The Vector Curvaton

We analyze a massive vector field with a non-canonical kinetic term in the action, minimally coupled to gravity, where the mass and kinetic function of the vector field vary as functions of time during inflation. The vector field is introduced following the same idea of a scalar curvaton, which must not affect the inflationary dynamics since its energy density during inflation is negligible compared to the total energy density in the Universe. Using this hypothesis, the vector curvaton will be solely responsible for generating the primordial curvature perturbation \zeta. We have found that the spectra of the vector field perturbations are scale-invariant in superhorizon scales due to the suitable choice of the time dependence of the kinetic function and the effective mass during inflation. The preferred direction, generated by the vector field, makes the spectrum of \zeta depend on the wavevector, i.e. there exists statistical anisotropy in \zeta. This is discussed principally in the case where the mass of the vector field increases with time during inflation, where it is possible to find a heavy field (M >> H) at the end of inflation, making the particle production be practically isotropic; thus, the longitudinal and transverse spectra are nearly the same order which in turn causes that the statistical anisotropy generated by the vector field is within the observational bounds.Comment: LaTex file in Aipproc style, 6 pages, no figures. Prepared for the conference proceedings of the IX Mexican School of the DGFM-SMF: Cosmology for the XXIst Century. This work is entirely based on Refs. [23-26] and is the result of Andres A. Navarro's MSc thesi

Regional Policy and Convergence in Europe: The Case of Backward Regions

This paper analyzes the performance of regions whose development is lagging behind since the institutionalization of the EU regional policy, (1989). Results from a panel data model with fixed effects prove that backward regions have been catching up with the EU average income since the launching of the first programming period, the so called Delors'I package, 1989-1993

Non-Abelian SS-term dark energy and inflation

We study the role that a cosmic triad in the generalized $SU(2)$ Proca theory, specifically in one of the pieces of the Lagrangian that involves the symmetric version $S_{\mu \nu}$ of the gauge field strength tensor $F_{\mu \nu}$, has on dark energy and primordial inflation. Regarding dark energy, the triad behaves asymptotically as a couple of radiation perfect fluids whose energy densities are negative for the $S$ term but positive for the Yang-Mills term. This leads to an interesting dynamical fine-tuning mechanism that gives rise to a combined equation of state parameter $\omega \simeq -1$ and, therefore, to an eternal period of accelerated isotropic expansion for an ample spectrum of initial conditions. Regarding primordial inflation, one of the critical points of the associated dynamical system can describe a prolonged period of isotropic slow-roll inflation sustained by the $S$ term. This period ends up when the Yang-Mills term dominates the energy density leading to the radiation dominated epoch. Unfortunately, in contrast to the dark energy case, the primordial inflation scenario is strongly sensitive to the coupling constants and initial conditions. The whole model, including the other pieces of the Lagrangian that involve $S_{\mu \nu}$, might evade the recent strong constraints coming from the gravitational wave signal GW170817 and its electromagnetic counterpart GRB 170817A.Comment: LaTeX file in RevTeX 4.1 style, 8 pages, 20 figures. v2: several changes here and there to improve the overall presentation of the paper. Primordial inflation section clarified. The viability of the model after the detection of the gravitational wave signal GW170817 and its electromagnetic counterpart GRB 170817A is discussed. v4: version published in Physics of the Dark Univers

Polymer brush collapse under shear flow

Shear responsive surfaces offer potential advances in a number of applications. Surface functionalisation using polymer brushes is one route to such properties, particularly in the case of entangled polymers. We report on neutron reflectometry measurements of polymer brushes in entangled polymer solutions performed under controlled shear, as well as coarse-grained computer simulations corresponding to these interfaces. Here we show a reversible and reproducible collapse of the brushes, increasing with the shear rate. Using two brushes of greatly different chain lengths and grafting densities, we demonstrate that the dynamics responsible for the structural change of the brush are governed by the free chains in solution rather than the brush itself, within the range of parameters examined. The phenomenon of the brush collapse could find applications in the tailoring of nanosensors, and as a way to dynamically control surface friction and adhesion

