La muerte de Martín Fierro, de Leonardo Castellani : apuntes de genética textual

En 1953, el padre Leonardo Castellani publica La muerte de Martín Fierro, un poema autobiográfico que remeda el estilo y forma del texto de José Hernández. Hemos hallado una copia mecanografiada -presumiblemente la misma que fuera entregada a la imprenta-, con numerosas correcciones autógrafas, algunas de las cuales no han sido incorporadas al texto finalmente editado. Destacamos dos tipos de variantes: aquellas que obedecen a cuestiones estilísticas (imitación del estilo gauchesco, mejoramiento de la métrica, signos de puntuación, etc.), y otras de mayor interés (reescritura y/o supresión de versos y estrofas completas) en las que se revela cierta autocensura ejercida sobre asuntos estrictamente relacionados con su crisis personal luego de haber sido expulsado de la Compañía de Jesús.

Lo que guardan los libros : La biblioteca de don Claudio Sánchez Albornoz

Frente a bibliotecas y archivos de referencia ineludible por la riqueza de sus materiales, conviven repositorios documentales más pequeños y virtualmente intonsos, como la Biblioteca del Centro Argentino de Estudios Históricos "Claudio Sánchez Albornoz", actual sede del Seminario de Edición y Crítica Textual "Germán Orduna", que conserva parte de la biblioteca del mencionado historiador. Un examen de los volúmenes que la componen permite testimoniar amistades, relaciones profesionales y modos de lectura y comentario de quien fuera presidente de la República Española en el exilio y uno de los fundadores de los estudios históricos sobre la Edad Media en la Argentina

Cuentos medievales : "La dama del castillo del gavilán" y el "Ejemplo de las flechas" Juan de Mandevilla, Libro de las maravillas del mundo

A partir de los últimos estudios acerca de la cuentística medieval, tendientes a ampliar el corpus de relatos insertos no sólo en colecciones de cuentos sino en textos muy variados, se rastrean y clasifican los incluidos en el Libro de las maravillas del mundo de Juan de Mandevilla. Asimismo, se realiza el análisis puntual de dos cuentos: "La dama del castillo del gavilán" y el "Ejemplo de las flechas".

Ecdótica e iconografía : Reflexiones sobre el arte de editar textos con imágenes

A raíz de la incorporación del corpus iconográfico en nuestra edición crítica de los cinco impresos castellanos del siglo XVI del Libro de las maravillas del mundo, de Juan de Mandevilla (2011), advertimos la conveniencia de reproducir y estudiar las imágenes que acompañaban los textos durante la Edad Media y las primeras décadas de la imprenta. Dar cuenta de las variantes xilográficas en el aparato crítico, impulsar la filiación de las miniaturas y grabados, vincular la labor de impresores a través del uso de determinadas imágenes y recoger los simbolismos que guarda el lenguaje icónico se vuelve un objetivo cada vez más necesario. A través de ejemplos tomados de diversas ediciones de textos ilustrados con imágenes pretendemos reflexionar sobre esta cuestión, aún muy poco debatida

Extraños en la casa : Alteridad y representaciones ficcionales en la literatura española (siglos XIII a XVII)

Tabla de contenidos: La alteridad necesaria / Gloria B. Chicote. Pero que d'outra lei sejan : Una vez más sobre los moros y los judíos en las Cantigas de Santa María de Alfonso X / Santiago Disalvo. El motivo de los hombres salvajes en El Victorial / Santiago Pérez. Católicos y protestantes en la Cueva de San Patricio : El purgatorio en la contienda contrarreformista según el Ms. BNM 18723 / María Mercedes Rodríguez Temperley. Purgatorio de San Patricio, en Irlanda [Biblioteva Nacional de Madrid, Ms. 18723] : Edición crítica y comentarios / María Mercedes Rodríguez Temperley. Disputa de alteridades en el Romancero / Gloria B. Chicote. Las otras voces en la Historia verdadera de la conquista de la Nueva España de Bernal Díaz del Castillo / Ely V. Di Croce. Identidad, otredad y nuevas representaciones ficcionales en el Lazarillo de Tormes / Cecilia Pavón.

Presentación

Fil: Rodríguez Temperley, María Mercedes. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

La muerte de Martín Fierro, de Leonardo Castellani : apuntes de genética textual

En 1953, el padre Leonardo Castellani publica La muerte de Martín Fierro, un poema autobiográfico que remeda el estilo y forma del texto de José Hernández. Hemos hallado una copia mecanografiada -presumiblemente la misma que fuera entregada a la imprenta-, con numerosas correcciones autógrafas, algunas de las cuales no han sido incorporadas al texto finalmente editado. Destacamos dos tipos de variantes: aquellas que obedecen a cuestiones estilísticas (imitación del estilo gauchesco, mejoramiento de la métrica, signos de puntuación, etc.), y otras de mayor interés (reescritura y/o supresión de versos y estrofas completas) en las que se revela cierta autocensura ejercida sobre asuntos estrictamente relacionados con su crisis personal luego de haber sido expulsado de la Compañía de Jesús.

