Search results for "RCA"

Cambios de usos del suelo durante la segunda mitad del s. XX en la comarca del Camp del Turia

2015

La inserción laboral de los inmigrantes rumanos y búlgaros en España

2008

Este artículo analiza la incorporación al mercado de trabajo español de los inmigrantes de nacionalidad búlgara y rumana, dos de los colectivos extranjeros que más han crecido en los últimos años. Tras elaborar un breve estado de la cuestión sobre el tema, se analiza su evolución numérica reciente y su distribución geogràfica a nivel de Comunidades Autónomas, sus características sociodemográficas y laborales a partir de la EPA y, finalmente, su inserción laboral por sector de actividad desde la perspectiva de la complementariedad con la población española ocupada en esos mismos sectores. Las conclusiones se centran en subrayar tanto las semejanzas como las diferencias existentes entre ambos…

DNA replication arrest in response to genotoxic stress provokes early activation of stress-activated protein kinases (SAPK/JNK).

2009

Abstract The impact of DNA damage-induced replication blockage for early activation of stress kinases [stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK)] is largely unknown. Here, we show that induction of dual phosphorylation of SAPK/JNK by the DNA polymerase inhibitor aphidicolin was not ameliorated by additional exposure to ultraviolet (UV) light, indicating that overlapping mechanisms participate in signaling to SAPK/JNK triggered by both agents. UV-induced DNA replication blockage, cyclobutane pyrimidine dimer formation and DNA strand break induction coincided with SAPK/JNK phosphorylation at early (≤ 30 min) but not late (≥ 2 h) time points after exposure. Genotoxin…

Almost Planar Homoclinic Loops in R3

1996

AbstractIn this paper we study homoclinic loops of vector fields in 3-dimensional space when the two principal eigenvalues are real of opposite sign, which we call almost planar. We are interested to have a theory for higher codimension bifurcations. Almost planar homoclinic loop bifurcations generically occur in two versions “non-twisted” and “twisted” loops. We consider high codimension homoclinic loop bifurcations under generic conditions. The generic condition forces the existence of a 2-dimensional topological invariant ring (non necessarily unique), which is a topological cylinder in the “non-twisted” case and a topological Möbius band in the “twisted” case. If the third eigenvalue is…

On the number of solutions of a Duffing equation

1991

The exact number of solutions of a Duffing equation with small forcing term and homogeneous Neumann boundary conditions is given. Several bifurcation diagrams are shown.

Bifurcations of links of periodic orbits in non-singular Morse - Smale systems on

1997

The set of periodic orbits of a non-singular Morse - Smale (NMS) flow on defines a link; a characterization of all possible links of NMS flows on has been developed by Wada. In the frame of codimension-one bifurcations, this characterization allows us to study the restrictions a link requires for suffering a given bifurcation. We also derive the topological description of the new link and the possibility of relating links by a chain of this type of bifurcation.

A strain-difference-based nonlocal elasticity model

2004

Abstract A two-component local/nonlocal constitutive model for (macroscopically) inhomogeneous linear elastic materials (but constant internal length) is proposed, in which the stress is the sum of the local stress and a nonlocal-type stress expressed in terms of the strain difference field, hence identically vanishing in the case of uniform strain. Attention is focused upon the particular case of piecewise homogeneous material. The proposed model is thermodynamically consistent with a suitable free energy potential. It constitutes an improved form of the Vermeer and Brinkgreve [A new effective nonlocal strain measure for softening plasticity. In: Chambon, R., Desrues, J., Vardulakis, I. (E…

Tecnhiques for sentiment analysis in Twitter: Supervised Learning and SentiStrength

2017

[EN] Sentiment analysis on Twitter offers possibilities of great interest to evaluate the currents of opinion disseminated through this medium. The huge volumes of texts require tools able to automatically process these messages without losing reliability. This paper describes two different types of approaching this problem. The first strategy is based on Supervised Learning processes, developed in the field of artificial intelligence. Its application requires some tools from natural language processing along with a classifed corpus as a starting point. The second approach is based on polarity dictionaries. SentiStrength tool is located in this line. It is increasingly applied to studies of…

Characterization of Zirconium Phosphate/Polycation Thin Films Grown by Sequential Adsorption Reactions

1997

Monolayer and multilayer thin films consisting of anionic α-zirconium phosphate (α-ZrP) sheets and polycations (poly(allylamine hydrochloride) (PAH), cytochrome c) were characterized by transmission electron microscopy (TEM), ellipsometry, UV−visible absorbance spectroscopy, reflectance FT-IR, XPS, and X-ray diffraction. Titration and powder X-ray diffraction experiments confirm that exfoliation of α-ZrP begins to occur when enough tetra(n-butylammonium) hydroxide (TBA+OH-) has been added to exceed single-layer packing of TBA+ ions (x ≈ 0.50) in the intercalation compound Zr(HPO4)2-x(TBA+PO4-)x·nH2O. The identical contrast of many sheets in TEM micrographs suggests that the suspension is un…

Temporal aspects of copper homeostasis and its crosstalk with hormones

2015

To cope with the dual nature of copper as being essential and toxic for cells, plants temporarily adapt the expression of copper homeostasis components to assure its delivery to cuproproteins while avoiding the interference of potential oxidative damage derived from both copper uptake and photosynthetic reactions during light hours. The circadian clock participates in the temporal organization of coordination of plant nutrition adapting metabolic responses to the daily oscillations. This timely control improves plant fitness and reproduction and holds biotechnological potential to drive increased crop yields. Hormonal pathways, including those of abscisic acid, gibberellins, ethylene, auxin…