Photoelectron Angular Distributions for Two-photon Ionization of Helium by Ultrashort Extreme Ultraviolet Free Electron Laser Pulses

Phase-shift differences and amplitude ratios of the outgoing $s$ and $d$ continuum wave packets generated by two-photon ionization of helium atoms are determined from the photoelectron angular distributions obtained using velocity map imaging. Helium atoms are ionized with ultrashort extreme-ultraviolet free-electron laser pulses with a photon energy of 20.3, 21.3, 23.0, and 24.3 eV, produced by the SPring-8 Compact SASE Source test accelerator. The measured values of the phase-shift differences are distinct from scattering phase-shift differences when the photon energy is tuned to an excited level or Rydberg manifold. The difference stems from the competition between resonant and non-resonant paths in two-photon ionization by ultrashort pulses. Since the competition can be controlled in principle by the pulse shape, the present results illustrate a new way to tailor the continuum wave packet.Comment: 5 pages, 1 table, 3 figure

ProSOM: core promoter prediction based on unsupervised clustering of DNA physical profiles

Motivation: More and more genomes are being sequenced, and to keep up with the pace of sequencing projects, automated annotation techniques are required. One of the most challenging problems in genome annotation is the identification of the core promoter. Because the identification of the transcription initiation region is such a challenging problem, it is not yet a common practice to integrate transcription start site prediction in genome annotation projects. Nevertheless, better core promoter prediction can improve genome annotation and can be used to guide experimental work

ISOL@: an Italian SOLAnaceae genomics resource

BACKGROUND: Present-day '-omics' technologies produce overwhelming amounts of data which include genome sequences, information on gene expression (transcripts and proteins) and on cell metabolic status. These data represent multiple aspects of a biological system and need to be investigated as a whole to shed light on the mechanisms which underpin the system functionality.The gathering and convergence of data generated by high-throughput technologies, the effective integration of different data-sources and the analysis of the information content based on comparative approaches are key methods for meaningful biological interpretations.In the frame of the International Solanaceae Genome Project, we propose here ISOLA, an Italian SOLAnaceae genomics resource. RESULTS: ISOLA (available at http://biosrv.cab.unina.it/isola) represents a trial platform and it is conceived as a multi-level computational environment.ISOLA currently consists of two main levels: the genome and the expression level. The cornerstone of the genome level is represented by the Solanum lycopersicum genome draft sequences generated by the International Tomato Genome Sequencing Consortium. Instead, the basic element of the expression level is the transcriptome information from different Solanaceae species, mainly in the form of species-specific comprehensive collections of Expressed Sequence Tags (ESTs).The cross-talk between the genome and the expression levels is based on data source sharing and on tools that enhance data quality, that extract information content from the levels' under parts and produce value-added biological knowledge. CONCLUSIONS: ISOLA is the result of a bioinformatics effort that addresses the challenges of the post-genomics era. It is designed to exploit '-omics' data based on effective integration to acquire biological knowledge and to approach a systems biology view. Beyond providing experimental biologists with a preliminary annotation of the tomato genome, this effort aims to produce a trial computational environment where different aspects and details are maintained as they are relevant for the analysis of the organization, the functionality and the evolution of the Solanaceae family

LA RÉPONSE IMMUNITAIRE DU JEUNE PORCELET

International audienc

Cleaning the GenBank Arabidopsis thaliana data set.

Data driven computational biology relies on the large quantities of genomic data stored in international sequence data banks. However, the possibilities are drastically impaired if the stored data is unreliable. During a project aiming to predict splice sites in the dicot Arabidopsis thaliana, we extracted a data set from the A.thaliana entries in GenBank. A number of simple 'sanity' checks, based on the nature of the data, revealed an alarmingly high error rate. More than 15% of the most important entries extracted did contain erroneous information. In addition, a number of entries had directly conflicting assignments of exons and introns, not stemming from alternative splicing. In a few cases the errors are due to mere typographical misprints, which may be corrected by comparison to the original papers, but errors caused by wrong assignments of splice sites from experimental data are the most common. It is proposed that the level of error correction should be increased and that gene structure sanity checks should be incorporated--also at the submitter level--to avoid or reduce the problem in the future. A non-redundant and error corrected subset of the data for A.thaliana is made available through anonymous FTP

Homocytotropic antibodies in the pig

International audienc

Les virus de l'artichaut. I.Mise en évidence de 3 virus dans les cultures françaises d'artichaut

Trois virus ont été isolés de l’artichaut dans les cultures de l’Ouest et du Sud-Est de la France : - Le virus latent de l’artichaut (ALV) appartenant au groupe des Potyvirus. Ce virus ne provoque pas de symptômes sur des artichauts de semis infectés mécaniquement ou par pucerons ; il peut néanmoins affecter la vigueur et la production des plantes. Les plantes régénérées sont rapidement recontaminées dans les conditions naturelles. - Le virus de la mosaïque du concombre (CMV), décrit pour la première fois sur artichaut induit sur cette espèce une mosaïque déformante et un rabougrissement. Les souches isolées en Bretagne et en Provence appartiennent au groupe symptomatologique B et sérologique To-Rs. - Un virus à particules isométriques de 28-30 nm qui pourrait s’apparenter au virus du flétrissement de la fève (BBwv) selon certains critères biologiques et ultra structuraux, mais qui n’a cependant pu être transmis par plusieurs espèces de pucerons. Les résultats ne permettent pas de relier ce virus aux autres virus isométriques décrits chez l’artichaut.Three viruses were isolated from artichoke plants cultivated in West and South-East France. Artichoke latent virus (ALV) belongs to the potyvirus group. This virus did not provoke symptoms on artichoke seedlings infected mechanically or by aphids ; nevertheless it did affect vigour and yield. Recontamination of healthy plants in natural conditions appeared to occur rapidly. Cucumber mosaic virus (CMV) was recorded for the first time from artichoke, inducing mosaic with deformation and stunting. The strains isolated so for in Brittany and Provence belonged to the symptomatological group B and serological group TO-RS. A virus with isometric particles 28-30 nm was found, with some relationships to broad bean wilt virus (BBWV) according to some biological and ultrastructural criteria but which could not be transmitted by several species of aphids. The results obtained do not allow the identification of this virus with any of the isometric viruses found in artichoke