Authors:A. Rodríguez, R. Hernández, R. Ma. García, and L. Macías
The decomposition of AU, UO3, and U3O8 has been studied at different heating rates and calcining temperatures at atmospheric pressure with pure carbon monoxide, in the temperature range of 350 to 1000°C. X-ray powder patterns and infrared analysis of samples revealed that the final products depend upon the nature of the precursor and its thermal treatment.
Authors:J. A. García, Rosa Rodriguez-Sánchez, and J. Fdez-Valdivia
Here we show a comparison of top economics departments in the US and EU based on a summary measure of the multidimensional prestige of influential papers in 2010. The multidimensional prestige takes into account that several indicators should be used for a distinct analysis of structural changes at the score distribution of paper prestige. We argue that the prestige of influential articles should not only consider one indicator as a single dimension, but in addition take into account further dimensions, since several different indicators have been developed to evaluate the impact of academic papers. After having identified the multidimensionally influential articles from an economics department, their prestige scores can be aggregated to produce a summary measure of the multidimensional prestige of research output of this department, which satisfies numerous properties.
Authors:J. A. García, Rosa Rodriguez-Sánchez, and J. Fdez-Valdivia
Here we show a longitudinal analysis of the overall prestige of first quartile journals during the period between 1999 and 2009, on the subject areas of Scopus. This longitudinal study allows us to analyse developmental trends over times in different subject areas with distinct citation and publication patterns. To this aim, we first introduce an axiomatic index of the overall prestige of journals with ranking score above a given threshold. Here we demonstrate that, between 1999 and 2009, there was high and increasing overall prestige of first quartile journals in only four areas of Scopus. Also, there was high and decreasing overall prestige of first quartile journals in five areas. Two subject areas showed high and oscillating overall prestige of first quartile journals. And there was low and increasing overall prestige in four areas, since the 1999.
Authors:L. E. Garcia-Megias, E. Colacio-Rodriguez, A. Garcia-Rodriguez, J. Ruiz-Sanchez, and J. M. Salas-Peregrin
The thermal behaviour of 6-amino-5-formyluracil (HFU), 6-amino-1-methyl-5-formyluracil (1-MFU), 6-amino-3-methyl-5-formyluracil (3-HFU) and 6-amino-1,3-dimethyl-5-formyluracil (HDFU) is described. Only HDFU is shown to contain crystallization water. Dehydration and fusion enthalpy values have been calculated from the DSC curves. Likewise, the thermal behaviour of new complexes obtained by reaction between the above pyrimidine derivatives and Ni(II), Cu(II) and Pd(II) ions is reported.
Authors:L. Desdín García, G. Capote Rodríguez, A. Leyva Fabelo, and L. Calderín Hidalgo
This paper shows the influence of hardness on the beta backscattering coefficient from heat treated and plastic deformed carbon
steel specimens. The observed effect cannot be explained as a change in the chemical composition of the sample (or effective
atomic number). In order to explain the observed dependencies, it is necessary to take into account the structural defect
and morphological changes of the different phases.
Authors:J. A. García, Rosa Rodriguez-Sánchez, J. Fdez-Valdivia, and J. Martinez-Baena
Here we study the relationship between journal quartile rankings of ISI impact factor (at the 2010) and journal classification in four impact classes, i.e., highest impact, medium highest impact, medium lowest impact, and lowest impact journals in subject category computer science artificial intelligence. To this aim, we use fuzzy maximum likelihood estimation clustering in order to identify groups of journals sharing similar characteristics in a multivariate indicator space. The seven variables used in this analysis are: (1) Scimago Journal Ranking (SJR); (2) H-Index (H); (3) ISI impact factor (IF); (4) 5-Year Impact Factor (5IF); (5) Immediacy Index (II); (6) Eigenfactor Score (ES); and (7) Article Influence Score (AIS). The fuzzy clustering allows impact classes to overlap, thereby accommodating for uncertainty related to the confusion about the impact class attribution for a journal and vagueness in impact classes definition. This paper demonstrates the complex relationship between quartiles of ISI impact factor and journal impact classes in the multivariate indicator space. And that several indicators should be used for a distinct analysis of structural changes at the score distribution of journals in a subject category. Here we propose it can be performed in a multivariate indicator space using a fuzzy classifier.
