231 research outputs found
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
Wisconsin–Brittany CF Newborn Screening Study: Comparison of progression of lung disease using the Wisconsin Chest X-ray scoring system in two screened cohorts
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