25 research outputs found
Multi-gene phylogeny for Ophiostoma spp. reveals two new species from Protea infructescences
Ophiostoma represents a genus of fungi that are mostly
arthropod-dispersed and have a wide global distribution. The best known of
these fungi are carried by scolytine bark beetles that infest trees, but an
interesting guild of Ophiostoma spp. occurs in the infructescences of
Protea spp. native to South Africa. Phylogenetic relationships
between Ophiostoma spp. from Protea infructescences were
studied using DNA sequence data from the β-tubulin, 5.8S ITS (including
the flanking internal transcribed spacers 1 and 2) and the large subunit DNA
regions. Two new species, O. phasma sp. nov. and O.
palmiculminatum sp. nov. are described and compared with other
Ophiostoma spp. occurring in the same niche. Results of this study
have raised the number of Ophiostoma species from the infructescences
of serotinous Protea spp. in South Africa to five. Molecular data
also suggest that adaptation to the Protea infructescence niche by
Ophiostoma spp. has occurred independently more than once
Hybrid III-V on silicon lasers for photonic integrated circuits on silicon
This paper summarizes recent advances of integrated hybrid InP/SOI lasers and transmitters based on wafer bonding. At first the integration process of III-V materials on silicon is described. Then the paper reports on the results of single wavelength distributed Bragg reflector lasers with Bragg gratings etched on silicon waveguides. We then demonstrate that, thanks to the high-quality silicon bend waveguides, hybrid III-V/Si lasers with two integrated intra-cavity ring resonators can achieve a wide thermal tuning range, exceeding the C band, with a side mode suppression ratio higher than 40 dB. Moreover, a compact array waveguide grating on silicon is integrated with a hybrid III-V/Si gain section, creating a wavelength-selectable laser source with 5 wavelength channels spaced by 400 GHz. We further demonstrate an integrated transmitter with combined silicon modulators and tunable hybrid III-V/Si lasers. The integrated transmitter exhibits 9 nm wavelength tunability by heating an intra-cavity ring resonator, high extinction ratio from 6 to 10 dB, and excellent bit-error-rate performance at 10 Gb/s
<i>Oppida</i>, formes de l’habitat et culture matérielle su second âge du Fer dans le Gers et ses marges
National audienc
Anticipations et ajustements dans la demande de consommation et d'actifs financiers
SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : AR 13807 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
La question de l'identification des echelles d'equivalence : une estimation du cout de l'enfant sur des donnees de panel
SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : RP 17030 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc