Antoine Levy

© 2016 International Society for Microbial Ecology All rights reserved.Over the past decade, high-throughput short-read 16S rRNA gene amplicon sequencing has eclipsed clone-dependent long-read Sanger sequencing for microbial community profiling. The transition to new technologies has provided more quantitative information at the expense of taxonomic resolution with implications for inferring metabolic traits in various ecosystems. We applied single-molecule real-time sequencing for microbial community profiling, generating full-length 16S rRNA gene sequences at high throughput, which we propose to name PhyloTags. We benchmarked and validated this approach using a defined microbial community. When further applied to samples from the water column of meromictic Sakinaw Lake, we show that while community structures at the phylum level are comparable between PhyloTags and Illumina V4 16S rRNA gene sequences, variance increases with community complexity at greater water depths. PhyloTags moreover allowed less ambiguous classification. Last, a platform-independent comparison of PhyloTags and in silico generated partial 16S rRNA gene sequences demonstrated significant differences in community structure and phylogenetic resolution across multiple taxonomic levels, including a severe underestimation in the abundance of specific microbial genera involved in nitrogen and methane cycling across the Lake's water column. Thus, PhyloTags provide a reliable adjunct or alternative to cost-effective iTags, enabling more accurate phylogenetic resolution of microbial communities and predictions on their metabolic potential.

© 2016. The American Astronomical Society. All rights reserved.We present DES14X3taz, a new hydrogen-poor superluminous supernova discovered by the Dark Energy Survey supernova program, with additional photometric data provided by the Survey Using DECam for Superluminous Supernovae. Spectra obtained using Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy on the Gran Telescopio CANARIAS show DES14X3taz is an SLSN-I at z = 0.608. Multi-color photometry reveals a double-peaked light curve: a blue and relatively bright initial peak that fades rapidly prior to the slower rise of the main light curve. Our multi-color photometry allows us, for the first time, to show that the initial peak cools from 22,000 to 8000 K over 15 rest-frame days, and is faster and brighter than any published core-collapse supernova, reaching 30% of the bolometric luminosity of the main peak. No physical 56Ni-powered model can fit this initial peak. We show that a shock-cooling model followed by a magnetar driving the second phase of the light curve can adequately explain the entire light curve of DES14X3taz. Models involving the shock-cooling of extended circumstellar material at a distance of ≃400 R⊙ are preferred over the cooling of shock-heated surface layers of a stellar envelope. We compare DES14X3taz to the few double-peaked SLSN-I events in the literature. Although the rise times and characteristics of these initial peaks differ, there exists the tantalizing possibility that they can be explained by one physical interpretation.

La reception du christianisme byzantin par l'Eglise catholique presente une sorte d'anomalie. Invoquant l'autorite de Thomas d'Aquin, les theologiens occidentaux rejettent generalement l'idee d'une distinction reelle entre l'essence et les energies divines, tout comme la notion de grace increee, laquelle joue un role essentiel dans la vision de Gregoire Palamas (XIVe siecle). D'un autre cote, ces memes theologiens ont ete nombreux a redecouvrir, durant la periode recente, la pensee de Maxime le Confesseur (VIIe siecle), voyant en celui-ci un genial precurseur de Thomas d'Aquin. Or que resterait-il de la doctrine de Gregoire Palamas sans le patronage de Maxime le Confesseur? Comment meconnaitre l'un et reconnaitre l'autre au nom du meme Thomas d'Aquin? Ce qui vient ici au jour a travers l'etude des contextes et des enjeux doctrinaux, c'est la coexistence, jusqu'alors insoupconnee, de deux representations distinctes du rapport entre le cree et l'incree. L'Occident latin et l'Orient byzantin n'en finissent pas de comprendre differemment cette foi qui leur est pourtant indiscutablement commune.