Equivalence of the ellipticity conditions for geometric variational problems

We exploit the so called atomic condition, recently defined by De Philippis, De Rosa, and Ghiraldin in [Comm. Pure Appl. Math.] and proved to be necessary and sufficient for the validity of the anisotropic counterpart of the Allard rectifiability theorem. In particular, we address an open question of this seminal work, showing that the atomic condition implies the strict Almgren geometric ellipticity condition

One numerical procedure for two risk factors modeling

We propose a numerical procedure for the pricing of financial contracts whose contingent claims are exposed to two sources of risk: the stock price and the short interest rate. More precisely, in our pricing framework we assume that the stock price dynamics is described by the Cox, Ross Rubinstein (CRR, 1979) binomial model under a stochastic risk free rate, whose dynamics evolves over time accordingly to the Black, Derman and Toy (BDT, 1990) one-factor model. To this aim, we set the hypothesis that the instantaneous correlation between the trajectories of the future stock price (conditional on the current value of the short rate) and of the future short rate is zero. We then apply the resulting stock price dynamics to evaluate the price of a simple contract, i.e. of a stock option. Finally, we compare the derived price to the price of the same option under different pricing models, as the traditional Black and Scholes (1973) model. We expect that, the difference in the two prices is not sensibly large. We conclude showing in which cases it should be helpful to adopt the described model for pricing purposes.option pricing; stochastic short rate model; binomial tree

Space, mass and ornament in the Gothic-Renaissance transition in Spain

La introducción en España de las nuevas formas y sintaxis renacentistas a lo largo del siglo xvi no se produjo con un abandono radical e inmediato de los viejos usos góticos, de validez comprobada en trascendentales cuestiones del diseño arquitectónico. La renovación de la producción fue heterogénea y en cierto modo particular de cada artífice, según su formación previa y el grado de contacto, coherencia y compromiso con las novedades italianas, generando un panorama híbrido y plural en la arquitectura del quinientos hispano. Atendiendo a significativos textos y documentos gráficos de la época, se pretende rastrear los cambios, e inercias, en el proceso de diseño arquitectónico durante esta larga etapa de transición, estructurando el análisis a partir de tres categorías sustanciales, interdependientes y autónomas a la vez: espacio, masa y ornato.During the sixteenth century the new Renaissance forms were introduced in Spain, but the Gothic procedures continued to be used due to their proven validity for the architectural design. The renovation of the architecture was heterogeneous and different for each master, according to his previous training and his knowledge of the new Italian forms. This involved a hybrid and plural context in the Spanish architecture of the 16th century. The changes and continuities of the architectural design process during this transitory stage are investigated in this paper, based on significant texts and graphic documents of this period. The analysis is structured based on three substantial architectural categories, which are simultaneously interdependent and autonomous: space, mass and ornamen

On the lower semicontinuous envelope of functionals defined on polyhedral chains

In this note we prove an explicit formula for the lower semicontinuous envelope of some functionals defined on real polyhedral chains. More precisely, denoting by $H \colon \mathbb{R} \to \left[ 0,\infty \right)$ an even, subadditive, and lower semicontinuous function with $H(0)=0$, and by $\Phi_H$ the functional induced by $H$ on polyhedral $m$-chains, namely \Phi_{H}(P) := \sum_{i=1}^{N} H(\theta_{i}) \mathcal{H}^{m}(\sigma_{i}), \quad\mbox{for every }P=\sum_{i=1}^{N} \theta_{i} [[ \sigma_{i} ]] \in\mathbf{P}_m(\mathbb{R}^n), we prove that the lower semicontinuous envelope of $\Phi_H$ coincides on rectifiable $m$-currents with the $H$-mass \mathbb{M}_{H}(R) := \int_E H(\theta(x)) \, d\mathcal{H}^m(x) \quad \mbox{ for every } R= [[ E,\tau,\theta ]] \in \mathbf{R}_{m}(\mathbb{R}^{n}). Comment: 14 page

Estimation of the methane emission factor for the Italian Mediterranean buffalo

In order to contribute to the improvement of the national greenhouse gas emission inventory, this work aimed at estimating a country-specific enteric methane (CH4) emission factor for the Italian Mediterranean buffalo. For this purpose, national agriculture statistics, and information on animal production and farming conditions were analysed, and the emission factor was estimated using the Tier 2 model of the Intergovernmental Panel on Climate Change. Country-specific CH4 emission factors for buffalo cows (630 kg body weight, BW) and other buffalo (313 kg BW) categories were estimated for the period 1990–2004. In 2004, the estimated enteric CH4 emission factor for the buffalo cows was 73 kg/head per year, whereas that for other buffalo categories it was 56 kg/head per year. Research in order to determine specific CH4 conversion rates at the predominant production system is suggested

Algunos datos de la historia académica de nuestros maestros en el ámbito de la enseñanza y aprendizaje de las ciencias

El trabajo forma parte de una tesis doctoral cuya finalidad es identificar y analizar las características de los maestros en su periodo de formación inicial. En este estudio nos centramos sólo en algunos datos de la educación formal y no formal que creemos relevantes de cara a la planificación de una propuesta de formación que tenga en cuenta los destinatarios de la misma. Se ha recogido la información de más de cien estudiantes de Maestro en la Universidad de Murcia, mediante un cuestionario de elaboración propia. Los resultados ponen de manifiesto una gran distancia entre el modelo de enseñanza que queremos compartir con ellos y el que tuvieron