National Centre of Competence in Research PlanetS
Gesellschaftsstrasse 6 | CH-3012 Bern | Switzerland
  Tel. +41 (0)31 631 32 39

Project 2.5: Formation and composition of core-dominated planets

Project 2.5 is led by Yann Alibert, and  structured around two different axes. The first axis consists in the study of  planet formation in different environments , with a focus on gas-poor planets and their volatile content. These planets are indeed the only ones that can potentially be habitable, so the study of their formation and composition is of fundamental importance. The second axis is to develop new advanced statistical techniques, inspired by machine learning and big data science . These new methods are necessary in order to process the vast amount of data coming from both simulations and present-day and future observations.

Planet formation in different environments

We develop planetary system formation models, based on either planetesimal or pebble accretion, and for solar and low-mass stars. See more on our dedicated page.

Planetary system formation around a low mass star

Formation of a planetary system around a Trappist-1 like star. The horizontal axis shows the semi-major axis of the planets (initially 50 planetary embryos), the vertical axis showing their mass. The size of the center of the symbols representing planets is proportional to their core radius, and the size of the layer above the center is proportional to the thickness of the planets’ atmosphere. Finally, the color code represents the amount of ices in the planet. At some point on the video, the mean motion resonances appear on the plot, and, towards the end, the location of the Trappist-1 system in the diagram appear.

Machine learning in planetary sciences

Planetary system formation model generate a very large amount of data that must be analysed using machine learning and advanced statistical tools.

TSNE based on the similarity between planetary systems

Exemple of dimensionality reduction (a type of unsupervised machine learning technique). In the video, the location of points (each of them representing a planetary system) is computed in order to reflect the similarity between planetary systems (closer points represent similar planetary systems).

Authors:
Jutzi, Martin; Michel, Patrick; Richardson, Derek C.
Publication:
Icarus, Volume 317, p. 215-228.
Copyright ©
(c) 2019 Elsevier Science B.V. All rights reserved.

2018 December

Authors:
Wada, Koji; Grott, Matthias; Michel, Patrick; Walsh, Kevin J.; Barucci, Antonella M.; Biele, Jens; Blum, Jürgen; Ernst, Carolyn M.; Grundmann, Jan Thimo; Gundlach, Bastian; Hagermann, Axel; Hamm, Maximilian; Jutzi, Martin; Kim, Myung-Jin; Kührt, Ekkehard; Le Corre, Lucille; Libourel, Guy; Lichtenheldt, Roy; Maturilli, Alessandro; Messenger, Scott R.; Michikami, Tatsuhiro; Miyamoto, Hideaki; Mottola, Stefano; Müller, Thomas; Nakamura, Akiko M.; Nittler, Larry R.; Ogawa, Kazunori; Okada, Tatsuaki; Palomba, Ernesto; Sakatani, Naoya; Schröder, Stefan E.; Senshu, Hiroki; Takir, Driss; Zolensky, Michael E.
Publication:
Progress in Earth and Planetary Science, Volume 5, Issue 1, article id. 82, 30 pp.
Copyright ©
(c) 2018

2018 November

Authors:
Brügger, N.; Alibert, Y.; Ataiee, S.; Benz, W.
Publication:
Astronomy & Astrophysics, Volume 619, id.A174, 13 pp.

2018 October

Authors:
Dorn, Caroline; Mosegaard, Klaus; Grimm, Simon L.; Alibert, Yann
Publication:
The Astrophysical Journal, Volume 865, Issue 1, article id. 20, 17 pp. (2018).

2018 August

Authors:
Dipierro, Giovanni; Laibe, Guillaume; Alexander, Richard; Hutchison, Mark
Publication:
Monthly Notices of the Royal Astronomical Society, Volume 479, Issue 3, p.4187-4206
Copyright ©
2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

2018 August

Authors:
Price, Daniel J.; Wurster, James; Tricco, Terrence S.; Nixon, Chris; Toupin, Stéven; Pettitt, Alex; Chan, Conrad; Mentiplay, Daniel; Laibe, Guillaume; Glover, Simon; Dobbs, Clare; Nealon, Rebecca; Liptai, David; Worpel, Hauke; Bonnerot, Clément; Dipierro, Giovanni; Ballabio, Giulia; Ragusa, Enrico; Federrath, Christoph; Iaconi, Roberto; Reichardt, Thomas; Forgan, Duncan; Hutchison, Mark; Constantino, Thomas; Ayliffe, Ben; Hirsh, Kieran; Lodato, Giuseppe
Publication:
Publications of the Astronomical Society of Australia, Volume 35, id.e031 82 pp.
Copyright ©
2018: Astronomical Society of Australia

