Do we need handshakes to cooperate in buyer-supplier relationships?

Does formal contracting foster cooperation in a buyer-supplier relationship? In line with the literature, we find that a renegotiable contract with relationship-specific joint investments does not make it possible to reach the first-best. However, we show that a renegotiable contract may induce more cooperation than an informal arrangement. This result may help to understand how cooperation emerges in Japanese procurement practices, which typically involve relationship-specific joint investments and renegotiable contracts.Incomplete contracts, relationship-specific investments, cooperation

Trade and Colonial Status

Does colonisation explain differences in trade performance across developing countries? In this paper, we analyse the differential impact of British versus French colonial legacies on the current trade of African ex-colonies. We initially find that former British colonies trade more, on average, than do their French counterparts. This difference might be the result of the relative superiority of British institutions. However, a core concern is the non-random selection of colonies by the British. Historians argue that with Britain, trade preceded colonisation. Using an instrument based on colonisation history to control for this endogeneity, we find no evidence of a systematic difference between the British and French colonial legacies with respect to trade. This finding suggests that the apparent better performance of British ex-colonies might be instead explained by pre-colonial conditions.Trade, colonisation, Africa

Lord Holland's Contribution to the Abolition of the Transatlantic Slave Trade and its Impact on the Anglo-Portuguese Political and Diplomatic Relations

UID/ELT/04097/2013This article investigates the role of Lord Holland in the abolition of the Slave Trade and in the enforcement of abolition on other nations. Holland, nephew of Charles James Fox, was the embodiment of Whig idealism, yet there was ambiguity in his position. In the frst place much of Holland’s income came from a sugar plantation in Jamaica so that his support for the abolition of slavery itself was highly qualifed. Secondly, Holland was an ardent Lusophile and British attempts to suppress the Portuguese Slave Trade produced strains in an alliance that had lasted since the fourteenth century.publishersversionpublishe

A democracia e o fim da História

Revista Lusófona de Ciência das Religiõe

Applications of residues and poles in solutions of some improper integrals evaluation

In Physics, we are generally interested in real solutions involving natural phenomena, where knowledge of real functions of real variables is sufficient to obtain physically relevant results. However, the complexity of phenomena associated with nature lead us to situations where it is necessary to extend mathematical knowledge to complex values of complex variables for reasons of completeness and convenience. A relevant factor is that the real numbers do not form a sufficient basis for the representation of the roots of algebraic and polynomial equations, where the knowledge of the behavior of a complex function presents us with a more complete view of its main properties in comparison to the real variables. Therefore, the theoretical basis of complex variables aims to extend the differential and integral calculus in the representation of the domain of complex numbers. We present here the importance of the Theory of Complex Variables as a natural extension of the theory of real functions in solving basic mathematical problems involving improper Integrals, where its solution is obtained through the Theorem of Residues choosing a convenient contour for mathematical solution of some important and useful improper integrals for science and technology students. We hope that the detailed resolutions of some basic improper integrals will contribute to the academic training of students who take the discipline of Complex Variables in the areas of Science, Mathematics and Engineering and also for those who intend to pursue a professional, academic career in Teaching and Research

A new and old pandemic – the Burnout Syndrome

The Burnout Syndrome (SB) is known worldwide, but scientific studies only started from the researches made by the American psychologist Freudenberger. Its concept encompasses three dimensions: emotional exhaustion, depersonalization and low professional achievement. It is currently a student in various fields of human knowledge, from Anthropology to Psychology. The area of ​​Psychology that most researchers BS is the Psychodynamics of Work in which they call it "Malaise". However, researchers involving BS under the perspective of Behavior Analysis is scarce in Brazil and in the world. This study aims to analyze BS in several countries, from developed to poor countries, and in this sense supports the thesis that it is a pandemic. It is a study of a theoretical nature, of qualitative, descriptive and bibliographic nature and has as theoretical basis Skinner's Radical BehaviorismThe Burnout Syndrome (SB) is known worldwide, but scientific studies only started from the researches made by the American psychologist Freudenberger. Its concept encompasses three dimensions: emotional exhaustion, depersonalization and low professional achievement. It is currently a student in various fields of human knowledge, from Anthropology to Psychology. The area of ​​Psychology that most researchers BS is the Psychodynamics of Work in which they call it "Malaise". However, researchers involving BS under the perspective of Behavior Analysis is scarce in Brazil and in the world. This study aims to analyze BS in several countries, from developed to poor countries, and in this sense supports the thesis that it is a pandemic. It is a study of a theoretical nature, of qualitative, descriptive and bibliographic nature and has as theoretical basis Skinner's Radical Behavioris

Effects of carbon nanotubes/graphene nanoplatelets hybrid systems on the structure and properties of polyetherimide-based foams

