A nova realidade da presença chinesa em Angola e suas implicações para Portugal : o sector da construção civil e obras públicas como estudo de caso

O reforço da presença económica chinesa em África constitui uma das principais alterações nas relações económicas internacionais da pre‑ sente década e, como tal, o respectivo impacto tem vindo a ser objecto de discussão numa larga variedade de sectores e de países. Neste contexto, pretende‑se, com o presente ar‑ tigo, dar a conhecer os principais contornos do envolvimento da China em Angola, dedicando particular atenção ao sector da construção e obras públicas. Do mesmo modo, tratando‑se de um sector de tradicional importância para Portugal no seu relacionamento com Angola, discutir‑se‑á em que medida a entrada das construtoras chinesas no mercado angolano estará ou não a afectar, de forma significativa, a actividade das empresas portuguesas

Optimization of a p-persistent Network Diversity Multiple Access Protocol for a SC-FDE System

This paper presents a Medium Access Control (MAC) protocol solution designed to properly handle collisions when in the presence of a multi-packet detection receiver for Single-Carrier (SC) modulations with Frequency-Domain Equalization (FDE). It is considered an iterative frequency-domain receiver that jointly performs equalization, multi-packet separation and channel decoding operations, for up to Qmax mobile terminals transmitting in one slot. In this work, it is proposed and evaluated a p-persistent Network Diversity Multiple Access (NDMA) random MAC protocol designed to cope with a total number of mobile terminals J, for a maximum decoding capability of Qmax simultaneous packets. An accurate analytical model is presented to optimize two different scenarios: in the first one, a saturated network is considered and it is determined the packet transmission probability that maximizes the uplink throughput; the second represents a non-saturated network and the goal is to compute the optimal transmission probability associated to each mobile terminal that minimizes the packet transmission delay. In the end, analytical results obtained through physical and MAC layer simulations are discussed

The institutional challenges for the European Union in the face of the new chinese investment wave

By analysing the historical picture between China and the European Union, focusing on their trade and economic relations, and discussing the consequences of Chinese trade and investment in Europe, this paper aims to analyse the consequences of Chinese investment in Europe, how it is challenging the European unity, its institutional structure and its foreign policy towards China

Discovery and implementation of a novel pathway for n-butanol production via 2-oxoglutarate

Background: One of the European Union directives indicates that 10% of all fuels must be bio-synthesized by 2020. In this regard, biobutanol - natively produced by clostridial strains - poses as a promising alternative biofuel. One possible approach to overcome the difficulties of the industrial exploration of the native producers is the expression of more suitable pathways in robust microorganisms such as Escherichia coli. The enumeration of novel pathways is a powerful tool, allowing to identify non-obvious combinations of enzymes to produce a target compound. Results: This work describes the in silico driven design of E. coli strains able to produce butanol via 2-oxoglutarate by a novel pathway. This butanol pathway was generated by a hypergraph algorithm and selected from an initial set of 105,954 different routes by successively applying different filters, such as stoichiometric feasibility, size and novelty. The implementation of this pathway involved seven catalytic steps and required the insertion of nine heterologous genes from various sources in E. coli distributed in three plasmids. Expressing butanol genes in E. coli K12 and cultivation in High-Density Medium formulation seem to favor butanol accumulation via the 2-oxoglutarate pathway. The maximum butanol titer obtained was 85 \ub1 1 mg L-1 by cultivating the cells in bioreactors. Conclusions: In this work, we were able to successfully translate the computational analysis into in vivo applications, designing novel strains of E. coli able to produce n-butanol via an innovative pathway. Our results demonstrate that enumeration algorithms can broad the spectrum of butanol producing pathways. This validation encourages further research to other target compounds

Pre-school science education in Portugal: teacher education and innovative practices

Assuming science education in the early years as the stepping stone for the development of scientific and technological literacy, a teacher training program was developed with six kindergarten teachers in Portugal. Its aim was to promote the (re)construction of their subject content and pedagogical knowledge leading to innovative practices, based on the characterization of their profile, shortcomings and practices. Learning through practice was considered the most effective means to promote change in kindergarten teachers’ curricular approaches to science, hence the development of practical activities focusing on children’s understanding and requiring their scientific knowledge and enquiry processes. These include a teacher’s guide (presenting its objectives, concepts and teaching, learning and assessment strategies), a theoretical framework (presenting the concepts, known misconceptions and research references) and also the necessary didactic resources. The paper details the results of the developed teacher training program as well of the validation process of the designed teaching strategies

