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A remnant planetary core in the hot-Neptune desert 期刊论文
NATURE, 2020, 583 (7814) : 39-+
作者:  David J. Armstrong;  Thé;  o A. Lopez;  Vardan Adibekyan;  Richard A. Booth;  Edward M. Bryant;  Karen A. Collins;  Magali Deleuil;  Alexandre Emsenhuber;  Chelsea X. Huang;  George W. King;  Jorge Lillo-Box;  Jack J. Lissauer;  Elisabeth Matthews;  Olivier Mousis;  Louise D. Nielsen;  Hugh Osborn;  Jon Otegi;  Nuno C. Santos;  ;  rgio G. Sousa;  Keivan G. Stassun;  Dimitri Veras;  Carl Ziegler;  Jack S. Acton;  Jose M. Almenara;  David R. Anderson;  David Barrado;  Susana C. C. Barros;  Daniel Bayliss;  Claudia Belardi;  Francois Bouchy;  ;  sar Briceñ;  o;  Matteo Brogi;  David J. A. Brown;  Matthew R. Burleigh;  Sarah L. Casewell;  Alexander Chaushev;  David R. Ciardi;  Kevin I. Collins;  Knicole D. Coló;  n;  Benjamin F. Cooke;  Ian J. M. Crossfield;  Rodrigo F. Dí;  az;  Elisa Delgado Mena;  Olivier D. S. Demangeon;  Caroline Dorn;  Xavier Dumusque;  Philipp Eigmü;  ller;  Michael Fausnaugh;  Pedro Figueira;  Tianjun Gan;  Siddharth Gandhi;  Samuel Gill;  Erica J. Gonzales;  Michael R. Goad;  Maximilian N. Gü;  nther;  Ravit Helled;  Saeed Hojjatpanah;  Steve B. Howell;  James Jackman;  James S. Jenkins;  Jon M. Jenkins;  Eric L. N. Jensen;  Grant M. Kennedy;  David W. Latham;  Nicholas Law;  Monika Lendl;  Michael Lozovsky;  Andrew W. Mann;  Maximiliano Moyano;  James McCormac;  Farzana Meru;  Christoph Mordasini;  Ares Osborn;  Don Pollacco;  Didier Queloz;  Liam Raynard;  George R. Ricker;  Pamela Rowden;  Alexandre Santerne;  Joshua E. Schlieder;  Sara Seager;  Lizhou Sha;  Thiam-Guan Tan;  Rosanna H. Tilbrook;  Eric Ting;  Sté;  phane Udry;  Roland Vanderspek;  Christopher A. Watson;  Richard G. West;  Paul A. Wilson;  Joshua N. Winn;  Peter Wheatley;  Jesus Noel Villasenor;  Jose I. Vines;  Zhuchang Zhan
收藏  |  浏览/下载:20/0  |  提交时间:2020/07/06

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune '  desert'  (1,2)(a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b(3), which is thought to have an unusually massive core, and recent discoveries such as LTT9779b(4)and NGTS-4b(5), on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune'  s but an anomalously large mass of39.1-2.6+2.7Earth masses and a density of5.2-0.8+0.7grams per cubic centimetre, similar to Earth'  s. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than3.9-0.9+0.8 per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation(6). Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.


Observations of TOI-849b reveal a radius smaller than Neptune'  s but a large mass of about 40 Earth masses, indicating that the planet is the remnant core of a gas giant.


  
International evaluation of an AI system for breast cancer screening 期刊论文
NATURE, 2020, 577 (7788) : 89-+
作者:  McKinney, Scott Mayer;  Sieniek, Marcin;  Godbole, Varun;  Godwin, Jonathan;  Antropova, Natasha;  Ashrafian, Hutan;  Back, Trevor;  Chesus, Mary;  Corrado, Greg C.;  Darzi, Ara;  Etemadi, Mozziyar;  Garcia-Vicente, Florencia;  Gilbert, Fiona J.;  Halling-Brown, Mark;  Hassabis, Demis;  Jansen, Sunny;  Karthikesalingam, Alan;  Kelly, Christopher J.;  King, Dominic;  Ledsam, Joseph R.;  Melnick, David;  Mostofi, Hormuz;  Peng, Lily;  Reicher, Joshua Jay;  Romera-Paredes, Bernardino;  Sidebottom, Richard;  Suleyman, Mustafa;  Tse, Daniel;  Young, Kenneth C.;  De Fauw, Jeffrey;  Shetty, Shravya
收藏  |  浏览/下载:15/0  |  提交时间:2020/07/03

