The mRMR variable selection method: a comparative study for functional data

The use of variable selection methods is particularly appealing in statistical problems with functional data. The obvious general criterion for variable selection is to choose the ‘most representative’ or ‘most relevant’ variables. However, it is also clear that a purely relevance-oriented criterion could lead to select many redundant variables. The minimum Redundance Maximum Relevance (mRMR) procedure, proposed by Ding and Peng (2005) and Peng et al. (2005) is an algorithm to systematically perform variable selection, achieving a reasonable trade-off between relevance and redundancy. In its original form, this procedure is based on the use of the so-calledmutual information criterion to assess relevance and redundancy. Keeping the focus on functional data problems, we propose here a modified version of the mRMR method, obtained by replacing the mutual information by the new association measure (called distance correlation) suggested by Székely et al. (2007). We have also performed an extensive simulation study, including 1600 functional experiments (100 functional models x 4 sample sizes x 4 classifiers) and three real-data examples aimed at comparing the different versions of the mRMR methodology. The results are quite conclusive in favour of the new proposed alternativeThis research has been partially supported by Spanish grant MTM2010- 1736

Arqueología medieval en el Valle de Orduña (Bizkaia) : Origen y evolución del monasterio de San Clemente de Arbileta

El estudio efectuado en San Clemente de Arbileta destaca por el procedimiento metodológico empleado. Una metodología que engloba el estudio integral del conjunto arqueológico y que considera el edificio como un yacimiento arqueológico único donde aplicar las mismas herramientas estratégicas. Todo ello ha permitido obtener uan extensa secuencia histórico-constructiva que, iniciada en época altomedieval, se dilata hasta practicamente nuestros días, constituyendo una nueva e importante aportación al conocimiento de la génesis y evolución del poblamiento en el valle de Orduñ

Evaluación de la justicia ambiental por distritos urbanos como base para las políticas y la intervención públicas

La problemática de las injusticias ambientales demanda diagnósticos por unidades espaciales adecuadas para la formación de decisiones públicas. De acuerdo con ello en esta contribución se pretende: a) abordar el análisis de la exposición potencial de ciertos grupos vulnerables de la población a una polución atmosférica excesiva en Madrid; b) explorar la idoneidad de diversas herramientas analíticas para tal fin; y c) proporcionar bases para el examen de las injusticias ambientales por distritos urbanos, dada su idoneidad para la gobernanza municipal. Metodológicamente se ha procedido a modelar la distribución espacial de dos contaminantes del aire en toda el área urbana, a partir de los datos de las estaciones de medición. Luego se ha medido la exposición de ciertos grupos demográficos vulnerables a alta contaminación y se ha sintetizado los resultados por distritos. Los hallazgos clarifican qué grupos vulnerables y con qué intensidad están más o menos expuestos a alta contaminación y en qué distritos, desvelando así inequidades ambientales y facilitando las deseables intervenciones correctoras.Esta trabajo se ha elaborado dentro del proyecto de investigación “Contaminación atmosférica urbana y justicia ambiental: metodología de evaluación y estudio de casos con sistemas de información geográfica”, financiado por el Ministerio de Economía y Competitividad de España, referencia CSO2011-26177

A Systematic Approach to Subtribe Loliinae (Poaceae: Pooideae) Based on Phylogenetic Evidence

Loliinae (Poaceae, Pooideae) encompass a large group of genera closely related to Festuca, the largest genus in the subtribe, which as traditionally circumscribed has been shown to be highly paraphyletic. In this investigation we combined molecular and morphological data representing 20 genera of Loliinae and closely related subtribes. Combined analysis of nucleotide sequences from the nuclear ITS and chloroplast trnL–F regions and structural characters recovered a consensus topology that shows Loliinae to be monophyletic and possessing two main clades—the fine-leaved Festuca clade that includes Ctenopsis, Micropyrum, Narduroides, Psilurus, Vulpia, and Wangenheimia, and the broad-leaved Festuca clade that includes Lolium and Micropyropsis. The presence of morphologically intermediate, unresolved, or poorly supported taxa (Castellia, Festuca subgen. Subulatae and subgen. Leucopoa p.p., and Festuca sect. Amphigenes p.p.) among the two groups points to a potential evolutionary trend from ancestral broad-leaved taxa to the more recently evolved fine-leaved taxa. Alternate classifications are evaluated for subtribes Loliinae, Cynosurinae, Dactylidinae, and Parapholiinae. We propose to maintain a paraphyletic Festuca as presently circumscribed and not to divide the polyphyletic Vulpia and Festuca infrageneric taxa until more phylogenetic data become available

Numerical simulations of negatively buoyant jets in an immiscible fluid using the Particle Finite Element Method

Negatively buoyant jets consist in a dense fluid injected vertically upward into a lighter ambient fluid. The numerical simulation of this kind of buoyancy‐driven flows is challenging as it involves multiple fluids with different physical properties. In the case of immiscible fluids, it requires, in addition, to track the motion of the interface between fluids and accurately represent the discontinuities of the flow variables. In this paper, we investigate numerically the injection of a negatively buoyant jet into a homogenous immiscible ambient fluid using the Particle Finite Element Method and compare the two‐dimensional numerical results with experiments on the injection of a jet of dyed water through a nozzle in the base of a cylindrical tank containing rapeseed oil. In both simulations and experiments, the fountain inlet flow velocity and nozzle diameter have been varied to cover a wide range of Froude Fr and Reynolds Re numbers ( 0.1 < Fr < 30, 8 < Re < 1350), reproducing both weak and strong laminar fountains. The flow behaviors observed for the different numerical simulations fit in the regime map based on the Re and Fr values of the experiments, and the maximum fountain height is in good agreement with the experimental observations, suggesting that particle finite element method is a useful tool for the study of immiscible two‐fluid systems

Caracterización de la calidad del aire en la ciudad de Valencia: Un análisis basado en la interpolación espacial de contaminantes

Puesto que el aire es un recurso vital y que su degradación puede ocasionar daños a la salud y al medioambiente, evaluar la contaminación atmosférica de las ciudades se ha convertido en una prioridad según la Organización Mundial de la Salud (OMS). El objetivo de este trabajo ha sido determinar la calidad del aire en la ciudad de Valencia, estimando los patrones espaciales de dióxido de nitrógeno (NO2) y de partículas en suspensión (PM10) y determinando qué zonas de la ciudad superan los límites legales nacionales e internacionales. Para ello se han realizado tratamientos de interpolación y visualización mediante el programa ArcGIS. Este trabajo representa un primer paso en la necesaria producción de más investigaciones sobre justicia ambiental en Europa, particularmente en España

Functional diffusion maps

Nowadays many real-world datasets can be considered as functional, in the sense that the processes which generate them are continuous. A fundamental property of this type of data is that in theory they belong to an infinite-dimensional space. Although in practice we usually receive finite observations, they are still high-dimensional and hence dimensionality reduction methods are crucial. In this vein, the main state-of-the-art method for functional data analysis is Functional PCA. Nevertheless, this classic technique assumes that the data lie in a linear manifold, and hence it could have problems when this hypothesis is not fulfilled. In this research, attention has been placed on a non-linear manifold learning method: Diffusion Maps. The article explains how to extend this multivariate method to functional data and compares its behavior against Functional PCA over different simulated and real example

Early-stage macroporosity enhancement in calcium phosphate cements by inclusion of poly(N-vinylpyrrolidone) particles as a porogen

The incorporation of poly(DL-lactic-co-glycolic acid) (PLGA) particles into calcium phosphate cements (CPCs) is an effective strategy to enhance CPC macroporosity and degradation. However, bone regeneration is hindered until hydrolytic PLGA degradation starts a few weeks after implantation. Additionally, CPC and CPC/PLGA injectability and cohesion are suboptimal. In the current study, poly(N-vinylpyrrolidone) (PVP), a water-soluble polymer, was incorporated as a porogen in CPC and CPC/PLGA composites to enhance handling properties and early-stage macroporosity formation. Further, the effect of PVP molecular weight (Mw) and particle size was studied. The results showed that PVP incorporation increased both injectability and cohesion of the CPC pastes, especially with addition of high Mw PVP. Moreover, the in vitro degradation studies revealed that incorporation of PVP induced an initial mass loss during the first week of incubation. In combination with PLGA, small PVP particles induced a higher mass loss at an early stage than large PVP particles, but this effect was no longer apparent after 4 weeks of incubation. In contrast, the incorporation of low Mw PVP had a stronger effect on in vitro degradation in the long term compared to high Mw. Finally, the presence of PLGA porogens appeared to be necessary for adequate CPC degradation.Peer ReviewedPostprint (published version

El yacimiento arqueológico de El Saucedo (Talavera La Nueva, Toledo): balance y perspectivas

En este artículo presentamos una síntesis de los trabajos de investigación, conservación y difusión reali-zados en el yacimiento de b'l Saucedo hasta el presente, así como un esbozo de los planes de actuación para el futuro