Primavera 1999

Soliton signals caused by second order nonlinearity and their generation are addressed. Our numerical simulations confirm their importance for various applications in many photonic devices, such as the second harmonic generation and the parametric amplification in single pass or intracavity setups. In particular, the role of modulational instabilities in the generation, as well as the behaviour and robustness of the soliton signals under the influence of gain and loss at different frequency bands is taken into account and related to their experimental counterpart and already existing data.

Internet ha significado no solo un nuevo modelo de comunicación en todos los sectores y actividades. También en el propio campo tecnológico supone una profunda reconversión en cómo se han de implantar los sistemas y diseñar y programar las aplicaciones. ¿Están los prefesionales preparados para asumir este reto?

Much effort is currently invested into making gene prediction more accurate. Traditionally, techniques such as analyzing sequence composition statistics or homology searches with the help of protein or EST databases, are employed. Only recently, with the launch of projects for comparative genomic sequencing, a novel method for prediction of exons, genes and regulatory elements became available.

Gapped alignments of homologous genomic sequences of different species at the appropriate phylogenetic distance usually show a patchwork pattern of conserved and less conserved fragments -the so- called phylogenetic footprint. Simple filtering based on fragment length and match percentage retrieves a subset of candidate exons. To optimize filter parameters we extracted samples of annotated homologous man/rodent genomic sequences from GenBank. We show that by optimized filtering of alignments alone one can achieve an approximate correlation (AC) value of predicted and true exons of at least 0.73 a value which is in the range of that by customary prediction of complete gene models, candidate exons are corrected such that the quality of the sequence signals and the similarity of the predicted amino acid sequences are maximized.

The examples studied in Man, Mouse and Fugu suggest that simirality based gene prediction may become a valid alternative to the more conventional methods.

Within the framework of the hyperspherical approach to reaction dynamics, we have developed and implemented a new method, that we have called hyperquantization algorithm to solve exactly the quantum mechanical three-atom reactive scattering problem. The most important ingredients of this algorithm are generalized 3j symbols or Hahn Polynomials which are the discrete analogs of hyperspherical harmonics on a grid of points. The use of sequential diagonalization-truncation thecniques to diagonalize the Hamiltonian matrix makes this method very efficient and competitive with respect to the existing ones.
Calculations of state-to-state reactive cross sections for the reaction He + H₂⁺ -