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

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

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

Sustainable growth and environemtnal policies

A model of ecologically sustainable endogenous growth is presented, in which environmental quality has a positive influence on individual welfare and on the productivity of capital. The effect of different environmental policies on the long-run growth of the economy is studied in the framework of this model. The results establish that an optimal policy which taxes production and subsidises pollution abatement has a favourable effect on environmental quality, and could increase the growth rate if the positive external effects of the environment on the productivity are important. Furthermore, it is shown that this kind of environmental policy is neutral in budgetary terms, i.e. tax receipts are equal to subsidies. Finally, it is demonstrated that a policy based on emission control will only have a positive effect on the growth rate if the initial level of environmental quality is sufficiently low

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

La definición del patrimonio cultural subacuático en la Convención UNESCO de 2001

El texto analiza la definición que en el artículo 1.1 de la Convención sobre la Protección del Patrimonio Cultural Subacuático 2001 de la UNESCO se da del concepto de patrimonio cultural subacuático y llama la atención especialmente sobre cuatro aspectos: el contenido mismo de la definición, evitando calificar el patrimonio cultural subacuático; el límite temporal establecido de 100 años y su periodificación; la referencia al contexto natural; y las cuestiones relativas al uso actual del patrimonio cultural subacuático. Para explicar el alcance jurídico de la citada enunciación, Mariano J. Aznar repasa en su artículo el uso del concepto en textos internacionales previos. Finaliza apuntando el error de dejar fuera del régimen de protección del Convenio artes de pesca todavía en uso pero históricamente empleadas y recuerda la potestad de los estados de establecer en sus respectivas legislaciones internas un criterio de protección mayor

Sensitive and specific detection of Trypanosoma cruzi DNA in clinical specimens using a multi-target real-time PCR approach

Background: The laboratory diagnosis of Chagas disease is challenging because the usefulness of different diagnostic tests will depend on the stage of the disease. Serology is the preferred method for patients in the chronic phase, whereas PCR can be successfully used to diagnose acute and congenital cases. Here we present data using a combination of three TaqMan PCR assays to detect T. cruzi DNA in clinical specimens. Methods/Principal Findings: Included in the analysis were DNA extracted from 320 EDTA blood specimens, 18 heart tissue specimens, 6 umbilical cord blood specimens, 2 skin tissue specimens and 3 CSF specimens. For the blood specimens both whole blood and buffy coat fraction were analyzed. The specimens were from patients living in the USA, with suspected exposure to T. cruzi through organ transplantation, contact with triatomine bugs or laboratory accidents, and from immunosuppressed patients with suspected Chagas disease reactivation. Real-time PCR was successfully used to diagnose acute and Chagas disease reactivation in 20 patients, including one case of organ-transmitted infection and one congenital case. Analysis of buffy coat fractions of EDTA blood led to faster diagnosis in six of these patients compared to whole blood analysis. The three real-time PCR assays produced identical results for 94% of the specimens. The major reason for discrepant results was variable sensitivity among the assays, but two of the real-time PCR assays also produced four false positive results. Conclusions/Significance: These data strongly indicate that at least two PCR assays with different performances should be combined to increase the accuracy. This evaluation also highlights the benefit of extracting DNA from the blood specimen's buffy coat to increase the sensitivity of PCR analysis.Fil: Qvarnstrom, Yvonne. Centers for Disease Control and Prevention; Estados UnidosFil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Veron, Vincent. Centre hospitalier Andrée-Rosemon; Guayana FrancesaFil: Aznar, Christine. Centre hospitalier Andrée-Rosemon; Guayana FrancesaFil: Steurer, Francis. Centers for Disease Control and Prevention; Estados UnidosFil: da Silva, Alexandre J.. Centers for Disease Control and Prevention; Estados Unido