Területfejlesztés vagy iparpolitika?: A francia versenyképességi pólus program tapasztalatai

A tanulmány felvázolja a területfejlesztési és a verseny-, illetve iparpolitikának a metszetében elhelyezkedő francia versenyképességi pólusok kialakulásának előzményeit, elméleti hátterét, és az alig egy évtizedes múltra visszatekintő gyakorlati tapasztalatok összegzésére vállalkozik. A versenyképességi pólusok az innovációs szereplők hálózatos kapcsolataira épülnek, fejlődésüket a szereplők közti együttműködés minősége alakítja. Miközben a teljesítmény-szemléletű politikák a legdinamikusabban fejlődő régiókra összpontosítanak az ország európai és globális pozícióját szem előtt tartva, és a pólusok esetében is a legígéretesebb csúcsipari ágazatok támogatását szorgalmazzák, a közel fél évszázados múltú egyenlősítő célzatú területfejlesztési politikák céljai a pólusok nagy számával és a hagyományos, érettebb ágazatok támogatásával realizálódnak. A kettős célkitűzés egyidejűleg a pólusprogram esetében is nehezen teljesíthető, de mindmáig jelen van az ország jövőjét meghatározó területpolitikai vitákban

Climate change and the kidney

The worldwide increase in temperature has resulted in a marked increase in heat waves (heat extremes) that carries a markedly increased risk for morbidity and mortality. The kidney has a unique role not only in protecting the host from heat and dehydration but also is an important site of heat-associated disease. Here we review the potential impact of global warming and heat extremes on kidney diseases. High temperatures can result in increased core temperatures, dehydration, and blood hyperosmolality. Heatstroke (both clinical and subclinical whole-body hyperthermia) may have a major role in causing both acute kidney disease, leading to increased risk of acute kidney injury from rhabdomyolysis, or heat-induced inflammatory injury to the kidney. Recurrent heat and dehydration can result in chronic kidney disease (CKD) in animals and theoretically plays a role in epidemics of CKD developing in hot regions of the world where workers are exposed to extreme heat. Heat stress and dehydration also has a role in kidney stone formation, and poor hydration habits may increase the risk for recurrent urinary tract infections. The resultant social and economic consequences include disability and loss of productivity and employment. Given the rise in world temperatures, there is a major need to better understand how heat stress can induce kidney disease, how best to provide adequate hydration, and ways to reduce the negative effects of chronic heat exposure.Published versio

Integración de Puentes Térmicos en Programas de Simulación Dinámica de Edificios mediante el Método del Muro Equivalente

Libro de actas completo disponible en :http://repositorio.bib.upct.es:8080/dspace/handle/10317/4709Los puentes térmicos son zonas de la envolvente de un edificio en las que se produce una transmisión preferencial de calor cuya causa es una heterogeneidad geométrica o material. Los programas más utilizados de simulación energética de edificios, como DOE-2 [1] o EnergyPlus [2], se basan en una hipótesis unidimensional para modelar la transmisión de calor en los cerramientos. No obstante, evaluar la transferencia de calor en los puentes térmicos implica resolver un problema de conducción bi- o tridimensional en régimen transitorio. Es posible utilizar herramientas especializadas como Voltra [3] o HEAT2 [4], pero no son generalmente aplicables a simulaciones estacionales, debido a su alto coste computacional. Se hace necesario un paso intermedio que conecte las simulaciones globales de edificios con los modelos detallados de puentes térmicos. Una de las aproximaciones más prácticas es la del “muro equivalente”, que consiste en identificar los parámetros de un muro multicapa ficticio, de forma que su respuesta dinámica sea muy próxima a la del elemento real, que tiene efectos 2D o 3D. Esta identificación de parámetros se puede llevar a cabo mediante diversos métodos. En este trabajo se aplica el método de identificación propuesto por Kosny [5] para obtener muros equivalentes que representen los tipos más usuales de puentes térmicos presentes en la construcción residencial española.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech