Browsing by Issue Date, starting with "2012-05"
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- Optimizing the location of weather monitoring stations using estimation uncertaintyPublication . Amorim, Ana M. T.; Gonçalves, Alexandre B.; Nunes, Luis Miguel; Sousa, António JorgeIn this article, we address the problem of planning a network of weather monitoring stations observing average air temperature (AAT). Assuming the network planning scenario as a location problem, an optimization model and an operative methodology are proposed. The model uses the geostatistical uncertainty of estimation and the indicator formalism to consider in the location process a variable demand surface, depending on the spatial arrangement of the stations. This surface is also used to express a spatial representativeness value for each element in the network. It is then possible to locate such a network using optimization techniques, such as the used methods of simulated annealing (SA) and construction heuristics. This new approach was applied in the optimization of the Portuguese network of weather stations monitoring the AAT variable. In this case study, scenarios of reduction in the number of stations were generated and analysed: the uncertainty of estimation was computed, interpreted and applied to model the varying demand surface that is used in the optimization process. Along with the determination of spatial representativeness value of individual stations, SA was used to detect redundancies on the existing network and establish the base for its expansion. Using a greedy algorithm, a new network for monitoring average temperature in the selected study area is proposed and its effectiveness is compared with the current distribution of stations. For this proposed network distribution maps of the uncertainty of estimation and the temperature distribution were created. Copyright (c) 2011 Royal Meteorological Society
- Overexpression of four and a half LIM domains protein 2 promotes epithelial-mesenchymal transition-like phenotype in fish pre-osteoblastsPublication . Rafael, Marta S.; Laizé, Vincent; Florindo, C.; Ferraresso, Serena; Bargelloni, Luca; Cancela, LeonorFHL2 is a multifunctional protein involved in gene transcription regulation and cytoarchitecture modulation that has been recently associated with epithelial-mesenchymal transition (EMT) in colon cancer. Overexpression of FHL2 in a fish pre-osteoblastic cell line promoted cell dedifferentiation and impaired its extracellular matrix mineralization capacity. Cell cultures also acquired a novel threedimensional structure organization, their proliferation rate was enhanced and gene expression profile was altered in agreement with an EMT-like phenotype upon overexpression of FHL2. Altogether, our results provide additional support to the relevance of FHL2 for cell differentiation and its association with hallmarks of cancer phenotype.
- Chitosan-Hyaluronic acid hybrid vectors for retinal gene therapyPublication . Oliveira, Ana; Bitoque, Diogo; Silva, Gabriela A.
- Midgut microbiota of the malaria mosquito vector Anopheles gambiae and Interactions with plasmodium falciparum InfectionPublication . Boissiere, Anne; Tchioffo, Majoline T.; Bachar, Dipankar; Abate, Luc; Marie, Alexandra; Nsango, Sandrine E.; Shahbazkia, Hamid R.; Awono-Ambene, Parfait H.; Levashina, Elena A.; Christen, Richard; Morlais, IsabelleThe susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission.
- Modelo de escoamento e combustão de biomassa em grelhaPublication . Sousa, Nelson; Azevedo, João L. T.Este trabalho apresenta a formulação de um modelo de simulação de combustão de biomassa em grelha. O modelo inclui várias aproximações para cada um dos processos considerados, nomeadamente, o movimento dos sólidos já apresentado noutro artigo e o escoamento de gases através de meio granular, considerando a equação de Forchheimer. Para descrever a evolução das propriedades nos sólidos utiliza-se um modelo unidimensional para aproximar as partículas de combustível que é comparado com um modelo detalhado. Apresenta-se ainda o algoritmo em desenvolvimento para acoplar os diversos submodelos e a inclusão de balanços de energia e de massa com recção química.
- Turismo sustentável e valorização patrimonial. A (re)construção da viagem filosófica de Alexandre Rodrigues Ferreira – o primeiro naturalista portuguêsPublication . Henriques, CláudiaNeste artigo reflete-se sobre a relação, cada vez mais estreita, entre turismo e cultura. A Viagem Filosófica de Alexandre Rodrigues Ferreira na Amazónia enquanto património identitário de uma região é aqui perspetivada como potencializadora de itinerários turistico culturais.
- Do inquérito à arquitetura regional portuguesa à investigação local aplicada: a experiência do GTAA Sotavento nos domínios da investigação sobre o património vernacular construídoPublication . Ribeiro, Vítor; Aguiar, José; Costa, Miguel ReimãoAo longo dos anos 90 do século passado foram lançadas diversas iniciativas orientadas ao desenvolvimento local em espaço rural e à revitalização e reabilitação dos núcleos populacionais, nas quais era conferido particular destaque à valorização do património vernacular construído. Estas iniciativas inserem-se num processo mais amplo de regresso a uma certa ideia de ruralidade – agora mais simbólica que agrícola – e de afirmação das raízes identitárias como factor de valorização endógena construída a partir da “descoberta” do património como recurso a considerar no âmbito da diversificação económica associada às novas dinâmicas emergentes, de que o Programa das Aldeias Históricas viria a constituir a ação-piloto. Seguindo os caminhos abertos por aquela iniciativa, o Programa de Revitalização das Aldeias do Algarve visava estender a esta região a estratégia, os objectivos e os princípios, bem como o conjunto de práticas de intervenção que lhe estavam associadas. A criação do Gabinete Técnico de Apoio às Aldeias do Sotavento (GTAA Sotavento) constituiu, nesse âmbito particular, oportunidade única de testar uma prática sistemática de investigação, formação e habilitação técnica nos domínios específicos do património vernacular construído procurando contribuir, entre outros e nomeadamente, para necessária transposição de escalas de investigação nos domínios do património vernacular construído: da mais genérica e territorial - a está precisamente associada ao Inquérito à Arquitetura Regional Portuguesa - a uma mais específica, local e particular, essencial ao suporte da prática de projeto e intervenção nestas áreas. O presente artigo procura, assim, integrar a prática de investigação levada a cabo pelo GTAA Sotavento no contexto genérico em que se insere o Inquérito, e demonstrar a sua importância no desenvolvimento da respectiva prática projetual, de forma a contribuir para a discussão e definição de modelos de práticas de intervenção em áreas e núcleos rurais.
- A spectrally efficient transmission scheme for signals with large bandwidthPublication . Silva, Paulo; Dinis, RuiIn this paper we consider single-carrier with frequency-domain equalization (SC-FDE) schemes where the transmission bandwidth is above the symbol rate. To allow high spectral efficiencies, several channels share the same bandwidth. Since the co-channel interference (CCI) levels can be very high, we propose iterative FDE receivers where we jointly detect all users sharing the same channel. Our performance results show that we can have excellent performances, even with several users sharing the same channel. In fact, we can have the maximum theoretical spectral efficiency even with signals that have bandwidth substantially above the symbol rate.
- The role of built rural heritage in the contemporary landscape of Central AlgarvePublication . Costa, Miguel Reimão; Batista, DesidérioTraditional rural settlements and various landscape structures are increasingly thought to be valuable heritage as part of cultural landscapes. This paper examines questions related to the conservation and rehabilitation of this heritage, highlighting the contrasting circumstances in urban regions and depopulated interior zones. To this end, this paper looks at the central zone of the Algarve in the south of Portugal, which is notable for its remarkable diversity of typology in rural settlements and in landscape units. Based on a brief description of the traditional economy in these diverse regional areas, the principles for preserving built rural heritage are presented in the context of contemporary landscape transformation.
- Dynamics of plasmodium falciparum selection after Artemether-Lumefantrine treatment in AfricaPublication . Ferreira, Pedro Eduardo; Culleton, Richard