Search results for "SIP"
showing 10 items of 1280 documents
Optical bullets and "rockets" in nonlinear dissipative systems and their transformations and interactions
2006
We demonstrate the existence of stable optical light bullets in nonlinear dissipative media for both cases of normal and anomalous chromatic dispersion. The prediction is based on direct numerical simulations of the (3+1)-dimensional complex cubic-quintic GinzburgLandau equation. We do not impose conditions of spherical or cylindrical symmetry. Regions of existence of stable bullets are determined in the parameter space. Beyond the domain of parameters where stable bullets are found, unstable bullets can be transformed into >rockets> i.e. bullets elongated in the temporal domain. A few examples of the interaction between two optical bullets are considered using spatial and temporal interact…
Environmental effects on the natural vibrations of nanoplatelets: a high pressure study.
2017
International audience; Resonant acoustic modes from ultrathin CdS colloidal nanoplatelets (NPLs) are probed under high pressure using low frequency Raman spectroscopy. In particular we focus on the characterization of the recently evidenced mass load effect that is responsible for a significant downshift of the NPL breathing frequency due to the inert mass of organic ligands. We show that a key parameter in the observation of the mass effect is whether the surrounding medium is able to support THz acoustic wave propagation, at a frequency close to that of the inorganic vibrating core. At low pressures, surface organic molecules show a single particle-like behavior and a strong mass effect …
Molecular characterization of cyclic and obligate parthenogens in the aphid Rhopalosiphum padi (L.)
1996
Holocyclic clones of the aphid Rhopalosiphum padi (L.) reproduce by cyclic parthenogenesis, whereas anholocyclic individuals are obligate parthenogens. Mitochondrial DNA (mtDNA) and random amplified polymorphic DNA markers in R . padi as well as plasmid DNA markers of its bacterial endosymbiont, Buchnera aphidicola , were examined to determine the extent of genetic divergence between clones with these differing breeding systems. These analyses revealed that cyclically parthenogenetic lineages possessed differing mtDNA and plasmid haplotypes than most obligately asexual clones. The extent of sequence divergence between these maternally inherited molecules suggests a relatively ancient origin…
Etude des interactions plantes-microbes et microbes-microbes au sein de la rhizosphère, sous un aspect coûts-bénéfices, dans un contexte de variation…
2013
Understanding the interactions that bind plants and soil microorganisms is an essential step for the sustainable management of ecosystems, especially in agriculture. The ecosystem services resulting from such interactions include plant productivity which responds, in part, to the food requirements of the world's population and the regulation of biogeochemical cycles. These ecosystem services depend on trophic links between the two partners in the interaction and can be represented by a tradeoff between the costs and benefits for each partner. Plants, being autotrophic organisms or primary producers, are key organisms which introduce carbon into the ecosystem, through photosynthesis. Part of…
Response of soil bacterial communities to the incorporation of crop residues : influence of agricultural practices and link with the soil biological …
2010
The effect of the location of wheat residues (soil surface vs. incorporated in soil) on their decomposition and on soil bacterial communities was investigated by the means of a field experiment. Bacterial-Automated Ribosomal Intergenic Spacer Analysis (B-ARISA) of DNA extracts from residues, detritusphere (soil adjacent to residues), and bulk soil evidenced that residues constitute the zone of maximal changes in bacterial composition. However, the location of the residues influenced greatly their decomposition and the dynamics of the colonizing bacterial communities. Sequencing of 16S rRNA gene in DNA extracts from the residues at the early, middle, and late stages of degradation confirmed …
Response of soil bacterial communities to the incorporation of crop residues : influence of agricultural practices and link with the soil biological …
2010
The effect of the location of wheat residues (soil surface vs. incorporated in soil) on their decomposition and on soil bacterial communities was investigated by the means of a field experiment. Bacterial-Automated Ribosomal Intergenic Spacer Analysis (B-ARISA) of DNA extracts from residues, detritusphere (soil adjacent to residues), and bulk soil evidenced that residues constitute the zone of maximal changes in bacterial composition. However, the location of the residues influenced greatly their decomposition and the dynamics of the colonizing bacterial communities. Sequencing of 16S rRNA gene in DNA extracts from the residues at the early, middle, and late stages of degradation confirmed …
Effects of precipitation regime on soil bacterial and fungal activity upon rewetting of a plant-soil system using 18O-SIP: depth matters
2017
EASPEBIOmEDOCT INRA; Climate change is predicted to affect not only the amount but also the temporal distribution of rain. Changes in frequency and amplitude of rain events, likely shape the activity of plants and soil microbes. Fluctuating water conditions will differ with soil depth between precipitation patterns, affecting plant growth and may result in differential microbial response upon rewetting. Our objective was to investigate, in plant-soil systems, the response of the metabolically active microbial communities to a rewetting event and to which extent this was modulated by 1) soil depth and 2) precipitation legacy. Wheat planted in soil mesocosms were subjected to frequent or infr…
Arbuscular mycorrhiza (AM): the first glomeromycotan sugar transporter is characterized by using the unique geosiphon symbiosis with cyanobacteria to…
2007
International audience; In the arbuscular mycorrhizas (AM), the symbiotic interface is the site of nutrient exchange where the mycobiont receives up to 20% of the photosynthates of the photobiont as carbohydrates. We have, for the first time, functionally characterised a monosaccharide transporter type, represented by GpMST1, putatively playing a role in this process (Schüßler, A., Martin, H., Cohen, D., Fitz, M., and Wipf, D. 2006. Characterization of a carbohydrate transporter from symbiotic glomeromycotan fungi. Nature 444:933-936.). Together with the arbuscular mycorrhizal (AM) fungi, forming endomycorrhiza with the majority of land plants, Geosiphon pyriformis belongs to the Glomeromyc…
Apport de l'isotopie couplée aux outils de biologie moléculaire (DNA/RNA-SIP) pour caractériser la dynamique des communautés impliquées dans la dégra…
2008
L’opera del premio Nobel Giulio Natta fra le attività della Società Italiana per il Progresso delle Scienze (SIPS) e della Società Chimica Italiana (…
2013
In spite of its great historical and social-institutional importance, the Italian Society for the Progress of Sciences (SIPS) still have not that historical fame which it would deserve. This paper wishes to contribute to delineate a brief historic-critical account which may provide a coherent diachronic perspective in which historically laid out such an institution, highlighting the relevant load that it has had for the cultural, scientific and technological development of the post-Resurgence Italy. From this historical recognition, it will be then possible to descry a more or less direct role played by SIPS, around the first half of 20th Century, as concerns the research activity of the It…