Resource Wealth, Innovation and Growth in the Global Economy

We analyze the relative growth performance of open economies in a two-country model where different endowments of labor and a natural resource generate asymmetric trade. A resource-rich economy trades resource-based intermediates for final manufacturing goods produced by a resource-poor economy. Productivity growth in both countries is driven by endogenous innovations. The effects of a sudden increase in the resource endowment depend crucially on the elasticity of substitution between resources and labor in interme- diates' production. Under substitution (complementarity), the resource boom generates higher (lower) resource income, lower (higher) employment in the resource-intensive sector, higher (lower) knowledge creation and faster (slower) growth in the resource-rich economy. The resource-poor economy adjusts to the shock by raising (reducing) the relative wage, and experiences a positive (negative) growth effect that is exclusively due to trade.Endogenous Growth, Endogenous Technological Change, Natural Resources, International Trade.

Growth on a Finite Planet: Resources, Technology and Population in the Long Run

We study the interactions between technological change, resource scarcity and population dynamics in a Schumpeterian model with endogenous fertility. There exists a pseudo- Malthusian equilibrium in which population is constant and income grows exponentially: the equilibrium population level is determined by resource scarcity but is independent of technology. The stability properties are driven by (i) the income reaction to increased resource scarcity and (ii) the fertility response to income dynamics. If labor and resources are substitutes in production, income and fertility dynamics are self-balancing and the pseudo-Malthusian equilibrium is the global attractor of the system. If labor and resources are complements, income and fertility dynamics are self-reinforcing and drive the economy towards either demographic explosion or human extinction. Introducing a minimum resource requirement, we obtain a second steady state implying constant population even under complementarity. The standard result of exponential population growth appears as a rather special case of our model.Endogenous Innovation, Resource Scarcity, Population Growth, Fertility Choices

Sustainable Growth and Secular Trends

We fully characterize the transition to sustained growth of resource-constrained economies using a model of industrialization that reproduces key stylized facts of resource use and prices. Natural scarcity, endogenous demography and innovations generate different growth regimes: knowledge-based innovations can potentially feed productivity growth in the long run, but exhaustible primary inputs and population pressure may halt economic development at earlier stages. Our model reproduces two well-documented empirical regularities -- a U-shaped path of resource prices and a hump-shaped path of resource extraction -- as secular trends that arise across growth regimes. Resource use and prices reach their respective turning points at different stages of development, and we may observe a peak in extraction followed by a long period where both resource use and its market price fall. The decoupling of price and quantity dynamics hinges on general-equilibrium interactions between demography and three sources of endogenous technological change, namely, increases in the mass of intermediate firms, vertical innovations within each intermediate firm, and endogenous extraction costs affected by learning-by-doing in the primary sector

Impaired GABAB-mediated presynaptic inhibition increases excitatory strength and alters short-term plasticity in synapsin knockout mice

Synapsins are a family of synaptic vesicle phosphoproteins regulating synaptic transmission and plasticity. SYN1/2 genes are major epilepsy susceptibility genes in humans. Consistently, synapsin I/II/III triple knockout (TKO) mice are epileptic and exhibit severe impairments in phasic and tonic GABAergic inhibition that precede the appearance of the epileptic phenotype. These changes are associated with an increased strength of excitatory transmission that has never been mechanistically investigated. Here, we observed that an identical effect in excitatory transmission could be induced in wild-type (WT) Schaffer collateral-CA1 pyramidal cell synapses by blockade of GABABreceptors (GABABRs). The same treatment was virtually ineffective in TKO slices, suggesting that the increased strength of the excitatory transmission results from an impairment of GABABpresynaptic inhibition. Exogenous stimulation of GABABRs in excitatory autaptic neurons, where GABA spillover is negligible, demonstrated that GABABRs were effective in inhibiting excitatory transmission in both WT and TKO neurons. These results demonstrate that the decreased GABA release and spillover, previously observed in TKO hippocampal slices, removes the tonic brake of presynaptic GABABRs on glutamate transmission, making the excitation/inhibition imbalance stronger

