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Journal Cover Science     [SJR: 10.618]   [H-I: 739]
   [2013 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  [3 journals]
  • [Special Issue Report] Time variability and heterogeneity in the coma of
           67P/Churyumov-Gerasimenko
    • Authors: M. Hässig
      Abstract: Comets contain the best-preserved material from the beginning of our planetary system. Their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft has measured the coma composition of comet 67P/Churyumov-Gerasimenko with well-sampled time resolution per rotation. Measurements were made over many comet rotation periods and a wide range of latitudes. These measurements show large fluctuations in composition in a heterogeneous coma that has diurnal and possibly seasonal variations in the major outgassing species: water, carbon monoxide, and carbon dioxide. These results indicate a complex coma-nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface.
      Authors : M. Hässig, K. Altwegg, H. Balsiger, A. Bar-Nun, J. J. Berthelier, A. Bieler, P. Bochsler, C. Briois, U. Calmonte, M. Combi, J. De Keyser, P. Eberhardt, B. Fiethe, S. A. Fuselier, M. Galand, S. Gasc, T. I. Gombosi, K. C. Hansen, A. Jäckel, H. U. Keller, E. Kopp, A. Korth, E. Kührt, L. Le Roy, U. Mall, B. Marty, O. Mousis, E. Neefs, T. Owen, H. Rème, M. Rubin, T. Sémon, C. Tornow, C.-Y. Tzou, J. H. Waite, P. Wurz
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa0276
       
  • [In Depth] Surveys reveal state of Afghan population
    • Authors: Mara Hvistendahl
      Abstract: A slew of new surveys are illuminating demographics in insecure Afghanistan, after decades in which many key population indicators were a mystery. The Socio-Demographic and Economic Survey, a province-by-province count of households carried out by the Afghan Central Statistics Organization with assistance from the United Nations Population Fund, is now under way, and plans for still more ambitious surveys are being rolled out as well. Such projects follow on more limited assessments of fertility, mortality, and other factors. Worsening security concerns are an issue; surveyors now routinely avoid Taliban-controlled parts of the rural south. But even partial results are a boon to researchers, government officials, and aid agencies once starved for data. Author: Mara Hvistendahl
      Keywords: Demography
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.359
       
  • [In Depth] Comet close-up reveals a world of surprises
    • Authors: Eric Hand
      Abstract: When Europe's Rosetta spacecraft started studying comet 67P/Churyumov-Gerasimenko late in 2014, some scientists feared the comet might turn out to be a boring lump of ice and dust. They needn't have worried. Papers in this issue of Science show that 67P is pocked with pits, incised by cracks and cliffs, and decorated with ripples and flows of dust—all signs of an extraordinarily active place. Many of the intriguing landforms testify to the power of the sun, which heats up 67P during part of every orbit, igniting jets of gas and dust that resculpt the surface of the comet. Other discoveries could be primordial, dating from the comet's formation more than 4.5 billion years ago. Mission scientists say the complexity of the comet suggests that the comet-forming regions of the early solar system were more turbulent and chemically diverse than theorists have thought. Author: Eric Hand
      Keywords: Planetary Science
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.358
       
  • [Editorial] Rethink the Nicaragua Canal
    • Authors: Jorge A. Huete-Perez
      Abstract: At the end of 2014, construction began on the Grand Canal in Nicaragua, a project shrouded in secrecy since its inception 2.5 years ago. The Nicaraguan government showed scant evidence of having accounted for the impact on the environment and on local residents, or of having adequately consulted the public in selecting the final 278-km route. Such disregard should be alarming to everyone. Projects of this magnitude warrant dialogue among all stakeholders. As construction is projected to span 5 years, there is still time to reconsider it and convene independent assessments and meetings that are transparent, inclusive, and respectful of different perspectives, to guide the project toward the best outcome.
      Authors : Jorge A. Huete-Perez, Axel Meyer, Pedro J. Alvarez
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa6998
       
  • [In Brief] This week's section
    • Abstract: In science news around the world, a federal judge rules that BP spilled 3.19 million barrels of oil into the Gulf of Mexico during the 2010 Deepwater Horizon disaster, NASA's Mars Reconnaissance Orbiter spots the long-lost Beagle 2 probe on the Red Planet, Australian environmentalists take the country's environment minister to court over his approval last year of a coal mine, the U.S. National Institute of General Medical Sciences imposes a one-grant limit on scientists who already have plentiful support, and the Next-Generation Transit Survey observatory in Chile gains first light. Also, a grassroots plan to save monarch butterflies by planting milkweed backfires. And a veteran Indian space engineer is tapped to head the Indian Space Research Organisation.
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.356
       
  • [Special Issue Research Article] Dust measurements in the coma of comet
           67P/Churyumov-Gerasimenko inbound to the Sun
    • Authors: Alessandra Rotundi
      Abstract:
      Authors : Alessandra Rotundi, Holger Sierks, Vincenzo Della Corte, Marco Fulle, Pedro J. Gutierrez, Luisa Lara, Cesare Barbieri, Philippe L. Lamy, Rafael Rodrigo, Detlef Koschny, Hans Rickman, Horst Uwe Keller, José J. López-Moreno, Mario Accolla, Jessica Agarwal, Michael F. A’Hearn, Nicolas Altobelli, Francesco Angrilli, M. Antonietta Barucci, Jean-Loup Bertaux, Ivano Bertini, Dennis Bodewits, Ezio Bussoletti, Luigi Colangeli, Massimo Cosi, Gabriele Cremonese, Jean-Francois Crifo, Vania Da Deppo, Björn Davidsson, Stefano Debei, Mariolino De Cecco, Francesca Esposito, Marco Ferrari, Sonia Fornasier, Frank Giovane, Bo Gustafson, Simon F. Green, Olivier Groussin, Eberhard Grün, Carsten Güttler, Miguel L. Herranz, Stubbe F. Hviid, Wing Ip, Stavro Ivanovski, José M. Jerónimo, Laurent Jorda, Joerg Knollenberg, Rainer Kramm, Ekkehard Kührt, Michael Küppers, Monica Lazzarin, Mark R. Leese, Antonio C. López-Jiménez, Francesca Lucarelli, Stephen C. Lowry, Francesco Marzari, Elena Mazzotta Epifani, J. Anthony M. McDonnell, Vito Mennella, Harald Michalik, Antonio Molina, Rafael Morales, Fernando Moreno, Stefano Mottola, Giampiero Naletto, Nilda Oklay, José L. Ortiz, Ernesto Palomba, Pasquale Palumbo, Jean-Marie Perrin, Julio Rodríguez, Lola Sabau, Colin Snodgrass, Roberto Sordini, Nicolas Thomas, Cecilia Tubiana, Jean-Baptiste Vincent, Paul Weissman, Klaus-Peter Wenzel, Vladimir Zakharov, John C. Zarnecki
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa3905
       
  • [Special Issue Research Article] On the nucleus structure and activity of
           comet 67P/Churyumov-Gerasimenko
    • Authors: Holger Sierks
      Abstract: Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.
      Authors : Holger Sierks, Cesare Barbieri, Philippe L. Lamy, Rafael Rodrigo, Detlef Koschny, Hans Rickman, Horst Uwe Keller, Jessica Agarwal, Michael F. A’Hearn, Francesco Angrilli, Anne-Therese Auger, M. Antonella Barucci, Jean-Loup Bertaux, Ivano Bertini, Sebastien Besse, Dennis Bodewits, Claire Capanna, Gabriele Cremonese, Vania Da Deppo, Björn Davidsson, Stefano Debei, Mariolino De Cecco, Francesca Ferri, Sonia Fornasier, Marco Fulle, Robert Gaskell, Lorenza Giacomini, Olivier Groussin, Pablo Gutierrez-Marques, Pedro J. Gutiérrez, Carsten Güttler, Nick Hoekzema, Stubbe F. Hviid, Wing-Huen Ip, Laurent Jorda, Jörg Knollenberg, Gabor Kovacs, J. Rainer Kramm, Ekkehard Kührt, Michael Küppers, Fiorangela La Forgia, Luisa M. Lara, Monica Lazzarin, Cédric Leyrat, Josè J. Lopez Moreno, Sara Magrin, Simone Marchi, Francesco Marzari, Matteo Massironi, Harald Michalik, Richard Moissl, Stefano Mottola, Giampiero Naletto, Nilda Oklay, Maurizio Pajola, Marco Pertile, Frank Preusker, Lola Sabau, Frank Scholten, Colin Snodgrass, Nicolas Thomas, Cecilia Tubiana, Jean-Baptiste Vincent, Klaus-Peter Wenzel, Mirco Zaccariotto, Martin Pätzold
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa1044
       
  • [Special Issue Report] Birth of a comet magnetosphere: A spring of water
           ions
    • Authors: Hans Nilsson
      Abstract: The Rosetta mission shall accompany comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 astronomical units through perihelion passage at 1.25 astronomical units, spanning low and maximum activity levels. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation, until the size and plasma pressure of the ionized atmosphere define its boundaries: A magnetosphere is born. Using the Rosetta Plasma Consortium ion composition analyzer, we trace the evolution from the first detection of water ions to when the atmosphere begins repelling the solar wind (~3.3 astronomical units), and we report the spatial structure of this early interaction. The near-comet water population comprises accelerated ions (
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa0571
       
  • [Special Issue Report] 67P/Churyumov-Gerasimenko, a Jupiter family comet
           with a high D/H ratio
    • Authors: K. Altwegg
      Abstract: The provenance of water and organic compounds on Earth and other terrestrial planets has been discussed for a long time without reaching a consensus. One of the best means to distinguish between different scenarios is by determining the deuterium-to-hydrogen (D/H) ratios in the reservoirs for comets and Earth’s oceans. Here, we report the direct in situ measurement of the D/H ratio in the Jupiter family comet 67P/Churyumov-Gerasimenko by the ROSINA mass spectrometer aboard the European Space Agency’s Rosetta spacecraft, which is found to be (5.3 ± 0.7) × 10−4—that is, approximately three times the terrestrial value. Previous cometary measurements and our new finding suggest a wide range of D/H ratios in the water within Jupiter family objects and preclude the idea that this reservoir is solely composed of Earth ocean–like water.
      Authors : K. Altwegg, H. Balsiger, A. Bar-Nun, J. J. Berthelier, A. Bieler, P. Bochsler, C. Briois, U. Calmonte, M. Combi, J. De Keyser, P. Eberhardt, B. Fiethe, S. Fuselier, S. Gasc, T. I. Gombosi, K.C. Hansen, M. Hässig, A. Jäckel, E. Kopp, A. Korth, L. LeRoy, U. Mall, B. Marty, O. Mousis, E. Neefs, T. Owen, H. Rème, M. Rubin, T. Sémon, C.-Y. Tzou, H. Waite, P. Wurz
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261952
       
  • [Special Issue Report] The organic-rich surface of comet
           67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta
    • Authors: F. Capaccioni
      Abstract: The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ−1), and the broad absorption feature in the 2.9-to-3.6–micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.
      Authors : F. Capaccioni, A. Coradini, G. Filacchione, S. Erard, G. Arnold, P. Drossart, M. C. De Sanctis, D. Bockelee-Morvan, M. T. Capria, F. Tosi, C. Leyrat, B. Schmitt, E. Quirico, P. Cerroni, V. Mennella, A. Raponi, M. Ciarniello, T. McCord, L. Moroz, E. Palomba, E. Ammannito, M. A. Barucci, G. Bellucci, J. Benkhoff, J. P. Bibring, A. Blanco, M. Blecka, R. Carlson, U. Carsenty, L. Colangeli, M. Combes, M. Combi, J. Crovisier, T. Encrenaz, C. Federico, U. Fink, S. Fonti, W. H. Ip, P. Irwin, R. Jaumann, E. Kuehrt, Y. Langevin, G. Magni, S. Mottola, V. Orofino, P. Palumbo, G. Piccioni, U. Schade, F. Taylor, D. Tiphene, G. P. Tozzi, P. Beck, N. Biver, L. Bonal, J.-Ph. Combe, D. Despan, E. Flamini, S. Fornasier, A. Frigeri, D. Grassi, M. Gudipati, A. Longobardo, K. Markus, F. Merlin, R. Orosei, G. Rinaldi, K. Stephan, M. Cartacci, A. Cicchetti, S. Giuppi, Y. Hello, F. Henry, S. Jacquinod, R. Noschese, G. Peter, R. Politi, J. M. Reess, A. Semery
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa0628
       
