Ultrastructure of adhesion and movement of the tetraspores of Gelidium Lamour (Geldiaceae; Rhodophyta)

The outer part of the tetraspora cell wall in Gelidium crinale (Turner) J.V. Lamour. and G. spathulatum (Kutz.) Bornet is morphologically described in relation to the movements and displacement of these spores when they settle on a substratum. We also describe the mechanism of adhesión and the transformations undergone by this mechanism over time. The cell wall shows a network of fibrillar threads embedded in abundant mucilage. The deformations that tetraspores undergo show that the cell wall is relatively elastic

Some techniques on nonlinear analysis and applications

In this paper we present two different results in the context of nonlinear analysis. The first one is essentially a nonlinear technique that, in view of its strong generality, may be useful in different practical problems. The second result, more technical, but also connected to the first one, is an extension of the well-known Pietsch Domination Theorem. The last decade witnessed the birth of different families of Pietsch Domination-type results and some attempts of unification. Our result, that we call "full general Pietsch Domination Theorem" is potentially a definitive Pietsch Domination Theorem which unifies the previous versions and delimits what can be proved in this line.The connections to the recent notion of weighted summability are traced.Comment: 24 page

A general Extraplolation Theorem for absolutely summing operators

In this note we prove a general version of the Extrapolation Theorem, extending the classical linear extrapolation theorem due to B. Maurey. Our result shows, in particular, that the operators involved do not need to be linear

Importance of interlinguistic similarity and stable bilingualism when two languages compete

In order to analyze the dynamics of two languages in competition, one approach is to fit historical data on their numbers of speakers with a mathematical model in which the parameters are interpreted as the similarity between those languages and their relative status. Within this approach, we show here, on the basis of a detailed analysis and extensive calculations, the outcomes that can emerge for given values of these parameters. Contrary to previous results, it is possible that in the long term both languages coexist and survive. This happens only when there is a stable bilingual group, and this is possible only if the competing languages are sufficiently similar, in which case its occurrence is favoured by both similarity and status symmetry.Comment: to appear in New Journal of Physic

Sobre algunas Gelidiáceas nuevas o poco conocidas de las costas españolas

En esta comunicación damos a conocer una nueva localidad de la isla de Tenerife para Gelidiella tinerfensis J. Seoane-Camba, e igualmente se cita Gelidiella tenuissimaJ. Feldmann y G. Hamel en San Vicente de La Barquera (Santander) como nueva localidad para las costas españolas.Se hace un estudio comparativo de Gelidium cartilagineum (L.) Gaillon, procedente de El Cabo, y Gelidium cartilagineum (L.) Gaillon var. canariensis Grunow de Tenerife, llegando a la conclusión de que las posibles afinidades morfológicas e histológicas entre ambos taxa no existen, o son tan lacias como las que pueden existir entre cualesquiera especies de Gelidium. Por ello proponemos el nombre de Gelidium canariensis (Grunow) nov. sp. para la planta canaria.Finalmente se describe una nueva especie de Gelidium, encontrada en la costa cantábrica de la Península Ibérica, con el nombre de Gelidium cantabricum nov. sp.In this paper a new locality of Tenerife Island is made known for Gelidiella tinerfensis J. Seoane-Camba. Likewise, San Vicente de La Barquera (Santander) is made known as a new locality in the spanish shore for Gelidiella tenuissima J. Feldmann y G. Hamel.On the other hand a comparative study between Gelidium cartilagineum (L.) Gaillon, from El Cabo, and Gelidium cartilagineum (L.) Gaillon var. canariensis Grunow, from Tenerife, is made. We conclude that both taxa are different species and we propose the name Gelidium canariensis (Grunow) nov. sp. for the canary plant.Finally we describe a new species of Gelidium, that has been find at Cantabria, with the name Gelidium cantabricum nov. sp