TNA4OptFlux : a software tool for the analysis of strain optimization strategies

BACKGROUND:Rational approaches for Metabolic Engineering (ME) deal with the identification of modifications that improve the microbes' production capabilities of target compounds. One of the major challenges created by strain optimization algorithms used in these ME problems is the interpretation of the changes that lead to a given overproduction. Often, a single gene knockout induces changes in the fluxes of several reactions, as compared with the wild-type, and it is therefore difficult to evaluate the physiological differences of the in silico mutant. This is aggravated by the fact that genome-scale models per se are difficult to visualize, given the high number of reactions and metabolites involved.FINDINGS:We introduce a software tool, the Topological Network Analysis for OptFlux (TNA4OptFlux), a plug-in which adds to the open-source ME platform OptFlux the capability of creating and performing topological analysis over metabolic networks. One of the tool's major advantages is the possibility of using these tools in the analysis and comparison of simulated phenotypes, namely those coming from the results of strain optimization algorithms. We illustrate the capabilities of the tool by using it to aid the interpretation of two E. coli strains designed in OptFlux for the overproduction of succinate and glycine.CONCLUSIONS:Besides adding new functionalities to the OptFlux software tool regarding topological analysis, TNA4OptFlux methods greatly facilitate the interpretation of non-intuitive ME strategies by automating the comparison between perturbed and non-perturbed metabolic networks. The plug-in is available on the web site http://www.optflux.org webcite, together with extensive documentation.This work is funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT (Portuguese Foundation for Science and Technology) within projects ref. COMPETE FCOMP-01-0124-FEDER-015079 and PEst-OE/EEI/UI0752/2011. JPP and RP work is funded by PhD grants from the Portuguese FCT (ref. SFRH/BD/41763/ 2007 and SFRH/BD/51111/2010)

Comportamento voltamétrico de perilenos bismides modificados em GCE e SPE

Uma das necessidades mais emergentes no planeta é a deteção e quantificação de diversos analitos prejudiciais aos seres vivos, presentes no meio ambiente, de uma forma rápida, com baixo custo e com elevada seletividade. Os screen printed electrodes (SPE) têm sido usados extensivamente como transdutores de sensores químicos para vários analitos importantes. A modificação da superfície dos SPEs com moléculas capazes de fazer o reconhecimento de diversos analitos traduz-se no aumento da seletividade do elétrodo, devido às interações entre as duas espécies [1]. Entre as técnicas de imobilização (covalente e não covalente) de moléculas na superfície dos SPE, destacamos a modificação não covalente, visto este ser um método rápido, com elevada reprodutibilidade, de baixo custo, e sem a necessidade de reações violentas para a superfície do sensor para formar a ligação covalente. A utilização de moléculas com estruturas capazes de formar ligações π com nanoestruturas de carbono [2] é uma vantagem, pois permite a adsorção de espécies que irão fazer o reconhecimento de analitos sem danificar a superfície da matriz principal mantendo assim as excelentes características das nanoestruras de carbono, como os nanotubos de carbono e as folhas de grafeno. (...

Rumex induratus leaves: phytochemical profiling and antioxidant activity

Several species of the Rumex (Polygonaceae) genus have been used in traditional medicine, although their high oxalic acid content has been implicated in oxalic intoxication, mainly la children. Rumex induratus Boiss & Reuter is an endemic Liberian herb that prefers rocky habitats of the thermo Mediterranean region

Fine-scale survey of intertidal macroalgae reveals recent changes in a cold-water biogeographic stronghold

Global warming has been causing severe impacts on marine ecosystems, a notorious one being shifts in the geographical ranges of species. The north-western coast of the Iberian Peninsula is an especially interesting zone to study distributional shifts as it has a strong latitudinal thermal gradient, is influenced by the Canary upwelling system (which partially cancels coastal warming) and holds some of the most diverse macroalgae communities in Europe. Notably, it is within this region that many cold-water species, common in northern Europe, have their southernmost distribution refuge. Recent studies hypothesize that the environmental conditions may be nonetheless changing and already threatening this biodiversity hotspot. The main goal of this study was to carry out a fine-scale assessment of the distributional limits of several macroalgae in North-western Iberia, as well as identify possible population and range shifts using historical data (2001-2005) as reference. In addition, non-indigenous species were also surveyed. We also assessed if the regions of (i) Galicia, (ii) Northern Portugal, and (iii) Central Portugal displayed distinctive characters regarding macroalgae composition and abundance. We identified an increase in abundance of some non-indigenous macroalgae as well as a decrease in the abundance of some cold-water species. In the most severe cases, cold-water species were extirpated along hundreds of km. The compounded effect of the decrease in the abundance of cold-water species and the increase in the abundance of non-indigenous species is leading to the homogenization of macroalgae communities in north-western Iberia