The Dynamics of International Trade Patterns

This paper introduces new dynamic measures for examining changes in international trade patterns. Using data for 20 OECD countries over the 1980-2000 period, we show that inter-industry trade changes contrary to countries' previous specialisation are frequently the dominant form of trade expansion. The econometric analysis indicates that the observed changes in trade patterns were explained by initial endowments of human-capital and industry-specific changes in labour productivity and labour costs. The results also suggest that trade liberalisation induced an increase in the previous specialisation of larger OECD economies in industries with increasing returns to scale.Dynamics of international specialisation, trade liberalisation, technology transfers.

Gestão da Defesa Social e Mediação de Conflitos

O presente trabalho propõe analisar o Plano Estratégico de Segurança Interna de Cabo Verde- PESI (2009-2011), buscando compreender a relação entre a estratégia global do Governo sobre a Segurança no país e os objectivos preconizados no referido documento relativamente à Segurança Interna. No contexto da análise, inteirou-se das fases da elaboração do referido documento e suas abordagens sociológicas. Problematizam-se questões, nomeadamente: análise prospectiva de Godet (1999) e método de cenários de Grumbach (2002), fases e metodologia da elaboração do PESI (2009-2011), violência, violência criminal, criminalidade, segurança no contexto da globalização, segurança no espaço temporal cabo-verdiano, conceito estratégico de segurança interna, políticas públicas de segurança nacional, níveis de coordenação de segurança e cultura organizacional. Por fim, verificamos que o PESI (2009-2011) tem como objecto uma problemática que excede a sua competência orgânica. Em Cabo Verde existe o conceito de Defesa que engloba a Segurança Nacional, subentendendo a Segurança Interna, cuja competência orgânica, em termos de coordenação, pertence ao Conselho de Segurança Nacional. Deste modo, os objectivos estratégicos constantes do PESI (2009-2011) não alinham com a estrutura da gestão de Segurança Nacional de Cabo Verde

DETERMINANTS OF EXPORT DIVERSIFICATION AND SOPHISTICATION IN SUB-SAHARAN AFRICA

This paper studies the political and economic factors that determine successful export diversification (ED) and export sophistication (ES) strategies in the Sub-Saharan African (SSA) countries and also the way in which successful ED and sophistication strategies contribute to explain the improving in some of the millennium development goals (MDG). We run separate regressions for the determinants of ES and ED, using disaggregated data of the 48 SSA countries, from 1960 to 2005. The results suggest that better governance is an important determinant for the success of diversification and sophistication strategies in SSA. In particular the level of corruption, transparency and accountability are important factors in limiting or promoting the scope of diversification and the level of sophistication of the exports. The results also suggest that increases in human capital in SSA countries promote both ED and ES, showing that the level of education of the workforce is positively related with ES and ED, with higher levels of education (tertiary) playing a more important role in explaining ES, while lower levels of education (primary) being more important as determinants of ED. In the second part we explore the links between ED and ES and growth presenting evidence that ED and ES are linked to growth stability in SSA. This study also suggests that the Sub-Saharan countries that were more successful in achieving ED and ES tend to be more successful in improving the living conditions of their population. Using different variables of Infant Mortality (one of the MDG) and life expectancy as dependent variables, we present evidence that suggests that in SSA higher ED and ES are associated with lower infant mortality and higher life expectancy. We show that this result is robust, presenting positive and significant results even when a large number of different control variables are introduced, or when fixed effects and instrumental variables are considered. The evidence suggests that ED and ES are part of the solution for a successful development of SSA. JEL codes:

Endowment Differences and the Composition of Intra-Industry Trade

This paper investigates the relationship between differences in endowments and different types of trade, in particular vertical intra-industry trade (VIIT). We build a general equilibrium framework based on a hybrid of the Chamberlain-Heckscher-Ohlin and the specific factors models that generates predictions about how the shares of different types of intra-industry and net trade flows change with differences in endowments. We also present some empirical evidence for European Union trade with its 51 major trading partners. The econometric models of the determinants of the different types of trade confirm the theoretical predictions, namely that the effect of cross country differences in the endowments of trading partners on the share of vertical IIT in total bilateral trade differs from their effect on both horizontal IIT and net trade. The share of horizontal IIT (net trade) decreases (increases) for all increases in absolute endowment differences, but the share of vertical IIT can both increase and decrease with increases in endowment differences.Intra-industry trade, factor endowments