2018 August

Authors:
Bolmont, Emeline; Coleman, Gavin; Blanco-Cuaresma, Sergi
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-1070

2018 August

Authors:
Ribas, I.; Tuomi, M.; Reiners, A.; Butler, R. P.; Morales, J. C.; Perger, M.; Dreizler, S.; Rodríguez-López, C.; González Hernández, J. I.; Rosich, A.; Feng, F.; Trifonov, T.; Vogt, S. S.; Caballero, J. A.; Hatzes, A.; Herrero, E.; Jeffers, S. V.; Lafarga, M.; Murgas, F.; Nelson, R. P.; Rodríguez, E.; Strachan, J. B. P.; Tal-Or, L.; Teske, J.; Toledo-Padrón, B.; Zechmeister, M.; Quirrenbach, A.; Amado, P. J.; Azzaro, M.; Béjar, V. J. S.; Barnes, J. R.; Berdiñas, Z. M.; Burt, J.; Coleman, G.; Cortés-Contreras, M.; Crane, J.; Engle, S. G.; Guinan, E. F.; Haswell, C. A.; Henning, Th.; Holden, B.; Jenkins, J.; Jones, H. R. A.; Kaminski, A.; Kiraga, M.; Kürster, M.; Lee, M. H.; López-González, M. J.; Montes, D.; Morin, J.; Ofir, A.; Pallé, E.; Rebolo, R.; Reffert, S.; Schweitzer, A.; Seifert, W.; Shectman, S. A.; Staab, D.; Street, R. A.; Suárez Mascareño, A.; Tsapras, Y.; Wang, S. X.; Anglada-Escudé, G.
Publication:
Nature, Volume 563, Issue 7731, p.365-368

2018 October

Authors:
Mathis, Stéphane; Bolmont, Emeline; Gallet, Florian; Damiani, Cilia; Charbonnel, Corinne; Amard, Louis; Alibert, Yann
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-439

2018 August

Authors:
Michel, Patrick; Küppers, Michael; Biele, Jens; Campo Bagatin, Adriano; Carry, Benoît; Charnoz, Sébastien; Fitzsimmons, Alan; Green, Simon; Hérique, Alain; Jutzi, Martin; Karatekin, Ozgur; de Leon, Julia; Murdoch, Naomi; Pravec, Petr; Sierks, Holger; Tortora, Paolo; Tsiganis, Kleomenis; Vincent, Jean-Baptiste; Wünnemmann, Kai; Carnelli, Ian
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-620

2018 August

Authors:
Turrini, D.; Svetsov, V.; Consolmagno, G.; Sirono, S.; Jutzi, M.
Publication:
Icarus, Volume 311, p. 224-241.
Copyright ©
(c) 2018 Elsevier Inc.

2018 August

Authors:
Brügger, Natacha; Alibert, Yann; Ataiee, Sareh; Benz, Willy
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-59

2018 August

Authors:
Ataiee, S.; Baruteau, C.; Alibert, Y.; Benz, W.
Publication:
Astronomy & Astrophysics, Volume 615, id.A110, 11 pp.

2018 June

Authors:
Michel, Patrick; Marchi, S.; Jutzi, M.; Schwartz, Stephen; Zhang, Yun; Richardson, Derek C.
Publication:
42nd COSPAR Scientific Assembly. Held 14-22 July 2018, in Pasadena, California, USA, Abstract id. B1.1-2-18.

2018 June

Authors:
Morbidelli, Alessandro; Karato, Shun-Ichiro; Ikoma, Masahiro; Alibert, Yann; Blanc, Michel; Elkins-Tanton, Lindy; Estrada, Paul; Hamano, Keiko; Lammer, Helmut; Raymond, Sean; Schönbächler, Maria
Publication:
Space Science Reviews, Volume 214, Issue 7, article id. 110, 8 pp.
Copyright ©
(c) 2018: Springer Nature B.V.

2018 September

Authors:
Alibert, Yann; Venturini, Julia; Helled, Ravit; Ataiee, Sareh; Burn, Remo; Senecal, Luc; Benz, Willy; Mayer, Lucio; Mordasini, Christoph; Quanz, Sascha P.; Schönbächler, Maria
Publication:
Nature Astronomy, Volume 2, p. 873-877

2018 July

Authors:
Suzuki, Daisuke; Bennett, David P.; Ida, Shigeru; Mordasini, Christoph; Bhattacharya, Aparna; Bond, Ian A.; Donachie, Martin; Fukui, Akihiko; Hirao, Yuki; Koshimoto, Naoki; Miyazaki, Shota; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Sumi, Takahiro; Alibert, Yann; Lin, Douglas N. C.
Publication:
The Astrophysical Journal Letters, Volume 869, Issue 2, article id. L34, 6 pp. (2018).