  • [Special Issue Report] Subsurface properties and early activity of comet
           67P/Churyumov-Gerasimenko
    • Authors: Samuel Gulkis
      Abstract: Heat transport and ice sublimation in comets are interrelated processes reflecting properties acquired at the time of formation and during subsequent evolution. The Microwave Instrument on the Rosetta Orbiter (MIRO) acquired maps of the subsurface temperature of comet 67P/Churyumov-Gerasimenko, at 1.6 mm and 0.5 mm wavelengths, and spectra of water vapor. The total H2O production rate varied from 0.3 kg s–1 in early June 2014 to 1.2 kg s–1 in late August and showed periodic variations related to nucleus rotation and shape. Water outgassing was localized to the “neck” region of the comet. Subsurface temperatures showed seasonal and diurnal variations, which indicated that the submillimeter radiation originated at depths comparable to the diurnal thermal skin depth. A low thermal inertia (~10 to 50 J K–1 m–2 s–0.5), consistent with a thermally insulating powdered surface, is inferred.
      Authors : Samuel Gulkis, Mark Allen, Paul von Allmen, Gerard Beaudin, Nicolas Biver, Dominique Bockelée-Morvan, Mathieu Choukroun, Jacques Crovisier, Björn J. R. Davidsson, Pierre Encrenaz, Therese Encrenaz, Margaret Frerking, Paul Hartogh, Mark Hofstadter, Wing-Huen Ip, Michael Janssen, Christopher Jarchow, Stephen Keihm, Seungwon Lee, Emmanuel Lellouch, Cedric Leyrat, Ladislav Rezac, F. Peter Schloerb, Thomas Spilker
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa0709
       
  • [Special Issue Research Article] The morphological diversity of comet
           67P/Churyumov-Gerasimenko
    • Authors: Nicolas Thomas
      Abstract: Images of comet 67P/Churyumov-Gerasimenko acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) imaging system onboard the European Space Agency’s Rosetta spacecraft at scales of better than 0.8 meter per pixel show a wide variety of different structures and textures. The data show the importance of airfall, surface dust transport, mass wasting, and insolation weathering for cometary surface evolution, and they offer some support for subsurface fluidization models and mass loss through the ejection of large chunks of material.
      Authors : Nicolas Thomas, Holger Sierks, Cesare Barbieri, Philippe L. Lamy, Rafael Rodrigo, Hans Rickman, Detlef Koschny, Horst Uwe Keller, Jessica Agarwal, Michael F. A'Hearn, Francesco Angrilli, Anne-Therese Auger, M. Antonella Barucci, Jean-Loup Bertaux, Ivano Bertini, Sebastien Besse, Dennis Bodewits, Gabriele Cremonese, Vania Da Deppo, Björn Davidsson, Mariolino De Cecco, Stefano Debei, Mohamed Ramy El-Maarry, Francesca Ferri, Sonia Fornasier, Marco Fulle, Lorenza Giacomini, Olivier Groussin, Pedro J. Gutierrez, Carsten Güttler, Stubbe F. Hviid, Wing-Huen Ip, Laurent Jorda, Jörg Knollenberg, J.-Rainer Kramm, Ekkehard Kührt, Michael Küppers, Fiorangela La Forgia, Luisa M. Lara, Monica Lazzarin, Josè J. Lopez Moreno, Sara Magrin, Simone Marchi, Francesco Marzari, Matteo Massironi, Harald Michalik, Richard Moissl, Stefano Mottola, Giampiero Naletto, Nilda Oklay, Maurizio Pajola, Antoine Pommerol, Frank Preusker, Lola Sabau, Frank Scholten, Colin Snodgrass, Cecilia Tubiana, Jean-Baptiste Vincent, Klaus-Peter Wenzel
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa0440
       
  • [Business Office Feature] Overcoming challenges in cellular analysis:
           Multiparameter analysis of rare cells
    • Authors: Andrea Cossarizza
      Abstract:
      Authors : Andrea Cossarizza, David Cousins
      Keywords: Science Webinar Series
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.443-c
       
  • [Working Life] Teaming up against tsunamis
    • Authors: Elisabeth Pain
      Abstract: Author: Elisabeth Pain
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.450
       
  • [Report] A molecular census of 26S proteasomes in intact neurons
    • Authors: Shoh Asano
      Abstract: The 26S proteasome is a key player in eukaryotic protein quality control and in the regulation of numerous cellular processes. Here, we describe quantitative in situ structural studies of this highly dynamic molecular machine in intact hippocampal neurons. We used electron cryotomography with the Volta phase plate, which allowed high fidelity and nanometer precision localization of 26S proteasomes. We undertook a molecular census of single- and double-capped proteasomes and assessed the conformational states of individual complexes. Under the conditions of the experiment—that is, in the absence of proteotoxic stress—only 20% of the 26S proteasomes were engaged in substrate processing. The remainder was in the substrate-accepting ground state. These findings suggest that in the absence of stress, the capacity of the proteasome system is not fully used.
      Authors : Shoh Asano, Yoshiyuki Fukuda, Florian Beck, Antje Aufderheide, Friedrich Förster, Radostin Danev, Wolfgang Baumeister
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261197
       
  • [New Products] New Products
    • Abstract: A weekly roundup of information on newly offered instrumentation, apparatus, and laboratory materials of potential interest to researchers.
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.443-a
       
  • [Podcast] Science Podcast: 23 January Show
    • Abstract: On this week's show: Do comets have seasons? And a roundup of daily news stories.
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.443-b
       
  • [Report] Hidden costs of infection: Chronic malaria accelerates telomere
           degradation and senescence in wild birds
    • Authors: M. Asghar
      Abstract: Recovery from infection is not always complete, and mild chronic infection may persist. Although the direct costs of such infections are apparently small, the potential for any long-term effects on Darwinian fitness is poorly understood. In a wild population of great reed warblers, we found that low-level chronic malaria infection reduced life span as well as the lifetime number and quality of offspring. These delayed fitness effects of malaria appear to be mediated by telomere degradation, a result supported by controlled infection experiments on birds in captivity. The results of this study imply that chronic infection may be causing a series of small adverse effects that accumulate and eventually impair phenotypic quality and Darwinian fitness.
      Authors : M. Asghar, D. Hasselquist, B. Hansson, P. Zehtindjiev, H. Westerdahl, S. Bensch
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261121
       