Seawater carbonate chemistry and biological processes of oysters Crassostrea virginica during experiments, 2010

Estuarine organisms are exposed to periodic strong fluctuations in seawater pH driven by biological carbon dioxide (CO2) production, which may in the future be further exacerbated by the ocean acidification associated with the global rise in CO2. Calcium carbonate-producing marine species such as mollusks are expected to be vulnerable to acidification of estuarine waters, since elevated CO2 concentration and lower pH lead to a decrease in the degree of saturation of water with respect to calcium carbonate, potentially affecting biomineralization. Our study demonstrates that the increase in CO2 partial pressure (pCO2) in seawater and associated decrease in pH within the environmentally relevant range for estuaries have negative effects on physiology, rates of shell deposition and mechanical properties of the shells of eastern oysters Crassostrea virginica (Gmelin). High CO2 levels (pH ~7.5, pCO2 ~3500 µatm) caused significant increases in juvenile mortality rates and inhibited both shell and soft-body growth compared to the control conditions (pH ~8.2, pCO2 ~380 µatm). Furthermore, elevated CO2 concentrations resulted in higher standard metabolic rates in oyster juveniles, likely due to the higher energy cost of homeostasis. The high CO2 conditions also led to changes in the ultrastructure and mechanical properties of shells, including increased thickness of the calcite laths within the hypostracum and reduced hardness and fracture toughness of the shells, indicating that elevated CO2 levels have negative effects on the biomineralization process. These data strongly suggest that the rise in CO2 can impact physiology and biomineralization in marine calcifiers such as eastern oysters, threatening their survival and potentially leading to profound ecological and economic impacts in estuarine ecosystems.

DNA alignment and Bayesian trees of partial sequences of COI, COIII and the haemocyanin functional unit f-g of 28 octopod species

Background: Octopods have successfully colonised the world's oceans from the tropics to the poles. Yet, successful persistence in these habitats has required adaptations of their advanced physiological apparatus to compensate impaired oxygen supply. Their oxygen transporter haemocyanin plays a major role in cold tolerance and accordingly has undergone functional modifications to sustain oxygen release at sub-zero temperatures. However, it remains unknown how molecular properties evolved to explain the observed functional adaptations. We thus aimed to assess whether natural selection affected molecular and structural properties of haemocyanin that explains temperature adaptation in octopods. Results: Analysis of 239 partial sequences of the haemocyanin functional units (FU) f and g of 28 octopod species of polar, temperate, subtropical and tropical origin revealed natural selection was acting primarily on charge properties of surface residues. Polar octopods contained haemocyanins with higher net surface charge due to decreased glutamic acid content and higher numbers of basic amino acids. Within the analysed partial sequences, positive selection was present at site 2545, positioned between the active copper binding centre and the FU g surface. At this site, methionine was the dominant amino acid in polar octopods and leucine was dominant in tropical octopods. Sites directly involved in oxygen binding or quaternary interactions were highly conserved within the analysed sequence. Conclusions: This study has provided the first insight into molecular and structural mechanisms that have enabled octopods to sustain oxygen supply from polar to tropical conditions. Our findings imply modulation of oxygen binding via charge-charge interaction at the protein surface, which stabilize quaternary interactions among functional units to reduce detrimental effects of high pH on venous oxygen release. Of the observed partial haemocyanin sequence, residue 2545 formed a close link between the FU g surface and the active centre, suggesting a role as allosteric binding site. The prevalence of methionine at this site in polar octopods, implies regulation of oxygen affinity via increased sensitivity to allosteric metal binding. High sequence conservation of sites directly involved in oxygen binding indicates that functional modifications of octopod haemocyanin rather occur via more subtle mechanisms, as observed in this study.

Structures of two molluscan hemocyanin genes: Significance for gene evolution

We present here the description of genes coding for molluscan hemocyanins. Two distantly related mollusks, Haliotis tuberculata and Octopus dofleini, were studied. The typical architecture of a molluscan hemocyanin subunit, which is a string of seven or eight globular functional units (FUs, designated a to h, about 50 kDa each), is reflected by the gene organization: a series of eight structurally related coding regions in Haliotis, corresponding to FU-a to FU-h, with seven highly variable linker introns of 174 to 3,198 bp length (all in phase 1). In Octopus seven coding regions (FU-a to FU-g) are found, separated by phase 1 introns varying in length from 100 bp to 910 bp. Both genes exhibit typical signal (export) sequences, and in both cases these are interrupted by an additional intron. Each gene also contains an intron between signal peptide and FU-a and in the 3′ untranslated region. Of special relevance for evolutionary considerations are introns interrupting those regions that encode a discrete functional unit. We found that five of the eight FUs in Haliotis each are encoded by a single exon, whereas FU-f, FU-g, and FU-a are encoded by two, three and four exons, respectively. Similarly, in Octopus four of the FUs each correspond to an uninterrupted exon, whereas FU-b, FU-e, and FU-f each contain a single intron. Although the positioning of the introns between FUs is highly conserved in the two mollusks, the introns within FUs show no relationship either in location nor phase. It is proposed that the introns between FUs were generated as the eight-unit polypeptide evolved from a monomeric precursor, and that the internal introns have been added later. A hypothesis for evolution of the ring-like quaternary structure of molluscan hemocyanins is presented.

Vacancy-induced magnetism in graphene and graphene ribbons

We address the electronic structure and magnetic properties of vacancies and voids both in graphene and graphene ribbons. By using a mean-field Hubbard model, we study the appearance of magnetic textures associated with removing a single atom (vacancy) and multiple adjacent atoms (voids) as well as the magnetic interactions between them. A simple set of rules, based on the Lieb theorem, link the atomic structure and the spatial arrangement of the defects to the emerging magnetic order. The total spin S of a given defect depends on its sublattice imbalance, but some defects with S=0 can still have local magnetic moments. The sublattice imbalance also determines whether the defects interact ferromagnetically or antiferromagnetically with one another and the range of these magnetic interactions is studied in some simple cases. We find that in semiconducting armchair ribbons and two-dimensional graphene without global sublattice imbalance, there is a maximum defect density above which local magnetization disappears. Interestingly, the electronic properties of semiconducting graphene ribbons with uncoupled local moments are very similar to those of diluted magnetic semiconductors, presenting giant Zeeman splitting.