Base de dados : MEDLINE
Pesquisa : G01.060.075.680 [Categoria DeCS]
Referências encontradas : 534 [refinar]
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[PMID]:28522499
[Au] Autor:Burr D
[Ad] Endereço:Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996, USA. dburr1@utk.edu.
[Ti] Título:Defining the topography of a planetary body.
[So] Source:Science;356(6339):708, 2017 05 19.
[Is] ISSN:1095-9203
[Cp] País de publicação:United States
[La] Idioma:eng
[Mh] Termos MeSH primário: Meio Ambiente Extraterreno
Planetas
[Mh] Termos MeSH secundário: Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE; COMMENT
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171013
[Lr] Data última revisão:
171013
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170520
[St] Status:MEDLINE
[do] DOI:10.1126/science.aan2719


  2 / 534 MEDLINE  
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[PMID]:28426003
[Au] Autor:Dittmann JA; Irwin JM; Charbonneau D; Bonfils X; Astudillo-Defru N; Haywood RD; Berta-Thompson ZK; Newton ER; Rodriguez JE; Winters JG; Tan TG; Almenara JM; Bouchy F; Delfosse X; Forveille T; Lovis C; Murgas F; Pepe F; Santos NC; Udry S; Wünsche A; Esquerdo GA; Latham DW; Dressing CD
[Ad] Endereço:Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA.
[Ti] Título:A temperate rocky super-Earth transiting a nearby cool star.
[So] Source:Nature;544(7650):333-336, 2017 04 19.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy when the planets pass in front of these stars. Statistical results suggest that the nearest transiting Earth-sized planet in the liquid-water, habitable zone of an M dwarf star is probably around 10.5 parsecs away. A temperate planet has been discovered orbiting Proxima Centauri, the closest M dwarf, but it probably does not transit and its true mass is unknown. Seven Earth-sized planets transit the very low-mass star TRAPPIST-1, which is 12 parsecs away, but their masses and, particularly, their densities are poorly constrained. Here we report observations of LHS 1140b, a planet with a radius of 1.4 Earth radii transiting a small, cool star (LHS 1140) 12 parsecs away. We measure the mass of the planet to be 6.6 times that of Earth, consistent with a rocky bulk composition. LHS 1140b receives an insolation of 0.46 times that of Earth, placing it within the liquid-water, habitable zone. With 90 per cent confidence, we place an upper limit on the orbital eccentricity of 0.29. The circular orbit is unlikely to be the result of tides and therefore was probably present at formation. Given its large surface gravity and cool insolation, the planet may have retained its atmosphere despite the greater luminosity (compared to the present-day) of its host star in its youth. Because LHS 1140 is nearby, telescopes currently under construction might be able to search for specific atmospheric gases in the future.
[Mh] Termos MeSH primário: Meio Ambiente Extraterreno/química
Planetas
Astros Celestes
Temperatura Ambiente
[Mh] Termos MeSH secundário: Exobiologia
Água/análise
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170824
[Lr] Data última revisão:
170824
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170421
[St] Status:MEDLINE
[do] DOI:10.1038/nature22055