Increased responsiveness at the cerebellar input stage in the PRRT2 knockout model of paroxysmal kinesigenic dyskinesia

PRoline-Rich Transmembrane protein-2 (PRRT2) is a recently described neuron-specific type-2 integral membrane protein with a large cytosolic N-terminal domain that distributes in presynaptic and axonal domains where it interacts with several presynaptic proteins and voltage-gated Na+ channels. Several PRRT2 mutations are the main cause of a wide and heterogeneous spectrum of paroxysmal disorders with a loss-of-function pathomechanism. The highest expression levels of PRRT2 in brain occurs in cerebellar granule cells (GCs) and cerebellar dysfunctions participate in the dyskinetic phenotype of PRRT2 knockout (KO) mice. We have investigated the effects of PRRT2 deficiency on the intrinsic excitability of GCs and the input-output relationships at the mossy fiber-GC synapses. We show that PRRT2 KO primary GCs display increased expression of Na+ channels, increased amplitude of Na+ currents and increased length of the axon initial segment, leading to an overall enhancement of intrinsic excitability. In acute PRRT2 KO cerebellar slices, GCs were more prone to action potential discharge in response to mossy fiber activation and exhibited an enhancement of transient and persistent Na+ currents, in the absence of changes at the mossy fiber-GC synapses. The results support a key role of PRRT2 expressed in GCs in the physiological regulation of the excitatory input to the cerebellum and are consistent with a major role of a cerebellar dysfunction in the pathogenesis of the PRRT2-linked paroxysmal pathologies

Tuned mass dampers for improving the sustainability and resilience of seven reinforced concrete chimneys under environmental loads

In the late 1950s, driven by economic development and environmental considerations, industrial plants began utilizing reinforced concrete (RC) for chimney construction, lacking specific earthquake-resistance provisions. However, RC chimneys exhibit an inelastic response and a potential for brittle collapse under seismic loads. The reconstruction of these chimneys presents a challenge, considering their significant symbolic value within the community and the increasing focus on sustainability, material recycling, and environmental resilience. In response to this need, we explore the performance of seven historic RC chimneys retrofitted with Tuned Mass Dampers (TMDs). This study considers the nonlinear material properties of concrete and steel rebars subjected to five European earthquakes. The TMDs’ effectiveness is evaluated by their impact on top displacement, base shear, and base moment. Additional aspects, such as equivalent damping and mode changes, are scrutinized. Through a parametric investigation, we analyze the influence of slenderness ratio, taper ratio, height, and vertically distributed mass on chimney response to earthquakes. Notably, the slenderness ratio emerges as a crucial factor affecting mass ratio, optimizing TMD parameters, base shear, and base moment. Notably, geometric characteristics seem to exert minimal influence on equivalent damping. Additionally, examining energy dissipated by TMDs reveals their contribution to increased elastic damping energy in chimneys, concurrently reducing kinetic and hysteretic (inelastic) energies. Elastic damping energy involves dissipation through inherent system elasticity, while hysteretic damping encompasses energy dissipation due to material damping effects. This research sheds light on the potential of TMDs in enhancing the seismic resilience of historic RC chimneys and provides insights into the key parameters influencing their performance

Maternal Anti-Ro/SSA Autoantibodies and Prolonged PR Interval in a Competitive Athlete: Beyond Training-Induced Electrical Remodeling

: Prolongation of the PR interval is common among competitive athletes. However, further investigations should be performed when the PR interval is markedly prolonged. We report the case of a young male athlete with an autoimmune-mediated atrioventricular block due to circulating anti-Ro/SSA-antibodies in the mother (late progressive congenital form). (Level of Difficulty: Advanced.)