  • [Report] K13-propeller mutations confer artemisinin resistance in
           Plasmodium falciparum clinical isolates
    • Authors: Judith Straimer
      Abstract: The emergence of artemisinin resistance in Southeast Asia imperils efforts to reduce the global malaria burden. We genetically modified the Plasmodium falciparum K13 locus using zinc-finger nucleases and measured ring-stage survival rates after drug exposure in vitro; these rates correlate with parasite clearance half-lives in artemisinin-treated patients. With isolates from Cambodia, where resistance first emerged, survival rates decreased from 13 to 49% to 0.3 to 2.4% after the removal of K13 mutations. Conversely, survival rates in wild-type parasites increased from ≤0.6% to 2 to 29% after the insertion of K13 mutations. These mutations conferred elevated resistance to recent Cambodian isolates compared with that of reference lines, suggesting a contemporary contribution of additional genetic factors. Our data provide a conclusive rationale for worldwide K13-propeller sequencing to identify and eliminate artemisinin-resistant parasites.
      Authors : Judith Straimer, Nina F. Gnädig, Benoit Witkowski, Chanaki Amaratunga, Valentine Duru, Arba Pramundita Ramadani, Mélanie Dacheux, Nimol Khim, Lei Zhang, Stephen Lam, Philip D. Gregory, Fyodor D. Urnov, Odile Mercereau-Puijalon, Françoise Benoit-Vical, Rick M. Fairhurst, Didier Ménard, David A. Fidock
      PubDate: 2015-01-23
      DOI: 10.1126/science.1260867
       
  • [Report] Population transcriptomics of human malaria parasites reveals the
           mechanism of artemisinin resistance
    • Authors: Sachel Mok
      Abstract: Artemisinin resistance in Plasmodium falciparum threatens global efforts to control and eliminate malaria. Polymorphisms in the kelch domain–carrying protein K13 are associated with artemisinin resistance, but the underlying molecular mechanisms are unknown. We analyzed the in vivo transcriptomes of 1043 P. falciparum isolates from patients with acute malaria and found that artemisinin resistance is associated with increased expression of unfolded protein response (UPR) pathways involving the major PROSC and TRiC chaperone complexes. Artemisinin-resistant parasites also exhibit decelerated progression through the first part of the asexual intraerythrocytic development cycle. These findings suggest that artemisinin-resistant parasites remain in a state of decelerated development at the young ring stage, whereas their up-regulated UPR pathways mitigate protein damage caused by artemisinin. The expression profiles of UPR-related genes also associate with the geographical origin of parasite isolates, further suggesting their role in emerging artemisinin resistance in the Greater Mekong Subregion.
      Authors : Sachel Mok, Elizabeth A. Ashley, Pedro E. Ferreira, Lei Zhu, Zhaoting Lin, Tomas Yeo, Kesinee Chotivanich, Mallika Imwong, Sasithon Pukrittayakamee, Mehul Dhorda, Chea Nguon, Pharath Lim, Chanaki Amaratunga, Seila Suon, Tran Tinh Hien, Ye Htut, M. Abul Faiz, Marie A. Onyamboko, Mayfong Mayxay, Paul N. Newton, Rupam Tripura, Charles J. Woodrow, Olivo Miotto, Dominic P. Kwiatkowski, François Nosten, Nicholas P. J. Day, Peter R. Preiser, Nicholas J. White, Arjen M. Dondorp, Rick M. Fairhurst, Zbynek Bozdech
      PubDate: 2015-01-23
      DOI: 10.1126/science.1260403
       
  • [Report] Composition-matched molecular “solders” for
           semiconductors
    • Authors: Dmitriy S. Dolzhnikov
      Abstract: We propose a general strategy to synthesize largely unexplored soluble chalcogenidometallates of cadmium, lead, and bismuth. These compounds can be used as “solders” for semiconductors widely used in photovoltaics and thermoelectrics. The addition of solder helped to bond crystal surfaces and link nano- or mesoscale particles together. For example, CdSe nanocrystals with Na2Cd2Se3 solder was used as a soluble precursor for CdSe films with electron mobilities exceeding 300 square centimeters per volt-second. CdTe, PbTe, and Bi2Te3 powders were molded into various shapes in the presence of a small additive of composition-matched chalcogenidometallate or chalcogel, thus opening new design spaces for semiconductor technologies.
      Authors : Dmitriy S. Dolzhnikov, Hao Zhang, Jaeyoung Jang, Jae Sung Son, Matthew G. Panthani, Tomohiro Shibata, Soma Chattopadhyay, Dmitri V. Talapin
      PubDate: 2015-01-23
      DOI: 10.1126/science.1260501
       
  • [Report] Shock compression of stishovite and melting of silica at
           planetary interior conditions
    • Authors: M. Millot
      Abstract: Deep inside planets, extreme density, pressure, and temperature strongly modify the properties of the constituent materials. In particular, how much heat solids can sustain before melting under pressure is key to determining a planet’s internal structure and evolution. We report laser-driven shock experiments on fused silica, α-quartz, and stishovite yielding equation-of-state and electronic conductivity data at unprecedented conditions and showing that the melting temperature of SiO2 rises to 8300 K at a pressure of 500 gigapascals, comparable to the core-mantle boundary conditions for a 5–Earth mass super-Earth. We show that mantle silicates and core metal have comparable melting temperatures above 500 to 700 gigapascals, which could favor long-lived magma oceans for large terrestrial planets with implications for planetary magnetic-field generation in silicate magma layers deep inside such planets.
      Authors : M. Millot, N. Dubrovinskaia, A. Černok, S. Blaha, L. Dubrovinsky, D. G. Braun, P. M. Celliers, G. W. Collins, J. H. Eggert, R. Jeanloz
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261507
       