Authors:J. Madrigal-González, J. García-Rodríguez, A. Puerto-Martín, B. Fernández-Santos, and P. Alonso-Rojo
In arid and semi-arid ecosystems, the presence of woody neighbours affects the existence of several herbaceous species by modifying critical aspects of the environment (e.g., soil humidity, nutrient content or light availability) beneath their canopies. Herbaceous species growing in the understory of
may be distinct from those in open areas due to litter fall, light interception and changes in nutrient availability. We suggest that the overall effect of woody neighbours on herbaceous layer diversity may vary with the scale focus of analysis. To examine this hypothesis, we collected data on the abundance of herbaceous species in open pineland forests of the central Iberian Peninsula (Spain) using sample quadrats of 0.5 m × 0.5 m distributed beneath, at the edge, and outside the canopy of pines in a landscape composed of dunes and plains. The results of CCA ordination revealed significant spatial segregation of herbaceous species reflecting the occurrence of pines and dunes in the landscape. Nested ANOVA disclosed markedly lower species richness beneath the pines, particularly in the dune sites. Species richness partitioning showed higher pine-induced heterogeneity than expected from the sample-based randomized model, leading to significantly increased species richness at the patch level. Hence, the outcome of pine-induced effects on the herbaceous plant diversity is scale-dependent, negative if we focus on separate communities, but positive if the scale focus is extended to whole patches comprising the sum of communities beneath, at the edge, and outside pine tree canopies. These results emphasize the necessity of using various scale perspectives to clarify the different ways in which pines and other woody nurse species affect structure of herbaceous communities in semi-arid Mediterranean ecosystems.
Authors:J. A. García, Rosa Rodriguez-Sánchez, J. Fdez-Valdivia, Daniel Torres-Salinas, and Francisco Herrera
A university may be considered as having dimension-specific prestige in a scientific field (e.g., physics) when a particular bibliometric research performance indicator exceeds a threshold value. But a university has multidimensional prestige in a field of study only if it is influential with respect to a number of dimensions. The multidimensional prestige of influential fields at a given university takes into account that several prestige indicators should be used for a distinct analysis of the influence of a university in a particular field of study. After having identified the multidimensionally influential fields of study at a university their prestige scores can be aggregated to produce a summary measure of the multidimensional prestige of influential fields at this university, which satisfies numerous properties. Here we use this summary measure of multidimensional prestige to assess the comparative performance of Spanish Universities during the period 2006–2010.
Authors:L. Núñez-Regueira, J. Rodríguez-Añón, J. Proupín-Castiñeiras, and A. Romero-García
Calorific values and flammability changes during a year for forest waste originating from silviculture task in Galicia (NW
Spain) are reported. These waste materials are becoming to be used as alternative fuels.
The present study was made on several hardwood forest species. These forest species occupy nowadays approximately 30% of the
total forest surface of Galicia.
Calorific values were measured by static bomb calorimeter in an oxygen atmosphere. Flammability was determined using a standard
epiradiator. Simultaneously, some other parameters such as elementary chemical composition, heavy metal contents, moisture,
density, ash percentage after combustion in the bomb, and main bioclimatic characteristics, were also determined.
Authors:J. González-Irún Rodríguez, P. Carreira, A. García-Diez, D. Hui, R. Artiaga, and L. Liz-Marzán
The effect of silica
nanofiller on the glass transition of a polyurethane was studied by DSC. The
pristine polymer exhibits a single glass transition at about –10C.
Uniform SiO2 spheres with different average sizes and narrow size distributions
were synthesized in solution by the Stber method . Both the effects
of silica content within the polymer and particle size were investigated,
as well as two different surface treatments. Scanning electron microscopy
(SEM) clearly confirms the presence of the particles within the polymer matrix,
showing uniform distribution and no agglomeration. While shifting of the glass
transition has been reported by many authors, we have not seen any noticeable
shift in this polymer. Surprisingly, we found no relevant effects when either
increasing the filler content or changing the particle size. Different amounts
of particles with average diameters of 175, 395 and 730 nm did not affect
the glass transition temperature of the pristine polymer.