Localisation and finite-size effects in graphene flakes

We show that electron states in disordered graphene, with an onsite potential that induces inter-valley scattering, are localised for all energies at disorder as small as of the band width of clean graphene. We clarify that, in order for this Anderson-type localisation to be manifested, graphene flakes of size or larger are needed. For smaller samples, due to the surprisingly large extent of the electronic wave functions, a regime of apparently extended (or even critical) states is identified. Our results complement earlier studies of macroscopically large samples and can explain the divergence of results for finite-size graphene flakes

Iron Metabolism in Obesity and Metabolic Syndrome

Obesity is an excessive adipose tissue accumulation that may have detrimental effects on health. Particularly, childhood obesity has become one of the main public health problems in the 21st century, since its prevalence has widely increased in recent years. Childhood obesity is intimately related to the development of several comorbidities such as nonalcoholic fatty liver disease, dyslipidemia, type 2 diabetes mellitus, non-congenital cardiovascular disease, chronic inflammation and anemia, among others. Within this tangled interplay between these comorbidities and associated pathological conditions, obesity has been closely linked to important perturbations in iron metabolism. Iron is the second most abundant metal on Earth, but its bioavailability is hampered by its ability to form highly insoluble oxides, with iron deficiency being the most common nutritional disorder. Although every living organism requires iron, it may also cause toxic oxygen damage by generating oxygen free radicals through the Fenton reaction. Thus, iron homeostasis and metabolism must be tightly regulated in humans at every level (i.e., absorption, storage, transport, recycling). Dysregulation of any step involved in iron metabolism may lead to iron deficiencies and, eventually, to the anemic state related to obesity. In this review article, we summarize the existent evidence on the role of the most recently described components of iron metabolism and their alterations in obesity

Characterization of ten white matter tracts in a representative sample of Cuban population

Background: The diffusion tensor imaging technique (DTI) combined with tractography methods, has achieved the tridimensional reconstruction of white matter tracts in the brain. It allows their characterization in vivo in a non-invasive way. However, one of the largest sources of variability originates from the location of regions of interest, is therefore necessary schemes which make it possible to establish a protocol to be insensitive to variations in drawing thereof. The purpose of this paper is to stablish a reliable protocol to reconstruct ten prominent tracts of white matter and characterize them according to volume, fractional anisotropy and mean diffusivity. Also we explored the relationship among these factors with gender and hemispheric symmetry. Methods: This study aims to characterize ten prominent tracts of white matter in a representative sample of Cuban population using this technique, including 84 healthy subjects. Diffusion tensors and subsequently fractional anisotropy and mean diffusivity maps were calculated from each subject's DTI scans. The trajectory of ten brain tracts was estimated by using deterministic tractography methods of fiber tracking. In such tracts, the volume, the FA and MD were calculated, creating a reference for their study in the Cuban population. The interactions between these variables with age, cerebral hemispheres and gender factors were explored using Repeated Measure Analysis of Variance. Results: The volume values showed that a most part of tracts have bigger volume in left hemisphere. Also, the data showed bigger values of MD for males than females in all the tracts, an inverse behavior than FA values. Conclusions: This work showed that is possible reconstruct white matter tracts using a unique region of interest scheme defined from standard to native space. Also, this study indicates differing developmental trajectories in white matter for males and females and the importance of taking gender into account in developmental DTI studies and in underlie gender-related cognitive differences

Consideraciones sobre la dinámica geomorfológica actual de laderas semiáridas de la Depresión del Ebro: el caso de la Val de las Lenas (término municipal de María de Huerva, Zaragoza, España)

[Resumen] En este trabajo se realiza una aproximación al funcionamiento geomorfológico actual de las vales del semiárido aragonés. Las investigaciones contemplan sucesivas aproximaciones, en las que se analizarán: (1) la evolución de humedad en el suelo en diferentes profundidades y posiciones de ladera, (2) las variaciones de la textura del depósito y (3) la simulación de lluvia. Los resultados indican la posible existencia de un funcionamiento hidrológico dislocado a lo largo de la ladera entre el talud superior y los niveles basales. A lo largo del relleno, además, la franja superior parece depender hidrológicamente de su proximidad al talud rocoso adyacente (funcionamiento alóctono), mientras que el depósito de val parece comportarse hidrológicmente de manera autóctona. Entre las partes altas y bajas del relleno de val se aprecia una inversión de las condiciones hídricas que definen su potencial biológico, cuyo reparto espacial es inverso al esperado.[Abstract] We have studied the geomorphological behaviour of slope in a semiarid landscape (NE inland Spain). The approach have been done by the analysis of soil water evolution, particle size analysis and rainfall simulation from top to bottom of slope. Results suggest the posibility of hidrological compartimentation between upper free face and talus; talus is not homogeneous, and there exist a strip in the contact zone with upper free face which change the hidrological regime from upper to lower part of talus

Instrumentos y trabajos geodésicos de la Armada: la Comisión Hidrográfica de la Península y el Observatorio de San Femando (1859-1887)

This article introduces a brief survey on the geodetic tasks carried out by the Spanish Navy in the 19th century, and the scientific instruments used by the San Fernando Observatory and the hydrographical expeditions. Special attention deserves the Iberian Peninsula Hydrographical Expedition, in charge of surveying the Spanish coasts.Este artículo presenta un breve estudio sobre los trabajos geodésicos emprendidos por la Armada Española en el siglo XIX, y los instrumentos utilizados por el Observatorio de San Fernando y por las comisiones hidrográficas, especialmente la Comisión Hidrográfica de la Península, encargada del levantamiento cartográfico de las costas españolas

A Model-Driven Approach for Business Process Management

The Business Process Management is a common mechanism recommended by a high number of standards for the management of companies and organizations. In software companies this practice is every day more accepted and companies have to assume it, if they want to be competitive. However, the effective definition of these processes and mainly their maintenance and execution are not always easy tasks. This paper presents an approach based on the Model-Driven paradigm for Business Process Management in software companies. This solution offers a suitable mechanism that was implemented successfully in different companies with a tool case named NDTQ-Framework.Ministerio de Educación y Ciencia TIN2010-20057-C03-02Junta de Andalucía TIC-578

Shape and kinematics of elliptical galaxies: evolution due to merging at z < 1.5

[EN]Aims. We investigate the evolution in the shape and kinematics of elliptical galaxies in a cosmological framework. Methods. We identified relaxed, elliptical-like objects (ELOs) at redshifts z = 0, z = 0.5, z = 1 and z = 1.5 within a set of hydrodynamic, self-consistent simulations completed for a concordance cosmological model. Results. The population of elliptical systems that we analysed evolve systematically with time becoming rounder in general by z = 0 and also more velocity dispersion supported. We found that this is due primarily to major dry mergers where only a modest amount of angular momentum is involved in the merger event. Despite the general trend, in a significant number of cases the merger event involves a relatively high amount of specific angular momentum, which causes the system in general to acquire higher rotational support and/or a more oblate shape. These evolutionary patterns persist when we study our systems in projection, in simulating true observations, and thus should be evident in future observations.Peer reviewe