Bertrand Lefebvre
University of New Hampshire
45 Papers
82 Citations
Bertrand Lefebvre is an academic researcher from University of New Hampshire. The author has contributed to research in topics: Ordovician & Geology. The author has an hindex of 17, co-authored 33 publications. Previous affiliations of Bertrand Lefebvre include Imperial College London & Queen Mary University of London.
Chat about Author
Papers
Are homalozoans echinoderms? An answer from the extraxial-axial theory
TL;DR: The Extraxial-Axial Theory (EAT) identifies body-wall homologies, common ontogenetic patterns, and major events in bodyplan evolution and strongly suggests that the bizarre asymmetry of homalozoans is a derived characteristic, and not indicative of plesiomorphic morphology for either chordates or echinoderms.
135
Evidence for newly closed magnetosheath field lines at the dayside magnetopause under northward IMF
Benoit Lavraud,Michelle F. Thomsen,Bertrand Lefebvre,Steven J. Schwartz,Kanako Seki,T. D. Phan,Y. L. Wang,A. N. Fazakerley,H. Rème,André Balogh +9 more
TL;DR: In this paper, the authors used 56 magnetopause encounters of Cluster spacecraft from 2001 to 2003 to explore the statistical properties of the magnetosheath electron boundary layer and its dependence on the magnetic field clock angle simultaneously measured by Cluster.
126
Laboratory Measurements of Electrostatic Solitary Structures Generated by Beam Injection
Bertrand Lefebvre,Li-Jen Chen,Walter Gekelman,Paul M. Kintner,Jolene S. Pickett,Patrick Pribyl,Stephen Vincena,Franklin Chiang,Jack W. Judy +8 more
TL;DR: Nonlinear wave packets of similar velocities and scales are observed, indicating that the two descend from the same mode which is consistent with the electrostatic whistler mode and result from an instability likely to be driven by field-aligned currents.
64
Electron Anisotropy Constraint in the Magnetosheath: Cluster Observations
S. P. Gary,Benoit Lavraud,Michelle F. Thomsen,Bertrand Lefebvre,Steven J. Schwartz +4 more
- 01 Dec 2006
TL;DR: In this paper, the authors show that electron anisotropies in two crossings of the dayside terrestrial magnetosheath are constrained statistically by this equation with S e ≃ 0.1? S e? 1 and 0.5? α e < 0.7 over 0.10 ≤ β∥ e < 1.
45
No (Cambrian) explosion and no (Ordovician) event: A single long-term radiation in the early Palaeozoic
Thomas Servais,Borja Cascales-Miñana,David A. T. Harper,Bertrand Lefebvre,Axel Munnecke,Wenhui Wang,Yuandong Zhang +6 more
TL;DR: In this paper , a review of biodiversity curves of marine organisms during the early Palaeozoic, including some based on data in the Paleobiology Database (PBDB) and the Geobiodiversity Database (GBDB), points towards a single, large-scale, long-term early Palaozoic radiation of life that already started in the late Precambrian.
42