  • [Report] Tilt engineering of spontaneous polarization and magnetization
           above 300 K in a bulk layered perovskite
    • Authors: Michael J. Pitcher
      Abstract: Crystalline materials that combine electrical polarization and magnetization could be advantageous in applications such as information storage, but these properties are usually considered to have incompatible chemical bonding and electronic requirements. Recent theoretical work on perovskite materials suggested a route for combining both properties. We used crystal chemistry to engineer specific atomic displacements in a layered perovskite, (CaySr1–y)1.15Tb1.85Fe2O7, that change its symmetry and simultaneously generate electrical polarization and magnetization above room temperature. The two resulting properties are magnetoelectrically coupled as they arise from the same displacements.
      Authors : Michael J. Pitcher, Pranab Mandal, Matthew S. Dyer, Jonathan Alaria, Pavel Borisov, Hongjun Niu, John B. Claridge, Matthew J. Rosseinsky
      PubDate: 2015-01-23
      DOI: 10.1126/science.1262118
       
  • [Report] Mars methane detection and variability at Gale crater
    • Authors: Christopher R. Webster
      Abstract: Reports of plumes or patches of methane in the martian atmosphere that vary over monthly time scales have defied explanation to date. From in situ measurements made over a 20-month period by the tunable laser spectrometer of the Sample Analysis at Mars instrument suite on Curiosity at Gale crater, we report detection of background levels of atmospheric methane of mean value 0.69 ± 0.25 parts per billion by volume (ppbv) at the 95% confidence interval (CI). This abundance is lower than model estimates of ultraviolet degradation of accreted interplanetary dust particles or carbonaceous chondrite material. Additionally, in four sequential measurements spanning a 60-sol period (where 1 sol is a martian day), we observed elevated levels of methane of 7.2 ± 2.1 ppbv (95% CI), implying that Mars is episodically producing methane from an additional unknown source.
      Authors : Christopher R. Webster, Paul R. Mahaffy, Sushil K. Atreya, Gregory J. Flesch, Michael A. Mischna, Pierre-Yves Meslin, Kenneth A. Farley, Pamela G. Conrad, Lance E. Christensen, Alexander A. Pavlov, Javier Martín-Torres, María-Paz Zorzano, Timothy H. McConnochie, Tobias Owen, Jennifer L. Eigenbrode, Daniel P. Glavin, Andrew Steele, Charles A. Malespin, P. Douglas Archer, Brad Sutter, Patrice Coll, Caroline Freissinet, Christopher P. McKay, John E. Moores, Susanne P. Schwenzer, John C. Bridges, Rafael Navarro-Gonzalez, Ralf Gellert, Mark T. Lemmon,
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261713
       
  • [Report] The exceptionally powerful TeV γ-ray emitters in the Large
           Magellanic Cloud
    • Abstract: The Large Magellanic Cloud, a satellite galaxy of the Milky Way, has been observed with the High Energy Stereoscopic System (H.E.S.S.) above an energy of 100 billion electron volts for a deep exposure of 210 hours. Three sources of different types were detected: the pulsar wind nebula of the most energetic pulsar known, N 157B; the radio-loud supernova remnant N 132D; and the largest nonthermal x-ray shell, the superbubble 30 Dor C. The unique object SN 1987A is, unexpectedly, not detected, which constrains the theoretical framework of particle acceleration in very young supernova remnants. These detections reveal the most energetic tip of a γ-ray source population in an external galaxy and provide via 30 Dor C the unambiguous detection of γ-ray emission from a superbubble. Author:
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261313
       
  • [Report] The imprint of atmospheric evolution in the D/H of Hesperian clay
           minerals on Mars
    • Authors: P. R. Mahaffy
      Abstract: The deuterium-to-hydrogen (D/H) ratio in strongly bound water or hydroxyl groups in ancient martian clays retains the imprint of the water of formation of these minerals. Curiosity’s Sample Analysis at Mars (SAM) experiment measured thermally evolved water and hydrogen gas released between 550° and 950°C from samples of Hesperian-era Gale crater smectite to determine this isotope ratio. The D/H value is 3.0 (±0.2) times the ratio in standard mean ocean water. The D/H ratio in this ~3-billion-year-old mudstone, which is half that of the present martian atmosphere but substantially higher than that expected in very early Mars, indicates an extended history of hydrogen escape and desiccation of the planet.
      Authors : P. R. Mahaffy, C. R. Webster, J. C. Stern, A. E. Brunner, S. K. Atreya, P. G. Conrad, S. Domagal-Goldman, J. L. Eigenbrode, G. J. Flesch, L. E. Christensen, H. B. Franz, C. Freissinet, D. P. Glavin, J. P. Grotzinger, J. H. Jones, L. A. Leshin, C. Malespin, A. C. McAdam, D. W. Ming, R. Navarro-Gonzalez, P. B. Niles, T. Owen, A. A. Pavlov, A. Steele, M. G. Trainer, K. H. Williford, J. J. Wray,
      PubDate: 2015-01-23
      DOI: 10.1126/science.1260291
       
  • [Research Article] Human-like hand use in Australopithecus africanus
    • Authors: Matthew M. Skinner
      Abstract: The distinctly human ability for forceful precision and power “squeeze” gripping is linked to two key evolutionary transitions in hand use: a reduction in arboreal climbing and the manufacture and use of tools. However, it is unclear when these locomotory and manipulative transitions occurred. Here we show that Australopithecus africanus (~3 to 2 million years ago) and several Pleistocene hominins, traditionally considered not to have engaged in habitual tool manufacture, have a human-like trabecular bone pattern in the metacarpals consistent with forceful opposition of the thumb and fingers typically adopted during tool use. These results support archaeological evidence for stone tool use in australopiths and provide morphological evidence that Pliocene hominins achieved human-like hand postures much earlier and more frequently than previously considered.
      Authors : Matthew M. Skinner, Nicholas B. Stephens, Zewdi J. Tsegai, Alexandra C. Foote, N. Huynh Nguyen, Thomas Gross, Dieter H. Pahr, Jean-Jacques Hublin, Tracy L. Kivell
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261735
       
  • [Research Article] Functional heterogeneity of human memory CD4+ T cell
           clones primed by pathogens or vaccines
    • Authors: Simone Becattini
      Abstract: Distinct types of CD4+ T cells protect the host against different classes of pathogens. However, it is unclear whether a given pathogen induces a single type of polarized T cell. By combining antigenic stimulation and T cell receptor deep sequencing, we found that human pathogen- and vaccine-specific T helper 1 (TH1), TH2, and TH17 memory cells have different frequencies but comparable diversity and comprise not only clones polarized toward a single fate, but also clones whose progeny have acquired multiple fates. Single naïve T cells primed by a pathogen in vitro could also give rise to multiple fates. Our results unravel an unexpected degree of interclonal and intraclonal functional heterogeneity of the human T cell response and suggest that polarized responses result from preferential expansion rather than priming.
      Authors : Simone Becattini, Daniela Latorre, Federico Mele, Mathilde Foglierini, Corinne De Gregorio, Antonino Cassotta, Blanca Fernandez, Sander Kelderman, Ton N. Schumacher, Davide Corti, Antonio Lanzavecchia, Federica Sallusto
      PubDate: 2015-01-23
      DOI: 10.1126/science.1260668
       
