8,115 research outputs found

    The carbon-saving behaviour of residential households

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    The housing sector in 2004 was accountable for about 30% of total UK carbon emissions. The magnitude of this figure represents a significant imperative for policymakers to act on the sector through behavioural change strategies. Energy efficiency in households might easily be considered as driven mainly by economic motives, but this would not explain why even cost-free behavioural changes, like switching the lights off more often, are not adopted more widely. Literature has mainly concentrated either on the economic motives of pro-environmental behaviours or on the relevance of attitudes to shape them. Little has been said so far on the interaction between attitudes and the so called contextual factors. Diekmann and Presindörfer (2003) outlined the “low-cost hypothesis” which argues that pro-environmental behaviours are driven by pro-environmental attitudes only in the presence of low costs. However, little is known about households’ perceptions of costs and benefits in relation to energy saving behaviour. We propose to develop the low-cost hypothesis with a theoretical approach integrating attitudinal research and rational choice literature and explaining the interaction between tangible and intangible costs and benefits.Furthermore, the importance of resources such as education, information and income is highlighted in order to explain the magnitude of the perception of the costs and benefits considered by households. Finally, the scope for policy intervention aimed at shaping perceived costs and benefits to help the drive towards pro-environmental behaviour is discussed

    The Very-Soft X-Ray Emission of X-Ray Faint Early-Type Galaxies

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    A recent re-analysis of Einstein data, and new ROSAT observations, have revealed the presence of at least two components in the X-ray spectra of X-ray faint early-type galaxies: a relatively hard component (kT>1.5 keV), and a very soft component (kT\sim 0.2-0.3 keV). We address the problem of the nature of the very soft component, and whether it can be due to a hot interstellar medium (ISM), or is most likely originated by the collective emission of very soft stellar sources. To this purpose, hydrodynamical evolutionary sequences for the secular behavior of gas flows in ellipticals have been performed, and the results are compared with the observational X-ray data: the very soft component could be entirely explained with a hot ISM only in galaxies where the depth of the potential well is quite shallow, otherwise the softest contribution to the X-ray emission comes certainly from stellar sources. As stellar soft X-ray emitters, we consider late-type stellar corone, supersoft sources such as those discovered by ROSAT in the Magellanic Clouds and M31, and RSCVn systems. We finally present a model for the X-ray emission of NGC4365, to reproduce in detail the results of the ROSAT pointed observation (PSPC spectrum and radial surface brightness distribution).Comment: Postscript file, 28 pages. For hardcopy of figures contact [email protected]. BAP 12-1993-040-DD

    Shot noise in resonant tunneling structures

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    We propose a quantum mechanical approach to noise in resonant tunneling structures, that can be applied in the whole range of transport regimes, from completely coherent to completely incoherent. In both limiting cases, well known results which have appeared in the literature are recovered. Shot noise reduction due to both Pauli exclusion and Coulomb repulsion, and their combined effect, are studied as a function of the rate of incoherent processes in the well (which are taken into account by means of a phenomenological relaxation time), and of temperature. Our approach allows the study of noise in a variety of operating conditions (i.e., equilibrium, sub-peak voltages, second resonance voltages), and as a function of temperature, explaining experimental results and predicting interesting new results.Comment: RevTeX file, 26 pages, 3 Postscript figures, uses epsf.sty. submitted to Phys. Rev.

    Functional Methods and Effective Potentials for Nonlinear Composites

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    A formulation of variational principles in terms of functional integrals is proposed for any type of local plastic potentials. The minimization problem is reduced to the computation of a path integral. This integral can be used as a starting point for different approximations. As a first application, it is shown how to compute to second-order the weak-disorder perturbative expansion of the effective potentials in random composite. The three-dimensional results of Suquet and Ponte-Casta\~neda (1993) for the plastic dissipation potential with uniform applied tractions are retrieved and extended to any space dimension, taking correlations into account. In addition, the viscoplastic potential is also computed for uniform strain rates.Comment: 20 pages, accepted for publication in JMP

    Are we spending too much to grow? The case of Structural Funds

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    We evaluate whether the impact of EU Structural and Cohesion Funds (EUF) on Member States’ regional economic growth depends on the intensity of treatment, measured by the normalized amount of funds distributed in each region. We use an original dataset that covers all the main sources of EUF and extend the regression discontinuity design to the case of continuous treatment. The results suggest an average positive effect on regional growth. The estimated conditional intensity-growth function is concave and presents a maximum value. Therefore, the exceeding funds could have been allocated to other lagging regions without reducing the effect on growth
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