2018 November

Authors:
Ballabio, G.; Dipierro, G.; Veronesi, B.; Lodato, G.; Hutchison, M.; Laibe, G.; Price, D. J.
Publication:
Monthly Notices of the Royal Astronomical Society, Volume 477, Issue 2, p.2766-2771
Copyright ©
2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

2018 May

Authors:
Burn, Remo; Alibert, Yann; Mordasini, Christoph; Leleu, Adrien; Schlecker, Martin
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-376

2018 August

Authors:
Lichtenberg, Tim; Golabek, Gregor J.; Burn, Remo; Meyer, Michael R.; Alibert, Yann; Gerya, Taras V.; Mordasini, Christoph A.
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-132

2018 August

Authors:
Surville, Clément; Mayer, Lucio; Alibert, Yann
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-1145

2018 August

Authors:
Leleu, Adrien; Coleman, Gavin; Ataiee, Sareh
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-426

2018 August

Authors:
Leleu, Adrien; Jutzi, Martin; Rubin, Martin
Publication:
European Planetary Science Congress 2018, held 16-21 September 2018 at TU Berlin, Berlin, Germany, id.EPSC2018-247

2018 August

Authors:
Magrin, Demetrio; Viotto, Valentina; Beck, Thomas; Bruno, Giordano; Baroni, Marco; Turella, Andrea; Marinai, Massimo; Bergomi, Maria; Biondi, Federico; Munari, Matteo; Marafatto, Luca; Farinato, Jacopo; Greggio, Davide; Dima, Marco; Scandariato, Gaetano; Pagano, Isabella; Ragazzoni, Roberto; Rieder, Martin; Busch, Martin Diego; Piazza, Daniele; Bandy, Timothy; Broeg, Christopher; Fortier, Andrea; Hernandez, Eduardo; Cessa, Virginie; Benz, Willy; Piotto, Giampaolo; Giannuzzo, Ester; Dami, Michele; Battistelli, Enrico; Salatti, Mario; Tommasi, Elisabetta; De Angelis, Luigi; Deep, Atul; Ngan, Ivan; Ratti, Francesco; Gambicorti, Lisa; Rando, Nicola
Publication:
Proceedings of the SPIE, Volume 10698, id. 106983B 8 pp. (2018).
Copyright ©
(c) 2018: SPIE. Downloading of the abstract is permitted for personal use only.

2018 June

Authors:
Broeg, Christopher; Benz, Willy; Fortier, Andrea
Publication:
42nd COSPAR Scientific Assembly. Held 14-22 July 2018, in Pasadena, California, USA, Abstract id. E4.1-5-18.

2018 June

Authors:
Leleu, A.; Jutzi, M.; Rubin, M.
Publication:
Nature Astronomy, Volume 2, p. 555-561

2018 June

Authors:
Shibaike, Yuhito; Ormel, Chris W.; Ida, Shigeru; Okuzumi, Satoshi; Sasaki, Takanori
Publication:
The Astrophysical Journal, Volume 885, Issue 1, article id. 79, 19 pp. (2019).

2019 October

Authors:
Jutzi, Martin
Publication:
Planetary and Space Science, Volume 177, article id. 104695.
Copyright ©
(c) 2019 Elsevier Ltd

2019 October

Authors:
Hojjatpanah, S.; Figueira, P.; Santos, N. C.; Adibekyan, V.; Sousa, S. G.; Delgado-Mena, E.; Alibert, Y.; Cristiani, S.; González Hernández, J. I.; Lanza, A. F.; Di Marcantonio, P.; Martins, J. H. C.; Micela, G.; Molaro, P.; Neves, V.; Oshagh, M.; Pepe, F.; Poretti, E.; Rojas-Ayala, B.; Rebolo, R.; Suárez Mascareño, A.; Zapatero Osorio, M. R.
Publication:
Astronomy & Astrophysics, Volume 629, id.A80, 27 pp.

2019 August

Authors:
Jutzi, Martin
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1480

2019 August

Authors:
Burn, Remo; Marboeuf, Ulysse; Alibert, Yann; Benz, Willy
Publication:
Astronomy & Astrophysics, Volume 629, id.A64, 17 pp.

