François Robert – författare

This volume, number 16 in the Space Sciences Series of ISSI, reviews the present knowledgeonmanyaspectsofthehistoryofthesolarsystem. Itfocuses onisotopic signatures ofvolatile elements as tracers for the evolutionary processes during the formation of the Sun and the planets from an interstellar molecular cloud and, in tum, illuminates how the isotopic compositions of present-day solar system ob- jects had been established. This integrated collection of articles complements the information provided by previous ISSI volumes such as From Dust to Terrestrial Planets and Chronology and Evolution of Mars, expanding the time scale for the history ofthe solar system. The convenors, Therese Encrenaz, Observatoire de Paris, Meudon; Johannes Geiss, ISSI, Bern; Reinald Kallenbach, ISSI, Bern; Konrad Mauersberger, Max- Planck-Institut fUr Kernphysik, Heidelberg; Tobias Owen, University of Hawaii, Honolulu; and Fran~ois Robert, CNRS-Museum d'Histoire Naturelle, Paris, in- vited experts in planetary science, solar and heliospheric physics, astrophysics, mineralogy, and chemistry to an interdisciplinary workshop in Bern, 14-18 Jan- uary 2002.The resulting review articles are grouped into four sections 'Sun and Protosolar Nebula', 'Outer Solar System', 'Earth, Terrestrial Planets, and Moon', and 'Isotopic FractionationProcesses'.

Astrobiology, a new exciting interdisciplinary research field, seeks to unravel the origin and evolution of life wherever it might exist in the Universe. The current view of the origin of life on Earth is that it is strongly connected to the origin and evolution of our planet and, indeed, of the Universe as a whole. We are fortunate to be living in an era where centuries of speculation about the two ancient and fundamental problems: the origin of life and its prevalence in the Universe are being replaced by experimental science. The subject of Astrobiology can be approached from many different perspectives. This book is focused on abiogenic organic matter from the viewpoint of astronomy and planetary science and considers its potential relevance to the origins of life on Earth and elsewhere. Guided by the review papers in this book, the concluding chapter aims to identify key questions to motivate future research and stimulate astrobiological applications of current and future research facilities and space missions. Today’s rich array of new spacecraft, telescopes and dedicated scientists promises a steady flow of discoveries and insights that will ultimately lead us to the answers we seek.

Astrobiology, a new exciting interdisciplinary research field, seeks to unravel the origin and evolution of life wherever it might exist in the Universe. The current view of the origin of life on Earth is that it is strongly connected to the origin and evolution of our planet and, indeed, of the Universe as a whole. We are fortunate to be living in an era where centuries of speculation about the two ancient and fundamental problems: the origin of life and its prevalence in the Universe are being replaced by experimental science. The subject of Astrobiology can be approached from many different perspectives. This book is focused on abiogenic organic matter from the viewpoint of astronomy and planetary science and considers its potential relevance to the origins of life on Earth and elsewhere. Guided by the review papers in this book, the concluding chapter aims to identify key questions to motivate future research and stimulate astrobiological applications of current and future research facilities and space missions. Today’s rich array of new spacecraft, telescopes and dedicated scientists promises a steady flow of discoveries and insights that will ultimately lead us to the answers we seek.

Un système dynamique discret est un ensemble fini d'éléments, prenant chacun un nombre fini d'états, et evoluant, dans un temps discret, par interactions mutuelles. Ce livre est consacré a l'analyse de la dynamique temporelle de tels systèmes. Grâce à des outils de métrique discrète, on établit des résultats de convergence globale (contraction booléenne) convergence locale vers un point fixe ou vers un cycle, et ceci pour différents modes opératoires (parallèle, série, série-parallèle, chaotique). Le contenu de ce livre, où chaque résultat est illustré par un ou plusieurs exemples incluant de nombreux diagrammes, veut intéresser aussi bien des étudiants ingénieurs, chercheurs en mathématiques appliquées que des informaticiens connexionistes, des automaticiens et des physiciens.

a c 9 h In presenting this monograph, I would like to indicate both its orientation as well as my personal reasons for being interested in discrete iterations (that is, iterations on a generally very large,jinite set). While working in numerical analysis I have been interested in two main aspects: - the algorithmic aspect: an iterative algorithm is a mathematical entity which behaves in a dynamic fashion. Even if it is started far from a solution, it will often tend to get closer and closer. - the mathematical aspect: this consists of a coherent and rigorous analy­ sis of convergence, with the aid of mathematical tools (these tools are mainly the use of norms for convergence proofs, the use of matrix algebra and so on). One may for example refer to the algorithmic and mathematical aspects of Newton's method in JRn as well as to the QR algorithm for eigenvalues of matrices. These two algorithms seem to me to be the most fascinating algorithms in numerical analysis, since both show a remarkable practical efficiency even though there exist relatively few global convergence results for them.