Multifractal characterisation of length sequences of coding and noncoding segments in a complete genome

The coding and noncoding length sequences constructed from a complete genome are characterised by multifractal analysis. The dimension spectrum $D_{q}$ and its derivative, the 'analogous' specific heat $C_{q}$, are calculated for the coding and noncoding length sequences of bacteria, where $q$ is the moment order of the partition sum of the sequences. From the shape of the $$ and $C_{q}$ curves, it is seen that there exists a clear difference between the coding/noncoding length sequences of all organisms considered and a completely random sequence. The complexity of noncoding length sequences is higher than that of coding length sequences for bacteria. Almost all $D_{q}$ curves for coding length sequences are flat, so their multifractality is small whereas almost all $D_{q}$ curves for noncoding length sequences are multifractal-like. We propose to characterise the bacteria according to the types of the $C_{q}$ curves of their noncoding length sequences.Comment: 15 pages with 5 figures, Latex, Accepted for publication in Physica

EST databases as multi-conditional gene expression datasets

Large-scale expression data, such as that generated by hybridization to microarrays, is potentially a rich source of information on gene function and regulation. By clustering genes according to their expression profiles, groups of genes involved in the same pathways or sharing common regulatory mechanisms may be identified. Publicly-available EST collections are a largely unexplored source of expression data. We previously used a sample of rice ESTs to generate 'digital expression profiles' by counting the frequency of tags for different genes sequenced from different cDNA libraries. A simple statistical test was used to associate genes or cDNA libraries having similar expression profiles. Here we further validate this approach using larger samples of ESTs from the UniGene projects (clustered human, mouse and rat ESTs). Our results show that genes clustered on the basis of expression profile may represent genes implicated in similar pathways or coding for different subunits of multi-component enzyme complexes. In addition we suggest that comparison of clusters from different species, may be useful for confirmation or prediction of orthologs

The effects of bending on the growth and fruit production on INRA fercer sweet cherry

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Comparative analysis of the Arabidopsis and rice expressed sequence tag (EST) sets

Large numbers of expressed sequence tags (ESTs) have now been generated from a variety of model organisms. In plants, substantial collections of ESTs are available for Arabidopsis and rice, in each case representing significant proportions of the estimated total numbers of genes. Large-scale comparisons of Arabidopsis and rice sequences are especially interesting due to the fact that these two species are representatives of the two subclasses of the flowering plants (Dicotyledonae and Monocotyledonae, respectively). Here we present the results of systematic analysis of the Arabidopsis and rice EST sets. Non-redundant sets of sequences from Arabidopsis and rice were first separately derived and then combined so that gene families in common between the two species could be identified. Our results show that 58% of non-singleton ESTs are derived from genes in gene families common to the two species. These gene families constitute the basis of a core set of higher plant genes

Dispersion of calcite by poly(sodium acrylate) prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization

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Optical sensor for characterizing the phase transition in salted solutions

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Water-ice phase transition probed by Raman spectroscopy

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SiGe virtual substrates growth up to 50% Ge concentration for Si/Ge dual channel epitaxy

International audienceWe have grown in reduced pressure–chemical vapor deposition (RP-CVD) SiGe virtual substrates with Ge concentrations ranging from 20 up to 50%. We have observed an increase of the surface rms roughness with the final Ge content of the virtual substrates. Cross sectional transmission electron microscopy images revealed an effective confinement of the misfit dislocations inside the graded buffer. The final Ge content of the virtual substrate has no impact on the field threading dislocations density, whereas an increase of the pile-up threading dislocations density occurred. We have then used Si0.49Ge0.51 virtual substrates as templates for the growth of Si/Ge dual channels. Although some dislocations were observed, mainly in the silicon layer, we have demonstrated the growth feasibility of such highly mismatched heterostructures in RP-CVD