Foams based on polyetherimide (PEI) with carbon nanotubes (CNT) and PEI with graphene nanoplatelets (GnP) combined with CNT were prepared by water vapor induced phase separation. Prior to foaming, variable amounts of only CNT(0.1–2.0wt%) or a combination of GnP(0.0–2.0 wt %) and CNT (0.0–2.0 wt %) for a total amount of CNT-GnP of 2.0 wt %, were dispersed in a solvent using high power sonication, added to the PEI solution, and intensively mixed. While the addition of increasingly higher amounts of only CNT led to foams with more heterogeneous cellular structures, the incorporation of GnP resulted in foams with ¿ner and more homogeneous cellular structures. GnP in combination with CNT effectively enhanced the thermal stability of foams by delaying thermal decomposition and mechanically-reinforced PEI. The addition of 1.0 wt % GnP in combination with 1.0 wt % CNT resulted in foams with extremely high electrical conductivity, which was related to the formation of an optimum conductive network by physical contact between GnP layers and CNT, enabling their use in electrostatic discharge (ESD) and electromagnetic interference (EMI) shielding applications. The experimental electrical conductivity values of foams containing only CNT ¿tted well to a percolative conduction model, with a percolation threshold of 0.06 vol % (0.1 wt %) CNTPostprint (published version

Effects of graphene nanoplatelets and cellular structure on the thermal conductivity of polysulfone nanocomposite foams

Polysulfone (PSU) foams containing 0–10 wt% graphene nanoplatelets (GnP) were prepared using two foaming methods. Alongside the analysis of the cellular structure, their thermal conductivity was measured and analyzed. The results showed that the presence of GnP can a ect the cellular structure of the foams prepared by both water vapor induced phase separation (WVIPS) and supercritical CO2 (scCO2) dissolution; however, the impact is greater in the case of foams prepared by WVIPS. In terms of thermal conductivity, the analysis showed an increasing trend by incrementing the amount of GnP and increasing relative density, with the tortuosity of the cellular structure, dependent on the used foaming method, relative density, and amount of GnP, playing a key role in the final value of thermal conductivity. The combination of all these factors showed the possibility of preparing PSU-GnP foams with enhanced thermal conductivity at lower GnP amount by carefully controlling the cellular structure and relative density, opening up their use in lightweight heat dissipatorsPostprint (published version

Polyetherimide foams filled with low content of graphene nanoplatelets prepared by scCO2 dissolution

Polyetherimide (PEI) foams with graphene nanoplatelets (GnP) were prepared by supercritical carbon dioxide (scCO2) dissolution. Foam precursors were prepared by melt-mixing PEI with variable amounts of ultrasonicated GnP (0.1–2.0 wt %) and foamed by one-step scCO2 foaming. While the addition of GnP did not significantly modify the cellular structure of the foams, melt-mixing and foaming induced a better dispersion of GnP throughout the foams. There were minor changes in the degradation behaviour of the foams with adding GnP. Although the residue resulting from burning increased with augmenting the amount of GnP, foams showed a slight acceleration in their primary stages of degradation with increasing GnP content. A clear increasing trend was observed for the normalized storage modulus of the foams with incrementing density. The electrical conductivity of the foams significantly improved by approximately six orders of magnitude with only adding 1.5 wt % of GnP, related to an improved dispersion of GnP through a combination of ultrasonication, melt-mixing and one-step foaming, leading to the formation of a more effective GnP conductive network. As a result of their final combined properties, PEI-GnP foams could find use in applications such as electrostatic discharge (ESD) or electromagnetic interference (EMI) shieldingPostprint (published version

Visualização de percursos em dispositivos móveis

Cada vez mais as pessoas se deslocam para locais desconhecidos por motivos profissionais, financeiros ou simplesmente por lazer. Em todas estas situações as primeiras dificuldades com que se deparam são saber qual o percurso a adoptar para chegar a um determinado destino e a falta de informação sobre o local onde se encontram, especialmente sobre os possíveis pontos de interesse que existem em redor. O presente trabalho propõe a concepção e a implementação de um sistema de visualização para dispositivos móveis de percursos pré-definidos baseado em standards. Pretende-se construir um software aberto de modo a poder ser utilizado em diversas aplicações geográficas modulares e facilitar a investigação na área, pois a maior parte do software disponibilizado é proprietário havendo apenas hipótese de interagir através de API disponibilizada. O trabalho pretende servir utilizadores que pretendam tirar partido de um guia digital móvel, materializado num dispositivo móvel com capacidade visualização gráfica do percurso. Pode ser utilizado nas mais diversas situações: orientação em trilhos ou rotas turísticas; identificação e orientação de pontos de interesse numa cidade ou região; ou informação de contexto. Para estimular a atenção do utilizador é proposto um mecanismo de alertas/avisos que serão despoletados durante a execução do percurso. Como muitas das funcionalidades disponibilizadas pelo sistema necessitam de efectuar cálculo de distâncias, é proposto um modelo de determinação de distâncias. De modo a gerir o conteúdo dos ficheiros utilizados é proposto um mecanismo de processamento de ficheiros, que permite efectuar transformações, validações e gravações de ficheiros. Para além da concepção e correspondente implementação do Visualizador, este trabalho apresenta ainda cenários de aplicação do sistema, ilustrando consequentemente a sua utilização em situações reais e encontra-se disponível para ser usado e melhorado pela comunidade científica, pois foi feito o registo como open source no site sourceforge.net