31,771 research outputs found

    Complementarities, Costly Investment and Multiple Equilibria in a One-Sector Endogenous Growth Model

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    In this paper we develop a multiple equilibria one-sector R&D-based growth model, in which the key aspects are the assumption of complementarities between capital goods in the production function and the assumption of costly investment in capital. This second assumption is new to the R&D-based literature. The equilibrium solutions are obtained when the Preferences curve, which mirrors consumers’ savings decisions, and the Technology curve, which represents equilibria on the production side, cross. The combination of the two key assumptions produces a non-linear Technology curve, which consequently crosses the Preferences curve more than once, thus generating multiple equilibria. A numerical solutions exercise obtains two equilibria. Application of the stability under learning criterion allows for the identification of the two equilibria as stable. Expectations can lead the economy to either the equilibrium characterised by high-growth and high-interest rates, or to the equilibrium characterised by low-growth and low-interest rates. Hence, with this model, we wish to contribute to endogenous growth literature by providing a mechanism to explain how an economy can experience multiple equilibria situations.Growth, R&D, complementarities, costly investment, multiple equilibria.

    A Nonscale Growth Model with R&D and Human Capital Accumulation

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    This paper presents an endogenous growth model that includes research and development and human capital accumulation. The model’s specification builds on the R&D-based structure of Romer’s [1990] model and introduces two functions: (1) A specification for the production of new designs that assumes no externalities and no inventions before time zero; and (2) A specification for the accumulation of human capital technically similar to that in Lucas [1988]. The model displays two main results. The first is that it eliminates the scale-effects prediction which is common to most R&D-based growth models, but which is not empirically supported. Secondly, the model offers a new prediction that growth depends positively on the ratio of final-good workers to researchers. Thus the model provides a theoretical explanation as to why developed countries have had rising numbers of researchers but not rising growth rates in the twentieth century.endogenous growth; research and development; human capital accumulation; scale-effects prediction; final-good workers to researchers ratio.

    Economic Policies and Bankruptcy Institutions: Brazil in a Period of Transition from Colony to Independent Nation

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    This paper studies the legislation on bankruptcy introduced into Brazil by D.João VI (1808-1821) and shows how this legislation was used in this period as an instrument of protection for certain specific economic activities. On one hand, this work deliberately seeks to incorporate institutions into the study of Brazilian economic history, based on the assumption that the lack of interest in the role played by these institutions has hindered a better understanding of the country’s economic development during the Nineteenth Century. On the other hand, this paper introduces new material for the purpose of re-assessing the economic policies enforced in this period. In fact the study of the bankruptcy legislation suggests that one of the Government’s main concern at the time was to promote the development of activities directly related to gold and sugar exports. Therefore the general and popular acceptance of the revolutionary character of the economic policy in this period is challenged.Institutions, Bankruptcy, D. João VI, Legislation

    Early Diagenesis of Lower Pliensbachian Sediments from the Algarve Basin (Portugal): Characterisation and Relation with Tectonic Evolution

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    The Lower Jurassic (Lower Pliensbachian) sedimentary record of the western end of the Algarve Basin (Portugal) is made of decimetric thick layers of limestone and dolomitized limestone with chert nodules and inter-layered chert beds. Most of the observable lithologies are the product of an early diagenetic evolution and the original lithological content of the formation included limestones, marls and calciclastic limestones. In this area the sedimentation was controlled by the tectonic stretching responsible for the evolution of the Algarve Basin, as well as by short-lived events of tectonic inversion. These episodes of tectonic inversion were responsible for the some uplift with the development of unconformities, sometimes with erosional surfaces separating the different sedimentary packages. The early diagenesis affecting the Lower Pliensbachian sediments is characterized by: (i) a mechanical event controlled by the syn-sedimentary stretching, responsible for the development of calciclastic dikes and nodules alignements; (ii) the substitution of the carbonates from the most permeable calciclastic limestone layers by silica, leading to the development of the observed cherts; (iii) the dolomitization of the preserved limestones; and (iv) the infilling of joints and normal fault planes by silica-rich fluids leading to the development of quartz veins. This set of diagenetic transformations took place before the Upper Pliensbachian which lacks the evidences of their occurrence. The whole-rock geochemical data of the carbonate and siliceous sediments of the Lower Pliensbachian revealed some affinities between both lithological types namely the lack of Ce anomalies and the presence of La anomalies in the REE patterns of all samples. The similarities between the carbonate lithologies which diagenetic evolution is marked by the replacement of calcite by dolomite and the siliceous sediments derived from the replacement of calcite by quartz establish a chemical connection between the two sets of rocks. This connection can be interpreted as a testimony of a common primary precursor for both lithological groups or as a testimony of a common character of the diagenetic fluids which interacted with the original sediments. The dolomitization changed the Sr isotopic signature increasing the 87Sr/86Sr ratios from 0.7073 in the unchanged limestone to a maximum value of 0.7113 in the dolomitized samples. This strong increase together with the 13C/12C and 18O/16O values support an external origin for the dolomitizing fluids. A possible origin for the diagenesis is meteoric water coming into the basin after weathering the country rocks. The hydrologic regime in the basin certainly underwent important changes during the uplift events associated to the mentioned tectonic inversion episodes and uplift allowing for input of water from land