Endogenous growth and property rights over renewable resources

We study how different regimes of access rights to renewable natural resources - namely, open access versus full property rights – affect sustainability, growth and welfare in the context of modern endogenous growth theory. Resource exhaustion may occur under both regimes but is more likely to arise under open access. Moreover, under full property rights, positive resource rents increase expenditures on manufacturing goods and temporarily accelerate productivity growth, but also yield a higher resource price at least in the short-to-medium run. We characterize analytically and quantitatively the model’s dynamics to assess the welfare implications of differences in property rights enforcement

Adaptação e eficiência de um índice para análise da integridade biótica em Floresta Ombrófila Densa

Among the different ways of measuring the biotic integrity of a particular forest area, the Rapid Ecological Assessment (REA) stands out. Based on REA, an index was developed to evaluate the quality of the vegetation called the Biotic Integrity Index (BII). The measurement and accuracy of this index show how integral is the forest ecosystem at moment of analysis. The basis for efficiency in the application of BII is the correct choice of biotic integrity indicators or the variables to be measured. The present study was based from an index previously proposed for a Seasonal Semideciduous Forest (SSF), and aimed to adapt the BII for use in an area of Dense Ombrophilous Forest (DOF) in the State of São Paulo as well as to test its efficiency in diagnosing the integrity of fragments of a Tropical Rain Forest (TRF) inserted in a rural matrix. From the eleven indicators present in the original method, some were kept as original or adapted, some removed and some new ones were created. The adapted BII was applied in a TRF area of 70 hectares. To do so, 20 plots of 10x10m were used, within the sampling area. The results showed a variation of IIB from 28 to 47, and 2 plots recorded low integrity, 11 medium integrity and 7 good integrity. The area showed regular integrity as a whole, which was expected due to its size, agricultural surrounding and history of disturbances. The BII showed to be adapted and efficient to analyze the biotic integrity of the DOF, as it was able to show the difference of integrity between different patches of TRF. The least efficient indicators were: "litter cover" and "exotic woody species”, and the most efficient were: “Euterpe edulis”, “epiphytes”, “gaps” and “vines”. Diante dos diversos métodos de mensuração da integridade biótica de determinada área de floresta evidencia-se a Avaliação Ecológica Rápida (AER). Com base na AER foi desenvolvido um índice para avaliar a condição da vegetação, denominado Índice de Integridade Biótica (IIB). A aferição e precisão deste índice retratam o quão íntegro um dado ecossistema florestal se encontra no momento da análise. O alicerce para a eficiência na aplicação do IIB está na escolha correta dos indicadores de integridade biótica, ou seja, nas variáveis a serem mensuradas. O presente estudo partiu de um índice anteriormente proposto para Floresta Estacional Semidecidual (FES), e teve como objetivo adaptar o IIB para uso em área de Floresta Ombrófila Densa no Estado de São Paulo, bem como testar sua eficiência no diagnóstico da integridade de fragmentos de Floresta Ombrófila Densa (FOD) inseridos em matriz rural. Dos onze indicadores presentes no método original, alguns foram mantidos como no original ou adaptados, alguns retirados e alguns novos foram criados. O IIB adaptado foi aplicado numa área de FOD de 70 hectares. Para isso, foram utilizadas 20 parcelas de 10x10m, dentro da área amostral. Os resultados mostraram uma variação do IIB entre 28 e 47, ou seja, 2 parcelas registraram integridade baixa, 11 integridade média e 7 integridade boa. A área como um todo apresentou integridade regular, o que era esperado devido ao seu tamanho, ao entorno agrícola e ao histórico de perturbações. O IIB mostrou-se adaptado e eficiente para análise da integridade biótica da FOD, pois conseguiu mostrar a diferença de integridade entre diferentes trechos de Floresta Ombrófila Densa. Os indicadores menos eficientes foram: “cobertura de serapilheira” e “espécies exóticas lenhosas”. Os mais eficientes foram: “Euterpe edulis”, “epífitas”, “clareiras” e “cipós/lianas”

Crowded space: A review on radar measurements for space debris monitoring and tracking

Space debris monitoring is nowadays a priority for worldwide space agencies, due to the serious threat that these objects present. More and more efforts have been made to extend the network of available radar systems devoted to the control of space. A meticulous review has been done in this paper, in order to find and classify the considerable amounts of data provided by the scientific community that deal with RADAR measurement for the debris monitoring and tracking. The information gathered is organized based on the volume of found data and classified taking into account the geographical location of the facilities