194 research outputs found

    Trade-off between photovoltaic systems installation and agricultural practices on arable lands: An environmental and socio-economic impact analysis for Italy

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    The paper introduces and discusses an open-source spatial-based model (called r.green.solar) able to quantify the energy production from solar photovoltaic (PV) ground-mounted panels. Socio-economic and environmental impacts can be evaluated by the model. The model starts from the theoretical quantity of solar PV potential energy and estimates a reduction of total amount of energy based on legal, technical, recommended and economic constraints. Model outputs were used for a trade-off analysis between energy production and traditional crops for food/feed cultivation on not irrigated arable land. The model was tested at regional level for a Mediterranean context (Italy). The results confirm that the economic profitability of PV systems follows a north-south gradient, but the main impacts are related to local peculiarities – such as the disposal of not irrigated arable land and the presence of constraints, in particular the landscape maintenance, the morphological variables and the specialization index – and crop yields. © 2016 Elsevier Ltd. All rightsreserved

    Malinvaud on Wicksell’s legacy to capital theory: some critical remarks

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    This critique of Malinvaud’s article of 2003 on Wicksell’s legacy to capital theory focuses in particular on three points raised there. The first regards the given amount of existing capital that appears in Wicksell’s theory and its connection with his alleged “missing equation”, the second the particular notion of the marginal product of capital adopted by Malinvaud and the meaning of its equality with the rate of interest, and the third the concept of the average period of production taken by Malinvaud from Hicks and its inverse relation to the rate of interest

    Monetary Policy Rules and Directions of Causality: a Test for the Euro Area

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    Using a VAR model in first differences with quarterly data for the euro zone, the study aims to ascertain whether decisions on monetary policy can be interpreted in terms of a “monetary policy rule” with specific reference to the so-called nominal GDP targeting rule (Hall and Mankiw, 1994; McCallum, 1988; Woodford, 2012). The results obtained indicate a causal relation proceeding from deviation between the growth rates of nominal gross domestic product (GDP) and target GDP to variation in the three-month market interest rate. The same analyses do not, however, appear to confirm the existence of a significant inverse causal relation from variation in the market interest rate to deviation between the nominal and target GDP growth rates. Similar results were obtained on replacing the market interest rate with the European Central Bank refinancing interest rate. This confirmation of only one of the two directions of causality does not support an interpretation of monetary policy based on the nominal GDP targeting rule and gives rise to doubt in more general terms as to the applicability of the Taylor rule and all the conventional rules of monetary policy to the case in question. The results appear instead to be more in line with other possible approaches, such as those based on post Keynesian analyses of monetary theory and policy and more specifically the so-called solvency rule (Brancaccio and Fontana, 2013, 2015). These lines of research challenge the simplistic argument that the scope of monetary policy consists in the stabilization of inflation, real GDP, or nominal income around a “natural equilibrium” level. Rather, they suggest that central banks actually follow a more complex purpose, which is the political regulation of the financial system with particular reference to the relations between creditors and debtors and the related solvency of economic units

    Patterning and process parameter effects in 3D suspension near-field electrospinning of nanoarrays

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    The extracellular matrix (ECM) contains nanofibrous proteins and proteoglycans. Nanofabrication methods have received growing interest in recent years as a means of recapitulating these elements within the ECM. Near-field electrospinning (NFES) is a versatile fibre deposition method, capable of layer-by-layer nano-fabrication. The maximum layer height is generally limited in layer-by-layer NFES as a consequence of electrostatic effects of the polymer at the surface, due to residual charge and polymer dielectric properties. This restricts the total volume achievable by layer-by-layer techniques. Surpassing this restriction presents a complex challenge, leading to research innovations aimed at increasing patterning precision, and achieving a translation from 2D to 3D additive nanofabrication. Here we investigated a means of achieving this translation through the use of 3D electrode substrates. This was addressed by in-house developed technology in which selective laser melt manufactured standing pillar electrodes were combined with a direct suspension near-field electrospinning (SNFES) technique, which implements an automated platform to manoeuvre the pillar electrodes around the emitter in order to suspend fibres in the free space between the electrode support structures. In this study SNFES was used in multiple operation modes, investigating the effects of varying process parameters, as well as pattern variations on the suspended nanoarrays. Image analysis of the nanoarrays allowed for the assessment of fibre directionality, isotropy, and diameter; identifying optimal settings to generate fibres for tissue engineering applications
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