Intra-industry trade expansion and employment reallocation between sectors and occupations

This paper re-examines the relationship between trade and labour market adjustment costs by explicitly considering the effects of occupational mobility. We investigate the hypothesis that intra-industry trade expansion entails lower adjustment costs than inter-industry trade expansion—the so-called Smooth Adjustment Hypothesis (SAH). This paper makes two new contributions. First, the introduction of a new adjustment variable that considers reallocation between sectors and occupations. Second, a test of the SAH using panel data with relevant trade and non-trade control variables, which overcomes some of the methodological limitations of former studies. The results suggest a confirmation of the SAH and stress the importance of considering the effects of worker moves between occupations in the study of trade-induced adjustment

Development of chitosan-based microparticles for pulmonary drug delivery

Dissertação para obtenção do Grau de Mestre em Engenharia Química e BioquímicaIn this work, novel chitosan (CHT) based microparticles were prepared using supercritical assisted atomization (SAA) and evaluated as potential carriers for sustained pulmonary drug delivery. CHT is a polysaccharide comprising of glucosamine and N-acetylglucosamine units, it is biodegradable, biocompatible and non-toxic being an interesting choice to be used as a drug carrier for inhalation therapy and belongs to the group of swellable polymers. By utilizing SAA, spherical microparticles containing a sharp particle distribution were successfully produced. Ibuprofen (IBP) and bovine serum albumin (BSA) were tested as a model small drug and as a model protein, respectively, to assess the effect on particle size and morphology when co-atomized with CHT on the SAA apparatus. The strategy developed in this work was to produce drug loaded microparticles with suitable aerodynamic characteristics that attain large geometric diameters when in contact with the lung physiological fluids by polymer swelling, reducing macrophage clearance. The microparticles produced by this method were characterized by using Morphologi G3 and Scanning electron microscopy (SEM) to assess their size distribution and morphology. To characterize the solid state properties of the particles X-ray diffraction (XRD), differential scanning calorimetry DSC and Fourier transform infrared (FTIR) were used. Porosity and surface area were determined by mercury and nitrogen porosimetry. In vitro aerosolization studies using an Andersen Cascade Impactor (ACI) were performed to determine the average emitted fraction (EF%) and the fine particle fraction (FPF). Drug-release profiles were determined by in vitro experiments at physiological pH and temperature conditions. The results obtained in this work show that SAA can be successfully used to prepare chitosan based formulations with adequate respirable fractions and sustained release of different bioactive molecules to be administered to the deep lung using dry powder inhalers (DPI).Fundação para a Ciência e Tecnologia - contracts PEst-C/EQB/LA0006/2011, PTDC/EQU-EQU/116097/2009, Conselho de Reitores das Universidades Portuguesas (CRUP) through Luso-German Agreement A - 13/ 10 and from Fundação Calouste Gulbenkian is acknowledge