    Early Diagenesis of Lower Pliensbachian Sediments from the Algarve Basin (Portugal): Characterisation and Relation with Tectonic Evolution

    Get PDF
    The Lower Jurassic (Lower Pliensbachian) sedimentary record of the western end of the Algarve Basin (Portugal) is made of decimetric thick layers of limestone and dolomitized limestone with chert nodules and inter-layered chert beds. Most of the observable lithologies are the product of an early diagenetic evolution and the original lithological content of the formation included limestones, marls and calciclastic limestones. In this area the sedimentation was controlled by the tectonic stretching responsible for the evolution of the Algarve Basin, as well as by short-lived events of tectonic inversion. These episodes of tectonic inversion were responsible for the some uplift with the development of unconformities, sometimes with erosional surfaces separating the different sedimentary packages. The early diagenesis affecting the Lower Pliensbachian sediments is characterized by: (i) a mechanical event controlled by the syn-sedimentary stretching, responsible for the development of calciclastic dikes and nodules alignements; (ii) the substitution of the carbonates from the most permeable calciclastic limestone layers by silica, leading to the development of the observed cherts; (iii) the dolomitization of the preserved limestones; and (iv) the infilling of joints and normal fault planes by silica-rich fluids leading to the development of quartz veins. This set of diagenetic transformations took place before the Upper Pliensbachian which lacks the evidences of their occurrence. The whole-rock geochemical data of the carbonate and siliceous sediments of the Lower Pliensbachian revealed some affinities between both lithological types namely the lack of Ce anomalies and the presence of La anomalies in the REE patterns of all samples. The similarities between the carbonate lithologies which diagenetic evolution is marked by the replacement of calcite by dolomite and the siliceous sediments derived from the replacement of calcite by quartz establish a chemical connection between the two sets of rocks. This connection can be interpreted as a testimony of a common primary precursor for both lithological groups or as a testimony of a common character of the diagenetic fluids which interacted with the original sediments. The dolomitization changed the Sr isotopic signature increasing the 87Sr/86Sr ratios from 0.7073 in the unchanged limestone to a maximum value of 0.7113 in the dolomitized samples. This strong increase together with the 13C/12C and 18O/16O values support an external origin for the dolomitizing fluids. A possible origin for the diagenesis is meteoric water coming into the basin after weathering the country rocks. The hydrologic regime in the basin certainly underwent important changes during the uplift events associated to the mentioned tectonic inversion episodes and uplift allowing for input of water from land

    Metabolic Diseases: a differential diagnosis of primary progressive multiple sclerosis

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    Objectives: The overall aim of our research project is to develop a Next Generation Sequencing strategy to identify metabolic disorders in 104 patients with a presumptive diagnosis of primary progressive MS.We would like to thank to MERCK, SA and NORTE2020 (NORTE-01-0246-FEDER-000014) for funding this Project.N/

    A Growth Model for the Quadruple Helix Innovation Theory

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    We propose a theoretical growth model with which to frame analytically the Quadruple Helix Innovation Theory (QHIT). The aim is to emphasise the investment in innovation transmission mechanisms in terms of economic growth and productivity gains, in one-high-technology sector, by stressing the role played by the helices of the Quadruple Helix Innovation Model: Academiaand Technological Infrastructures, Firms of Innovation, Government and Civil Society. In the existing literature, the relationship between the helices and respective impacts on economic growth does not appear clear. Results are fragiledue to data weakness and the inexistence of a theoretical framework to specify the relationship between the helices. Hence our motivation for providing the QHIT with a theoretical growth model. Our intent is to model the importance of emerging, dynamically adaptive, and transdisciplinary knowledge and innovation ecosystems to economic growth. We .nd that higher economic growth rate is obtained as a result of an increase in synergies and complementarities between different productive units, or an incease in productive government expenditure.Economic Growth; Quadruple Helix Innovation Model; Innovation Ecosystems.
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