2019 August

Authors:
Schwartz, Stephen; Ballouz, Ronald-Louis; Asphaug, Erik; Barnouin, Olivier; Bennett, Carina; Burke, Keara; Connolly, Harold; Drouet d'Aubigny, Christian; Delbó, Marco; DellaGiustina, Daniella; Jawin, Erica; Jutzi, Martin; Molaro, Jamie; Michel, Patrick; Miyamoto, Hideaki; Pajola, Maurizio; Quillen, Alice; Rizk, Bashar; Walsh, Kevin; Lauretta, Dante
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1139

2019 August

Authors:
Gabriel, Travis S. J.; Asphaug, Erik; Jackson, Alan; Emsenhuber, Alexandre; Cambioni, Saverio; Reufer, Andreas; Jutzi, Martin; Benz, Willy
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-298

2019 August

Authors:
Ballantyne, Harry; Jutzi, Martin; Golabek, Gregor; Cheng, Kar Wai; Tackley, Paul
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1420

2019 August

Authors:
Michel, Patrick; Ballouz, Ronald-Louis; Barnouin, Olivier; Walsh, Kevin; Jutzi, Martin; Richardson, Derek; Schwartz, Stephen; Sugita, Seiji; Watanabe, Sei-ichiro; Miyamoto, Hirdy; Hirabayashi, Masatoshi; Bottke, William; Connolly, Harold, Jr.; Lauretta, Dante
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-245

2019 August

Authors:
Renaud, Joe; Henning, Wade; Saxena, Prabal; Mandell, Avi; Jutzi, Martin; Hurford, Terry
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1677

2019 August

Authors:
Burn, Remo; Emsenhuber, Alexandre; Alibert, Yann; Mordasini, Christoph; Schlecker, Martin
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1678

2019 August

Authors:
Arakawa, Sota; Shibaike, Yuhito
Publication:
Astronomy & Astrophysics, Volume 629, id.A106, 8 pp.

2019 August

Authors:
Alibert, Yann; Venturini, Julia
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-457

2019 August

Authors:
Shah, Oliver; Alibert, Yann; Helled, Ravit
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1771

2019 August

Authors:
Cheng, Kar Wai; Rozel, Antoine B.; Golabek, Gregor J.; Ballantyne, Harry; Jutzi, Martin; Tackley, Paul
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1447

2019 August

Authors:
Ševeček, P.; Brož, M.; Jutzi, M.
Publication:
Astronomy & Astrophysics, Volume 629, id.A122, 12 pp.

2019 August

Authors:
Luther, Robert; Boustie, Michel; Hebert, David; Jodar, Benjamin; Maindl, Thomas; Martellato, Elena; Raducan, Sabina; Schäfer, Christoph; Zagouri, Didier; Jutzi, Martin; Wünnemann, Kai; Burchell, Mark; Collins, Gareth; Davison, Tom; Güldemeister, Nicole; Gulde, Max; Michel, Patrick; Murdoch, Naomi; Ormö, Jens; Parisi, Gabriela
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1776

2019 August

Authors:
Brügger, Natacha; Burn, Remo; Coleman, Gavin; Alibert, Yann; Benz, Willy
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-498

2019 August

Authors:
Lichtenberg, Tim; Golabek, Gregor; Burn, Remo; Meyer, Michael; Alibert, Yann; Gerya, Taras; Mordasini, Christoph
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-114

2019 August

Authors:
Alibert, Y.; Venturini, J.
Publication:
Astronomy & Astrophysics, Volume 626, id.A21, 10 pp.

2019 May

Authors:
Bennett, David; Akeson, Rachel; Alibert, Yann; Anderson, Jay; Bachelet, Etienne; Beaulieu, Jean-Phillipe; Bhattacharya, Aparna; Boss, Alan; Bozza, Valerio; Bryson, Stephen; Buzasi, Derek; Novati, Sebastiano Calchi; Christiansen, Jessie; Domagal-goldman, Shawn D.; Endl, Michael; Fulton, Benjamin J.; Henderson, Calen B.; Gaudi, B. Scott; Johnson, Samson A.; Koshimoto, Naoki; Meyer, Michael; Mulders, Gijs D.; Mullally, Susan; Murray-Clay, Ruth; Nataf, David; Nielsen, Eric; Ngo, Henry; Pascucci, Ilaria; Penny, Matthew; Plavchan, Peter; Poleski, Radek; Ranc, Clement; Raymond, Sean N.; Rogers, Leslie; Sahlmann, Johannes; Sahu, Kailash C.; Schlieder, Joshua; Shvartzvald, Yossi; Sozzetti, Alessandro; Street, Rachel; Sumi, Takahiro; Suzuki, Daisuke; Zimmerman, Neil
Publication:
Astro2020: Decadal Survey on Astronomy and Astrophysics, science white papers, no. 505; Bulletin of the American Astronomical Society, Vol. 51, Issue 3, id. 505 (2019)

