Datos sobre la vegetación de la zona de "El Trocadero" (Cádiz)

Sin resume

Phytoplankton composition in a neritic area of the Balearic Sea (Western Mediterranean)

From September 2000 to September 2001 the concentration of chlorophyll a, and the abundance and composition of the phytoplanktonic community was studied in a neritic station of the Mallorca Channel (Western Mediterranean). Sampling was performed approximately every 12 days. Chlorophyll a concentration and phytoplankton abundance reached maxima of 1.79 mg L2l and 352 cells mL21, respectively. It was a relatively productive period, as a result of the high convective mixing in winter and the prevalence of northern waters during most of the cycle. Phytoplankton proliferations (chlorophyll-a concentration .1 mg L21) were detected in January, February, March and June. Those blooms mainly happened under the influence of northern waters, with the exception of the February proliferation, when mixing conditions were found. During bloom conditions it highlights the presence of coccolithophores as proliferation precursors. During no-bloom situations the phytoplankton community was mainly constituted by nanoplanktonic flagellated forms. The Winter Mixing period was dominated by different groups of nanoflagellates, including coccolithophores, undetermined flagellates and dinoflagellates. However, in the most oligotrophic conditions (from April until November) dinoflagellates were clearly dominant, except in the DCM in summer where diatoms prevailed.Versión del edito

Factors limiting ferroelectric field-effect doping in complex oxide heterostructures

Ferroelectric field-effect doping has emerged as a powerful approach to manipulate the ground state of correlated oxides, opening the door to a different class of field-effect devices. However, this potential is not fully exploited so far, since the size of the field-effect doping is generally much smaller than expected. Here we study the limiting factors through magnetotransport and scanning transmission electron and piezoresponse force microscopy in ferroelectric/superconductor (YBa₂Cu₃O_(7-δ)/BiFeO₃) heterostructures, a model system showing very strong field effects. Still, we find that they are limited in the first place by an incomplete ferroelectric switching. This can be explained by the existence of a preferential polarization direction set by the atomic terminations at the interface. More importantly, we also find that the field-effect carrier doping is accompanied by a strong modulation of the carrier mobility. Besides making quantification of field effects via Hall measurements not straightforward, this finding suggests that ferroelectric poling produces structural changes (e.g., charged defects or structural distortions) in the correlated oxide channel. Those findings have important consequences for the understanding of ferroelectric field effects and for the strategies to further enhance them

Interface barriers for flux motion in high-temperature superconducting superlattices

We study angular dependent magnetoresistance in the vortex-liquid phase of epitaxial YBa2Cu3O7 thin films and YBa_2Cu_3O_7/PrBa_2Cu_3O_7 superlattices. Superlattices were grown with different PrBa_2Cu_3O_7 thickness in order to tune coupling between YBa_2Cu_3O_7 layers. While dissipation of single film and coupled superlattices is scaled with the anisotropic three-dimensional model in the whole angular range, decoupling through PrBa_2Cu_3O_7 spacer breaks down the scaling and yields strong reduction of the dissipation when the magnetic fields are applied up to ±20degrees around the interface direction. Bean-Livingston barriers at the interface are the mechanism which governs this behavior

A patchy particle model for C-S-H formation

The composition and structure of Calcium-Silicate-Hydrate (C-S-H) phases depends on various reaction parameters leading to its formation. Molecular Dynamic simulation studies probing the formation and structure of C-S-H are generally computationally expensive and can reach only very short time scales. Herein, we propose a coarse graining approach to model the formation of C-S-H, using patchy particles and a modified Patchy Brownian Cluster Dynamics algorithm. The simulations show that patchy particle systems can recover the qualitative kinetic evolution of C-S-H formation, and the obtained final structures were comparable to previously reported molecular dynamics studies and experiments. The model was extended to study the effect of water in the polymerization of tetraethoxysilane oligomers, the principal component of an impregnation treatment for deteriorated concrete surfaces. The intermediate system properties predicted by the simulations, such as viscosity and gel time, and structure were found to be well in accordance with the tailored experiments.The work described in this manuscript has been performed under InnovaConcrete EC project, supported by funding from the European Union's Horizon 2020 Research and Innovation Programme under Grant Agreement N◦760858. AP and JSD also acknowledge the support received from the BASKRETE initiative and the Joint Transborder Lab-oratory (LTC) “Aquitaine-Euskadi Network in Green Concrete and Cement-based Material

Analyzing navigation logs in MOOC: A case study

Continued use of various technological devices has massively increased the generation of digital data, which are recorded as an opportunity for research. In the educational case, it is common to analyze data generated in Learning Management Systems which allows better understand the learning process of the participants and make informed decisions for better e-learning processes and situations in which develop. This paper analyzes participants’ navigation logs in a MOOC hosted on the Coursera platform, for which a visual e-learning analytics process was performed. The results confirm that the videos of experts are an essential educational resource for learning in a MOOC, similarly, the discussion forums are an important resource which are recurrent social spaces in different navigation paths complementing other activities

The best skies for astronomy

Seminario impartido por Casiana Muñoz-Tuñón (IAC) el 15 de noviembre de 2016 en las Oficinas del CIAI en Santa Cruz de Tenerife

Ghrelin and lipid metabolism: key partners in energy balance

Disclaimer: this is not the definitive version of record of this article. This manuscript has been accepted for publication in "Journal of Molecular Endocrinology", but the version presented here has not yet been copy-edited, formatted or proofed. Consequently, Bioscientifica acepts no responsability for any errors on omissions it may contain. The definitive version is now freely avaliable at doi 10.1677/JME-10-0068[Abstract] Ghrelin, the endogenous ligand of the GH secretagogue receptor, has a pleiotropic role in the modulation of energy balance. Recent evidence has demonstrated that besides its orexigenic role, ghrelin regulates central and peripheral lipid metabolism through specific control of hypothalamic AMP-activated protein kinase (AMPK), a critical metabolic gauge regulating both cellular and whole-body energy homeostasis. In this review, we summarize the new milestones of ghrelin's actions on energy balance, with particular focus on its molecular interaction with hypothalamic AMPK and fatty acid metabolism. Understanding this new metabolic pathway can provide new therapeutic targets for the treatment of obesity and the metabolic syndrome.European Commission; FP7/2007–2013 no. 245009European Commission; FP7/2007–2013; nº 018734Xunta de Gailcia; PS07/12Xunta de Gailcia; PGIDIT06PXIB208063PRXunta de Gailcia; 10PXIB208164PRInstituto de Salud Carlos III; PI051024Instituto de Salud Carlos III;PI070413Instituto de Salud Carlos III; PS09/01880Ministerio de Educacion y Ciencia; RyC-2008-02219Ministerio de Educacion y Ciencia; BFU2008Ministerio de Educacion y Ciencia; RyC-2007-0021