  • [Research Article] Tissue-based map of the human proteome
    • Authors: Mathias Uhlén
      Abstract: Resolving the molecular details of proteome variation in the different tissues and organs of the human body will greatly increase our knowledge of human biology and disease. Here, we present a map of the human tissue proteome based on an integrated omics approach that involves quantitative transcriptomics at the tissue and organ level, combined with tissue microarray–based immunohistochemistry, to achieve spatial localization of proteins down to the single-cell level. Our tissue-based analysis detected more than 90% of the putative protein-coding genes. We used this approach to explore the human secretome, the membrane proteome, the druggable proteome, the cancer proteome, and the metabolic functions in 32 different tissues and organs. All the data are integrated in an interactive Web-based database that allows exploration of individual proteins, as well as navigation of global expression patterns, in all major tissues and organs in the human body.
      Authors : Mathias Uhlén, Linn Fagerberg, Björn M. Hallström, Cecilia Lindskog, Per Oksvold, Adil Mardinoglu, Åsa Sivertsson, Caroline Kampf, Evelina Sjöstedt, Anna Asplund, IngMarie Olsson, Karolina Edlund, Emma Lundberg, Sanjay Navani, Cristina Al-Khalili Szigyarto, Jacob Odeberg, Dijana Djureinovic, Jenny Ottosson Takanen, Sophia Hober, Tove Alm, Per-Henrik Edqvist, Holger Berling, Hanna Tegel, Jan Mulder, Johan Rockberg, Peter Nilsson, Jochen M. Schwenk, Marica Hamsten, Kalle von Feilitzen, Mattias Forsberg, Lukas Persson, Fredric Johansson, Martin Zwahlen, Gunnar von Heijne, Jens Nielsen, Fredrik Pontén
      PubDate: 2015-01-23
      DOI: 10.1126/science.1260419
       
  • [Introduction to Special Issue] Rosetta begins its Comet Tale
    • Authors: M. G. G. T. Taylor
      Abstract:
      Authors : M. G. G. T. Taylor, C. Alexander, N. Altobelli, M. Fulle, M. Fulchignoni, E. Grün, P. Weissman
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa4542
       
  • [Review] Inherited landscapes and sea level change
    • Authors: Sierd Cloetingh
      Abstract: Enabled by recently gained understanding of deep-seated and surficial Earth processes, a convergence of views between geophysics and sedimentary geology has been quietly taking place over the past several decades. Surface topography resulting from lithospheric memory, retained at various temporal and spatial scales, has become the connective link between these two methodologically diverse geoscience disciplines. Ideas leading to the hypothesis of plate tectonics originated largely with an oceanic focus, where dynamic and mostly horizontal movements of the crust could be envisioned. But when these notions were applied to the landscapes of the supposedly rigid plate interiors, there was less success in explaining the observed anomalies in terrestrial topography. Solid-Earth geophysics has now reached a developmental stage where vertical movements can be measured and modeled at meaningful scales and the deep-seated structures can be imaged with increasing resolution. Concurrently, there have been advances in quantifying mechanical properties of the lithosphere (the solid outer skin of Earth, usually defined to include both the crust and the solid but elastic upper mantle above the asthenosphere). The lithosphere acts as the intermediary that transfers the effects of mantle dynamics to the surface. These developments have allowed us to better understand the previously puzzling topographic features of plate interiors and continental margins. On the sedimentary geology side, new quantitative modeling techniques and holistic approaches to integrating source-to-sink sedimentary systems have led to clearer understanding of basin evolution and sediment budgets that allow the reconstruction of missing sedimentary records and past geological landscapes.
      Authors : Sierd Cloetingh, Bilal U. Haq
      PubDate: 2015-01-23
      DOI: 10.1126/science.1258375
       
  • [This Week in Science] Volume and shape combine to find a level
    • Authors: H. Jesse Smith
      Abstract: Author: H. Jesse Smith
      Keywords: Sea Level Change
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-k
       
  • [This Week in Science] Mechanisms propelling drug resistance
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Drug Resistance
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-l
       
  • [This Week in Science] Of water and methane on Mars
    • Authors: Margaret M. Moerchen
      Abstract: Author: Margaret M. Moerchen
      Keywords: Mars Atmosphere
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-m
       
  • [This Week in Science] Tilting toward two properties
    • Authors: Phil Szuromi
      Abstract: Author: Phil Szuromi
      Keywords: Magnetic Materials
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-n
       
  • [Editors' Choice] How a mouse's nose feels the cold
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: Signal Transduction
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.385-a
       
  • [Editors' Choice] A one-two approach to air-lasing
    • Authors: Ian S. Osborne
      Abstract: Author: Ian S. Osborne
      Keywords: Optics
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.385-b
       
  • [Editors' Choice] The evolutionary benefits of warfare
    • Authors: Guy Riddihough
      Abstract: Author: Guy Riddihough
      Keywords: Anthropology
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.385-c
       
  • [Editors' Choice] A lower-mantle water cycle component
    • Authors: Brent Grocholski
      Abstract: Author: Brent Grocholski
      Keywords: Mineral Physics
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.385-d
       
  • [Editors' Choice] Droughts and dead zones on the rise
    • Authors: Nicholas S. Wigginton
      Abstract: Author: Nicholas S. Wigginton
      Keywords: Environmental Science
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.385-e
       
  • [Editors' Choice] Probing plant evolution by GC content
    • Authors: Laura M. Zahn
      Abstract: Author: Laura M. Zahn
      Keywords: Plant Genomics
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.385-f
       
  • [Editors' Choice] A cure from which there is no escape
    • Authors: Kristen L. Mueller
      Abstract: Author: Kristen L. Mueller
      Keywords: HIV Eradication
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.385-g
       