3D numerical modelling of subduction initiation at a passive margin

Tese de mestrado em Ciências Geofísicas (Geofísica Interna), apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012A subducção é um processo chave na teoria da tectónica de placas. Todavia, apesar de todos os esforços realizados nas últimas décadas no estudo deste processo, o início da subducção ainda não é totalmente compreendido. Actualmente, não existem claras evidências da passagem de margens passivas para margens activas, muito embora as margens passivas representem os locais mais prováveis para a ocorrência de subducção. É actualmente aceite que a litosfera oceânica apresenta um valor negativo de impulsão que favorece o início da subducção, contudo o balanço entre as forças de atrito e elásticas (como forças resistivas) e as forças de abertura oceânica e gravitacionais (como forçadoras) previne o início de subducção. Desta forma, outros parâmetros devem ser tidos em conta para explicar o início da subducção, tais como a espessura da crosta continental e da litosfera continental e ainda os contrastes laterais de densidade entre as litosferas oceânica e continental. Os estudos mais recentes tentam perceber o problema através de modelos analíticos, analógicos e numéricos, todavia, todos os estudos consideram as zonas de subducção como um problema 2D, embora estas zonas tenham formas 3D na natureza. Tendo em conta as formas mais complexas das margens passivas tentamos neste trabalho, através de modelação numérica 3D, investigar os efeitos de diferentes geometrias da fronteira entre o oceano e o continente no início da subducção e testar se existem assim geometrias mais favoráveis ao início da subducção. Os resultados dos nossos testes indicam que a geometria sem variação entre as placas litosféricas é mais provável para o início da subducção, visto que nos testes com geometrias da fronteira oceano-continente a variar na terceira dimensão aumentarem o tempo para a ocorrência de subducção ou até impossibilitarem o início de subducção.Subduction is one of the key processes in the plate tectonics theory. However, despite all efforts in the last decades studying this problem, subduction initiation at passive margins is not yet fully understood. Present-day transition from passive to active margin is not obvious, although passive margins look like the most probable places for subduction initiation to occur. Despite the favourable negative buoyancy of oceanic lithosphere, the force balance between elastic and frictional forces (as resisting forces) and ridge push and gravitational forces (as driving forces) seems to inhibit the initiation of subduction. Therefore, other parameters must be taken into account in subduction initiation, like thickness of continental crust and lithosphere, and lateral density contrasts between continental and oceanic lithospheres. The recent studies that tried to solve this enigma vary from analytical, analogue and numerical approaches; however all of them treat the subduction zone as a 2D problem, despite these zones have a 3D shape. Given the complex shape of most passive margins, we use numerical modelling in 3D to investigate the effects of different geometries of continental-oceanic boundaries on subduction initiation, and to test if one of these geometries is more prone to initiate subduction. Our results show that the most prone geometry to initiate subduction at a passive margin is the usual third dimension invariant, common of the 2D models (without any angle in the the oceanic-continental boundary respecting to third dimension). More, our results indicate that with the increasing angle in the oceanic-continental lithospheres (e.g. 20, 40 or 60 degrees) the subduction tend to be retard, and for the highest angels the subduction can be even prevented

Optimization of the interoperability and dynamic spectrum management in mobile communications systems beyond 3G

The future wireless ecosystem will heterogeneously integrate a number of overlapped Radio Access Technologies (RATs) through a common platform. A major challenge arising from the heterogeneous network is the Radio Resource Management (RRM) strategy. A Common RRM (CRRM) module is needed in order to provide a step toward network convergence. This work aims at implementing HSDPA and IEEE 802.11e CRRM evaluation tools. Innovative enhancements to IEEE 802.11e have been pursued on the application of cross-layer signaling to improve Quality of Service (QoS) delivery, and provide more efficient usage of radio resources by adapting such parameters as arbitrary interframe spacing, a differentiated backoff procedure and transmission opportunities, as well as acknowledgment policies (where the most advised block size was found to be 12). Besides, the proposed cross-layer algorithm dynamically changes the size of the Arbitration Interframe Space (AIFS) and the Contention Window (CW) duration according to a periodically obtained fairness measure based on the Signal to Interference-plus-Noise Ratio (SINR) and transmission time, a delay constraint and the collision rate of a given machine. The throughput was increased in 2 Mb/s for all the values of the load that have been tested whilst satisfying more users than with the original standard. For the ad hoc mode an analytical model was proposed that allows for investigating collision free communications in a distributed environment. The addition of extra frequency spectrum bands and an integrated CRRM that enables spectrum aggregation was also addressed. RAT selection algorithms allow for determining the gains obtained by using WiFi as a backup network for HSDPA. The proposed RAT selection algorithm is based on the load of each system, without the need for a complex management system. Simulation results show that, in such scenario, for high system loads, exploiting localization while applying load suitability optimization based algorithm, can provide a marginal gain of up to 450 kb/s in the goodput. HSDPA was also studied in the context of cognitive radio, by considering two co-located BSs operating at different frequencies (in the 2 and 5 GHz bands) in the same cell. The system automatically chooses the frequency to serve each user with an optimal General Multi-Band Scheduling (GMBS) algorithm. It was shown that enabling the access to a secondary band, by using the proposed Integrated CRRM (iCRRM), an almost constant gain near 30 % was obtained in the throughput with the proposed optimal solution, compared to a system where users are first allocated in one of the two bands and later not able to handover between the bands. In this context, future cognitive radio scenarios where IEEE 802.11e ad hoc modes will be essential for giving access to the mobile users have been proposed