Price and Quality Regulation in a Physical Network Industry

Our paper models the relationship between price and quality regulation in a physical network industry. The analysis is closely inspired by some of the major regulatory features of the current organisation of the British railways industry, even though its insights have more general implications. Our model focuses on the combination of price and quality regulation and accounts for the existence of entry costs which create a competitive advantage for the incumbents in the competitive franchise bidding. We show that the effectiveness of the quality control is nonmonotone in the quality standard set by the Regulator. Moreover, we advance that price regulation negatively affects the extent to which the service quality can be controlled. By partially subsidising the entry costs, the Regulator can intensify the competition for the market and improve the regulation of the service quality. Nevertheless, since entry costs subsidisation involves social costs (e.g., distortionary taxation), the Regulator faces a trade-off between price regulation, on the one hand, and quality regulation and entry costs subsidisation, on the other hand.

Spintronic devices from bilayer graphene in contact to ferromagnetic insulators

Graphene-based materials show promise for spintronic applications due to their potentially large spin coherence length. On the other hand, because of their small intrinsic spin-orbit interaction, an external magnetic source is desirable in order to perform spin manipulation. Because of the flat nature of graphene, the proximity interaction with a ferromagnetic insulator (FI) surface seems a natural way to introduce magnetic properties into graphene. Exploiting the peculiar electronic properties of bilayer graphene coupled with FIs, we show that it is possible to devise very efficient gate-tunable spin-rotators and spin-filters in a parameter regime of experimental feasibility. We also analyze the composition of the two spintronic building blocks in a spin-field-effect transistor.Comment: 9 pages, 7 figures, revised version, a figure adde

Analytical model of 1D Carbon-based Schottky-Barrier Transistors

Nanotransistors typically operate in far-from-equilibrium (FFE) conditions, that cannot be described neither by drift-diffusion, nor by purely ballistic models. In carbonbased nanotransistors, source and drain contacts are often characterized by the formation of Schottky Barriers (SBs), with strong influence on transport. Here we present a model for onedimensional field-effect transistors (FETs), taking into account on equal footing both SB contacts and FFE transport regime. Intermediate transport is introduced within the Buttiker probe approach to dissipative transport, in which a non-ballistic transistor is seen as a suitable series of individually ballistic channels. Our model permits the study of the interplay of SBs and ambipolar FFE transport, and in particular of the transition between SB-limited and dissipation-limited transport

Corruption and production: a policy analysis.

� This paper analyzes the relation existing between corruption, monitoring and output in an economy. By solving a dynamic game we prove that equilibrium output is a non-linear upper-hemicontinuous function (MP function) of the monitoring level implemented by the State on corruption, presenting 3 different equilibrium scenarios. According to our model, we analyze the optimal strategy depending on the policy objective of the State and we prove that if the State is budget constrained the optimal policy can lead the economy to an equilibrium with widespread corruption and maximum production.Policy analysis,Equilibrium production,Corruption,Dynamic game

Analytical model of nanowire FETs in a partially ballistic or dissipative transport regime

The intermediate transport regime in nanoscale transistors between the fully ballistic case and the quasi equilibrium case described by the drift-diffusion model is still an open modeling issue. Analytical approaches to the problem have been proposed, based on the introduction of a backscattering coefficient, or numerical approaches consisting in the MonteCarlo solution of the Boltzmann transport equation or in the introduction of dissipation in quantum transport descriptions. In this paper we propose a very simple analytical model to seamlessly cover the whole range of transport regimes in generic quasi-one dimensional field-effect transistors, and apply it to silicon nanowire transistors. The model is based on describing a generic transistor as a chain of ballistic nanowire transistors in series, or as the series of a ballistic transistor and a drift-diffusion transistor operating in the triode region. As an additional result, we find a relation between the mobility and the mean free path, that has deep consequences on the understanding of transport in nanoscale devices

Screening properties and plasmons of Hg(Cd)Te quantum wells

Under certain conditions, Hg(Cd)Te quantum wells (QWs) are known to realize a time-reversal symmetric, two-dimensional topological insulator phase. Its low-energy excitations are well-described by the phenomenological Bernevig-Hughes-Zhang (BHZ) model that interpolates between Schr\"odinger and Dirac fermion physics. We study the polarization function of this model in random phase approximation (RPA) in the intrinsic limit and at finite doping. While the polarization properties in RPA of Dirac and Schr\"odinger particles are two comprehensively studied problems, our analysis of the BHZ model bridges the gap between these two limits, shedding light on systems with intermediate properties. We gain insight into the screening properties of the system and on its characteristic plasma oscillations. Interestingly, we discover two different kinds of plasmons that are related to the presence of intra- and interband excitations. Observable signatures of these plasmons are carefully analyzed in a variety of distinct parameter regimes, including the experimentally relevant ones for Hg(Cd)Te QWs. We conclude that the discovered plasmons are observable by Raman or electron loss spectroscopy

Chaos in credit–constrained emerging economies with Leontief technology

This work provides a framework to analyze the role of financial development as a source of endogenous instability in emerging economies subject to moral hazard problems. We study a piecewise linear dynamic model describing a small open economy with a tradable good produced by internationally mobile capital and a country specific production factor, using Leontief technology. We demonstrate that emerging markets could be endogenously unstable when large capital in–flows increase risk and exacerbate asymmetric information problems, according to empirical evidence. Using bifurcation and stability analysis we describe the properties of the system attractors, we assess the plausibility for complex dynamics and we find out that border collision bifurcations can emerge.border collision bifurcations,,complex dynamics,,emerging economies,,CEECs,,Endogenous instability,,moral hazard,,piecewise linear map.

Exchange rate policy and income distribution in an open developing economy

In this work we are going to deal with the issue of distribution of income in an open economy within a simplified macroeconomic model with constant prices.this type of model could apply to middle-income developing countries, which have succeeded in fighting inflation through a policy of high interest rates.It will be assumed that the implicit target of monetary policy now becomes the exchange rate and interest rates are set to a high level to lower the exchange rate. Even if this strategy may work it may produce negative effects on output growth and the distribution of income.The lowering of the exchange rate target would have the following effects on distribution.It would cause a reduction in the growth of output,it would lower the wage rate.Domestically-produced income distributed abroad should increase instead.The domestic interst rate would rise only for suitable small values of the parameter which links imports to income.The effect on the profit share is indeed uncertain.exchange rate policy balance of payments income distribution developing countries

When Consumption Generates Social Capital: Creating Room for Manoeuvre for Pro-Poor Policies

Economic interactions are often accused of being neutral, or even of generating adverse effects, not only on the social fabric but also on a factor (social capital) which is regarded as the foundation of both socio-economic activity and prosperity. In this paper we document how a particular form of economic interaction (affiliation of marginalised producers to a first level association and to the fair trade import channel) has indeed positive effects on a specific type of social capital. Our findings on a sample of Kenyan farmers show that years of affiliation to Fair Trade significantly affect the participation in elections and the trust placed in trade unions, political parties and the government, net of the impact of other controls and after accounting for the selection bias effect. This implies that consumers buying fair trade products contribute to reinforce both social cohesion and the institutions in countries in which these variables are fundamental in creating room for manoeuvre for pro-poor (equity plus growth) policies.Fair trade, social capital, impact study