Screening mammography aims to identify breast cancer at earlier stages of the disease, when treatment can be more successful(1). Despite the existence of screening programmes worldwide, the interpretation of mammograms is affected by high rates of false positives and false negatives(2). Here we present an artificial intelligence (AI) system that is capable of surpassing human experts in breast cancer prediction. To assess its performance in the clinical setting, we curated a large representative dataset from the UK and a large enriched dataset from the USA. We show an absolute reduction of 5.7% and 1.2% (USA and UK) in false positives and 9.4% and 2.7% in false negatives. We provide evidence of the ability of the system to generalize from the UK to the USA. In an independent study of six radiologists, the AI system outperformed all of the human readers: the area under the receiver operating characteristic curve (AUC-ROC) for the AI system was greater than the AUC-ROC for the average radiologist by an absolute margin of 11.5%. We ran a simulation in which the AI system participated in the double-reading process that is used in the UK, and found that the AI system maintained non-inferior performance and reduced the workload of the second reader by 88%. This robust assessment of the AI system paves the way for clinical trials to improve the accuracy and efficiency of breast cancer screening.


  
Increased drought severity tracks warming in the United States' largest river basin 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (21) : 11328-11336
作者:  Martin, Justin T.;  Pederson, Gregory T.;  Woodhouse, Connie A.;  Cook, Edward R.;  McCabe, Gregory J.;  Anchukaitis, Kevin J.;  Wise, Erika K.;  Erger, Patrick J.;  Dolan, Larry;  McGuire, Marketa;  Gangopadhyay, Subhrendu;  Chase, Katherine J.;  Littell, Jeremy S.;  Gray, Stephen T.;  George, Scott St.;  Friedman, Jonathan M.;  Sauchyn, David J.;  St-Jacques, Jeannine-Marie;  King, John
收藏  |  浏览/下载:14/0  |  提交时间:2020/05/13
drought severity  streamflow  temperature  precipitation  water resources  
Spectroscopic confirmation of a mature galaxy cluster at a redshift of 2 期刊论文
NATURE, 2020, 577 (7788) : 39-+
作者:  Willis, J. P.;  Canning, R. E. A.;  Noordeh, E. S.;  Allen, S. W.;  King, A. L.;  Mantz, A.;  Morris, R. G.;  Stanford, S. A.;  Brammer, G.
收藏  |  浏览/下载:12/0  |  提交时间:2020/07/03

Galaxy clusters are the most massive virialized structures in the Universe and are formed through the gravitational accretion of matter over cosmic time(1). The discovery(2) of an evolved galaxy cluster at redshift z = 2, corresponding to a look-back time of 10.4 billion years, provides an opportunity to study its properties. The galaxy cluster XLSSC 122 was originally detected as a faint, extended X-ray source in the XMM Large Scale Structure survey and was revealed to be coincident with a compact over-density of galaxies(2) with photometric redshifts of 1.9 +/- 0.2. Subsequent observations3 at millimetre wavelengths detected a Sunyaev-Zel'  dovich decrement along the line of sight to XLSSC 122, thus confirming the existence of hot intracluster gas, while deep imaging spectroscopy from the European Space Agency'  s X-ray Multi-Mirror Mission (XMM-Newton) revealed(4) an extended, X-ray-bright gaseous atmosphere with a virial temperature of 60 million Kelvin, enriched with metals to the same extent as are local clusters. Here we report optical spectroscopic observations of XLSSC 122 and identify 37 member galaxies at a mean redshift of 1.98, corresponding to a look-back time of 10.4 billion years. We use photometry to determine a mean, dust-free stellar age of 2.98 billion years, indicating that star formation commenced in these galaxies at a mean redshift of 12, when the Universe was only 370 million years old. The full range of inferred formation redshifts, including the effects of dust, covers the interval from 7 to 13. These observations confirm that XLSSC 122 is a remarkably mature galaxy cluster with both evolved stellar populations in the member galaxies and a hot, metal-rich gas composing the intracluster medium.


