Problemática del txistu

El txistu, nuestro típico y ancestral instrumento, símbolo del sentir musical del pueblo vasco, íntimamente unido a su desarrollo, ha adquirido gran popularidad a través de las melodías ejecutadas por txistularis en romerías, danzas populares pero existe un escaso conocimiento del txistu de concierto. Actualmente se está llevando a cabo un movimiento de renovación del ambiente txistulari (mejora técnica de los instrumentos, aumento de la familia instrumental del txistu). El aspecto pedagógico del txistu necesita una estructuración urgente en sus sistemas y enseñanzas. El txistu puede servir a nuestra música de muy diversas formas. El rústico txistu se adentra en el terreno experimental con una doble problemática: técnica y emocional (adaptando nuestra mentalidad ante los aires renovadores del instrumento). Ha llegado la hora de apreciar nuevas sonoridades, técnicas nuevas, concertar el txistu con otros instrumentos, componer partituras originales, perfeccionar a los alumnos txistularis. El mantenimiento y progreso del txistu compete a todo

Uncovering Proximity of Chromosome Territories using Classical Algebraic Statistics

Exchange type chromosome aberrations (ETCAs) are rearrangements of the genome that occur when chromosomes break and the resulting fragments rejoin with other fragments from other chromosomes. ETCAs are commonly observed in cancer cells and in cells exposed to radiation. The frequency of these chromosome rearrangements is correlated with their spatial proximity, therefore it can be used to infer the three dimensional organization of the genome. Extracting statistical significance of spatial proximity from cancer and radiation data has remained somewhat elusive because of the sparsity of the data. We here propose a new approach to study the three dimensional organization of the genome using algebraic statistics. We test our method on a published data set of irradiated human blood lymphocyte cells. We provide a rigorous method for testing the overall organization of the genome, and in agreement with previous results we find a random relative positioning of chromosomes with the exception of the chromosome pairs \{1,22\} and \{13,14\} that have a significantly larger number of ETCAs than the rest of the chromosome pairs suggesting their spatial proximity. We conclude that algebraic methods can successfully be used to analyze genetic data and have potential applications to larger and more complex data sets

A Liquid Crystal Model of Viral DNA Encapsidation

A liquid crystal continuum modeling framework for icosahedra bacteriophage viruses is developed and tested. The main assumptions of the model are the chromonic columnar hexagonal structure of confined DNA, the high resistance to bending and the phase transition from solid to fluid-like states as the concentration of DNA in the capsid decreases during infection. The model predicts osmotic pressure inside the capsid and the ejection force of the DNA as well as the size of the isotropic volume at the center of the capsid. Extensions of the model are discussed

Fine Structure of Viral dsDNA Encapsidation

In vivo configurations of dsDNA of bacteriophage viruses in a capsid are known to form hexagonal chromonic liquid crystal phases. This article studies the liquid crystal ordering of viral dsDNA in an icosahedral capsid, combining the chromonic model with that of liquid crystals with variable degree of orientation. The scalar order parameter of the latter allows us to distinguish regions of the capsid with well-ordered DNA from the disordered central core. We employ a state-of-the-art numerical algorithm based on the finite element method to find equilibrium states of the encapsidated DNA and calculate the corresponding pressure. With a data-oriented parameter selection strategy, the method yields phase spaces of the pressure and the radius of the disordered core, in terms of relevant dimensionless parameters, rendering the proposed algorithm into a preliminary bacteriophage designing tool. The presence of the order parameter also has the unique role of allowing for non-smooth capsid domains as well as accounting for knot locations of the DNA

Topology of viral DNA

Chromosome organization plays a key role in many biological processes. In viruses genome organization is essential for the packaging and releasing of the genome as well as for maintaining the stability of the viral capsid. This organization varies across different families and is highly dependent on the virus morphogenetic pathway (Casjens, 1997). In this review we will focus on the packing of double stranded DNA (dsDNA) in bacteriophages. Understanding how dsDNA is packed in bacteriophage capsids is important because it arguably yields the simplest example of a full genome organization in a biological system. Furthermore bacteriophages are believed to pack their DNA similarly to some animal viruses such as herpes and adeno-viruses (Casjens, 1997). Therefore understanding the basic principles of DNA packing in bacteriophages may provide essential insights into the viral assembly pathways for a wide range of bacterial and animal viruses.J. Arsuaga is supported by NIH grant 2S06GM52588–12.Peer Reviewe

The Rabl configuration limits topological entanglement of chromosomes in budding yeast.

