Photonics Active Filters Based on SiC Multi layer Structures: A Two Stage Active Circuit

Characteristics of tunable wavelength filters based on a-SiC:H multi-layered stacked cells are studied both theoretically and experimentally. Results show that the light-activated photonic device combines the demultiplexing operation with the simultaneous photodetection and self amplification of an optical signal. The sensor is a bias wavelength current-controlled device that make use of changes in the wavelength of the background to control the power delivered to the load, acting a photonic active filter. Its gain depends on the background wavelength that controls the electrical field profile across the device.

Construção de websites com ferramentas open-source: duas experiências de implementação em bibliotecas de ensino superior

As Tecnologias da Informação e da Comunicação (TIC) têm influenciado de forma inequívoca o desenvolvimento das bibliotecas à escala global. Nas últimas décadas, as TIC mudaram a dinâmica das bibliotecas permitindo a sua modernização (pelo desenvolvimento da eficiência das tarefas já realizadas), favorecendo a inovação (pela utilização das tecnologias como base para o desenvolvimento de novos serviços/técnicas) e promovendo a sua transformação (ao nível do paradigma funcional, da disponibilização de conteúdos, etc.) – criando, em suma, uma nova relação com os seus públicos

Cyanobacteria toxicity: potential public health impact in South Portugal populations

Cyanobacteria are prokaryotic, plantlike organisms present in lakes, recreational waters, and reservoirs, and often dominate phytoplankton communities in warm, nutrient-enriched hard waters. A stable water column rich in certain nutrients, especially nitrogen and phosphorus, is associated with favorable environmental conditions that support development of cyanobacterial population maxima or "blooms." Under specific conditions, cyanobacteria produce toxins that are responsible for acute poisoning and death of animals and humans. The main aim of this study was to correlate the presence of cyanobacteria blooms with potential toxicity to humans as a public health issue. In Portugal, seven reservoirs located in the southern region were selected and studied between 2000 and 2008. Reservoirs were characterized by physical and chemical aspects, and identification of phytoplankton communities. In the case of cyanobacterial blooms, toxins that affected the liver, nervous system, and skin were detected, namely, Microcystis aeruginosa, Aphanizomenon spp., and Oscillatoria. These findings suggest the presence of a potential risk for public health, and indicate the need to implement mitigation measures in all studied reservoirs. These measures may involve (1) water eutrophication control to avoid blooms, (2) appropriate treatment of water for human consumption, and (3) public warnings or information to those individuals that use these reservoirs for several recreational activities.

Fungal contamination in swine: a potential occupational health threat

Poor air quality in a pig-confinement building may potentially place farmers at higher health risk than other workers for exposure to airborne pollutants that may reach infectious levels. The aim of this study was to assess worker exposure to fungi in indoor environments in Portuguese swine buildings. Air samples from 7 swine farms were collected at a flow rate of 140 L/min, at 1 m height, onto malt extract agar supplemented with chloramphenicol (MEA). Surfaces samples of the same indoor sites were obtained by swabbing the surfaces. Samples from the floor covering were also collected from four of seven swine farms. All collected samples were incubated at 27°C for 5-7 days. After lab processing and incubation of obtained samples, quantitative colony-forming units (CFU)/m(3), CFU/cm(2), and CFU/g and qualitative results were determined with identification of isolated fungal species. Aspergillus versicolor was the most frequent species found in air (21%), followed by Scopulariopsis brevicaulis (17%) and Penicillium sp. (14%). Aspergillus versicolor was also the most frequent species noted on surfaces (26.6%), followed by Cladosporium sp. (22.4%) and Scopulariopsis brevicaulis (17.5%). Chrysosporium was the most frequently found genera in the new floor covering (38.5%), while Mucor was the most prevalent genera (25.1%) in used floor covering. Our findings corroborate a potential occupational health threat due to fungi exposure and suggest the need for a preventive strategy.

New syntheses of potential biologically active xanthones and benzoxanthones

10º Encontro Nacional de Química Orgânica e 1º Simpósio Luso-Brasileiro de Química Orgânica, Lisboa, 4-6 Setembro de 2013.

Segurança contra intrusão em redes informáticas

Devido ao facto de hoje em dia a informação que é processada numa rede informática empresarial, ser cada vez mais de ordem confidencial, torna-se necessário que essa informação esteja o mais protegida possível. Ao mesmo tempo, é necessário que esta a informação esteja disponível com a devida rapidez, para os parceiros certos, num mundo cada vez mais globalizado. Com este trabalho pretende-se efectuar o estudo e implementação da segurança, numa pequena e genérica rede de testes, que facilmente seja extrapolada, para uma rede da dimensão, de uma grande empresa com potenciais ramificações por diversos locais. Pretende-se implementar/monitorização segurança quer externamente, (Internet service provider ISP) quer internamente (activos de rede, postos de trabalho/utilizadores). Esta análise é baseada na localização (local, wireless ou remota), e, sempre que seja detectada qualquer anomalia, seja identificada a sua localização, sendo tomadas automaticamente acções de protecção. Estas anomalias poderão ser geridas recorrendo a ferramentas open source ou comerciais, que façam a recolha de toda a informação necessária, e tomem acções de correcção ou alerta mediante o tipo de anomalia.