  • [This Week in Science] A light on the origin of cosmic rays
    • Authors: Margaret M. Moerchen
      Abstract: Author: Margaret M. Moerchen
      Keywords: Astrophysics
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-d
       
  • [This Week in Science] Melting silica in massive planets
    • Authors: Brent Grocholski
      Abstract: Author: Brent Grocholski
      Keywords: Planetary Science
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-e
       
  • [This Week in Science] Soldering semiconductor nanoparticles
    • Authors: Phil Szuromi
      Abstract: Author: Phil Szuromi
      Keywords: Materials Chemistry
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-f
       
  • [This Week in Science] Seeing nanostars
    • Authors: Megan Frisk
      Abstract: Author: Megan Frisk
      Keywords: Cancer Imaging
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-g
       
  • [This Week in Science] A detailed look at proteasomes in situ
    • Authors: Stella M. Hurtley
      Abstract: Author: Stella M. Hurtley
      Keywords: Proteasomes
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-h
       
  • [This Week in Science] A binding partner for an orphan receptor
    • Authors: Jason D. Berndt
      Abstract: Author: Jason D. Berndt
      Keywords: Cell Biology
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-i
       
  • [This Week in Science] Protein expression across human tissues
    • Authors: Valda Vinson
      Abstract: Author: Valda Vinson
      Keywords: Proteomics
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-j
       
  • [Books et al.] Books Received
    • Abstract: A listing of books received at Science during the week ending 16 January 2015.
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.380-b
       
  • [Letter] Carnivore coexistence: Value the wilderness
    • Authors: James J. Gilroy
      Abstract:
      Authors : James J. Gilroy, Andrés Ordiz, Richard Bischof
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.382-a
       
  • [Letter] Carnivore coexistence: America's recovery
    • Authors: Matthew E. Gompper
      Abstract:
      Authors : Matthew E. Gompper, Jerrold L. Belant, Roland Kays
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.382-b
       
  • [Letter] Carnivore coexistence: Trophic cascades
    • Authors: T. M. Newsome
      Abstract:
      Authors : T. M. Newsome, W. J. Ripple
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.383-a
       
  • [Letter] Ferns to fulfillment
    • Authors: Lawrence Reynolds
      Abstract: Author: Lawrence Reynolds
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.383-b
       
  • [This Week in Science] Chronic malaria shortens telomeres
    • Authors: Caroline Ash
      Abstract: Author: Caroline Ash
      Keywords: Chronic Infection
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-a
       
  • [This Week in Science] Getting a grip
    • Authors: Andrew M. Sugden
      Abstract: Author: Andrew M. Sugden
      Keywords: Human Evolution
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-b
       
  • [This Week in Science] For T cells, variety is the spice of life
    • Authors: Kristen L. Mueller
      Abstract: Author: Kristen L. Mueller
      Keywords: Cell Immunity
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.384-c
       
  • [Book Review] Hard-wired for good?
    • Authors: Frans B. M. de Waal
      Abstract: Recent scientific data suggests that human prosocial behavior is more than just a product of education, culture, and religion. Instead, it seems that the seeds of morality may have a long history in our brains. Frans B. M. de Waal welcomes an accessible introduction to the biology and neuroscience of prosociality in a review of The Altruistic Brain: How We Are Naturally Good. Author: Frans B. M. de Waal
      Keywords: Neuroscience
      PubDate: 2015-01-23
      DOI: 10.1126/science.1261392
       
  • [Book Review] Curriculum and the Cold War
    • Authors: Jeremy Kilpatrick
      Abstract: Spurred by concerns that the American education system was failing to keep pace with the Soviets after the "Sputnik crisis" of the late 1950s, a dramatic change occurred in the mathematics that was taught in American schools in the 1960s. This "new math", as it was known, was controversial from the start and ultimately short-lived. Jeremy Kilpatrick takes a second look at this contentious era in a review of The New Math: A Political History. Author: Jeremy Kilpatrick
      Keywords: Education
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa1471
       
  • [Perspective] Understanding artemisinin resistance
    • Authors: Carol Hopkins Sibley
      Abstract: The drug resistance specter looms over most infectious diseases. Malaria provides a particularly urgent example of increasing resistance and treatment failure. In the past decade, artemisinin combination therapies (ACTs) have contributed to impressive reductions in malaria morbidity and mortality (1). However, in 2009, Dondorp et al. found that when patients in western Cambodia infected with Plasmodium falciparum (the deadliest form of malaria) were treated with ACTs, they took longer than normal to clear their parasites. It is the artemisinin component that normally clears parasites quickly, and the authors therefore concluded that this component of the ACT was compromised (2). Slow-clearing parasites were also found in western Thailand and other parts of Cambodia (see the first figure) (3, 4). Two reports in this issue, by Mok et al. (page 431) (5) and Straimer et al. (page 428) (6), apply specialized techniques to better understand the mechanisms that underlie this resistance to artemisinins. Author: Carol Hopkins Sibley
      Keywords: Infectious Diseases
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa4102
       
  • [Policy Forum] Smoke and fire over e-cigarettes
    • Authors: Amy L. Fairchild
      Abstract: In advance of a critical Framework Convention on Tobacco Control (FCTC) held in October 2014, two groups of scientists and public health experts launched a global battle royal over electronic cigarettes—devices that heat liquid nicotine but involve no tobacco.
      Authors : Amy L. Fairchild, Ronald Bayer
      Keywords: Public Health
      PubDate: 2015-01-23
      DOI: 10.1126/science.1260761
       
  • [Policy Forum] Brazil's Soy Moratorium
    • Authors: H. K. Gibbs
      Abstract: Brazil'fs Soy Moratorium (SoyM) was the first voluntary zero-deforestation agreement implemented in the tropics and set the stage for supply-chain governance of other commodities, such as beef and palm oil [supplementary material (SM)]. In response to pressure from retailers and nongovernmental organizations (NGOs), major soybean traders signed the SoyM, agreeing not to purchase soy grown on lands deforested after July 2006 in the Brazilian Amazon. The soy industry recently extended the SoyM to May 2016, by which time they assert that Brazil'fs environmental governance, such as the increased enforcement and national implementation of the Rural Environmental Registry of private properties (Portuguese acronym CAR) mandated by the Forest Code (FC) (1), will be robust enough to justify ending the agreement (2). We argue that a longer-term commitment is needed to help maintain deforestation-free soy supply chains, as full compliance and enforcement of these regulations is likely years away. Ending the SoyM prematurely would risk a return to deforestation for soy expansion at a time when companies are committing to zero-deforestation supply chains (3).
      Authors : H. K. Gibbs, L. Rausch, J. Munger, I. Schelly, D. C. Morton, P. Noojipady, B. Soares-Filho, P. Barreto, L. Micol, N. F. Walker
      Keywords: Environment and Development
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa0181
       
