Endogenous Growth, Capital Utilization and Depreciation

We study the one sector model of growth when a linear production technology is combined with adjustment costs and a technology for capital maintenance. Agents are allowed to under-use the installed capital and to vary the depreciation rate. This economy decides endogenously how much resources devotes to the accumulation of new capital and how much to maintenance and repair activities. We find as striking results that the long-run depreciation and capital utilization rates are positively related to the population growth rate, and that both depend negatively on the initial conditions. The long-run growth rate appears positively correlated with the depreciation rate.Maintenance; Depreciation; Capital Utilization; Endogenous Growth

Closed-Form Solution for a Two-Sector Endogenous Growth Model with two Controls

In this paper we show a method for solving in closed form a particular family of four-dimension non-linear modified Hamiltonian dynamic systems, with two states and two co-states and two co-states, which arises from a two-sector endogenous growth model where the physical capital stock is combined with a renewable natural capital stock as essential inputs for productionNon-Linear Dynamic System, Analytical Solution, Endogenous Growth, Transitional Dynamics

Renewable Natural Resources and Endogenous Growth

We study a two-sector endogenous growth model where a single consumption good is obtained using a renewable resource in combination with physical capital. Both inputs are essential for production and technical substitutes. In this context we analyze the issues of sustainability, long-run and short-run growth as well as convergence, associated with the competitive equilibrium solution trajectories. We show that efficiency, long-run growth and sustainability are both compatible in a natural resource based production economy.Natural Capital, Endogenous Growth, Sustainability, Convergence

Non Catastrophic Endogenous Growth with Pollution and Abatment

When there are pollution externalities the competitive equilibrium is not Pareto-optimal nor environmentally sustainable even if abatment activities are endogenously decided. In this paper we introduce the possibility of an ecological catastrophe like the one predicted by the global climate change, imposing the constraint of an upper-limit to the pollutants stock. We characterize this socially optimal soclution and study conditions for the sustainability of the balanced growth path. We find a trade-off between environmental quality and growth. The rate of growth depends negatively on the weight of environmental care in the utility function and positively on the population growth rate. We show that the emissions reduction recommended in the Kioto protocol is an appropriate policy to avoid the ecological catastrophe and ensure global efficiency and positive long-run growth.Environment; Externalities; Optimal Growth, Ecological Catastrophe; Sustainability

Demographic Transition Environmental Concern and the Kuznets Curve

In an endogenous growth model with pollution and abatement we characterize the socially optimal solution. We find that the rate of growth depends negatively on the weight of environmental care in utility and positively on the population growth rate. We also find a trade-off between growth and environmental quality beyond which an environmental Kuznets curve is derived in the long term. This one emerges from the implications of the demographic transition for the rate of population growth, and the accompanying variation in the willingness to pay for environmental quality as the economy develops.Optimal Growth; Environment; Population Growth; Preferences

Actividad física, ejercicio y deporte en la lucha contra la obesidad infantil y juvenil

El propósito del presente documento es proponer desde el grupo de expertos en ejercicio físico y salud de EXERNET (Red Española de Investigación en Ejercicio Físico y Salud) una serie de recomendaciones sobre la práctica de la actividad física y deportiva que a nivel individual, familiar e institucional ayuden a prevenir y tratar la obesidad infantil y juvenil, basadas en la evidencia científi ca actual

Shrike predation on the lizard Mesalina adramitana in Qatar; a review of reported reptile and amphibian prey

We report, for the first time, evidence of predation by a shrike (Lanius sp.) on the lizard Mesalina adramitana. This is the first record of predation by shrikes on lizards in Qatar. Whilst we did not directly observe the event, the presence of shrikes in the area and the method of impalement indicate shrikes as the predator. The lizard was found freshly impaled on a palm tree (Phoenix dactylifera), at 150 cm above ground. Bird species of the genus Lanius are well-known predators of lizards, and in arid environments reptiles are likely common prey for these birds. We provide a review of literature concerning predatory events by shrikes on reptiles and amphibians. We suggest inspection of shrubs for animals impaled by shrikes can improve biodiversity inventories, complementing other commonly used methods