The three dimensional organization of genomes remains mostly unknown due to their high degree of condensation. Biophysical studies predict that condensation promotes the topological entanglement of chromatin fibers and the inhibition of function. How organisms balance between functionally active genomes and a high degree of condensation remains to be determined. Here we hypothesize that the Rabl configuration, characterized by the attachment of centromeres and telomeres to the nuclear envelope, helps to reduce the topological entanglement of chromosomes. To test this hypothesis we developed a novel method to quantify chromosome entanglement complexity in 3D reconstructions obtained from Chromosome Conformation Capture (CCC) data. Applying this method to published data of the yeast genome, we show that computational models implementing the attachment of telomeres or centromeres alone are not sufficient to obtain the reduced entanglement complexity observed in 3D reconstructions. It is only when the centromeres and telomeres are attached to the nuclear envelope (i.e. the Rabl configuration) that the complexity of entanglement of the genome is comparable to that of the 3D reconstructions. We therefore suggest that the Rabl configuration is an essential player in the simplification of the entanglement of chromatin fibers

Orientation of DNA Minicircles Balances Density and Topological Complexity in Kinetoplast DNA

Kinetoplast DNA (kDNA), a unique mitochondrial structure common to trypanosomatid parasites, contains thousands of DNA minicircles that are densely packed and can be topologically linked into a chain mail-like network. Experimental data indicate that every minicircle in the network is, on average, singly linked to three other minicircles (i.e., has mean valence 3) before replication and to six minicircles in the late stages of replication. The biophysical factors that determine the topology of the network and its changes during the cell cycle remain unknown. Using a mathematical modeling approach, we previously showed that volume confinement alone can drive the formation of the network and that it induces a linear relationship between mean valence and minicircle density. Our modeling also predicted a minicircle valence two orders of magnitude greater than that observed in kDNA. To determine the factors that contribute to this discrepancy we systematically analyzed the relationship between the topological properties of the network (i.e., minicircle density and mean valence) and its biophysical properties such as DNA bending, electrostatic repulsion, and minicircle relative position and orientation. Significantly, our results showed that most of the discrepancy between the theoretical and experimental observations can be accounted for by the orientation of the minicircles with volume exclusion due to electrostatic interactions and DNA bending playing smaller roles. Our results are in agreement with the three dimensional kDNA organization model, initially proposed by Delain and Riou, in which minicircles are oriented almost perpendicular to the horizontal plane of the kDNA disk. We suggest that while minicircle confinement drives the formation of kDNA networks, it is minicircle orientation that regulates the topological complexity of the network

Sobre la situación de los servicios psiquiátricos de la provincia de Alicante.

Con motivo de la solicitud realizada por un grupo de profesionales de los servicios psiquiátricos de la Diputación de Alicante, en la que señalaban una serie de dificultades en el proceso de integración y reforma de la salud mental, la Junta Directiva de la AEN acordó formar una comisión que se desplazase a Alicante con objeto de valorar, sobre el terreno, la situación de dichos servicios. Dos miembros de la Comisión de Asistencia nos desplazamos a Alicante y Valencia para intentar conocer directamente el funcionamiento de los servicios y mantener varias entrevistas con todas las partes relacionadas con los mismos

Sobre la situación de los servicios psiquiátricos de la provincia de Alicante.

Con motivo de la solicitud realizada por un grupo de profesionales de los servicios psiquiátricos de la Diputación de Alicante, en la que señalaban una serie de dificultades en el proceso de integración y reforma de la salud mental, la Junta Directiva de la AEN acordó formar una comisión que se desplazase a Alicante con objeto de valorar, sobre el terreno, la situación de dichos servicios. Dos miembros de la Comisión de Asistencia nos desplazamos a Alicante y Valencia para intentar conocer directamente el funcionamiento de los servicios y mantener varias entrevistas con todas las partes relacionadas con los mismos