Optimal education and pensions in an endogenous growth model

It is well known that, in OLG economies with life-cycle saving and exogenous growth, competitive equilibria will in general fail to achieve optimality and may even be dynamically inefficient. This is a consequence of individuals accumulating amounts of physical capital that differ from the level which would maximize welfare along a balanced growth path (the Golden Rule). With human capital, a second potential source of departure from optimality arises, to wit: individuals may not choose the correct amount of education investment. However, the Golden Rule concept, widely used in exogenous growth frameworks, has not found its way into endogenous growth models. In this paper, we propose to recover the Golden Rule of physical and also human capital accumulation. The optimal policy to decentralize the Golden Rule balanced growth path when there are no constraints for individuals to finance their education investments is also characterized. It is shown that it involves positive pensions and negative education subsidies (i.e., taxes)endogenous growth, human capital, intergenerational transfers, education policy

On welfare criteria and optimality in an endogenous growth model

In this paper we explore the consequences for optimality of a social planner adopting two different welfare criteria. The framework of analysis is an OLG model with physical and human capital. We first show that, when the SWF is a discounted sum of individual utilities defined over consumption per unit of natural labour, the precise cardinalization of the individual utility function becomes crucial for the characterization of the social optimum. Also, decentralizing the social optimum requires an education subsidy. In contrast, when the SWF is a discounted sum of individual utilities defined over consumption per unit of efficient labour, the precise cardinalization of preferences becomes irrelevant. More strikingly, along the optimal growth path, education should be taxed.endogenous growth, human capital, intergenerational transfers, education policy

The Fermi problem with artificial atoms in circuit QED

We propose a feasible experimental test of a 1-D version of the Fermi problem using superconducting qubits. We give an explicit non-perturbative proof of strict causality in this model, showing that the probability of excitation of a two-level artificial atom with a dipolar coupling to a quantum field is completely independent of the other qubit until signals from it may arrive. We explain why this is in perfect agreement with the existence of nonlocal correlations and previous results which were used to claim apparent causality problems for Fermi's two-atom system.Comment: 4 pages, 2 figures; typos corrected, introduction revised and experimental discussion extended, results unchange

Walking the Talk on Sustainable Development Goals: The Case of Community Foundations in Canada

The United Nations 2030 Agenda creates an opportunity for philanthropic foundations to become more collaborative and transformative in their work toward global goals. Thus, since 2016, the extent to which foundations adopt the Sustainable Development Goals framework in their functioning has become a topic of interest. Although survey- and case-based research shows increased rates of self-reported adoption and several tools are available to help foundations to act toward the goals, there is a lack of systematic evidence about the purposes of and processes for adopting the goals among foundations. This void is particularly relevant for community foundations, as they have been proposed as natural champions for the 2030 Agenda. This article provides global and national context to the process of adoption of the goals by Canadian community foundations through a multiple case study, tracing it back to its origins and disentangling its antecedents, enablers, and effects during the early implementation phase. Special attention is paid to the roles played by collective action by Community Foundations of Canada, by grassroots actors, and by innovative practices in that process of adoption. Conclusions point toward bottom-up social innovation originating in grassroots work that is diffused horizontally by Community Foundations of Canada to its member foundations, as a key antecedent. Enduring collaboration dynamics involving community foundations, prior engagement with data collection and a shared measurement framework, and space for local discussion and adaptation around the framework are identified as key enablers for adoption. Finally, early effects of adoption for mapping, reporting, and aligning purposes include reframing current work and promoting new activities and leadership roles, paving the way for new partnerships, and providing a coherent planning framework and strategic focus to grantmaking

Impact of metal-organic vapor phase epitaxy environment on silicon bulk lifetime for III–V-on-Si multijunction solar cells

With the final goal of integrating III-V materials on silicon substrates for tandem solar cells, the influence of the Metal-Organic Vapor Phase Epitaxy (MOVPE) environment on the minority carrier properties of silicon wafers has been evaluated. These properties will essentially determine the photovoltaic performance of the bottom cell in a III-V-on-Si tandem solar cell. A comparison of the base minority carrier lifetimes obtained for different thermal processes carried out in a MOVPE reactor on Czochralski silicon wafers has been carried out. An important degradation of minority carrier lifetime during the surface preparation (i.e. H2 anneal) has been observed. Three different mechanisms have been proposed for explaining this behavior: 1) the introduction of extrinsic impurities coming from the reactor; 2) the activation of intrinsic lifetime killing impurities coming from the wafer itself; and finally, 3) the formation of crystal defects, which eventually become recombination centers. The effect of the emitter formation by phosphorus diffusion has also been evaluated. In this sense, it has been reported that lifetime can be recovered during the emitter formation either by the effect of the P on extracting impurities, or by the role of the atomic hydrogen on passivating the defects

An integrated model system tool to evaluate the impact of urban mobility policies on air pollution: Barcelona case study

Air pollution remains as a key unresolved problem in many urban areas. Cities with such problem are gradually implementing Traffic Management Strategies (TMS) to reduce the total kilometers travelled by vehicles and subsequently decrease emissions. However, a prior evaluation of such TMS is needed if the target goals want to be achieved. In this sense, the combination of traffic simulation with emissions and air quality models can be of great use to assess the potential impacts of such policies. This study presents an integrated modelling system tool for Barcelona that allows to estimate the changes induced by the implementation of TMS on traffic activity, emissions and air quality levels at a very spatial (street level) and temporal (hourly level) resolution