  
Resolving the Differences in the Simulated and Reconstructed Temperature Response to Volcanism 期刊论文
GEOPHYSICAL RESEARCH LETTERS, 2020, 47 (8)
作者:  Zhu, Feng;  Emile-Geay, Julien;  Hakim, Gregory J.;  King, Jonathan;  Anchukaitis, Kevin J.
收藏  |  浏览/下载:13/0  |  提交时间:2020/07/02
volcanic eruptions  temperature response  simulation-reconstruction comparison  Last Millennium Reanalysis  paleoclimate data assimilation  Superposed Epoch Analysis  
A La Nina-Like Climate Response to South African Biomass Burning Aerosol in CESM Simulations 期刊论文
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 2020, 125 (6)
作者:  Amiri-Farahani, Anahita;  Allen, Robert J.;  Li, King-Fai;  Nabat, Pierre;  Westervelt, Daniel M.
收藏  |  浏览/下载:9/0  |  提交时间:2020/07/02
The Role of Individual Heterogeneity in Collective Animal Behaviour 期刊论文
TRENDS IN ECOLOGY & EVOLUTION, 2020, 35 (3) : 278-291
作者:  Jolles, Jolle W.;  King, Andrew J.;  Killen, Shaun S.
收藏  |  浏览/下载:1/0  |  提交时间:2020/07/02
The role of climate variability in Australian drought 期刊论文
NATURE CLIMATE CHANGE, 2020, 10 (3) : 177-179
作者:  King, Andrew D.;  Pitman, Andy J.;  Henley, Benjamin J.;  Ukkola, Anna M.;  Brown, Josephine R.
收藏  |  浏览/下载:6/0  |  提交时间:2020/05/13
The seismicity of Mars 期刊论文
NATURE GEOSCIENCE, 2020, 13 (3) : 205-+
作者:  Giardini, D.;  Lognonne, P.;  Banerdt, W. B.;  Pike, W. T.;  Christensen, U.;  Ceylan, S.;  Clinton, J. F.;  van Driel, M.;  Staehler, S. C.;  Boese, M.;  Garcia, R. F.;  Khan, A.;  Panning, M.;  Perrin, C.;  Banfield, D.;  Beucler, E.;  Charalambous, C.;  Euchner, F.;  Horleston, A.;  Jacob, A.;  Kawamura, T.;  Kedar, S.;  Mainsant, G.;  Scholz, J. -R.;  Smrekar, S. E.;  Spiga, A.;  Agard, C.;  Antonangeli, D.;  Barkaoui, S.;  Barrett, E.;  Combes, P.;  Conejero, V.;  Daubar, I.;  Drilleau, M.;  Ferrier, C.;  Gabsi, T.;  Gudkova, T.;  Hurst, K.;  Karakostas, F.;  King, S.;  Knapmeyer, M.;  Knapmeyer-Endrun, B.;  Llorca-Cejudo, R.;  Lucas, A.;  Luno, L.;  Margerin, L.;  McClean, J. B.;  Mimoun, D.;  Murdoch, N.;  Nimmo, F.;  Nonon, M.;  Pardo, C.;  Rivoldini, A.;  Manfredi, J. A. Rodriguez;  Samuel, H.;  Schimmel, M.;  Stott, A. E.;  Stutzmann, E.;  Teanby, N.;  Warren, T.;  Weber, R. C.;  Wieczorek, M.;  Yana, C.
收藏  |  浏览/下载:11/0  |  提交时间:2020/05/13
Impacts of current and future large dams on the geographic range connectivity of freshwater fish worldwide 期刊论文
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2020, 117 (7) : 3648-3655
作者:  Barbarossa, Valerio;  Schmitt, Rafael J. P.;  Huijbregts, Mark A. J.;  Zarfl, Christiane;  King, Henry;  Schipper, Aafke M.
收藏  |  浏览/下载:15/0  |  提交时间:2020/05/13
habitat fragmentation  hydropower  river management  migratory fish  biodiversity