Quadratic Maps in Two Variables on Arbitrary Fields

Let $\mathbb{F}$ be a field of characteristic different from $2$ and $3$, and let $V$ be a vector space of dimension $2$ over $\mathbb{F}$. The generic classification of homogeneous quadratic maps $f\colon V\to V$ under the action of the linear group of $V$, is given and efficient computational criteria to recognize equivalence are provided.Comment: 12 pages, no figure

Disponibilidad léxica sobre palabras específicas en estudiantes de Educación Secundaria de Almería

Resumen basado en el de la publicaciónTítulo, resumen y palabras clave también en inglésSiguiendo la tradición previa de investigación sobre didáctica de la lengua y disponibilidad léxica, se presentan los resultados de la aplicación de una prueba asociativa a una muestra de cuatrocientos estudiantes de Educación Secundaria, durante el curso académico 1998-1999, en la ciudad de Almería (España). El objetivo del trabajo consistió en determinar los usos específicos de palabras basadas en dieciocho centros de interés. Es decir, se examinaron palabras de registro coloquial, extranjerismos, formas dialecto-patrimoniales, marcas, siglas y abreviaturas. Finalmente, se proporciona un análisis de estos grupos léxico-semánticos, desde una perspectiva descriptiva, que permite conocer mejor el vocabulario específico con el que cuentan los discentes en este nivel de enseñanza.ES

Isoscaling and the high Temperature limit

This study shows that isoscaling, usually studied in nuclear reactions, is a phenomenon common to all cases of fair sampling. Exact expressions for the yield ratio $R_{21}$ and approximate expressions for the isoscaling parameters $\alpha$ and $\beta$ are obtained and compared to experimental results. It is concluded that nuclear isoscaling is bound to contain a component due to sampling and, thus, a words of caution is issued to those interested in extracting information about the nuclear equation of state from isoscaling.Comment: 7 pages, 1 figur

Climate-driven changes in life-history traits of the bastard grunt (Pomadasys incisus) in the north-western Mediterranean

This study evaluates the influence of sea water temperature on the life-history traits of the thermophilic bastard grunt Pomadasys incisus in the Catalan coast. We compared two key traits of this species, condition and reproduction, from populations in two separate areas with different thermal regimes: the Gulf of Roses (cold area) and the Ebre Delta (warm area). Specimens were collected monthly from each area between 2010 and 2012. The results were also compared with those given in the literature from sites where the species is more common, i.e. the southern Mediterranean and eastern Atlantic. Our findings indicate that, compared to the populations in warmer environments, the population inhabiting the colder waters appears to be in significantly poorer condition and there is some deviance in their life-history traits: egg size and quality being traded-off for higher egg numbers; lower lengths at maturity and alterations to spawning phenology. A certain degree of plasticity in life-history traits may favour the process of expansion and establishment of this thermophilic species into newly available but colder habitats of the north-western Mediterranean under a scenario of climate change

Cryptanalysis of a novel cryptosystem based on chaotic oscillators and feedback inversion

An analysis of a recently proposed cryptosystem based on chaotic oscillators and feedback inversion is presented. It is shown how the cryptosystem can be broken when Duffing's oscillator is considered. Some implementation problems of the system are also discussed.Comment: 9 pages, 3 figures, latex forma

Foeniculum sanguineum Triano y A. Pujadas (Apiaceae) nueva especie del suroeste de la Región Mediterránea

Foeniculum sanguineum Triano & A. Pujadas, sp. nov., from the south western Mediterranean Region (Spain & Morocco) is described. Its characterization and a comparative study with the related species Foeniculum vulgare Mill., has been carried out through morphological, cytological, chemical and molecular analysis. F. sanguineum is distinguished primarily for its red petals, pink pollen in fresh, and red stylopod. It is a diploid species (2n= 22). A high proportion of limonene and piperitenone oxide (absent in F. vulgare) has been found in the essential oil composition of the dry fruits of F. sanguineum and a high amount (about 50 %) of α-phellandrene in its roots and stems. Phylogenetic analyses were performed using the internal transcribed spacer sequences of nuclear ribosomal DNA (ITS) and the chloroplast rbcL gene sequences. ITS analysis supports the existence of the new species, while revealing sequence divergence both at the intraspecific and at the interspecific levels. A Single-nucleotide-polymorphism (SNP) sequence divergence found in the slow evolving chloroplast gene provided additional support for the novel species characterization, for which the name Foeniculum sanguineum is proposed