International Trade Patterns over the Last Four Decades: How does Portugal Compare with other Cohesion Countries?

This paper compares the international trade pattern of Portugal with the other three EU15 Cohesion countries - Spain, Greece and Ireland - over the last forty years. The paper adopts a fact-finding approach, investigating the degree of openness of these economies and making extensive use of the standard Balassa (1965) index to assess the technological content of these countries' manufacturing trade. In order to infer on international trade specialization and on the persistence of trade patterns, the paper provides empirical evidence on the shape of the cross-sector distribution of 120 manufacturing exports and examines the intra-distribution dynamics. The Balassa index is also computed using import data, which allows for an assessment on the similitude of relative import structures and a crude identification of major vertical specialization activities. The paper concludes that there was a significant increase in the degree of openness of all economies, particularly in Ireland. Over the last four decades, Portugal shows a tendency to reduce its overall extent of export specialization, but significant differences with the world average still remain. The same behaviour is found in Greece and, more strongly, in Spain, which is the least specialized country. Conversely, Ireland shows the strongest export specialization and there is evidence of an increase in the last twenty years. The overall degree of specialization is higher on the export than on the import side, as the four countries analyzed show an import structure very close to the world average in the 2000-04 period. In the Portuguese case, we also find evidence that the degree of persistence of export patterns is higher than that of imports, in particular over longer horizons.

Relative Export Structures and Vertical Specialization: A Simple Cross-Country Index

Relative export structures have changed substantially over the last forty years. We map these changes using a new cross-country specialization index - the B* -, defined as the export weight of a given product on total domestic exports, “normalized” by the average weight across all countries of the world. This indicator is close to the Revealed Comparative Advantage index suggested in Balassa (1965); it has been used as an intermediate calculation in some papers but it has never been highlighted or interpreted as an alternative index in its own right. We provide empirical evidence on the shape of the distribution of the B* for different technological sectors (high, medium-high, medium-low and low-technology sectors), how it has evolved through time and how its intra-distribution dynamics behave. The results indicate a relatively important degree of persistence, although the cross-country specialization distributions depict substantial differences as we move up the technology ladder. Special attention is given to the G5 countries and China. These economies are relatively more specialized in high-tech and medium high-tech products. China shows a striking increase in specialization in high-tech products and a substantial decrease in low-tech. Finally, by computing the B* for both exports and imports, we have identified countries with significant vertical specialization activities. These activities are predominant in high-tech industries and seem to be geographically concentrated in East-Asia.

Computational predictions of interfacial tension, surface tension, and surfactant adsorption isotherms

All-atom (AA) molecular dynamics (MD) simulations are employed to predict interfacial tensions (IFT) and surface tensions (ST) of both ionic and non-ionic surfactants. The general AMBER force field (GAFF) and variants are examined in terms of their performance in predicting accurate IFT/ST, γ, values for chosen water models, together with the hydration free energy, ΔGhyd, and density, ρ, predictions for organic bulk phases. A strong correlation is observed between the quality of ρ and γ predictions. Based on the results, the GAFF-LIPID force field, which provides improved ρ predictions is selected for simulating surfactant tail groups. Good γ predictions are obtained with GAFF/GAFF-LIPID parameters and the TIP3P water model for IFT simulations at a water–triolein interface, and for GAFF/GAFF-LIPID parameters together with the OPC4 water model for ST simulations at a water–vacuum interface. Using a combined molecular dynamics-molecular thermodynamics theory (MD-MTT) framework, a mole fraction of C12E6 molecule of 1.477 × 10−6 (from the experimental critical micelle concentration, CMC) gives a simulated surface excess concentration, ΓMAX, of 76 C12E6 molecules at a 36 nm2 water–vacuum surface (3.5 × 10−10 mol cm−2), which corresponds to a simulated ST of 35 mN m−1. The results compare favourably with an experimental ΓMAX of C12E6 of 3.7 × 10−10 mol cm−2 (80 surfactants for a 36 nm2 surface) and experimental ST of C12E6 of 32 mN m−1 at the CMC