Aspirations, Habit Formation, and Bequest Motive

We analyze how the presence of endogenous preferences affects the altruistic bequest motive from parents to children. We will show that the existence of habits raises the threshold value of the intergenerational discount factor above which altruistic bequests are positive, while aspiration formation could push this value down. Therefore, the dynamic inefficiency of the economy with no altruism is not sufficient to prevent the bequest motive from being operative under aspiration formation. We also discuss the implications of public debt when the bequest motive is inoperative and preferences exhibit habit and aspiration formation.Aspirations, Habits, Bequests

Welfare Implications of the Interaction between Habits and Consumption Externalities

We analyze the welfare properties of the equilibrium path of a growth model where both habits and consumption externalities affect the utility of consumers. Our analysis highlights the crucial role played by complementarities between externalities and habits in order to generate an inefficient dynamic equilibrium. In particular, we show that the competitive equilibrium is inefficient when consumption externalities and habit adjusted consumption are not perfect substitutes.Habit formation, consumption externalities

Estate Taxes, Consumption Externalities, and Altruism

We study how the introduction of consumption externalities affects the efficiency of the dynamic equilibrium in an economy displaying dynastic altruism. When the bequest motive is inoperative consumption externalities affect the intertemporal margin between young and old consumption and thus modify the intertemporal path of consumption and capital. The optimal tax policy that solves this intertemporal inefficiency consists of a tax on capital income and a pay-as-you-go social security system. The later solves the overaccumulation of capital due to the inoperativeness of the bequest motive and the former solves the inefficient allocation of consumption due to consumption externalities. When the bequest motive is operative consumption externalities only cause an intratemporal inefficiency that affects the allocation of consumption between the generations living in the same period but do not affect the optimality of the capital stock level. This suboptimal allocation of consumption implies in turn that the path of bequest is also suboptimal. The optimal tax policy in this case consists of an estate tax and a capital income tax. The estate tax corrects the intratemporal inefficiency but generates an intertemporal inefficiency which is corrected by means of an appropriate capital income tax.Consumption externalities, bequests, optimal tax rates

Can consumption spillovers be a source of equilibrium indeterminacy?

In this paper, we show that consumption externalities are a source of equilibrium indeterminacy in a growth model with endogenous labor supply. In particular, when the marginal rate of substitution between own consumption and the others' consumption is constant along the equilibrium path, the equilibrium does not exhibit indeterminacy. In contrast, when that marginal rate of substitution is not constant, the equilibrium may exhibit indeterminacy even if the elasticity of the labor demand is smaller than the elasticity of the Frisch labor supply.Consumption externalities, equilibrium efficiency, indeterminacy

Consumption Externalities, Habit Formation, and Equilibrium Efficiency

We analyze the welfare properties of the competitive equilibrium in a capital accumulation model where individual preferences are subjected to both habit formation and consumption spillovers. We also discuss how consumption externalities and habits interact to generate an inefficient dynamic equilibrium. Finally, we characterize optimal tax policies aimed to restore efficient decentralized paths.Habit Formation, Consumption Externalities, Equilibrium Efficiency

Sectoral composition and macroeconomic dynamics

We analyze the transitional dynamics of a model with heterogeneous consumption goods. In this model, convergence is driven by two different forces: the typical diminishing returns to capital and the sectoral change inducing the variation in relative prices. We show that this second force affects the growth rate if the two consumption goods are not Edgeworth independent and if these two goods are pro- duced with technologies exhibiting different capital intensities. Because the afore- mentioned dynamic sectoral change arises only under heterogeneous consumption goods, the transitional dynamics of this model exhibits striking differences with the growth model with a single consumption good. We also show that these differences in the transitional dynamics can give raise to large discrepancies in the welfare cost of shocks between the economy with a unique consumption good and the economy with multiple consumption goods.multi-sector growth models, transitional dynamics, consumption growth.

Comparing the dynamics of periodically forced lasers and neurons

Neuromorphic photonics is a new paradigm for ultra-fast neuro-inspired optical computing that canrevolutionize information processing and artificial intelligence systems. To implement practicalphotonic neural networks is crucial to identify low-cost energy-efficient laser systems that can mimicneuronal activity. Here we study experimentally the spiking dynamics of a semiconductor laser withoptical feedback under periodic modulation of the pump current, and compare with the dynamics of aneuron that is simulated with the stochastic FitzHugh–Nagumo model, with an applied periodicsignal whose waveform is the same as that used to modulate the laser current. Sinusoidal and pulse-down waveforms are tested. Wefind that the laser response and the neuronal response to the periodicforcing, quantified in terms of the variation of the spike rate with the amplitude and with the frequencyof the forcing signal, is qualitatively similar. We also compare the laser and neuron dynamics usingsymbolic time series analysis. The characterization of the statistical properties of the relative timing ofthe spikes in terms of ordinal patterns unveils similarities, and also some differences. Our resultsindicate that semiconductor lasers with optical feedback can be used as low-cost, energy-efficientphotonic neurons, the building blocks of all-optical signal processing systems; however, the length ofthe external cavity prevents optical feedback on the chip.Peer ReviewedPostprint (published version

Europeos bajo la crisis: cambios en sus patrones migratorios recientes en España

De los más de 5 millones de inmigrantes extranjeros que España recibió en los últimos años, el principal contingente lo componen los europeos, con más de 2,6 millones de residentes en 2011, de los cuales 1,2 millones pertenecen a antiguos países de la UE-15 y 1,4 millones al resto de países europeos. Este artículo analiza los cambios recientes en las dinámicas migratorias de los residentes extranjeros de nacionalidad europea en España, centrando la atención en las consecuencias territoriales derivadas de la actual crisis económica. Se analizan tanto la composición de los stocks, como la evolución de los flujos migratorios externos e internos. Para ello se utiliza la información del Padrón Continuo de población y de las Estadísticas de Variaciones Residenciales, cubriendo la última década. Los resultados muestran un descenso considerable de las entradas migratorias a España desde 2008, al mismo tiempo que se observan variaciones significativas en sus pautas de movilidad interna, tanto en su intensidad como en las provincias emisoras y receptoras de los flujos, especialmente en aquellas provincias donde el sector de la construcción era importante y el impacto de la crisis ha sido mayor