Spherically Symmetric Solutions in M\o ller's Tetrad Theory of Gravitation

The general solution of M\o ller's field equations in case of spherical symmetry is derived. The previously obtained solutions are verified as special cases of the general solution.Comment: LaTeX2e with AMS-LaTeX 1.2, 8 page

How Noisy Data Affects Geometric Semantic Genetic Programming

Noise is a consequence of acquiring and pre-processing data from the environment, and shows fluctuations from different sources---e.g., from sensors, signal processing technology or even human error. As a machine learning technique, Genetic Programming (GP) is not immune to this problem, which the field has frequently addressed. Recently, Geometric Semantic Genetic Programming (GSGP), a semantic-aware branch of GP, has shown robustness and high generalization capability. Researchers believe these characteristics may be associated with a lower sensibility to noisy data. However, there is no systematic study on this matter. This paper performs a deep analysis of the GSGP performance over the presence of noise. Using 15 synthetic datasets where noise can be controlled, we added different ratios of noise to the data and compared the results obtained with those of a canonical GP. The results show that, as we increase the percentage of noisy instances, the generalization performance degradation is more pronounced in GSGP than GP. However, in general, GSGP is more robust to noise than GP in the presence of up to 10% of noise, and presents no statistical difference for values higher than that in the test bed.Comment: 8 pages, In proceedings of Genetic and Evolutionary Computation Conference (GECCO 2017), Berlin, German

Sobre la necesidad de un libro rojo «moderno» para China

Los llamados «libros rojos» se cuentan hoy en día entre las mejores y más ampliamente utilizadas herramientas para la identificación de plantas vasculares sometidas a una situación de riesgo, así como para la priorización de los esfuerzos que se deben realizar para su conservación. Los libros rojos constituyen un paso más allá de la elaboración de una «lista roja», puesto que contienen información muy valiosa acerca del estado de conservación de una especie determinada (p. ej. su encuadre taxonómico, sus características biológicas y ecológicas, su área de distribución y sus amenazas actuales y potenciales) aparte de su categoría de amenaza de acuerdo con unos criterios estandarizados. Esta información, a su vez, permitirá aplicar aquellas medidas más adecuadas de cara a su preservación y/o recuperación

A system of degree four with an invariant triangle and at least three small amplitude limit cycles

We show the existence of a polynomial system of degree four having three real invariant straight lines forming a triangle with at least three small amplitude limit cycles in the interior. Also, we obtain the necessary and sufficient conditions for the critical point at the interior of the bounded region to be a center

Flora pteridofítica de la Marina Alta (Alacant)

A partir de material d'herbari i referències bibliogràfiques es revisa i actualitza el catàleg de pteridòfits de la comarca de la Marina Alta (Alacant). Asplenium trichomanes L. subsp. inexpectans Lovis constitueix novetat per a la flora del País Valencià.A partir de material de herbario y de la recopilación de referencias bibliograficas se revisa y actualiza el catálogo de pteridófitos de la Marina Alta (Alicante). Asplenium trichomanes L. subsp. inexpectans Lovis supone novedad para la flora del País Valenciano.On the basis of herbarium material and bibliographic references, we have made a revision of the catalogue of Pteridophyta from Marina Alta (SE Iberian Peninsula). Asplenium trichomanes L. subsp. inexpectans Lovis is recorded for the first time in the Valencian Communit