Science
https://www.readbyqxmd.com/read/27738017/microresonator-soliton-dual-comb-spectroscopy
#17
Myoung-Gyun Suh, Qi-Fan Yang, Ki Youl Yang, Xu Yi, Kerry J Vahala
Rapid characterization of optical and vibrational spectra with high resolution can identify species in cluttered environments and is important for assays and early alerts. Dual-comb spectroscopy has emerged as a powerful approach to acquire nearly instantaneous Raman and optical spectra with unprecedented resolution. Spectra are generated directly in the electrical domain and avoid bulky mechanical spectrometers. We demonstrate a miniature soliton-based dual-comb system that can potentially transfer the approach to a chip platform...
October 13, 2016: Science
https://www.readbyqxmd.com/read/27738014/an-integrated-diamond-nanophotonics-platform-for-quantum-optical-networks
#18
A Sipahigil, R E Evans, D D Sukachev, M J Burek, J Borregaard, M K Bhaskar, C T Nguyen, J L Pacheco, H A Atikian, C Meuwly, R M Camacho, F Jelezko, E Bielejec, H Park, M Lončar, M D Lukin
Efficient interfaces between photons and quantum emitters form the basis for quantum networks and enable optical nonlinearities at the single-photon level. We demonstrate an integrated platform for scalable quantum nanophotonics based on silicon-vacancy (SiV) color centers coupled to diamond nanodevices. By placing SiV centers inside diamond photonic crystal cavities, we realize a quantum-optical switch controlled by a single color center. We control the switch using SiV metastable states and observe optical switching at the single-photon level...
October 13, 2016: Science
https://www.readbyqxmd.com/read/27738013/super-dry-reforming-of-methane-intensifies-co2-utilization-via-le-chatelier-s-principle
#19
Lukas C Buelens, Vladimir V Galvita, Hilde Poelman, Christophe Detavernier, Guy B Marin
Efficient CO2 transformation from a waste product to carbon source for chemicals and fuels will require reaction conditions that effect its reduction. We develop a "super-dry" CH4 reforming reaction for enhanced CO production from CH4 and CO2 We used Ni/MgAl2O4 as a CH4 reforming catalyst, Fe2O3/MgAl2O4 as a solid oxygen carrier, and CaO/Al2O3 as a CO2 sorbent. The isothermal coupling of these three different processes resulted in higher CO production compared with conventional dry reforming by avoiding back reactions with water...
October 13, 2016: Science
https://www.readbyqxmd.com/read/27738012/self-renewal-of-a-purified-tie2-hematopoietic-stem-cell-population-relies-on-mitochondrial-clearance
#20
Kyoko Ito, Raphaël Turcotte, Jinhua Cui, Samuel E Zimmerman, Sandra Pinho, Toshihide Mizoguchi, Fumio Arai, Judith M Runnels, Clemens Alt, Julie Teruya-Feldstein, Jessica C Mar, Rajat Singh, Toshio Suda, Charles P Lin, Paul S Frenette, Keisuke Ito
A single hematopoietic stem cell (HSC) is capable of reconstituting hematopoiesis and maintaining homeostasis by balancing self-renewal and cell differentiation. The mechanisms of HSC division balance, however, are not yet defined. Here we demonstrate, by characterizing at the single cell level a purified and minimally heterogeneous Tie2(+) HSC population, that these top hierarchical HSCs preferentially undergo symmetric divisions. The induction of mitophagy, a quality-control process in mitochondria, plays an essential role in self-renewing expansion of Tie2(+) HSCs...
October 13, 2016: Science
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