2019 April

Authors:
Bower, Dan J.; Wolf, Aaron S.; Sanan, Patrick; Jutzi, Martin; Rubie, David C.
Publication:
21st EGU General Assembly, EGU2019, Proceedings from the conference held 7-12 April, 2019 in Vienna, Austria, id.7244

2019 March

Authors:
Alibert, Y.
Publication:
Astronomy & Astrophysics, Volume 624, id.A45, 10 pp.

2019 March

Authors:
Ballantyne, Harry; Jutzi, Martin; Golabek, Gregor; Cheng, Kar Wai; Tackley, Paul
Publication:
21st EGU General Assembly, EGU2019, Proceedings from the conference held 7-12 April, 2019 in Vienna, Austria, id.9012

2019 March

Authors:
Hirabayashi, Masatoshi; Davis, Alex B.; Fahnestock, Eugene G.; Richardson, Derek C.; Michel, Patrick; Cheng, Andrew F.; Rivkin, Andrew S.; Scheeres, Daniel J.; Chesley, Steven R.; Yu, Yang; Naidu, Shantanu P.; Schwartz, Stephen R.; Benner, Lance A. M.; Pravec, Petr; Stickle, Angela M.; Jutzi, Martin; DART Dynamical Group; Physical Properties (WG3) Analysis Group
Publication:
Advances in Space Research, Volume 63, Issue 8, p. 2515-2534.
Copyright ©
(c) 2019 COSPAR

2019 March

Authors:
Michel, P.; Barnouin, O. S.; Ballouz, R. -L.; Walsh, K. J.; Richardson, D. C.; Schwartz, S. R.; Jutzi, M.; Sugita, S.; Watanabe, S.; Hirabayashi, M.; Miyamoto, H.; Bottke, W. F.; Connolly, H. C.; Lauretta, D. S.
Publication:
50th Lunar and Planetary Science Conference, held 18-22 March, 2019 at The Woodlands, Texas. LPI Contribution No. 2132, id.1659

2019 February

Authors:
Audard, Marc; Meyer, Michael R.; Alibert, Yann
Publication:
From Protoplanetary Disks to Planet Formation: Saas-Fee Advanced Course 45. Swiss Society for Astrophysics and Astronomy, Saas-Fee Advanced Course, Volume 45. ISBN 978-3-662-58686-0. Springer-Verlag GmbH Germany, part of Springer Nature, 2019
Copyright ©
(c) 2019: Springer-Verlag GmbH Germany, part of Springer Nature

2018 November

Authors:
Mishra, Lokesh; Alibert, Yann; Udry, Stephane
Publication:
EPSC-DPS Joint Meeting 2019, held 15-20 September 2019 in Geneva, Switzerland, id. EPSC-DPS2019-1616

2019 August

Authors:
Lichtenberg, Tim; Golabek, Gregor J.; Burn, Remo; Meyer, Michael; Alibert, Yann; Gerya, Taras; Mordasini, Christoph
Publication:
American Astronomical Society, Extreme Solar Systems 4, id. 311.01. Bulletin of the American Astronomical Society, Vol. 51, No. 6
Copyright ©
Copyright 2019 the American Astronomical Society

2019 July

Authors:
Lichtenberg, Tim; Golabek, Gregor J.; Burn, Remo; Meyer, Michael R.; Alibert, Yann; Gerya, Taras V.; Mordasini, Christoph
Publication:
21st EGU General Assembly, EGU2019, Proceedings from the conference held 7-12 April, 2019 in Vienna, Austria, id.5414

2019 March

Authors:
Lichtenberg, Tim; Golabek, Gregor J.; Burn, Remo; Meyer, Michael R.; Alibert, Yann; Gerya, Taras V.; Mordasini, Christoph
Publication:
Nature Astronomy, Volume 3, p. 307-313

2019 January

Authors:
Coleman, G. A. L.; Leleu, A.; Alibert, Y.; Benz, W.
Publication:
Astronomy & Astrophysics, Volume 631, id.A7, 24 pp.

2019 October

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