pH como un trazador de la variabilidad biogeoquimica en el Sistema de Humbodt

Se analizó información sobre parámetros biogeoquímicos como pH, CO2 parcialmente disuelto, clorofila-a, oxígeno, salinidad y temperatura, obtenidos en el Sistema de Humboldt frente a Peru en los años 2007-2009, a fin de comprender la importancia del pH como una variable clave para trazar la variabilidad biogeoquímica del Sistema de Afloramiento de Humboldt. Las Aguas Costeras Frías (ACF) ricas en nutrientes evidencian una relación inversa con el pH, en ese sentido valores de 7,6 a 8,0 se encontraron asociados a la ocurrencia de eventos de afloramiento; en condiciones frías como La Niña 2007 el pH predominante se encuentra por debajo de 8,0, y en el caso de las Aguas Subtropicales Superficiales presentan un pH entorno a 8,3. La productividad en los veranos se incrementa debido a factores como la intensidad de luz generándose nucleos de clorofila-a superiores a 10,0 μg.L-1; como constituyentes de la reacción bioquímica de fotosíntesis se tiene en cuenta la forma inmediata del compuesto CO2 y el consumo de iones hidronio; en situaciones extremas de fertilización, se tiene elevado pH entre 8,2 e inclusive 9,0, en donde los contenidos de oxígeno disuelto superan los 6,0 mL.L-1

Technological catching up, quality of exports and competitiveness: a sectoral perspective

In the paper we focus on emerging market economies’ pattern of trade, with a view to explaining the different features of competitiveness for high skill- and low skill-intensive firms. We consider a theoretical dynamical setup where high-skill firms engage in innovation activity and gain market shares in high-income ”quality dominated” markets thanks to technological catching up, whereas low-skill firms face price competition for their exports. On the basis of the theoretical model, we run econometric estimations for trade between CEECs and EU economies over the period 2000-2007. In the econometric analysis we first test the assumption that UVR is an adequate indicator of quality in trade, showing that in high skill-intensive firms it is systematically correlated to domestic and foreign technological variables; we then use the fitted UVR in the estimation of the role of preference for quality in the evolution of CEECs’ market shares. The estimations support the results of the theoretical model as to the role of non-price competitiveness stemming from quality-supply as well as quality-demand factors

Vertical Innovation and Catching-Up: Implications of EU Integration for CEECs-5

Vertical innovation, Technological catching up, Quality upgrading and trade, Economic integration, F01, F10, O40, O52, O57,

Investigando a hipótese da paridade do poder de compra: um enfoque não linear Testing the long-run purchasing power parity hypothesis: a nonlinear approach

A hipótese da Paridade do Poder de Compra (PPP) é investigada analisando-se a dinâmica de longo prazo da taxa de câmbio real efetiva no Brasil. Com dados mensais, o objetivo principal do estudo é testar a hipótese da PPP com um enfoque não linear. A metodologia empregada baseou-se na aplicação de testes gerais (Keenan, 1985; Tsay, 1986) e específicos para não linearidade do tipo Threshold (Chan, 1990). Seguindo-se a metodologia de Hansen (1999), o estágio seguinte consistiu em testar o número de regimes necessários para descrever a dinâmica não linear da taxa de câmbio real. Os resultados das estimações sugerem a ocorrência de apenas dois regimes distintos, com persistência e volatilidade diferentes. Conclui-se que a hipótese da PPP é apoiada pelos resultados.<br>We consider a threshold time series model in order to test the PPP hypothesis with Brazilian effective real exchange rate dataset in the long run. By following Keenan (1985), Tsay (1986) and Chan (1990), we test Brazilian dataset for several types of nonlinearities. So, after apply Hansen's test to infer about the number of regimes, we apply the more recent methodology of Self-Exciting Threshold Autoregressive (SETAR) model to point out some threshold to which a signal of turning point could be given in the states of the exchange rate dynamics. All the tests suggest that the Brazilian real exchange rate is highly nonlinear. The skeleton of the SETAR models fitted shows that PPP hypothesis is supported in the long run in spite the deviations from short run