  • [Perspective] Flexibility for specificity
    • Authors: Mark M. Davis
      Abstract: Different types of T lymphocytes play a key role in many immune responses, such as killing virally infected or cancerous cells directly, inducing high-affinity antibody responses in B cells, and increasing or decreasing responses from other immune cells. This multiplicity of roles may relate to their recognition properties, which are very difficult to evade. Moreover, cells are very diverse—for CD4+ T cells alone, there are at least six distinct subtypes. This raises the question of just how these different T cells are produced. Early evidence indicated that the type of T cell that dominates the response was dependent on the type of pathogen and route of entry (1, 2). However, over the past several years, more and more flexibility has been observed in a T cell's phenotype (3, 4). On page 400 of this issue, Becattini et al. (5) show that this flexibility is more the rule rather than the exception. Author: Mark M. Davis
      Keywords: Immunology
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa5082
       
  • [Feature] The insurgent
    • Authors: David Grimm
      Abstract: From a small wooden desk in a row home a few miles north of the U.S. Capitol, Justin Goodman is waging war against animal research as director of laboratory investigations at People for the Ethical Treatment of Animals. Whereas other activists stick to protests and publicity stunts, he and his team have spent the past 5 years challenging scientists on their own turf. In talks and papers published in the peer-reviewed literature, they marshal data in an attempt to show researchers that animal experimentation is flawed, cruel, and just plain worthless. Goodman's papers have questioned the validity of the university committees that oversee animal research, encouraged U.S. allies to explore alternatives to animals in military medical training, and wounded the reputation of the world's largest accreditor of lab animal welfare. But many scientists are unswayed, saying that the work is methodologically flawed and deeply misleading. They say that despite the veneer of science, Goodman's studies are anything but. Author: David Grimm
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.366
       
  • [Perspective] Play it again, SAM
    • Authors: Kevin Zahnle
      Abstract: Some discoveries are new, others old. Here, we consider one of each from NASA's Curiosity rover. The new discovery, reported by Mahaffy et al. (1) on page 412 of this issue, is a remarkable measurement of the deuterium-hydrogen (D/H) ratio in a Gale crater mudstone from 3 billion years ago. On page 415, Webster et al. (2) report on the latest chapter in the muddy matter of methane on Mars. What links them is that both were made using the tunable laser spectrometer (TLS), part of the SAM (Sample Analysis at Mars) package on the rover. Author: Kevin Zahnle
      Keywords: Planetary Science
      PubDate: 2015-01-23
      DOI: 10.1126/science.aaa3687
       
  • [In Depth] Malaria may accelerate aging in birds
    • Authors: Gretchen Vogel
      Abstract: Malaria is a scourge of humankind, but many birds seem to shrug it off. Although they are chronically infected with malaria parasites, their behavior seems unaffected, and they mostly reproduce and raise young just as well as noninfected birds. That was a puzzle not just for ornithologists but also for evolutionary biologists, who have long theorized that parasites inevitably take a toll on fitness. The birds' healthy appearance turns out to be deceiving, however. Drawing on data from a 3-decade study of great reed warblers in southern Sweden, researchers report this week in Science that long-term infection with malaria significantly shortened the birds' lives. The analysis also revealed a possible explanation: The blood cells of infected birds also had shorter telomeres, stretches of DNA that cap the ends of chromosomes and protect them during cell division. In many species, shorter telomeres are associated with aging and shorter life span. The shorter lives had a steep cost when it came to reproduction: lost breeding opportunities. On average, uninfected birds raised more than eight offspring to fledglings, infected birds just four. Author: Gretchen Vogel
      Keywords: Biology
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.362
       
  • [Feature] Probing the proton
    • Authors: Adrian Cho
      Abstract: Many decades after their discoveries, the basic building blocks of the atomic nucleus—the proton and the neutron—remain among the most mysterious of subatomic particles. In the cartoon view, the positively charged proton and the uncharged neutron both consist of trios of particles called up quarks and down quarks. In actuality, each is a pullulating mass of countless quarks, antiquarks, and gluons, massless particles that convey the strong nuclear force that holds quarks together. A nucleon is so messy that physicists can't say exactly how its most basic properties, such as its mass and spin, emerge from the tangle. But now physicists at Thomas Jefferson National Accelerator Facility here are finishing a $338 million upgrade to their particle accelerator, the Continuous Electron Beam Accelerator Facility, to double its energy and probe the innards of protons and neutrons with unprecedented precision. In the coming decade, a mosaic of measurements may finally give physicists a clearer view into the proton and the neutron. Author: Adrian Cho
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.363
       
  • [In Depth] Japan's nuclear renaissance dogged by waste challenge
    • Authors: Dennis Normile
      Abstract: Later this spring, Japan is likely to restart the first two of the 48 nuclear reactors idled in the aftermath of the 2011 meltdowns at the Fukushima Daiichi Nuclear Power Station. But the resumption of nuclear power generation is refocusing attention on a lingering challenge: what to do with the spent fuel. When Japan turned to nuclear power in the 1960s, it worried about uranium supplies and wanted to minimize the amount of nuclear waste. So it planned on spent fuel reprocessing, which reduces the volume of waste needing long-term storage and produces fresh fuel for reactors. A private firm owned by the country's nuclear utilities started building a reprocessing plant in the northern village of Rokkasho in 1993. But it took more than 2 decades to work the kinks out of an experimental vitrification process. The plant is finally due to come online in spring 2016. But the country is still searching for a site for a deep underground repository for the highly radioactive nuclear waste left over from reprocessing. For the time being, it will be encased in glass and stored until a permanent solution is found. Author: Dennis Normile
      Keywords: Nuclear Power
      PubDate: 2015-01-23
      DOI: 10.1126/science.347.6220.361
       
 
 
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