Development of an integrated methodology for the sustainableenvironmental and socio-economic management of river ecosystems

The development of theWater Framework Directive aimed to establish an integrated framework of water management at European level. This framework revolves around inland surface waters, transitional waters, coastal waters and groundwaters. In the process of achieving the environment and ecological objectives set fromthe Directive, the role of economics is put in the core of thewatermanagement. An important feature of the Directive is the recovery of total economic cost of water services by all users. The total cost of water services can be disaggregated into environmental, financial and resource costs. Another important aspect of the directive is the identification of major drivers and pressures in each River Basin District.We describe a methodology that is aiming to achieve sustainable and environmental and socioeconomic management of freshwater ecosystem services. The EcosystemServices Approach is in the core of the suggested methodology for the implementation of a more sustainable and efficientwater management. This approach consists of the following three steps: (i) socio-economic characterization of the River Basin area, (ii) assessment of the current recovery of water use cost, and (iii) identification and suggestion of appropriate programs of measures for sustainablewatermanagement over space and time. Thismethodology is consistent with a) the economic principles adopted explicitly by theWater Framework Directive (WFD), b) the three-step WFD implementation approach adopted in the WATECO document, c) the Ecosystem Services Approach to valuing freshwater goods and services to humans. Furthermore, we analyze how the effects ofmultiple stressors and socio-economic development can be quantified in the context of freshwater resources management.We also attempt to estimate the value of four ecosystemservices using the benefit transfer approach for the Anglian River Basin, which showed the significance of such services

Coherent and incoherent bands in La and Rh doped Sr3Ir2O7

In Sr2IrO4 and Sr3Ir2O7, correlations, magnetism and spin-orbit coupling compete on similar energy scales, creating a new context to study metal-insulator transitions (MIT). We use here Angle-Resolved photoemission to investigate the MIT as a function of hole and electron doping in Sr3Ir2O7, obtained respectively by Ir/Rh and Sr/La substitutions. We show that there is a clear reduction as a function of doping of the gap between a lower and upper band on both sides of the Fermi level, from 0.2eV to 0.05eV. Although these two bands have a counterpart in band structure calculations, they are characterized by a very different degree of coherence. The upper band exhibits clear quasiparticle peaks, while the lower band is very broad and loses weight as a function of doping. Moreover, their ARPES spectral weights obey different periodicities, reinforcing the idea of their different nature. We argue that a very similar situation occurs in Sr2IrO4 and conclude that the physics of the two families is essentially the same

Time-resolved PhotoEmission Spectroscopy on a Metal/Ferroelectric Heterostructure

In thin film ferroelectric capacitor the chemical and electronic structure of the electrode/FE interface can play a crucial role in determining the kinetics of polarization switching. We investigate the electronic structure of a Pt/BaTiO3/SrTiO3:Nb capacitor using time-resolved photoemission spectroscopy. The chemical, electronic and depth sensitivity of core level photoemission is used to probe the transient response of different parts of the upper electrode/ferroelectric interface to voltage pulse induced polarization reversal. The linear response of the electronic structure agrees quantitatively with a simple RC circuit model. The non-linear response due to the polarization switch is demonstrated by the time-resolved response of the characteristic core levels of the electrode and the ferroelectric. Adjustment of the RC circuit model allows a first estimation of the Pt/BTO interface capacitance. The experiment shows the interface capacitance is at least 100 times higher than the bulk capacitance of the BTO film, in qualitative agreement with theoretical predictions from the literature.Comment: 7 pages, 10 figures. Submitted to Phys. Rev.

Interface Electronic Structure in a Metal/Ferroelectric Heterostructure under Applied Bias

The effective barrier height between an electrode and a ferroelectric (FE) depends on both macroscopic electrical properties and microscopic chemical and electronic structure. The behavior of a prototypical electrode/FE/electrode structure, Pt/BaTiO3/Nb-doped SrTiO3, under in-situ bias voltage is investigated using X-Ray Photoelectron Spectroscopy. The full band alignment is measured and is supported by transport measurements. Barrier heights depend on interface chemistry and on the FE polarization. A differential response of the core levels to applied bias as a function of the polarization state is observed, consistent with Callen charge variations near the interface.Comment: 9 pages, 8 figures. Submitted to Phys. Rev.

Ordered droplet structures at the liquid crystal surface and elastic-capillary colloidal interactions

We demonstrate a variety of ordered patterns, including hexagonal structures and chains, formed by colloidal particles (droplets) at the free surface of a nematic liquid crystal (LC). The surface placement introduces a new type of particle interaction as compared to particles entirely in the LC bulk. Namely, director deformations caused by the particle lead to distortions of the interface and thus to capillary attraction. The elastic-capillary coupling is strong enough to remain relevant even at the micron scale when its buoyancy-capillary counterpart becomes irrelevant.Comment: 10 pages, 3 figures, to be published in Physical Review Letter