  3 / 534 MEDLINE  
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[PMID]:28418704
[Au] Autor:Reinhard CT; Olson SL; Schwieterman EW; Lyons TW
[Ad] Endereço:1 NASA Astrobiology Institute .
[Ti] Título:False Negatives for Remote Life Detection on Ocean-Bearing Planets: Lessons from the Early Earth.
[So] Source:Astrobiology;17(4):287-297, 2017 Apr.
[Is] ISSN:1557-8070
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Ocean-atmosphere chemistry on Earth has undergone dramatic evolutionary changes throughout its long history, with potentially significant ramifications for the emergence and long-term stability of atmospheric biosignatures. Though a great deal of work has centered on refining our understanding of false positives for remote life detection, much less attention has been paid to the possibility of false negatives, that is, cryptic biospheres that are widespread and active on a planet's surface but are ultimately undetectable or difficult to detect in the composition of a planet's atmosphere. Here, we summarize recent developments from geochemical proxy records and Earth system models that provide insight into the long-term evolution of the most readily detectable potential biosignature gases on Earth-oxygen (O ), ozone (O ), and methane (CH ). We suggest that the canonical O -CH disequilibrium biosignature would perhaps have been challenging to detect remotely during Earth's ∼4.5-billion-year history and that in general atmospheric O /O levels have been a poor proxy for the presence of Earth's biosphere for all but the last ∼500 million years. We further suggest that detecting atmospheric CH would have been problematic for most of the last ∼2.5 billion years of Earth's history. More broadly, we stress that internal oceanic recycling of biosignature gases will often render surface biospheres on ocean-bearing silicate worlds cryptic, with the implication that the planets most conducive to the development and maintenance of a pervasive biosphere will often be challenging to characterize via conventional atmospheric biosignatures. Key Words: Biosignatures-Oxygen-Methane-Ozone-Exoplanets-Planetary habitability. Astrobiology 17, 287-297.
[Mh] Termos MeSH primário: Terra (Planeta)
Exobiologia
Meio Ambiente Extraterreno
Oceanos e Mares
Planetas
[Mh] Termos MeSH secundário: Atmosfera/química
Metano/análise
Oxigênio/análise
Ozônio/análise
Análise Espectral
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
66H7ZZK23N (Ozone); OP0UW79H66 (Methane); S88TT14065 (Oxygen)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170508
[Lr] Data última revisão:
170508
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170419
[St] Status:MEDLINE
[do] DOI:10.1089/ast.2016.1598


  4 / 534 MEDLINE  
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[PMID]:28358088
[Au] Autor:Morais H; Namouni F
[Ad] Endereço:Department of Statistics, Applied Mathematics and Computer Science, Institute of Geosciences and Exact Sciences, São Paulo State University (UNESP), 13506-900 Rio Claro, Brazil.
[Ti] Título:Planetary science: Reckless orbiting in the Solar System.
[So] Source:Nature;543(7647):635-636, 2017 03 29.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Mh] Termos MeSH primário: Planetas
Sistema Solar
[Pt] Tipo de publicação:NEWS; COMMENT
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170620
[Lr] Data última revisão:
170620
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170331
[St] Status:MEDLINE
[do] DOI:10.1038/543635a


  5 / 534 MEDLINE  
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[PMID]:28282216
[Au] Autor:Poch O; Frey J; Roditi I; Pommerol A; Jost B; Thomas N
[Ad] Endereço:1 Center for Space and Habitability , Universität Bern, Bern, Switzerland .
[Ti] Título:Remote Sensing of Potential Biosignatures from Rocky, Liquid, or Icy (Exo)Planetary Surfaces.
[So] Source:Astrobiology;17(3):231-252, 2017 Mar.
[Is] ISSN:1557-8070
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:To detect signs of life by remote sensing on objects of our Solar System and on exoplanets, the characterization of light scattered by surface life material could complement possible clues given by the atmospheric composition. We reviewed the reflectance spectra of a broad selection of major biomolecules that constitute terrestrial carbon-based life from 0.4 to 2.4 µm, and we discuss their detectability through atmospheric spectral windows. Biomolecule features in the near-infrared (0.8-2.4 µm) will likely be obscured by water spectral features and some atmospheric gases. The visible range (0.4-0.8 µm), including the strong spectral features of pigments, is the most favorable. We investigated the detectability of a pigmented microorganism (Deinococcus radiodurans) when mixed with silica sand, liquid water, and water-ice particles representative of diverse surfaces of potentially habitable worlds. We measured the visible to near-infrared reflectance spectra (0.4-2.4 µm) and the visible phase curves (at 0.45 and 0.75 µm) of the mixtures to assess how the surface medium and the viewing geometry affect the detectability of the microorganisms. The results show that ice appears to be the most favorable medium for the detection of pigments. Water ice is bright and featureless from 0.4 to 0.8 µm, allowing the absorption of any pigment present in the ice to be well noticeable. We found that the visible phase curve of water ice is the most strongly affected by the presence of pigments, with variations of the spectral slope by more than a factor of 3 with phase angles. Finally, we show that the sublimation of the ice results in the concentration of the biological material onto the surface and the consequent increase of its signal. These results have applications to the search for life on icy worlds, such as Europa or Enceladus. Key Words: Remote sensing-Biosignatures-Reflectance spectroscopy-Exoplanets-Spectroscopic biosignatures-Pigments. Astrobiology 17, 231-252.
[Mh] Termos MeSH primário: Bactérias/metabolismo
Exobiologia/métodos
Meio Ambiente Extraterreno
Planetas
Tecnologia de Sensoriamento Remoto/métodos
[Mh] Termos MeSH secundário: Atmosfera/química
Deinococcus/metabolismo
Gelo
Origem da Vida
Dióxido de Silício/química
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ice); 059QF0KO0R (Water); 7631-86-9 (Silicon Dioxide)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171009
[Lr] Data última revisão:
171009
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170311
[St] Status:MEDLINE
[do] DOI:10.1089/ast.2016.1523


  6 / 534 MEDLINE  
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[PMID]:28230125
[Au] Autor:Gillon M; Triaud AH; Demory BO; Jehin E; Agol E; Deck KM; Lederer SM; de Wit J; Burdanov A; Ingalls JG; Bolmont E; Leconte J; Raymond SN; Selsis F; Turbet M; Barkaoui K; Burgasser A; Burleigh MR; Carey SJ; Chaushev A; Copperwheat CM; Delrez L; Fernandes CS; Holdsworth DL; Kotze EJ; Van Grootel V; Almleaky Y; Benkhaldoun Z; Magain P; Queloz D
[Ad] Endereço:Space Sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, Allée du 6 Août 19C, Bat. B5C, 4000 Liège, Belgium.
[Ti] Título:Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1.
[So] Source:Nature;542(7642):456-460, 2017 02 22.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:One aim of modern astronomy is to detect temperate, Earth-like exoplanets that are well suited for atmospheric characterization. Recently, three Earth-sized planets were detected that transit (that is, pass in front of) a star with a mass just eight per cent that of the Sun, located 12 parsecs away. The transiting configuration of these planets, combined with the Jupiter-like size of their host star-named TRAPPIST-1-makes possible in-depth studies of their atmospheric properties with present-day and future astronomical facilities. Here we report the results of a photometric monitoring campaign of that star from the ground and space. Our observations reveal that at least seven planets with sizes and masses similar to those of Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain, such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.1 and 12.35 days) are near-ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inwards. Moreover, the seven planets have equilibrium temperatures low enough to make possible the presence of liquid water on their surfaces.
[Mh] Termos MeSH primário: Planetas
Astros Celestes
[Mh] Termos MeSH secundário: Exobiologia
Meio Ambiente Extraterreno/química
Temperatura Ambiente
Água/análise
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170224
[St] Status:MEDLINE
[do] DOI:10.1038/nature21360


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[PMID]:28125066
[Au] Autor:Iriti M; Varoni EM
[Ad] Endereço:Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Milano, via G. Celoria 2, 20133 Milan, Italy. marcello.iriti@unimi.it.
[Ti] Título:Pulses, Healthy, and Sustainable Food Sources for Feeding the Planet.
[So] Source:Int J Mol Sci;18(2), 2017 Jan 25.
[Is] ISSN:1422-0067
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:n/a.
[Mh] Termos MeSH primário: Fabaceae
Comportamento Alimentar
Alimentos
Nível de Saúde
Planetas
[Mh] Termos MeSH secundário: Conservação dos Recursos Naturais
Seres Humanos
[Pt] Tipo de publicação:EDITORIAL
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170428
[Lr] Data última revisão:
170428
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170127
[St] Status:MEDLINE