A Voltage Limiter Circuit for Indoor Light Energy Harvesting Applications

A voltage limiter circuit for indoor light energy harvesting applications is presented. This circuit is a part of a bigger system, whose function is to harvest indoor light energy, process it and store it, so that it can be used at a later time. This processing consists on maximum power point tracking (MPPT) and stepping-up, of the voltage from the photovoltaic (PV) harvester cell. The circuit here described, ensures that even under strong illumination, the generated voltage will not exceed the limit allowed by the technology, avoiding the degradation, or destruction, of the integrated die. A prototype of the limiter circuit was designed in a 130 nm CMOS technology. The layout of the circuit has a total area of 23414 mu m(2). Simulation results, using Spectre, are presented.

Modelling the distribution of cetaceans using opportunistic presence-only data in S. Miguel Island (Azores)

25th Annual Conference of the European Cetacean Society, Cadiz, Spain 21-23 March 2011.

AzoresPhotoID: first results from an open-access photoidentification catalogue

25th Conference of the European Cetacean Society. Long-terms datasets on marine mammals: learning from the past to manage the future, Cadiz, Spain, 21-23 March 2011.

Effective isotropic potential for dipolar hard spheres

A new effective isotropic potential is proposed for the dipolar hard-sphere fluid, on the basis of recent results by others for its angle-averaged radial distribution function. The new effective potential is shown to exhibit oscillations even for moderately high densities and moderately strong dipole moments, which are absent from earlier effective isotropic potentials. The validity and significance of this result are briefly discussed.

Start-up circuit for low-power indoor light energy harvesting applications

A start-up circuit, used in a micro-power indoor light energy harvesting system, is described. This start-up circuit achieves two goals: first, to produce a reset signal, power-on-reset (POR), for the energy harvesting system, and secondly, to temporarily shunt the output of the photovoltaic (PV) cells, to the output node of the system, which is connected to a capacitor. This capacitor is charged to a suitable value, so that a voltage step-up converter starts operating, thus increasing the output voltage to a larger value than the one provided by the PV cells. A prototype of the circuit was manufactured in a 130 nm CMOS technology, occupying an area of only 0.019 mm(2). Experimental results demonstrate the correct operation of the circuit, being able to correctly start-up the system, even when having an input as low as 390 mV using, in this case, an estimated energy of only 5.3 pJ to produce the start-up.

Polycyclic aromatic hydrocarbon levels in three pelagic fish species from Atlantic Ocean: inter-specific and inter-season comparisons and assessment of potential public health risks

The concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) were determined in three commercially valuable fish species (sardine, Sardina pilchardus; chub mackerel, Scomber japonicus; and horse mackerel, Trachurus trachurus) from the Atlantic Ocean. Specimens were collected seasonally during 2007–2009. Only low molecular weight PAHs were detected, namely, naphthalene, acenaphthene, fluorene and phenanthrene. Chub mackerel (1.80–19.90 microg/kg ww) revealed to be significantly more contaminated than horse mackerel (2.73–10.0 microg/kg ww) and sardine (2.29–14.18 microg/kg ww). Inter-specific and inter-season comparisons of PAHs bioaccumulation were statistically assessed. The more relevant statistical correlations were observed between PAH amounts and total fat content (significant positive relationships, p < 0.05), and season (sardine displayed higher amounts in autumn–winter while the mackerel species showed globally the inverse behavior). The health risks by consumption of these species were assessed and shown to present no threat to public health concerning PAH intakes.

Open-source software in operations research in engineering teaching

ENEGI 2013: Atas do 2º Encontro Nacional de Engenharia e Gestão Industrial, Universidade de Aveiro, 17 e 18 de maio de 2013, Aveiro, Portugal.

Potential distribution and cost estimation of the damage caused by Cryptotermes brevis (Isoptera: Kalotermitidae) in the Azores

Copyright © 2014 Entomological Society of America.

Avaliação estratégica de relações públicas em tecnologias de consumo: a Sony Ericsson e o Estoril Open

O relatório que se segue desenvolveu-se em torno das conclusões retiradas relativamente à eficácia da estratégia de comunicação da Sony Ericsson que terminou com uma acção específica no Estoril Open. Para a realização deste estudo definiram-se os objectivos que guiaram o Estágio, assentes no desenho e descrição da estratégia desenvolvida para o evento, de forma a avaliar os resultados que essa estratégia obteve. O Estágio foi realizado na Tinkle, a consultora de comunicação que trabalha com a Sony Ericsson. Para a realização da estratégia foi tido em conta o Ciclo de Vida da Adopção de Tecnologias de Moore (2002), assumindo que a Sony Ericsson opera principalmente num Mercado Maioritário, onde está presente a Maioria Inicial. A estratégia teve assim como principal objectivo o reconhecimento, a associação da marca ao ténis feminino, a aproximação a um público específico e a apresentação dos equipamentos recentes. A avaliação estratégica desenvolveu-se com as ferramentas de Output, Outtake e Outcome. Aqui destaca-se a dificuldade em medir o Outcome, assim como a medição do Outtake que também fora limitada devido aos critérios escolhidos. As dificuldades na avaliação da estratégia estiveram assim intimamente relacionadas com a falta de uma definição de objectivos claros em termos de Outcome e Outtake, mas também com a falta de critérios de medição de Output. Por fim, resta salientar a importância da continuidade deste estudo em futuras investigações para se concluir objectivamente sobre a activação da Sony Ericsson em Portugal, relativamente ao ténis feminino.