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[PMID]:28052100
[Au] Autor:Xie X; Zubarev RA
[Ad] Endereço:Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
[Ti] Título:On the Effect of Planetary Stable Isotope Compositions on Growth and Survival of Terrestrial Organisms.
[So] Source:PLoS One;12(1):e0169296, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Isotopic compositions of reactants affect the rates of chemical and biochemical reactions. Usually it is assumed that heavy stable isotope enrichment leads to progressively slower reactions. Yet the effect of stable isotopes may be nonlinear, as exemplified by the "isotopic resonance" phenomenon. Since the isotopic compositions of other planets of Solar system, including Mars and Venus, are markedly different from terrestrial (e.g., deuterium content is ≈5 and ≈100 times higher, respectively), it is far from certain that terrestrial life will thrive in these isotopic conditions. Here we found that Martian deuterium content negatively affected survival of shrimp in semi-closed biosphere on a year-long time scale. Moreover, the bacterium Escherichia coli grows slower at Martian isotopic compositions and even slower at Venus's compositions. Thus, the biological impact of varying stable isotope compositions needs to be taken into account when planning interplanetary missions.
[Mh] Termos MeSH primário: Decápodes (Crustáceos)/crescimento & desenvolvimento
Escherichia coli/crescimento & desenvolvimento
Marcação por Isótopo
Planetas
[Mh] Termos MeSH secundário: Animais
Ecossistema
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170809
[Lr] Data última revisão:
170809
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170105
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0169296


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[PMID]:28054628
[Au] Autor:Gibney E
[Ti] Título:2017 sneak peek: What the new year holds for science.
[So] Source:Nature;541(7635):14-15, 2016 12 22.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Mh] Termos MeSH primário: Ciência/tendências
[Mh] Termos MeSH secundário: Animais
Regiões Antárticas
Antozoários
Astronomia/tendências
Sistemas CRISPR-Cas
China
Mudança Climática
Computadores/tendências
Ecologia/tendências
França
Edição de Genes/legislação & jurisprudência
Alemanha
Células-Tronco Embrionárias Humanas
Seres Humanos
Imunoterapia/tendências
Leucemia/imunologia
Leucemia/terapia
Linfoma/imunologia
Linfoma/terapia
Microbiota
Oceanos e Mares
Planetas
Política
Teoria Quântica
Energia Solar
Pesquisa com Células-Tronco
Reino Unido
Estados Unidos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1702
[Cu] Atualização por classe:170206
[Lr] Data última revisão:
170206
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170106
[St] Status:MEDLINE
[do] DOI:10.1038/541014a


  10 / 534 MEDLINE  
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[PMID]:28001448
[Au] Autor:Ziurys LM; Halfen DT; Geppert W; Aikawa Y
[Ad] Endereço:1 Department of Chemistry and Biochemistry, Department of Astronomy, and Arizona Radio Observatory, University of Arizona , Tucson, Arizona, USA .
[Ti] Título:Following the Interstellar History of Carbon: From the Interiors of Stars to the Surfaces of Planets.
[So] Source:Astrobiology;16(12):997-1012, 2016 Dec.
[Is] ISSN:1557-8070
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The chemical history of carbon is traced from its origin in stellar nucleosynthesis to its delivery to planet surfaces. The molecular carriers of this element are examined at each stage in the cycling of interstellar organic material and their eventual incorporation into solar system bodies. The connection between the various interstellar carbon reservoirs is also examined. Carbon has two stellar sources: supernova explosions and mass loss from evolved stars. In the latter case, the carbon is dredged up from the interior and then ejected into a circumstellar envelope, where a rich and unusual C-based chemistry occurs. This molecular material is eventually released into the general interstellar medium through planetary nebulae. It is first incorporated into diffuse clouds, where carbon is found in polyatomic molecules such as H CO, HCN, HNC, c-C H , and even C . These objects then collapse into dense clouds, the sites of star and planet formation. Such clouds foster an active organic chemistry, producing compounds with a wide range of functional groups with both gas-phase and surface mechanisms. As stars and planets form, the chemical composition is altered by increasing stellar radiation, as well as possibly by reactions in the presolar nebula. Some molecular, carbon-rich material remains pristine, however, encapsulated in comets, meteorites, and interplanetary dust particles, and is delivered to planet surfaces. Key Words: Carbon isotopes-Prebiotic evolution-Interstellar molecules-Comets-Meteorites. Astrobiology 16, 997-1012.
[Mh] Termos MeSH primário: Carbono/análise
Planetas
Astros Celestes/química
[Mh] Termos MeSH secundário: Poeira Cósmica/análise
Meteoroides
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Cosmic Dust); 7440-44-0 (Carbon)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170929
[Lr] Data última revisão:
170929
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161222
[St] Status:MEDLINE
[do] DOI:10.1089/ast.2016.1484



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